From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753439AbaEUVqk (ORCPT ); Wed, 21 May 2014 17:46:40 -0400 Received: from terminus.zytor.com ([198.137.202.10]:42373 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752642AbaEUVqj (ORCPT ); Wed, 21 May 2014 17:46:39 -0400 Message-ID: <537D1E8B.1010505@zytor.com> Date: Wed, 21 May 2014 14:45:47 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Borislav Petkov , Linus Torvalds CC: Jiri Kosina , Andy Lutomirski , Thomas Gleixner , Steven Rostedt , Andi Kleen , "linux-kernel@vger.kernel.org" , Ingo Molnar , "Luck, Tony" Subject: Re: [RFC] x86_64: A real proposal for iret-less return to kernel References: <1400639227.9759.21.camel@pippen.local.home> <20140521163315.GJ21205@pd.tnic> <20140521214319.GF25130@pd.tnic> In-Reply-To: <20140521214319.GF25130@pd.tnic> 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 Adding Tony. On 05/21/2014 02:43 PM, Borislav Petkov wrote: > On Thu, May 22, 2014 at 06:37:26AM +0900, Linus Torvalds wrote: >> Seriously. If an NMI is interrupted by an MCE, you might as well >> consider the machine dead. Don't worry about it. We may or may not >> recover, but it is *not* our problem. > > I certainly like this way of handling it. We can even issue a nice > banner saying something like "You're f*cked - go change hw." > Actually, it would be a lot better to panic than deadlock (HA systems tend to have something in place to catch the panic and/or reboot). Any way we can see if the CPU is already holding that lock and panic in that case? -hpa