From: Vince Weaver <vincent.weaver@maine.edu>
Date: Tue, 9 Jan 2018 12:18:26 -0500 (EST)
To: Peter Zijlstra <peterz@infradead.org>
cc: Ingo Molnar <mingo@kernel.org>, linux-kernel@vger.kernel.org,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: perf: perf_fuzzer quickly locks up on 4.15-rc7
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I tried it again with your patch and force_early_printk, no luck.

I can start dropping printks around the NMI code but I feel like I don't 
really know what I'm doing.

Also I managed to hit (presumably) the same bug on a skylake machine.  
That one doesn't have a serial cable hooked up to it, I'll try to see if I 
can find one.

I am running debian-unstable with gcc 7.2 if it makes a difference.

Vince