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Date: Mon, 5 Mar 2012 21:35:58 +0000
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Miles Lane <miles.lane@gmail.com>, LKML <linux-kernel@vger.kernel.org>,
        "Theodore Ts'o" <tytso@mit.edu>,
        Andreas Dilger <adilger.kernel@dilger.ca>,
        Tyler Hicks <tyhicks@canonical.com>,
        Dustin Kirkland <dustin.kirkland@gazzang.com>,
        ecryptfs@vger.kernel.org
Subject: Re: Linus GIT (3.3.0-rc6+) -- INFO: possible circular locking
 dependency detected
Message-ID: <20120305213557.GO23916@ZenIV.linux.org.uk>
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On Mon, Mar 05, 2012 at 01:23:34PM -0800, Andrew Morton wrote:
> mmap_sem nests inside i_mutex.
> 
> On the path
> 
> 	munmap
> 	->ecryptfs_vma_close
> 	  ->filemap_write_and_wait
> 	    ->generic_file_aio_write
> 
> we're taking i_mutex inside mmap_sem.  So the problem is triggered by
> ecryptfs_vma_close() calling filemap_write_and_wait() inside munmap()'s
> mmap_sem.
> 
> Question is: what did we recently change to cause this to happen?

AFAICS, it's commit 32001d6fe9ac6b0423e674a3093aa56740849f3b
Author: Tyler Hicks <tyhicks@canonical.com>
Date:   Mon Nov 21 17:31:29 2011 -0600

    eCryptfs: Flush file in vma close