Commit 2366e047 authored by Jason Wessel's avatar Jason Wessel
Browse files

kgdb,debug-core,gdbstub: Hook the reboot notifier for debugger detach 



The gdbstub and kdb should get detached if the system is rebooting.
Calling gdbstub_exit() will set the proper debug core state and send a
message to any debugger that is connected to correctly detach.

An attached debugger will receive the exit code from
include/linux/reboot.h based on SYS_HALT, SYS_REBOOT, etc...

Reported-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
parent 9fbe465e

kernel/debug/debug_core.c

+17 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ 
#include <linux/delay.h>

#include <linux/sched.h>

#include <linux/sysrq.h>

#include <linux/reboot.h>

#include <linux/init.h>

#include <linux/kgdb.h>

#include <linux/kdb.h>
@@ -784,6 +785,20 @@ void __init dbg_late_init(void) 
	kdb_init(KDB_INIT_FULL);

}



static int

dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)

{

	if (!dbg_kdb_mode)

		gdbstub_exit(code);

	return NOTIFY_DONE;

}



static struct notifier_block dbg_reboot_notifier = {

	.notifier_call		= dbg_notify_reboot,

	.next			= NULL,

	.priority		= INT_MAX,

};



static void kgdb_register_callbacks(void)

{

	if (!kgdb_io_module_registered) {
@@ -791,6 +806,7 @@ static void kgdb_register_callbacks(void) 
		kgdb_arch_init();

		if (!dbg_is_early)

			kgdb_arch_late();

		register_reboot_notifier(&dbg_reboot_notifier);

		atomic_notifier_chain_register(&panic_notifier_list,

					       &kgdb_panic_event_nb);

#ifdef CONFIG_MAGIC_SYSRQ
@@ -812,6 +828,7 @@ static void kgdb_unregister_callbacks(void) 
	 */

	if (kgdb_io_module_registered) {

		kgdb_io_module_registered = 0;

		unregister_reboot_notifier(&dbg_reboot_notifier);

		atomic_notifier_chain_unregister(&panic_notifier_list,

					       &kgdb_panic_event_nb);

		kgdb_arch_exit();

kernel/debug/gdbstub.c

+7 −0
Original line number Diff line number Diff line
@@ -1111,6 +1111,13 @@ void gdbstub_exit(int status) 
	unsigned char checksum, ch, buffer[3];

	int loop;



	if (!kgdb_connected)

		return;

	kgdb_connected = 0;



	if (!dbg_io_ops || dbg_kdb_mode)

		return;



	buffer[0] = 'W';

	buffer[1] = hex_asc_hi(status);

	buffer[2] = hex_asc_lo(status);

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