From: Jens Axboe <jaxboe@fusionio.com>
To: Tejun Heo <tj@kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"kay.sievers@vrfy.org" <kay.sievers@vrfy.org>,
"hch@infradead.org" <hch@infradead.org>
Subject: Re: block: Fix oops caused by __blkdev_get() calling disk_unblock_events() with invalid @disk
Date: Wed, 9 Mar 2011 19:26:44 +0100 [thread overview]
Message-ID: <4D77C664.3080803@fusionio.com> (raw)
In-Reply-To: <20110309153859.GD27010@htj.dyndns.org>
On 2011-03-09 16:38, Tejun Heo wrote:
> Commit 57c966b8b2 (block: Don't check events while open is in
> progress) made __blkdev_get() block events around open calls; however,
> it used invalid @disk pointer in the following cases.
>
> * When ->open() returns -ERESTARTSYS, disk_unblock_events() is called
> after @disk is put. @disk may be invalid by the time unblock is
> called.
>
> This is fixed by moving references after disk_unblock_events().
>
> * When there are multiple openers, @disk is cleared to %NULL and later
> disk_unblock_disk() is called with %NULL @disk causing oops.
>
> This is fixed by moving reference putting after open success is
> determined and not clearing @disk to %NULL. On success, @disk is
> valid because there is another opener holding reference to it. On
> failure, the references are put after disk_unblock_events() is
> called.
Thanks, applied. A bit unfortunate to have a 100% crasher in the tree,
though. Will suck for bisects.
--
Jens Axboe
next prev parent reply other threads:[~2011-03-09 18:26 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-09 9:13 [PATCHSET] block: Convert block drivers to ->check_events(), take#2 Tejun Heo
2011-03-09 9:13 ` [PATCH 01/16] block: Don't implicitly trigger event check on disk_unblock_events() Tejun Heo
2011-03-09 9:13 ` [PATCH 02/16] block: Don't check events on close unless it was blocked Tejun Heo
2011-03-09 9:13 ` [PATCH 03/16] block: Don't check events while open is in progress Tejun Heo
2011-03-09 9:13 ` [PATCH 04/16] ide: Convert to bdops->check_events() Tejun Heo
2011-03-09 22:17 ` David Miller
2011-03-09 9:13 ` [PATCH 05/16] floppy,{ami|ata}flop: " Tejun Heo
2011-03-09 9:13 ` [PATCH 06/16] gdrom,viocd: " Tejun Heo
2011-03-09 9:13 ` [PATCH 07/16] paride: " Tejun Heo
2011-03-09 9:13 ` [PATCH 08/16] dac960: " Tejun Heo
2011-03-09 9:13 ` [PATCH 09/16] swim[3]: " Tejun Heo
2011-03-10 0:10 ` Benjamin Herrenschmidt
2011-03-09 9:13 ` [PATCH 10/16] ub: " Tejun Heo
2011-03-09 16:46 ` Pete Zaitcev
2011-03-09 16:58 ` Tejun Heo
2011-03-09 9:13 ` [PATCH 11/16] xsysace: " Tejun Heo
2011-03-09 9:13 ` [PATCH 12/16] i2o_block: " Tejun Heo
2011-03-09 9:13 ` [PATCH 13/16] s390/tape_block: " Tejun Heo
2011-03-09 9:13 ` [PATCH 14/16] umem: Drop dummy ->media_changed() Tejun Heo
2011-03-09 9:13 ` [PATCH 15/16] pktcdvd: Convert to bdops->check_events() Tejun Heo
2011-03-09 9:13 ` [PATCH 16/16] staging: " Tejun Heo
2011-03-09 9:20 ` [PATCHSET] block: Convert block drivers to ->check_events(), take#2 Jens Axboe
2011-03-09 14:49 ` Jens Axboe
2011-03-09 15:38 ` block: Fix oops caused by __blkdev_get() calling disk_unblock_events() with invalid @disk Tejun Heo
2011-03-09 18:26 ` Jens Axboe [this message]
2011-03-09 18:59 ` Tejun Heo
2011-03-09 19:16 ` Jens Axboe
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