From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 21059 invoked by alias); 23 Jul 2012 20:16:57 -0000 Received: (qmail 21051 invoked by uid 22791); 23 Jul 2012 20:16:56 -0000 X-SWARE-Spam-Status: No, hits=-6.2 required=5.0 tests=AWL,BAYES_00,KHOP_RCVD_UNTRUST,RCVD_IN_DNSWL_HI,RCVD_IN_HOSTKARMA_W,SPF_HELO_PASS,TW_XC,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; Mon, 23 Jul 2012 20:16:36 +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 q6NKGKbv002218 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 23 Jul 2012 16:16:20 -0400 Received: from host2.jankratochvil.net (ovpn-116-30.ams2.redhat.com [10.36.116.30]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q6NKGG3p018858 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Mon, 23 Jul 2012 16:16:18 -0400 Date: Mon, 23 Jul 2012 20:16:00 -0000 From: Jan Kratochvil To: Philippe Waroquiers Cc: Joel Brobecker , gdb-patches@sourceware.org, Pedro Alves Subject: Re: [patch] [i386] Put hlt at the ON_STACK breakpoint [Re: GDB 7.4.91 available for testing] Message-ID: <20120723201611.GA19567@host2.jankratochvil.net> References: <20120718163413.GA17548@adacore.com> <1342739016.2220.32.camel@soleil> <20120720071158.GA7053@host2.jankratochvil.net> <1342817409.2149.41.camel@soleil> <20120722173053.GA22036@host2.jankratochvil.net> <1342983655.2301.55.camel@soleil> <20120723072125.GA12958@host2.jankratochvil.net> <20120723155951.GA24718@adacore.com> <20120723163513.GA1222@host2.jankratochvil.net> <1343074047.2209.23.camel@soleil> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1343074047.2209.23.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/msg00472.txt.bz2 On Mon, 23 Jul 2012 22:07:27 +0200, Philippe Waroquiers wrote: > Note that the trap instruction should only be written by the > push_dummy_code function : for Normal breakpoints, only a Z0 packet > should be done, as Valgrind will not allow to modify the guest > executable code (it is not mapped writable). I do not understand now what is and what is not allowed for valgrind to write. For the inferior call to work at all you have to create the stack frame for it, otherwise it cannot work, at least for parameters passed by stack. So the GDB patch is no longer needed when you have fixed valgrind to put 0xcc during Z0? Why valgrind cannot write 0xcc into stack memory when it already has to write there to create the stack frame / parameters passed by stack? (Yes, I should read valgrind source code instead.) IIUC the 'hlt' cleanup patch can go only for 7.6 as 7.5 should not regress with new/fixed valgrind. Thanks, Jan