Commit 37ad8aca authored Nov 21, 2011 by Tejun Heo

freezer: use lock_task_sighand() in fake_signal_wake_up()



cgroup_freezer calls freeze_task() without holding tasklist_lock and,
if the task is exiting, its ->sighand may be gone by the time
fake_signal_wake_up() is called.  Use lock_task_sighand() instead of
accessing ->sighand directly.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Paul Menage <paul@paulmenage.org>

parent 5ece3eae

kernel/freezer.c

+4 −3

Original line number	Diff line number	Diff line
		@@ -93,9 +93,10 @@ static void fake_signal_wake_up(struct task_struct *p)
		{
		unsigned long flags;

		spin_lock_irqsave(&p->sighand->siglock, flags);
		if (lock_task_sighand(p, &flags)) {
		signal_wake_up(p, 0);
		spin_unlock_irqrestore(&p->sighand->siglock, flags);
		unlock_task_sighand(p, &flags);
		}
		}

		/**