From: Fengguang Wu <fengguang.wu@intel.com>
To: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>, Vivek Goyal <vgoyal@redhat.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH block/for-3.4/core] cfq: fix cfqg ref handling when BLK_CGROUP && !CFQ_GROUP_IOSCHED
Date: Fri, 16 Mar 2012 12:20:36 +0800 [thread overview]
Message-ID: <20120316042036.GA32728@localhost> (raw)
In-Reply-To: <20120315163546.GA32137@google.com>
On Thu, Mar 15, 2012 at 09:35:46AM -0700, Tejun Heo wrote:
> When BLK_CGROUP is enabled but CFQ_GROUP_IOSCHED is, cfq ends up
> calling blkg_get/put() on dummy cfqg leading to the following crash.
>
> BUG: unable to handle kernel NULL pointer dereference at 00000000000000b0
> IP: [<ffffffff813d44d8>] cfq_init_queue+0x258/0x430
> Reported-by: Fengguang Wu <fengguang.wu@intel.com>
> Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Fengguang Wu <fengguang.wu@intel.com>
Thanks for the quick fix!
> ---
> Yeap, forgot to test that config combination. Fengguang, can you
> please test this patch? Jens, once Fengguang confirms the fix, can
> you please apply this on top of for-3.4/core along with the pending
> stats updates?
next prev parent reply other threads:[~2012-03-16 4:21 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-15 9:49 NULL dereference BUG in cfq_init_queue() Fengguang Wu
2012-03-15 16:35 ` [PATCH block/for-3.4/core] cfq: fix cfqg ref handling when BLK_CGROUP && !CFQ_GROUP_IOSCHED Tejun Heo
2012-03-15 16:46 ` Vivek Goyal
2012-03-15 16:50 ` Tejun Heo
2012-03-15 17:01 ` Vivek Goyal
2012-03-15 17:18 ` Tejun Heo
2012-03-16 4:20 ` Fengguang Wu [this message]
2012-03-23 13:04 ` Jens Axboe
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