[v2] 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>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
v1 -> v2:
* Rephrase the comment in acpi_suspend_enter() (Peter)
* Fix up the Fixes tag (Peter)
* Add Peter's ACK
---
drivers/acpi/acpica/achware.h | 2 --
drivers/acpi/sleep.c | 16 ++++++++++++----
include/acpi/acpixf.h | 1 +
3 files changed, 13 insertions(+), 6 deletions(-)
===================================================================
@@ -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 this time), it need not acquire any
+ * sleeping locks which may trigger an implicit preemption point even
+ * if there is no contention, 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();