From: Oleg Nesterov <oleg@redhat.com>
To: Ben Blum <bblum@andrew.cmu.edu>
Cc: Paul Menage <menage@google.com>,
linux-kernel@vger.kernel.org,
containers@lists.linux-foundation.org, akpm@linux-foundation.org,
ebiederm@xmission.com, lizf@cn.fujitsu.com, matthltc@us.ibm.com
Subject: Re: [RFC] [PATCH 2/2] cgroups: make procs file writable
Date: Thu, 3 Jun 2010 16:48:10 +0200 [thread overview]
Message-ID: <20100603144810.GB6284@redhat.com> (raw)
In-Reply-To: <20100603044001.GA21006@ghc02.ghc.andrew.cmu.edu>
On 06/03, Ben Blum wrote:
>
> On Wed, Jun 02, 2010 at 10:58:55PM +0200, Oleg Nesterov wrote:
> > Hmm. The usage of ->thread_group in ->can_attach() methods doesn't
> > look safe to me... but currently bool threadgroup is always false.
>
> I recall putting a rcu_read_lock() around that part and being assured
> that made it safe. But I don't remember the details. Maybe taking
> tasklist_lock is necessary?
rcu_read_lock() is not enough, see another email I sent.
Once again.
rcu_read_lock()
list_for_each_rcu(tsk->thread_group)
assumes that at least tsk->thread_group->next can't point to nowhere,
this is not true. This memory can go away _before_ we take rcu lock.
Oleg.
next prev parent reply other threads:[~2010-06-03 14:50 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-30 1:30 [RFC] [PATCH v2 0/2] cgroups: implement moving a threadgroup's threads atomically with cgroup.procs Ben Blum
2010-05-30 1:30 ` Ben Blum
[not found] ` <20100530013002.GA762-kwnxxEB+oiWqwBT9kiuFm8WGCVk0P7UB@public.gmane.org>
2010-05-30 1:31 ` [RFC] [PATCH 1/2] cgroups: read-write lock CLONE_THREAD forking per threadgroup Ben Blum
2010-05-30 1:31 ` Ben Blum
2010-05-30 1:33 ` [RFC] [PATCH 2/2] cgroups: make procs file writable Ben Blum
2010-05-30 1:33 ` Ben Blum
[not found] ` <20100530013303.GC762-kwnxxEB+oiWqwBT9kiuFm8WGCVk0P7UB@public.gmane.org>
2010-05-31 17:52 ` Oleg Nesterov
2010-05-31 17:52 ` Oleg Nesterov
2010-05-31 18:04 ` Oleg Nesterov
[not found] ` <20100531180446.GA16249-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-06-01 18:57 ` Paul Menage
2010-06-01 18:57 ` Paul Menage
[not found] ` <AANLkTimcrX0TjzDMNJdubR92pAO4IPATbVpyvvVt0qIV-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-06-02 14:06 ` Oleg Nesterov
2010-06-02 14:06 ` Oleg Nesterov
[not found] ` <20100602140659.GA5324-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-06-02 19:53 ` Paul Menage
2010-06-02 19:53 ` Paul Menage
[not found] ` <AANLkTin-T6ij3xf0ceGoCamwcoayxyf0GdAKY6yXDMVl-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-06-02 20:20 ` Oleg Nesterov
2010-06-02 20:20 ` Oleg Nesterov
[not found] ` <20100602202048.GB28663-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-06-02 20:31 ` Paul Menage
2010-06-02 20:31 ` Paul Menage
[not found] ` <AANLkTimrJFiidM8BlUNvmzfapUAv8369R9PYnTscasEf-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-06-02 20:58 ` Oleg Nesterov
2010-06-02 20:58 ` Oleg Nesterov
2010-06-02 21:12 ` Paul Menage
2010-06-02 21:38 ` Oleg Nesterov
[not found] ` <20100602213832.GB31949-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-06-02 22:03 ` Paul Menage
2010-06-02 22:03 ` Paul Menage
[not found] ` <AANLkTimsusetA9B95-LvKsDdAB_PegYH7Zljyi4Doe_q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-06-03 4:44 ` Ben Blum
2010-06-03 4:44 ` Ben Blum
[not found] ` <AANLkTimfHlapl7mbRyAazWW5q5Wzs23n6i9wIhVtSv6r-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-06-02 21:38 ` Oleg Nesterov
[not found] ` <20100602205855.GA30039-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-06-02 21:12 ` Paul Menage
2010-06-03 4:40 ` Ben Blum
2010-06-03 4:40 ` Ben Blum
2010-06-03 14:48 ` Oleg Nesterov [this message]
[not found] ` <20100603044001.GA21006-jeg9jHBoDvuqwBT9kiuFm8WGCVk0P7UB@public.gmane.org>
2010-06-03 14:48 ` Oleg Nesterov
2010-06-03 4:56 ` Ben Blum
[not found] ` <20100603045629.GC21006-jeg9jHBoDvuqwBT9kiuFm8WGCVk0P7UB@public.gmane.org>
2010-06-03 14:43 ` Oleg Nesterov
2010-06-03 14:43 ` Oleg Nesterov
[not found] ` <20100531175242.GA14691-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2010-05-31 18:04 ` Oleg Nesterov
2010-06-03 4:56 ` Ben Blum
-- strict thread matches above, loose matches on Subject: below --
2009-08-20 21:14 + cgroups-add-functionality-to-read-write-lock-clone_thread-forking-per-threadgroup.patch added to -mm tree akpm
2009-08-21 10:26 ` + cgroups-add-functionality-to-read-write-lock-clone_thread-forking-pe r-threadgroup.patch " Oleg Nesterov
2009-08-21 10:45 ` Oleg Nesterov
2009-08-21 23:37 ` Paul Menage
2009-08-22 13:09 ` Oleg Nesterov
2010-01-03 19:06 ` Ben Blum
[not found] ` <20100103190613.GA13423-OM76b2Iv3yLQjUSlxSEPGw@public.gmane.org>
2010-01-03 19:09 ` [RFC] [PATCH 2/2] cgroups: make procs file writable Ben Blum
2010-01-03 19:09 ` Ben Blum
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=20100603144810.GB6284@redhat.com \
--to=oleg@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=bblum@andrew.cmu.edu \
--cc=containers@lists.linux-foundation.org \
--cc=ebiederm@xmission.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lizf@cn.fujitsu.com \
--cc=matthltc@us.ibm.com \
--cc=menage@google.com \
/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.