From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758981Ab0CMK6M (ORCPT ); Sat, 13 Mar 2010 05:58:12 -0500 Received: from fanny.its.uu.se ([130.238.4.241]:35228 "EHLO fanny.its.uu.se" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758965Ab0CMK6J (ORCPT ); Sat, 13 Mar 2010 05:58:09 -0500 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <19355.28592.418635.593520@pilspetsen.it.uu.se> Date: Sat, 13 Mar 2010 11:57:52 +0100 From: Mikael Pettersson To: Keith Mannthey Cc: lkml , James Smart , Richard Lary Subject: Re: gcc and kernel build trouble report In-Reply-To: <1268437085.7745.62.camel@keith-laptop> References: <1268437085.7745.62.camel@keith-laptop> X-Mailer: VM 7.17 under Emacs 20.7.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Keith Mannthey writes: > Hello, > > At the start of the week I moved kernels forwarded. I tried > 2.6.34-rc1 and 2.6.33-git15. The lpfc fiber channel driver was failing > to load and generating a hardware level pci bus fault that was resetting > the server. There is a small thread on linux-scsi from when I started. > > Tried forward porting know working versions of the driver to the new > kernels but it did not fix the problem. I have to reason to suspect the > actual code in the driver is not really involved with the issue. > > I booted whole older kernels until I sorted out that somewhere post > 2.6.33 stock that issue started. I am not 100% sure where in the kernel > commits the problem starts I just know if is after 2.6.33. > > It was identified that an alternate .config file worked and I decided > to dig on the config options. > > I narrowed the config change down to: > > CONFIG_CC_OPTIMIZE_FOR_SIZE > > I have to set CONFIG_CC_OPTIMIZE_FOR_SIZE=y else I get a pci fault > while failing to load the lpfc driver. As I understand this passes a > different -O flag to the build. > > > Relevant details: > > Hardware: IBM x3550m2 server. Current Intel based 2 socket system, > nothing fancy. > > GCC: gcc version 4.3.4 [gcc-4_3-branch revision 152973] (SUSE Linux) > > Kernels: For sure, 2.6.34-rc1, 2.6.33-git15 have the problem. If the 10 > or so 2.6.33 and before kernels trees I have booted I did not encounter > the issue. > > Config: CONFIG_CC_OPTIMIZE_FOR_SIZE=y or bad things happen. I booted a > ton of .config changes, 100% sure this is it, it has been triple > checked. > > All in all not a fun experience and I don't really have the skills to > fix this issue. I am going to try a different gcc version when I get a > few cycles. > > Any suggestions on what to do with this gcc / kernel build issue? I > found it a little unsettling. Report it to SuSE, who apparently supplied the gcc-4.3.4 you're having issues with. You can also try using self-compiled vanilla gcc-4.3.4 or better 4.4.3. And you can analyze the miscompilation and construct a user-mode test case, although doing that can be difficult and time-consuming.