From owner-freebsd-hackers@FreeBSD.ORG Thu Nov 25 20:10:36 2010 Return-Path: Delivered-To: hackers@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4B88B10656CB for ; Thu, 25 Nov 2010 20:10:36 +0000 (UTC) (envelope-from erik@cederstrand.dk) Received: from csmtp2.one.com (csmtp2.one.com [91.198.169.22]) by mx1.freebsd.org (Postfix) with ESMTP id DEF998FC20 for ; Thu, 25 Nov 2010 20:10:35 +0000 (UTC) Received: from macfeast.lan (0x573b9942.cpe.ge-1-2-0-1101.ronqu1.customer.tele.dk [87.59.153.66]) by csmtp2.one.com (Postfix) with ESMTPA id 21711DE0F41F7; Thu, 25 Nov 2010 20:10:34 +0000 (UTC) Mime-Version: 1.0 (Apple Message framework v1082) Content-Type: multipart/signed; boundary=Apple-Mail-214-1023505647; protocol="application/pkcs7-signature"; micalg=sha1 From: Erik Cederstrand In-Reply-To: <20101125191727.GB1342@mark-laptop-bsd.mark-home> Date: Thu, 25 Nov 2010 21:10:34 +0100 Message-Id: <0B04A57E-A325-4006-8A01-6C7F15584C2F@cederstrand.dk> References: <93FA0AC7-704D-4EB4-A163-FDD8AC915630@cederstrand.dk> <20101125191727.GB1342@mark-laptop-bsd.mark-home> To: Mark Johnston X-Mailer: Apple Mail (2.1082) X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: FreeBSD Hackers Subject: Re: Deterministic builds, part 2 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 25 Nov 2010 20:10:36 -0000 --Apple-Mail-214-1023505647 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii Den 25/11/2010 kl. 20.17 skrev Mark Johnston: > On Thu, Nov 25, 2010 at 01:08:58PM +0100, Erik Cederstrand wrote: >> Kernel modules: >> ---------------------- >> In the ELF section .gnu-debuglink, there is a link to the = corresponding *.ko.symbols file. It seems to be an inode or such rather = than a file path since nothing shows up in strings(1). I have commented = out "makeoptions DEBUG=3D-g" in the GENERIC kernel conf file which I am = testing now, but I'd like to know what is actually going on. >=20 > The .gnu_debuglink segment contains the name of the debug symbols file > (i.e. not a full path or an inode number). I'm not sure why it doesn't > show up with strings(1), but you can see it with a hex editor. >=20 > When gdb loads an object file with a gnu_debuglink segment, it looks = in > a few pre-defined locations for the corresponding symbols file. The = gdb > docs explain it pretty well: >=20 > http://sourceware.org/gdb/onlinedocs/gdb/Separate-Debug-Files.html Thanks. I was explained in private email that I should be using "strings = -a" which indeed turns up the filename. The checksum mismatch actually = occurs because the section also contains a CRC of the symbols file, = which means the symbols files aren't identical. I'll investigate that = separately. Erik= --Apple-Mail-214-1023505647--