SF: fix deadlock while switching resolution

Trying to grab mStateLock during kernelTimerChanged could lead to
deadlock when changing resolution as display gets recreated and the idle
timer may get stopped/re-started. The deadlock could happen when
calling OneShotTimer::stop() (due to thread join) in main thread while
kernelTimerChanged is waiting for lock.

Bug: 222755257
Test: cmd display set-user-preferred-display-mode
Change-Id: I0ccc7bccdcee98722c1dced09032ab3953d851cb

1 files changed, 1 insertions, 1 deletions

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index e8034de52c..350d7096aa 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -6063,7 +6063,6 @@ void SurfaceFlinger::kernelTimerChanged(bool expired) {
     static bool updateOverlay =
             property_get_bool("debug.sf.kernel_idle_timer_update_overlay", true);
     if (!updateOverlay) return;
-    if (Mutex::Autolock lock(mStateLock); !isRefreshRateOverlayEnabled()) return;
 
     // Update the overlay on the main thread to avoid race conditions with
     // mRefreshRateConfigs->getCurrentRefreshRate()
@@ -6073,6 +6072,7 @@ void SurfaceFlinger::kernelTimerChanged(bool expired) {
             ALOGW("%s: default display is null", __func__);
             return;
         }
+        if (!display->isRefreshRateOverlayEnabled()) return;
 
         const auto desiredActiveMode = display->getDesiredActiveMode();
         const std::optional<DisplayModeId> desiredModeId = desiredActiveMode