Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752619AbcCBVYY (ORCPT ); Wed, 2 Mar 2016 16:24:24 -0500 Received: from mail-qk0-f181.google.com ([209.85.220.181]:35133 "EHLO mail-qk0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750785AbcCBVYX (ORCPT ); Wed, 2 Mar 2016 16:24:23 -0500 MIME-Version: 1.0 In-Reply-To: <20160215115001.GA22934@sudip-pc> References: <56c18a5d.4mR6FT1TNJ7yeYPN%fengguang.wu@intel.com> <20160215115001.GA22934@sudip-pc> Date: Wed, 2 Mar 2016 14:24:22 -0700 Message-ID: Subject: Re: [ppdev] e7223f1860: kernel BUG at drivers/base/driver.c:153! From: Ross Zwisler To: Sudip Mukherjee , Ross Zwisler Cc: kernel test robot , LKP , LKML , Greg Kroah-Hartman , wfg@linux.intel.com Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2214 Lines: 62 On Mon, Feb 15, 2016 at 4:50 AM, Sudip Mukherjee wrote: > On Mon, Feb 15, 2016 at 04:20:45PM +0800, kernel test robot wrote: >> Greetings, >> >> 0day kernel testing robot got the below dmesg and the first bad commit is >> >> https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git char-misc-testing >> >> commit e7223f18603374d235d8bb0398532323e5f318b9 >> Author: Sudip Mukherjee >> AuthorDate: Fri Feb 12 18:33:45 2016 +0530 >> Commit: Greg Kroah-Hartman >> CommitDate: Sun Feb 14 17:43:50 2016 -0800 >> >> ppdev: use new parport device model >> >> Modify ppdev driver to use the new parallel port device model. >> >> Signed-off-by: Sudip Mukherjee >> Signed-off-by: Greg Kroah-Hartman > > Can you please send the .config file so that i can reproduce in my local > system and test? > > Ying Huang also sent a similar report after posting the patches. I tried > his .config and your scripts to reproduce this but was not able to. > > Anyway, this error is not related to this patch, this patch has just > uncovered this error in parport. And will only happen if ppdev tries to > register with parport before parport bus is registered. > Can you please check if the below patch solves the problem: > > > diff --git a/drivers/parport/share.c b/drivers/parport/share.c > index 3308427..176b2b6 100644 > --- a/drivers/parport/share.c > +++ b/drivers/parport/share.c > @@ -273,6 +273,9 @@ int __parport_register_driver(struct parport_driver *drv, struct module *owner, > /* using device model */ > int ret; > > + if (!parport_bus_type.p) > + return -EAGAIN; > + > /* initialize common driver fields */ > drv->driver.name = drv->name; > drv->driver.bus = &parport_bus_type; > > > -- > regards > sudip I've been hitting this error on my KVM system as well, and bisected to the same commit. The patch you have here solved the issue for me. I'm happy to provide kernel config, etc. - let me know what would be helpful. - Ross