linux-kernel - Re: perf_fuzzer compiled for x32 causes reboot

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Message-ID: <530FC1C6.5040209@zytor.com>
Date:	Thu, 27 Feb 2014 14:52:54 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Steven Rostedt <rostedt@...dmis.org>,
	Vince Weaver <vincent.weaver@...ne.edu>
CC:	Peter Zijlstra <peterz@...radead.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...hat.com>
Subject: Re: perf_fuzzer compiled for x32 causes reboot

On 02/27/2014 02:31 PM, Steven Rostedt wrote:
> 
> Yeah, something is getting mesed up.
> 

What it *looks* like to me is that we try to nest the cr2 save/restore,
which doesn't nest because it is a percpu variable.

... except in the x86-64 case, we *ALSO* save/restore cr2 inside
entry_64.S, which makes the stuff in do_nmi completely redundant and
there for no good reason.

I would actually suggest we do the equivalent on i386 as well.

Vince, could you try this patch as an experiment?

View attachment "patch" of type "text/plain" (952 bytes)