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Date: Tue, 31 Oct 2017 11:36:26 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Dmitry Vyukov <dvyukov@google.com>
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        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: WARNING in get_pi_state
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On Tue, Oct 31, 2017 at 01:23:13PM +0300, Dmitry Vyukov wrote:

> But having said that, the tun code is not supposed to make the
> reproducer non-working either. E.g. on our systems it just setups tun
> successfully and then proceeds to the actual code that triggers the
> problem. What's the failure mode with tun code on your system? If we
> make it more portable, then such repros will work on your system as
> well.

It completely fails to create a tun (probably don't have support for
that built-in) and then just sits there doing nothing. I didn't spend
too much time analyzing and just ripped it out.