BufferQueue: Fix deadlock in setMaxAcquiredBufferCount
Uncovered this while testing. The deadlock happens when:
- ConsumerBase::setMaxAcquiredBufferCount locks itself
- Calls IGBC::setMaxAcquiredBufferCount, which can call
ConsumerListener::onBuffersReleased
- Which, in ConsumerBase, will take the lock again
Instead of this, we add a callback to be called instead of the
IConsumerListener. This callback is called on the same stack, with the
lock held, so that we can resolve everything atomically.
Bug: b/393639203
Flag: EXEMPT small cleanup
Test: new test
Change-Id: Iddd8f902d1fd0aeed6aac095eaa6c0b870ffff70
diff --git a/libs/gui/ConsumerBase.cpp b/libs/gui/ConsumerBase.cpp
index 117a362..5b89c6e 100644
--- a/libs/gui/ConsumerBase.cpp
+++ b/libs/gui/ConsumerBase.cpp
@@ -264,7 +264,10 @@
void ConsumerBase::onBuffersReleased() {
Mutex::Autolock lock(mMutex);
+ onBuffersReleasedLocked();
+}
+void ConsumerBase::onBuffersReleasedLocked() {
CB_LOGV("onBuffersReleased");
if (mAbandoned) {
@@ -481,7 +484,8 @@
CB_LOGE("setMaxAcquiredBufferCount: ConsumerBase is abandoned!");
return NO_INIT;
}
- return mConsumer->setMaxAcquiredBufferCount(maxAcquiredBuffers);
+ return mConsumer->setMaxAcquiredBufferCount(maxAcquiredBuffers,
+ {[this]() { onBuffersReleasedLocked(); }});
}
status_t ConsumerBase::setConsumerIsProtected(bool isProtected) {