From: ebiederm@xmission.com (Eric W. Biederman)
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org,
Christof Meerwald <cmeerw@cmeerw.org>,
Linux Containers <containers@lists.linux-foundation.org>
Subject: Re: [PATCH] remove the no longer needed pid_alive() check in __task_pid_nr_ns()
Date: Tue, 21 Apr 2020 10:05:10 -0500 [thread overview]
Message-ID: <87mu74517d.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <20200421101904.GA9358@redhat.com> (Oleg Nesterov's message of "Tue, 21 Apr 2020 12:19:04 +0200")
Oleg Nesterov <oleg@redhat.com> writes:
> Starting from 2c4704756cab ("pids: Move the pgrp and session pid pointers
> from task_struct to signal_struct") __task_pid_nr_ns() doesn't dereference
> task->group_leader, we can remove the pid_alive() check.
>
> pid_nr_ns() has to check pid != NULL anyway, pid_alive() just adds the
> unnecessary confusion.
>
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
> ---
Good catch that does simplify things.
Eric
> kernel/pid.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> diff --git a/kernel/pid.c b/kernel/pid.c
> index bc21c0fb26d8..47221db038e2 100644
> --- a/kernel/pid.c
> +++ b/kernel/pid.c
> @@ -475,8 +475,7 @@ pid_t __task_pid_nr_ns(struct task_struct *task, enum pid_type type,
> rcu_read_lock();
> if (!ns)
> ns = task_active_pid_ns(current);
> - if (likely(pid_alive(task)))
> - nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
> + nr = pid_nr_ns(rcu_dereference(*task_pid_ptr(task, type)), ns);
> rcu_read_unlock();
>
> return nr;
next prev parent reply other threads:[~2020-04-21 15:08 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-19 20:13 SIGCHLD signal sometimes sent with si_pid==0 (Linux 5.6.5) Christof Meerwald
2020-04-20 17:05 ` [PATCH] signal: Avoid corrupting si_pid and si_uid in do_notify_parent Eric W. Biederman
2020-04-21 8:30 ` Christian Brauner
2020-04-21 9:28 ` Oleg Nesterov
2020-04-21 10:21 ` Christian Brauner
2020-04-21 11:11 ` Oleg Nesterov
2020-04-21 11:26 ` Christian Brauner
2020-04-21 12:17 ` Oleg Nesterov
2020-04-21 12:59 ` Christian Brauner
2020-04-21 13:42 ` Eric W. Biederman
2020-04-21 11:28 ` Oleg Nesterov
2020-04-21 11:38 ` Christian Brauner
2020-04-21 10:28 ` Christian Brauner
2020-04-21 14:57 ` Eric W. Biederman
2020-04-21 15:08 ` Christian Brauner
2020-04-21 9:04 ` Oleg Nesterov
2020-04-21 10:19 ` [PATCH] remove the no longer needed pid_alive() check in __task_pid_nr_ns() Oleg Nesterov
2020-04-21 10:50 ` Christian Brauner
2020-04-21 15:05 ` Eric W. Biederman [this message]
2020-04-24 18:05 ` Oleg Nesterov
2020-04-24 19:54 ` Eric W. Biederman
2020-04-21 14:59 ` SIGCHLD signal sometimes sent with si_pid==0 (Linux 5.6.5) Eric W. Biederman
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