From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55562) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3Lqt-0000bw-R0 for qemu-devel@nongnu.org; Wed, 15 Jan 2014 03:29:37 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1W3Lqm-0000Vw-Mj for qemu-devel@nongnu.org; Wed, 15 Jan 2014 03:29:31 -0500 Received: from mx1.redhat.com ([209.132.183.28]:62282) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1W3Lqm-0000Vg-Dv for qemu-devel@nongnu.org; Wed, 15 Jan 2014 03:29:24 -0500 Date: Wed, 15 Jan 2014 16:28:51 +0800 From: Fam Zheng Message-ID: <20140115082851.GA9106@T430.nay.redhat.com> References: <1389632394-10130-1-git-send-email-pbonzini@redhat.com> <1389632394-10130-7-git-send-email-pbonzini@redhat.com> <52D4658E.10203@twiddle.net> <20140114030658.GB9212@T430.nay.redhat.com> <52D54DFE.9090605@twiddle.net> <52D5558D.2010208@redhat.com> <20140114154550.GI15189@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140114154550.GI15189@redhat.com> Subject: Re: [Qemu-devel] [PATCH v15 6/9] module: implement module loading List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: peter.maydell@linaro.org, mjt@tls.msk.ru, qemu-devel@nongnu.org, alex@alex.org.uk, Paolo Bonzini , mrezanin@redhat.com, vilanova@ac.upc.edu, Richard Henderson On Tue, 01/14 15:45, Daniel P. Berrange wrote: > On Tue, Jan 14, 2014 at 04:19:41PM +0100, Paolo Bonzini wrote: > > Il 14/01/2014 15:47, Richard Henderson ha scritto: > > >>>> +echo "CONFIG_STAMP=`date +%s`_$$_$RANDOM" >> $config_host_mak > > >>> >> > > >>> >> I really really don't like random numbers that make for non-repeatable builds. > > >>> >> It's a quality-assurance nightmare. > > >> > > > >> > Can you elaborate this, please? > > > Build systems like we use at Red Hat want to be able to produce bit-for-bit > > > identical binaries when given the exact same input. Using random numbers > > > during the build process prevents that. > > > > I totally agree, but AIUI people wanted the symbol to be something that > > you couldn't know in advance (e.g. when compiling an out-of-tree > > module). For some definition of "couldn't" and "in advance". > > You can't stop a determined person. The goal is really just to make sure > they have to jump through painful hoops if they're going to delibrately > ignore our policy that this is not for 3rd party out of tree modules to > use. > > When doing RHEL / Fedora builds, we *do* want this to change each time > the RPM is rebuilt for a new release. eg any time we add a new patch > to the RPM we want it to change, but if you're just rebuilding an > src.rpm without making changes we don't need it to be different. > > You could use a sha256 sum of 'configure content + version + pkgversion' > to get something that'd change each time distros did a formal new build, > but would still allow reproducible builds. This sounds like a nice solution, I'll adopt. Thanks. Fam