From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Date: Mon, 15 Jul 2019 11:03:48 +0000 (+0200)
Subject: PM: sleep: Fix possible overflow in pm_system_cancel_wakeup()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=2933954b71f10d392764f95eec0f0aa2d103054b;p=linux.git

PM: sleep: Fix possible overflow in pm_system_cancel_wakeup()

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>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
---

diff --git a/drivers/base/power/wakeup.c b/drivers/base/power/wakeup.c
index ee31d4f8d856e..b30c45aad10f1 100644
--- a/drivers/base/power/wakeup.c
+++ b/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)