From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 19931 invoked by alias); 19 Nov 2014 09:58:53 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 19918 invoked by uid 89); 19 Nov 2014 09:58:52 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Wed, 19 Nov 2014 09:58:51 +0000 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id sAJ9wkeg015288 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Wed, 19 Nov 2014 04:58:46 -0500 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx09.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id sAJ9wi2b013479; Wed, 19 Nov 2014 04:58:45 -0500 Message-ID: <546C69D4.5090300@redhat.com> Date: Wed, 19 Nov 2014 09:58:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1 MIME-Version: 1.0 To: Joel Brobecker CC: gdb-patches@sourceware.org Subject: Re: [RFA/Linux] Ask kernel to kill inferior when GDB terminates References: <1415984034-27122-1-git-send-email-brobecker@adacore.com> <54663729.6010708@redhat.com> <20141114173255.GD5774@adacore.com> <20141119092547.GP5774@adacore.com> In-Reply-To: <20141119092547.GP5774@adacore.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SW-Source: 2014-11/txt/msg00438.txt.bz2 On 11/19/2014 09:25 AM, Joel Brobecker wrote: >>> I could see this making some sense when GDB has spawned the process, >>> but it seems harsh when GDB has attached to the process instead >>> of spawning it? >> >> Hmmm, good point. I'd like to verify what happens in that case, and >> whether the process remains stopped or if execution resumes in that >> case. > > I took a little bit of time to experiment today. The experimentation > was conducted with Linux 3.13.0-39-generic from x86_64 Ubuntu. > In both cases, when GDB runs the program or attaches to a program, > killing GDB while the inferior is still running detaches GDB from > the inferior, which means it keeps running. Sorry, I didn't realize you meant to verify what happens without the patch. Yeah, it's because the ptracer always detaches that the option was introduced, not that long ago. Note that with PTRACE_TRACEME there's still a time window between starting to trace a task and setting its ptrace options, where GDB could crash, and thus we can still miss killing the tracee. To completely close that, we'd have to switch to use the newer PTRACE_SEIZE instead, which takes the ptrace options as argument, but that'd be a story of its own. > I will adapt my patch when I have a moment. Thank you. Pedro Alves