Some x86 server fires NMI with reason 0x80 up if a parity error
occurs on its PCI-bus system or DIMM module.
However, such NMI cannot stop the system and data pollution,
because the NMI is _not_ "unknown", through unknown_nmi_panic
can panic the system on NMI which has no reason bits.
This patch adds "mem_nmi_panic" sysctl parameter that enable
system to switch its action on such NMI originated in a hard error.
Also it seems that x86_86 has same situation and problem,
so this is a couple of patch for 2 archs, i386 and x86_64.
signed-off-by: Hidetoshi Seto <[email protected]>
H.Seto
-----
Documentation/filesystems/proc.txt | 16 +++++++
arch/i386/kernel/nmi.c | 71 +++++++++++++++++++++++++++-------
arch/x86_64/kernel/nmi.c | 76 ++++++++++++++++++++++++++++---------
arch/x86_64/kernel/traps.c | 2
include/asm-x86_64/nmi.h | 1
include/linux/sysctl.h | 1
kernel/sysctl.c | 13 ++++++
7 files changed, 146 insertions(+), 34 deletions(-)
Index: linux-2.6.15-rc5/kernel/sysctl.c
===================================================================
--- linux-2.6.15-rc5.orig/kernel/sysctl.c
+++ linux-2.6.15-rc5/kernel/sysctl.c
@@ -72,6 +72,9 @@ extern int pid_max_min, pid_max_max;
int unknown_nmi_panic;
extern int proc_unknown_nmi_panic(ctl_table *, int, struct file *,
void __user *, size_t *, loff_t *);
+int mem_nmi_panic;
+extern int proc_mem_nmi_panic(ctl_table *, int, struct file *,
+ void __user *, size_t *, loff_t *);
#endif
/* this is needed for the proc_dointvec_minmax for [fs_]overflow UID and GID */
@@ -656,6 +659,16 @@ static ctl_table kern_table[] = {
.proc_handler = &proc_dointvec,
},
#endif
+#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
+ {
+ .ctl_name = KERN_MEM_NMI_PANIC,
+ .procname = "mem_nmi_panic",
+ .data = &mem_nmi_panic,
+ .maxlen = sizeof (int),
+ .mode = 0644,
+ .proc_handler = &proc_mem_nmi_panic,
+ },
+#endif
{ .ctl_name = 0 }
};
Index: linux-2.6.15-rc5/arch/i386/kernel/nmi.c
===================================================================
--- linux-2.6.15-rc5.orig/arch/i386/kernel/nmi.c
+++ linux-2.6.15-rc5/arch/i386/kernel/nmi.c
@@ -34,6 +34,7 @@
unsigned int nmi_watchdog = NMI_NONE;
extern int unknown_nmi_panic;
+extern int mem_nmi_panic;
static unsigned int nmi_hz = HZ;
static unsigned int nmi_perfctr_msr; /* the MSR to reset in NMI handler */
static unsigned int nmi_p4_cccr_val;
@@ -572,15 +573,40 @@ void nmi_watchdog_tick (struct pt_regs *
#ifdef CONFIG_SYSCTL
-static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
+static int nmi_panic_callback(struct pt_regs *regs, int cpu)
{
unsigned char reason = get_nmi_reason();
char buf[64];
- if (!(reason & 0xc0)) {
+ if (unknown_nmi_panic && !(reason & 0xc0)) {
sprintf(buf, "NMI received for unknown reason %02x\n", reason);
die_nmi(regs, buf);
}
+ if (mem_nmi_panic && (reason & 0x80)) {
+ sprintf(buf, "NMI received for possible memory parity error "
+ "%02x\n", reason);
+ die_nmi(regs, buf);
+ }
+ return 0;
+}
+
+static DEFINE_SPINLOCK(nmi_panic_callback_lock);
+static int nmi_panic_callback_active = 0;
+
+static int switch_nmi_panic_callback(void)
+{
+ if (unknown_nmi_panic || mem_nmi_panic) {
+ if (nmi_panic_callback_active)
+ return 0;
+ if (reserve_lapic_nmi() < 0)
+ return -EBUSY;
+ set_nmi_callback(nmi_panic_callback);
+ nmi_panic_callback_active = 1;
+ } else {
+ release_lapic_nmi();
+ unset_nmi_callback();
+ nmi_panic_callback_active = 0;
+ }
return 0;
}
@@ -590,25 +616,40 @@ static int unknown_nmi_panic_callback(st
int proc_unknown_nmi_panic(ctl_table *table, int write, struct file *file,
void __user *buffer, size_t *length, loff_t *ppos)
{
- int old_state;
+ int old_state, ret = 0;
+ spin_lock(&nmi_panic_callback_lock);
old_state = unknown_nmi_panic;
proc_dointvec(table, write, file, buffer, length, ppos);
- if (!!old_state == !!unknown_nmi_panic)
- return 0;
- if (unknown_nmi_panic) {
- if (reserve_lapic_nmi() < 0) {
+ if (!!old_state != !!unknown_nmi_panic) {
+ ret = switch_nmi_panic_callback();
+ if (ret)
unknown_nmi_panic = 0;
- return -EBUSY;
- } else {
- set_nmi_callback(unknown_nmi_panic_callback);
- }
- } else {
- release_lapic_nmi();
- unset_nmi_callback();
}
- return 0;
+ spin_unlock(&nmi_panic_callback_lock);
+ return ret;
+}
+
+/*
+ * proc handler for /proc/sys/kernel/mem_nmi_panic
+ */
+int proc_mem_nmi_panic(ctl_table *table, int write, struct file *file,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ int old_state, ret = 0;
+
+ spin_lock(&nmi_panic_callback_lock);
+ old_state = mem_nmi_panic;
+ proc_dointvec(table, write, file, buffer, length, ppos);
+
+ if (!!old_state != !!mem_nmi_panic) {
+ ret = switch_nmi_panic_callback();
+ if (ret)
+ mem_nmi_panic = 0;
+ }
+ spin_unlock(&nmi_panic_callback_lock);
+ return ret;
}
#endif
Index: linux-2.6.15-rc5/Documentation/filesystems/proc.txt
===================================================================
--- linux-2.6.15-rc5.orig/Documentation/filesystems/proc.txt
+++ linux-2.6.15-rc5/Documentation/filesystems/proc.txt
@@ -1130,6 +1130,22 @@ If a system hangs up, try pressing the N
And NMI watchdog will be disabled when the value in this file is set to
non-zero.
+mem_nmi_panic
+-----------------
+
+The value in this file affects behavior of handling NMI. When the value is
+non-zero, NMI with reason 0x80 is trapped and then panic occurs. At that time,
+kernel debugging information is displayed on console.
+
+Some x86 server fires NMI with reason 0x80 up if a parity error occurs on
+its PCI-bus system or DIMM module, for example.
+
+[NOTE]
+ This function and oprofile share a NMI callback. Therefore this function
+ cannot be enabled when oprofile is activated.
+ And NMI watchdog will be disabled when the value in this file is set to
+ non-zero.
+
2.4 /proc/sys/vm - The virtual memory subsystem
-----------------------------------------------
Index: linux-2.6.15-rc5/arch/x86_64/kernel/nmi.c
===================================================================
--- linux-2.6.15-rc5.orig/arch/x86_64/kernel/nmi.c
+++ linux-2.6.15-rc5/arch/x86_64/kernel/nmi.c
@@ -488,7 +488,7 @@ void nmi_watchdog_tick (struct pt_regs *
local_set(&__get_cpu_var(alert_counter), 0);
return;
}
- die_nmi("NMI Watchdog detected LOCKUP on CPU %d\n", regs);
+ die_nmi("NMI Watchdog detected LOCKUP", regs);
}
} else {
__get_cpu_var(last_irq_sum) = sum;
@@ -540,14 +540,39 @@ void unset_nmi_callback(void)
#ifdef CONFIG_SYSCTL
-static int unknown_nmi_panic_callback(struct pt_regs *regs, int cpu)
+static int nmi_panic_callback(struct pt_regs *regs, int cpu)
{
unsigned char reason = get_nmi_reason();
char buf[64];
- if (!(reason & 0xc0)) {
- sprintf(buf, "NMI received for unknown reason %02x\n", reason);
- die_nmi(buf,regs);
+ if (unknown_nmi_panic && !(reason & 0xc0)) {
+ sprintf(buf, "NMI received for unknown reason %02x", reason);
+ die_nmi(buf, regs);
+ }
+ if (mem_nmi_panic && (reason & 0x80)) {
+ sprintf(buf, "NMI received for possible memory parity error "
+ "%02x", reason);
+ die_nmi(buf, regs);
+ }
+ return 0;
+}
+
+static DEFINE_SPINLOCK(nmi_panic_callback_lock);
+static int nmi_panic_callback_active = 0;
+
+static int switch_nmi_panic_callback(void)
+{
+ if (unknown_nmi_panic || mem_nmi_panic) {
+ if (nmi_panic_callback_active)
+ return 0;
+ if (reserve_lapic_nmi() < 0)
+ return -EBUSY;
+ set_nmi_callback(nmi_panic_callback);
+ nmi_panic_callback_active = 1;
+ } else {
+ release_lapic_nmi();
+ unset_nmi_callback();
+ nmi_panic_callback_active = 0;
}
return 0;
}
@@ -558,25 +583,40 @@ static int unknown_nmi_panic_callback(st
int proc_unknown_nmi_panic(struct ctl_table *table, int write, struct file *file,
void __user *buffer, size_t *length, loff_t *ppos)
{
- int old_state;
+ int old_state, ret = 0;
+ spin_lock(&nmi_panic_callback_lock);
old_state = unknown_nmi_panic;
proc_dointvec(table, write, file, buffer, length, ppos);
- if (!!old_state == !!unknown_nmi_panic)
- return 0;
- if (unknown_nmi_panic) {
- if (reserve_lapic_nmi() < 0) {
+ if (!!old_state != !!unknown_nmi_panic) {
+ ret = switch_nmi_panic_callback();
+ if (ret)
unknown_nmi_panic = 0;
- return -EBUSY;
- } else {
- set_nmi_callback(unknown_nmi_panic_callback);
- }
- } else {
- release_lapic_nmi();
- unset_nmi_callback();
}
- return 0;
+ spin_unlock(&nmi_panic_callback_lock);
+ return ret;
+}
+
+/*
+ * proc handler for /proc/sys/kernel/mem_nmi_panic
+ */
+int proc_mem_nmi_panic(struct ctl_table *table, int write, struct file *file,
+ void __user *buffer, size_t *length, loff_t *ppos)
+{
+ int old_state, ret;
+
+ spin_lock(&nmi_panic_callback_lock);
+ old_state = mem_nmi_panic;
+ proc_dointvec(table, write, file, buffer, length, ppos);
+
+ if (!!old_state != !!mem_nmi_panic)
+ ret = switch_nmi_panic_callback();
+ if (ret)
+ mem_nmi_panic = 0;
+ }
+ spin_unlock(&nmi_panic_callback_lock);
+ return ret;
}
#endif
Index: linux-2.6.15-rc5/include/asm-x86_64/nmi.h
===================================================================
--- linux-2.6.15-rc5.orig/include/asm-x86_64/nmi.h
+++ linux-2.6.15-rc5/include/asm-x86_64/nmi.h
@@ -53,6 +53,7 @@ extern void die_nmi(char *str, struct pt
extern int panic_on_timeout;
extern int unknown_nmi_panic;
+extern int mem_nmi_panic;
extern int check_nmi_watchdog(void);
Index: linux-2.6.15-rc5/arch/x86_64/kernel/traps.c
===================================================================
--- linux-2.6.15-rc5.orig/arch/x86_64/kernel/traps.c
+++ linux-2.6.15-rc5/arch/x86_64/kernel/traps.c
@@ -413,7 +413,7 @@ void die_nmi(char *str, struct pt_regs *
* We are in trouble anyway, lets at least try
* to get a message out.
*/
- printk(str, safe_smp_processor_id());
+ printk("%s on CPU %d\n", str, safe_smp_processor_id());
show_registers(regs);
if (panic_on_timeout || panic_on_oops)
panic("nmi watchdog");
Index: linux-2.6.15-rc5/include/linux/sysctl.h
===================================================================
--- linux-2.6.15-rc5.orig/include/linux/sysctl.h
+++ linux-2.6.15-rc5/include/linux/sysctl.h
@@ -146,6 +146,7 @@ enum
KERN_RANDOMIZE=68, /* int: randomize virtual address space */
KERN_SETUID_DUMPABLE=69, /* int: behaviour of dumps for setuid core */
KERN_SPIN_RETRY=70, /* int: number of spinlock retries */
+ KERN_MEM_NMI_PANIC=71, /* int: memory nmi panic flag */
};
-
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