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[4/8] PM: sleep: Fix possible overflow in pm_system_cancel_wakeup()

Message ID 2970489.lynJ6BP8VZ@kreacher (mailing list archive)
State Mainlined, archived
Headers show
Series PM / ACPI: sleep: Simplify the suspend-to-idle control flow | expand

Commit Message

Rafael J. Wysocki July 16, 2019, 4:14 p.m. UTC 
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It is not actually guaranteed that pm_abort_suspend will be
nonzero when pm_system_cancel_wakeup() is called which may lead to
subtle issues, so make it use atomic_dec_if_positive() instead of
atomic_dec() for the safety sake.

Fixes: 33e4f80ee69b ("ACPI / PM: Ignore spurious SCI wakeups from suspend-to-idle")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/base/power/wakeup.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

Index: linux-pm/drivers/base/power/wakeup.c
===================================================================
--- linux-pm.orig/drivers/base/power/wakeup.c
+++ linux-pm/drivers/base/power/wakeup.c
@@ -859,7 +859,7 @@  EXPORT_SYMBOL_GPL(pm_system_wakeup);
 
 void pm_system_cancel_wakeup(void)
 {
-	atomic_dec(&pm_abort_suspend);
+	atomic_dec_if_positive(&pm_abort_suspend);
 }
 
 void pm_wakeup_clear(bool reset)