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From: Peter Zijlstra <peterz@infradead.org>
To: Kees Cook <keescook@chromium.org>
Cc: Zefan Li <lizefan@huawei.com>,
	Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Ingo Molnar <mingo@redhat.com>, Tejun Heo <tj@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	cgroups@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	fernando_b1@lab.ntt.co.jp
Subject: Re: Racy manipulation of task_struct->flags in cgroups code causes hard to reproduce kernel panics
Date: Sat, 20 Sep 2014 20:04:18 +0200	[thread overview]
Message-ID: <20140920180418.GR2832@worktop.localdomain> (raw)
In-Reply-To: <CAGXu5j+P_kcgZuqYsemgL0KU_zRhz5HGJ6seh2oLyyst=cZP6g@mail.gmail.com>

On Sat, Sep 20, 2014 at 10:15:50AM -0700, Kees Cook wrote:
> On Sat, Sep 20, 2014 at 7:30 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Sat, Sep 20, 2014 at 01:55:54PM +0800, Zefan Li wrote:
> >> We should make the updating of this flag atomic.
> >
> >>  /* Per-process atomic flags. */
> >>  #define PFA_NO_NEW_PRIVS 0x00000001  /* May not gain new privileges. */
> >> +#define PFA_SPREAD_PAGE  0x00000002  /* Spread page cache over cpuset */
> >> +#define PFA_SPREAD_SLAB  0x00000004  /* Spread some slab caches over cpuset */
> >
> > Ooh, I was not ware we had those.. /me checks where that came from. Hmm
> > weird, while I did get that patch it had a seccomp prefix when landing
> > in my inbox so I ignored it. However the commit has a sched prefix
> > (which I would not have ignored). Dubious things happened here.
> 
> The series went through a lot of revisions, so it probably gained the
> sched prefix later in its life. Is there anything that needs changing
> about how this has been implemented?

No, don't think so, just got surprised.

  reply	other threads:[~2014-09-20 18:04 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-19 11:53 Tetsuo Handa
2014-09-19 22:21 ` Peter Zijlstra
2014-09-20  5:55 ` Zefan Li
2014-09-20 10:40   ` [PATCH 3.17-rc5] Fix confusing PFA_NO_NEW_PRIVS constant Tetsuo Handa
2014-09-20 17:19     ` Kees Cook
2014-09-20 14:30   ` Racy manipulation of task_struct->flags in cgroups code causes hard to reproduce kernel panics Peter Zijlstra
2014-09-20 17:15     ` Kees Cook
2014-09-20 18:04       ` Peter Zijlstra [this message]
2014-09-20 17:28   ` Tejun Heo
2014-09-21  5:15     ` Tetsuo Handa
2014-09-22  2:15       ` Zefan Li

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