diff --git a/block.c b/block.c
index 2786e47d1e..4ea2c4f5c8 100644
--- a/block.c
+++ b/block.c
@@ -3220,9 +3220,7 @@ static void bdrv_dirty_bitmap_truncate(BlockDriverState *bs)
     uint64_t size = bdrv_nb_sectors(bs);
 
     QLIST_FOREACH(bitmap, &bs->dirty_bitmaps, list) {
-        if (bdrv_dirty_bitmap_frozen(bitmap)) {
-            continue;
-        }
+        assert(!bdrv_dirty_bitmap_frozen(bitmap));
         hbitmap_truncate(bitmap->bitmap, size);
         bitmap->size = size;
     }