Fix hangs & crashes in teardown-during-Seek.

content/renderer/media/audio_renderer_impl.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/media/audio_renderer_impl.h"
 
 #include <math.h>
 
 #include <algorithm>
 
@@ skipping 80 matching lines @@
 
   bytes_per_second_ = params.GetBytesPerSecond();
 
   ChildProcess::current()->io_message_loop()->PostTask(
       FROM_HERE,
       NewRunnableMethod(this, &AudioRendererImpl::CreateStreamTask, params));
   return true;
 }
 
 void AudioRendererImpl::OnStop() {
-  base::AutoLock auto_lock(lock_);
-  if (stopped_)
-    return;
-  stopped_ = true;
+  // Since joining with the audio thread can acquire lock_, we make sure to
+  // Join() with it not under lock.
+  base::DelegateSimpleThread* audio_thread = NULL;
+  base::SyncSocket* socket = NULL;
+  {
+    base::AutoLock auto_lock(lock_);
+    if (stopped_)
+      return;
+    stopped_ = true;
+    DCHECK_EQ(!audio_thread_.get(), !socket_.get());
+    if (audio_thread_.get()) {
+      audio_thread = audio_thread_.get();
+      socket = socket_.get();
+    }
+    ChildProcess::current()->io_message_loop()->PostTask(
+        FROM_HERE,
+        NewRunnableMethod(this, &AudioRendererImpl::DestroyTask));
+  }
 
-  ChildProcess::current()->io_message_loop()->PostTask(
-      FROM_HERE,
-      NewRunnableMethod(this, &AudioRendererImpl::DestroyTask));
-
-  if (audio_thread_.get()) {
-    socket_->Close();
-    audio_thread_->Join();
+  if (audio_thread) {
+    CHECK(socket->Close());

[acolwell GONE FROM CHROMIUM, 2011/10/07 15:50:47]

Does this need to happen outside of the lock?

[Ami GONE FROM CHROMIUM, 2011/10/07 16:44:47]

Done.

+    audio_thread->Join();
   }
 }
 
 void AudioRendererImpl::NotifyDataAvailableIfNecessary() {
   if (latency_type_ == kHighLatency) {
     // Post a task to render thread to notify a packet reception.
     ChildProcess::current()->io_message_loop()->PostTask(
         FROM_HERE,
         NewRunnableMethod(this, &AudioRendererImpl::NotifyPacketReadyTask));
   }
@@ skipping 325 matching lines @@
   if (stopped_)
     return;
 
   stopped_ = true;
   DestroyTask();
 }
 
 // Our audio thread runs here. We receive requests for more data and send it
 // on this thread.
 void AudioRendererImpl::Run() {
+  DCHECK_EQ(kLowLatency, latency_type_);
   audio_thread_->SetThreadPriority(base::kThreadPriority_RealtimeAudio);
 
   int bytes;
   while (sizeof(bytes) == socket_->Receive(&bytes, sizeof(bytes))) {
     if (bytes == media::AudioOutputController::kPauseMark)
       continue;
     else if (bytes < 0)
       break;
     base::AutoLock auto_lock(lock_);
     if (stopped_)
@@ skipping 18 matching lines @@
     media::SetActualDataSizeInBytes(shared_memory_.get(),
                                     shared_memory_size_,
                                     size);
     UpdateEarliestEndTime(size, request_delay, time_now);
   }
 }
 
 void AudioRendererImpl::Send(IPC::Message* message) {
   filter_->Send(message);
 }