commit 194ff39de17ef4596b2b6ce1520516d7cc10fde6
author Josh Gao <jmgao@fb.com> Thu Sep 08 16:19:29 2022 -0700
committer Ying Wei <whisperwing@google.com> Thu Mar 30 18:01:58 2023 +0000
tree c4b412302c8bb831c1d13b95b1a4fa03e72667cb
parent a6e9dd2cb4da7f91f2379b44d3320cdb0f472f7c

SurfaceFlinger: add more thread-safety annotations.

As part of debugging a crash in SurfaceFlinger, we became suspicious of
markLayerPendingRemovalLocked because it wasn't annotated with thread
safety annotations. This ended up being a red herring, because
mStateLock is held on all paths into that function. Add some helpers to
MutexUtils.h to require/assert mutexes, and use them to sprinkle some
thread safety annotations to make things more clear.

Cherry-picked from aosp/2212955

Bug: 271644537
Test: m surfaceflinger
Change-Id: Ib48433765bb6ffcb351ec10cd5bc89e254b48545

services/surfaceflinger/SurfaceFlinger.cpp

diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index 9ceb0af..a538335 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -4769,6 +4769,7 @@
         }
         return 0;
     }
+    MUTEX_ALIAS(mStateLock, layer->mFlinger->mStateLock);
 
     ui::LayerStack oldLayerStack = layer->getLayerStack(LayerVector::StateSet::Current);
 
@@ -7739,6 +7740,7 @@
         ALOGD("Layer was destroyed soon after creation %p", state.layer.unsafe_get());
         return;
     }
+    MUTEX_ALIAS(mStateLock, layer->mFlinger->mStateLock);
 
     sp<Layer> parent;
     bool addToRoot = state.addToRoot;
@@ -7916,6 +7918,7 @@
             {
                 Mutex::Autolock lock(mStateLock);
                 createEffectLayer(mirrorArgs, &unused, &childMirror);
+                MUTEX_ALIAS(mStateLock, childMirror->mFlinger->mStateLock);
                 childMirror->setClonedChild(layer->createClone());
                 childMirror->reparent(mirrorDisplay.rootHandle);
             }