--- x/mm/filemap.c
+++ y/mm/filemap.c
@@ -3636,6 +3636,7 @@ static vm_fault_t filemap_map_folio_rang
 		continue;
 skip:
 		if (count) {
+			VM_WARN_ON_FOLIO(page_folio(page) != folio, folio);
 			set_pte_range(vmf, folio, page, count, addr);
 			*rss += count;
 			folio_ref_add(folio, count);