diff --git a/yarn/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala b/yarn/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
index 20fc19166ac4..f80aaf9e616b 100644
--- a/yarn/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
+++ b/yarn/src/main/scala/org/apache/spark/deploy/yarn/ApplicationMaster.scala
@@ -68,8 +68,8 @@ private[spark] class ApplicationMaster(
   @volatile private var finalMsg: String = ""
   @volatile private var userClassThread: Thread = _
 
-  private var reporterThread: Thread = _
-  private var allocator: YarnAllocator = _
+  @volatile private var reporterThread: Thread = _
+  @volatile private var allocator: YarnAllocator = _
 
   // Fields used in client mode.
   private var actorSystem: ActorSystem = null