From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8425 invoked by alias); 22 Feb 2011 21:10:41 -0000 Mailing-List: contact archer-help@sourceware.org; run by ezmlm Sender: Precedence: bulk List-Post: List-Help: List-Subscribe: List-Id: Received: (qmail 8411 invoked by uid 22791); 22 Feb 2011 21:10:39 -0000 X-SWARE-Spam-Status: No, hits=-6.4 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Date: Tue, 22 Feb 2011 21:10:00 -0000 From: Oleg Nesterov To: Roland McGrath Cc: Jan Kratochvil , Project Archer Subject: Re: ptrace improvement: PTRACE_O_INHERIT Message-ID: <20110222210214.GA8669@redhat.com> References: <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> <20110222204854.DE4D61801F7@magilla.sf.frob.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110222204854.DE4D61801F7@magilla.sf.frob.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-SW-Source: 2011-q1/txt/msg00093.txt.bz2 On 02/22, Roland McGrath wrote: > > > 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. perhaps, I am not sure right now... but > As long as the de_thread delay > is an uninterruptible wait not even affected by SIGKILL, it looks like a > DoS sort of vector Aaahhh. good point, and I never thought about this... this is like vfork(). At first glance it is simple to turn this wait into TASK_KILLABLE, if we stay with the current behaviour. Oleg.