From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5855 invoked by alias); 16 Feb 2011 20:09:24 -0000 Mailing-List: contact archer-help@sourceware.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Subscribe: List-Id: Received: (qmail 5843 invoked by uid 22791); 16 Feb 2011 20:09:22 -0000 X-SWARE-Spam-Status: No, hits=-6.3 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 Date: Wed, 16 Feb 2011 20:09:00 -0000 From: Oleg Nesterov To: Roland McGrath Cc: Jan Kratochvil , Project Archer Subject: Re: ptrace improvement: PTRACE_O_INHERIT Message-ID: <20110216200110.GA17601@redhat.com> References: <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> <20110216194534.2D39018020E@magilla.sf.frob.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110216194534.2D39018020E@magilla.sf.frob.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SW-Source: 2011-q1/txt/msg00070.txt.bz2 On 02/16, Roland McGrath wrote: > > > Even tgkill() can't 100% protect against PID reuse, but I agree it is better. > > If the process-wide PID (tgid) is not reused > ... > then tgkill does protect completely against TID reuse. How? sooner or later the process which creates/destroys a thread in a loop will reuse some pid number. But probably you meant that tgkill() guarantees it is still in the same process, in this case I agree. Oleg.