From: Chris Mason <chris.mason@oracle.com>
To: Dave Jones <davej@redhat.com>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: btrfs/mmap lockdep report from 3.2
Date: Mon, 9 Jan 2012 20:44:32 -0500 [thread overview]
Message-ID: <20120110014432.GC26546@shiny> (raw)
In-Reply-To: <20120110010331.GA15942@redhat.com>
On Mon, Jan 09, 2012 at 08:03:32PM -0500, Dave Jones wrote:
> Just hit this with Linus' tree as of 37cfc3f67db9f2d907f6bfcfae590cdbbef623e8
>
> Dave
>
> [ 130.932837] ======================================================
> [ 130.933032] [ INFO: possible circular locking dependency detected ]
> [ 130.933032] 3.2.0+ #19 Not tainted
> [ 130.933032] -------------------------------------------------------
> [ 130.933032] firefox/1630 is trying to acquire lock:
> [ 130.933032] (&sb->s_type->i_mutex_key#13){+.+.+.}, at: [<ffffffffa011fd5b>] btrfs_page_mkwrite+0x5b/0x310 [btrfs]
> [ 130.933032]
> [ 130.933032] but task is already holding lock:
> [ 130.933032] (&mm->mmap_sem){++++++}, at: [<ffffffff816a38c8>] do_page_fault+0xe8/0x5d0
> [ 130.933032]
> [ 130.933032] which lock already depends on the new lock.
>From a lockdep point of view, this is real. But the page_mkwrite
code is never called on directories so it is actually safe. We'll fix
it up.
-chris
next prev parent reply other threads:[~2012-01-10 1:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-10 1:03 btrfs/mmap lockdep report from 3.2 Dave Jones
2012-01-10 1:44 ` Chris Mason [this message]
2012-01-17 23:25 ` Jan Kara
2012-01-18 1:06 ` Chris Mason
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