On 06/01, Mike Christie wrote:
>
> --- a/kernel/signal.c
> +++ b/kernel/signal.c
> @@ -1368,7 +1368,9 @@ int zap_other_threads(struct task_struct *p)
>
> while_each_thread(p, t) {
> task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
> - count++;
> + /* Don't require de_thread to wait for the vhost_worker */
> + if ((t->flags & (PF_IO_WORKER | PF_USER_WORKER)) !=
> PF_USER_WORKER)
> + count++;
Well if you do this, then you should also change __exit_signal() to
not decrement sig->notify_count. Otherwise de_thread() can succeed
before the "normal" sub-threads exit.
But this can't be right anyway... If nothing else, suppose we have
a process with 3 threads:
M - the main thread, group leader
T - sub-thread
V - vhost worker
T does exec and calls de_thread().
M exits. T takes the leadership and does release_task()
V is still running but V->group_leader points to already freed M.
Or unshare_sighand() after that... If nothing else this means that
lock_task_sighand(T) and lock_task_sighand(V) will take different
locks.
Oleg.
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