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From: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>,
	jbottomley@parallels.com, linux-scsi@vger.kernel.org,
	Huajun Li <huajun.li.lee@gmail.com>,
	Axel Theilmann <theilmann@pre-sense.de>,
	linux-kernel@vger.kernel.org
Subject: Re: Yet another hot unplug NULL pointer dereference (was Re: status of oops in sd_revalidate_disk?)
Date: Thu, 16 Feb 2012 10:04:03 +0900	[thread overview]
Message-ID: <4F3C5603.1040108@ce.jp.nec.com> (raw)
In-Reply-To: <CAO+b5-rNF1R5NcSdVSsKLML4wyZBBGv-zUdq+B1y0kfHxLpupA@mail.gmail.com>

Hi,

On 02/15/12 20:29, Bart Van Assche wrote:
> On Wed, Feb 15, 2012 at 3:26 AM, Jun'ichi Nomura <j-nomura@ce.jp.nec.com> wrote:
>> I think this patch is good, too.
>> Since QUEUE_FLAG_DEAD is also racy, it is not much different
>> from queuedata check, IMO.
> 
> Are you sure ? As far as I know the block layer takes care of
> synchronizing queue flag modifications against request_fn invocations.

QUEUE_FLAG_DEAD is set outside of queue_lock. So it's racy.
However, it's single directional change and the race is benign
if the driver, who sets QUEUE_FLAG_DEAD, is ready to reject
requests.
q->queuedata is same with that regard.

-- 
Jun'ichi Nomura, NEC Corporation

  reply	other threads:[~2012-02-16  1:05 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <4EE8E419.8010000@pre-sense.de>
     [not found] ` <CA+v9cxZFUC45WD0=+8mvH2Tq_xvX3PgaW4ttzPep0jqvqab_6w@mail.gmail.com>
2011-12-25 20:58   ` Yet another hot unplug NULL pointer dereference (was Re: status of oops in sd_revalidate_disk?) Stefan Richter
2011-12-27 10:21     ` Axel Theilmann
2011-12-27 13:40       ` Stefan Richter
2012-02-14 11:34     ` Jun'ichi Nomura
2012-02-14 11:54       ` Bart Van Assche
2012-02-14 13:38         ` Stefan Richter
2012-02-14 19:11           ` Bart Van Assche
2012-02-15  2:26             ` Jun'ichi Nomura
2012-02-15 11:29               ` Bart Van Assche
2012-02-16  1:04                 ` Jun'ichi Nomura [this message]
2012-03-13 18:10       ` Bart Van Assche
2012-03-16  8:58         ` Jun'ichi Nomura
2012-03-16 18:53           ` Bart Van Assche

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