From owner-cvs-src@FreeBSD.ORG Fri Jun 22 16:34:51 2007 Return-Path: X-Original-To: cvs-src@freebsd.org Delivered-To: cvs-src@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 36B7B16A41F; Fri, 22 Jun 2007 16:34:51 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (66-23-211-162.clients.speedfactory.net [66.23.211.162]) by mx1.freebsd.org (Postfix) with ESMTP id B47FC13C448; Fri, 22 Jun 2007 16:34:50 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from localhost.corp.yahoo.com (john@localhost [127.0.0.1]) (authenticated bits=0) by server.baldwin.cx (8.13.8/8.13.8) with ESMTP id l5MGYlNA002579; Fri, 22 Jun 2007 12:34:48 -0400 (EDT) (envelope-from jhb@freebsd.org) From: John Baldwin To: David Xu Date: Fri, 22 Jun 2007 12:14:21 -0400 User-Agent: KMail/1.9.6 References: <200506060513.j565DCur032340@repoman.freebsd.org> <200706192026.41638.jhb@freebsd.org> <4678D5BF.9020609@freebsd.org> In-Reply-To: <4678D5BF.9020609@freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200706221214.23776.jhb@freebsd.org> X-Greylist: Sender succeeded SMTP AUTH authentication, not delayed by milter-greylist-2.0.2 (server.baldwin.cx [127.0.0.1]); Fri, 22 Jun 2007 12:34:48 -0400 (EDT) X-Virus-Scanned: ClamAV 0.88.3/3493/Fri Jun 22 05:18:44 2007 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=4.2 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.1.3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on server.baldwin.cx Cc: cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/kern kern_sig.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 22 Jun 2007 16:34:51 -0000 On Wednesday 20 June 2007 03:22:39 am David Xu wrote: > John Baldwin wrote: > > On Monday 06 June 2005 01:13:11 am David Xu wrote: > > > >>davidxu 2005-06-06 05:13:11 UTC > >> > >> FreeBSD src repository > >> > >> Modified files: > >> sys/kern kern_sig.c > >> Log: > >> Fix a bug relavant to debugging, a masked signal unexpectedly interrupts > >> a sleeping thread when process is being debugged. > >> > >> PR: GNU/77818 > >> Tested by: Sean C. Farley > > > > > > This actually breaks other debugging as now debuggers or other processes using > > procfs/ptrace to catch signals can no longer see ignored signals or > > SIGSTOP/SIGCONT. The latter breaks strace when execing a new child process > > as it opens a race where the child process hangs because the parent doesn't > > ever see that the child process has stopped itself with SIGSTOP (the parent > > resumes it with SIGCONT when it sees that). The signal shouldn't make it to > > the target thread if it is ignored, but the process should be stopped and the > > debugger notified of all signals. > > > > Where can you find the place SIGSTOP can be masked or ignored ? > Though SIGCONT can be ignored but it still can resume a suspended > process. if ignored signals can be seen by debugger, then a sleep(10) > will be interrupted by ignored signals when the process is being > debugged, but will work correctly if it is not being debugged, this > becauses issignal() must be called by debugged thread to report any > signals to debugger, the thread should be woken up. I added a printf to stopevent() for S_SIG and it wasn't invoked for SIGSTOP, so PIOCSTATUS ioctl via procfs never returns a status saying the process is stopped on SIGSTOP. Rather than try to untangle the mess that is the signal code I just patched strace to use the same algo truss does for exec'ing a new child process. 4.x worked fine though both for gdb and the existing strace algo, so 6.x as it currently stands is a regression. -- John Baldwin