Fix race between Thread ctor/dtor and MessageQueueManager registrations.
This CL fixes a race where for Thread objects the parent MessageQueue
constructor registers the object in the MessageQueueManager even though
the Thread is not constructed completely yet. Same happens during
destruction.
BUG=webrtc:1225
Review URL: https://codereview.webrtc.org/1666863002
Cr-Commit-Position: refs/heads/master@{#11497}
diff --git a/webrtc/base/messagequeue.h b/webrtc/base/messagequeue.h
index 856a6eb..a7991a8 100644
--- a/webrtc/base/messagequeue.h
+++ b/webrtc/base/messagequeue.h
@@ -167,7 +167,18 @@
public:
static const int kForever = -1;
- explicit MessageQueue(SocketServer* ss = NULL);
+ // Create a new MessageQueue and optionally assign it to the passed
+ // SocketServer. Subclasses that override Clear should pass false for
+ // init_queue and call DoInit() from their constructor to prevent races
+ // with the MessageQueueManager using the object while the vtable is still
+ // being created.
+ explicit MessageQueue(SocketServer* ss = NULL,
+ bool init_queue = true);
+
+ // NOTE: SUBCLASSES OF MessageQueue THAT OVERRIDE Clear MUST CALL
+ // DoDestroy() IN THEIR DESTRUCTORS! This is required to avoid a data race
+ // between the destructor modifying the vtable, and the MessageQueueManager
+ // calling Clear on the object from a different thread.
virtual ~MessageQueue();
SocketServer* socketserver() { return ss_; }
@@ -241,6 +252,14 @@
uint32_t id,
MessageData* pdata);
+ // Perform initialization, subclasses must call this from their constructor
+ // if false was passed as init_queue to the MessageQueue constructor.
+ void DoInit();
+
+ // Perform cleanup, subclasses that override Clear must call this from the
+ // destructor.
+ void DoDestroy();
+
// The SocketServer is not owned by MessageQueue.
SocketServer* ss_;
// If a server isn't supplied in the constructor, use this one.
@@ -252,6 +271,8 @@
PriorityQueue dmsgq_;
uint32_t dmsgq_next_num_;
CriticalSection crit_;
+ bool fInitialized_;
+ bool fDestroyed_;
private:
RTC_DISALLOW_COPY_AND_ASSIGN(MessageQueue);