commit 5d837eacdb9ba734d676a76b6ea73c4d596690fd
author Eric Laurent <elaurent@google.com> Fri Nov 15 18:56:01 2024 +0000
committer Eric Laurent <elaurent@google.com> Mon Nov 18 10:43:46 2024 +0000
tree 08249423ae70252f1d638e6fcca8a03cf0154955
parent ca2abe339a87087af08252c636ccc83335c5b468

AudioTrack: fix race condition between start and restore

There is a small window in AudioTrack::start where it is possible that
a concurrent track invalidation yields to rejecting the start request and leave
the track paused when later restored.
To avoid this race, return DEAD_OBJECT from AudioPolicyManager::startOutput()
if the output is already closed.

This aligns the behavior with startInput().

Also apply the same behavior to stopOutput() and stopInput() for consistency.
Apply the same fix to AudioRecord.

Bug: 367917846
Test: make
Flag: EXEMPT bug fix
Change-Id: I1c2051a2d7e58042cde5166914c68a081cd4bb49

services/audiopolicy/managerdefault/AudioPolicyManager.cpp

diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index 04ebb57..ef5f7a9 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -2350,7 +2350,7 @@
     sp<SwAudioOutputDescriptor> outputDesc = mOutputs.getOutputForClient(portId);
     if (outputDesc == 0) {
         ALOGW("startOutput() no output for client %d", portId);
-        return BAD_VALUE;
+        return DEAD_OBJECT;
     }
     sp<TrackClientDescriptor> client = outputDesc->getClient(portId);
 
@@ -2727,7 +2727,7 @@
     sp<SwAudioOutputDescriptor> outputDesc = mOutputs.getOutputForClient(portId);
     if (outputDesc == 0) {
         ALOGW("stopOutput() no output for client %d", portId);
-        return BAD_VALUE;
+        return DEAD_OBJECT;
     }
     sp<TrackClientDescriptor> client = outputDesc->getClient(portId);
 
@@ -3430,7 +3430,7 @@
     sp<AudioInputDescriptor> inputDesc = mInputs.getInputForClient(portId);
     if (inputDesc == 0) {
         ALOGW("%s no input for client %d", __FUNCTION__, portId);
-        return BAD_VALUE;
+        return DEAD_OBJECT;
     }
     audio_io_handle_t input = inputDesc->mIoHandle;
     sp<RecordClientDescriptor> client = inputDesc->getClient(portId);