linux-kernel - Re: [PATCH 3/5] track the root (oldest) anon

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 12 May 2010 17:01:38 -0400
From:	Rik van Riel <riel@...hat.com>
To:	Mel Gorman <mel@....ul.ie>
CC:	Andrew Morton <akpm@...ux-foundation.org>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Minchan Kim <minchan.kim@...il.com>,
	Linux-MM <linux-mm@...ck.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: Re: [PATCH 3/5] track the root (oldest) anon_vma

On 05/12/2010 04:59 PM, Mel Gorman wrote:
> On Wed, May 12, 2010 at 01:39:58PM -0400, Rik van Riel wrote:
>> Subject: track the root (oldest) anon_vma
>>
>> Track the root (oldest) anon_vma in each anon_vma tree.   Because we only
>> take the lock on the root anon_vma, we cannot use the lock on higher-up
>> anon_vmas to lock anything.  This makes it impossible to do an indirect
>> lookup of the root anon_vma, since the data structures could go away from
>> under us.
>>
>> However, a direct pointer is safe because the root anon_vma is always the
>> last one that gets freed on munmap or exit, by virtue of the same_vma list
>> order and unlink_anon_vmas walking the list forward.
>>
>
> Shouldn't this be "usually the last one that gets freed" because of the
> ref-counting by KSM aspect? Minor nit anyway.

It needs to be the last one that gets freed.  Patch 5/5 makes
sure that it is when KSM refcounting is involved.

>> Signed-off-by: Rik van Riel<riel@...hat.com>
>
> Otherwise
>
> Acked-by: Mel Gorman<mel@....ul.ie>

Thank you for reviewing these patches.

-- 
All rights reversed
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/