Re: [PATCH v2 1/2] proc: Use PIDTYPE_TGID in next_tgid

Oleg Nesterov
2020-04-24T17:29:26Z

On 04/23, Eric W. Biederman wrote:
>
> @@ -3360,20 +3360,8 @@ static struct tgid_iter next_tgid(struct pid_namespace *ns, struct tgid_iter ite
> pid = find_ge_pid(iter.tgid, ns);
> if (pid) {
> iter.tgid = pid_nr_ns(pid, ns);
> - iter.task = pid_task(pid, PIDTYPE_PID);
> - /* What we to know is if the pid we have find is the
> - * pid of a thread_group_leader. Testing for task
> - * being a thread_group_leader is the obvious thing
> - * todo but there is a window when it fails, due to
> - * the pid transfer logic in de_thread.
> - *
> - * So we perform the straight forward test of seeing
> - * if the pid we have found is the pid of a thread
> - * group leader, and don't worry if the task we have
> - * found doesn't happen to be a thread group leader.
> - * As we don't care in the case of readdir.
> - */
> - if (!iter.task || !has_group_leader_pid(iter.task)) {
> + iter.task = pid_task(pid, PIDTYPE_TGID);
> + if (!iter.task) {
> iter.tgid += 1;
> goto retry;
> }

Acked-by: Oleg Nesterov <oleg@redhat.com>