From: Tejun Heo <tj@kernel.org>
To: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Vivek Goyal <vgoyal@redhat.com>, Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH] blkcg: Fix use-after-free of q->root_blkg and q->root_rl.blkg
Date: Thu, 18 Oct 2012 14:21:33 -0700 [thread overview]
Message-ID: <20121018212133.GL13370@google.com> (raw)
In-Reply-To: <507E7030.9070607@ce.jp.nec.com>
On Wed, Oct 17, 2012 at 05:45:36PM +0900, Jun'ichi Nomura wrote:
> blk_put_rl() does not call blkg_put() for q->root_rl because we
> don't take request list reference on q->root_blkg.
> However, if root_blkg is once attached then detached (freed),
> blk_put_rl() is confused by the bogus pointer in q->root_blkg.
>
> For example, with !CONFIG_BLK_DEV_THROTTLING &&
> CONFIG_CFQ_GROUP_IOSCHED,
> switching IO scheduler from cfq to deadline will cause system stall
> after the following warning with 3.6:
...
> This patch clears q->root_blkg and q->root_rl.blkg when root blkg
> is destroyed.
>
> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
> Acked-by: Vivek Goyal <vgoyal@redhat.com>
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Jens Axboe <axboe@kernel.dk>
Acked-by: Tejun Heo <tj@kernel.org>
Jens, this one needs Cc: stable.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-10-18 21:21 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-10 5:11 [PATCH] Fix use-after-free of q->root_blkg and q->root_rl.blkg Jun'ichi Nomura
2012-10-10 15:59 ` Vivek Goyal
2012-10-11 1:31 ` Jun'ichi Nomura
2012-10-11 18:55 ` Vivek Goyal
2012-10-16 23:20 ` Tejun Heo
2012-10-17 0:02 ` Jun'ichi Nomura
2012-10-17 8:45 ` [PATCH] blkcg: " Jun'ichi Nomura
2012-10-18 21:21 ` Tejun Heo [this message]
2012-10-22 18:43 ` Jens Axboe
2012-10-17 13:47 ` [PATCH] " Vivek Goyal
2012-10-18 2:56 ` Jun'ichi Nomura
2012-10-18 13:31 ` Vivek Goyal
2012-10-18 21:20 ` Tejun Heo
2012-10-19 14:53 ` Vivek Goyal
2012-10-22 0:55 ` Jun'ichi Nomura
2012-10-22 1:15 ` [PATCH] blkcg: stop iteration early if root_rl is the only request list Jun'ichi Nomura
2012-10-22 15:31 ` Vivek Goyal
2012-10-22 18:43 ` Jens Axboe
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