diff --git a/core/src/main/scala/org/apache/spark/util/collection/ExternalSorter.scala b/core/src/main/scala/org/apache/spark/util/collection/ExternalSorter.scala
index 708a0070e2253..7c98e8cabb229 100644
--- a/core/src/main/scala/org/apache/spark/util/collection/ExternalSorter.scala
+++ b/core/src/main/scala/org/apache/spark/util/collection/ExternalSorter.scala
@@ -611,7 +611,9 @@ private[spark] class ExternalSorter[K, V, C](
       val ds = deserializeStream
       deserializeStream = null
       fileStream = null
-      ds.close()
+      if (ds != null) {
+        ds.close()
+      }
       // NOTE: We don't do file.delete() here because that is done in ExternalSorter.stop().
       // This should also be fixed in ExternalAppendOnlyMap.
     }