linux-kernel - Re: [BUGFIX][PATCH v4] memcg: fix memory migration of shmem swapcache

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]

Message-ID: <20110108092613.GF4654@cmpxchg.org>
Date:	Sat, 8 Jan 2011 10:26:13 +0100
From:	Johannes Weiner <hannes@...xchg.org>
To:	Daisuke Nishimura <nishimura@....nes.nec.co.jp>
Cc:	balbir@...ux.vnet.ibm.com, Minchan Kim <minchan.kim@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-mm <linux-mm@...ck.org>
Subject: Re: [BUGFIX][PATCH v4] memcg: fix memory migration of shmem swapcache

On Thu, Jan 06, 2011 at 03:29:11PM +0900, Daisuke Nishimura wrote:
> In current implimentation, mem_cgroup_end_migration() decides whether the page
> migration has succeeded or not by checking "oldpage->mapping".
> 
> But if we are tring to migrate a shmem swapcache, the page->mapping of it is
> NULL from the begining, so the check would be invalid.
> As a result, mem_cgroup_end_migration() assumes the migration has succeeded
> even if it's not, so "newpage" would be freed while it's not uncharged.
> 
> This patch fixes it by passing mem_cgroup_end_migration() the result of the
> page migration.
> 
> Signed-off-by: Daisuke Nishimura <nishimura@....nes.nec.co.jp>
> Reviewed-by: Minchan Kim <minchan.kim@...il.com>
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>

Reviewed-by: Johannes Weiner <hannes@...xchg.org>
--
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/