From 15ad2470b2f2ac34473eb568b606ad75e8e63ac6 Mon Sep 17 00:00:00 2001 From: Zhijun He Date: Fri, 11 Oct 2013 16:21:11 -0700 Subject: Camera: Fix deadlock in Camera3OutputStream process capture request thread, process capture result and setParameter binder threads can run into circular locking situation when acquiring StreamingProcessor lock, Camera3Stream lock, and bufferQueue lock. Releasing the Camera3Stream lock briefly in process capture request thread getbuffer call can break this deadlock. Bug: 11016037 Change-Id: If08d4b134c26be26039b1d5363759e60f911bad6 --- .../libcameraservice/device3/Camera3OutputStream.cpp | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-) diff --git a/services/camera/libcameraservice/device3/Camera3OutputStream.cpp b/services/camera/libcameraservice/device3/Camera3OutputStream.cpp index 41328fc..682755d 100644 --- a/services/camera/libcameraservice/device3/Camera3OutputStream.cpp +++ b/services/camera/libcameraservice/device3/Camera3OutputStream.cpp @@ -92,7 +92,22 @@ status_t Camera3OutputStream::getBufferLocked(camera3_stream_buffer *buffer) { ANativeWindowBuffer* anb; int fenceFd; - res = mConsumer->dequeueBuffer(mConsumer.get(), &anb, &fenceFd); + /** + * Release the lock briefly to avoid deadlock for below scenario: + * Thread 1: StreamingProcessor::startStream -> Camera3Stream::isConfiguring(). + * This thread acquired StreamingProcessor lock and try to lock Camera3Stream lock. + * Thread 2: Camera3Stream::returnBuffer->StreamingProcessor::onFrameAvailable(). + * This thread acquired Camera3Stream lock and bufferQueue lock, and try to lock + * StreamingProcessor lock. + * Thread 3: Camera3Stream::getBuffer(). This thread acquired Camera3Stream lock + * and try to lock bufferQueue lock. + * Then there is circular locking dependency. + */ + sp currentConsumer = mConsumer; + mLock.unlock(); + + res = currentConsumer->dequeueBuffer(currentConsumer.get(), &anb, &fenceFd); + mLock.lock(); if (res != OK) { ALOGE("%s: Stream %d: Can't dequeue next output buffer: %s (%d)", __FUNCTION__, mId, strerror(-res), res); -- cgit v1.1