From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760024Ab0JZQfJ (ORCPT ); Tue, 26 Oct 2010 12:35:09 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37492 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752149Ab0JZQfI (ORCPT ); Tue, 26 Oct 2010 12:35:08 -0400 Message-ID: <4CC70333.80400@zytor.com> Date: Tue, 26 Oct 2010 09:34:59 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.9) Gecko/20100921 Fedora/3.1.4-1.fc13 Thunderbird/3.1.4 MIME-Version: 1.0 To: Andi Kleen CC: linux-kvm@vger.kernel.org, avi@redhat.com, linux-kernel@vger.kernel.org Subject: Re: fyi: gcc33-hammer crashes when compiling kvm emulate.c References: <20101026123828.GA30434@basil.fritz.box> In-Reply-To: <20101026123828.GA30434@basil.fritz.box> 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 10/26/2010 05:38 AM, Andi Kleen wrote: > Hi, > > While doing a test run with the minimum supported compiler > I found: > > An old gcc 3.3-hammer segfaults when compiling the current KVM > emulate.c (or rather in x86_emulate_insns) on x86-64. > > The compiler goes into an endless recursion in validate_rtx and then > eventually overflows the stack and dies. > > I minimized a test case, but didn't find a workaround > (minimized test case http://halobates.de/emulate-min.i) > > My guess it's related to some of the inline assembler uses. > > This might be an excuse to bump the minimum compiler version again. > We have said 3.4 minimum for x86 for a long time now, and have an RFC out to bump to 4.1. Unfortunately there isn't a good repo of arch-specific version requirements in the kernel source code; in fact, I just talked to Tony Luck yesterday about the need for that. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.