diff --git a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/UnsafeAccess.java b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/UnsafeAccess.java
index 275c750eb0a..72b1c1c7311 100644
--- a/hbase-common/src/main/java/org/apache/hadoop/hbase/util/UnsafeAccess.java
+++ b/hbase-common/src/main/java/org/apache/hadoop/hbase/util/UnsafeAccess.java
@@ -100,7 +100,7 @@ public final class UnsafeAccess {
   private static void unsafeCopy(Object src, long srcAddr, Object dst, long destAddr, long len) {
     while (len > 0) {
       long size = (len > UNSAFE_COPY_THRESHOLD) ? UNSAFE_COPY_THRESHOLD : len;
-      theUnsafe.copyMemory(src, srcAddr, dst, destAddr, len);
+      theUnsafe.copyMemory(src, srcAddr, dst, destAddr, size);
       len -= size;
       srcAddr += size;
       destAddr += size;