From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755575AbbGCP2p (ORCPT ); Fri, 3 Jul 2015 11:28:45 -0400 Received: from www.linutronix.de ([62.245.132.108]:48760 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932122AbbGCP2h (ORCPT ); Fri, 3 Jul 2015 11:28:37 -0400 Date: Fri, 3 Jul 2015 17:28:32 +0200 (CEST) From: Thomas Gleixner To: Jan Kara cc: Ingo Molnar , Borislav Petkov , Linus Torvalds , linux-kernel@vger.kernel.org, x86@kernel.org Subject: Re: Non-booting current Linus' tree In-Reply-To: <20150703152303.GA14041@quack.suse.cz> Message-ID: References: <20150703152303.GA14041@quack.suse.cz> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 3 Jul 2015, Jan Kara wrote: > so I was wondering why I cannot boot current Linus' tree in my kvm > instance. The boot dies after writing "Booting the kernel" message. After > some bisection I have identified the culprit is in commit > 91a8c2a5b43fc4be4adb4bda50cd331697e289e0 (x86/fpu: Clean up and fix MXCSR > handling). After applying that commit I start to get oopses like: At least you get oopses. My hardware simply refused to spit out anything useful and my bisect just ended up at the same commit. > And indeed the oops happens at: > 2b:* 0f ae 85 00 fe ff ff fxsave -0x200(%rbp) <-- > trapping instruction > > Because the address isn't 32-byte aligned (which I assume is the > requirement from looking into the code). So clearly my gcc messed up and > miscompiled the thing by ignoring the alignment attribute. Now my build > host is rather old installation (SLES 11 SP3) running gcc 4.3.4 but there > are quite a few installations of it still running. So do we care or should > I just upgrade the build host? My gcc is old as well. 4.3.0-8. Thanks, tglx