From: Pekka Enberg <penberg@kernel.org>
To: Christoph Lameter <cl@linux.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Christian Kujau <lists@nerdbynature.de>,
markus@trippelsdorf.de, David Rientjes <rientjes@google.com>
Subject: Re: [PATCH V2] slub: avoid potential NULL dereference or corruption
Date: Wed, 23 Nov 2011 23:19:51 +0200 [thread overview]
Message-ID: <1322083191.1428.125.camel@jaguar> (raw)
In-Reply-To: <alpine.DEB.2.00.1111230916220.16139@router.home>
On Wed, 2011-11-23 at 09:17 -0600, Christoph Lameter wrote:
> On Wed, 23 Nov 2011, Pekka Enberg wrote:
>
> > On Tue, 22 Nov 2011, Eric Dumazet wrote:
> > > show_slab_objects() can trigger NULL dereferences or memory corruption.
> > >
> > > Another cpu can change its c->page to NULL or c->node to NUMA_NO_NODE
> > > while we use them.
> > >
> > > Use ACCESS_ONCE(c->page) and ACCESS_ONCE(c->node) to make sure this
> > > cannot happen.
> > >
> > > Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
> >
> > Did someone test this patch? Does it fix any of the reported issues?
>
> It does not fix any current issues but it is safe against potential
> compiler refetching of variables that we have already checked against
> bad values.
>
> I thought I acked it already?
Yes, you did. I'm just trying to figure out which ones are going
straight to Linus and which ones can wait for v3.3.
Pekka
next prev parent reply other threads:[~2011-11-23 21:19 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-22 14:53 [PATCH] " Eric Dumazet
2011-11-22 14:57 ` Christoph Lameter
2011-11-22 15:02 ` [PATCH V2] " Eric Dumazet
2011-11-22 15:03 ` Christoph Lameter
2011-11-23 5:30 ` David Rientjes
2011-11-23 8:32 ` Pekka Enberg
2011-11-23 15:17 ` Christoph Lameter
2011-11-23 21:19 ` Pekka Enberg [this message]
2011-11-23 22:29 ` David Rientjes
2011-11-24 6:45 ` Pekka Enberg
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