linux-kernel - Re: [PATCH 2.6.28-rc6] block: internal dequeue shouldn't start timer

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]

Date:	Mon, 1 Dec 2008 15:45:29 -0800
From:	Mike Anderson <andmike@...ux.vnet.ibm.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	Jens Axboe <jens.axboe@...cle.com>,
	James Bottomley <James.Bottomley@...senPartnership.com>,
	linux-scsi <linux-scsi@...r.kernel.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Hannes Reinecke <hare@...e.de>
Subject: Re: [PATCH 2.6.28-rc6] block: internal dequeue shouldn't start
	timer

Tejun Heo <tj@...nel.org> wrote:
> blkdev_dequeue_request() and elv_dequeue_request() are equivalent and
> both start the timeout timer.  Barrier code dequeues the original
> barrier request but doesn't passes the request itself to lower level
> driver, only broken down proxy requests; however, as the original
> barrier code goes through the same dequeue path and timeout timer is
> started on it.  If barrier sequence takes long enough, this timer
> expires but the low level driver has no idea about this request and
> oops follows.
> 
> Timeout timer shouldn't have been started on the original barrier
> request as it never goes through actual IO.  This patch unexports
> elv_dequeue_request(), which has no external user anyway, and makes it
> operate on elevator proper w/o adding the timer and make
> blkdev_dequeue_request() call elv_dequeue_request() and add timer.
> Internal users which don't pass the request to driver - barrier code
> and end_that_request_last() - are converted to use
> elv_dequeue_request().
> 
> Signed-off-by: Tejun Heo <tj@...nel.org>
> Cc: Mike Anderson <andmike@...ux.vnet.ibm.com>
> ---
> Mike, this should fix the problem you were seeing (blk_add_timer on
> requests w/o REQ_STARTED set).
> 

Yes this fixed the "w/o REQ_STARTED" error I was seeing on a distro kernel
and a mainline system. 

Thanks,

-andmike
--
Michael Anderson
andmike@...ux.vnet.ibm.com
--
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/