From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21571 invoked by alias); 6 Jun 2012 19:38:51 -0000 Received: (qmail 21563 invoked by uid 22791); 6 Jun 2012 19:38:51 -0000 X-SWARE-Spam-Status: No, hits=-6.5 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,SPF_HELO_PASS,T_RP_MATCHES_RCVD 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; Wed, 06 Jun 2012 19:38:29 +0000 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q56JcTwm004028 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Wed, 6 Jun 2012 15:38:29 -0400 Received: from barimba (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q56JcSwH014411 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Wed, 6 Jun 2012 15:38:28 -0400 From: Tom Tromey To: Jan Kratochvil Cc: Pedro Alves , gdb-patches@sourceware.org Subject: Re: [downstream patch FYI] workaround stale frame_info * (PR 13866) References: <20120404191416.GA29603@host2.jankratochvil.net> <4FCE5B14.4030808@redhat.com> <20120605193920.GA19998@host2.jankratochvil.net> Date: Wed, 06 Jun 2012 19:38:00 -0000 In-Reply-To: <20120605193920.GA19998@host2.jankratochvil.net> (Jan Kratochvil's message of "Tue, 5 Jun 2012 21:39:20 +0200") Message-ID: <87d35cgrik.fsf@fleche.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.97 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain 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: 2012-06/txt/msg00198.txt.bz2 Pedro> I've then ran the whole testsuite with this on, and that didn't catch Pedro> any other problem. You mention in PR13866 many situations with stale Pedro> frame_info; did you have some other way to catch those, Jan> No. This single PR13866 crash and GDB code in general gives me enough Jan> reasoning to believe: Jan> (a) There exist other such crashes in GDB, just not tested by the Jan> testsuite. Jan> (b) More of such crashes will regress by changes in the future. Jan> This is just my personal opinion you may not agree with. Despite the difficulties perhaps we should try to write a static analyzer for this. I am not sure if it could be made reliable enough, but maybe it could. The problem cases are when the analyzer must account for cleanups -- but in this case we might be able to get away with ignoring them. Another idea is to simply get rid of frame_info and have only a frame_id-based API. Tom