Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752830AbaB0Xrd (ORCPT ); Thu, 27 Feb 2014 18:47:33 -0500 Received: from terminus.zytor.com ([198.137.202.10]:33965 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752268AbaB0Xrc (ORCPT ); Thu, 27 Feb 2014 18:47:32 -0500 Message-ID: <530FCE6C.4080808@zytor.com> Date: Thu, 27 Feb 2014 15:46:52 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Steven Rostedt CC: Vince Weaver , Peter Zijlstra , Linux Kernel , Ingo Molnar Subject: Re: perf_fuzzer compiled for x32 causes reboot References: <530B841F.5050803@zytor.com> <530B90A5.3090302@zytor.com> <20140224141329.1cd3bb52@gandalf.local.home> <20140224193043.GP6835@laptop.programming.kicks-ass.net> <530C12CA.6070308@zytor.com> <20140225094352.73e0e28c@gandalf.local.home> <20140227173150.4e5ed747@gandalf.local.home> <530FC1C6.5040209@zytor.com> <20140227183008.6be081b7@gandalf.local.home> In-Reply-To: <20140227183008.6be081b7@gandalf.local.home> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/27/2014 03:30 PM, Steven Rostedt wrote: > On Thu, 27 Feb 2014 14:52:54 -0800 > "H. Peter Anvin" wrote: > >> 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. > > Peter, look at the code. That percpu cr2 is in a #ifdef CONFIG_X86_32 > section. That is, it isn't even executed. That's i386 code. The only > place the cr2 is saved for x86_64 is in entry_64.S. > Right, egg on my face. However, I still think it would make more sense for it to nest the way entry_64.S does if at all possible. That makes this even more confusing, though. I would still like to see what happens with the patch I sent Vince. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/