Messages in this thread | | | Date | Wed, 1 Feb 2023 20:56:55 -0800 | From | Eric Biggers <> | Subject | Re: [PATCH] sched/psi: fix use-after-free in ep_remove_wait_queue() |
| |
On Wed, Feb 01, 2023 at 07:00:23PM -0800, Munehisa Kamata wrote: > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c > index 8ac8b81bfee6..6e66c15f6450 100644 > --- a/kernel/sched/psi.c > +++ b/kernel/sched/psi.c > @@ -1343,10 +1343,11 @@ void psi_trigger_destroy(struct psi_trigger *t) > > group = t->group; > /* > - * Wakeup waiters to stop polling. Can happen if cgroup is deleted > - * from under a polling process. > + * Wakeup waiters to stop polling and clear the queue to prevent it from > + * being accessed later. Can happen if cgroup is deleted from under a > + * polling process otherwise. > */ > - wake_up_interruptible(&t->event_wait); > + wake_up_pollfree(&t->event_wait); > > mutex_lock(&group->trigger_lock);
wake_up_pollfree() should only be used in extremely rare cases. Why can't the lifetime of the waitqueue be fixed instead?
- Eric
| |