From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 25086 invoked by alias); 19 Feb 2003 17:28:33 -0000 Mailing-List: contact gdb-patches-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sources.redhat.com Received: (qmail 25079 invoked from network); 19 Feb 2003 17:28:32 -0000 Received: from unknown (HELO crack.them.org) (65.125.64.184) by 172.16.49.205 with SMTP; 19 Feb 2003 17:28:32 -0000 Received: from nevyn.them.org ([66.93.61.169] ident=mail) by crack.them.org with asmtp (Exim 3.12 #1 (Debian)) id 18lZuR-0006lC-00; Wed, 19 Feb 2003 13:29:35 -0600 Received: from drow by nevyn.them.org with local (Exim 3.36 #1 (Debian)) id 18lY1F-0002PF-00; Wed, 19 Feb 2003 12:28:29 -0500 Date: Wed, 19 Feb 2003 17:28:00 -0000 From: Daniel Jacobowitz To: Andrew Cagney Cc: Elena Zannoni , gdb-patches@sources.redhat.com Subject: Re: [RFC] PTRACE_ATTACH problem on new Linux kernels Message-ID: <20030219172829.GA9231@nevyn.them.org> Mail-Followup-To: Andrew Cagney , Elena Zannoni , gdb-patches@sources.redhat.com References: <15953.34032.985446.344226@localhost.redhat.com> <20030218022401.14C7E3CF3@localhost.redhat.com> <20030218031431.GA31807@nevyn.them.org> <3E53BDD0.70601@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3E53BDD0.70601@redhat.com> User-Agent: Mutt/1.5.1i X-SW-Source: 2003-02/txt/msg00420.txt.bz2 On Wed, Feb 19, 2003 at 12:24:32PM -0500, Andrew Cagney wrote: > >But Roland made a very convincing case for this new behavior; for > >programs like strace which just pass all signals through, this prevents > >SIGSTOPs being silently cancelled, which is a definite plus. > > Er, humor me. Does it work? > > GDB's problem was that it would pass down the sigstop and then promptly > get it back again (via wait?). Wouldn't strace suffer the same problem? > Unless the sigstop really is delivered that is. Right now, you'll just get it back. The reason is that one of them is the wait associated with ptrace delivery of a SIGSTOP, and the other is the wait associated with our child actually _stopping_. However, shortly you'll be able to distinguish the two, thanks to another one of Roland's bright ideas. The first one will have an event flag marking it as a signal. -- Daniel Jacobowitz MontaVista Software Debian GNU/Linux Developer