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

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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: da007f171f ("kernel/reboot: Change registration order of legacy power-off handler")
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 2022-06-06 19:56:40 +03:00 • committed by Rafael J. Wysocki
parent 587b9bfe06
commit 2b8c612c61
1 changed files with 26 additions and 20 deletions
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46
kernel/reboot.c
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@ -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;
}