Commit 7a5e873f authored by Oleg Nesterov's avatar Oleg Nesterov Committed by Linus Torvalds
Browse files

signals: de_thread: simplify the ->child_reaper switching 



Now that we rely on SIGNAL_UNKILLABLE flag, de_thread() doesn't need the nasty
hack to kill the old ->child_reaper during the mt-exec.

This also means we can avoid taking tasklist_lock around zap_other_threads().

Signed-off-by: default avatarOleg Nesterov <oleg@tv-sign.ru>
Cc: Roland McGrath <roland@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fae5fa44

fs/exec.c

+2 −13
Original line number Diff line number Diff line
@@ -766,9 +766,7 @@ static int de_thread(struct task_struct *tsk) 


	/*

	 * Kill all other threads in the thread group.

	 * We must hold tasklist_lock to call zap_other_threads.

	 */

	read_lock(&tasklist_lock);

	spin_lock_irq(lock);

	if (signal_group_exit(sig)) {

		/*
@@ -776,21 +774,10 @@ static int de_thread(struct task_struct *tsk) 
		 * return so that the signal is processed.

		 */

		spin_unlock_irq(lock);

		read_unlock(&tasklist_lock);

		return -EAGAIN;

	}



	/*

	 * child_reaper ignores SIGKILL, change it now.

	 * Reparenting needs write_lock on tasklist_lock,

	 * so it is safe to do it under read_lock.

	 */

	if (unlikely(tsk->group_leader == task_child_reaper(tsk)))

		task_active_pid_ns(tsk)->child_reaper = tsk;



	sig->group_exit_task = tsk;

	zap_other_threads(tsk);

	read_unlock(&tasklist_lock);



	/* Account for the thread group leader hanging around: */

	count = thread_group_leader(tsk) ? 1 : 2;
@@ -821,6 +808,8 @@ static int de_thread(struct task_struct *tsk) 
			schedule();

		}



		if (unlikely(task_child_reaper(tsk) == leader))

			task_active_pid_ns(tsk)->child_reaper = tsk;

		/*

		 * The only record we have of the real-time age of a

		 * process, regardless of execs it's done, is start_time.

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