diff --git a/block/dirty-bitmap.c b/block/dirty-bitmap.c
index 6170f3a454..2139354230 100644
--- a/block/dirty-bitmap.c
+++ b/block/dirty-bitmap.c
@@ -825,6 +825,9 @@ void bdrv_merge_dirty_bitmap(BdrvDirtyBitmap *dest, const BdrvDirtyBitmap *src,
         goto out;
     }
 
+    if (bdrv_dirty_bitmap_check(src, BDRV_BITMAP_ALLOW_RO, errp)) {
+        goto out;
+    }
 
     if (!hbitmap_can_merge(dest->bitmap, src->bitmap)) {
         error_setg(errp, "Bitmaps are incompatible and can't be merged");