diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 8b5dcb82a81..77de95d3593 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -644,7 +644,7 @@ LockAcquireExtended(const LOCKTAG *locktag,
 		locallock->nLocks = 0;
 		locallock->numLockOwners = 0;
 		locallock->maxLockOwners = 8;
-		locallock->lockOwners = NULL;
+		locallock->lockOwners = NULL;	/* in case next line fails */
 		locallock->lockOwners = (LOCALLOCKOWNER *)
 			MemoryContextAlloc(TopMemoryContext,
 						  locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
@@ -994,8 +994,11 @@ LockAcquireExtended(const LOCKTAG *locktag,
 static void
 RemoveLocalLock(LOCALLOCK *locallock)
 {
-	pfree(locallock->lockOwners);
+	locallock->numLockOwners = 0;
+	if (locallock->lockOwners != NULL)
+		pfree(locallock->lockOwners);
 	locallock->lockOwners = NULL;
+
 	if (!hash_search(LockMethodLocalHash,
 					 (void *) &(locallock->tag),
 					 HASH_REMOVE, NULL))