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Date: Mon, 7 Apr 2008 02:01:29 +0100 (BST)
From: Hugh Dickins <hugh@veritas.com>
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To: James Bottomley <James.Bottomley@HansenPartnership.com>
cc: Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>,
       Jens Axboe <jens.axboe@oracle.com>,
       Christoph Lameter <clameter@sgi.com>,
       Pekka Enberg <penberg@cs.helsinki.fi>,
       Peter Zijlstra <a.p.zijlstra@chello.nl>,
       "Rafael J. Wysocki" <rjw@sisk.pl>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] scsi: fix sense_slab/bio swapping livelock
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On Sun, 6 Apr 2008, James Bottomley wrote:
> 
> This was sort of accidentally fixed in scsi-misc by commit 
> 
> commit c5f73260b289cb974928eac05f2d84e58ddfc020
> Author: James Bottomley <James.Bottomley@HansenPartnership.com>
> Date:   Thu Mar 13 11:16:33 2008 -0500
> 
>     [SCSI] consolidate command allocation in a single place

Thanks, yes, that looks a good substitute to me.

> Could you check that:
> 
> master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
> 
> and see if it alleviates the problem? ... if so, we can work out which
> pieces to backport.

Precisely that patch seems appropriate to 2.6.25-rc8-git, so I'm now
running the test with just that applied to 2.6.25-rc8 (plus cfq rcu
fix).  Not quite what you asked, but...

Strictly speaking, it'd take a couple of days to be reasonably sure
that the livelock is gone (it appeared to reproduce quicker once I
moved to -rc8 plus cfq rcu fix; but I'm not entirely convinced that
wasn't just coincidence).  But if nothing bad appears overnight,
let's assume your patch is the one to push: I'll report tomorrow.

Hugh