From: Vince Weaver <vincent.weaver@maine.edu>
Date: Thu, 11 Jan 2018 10:26:14 -0500 (EST)
To: Peter Zijlstra <peterz@infradead.org>
cc: Vince Weaver <vincent.weaver@maine.edu>,
        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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On Thu, 11 Jan 2018, Peter Zijlstra wrote:

> I'm seeing things like:
> 
> Cannot open /sys/kernel/tracing/kprobe_events
> 
> this is likely caused by me not having anything mounted there. Rostedt
> provided the magic incantation to make that work, I'll go try now.

The perf_fuzzer krpobe code is possibly really out of date, I haven't 
really kept up with recent developments and I don't usually fuzz as root.

> At least I seem to have cured all lockdep splats.. of course, the moment
> I hit send on this someone bad is bound to happen.

Should I be trying any of those patches?

Currently I can still lock my machines pretty quickly.  I have been doing 
some more tests.  Machines don't crash if paranoid is "2" but will if 
paranoid is "1".

Vince