From 22db06337f590d01d79f60f181d8dfe5a9ef9085 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 14 Jun 2023 17:29:21 +0200 Subject: ACPI: sleep: Avoid breaking S3 wakeup due to might_sleep() 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 Signed-off-by: Rafael J. Wysocki Acked-by: Peter Zijlstra (Intel) Cc: 5.15+ # 5.15+ --- drivers/acpi/sleep.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'drivers/acpi/sleep.c') diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c index 72470b9f16c4..f32570f72b90 100644 --- a/drivers/acpi/sleep.c +++ b/drivers/acpi/sleep.c @@ -636,11 +636,19 @@ static int acpi_suspend_enter(suspend_state_t pm_state) } /* - * 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(); -- cgit v1.2.3