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From: Vince Weaver <vincent.weaver@maine.edu>
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Date: Mon, 8 Jan 2018 15:29:42 -0500 (EST)
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To: Ingo Molnar <mingo@kernel.org>
cc: linux-kernel@vger.kernel.org,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
Subject: Re: perf: perf_fuzzer quickly locks up on 4.15-rc7
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On Mon, 8 Jan 2018, Ingo Molnar wrote:
> 
> Note that the page table isolation (PTI) feature has a number of effects on perf 
> and on NMI handlers, so one of the things to try would be to disable PTI.

Yes, it seems to be a KPTI issue.

With KPTI disabled I can fuzz for a few hours, no problems.

With KPTI enabled the perf_fuzzer on this haswell machine will lock up 
within minutes.

It's a hard lockup with nothing over the serial console.  It is not 
deterministic/reproducible either.

Vince