Messages in this thread |  | | Date | Thu, 26 May 2011 19:38:19 +0200 | Subject | Re: [Patch 1/6] XPANIC: Add extended panic interface | From | richard -rw- weinberger <> |
| |
On Thu, May 26, 2011 at 7:12 PM, K.Prasad <prasad@linux.vnet.ibm.com> wrote: > > commit e668fa1aea7844ac4c7ea09030a2f3e647a4adb1 > Author: Andi Kleen <ak@linux.intel.com> > Date: Fri Nov 19 18:36:44 2010 +0100 > > XPANIC: Add extended panic interface > > One panic size doesn't fit all. > > Machine check has some special requirements on panic, like: > - It wants to do a reboot timeout by default so that the machine > check event can be logged to disk after warm reboot. > - For memory errors it usually doesn't want to do crash dumps because > that can lead to crash loops (dumping corrupted memory would > lead to another machine check) > - It doesn't want to do backtraces because machine checks > are not a kernel bug. > > In a earlier patch this was done with various adhoc hacks, > but it's cleaner to extend panic to a 'xpanic' that directly > gets a flag and timeout argument. > > The only user right now will be x86 machine checks, but I consider > it likely that other users will switch to this too. > > For example one obvious candidate would be the "no root > found" panic which doesn't really deserve a backtrace. > > I exported a vpanic() interface too as a global. That's not > needed by the current user, but the interface has to exist > internally anyways and I could see how other code would > find a v* variant of panic useful. > > Originally based on a suggestion by H. Peter Anvin. > Signed-off-by: Andi Kleen <ak@linux.intel.com> > > --- > include/linux/kernel.h | 11 +++++++++++ > kernel/panic.c | 41 +++++++++++++++++++++++++++++++---------- > 2 files changed, 42 insertions(+), 10 deletions(-) > > Index: linux-2.6.slim_kdump/include/linux/kernel.h > =================================================================== > --- linux-2.6.slim_kdump.orig/include/linux/kernel.h > +++ linux-2.6.slim_kdump/include/linux/kernel.h > @@ -175,10 +175,21 @@ static inline void might_fault(void) > } > #endif > > +enum panic_flags { > + PANIC_NO_KEXEC = (1 << 0), > + PANIC_NO_BACKTRACE = (1 << 1), > +}; > + > extern struct atomic_notifier_head panic_notifier_list; > extern long (*panic_blink)(int state); > NORET_TYPE void panic(const char * fmt, ...) > __attribute__ ((NORET_AND format (printf, 1, 2))) __cold; > +NORET_TYPE void xpanic(enum panic_flags flags, int timeout, > + const char *fmt, ...) > + __attribute__ ((NORET_AND format (printf, 3, 4))) __cold; > +NORET_TYPE void vpanic(enum panic_flags flags, int timeout, > + const char *fmt, > + va_list ap) __noreturn __cold; > extern void oops_enter(void); > extern void oops_exit(void); > void print_oops_end_marker(void); > Index: linux-2.6.slim_kdump/kernel/panic.c > =================================================================== > --- linux-2.6.slim_kdump.orig/kernel/panic.c > +++ linux-2.6.slim_kdump/kernel/panic.c > @@ -57,14 +57,37 @@ EXPORT_SYMBOL(panic_blink); > * > * This function never returns. > */ > -NORET_TYPE void panic(const char * fmt, ...) > +NORET_TYPE void panic(const char *fmt, ...) > +{ > + va_list ap; > + va_start(ap, fmt); > + vpanic(0, 0, fmt, ap); > +} > +EXPORT_SYMBOL(panic); > + > +NORET_TYPE void xpanic(enum panic_flags flags, int timeout, > + const char *fmt, ...) > +{ > + va_list ap; > + va_start(ap, fmt); > + xpanic(flags, timeout, fmt, ap);
Why are you calling xpanic() here again? I guess you meant vpanic().
> +} > +EXPORT_SYMBOL(xpanic); > + > +NORET_TYPE void vpanic(enum panic_flags flags, int timeout, > + const char * fmt, va_list args) > { > static char buf[1024]; > - va_list args; > long i, i_next = 0; > int state = 0; > > /* > + * Let user always override panic_timeout. > + */ > + if (panic_timeout > 0) > + timeout = panic_timeout; > + > + /* > * It's possible to come here directly from a panic-assertion and > * not have preempt disabled. Some functions called from here want > * preempt to be disabled. No point enabling it later though... > @@ -73,12 +96,11 @@ NORET_TYPE void panic(const char * fmt, > > console_verbose(); > bust_spinlocks(1); > - va_start(args, fmt); > vsnprintf(buf, sizeof(buf), fmt, args); > - va_end(args); > printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); > #ifdef CONFIG_DEBUG_BUGVERBOSE > - dump_stack(); > + if (!(flags & PANIC_NO_BACKTRACE)) > + dump_stack(); > #endif > > /* > @@ -86,7 +108,8 @@ NORET_TYPE void panic(const char * fmt, > * everything else. > * Do we want to call this before we try to display a message? > */ > - crash_kexec(NULL); > + if (!(flags & PANIC_NO_KEXEC)) > + crash_kexec(NULL); > > kmsg_dump(KMSG_DUMP_PANIC); > > @@ -104,7 +127,7 @@ NORET_TYPE void panic(const char * fmt, > if (!panic_blink) > panic_blink = no_blink; > > - if (panic_timeout > 0) { > + if (timeout > 0) { > /* > * Delay timeout seconds before rebooting the machine. > * We can't use the "normal" timers since we just panicked. > @@ -152,9 +175,7 @@ NORET_TYPE void panic(const char * fmt, > mdelay(PANIC_TIMER_STEP); > } > } > - > -EXPORT_SYMBOL(panic); > - > +EXPORT_SYMBOL(vpanic); > > struct tnt { > u8 bit; > -- > 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/ >
-- Thanks, //richard -- 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/
|  |