From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 5689 invoked by alias); 26 Jul 2012 05:13:35 -0000 Received: (qmail 5677 invoked by uid 22791); 26 Jul 2012 05:13:34 -0000 X-SWARE-Spam-Status: No, hits=-6.3 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; Thu, 26 Jul 2012 05:13:13 +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 q6Q5CvR5028885 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Thu, 26 Jul 2012 01:12:58 -0400 Received: from host2.jankratochvil.net (ovpn-116-33.ams2.redhat.com [10.36.116.33]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id q6Q5CqFB010639 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Thu, 26 Jul 2012 01:12:55 -0400 Date: Thu, 26 Jul 2012 05:13:00 -0000 From: Jan Kratochvil To: Philippe Waroquiers Cc: Joel Brobecker , Pedro Alves , gdb-patches@sourceware.org Subject: Re: [patch] [i386] Put hlt at the ON_STACK breakpoint [Re: GDB 7.4.91 available for testing] Message-ID: <20120726051246.GA11143@host2.jankratochvil.net> References: <20120723072125.GA12958@host2.jankratochvil.net> <20120723155951.GA24718@adacore.com> <20120723163513.GA1222@host2.jankratochvil.net> <1343074047.2209.23.camel@soleil> <20120723201611.GA19567@host2.jankratochvil.net> <1343075809.2209.53.camel@soleil> <501009AE.40901@redhat.com> <1343247870.2240.29.camel@soleil> <20120725212653.GC2767@adacore.com> <1343252775.2240.51.camel@soleil> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1343252775.2240.51.camel@soleil> User-Agent: Mutt/1.5.21 (2010-09-15) X-IsSubscribed: yes 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: 2012-07/txt/msg00601.txt.bz2 On Wed, 25 Jul 2012 23:46:15 +0200, Philippe Waroquiers wrote: > A valid instruction is not enough. We need a valid instruction > that will cause Valgrind to terminate block translation. > The breakpoint trap instruction is ok for that. > (0xcc for x86 and amd64, 0x0005000d for mips32). I understand now that int3 is enough for valgrind. I still do not understand whether hlt is enough for valgrind. I will try how hlt behaves with a testcase. Still as you both (with Joel) seem to prefer int3 over hlt I will put int3 there. IIUC your goals this will make false feeling to the user s/he understands what is going which seems to be better than if the user sees hlt which may be more unclear to him/her. Thanks, Jan