Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754748AbZDYXTT (ORCPT ); Sat, 25 Apr 2009 19:19:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753305AbZDYXTJ (ORCPT ); Sat, 25 Apr 2009 19:19:09 -0400 Received: from gw.goop.org ([64.81.55.164]:50522 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753187AbZDYXTI (ORCPT ); Sat, 25 Apr 2009 19:19:08 -0400 Message-ID: <49F39A69.3090906@goop.org> Date: Sat, 25 Apr 2009 16:19:05 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Bryan Donlan CC: LKML , xen-devel@lists.xensource.com Subject: Re: Bug: ptrace issues under x86_64 Xen kernel 2.6.29 References: <3e8340490903252341u55abbc3aree9afc1b0a7703e6@mail.gmail.com> <49D0361C.3060901@goop.org> <3e8340490904251510r5938b773r7b313555c91e214a@mail.gmail.com> In-Reply-To: <3e8340490904251510r5938b773r7b313555c91e214a@mail.gmail.com> X-Enigmail-Version: 0.95.6 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1327 Lines: 34 Bryan Donlan wrote: > On Sun, Mar 29, 2009 at 11:01 PM, Jeremy Fitzhardinge wrote: > >> Bryan Donlan wrote: >> >>> Using 2.6.29 or 2.6.28 as a 64-bit Xen domU, a number of ptrace() >>> users seem to have issues with unexpected breakpoints. ltrace and gdb >>> both seem to be affected, under both 64-bit and 32-bit userspace. >>> 32-bit kernels do not seem to be affected. Typical symptoms look like: >>> >>> >> It looks like this is because the kernel sets up int3 (breakpoint) and debug >> (watchpoints, etc) to be on a separate debug stack in the tss. Xen doesn't >> do this (and doesn't appear to have a mechanism to do so), so I guess the >> on-stack format isn't what the kernel expects. Does the patch below work? >> > > Hi, > > Sorry for the late reply; this message never made it to my inbox for > some reason... > I did try the patch, and saw similar results to Mark; ptrace works, > but lots of warnings: > Thanks. Those warnings are harmless, but I have an updated version of the fix to suppress them in xen-tip/next. J -- 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/