Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755345AbYFDCQq (ORCPT ); Tue, 3 Jun 2008 22:16:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751847AbYFDCQi (ORCPT ); Tue, 3 Jun 2008 22:16:38 -0400 Received: from nf-out-0910.google.com ([64.233.182.188]:17522 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751774AbYFDCQh (ORCPT ); Tue, 3 Jun 2008 22:16:37 -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=lFtB/yPabCsalY8jFVFXuPMOKh7mE4xLJKbw1tHm3pSCstCDccv4wYI0u1TWM87JOPsyCZiKDhWM7jv0SwHMb0FY1mz7edQIyIpTY/noS460IrMETXvJy+jBT4ZXzQfKvdiBC2VmlO8y8t/L7WV7WSgQZIp7HiIEBEayHW4p2iY= Message-ID: <3877989d0806031916wf11bb2t3847aa630fb39e60@mail.gmail.com> Date: Wed, 4 Jun 2008 10:16:35 +0800 From: "Luming Yu" To: "Petr Tesarik" Subject: Re: [RFC PATCH] set TASK_TRACED before arch_ptrace code to fix a race Cc: "Roland McGrath" , LKML , linux-ia64@vger.kernel.org In-Reply-To: <48455619.6040608@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <3877989d0805211947i54bacc7cv619541e9b40824fb@mail.gmail.com> <3877989d0805251830w70f19e4cu46fbc32148217749@mail.gmail.com> <3877989d0805262031i29db16bcjfa31652afc746b49@mail.gmail.com> <20080527040454.053C526FA9E@magilla.localdomain> <3877989d0805262249yab130cbyfc5f5e54065cec5c@mail.gmail.com> <20080527061209.9A24426FAA6@magilla.localdomain> <1211869515.29836.2.camel@elijah.suse.cz> <3877989d0806022304w35764b17p9d4c3c95eceae0f5@mail.gmail.com> <48450864.6080707@suse.cz> <48455619.6040608@suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1137 Lines: 24 > It's definitely a bug in strace. For some reason (I don't care about) > the execve() syscall produces an extra notification. However, this > notification message is suppressed when SIGTRAP is blocked. This > explains why the test case fails only when SIGTRAP is blocked. This is exact problem I suspected and I was trying to address in my hack.. Since there are several processes involved in the pretty complex ptrace scenario., I need to capture all processes context with kdump to confirm this is exact root-cause for the problem. But kdump doesn't work for me..I'm trying to solve it now.. I'm also in doubt about the semantic correctness of the test case.. Since SIGTRAP is so necessary to get ptrace work, is it legitimate to block it in test case? One more thing I need to say is: Same strace works for utrace enabled kernel on IA64.. If the bug is in strace, how could it happen? -- 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/