From: ebiederm@xmission.com (Eric W. Biederman)
To: Oleg Nesterov <oleg@redhat.com>
Cc: Greg Kurz <gkurz@fr.ibm.com>,
akpm@linux-foundation.org, containers@lists.osdl.org,
linux-kernel@vger.kernel.org, serge@hallyn.com,
daniel.lezcano@free.fr, xemul@openvz.org
Subject: Re: [PATCH] Introduce ActivePid: in /proc/self/status (v2, was Vpid:)
Date: Wed, 15 Jun 2011 12:08:23 -0700 [thread overview]
Message-ID: <m162o6lxp4.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <20110615184625.GA15573@redhat.com> (Oleg Nesterov's message of "Wed, 15 Jun 2011 20:46:25 +0200")
Oleg Nesterov <oleg@redhat.com> writes:
> On 06/15, Greg Kurz wrote:
>>
>> @@ -176,6 +177,17 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
>> if (tracer)
>> tpid = task_pid_nr_ns(tracer, ns);
>> }
>> + actpid = 0;
>> + sighand = rcu_dereference(p->sighand);
>> + if (sighand) {
>> + struct pid_namespace *pid_ns;
>> + unsigned long flags;
>> + spin_lock_irqsave(&sighand->siglock, flags);
>
> Well. This is not exactly right. We have lock_task_sighand() for this.
>
> But. Why do you need ->siglock? Why rcu_read_lock() is not enough?
>
> Hmm. You don't even need pid_ns afaics, you could simply look at
> pid->numbers[pid->level].
I got this moving in that direction, but I admit I probably didn't look
close enough. I just remember it is always tricky when accessing a
process and dealing with races with things like unhash_process().
Eric
next prev parent reply other threads:[~2011-06-15 19:08 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-15 14:55 [PATCH] Introduce ActivePid: in /proc/self/status (v2, was Vpid:) Greg Kurz
2011-06-15 18:46 ` Oleg Nesterov
2011-06-15 19:08 ` Eric W. Biederman [this message]
2011-06-16 11:01 ` Greg Kurz
2011-06-16 12:35 ` Louis Rilling
2011-06-16 13:00 ` Greg Kurz
2011-06-16 13:18 ` Oleg Nesterov
2011-06-16 13:25 ` Louis Rilling
2011-06-16 14:51 ` Oleg Nesterov
2011-06-16 15:08 ` Louis Rilling
2011-06-16 15:01 ` Greg Kurz
2011-06-16 15:27 ` Louis Rilling
2011-06-16 12:42 ` Oleg Nesterov
2011-06-15 19:03 ` Oleg Nesterov
2011-06-16 11:19 ` Greg Kurz
2011-06-16 12:25 ` Cedric Le Goater
2011-06-16 13:06 ` Oleg Nesterov
2011-06-16 14:25 ` Cedric Le Goater
2011-06-16 15:22 ` Eric W. Biederman
2011-06-16 16:22 ` Oleg Nesterov
2011-06-16 15:07 ` Eric W. Biederman
2011-06-16 15:33 ` Greg Kurz
2011-06-16 16:12 ` Oleg Nesterov
2011-06-16 12:52 ` Oleg Nesterov
2011-06-16 17:54 ` Bryan Donlan
2011-06-20 11:45 ` Greg Kurz
2011-06-20 17:37 ` Bryan Donlan
2011-06-20 22:44 ` Eric W. Biederman
2011-06-22 15:29 ` Greg Kurz
2011-06-23 0:39 ` Eric W. Biederman
2011-06-23 13:43 ` Greg Kurz
2011-06-23 14:37 ` Serge Hallyn
2011-06-22 15:00 ` Greg Kurz
2011-06-22 16:56 ` Bryan Donlan
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=m162o6lxp4.fsf@fess.ebiederm.org \
--to=ebiederm@xmission.com \
--cc=akpm@linux-foundation.org \
--cc=containers@lists.osdl.org \
--cc=daniel.lezcano@free.fr \
--cc=gkurz@fr.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=serge@hallyn.com \
--cc=xemul@openvz.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox