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From: Johannes Thumshirn <jthumshirn@suse.de>
To: Jan Kara <jack@suse.cz>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
	Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org
Subject: Re: [PATCH 0/15 v2] loop: Fix oops and possible deadlocks
Date: Wed, 10 Oct 2018 14:43:09 +0200	[thread overview]
Message-ID: <20181010124309.GB12977@linux-x5ow.site> (raw)
In-Reply-To: <20181010122809.GE11507@quack2.suse.cz>

On Wed, Oct 10, 2018 at 02:28:09PM +0200, Jan Kara wrote:
> On Wed 10-10-18 13:42:27, Johannes Thumshirn wrote:
> > On Wed, Oct 10, 2018 at 07:19:00PM +0900, Tetsuo Handa wrote:
> > > On 2018/10/10 19:04, Jan Kara wrote:
> > > > Hi,
> > > > 
> > > > this patch series fixes oops and possible deadlocks as reported by syzbot [1]
> > > > [2]. The second patch in the series (from Tetsuo) fixes the oops, the remaining
> > > > patches are cleaning up the locking in the loop driver so that we can in the
> > > > end reasonably easily switch to rereading partitions without holding mutex
> > > > protecting the loop device.
> > > > 
> > > > I have lightly tested the patches by creating, deleting, and modifying loop
> > > > devices but if there's some more comprehensive loopback device testsuite, I
> > > > can try running it. Review is welcome!
> > > 
> > > Testing on linux-next by syzbot will be the most comprehensive. ;-)
> > 
> > Apart from that blktests has a loop category and I think it could also be
> > worthwhile to add the C reproducer from syzkaller to blktests.
> 
> Yeah, I did run loop tests now and they ran fine. I can try converting the
> syzbot reproducers into something legible but it will take a while.

There is one C repropducer which can be used (it just needs minor
modifications to pass in the device instead of loop0).

See for instance blktests/src/sg/syzkaller1.c

-- 
Johannes Thumshirn                                        SUSE Labs 
jthumshirn@suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N�rnberg
GF: Felix Imend�rffer, Jane Smithard, Graham Norton
HRB 21284 (AG N�rnberg)
Key fingerprint = EC38 9CAB C2C4 F25D 8600 D0D0 0393 969D 2D76 0850

  reply	other threads:[~2018-10-10 12:43 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-10 10:04 [PATCH 0/15 v2] loop: Fix oops and possible deadlocks Jan Kara
2018-10-10 10:04 ` [PATCH 01/15] block/loop: Don't grab "struct file" for vfs_getattr() operation Jan Kara
2018-10-10 10:04 ` [PATCH 02/15] block/loop: Use global lock for ioctl() operation Jan Kara
2018-10-10 10:04 ` [PATCH 03/15] loop: Fold __loop_release into loop_release Jan Kara
2018-10-10 10:04 ` [PATCH 04/15] loop: Get rid of loop_index_mutex Jan Kara
2018-10-10 10:04 ` [PATCH 05/15] loop: Push lo_ctl_mutex down into individual ioctls Jan Kara
2018-10-10 10:04 ` [PATCH 06/15] loop: Split setting of lo_state from loop_clr_fd Jan Kara
2018-10-10 10:04 ` [PATCH 07/15] loop: Push loop_ctl_mutex down into loop_clr_fd() Jan Kara
2018-10-10 10:04 ` [PATCH 08/15] loop: Push loop_ctl_mutex down to loop_get_status() Jan Kara
2018-10-10 10:04 ` [PATCH 09/15] loop: Push loop_ctl_mutex down to loop_set_status() Jan Kara
2018-10-10 10:04 ` [PATCH 10/15] loop: Push loop_ctl_mutex down to loop_set_fd() Jan Kara
2018-10-10 10:04 ` [PATCH 11/15] loop: Push loop_ctl_mutex down to loop_change_fd() Jan Kara
2018-10-10 10:04 ` [PATCH 12/15] loop: Move special partition reread handling in loop_clr_fd() Jan Kara
2018-10-10 10:04 ` [PATCH 13/15] loop: Move loop_reread_partitions() out of loop_ctl_mutex Jan Kara
2018-10-10 10:04 ` [PATCH 14/15] loop: Fix deadlock when calling blkdev_reread_part() Jan Kara
2018-10-10 10:04 ` [PATCH 15/15] loop: Avoid circular locking dependency between loop_ctl_mutex and bd_mutex Jan Kara
2018-10-10 10:19 ` [PATCH 0/15 v2] loop: Fix oops and possible deadlocks Tetsuo Handa
2018-10-10 11:42   ` Johannes Thumshirn
2018-10-10 12:28     ` Jan Kara
2018-10-10 12:43       ` Johannes Thumshirn [this message]
2018-10-16 11:36       ` Jan Kara
2018-10-16 12:04         ` Johannes Thumshirn
2018-10-16 18:16         ` Omar Sandoval
2018-10-17  9:47           ` Jan Kara

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