From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10549 invoked by alias); 18 Jan 2013 17:56:53 -0000 Received: (qmail 10537 invoked by uid 22791); 18 Jan 2013 17:56:52 -0000 X-SWARE-Spam-Status: No, hits=-7.7 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,KHOP_THREADED,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,RP_MATCHES_RCVD,SPF_HELO_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Fri, 18 Jan 2013 17:56:47 +0000 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r0IHuh0X024950 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Fri, 18 Jan 2013 12:56:43 -0500 Received: from [127.0.0.1] (ovpn01.gateway.prod.ext.ams2.redhat.com [10.39.146.11]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id r0IHufo9002489; Fri, 18 Jan 2013 12:56:42 -0500 Message-ID: <50F98CD9.5000600@redhat.com> Date: Fri, 18 Jan 2013 17:56:00 -0000 From: Pedro Alves User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Tom Tromey CC: Pierre Muller , gdb-patches@sourceware.org Subject: Re: catch SIGSEGV in the demangler References: <87fw23o70u.fsf@fleche.redhat.com> <19236.9665638127$1358374641@news.gmane.org> <87622vd2vd.fsf@fleche.redhat.com> <50F93081.1090905@redhat.com> <87pq12a62h.fsf@fleche.redhat.com> <50F96D16.3030502@redhat.com> <87y5fq8odh.fsf@fleche.redhat.com> In-Reply-To: <87y5fq8odh.fsf@fleche.redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org X-SW-Source: 2013-01/txt/msg00444.txt.bz2 On 01/18/2013 04:08 PM, Tom Tromey wrote: > > I'm primarily interested in opinions on whether this is even a good > idea. I'm on the fence about it myself. Me too. I'd rather all bugs in the demangler were fixed. :-) > It's far from clear that it is safe to call throw_exception from a > signal handler. Yeah. It's risky. It uses the heap (malloc/free), so if the wrapped code crashes within malloc or free (e.g., corrupted heap), then the handler may e.g., deadlock (the handler crashing wouldn't be that bad, since we're already crashing). It also calls clear_sigint_flag, which with python enabled is probably not very reentrant or async signal safe either, as it calls into python, which I can imagine to be a problem is you wrap all SEGVs throughtout GDB's execution, instead of just over the demangler, which won't normally call into python. So dunno either. -- Pedro Alves