From: Dave Chinner <david@fromorbit.com>
To: Alexander Beregalov <a.beregalov@gmail.com>
Cc: rjw@sisk.pl, linux-kernel@vger.kernel.org,
kernel-testers@vger.kernel.org, linux-fsdevel@vger.kernel.org,
xfs@oss.sgi.com
Subject: Re: 2.6.27-rc6: lockdep warning: iprune_mutex at shrink_icache_memory+0x38/0x1a8
Date: Tue, 16 Sep 2008 12:52:04 +1000 [thread overview]
Message-ID: <20080916025204.GL5811@disturbed> (raw)
In-Reply-To: <20080913233138.GA19576@orion>
On Sun, Sep 14, 2008 at 03:31:38AM +0400, Alexander Beregalov wrote:
> Hi
>
> [ INFO: possible circular locking dependency detected ]
> 2.6.27-rc6-00034-gd1c6d2e #3
> -------------------------------------------------------
> nfsd/1766 is trying to acquire lock:
> (iprune_mutex){--..}, at: [<c01743fb>] shrink_icache_memory+0x38/0x1a8
>
> but task is already holding lock:
> (&(&ip->i_iolock)->mr_lock){----}, at: [<c021134f>]
> xfs_ilock+0xa2/0xd6
>
>
> I read files through nfs and saw delay for few seconds.
> System is x86_32, nfs, xfs.
> The last working kernel is 2.6.27-rc5,
> I do not know yet is it reproducible or not.
<sigh>
We need a FAQ for this one. It's a false positive. Google for an
explanation - I've explained it 4 or 5 times in the past year and
asked that the lockdep folk invent a special annotation for the
iprune_mutex (or memory reclaim) because of the way it can cause
recursion into the filesystem and hence invert lock orders without
causing deadlocks.....
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2008-09-16 2:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-13 23:31 2.6.27-rc6: lockdep warning: iprune_mutex at shrink_icache_memory+0x38/0x1a8 Alexander Beregalov
2008-09-16 2:52 ` Dave Chinner [this message]
2008-09-16 4:31 ` Grant Coady
[not found] ` <7iduc45t9dvo0396fm78d8uat84uurh131-e09XROE/p8c@public.gmane.org>
2008-09-16 7:03 ` Dave Chinner
2008-09-16 7:35 ` Alexander Beregalov
2008-09-17 18:33 ` Alexander Beregalov
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