commit e4716f23a95e1ce35e71b9b850b2cd3d2c0f20d5
author Linus Nilsson <lnilsson@google.com> Fri Jul 10 16:07:57 2020 -0700
committer Linus Nilsson <lnilsson@google.com> Mon Jul 13 19:49:19 2020 -0700
tree c8ff2109361341bb1ac5c6809bb4f5231391e0de
parent daec9b4d36d1fb06811097117bfd673677bf5de1

Transcoder: Fix video track transcoding crash.

The VideoTrackTranscoder had a bug where the encoder could
outlive the transcoder object, because the encoder owns the
output buffers. This caused a crash when the encoder sent async
callbacks to the transcoder after it had been released. This fix
gives the encoder a weak reference to the transcoder and gives
outstanding buffers a strong reference to the encoder.

Fixes: 160711746
Test: Transcoder unit tests (build_and_run_all_unit_tests.sh).
Test: New unit test to trigger the crash before the fix.
Change-Id: I8141591399b6cff642d2d322809d3254adbefaaf

media/libmediatranscoding/transcoder/tests/MediaTrackTranscoderTests.cpp

diff --git a/media/libmediatranscoding/transcoder/tests/MediaTrackTranscoderTests.cpp b/media/libmediatranscoding/transcoder/tests/MediaTrackTranscoderTests.cpp
index 71d3a4e..502d5aa 100644
--- a/media/libmediatranscoding/transcoder/tests/MediaTrackTranscoderTests.cpp
+++ b/media/libmediatranscoding/transcoder/tests/MediaTrackTranscoderTests.cpp
@@ -53,7 +53,7 @@
 
         switch (GetParam()) {
         case VIDEO:
-            mTranscoder = std::make_shared<VideoTrackTranscoder>(mCallback);
+            mTranscoder = VideoTrackTranscoder::create(mCallback);
             break;
         case PASSTHROUGH:
             mTranscoder = std::make_shared<PassthroughTrackTranscoder>(mCallback);
@@ -164,8 +164,8 @@
     ASSERT_TRUE(mTranscoder->start());
     drainOutputSampleQueue();
     EXPECT_EQ(mCallback->waitUntilFinished(), AMEDIA_OK);
-    EXPECT_TRUE(mTranscoder->stop());
     joinDrainThread();
+    EXPECT_TRUE(mTranscoder->stop());
     EXPECT_FALSE(mQueueWasAborted);
     EXPECT_TRUE(mGotEndOfStream);
 }
@@ -232,9 +232,9 @@
     ASSERT_TRUE(mTranscoder->start());
     drainOutputSampleQueue();
     EXPECT_EQ(mCallback->waitUntilFinished(), AMEDIA_OK);
+    joinDrainThread();
     EXPECT_TRUE(mTranscoder->stop());
     EXPECT_FALSE(mTranscoder->start());
-    joinDrainThread();
     EXPECT_FALSE(mQueueWasAborted);
     EXPECT_TRUE(mGotEndOfStream);
 }
@@ -247,9 +247,8 @@
     mTranscoderOutputQueue->abort();
     drainOutputSampleQueue();
     EXPECT_EQ(mCallback->waitUntilFinished(), AMEDIA_ERROR_IO);
-    EXPECT_TRUE(mTranscoder->stop());
-
     joinDrainThread();
+    EXPECT_TRUE(mTranscoder->stop());
     EXPECT_TRUE(mQueueWasAborted);
     EXPECT_FALSE(mGotEndOfStream);
 }
@@ -265,8 +264,8 @@
 
     drainOutputSampleQueue();
     EXPECT_EQ(mCallback->waitUntilFinished(), AMEDIA_OK);
-    EXPECT_TRUE(mTranscoder->stop());
     joinDrainThread();
+    EXPECT_TRUE(mTranscoder->stop());
     EXPECT_FALSE(mQueueWasAborted);
     EXPECT_TRUE(mGotEndOfStream);