From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <brauner@kernel.org>
Cc: linux-fsdevel@vger.kernel.org, Jeff Layton <jlayton@kernel.org>,
Lennart Poettering <lennart@poettering.net>,
Daan De Meyer <daan.j.demeyer@gmail.com>,
Mike Yuan <me@yhndnzj.com>,
linux-kernel@vger.kernel.org,
Peter Ziljstra <peterz@infradead.org>
Subject: Re: [PATCH v2 2/2] pidfs: ensure consistent ENOENT/ESRCH reporting
Date: Fri, 11 Apr 2025 15:54:45 +0200 [thread overview]
Message-ID: <20250411135445.GF5322@redhat.com> (raw)
In-Reply-To: <20250411-work-pidfs-enoent-v2-2-60b2d3bb545f@kernel.org>
For both patches:
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
a minor nit below...
On 04/11, Christian Brauner wrote:
>
> int pidfd_prepare(struct pid *pid, unsigned int flags, struct file **ret)
> {
> - int err = 0;
> -
> - if (!(flags & PIDFD_THREAD)) {
> + scoped_guard(spinlock_irq, &pid->wait_pidfd.lock) {
> + /*
> + * If this wasn't a thread-group leader struct pid or
> + * the task already been reaped report ESRCH to
> + * userspace.
> + */
> + if (!pid_has_task(pid, PIDTYPE_PID))
> + return -ESRCH;
The "If this wasn't a thread-group leader struct pid" part of the
comment looks a bit confusing to me, as if pid_has_task(PIDTYPE_PID)
should return false in this case.
OTOH, perhaps it makes sense to explain scoped_guard(wait_pidfd.lock)?
Something like "see unhash_process -> wake_up_all(), detach_pid(TGID)
isn't possible if pid_has_task(PID) succeeds".
Oleg.
next prev parent reply other threads:[~2025-04-11 13:55 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-11 13:22 [PATCH v2 0/2] pidfs: ensure consistent ENOENT/ESRCH reporting Christian Brauner
2025-04-11 13:22 ` [PATCH v2 1/2] exit: move wake_up_all() pidfd waiters into __unhash_process() Christian Brauner
2025-04-11 13:22 ` [PATCH v2 2/2] pidfs: ensure consistent ENOENT/ESRCH reporting Christian Brauner
2025-04-11 13:54 ` Oleg Nesterov [this message]
2025-04-11 15:14 ` Christian Brauner
2025-04-11 15:28 ` Oleg Nesterov
2025-04-15 22:34 ` [PATCH v2 0/2] " Nathan Chancellor
2025-04-16 13:55 ` Christian Brauner
2025-04-16 19:47 ` Christian Brauner
2025-04-16 20:21 ` Christian Brauner
2025-04-16 21:15 ` Nathan Chancellor
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