On Thu, Nov 30, 2023 at 06:39:39PM +0100, Oleg Nesterov wrote:
> Hi Tycho,
>
> I can't really read this patch now, possibly I am wrong, but...
No worries, no rush here.
> On 11/30, Tycho Andersen wrote:
> >
> > @@ -263,16 +263,25 @@ void release_task(struct task_struct *p)
> > */
> > zap_leader = 0;
> > leader = p->group_leader;
> > - if (leader != p && thread_group_empty(leader)
> > - && leader->exit_state == EXIT_ZOMBIE) {
> > - /*
> > - * If we were the last child thread and the leader has
> > - * exited already, and the leader's parent ignores SIGCHLD,
> > - * then we are the one who should release the leader.
> > - */
> > - zap_leader = do_notify_parent(leader, leader->exit_signal);
> > - if (zap_leader)
> > - leader->exit_state = EXIT_DEAD;
> > + if (leader != p) {
> > + if (thread_group_empty(leader)
> > + && leader->exit_state == EXIT_ZOMBIE) {
> > + /*
> > + * If we were the last child thread and the leader has
> > + * exited already, and the leader's parent ignores SIGCHLD,
> > + * then we are the one who should release the leader.
> > + */
> > + zap_leader = do_notify_parent(leader,
> > + leader->exit_signal);
> > + if (zap_leader)
> > + leader->exit_state = EXIT_DEAD;
> > + } else {
> > + /*
> > + * wake up pidfd pollers anyway, they want to know this
> > + * thread is dying.
> > + */
> > + wake_up_all(&thread_pid->wait_pidfd);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
> somehow I can't believe this is a good change after a quick glance ;)
Yeah, I figured it would raise some eyebrows :)
> I think that wake_up_all(wait_pidfd) should have a single caller,
> do_notify_pidfd(). This probably means it should be shiftef from
> do_notify_parent() to exit_notify(), I am not sure...
__exit_signals() is what I was thinking in the patch description, but
I'll look at exit_notify() too.
Tycho
