It is highly desirable to trap into kdb on panic, and in order to do so the notifier must be called before smp_send_stop(), else the debug_core will not be able to correctly trap all the CPUs.
CC: Ingo Molnar <[email protected]> CC: Andrew Morton <[email protected]> Signed-off-by: Jason Wessel <[email protected]> --- include/linux/kdb.h | 1 + kernel/debug/debug_core.c | 19 +++++++++++++++++++ kernel/panic.c | 7 ++++--- 3 files changed, 24 insertions(+), 3 deletions(-) diff --git a/include/linux/kdb.h b/include/linux/kdb.h index 387a916..3504c1c 100644 --- a/include/linux/kdb.h +++ b/include/linux/kdb.h @@ -114,5 +114,6 @@ extern void kdb_si_swapinfo(struct sysinfo *); #else /* ! CONFIG_KGDB_KDB */ #define KDB_IS_RUNNING() (0) +#define kdb_printf(...) #endif /* CONFIG_KGDB_KDB */ #endif /* !_KDB_H */ diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index e6c6f8a..b28a0a4 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -46,6 +46,7 @@ #include <linux/pid.h> #include <linux/smp.h> #include <linux/mm.h> +#include <linux/kdb.h> #include <asm/cacheflush.h> #include <asm/byteorder.h> @@ -750,11 +751,27 @@ static struct sysrq_key_op sysrq_dbg_op = { }; #endif +static int kgdb_panic_event(struct notifier_block *self, + unsigned long val, + void *data) +{ + if (dbg_kdb_mode) + kdb_printf("PANIC: %s\n", (char *)data); + kgdb_breakpoint(); + return NOTIFY_DONE; +} + +static struct notifier_block kgdb_panic_event_nb = { + .notifier_call = kgdb_panic_event, +}; + static void kgdb_register_callbacks(void) { if (!kgdb_io_module_registered) { kgdb_io_module_registered = 1; kgdb_arch_init(); + atomic_notifier_chain_register(&panic_notifier_list, + &kgdb_panic_event_nb); #ifdef CONFIG_MAGIC_SYSRQ register_sysrq_key('g', &sysrq_dbg_op); #endif @@ -774,6 +791,8 @@ static void kgdb_unregister_callbacks(void) */ if (kgdb_io_module_registered) { kgdb_io_module_registered = 0; + atomic_notifier_chain_unregister(&panic_notifier_list, + &kgdb_panic_event_nb); kgdb_arch_exit(); #ifdef CONFIG_MAGIC_SYSRQ unregister_sysrq_key('g', &sysrq_dbg_op); diff --git a/kernel/panic.c b/kernel/panic.c index 5827f7b..1f4fb47 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -66,10 +66,13 @@ NORET_TYPE void panic(const char * fmt, ...) */ preempt_disable(); - bust_spinlocks(1); va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); + + atomic_notifier_call_chain(&panic_notifier_list, 0, buf); + + bust_spinlocks(1); printk(KERN_EMERG "Kernel panic - not syncing: %s\n",buf); #ifdef CONFIG_DEBUG_BUGVERBOSE dump_stack(); @@ -90,8 +93,6 @@ NORET_TYPE void panic(const char * fmt, ...) */ smp_send_stop(); - atomic_notifier_call_chain(&panic_notifier_list, 0, buf); - bust_spinlocks(0); if (!panic_blink) -- 1.6.4.rc1 ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Kgdb-bugreport mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/kgdb-bugreport
