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authorRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-02-11 10:11:02 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-02-11 10:11:02 +0100
commite3728b50cd9be7d4b1469447cdf1feb93e3b7adb (patch)
tree446902616310615718c4615e9dbe1a1ea2e5a914 /kernel/power/suspend.c
parentf0ac20c3f6137910c8a927953e8a92f5b3716166 (diff)
ACPI: PM: s2idle: Avoid possible race related to the EC GPE
It is theoretically possible for the ACPI EC GPE to be set after the s2idle_ops->wake() called from s2idle_loop() has returned and before the subsequent pm_wakeup_pending() check is carried out. If that happens, the resulting wakeup event will cause the system to resume even though it may be a spurious one. To avoid that race, first make the ->wake() callback in struct platform_s2idle_ops return a bool value indicating whether or not to let the system resume and rearrange s2idle_loop() to use that value instad of the direct pm_wakeup_pending() call if ->wake() is present. Next, rework acpi_s2idle_wake() to process EC events and check pm_wakeup_pending() before re-arming the SCI for system wakeup to prevent it from triggering prematurely and add comments to that function to explain the rationale for the new code flow. Fixes: 56b991849009 ("PM: sleep: Simplify suspend-to-idle control flow") Cc: 5.4+ <stable@vger.kernel.org> # 5.4+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'kernel/power/suspend.c')
-rw-r--r--kernel/power/suspend.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c
index 2c47280fbfc7..8b1bb5ee7e5d 100644
--- a/kernel/power/suspend.c
+++ b/kernel/power/suspend.c
@@ -131,11 +131,12 @@ static void s2idle_loop(void)
* to avoid them upfront.
*/
for (;;) {
- if (s2idle_ops && s2idle_ops->wake)
- s2idle_ops->wake();
-
- if (pm_wakeup_pending())
+ if (s2idle_ops && s2idle_ops->wake) {
+ if (s2idle_ops->wake())
+ break;
+ } else if (pm_wakeup_pending()) {
break;
+ }
pm_wakeup_clear(false);