From: Oleg Nesterov <oleg@redhat.com>
To: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Cc: linux-kernel@vger.kernel.org,
Suren Baghdasaryan <surenb@google.com>,
kernel-team@android.com, Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christian Brauner <christian@brauner.io>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH RFC v1] pidfd: fix a race in setting exit_state for pidfd polling
Date: Fri, 19 Jul 2019 18:14:05 +0200 [thread overview]
Message-ID: <20190719161404.GA24170@redhat.com> (raw)
In-Reply-To: <20190717172100.261204-1-joel@joelfernandes.org>
it seems that I missed something else...
On 07/17, Joel Fernandes (Google) wrote:
>
> @@ -1156,10 +1157,11 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
> ptrace_unlink(p);
>
> /* If parent wants a zombie, don't release it now */
> - state = EXIT_ZOMBIE;
> + p->exit_state = EXIT_ZOMBIE;
> if (do_notify_parent(p, p->exit_signal))
> - state = EXIT_DEAD;
> - p->exit_state = state;
> + p->exit_state = EXIT_DEAD;
> +
> + state = p->exit_state;
> write_unlock_irq(&tasklist_lock);
why do you think we also need to change wait_task_zombie() ?
pidfd_poll() only needs the exit_state != 0 check, we know that it
is not zero at this point. Why do we need to change exit_state before
do_notify_parent() ?
Oleg.
next prev parent reply other threads:[~2019-07-19 16:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-17 17:21 [PATCH RFC v1] pidfd: fix a race in setting exit_state for pidfd polling Joel Fernandes (Google)
2019-07-17 17:55 ` Christian Brauner
2019-07-17 18:09 ` Suren Baghdasaryan
2019-07-17 20:47 ` Joel Fernandes
2019-07-18 10:09 ` Christian Brauner
2019-07-17 20:51 ` Joel Fernandes
2019-07-18 10:17 ` Christian Brauner
2019-07-18 16:05 ` Suren Baghdasaryan
2019-07-18 15:00 ` Oleg Nesterov
2019-07-19 16:14 ` Oleg Nesterov [this message]
2019-07-19 16:27 ` Christian Brauner
2019-07-19 16:33 ` Suren Baghdasaryan
2019-07-19 16:51 ` Joel Fernandes
2019-07-19 16:53 ` Christian Brauner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190719161404.GA24170@redhat.com \
--to=oleg@redhat.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=christian@brauner.io \
--cc=ebiederm@xmission.com \
--cc=joel@joelfernandes.org \
--cc=kernel-team@android.com \
--cc=linux-kernel@vger.kernel.org \
--cc=surenb@google.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.