From: Dave Chinner <david@fromorbit.com>
To: Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com
Subject: Re: xfs i_lock vs mmap_sem lockdep trace.
Date: Mon, 31 Mar 2014 10:43:35 +1100 [thread overview]
Message-ID: <20140330234335.GB16336@dastard> (raw)
In-Reply-To: <20140329223109.GA24098@redhat.com>
On Sat, Mar 29, 2014 at 06:31:09PM -0400, Dave Jones wrote:
> Not sure if I've reported this already (it looks familiar, though I've not managed
> to find it in my sent mail folder). This is rc8 + a diff to fix the stack usage reports
> I was seeing (diff at http://paste.fedoraproject.org/89854/13210913/raw)
>
> ======================================================
> [ INFO: possible circular locking dependency detected ]
> 3.14.0-rc8+ #153 Not tainted
> -------------------------------------------------------
> git/32710 is trying to acquire lock:
> (&(&ip->i_lock)->mr_lock){++++.+}, at: [<ffffffffc03bd782>] xfs_ilock+0x122/0x250 [xfs]
>
> but task is already holding lock:
> (&mm->mmap_sem){++++++}, at: [<ffffffffae7b816a>] __do_page_fault+0x14a/0x610
>
> which lock already depends on the new lock.
filldir on a directory inode vs page fault on regular file. Known
issue, definitely a false positive. We have to change locking
algorithms to avoid such deficiencies of lockdep (a case of "lockdep
considered harmful", perhaps?) so it's not something I'm about to
rush...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Dave Jones <davej@redhat.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
xfs@oss.sgi.com
Subject: Re: xfs i_lock vs mmap_sem lockdep trace.
Date: Mon, 31 Mar 2014 10:43:35 +1100 [thread overview]
Message-ID: <20140330234335.GB16336@dastard> (raw)
In-Reply-To: <20140329223109.GA24098@redhat.com>
On Sat, Mar 29, 2014 at 06:31:09PM -0400, Dave Jones wrote:
> Not sure if I've reported this already (it looks familiar, though I've not managed
> to find it in my sent mail folder). This is rc8 + a diff to fix the stack usage reports
> I was seeing (diff at http://paste.fedoraproject.org/89854/13210913/raw)
>
> ======================================================
> [ INFO: possible circular locking dependency detected ]
> 3.14.0-rc8+ #153 Not tainted
> -------------------------------------------------------
> git/32710 is trying to acquire lock:
> (&(&ip->i_lock)->mr_lock){++++.+}, at: [<ffffffffc03bd782>] xfs_ilock+0x122/0x250 [xfs]
>
> but task is already holding lock:
> (&mm->mmap_sem){++++++}, at: [<ffffffffae7b816a>] __do_page_fault+0x14a/0x610
>
> which lock already depends on the new lock.
filldir on a directory inode vs page fault on regular file. Known
issue, definitely a false positive. We have to change locking
algorithms to avoid such deficiencies of lockdep (a case of "lockdep
considered harmful", perhaps?) so it's not something I'm about to
rush...
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
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http://oss.sgi.com/mailman/listinfo/xfs
next prev parent reply other threads:[~2014-03-30 23:44 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-29 22:31 xfs i_lock vs mmap_sem lockdep trace Dave Jones
2014-03-29 22:31 ` Dave Jones
2014-03-30 23:43 ` Dave Chinner [this message]
2014-03-30 23:43 ` Dave Chinner
2014-03-30 23:57 ` Al Viro
2014-03-30 23:57 ` Al Viro
2014-03-31 0:40 ` Dave Chinner
2014-03-31 0:40 ` Dave Chinner
2014-04-08 20:40 ` Sasha Levin
2014-04-08 20:40 ` Sasha Levin
2014-04-10 22:52 ` Dave Chinner
2014-04-10 22:52 ` Dave Chinner
2014-03-31 0:20 ` Dave Jones
2014-03-31 0:20 ` Dave Jones
2014-03-31 0:42 ` Dave Chinner
2014-03-31 0:42 ` Dave Chinner
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