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From: "Paul Menage" <menage@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>,
	linux-mm@kvack.org, skumar@linux.vnet.ibm.com,
	yamamoto@valinux.co.jp, lizf@cn.fujitsu.com,
	linux-kernel@vger.kernel.org, nishimura@mxp.nes.nec.co.jp,
	xemul@openvz.org, hugh@veritas.com,
	kamezawa.hiroyu@jp.fujitsu.com
Subject: Re: [-mm][PATCH 1/2] mm owner fix race between swap and exit
Date: Mon, 11 Aug 2008 17:43:37 -0700	[thread overview]
Message-ID: <6599ad830808111743l58322a46u84f7af3e21467b0b@mail.gmail.com> (raw)
In-Reply-To: <20080811173138.71f5bbe4.akpm@linux-foundation.org>

On Mon, Aug 11, 2008 at 5:31 PM, Andrew Morton
<akpm@linux-foundation.org> wrote:
>> The fix is to notify the subsystem (via mm_owner_changed callback), if
>> no new owner is found by specifying the new task as NULL.
>
> This patch applies to mainline, 2.6.27-rc2 and even 2.6.26.
>
> Against which kernel/patch is it actually applicable?
>
> (If the answer was "all of the above" then please don't go embedding
> mainline bugfixes in the middle of a -mm-only patch series!)

The main thing this fixes is the memrlimit controller, which is only
in -mm. But there's also a dereference of mm->owner in memcontrol.c -
and I think that needs to be fixed to handle a possible NULL mm->owner
too, since in the case of a swapoff racing with the last user of an mm
exiting, I suspect that the swapoff code could try to pull in a page
that gets charged to the mm after its owner has been set to NULL.

Paul

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  reply	other threads:[~2008-08-12  0:43 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-11 10:07 [-mm][PATCH 0/2] Memory rlimit fix crash on fork Balbir Singh
2008-08-11 10:07 ` [-mm][PATCH 1/2] mm owner fix race between swap and exit Balbir Singh
2008-08-12  0:31   ` Andrew Morton
2008-08-12  0:43     ` Paul Menage [this message]
2008-08-12  4:06     ` Balbir Singh
2008-08-12  4:56       ` Andrew Morton
2008-08-12  5:04         ` Balbir Singh
2008-08-11 10:07 ` [-mm][PATCH 2/2] Memory rlimit enhance mm_owner_changed callback to deal with exited owner Balbir Singh
2008-08-12  0:39   ` Paul Menage
2008-08-13  0:14 ` [-mm][PATCH 0/2] Memory rlimit fix crash on fork Andrew Morton
2008-08-13  1:24   ` Balbir Singh
2008-08-13  2:07     ` Balbir Singh

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