From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 20002 invoked by alias); 9 Jul 2010 16:20:18 -0000 Received: (qmail 19960 invoked by uid 22791); 9 Jul 2010 16:20:14 -0000 X-SWARE-Spam-Status: No, hits=-5.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,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, 09 Jul 2010 16:20:06 +0000 Received: from int-mx03.intmail.prod.int.phx2.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.16]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o69GK4FL032638 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Fri, 9 Jul 2010 12:20:04 -0400 Received: from host0.dyn.jankratochvil.net (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1]) by int-mx03.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o69GK1Yv020108 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Fri, 9 Jul 2010 12:20:03 -0400 Received: from host0.dyn.jankratochvil.net (localhost [127.0.0.1]) by host0.dyn.jankratochvil.net (8.14.4/8.14.4) with ESMTP id o69GK1CO025136; Fri, 9 Jul 2010 18:20:01 +0200 Received: (from jkratoch@localhost) by host0.dyn.jankratochvil.net (8.14.4/8.14.4/Submit) id o69GK0RT025127; Fri, 9 Jul 2010 18:20:00 +0200 Date: Fri, 09 Jul 2010 16:20:00 -0000 From: Jan Kratochvil To: loody Cc: gdb@sourceware.org Subject: Re: some questions about kernel debugging Message-ID: <20100709162000.GA25084@host0.dyn.jankratochvil.net> References: <20100709130708.GA13468@host0.dyn.jankratochvil.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-12-10) X-IsSubscribed: yes Mailing-List: contact gdb-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-owner@sourceware.org X-SW-Source: 2010-07/txt/msg00039.txt.bz2 On Fri, 09 Jul 2010 17:56:35 +0200, loody wrote: > 2010/7/9 Jan Kratochvil : > > Besides resolving this -O2 -g problem at GCC the easy way is always to just > > `disassemble' the code in GDB, guess from the code+source in which > > register/memory is the value probably located and access it directly there. > > I tried compile the kernel with -O1 -g but it still fail. -O1 should be like -O2 for the debugging... > does that mean only program compiled with -O0 -g will not get the > error message when trying to see the variable? Right. If you succeed to build Linux kernel with -O0 -g (which I doubt) then GCC should produce correct enough debug information that GDB will be happy. Regards, Jan