From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32195 invoked by alias); 18 May 2012 17:44:34 -0000 Received: (qmail 32099 invoked by uid 22791); 18 May 2012 17:44:32 -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; Fri, 18 May 2012 17:44:19 +0000 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q4IHiJ0u004593 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 18 May 2012 13:44:19 -0400 Received: from barimba (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id q4IHiHKe006957 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 18 May 2012 13:44:18 -0400 From: Tom Tromey To: Jan Kratochvil Cc: gdb-patches@sourceware.org Subject: Re: [downstream patch FYI] workaround stale frame_info * (PR 13866) References: <20120404191416.GA29603@host2.jankratochvil.net> Date: Fri, 18 May 2012 17:44:00 -0000 In-Reply-To: <20120404191416.GA29603@host2.jankratochvil.net> (Jan Kratochvil's message of "Wed, 4 Apr 2012 21:14:16 +0200") Message-ID: <87obplgz9q.fsf@fleche.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.0.95 (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: 2012-05/txt/msg00699.txt.bz2 >>>>> "Jan" == Jan Kratochvil writes: Jan> With proper C++ sanity check of stale live frame_info references Jan> the testcase would be simple without the "frame_garbage_collection" Jan> reproducer below. It is also reproducible just with valgrind but Jan> regularly running the whole testsuite under valgrind I did not find Jan> feasible. I was thinking about this problem recently. One idea would be to only let unwinders access struct frame_info, and have all other code use struct frame_id, perhaps with some simple cache so that repeated calls for a given frame_id will not cause too much work. This would make it much harder to cache information when not allowed. On the minus side, there are 1300 uses of struct frame_info to audit. Tom