From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (cantor2.suse.de [195.135.220.15]) by ozlabs.org (Postfix) with ESMTP id D4A62B6EFF for ; Wed, 6 Apr 2011 19:07:44 +1000 (EST) Message-ID: <4D9C2D56.70700@suse.cz> Date: Wed, 06 Apr 2011 11:07:34 +0200 From: Michal Marek MIME-Version: 1.0 To: dedekind1@gmail.com Subject: Re: [PATCH 00/34] Make kernel build deterministic References: <1302015561-21047-1-git-send-email-mmarek@suse.cz> <20110405154918.GA31337@suse.de> <1302031447.2608.41.camel@koala> In-Reply-To: <1302031447.2608.41.camel@koala> Content-Type: text/plain; charset=UTF-8 Cc: anil_ravindranath@pmc-sierra.com, mchehab@redhat.com, mac@melware.de, aacraid@adaptec.com, linux-mtd@lists.infradead.org, allan.stephens@windriver.com, hpa@zytor.com, t.sailer@alumni.ethz.ch, gwingerde@gmail.com, x86@kernel.org, elf@buici.com, cluster-devel@redhat.com, ccaulfie@redhat.com, mingo@redhat.com, dougthompson@xmission.com, tipc-discussion@lists.sourceforge.net, dwmw2@infradead.org, linux-media@vger.kernel.org, arnaud.giersch@free.fr, linux-kbuild@vger.kernel.org, IvDoorn@gmail.com, teigland@redhat.com, tony.olech@elandigitalsystems.com, apw@canonical.com, linux-hams@vger.kernel.org, tglx@linutronix.de, swhiteho@redhat.com, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, jon.maloy@ericsson.com, linux-scsi@vger.kernel.org, netdev@vger.kernel.org, Greg KH , linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org, davem@davemloft.net, linux-usb@vger.kernel.org, James.Bottomley@suse.de, chuanxiao.dong@intel.com, paulus@samba.org, linuxppc-dev@lists.ozlabs.org, bluesmoke-devel@lists.sourceforge.net List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 5.4.2011 21:24, Artem Bityutskiy wrote: > On Tue, 2011-04-05 at 08:49 -0700, Greg KH wrote: >> On Tue, Apr 05, 2011 at 04:58:47PM +0200, Michal Marek wrote: >>> >>> Hi, >>> >>> this series makes it possible to build bit-identical kernel image and >>> modules from identical sources. Of course the build is already >>> deterministic in terms of behavior of the code, but the various >>> timestamps embedded in the object files make it hard to compare two >>> builds, for instance to verify that a makefile cleanup didn't >>> accidentally change something. A prime example is /proc/config.gz, which >>> has both a timestamp in the gzip header and a timestamp in the payload >>> data. With this series applied, a script like this will produce >>> identical kernels each time: >> >> Very nice stuff. Do you want to take the individual patches through one >> of your trees, or do you mind if the subsystem maintainers take them >> through theirs? > > But unfortunately, it is very easy to break this and for sure it'll be > broken very soon. I'm not so pessimistic. 34 patches and 57 files might sound like a lot, but given that this has been accumulating since day one, the cleanup should last for some time. > So additionally, I'd suggest: > 1. Instrument checkpatch.pl and make it err or warn on timestamps. This is patch 34/34 in this series: https://lkml.org/lkml/2011/4/5/198 > 2. Probably instrument linux-next to rise a warning when people break > this. I'm not sure if Stephen has that much spare time, and I don't think it is necessary. I think the checkpatch check is sufficient and I'll check myself occasionally. Michal