diff --git a/aos/common/util/thread.cc b/aos/common/util/thread.cc
index dbb638e..bfb1f51 100644
--- a/aos/common/util/thread.cc
+++ b/aos/common/util/thread.cc
@@ -24,10 +24,7 @@
 void Thread::Join() {
   CHECK(!joined_ && started_);
   joined_ = true;
-  {
-    MutexLocker locker(&should_terminate_mutex_);
-    should_terminate_ = true;
-  }
+  should_terminate_.store(true);
   CHECK(pthread_join(thread_, NULL) == 0);
 }