From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933706AbZIDQ45 (ORCPT ); Fri, 4 Sep 2009 12:56:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932871AbZIDQ4y (ORCPT ); Fri, 4 Sep 2009 12:56:54 -0400 Received: from claw.goop.org ([74.207.240.146]:50953 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932870AbZIDQ4y (ORCPT ); Fri, 4 Sep 2009 12:56:54 -0400 Message-ID: <4AA146D6.8030802@goop.org> Date: Fri, 04 Sep 2009 09:56:54 -0700 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.1) Gecko/20090814 Fedora/3.0-2.6.b3.fc11 Lightning/1.0pre Thunderbird/3.0b3 MIME-Version: 1.0 To: Bastian Blank , linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, 544145@bugs.debian.org, Keir Fraser Subject: Re: 32bit binaries on x86_64/Xen segfaults in syscall-vdso References: <20090830181637.GA7155@wavehammer.waldi.eu.org> <4AA02C57.30106@goop.org> <20090903220252.GA19309@wavehammer.waldi.eu.org> <4AA03DE8.40706@goop.org> <20090903223603.GA19945@wavehammer.waldi.eu.org> <4AA13B4B.7020101@goop.org> <20090904162003.GA6147@wavehammer.waldi.eu.org> In-Reply-To: <20090904162003.GA6147@wavehammer.waldi.eu.org> X-Enigmail-Version: 0.97a 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 09/04/09 09:20, Bastian Blank wrote: > On Fri, Sep 04, 2009 at 09:07:39AM -0700, Jeremy Fitzhardinge wrote: > >> But for some reason that's triggering a failsafe callback, which invokes >> a GP. >> > Hmm, not in my tests. It always returned to userspace correctly and died > some operations later, usually the "ret". This then produced either a > segfault (unreadable address), sigill (if it managed to reach the ELF > header of the ld.so) or a GPF. Hm, I may have misdiagnosed it then. Your symptoms are odd; either its landing back in userspace in the right place but then stumbles on for a while before crashing (wrong processor mode?) or the eip is wrong and its just landing in the wrong place and crashing immediately. How non-deterministic is it? Does it differ every time, or from boot to boot, build to build? J