--- a/xpcom/threads/TimerThread.cpp
+++ b/xpcom/threads/TimerThread.cpp
@@ -688,17 +688,17 @@ TimerThread::PostTimerEvent(already_AddR
 #ifdef MOZ_TASK_TRACER
   // During the dispatch of TimerEvent, we overwrite the current TraceInfo
   // partially with the info saved in timer earlier, and restore it back by
   // AutoSaveCurTraceInfo.
   AutoSaveCurTraceInfo saveCurTraceInfo;
   (timer->GetTracedTask()).SetTLSTraceInfo();
 #endif
 
-  nsIEventTarget* target = timer->mEventTarget;
+  nsCOMPtr<nsIEventTarget> target = timer->mEventTarget;
   event->SetTimer(timer.forget());
 
   nsresult rv;
   {
     // We release mMonitor around the Dispatch because if this timer is targeted
     // at the TimerThread we'll deadlock.
     MonitorAutoUnlock unlock(mMonitor);
     rv = target->Dispatch(event, NS_DISPATCH_NORMAL);