Fix a race condition in signal thread destructor.

BUG=23251
TEST=none

Review URL: http://codereview.chromium.org/402026

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@32211 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 14 insertions, 2 deletions

diff --git a/third_party/libjingle/files/talk/base/signalthread.cc b/third_party/libjingle/files/talk/base/signalthread.cc
index 919d1c3..0b5154d6 100644
--- a/third_party/libjingle/files/talk/base/signalthread.cc
+++ b/third_party/libjingle/files/talk/base/signalthread.cc
@@ -10,10 +10,11 @@ using namespace talk_base;
 SignalThread::SignalThread()
 : main_(Thread::Current()), state_(kInit)
 {
-  worker_.parent_ = this;
+  worker_.SetParent(this);
 }
 
 SignalThread::~SignalThread() {
+  worker_.SetParent(NULL);
 }
 
 void SignalThread::SetPriority(ThreadPriority priority) {
diff --git a/third_party/libjingle/files/talk/base/signalthread.h b/third_party/libjingle/files/talk/base/signalthread.h
index 9e6bd05..ccba912 100644
--- a/third_party/libjingle/files/talk/base/signalthread.h
+++ b/third_party/libjingle/files/talk/base/signalthread.h
@@ -73,8 +73,19 @@ private:
   friend class Worker;
   class Worker : public Thread {
   public:
+    virtual void Run() {
+      CritScope cs(&parent_crit_);
+      if (parent_)
+        parent_->Run();
+    }
+    void SetParent(SignalThread* parent) {
+      CritScope cs(&parent_crit_);
+      parent_ = parent;
+    }
+
+  private:
     SignalThread* parent_;
-    virtual void Run() { parent_->Run(); }
+    CriticalSection parent_crit_;
   };
 
   void Run();