crash in xfs in current

[Daniel Wagner]

>> I try to reproduce it on 4.6. My steps do not always trigger the crash.
>> So I can't be really sure if 4.6 doesn't show it, it does not happen.
> 
> I have never been able to trigger this in 4.6 and it's my failsafe
> reboot (4.6.0).
> In 4.7-rc1 it's just a matter of time before I hit it.
> I do a lot of transactions, using git, extraction of tar.xz etc normally.

This rings a bell. I though the lockperf tests triggered it. Before I
compiled a new kernel I did a 'git checkout' step.