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Date: Thu, 1 Dec 2016 10:32:09 -0500
From: Dave Jones <davej@codemonkey.org.uk>
To: Chris Mason <clm@fb.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Jens Axboe <axboe@fb.com>, Andy Lutomirski <luto@amacapital.net>,
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        Linux Kernel <linux-kernel@vger.kernel.org>,
        Dave Chinner <david@fromorbit.com>
Subject: Re: btrfs_destroy_inode warn (outstanding extents)
Message-ID: <20161201153209.kylizqipi7a2wcpj@codemonkey.org.uk>
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On Wed, Nov 23, 2016 at 02:58:45PM -0500, Dave Jones wrote:
 > On Wed, Nov 23, 2016 at 02:34:19PM -0500, Dave Jones wrote:
 > 
 >  > [  317.689216] BUG: Bad page state in process kworker/u8:8  pfn:4d8fd4
 >  > trace from just before this happened. Does this shed any light ?
 >  > 
 >  > https://codemonkey.org.uk/junk/trace.txt
 > 
 > crap, I just noticed the timestamps in the trace come from quite a bit
 > later.  I'll tweak the code to do the taint checking/ftrace stop after
 > every syscall, that should narrow the window some more.
 > 
 > Getting closer..

Ok, this is getting more like it.
http://codemonkey.org.uk/junk/btrfs-destroy-inode-outstanding-extents.txt

Also same bug, different run, but a different traceview http://codemonkey.org.uk/junk/btrfs-destroy-inode-outstanding-extents-function-graph.txt

(function-graph screws up the RIP for some reason, 'return_to_handler'
 should actually be btrfs_destroy_inode)


Anyways, I've got some code that works pretty well for dumping the
ftrace buffer now when things go awry.  I just need to run it enough
times that I hit that bad page state instead of this, or a lockdep bug first.

	Dave