On Thu, 28 Jun 2007, Kyle McMartin wrote:
woah woah woah. This could push critical bits of the register dump or
stacktrace off the screen... Barring any other problems with the patch,
this should probably be dumped in the oops header, not trailing it where
it could hide critical debugging info.
Okay, fair enough. Fixed version follows. I also fixed some checkpatch
issues that I missed before.
However, please note that in general, the info dumped by this will consist
of only a few lines. In our implementations, I believe that we only dump one
line per notifier.
joshua
--
From: Joshua Wise <[email protected]>
Version: 2
Background:
When managing a large number of servers, as Google does, it's sometimes
useful to get an "at-a-glance" view of a machine when it crashes. When no
other post-mortem is possible, it's often useful to know how long the
machine has been powered on, which kernel it was running, and possibly
other information that a driver may have logged. Up until now, there was no
real way to do this other than to keep statistics outside to the machine.
Description:
This patch adds a call chain to be invoked when the system oopses or
panics. Traps have been added to i386 and x86_64 kernels, but it should be
trivial to add support for more architectures. Two sample notifiers have
been added -- an uptime printer, and a utsname printer for showing various
statistics about the running system.
Remaining issues:
* Is do_posix_clock_monotonic_gettime really the right API?
* Should this be on by default, or a disablable Kconfig entry?
Testing:
I accidentally built my testing kernel without the IDE drivers. It panic()ed
immediately, and informed me that my uptime was 0.38 seconds.
Credits:
This code was mainly written by Mike Waychison <[email protected]> and
Masoud Sharbiani <[email protected]>.
Changelog:
v2 -- fixed some checkpatch issues. Moved dumping to before Oopses, as per
the suggestion of Kyle McMartin <[email protected]>.
Patch:
This patch is against git 48d8d7ee5dd17c64833e0343ab4ae8ef01cc2648.
Signed-off-by: Joshua Wise <[email protected]>
Acked-by: Mike Waychison <[email protected]>
--
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index 06dfa65..f969c04 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -301,6 +301,8 @@ void show_regs(struct pt_regs * regs)
{
unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
+ atomic_notifier_call_chain(&info_dumper_list, 0, NULL);
+
printk("\n");
printk("Pid: %d, comm: %20s\n", current->pid, current->comm);
printk("EIP: %04x:[<%08lx>] CPU: %d\n",0xffff & regs->xcs,regs->eip, smp_processor_id());
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index 90da057..2ad7f8c 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -289,6 +289,9 @@ void show_registers(struct pt_regs *regs
ss = regs->xss & 0xffff;
}
print_modules();
+
+ atomic_notifier_call_chain(&info_dumper_list, 0, NULL);
+
printk(KERN_EMERG "CPU: %d\n"
KERN_EMERG "EIP: %04x:[<%08lx>] %s VLI\n"
KERN_EMERG "EFLAGS: %08lx (%s %.*s)\n",
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 5909039..e7f0298 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -353,6 +353,7 @@ void __show_regs(struct pt_regs * regs)
void show_regs(struct pt_regs *regs)
{
+ atomic_notifier_call_chain(&info_dumper_list, 0, NULL);
printk("CPU %d:", smp_processor_id());
__show_regs(regs);
show_trace(NULL, regs, (void *)(regs + 1));
diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c
index aac1c0b..3d228d0 100644
--- a/arch/x86_64/kernel/traps.c
+++ b/arch/x86_64/kernel/traps.c
@@ -410,6 +410,8 @@ void show_registers(struct pt_regs *regs
const int cpu = smp_processor_id();
struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+ atomic_notifier_call_chain(&info_dumper_list, 0, NULL);
+
rsp = regs->rsp;
printk("CPU %d ", cpu);
__show_regs(regs);
diff --git a/include/asm-blackfin/macros.h b/include/asm-blackfin/macros.h
deleted file mode 100644
index e69de29..0000000
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 7a48525..2058e58 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -104,6 +104,7 @@ #define abs(x) ({ \
})
extern struct atomic_notifier_head panic_notifier_list;
+extern struct atomic_notifier_head info_dumper_list;
extern long (*panic_blink)(long time);
NORET_TYPE void panic(const char * fmt, ...)
__attribute__ ((NORET_AND format (printf, 1, 2)));
diff --git a/kernel/panic.c b/kernel/panic.c
index 623d182..8bae618 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -97,6 +97,7 @@ #ifdef CONFIG_SMP
#endif
atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
+ atomic_notifier_call_chain(&info_dumper_list, 0, NULL);
if (!panic_blink)
panic_blink = no_blink;
diff --git a/kernel/sys.c b/kernel/sys.c
index 872271c..21b9ca1 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -98,6 +98,39 @@ struct pid *cad_pid;
EXPORT_SYMBOL(cad_pid);
/*
+ * Notifier list for kernel code which wants to printk hardware specific
+ * information at Oops or panic time.
+ */
+
+ATOMIC_NOTIFIER_HEAD(info_dumper_list);
+EXPORT_SYMBOL(info_dumper_list);
+
+/*
+ * Dump out UTS info on oops / panic.
+ */
+
+static int dump_utsname(struct notifier_block *self, unsigned long v, void *p)
+{
+ printk (KERN_EMERG "%s %s %s %s %s %s\n",
+ utsname()->sysname,
+ utsname()->nodename,
+ utsname()->release,
+ utsname()->version,
+ utsname()->machine,
+ utsname()->domainname);
+ return 0;
+}
+
+static struct notifier_block utsname_notifier;
+
+static int __init register_utsname_dump(void) {
+ utsname_notifier.notifier_call = dump_utsname;
+ atomic_notifier_chain_register(&info_dumper_list, &utsname_notifier);
+ return 0;
+}
+__initcall(register_utsname_dump);
+
+/*
* Notifier list for kernel code which wants to be called
* at shutdown. This is used to stop any idling DMA operations
* and the like.
diff --git a/kernel/time.c b/kernel/time.c
index f04791f..9c81504 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -31,6 +31,7 @@ #include <linux/module.h>
#include <linux/timex.h>
#include <linux/capability.h>
#include <linux/errno.h>
+#include <linux/notifier.h>
#include <linux/syscalls.h>
#include <linux/security.h>
#include <linux/fs.h>
@@ -744,3 +745,34 @@ EXPORT_SYMBOL(get_jiffies_64);
#endif
EXPORT_SYMBOL(jiffies);
+
+/*
+ * Dump out uptime info on oops / panic.
+ *
+ * FIXME: Should I be just using get_jiffies64()? what if the lock there
+ * is damaged beyond any recognition?
+ */
+
+static int dump_uptime(struct notifier_block *self, unsigned long v, void *p)
+{
+ struct timespec uptime;
+ /* The logic below is very much like how kernel
+ * prepares /proc/uptime.
+ */
+ do_posix_clock_monotonic_gettime(&uptime);
+ printk(KERN_EMERG "Uptime (seconds): %lu.%02lu\n",
+ (unsigned long) uptime.tv_sec,
+ (uptime.tv_nsec / (NSEC_PER_SEC / 100)));
+
+ return 0;
+}
+
+static struct notifier_block uptime_notifier;
+
+static int __init register_uptime_dump(void) {
+ uptime_notifier.notifier_call = dump_uptime;
+ atomic_notifier_chain_register(&info_dumper_list, &uptime_notifier);
+ return 0;
+}
+__initcall(register_uptime_dump);
+
-
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