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: Jason Wessel <jason.wessel@windriver.com>

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: Jason Wessel <jason.wessel@windriver.com>
Jason Wessel
1 parent 5b778dadcd
Showing 1 changed file with 19 additions and 0 deletions Side-by-side Diff
kernel/debug/debug_core.c
@@ -762,11 +762,28 @@
 };
 #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 @@
 	 */
 	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);
...	...	@@ -762,11 +762,28 @@
762	762	};
763	763	#endif
764	764
	765	+static int kgdb_panic_event(struct notifier_block *self,
	766	+ unsigned long val,
	767	+ void *data)
	768	+{
	769	+ if (dbg_kdb_mode)
	770	+ kdb_printf("PANIC: %s\n", (char *)data);
	771	+ kgdb_breakpoint();
	772	+ return NOTIFY_DONE;
	773	+}
	774	+
	775	+static struct notifier_block kgdb_panic_event_nb = {
	776	+ .notifier_call = kgdb_panic_event,
	777	+ .priority = INT_MAX,
	778	+};
	779	+
765	780	static void kgdb_register_callbacks(void)
766	781	{
767	782	if (!kgdb_io_module_registered) {
768	783	kgdb_io_module_registered = 1;
769	784	kgdb_arch_init();
	785	+ atomic_notifier_chain_register(&panic_notifier_list,
	786	+ &kgdb_panic_event_nb);
770	787	#ifdef CONFIG_MAGIC_SYSRQ
771	788	register_sysrq_key('g', &sysrq_dbg_op);
772	789	#endif
...	...	@@ -786,6 +803,8 @@
786	803	*/
787	804	if (kgdb_io_module_registered) {
788	805	kgdb_io_module_registered = 0;
	806	+ atomic_notifier_chain_unregister(&panic_notifier_list,
	807	+ &kgdb_panic_event_nb);
789	808	kgdb_arch_exit();
790	809	#ifdef CONFIG_MAGIC_SYSRQ
791	810	unregister_sysrq_key('g', &sysrq_dbg_op);