From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1806 invoked by alias); 22 Feb 2011 20:49:07 -0000 Mailing-List: contact archer-help@sourceware.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Subscribe: List-Id: Received: (qmail 1795 invoked by uid 22791); 22 Feb 2011 20:49:05 -0000 X-SWARE-Spam-Status: No, hits=-4.8 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,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 Tuesday, 22 February 2011 20:31:24 +0100 <20110222193124.GA3257@redhat.com> References: <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> <20110216200110.GA17601@redhat.com> <20110219194758.GA8994@host1.dyn.jankratochvil.net> <20110219202921.GA12280@redhat.com> <20110221195405.D27B11801F8@magilla.sf.frob.com> <20110222193124.GA3257@redhat.com> Message-Id: <20110222204854.DE4D61801F7@magilla.sf.frob.com> Date: Tue, 22 Feb 2011 20:49:00 -0000 X-SW-Source: 2011-q1/txt/msg00092.txt.bz2 > Unless I missed something again, other threads are visible to wait(). That's what it looks like in the code to me as well. But my recollection is otherwise. And IMHO it should be otherwise, that is that MT exec cannot be arbitrarily delayed by any userland act. As long as the de_thread delay is an uninterruptible wait not even affected by SIGKILL, it looks like a DoS sort of vector if userland can prevent the other threads from dying quickly. Thanks, Roland