+ else {
+ /*
+ * The SIGALRM timer survives the exec, but needs to point
+ * at us as the new group leader now. We have a race with
+ * a timer firing now getting the old leader, so we need to
+ * synchronize with any firing (by calling del_timer_sync)
+ * before we can safely let the old group leader die.
+ */
+ sig->real_timer.data = (unsigned long)current;
+ if (del_timer_sync(&sig->real_timer))
+ add_timer(&sig->real_timer);
+ }