--- usr.sbin/pw/pw_user.c.orig	2017-03-20 17:40:09.225608000 +0700
+++ usr.sbin/pw/pw_user.c	2017-03-27 17:34:13.874059000 +0700
@@ -1083,10 +1083,10 @@ split_groups(StringList **groups, char *
 	char *p;
 	char tok[] = ", \t";
 
+	if (*groups == NULL)
+		*groups = sl_init();
 	for (p = strtok(groupsstr, tok); p != NULL; p = strtok(NULL, tok)) {
 		grp = group_from_name_or_id(p);
-		if (*groups == NULL)
-			*groups = sl_init();
 		sl_add(*groups, newstr(grp->gr_name));
 	}
 }