* [PATCH v1] kernel/reboot: Fix powering off using a non-syscall code paths
@ 2022-06-06 16:56 Dmitry Osipenko
2022-06-07 17:44 ` Rafael J. Wysocki
0 siblings, 1 reply; 2+ messages in thread
From: Dmitry Osipenko @ 2022-06-06 16:56 UTC (permalink / raw)
To: Rafael J . Wysocki, Michael Ellerman
Cc: Geert Uytterhoeven, linux-kernel, linux-pm, linuxppc-dev
There are other methods of powering off machine than the reboot syscall.
Previously we missed to coved 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() to 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: da007f171fc9 ("kernel/reboot: Change registration order of legacy power-off handler")
Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
---
kernel/reboot.c | 46 ++++++++++++++++++++++++++--------------------
1 file changed, 26 insertions(+), 20 deletions(-)
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 3b19b123efec..b5a71d1ff603 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -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;
}
--
2.35.3
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v1] kernel/reboot: Fix powering off using a non-syscall code paths
2022-06-06 16:56 [PATCH v1] kernel/reboot: Fix powering off using a non-syscall code paths Dmitry Osipenko
@ 2022-06-07 17:44 ` Rafael J. Wysocki
0 siblings, 0 replies; 2+ messages in thread
From: Rafael J. Wysocki @ 2022-06-07 17:44 UTC (permalink / raw)
To: Dmitry Osipenko
Cc: Rafael J . Wysocki, Michael Ellerman, Geert Uytterhoeven,
Linux Kernel Mailing List, Linux PM, linuxppc-dev
On Mon, Jun 6, 2022 at 6:57 PM Dmitry Osipenko
<dmitry.osipenko@collabora.com> wrote:
>
> There are other methods of powering off machine than the reboot syscall.
> Previously we missed to coved 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() to 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: da007f171fc9 ("kernel/reboot: Change registration order of legacy power-off handler")
> Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
> ---
> kernel/reboot.c | 46 ++++++++++++++++++++++++++--------------------
> 1 file changed, 26 insertions(+), 20 deletions(-)
>
> diff --git a/kernel/reboot.c b/kernel/reboot.c
> index 3b19b123efec..b5a71d1ff603 100644
> --- a/kernel/reboot.c
> +++ b/kernel/reboot.c
> @@ -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;
> }
>
> --
Applied (with a couple of edits in the changelog), thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
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