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Date: Sat, 12 Sep 2015 01:21:54 +0200
From: Christoph Biedl <linux-kernel.bfrz@manchmal.in-ulm.de>
To: Stefan Priebe <s.priebe@profihost.ag>
Cc: Chris Mason <clm@fb.com>, Christoph Hellwig <hch@lst.de>,
        "linux-btrfs@vger.kernel.org" <linux-btrfs@vger.kernel.org>,
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Subject: Re: btrfs regression since 4.X kernel NULL pointer dereference
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Stefan Priebe wrote...

> Thanks. We're using schroot like the user in this bugreport:
> https://bugzilla.kernel.org/show_bug.cgi?id=100911
> 
> But he also claims he found another way to reproduce using vfcgbackup (last
> comment).

FWIW, this was still the same thing, just stripped down to get closer
to the actual cause. It began with building a private Debian package
that has lvm2 as build dependency. Daemons are disabled in the build
chroot (via policy-rc.d) but the vfcgbackup invocation in lvm2's
postinst is still run.

Also, a quick test of Jeff's update to the Bugzilla ticket looks very
good. More tests will follow.

    Christoph