Re: [PATCH 0/15 v2] loop: Fix oops and possible deadlocks

Johannes Thumshirn
2018-10-10T12:43:09Z

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

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