From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756284AbXGBVHV (ORCPT ); Mon, 2 Jul 2007 17:07:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754720AbXGBVHJ (ORCPT ); Mon, 2 Jul 2007 17:07:09 -0400 Received: from gw.goop.org ([64.81.55.164]:58362 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755073AbXGBVHI (ORCPT ); Mon, 2 Jul 2007 17:07:08 -0400 Message-ID: <468968F8.9060700@goop.org> Date: Mon, 02 Jul 2007 14:07:04 -0700 From: Jeremy Fitzhardinge User-Agent: Thunderbird 2.0.0.4 (X11/20070615) MIME-Version: 1.0 To: Jason Wessel CC: lkml , stable@kernel.org, Chuck Ebbert <76306.1226@compuserve.com> Subject: Re: [PATCH] i386 - Fix regression, endless loop in ptrace singlestep over an int80 References: <468965D8.7020405@windriver.com> In-Reply-To: <468965D8.7020405@windriver.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Jason Wessel wrote: > > Attached is a patch with a complete test case to fix the regression > introduced by the commit: 635cf99a80f4ebee59d70eb64bb85ce829e4591f. > > This patch is against kernel 2.6.21 but the fix is applicable to > 2.6.21 and up. Prior to the commit that introduced the regression the > ltp ptrace tests would complete correctly. I augmented the test case > from the original patch header to include the problem case that shows > up in the lpt tests. > > The brief summary is that the the TIF_SINGLESTEP state needs to be > altered on the exit path and not the entry path to a syscall, else it > can loop forever on the same instruction right after the syscall is > executed in certain cases. Looks reasonable to me, but what under what circumstances can TIF_SINGLESTEP get lost? J