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From: Mike Snitzer <snitzer@redhat.com>
To: Bart Van Assche <bvanassche@acm.org>
Cc: dm-devel@redhat.com
Subject: Re: 3.15-rc4: circular locking dependency triggered by dm-multipath
Date: Tue, 27 May 2014 09:22:28 -0400	[thread overview]
Message-ID: <20140527132228.GA10955@redhat.com> (raw)
In-Reply-To: <538355B3.9060100@acm.org>

On Mon, May 26 2014 at 10:54am -0400,
Bart Van Assche <bvanassche@acm.org> wrote:

> On 05/26/14 14:51, Hannes Reinecke wrote:
> > Or, better still, try the attached patch.
> > There's one more instance where lockdep might complain.
> 
> Does anyone know whether it's safe to revert commit 4cdd2ad780 ?

Yes, it should be reverted, otherwise multipath_ioctl is using
inconsistent lock order.  I should've waited for test confirmation
before sending the previous "fix" upstream.  It made the lock order
consistent (but consistently wrong).

> Anyway,
> I ran a test with v3.15-rc7 + your patch + 4cdd2ad780 reverted and that
> test ran fine. I didn't encounter any lockups nor any lockdep
> complaints. The test I ran was to run a fio I/O verification test on top
> of a dm-multipath device. That multipath device was created on top of
> several SCSI device nodes created by the ib_srp driver. About once every
> 30 seconds a cable removal / reinsertion was simulated via the
> ibportstate command.

Great, thanks.  I'll try to get this queued for Linus this week.

  reply	other threads:[~2014-05-27 13:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-06  9:31 3.15-rc4: circular locking dependency triggered by dm-multipath Bart Van Assche
2014-05-06 13:22 ` Mike Snitzer
2014-05-06 13:46   ` Bart Van Assche
2014-05-07 20:53 ` Mike Snitzer
2014-05-08  5:57 ` Hannes Reinecke
2014-05-26 11:44   ` Bart Van Assche
2014-05-26 12:10     ` Hannes Reinecke
2014-05-26 12:20       ` Bart Van Assche
2014-05-26 12:29         ` Hannes Reinecke
2014-05-26 12:44           ` Hannes Reinecke
2014-05-26 12:51             ` Hannes Reinecke
2014-05-26 14:54               ` Bart Van Assche
2014-05-27 13:22                 ` Mike Snitzer [this message]
2014-05-27 14:49                   ` Mike Snitzer
2014-05-27 16:09                     ` Bart Van Assche

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