Move lockdep.c, lockdep_internals.h and lock_proc.c to instrumentation/.
Should we move the lockdep Kconfig menu entry to Instrumentation support? It is
currently automatically selected by "Kernel debugging" in Kernel hacking.
Signed-off-by: Mathieu Desnoyers <[email protected]>
CC: Ingo Molnar <[email protected]>
CC: Peter Zijlstra <[email protected]>
---
instrumentation/Makefile | 4
instrumentation/lockdep.c | 3217 ++++++++++++++++++++++++++++++++++++
instrumentation/lockdep_internals.h | 78
instrumentation/lockdep_proc.c | 683 +++++++
kernel/Makefile | 4
kernel/lockdep.c | 3217 ------------------------------------
kernel/lockdep_internals.h | 78
kernel/lockdep_proc.c | 683 -------
8 files changed, 3982 insertions(+), 3982 deletions(-)
Index: linux-2.6-lttng.stable/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/instrumentation/Makefile 2007-10-29 09:52:30.000000000 -0400
+++ linux-2.6-lttng.stable/instrumentation/Makefile 2007-10-29 09:52:58.000000000 -0400
@@ -6,3 +6,7 @@ obj-y += profile.o
obj-$(CONFIG_KPROBES) += kprobes.o
obj-$(CONFIG_MARKERS) += marker.o
+obj-$(CONFIG_LOCKDEP) += lockdep.o
+ifeq ($(CONFIG_PROC_FS),y)
+obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
+endif
Index: linux-2.6-lttng.stable/instrumentation/lockdep.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/instrumentation/lockdep.c 2007-10-29 09:52:35.000000000 -0400
@@ -0,0 +1,3217 @@
+/*
+ * kernel/lockdep.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <[email protected]>
+ * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <[email protected]>
+ *
+ * this code maps all the lock dependencies as they occur in a live kernel
+ * and will warn about the following classes of locking bugs:
+ *
+ * - lock inversion scenarios
+ * - circular lock dependencies
+ * - hardirq/softirq safe/unsafe locking bugs
+ *
+ * Bugs are reported even if the current locking scenario does not cause
+ * any deadlock at this point.
+ *
+ * I.e. if anytime in the past two locks were taken in a different order,
+ * even if it happened for another task, even if those were different
+ * locks (but of the same class as this lock), this code will detect it.
+ *
+ * Thanks to Arjan van de Ven for coming up with the initial idea of
+ * mapping lock dependencies runtime.
+ */
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/stacktrace.h>
+#include <linux/debug_locks.h>
+#include <linux/irqflags.h>
+#include <linux/utsname.h>
+#include <linux/hash.h>
+
+#include <asm/sections.h>
+
+#include "lockdep_internals.h"
+
+#ifdef CONFIG_PROVE_LOCKING
+int prove_locking = 1;
+module_param(prove_locking, int, 0644);
+#else
+#define prove_locking 0
+#endif
+
+#ifdef CONFIG_LOCK_STAT
+int lock_stat = 1;
+module_param(lock_stat, int, 0644);
+#else
+#define lock_stat 0
+#endif
+
+/*
+ * lockdep_lock: protects the lockdep graph, the hashes and the
+ * class/list/hash allocators.
+ *
+ * This is one of the rare exceptions where it's justified
+ * to use a raw spinlock - we really dont want the spinlock
+ * code to recurse back into the lockdep code...
+ */
+static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+
+static int graph_lock(void)
+{
+ __raw_spin_lock(&lockdep_lock);
+ /*
+ * Make sure that if another CPU detected a bug while
+ * walking the graph we dont change it (while the other
+ * CPU is busy printing out stuff with the graph lock
+ * dropped already)
+ */
+ if (!debug_locks) {
+ __raw_spin_unlock(&lockdep_lock);
+ return 0;
+ }
+ return 1;
+}
+
+static inline int graph_unlock(void)
+{
+ if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
+ return DEBUG_LOCKS_WARN_ON(1);
+
+ __raw_spin_unlock(&lockdep_lock);
+ return 0;
+}
+
+/*
+ * Turn lock debugging off and return with 0 if it was off already,
+ * and also release the graph lock:
+ */
+static inline int debug_locks_off_graph_unlock(void)
+{
+ int ret = debug_locks_off();
+
+ __raw_spin_unlock(&lockdep_lock);
+
+ return ret;
+}
+
+static int lockdep_initialized;
+
+unsigned long nr_list_entries;
+static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
+
+/*
+ * All data structures here are protected by the global debug_lock.
+ *
+ * Mutex key structs only get allocated, once during bootup, and never
+ * get freed - this significantly simplifies the debugging code.
+ */
+unsigned long nr_lock_classes;
+static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+
+#ifdef CONFIG_LOCK_STAT
+static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
+
+static int lock_contention_point(struct lock_class *class, unsigned long ip)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
+ if (class->contention_point[i] == 0) {
+ class->contention_point[i] = ip;
+ break;
+ }
+ if (class->contention_point[i] == ip)
+ break;
+ }
+
+ return i;
+}
+
+static void lock_time_inc(struct lock_time *lt, s64 time)
+{
+ if (time > lt->max)
+ lt->max = time;
+
+ if (time < lt->min || !lt->min)
+ lt->min = time;
+
+ lt->total += time;
+ lt->nr++;
+}
+
+static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
+{
+ dst->min += src->min;
+ dst->max += src->max;
+ dst->total += src->total;
+ dst->nr += src->nr;
+}
+
+struct lock_class_stats lock_stats(struct lock_class *class)
+{
+ struct lock_class_stats stats;
+ int cpu, i;
+
+ memset(&stats, 0, sizeof(struct lock_class_stats));
+ for_each_possible_cpu(cpu) {
+ struct lock_class_stats *pcs =
+ &per_cpu(lock_stats, cpu)[class - lock_classes];
+
+ for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
+ stats.contention_point[i] += pcs->contention_point[i];
+
+ lock_time_add(&pcs->read_waittime, &stats.read_waittime);
+ lock_time_add(&pcs->write_waittime, &stats.write_waittime);
+
+ lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
+ lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+
+ for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
+ stats.bounces[i] += pcs->bounces[i];
+ }
+
+ return stats;
+}
+
+void clear_lock_stats(struct lock_class *class)
+{
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct lock_class_stats *cpu_stats =
+ &per_cpu(lock_stats, cpu)[class - lock_classes];
+
+ memset(cpu_stats, 0, sizeof(struct lock_class_stats));
+ }
+ memset(class->contention_point, 0, sizeof(class->contention_point));
+}
+
+static struct lock_class_stats *get_lock_stats(struct lock_class *class)
+{
+ return &get_cpu_var(lock_stats)[class - lock_classes];
+}
+
+static void put_lock_stats(struct lock_class_stats *stats)
+{
+ put_cpu_var(lock_stats);
+}
+
+static void lock_release_holdtime(struct held_lock *hlock)
+{
+ struct lock_class_stats *stats;
+ s64 holdtime;
+
+ if (!lock_stat)
+ return;
+
+ holdtime = sched_clock() - hlock->holdtime_stamp;
+
+ stats = get_lock_stats(hlock->class);
+ if (hlock->read)
+ lock_time_inc(&stats->read_holdtime, holdtime);
+ else
+ lock_time_inc(&stats->write_holdtime, holdtime);
+ put_lock_stats(stats);
+}
+#else
+static inline void lock_release_holdtime(struct held_lock *hlock)
+{
+}
+#endif
+
+/*
+ * We keep a global list of all lock classes. The list only grows,
+ * never shrinks. The list is only accessed with the lockdep
+ * spinlock lock held.
+ */
+LIST_HEAD(all_lock_classes);
+
+/*
+ * The lockdep classes are in a hash-table as well, for fast lookup:
+ */
+#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
+#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
+#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
+#define classhashentry(key) (classhash_table + __classhashfn((key)))
+
+static struct list_head classhash_table[CLASSHASH_SIZE];
+
+/*
+ * We put the lock dependency chains into a hash-table as well, to cache
+ * their existence:
+ */
+#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
+#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
+#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
+#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
+
+static struct list_head chainhash_table[CHAINHASH_SIZE];
+
+/*
+ * The hash key of the lock dependency chains is a hash itself too:
+ * it's a hash of all locks taken up to that lock, including that lock.
+ * It's a 64-bit hash, because it's important for the keys to be
+ * unique.
+ */
+#define iterate_chain_key(key1, key2) \
+ (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
+ ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
+ (key2))
+
+void lockdep_off(void)
+{
+ current->lockdep_recursion++;
+}
+
+EXPORT_SYMBOL(lockdep_off);
+
+void lockdep_on(void)
+{
+ current->lockdep_recursion--;
+}
+
+EXPORT_SYMBOL(lockdep_on);
+
+/*
+ * Debugging switches:
+ */
+
+#define VERBOSE 0
+#define VERY_VERBOSE 0
+
+#if VERBOSE
+# define HARDIRQ_VERBOSE 1
+# define SOFTIRQ_VERBOSE 1
+#else
+# define HARDIRQ_VERBOSE 0
+# define SOFTIRQ_VERBOSE 0
+#endif
+
+#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
+/*
+ * Quick filtering for interesting events:
+ */
+static int class_filter(struct lock_class *class)
+{
+#if 0
+ /* Example */
+ if (class->name_version == 1 &&
+ !strcmp(class->name, "lockname"))
+ return 1;
+ if (class->name_version == 1 &&
+ !strcmp(class->name, "&struct->lockfield"))
+ return 1;
+#endif
+ /* Filter everything else. 1 would be to allow everything else */
+ return 0;
+}
+#endif
+
+static int verbose(struct lock_class *class)
+{
+#if VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the graph_lock.
+ */
+unsigned long nr_stack_trace_entries;
+static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
+
+static int save_trace(struct stack_trace *trace)
+{
+ trace->nr_entries = 0;
+ trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
+ trace->entries = stack_trace + nr_stack_trace_entries;
+
+ trace->skip = 3;
+
+ save_stack_trace(trace);
+
+ trace->max_entries = trace->nr_entries;
+
+ nr_stack_trace_entries += trace->nr_entries;
+
+ if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+
+ return 0;
+ }
+
+ return 1;
+}
+
+unsigned int nr_hardirq_chains;
+unsigned int nr_softirq_chains;
+unsigned int nr_process_chains;
+unsigned int max_lockdep_depth;
+unsigned int max_recursion_depth;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+/*
+ * We cannot printk in early bootup code. Not even early_printk()
+ * might work. So we mark any initialization errors and printk
+ * about it later on, in lockdep_info().
+ */
+static int lockdep_init_error;
+static unsigned long lockdep_init_trace_data[20];
+static struct stack_trace lockdep_init_trace = {
+ .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
+ .entries = lockdep_init_trace_data,
+};
+
+/*
+ * Various lockdep statistics:
+ */
+atomic_t chain_lookup_hits;
+atomic_t chain_lookup_misses;
+atomic_t hardirqs_on_events;
+atomic_t hardirqs_off_events;
+atomic_t redundant_hardirqs_on;
+atomic_t redundant_hardirqs_off;
+atomic_t softirqs_on_events;
+atomic_t softirqs_off_events;
+atomic_t redundant_softirqs_on;
+atomic_t redundant_softirqs_off;
+atomic_t nr_unused_locks;
+atomic_t nr_cyclic_checks;
+atomic_t nr_cyclic_check_recursions;
+atomic_t nr_find_usage_forwards_checks;
+atomic_t nr_find_usage_forwards_recursions;
+atomic_t nr_find_usage_backwards_checks;
+atomic_t nr_find_usage_backwards_recursions;
+# define debug_atomic_inc(ptr) atomic_inc(ptr)
+# define debug_atomic_dec(ptr) atomic_dec(ptr)
+# define debug_atomic_read(ptr) atomic_read(ptr)
+#else
+# define debug_atomic_inc(ptr) do { } while (0)
+# define debug_atomic_dec(ptr) do { } while (0)
+# define debug_atomic_read(ptr) 0
+#endif
+
+/*
+ * Locking printouts:
+ */
+
+static const char *usage_str[] =
+{
+ [LOCK_USED] = "initial-use ",
+ [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W",
+ [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W",
+ [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W",
+ [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W",
+ [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R",
+ [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R",
+ [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R",
+ [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R",
+};
+
+const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
+{
+ return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
+}
+
+void
+get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4)
+{
+ *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.';
+
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
+ *c1 = '+';
+ else
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
+ *c1 = '-';
+
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
+ *c2 = '+';
+ else
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
+ *c2 = '-';
+
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
+ *c3 = '-';
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) {
+ *c3 = '+';
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
+ *c3 = '?';
+ }
+
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
+ *c4 = '-';
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) {
+ *c4 = '+';
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
+ *c4 = '?';
+ }
+}
+
+static void print_lock_name(struct lock_class *class)
+{
+ char str[KSYM_NAME_LEN], c1, c2, c3, c4;
+ const char *name;
+
+ get_usage_chars(class, &c1, &c2, &c3, &c4);
+
+ name = class->name;
+ if (!name) {
+ name = __get_key_name(class->key, str);
+ printk(" (%s", name);
+ } else {
+ printk(" (%s", name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ if (class->subclass)
+ printk("/%d", class->subclass);
+ }
+ printk("){%c%c%c%c}", c1, c2, c3, c4);
+}
+
+static void print_lockdep_cache(struct lockdep_map *lock)
+{
+ const char *name;
+ char str[KSYM_NAME_LEN];
+
+ name = lock->name;
+ if (!name)
+ name = __get_key_name(lock->key->subkeys, str);
+
+ printk("%s", name);
+}
+
+static void print_lock(struct held_lock *hlock)
+{
+ print_lock_name(hlock->class);
+ printk(", at: ");
+ print_ip_sym(hlock->acquire_ip);
+}
+
+static void lockdep_print_held_locks(struct task_struct *curr)
+{
+ int i, depth = curr->lockdep_depth;
+
+ if (!depth) {
+ printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
+ return;
+ }
+ printk("%d lock%s held by %s/%d:\n",
+ depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
+
+ for (i = 0; i < depth; i++) {
+ printk(" #%d: ", i);
+ print_lock(curr->held_locks + i);
+ }
+}
+
+static void print_lock_class_header(struct lock_class *class, int depth)
+{
+ int bit;
+
+ printk("%*s->", depth, "");
+ print_lock_name(class);
+ printk(" ops: %lu", class->ops);
+ printk(" {\n");
+
+ for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
+ if (class->usage_mask & (1 << bit)) {
+ int len = depth;
+
+ len += printk("%*s %s", depth, "", usage_str[bit]);
+ len += printk(" at:\n");
+ print_stack_trace(class->usage_traces + bit, len);
+ }
+ }
+ printk("%*s }\n", depth, "");
+
+ printk("%*s ... key at: ",depth,"");
+ print_ip_sym((unsigned long)class->key);
+}
+
+/*
+ * printk all lock dependencies starting at <entry>:
+ */
+static void print_lock_dependencies(struct lock_class *class, int depth)
+{
+ struct lock_list *entry;
+
+ if (DEBUG_LOCKS_WARN_ON(depth >= 20))
+ return;
+
+ print_lock_class_header(class, depth);
+
+ list_for_each_entry(entry, &class->locks_after, entry) {
+ if (DEBUG_LOCKS_WARN_ON(!entry->class))
+ return;
+
+ print_lock_dependencies(entry->class, depth + 1);
+
+ printk("%*s ... acquired at:\n",depth,"");
+ print_stack_trace(&entry->trace, 2);
+ printk("\n");
+ }
+}
+
+static void print_kernel_version(void)
+{
+ printk("%s %.*s\n", init_utsname()->release,
+ (int)strcspn(init_utsname()->version, " "),
+ init_utsname()->version);
+}
+
+static int very_verbose(struct lock_class *class)
+{
+#if VERY_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+/*
+ * Is this the address of a static object:
+ */
+static int static_obj(void *obj)
+{
+ unsigned long start = (unsigned long) &_stext,
+ end = (unsigned long) &_end,
+ addr = (unsigned long) obj;
+#ifdef CONFIG_SMP
+ int i;
+#endif
+
+ /*
+ * static variable?
+ */
+ if ((addr >= start) && (addr < end))
+ return 1;
+
+#ifdef CONFIG_SMP
+ /*
+ * percpu var?
+ */
+ for_each_possible_cpu(i) {
+ start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
+ end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
+ + per_cpu_offset(i);
+
+ if ((addr >= start) && (addr < end))
+ return 1;
+ }
+#endif
+
+ /*
+ * module var?
+ */
+ return is_module_address(addr);
+}
+
+/*
+ * To make lock name printouts unique, we calculate a unique
+ * class->name_version generation counter:
+ */
+static int count_matching_names(struct lock_class *new_class)
+{
+ struct lock_class *class;
+ int count = 0;
+
+ if (!new_class->name)
+ return 0;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ if (new_class->key - new_class->subclass == class->key)
+ return class->name_version;
+ if (class->name && !strcmp(class->name, new_class->name))
+ count = max(count, class->name_version);
+ }
+
+ return count + 1;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ /*
+ * If the architecture calls into lockdep before initializing
+ * the hashes then we'll warn about it later. (we cannot printk
+ * right now)
+ */
+ if (unlikely(!lockdep_initialized)) {
+ lockdep_init();
+ lockdep_init_error = 1;
+ save_stack_trace(&lockdep_init_trace);
+ }
+#endif
+
+ /*
+ * Static locks do not have their class-keys yet - for them the key
+ * is the lock object itself:
+ */
+ if (unlikely(!lock->key))
+ lock->key = (void *)lock;
+
+ /*
+ * NOTE: the class-key must be unique. For dynamic locks, a static
+ * lock_class_key variable is passed in through the mutex_init()
+ * (or spin_lock_init()) call - which acts as the key. For static
+ * locks we use the lock object itself as the key.
+ */
+ BUILD_BUG_ON(sizeof(struct lock_class_key) >
+ sizeof(struct lockdep_map));
+
+ key = lock->key->subkeys + subclass;
+
+ hash_head = classhashentry(key);
+
+ /*
+ * We can walk the hash lockfree, because the hash only
+ * grows, and we are careful when adding entries to the end:
+ */
+ list_for_each_entry(class, hash_head, hash_entry) {
+ if (class->key == key) {
+ WARN_ON_ONCE(class->name != lock->name);
+ return class;
+ }
+ }
+
+ return NULL;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
+{
+ struct lockdep_subclass_key *key;
+ struct list_head *hash_head;
+ struct lock_class *class;
+ unsigned long flags;
+
+ class = look_up_lock_class(lock, subclass);
+ if (likely(class))
+ return class;
+
+ /*
+ * Debug-check: all keys must be persistent!
+ */
+ if (!static_obj(lock->key)) {
+ debug_locks_off();
+ printk("INFO: trying to register non-static key.\n");
+ printk("the code is fine but needs lockdep annotation.\n");
+ printk("turning off the locking correctness validator.\n");
+ dump_stack();
+
+ return NULL;
+ }
+
+ key = lock->key->subkeys + subclass;
+ hash_head = classhashentry(key);
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ /*
+ * We have to do the hash-walk again, to avoid races
+ * with another CPU:
+ */
+ list_for_each_entry(class, hash_head, hash_entry)
+ if (class->key == key)
+ goto out_unlock_set;
+ /*
+ * Allocate a new key from the static array, and add it to
+ * the hash:
+ */
+ if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
+ if (!debug_locks_off_graph_unlock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ raw_local_irq_restore(flags);
+
+ printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ return NULL;
+ }
+ class = lock_classes + nr_lock_classes++;
+ debug_atomic_inc(&nr_unused_locks);
+ class->key = key;
+ class->name = lock->name;
+ class->subclass = subclass;
+ INIT_LIST_HEAD(&class->lock_entry);
+ INIT_LIST_HEAD(&class->locks_before);
+ INIT_LIST_HEAD(&class->locks_after);
+ class->name_version = count_matching_names(class);
+ /*
+ * We use RCU's safe list-add method to make
+ * parallel walking of the hash-list safe:
+ */
+ list_add_tail_rcu(&class->hash_entry, hash_head);
+
+ if (verbose(class)) {
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+ printk("\nnew class %p: %s", class->key, class->name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ printk("\n");
+ dump_stack();
+
+ raw_local_irq_save(flags);
+ if (!graph_lock()) {
+ raw_local_irq_restore(flags);
+ return NULL;
+ }
+ }
+out_unlock_set:
+ graph_unlock();
+ raw_local_irq_restore(flags);
+
+ if (!subclass || force)
+ lock->class_cache = class;
+
+ if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+ return NULL;
+
+ return class;
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+/*
+ * Allocate a lockdep entry. (assumes the graph_lock held, returns
+ * with NULL on failure)
+ */
+static struct lock_list *alloc_list_entry(void)
+{
+ if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
+ if (!debug_locks_off_graph_unlock())
+ return NULL;
+
+ printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ return NULL;
+ }
+ return list_entries + nr_list_entries++;
+}
+
+/*
+ * Add a new dependency to the head of the list:
+ */
+static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
+ struct list_head *head, unsigned long ip, int distance)
+{
+ struct lock_list *entry;
+ /*
+ * Lock not present yet - get a new dependency struct and
+ * add it to the list:
+ */
+ entry = alloc_list_entry();
+ if (!entry)
+ return 0;
+
+ entry->class = this;
+ entry->distance = distance;
+ if (!save_trace(&entry->trace))
+ return 0;
+
+ /*
+ * Since we never remove from the dependency list, the list can
+ * be walked lockless by other CPUs, it's only allocation
+ * that must be protected by the spinlock. But this also means
+ * we must make new entries visible only once writes to the
+ * entry become visible - hence the RCU op:
+ */
+ list_add_tail_rcu(&entry->entry, head);
+
+ return 1;
+}
+
+/*
+ * Recursive, forwards-direction lock-dependency checking, used for
+ * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
+ * checking.
+ *
+ * (to keep the stackframe of the recursive functions small we
+ * use these global variables, and we also mark various helper
+ * functions as noinline.)
+ */
+static struct held_lock *check_source, *check_target;
+
+/*
+ * Print a dependency chain entry (this is only done when a deadlock
+ * has been detected):
+ */
+static noinline int
+print_circular_bug_entry(struct lock_list *target, unsigned int depth)
+{
+ if (debug_locks_silent)
+ return 0;
+ printk("\n-> #%u", depth);
+ print_lock_name(target->class);
+ printk(":\n");
+ print_stack_trace(&target->trace, 6);
+
+ return 0;
+}
+
+/*
+ * When a circular dependency is detected, print the
+ * header first:
+ */
+static noinline int
+print_circular_bug_header(struct lock_list *entry, unsigned int depth)
+{
+ struct task_struct *curr = current;
+
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n=======================================================\n");
+ printk( "[ INFO: possible circular locking dependency detected ]\n");
+ print_kernel_version();
+ printk( "-------------------------------------------------------\n");
+ printk("%s/%d is trying to acquire lock:\n",
+ curr->comm, task_pid_nr(curr));
+ print_lock(check_source);
+ printk("\nbut task is already holding lock:\n");
+ print_lock(check_target);
+ printk("\nwhich lock already depends on the new lock.\n\n");
+ printk("\nthe existing dependency chain (in reverse order) is:\n");
+
+ print_circular_bug_entry(entry, depth);
+
+ return 0;
+}
+
+static noinline int print_circular_bug_tail(void)
+{
+ struct task_struct *curr = current;
+ struct lock_list this;
+
+ if (debug_locks_silent)
+ return 0;
+
+ this.class = check_source->class;
+ if (!save_trace(&this.trace))
+ return 0;
+
+ print_circular_bug_entry(&this, 0);
+
+ printk("\nother info that might help us debug this:\n\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+#define RECURSION_LIMIT 40
+
+static int noinline print_infinite_recursion_bug(void)
+{
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ WARN_ON(1);
+
+ return 0;
+}
+
+/*
+ * Prove that the dependency graph starting at <entry> can not
+ * lead to <target>. Print an error and return 0 if it does.
+ */
+static noinline int
+check_noncircular(struct lock_class *source, unsigned int depth)
+{
+ struct lock_list *entry;
+
+ debug_atomic_inc(&nr_cyclic_check_recursions);
+ if (depth > max_recursion_depth)
+ max_recursion_depth = depth;
+ if (depth >= RECURSION_LIMIT)
+ return print_infinite_recursion_bug();
+ /*
+ * Check this lock's dependency list:
+ */
+ list_for_each_entry(entry, &source->locks_after, entry) {
+ if (entry->class == check_target->class)
+ return print_circular_bug_header(entry, depth+1);
+ debug_atomic_inc(&nr_cyclic_checks);
+ if (!check_noncircular(entry->class, depth+1))
+ return print_circular_bug_entry(entry, depth+1);
+ }
+ return 1;
+}
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * Forwards and backwards subgraph searching, for the purposes of
+ * proving that two subgraphs can be connected by a new dependency
+ * without creating any illegal irq-safe -> irq-unsafe lock dependency.
+ */
+static enum lock_usage_bit find_usage_bit;
+static struct lock_class *forwards_match, *backwards_match;
+
+/*
+ * Find a node in the forwards-direction dependency sub-graph starting
+ * at <source> that matches <find_usage_bit>.
+ *
+ * Return 2 if such a node exists in the subgraph, and put that node
+ * into <forwards_match>.
+ *
+ * Return 1 otherwise and keep <forwards_match> unchanged.
+ * Return 0 on error.
+ */
+static noinline int
+find_usage_forwards(struct lock_class *source, unsigned int depth)
+{
+ struct lock_list *entry;
+ int ret;
+
+ if (depth > max_recursion_depth)
+ max_recursion_depth = depth;
+ if (depth >= RECURSION_LIMIT)
+ return print_infinite_recursion_bug();
+
+ debug_atomic_inc(&nr_find_usage_forwards_checks);
+ if (source->usage_mask & (1 << find_usage_bit)) {
+ forwards_match = source;
+ return 2;
+ }
+
+ /*
+ * Check this lock's dependency list:
+ */
+ list_for_each_entry(entry, &source->locks_after, entry) {
+ debug_atomic_inc(&nr_find_usage_forwards_recursions);
+ ret = find_usage_forwards(entry->class, depth+1);
+ if (ret == 2 || ret == 0)
+ return ret;
+ }
+ return 1;
+}
+
+/*
+ * Find a node in the backwards-direction dependency sub-graph starting
+ * at <source> that matches <find_usage_bit>.
+ *
+ * Return 2 if such a node exists in the subgraph, and put that node
+ * into <backwards_match>.
+ *
+ * Return 1 otherwise and keep <backwards_match> unchanged.
+ * Return 0 on error.
+ */
+static noinline int
+find_usage_backwards(struct lock_class *source, unsigned int depth)
+{
+ struct lock_list *entry;
+ int ret;
+
+ if (!__raw_spin_is_locked(&lockdep_lock))
+ return DEBUG_LOCKS_WARN_ON(1);
+
+ if (depth > max_recursion_depth)
+ max_recursion_depth = depth;
+ if (depth >= RECURSION_LIMIT)
+ return print_infinite_recursion_bug();
+
+ debug_atomic_inc(&nr_find_usage_backwards_checks);
+ if (source->usage_mask & (1 << find_usage_bit)) {
+ backwards_match = source;
+ return 2;
+ }
+
+ /*
+ * Check this lock's dependency list:
+ */
+ list_for_each_entry(entry, &source->locks_before, entry) {
+ debug_atomic_inc(&nr_find_usage_backwards_recursions);
+ ret = find_usage_backwards(entry->class, depth+1);
+ if (ret == 2 || ret == 0)
+ return ret;
+ }
+ return 1;
+}
+
+static int
+print_bad_irq_dependency(struct task_struct *curr,
+ struct held_lock *prev,
+ struct held_lock *next,
+ enum lock_usage_bit bit1,
+ enum lock_usage_bit bit2,
+ const char *irqclass)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n======================================================\n");
+ printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
+ irqclass, irqclass);
+ print_kernel_version();
+ printk( "------------------------------------------------------\n");
+ printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
+ curr->comm, task_pid_nr(curr),
+ curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
+ curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
+ curr->hardirqs_enabled,
+ curr->softirqs_enabled);
+ print_lock(next);
+
+ printk("\nand this task is already holding:\n");
+ print_lock(prev);
+ printk("which would create a new lock dependency:\n");
+ print_lock_name(prev->class);
+ printk(" ->");
+ print_lock_name(next->class);
+ printk("\n");
+
+ printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
+ irqclass);
+ print_lock_name(backwards_match);
+ printk("\n... which became %s-irq-safe at:\n", irqclass);
+
+ print_stack_trace(backwards_match->usage_traces + bit1, 1);
+
+ printk("\nto a %s-irq-unsafe lock:\n", irqclass);
+ print_lock_name(forwards_match);
+ printk("\n... which became %s-irq-unsafe at:\n", irqclass);
+ printk("...");
+
+ print_stack_trace(forwards_match->usage_traces + bit2, 1);
+
+ printk("\nother info that might help us debug this:\n\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass);
+ print_lock_dependencies(backwards_match, 0);
+
+ printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass);
+ print_lock_dependencies(forwards_match, 0);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static int
+check_usage(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next, enum lock_usage_bit bit_backwards,
+ enum lock_usage_bit bit_forwards, const char *irqclass)
+{
+ int ret;
+
+ find_usage_bit = bit_backwards;
+ /* fills in <backwards_match> */
+ ret = find_usage_backwards(prev->class, 0);
+ if (!ret || ret == 1)
+ return ret;
+
+ find_usage_bit = bit_forwards;
+ ret = find_usage_forwards(next->class, 0);
+ if (!ret || ret == 1)
+ return ret;
+ /* ret == 2 */
+ return print_bad_irq_dependency(curr, prev, next,
+ bit_backwards, bit_forwards, irqclass);
+}
+
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ /*
+ * Prove that the new dependency does not connect a hardirq-safe
+ * lock with a hardirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
+ LOCK_ENABLED_HARDIRQS, "hard"))
+ return 0;
+
+ /*
+ * Prove that the new dependency does not connect a hardirq-safe-read
+ * lock with a hardirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
+ LOCK_ENABLED_HARDIRQS, "hard-read"))
+ return 0;
+
+ /*
+ * Prove that the new dependency does not connect a softirq-safe
+ * lock with a softirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
+ LOCK_ENABLED_SOFTIRQS, "soft"))
+ return 0;
+ /*
+ * Prove that the new dependency does not connect a softirq-safe-read
+ * lock with a softirq-unsafe lock - to achieve this we search
+ * the backwards-subgraph starting at <prev>, and the
+ * forwards-subgraph starting at <next>:
+ */
+ if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
+ LOCK_ENABLED_SOFTIRQS, "soft"))
+ return 0;
+
+ return 1;
+}
+
+static void inc_chains(void)
+{
+ if (current->hardirq_context)
+ nr_hardirq_chains++;
+ else {
+ if (current->softirq_context)
+ nr_softirq_chains++;
+ else
+ nr_process_chains++;
+ }
+}
+
+#else
+
+static inline int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ return 1;
+}
+
+static inline void inc_chains(void)
+{
+ nr_process_chains++;
+}
+
+#endif
+
+static int
+print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n=============================================\n");
+ printk( "[ INFO: possible recursive locking detected ]\n");
+ print_kernel_version();
+ printk( "---------------------------------------------\n");
+ printk("%s/%d is trying to acquire lock:\n",
+ curr->comm, task_pid_nr(curr));
+ print_lock(next);
+ printk("\nbut task is already holding lock:\n");
+ print_lock(prev);
+
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Check whether we are holding such a class already.
+ *
+ * (Note that this has to be done separately, because the graph cannot
+ * detect such classes of deadlocks.)
+ *
+ * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
+ */
+static int
+check_deadlock(struct task_struct *curr, struct held_lock *next,
+ struct lockdep_map *next_instance, int read)
+{
+ struct held_lock *prev;
+ int i;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ prev = curr->held_locks + i;
+ if (prev->class != next->class)
+ continue;
+ /*
+ * Allow read-after-read recursion of the same
+ * lock class (i.e. read_lock(lock)+read_lock(lock)):
+ */
+ if ((read == 2) && prev->read)
+ return 2;
+ return print_deadlock_bug(curr, prev, next);
+ }
+ return 1;
+}
+
+/*
+ * There was a chain-cache miss, and we are about to add a new dependency
+ * to a previous lock. We recursively validate the following rules:
+ *
+ * - would the adding of the <prev> -> <next> dependency create a
+ * circular dependency in the graph? [== circular deadlock]
+ *
+ * - does the new prev->next dependency connect any hardirq-safe lock
+ * (in the full backwards-subgraph starting at <prev>) with any
+ * hardirq-unsafe lock (in the full forwards-subgraph starting at
+ * <next>)? [== illegal lock inversion with hardirq contexts]
+ *
+ * - does the new prev->next dependency connect any softirq-safe lock
+ * (in the full backwards-subgraph starting at <prev>) with any
+ * softirq-unsafe lock (in the full forwards-subgraph starting at
+ * <next>)? [== illegal lock inversion with softirq contexts]
+ *
+ * any of these scenarios could lead to a deadlock.
+ *
+ * Then if all the validations pass, we add the forwards and backwards
+ * dependency.
+ */
+static int
+check_prev_add(struct task_struct *curr, struct held_lock *prev,
+ struct held_lock *next, int distance)
+{
+ struct lock_list *entry;
+ int ret;
+
+ /*
+ * Prove that the new <prev> -> <next> dependency would not
+ * create a circular dependency in the graph. (We do this by
+ * forward-recursing into the graph starting at <next>, and
+ * checking whether we can reach <prev>.)
+ *
+ * We are using global variables to control the recursion, to
+ * keep the stackframe size of the recursive functions low:
+ */
+ check_source = next;
+ check_target = prev;
+ if (!(check_noncircular(next->class, 0)))
+ return print_circular_bug_tail();
+
+ if (!check_prev_add_irq(curr, prev, next))
+ return 0;
+
+ /*
+ * For recursive read-locks we do all the dependency checks,
+ * but we dont store read-triggered dependencies (only
+ * write-triggered dependencies). This ensures that only the
+ * write-side dependencies matter, and that if for example a
+ * write-lock never takes any other locks, then the reads are
+ * equivalent to a NOP.
+ */
+ if (next->read == 2 || prev->read == 2)
+ return 1;
+ /*
+ * Is the <prev> -> <next> dependency already present?
+ *
+ * (this may occur even though this is a new chain: consider
+ * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
+ * chains - the second one will be new, but L1 already has
+ * L2 added to its dependency list, due to the first chain.)
+ */
+ list_for_each_entry(entry, &prev->class->locks_after, entry) {
+ if (entry->class == next->class) {
+ if (distance == 1)
+ entry->distance = 1;
+ return 2;
+ }
+ }
+
+ /*
+ * Ok, all validations passed, add the new lock
+ * to the previous lock's dependency list:
+ */
+ ret = add_lock_to_list(prev->class, next->class,
+ &prev->class->locks_after, next->acquire_ip, distance);
+
+ if (!ret)
+ return 0;
+
+ ret = add_lock_to_list(next->class, prev->class,
+ &next->class->locks_before, next->acquire_ip, distance);
+ if (!ret)
+ return 0;
+
+ /*
+ * Debugging printouts:
+ */
+ if (verbose(prev->class) || verbose(next->class)) {
+ graph_unlock();
+ printk("\n new dependency: ");
+ print_lock_name(prev->class);
+ printk(" => ");
+ print_lock_name(next->class);
+ printk("\n");
+ dump_stack();
+ return graph_lock();
+ }
+ return 1;
+}
+
+/*
+ * Add the dependency to all directly-previous locks that are 'relevant'.
+ * The ones that are relevant are (in increasing distance from curr):
+ * all consecutive trylock entries and the final non-trylock entry - or
+ * the end of this context's lock-chain - whichever comes first.
+ */
+static int
+check_prevs_add(struct task_struct *curr, struct held_lock *next)
+{
+ int depth = curr->lockdep_depth;
+ struct held_lock *hlock;
+
+ /*
+ * Debugging checks.
+ *
+ * Depth must not be zero for a non-head lock:
+ */
+ if (!depth)
+ goto out_bug;
+ /*
+ * At least two relevant locks must exist for this
+ * to be a head:
+ */
+ if (curr->held_locks[depth].irq_context !=
+ curr->held_locks[depth-1].irq_context)
+ goto out_bug;
+
+ for (;;) {
+ int distance = curr->lockdep_depth - depth + 1;
+ hlock = curr->held_locks + depth-1;
+ /*
+ * Only non-recursive-read entries get new dependencies
+ * added:
+ */
+ if (hlock->read != 2) {
+ if (!check_prev_add(curr, hlock, next, distance))
+ return 0;
+ /*
+ * Stop after the first non-trylock entry,
+ * as non-trylock entries have added their
+ * own direct dependencies already, so this
+ * lock is connected to them indirectly:
+ */
+ if (!hlock->trylock)
+ break;
+ }
+ depth--;
+ /*
+ * End of lock-stack?
+ */
+ if (!depth)
+ break;
+ /*
+ * Stop the search if we cross into another context:
+ */
+ if (curr->held_locks[depth].irq_context !=
+ curr->held_locks[depth-1].irq_context)
+ break;
+ }
+ return 1;
+out_bug:
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ WARN_ON(1);
+
+ return 0;
+}
+
+unsigned long nr_lock_chains;
+static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
+
+/*
+ * Look up a dependency chain. If the key is not present yet then
+ * add it and return 1 - in this case the new dependency chain is
+ * validated. If the key is already hashed, return 0.
+ * (On return with 1 graph_lock is held.)
+ */
+static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
+{
+ struct list_head *hash_head = chainhashentry(chain_key);
+ struct lock_chain *chain;
+
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+ /*
+ * We can walk it lock-free, because entries only get added
+ * to the hash:
+ */
+ list_for_each_entry(chain, hash_head, entry) {
+ if (chain->chain_key == chain_key) {
+cache_hit:
+ debug_atomic_inc(&chain_lookup_hits);
+ if (very_verbose(class))
+ printk("\nhash chain already cached, key: "
+ "%016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key,
+ class->key, class->name);
+ return 0;
+ }
+ }
+ if (very_verbose(class))
+ printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
+ (unsigned long long)chain_key, class->key, class->name);
+ /*
+ * Allocate a new chain entry from the static array, and add
+ * it to the hash:
+ */
+ if (!graph_lock())
+ return 0;
+ /*
+ * We have to walk the chain again locked - to avoid duplicates:
+ */
+ list_for_each_entry(chain, hash_head, entry) {
+ if (chain->chain_key == chain_key) {
+ graph_unlock();
+ goto cache_hit;
+ }
+ }
+ if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+
+ printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ return 0;
+ }
+ chain = lock_chains + nr_lock_chains++;
+ chain->chain_key = chain_key;
+ list_add_tail_rcu(&chain->entry, hash_head);
+ debug_atomic_inc(&chain_lookup_misses);
+ inc_chains();
+
+ return 1;
+}
+
+static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
+ struct held_lock *hlock, int chain_head, u64 chain_key)
+{
+ /*
+ * Trylock needs to maintain the stack of held locks, but it
+ * does not add new dependencies, because trylock can be done
+ * in any order.
+ *
+ * We look up the chain_key and do the O(N^2) check and update of
+ * the dependencies only if this is a new dependency chain.
+ * (If lookup_chain_cache() returns with 1 it acquires
+ * graph_lock for us)
+ */
+ if (!hlock->trylock && (hlock->check == 2) &&
+ lookup_chain_cache(chain_key, hlock->class)) {
+ /*
+ * Check whether last held lock:
+ *
+ * - is irq-safe, if this lock is irq-unsafe
+ * - is softirq-safe, if this lock is hardirq-unsafe
+ *
+ * And check whether the new lock's dependency graph
+ * could lead back to the previous lock.
+ *
+ * any of these scenarios could lead to a deadlock. If
+ * All validations
+ */
+ int ret = check_deadlock(curr, hlock, lock, hlock->read);
+
+ if (!ret)
+ return 0;
+ /*
+ * Mark recursive read, as we jump over it when
+ * building dependencies (just like we jump over
+ * trylock entries):
+ */
+ if (ret == 2)
+ hlock->read = 2;
+ /*
+ * Add dependency only if this lock is not the head
+ * of the chain, and if it's not a secondary read-lock:
+ */
+ if (!chain_head && ret != 2)
+ if (!check_prevs_add(curr, hlock))
+ return 0;
+ graph_unlock();
+ } else
+ /* after lookup_chain_cache(): */
+ if (unlikely(!debug_locks))
+ return 0;
+
+ return 1;
+}
+#else
+static inline int validate_chain(struct task_struct *curr,
+ struct lockdep_map *lock, struct held_lock *hlock,
+ int chain_head, u64 chain_key)
+{
+ return 1;
+}
+#endif
+
+/*
+ * We are building curr_chain_key incrementally, so double-check
+ * it from scratch, to make sure that it's done correctly:
+ */
+static void check_chain_key(struct task_struct *curr)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+ struct held_lock *hlock, *prev_hlock = NULL;
+ unsigned int i, id;
+ u64 chain_key = 0;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ hlock = curr->held_locks + i;
+ if (chain_key != hlock->prev_chain_key) {
+ debug_locks_off();
+ printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n",
+ curr->lockdep_depth, i,
+ (unsigned long long)chain_key,
+ (unsigned long long)hlock->prev_chain_key);
+ WARN_ON(1);
+ return;
+ }
+ id = hlock->class - lock_classes;
+ if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+ return;
+
+ if (prev_hlock && (prev_hlock->irq_context !=
+ hlock->irq_context))
+ chain_key = 0;
+ chain_key = iterate_chain_key(chain_key, id);
+ prev_hlock = hlock;
+ }
+ if (chain_key != curr->curr_chain_key) {
+ debug_locks_off();
+ printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n",
+ curr->lockdep_depth, i,
+ (unsigned long long)chain_key,
+ (unsigned long long)curr->curr_chain_key);
+ WARN_ON(1);
+ }
+#endif
+}
+
+static int
+print_usage_bug(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n=================================\n");
+ printk( "[ INFO: inconsistent lock state ]\n");
+ print_kernel_version();
+ printk( "---------------------------------\n");
+
+ printk("inconsistent {%s} -> {%s} usage.\n",
+ usage_str[prev_bit], usage_str[new_bit]);
+
+ printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
+ curr->comm, task_pid_nr(curr),
+ trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
+ trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
+ trace_hardirqs_enabled(curr),
+ trace_softirqs_enabled(curr));
+ print_lock(this);
+
+ printk("{%s} state was registered at:\n", usage_str[prev_bit]);
+ print_stack_trace(this->class->usage_traces + prev_bit, 1);
+
+ print_irqtrace_events(curr);
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Print out an error if an invalid bit is set:
+ */
+static inline int
+valid_state(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+{
+ if (unlikely(this->class->usage_mask & (1 << bad_bit)))
+ return print_usage_bug(curr, this, bad_bit, new_bit);
+ return 1;
+}
+
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit);
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+
+/*
+ * print irq inversion bug:
+ */
+static int
+print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
+ struct held_lock *this, int forwards,
+ const char *irqclass)
+{
+ if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+ return 0;
+
+ printk("\n=========================================================\n");
+ printk( "[ INFO: possible irq lock inversion dependency detected ]\n");
+ print_kernel_version();
+ printk( "---------------------------------------------------------\n");
+ printk("%s/%d just changed the state of lock:\n",
+ curr->comm, task_pid_nr(curr));
+ print_lock(this);
+ if (forwards)
+ printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
+ else
+ printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
+ print_lock_name(other);
+ printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
+
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nthe first lock's dependencies:\n");
+ print_lock_dependencies(this->class, 0);
+
+ printk("\nthe second lock's dependencies:\n");
+ print_lock_dependencies(other, 0);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Prove that in the forwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_forwards(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit bit, const char *irqclass)
+{
+ int ret;
+
+ find_usage_bit = bit;
+ /* fills in <forwards_match> */
+ ret = find_usage_forwards(this->class, 0);
+ if (!ret || ret == 1)
+ return ret;
+
+ return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass);
+}
+
+/*
+ * Prove that in the backwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_backwards(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit bit, const char *irqclass)
+{
+ int ret;
+
+ find_usage_bit = bit;
+ /* fills in <backwards_match> */
+ ret = find_usage_backwards(this->class, 0);
+ if (!ret || ret == 1)
+ return ret;
+
+ return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
+}
+
+void print_irqtrace_events(struct task_struct *curr)
+{
+ printk("irq event stamp: %u\n", curr->irq_events);
+ printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
+ print_ip_sym(curr->hardirq_enable_ip);
+ printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
+ print_ip_sym(curr->hardirq_disable_ip);
+ printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
+ print_ip_sym(curr->softirq_enable_ip);
+ printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
+ print_ip_sym(curr->softirq_disable_ip);
+}
+
+static int hardirq_verbose(struct lock_class *class)
+{
+#if HARDIRQ_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+static int softirq_verbose(struct lock_class *class)
+{
+#if SOFTIRQ_VERBOSE
+ return class_filter(class);
+#endif
+ return 0;
+}
+
+#define STRICT_READ_CHECKS 1
+
+static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ int ret = 1;
+
+ switch(new_bit) {
+ case LOCK_USED_IN_HARDIRQ:
+ if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
+ return 0;
+ if (!valid_state(curr, this, new_bit,
+ LOCK_ENABLED_HARDIRQS_READ))
+ return 0;
+ /*
+ * just marked it hardirq-safe, check that this lock
+ * took no hardirq-unsafe lock in the past:
+ */
+ if (!check_usage_forwards(curr, this,
+ LOCK_ENABLED_HARDIRQS, "hard"))
+ return 0;
+#if STRICT_READ_CHECKS
+ /*
+ * just marked it hardirq-safe, check that this lock
+ * took no hardirq-unsafe-read lock in the past:
+ */
+ if (!check_usage_forwards(curr, this,
+ LOCK_ENABLED_HARDIRQS_READ, "hard-read"))
+ return 0;
+#endif
+ if (hardirq_verbose(this->class))
+ ret = 2;
+ break;
+ case LOCK_USED_IN_SOFTIRQ:
+ if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
+ return 0;
+ if (!valid_state(curr, this, new_bit,
+ LOCK_ENABLED_SOFTIRQS_READ))
+ return 0;
+ /*
+ * just marked it softirq-safe, check that this lock
+ * took no softirq-unsafe lock in the past:
+ */
+ if (!check_usage_forwards(curr, this,
+ LOCK_ENABLED_SOFTIRQS, "soft"))
+ return 0;
+#if STRICT_READ_CHECKS
+ /*
+ * just marked it softirq-safe, check that this lock
+ * took no softirq-unsafe-read lock in the past:
+ */
+ if (!check_usage_forwards(curr, this,
+ LOCK_ENABLED_SOFTIRQS_READ, "soft-read"))
+ return 0;
+#endif
+ if (softirq_verbose(this->class))
+ ret = 2;
+ break;
+ case LOCK_USED_IN_HARDIRQ_READ:
+ if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
+ return 0;
+ /*
+ * just marked it hardirq-read-safe, check that this lock
+ * took no hardirq-unsafe lock in the past:
+ */
+ if (!check_usage_forwards(curr, this,
+ LOCK_ENABLED_HARDIRQS, "hard"))
+ return 0;
+ if (hardirq_verbose(this->class))
+ ret = 2;
+ break;
+ case LOCK_USED_IN_SOFTIRQ_READ:
+ if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
+ return 0;
+ /*
+ * just marked it softirq-read-safe, check that this lock
+ * took no softirq-unsafe lock in the past:
+ */
+ if (!check_usage_forwards(curr, this,
+ LOCK_ENABLED_SOFTIRQS, "soft"))
+ return 0;
+ if (softirq_verbose(this->class))
+ ret = 2;
+ break;
+ case LOCK_ENABLED_HARDIRQS:
+ if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
+ return 0;
+ if (!valid_state(curr, this, new_bit,
+ LOCK_USED_IN_HARDIRQ_READ))
+ return 0;
+ /*
+ * just marked it hardirq-unsafe, check that no hardirq-safe
+ * lock in the system ever took it in the past:
+ */
+ if (!check_usage_backwards(curr, this,
+ LOCK_USED_IN_HARDIRQ, "hard"))
+ return 0;
+#if STRICT_READ_CHECKS
+ /*
+ * just marked it hardirq-unsafe, check that no
+ * hardirq-safe-read lock in the system ever took
+ * it in the past:
+ */
+ if (!check_usage_backwards(curr, this,
+ LOCK_USED_IN_HARDIRQ_READ, "hard-read"))
+ return 0;
+#endif
+ if (hardirq_verbose(this->class))
+ ret = 2;
+ break;
+ case LOCK_ENABLED_SOFTIRQS:
+ if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
+ return 0;
+ if (!valid_state(curr, this, new_bit,
+ LOCK_USED_IN_SOFTIRQ_READ))
+ return 0;
+ /*
+ * just marked it softirq-unsafe, check that no softirq-safe
+ * lock in the system ever took it in the past:
+ */
+ if (!check_usage_backwards(curr, this,
+ LOCK_USED_IN_SOFTIRQ, "soft"))
+ return 0;
+#if STRICT_READ_CHECKS
+ /*
+ * just marked it softirq-unsafe, check that no
+ * softirq-safe-read lock in the system ever took
+ * it in the past:
+ */
+ if (!check_usage_backwards(curr, this,
+ LOCK_USED_IN_SOFTIRQ_READ, "soft-read"))
+ return 0;
+#endif
+ if (softirq_verbose(this->class))
+ ret = 2;
+ break;
+ case LOCK_ENABLED_HARDIRQS_READ:
+ if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
+ return 0;
+#if STRICT_READ_CHECKS
+ /*
+ * just marked it hardirq-read-unsafe, check that no
+ * hardirq-safe lock in the system ever took it in the past:
+ */
+ if (!check_usage_backwards(curr, this,
+ LOCK_USED_IN_HARDIRQ, "hard"))
+ return 0;
+#endif
+ if (hardirq_verbose(this->class))
+ ret = 2;
+ break;
+ case LOCK_ENABLED_SOFTIRQS_READ:
+ if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
+ return 0;
+#if STRICT_READ_CHECKS
+ /*
+ * just marked it softirq-read-unsafe, check that no
+ * softirq-safe lock in the system ever took it in the past:
+ */
+ if (!check_usage_backwards(curr, this,
+ LOCK_USED_IN_SOFTIRQ, "soft"))
+ return 0;
+#endif
+ if (softirq_verbose(this->class))
+ ret = 2;
+ break;
+ default:
+ WARN_ON(1);
+ break;
+ }
+
+ return ret;
+}
+
+/*
+ * Mark all held locks with a usage bit:
+ */
+static int
+mark_held_locks(struct task_struct *curr, int hardirq)
+{
+ enum lock_usage_bit usage_bit;
+ struct held_lock *hlock;
+ int i;
+
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ hlock = curr->held_locks + i;
+
+ if (hardirq) {
+ if (hlock->read)
+ usage_bit = LOCK_ENABLED_HARDIRQS_READ;
+ else
+ usage_bit = LOCK_ENABLED_HARDIRQS;
+ } else {
+ if (hlock->read)
+ usage_bit = LOCK_ENABLED_SOFTIRQS_READ;
+ else
+ usage_bit = LOCK_ENABLED_SOFTIRQS;
+ }
+ if (!mark_lock(curr, hlock, usage_bit))
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Debugging helper: via this flag we know that we are in
+ * 'early bootup code', and will warn about any invalid irqs-on event:
+ */
+static int early_boot_irqs_enabled;
+
+void early_boot_irqs_off(void)
+{
+ early_boot_irqs_enabled = 0;
+}
+
+void early_boot_irqs_on(void)
+{
+ early_boot_irqs_enabled = 1;
+}
+
+/*
+ * Hardirqs will be enabled:
+ */
+void trace_hardirqs_on(void)
+{
+ struct task_struct *curr = current;
+ unsigned long ip;
+
+ if (unlikely(!debug_locks || current->lockdep_recursion))
+ return;
+
+ if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
+ return;
+
+ if (unlikely(curr->hardirqs_enabled)) {
+ debug_atomic_inc(&redundant_hardirqs_on);
+ return;
+ }
+ /* we'll do an OFF -> ON transition: */
+ curr->hardirqs_enabled = 1;
+ ip = (unsigned long) __builtin_return_address(0);
+
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+ if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
+ return;
+ /*
+ * We are going to turn hardirqs on, so set the
+ * usage bit for all held locks:
+ */
+ if (!mark_held_locks(curr, 1))
+ return;
+ /*
+ * If we have softirqs enabled, then set the usage
+ * bit for all held locks. (disabled hardirqs prevented
+ * this bit from being set before)
+ */
+ if (curr->softirqs_enabled)
+ if (!mark_held_locks(curr, 0))
+ return;
+
+ curr->hardirq_enable_ip = ip;
+ curr->hardirq_enable_event = ++curr->irq_events;
+ debug_atomic_inc(&hardirqs_on_events);
+}
+
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+/*
+ * Hardirqs were disabled:
+ */
+void trace_hardirqs_off(void)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(!debug_locks || current->lockdep_recursion))
+ return;
+
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ if (curr->hardirqs_enabled) {
+ /*
+ * We have done an ON -> OFF transition:
+ */
+ curr->hardirqs_enabled = 0;
+ curr->hardirq_disable_ip = _RET_IP_;
+ curr->hardirq_disable_event = ++curr->irq_events;
+ debug_atomic_inc(&hardirqs_off_events);
+ } else
+ debug_atomic_inc(&redundant_hardirqs_off);
+}
+
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+/*
+ * Softirqs will be enabled:
+ */
+void trace_softirqs_on(unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(!debug_locks))
+ return;
+
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ if (curr->softirqs_enabled) {
+ debug_atomic_inc(&redundant_softirqs_on);
+ return;
+ }
+
+ /*
+ * We'll do an OFF -> ON transition:
+ */
+ curr->softirqs_enabled = 1;
+ curr->softirq_enable_ip = ip;
+ curr->softirq_enable_event = ++curr->irq_events;
+ debug_atomic_inc(&softirqs_on_events);
+ /*
+ * We are going to turn softirqs on, so set the
+ * usage bit for all held locks, if hardirqs are
+ * enabled too:
+ */
+ if (curr->hardirqs_enabled)
+ mark_held_locks(curr, 0);
+}
+
+/*
+ * Softirqs were disabled:
+ */
+void trace_softirqs_off(unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(!debug_locks))
+ return;
+
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return;
+
+ if (curr->softirqs_enabled) {
+ /*
+ * We have done an ON -> OFF transition:
+ */
+ curr->softirqs_enabled = 0;
+ curr->softirq_disable_ip = ip;
+ curr->softirq_disable_event = ++curr->irq_events;
+ debug_atomic_inc(&softirqs_off_events);
+ DEBUG_LOCKS_WARN_ON(!softirq_count());
+ } else
+ debug_atomic_inc(&redundant_softirqs_off);
+}
+
+static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
+{
+ /*
+ * If non-trylock use in a hardirq or softirq context, then
+ * mark the lock as used in these contexts:
+ */
+ if (!hlock->trylock) {
+ if (hlock->read) {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_HARDIRQ_READ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock,
+ LOCK_USED_IN_SOFTIRQ_READ))
+ return 0;
+ } else {
+ if (curr->hardirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
+ return 0;
+ if (curr->softirq_context)
+ if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
+ return 0;
+ }
+ }
+ if (!hlock->hardirqs_off) {
+ if (hlock->read) {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQS_READ))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_SOFTIRQS_READ))
+ return 0;
+ } else {
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_HARDIRQS))
+ return 0;
+ if (curr->softirqs_enabled)
+ if (!mark_lock(curr, hlock,
+ LOCK_ENABLED_SOFTIRQS))
+ return 0;
+ }
+ }
+
+ return 1;
+}
+
+static int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ unsigned int depth = curr->lockdep_depth;
+
+ /*
+ * Keep track of points where we cross into an interrupt context:
+ */
+ hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
+ curr->softirq_context;
+ if (depth) {
+ struct held_lock *prev_hlock;
+
+ prev_hlock = curr->held_locks + depth-1;
+ /*
+ * If we cross into another context, reset the
+ * hash key (this also prevents the checking and the
+ * adding of the dependency to 'prev'):
+ */
+ if (prev_hlock->irq_context != hlock->irq_context)
+ return 1;
+ }
+ return 0;
+}
+
+#else
+
+static inline
+int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ WARN_ON(1);
+ return 1;
+}
+
+static inline int mark_irqflags(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 1;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+ struct held_lock *hlock)
+{
+ return 0;
+}
+
+#endif
+
+/*
+ * Mark a lock with a usage bit, and validate the state transition:
+ */
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+ enum lock_usage_bit new_bit)
+{
+ unsigned int new_mask = 1 << new_bit, ret = 1;
+
+ /*
+ * If already set then do not dirty the cacheline,
+ * nor do any checks:
+ */
+ if (likely(this->class->usage_mask & new_mask))
+ return 1;
+
+ if (!graph_lock())
+ return 0;
+ /*
+ * Make sure we didnt race:
+ */
+ if (unlikely(this->class->usage_mask & new_mask)) {
+ graph_unlock();
+ return 1;
+ }
+
+ this->class->usage_mask |= new_mask;
+
+ if (!save_trace(this->class->usage_traces + new_bit))
+ return 0;
+
+ switch (new_bit) {
+ case LOCK_USED_IN_HARDIRQ:
+ case LOCK_USED_IN_SOFTIRQ:
+ case LOCK_USED_IN_HARDIRQ_READ:
+ case LOCK_USED_IN_SOFTIRQ_READ:
+ case LOCK_ENABLED_HARDIRQS:
+ case LOCK_ENABLED_SOFTIRQS:
+ case LOCK_ENABLED_HARDIRQS_READ:
+ case LOCK_ENABLED_SOFTIRQS_READ:
+ ret = mark_lock_irq(curr, this, new_bit);
+ if (!ret)
+ return 0;
+ break;
+ case LOCK_USED:
+ /*
+ * Add it to the global list of classes:
+ */
+ list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes);
+ debug_atomic_dec(&nr_unused_locks);
+ break;
+ default:
+ if (!debug_locks_off_graph_unlock())
+ return 0;
+ WARN_ON(1);
+ return 0;
+ }
+
+ graph_unlock();
+
+ /*
+ * We must printk outside of the graph_lock:
+ */
+ if (ret == 2) {
+ printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+ print_lock(this);
+ print_irqtrace_events(curr);
+ dump_stack();
+ }
+
+ return ret;
+}
+
+/*
+ * Initialize a lock instance's lock-class mapping info:
+ */
+void lockdep_init_map(struct lockdep_map *lock, const char *name,
+ struct lock_class_key *key, int subclass)
+{
+ if (unlikely(!debug_locks))
+ return;
+
+ if (DEBUG_LOCKS_WARN_ON(!key))
+ return;
+ if (DEBUG_LOCKS_WARN_ON(!name))
+ return;
+ /*
+ * Sanity check, the lock-class key must be persistent:
+ */
+ if (!static_obj(key)) {
+ printk("BUG: key %p not in .data!\n", key);
+ DEBUG_LOCKS_WARN_ON(1);
+ return;
+ }
+ lock->name = name;
+ lock->key = key;
+ lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+ lock->cpu = raw_smp_processor_id();
+#endif
+ if (subclass)
+ register_lock_class(lock, subclass, 1);
+}
+
+EXPORT_SYMBOL_GPL(lockdep_init_map);
+
+/*
+ * This gets called for every mutex_lock*()/spin_lock*() operation.
+ * We maintain the dependency maps and validate the locking attempt:
+ */
+static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+ int trylock, int read, int check, int hardirqs_off,
+ unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct lock_class *class = NULL;
+ struct held_lock *hlock;
+ unsigned int depth, id;
+ int chain_head = 0;
+ u64 chain_key;
+
+ if (!prove_locking)
+ check = 1;
+
+ if (unlikely(!debug_locks))
+ return 0;
+
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+
+ if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
+ debug_locks_off();
+ printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ return 0;
+ }
+
+ if (!subclass)
+ class = lock->class_cache;
+ /*
+ * Not cached yet or subclass?
+ */
+ if (unlikely(!class)) {
+ class = register_lock_class(lock, subclass, 0);
+ if (!class)
+ return 0;
+ }
+ debug_atomic_inc((atomic_t *)&class->ops);
+ if (very_verbose(class)) {
+ printk("\nacquire class [%p] %s", class->key, class->name);
+ if (class->name_version > 1)
+ printk("#%d", class->name_version);
+ printk("\n");
+ dump_stack();
+ }
+
+ /*
+ * Add the lock to the list of currently held locks.
+ * (we dont increase the depth just yet, up until the
+ * dependency checks are done)
+ */
+ depth = curr->lockdep_depth;
+ if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
+ return 0;
+
+ hlock = curr->held_locks + depth;
+
+ hlock->class = class;
+ hlock->acquire_ip = ip;
+ hlock->instance = lock;
+ hlock->trylock = trylock;
+ hlock->read = read;
+ hlock->check = check;
+ hlock->hardirqs_off = hardirqs_off;
+#ifdef CONFIG_LOCK_STAT
+ hlock->waittime_stamp = 0;
+ hlock->holdtime_stamp = sched_clock();
+#endif
+
+ if (check == 2 && !mark_irqflags(curr, hlock))
+ return 0;
+
+ /* mark it as used: */
+ if (!mark_lock(curr, hlock, LOCK_USED))
+ return 0;
+
+ /*
+ * Calculate the chain hash: it's the combined has of all the
+ * lock keys along the dependency chain. We save the hash value
+ * at every step so that we can get the current hash easily
+ * after unlock. The chain hash is then used to cache dependency
+ * results.
+ *
+ * The 'key ID' is what is the most compact key value to drive
+ * the hash, not class->key.
+ */
+ id = class - lock_classes;
+ if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+ return 0;
+
+ chain_key = curr->curr_chain_key;
+ if (!depth) {
+ if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
+ return 0;
+ chain_head = 1;
+ }
+
+ hlock->prev_chain_key = chain_key;
+ if (separate_irq_context(curr, hlock)) {
+ chain_key = 0;
+ chain_head = 1;
+ }
+ chain_key = iterate_chain_key(chain_key, id);
+
+ if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
+ return 0;
+
+ curr->curr_chain_key = chain_key;
+ curr->lockdep_depth++;
+ check_chain_key(curr);
+#ifdef CONFIG_DEBUG_LOCKDEP
+ if (unlikely(!debug_locks))
+ return 0;
+#endif
+ if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
+ debug_locks_off();
+ printk("BUG: MAX_LOCK_DEPTH too low!\n");
+ printk("turning off the locking correctness validator.\n");
+ return 0;
+ }
+
+ if (unlikely(curr->lockdep_depth > max_lockdep_depth))
+ max_lockdep_depth = curr->lockdep_depth;
+
+ return 1;
+}
+
+static int
+print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
+ unsigned long ip)
+{
+ if (!debug_locks_off())
+ return 0;
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n=====================================\n");
+ printk( "[ BUG: bad unlock balance detected! ]\n");
+ printk( "-------------------------------------\n");
+ printk("%s/%d is trying to release lock (",
+ curr->comm, task_pid_nr(curr));
+ print_lockdep_cache(lock);
+ printk(") at:\n");
+ print_ip_sym(ip);
+ printk("but there are no more locks to release!\n");
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+/*
+ * Common debugging checks for both nested and non-nested unlock:
+ */
+static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
+ unsigned long ip)
+{
+ if (unlikely(!debug_locks))
+ return 0;
+ if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+ return 0;
+
+ if (curr->lockdep_depth <= 0)
+ return print_unlock_inbalance_bug(curr, lock, ip);
+
+ return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks in a
+ * potentially non-nested (out of order) manner. This is a
+ * relatively rare operation, as all the unlock APIs default
+ * to nested mode (which uses lock_release()):
+ */
+static int
+lock_release_non_nested(struct task_struct *curr,
+ struct lockdep_map *lock, unsigned long ip)
+{
+ struct held_lock *hlock, *prev_hlock;
+ unsigned int depth;
+ int i;
+
+ /*
+ * Check whether the lock exists in the current stack
+ * of held locks:
+ */
+ depth = curr->lockdep_depth;
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return 0;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (hlock->instance == lock)
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ return print_unlock_inbalance_bug(curr, lock, ip);
+
+found_it:
+ lock_release_holdtime(hlock);
+
+ /*
+ * We have the right lock to unlock, 'hlock' points to it.
+ * Now we remove it from the stack, and add back the other
+ * entries (if any), recalculating the hash along the way:
+ */
+ curr->lockdep_depth = i;
+ curr->curr_chain_key = hlock->prev_chain_key;
+
+ for (i++; i < depth; i++) {
+ hlock = curr->held_locks + i;
+ if (!__lock_acquire(hlock->instance,
+ hlock->class->subclass, hlock->trylock,
+ hlock->read, hlock->check, hlock->hardirqs_off,
+ hlock->acquire_ip))
+ return 0;
+ }
+
+ if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
+ return 0;
+ return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()). This is done for unlocks that nest
+ * perfectly. (i.e. the current top of the lock-stack is unlocked)
+ */
+static int lock_release_nested(struct task_struct *curr,
+ struct lockdep_map *lock, unsigned long ip)
+{
+ struct held_lock *hlock;
+ unsigned int depth;
+
+ /*
+ * Pop off the top of the lock stack:
+ */
+ depth = curr->lockdep_depth - 1;
+ hlock = curr->held_locks + depth;
+
+ /*
+ * Is the unlock non-nested:
+ */
+ if (hlock->instance != lock)
+ return lock_release_non_nested(curr, lock, ip);
+ curr->lockdep_depth--;
+
+ if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
+ return 0;
+
+ curr->curr_chain_key = hlock->prev_chain_key;
+
+ lock_release_holdtime(hlock);
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ hlock->prev_chain_key = 0;
+ hlock->class = NULL;
+ hlock->acquire_ip = 0;
+ hlock->irq_context = 0;
+#endif
+ return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()). This is done for unlocks that nest
+ * perfectly. (i.e. the current top of the lock-stack is unlocked)
+ */
+static void
+__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+{
+ struct task_struct *curr = current;
+
+ if (!check_unlock(curr, lock, ip))
+ return;
+
+ if (nested) {
+ if (!lock_release_nested(curr, lock, ip))
+ return;
+ } else {
+ if (!lock_release_non_nested(curr, lock, ip))
+ return;
+ }
+
+ check_chain_key(curr);
+}
+
+/*
+ * Check whether we follow the irq-flags state precisely:
+ */
+static void check_flags(unsigned long flags)
+{
+#if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS)
+ if (!debug_locks)
+ return;
+
+ if (irqs_disabled_flags(flags))
+ DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled);
+ else
+ DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled);
+
+ /*
+ * We dont accurately track softirq state in e.g.
+ * hardirq contexts (such as on 4KSTACKS), so only
+ * check if not in hardirq contexts:
+ */
+ if (!hardirq_count()) {
+ if (softirq_count())
+ DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
+ else
+ DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
+ }
+
+ if (!debug_locks)
+ print_irqtrace_events(current);
+#endif
+}
+
+/*
+ * We are not always called with irqs disabled - do that here,
+ * and also avoid lockdep recursion:
+ */
+void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+ int trylock, int read, int check, unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(!lock_stat && !prove_locking))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+
+ current->lockdep_recursion = 1;
+ __lock_acquire(lock, subclass, trylock, read, check,
+ irqs_disabled_flags(flags), ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+
+EXPORT_SYMBOL_GPL(lock_acquire);
+
+void lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(!lock_stat && !prove_locking))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ __lock_release(lock, nested, ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+
+EXPORT_SYMBOL_GPL(lock_release);
+
+#ifdef CONFIG_LOCK_STAT
+static int
+print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
+ unsigned long ip)
+{
+ if (!debug_locks_off())
+ return 0;
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n=================================\n");
+ printk( "[ BUG: bad contention detected! ]\n");
+ printk( "---------------------------------\n");
+ printk("%s/%d is trying to contend lock (",
+ curr->comm, task_pid_nr(curr));
+ print_lockdep_cache(lock);
+ printk(") at:\n");
+ print_ip_sym(ip);
+ printk("but there are no locks held!\n");
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static void
+__lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class_stats *stats;
+ unsigned int depth;
+ int i, point;
+
+ depth = curr->lockdep_depth;
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (hlock->instance == lock)
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, ip);
+ return;
+
+found_it:
+ hlock->waittime_stamp = sched_clock();
+
+ point = lock_contention_point(hlock->class, ip);
+
+ stats = get_lock_stats(hlock->class);
+ if (point < ARRAY_SIZE(stats->contention_point))
+ stats->contention_point[i]++;
+ if (lock->cpu != smp_processor_id())
+ stats->bounces[bounce_contended + !!hlock->read]++;
+ put_lock_stats(stats);
+}
+
+static void
+__lock_acquired(struct lockdep_map *lock)
+{
+ struct task_struct *curr = current;
+ struct held_lock *hlock, *prev_hlock;
+ struct lock_class_stats *stats;
+ unsigned int depth;
+ u64 now;
+ s64 waittime = 0;
+ int i, cpu;
+
+ depth = curr->lockdep_depth;
+ if (DEBUG_LOCKS_WARN_ON(!depth))
+ return;
+
+ prev_hlock = NULL;
+ for (i = depth-1; i >= 0; i--) {
+ hlock = curr->held_locks + i;
+ /*
+ * We must not cross into another context:
+ */
+ if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+ break;
+ if (hlock->instance == lock)
+ goto found_it;
+ prev_hlock = hlock;
+ }
+ print_lock_contention_bug(curr, lock, _RET_IP_);
+ return;
+
+found_it:
+ cpu = smp_processor_id();
+ if (hlock->waittime_stamp) {
+ now = sched_clock();
+ waittime = now - hlock->waittime_stamp;
+ hlock->holdtime_stamp = now;
+ }
+
+ stats = get_lock_stats(hlock->class);
+ if (waittime) {
+ if (hlock->read)
+ lock_time_inc(&stats->read_waittime, waittime);
+ else
+ lock_time_inc(&stats->write_waittime, waittime);
+ }
+ if (lock->cpu != cpu)
+ stats->bounces[bounce_acquired + !!hlock->read]++;
+ put_lock_stats(stats);
+
+ lock->cpu = cpu;
+}
+
+void lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+ unsigned long flags;
+
+ if (unlikely(!lock_stat))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ __lock_contended(lock, ip);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_contended);
+
+void lock_acquired(struct lockdep_map *lock)
+{
+ unsigned long flags;
+
+ if (unlikely(!lock_stat))
+ return;
+
+ if (unlikely(current->lockdep_recursion))
+ return;
+
+ raw_local_irq_save(flags);
+ check_flags(flags);
+ current->lockdep_recursion = 1;
+ __lock_acquired(lock);
+ current->lockdep_recursion = 0;
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_acquired);
+#endif
+
+/*
+ * Used by the testsuite, sanitize the validator state
+ * after a simulated failure:
+ */
+
+void lockdep_reset(void)
+{
+ unsigned long flags;
+ int i;
+
+ raw_local_irq_save(flags);
+ current->curr_chain_key = 0;
+ current->lockdep_depth = 0;
+ current->lockdep_recursion = 0;
+ memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
+ nr_hardirq_chains = 0;
+ nr_softirq_chains = 0;
+ nr_process_chains = 0;
+ debug_locks = 1;
+ for (i = 0; i < CHAINHASH_SIZE; i++)
+ INIT_LIST_HEAD(chainhash_table + i);
+ raw_local_irq_restore(flags);
+}
+
+static void zap_class(struct lock_class *class)
+{
+ int i;
+
+ /*
+ * Remove all dependencies this lock is
+ * involved in:
+ */
+ for (i = 0; i < nr_list_entries; i++) {
+ if (list_entries[i].class == class)
+ list_del_rcu(&list_entries[i].entry);
+ }
+ /*
+ * Unhash the class and remove it from the all_lock_classes list:
+ */
+ list_del_rcu(&class->hash_entry);
+ list_del_rcu(&class->lock_entry);
+
+}
+
+static inline int within(void *addr, void *start, unsigned long size)
+{
+ return addr >= start && addr < start + size;
+}
+
+void lockdep_free_key_range(void *start, unsigned long size)
+{
+ struct lock_class *class, *next;
+ struct list_head *head;
+ unsigned long flags;
+ int i;
+
+ raw_local_irq_save(flags);
+ graph_lock();
+
+ /*
+ * Unhash all classes that were created by this module:
+ */
+ for (i = 0; i < CLASSHASH_SIZE; i++) {
+ head = classhash_table + i;
+ if (list_empty(head))
+ continue;
+ list_for_each_entry_safe(class, next, head, hash_entry)
+ if (within(class->key, start, size))
+ zap_class(class);
+ }
+
+ graph_unlock();
+ raw_local_irq_restore(flags);
+}
+
+void lockdep_reset_lock(struct lockdep_map *lock)
+{
+ struct lock_class *class, *next;
+ struct list_head *head;
+ unsigned long flags;
+ int i, j;
+
+ raw_local_irq_save(flags);
+
+ /*
+ * Remove all classes this lock might have:
+ */
+ for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
+ /*
+ * If the class exists we look it up and zap it:
+ */
+ class = look_up_lock_class(lock, j);
+ if (class)
+ zap_class(class);
+ }
+ /*
+ * Debug check: in the end all mapped classes should
+ * be gone.
+ */
+ graph_lock();
+ for (i = 0; i < CLASSHASH_SIZE; i++) {
+ head = classhash_table + i;
+ if (list_empty(head))
+ continue;
+ list_for_each_entry_safe(class, next, head, hash_entry) {
+ if (unlikely(class == lock->class_cache)) {
+ if (debug_locks_off_graph_unlock())
+ WARN_ON(1);
+ goto out_restore;
+ }
+ }
+ }
+ graph_unlock();
+
+out_restore:
+ raw_local_irq_restore(flags);
+}
+
+void lockdep_init(void)
+{
+ int i;
+
+ /*
+ * Some architectures have their own start_kernel()
+ * code which calls lockdep_init(), while we also
+ * call lockdep_init() from the start_kernel() itself,
+ * and we want to initialize the hashes only once:
+ */
+ if (lockdep_initialized)
+ return;
+
+ for (i = 0; i < CLASSHASH_SIZE; i++)
+ INIT_LIST_HEAD(classhash_table + i);
+
+ for (i = 0; i < CHAINHASH_SIZE; i++)
+ INIT_LIST_HEAD(chainhash_table + i);
+
+ lockdep_initialized = 1;
+}
+
+void __init lockdep_info(void)
+{
+ printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
+
+ printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
+ printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
+ printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
+ printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
+ printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
+ printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
+ printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
+
+ printk(" memory used by lock dependency info: %lu kB\n",
+ (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
+ sizeof(struct list_head) * CLASSHASH_SIZE +
+ sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
+ sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
+ sizeof(struct list_head) * CHAINHASH_SIZE) / 1024);
+
+ printk(" per task-struct memory footprint: %lu bytes\n",
+ sizeof(struct held_lock) * MAX_LOCK_DEPTH);
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+ if (lockdep_init_error) {
+ printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
+ printk("Call stack leading to lockdep invocation was:\n");
+ print_stack_trace(&lockdep_init_trace, 0);
+ }
+#endif
+}
+
+static inline int in_range(const void *start, const void *addr, const void *end)
+{
+ return addr >= start && addr <= end;
+}
+
+static void
+print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
+ const void *mem_to, struct held_lock *hlock)
+{
+ if (!debug_locks_off())
+ return;
+ if (debug_locks_silent)
+ return;
+
+ printk("\n=========================\n");
+ printk( "[ BUG: held lock freed! ]\n");
+ printk( "-------------------------\n");
+ printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
+ curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
+ print_lock(hlock);
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+}
+
+/*
+ * Called when kernel memory is freed (or unmapped), or if a lock
+ * is destroyed or reinitialized - this code checks whether there is
+ * any held lock in the memory range of <from> to <to>:
+ */
+void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
+{
+ const void *mem_to = mem_from + mem_len, *lock_from, *lock_to;
+ struct task_struct *curr = current;
+ struct held_lock *hlock;
+ unsigned long flags;
+ int i;
+
+ if (unlikely(!debug_locks))
+ return;
+
+ local_irq_save(flags);
+ for (i = 0; i < curr->lockdep_depth; i++) {
+ hlock = curr->held_locks + i;
+
+ lock_from = (void *)hlock->instance;
+ lock_to = (void *)(hlock->instance + 1);
+
+ if (!in_range(mem_from, lock_from, mem_to) &&
+ !in_range(mem_from, lock_to, mem_to))
+ continue;
+
+ print_freed_lock_bug(curr, mem_from, mem_to, hlock);
+ break;
+ }
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
+
+static void print_held_locks_bug(struct task_struct *curr)
+{
+ if (!debug_locks_off())
+ return;
+ if (debug_locks_silent)
+ return;
+
+ printk("\n=====================================\n");
+ printk( "[ BUG: lock held at task exit time! ]\n");
+ printk( "-------------------------------------\n");
+ printk("%s/%d is exiting with locks still held!\n",
+ curr->comm, task_pid_nr(curr));
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+}
+
+void debug_check_no_locks_held(struct task_struct *task)
+{
+ if (unlikely(task->lockdep_depth > 0))
+ print_held_locks_bug(task);
+}
+
+void debug_show_all_locks(void)
+{
+ struct task_struct *g, *p;
+ int count = 10;
+ int unlock = 1;
+
+ if (unlikely(!debug_locks)) {
+ printk("INFO: lockdep is turned off.\n");
+ return;
+ }
+ printk("\nShowing all locks held in the system:\n");
+
+ /*
+ * Here we try to get the tasklist_lock as hard as possible,
+ * if not successful after 2 seconds we ignore it (but keep
+ * trying). This is to enable a debug printout even if a
+ * tasklist_lock-holding task deadlocks or crashes.
+ */
+retry:
+ if (!read_trylock(&tasklist_lock)) {
+ if (count == 10)
+ printk("hm, tasklist_lock locked, retrying... ");
+ if (count) {
+ count--;
+ printk(" #%d", 10-count);
+ mdelay(200);
+ goto retry;
+ }
+ printk(" ignoring it.\n");
+ unlock = 0;
+ }
+ if (count != 10)
+ printk(" locked it.\n");
+
+ do_each_thread(g, p) {
+ if (p->lockdep_depth)
+ lockdep_print_held_locks(p);
+ if (!unlock)
+ if (read_trylock(&tasklist_lock))
+ unlock = 1;
+ } while_each_thread(g, p);
+
+ printk("\n");
+ printk("=============================================\n\n");
+
+ if (unlock)
+ read_unlock(&tasklist_lock);
+}
+
+EXPORT_SYMBOL_GPL(debug_show_all_locks);
+
+void debug_show_held_locks(struct task_struct *task)
+{
+ if (unlikely(!debug_locks)) {
+ printk("INFO: lockdep is turned off.\n");
+ return;
+ }
+ lockdep_print_held_locks(task);
+}
+
+EXPORT_SYMBOL_GPL(debug_show_held_locks);
+
+void lockdep_sys_exit(void)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(curr->lockdep_depth)) {
+ if (!debug_locks_off())
+ return;
+ printk("\n================================================\n");
+ printk( "[ BUG: lock held when returning to user space! ]\n");
+ printk( "------------------------------------------------\n");
+ printk("%s/%d is leaving the kernel with locks still held!\n",
+ curr->comm, curr->pid);
+ lockdep_print_held_locks(curr);
+ }
+}
Index: linux-2.6-lttng.stable/kernel/lockdep.c
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/lockdep.c 2007-10-29 09:51:06.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,3217 +0,0 @@
-/*
- * kernel/lockdep.c
- *
- * Runtime locking correctness validator
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <[email protected]>
- * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <[email protected]>
- *
- * this code maps all the lock dependencies as they occur in a live kernel
- * and will warn about the following classes of locking bugs:
- *
- * - lock inversion scenarios
- * - circular lock dependencies
- * - hardirq/softirq safe/unsafe locking bugs
- *
- * Bugs are reported even if the current locking scenario does not cause
- * any deadlock at this point.
- *
- * I.e. if anytime in the past two locks were taken in a different order,
- * even if it happened for another task, even if those were different
- * locks (but of the same class as this lock), this code will detect it.
- *
- * Thanks to Arjan van de Ven for coming up with the initial idea of
- * mapping lock dependencies runtime.
- */
-#include <linux/mutex.h>
-#include <linux/sched.h>
-#include <linux/delay.h>
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/interrupt.h>
-#include <linux/stacktrace.h>
-#include <linux/debug_locks.h>
-#include <linux/irqflags.h>
-#include <linux/utsname.h>
-#include <linux/hash.h>
-
-#include <asm/sections.h>
-
-#include "lockdep_internals.h"
-
-#ifdef CONFIG_PROVE_LOCKING
-int prove_locking = 1;
-module_param(prove_locking, int, 0644);
-#else
-#define prove_locking 0
-#endif
-
-#ifdef CONFIG_LOCK_STAT
-int lock_stat = 1;
-module_param(lock_stat, int, 0644);
-#else
-#define lock_stat 0
-#endif
-
-/*
- * lockdep_lock: protects the lockdep graph, the hashes and the
- * class/list/hash allocators.
- *
- * This is one of the rare exceptions where it's justified
- * to use a raw spinlock - we really dont want the spinlock
- * code to recurse back into the lockdep code...
- */
-static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
-
-static int graph_lock(void)
-{
- __raw_spin_lock(&lockdep_lock);
- /*
- * Make sure that if another CPU detected a bug while
- * walking the graph we dont change it (while the other
- * CPU is busy printing out stuff with the graph lock
- * dropped already)
- */
- if (!debug_locks) {
- __raw_spin_unlock(&lockdep_lock);
- return 0;
- }
- return 1;
-}
-
-static inline int graph_unlock(void)
-{
- if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
- return DEBUG_LOCKS_WARN_ON(1);
-
- __raw_spin_unlock(&lockdep_lock);
- return 0;
-}
-
-/*
- * Turn lock debugging off and return with 0 if it was off already,
- * and also release the graph lock:
- */
-static inline int debug_locks_off_graph_unlock(void)
-{
- int ret = debug_locks_off();
-
- __raw_spin_unlock(&lockdep_lock);
-
- return ret;
-}
-
-static int lockdep_initialized;
-
-unsigned long nr_list_entries;
-static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
-
-/*
- * All data structures here are protected by the global debug_lock.
- *
- * Mutex key structs only get allocated, once during bootup, and never
- * get freed - this significantly simplifies the debugging code.
- */
-unsigned long nr_lock_classes;
-static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
-
-#ifdef CONFIG_LOCK_STAT
-static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
-
-static int lock_contention_point(struct lock_class *class, unsigned long ip)
-{
- int i;
-
- for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
- if (class->contention_point[i] == 0) {
- class->contention_point[i] = ip;
- break;
- }
- if (class->contention_point[i] == ip)
- break;
- }
-
- return i;
-}
-
-static void lock_time_inc(struct lock_time *lt, s64 time)
-{
- if (time > lt->max)
- lt->max = time;
-
- if (time < lt->min || !lt->min)
- lt->min = time;
-
- lt->total += time;
- lt->nr++;
-}
-
-static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
-{
- dst->min += src->min;
- dst->max += src->max;
- dst->total += src->total;
- dst->nr += src->nr;
-}
-
-struct lock_class_stats lock_stats(struct lock_class *class)
-{
- struct lock_class_stats stats;
- int cpu, i;
-
- memset(&stats, 0, sizeof(struct lock_class_stats));
- for_each_possible_cpu(cpu) {
- struct lock_class_stats *pcs =
- &per_cpu(lock_stats, cpu)[class - lock_classes];
-
- for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
- stats.contention_point[i] += pcs->contention_point[i];
-
- lock_time_add(&pcs->read_waittime, &stats.read_waittime);
- lock_time_add(&pcs->write_waittime, &stats.write_waittime);
-
- lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
- lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
-
- for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
- stats.bounces[i] += pcs->bounces[i];
- }
-
- return stats;
-}
-
-void clear_lock_stats(struct lock_class *class)
-{
- int cpu;
-
- for_each_possible_cpu(cpu) {
- struct lock_class_stats *cpu_stats =
- &per_cpu(lock_stats, cpu)[class - lock_classes];
-
- memset(cpu_stats, 0, sizeof(struct lock_class_stats));
- }
- memset(class->contention_point, 0, sizeof(class->contention_point));
-}
-
-static struct lock_class_stats *get_lock_stats(struct lock_class *class)
-{
- return &get_cpu_var(lock_stats)[class - lock_classes];
-}
-
-static void put_lock_stats(struct lock_class_stats *stats)
-{
- put_cpu_var(lock_stats);
-}
-
-static void lock_release_holdtime(struct held_lock *hlock)
-{
- struct lock_class_stats *stats;
- s64 holdtime;
-
- if (!lock_stat)
- return;
-
- holdtime = sched_clock() - hlock->holdtime_stamp;
-
- stats = get_lock_stats(hlock->class);
- if (hlock->read)
- lock_time_inc(&stats->read_holdtime, holdtime);
- else
- lock_time_inc(&stats->write_holdtime, holdtime);
- put_lock_stats(stats);
-}
-#else
-static inline void lock_release_holdtime(struct held_lock *hlock)
-{
-}
-#endif
-
-/*
- * We keep a global list of all lock classes. The list only grows,
- * never shrinks. The list is only accessed with the lockdep
- * spinlock lock held.
- */
-LIST_HEAD(all_lock_classes);
-
-/*
- * The lockdep classes are in a hash-table as well, for fast lookup:
- */
-#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
-#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
-#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
-#define classhashentry(key) (classhash_table + __classhashfn((key)))
-
-static struct list_head classhash_table[CLASSHASH_SIZE];
-
-/*
- * We put the lock dependency chains into a hash-table as well, to cache
- * their existence:
- */
-#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
-#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
-#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
-#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
-
-static struct list_head chainhash_table[CHAINHASH_SIZE];
-
-/*
- * The hash key of the lock dependency chains is a hash itself too:
- * it's a hash of all locks taken up to that lock, including that lock.
- * It's a 64-bit hash, because it's important for the keys to be
- * unique.
- */
-#define iterate_chain_key(key1, key2) \
- (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
- ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
- (key2))
-
-void lockdep_off(void)
-{
- current->lockdep_recursion++;
-}
-
-EXPORT_SYMBOL(lockdep_off);
-
-void lockdep_on(void)
-{
- current->lockdep_recursion--;
-}
-
-EXPORT_SYMBOL(lockdep_on);
-
-/*
- * Debugging switches:
- */
-
-#define VERBOSE 0
-#define VERY_VERBOSE 0
-
-#if VERBOSE
-# define HARDIRQ_VERBOSE 1
-# define SOFTIRQ_VERBOSE 1
-#else
-# define HARDIRQ_VERBOSE 0
-# define SOFTIRQ_VERBOSE 0
-#endif
-
-#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
-/*
- * Quick filtering for interesting events:
- */
-static int class_filter(struct lock_class *class)
-{
-#if 0
- /* Example */
- if (class->name_version == 1 &&
- !strcmp(class->name, "lockname"))
- return 1;
- if (class->name_version == 1 &&
- !strcmp(class->name, "&struct->lockfield"))
- return 1;
-#endif
- /* Filter everything else. 1 would be to allow everything else */
- return 0;
-}
-#endif
-
-static int verbose(struct lock_class *class)
-{
-#if VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the graph_lock.
- */
-unsigned long nr_stack_trace_entries;
-static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
-
-static int save_trace(struct stack_trace *trace)
-{
- trace->nr_entries = 0;
- trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
- trace->entries = stack_trace + nr_stack_trace_entries;
-
- trace->skip = 3;
-
- save_stack_trace(trace);
-
- trace->max_entries = trace->nr_entries;
-
- nr_stack_trace_entries += trace->nr_entries;
-
- if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
- printk("turning off the locking correctness validator.\n");
- dump_stack();
-
- return 0;
- }
-
- return 1;
-}
-
-unsigned int nr_hardirq_chains;
-unsigned int nr_softirq_chains;
-unsigned int nr_process_chains;
-unsigned int max_lockdep_depth;
-unsigned int max_recursion_depth;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-/*
- * We cannot printk in early bootup code. Not even early_printk()
- * might work. So we mark any initialization errors and printk
- * about it later on, in lockdep_info().
- */
-static int lockdep_init_error;
-static unsigned long lockdep_init_trace_data[20];
-static struct stack_trace lockdep_init_trace = {
- .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
- .entries = lockdep_init_trace_data,
-};
-
-/*
- * Various lockdep statistics:
- */
-atomic_t chain_lookup_hits;
-atomic_t chain_lookup_misses;
-atomic_t hardirqs_on_events;
-atomic_t hardirqs_off_events;
-atomic_t redundant_hardirqs_on;
-atomic_t redundant_hardirqs_off;
-atomic_t softirqs_on_events;
-atomic_t softirqs_off_events;
-atomic_t redundant_softirqs_on;
-atomic_t redundant_softirqs_off;
-atomic_t nr_unused_locks;
-atomic_t nr_cyclic_checks;
-atomic_t nr_cyclic_check_recursions;
-atomic_t nr_find_usage_forwards_checks;
-atomic_t nr_find_usage_forwards_recursions;
-atomic_t nr_find_usage_backwards_checks;
-atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr) atomic_inc(ptr)
-# define debug_atomic_dec(ptr) atomic_dec(ptr)
-# define debug_atomic_read(ptr) atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr) do { } while (0)
-# define debug_atomic_dec(ptr) do { } while (0)
-# define debug_atomic_read(ptr) 0
-#endif
-
-/*
- * Locking printouts:
- */
-
-static const char *usage_str[] =
-{
- [LOCK_USED] = "initial-use ",
- [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W",
- [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W",
- [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W",
- [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W",
- [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R",
- [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R",
- [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R",
- [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R",
-};
-
-const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
-{
- return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
-}
-
-void
-get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4)
-{
- *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.';
-
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
- *c1 = '+';
- else
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
- *c1 = '-';
-
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
- *c2 = '+';
- else
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
- *c2 = '-';
-
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
- *c3 = '-';
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) {
- *c3 = '+';
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
- *c3 = '?';
- }
-
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
- *c4 = '-';
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) {
- *c4 = '+';
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
- *c4 = '?';
- }
-}
-
-static void print_lock_name(struct lock_class *class)
-{
- char str[KSYM_NAME_LEN], c1, c2, c3, c4;
- const char *name;
-
- get_usage_chars(class, &c1, &c2, &c3, &c4);
-
- name = class->name;
- if (!name) {
- name = __get_key_name(class->key, str);
- printk(" (%s", name);
- } else {
- printk(" (%s", name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- if (class->subclass)
- printk("/%d", class->subclass);
- }
- printk("){%c%c%c%c}", c1, c2, c3, c4);
-}
-
-static void print_lockdep_cache(struct lockdep_map *lock)
-{
- const char *name;
- char str[KSYM_NAME_LEN];
-
- name = lock->name;
- if (!name)
- name = __get_key_name(lock->key->subkeys, str);
-
- printk("%s", name);
-}
-
-static void print_lock(struct held_lock *hlock)
-{
- print_lock_name(hlock->class);
- printk(", at: ");
- print_ip_sym(hlock->acquire_ip);
-}
-
-static void lockdep_print_held_locks(struct task_struct *curr)
-{
- int i, depth = curr->lockdep_depth;
-
- if (!depth) {
- printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
- return;
- }
- printk("%d lock%s held by %s/%d:\n",
- depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
-
- for (i = 0; i < depth; i++) {
- printk(" #%d: ", i);
- print_lock(curr->held_locks + i);
- }
-}
-
-static void print_lock_class_header(struct lock_class *class, int depth)
-{
- int bit;
-
- printk("%*s->", depth, "");
- print_lock_name(class);
- printk(" ops: %lu", class->ops);
- printk(" {\n");
-
- for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
- if (class->usage_mask & (1 << bit)) {
- int len = depth;
-
- len += printk("%*s %s", depth, "", usage_str[bit]);
- len += printk(" at:\n");
- print_stack_trace(class->usage_traces + bit, len);
- }
- }
- printk("%*s }\n", depth, "");
-
- printk("%*s ... key at: ",depth,"");
- print_ip_sym((unsigned long)class->key);
-}
-
-/*
- * printk all lock dependencies starting at <entry>:
- */
-static void print_lock_dependencies(struct lock_class *class, int depth)
-{
- struct lock_list *entry;
-
- if (DEBUG_LOCKS_WARN_ON(depth >= 20))
- return;
-
- print_lock_class_header(class, depth);
-
- list_for_each_entry(entry, &class->locks_after, entry) {
- if (DEBUG_LOCKS_WARN_ON(!entry->class))
- return;
-
- print_lock_dependencies(entry->class, depth + 1);
-
- printk("%*s ... acquired at:\n",depth,"");
- print_stack_trace(&entry->trace, 2);
- printk("\n");
- }
-}
-
-static void print_kernel_version(void)
-{
- printk("%s %.*s\n", init_utsname()->release,
- (int)strcspn(init_utsname()->version, " "),
- init_utsname()->version);
-}
-
-static int very_verbose(struct lock_class *class)
-{
-#if VERY_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-/*
- * Is this the address of a static object:
- */
-static int static_obj(void *obj)
-{
- unsigned long start = (unsigned long) &_stext,
- end = (unsigned long) &_end,
- addr = (unsigned long) obj;
-#ifdef CONFIG_SMP
- int i;
-#endif
-
- /*
- * static variable?
- */
- if ((addr >= start) && (addr < end))
- return 1;
-
-#ifdef CONFIG_SMP
- /*
- * percpu var?
- */
- for_each_possible_cpu(i) {
- start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
- end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
- + per_cpu_offset(i);
-
- if ((addr >= start) && (addr < end))
- return 1;
- }
-#endif
-
- /*
- * module var?
- */
- return is_module_address(addr);
-}
-
-/*
- * To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
- */
-static int count_matching_names(struct lock_class *new_class)
-{
- struct lock_class *class;
- int count = 0;
-
- if (!new_class->name)
- return 0;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
- if (new_class->key - new_class->subclass == class->key)
- return class->name_version;
- if (class->name && !strcmp(class->name, new_class->name))
- count = max(count, class->name_version);
- }
-
- return count + 1;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- /*
- * If the architecture calls into lockdep before initializing
- * the hashes then we'll warn about it later. (we cannot printk
- * right now)
- */
- if (unlikely(!lockdep_initialized)) {
- lockdep_init();
- lockdep_init_error = 1;
- save_stack_trace(&lockdep_init_trace);
- }
-#endif
-
- /*
- * Static locks do not have their class-keys yet - for them the key
- * is the lock object itself:
- */
- if (unlikely(!lock->key))
- lock->key = (void *)lock;
-
- /*
- * NOTE: the class-key must be unique. For dynamic locks, a static
- * lock_class_key variable is passed in through the mutex_init()
- * (or spin_lock_init()) call - which acts as the key. For static
- * locks we use the lock object itself as the key.
- */
- BUILD_BUG_ON(sizeof(struct lock_class_key) >
- sizeof(struct lockdep_map));
-
- key = lock->key->subkeys + subclass;
-
- hash_head = classhashentry(key);
-
- /*
- * We can walk the hash lockfree, because the hash only
- * grows, and we are careful when adding entries to the end:
- */
- list_for_each_entry(class, hash_head, hash_entry) {
- if (class->key == key) {
- WARN_ON_ONCE(class->name != lock->name);
- return class;
- }
- }
-
- return NULL;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
-{
- struct lockdep_subclass_key *key;
- struct list_head *hash_head;
- struct lock_class *class;
- unsigned long flags;
-
- class = look_up_lock_class(lock, subclass);
- if (likely(class))
- return class;
-
- /*
- * Debug-check: all keys must be persistent!
- */
- if (!static_obj(lock->key)) {
- debug_locks_off();
- printk("INFO: trying to register non-static key.\n");
- printk("the code is fine but needs lockdep annotation.\n");
- printk("turning off the locking correctness validator.\n");
- dump_stack();
-
- return NULL;
- }
-
- key = lock->key->subkeys + subclass;
- hash_head = classhashentry(key);
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- /*
- * We have to do the hash-walk again, to avoid races
- * with another CPU:
- */
- list_for_each_entry(class, hash_head, hash_entry)
- if (class->key == key)
- goto out_unlock_set;
- /*
- * Allocate a new key from the static array, and add it to
- * the hash:
- */
- if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
- if (!debug_locks_off_graph_unlock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- raw_local_irq_restore(flags);
-
- printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
- printk("turning off the locking correctness validator.\n");
- return NULL;
- }
- class = lock_classes + nr_lock_classes++;
- debug_atomic_inc(&nr_unused_locks);
- class->key = key;
- class->name = lock->name;
- class->subclass = subclass;
- INIT_LIST_HEAD(&class->lock_entry);
- INIT_LIST_HEAD(&class->locks_before);
- INIT_LIST_HEAD(&class->locks_after);
- class->name_version = count_matching_names(class);
- /*
- * We use RCU's safe list-add method to make
- * parallel walking of the hash-list safe:
- */
- list_add_tail_rcu(&class->hash_entry, hash_head);
-
- if (verbose(class)) {
- graph_unlock();
- raw_local_irq_restore(flags);
-
- printk("\nnew class %p: %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
-
- raw_local_irq_save(flags);
- if (!graph_lock()) {
- raw_local_irq_restore(flags);
- return NULL;
- }
- }
-out_unlock_set:
- graph_unlock();
- raw_local_irq_restore(flags);
-
- if (!subclass || force)
- lock->class_cache = class;
-
- if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
- return NULL;
-
- return class;
-}
-
-#ifdef CONFIG_PROVE_LOCKING
-/*
- * Allocate a lockdep entry. (assumes the graph_lock held, returns
- * with NULL on failure)
- */
-static struct lock_list *alloc_list_entry(void)
-{
- if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
- if (!debug_locks_off_graph_unlock())
- return NULL;
-
- printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
- printk("turning off the locking correctness validator.\n");
- return NULL;
- }
- return list_entries + nr_list_entries++;
-}
-
-/*
- * Add a new dependency to the head of the list:
- */
-static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
- struct list_head *head, unsigned long ip, int distance)
-{
- struct lock_list *entry;
- /*
- * Lock not present yet - get a new dependency struct and
- * add it to the list:
- */
- entry = alloc_list_entry();
- if (!entry)
- return 0;
-
- entry->class = this;
- entry->distance = distance;
- if (!save_trace(&entry->trace))
- return 0;
-
- /*
- * Since we never remove from the dependency list, the list can
- * be walked lockless by other CPUs, it's only allocation
- * that must be protected by the spinlock. But this also means
- * we must make new entries visible only once writes to the
- * entry become visible - hence the RCU op:
- */
- list_add_tail_rcu(&entry->entry, head);
-
- return 1;
-}
-
-/*
- * Recursive, forwards-direction lock-dependency checking, used for
- * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
- * checking.
- *
- * (to keep the stackframe of the recursive functions small we
- * use these global variables, and we also mark various helper
- * functions as noinline.)
- */
-static struct held_lock *check_source, *check_target;
-
-/*
- * Print a dependency chain entry (this is only done when a deadlock
- * has been detected):
- */
-static noinline int
-print_circular_bug_entry(struct lock_list *target, unsigned int depth)
-{
- if (debug_locks_silent)
- return 0;
- printk("\n-> #%u", depth);
- print_lock_name(target->class);
- printk(":\n");
- print_stack_trace(&target->trace, 6);
-
- return 0;
-}
-
-/*
- * When a circular dependency is detected, print the
- * header first:
- */
-static noinline int
-print_circular_bug_header(struct lock_list *entry, unsigned int depth)
-{
- struct task_struct *curr = current;
-
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n=======================================================\n");
- printk( "[ INFO: possible circular locking dependency detected ]\n");
- print_kernel_version();
- printk( "-------------------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(check_source);
- printk("\nbut task is already holding lock:\n");
- print_lock(check_target);
- printk("\nwhich lock already depends on the new lock.\n\n");
- printk("\nthe existing dependency chain (in reverse order) is:\n");
-
- print_circular_bug_entry(entry, depth);
-
- return 0;
-}
-
-static noinline int print_circular_bug_tail(void)
-{
- struct task_struct *curr = current;
- struct lock_list this;
-
- if (debug_locks_silent)
- return 0;
-
- this.class = check_source->class;
- if (!save_trace(&this.trace))
- return 0;
-
- print_circular_bug_entry(&this, 0);
-
- printk("\nother info that might help us debug this:\n\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-#define RECURSION_LIMIT 40
-
-static int noinline print_infinite_recursion_bug(void)
-{
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- WARN_ON(1);
-
- return 0;
-}
-
-/*
- * Prove that the dependency graph starting at <entry> can not
- * lead to <target>. Print an error and return 0 if it does.
- */
-static noinline int
-check_noncircular(struct lock_class *source, unsigned int depth)
-{
- struct lock_list *entry;
-
- debug_atomic_inc(&nr_cyclic_check_recursions);
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_after, entry) {
- if (entry->class == check_target->class)
- return print_circular_bug_header(entry, depth+1);
- debug_atomic_inc(&nr_cyclic_checks);
- if (!check_noncircular(entry->class, depth+1))
- return print_circular_bug_entry(entry, depth+1);
- }
- return 1;
-}
-
-#ifdef CONFIG_TRACE_IRQFLAGS
-/*
- * Forwards and backwards subgraph searching, for the purposes of
- * proving that two subgraphs can be connected by a new dependency
- * without creating any illegal irq-safe -> irq-unsafe lock dependency.
- */
-static enum lock_usage_bit find_usage_bit;
-static struct lock_class *forwards_match, *backwards_match;
-
-/*
- * Find a node in the forwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
- *
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <forwards_match>.
- *
- * Return 1 otherwise and keep <forwards_match> unchanged.
- * Return 0 on error.
- */
-static noinline int
-find_usage_forwards(struct lock_class *source, unsigned int depth)
-{
- struct lock_list *entry;
- int ret;
-
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
-
- debug_atomic_inc(&nr_find_usage_forwards_checks);
- if (source->usage_mask & (1 << find_usage_bit)) {
- forwards_match = source;
- return 2;
- }
-
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_after, entry) {
- debug_atomic_inc(&nr_find_usage_forwards_recursions);
- ret = find_usage_forwards(entry->class, depth+1);
- if (ret == 2 || ret == 0)
- return ret;
- }
- return 1;
-}
-
-/*
- * Find a node in the backwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
- *
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <backwards_match>.
- *
- * Return 1 otherwise and keep <backwards_match> unchanged.
- * Return 0 on error.
- */
-static noinline int
-find_usage_backwards(struct lock_class *source, unsigned int depth)
-{
- struct lock_list *entry;
- int ret;
-
- if (!__raw_spin_is_locked(&lockdep_lock))
- return DEBUG_LOCKS_WARN_ON(1);
-
- if (depth > max_recursion_depth)
- max_recursion_depth = depth;
- if (depth >= RECURSION_LIMIT)
- return print_infinite_recursion_bug();
-
- debug_atomic_inc(&nr_find_usage_backwards_checks);
- if (source->usage_mask & (1 << find_usage_bit)) {
- backwards_match = source;
- return 2;
- }
-
- /*
- * Check this lock's dependency list:
- */
- list_for_each_entry(entry, &source->locks_before, entry) {
- debug_atomic_inc(&nr_find_usage_backwards_recursions);
- ret = find_usage_backwards(entry->class, depth+1);
- if (ret == 2 || ret == 0)
- return ret;
- }
- return 1;
-}
-
-static int
-print_bad_irq_dependency(struct task_struct *curr,
- struct held_lock *prev,
- struct held_lock *next,
- enum lock_usage_bit bit1,
- enum lock_usage_bit bit2,
- const char *irqclass)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n======================================================\n");
- printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
- irqclass, irqclass);
- print_kernel_version();
- printk( "------------------------------------------------------\n");
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
- curr->comm, task_pid_nr(curr),
- curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
- curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
- curr->hardirqs_enabled,
- curr->softirqs_enabled);
- print_lock(next);
-
- printk("\nand this task is already holding:\n");
- print_lock(prev);
- printk("which would create a new lock dependency:\n");
- print_lock_name(prev->class);
- printk(" ->");
- print_lock_name(next->class);
- printk("\n");
-
- printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
- irqclass);
- print_lock_name(backwards_match);
- printk("\n... which became %s-irq-safe at:\n", irqclass);
-
- print_stack_trace(backwards_match->usage_traces + bit1, 1);
-
- printk("\nto a %s-irq-unsafe lock:\n", irqclass);
- print_lock_name(forwards_match);
- printk("\n... which became %s-irq-unsafe at:\n", irqclass);
- printk("...");
-
- print_stack_trace(forwards_match->usage_traces + bit2, 1);
-
- printk("\nother info that might help us debug this:\n\n");
- lockdep_print_held_locks(curr);
-
- printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass);
- print_lock_dependencies(backwards_match, 0);
-
- printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass);
- print_lock_dependencies(forwards_match, 0);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static int
-check_usage(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, enum lock_usage_bit bit_backwards,
- enum lock_usage_bit bit_forwards, const char *irqclass)
-{
- int ret;
-
- find_usage_bit = bit_backwards;
- /* fills in <backwards_match> */
- ret = find_usage_backwards(prev->class, 0);
- if (!ret || ret == 1)
- return ret;
-
- find_usage_bit = bit_forwards;
- ret = find_usage_forwards(next->class, 0);
- if (!ret || ret == 1)
- return ret;
- /* ret == 2 */
- return print_bad_irq_dependency(curr, prev, next,
- bit_backwards, bit_forwards, irqclass);
-}
-
-static int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
- /*
- * Prove that the new dependency does not connect a hardirq-safe
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
- LOCK_ENABLED_HARDIRQS, "hard"))
- return 0;
-
- /*
- * Prove that the new dependency does not connect a hardirq-safe-read
- * lock with a hardirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
- LOCK_ENABLED_HARDIRQS, "hard-read"))
- return 0;
-
- /*
- * Prove that the new dependency does not connect a softirq-safe
- * lock with a softirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
- LOCK_ENABLED_SOFTIRQS, "soft"))
- return 0;
- /*
- * Prove that the new dependency does not connect a softirq-safe-read
- * lock with a softirq-unsafe lock - to achieve this we search
- * the backwards-subgraph starting at <prev>, and the
- * forwards-subgraph starting at <next>:
- */
- if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
- LOCK_ENABLED_SOFTIRQS, "soft"))
- return 0;
-
- return 1;
-}
-
-static void inc_chains(void)
-{
- if (current->hardirq_context)
- nr_hardirq_chains++;
- else {
- if (current->softirq_context)
- nr_softirq_chains++;
- else
- nr_process_chains++;
- }
-}
-
-#else
-
-static inline int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
- return 1;
-}
-
-static inline void inc_chains(void)
-{
- nr_process_chains++;
-}
-
-#endif
-
-static int
-print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n=============================================\n");
- printk( "[ INFO: possible recursive locking detected ]\n");
- print_kernel_version();
- printk( "---------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(next);
- printk("\nbut task is already holding lock:\n");
- print_lock(prev);
-
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Check whether we are holding such a class already.
- *
- * (Note that this has to be done separately, because the graph cannot
- * detect such classes of deadlocks.)
- *
- * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
- */
-static int
-check_deadlock(struct task_struct *curr, struct held_lock *next,
- struct lockdep_map *next_instance, int read)
-{
- struct held_lock *prev;
- int i;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- prev = curr->held_locks + i;
- if (prev->class != next->class)
- continue;
- /*
- * Allow read-after-read recursion of the same
- * lock class (i.e. read_lock(lock)+read_lock(lock)):
- */
- if ((read == 2) && prev->read)
- return 2;
- return print_deadlock_bug(curr, prev, next);
- }
- return 1;
-}
-
-/*
- * There was a chain-cache miss, and we are about to add a new dependency
- * to a previous lock. We recursively validate the following rules:
- *
- * - would the adding of the <prev> -> <next> dependency create a
- * circular dependency in the graph? [== circular deadlock]
- *
- * - does the new prev->next dependency connect any hardirq-safe lock
- * (in the full backwards-subgraph starting at <prev>) with any
- * hardirq-unsafe lock (in the full forwards-subgraph starting at
- * <next>)? [== illegal lock inversion with hardirq contexts]
- *
- * - does the new prev->next dependency connect any softirq-safe lock
- * (in the full backwards-subgraph starting at <prev>) with any
- * softirq-unsafe lock (in the full forwards-subgraph starting at
- * <next>)? [== illegal lock inversion with softirq contexts]
- *
- * any of these scenarios could lead to a deadlock.
- *
- * Then if all the validations pass, we add the forwards and backwards
- * dependency.
- */
-static int
-check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance)
-{
- struct lock_list *entry;
- int ret;
-
- /*
- * Prove that the new <prev> -> <next> dependency would not
- * create a circular dependency in the graph. (We do this by
- * forward-recursing into the graph starting at <next>, and
- * checking whether we can reach <prev>.)
- *
- * We are using global variables to control the recursion, to
- * keep the stackframe size of the recursive functions low:
- */
- check_source = next;
- check_target = prev;
- if (!(check_noncircular(next->class, 0)))
- return print_circular_bug_tail();
-
- if (!check_prev_add_irq(curr, prev, next))
- return 0;
-
- /*
- * For recursive read-locks we do all the dependency checks,
- * but we dont store read-triggered dependencies (only
- * write-triggered dependencies). This ensures that only the
- * write-side dependencies matter, and that if for example a
- * write-lock never takes any other locks, then the reads are
- * equivalent to a NOP.
- */
- if (next->read == 2 || prev->read == 2)
- return 1;
- /*
- * Is the <prev> -> <next> dependency already present?
- *
- * (this may occur even though this is a new chain: consider
- * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
- * chains - the second one will be new, but L1 already has
- * L2 added to its dependency list, due to the first chain.)
- */
- list_for_each_entry(entry, &prev->class->locks_after, entry) {
- if (entry->class == next->class) {
- if (distance == 1)
- entry->distance = 1;
- return 2;
- }
- }
-
- /*
- * Ok, all validations passed, add the new lock
- * to the previous lock's dependency list:
- */
- ret = add_lock_to_list(prev->class, next->class,
- &prev->class->locks_after, next->acquire_ip, distance);
-
- if (!ret)
- return 0;
-
- ret = add_lock_to_list(next->class, prev->class,
- &next->class->locks_before, next->acquire_ip, distance);
- if (!ret)
- return 0;
-
- /*
- * Debugging printouts:
- */
- if (verbose(prev->class) || verbose(next->class)) {
- graph_unlock();
- printk("\n new dependency: ");
- print_lock_name(prev->class);
- printk(" => ");
- print_lock_name(next->class);
- printk("\n");
- dump_stack();
- return graph_lock();
- }
- return 1;
-}
-
-/*
- * Add the dependency to all directly-previous locks that are 'relevant'.
- * The ones that are relevant are (in increasing distance from curr):
- * all consecutive trylock entries and the final non-trylock entry - or
- * the end of this context's lock-chain - whichever comes first.
- */
-static int
-check_prevs_add(struct task_struct *curr, struct held_lock *next)
-{
- int depth = curr->lockdep_depth;
- struct held_lock *hlock;
-
- /*
- * Debugging checks.
- *
- * Depth must not be zero for a non-head lock:
- */
- if (!depth)
- goto out_bug;
- /*
- * At least two relevant locks must exist for this
- * to be a head:
- */
- if (curr->held_locks[depth].irq_context !=
- curr->held_locks[depth-1].irq_context)
- goto out_bug;
-
- for (;;) {
- int distance = curr->lockdep_depth - depth + 1;
- hlock = curr->held_locks + depth-1;
- /*
- * Only non-recursive-read entries get new dependencies
- * added:
- */
- if (hlock->read != 2) {
- if (!check_prev_add(curr, hlock, next, distance))
- return 0;
- /*
- * Stop after the first non-trylock entry,
- * as non-trylock entries have added their
- * own direct dependencies already, so this
- * lock is connected to them indirectly:
- */
- if (!hlock->trylock)
- break;
- }
- depth--;
- /*
- * End of lock-stack?
- */
- if (!depth)
- break;
- /*
- * Stop the search if we cross into another context:
- */
- if (curr->held_locks[depth].irq_context !=
- curr->held_locks[depth-1].irq_context)
- break;
- }
- return 1;
-out_bug:
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- WARN_ON(1);
-
- return 0;
-}
-
-unsigned long nr_lock_chains;
-static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-
-/*
- * Look up a dependency chain. If the key is not present yet then
- * add it and return 1 - in this case the new dependency chain is
- * validated. If the key is already hashed, return 0.
- * (On return with 1 graph_lock is held.)
- */
-static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
-{
- struct list_head *hash_head = chainhashentry(chain_key);
- struct lock_chain *chain;
-
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
- /*
- * We can walk it lock-free, because entries only get added
- * to the hash:
- */
- list_for_each_entry(chain, hash_head, entry) {
- if (chain->chain_key == chain_key) {
-cache_hit:
- debug_atomic_inc(&chain_lookup_hits);
- if (very_verbose(class))
- printk("\nhash chain already cached, key: "
- "%016Lx tail class: [%p] %s\n",
- (unsigned long long)chain_key,
- class->key, class->name);
- return 0;
- }
- }
- if (very_verbose(class))
- printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
- (unsigned long long)chain_key, class->key, class->name);
- /*
- * Allocate a new chain entry from the static array, and add
- * it to the hash:
- */
- if (!graph_lock())
- return 0;
- /*
- * We have to walk the chain again locked - to avoid duplicates:
- */
- list_for_each_entry(chain, hash_head, entry) {
- if (chain->chain_key == chain_key) {
- graph_unlock();
- goto cache_hit;
- }
- }
- if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
- if (!debug_locks_off_graph_unlock())
- return 0;
-
- printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
- printk("turning off the locking correctness validator.\n");
- return 0;
- }
- chain = lock_chains + nr_lock_chains++;
- chain->chain_key = chain_key;
- list_add_tail_rcu(&chain->entry, hash_head);
- debug_atomic_inc(&chain_lookup_misses);
- inc_chains();
-
- return 1;
-}
-
-static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
- struct held_lock *hlock, int chain_head, u64 chain_key)
-{
- /*
- * Trylock needs to maintain the stack of held locks, but it
- * does not add new dependencies, because trylock can be done
- * in any order.
- *
- * We look up the chain_key and do the O(N^2) check and update of
- * the dependencies only if this is a new dependency chain.
- * (If lookup_chain_cache() returns with 1 it acquires
- * graph_lock for us)
- */
- if (!hlock->trylock && (hlock->check == 2) &&
- lookup_chain_cache(chain_key, hlock->class)) {
- /*
- * Check whether last held lock:
- *
- * - is irq-safe, if this lock is irq-unsafe
- * - is softirq-safe, if this lock is hardirq-unsafe
- *
- * And check whether the new lock's dependency graph
- * could lead back to the previous lock.
- *
- * any of these scenarios could lead to a deadlock. If
- * All validations
- */
- int ret = check_deadlock(curr, hlock, lock, hlock->read);
-
- if (!ret)
- return 0;
- /*
- * Mark recursive read, as we jump over it when
- * building dependencies (just like we jump over
- * trylock entries):
- */
- if (ret == 2)
- hlock->read = 2;
- /*
- * Add dependency only if this lock is not the head
- * of the chain, and if it's not a secondary read-lock:
- */
- if (!chain_head && ret != 2)
- if (!check_prevs_add(curr, hlock))
- return 0;
- graph_unlock();
- } else
- /* after lookup_chain_cache(): */
- if (unlikely(!debug_locks))
- return 0;
-
- return 1;
-}
-#else
-static inline int validate_chain(struct task_struct *curr,
- struct lockdep_map *lock, struct held_lock *hlock,
- int chain_head, u64 chain_key)
-{
- return 1;
-}
-#endif
-
-/*
- * We are building curr_chain_key incrementally, so double-check
- * it from scratch, to make sure that it's done correctly:
- */
-static void check_chain_key(struct task_struct *curr)
-{
-#ifdef CONFIG_DEBUG_LOCKDEP
- struct held_lock *hlock, *prev_hlock = NULL;
- unsigned int i, id;
- u64 chain_key = 0;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
- if (chain_key != hlock->prev_chain_key) {
- debug_locks_off();
- printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n",
- curr->lockdep_depth, i,
- (unsigned long long)chain_key,
- (unsigned long long)hlock->prev_chain_key);
- WARN_ON(1);
- return;
- }
- id = hlock->class - lock_classes;
- if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
- return;
-
- if (prev_hlock && (prev_hlock->irq_context !=
- hlock->irq_context))
- chain_key = 0;
- chain_key = iterate_chain_key(chain_key, id);
- prev_hlock = hlock;
- }
- if (chain_key != curr->curr_chain_key) {
- debug_locks_off();
- printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n",
- curr->lockdep_depth, i,
- (unsigned long long)chain_key,
- (unsigned long long)curr->curr_chain_key);
- WARN_ON(1);
- }
-#endif
-}
-
-static int
-print_usage_bug(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n=================================\n");
- printk( "[ INFO: inconsistent lock state ]\n");
- print_kernel_version();
- printk( "---------------------------------\n");
-
- printk("inconsistent {%s} -> {%s} usage.\n",
- usage_str[prev_bit], usage_str[new_bit]);
-
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
- curr->comm, task_pid_nr(curr),
- trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
- trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
- trace_hardirqs_enabled(curr),
- trace_softirqs_enabled(curr));
- print_lock(this);
-
- printk("{%s} state was registered at:\n", usage_str[prev_bit]);
- print_stack_trace(this->class->usage_traces + prev_bit, 1);
-
- print_irqtrace_events(curr);
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Print out an error if an invalid bit is set:
- */
-static inline int
-valid_state(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
-{
- if (unlikely(this->class->usage_mask & (1 << bad_bit)))
- return print_usage_bug(curr, this, bad_bit, new_bit);
- return 1;
-}
-
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit);
-
-#ifdef CONFIG_TRACE_IRQFLAGS
-
-/*
- * print irq inversion bug:
- */
-static int
-print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
- struct held_lock *this, int forwards,
- const char *irqclass)
-{
- if (!debug_locks_off_graph_unlock() || debug_locks_silent)
- return 0;
-
- printk("\n=========================================================\n");
- printk( "[ INFO: possible irq lock inversion dependency detected ]\n");
- print_kernel_version();
- printk( "---------------------------------------------------------\n");
- printk("%s/%d just changed the state of lock:\n",
- curr->comm, task_pid_nr(curr));
- print_lock(this);
- if (forwards)
- printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
- else
- printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
- print_lock_name(other);
- printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
-
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nthe first lock's dependencies:\n");
- print_lock_dependencies(this->class, 0);
-
- printk("\nthe second lock's dependencies:\n");
- print_lock_dependencies(other, 0);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Prove that in the forwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_forwards(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit bit, const char *irqclass)
-{
- int ret;
-
- find_usage_bit = bit;
- /* fills in <forwards_match> */
- ret = find_usage_forwards(this->class, 0);
- if (!ret || ret == 1)
- return ret;
-
- return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass);
-}
-
-/*
- * Prove that in the backwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_backwards(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit bit, const char *irqclass)
-{
- int ret;
-
- find_usage_bit = bit;
- /* fills in <backwards_match> */
- ret = find_usage_backwards(this->class, 0);
- if (!ret || ret == 1)
- return ret;
-
- return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
-}
-
-void print_irqtrace_events(struct task_struct *curr)
-{
- printk("irq event stamp: %u\n", curr->irq_events);
- printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
- print_ip_sym(curr->hardirq_enable_ip);
- printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
- print_ip_sym(curr->hardirq_disable_ip);
- printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
- print_ip_sym(curr->softirq_enable_ip);
- printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
- print_ip_sym(curr->softirq_disable_ip);
-}
-
-static int hardirq_verbose(struct lock_class *class)
-{
-#if HARDIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-static int softirq_verbose(struct lock_class *class)
-{
-#if SOFTIRQ_VERBOSE
- return class_filter(class);
-#endif
- return 0;
-}
-
-#define STRICT_READ_CHECKS 1
-
-static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- int ret = 1;
-
- switch(new_bit) {
- case LOCK_USED_IN_HARDIRQ:
- if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
- return 0;
- if (!valid_state(curr, this, new_bit,
- LOCK_ENABLED_HARDIRQS_READ))
- return 0;
- /*
- * just marked it hardirq-safe, check that this lock
- * took no hardirq-unsafe lock in the past:
- */
- if (!check_usage_forwards(curr, this,
- LOCK_ENABLED_HARDIRQS, "hard"))
- return 0;
-#if STRICT_READ_CHECKS
- /*
- * just marked it hardirq-safe, check that this lock
- * took no hardirq-unsafe-read lock in the past:
- */
- if (!check_usage_forwards(curr, this,
- LOCK_ENABLED_HARDIRQS_READ, "hard-read"))
- return 0;
-#endif
- if (hardirq_verbose(this->class))
- ret = 2;
- break;
- case LOCK_USED_IN_SOFTIRQ:
- if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
- return 0;
- if (!valid_state(curr, this, new_bit,
- LOCK_ENABLED_SOFTIRQS_READ))
- return 0;
- /*
- * just marked it softirq-safe, check that this lock
- * took no softirq-unsafe lock in the past:
- */
- if (!check_usage_forwards(curr, this,
- LOCK_ENABLED_SOFTIRQS, "soft"))
- return 0;
-#if STRICT_READ_CHECKS
- /*
- * just marked it softirq-safe, check that this lock
- * took no softirq-unsafe-read lock in the past:
- */
- if (!check_usage_forwards(curr, this,
- LOCK_ENABLED_SOFTIRQS_READ, "soft-read"))
- return 0;
-#endif
- if (softirq_verbose(this->class))
- ret = 2;
- break;
- case LOCK_USED_IN_HARDIRQ_READ:
- if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
- return 0;
- /*
- * just marked it hardirq-read-safe, check that this lock
- * took no hardirq-unsafe lock in the past:
- */
- if (!check_usage_forwards(curr, this,
- LOCK_ENABLED_HARDIRQS, "hard"))
- return 0;
- if (hardirq_verbose(this->class))
- ret = 2;
- break;
- case LOCK_USED_IN_SOFTIRQ_READ:
- if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
- return 0;
- /*
- * just marked it softirq-read-safe, check that this lock
- * took no softirq-unsafe lock in the past:
- */
- if (!check_usage_forwards(curr, this,
- LOCK_ENABLED_SOFTIRQS, "soft"))
- return 0;
- if (softirq_verbose(this->class))
- ret = 2;
- break;
- case LOCK_ENABLED_HARDIRQS:
- if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
- return 0;
- if (!valid_state(curr, this, new_bit,
- LOCK_USED_IN_HARDIRQ_READ))
- return 0;
- /*
- * just marked it hardirq-unsafe, check that no hardirq-safe
- * lock in the system ever took it in the past:
- */
- if (!check_usage_backwards(curr, this,
- LOCK_USED_IN_HARDIRQ, "hard"))
- return 0;
-#if STRICT_READ_CHECKS
- /*
- * just marked it hardirq-unsafe, check that no
- * hardirq-safe-read lock in the system ever took
- * it in the past:
- */
- if (!check_usage_backwards(curr, this,
- LOCK_USED_IN_HARDIRQ_READ, "hard-read"))
- return 0;
-#endif
- if (hardirq_verbose(this->class))
- ret = 2;
- break;
- case LOCK_ENABLED_SOFTIRQS:
- if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
- return 0;
- if (!valid_state(curr, this, new_bit,
- LOCK_USED_IN_SOFTIRQ_READ))
- return 0;
- /*
- * just marked it softirq-unsafe, check that no softirq-safe
- * lock in the system ever took it in the past:
- */
- if (!check_usage_backwards(curr, this,
- LOCK_USED_IN_SOFTIRQ, "soft"))
- return 0;
-#if STRICT_READ_CHECKS
- /*
- * just marked it softirq-unsafe, check that no
- * softirq-safe-read lock in the system ever took
- * it in the past:
- */
- if (!check_usage_backwards(curr, this,
- LOCK_USED_IN_SOFTIRQ_READ, "soft-read"))
- return 0;
-#endif
- if (softirq_verbose(this->class))
- ret = 2;
- break;
- case LOCK_ENABLED_HARDIRQS_READ:
- if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
- return 0;
-#if STRICT_READ_CHECKS
- /*
- * just marked it hardirq-read-unsafe, check that no
- * hardirq-safe lock in the system ever took it in the past:
- */
- if (!check_usage_backwards(curr, this,
- LOCK_USED_IN_HARDIRQ, "hard"))
- return 0;
-#endif
- if (hardirq_verbose(this->class))
- ret = 2;
- break;
- case LOCK_ENABLED_SOFTIRQS_READ:
- if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
- return 0;
-#if STRICT_READ_CHECKS
- /*
- * just marked it softirq-read-unsafe, check that no
- * softirq-safe lock in the system ever took it in the past:
- */
- if (!check_usage_backwards(curr, this,
- LOCK_USED_IN_SOFTIRQ, "soft"))
- return 0;
-#endif
- if (softirq_verbose(this->class))
- ret = 2;
- break;
- default:
- WARN_ON(1);
- break;
- }
-
- return ret;
-}
-
-/*
- * Mark all held locks with a usage bit:
- */
-static int
-mark_held_locks(struct task_struct *curr, int hardirq)
-{
- enum lock_usage_bit usage_bit;
- struct held_lock *hlock;
- int i;
-
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
-
- if (hardirq) {
- if (hlock->read)
- usage_bit = LOCK_ENABLED_HARDIRQS_READ;
- else
- usage_bit = LOCK_ENABLED_HARDIRQS;
- } else {
- if (hlock->read)
- usage_bit = LOCK_ENABLED_SOFTIRQS_READ;
- else
- usage_bit = LOCK_ENABLED_SOFTIRQS;
- }
- if (!mark_lock(curr, hlock, usage_bit))
- return 0;
- }
-
- return 1;
-}
-
-/*
- * Debugging helper: via this flag we know that we are in
- * 'early bootup code', and will warn about any invalid irqs-on event:
- */
-static int early_boot_irqs_enabled;
-
-void early_boot_irqs_off(void)
-{
- early_boot_irqs_enabled = 0;
-}
-
-void early_boot_irqs_on(void)
-{
- early_boot_irqs_enabled = 1;
-}
-
-/*
- * Hardirqs will be enabled:
- */
-void trace_hardirqs_on(void)
-{
- struct task_struct *curr = current;
- unsigned long ip;
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
- return;
-
- if (unlikely(curr->hardirqs_enabled)) {
- debug_atomic_inc(&redundant_hardirqs_on);
- return;
- }
- /* we'll do an OFF -> ON transition: */
- curr->hardirqs_enabled = 1;
- ip = (unsigned long) __builtin_return_address(0);
-
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
- if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
- return;
- /*
- * We are going to turn hardirqs on, so set the
- * usage bit for all held locks:
- */
- if (!mark_held_locks(curr, 1))
- return;
- /*
- * If we have softirqs enabled, then set the usage
- * bit for all held locks. (disabled hardirqs prevented
- * this bit from being set before)
- */
- if (curr->softirqs_enabled)
- if (!mark_held_locks(curr, 0))
- return;
-
- curr->hardirq_enable_ip = ip;
- curr->hardirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(&hardirqs_on_events);
-}
-
-EXPORT_SYMBOL(trace_hardirqs_on);
-
-/*
- * Hardirqs were disabled:
- */
-void trace_hardirqs_off(void)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks || current->lockdep_recursion))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->hardirqs_enabled) {
- /*
- * We have done an ON -> OFF transition:
- */
- curr->hardirqs_enabled = 0;
- curr->hardirq_disable_ip = _RET_IP_;
- curr->hardirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(&hardirqs_off_events);
- } else
- debug_atomic_inc(&redundant_hardirqs_off);
-}
-
-EXPORT_SYMBOL(trace_hardirqs_off);
-
-/*
- * Softirqs will be enabled:
- */
-void trace_softirqs_on(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->softirqs_enabled) {
- debug_atomic_inc(&redundant_softirqs_on);
- return;
- }
-
- /*
- * We'll do an OFF -> ON transition:
- */
- curr->softirqs_enabled = 1;
- curr->softirq_enable_ip = ip;
- curr->softirq_enable_event = ++curr->irq_events;
- debug_atomic_inc(&softirqs_on_events);
- /*
- * We are going to turn softirqs on, so set the
- * usage bit for all held locks, if hardirqs are
- * enabled too:
- */
- if (curr->hardirqs_enabled)
- mark_held_locks(curr, 0);
-}
-
-/*
- * Softirqs were disabled:
- */
-void trace_softirqs_off(unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (unlikely(!debug_locks))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return;
-
- if (curr->softirqs_enabled) {
- /*
- * We have done an ON -> OFF transition:
- */
- curr->softirqs_enabled = 0;
- curr->softirq_disable_ip = ip;
- curr->softirq_disable_event = ++curr->irq_events;
- debug_atomic_inc(&softirqs_off_events);
- DEBUG_LOCKS_WARN_ON(!softirq_count());
- } else
- debug_atomic_inc(&redundant_softirqs_off);
-}
-
-static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
-{
- /*
- * If non-trylock use in a hardirq or softirq context, then
- * mark the lock as used in these contexts:
- */
- if (!hlock->trylock) {
- if (hlock->read) {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_HARDIRQ_READ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock,
- LOCK_USED_IN_SOFTIRQ_READ))
- return 0;
- } else {
- if (curr->hardirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
- return 0;
- if (curr->softirq_context)
- if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
- return 0;
- }
- }
- if (!hlock->hardirqs_off) {
- if (hlock->read) {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS_READ))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS_READ))
- return 0;
- } else {
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_HARDIRQS))
- return 0;
- if (curr->softirqs_enabled)
- if (!mark_lock(curr, hlock,
- LOCK_ENABLED_SOFTIRQS))
- return 0;
- }
- }
-
- return 1;
-}
-
-static int separate_irq_context(struct task_struct *curr,
- struct held_lock *hlock)
-{
- unsigned int depth = curr->lockdep_depth;
-
- /*
- * Keep track of points where we cross into an interrupt context:
- */
- hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
- curr->softirq_context;
- if (depth) {
- struct held_lock *prev_hlock;
-
- prev_hlock = curr->held_locks + depth-1;
- /*
- * If we cross into another context, reset the
- * hash key (this also prevents the checking and the
- * adding of the dependency to 'prev'):
- */
- if (prev_hlock->irq_context != hlock->irq_context)
- return 1;
- }
- return 0;
-}
-
-#else
-
-static inline
-int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- WARN_ON(1);
- return 1;
-}
-
-static inline int mark_irqflags(struct task_struct *curr,
- struct held_lock *hlock)
-{
- return 1;
-}
-
-static inline int separate_irq_context(struct task_struct *curr,
- struct held_lock *hlock)
-{
- return 0;
-}
-
-#endif
-
-/*
- * Mark a lock with a usage bit, and validate the state transition:
- */
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
- enum lock_usage_bit new_bit)
-{
- unsigned int new_mask = 1 << new_bit, ret = 1;
-
- /*
- * If already set then do not dirty the cacheline,
- * nor do any checks:
- */
- if (likely(this->class->usage_mask & new_mask))
- return 1;
-
- if (!graph_lock())
- return 0;
- /*
- * Make sure we didnt race:
- */
- if (unlikely(this->class->usage_mask & new_mask)) {
- graph_unlock();
- return 1;
- }
-
- this->class->usage_mask |= new_mask;
-
- if (!save_trace(this->class->usage_traces + new_bit))
- return 0;
-
- switch (new_bit) {
- case LOCK_USED_IN_HARDIRQ:
- case LOCK_USED_IN_SOFTIRQ:
- case LOCK_USED_IN_HARDIRQ_READ:
- case LOCK_USED_IN_SOFTIRQ_READ:
- case LOCK_ENABLED_HARDIRQS:
- case LOCK_ENABLED_SOFTIRQS:
- case LOCK_ENABLED_HARDIRQS_READ:
- case LOCK_ENABLED_SOFTIRQS_READ:
- ret = mark_lock_irq(curr, this, new_bit);
- if (!ret)
- return 0;
- break;
- case LOCK_USED:
- /*
- * Add it to the global list of classes:
- */
- list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes);
- debug_atomic_dec(&nr_unused_locks);
- break;
- default:
- if (!debug_locks_off_graph_unlock())
- return 0;
- WARN_ON(1);
- return 0;
- }
-
- graph_unlock();
-
- /*
- * We must printk outside of the graph_lock:
- */
- if (ret == 2) {
- printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
- print_lock(this);
- print_irqtrace_events(curr);
- dump_stack();
- }
-
- return ret;
-}
-
-/*
- * Initialize a lock instance's lock-class mapping info:
- */
-void lockdep_init_map(struct lockdep_map *lock, const char *name,
- struct lock_class_key *key, int subclass)
-{
- if (unlikely(!debug_locks))
- return;
-
- if (DEBUG_LOCKS_WARN_ON(!key))
- return;
- if (DEBUG_LOCKS_WARN_ON(!name))
- return;
- /*
- * Sanity check, the lock-class key must be persistent:
- */
- if (!static_obj(key)) {
- printk("BUG: key %p not in .data!\n", key);
- DEBUG_LOCKS_WARN_ON(1);
- return;
- }
- lock->name = name;
- lock->key = key;
- lock->class_cache = NULL;
-#ifdef CONFIG_LOCK_STAT
- lock->cpu = raw_smp_processor_id();
-#endif
- if (subclass)
- register_lock_class(lock, subclass, 1);
-}
-
-EXPORT_SYMBOL_GPL(lockdep_init_map);
-
-/*
- * This gets called for every mutex_lock*()/spin_lock*() operation.
- * We maintain the dependency maps and validate the locking attempt:
- */
-static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
- int trylock, int read, int check, int hardirqs_off,
- unsigned long ip)
-{
- struct task_struct *curr = current;
- struct lock_class *class = NULL;
- struct held_lock *hlock;
- unsigned int depth, id;
- int chain_head = 0;
- u64 chain_key;
-
- if (!prove_locking)
- check = 1;
-
- if (unlikely(!debug_locks))
- return 0;
-
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
- debug_locks_off();
- printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
- printk("turning off the locking correctness validator.\n");
- return 0;
- }
-
- if (!subclass)
- class = lock->class_cache;
- /*
- * Not cached yet or subclass?
- */
- if (unlikely(!class)) {
- class = register_lock_class(lock, subclass, 0);
- if (!class)
- return 0;
- }
- debug_atomic_inc((atomic_t *)&class->ops);
- if (very_verbose(class)) {
- printk("\nacquire class [%p] %s", class->key, class->name);
- if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
- }
-
- /*
- * Add the lock to the list of currently held locks.
- * (we dont increase the depth just yet, up until the
- * dependency checks are done)
- */
- depth = curr->lockdep_depth;
- if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
- return 0;
-
- hlock = curr->held_locks + depth;
-
- hlock->class = class;
- hlock->acquire_ip = ip;
- hlock->instance = lock;
- hlock->trylock = trylock;
- hlock->read = read;
- hlock->check = check;
- hlock->hardirqs_off = hardirqs_off;
-#ifdef CONFIG_LOCK_STAT
- hlock->waittime_stamp = 0;
- hlock->holdtime_stamp = sched_clock();
-#endif
-
- if (check == 2 && !mark_irqflags(curr, hlock))
- return 0;
-
- /* mark it as used: */
- if (!mark_lock(curr, hlock, LOCK_USED))
- return 0;
-
- /*
- * Calculate the chain hash: it's the combined has of all the
- * lock keys along the dependency chain. We save the hash value
- * at every step so that we can get the current hash easily
- * after unlock. The chain hash is then used to cache dependency
- * results.
- *
- * The 'key ID' is what is the most compact key value to drive
- * the hash, not class->key.
- */
- id = class - lock_classes;
- if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
- return 0;
-
- chain_key = curr->curr_chain_key;
- if (!depth) {
- if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
- return 0;
- chain_head = 1;
- }
-
- hlock->prev_chain_key = chain_key;
- if (separate_irq_context(curr, hlock)) {
- chain_key = 0;
- chain_head = 1;
- }
- chain_key = iterate_chain_key(chain_key, id);
-
- if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
- return 0;
-
- curr->curr_chain_key = chain_key;
- curr->lockdep_depth++;
- check_chain_key(curr);
-#ifdef CONFIG_DEBUG_LOCKDEP
- if (unlikely(!debug_locks))
- return 0;
-#endif
- if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
- debug_locks_off();
- printk("BUG: MAX_LOCK_DEPTH too low!\n");
- printk("turning off the locking correctness validator.\n");
- return 0;
- }
-
- if (unlikely(curr->lockdep_depth > max_lockdep_depth))
- max_lockdep_depth = curr->lockdep_depth;
-
- return 1;
-}
-
-static int
-print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
-{
- if (!debug_locks_off())
- return 0;
- if (debug_locks_silent)
- return 0;
-
- printk("\n=====================================\n");
- printk( "[ BUG: bad unlock balance detected! ]\n");
- printk( "-------------------------------------\n");
- printk("%s/%d is trying to release lock (",
- curr->comm, task_pid_nr(curr));
- print_lockdep_cache(lock);
- printk(") at:\n");
- print_ip_sym(ip);
- printk("but there are no more locks to release!\n");
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-/*
- * Common debugging checks for both nested and non-nested unlock:
- */
-static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
-{
- if (unlikely(!debug_locks))
- return 0;
- if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
- return 0;
-
- if (curr->lockdep_depth <= 0)
- return print_unlock_inbalance_bug(curr, lock, ip);
-
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks in a
- * potentially non-nested (out of order) manner. This is a
- * relatively rare operation, as all the unlock APIs default
- * to nested mode (which uses lock_release()):
- */
-static int
-lock_release_non_nested(struct task_struct *curr,
- struct lockdep_map *lock, unsigned long ip)
-{
- struct held_lock *hlock, *prev_hlock;
- unsigned int depth;
- int i;
-
- /*
- * Check whether the lock exists in the current stack
- * of held locks:
- */
- depth = curr->lockdep_depth;
- if (DEBUG_LOCKS_WARN_ON(!depth))
- return 0;
-
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (hlock->instance == lock)
- goto found_it;
- prev_hlock = hlock;
- }
- return print_unlock_inbalance_bug(curr, lock, ip);
-
-found_it:
- lock_release_holdtime(hlock);
-
- /*
- * We have the right lock to unlock, 'hlock' points to it.
- * Now we remove it from the stack, and add back the other
- * entries (if any), recalculating the hash along the way:
- */
- curr->lockdep_depth = i;
- curr->curr_chain_key = hlock->prev_chain_key;
-
- for (i++; i < depth; i++) {
- hlock = curr->held_locks + i;
- if (!__lock_acquire(hlock->instance,
- hlock->class->subclass, hlock->trylock,
- hlock->read, hlock->check, hlock->hardirqs_off,
- hlock->acquire_ip))
- return 0;
- }
-
- if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
- return 0;
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static int lock_release_nested(struct task_struct *curr,
- struct lockdep_map *lock, unsigned long ip)
-{
- struct held_lock *hlock;
- unsigned int depth;
-
- /*
- * Pop off the top of the lock stack:
- */
- depth = curr->lockdep_depth - 1;
- hlock = curr->held_locks + depth;
-
- /*
- * Is the unlock non-nested:
- */
- if (hlock->instance != lock)
- return lock_release_non_nested(curr, lock, ip);
- curr->lockdep_depth--;
-
- if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
- return 0;
-
- curr->curr_chain_key = hlock->prev_chain_key;
-
- lock_release_holdtime(hlock);
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- hlock->prev_chain_key = 0;
- hlock->class = NULL;
- hlock->acquire_ip = 0;
- hlock->irq_context = 0;
-#endif
- return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static void
-__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
-{
- struct task_struct *curr = current;
-
- if (!check_unlock(curr, lock, ip))
- return;
-
- if (nested) {
- if (!lock_release_nested(curr, lock, ip))
- return;
- } else {
- if (!lock_release_non_nested(curr, lock, ip))
- return;
- }
-
- check_chain_key(curr);
-}
-
-/*
- * Check whether we follow the irq-flags state precisely:
- */
-static void check_flags(unsigned long flags)
-{
-#if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS)
- if (!debug_locks)
- return;
-
- if (irqs_disabled_flags(flags))
- DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled);
- else
- DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled);
-
- /*
- * We dont accurately track softirq state in e.g.
- * hardirq contexts (such as on 4KSTACKS), so only
- * check if not in hardirq contexts:
- */
- if (!hardirq_count()) {
- if (softirq_count())
- DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
- else
- DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
- }
-
- if (!debug_locks)
- print_irqtrace_events(current);
-#endif
-}
-
-/*
- * We are not always called with irqs disabled - do that here,
- * and also avoid lockdep recursion:
- */
-void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
- int trylock, int read, int check, unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(!lock_stat && !prove_locking))
- return;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
-
- current->lockdep_recursion = 1;
- __lock_acquire(lock, subclass, trylock, read, check,
- irqs_disabled_flags(flags), ip);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-
-EXPORT_SYMBOL_GPL(lock_acquire);
-
-void lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(!lock_stat && !prove_locking))
- return;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- __lock_release(lock, nested, ip);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-
-EXPORT_SYMBOL_GPL(lock_release);
-
-#ifdef CONFIG_LOCK_STAT
-static int
-print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
- unsigned long ip)
-{
- if (!debug_locks_off())
- return 0;
- if (debug_locks_silent)
- return 0;
-
- printk("\n=================================\n");
- printk( "[ BUG: bad contention detected! ]\n");
- printk( "---------------------------------\n");
- printk("%s/%d is trying to contend lock (",
- curr->comm, task_pid_nr(curr));
- print_lockdep_cache(lock);
- printk(") at:\n");
- print_ip_sym(ip);
- printk("but there are no locks held!\n");
- printk("\nother info that might help us debug this:\n");
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-
- return 0;
-}
-
-static void
-__lock_contended(struct lockdep_map *lock, unsigned long ip)
-{
- struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
- struct lock_class_stats *stats;
- unsigned int depth;
- int i, point;
-
- depth = curr->lockdep_depth;
- if (DEBUG_LOCKS_WARN_ON(!depth))
- return;
-
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (hlock->instance == lock)
- goto found_it;
- prev_hlock = hlock;
- }
- print_lock_contention_bug(curr, lock, ip);
- return;
-
-found_it:
- hlock->waittime_stamp = sched_clock();
-
- point = lock_contention_point(hlock->class, ip);
-
- stats = get_lock_stats(hlock->class);
- if (point < ARRAY_SIZE(stats->contention_point))
- stats->contention_point[i]++;
- if (lock->cpu != smp_processor_id())
- stats->bounces[bounce_contended + !!hlock->read]++;
- put_lock_stats(stats);
-}
-
-static void
-__lock_acquired(struct lockdep_map *lock)
-{
- struct task_struct *curr = current;
- struct held_lock *hlock, *prev_hlock;
- struct lock_class_stats *stats;
- unsigned int depth;
- u64 now;
- s64 waittime = 0;
- int i, cpu;
-
- depth = curr->lockdep_depth;
- if (DEBUG_LOCKS_WARN_ON(!depth))
- return;
-
- prev_hlock = NULL;
- for (i = depth-1; i >= 0; i--) {
- hlock = curr->held_locks + i;
- /*
- * We must not cross into another context:
- */
- if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
- break;
- if (hlock->instance == lock)
- goto found_it;
- prev_hlock = hlock;
- }
- print_lock_contention_bug(curr, lock, _RET_IP_);
- return;
-
-found_it:
- cpu = smp_processor_id();
- if (hlock->waittime_stamp) {
- now = sched_clock();
- waittime = now - hlock->waittime_stamp;
- hlock->holdtime_stamp = now;
- }
-
- stats = get_lock_stats(hlock->class);
- if (waittime) {
- if (hlock->read)
- lock_time_inc(&stats->read_waittime, waittime);
- else
- lock_time_inc(&stats->write_waittime, waittime);
- }
- if (lock->cpu != cpu)
- stats->bounces[bounce_acquired + !!hlock->read]++;
- put_lock_stats(stats);
-
- lock->cpu = cpu;
-}
-
-void lock_contended(struct lockdep_map *lock, unsigned long ip)
-{
- unsigned long flags;
-
- if (unlikely(!lock_stat))
- return;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- __lock_contended(lock, ip);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_contended);
-
-void lock_acquired(struct lockdep_map *lock)
-{
- unsigned long flags;
-
- if (unlikely(!lock_stat))
- return;
-
- if (unlikely(current->lockdep_recursion))
- return;
-
- raw_local_irq_save(flags);
- check_flags(flags);
- current->lockdep_recursion = 1;
- __lock_acquired(lock);
- current->lockdep_recursion = 0;
- raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_acquired);
-#endif
-
-/*
- * Used by the testsuite, sanitize the validator state
- * after a simulated failure:
- */
-
-void lockdep_reset(void)
-{
- unsigned long flags;
- int i;
-
- raw_local_irq_save(flags);
- current->curr_chain_key = 0;
- current->lockdep_depth = 0;
- current->lockdep_recursion = 0;
- memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
- nr_hardirq_chains = 0;
- nr_softirq_chains = 0;
- nr_process_chains = 0;
- debug_locks = 1;
- for (i = 0; i < CHAINHASH_SIZE; i++)
- INIT_LIST_HEAD(chainhash_table + i);
- raw_local_irq_restore(flags);
-}
-
-static void zap_class(struct lock_class *class)
-{
- int i;
-
- /*
- * Remove all dependencies this lock is
- * involved in:
- */
- for (i = 0; i < nr_list_entries; i++) {
- if (list_entries[i].class == class)
- list_del_rcu(&list_entries[i].entry);
- }
- /*
- * Unhash the class and remove it from the all_lock_classes list:
- */
- list_del_rcu(&class->hash_entry);
- list_del_rcu(&class->lock_entry);
-
-}
-
-static inline int within(void *addr, void *start, unsigned long size)
-{
- return addr >= start && addr < start + size;
-}
-
-void lockdep_free_key_range(void *start, unsigned long size)
-{
- struct lock_class *class, *next;
- struct list_head *head;
- unsigned long flags;
- int i;
-
- raw_local_irq_save(flags);
- graph_lock();
-
- /*
- * Unhash all classes that were created by this module:
- */
- for (i = 0; i < CLASSHASH_SIZE; i++) {
- head = classhash_table + i;
- if (list_empty(head))
- continue;
- list_for_each_entry_safe(class, next, head, hash_entry)
- if (within(class->key, start, size))
- zap_class(class);
- }
-
- graph_unlock();
- raw_local_irq_restore(flags);
-}
-
-void lockdep_reset_lock(struct lockdep_map *lock)
-{
- struct lock_class *class, *next;
- struct list_head *head;
- unsigned long flags;
- int i, j;
-
- raw_local_irq_save(flags);
-
- /*
- * Remove all classes this lock might have:
- */
- for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
- /*
- * If the class exists we look it up and zap it:
- */
- class = look_up_lock_class(lock, j);
- if (class)
- zap_class(class);
- }
- /*
- * Debug check: in the end all mapped classes should
- * be gone.
- */
- graph_lock();
- for (i = 0; i < CLASSHASH_SIZE; i++) {
- head = classhash_table + i;
- if (list_empty(head))
- continue;
- list_for_each_entry_safe(class, next, head, hash_entry) {
- if (unlikely(class == lock->class_cache)) {
- if (debug_locks_off_graph_unlock())
- WARN_ON(1);
- goto out_restore;
- }
- }
- }
- graph_unlock();
-
-out_restore:
- raw_local_irq_restore(flags);
-}
-
-void lockdep_init(void)
-{
- int i;
-
- /*
- * Some architectures have their own start_kernel()
- * code which calls lockdep_init(), while we also
- * call lockdep_init() from the start_kernel() itself,
- * and we want to initialize the hashes only once:
- */
- if (lockdep_initialized)
- return;
-
- for (i = 0; i < CLASSHASH_SIZE; i++)
- INIT_LIST_HEAD(classhash_table + i);
-
- for (i = 0; i < CHAINHASH_SIZE; i++)
- INIT_LIST_HEAD(chainhash_table + i);
-
- lockdep_initialized = 1;
-}
-
-void __init lockdep_info(void)
-{
- printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
-
- printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
- printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
- printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
- printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
- printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
- printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
- printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
-
- printk(" memory used by lock dependency info: %lu kB\n",
- (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
- sizeof(struct list_head) * CLASSHASH_SIZE +
- sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
- sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
- sizeof(struct list_head) * CHAINHASH_SIZE) / 1024);
-
- printk(" per task-struct memory footprint: %lu bytes\n",
- sizeof(struct held_lock) * MAX_LOCK_DEPTH);
-
-#ifdef CONFIG_DEBUG_LOCKDEP
- if (lockdep_init_error) {
- printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
- printk("Call stack leading to lockdep invocation was:\n");
- print_stack_trace(&lockdep_init_trace, 0);
- }
-#endif
-}
-
-static inline int in_range(const void *start, const void *addr, const void *end)
-{
- return addr >= start && addr <= end;
-}
-
-static void
-print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
- const void *mem_to, struct held_lock *hlock)
-{
- if (!debug_locks_off())
- return;
- if (debug_locks_silent)
- return;
-
- printk("\n=========================\n");
- printk( "[ BUG: held lock freed! ]\n");
- printk( "-------------------------\n");
- printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
- curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
- print_lock(hlock);
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-}
-
-/*
- * Called when kernel memory is freed (or unmapped), or if a lock
- * is destroyed or reinitialized - this code checks whether there is
- * any held lock in the memory range of <from> to <to>:
- */
-void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
-{
- const void *mem_to = mem_from + mem_len, *lock_from, *lock_to;
- struct task_struct *curr = current;
- struct held_lock *hlock;
- unsigned long flags;
- int i;
-
- if (unlikely(!debug_locks))
- return;
-
- local_irq_save(flags);
- for (i = 0; i < curr->lockdep_depth; i++) {
- hlock = curr->held_locks + i;
-
- lock_from = (void *)hlock->instance;
- lock_to = (void *)(hlock->instance + 1);
-
- if (!in_range(mem_from, lock_from, mem_to) &&
- !in_range(mem_from, lock_to, mem_to))
- continue;
-
- print_freed_lock_bug(curr, mem_from, mem_to, hlock);
- break;
- }
- local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
-
-static void print_held_locks_bug(struct task_struct *curr)
-{
- if (!debug_locks_off())
- return;
- if (debug_locks_silent)
- return;
-
- printk("\n=====================================\n");
- printk( "[ BUG: lock held at task exit time! ]\n");
- printk( "-------------------------------------\n");
- printk("%s/%d is exiting with locks still held!\n",
- curr->comm, task_pid_nr(curr));
- lockdep_print_held_locks(curr);
-
- printk("\nstack backtrace:\n");
- dump_stack();
-}
-
-void debug_check_no_locks_held(struct task_struct *task)
-{
- if (unlikely(task->lockdep_depth > 0))
- print_held_locks_bug(task);
-}
-
-void debug_show_all_locks(void)
-{
- struct task_struct *g, *p;
- int count = 10;
- int unlock = 1;
-
- if (unlikely(!debug_locks)) {
- printk("INFO: lockdep is turned off.\n");
- return;
- }
- printk("\nShowing all locks held in the system:\n");
-
- /*
- * Here we try to get the tasklist_lock as hard as possible,
- * if not successful after 2 seconds we ignore it (but keep
- * trying). This is to enable a debug printout even if a
- * tasklist_lock-holding task deadlocks or crashes.
- */
-retry:
- if (!read_trylock(&tasklist_lock)) {
- if (count == 10)
- printk("hm, tasklist_lock locked, retrying... ");
- if (count) {
- count--;
- printk(" #%d", 10-count);
- mdelay(200);
- goto retry;
- }
- printk(" ignoring it.\n");
- unlock = 0;
- }
- if (count != 10)
- printk(" locked it.\n");
-
- do_each_thread(g, p) {
- if (p->lockdep_depth)
- lockdep_print_held_locks(p);
- if (!unlock)
- if (read_trylock(&tasklist_lock))
- unlock = 1;
- } while_each_thread(g, p);
-
- printk("\n");
- printk("=============================================\n\n");
-
- if (unlock)
- read_unlock(&tasklist_lock);
-}
-
-EXPORT_SYMBOL_GPL(debug_show_all_locks);
-
-void debug_show_held_locks(struct task_struct *task)
-{
- if (unlikely(!debug_locks)) {
- printk("INFO: lockdep is turned off.\n");
- return;
- }
- lockdep_print_held_locks(task);
-}
-
-EXPORT_SYMBOL_GPL(debug_show_held_locks);
-
-void lockdep_sys_exit(void)
-{
- struct task_struct *curr = current;
-
- if (unlikely(curr->lockdep_depth)) {
- if (!debug_locks_off())
- return;
- printk("\n================================================\n");
- printk( "[ BUG: lock held when returning to user space! ]\n");
- printk( "------------------------------------------------\n");
- printk("%s/%d is leaving the kernel with locks still held!\n",
- curr->comm, curr->pid);
- lockdep_print_held_locks(curr);
- }
-}
Index: linux-2.6-lttng.stable/kernel/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/Makefile 2007-10-29 09:52:13.000000000 -0400
+++ linux-2.6-lttng.stable/kernel/Makefile 2007-10-29 09:52:35.000000000 -0400
@@ -15,10 +15,6 @@ obj-$(CONFIG_SYSCTL) += sysctl_check.o
obj-$(CONFIG_STACKTRACE) += stacktrace.o
obj-y += time/
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
-obj-$(CONFIG_LOCKDEP) += lockdep.o
-ifeq ($(CONFIG_PROC_FS),y)
-obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
-endif
obj-$(CONFIG_FUTEX) += futex.o
ifeq ($(CONFIG_COMPAT),y)
obj-$(CONFIG_FUTEX) += futex_compat.o
Index: linux-2.6-lttng.stable/instrumentation/lockdep_internals.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/instrumentation/lockdep_internals.h 2007-10-29 09:52:35.000000000 -0400
@@ -0,0 +1,78 @@
+/*
+ * kernel/lockdep_internals.h
+ *
+ * Runtime locking correctness validator
+ *
+ * lockdep subsystem internal functions and variables.
+ */
+
+/*
+ * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
+ * we track.
+ *
+ * We use the per-lock dependency maps in two ways: we grow it by adding
+ * every to-be-taken lock to all currently held lock's own dependency
+ * table (if it's not there yet), and we check it for lock order
+ * conflicts and deadlocks.
+ */
+#define MAX_LOCKDEP_ENTRIES 8192UL
+
+#define MAX_LOCKDEP_KEYS_BITS 11
+#define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
+
+#define MAX_LOCKDEP_CHAINS_BITS 14
+#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
+
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the hash_lock.
+ */
+#define MAX_STACK_TRACE_ENTRIES 262144UL
+
+extern struct list_head all_lock_classes;
+
+extern void
+get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
+
+extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
+
+extern unsigned long nr_lock_classes;
+extern unsigned long nr_list_entries;
+extern unsigned long nr_lock_chains;
+extern unsigned long nr_stack_trace_entries;
+
+extern unsigned int nr_hardirq_chains;
+extern unsigned int nr_softirq_chains;
+extern unsigned int nr_process_chains;
+extern unsigned int max_lockdep_depth;
+extern unsigned int max_recursion_depth;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+/*
+ * Various lockdep statistics:
+ */
+extern atomic_t chain_lookup_hits;
+extern atomic_t chain_lookup_misses;
+extern atomic_t hardirqs_on_events;
+extern atomic_t hardirqs_off_events;
+extern atomic_t redundant_hardirqs_on;
+extern atomic_t redundant_hardirqs_off;
+extern atomic_t softirqs_on_events;
+extern atomic_t softirqs_off_events;
+extern atomic_t redundant_softirqs_on;
+extern atomic_t redundant_softirqs_off;
+extern atomic_t nr_unused_locks;
+extern atomic_t nr_cyclic_checks;
+extern atomic_t nr_cyclic_check_recursions;
+extern atomic_t nr_find_usage_forwards_checks;
+extern atomic_t nr_find_usage_forwards_recursions;
+extern atomic_t nr_find_usage_backwards_checks;
+extern atomic_t nr_find_usage_backwards_recursions;
+# define debug_atomic_inc(ptr) atomic_inc(ptr)
+# define debug_atomic_dec(ptr) atomic_dec(ptr)
+# define debug_atomic_read(ptr) atomic_read(ptr)
+#else
+# define debug_atomic_inc(ptr) do { } while (0)
+# define debug_atomic_dec(ptr) do { } while (0)
+# define debug_atomic_read(ptr) 0
+#endif
Index: linux-2.6-lttng.stable/instrumentation/lockdep_proc.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/instrumentation/lockdep_proc.c 2007-10-29 09:52:35.000000000 -0400
@@ -0,0 +1,683 @@
+/*
+ * kernel/lockdep_proc.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <[email protected]>
+ * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <[email protected]>
+ *
+ * Code for /proc/lockdep and /proc/lockdep_stats:
+ *
+ */
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/debug_locks.h>
+#include <linux/vmalloc.h>
+#include <linux/sort.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+
+#include "lockdep_internals.h"
+
+static void *l_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ struct lock_class *class;
+
+ (*pos)++;
+
+ if (v == SEQ_START_TOKEN)
+ class = m->private;
+ else {
+ class = v;
+
+ if (class->lock_entry.next != &all_lock_classes)
+ class = list_entry(class->lock_entry.next,
+ struct lock_class, lock_entry);
+ else
+ class = NULL;
+ }
+
+ return class;
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+ struct lock_class *class;
+ loff_t i = 0;
+
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ if (++i == *pos)
+ return class;
+ }
+ return NULL;
+}
+
+static void l_stop(struct seq_file *m, void *v)
+{
+}
+
+static unsigned long count_forward_deps(struct lock_class *class)
+{
+ struct lock_list *entry;
+ unsigned long ret = 1;
+
+ /*
+ * Recurse this class's dependency list:
+ */
+ list_for_each_entry(entry, &class->locks_after, entry)
+ ret += count_forward_deps(entry->class);
+
+ return ret;
+}
+
+static unsigned long count_backward_deps(struct lock_class *class)
+{
+ struct lock_list *entry;
+ unsigned long ret = 1;
+
+ /*
+ * Recurse this class's dependency list:
+ */
+ list_for_each_entry(entry, &class->locks_before, entry)
+ ret += count_backward_deps(entry->class);
+
+ return ret;
+}
+
+static void print_name(struct seq_file *m, struct lock_class *class)
+{
+ char str[128];
+ const char *name = class->name;
+
+ if (!name) {
+ name = __get_key_name(class->key, str);
+ seq_printf(m, "%s", name);
+ } else{
+ seq_printf(m, "%s", name);
+ if (class->name_version > 1)
+ seq_printf(m, "#%d", class->name_version);
+ if (class->subclass)
+ seq_printf(m, "/%d", class->subclass);
+ }
+}
+
+static int l_show(struct seq_file *m, void *v)
+{
+ unsigned long nr_forward_deps, nr_backward_deps;
+ struct lock_class *class = v;
+ struct lock_list *entry;
+ char c1, c2, c3, c4;
+
+ if (v == SEQ_START_TOKEN) {
+ seq_printf(m, "all lock classes:\n");
+ return 0;
+ }
+
+ seq_printf(m, "%p", class->key);
+#ifdef CONFIG_DEBUG_LOCKDEP
+ seq_printf(m, " OPS:%8ld", class->ops);
+#endif
+ nr_forward_deps = count_forward_deps(class);
+ seq_printf(m, " FD:%5ld", nr_forward_deps);
+
+ nr_backward_deps = count_backward_deps(class);
+ seq_printf(m, " BD:%5ld", nr_backward_deps);
+
+ get_usage_chars(class, &c1, &c2, &c3, &c4);
+ seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
+
+ seq_printf(m, ": ");
+ print_name(m, class);
+ seq_puts(m, "\n");
+
+ list_for_each_entry(entry, &class->locks_after, entry) {
+ if (entry->distance == 1) {
+ seq_printf(m, " -> [%p] ", entry->class);
+ print_name(m, entry->class);
+ seq_puts(m, "\n");
+ }
+ }
+ seq_puts(m, "\n");
+
+ return 0;
+}
+
+static const struct seq_operations lockdep_ops = {
+ .start = l_start,
+ .next = l_next,
+ .stop = l_stop,
+ .show = l_show,
+};
+
+static int lockdep_open(struct inode *inode, struct file *file)
+{
+ int res = seq_open(file, &lockdep_ops);
+ if (!res) {
+ struct seq_file *m = file->private_data;
+
+ if (!list_empty(&all_lock_classes))
+ m->private = list_entry(all_lock_classes.next,
+ struct lock_class, lock_entry);
+ else
+ m->private = NULL;
+ }
+ return res;
+}
+
+static const struct file_operations proc_lockdep_operations = {
+ .open = lockdep_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+
+static void lockdep_stats_debug_show(struct seq_file *m)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+ unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
+ hi2 = debug_atomic_read(&hardirqs_off_events),
+ hr1 = debug_atomic_read(&redundant_hardirqs_on),
+ hr2 = debug_atomic_read(&redundant_hardirqs_off),
+ si1 = debug_atomic_read(&softirqs_on_events),
+ si2 = debug_atomic_read(&softirqs_off_events),
+ sr1 = debug_atomic_read(&redundant_softirqs_on),
+ sr2 = debug_atomic_read(&redundant_softirqs_off);
+
+ seq_printf(m, " chain lookup misses: %11u\n",
+ debug_atomic_read(&chain_lookup_misses));
+ seq_printf(m, " chain lookup hits: %11u\n",
+ debug_atomic_read(&chain_lookup_hits));
+ seq_printf(m, " cyclic checks: %11u\n",
+ debug_atomic_read(&nr_cyclic_checks));
+ seq_printf(m, " cyclic-check recursions: %11u\n",
+ debug_atomic_read(&nr_cyclic_check_recursions));
+ seq_printf(m, " find-mask forwards checks: %11u\n",
+ debug_atomic_read(&nr_find_usage_forwards_checks));
+ seq_printf(m, " find-mask forwards recursions: %11u\n",
+ debug_atomic_read(&nr_find_usage_forwards_recursions));
+ seq_printf(m, " find-mask backwards checks: %11u\n",
+ debug_atomic_read(&nr_find_usage_backwards_checks));
+ seq_printf(m, " find-mask backwards recursions:%11u\n",
+ debug_atomic_read(&nr_find_usage_backwards_recursions));
+
+ seq_printf(m, " hardirq on events: %11u\n", hi1);
+ seq_printf(m, " hardirq off events: %11u\n", hi2);
+ seq_printf(m, " redundant hardirq ons: %11u\n", hr1);
+ seq_printf(m, " redundant hardirq offs: %11u\n", hr2);
+ seq_printf(m, " softirq on events: %11u\n", si1);
+ seq_printf(m, " softirq off events: %11u\n", si2);
+ seq_printf(m, " redundant softirq ons: %11u\n", sr1);
+ seq_printf(m, " redundant softirq offs: %11u\n", sr2);
+#endif
+}
+
+static int lockdep_stats_show(struct seq_file *m, void *v)
+{
+ struct lock_class *class;
+ unsigned long nr_unused = 0, nr_uncategorized = 0,
+ nr_irq_safe = 0, nr_irq_unsafe = 0,
+ nr_softirq_safe = 0, nr_softirq_unsafe = 0,
+ nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
+ nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
+ nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
+ nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
+ sum_forward_deps = 0, factor = 0;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+
+ if (class->usage_mask == 0)
+ nr_unused++;
+ if (class->usage_mask == LOCKF_USED)
+ nr_uncategorized++;
+ if (class->usage_mask & LOCKF_USED_IN_IRQ)
+ nr_irq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_IRQS)
+ nr_irq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
+ nr_softirq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
+ nr_softirq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
+ nr_hardirq_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
+ nr_hardirq_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
+ nr_irq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
+ nr_irq_read_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
+ nr_softirq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
+ nr_softirq_read_unsafe++;
+ if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
+ nr_hardirq_read_safe++;
+ if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
+ nr_hardirq_read_unsafe++;
+
+ sum_forward_deps += count_forward_deps(class);
+ }
+#ifdef CONFIG_DEBUG_LOCKDEP
+ DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
+#endif
+ seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
+ nr_lock_classes, MAX_LOCKDEP_KEYS);
+ seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
+ nr_list_entries, MAX_LOCKDEP_ENTRIES);
+ seq_printf(m, " indirect dependencies: %11lu\n",
+ sum_forward_deps);
+
+ /*
+ * Total number of dependencies:
+ *
+ * All irq-safe locks may nest inside irq-unsafe locks,
+ * plus all the other known dependencies:
+ */
+ seq_printf(m, " all direct dependencies: %11lu\n",
+ nr_irq_unsafe * nr_irq_safe +
+ nr_hardirq_unsafe * nr_hardirq_safe +
+ nr_list_entries);
+
+ /*
+ * Estimated factor between direct and indirect
+ * dependencies:
+ */
+ if (nr_list_entries)
+ factor = sum_forward_deps / nr_list_entries;
+
+#ifdef CONFIG_PROVE_LOCKING
+ seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
+ nr_lock_chains, MAX_LOCKDEP_CHAINS);
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+ seq_printf(m, " in-hardirq chains: %11u\n",
+ nr_hardirq_chains);
+ seq_printf(m, " in-softirq chains: %11u\n",
+ nr_softirq_chains);
+#endif
+ seq_printf(m, " in-process chains: %11u\n",
+ nr_process_chains);
+ seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
+ nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
+ seq_printf(m, " combined max dependencies: %11u\n",
+ (nr_hardirq_chains + 1) *
+ (nr_softirq_chains + 1) *
+ (nr_process_chains + 1)
+ );
+ seq_printf(m, " hardirq-safe locks: %11lu\n",
+ nr_hardirq_safe);
+ seq_printf(m, " hardirq-unsafe locks: %11lu\n",
+ nr_hardirq_unsafe);
+ seq_printf(m, " softirq-safe locks: %11lu\n",
+ nr_softirq_safe);
+ seq_printf(m, " softirq-unsafe locks: %11lu\n",
+ nr_softirq_unsafe);
+ seq_printf(m, " irq-safe locks: %11lu\n",
+ nr_irq_safe);
+ seq_printf(m, " irq-unsafe locks: %11lu\n",
+ nr_irq_unsafe);
+
+ seq_printf(m, " hardirq-read-safe locks: %11lu\n",
+ nr_hardirq_read_safe);
+ seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
+ nr_hardirq_read_unsafe);
+ seq_printf(m, " softirq-read-safe locks: %11lu\n",
+ nr_softirq_read_safe);
+ seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
+ nr_softirq_read_unsafe);
+ seq_printf(m, " irq-read-safe locks: %11lu\n",
+ nr_irq_read_safe);
+ seq_printf(m, " irq-read-unsafe locks: %11lu\n",
+ nr_irq_read_unsafe);
+
+ seq_printf(m, " uncategorized locks: %11lu\n",
+ nr_uncategorized);
+ seq_printf(m, " unused locks: %11lu\n",
+ nr_unused);
+ seq_printf(m, " max locking depth: %11u\n",
+ max_lockdep_depth);
+ seq_printf(m, " max recursion depth: %11u\n",
+ max_recursion_depth);
+ lockdep_stats_debug_show(m);
+ seq_printf(m, " debug_locks: %11u\n",
+ debug_locks);
+
+ return 0;
+}
+
+static int lockdep_stats_open(struct inode *inode, struct file *file)
+{
+ return single_open(file, lockdep_stats_show, NULL);
+}
+
+static const struct file_operations proc_lockdep_stats_operations = {
+ .open = lockdep_stats_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+#ifdef CONFIG_LOCK_STAT
+
+struct lock_stat_data {
+ struct lock_class *class;
+ struct lock_class_stats stats;
+};
+
+struct lock_stat_seq {
+ struct lock_stat_data *iter;
+ struct lock_stat_data *iter_end;
+ struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
+};
+
+/*
+ * sort on absolute number of contentions
+ */
+static int lock_stat_cmp(const void *l, const void *r)
+{
+ const struct lock_stat_data *dl = l, *dr = r;
+ unsigned long nl, nr;
+
+ nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
+ nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
+
+ return nr - nl;
+}
+
+static void seq_line(struct seq_file *m, char c, int offset, int length)
+{
+ int i;
+
+ for (i = 0; i < offset; i++)
+ seq_puts(m, " ");
+ for (i = 0; i < length; i++)
+ seq_printf(m, "%c", c);
+ seq_puts(m, "\n");
+}
+
+static void snprint_time(char *buf, size_t bufsiz, s64 nr)
+{
+ unsigned long rem;
+
+ rem = do_div(nr, 1000); /* XXX: do_div_signed */
+ snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
+}
+
+static void seq_time(struct seq_file *m, s64 time)
+{
+ char num[15];
+
+ snprint_time(num, sizeof(num), time);
+ seq_printf(m, " %14s", num);
+}
+
+static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
+{
+ seq_printf(m, "%14lu", lt->nr);
+ seq_time(m, lt->min);
+ seq_time(m, lt->max);
+ seq_time(m, lt->total);
+}
+
+static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
+{
+ char name[39];
+ struct lock_class *class;
+ struct lock_class_stats *stats;
+ int i, namelen;
+
+ class = data->class;
+ stats = &data->stats;
+
+ namelen = 38;
+ if (class->name_version > 1)
+ namelen -= 2; /* XXX truncates versions > 9 */
+ if (class->subclass)
+ namelen -= 2;
+
+ if (!class->name) {
+ char str[KSYM_NAME_LEN];
+ const char *key_name;
+
+ key_name = __get_key_name(class->key, str);
+ snprintf(name, namelen, "%s", key_name);
+ } else {
+ snprintf(name, namelen, "%s", class->name);
+ }
+ namelen = strlen(name);
+ if (class->name_version > 1) {
+ snprintf(name+namelen, 3, "#%d", class->name_version);
+ namelen += 2;
+ }
+ if (class->subclass) {
+ snprintf(name+namelen, 3, "/%d", class->subclass);
+ namelen += 2;
+ }
+
+ if (stats->write_holdtime.nr) {
+ if (stats->read_holdtime.nr)
+ seq_printf(m, "%38s-W:", name);
+ else
+ seq_printf(m, "%40s:", name);
+
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
+ seq_lock_time(m, &stats->write_waittime);
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
+ seq_lock_time(m, &stats->write_holdtime);
+ seq_puts(m, "\n");
+ }
+
+ if (stats->read_holdtime.nr) {
+ seq_printf(m, "%38s-R:", name);
+ seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
+ seq_lock_time(m, &stats->read_waittime);
+ seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
+ seq_lock_time(m, &stats->read_holdtime);
+ seq_puts(m, "\n");
+ }
+
+ if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
+ return;
+
+ if (stats->read_holdtime.nr)
+ namelen += 2;
+
+ for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
+ char sym[KSYM_SYMBOL_LEN];
+ char ip[32];
+
+ if (class->contention_point[i] == 0)
+ break;
+
+ if (!i)
+ seq_line(m, '-', 40-namelen, namelen);
+
+ sprint_symbol(sym, class->contention_point[i]);
+ snprintf(ip, sizeof(ip), "[<%p>]",
+ (void *)class->contention_point[i]);
+ seq_printf(m, "%40s %14lu %29s %s\n", name,
+ stats->contention_point[i],
+ ip, sym);
+ }
+ if (i) {
+ seq_puts(m, "\n");
+ seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
+ seq_puts(m, "\n");
+ }
+}
+
+static void seq_header(struct seq_file *m)
+{
+ seq_printf(m, "lock_stat version 0.2\n");
+ seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
+ seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
+ "%14s %14s\n",
+ "class name",
+ "con-bounces",
+ "contentions",
+ "waittime-min",
+ "waittime-max",
+ "waittime-total",
+ "acq-bounces",
+ "acquisitions",
+ "holdtime-min",
+ "holdtime-max",
+ "holdtime-total");
+ seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
+ seq_printf(m, "\n");
+}
+
+static void *ls_start(struct seq_file *m, loff_t *pos)
+{
+ struct lock_stat_seq *data = m->private;
+
+ if (*pos == 0)
+ return SEQ_START_TOKEN;
+
+ data->iter = data->stats + *pos;
+ if (data->iter >= data->iter_end)
+ data->iter = NULL;
+
+ return data->iter;
+}
+
+static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
+{
+ struct lock_stat_seq *data = m->private;
+
+ (*pos)++;
+
+ if (v == SEQ_START_TOKEN)
+ data->iter = data->stats;
+ else {
+ data->iter = v;
+ data->iter++;
+ }
+
+ if (data->iter == data->iter_end)
+ data->iter = NULL;
+
+ return data->iter;
+}
+
+static void ls_stop(struct seq_file *m, void *v)
+{
+}
+
+static int ls_show(struct seq_file *m, void *v)
+{
+ if (v == SEQ_START_TOKEN)
+ seq_header(m);
+ else
+ seq_stats(m, v);
+
+ return 0;
+}
+
+static struct seq_operations lockstat_ops = {
+ .start = ls_start,
+ .next = ls_next,
+ .stop = ls_stop,
+ .show = ls_show,
+};
+
+static int lock_stat_open(struct inode *inode, struct file *file)
+{
+ int res;
+ struct lock_class *class;
+ struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
+
+ if (!data)
+ return -ENOMEM;
+
+ res = seq_open(file, &lockstat_ops);
+ if (!res) {
+ struct lock_stat_data *iter = data->stats;
+ struct seq_file *m = file->private_data;
+
+ data->iter = iter;
+ list_for_each_entry(class, &all_lock_classes, lock_entry) {
+ iter->class = class;
+ iter->stats = lock_stats(class);
+ iter++;
+ }
+ data->iter_end = iter;
+
+ sort(data->stats, data->iter_end - data->iter,
+ sizeof(struct lock_stat_data),
+ lock_stat_cmp, NULL);
+
+ m->private = data;
+ } else
+ vfree(data);
+
+ return res;
+}
+
+static ssize_t lock_stat_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct lock_class *class;
+ char c;
+
+ if (count) {
+ if (get_user(c, buf))
+ return -EFAULT;
+
+ if (c != '0')
+ return count;
+
+ list_for_each_entry(class, &all_lock_classes, lock_entry)
+ clear_lock_stats(class);
+ }
+ return count;
+}
+
+static int lock_stat_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+
+ vfree(seq->private);
+ seq->private = NULL;
+ return seq_release(inode, file);
+}
+
+static const struct file_operations proc_lock_stat_operations = {
+ .open = lock_stat_open,
+ .write = lock_stat_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = lock_stat_release,
+};
+#endif /* CONFIG_LOCK_STAT */
+
+static int __init lockdep_proc_init(void)
+{
+ struct proc_dir_entry *entry;
+
+ entry = create_proc_entry("lockdep", S_IRUSR, NULL);
+ if (entry)
+ entry->proc_fops = &proc_lockdep_operations;
+
+ entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
+ if (entry)
+ entry->proc_fops = &proc_lockdep_stats_operations;
+
+#ifdef CONFIG_LOCK_STAT
+ entry = create_proc_entry("lock_stat", S_IRUSR, NULL);
+ if (entry)
+ entry->proc_fops = &proc_lock_stat_operations;
+#endif
+
+ return 0;
+}
+
+__initcall(lockdep_proc_init);
+
Index: linux-2.6-lttng.stable/kernel/lockdep_internals.h
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/lockdep_internals.h 2007-10-29 09:51:06.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,78 +0,0 @@
-/*
- * kernel/lockdep_internals.h
- *
- * Runtime locking correctness validator
- *
- * lockdep subsystem internal functions and variables.
- */
-
-/*
- * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
- * we track.
- *
- * We use the per-lock dependency maps in two ways: we grow it by adding
- * every to-be-taken lock to all currently held lock's own dependency
- * table (if it's not there yet), and we check it for lock order
- * conflicts and deadlocks.
- */
-#define MAX_LOCKDEP_ENTRIES 8192UL
-
-#define MAX_LOCKDEP_KEYS_BITS 11
-#define MAX_LOCKDEP_KEYS (1UL << MAX_LOCKDEP_KEYS_BITS)
-
-#define MAX_LOCKDEP_CHAINS_BITS 14
-#define MAX_LOCKDEP_CHAINS (1UL << MAX_LOCKDEP_CHAINS_BITS)
-
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the hash_lock.
- */
-#define MAX_STACK_TRACE_ENTRIES 262144UL
-
-extern struct list_head all_lock_classes;
-
-extern void
-get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
-
-extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
-
-extern unsigned long nr_lock_classes;
-extern unsigned long nr_list_entries;
-extern unsigned long nr_lock_chains;
-extern unsigned long nr_stack_trace_entries;
-
-extern unsigned int nr_hardirq_chains;
-extern unsigned int nr_softirq_chains;
-extern unsigned int nr_process_chains;
-extern unsigned int max_lockdep_depth;
-extern unsigned int max_recursion_depth;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-/*
- * Various lockdep statistics:
- */
-extern atomic_t chain_lookup_hits;
-extern atomic_t chain_lookup_misses;
-extern atomic_t hardirqs_on_events;
-extern atomic_t hardirqs_off_events;
-extern atomic_t redundant_hardirqs_on;
-extern atomic_t redundant_hardirqs_off;
-extern atomic_t softirqs_on_events;
-extern atomic_t softirqs_off_events;
-extern atomic_t redundant_softirqs_on;
-extern atomic_t redundant_softirqs_off;
-extern atomic_t nr_unused_locks;
-extern atomic_t nr_cyclic_checks;
-extern atomic_t nr_cyclic_check_recursions;
-extern atomic_t nr_find_usage_forwards_checks;
-extern atomic_t nr_find_usage_forwards_recursions;
-extern atomic_t nr_find_usage_backwards_checks;
-extern atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr) atomic_inc(ptr)
-# define debug_atomic_dec(ptr) atomic_dec(ptr)
-# define debug_atomic_read(ptr) atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr) do { } while (0)
-# define debug_atomic_dec(ptr) do { } while (0)
-# define debug_atomic_read(ptr) 0
-#endif
Index: linux-2.6-lttng.stable/kernel/lockdep_proc.c
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/lockdep_proc.c 2007-10-29 09:51:06.000000000 -0400
+++ /dev/null 1970-01-01 00:00:00.000000000 +0000
@@ -1,683 +0,0 @@
-/*
- * kernel/lockdep_proc.c
- *
- * Runtime locking correctness validator
- *
- * Started by Ingo Molnar:
- *
- * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <[email protected]>
- * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <[email protected]>
- *
- * Code for /proc/lockdep and /proc/lockdep_stats:
- *
- */
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/kallsyms.h>
-#include <linux/debug_locks.h>
-#include <linux/vmalloc.h>
-#include <linux/sort.h>
-#include <asm/uaccess.h>
-#include <asm/div64.h>
-
-#include "lockdep_internals.h"
-
-static void *l_next(struct seq_file *m, void *v, loff_t *pos)
-{
- struct lock_class *class;
-
- (*pos)++;
-
- if (v == SEQ_START_TOKEN)
- class = m->private;
- else {
- class = v;
-
- if (class->lock_entry.next != &all_lock_classes)
- class = list_entry(class->lock_entry.next,
- struct lock_class, lock_entry);
- else
- class = NULL;
- }
-
- return class;
-}
-
-static void *l_start(struct seq_file *m, loff_t *pos)
-{
- struct lock_class *class;
- loff_t i = 0;
-
- if (*pos == 0)
- return SEQ_START_TOKEN;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
- if (++i == *pos)
- return class;
- }
- return NULL;
-}
-
-static void l_stop(struct seq_file *m, void *v)
-{
-}
-
-static unsigned long count_forward_deps(struct lock_class *class)
-{
- struct lock_list *entry;
- unsigned long ret = 1;
-
- /*
- * Recurse this class's dependency list:
- */
- list_for_each_entry(entry, &class->locks_after, entry)
- ret += count_forward_deps(entry->class);
-
- return ret;
-}
-
-static unsigned long count_backward_deps(struct lock_class *class)
-{
- struct lock_list *entry;
- unsigned long ret = 1;
-
- /*
- * Recurse this class's dependency list:
- */
- list_for_each_entry(entry, &class->locks_before, entry)
- ret += count_backward_deps(entry->class);
-
- return ret;
-}
-
-static void print_name(struct seq_file *m, struct lock_class *class)
-{
- char str[128];
- const char *name = class->name;
-
- if (!name) {
- name = __get_key_name(class->key, str);
- seq_printf(m, "%s", name);
- } else{
- seq_printf(m, "%s", name);
- if (class->name_version > 1)
- seq_printf(m, "#%d", class->name_version);
- if (class->subclass)
- seq_printf(m, "/%d", class->subclass);
- }
-}
-
-static int l_show(struct seq_file *m, void *v)
-{
- unsigned long nr_forward_deps, nr_backward_deps;
- struct lock_class *class = v;
- struct lock_list *entry;
- char c1, c2, c3, c4;
-
- if (v == SEQ_START_TOKEN) {
- seq_printf(m, "all lock classes:\n");
- return 0;
- }
-
- seq_printf(m, "%p", class->key);
-#ifdef CONFIG_DEBUG_LOCKDEP
- seq_printf(m, " OPS:%8ld", class->ops);
-#endif
- nr_forward_deps = count_forward_deps(class);
- seq_printf(m, " FD:%5ld", nr_forward_deps);
-
- nr_backward_deps = count_backward_deps(class);
- seq_printf(m, " BD:%5ld", nr_backward_deps);
-
- get_usage_chars(class, &c1, &c2, &c3, &c4);
- seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
-
- seq_printf(m, ": ");
- print_name(m, class);
- seq_puts(m, "\n");
-
- list_for_each_entry(entry, &class->locks_after, entry) {
- if (entry->distance == 1) {
- seq_printf(m, " -> [%p] ", entry->class);
- print_name(m, entry->class);
- seq_puts(m, "\n");
- }
- }
- seq_puts(m, "\n");
-
- return 0;
-}
-
-static const struct seq_operations lockdep_ops = {
- .start = l_start,
- .next = l_next,
- .stop = l_stop,
- .show = l_show,
-};
-
-static int lockdep_open(struct inode *inode, struct file *file)
-{
- int res = seq_open(file, &lockdep_ops);
- if (!res) {
- struct seq_file *m = file->private_data;
-
- if (!list_empty(&all_lock_classes))
- m->private = list_entry(all_lock_classes.next,
- struct lock_class, lock_entry);
- else
- m->private = NULL;
- }
- return res;
-}
-
-static const struct file_operations proc_lockdep_operations = {
- .open = lockdep_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = seq_release,
-};
-
-static void lockdep_stats_debug_show(struct seq_file *m)
-{
-#ifdef CONFIG_DEBUG_LOCKDEP
- unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
- hi2 = debug_atomic_read(&hardirqs_off_events),
- hr1 = debug_atomic_read(&redundant_hardirqs_on),
- hr2 = debug_atomic_read(&redundant_hardirqs_off),
- si1 = debug_atomic_read(&softirqs_on_events),
- si2 = debug_atomic_read(&softirqs_off_events),
- sr1 = debug_atomic_read(&redundant_softirqs_on),
- sr2 = debug_atomic_read(&redundant_softirqs_off);
-
- seq_printf(m, " chain lookup misses: %11u\n",
- debug_atomic_read(&chain_lookup_misses));
- seq_printf(m, " chain lookup hits: %11u\n",
- debug_atomic_read(&chain_lookup_hits));
- seq_printf(m, " cyclic checks: %11u\n",
- debug_atomic_read(&nr_cyclic_checks));
- seq_printf(m, " cyclic-check recursions: %11u\n",
- debug_atomic_read(&nr_cyclic_check_recursions));
- seq_printf(m, " find-mask forwards checks: %11u\n",
- debug_atomic_read(&nr_find_usage_forwards_checks));
- seq_printf(m, " find-mask forwards recursions: %11u\n",
- debug_atomic_read(&nr_find_usage_forwards_recursions));
- seq_printf(m, " find-mask backwards checks: %11u\n",
- debug_atomic_read(&nr_find_usage_backwards_checks));
- seq_printf(m, " find-mask backwards recursions:%11u\n",
- debug_atomic_read(&nr_find_usage_backwards_recursions));
-
- seq_printf(m, " hardirq on events: %11u\n", hi1);
- seq_printf(m, " hardirq off events: %11u\n", hi2);
- seq_printf(m, " redundant hardirq ons: %11u\n", hr1);
- seq_printf(m, " redundant hardirq offs: %11u\n", hr2);
- seq_printf(m, " softirq on events: %11u\n", si1);
- seq_printf(m, " softirq off events: %11u\n", si2);
- seq_printf(m, " redundant softirq ons: %11u\n", sr1);
- seq_printf(m, " redundant softirq offs: %11u\n", sr2);
-#endif
-}
-
-static int lockdep_stats_show(struct seq_file *m, void *v)
-{
- struct lock_class *class;
- unsigned long nr_unused = 0, nr_uncategorized = 0,
- nr_irq_safe = 0, nr_irq_unsafe = 0,
- nr_softirq_safe = 0, nr_softirq_unsafe = 0,
- nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
- nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
- nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
- nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
- sum_forward_deps = 0, factor = 0;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
-
- if (class->usage_mask == 0)
- nr_unused++;
- if (class->usage_mask == LOCKF_USED)
- nr_uncategorized++;
- if (class->usage_mask & LOCKF_USED_IN_IRQ)
- nr_irq_safe++;
- if (class->usage_mask & LOCKF_ENABLED_IRQS)
- nr_irq_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
- nr_softirq_safe++;
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
- nr_softirq_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
- nr_hardirq_safe++;
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
- nr_hardirq_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
- nr_irq_read_safe++;
- if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
- nr_irq_read_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
- nr_softirq_read_safe++;
- if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
- nr_softirq_read_unsafe++;
- if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
- nr_hardirq_read_safe++;
- if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
- nr_hardirq_read_unsafe++;
-
- sum_forward_deps += count_forward_deps(class);
- }
-#ifdef CONFIG_DEBUG_LOCKDEP
- DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
-#endif
- seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
- nr_lock_classes, MAX_LOCKDEP_KEYS);
- seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
- nr_list_entries, MAX_LOCKDEP_ENTRIES);
- seq_printf(m, " indirect dependencies: %11lu\n",
- sum_forward_deps);
-
- /*
- * Total number of dependencies:
- *
- * All irq-safe locks may nest inside irq-unsafe locks,
- * plus all the other known dependencies:
- */
- seq_printf(m, " all direct dependencies: %11lu\n",
- nr_irq_unsafe * nr_irq_safe +
- nr_hardirq_unsafe * nr_hardirq_safe +
- nr_list_entries);
-
- /*
- * Estimated factor between direct and indirect
- * dependencies:
- */
- if (nr_list_entries)
- factor = sum_forward_deps / nr_list_entries;
-
-#ifdef CONFIG_PROVE_LOCKING
- seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
- nr_lock_chains, MAX_LOCKDEP_CHAINS);
-#endif
-
-#ifdef CONFIG_TRACE_IRQFLAGS
- seq_printf(m, " in-hardirq chains: %11u\n",
- nr_hardirq_chains);
- seq_printf(m, " in-softirq chains: %11u\n",
- nr_softirq_chains);
-#endif
- seq_printf(m, " in-process chains: %11u\n",
- nr_process_chains);
- seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
- nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
- seq_printf(m, " combined max dependencies: %11u\n",
- (nr_hardirq_chains + 1) *
- (nr_softirq_chains + 1) *
- (nr_process_chains + 1)
- );
- seq_printf(m, " hardirq-safe locks: %11lu\n",
- nr_hardirq_safe);
- seq_printf(m, " hardirq-unsafe locks: %11lu\n",
- nr_hardirq_unsafe);
- seq_printf(m, " softirq-safe locks: %11lu\n",
- nr_softirq_safe);
- seq_printf(m, " softirq-unsafe locks: %11lu\n",
- nr_softirq_unsafe);
- seq_printf(m, " irq-safe locks: %11lu\n",
- nr_irq_safe);
- seq_printf(m, " irq-unsafe locks: %11lu\n",
- nr_irq_unsafe);
-
- seq_printf(m, " hardirq-read-safe locks: %11lu\n",
- nr_hardirq_read_safe);
- seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
- nr_hardirq_read_unsafe);
- seq_printf(m, " softirq-read-safe locks: %11lu\n",
- nr_softirq_read_safe);
- seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
- nr_softirq_read_unsafe);
- seq_printf(m, " irq-read-safe locks: %11lu\n",
- nr_irq_read_safe);
- seq_printf(m, " irq-read-unsafe locks: %11lu\n",
- nr_irq_read_unsafe);
-
- seq_printf(m, " uncategorized locks: %11lu\n",
- nr_uncategorized);
- seq_printf(m, " unused locks: %11lu\n",
- nr_unused);
- seq_printf(m, " max locking depth: %11u\n",
- max_lockdep_depth);
- seq_printf(m, " max recursion depth: %11u\n",
- max_recursion_depth);
- lockdep_stats_debug_show(m);
- seq_printf(m, " debug_locks: %11u\n",
- debug_locks);
-
- return 0;
-}
-
-static int lockdep_stats_open(struct inode *inode, struct file *file)
-{
- return single_open(file, lockdep_stats_show, NULL);
-}
-
-static const struct file_operations proc_lockdep_stats_operations = {
- .open = lockdep_stats_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
-
-#ifdef CONFIG_LOCK_STAT
-
-struct lock_stat_data {
- struct lock_class *class;
- struct lock_class_stats stats;
-};
-
-struct lock_stat_seq {
- struct lock_stat_data *iter;
- struct lock_stat_data *iter_end;
- struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
-};
-
-/*
- * sort on absolute number of contentions
- */
-static int lock_stat_cmp(const void *l, const void *r)
-{
- const struct lock_stat_data *dl = l, *dr = r;
- unsigned long nl, nr;
-
- nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
- nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
-
- return nr - nl;
-}
-
-static void seq_line(struct seq_file *m, char c, int offset, int length)
-{
- int i;
-
- for (i = 0; i < offset; i++)
- seq_puts(m, " ");
- for (i = 0; i < length; i++)
- seq_printf(m, "%c", c);
- seq_puts(m, "\n");
-}
-
-static void snprint_time(char *buf, size_t bufsiz, s64 nr)
-{
- unsigned long rem;
-
- rem = do_div(nr, 1000); /* XXX: do_div_signed */
- snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
-}
-
-static void seq_time(struct seq_file *m, s64 time)
-{
- char num[15];
-
- snprint_time(num, sizeof(num), time);
- seq_printf(m, " %14s", num);
-}
-
-static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
-{
- seq_printf(m, "%14lu", lt->nr);
- seq_time(m, lt->min);
- seq_time(m, lt->max);
- seq_time(m, lt->total);
-}
-
-static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
-{
- char name[39];
- struct lock_class *class;
- struct lock_class_stats *stats;
- int i, namelen;
-
- class = data->class;
- stats = &data->stats;
-
- namelen = 38;
- if (class->name_version > 1)
- namelen -= 2; /* XXX truncates versions > 9 */
- if (class->subclass)
- namelen -= 2;
-
- if (!class->name) {
- char str[KSYM_NAME_LEN];
- const char *key_name;
-
- key_name = __get_key_name(class->key, str);
- snprintf(name, namelen, "%s", key_name);
- } else {
- snprintf(name, namelen, "%s", class->name);
- }
- namelen = strlen(name);
- if (class->name_version > 1) {
- snprintf(name+namelen, 3, "#%d", class->name_version);
- namelen += 2;
- }
- if (class->subclass) {
- snprintf(name+namelen, 3, "/%d", class->subclass);
- namelen += 2;
- }
-
- if (stats->write_holdtime.nr) {
- if (stats->read_holdtime.nr)
- seq_printf(m, "%38s-W:", name);
- else
- seq_printf(m, "%40s:", name);
-
- seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
- seq_lock_time(m, &stats->write_waittime);
- seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
- seq_lock_time(m, &stats->write_holdtime);
- seq_puts(m, "\n");
- }
-
- if (stats->read_holdtime.nr) {
- seq_printf(m, "%38s-R:", name);
- seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
- seq_lock_time(m, &stats->read_waittime);
- seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
- seq_lock_time(m, &stats->read_holdtime);
- seq_puts(m, "\n");
- }
-
- if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
- return;
-
- if (stats->read_holdtime.nr)
- namelen += 2;
-
- for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
- char sym[KSYM_SYMBOL_LEN];
- char ip[32];
-
- if (class->contention_point[i] == 0)
- break;
-
- if (!i)
- seq_line(m, '-', 40-namelen, namelen);
-
- sprint_symbol(sym, class->contention_point[i]);
- snprintf(ip, sizeof(ip), "[<%p>]",
- (void *)class->contention_point[i]);
- seq_printf(m, "%40s %14lu %29s %s\n", name,
- stats->contention_point[i],
- ip, sym);
- }
- if (i) {
- seq_puts(m, "\n");
- seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
- seq_puts(m, "\n");
- }
-}
-
-static void seq_header(struct seq_file *m)
-{
- seq_printf(m, "lock_stat version 0.2\n");
- seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
- seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
- "%14s %14s\n",
- "class name",
- "con-bounces",
- "contentions",
- "waittime-min",
- "waittime-max",
- "waittime-total",
- "acq-bounces",
- "acquisitions",
- "holdtime-min",
- "holdtime-max",
- "holdtime-total");
- seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
- seq_printf(m, "\n");
-}
-
-static void *ls_start(struct seq_file *m, loff_t *pos)
-{
- struct lock_stat_seq *data = m->private;
-
- if (*pos == 0)
- return SEQ_START_TOKEN;
-
- data->iter = data->stats + *pos;
- if (data->iter >= data->iter_end)
- data->iter = NULL;
-
- return data->iter;
-}
-
-static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
-{
- struct lock_stat_seq *data = m->private;
-
- (*pos)++;
-
- if (v == SEQ_START_TOKEN)
- data->iter = data->stats;
- else {
- data->iter = v;
- data->iter++;
- }
-
- if (data->iter == data->iter_end)
- data->iter = NULL;
-
- return data->iter;
-}
-
-static void ls_stop(struct seq_file *m, void *v)
-{
-}
-
-static int ls_show(struct seq_file *m, void *v)
-{
- if (v == SEQ_START_TOKEN)
- seq_header(m);
- else
- seq_stats(m, v);
-
- return 0;
-}
-
-static struct seq_operations lockstat_ops = {
- .start = ls_start,
- .next = ls_next,
- .stop = ls_stop,
- .show = ls_show,
-};
-
-static int lock_stat_open(struct inode *inode, struct file *file)
-{
- int res;
- struct lock_class *class;
- struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
-
- if (!data)
- return -ENOMEM;
-
- res = seq_open(file, &lockstat_ops);
- if (!res) {
- struct lock_stat_data *iter = data->stats;
- struct seq_file *m = file->private_data;
-
- data->iter = iter;
- list_for_each_entry(class, &all_lock_classes, lock_entry) {
- iter->class = class;
- iter->stats = lock_stats(class);
- iter++;
- }
- data->iter_end = iter;
-
- sort(data->stats, data->iter_end - data->iter,
- sizeof(struct lock_stat_data),
- lock_stat_cmp, NULL);
-
- m->private = data;
- } else
- vfree(data);
-
- return res;
-}
-
-static ssize_t lock_stat_write(struct file *file, const char __user *buf,
- size_t count, loff_t *ppos)
-{
- struct lock_class *class;
- char c;
-
- if (count) {
- if (get_user(c, buf))
- return -EFAULT;
-
- if (c != '0')
- return count;
-
- list_for_each_entry(class, &all_lock_classes, lock_entry)
- clear_lock_stats(class);
- }
- return count;
-}
-
-static int lock_stat_release(struct inode *inode, struct file *file)
-{
- struct seq_file *seq = file->private_data;
-
- vfree(seq->private);
- seq->private = NULL;
- return seq_release(inode, file);
-}
-
-static const struct file_operations proc_lock_stat_operations = {
- .open = lock_stat_open,
- .write = lock_stat_write,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = lock_stat_release,
-};
-#endif /* CONFIG_LOCK_STAT */
-
-static int __init lockdep_proc_init(void)
-{
- struct proc_dir_entry *entry;
-
- entry = create_proc_entry("lockdep", S_IRUSR, NULL);
- if (entry)
- entry->proc_fops = &proc_lockdep_operations;
-
- entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
- if (entry)
- entry->proc_fops = &proc_lockdep_stats_operations;
-
-#ifdef CONFIG_LOCK_STAT
- entry = create_proc_entry("lock_stat", S_IRUSR, NULL);
- if (entry)
- entry->proc_fops = &proc_lock_stat_operations;
-#endif
-
- return 0;
-}
-
-__initcall(lockdep_proc_init);
-
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
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