diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c
index 1eb2d4b68da5bf1a5ee218f8e14535139f4f4c33..c377d384b765a7efa1d9483d53fe7f5855e1f42a 100644
--- a/src/backend/storage/lmgr/lock.c
+++ b/src/backend/storage/lmgr/lock.c
@@ -753,7 +753,7 @@ 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));
@@ -1222,7 +1222,9 @@ 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)