From: Jerome Marchand <jmarchan@redhat.com>
To: Jiang Liu <liuj97@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Nitin Gupta <ngupta@vflare.org>, Minchan Kim <minchan@kernel.org>,
Jiang Liu <jiang.liu@huawei.com>,
devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v3 02/10] zram: use zram->lock to protect zram_free_page() in swap free notify path
Date: Fri, 07 Jun 2013 11:32:21 +0200 [thread overview]
Message-ID: <51B1A8A5.8050904@redhat.com> (raw)
In-Reply-To: <1370534851-26056-3-git-send-email-jiang.liu@huawei.com>
On 06/06/2013 06:07 PM, Jiang Liu wrote:
> zram_slot_free_notify() is free-running without any protection from
> concurrent operations. So there are race conditions between
> zram_bvec_read()/zram_bvec_write() and zram_slot_free_notify(),
> and possible consequences include:
> 1) Trigger BUG_ON(!handle) on zram_bvec_write() side.
> 2) Access to freed pages on zram_bvec_read() side.
> 3) Break some fields (bad_compress, good_compress, pages_stored)
> in zram->stats if the swap layer makes concurrently call to
> zram_slot_free_notify().
>
> So enhance zram_slot_free_notify() to acquire writer lock on zram->lock
> before calling zram_free_page().
>
> Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
> Cc: stable@vger.kernel.org
Acked-by: Jerome Marchand <jmarchand@redhat.com>
next prev parent reply other threads:[~2013-06-07 9:32 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1370534851-26056-1-git-send-email-jiang.liu@huawei.com>
2013-06-06 16:07 ` [PATCH v3 01/10] zram: avoid invalid memory access in zram_exit() Jiang Liu
2013-06-07 7:58 ` Minchan Kim
2013-06-07 9:29 ` Jerome Marchand
2013-06-06 16:07 ` [PATCH v3 02/10] zram: use zram->lock to protect zram_free_page() in swap free notify path Jiang Liu
2013-06-07 8:05 ` Minchan Kim
2013-06-07 9:32 ` Jerome Marchand [this message]
2013-06-06 16:07 ` [PATCH v3 03/10] zram: destroy all devices on error recovery path in zram_init() Jiang Liu
2013-06-06 16:07 ` [PATCH v3 04/10] zram: avoid double free in function zram_bvec_write() Jiang Liu
2013-06-07 8:06 ` Minchan Kim
2013-06-06 16:07 ` [PATCH v3 05/10] zram: avoid access beyond the zram device Jiang Liu
2013-06-07 8:09 ` Minchan Kim
2013-06-07 9:40 ` Jerome Marchand
2013-06-07 9:43 ` Jiang Liu
2013-06-06 16:07 ` [PATCH v3 06/10] zram: protect sysfs handler from invalid memory access Jiang Liu
2013-06-07 9:41 ` Jerome Marchand
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