Commit 2b8c612c authored by Dmitry Osipenko's avatar Dmitry Osipenko Committed by Rafael J. Wysocki
Browse files

kernel/reboot: Fix powering off using a non-syscall code paths 



There are other methods of powering off machine than the reboot syscall.
Previously we missed to cover those methods and it created power-off
regression for some machines, like the PowerPC e500.

Fix this problem by moving the legacy sys-off handler registration to
the latest phase of power-off process and making the kernel_can_power_off()
check the legacy pm_power_off presence.

Tested-by: Michael Ellerman <mpe@ellerman.id.au> # ppce500
Reported-by: Michael Ellerman <mpe@ellerman.id.au> # ppce500
Fixes: da007f17 ("kernel/reboot: Change registration order of legacy power-off handler")
Signed-off-by: default avatarDmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent 587b9bfe

kernel/reboot.c

+26 −20
Original line number Diff line number Diff line
@@ -320,6 +320,7 @@ static struct sys_off_handler platform_sys_off_handler; 
static struct sys_off_handler *alloc_sys_off_handler(int priority)

{

	struct sys_off_handler *handler;

	gfp_t flags;



	/*

	 * Platforms like m68k can't allocate sys_off handler dynamically
@@ -330,7 +331,12 @@ static struct sys_off_handler *alloc_sys_off_handler(int priority) 
		if (handler->cb_data)

			return ERR_PTR(-EBUSY);

	} else {

		handler = kzalloc(sizeof(*handler), GFP_KERNEL);

		if (system_state > SYSTEM_RUNNING)

			flags = GFP_ATOMIC;

		else

			flags = GFP_KERNEL;



		handler = kzalloc(sizeof(*handler), flags);

		if (!handler)

			return ERR_PTR(-ENOMEM);

	}
@@ -440,7 +446,7 @@ void unregister_sys_off_handler(struct sys_off_handler *handler) 
{

	int err;



	if (!handler)

	if (IS_ERR_OR_NULL(handler))

		return;



	if (handler->blocking)
@@ -615,7 +621,23 @@ static void do_kernel_power_off_prepare(void) 
 */

void do_kernel_power_off(void)

{

	struct sys_off_handler *sys_off = NULL;



	/*

	 * 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);



	atomic_notifier_call_chain(&power_off_handler_list, 0, NULL);



	unregister_sys_off_handler(sys_off);

}



/**
@@ -626,7 +648,8 @@ void do_kernel_power_off(void) 
 */

bool kernel_can_power_off(void)

{

	return !atomic_notifier_call_chain_is_empty(&power_off_handler_list);

	return !atomic_notifier_call_chain_is_empty(&power_off_handler_list) ||

		pm_power_off;

}

EXPORT_SYMBOL_GPL(kernel_can_power_off);
@@ -661,7 +684,6 @@ 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;
@@ -686,21 +708,6 @@ 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.

	 */
@@ -758,7 +765,6 @@ SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, 
		break;

	}

	mutex_unlock(&system_transition_mutex);

	unregister_sys_off_handler(sys_off);

	return ret;

}