diff --git a/block.c b/block.c
index f9cf05ddcf..a527aa1a4c 100644
--- a/block.c
+++ b/block.c
@@ -5200,7 +5200,7 @@ static void bdrv_close(BlockDriverState *bs)
         bs->drv = NULL;
     }
 
-    bdrv_graph_wrlock(NULL);
+    bdrv_graph_wrlock(bs);
     QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
         bdrv_unref_child(bs, child);
     }