diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 65726196d00082e20e29762dd5b68f03b0bfbc68..4dd78f9113853f8f947dfe326f58fe7c81104185 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -744,7 +744,7 @@ LockAcquireExtended(const LOCKTAG *locktag,
 		locallock->numLockOwners = 0;
 		locallock->maxLockOwners = 8;
 		locallock->holdsStrongLockCount = FALSE;
-		locallock->lockOwners = NULL;
+		locallock->lockOwners = NULL;	/* in case next line fails */
 		locallock->lockOwners = (LOCALLOCKOWNER *)
 			MemoryContextAlloc(TopMemoryContext,
 						  locallock->maxLockOwners * sizeof(LOCALLOCKOWNER));
@@ -1213,7 +1213,9 @@ RemoveLocalLock(LOCALLOCK *locallock)
 		if (locallock->lockOwners[i].owner != NULL)
 			ResourceOwnerForgetLock(locallock->lockOwners[i].owner, locallock);
 	}
-	pfree(locallock->lockOwners);
+	locallock->numLockOwners = 0;
+	if (locallock->lockOwners != NULL)
+		pfree(locallock->lockOwners);
 	locallock->lockOwners = NULL;
 
 	if (locallock->holdsStrongLockCount)