diff --git a/core/src/main/java/org/apache/spark/memory/TaskMemoryManager.java b/core/src/main/java/org/apache/spark/memory/TaskMemoryManager.java
index d31eb449eb82..d2a88864f7ac 100644
--- a/core/src/main/java/org/apache/spark/memory/TaskMemoryManager.java
+++ b/core/src/main/java/org/apache/spark/memory/TaskMemoryManager.java
@@ -312,7 +312,7 @@ public static long encodePageNumberAndOffset(int pageNumber, long offsetInPage)
 
   @VisibleForTesting
   public static int decodePageNumber(long pagePlusOffsetAddress) {
-    return (int) ((pagePlusOffsetAddress & MASK_LONG_UPPER_13_BITS) >>> OFFSET_BITS);
+    return (int) (pagePlusOffsetAddress >>> OFFSET_BITS);
   }
 
   private static long decodeOffset(long pagePlusOffsetAddress) {