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

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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: 0e2110d2e910 ("kernel/reboot: Add kernel_can_power_off()")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Dmitry Osipenko 2022-05-25 00:21:18 +03:00 committed by Rafael J. Wysocki
parent cfd6d63e59
commit da007f171f
1 changed files with 17 additions and 16 deletions
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33
kernel/reboot.c
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@ -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;
}