diff --git a/fs/unicode/utf8-norm.c b/fs/unicode/utf8-norm.c
index 20d440c3f2db26a5f1dfe41d6ae8fcca2caac935..801ed6d2ea3788a5c518d86c9336bd573dfe506c 100644
--- a/fs/unicode/utf8-norm.c
+++ b/fs/unicode/utf8-norm.c
@@ -714,6 +714,8 @@ int utf8byte(struct utf8cursor *u8c)
 			}
 
 			leaf = utf8lookup(u8c->data, u8c->hangul, u8c->s);
+			if (!leaf)
+				return -1;
 			ccc = LEAF_CCC(leaf);
 		}