From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753341AbYE1JOj (ORCPT ); Wed, 28 May 2008 05:14:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751455AbYE1JO3 (ORCPT ); Wed, 28 May 2008 05:14:29 -0400 Received: from rv-out-0506.google.com ([209.85.198.230]:21922 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751086AbYE1JO2 (ORCPT ); Wed, 28 May 2008 05:14:28 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=MW+FNF6yymfl37WQnBdZGx5U0G7yZ6zaetGnqIRQY5xPDWh5nnsVRC3uJxl1ejr8lI/I3iyXtTIHhF0upmawlxAFM4wMV85POOLwXT2SMEfuN6ALa8MFNQb947k8qdroQ2r0MXUBwzM1Q5XLc2UDzAAkP4WvEy+g3pEUEKH6E4I= Message-ID: <3877989d0805280214y645c7e0ex91a95f1fe47a6abf@mail.gmail.com> Date: Wed, 28 May 2008 17:14:28 +0800 From: "Luming Yu" To: "Roland McGrath" Subject: Re: [RFC PATCH] set TASK_TRACED before arch_ptrace code to fix a race Cc: "Petr Tesarik" , LKML , linux-ia64@vger.kernel.org In-Reply-To: <3877989d0805270148h1b9e7972w880e380c2c4c9b09@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <3877989d0805211947i54bacc7cv619541e9b40824fb@mail.gmail.com> <20080523041940.39E8726FA24@magilla.localdomain> <3877989d0805222224n77ce36b6wdf15c4bab330a0f8@mail.gmail.com> <20080526001527.81E1126FA9E@magilla.localdomain> <3877989d0805251830w70f19e4cu46fbc32148217749@mail.gmail.com> <3877989d0805262031i29db16bcjfa31652afc746b49@mail.gmail.com> <20080527040454.053C526FA9E@magilla.localdomain> <3877989d0805262249yab130cbyfc5f5e54065cec5c@mail.gmail.com> <20080527061209.9A24426FAA6@magilla.localdomain> <3877989d0805270148h1b9e7972w880e380c2c4c9b09@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some correction about the test case hang, the ps output should looks like the following: 13925 S+ strace -f ./test1 13926 S+ ./test1 13927 T+ /bin/bash ./test2 I'm trying upstream kdump to get more detailed data for help analysis the scenario.. But unfortunately upstream kernel just hang when I echo c to sysrq-trigger. Downgrade the kernel to 2.6.22, 'echo c' doesn't hang, but I just got "zero" dump file... Will try F9 later... But from the symptom shouldn't we ask this question: why process 13927 can't wake up? Roland, please confirm if ptrace_untrace is the only way to get Traced process wake up? Back up to caller of ptrace_untrace, maybe we can find out why my RFC patch happen to fix the problem... Any suggestions are welcome! --Luming