From mboxrd@z Thu Jan 1 00:00:00 1970 From: Quentin Casasnovas Subject: Re: [PATCH 0/2] Tentative fix for the divide-by-zero on score/paris/.. Date: Wed, 15 Apr 2015 15:46:37 +0200 Message-ID: <20150415134637.GB5947@chrystal.uk.oracle.com> References: <20150414165000.GA19434@roeck-us.net> <1429088078-23827-1-git-send-email-quentin.casasnovas@oracle.com> <552E6722.1080507@roeck-us.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:30032 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752877AbbDONoW (ORCPT ); Wed, 15 Apr 2015 09:44:22 -0400 Content-Disposition: inline In-Reply-To: <552E6722.1080507@roeck-us.net> Sender: linux-next-owner@vger.kernel.org List-ID: To: Guenter Roeck Cc: Quentin Casasnovas , Rusty Russell , lkml , Stephen Rothwell , linux-next On Wed, Apr 15, 2015 at 06:26:58AM -0700, Guenter Roeck wrote: > On 04/15/2015 01:54 AM, Quentin Casasnovas wrote: > > > > Let me know if this makes things better.. > > Hi Guenter, > > the crash is fixed, but now I get > That's a first step.. :) > FATAL: The relocation at __ex_table+0x4 references > [...] > > for parisc:defconfig, > for score:allnoconfig, and > for mn10300:defconfig. Thanks for the testing, much appreciated! > > While I agree that those should get fixed (if they are real problems, > especially the ones for parisc and mn10300), I don't think it is > a good idea to fail the build because of it. That's a tough one.. I think it's pretty bad in general to have some crufts in the ex_table referencing non-executable sections. Note that it will not make the build fail if the relocation _seems_ legit (jump to an executable section even though it's not part of the white-list) but in those cases, something really does look wrong and could potentially have a security impact so I thought the build failure was a good thing to do. Now, if it's a problem in modpost (which is likely!), then obviously I'd be happy to try and help fix that! > > Note that I did find the problem in the score build; that was a real bug. > I don't know what may be wrong with the others. Cool! Mind CC'ing me to your fix, I'm curious :) Regarding the others, if you've compiled them with debug information, you should be able to do some addr2line magic incantation to find the offending code. I've also added scripts/check_extable.sh which you might be able to use to get more details about the failures (or simply use the same logic in there to know where those maybe-wrong-relocations are coming from). I'm surprised/concerned that some sections appear to have no name though (indicating yet another bug in my modpost changes?).. If you can share the object files then I can have a look (and possibly help with the addr2line incantation). Thanks! Quentin