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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, bugme-daemon@bugzilla.kernel.org,
	greenhostnl@gmail.com, Tejun Heo <tj@kernel.org>
Subject: Re: [Bugme-new] [Bug 39632] New: kernel BUG at arch/x86/mm/fault.c:395
Date: Thu, 28 Jul 2011 09:23:33 +0900	[thread overview]
Message-ID: <20110728092333.9ba574d6.kamezawa.hiroyu@jp.fujitsu.com> (raw)
In-Reply-To: <20110727170148.0172a03c.akpm@linux-foundation.org>

On Wed, 27 Jul 2011 17:01:48 -0700
Andrew Morton <akpm@linux-foundation.org> wrote:

> 
> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
> 
> On Wed, 20 Jul 2011 15:25:32 GMT
> bugzilla-daemon@bugzilla.kernel.org wrote:
> 
> > https://bugzilla.kernel.org/show_bug.cgi?id=39632
> > 
> >            Summary: kernel BUG at arch/x86/mm/fault.c:395
> >            Product: Memory Management
> >            Version: 2.5
> >     Kernel Version: 3.0.0-RC7
> >           Platform: All
> >         OS/Version: Linux
> >               Tree: Mainline
> >             Status: NEW
> >           Severity: normal
> >           Priority: P1
> >          Component: Other
> >         AssignedTo: akpm@linux-foundation.org
> >         ReportedBy: greenhostnl@gmail.com
> >         Regression: No
> 
> I think this is a plain old oops in mem_cgroup_charge_statistics(), but
> for some reason it's treating the oopsing address as part of the
> vmalloc arena.  Perhaps this is what a use-after-free looks like on the
> new percpu area implementation?
> 

> [426900.218491]  [<ffffffff81358bd9>] ? do_page_fault+0x339/0x4e0
> [426900.218501]  [<ffffffff810b0d64>] ? __alloc_pages_nodemask+0x144/0x860
> [426900.218510]  [<ffffffff81355915>] ? page_fault+0x25/0x30
> [426900.218519]  [<ffffffff810df69a>] ? mem_cgroup_charge_statistics+0x3a/0x60

Hmm, touches unmapped vmalloc area and caused OOps.

And yes, mem_cgroup_charge_statistics() touches per-cpu area, which is allocated
in vmalloc() area....

The percpu area is allocated at a cgroup creation and freed at destroy.

I wonder why oom-kill is a trigger for the issue...if there is 
double-free or some other issue, other trouble can be seen...

Thanks,
-Kame









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  reply	other threads:[~2011-07-28  0:30 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-39632-10286@https.bugzilla.kernel.org/>
2011-07-28  0:01 ` Andrew Morton
2011-07-28  0:23   ` KAMEZAWA Hiroyuki [this message]
2011-07-28  3:03     ` KAMEZAWA Hiroyuki

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