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Commit 4402c153 authored by Jason Wessel's avatar Jason Wessel
Browse files

kdb,debug_core: Allow the debug core to receive a panic notification 



It is highly desirable to trap into kdb on panic.  The debug core will
attempt to register as the first in line for the panic notifier.

CC: Ingo Molnar <mingo@elte.hu>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
parent 5b778dad

kernel/debug/debug_core.c

+19 −0
Original line number Diff line number Diff line
@@ -762,11 +762,28 @@ 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,

       .priority	= INT_MAX,

};



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
@@ -786,6 +803,8 @@ 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);