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Date: Mon, 24 Oct 2016 13:16:35 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>, linux-kernel@vger.kernel.org,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Andy Lutomirski <luto@kernel.org>
Subject: Re: perf: perf_fuzzer triggers vmalloc_fault (then crashes)
Message-ID: <20161024111635.GH3102@twins.programming.kicks-ass.net>
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On Mon, Oct 24, 2016 at 06:14:02AM -0500, Josh Poimboeuf wrote:

> > Josh, Andy, any clue on how I should go about fixing this?
> 
> This is a bug in the unwinder.  The NMI hit in the entry code right
> after setting up the stack pointer from cpu_current_top_of_stack, so the
> kernel stack was empty.  __unwind_start() tried to dereference the
> pointer (0xffffc90008500000) at the top of the stack.  I'll make a
> patch.

Great, thanks!