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Date: Wed, 8 Aug 2012 15:17:38 +0800
From: Fengguang Wu <fengguang.wu@intel.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Sasha Levin <levinsasha928@gmail.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Dave Jones <davej@redhat.com>, Kamal Mostafa <kamal@canonical.com>,
        "Peter M. Petrakis" <peter.petrakis@canonical.com>,
        Dann Frazier <dann.frazier@canonical.com>,
        Massimo Morana <massimo.morana@canonical.com>, Jan Kara <jack@suse.cz>,
        linux-fsdevel@vger.kernel.org
Subject: Re: mq: INFO: possible circular locking dependency detected
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On Tue, Aug 07, 2012 at 07:39:55AM +0100, Al Viro wrote:
> On Tue, Aug 07, 2012 at 01:04:12PM +0800, Fengguang Wu wrote:
> 
> > FYI, here is a different back trace on that commit.
> > 
> > [    3.255043] ======================================================
> > [    3.255052] [ INFO: possible circular locking dependency detected ]
> > [    3.255052] 3.5.0-rc6-bisect-00355-geb04c28 #4 Not tainted         
> > [    3.255052] -------------------------------------------------------
> > [    3.255052] init/1 is trying to acquire lock:
> > [    3.255052]  (&mm->mmap_sem){++++++}, at: [<ffffffff81180d00>] might_fault+0x70/0xe0
> > [    3.255052]
> > [    3.255052] but task is already holding lock:
> > [    3.255052]  (&sb->s_type->i_mutex_key){+.+.+.}, at: [<ffffffff811d191e>] vfs_readdir+0x6e/0x130
> 
> Do you see any similar with the _next_ commit?

Stress tests show that the next commit is free from both the "circular
locking dependency" issues.

Thanks,
Fengguang