diff --git a/dom/workers/Worker.cpp b/dom/workers/Worker.cpp
index abddfa11c8a7..3452859c4c6d 100644
--- a/dom/workers/Worker.cpp
+++ b/dom/workers/Worker.cpp
@@ -86,6 +86,8 @@ void Worker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
   if (!mWorkerPrivate || mWorkerPrivate->ParentStatusProtected() > Running) {
     return;
   }
+  RefPtr<WorkerPrivate> workerPrivate = mWorkerPrivate;
+  Unused << workerPrivate;
 
   JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
 
@@ -145,6 +147,10 @@ void Worker::PostMessage(JSContext* aCx, JS::Handle<JS::Value> aMessage,
 
   runnable->Write(aCx, aMessage, transferable, clonePolicy, aRv);
 
+  if (!mWorkerPrivate || mWorkerPrivate->ParentStatusProtected() > Running) {
+    return;
+  }
+
   if (isTimelineRecording) {
     end = MakeUnique<WorkerTimelineMarker>(
         NS_IsMainThread()