From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 23940 invoked by alias); 16 Feb 2011 19:45:44 -0000 Mailing-List: contact archer-help@sourceware.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Subscribe: List-Id: Received: (qmail 23929 invoked by uid 22791); 16 Feb 2011 19:45:43 -0000 X-SWARE-Spam-Status: No, hits=-4.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,TW_TG,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Oleg Nesterov X-Fcc: ~/Mail/utrace Cc: Jan Kratochvil , Project Archer Subject: Re: ptrace improvement: PTRACE_O_INHERIT In-Reply-To: Oleg Nesterov's message of Wednesday, 16 February 2011 20:33:56 +0100 <20110216193356.GB15576@redhat.com> References: <20110211192423.78FFC1802A2@magilla.sf.frob.com> <20110211203755.GA5367@redhat.com> <20110212005855.E764C1814A4@magilla.sf.frob.com> <20110212190253.GA31866@redhat.com> <20110214193052.3EC8D1814BA@magilla.sf.frob.com> <20110214193812.GA20765@redhat.com> <20110215003551.BC1EA1802A2@magilla.sf.frob.com> <20110215130805.GA30742@redhat.com> <20110215214333.GA18086@host1.dyn.jankratochvil.net> <20110215215634.2665A1806E0@magilla.sf.frob.com> <20110216193356.GB15576@redhat.com> Message-Id: <20110216194534.2D39018020E@magilla.sf.frob.com> Date: Wed, 16 Feb 2011 19:45:00 -0000 X-SW-Source: 2011-q1/txt/msg00065.txt.bz2 > Even tgkill() can't 100% protect against PID reuse, but I agree it is better. If the process-wide PID (tgid) is not reused, which it never is silently when ptrace'd today, then tgkill does protect completely against TID reuse. With ptrace as it is today, there is only a silent TID reuse risk in the case of MT exec. Thanks, Roland