diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index bbf7f20bd..80549d1b7 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -246,7 +246,7 @@ static void make_device(char *path, int delete)
 
 			/* 2nd field: uid:gid - device ownership */
 			if (get_uidgid(&ugid, tokens[1], 1) == 0)
-				bb_error_msg("unknown user/group %s", tokens[1]);
+				bb_error_msg("unknown user/group %s on line %d", tokens[1], parser->lineno);
 
 			/* 3rd field: mode - device permissions */
 			/* mode = strtoul(tokens[2], NULL, 8); */