kgdb: Add module event hooks

Allow gdb to auto load kernel modules when it is attached, which makes it trivially easy to debug module init functions or pre-set breakpoints in a kernel module that has not loaded yet. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>

kgdb: Add module event hooks
Allow gdb to auto load kernel modules when it is attached, which makes it trivially easy to debug module init functions or pre-set breakpoints in a kernel module that has not loaded yet. Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Jason Wessel
1 parent a0d271cbfe
Showing 1 changed file with 18 additions and 0 deletions Side-by-side Diff
kernel/debug/debug_core.c
@@ -688,6 +688,22 @@
 	return kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
 }
  
+/*
+ * GDB places a breakpoint at this function to know dynamically
+ * loaded objects. It's not defined static so that only one instance with this
+ * name exists in the kernel.
+ */
+
+static int module_event(struct notifier_block *self, unsigned long val,
+	void *data)
+{
+	return 0;
+}
+
+static struct notifier_block dbg_module_load_nb = {
+	.notifier_call	= module_event,
+};
+
 int kgdb_nmicallback(int cpu, void *regs)
 {
 #ifdef CONFIG_SMP
@@ -816,6 +832,7 @@
 		kgdb_arch_init();
 		if (!dbg_is_early)
 			kgdb_arch_late();
+		register_module_notifier(&dbg_module_load_nb);
 		register_reboot_notifier(&dbg_reboot_notifier);
 		atomic_notifier_chain_register(&panic_notifier_list,
 					       &kgdb_panic_event_nb);
@@ -839,6 +856,7 @@
 	if (kgdb_io_module_registered) {
 		kgdb_io_module_registered = 0;
 		unregister_reboot_notifier(&dbg_reboot_notifier);
+		unregister_module_notifier(&dbg_module_load_nb);
 		atomic_notifier_chain_unregister(&panic_notifier_list,
 					       &kgdb_panic_event_nb);
 		kgdb_arch_exit();
...	...	@@ -688,6 +688,22 @@
688	688	return kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
689	689	}
690	690
	691	+/*
	692	+ * GDB places a breakpoint at this function to know dynamically
	693	+ * loaded objects. It's not defined static so that only one instance with this
	694	+ * name exists in the kernel.
	695	+ */
	696	+
	697	+static int module_event(struct notifier_block *self, unsigned long val,
	698	+ void *data)
	699	+{
	700	+ return 0;
	701	+}
	702	+
	703	+static struct notifier_block dbg_module_load_nb = {
	704	+ .notifier_call = module_event,
	705	+};
	706	+
691	707	int kgdb_nmicallback(int cpu, void *regs)
692	708	{
693	709	#ifdef CONFIG_SMP
...	...	@@ -816,6 +832,7 @@
816	832	kgdb_arch_init();
817	833	if (!dbg_is_early)
818	834	kgdb_arch_late();
	835	+ register_module_notifier(&dbg_module_load_nb);
819	836	register_reboot_notifier(&dbg_reboot_notifier);
820	837	atomic_notifier_chain_register(&panic_notifier_list,
821	838	&kgdb_panic_event_nb);
...	...	@@ -839,6 +856,7 @@
839	856	if (kgdb_io_module_registered) {
840	857	kgdb_io_module_registered = 0;
841	858	unregister_reboot_notifier(&dbg_reboot_notifier);
	859	+ unregister_module_notifier(&dbg_module_load_nb);
842	860	atomic_notifier_chain_unregister(&panic_notifier_list,
843	861	&kgdb_panic_event_nb);
844	862	kgdb_arch_exit();