From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763872AbXGTXeF (ORCPT ); Fri, 20 Jul 2007 19:34:05 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S937591AbXGTXdY (ORCPT ); Fri, 20 Jul 2007 19:33:24 -0400 Received: from xenotime.net ([66.160.160.81]:47256 "HELO xenotime.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1762929AbXGTXdH (ORCPT ); Fri, 20 Jul 2007 19:33:07 -0400 Date: Fri, 20 Jul 2007 16:37:35 -0700 From: Randy Dunlap To: Greg KH Cc: Andrew Morton , rdunlap@xenotime.net, Michal Piotrowski , LKML Subject: Re: [broken-out-2007-07-20-00-22] kernel bug at kernel/params:570 Message-Id: <20070720163735.3ba69e1e.rdunlap@xenotime.net> In-Reply-To: <20070720231052.GA19752@suse.de> References: <6bffcb0e0707200932p2b905e21g7970172ca7eb4da7@mail.gmail.com> <20070720225047.GA17520@suse.de> <20070720155912.079c5a27.akpm@linux-foundation.org> <20070720231052.GA19752@suse.de> Organization: YPO4 X-Mailer: Sylpheed 2.4.2 (GTK+ 2.8.10; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Jul 2007 16:10:52 -0700 Greg KH wrote: > On Fri, Jul 20, 2007 at 03:59:12PM -0700, Andrew Morton wrote: > > On Fri, 20 Jul 2007 15:50:47 -0700 > > Greg KH wrote: > > > > > On Fri, Jul 20, 2007 at 06:32:21PM +0200, Michal Piotrowski wrote: > > > > Hi Greg, > > > > > > > > This looks like a sysfs bug > > > > http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/broken-out-2007-07-20-00-22/00003.jpg > > > > > > > > l *kernel_param_sysfs_setup+0x75 > > > > 0xc13c0894 is in kernel_param_sysfs_setup (kernel/params.c:570). > > > > 565 mk->mod = THIS_MODULE; > > > > 566 kobj_set_kset_s(mk, module_subsys); > > > > 567 kobject_set_name(&mk->kobj, name); > > > > 568 kobject_init(&mk->kobj); > > > > 569 ret = kobject_add(&mk->kobj); > > > > 570 BUG_ON(ret < 0); > > > > 571 param_sysfs_setup(mk, kparam, num_params, name_skip); > > > > 572 kobject_uevent(&mk->kobj, KOBJ_ADD); > > > > 573 } > > > > 574 > > > > > > > > http://www.stardust.webpages.pl/files/tbf/bitis-gabonica/broken-out-2007-07-20-00-22/mm-config > > > > > > What kernel version is this happening on? The -mm tree? Can you try > > > Linus's tree instead? > > > > > > It looks like there was some needed information right before the first > > > stack dump, showing exactly what kobject was trying to be added that was > > > already present. Odds are this is a kernel parameter with the same name > > > as a duplicate one within the same module, but the trick is going to be > > > trying to figure out what module is causing this. > > > > > > So it's not a sysfs bug, but rather a driver issue that this is > > > catching. > > > > In that case a BUG was way too harsh treatment, and in fact directly > > contributed to our inability to debug the bug! > > > > Can we wind that back a bit? Add some useful printks and then recover > > in some fashion? > > Sure, I don't mind doing that at all. > > Hm, it looks like Randy added this back in September last year with: > commit d8c7649e99e4b081b624aefe1e77caa30b53cb18 > Author: Randy Dunlap > Date: Fri Sep 29 01:58:55 2006 -0700 > > [PATCH] kernel/params: driver layer error checking > > Check driver layer return values in kernel/params.c > > Signed-off-by: Randy Dunlap > Signed-off-by: Andrew Morton > Signed-off-by: Linus Torvalds > > (wow, I love git and the signed-off-tree for things like this, it's > trivial to find this information out.) > > So I'm guessing he was trying to catch something specific here. > > Randy, any objection to changing that BUG_ON to a printk warning instead > telling the user exactly what needs to be fixed and that the system is > now going to be unstable when any module is unloaded? Of course not (no objection). I added a BUG_ON() ? Shame on me. --- ~Randy *** Remember to use Documentation/SubmitChecklist when testing your code ***