diff --git a/kernel/sys.c b/kernel/sys.c
index 47c30a20..5d0b44c 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -978,8 +978,7 @@
 		goto out;
 
 	if (task_pgrp(p) != pgrp) {
-		detach_pid(p, PIDTYPE_PGID);
-		attach_pid(p, PIDTYPE_PGID, pgrp);
+		change_pid(p, PIDTYPE_PGID, pgrp);
 		set_task_pgrp(p, pid_nr(pgrp));
 	}