From: Zhou Yingchao <yingchao.zhou@gmail.com>
To: Richard Hayden <rahaydenuk@yahoo.co.uk>
Cc: linux-kernel@vger.kernel.org
Subject: Re: A couple of OOM killer races
Date: Fri, 2 Sep 2005 09:29:25 +0800 [thread overview]
Message-ID: <67029b17050901182964c80289@mail.gmail.com> (raw)
In-Reply-To: <43176820.5060609@yahoo.co.uk>
On 9/2/05, Richard Hayden <rahaydenuk@yahoo.co.uk> wrote:
> Hi all,
>
> It appears there is no protection in badness() (called by
> out_of_memory() for each process) when it reads p->mm->total_vm. Another
> processor (or a kernel preemption) could presumably run do_exit and then
> exit_mm, freeing the process in question's reference to its mm just
> after the (!p->mm) check but before it reads p->mm->total_vm, making the
> latter reference a null pointer reference.
In badness, the tasklist_lock has been hold. And when an exit signal
delived to it because other thread call do_group_exit, it need to hold
the tasklist_lock first, so we are protected.
--
Yingchao Zhou
next prev parent reply other threads:[~2005-09-02 1:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-01 20:44 A couple of OOM killer races Richard Hayden
2005-09-02 1:29 ` Zhou Yingchao [this message]
2005-09-08 2:09 ` Coywolf Qi Hunt
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