Messages in this thread Patch in this message | | | Date | Thu, 28 Jun 2007 15:05:56 -0700 (PDT) | From | Joshua Wise <> | Subject | [PATCH] Info dump on Oops or panic() |
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From: Joshua Wise <jwise@google.com>
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 <mikew@google.com> and Masoud Sharbiani <masouds@google.com>.
Patch: This patch is against git 48d8d7ee5dd17c64833e0343ab4ae8ef01cc2648.
Signed-off-by: Joshua Wise <jwise@google.com> Acked-by: Mike Waychison <mikew@google.com>
--
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c index 06dfa65..42d4397 100644 --- a/arch/i386/kernel/process.c +++ b/arch/i386/kernel/process.c @@ -325,6 +325,8 @@ void show_regs(struct pt_regs * regs) cr4 = read_cr4_safe(); printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4); show_trace(NULL, regs, ®s->esp); + + atomic_notifier_call_chain(&info_dumper_list, 0, NULL); }
/* diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c index 90da057..16668c2 100644 --- a/arch/i386/kernel/traps.c +++ b/arch/i386/kernel/traps.c @@ -341,6 +341,8 @@ void show_registers(struct pt_regs *regs } } printk("\n"); + + atomic_notifier_call_chain(&info_dumper_list, 0, NULL); }
int is_valid_bugaddr(unsigned long eip) diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c index 5909039..7b0619a 100644 --- a/arch/x86_64/kernel/process.c +++ b/arch/x86_64/kernel/process.c @@ -356,6 +356,7 @@ void show_regs(struct pt_regs *regs) printk("CPU %d:", smp_processor_id()); __show_regs(regs); show_trace(NULL, regs, (void *)(regs + 1)); + atomic_notifier_call_chain(&info_dumper_list, 0, NULL); }
/* diff --git a/arch/x86_64/kernel/traps.c b/arch/x86_64/kernel/traps.c index aac1c0b..e443613 100644 --- a/arch/x86_64/kernel/traps.c +++ b/arch/x86_64/kernel/traps.c @@ -439,6 +439,8 @@ bad: } } printk("\n"); + + atomic_notifier_call_chain(&info_dumper_list, 0, NULL); }
int is_valid_bugaddr(unsigned long rip) 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..5bbe926 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 ("%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..d5ae5e0 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 +745,33 @@ 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("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); + - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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