diff --git a/block/block-backend.c b/block/block-backend.c
index b48c91f4e1..d98a96ff37 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2576,14 +2576,25 @@ static void blk_root_drained_end(BdrvChild *child, int *drained_end_counter)
 
 bool blk_register_buf(BlockBackend *blk, void *host, size_t size, Error **errp)
 {
+    BlockDriverState *bs = blk_bs(blk);
+
     GLOBAL_STATE_CODE();
-    return bdrv_register_buf(blk_bs(blk), host, size, errp);
+
+    if (bs) {
+        return bdrv_register_buf(bs, host, size, errp);
+    }
+    return true;
 }
 
 void blk_unregister_buf(BlockBackend *blk, void *host, size_t size)
 {
+    BlockDriverState *bs = blk_bs(blk);
+
     GLOBAL_STATE_CODE();
-    bdrv_unregister_buf(blk_bs(blk), host, size);
+
+    if (bs) {
+        bdrv_unregister_buf(bs, host, size);
+    }
 }
 
 int coroutine_fn blk_co_copy_range(BlockBackend *blk_in, int64_t off_in,