[v1] ACPI: sleep: Avoid breaking S3 wakeup due to might_sleep()
Commit Message
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The addition of might_sleep() to down_timeout() caused the latter to
enable interrupts unconditionally in some cases, which in turn broke
the ACPI S3 wakeup path in acpi_suspend_enter(), where down_timeout()
is called by acpi_disable_all_gpes() via acpi_ut_acquire_mutex().
Namely, if CONFIG_DEBUG_ATOMIC_SLEEP is set, might_sleep() causes
might_resched() to be used and if CONFIG_PREEMPT_VOLUNTARY is set,
this triggers __cond_resched() which may call preempt_schedule_common(),
so __schedule() gets invoked and it ends up with enabled interrupts (in
the prev == next case).
Now, enabling interrupts early in the S3 wakeup path causes the kernel
to crash.
Address this by modifying acpi_suspend_enter() to disable GPEs without
attempting to acquire the sleeping lock which is not needed in that code
path anyway.
Fixes: 99409b935c9a locking/semaphore: Add might_sleep() to down_*() family
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
drivers/acpi/acpica/achware.h | 2 --
drivers/acpi/sleep.c | 16 ++++++++++++----
include/acpi/acpixf.h | 1 +
3 files changed, 13 insertions(+), 6 deletions(-)
Comments
On Tue, Jun 13, 2023 at 05:25:07PM +0200, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> The addition of might_sleep() to down_timeout() caused the latter to
> enable interrupts unconditionally in some cases, which in turn broke
> the ACPI S3 wakeup path in acpi_suspend_enter(), where down_timeout()
> is called by acpi_disable_all_gpes() via acpi_ut_acquire_mutex().
>
> Namely, if CONFIG_DEBUG_ATOMIC_SLEEP is set, might_sleep() causes
> might_resched() to be used and if CONFIG_PREEMPT_VOLUNTARY is set,
> this triggers __cond_resched() which may call preempt_schedule_common(),
> so __schedule() gets invoked and it ends up with enabled interrupts (in
> the prev == next case).
Urgh, so that code was relying on the lack of contention to not trigger
the schedule path -- with the added might_sleep() it triggers a
preemption point.
> Now, enabling interrupts early in the S3 wakeup path causes the kernel
> to crash.
>
> Address this by modifying acpi_suspend_enter() to disable GPEs without
> attempting to acquire the sleeping lock which is not needed in that code
> path anyway.
>
> Fixes: 99409b935c9a locking/semaphore: Add might_sleep() to down_*() family
$ git show -s --pretty='format:%h ("%s")' 99409b935c9a
99409b935c9a ("locking/semaphore: Add might_sleep() to down_*() family")
> Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> drivers/acpi/acpica/achware.h | 2 --
> drivers/acpi/sleep.c | 16 ++++++++++++----
> include/acpi/acpixf.h | 1 +
> 3 files changed, 13 insertions(+), 6 deletions(-)
>
> Index: linux-pm/drivers/acpi/acpica/achware.h
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpica/achware.h
> +++ linux-pm/drivers/acpi/acpica/achware.h
> @@ -101,8 +101,6 @@ acpi_status
> acpi_hw_get_gpe_status(struct acpi_gpe_event_info *gpe_event_info,
> acpi_event_status *event_status);
>
> -acpi_status acpi_hw_disable_all_gpes(void);
> -
> acpi_status acpi_hw_enable_all_runtime_gpes(void);
>
> acpi_status acpi_hw_enable_all_wakeup_gpes(void);
> Index: linux-pm/include/acpi/acpixf.h
> ===================================================================
> --- linux-pm.orig/include/acpi/acpixf.h
> +++ linux-pm/include/acpi/acpixf.h
> @@ -761,6 +761,7 @@ ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_sta
> acpi_event_status
> *event_status))
> ACPI_HW_DEPENDENT_RETURN_UINT32(u32 acpi_dispatch_gpe(acpi_handle gpe_device, u32 gpe_number))
> +ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_hw_disable_all_gpes(void))
> ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_disable_all_gpes(void))
> ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_enable_all_runtime_gpes(void))
> ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_enable_all_wakeup_gpes(void))
> Index: linux-pm/drivers/acpi/sleep.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/sleep.c
> +++ linux-pm/drivers/acpi/sleep.c
> @@ -636,11 +636,19 @@ static int acpi_suspend_enter(suspend_st
> }
>
> /*
> - * Disable and clear GPE status before interrupt is enabled. Some GPEs
> - * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
> - * acpi_leave_sleep_state will reenable specific GPEs later
> + * Disable all GPE and clear their status bits before interrupts are
> + * enabled. Some GPEs (like wakeup GPEs) have no handlers and this can
> + * prevent them from producing spurious interrups.
> + *
> + * acpi_leave_sleep_state() will reenable specific GPEs later.
> + *
> + * Because this code runs on one CPU with disabled interrupts (all of
> + * the other CPUs are offline at that time), it need not acquire any
> + * sleeping locks which maybe harmful due to instrumentation even if
> + * those locks are not contended, so avoid doing that by using a low-
> + * level library routine here.
I'm not sure I'd call the implicit preemption point 'instrumentation'
but yeah, fair enough I suppose.
> */
> - acpi_disable_all_gpes();
> + acpi_hw_disable_all_gpes();
> /* Allow EC transactions to happen. */
> acpi_ec_unblock_transactions();
>
>
>
>
On Wed, Jun 14, 2023 at 10:48 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Tue, Jun 13, 2023 at 05:25:07PM +0200, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> >
> > The addition of might_sleep() to down_timeout() caused the latter to
> > enable interrupts unconditionally in some cases, which in turn broke
> > the ACPI S3 wakeup path in acpi_suspend_enter(), where down_timeout()
> > is called by acpi_disable_all_gpes() via acpi_ut_acquire_mutex().
> >
> > Namely, if CONFIG_DEBUG_ATOMIC_SLEEP is set, might_sleep() causes
> > might_resched() to be used and if CONFIG_PREEMPT_VOLUNTARY is set,
> > this triggers __cond_resched() which may call preempt_schedule_common(),
> > so __schedule() gets invoked and it ends up with enabled interrupts (in
> > the prev == next case).
>
> Urgh, so that code was relying on the lack of contention to not trigger
> the schedule path -- with the added might_sleep() it triggers a
> preemption point.
Right.
> > Now, enabling interrupts early in the S3 wakeup path causes the kernel
> > to crash.
> >
> > Address this by modifying acpi_suspend_enter() to disable GPEs without
> > attempting to acquire the sleeping lock which is not needed in that code
> > path anyway.
> >
> > Fixes: 99409b935c9a locking/semaphore: Add might_sleep() to down_*() family
>
> $ git show -s --pretty='format:%h ("%s")' 99409b935c9a
> 99409b935c9a ("locking/semaphore: Add might_sleep() to down_*() family")
Right, thanks!
> > Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Thanks!
> > ---
> > drivers/acpi/acpica/achware.h | 2 --
> > drivers/acpi/sleep.c | 16 ++++++++++++----
> > include/acpi/acpixf.h | 1 +
> > 3 files changed, 13 insertions(+), 6 deletions(-)
> >
> > Index: linux-pm/drivers/acpi/acpica/achware.h
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/acpica/achware.h
> > +++ linux-pm/drivers/acpi/acpica/achware.h
> > @@ -101,8 +101,6 @@ acpi_status
> > acpi_hw_get_gpe_status(struct acpi_gpe_event_info *gpe_event_info,
> > acpi_event_status *event_status);
> >
> > -acpi_status acpi_hw_disable_all_gpes(void);
> > -
> > acpi_status acpi_hw_enable_all_runtime_gpes(void);
> >
> > acpi_status acpi_hw_enable_all_wakeup_gpes(void);
> > Index: linux-pm/include/acpi/acpixf.h
> > ===================================================================
> > --- linux-pm.orig/include/acpi/acpixf.h
> > +++ linux-pm/include/acpi/acpixf.h
> > @@ -761,6 +761,7 @@ ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_sta
> > acpi_event_status
> > *event_status))
> > ACPI_HW_DEPENDENT_RETURN_UINT32(u32 acpi_dispatch_gpe(acpi_handle gpe_device, u32 gpe_number))
> > +ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_hw_disable_all_gpes(void))
> > ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_disable_all_gpes(void))
> > ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_enable_all_runtime_gpes(void))
> > ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_enable_all_wakeup_gpes(void))
> > Index: linux-pm/drivers/acpi/sleep.c
> > ===================================================================
> > --- linux-pm.orig/drivers/acpi/sleep.c
> > +++ linux-pm/drivers/acpi/sleep.c
> > @@ -636,11 +636,19 @@ static int acpi_suspend_enter(suspend_st
> > }
> >
> > /*
> > - * Disable and clear GPE status before interrupt is enabled. Some GPEs
> > - * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
> > - * acpi_leave_sleep_state will reenable specific GPEs later
> > + * Disable all GPE and clear their status bits before interrupts are
> > + * enabled. Some GPEs (like wakeup GPEs) have no handlers and this can
> > + * prevent them from producing spurious interrups.
> > + *
> > + * acpi_leave_sleep_state() will reenable specific GPEs later.
> > + *
> > + * Because this code runs on one CPU with disabled interrupts (all of
> > + * the other CPUs are offline at that time), it need not acquire any
> > + * sleeping locks which maybe harmful due to instrumentation even if
> > + * those locks are not contended, so avoid doing that by using a low-
> > + * level library routine here.
>
> I'm not sure I'd call the implicit preemption point 'instrumentation'
> but yeah, fair enough I suppose.
OK, I'll send a v2 with this clarified.
> > */
> > - acpi_disable_all_gpes();
> > + acpi_hw_disable_all_gpes();
> > /* Allow EC transactions to happen. */
> > acpi_ec_unblock_transactions();
===================================================================
@@ -101,8 +101,6 @@ acpi_status
acpi_hw_get_gpe_status(struct acpi_gpe_event_info *gpe_event_info,
acpi_event_status *event_status);
-acpi_status acpi_hw_disable_all_gpes(void);
-
acpi_status acpi_hw_enable_all_runtime_gpes(void);
acpi_status acpi_hw_enable_all_wakeup_gpes(void);
===================================================================
@@ -761,6 +761,7 @@ ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_sta
acpi_event_status
*event_status))
ACPI_HW_DEPENDENT_RETURN_UINT32(u32 acpi_dispatch_gpe(acpi_handle gpe_device, u32 gpe_number))
+ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_hw_disable_all_gpes(void))
ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_disable_all_gpes(void))
ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_enable_all_runtime_gpes(void))
ACPI_HW_DEPENDENT_RETURN_STATUS(acpi_status acpi_enable_all_wakeup_gpes(void))
===================================================================
@@ -636,11 +636,19 @@ static int acpi_suspend_enter(suspend_st
}
/*
- * Disable and clear GPE status before interrupt is enabled. Some GPEs
- * (like wakeup GPE) haven't handler, this can avoid such GPE misfire.
- * acpi_leave_sleep_state will reenable specific GPEs later
+ * Disable all GPE and clear their status bits before interrupts are
+ * enabled. Some GPEs (like wakeup GPEs) have no handlers and this can
+ * prevent them from producing spurious interrups.
+ *
+ * acpi_leave_sleep_state() will reenable specific GPEs later.
+ *
+ * Because this code runs on one CPU with disabled interrupts (all of
+ * the other CPUs are offline at that time), it need not acquire any
+ * sleeping locks which maybe harmful due to instrumentation even if
+ * those locks are not contended, so avoid doing that by using a low-
+ * level library routine here.
*/
- acpi_disable_all_gpes();
+ acpi_hw_disable_all_gpes();
/* Allow EC transactions to happen. */
acpi_ec_unblock_transactions();