Commit da007f17 authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Rafael J. Wysocki
Browse files

kernel/reboot: Change registration order of legacy power-off handler 



We're unconditionally registering sys-off handler for the legacy
pm_power_off() callback, this causes problem for platforms that don't
use power-off handlers at all and should be halted. Now reboot syscall
assumes that there is a power-off handler installed and tries to power
off system instead of halting it.

To fix the trouble, move the handler's registration to the reboot syscall
and check the pm_power_off() presence.

Fixes: 0e2110d2 ("kernel/reboot: Add kernel_can_power_off()")
Reported-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Tested-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent cfd6d63e

kernel/reboot.c

+17 −16
Original line number Diff line number Diff line
@@ -569,22 +569,6 @@ static int legacy_pm_power_off(struct sys_off_data *data) 
	return NOTIFY_DONE;

}



/*

 * Register sys-off handlers for legacy PM callbacks. This allows legacy

 * PM callbacks co-exist with the new sys-off API.

 *

 * TODO: Remove legacy handlers once all legacy PM users will be switched

 *       to the sys-off based APIs.

 */

static int __init legacy_pm_init(void)

{

	register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT,

				 legacy_pm_power_off, NULL);



	return 0;

}

core_initcall(legacy_pm_init);



static void do_kernel_power_off_prepare(void)

{

	blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL);
@@ -646,6 +630,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, 
		void __user *, arg)

{

	struct pid_namespace *pid_ns = task_active_pid_ns(current);

	struct sys_off_handler *sys_off = NULL;

	char buffer[256];

	int ret = 0;
@@ -670,6 +655,21 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, 
	if (ret)

		return ret;



	/*

	 * Register sys-off handlers for legacy PM callback. This allows

	 * legacy PM callbacks temporary co-exist with the new sys-off API.

	 *

	 * TODO: Remove legacy handlers once all legacy PM users will be

	 *       switched to the sys-off based APIs.

	 */

	if (pm_power_off) {

		sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,

						   SYS_OFF_PRIO_DEFAULT,

						   legacy_pm_power_off, NULL);

		if (IS_ERR(sys_off))

			return PTR_ERR(sys_off);

	}



	/* Instead of trying to make the power_off code look like

	 * halt when pm_power_off is not set do it the easy way.

	 */
@@ -727,6 +727,7 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, 
		break;

	}

	mutex_unlock(&system_transition_mutex);

	unregister_sys_off_handler(sys_off);

	return ret;

}