From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936221AbXGTXLf (ORCPT ); Fri, 20 Jul 2007 19:11:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757636AbXGTXL2 (ORCPT ); Fri, 20 Jul 2007 19:11:28 -0400 Received: from cantor2.suse.de ([195.135.220.15]:46844 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756477AbXGTXL1 (ORCPT ); Fri, 20 Jul 2007 19:11:27 -0400 Date: Fri, 20 Jul 2007 16:10:52 -0700 From: Greg KH To: Andrew Morton , rdunlap@xenotime.net Cc: Michal Piotrowski , LKML Subject: Re: [broken-out-2007-07-20-00-22] kernel bug at kernel/params:570 Message-ID: <20070720231052.GA19752@suse.de> References: <6bffcb0e0707200932p2b905e21g7970172ca7eb4da7@mail.gmail.com> <20070720225047.GA17520@suse.de> <20070720155912.079c5a27.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070720155912.079c5a27.akpm@linux-foundation.org> User-Agent: Mutt/1.5.15 (2007-04-06) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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? thanks, greg k-h