From: Andi Kleen <andi@firstfloor.org>
To: kosaki.motohiro@gmail.com
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Andrew Morton <akpm@google.com>, Dave Jones <davej@redhat.com>,
Mel Gorman <mgorman@suse.de>,
Linus Torvalds <torvalds@linux-foundation.org>,
Christoph Lameter <cl@linux.com>,
stable@vger.kernel.org, hughd@google.com,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Andrew Morton <akpm@linux-foundation.org>,
Miao Xie <miaox@cn.fujitsu.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 5/6] mempolicy: fix a memory corruption by refcount imbalance in alloc_pages_vma()
Date: Wed, 30 May 2012 13:37:03 -0700 [thread overview]
Message-ID: <m2r4u1jths.fsf@firstfloor.org> (raw)
In-Reply-To: <1338368529-21784-6-git-send-email-kosaki.motohiro@gmail.com> (kosaki motohiro's message of "Wed, 30 May 2012 05:02:08 -0400")
kosaki.motohiro@gmail.com writes:
> From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
>
> commit cc9a6c8776 (cpuset: mm: reduce large amounts of memory barrier related
> damage v3) introduced a memory corruption.
>
> shmem_alloc_page() passes pseudo vma and it has one significant unique
> combination, vma->vm_ops=NULL and (vma->policy->flags & MPOL_F_SHARED).
>
> Now, get_vma_policy() does NOT increase a policy ref when vma->vm_ops=NULL
> and mpol_cond_put() DOES decrease a policy ref when a policy has MPOL_F_SHARED.
> Therefore, when cpuset race is happen and alloc_pages_vma() fall in
> 'goto retry_cpuset' path, a policy refcount will be decreased too much and
> therefore it will make memory corruption.
>
> This patch fixes it.
Looks good.
Acked-by: Andi Kleen <ak@linux.intel.com>
-Andi
--
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next prev parent reply other threads:[~2012-05-30 20:37 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-30 9:02 [PATCH 0/6] mempolicy memory corruption fixlet kosaki.motohiro
2012-05-30 9:02 ` [PATCH 1/6] Revert "mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages" kosaki.motohiro
2012-05-30 19:17 ` Christoph Lameter
2012-05-30 19:39 ` KOSAKI Motohiro
2012-05-30 19:44 ` Christoph Lameter
2012-05-31 6:49 ` KOSAKI Motohiro
2012-05-30 9:02 ` [PATCH 2/6] mempolicy: Kill all mempolicy sharing kosaki.motohiro
2012-05-30 19:41 ` Christoph Lameter
2012-05-30 19:46 ` KOSAKI Motohiro
2012-05-30 19:48 ` Andi Kleen
2012-05-30 20:31 ` Andi Kleen
2012-05-30 20:58 ` KOSAKI Motohiro
2012-05-30 9:02 ` [PATCH 3/6] mempolicy: fix a race in shared_policy_replace() kosaki.motohiro
2012-05-30 9:02 ` [PATCH 4/6] mempolicy: fix refcount leak in mpol_set_shared_policy() kosaki.motohiro
2012-05-30 9:02 ` [PATCH 5/6] mempolicy: fix a memory corruption by refcount imbalance in alloc_pages_vma() kosaki.motohiro
2012-05-30 20:37 ` Andi Kleen [this message]
2012-05-30 9:02 ` [PATCH 6/6] MAINTAINERS: Added MEMPOLICY entry kosaki.motohiro
2012-05-30 19:27 ` Christoph Lameter
2012-05-30 18:26 ` [PATCH 0/6] mempolicy memory corruption fixlet Linus Torvalds
2012-05-30 18:34 ` Christoph Lameter
2012-05-30 18:46 ` Andi Kleen
2012-05-30 18:50 ` Christoph Lameter
2012-05-30 19:32 ` Andi Kleen
2012-05-30 19:42 ` Christoph Lameter
2012-05-30 19:52 ` Andi Kleen
2012-05-30 20:00 ` KOSAKI Motohiro
2012-05-30 21:22 ` Ben Hutchings
2012-05-30 21:25 ` KOSAKI Motohiro
2012-05-30 19:54 ` KOSAKI Motohiro
2012-05-30 20:10 ` Andi Kleen
2012-05-30 20:16 ` KOSAKI Motohiro
2012-06-01 0:45 ` david
2012-06-01 13:51 ` Christoph Lameter
2012-06-01 19:31 ` david
2012-06-01 19:37 ` KOSAKI Motohiro
2012-06-05 19:02 ` Linus Torvalds
2012-06-05 19:17 ` Andrew Morton
2012-06-06 19:10 ` KOSAKI Motohiro
2012-05-30 19:03 ` Linus Torvalds
2012-05-30 20:10 ` KOSAKI Motohiro
-- strict thread matches above, loose matches on Subject: below --
2012-06-11 9:17 [PATCH 0/6][resend] " kosaki.motohiro
2012-06-11 9:17 ` [PATCH 5/6] mempolicy: fix a memory corruption by refcount imbalance in alloc_pages_vma() kosaki.motohiro
2012-06-11 13:33 ` Ben Hutchings
2012-06-11 15:24 ` KOSAKI Motohiro
2012-06-12 14:20 ` Mel Gorman
2012-06-12 16:31 ` KOSAKI Motohiro
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