diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingReconstructionBlocks.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingReconstructionBlocks.java
index 0f20daae397..d0af60c6d2b 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingReconstructionBlocks.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/PendingReconstructionBlocks.java
@@ -132,7 +132,9 @@ class PendingReconstructionBlocks {
   public void clear() {
     synchronized (pendingReconstructions) {
       pendingReconstructions.clear();
-      timedOutItems.clear();
+      synchronized (timedOutItems) {
+        timedOutItems.clear();
+      }
       timedOutCount = 0L;
     }
   }