libgui: New mutex for ConsumerBase frame callbacks

Adds a new mutex to protect ConsumerBase's mFrameAvailableListener
separately from the main mMutex. This prevents deadlocks when trying
to perform callbacks in response to other calls that come through
ConsumerBase.

Bug: 62915791
Test: EncodeVirtualDisplayWithCompositionTest#
          testRenderingMaxResolutionRemotely

Change-Id: I244dc2d83488e452d9690c0d7847c9ff15a95dbb
(cherry picked from commit 95971c8172495f7b6a0ede1a3508472b9a4e7b36)

3 files changed, 12 insertions, 5 deletions

diff --git a/include/gui/ConsumerBase.h b/include/gui/ConsumerBase.h
index 7912528ba7..891290bd42 100644
--- a/include/gui/ConsumerBase.h
+++ b/include/gui/ConsumerBase.h
@@ -241,7 +241,9 @@ protected:
 
     // mFrameAvailableListener is the listener object that will be called when a
     // new frame becomes available. If it is not NULL it will be called from
-    // queueBuffer.
+    // queueBuffer. The listener object is protected by mFrameAvailableMutex
+    // (not mMutex).
+    Mutex mFrameAvailableMutex;
     wp<FrameAvailableListener> mFrameAvailableListener;
 
     // The ConsumerBase has-a BufferQueue and is responsible for creating this object
diff --git a/libs/gui/ConsumerBase.cpp b/libs/gui/ConsumerBase.cpp
index c2b10a91dd..3d3637648c 100644
--- a/libs/gui/ConsumerBase.cpp
+++ b/libs/gui/ConsumerBase.cpp
@@ -106,7 +106,7 @@ void ConsumerBase::onFrameAvailable(const BufferItem& item) {
 
     sp<FrameAvailableListener> listener;
     { // scope for the lock
-        Mutex::Autolock lock(mMutex);
+        Mutex::Autolock lock(mFrameAvailableMutex);
         listener = mFrameAvailableListener.promote();
     }
 
@@ -121,7 +121,7 @@ void ConsumerBase::onFrameReplaced(const BufferItem &item) {
 
     sp<FrameAvailableListener> listener;
     {
-        Mutex::Autolock lock(mMutex);
+        Mutex::Autolock lock(mFrameAvailableMutex);
         listener = mFrameAvailableListener.promote();
     }
 
@@ -185,7 +185,7 @@ bool ConsumerBase::isAbandoned() {
 void ConsumerBase::setFrameAvailableListener(
         const wp<FrameAvailableListener>& listener) {
     CB_LOGV("setFrameAvailableListener");
-    Mutex::Autolock lock(mMutex);
+    Mutex::Autolock lock(mFrameAvailableMutex);
     mFrameAvailableListener = listener;
 }
 
diff --git a/services/surfaceflinger/SurfaceFlingerConsumer.cpp b/services/surfaceflinger/SurfaceFlingerConsumer.cpp
index 9babeef87f..abc8fde26b 100644
--- a/services/surfaceflinger/SurfaceFlingerConsumer.cpp
+++ b/services/surfaceflinger/SurfaceFlingerConsumer.cpp
@@ -240,10 +240,15 @@ void SurfaceFlingerConsumer::setContentsChangedListener(
 }
 
 void SurfaceFlingerConsumer::onSidebandStreamChanged() {
+    FrameAvailableListener* unsafeFrameAvailableListener = nullptr;
+    {
+        Mutex::Autolock lock(mFrameAvailableMutex);
+        unsafeFrameAvailableListener = mFrameAvailableListener.unsafe_get();
+    }
     sp<ContentsChangedListener> listener;
     {   // scope for the lock
         Mutex::Autolock lock(mMutex);
-        ALOG_ASSERT(mFrameAvailableListener.unsafe_get() == mContentsChangedListener.unsafe_get());
+        ALOG_ASSERT(unsafeFrameAvailableListener == mContentsChangedListener.unsafe_get());
         listener = mContentsChangedListener.promote();
     }