From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758699AbYDCN62 (ORCPT ); Thu, 3 Apr 2008 09:58:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756786AbYDCN6U (ORCPT ); Thu, 3 Apr 2008 09:58:20 -0400 Received: from mtagate5.de.ibm.com ([195.212.29.154]:48116 "EHLO mtagate5.de.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756729AbYDCN6T (ORCPT ); Thu, 3 Apr 2008 09:58:19 -0400 Subject: Re: kernel BUG at drivers/block/ub.c:820! From: Martin Schwidefsky Reply-To: schwidefsky@de.ibm.com To: Boaz Harrosh Cc: linux-kernel@vger.kernel.org, k-ueda@ct.jp.nec.com, j-nomura@ce.jp.nec.com, jens.axboe@oracle.com, zaitcev@redhat.com In-Reply-To: <47F4C044.1090609@panasas.com> References: <1207212156.5602.5.camel@localhost> <47F4C044.1090609@panasas.com> Content-Type: text/plain Organization: IBM Corporation Date: Thu, 03 Apr 2008 15:57:25 +0200 Message-Id: <1207231045.9155.6.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2008-04-03 at 14:32 +0300, Boaz Harrosh wrote: > > With git bisect I could came up with: > > 610d8b0c972e3b75493efef8e96175518fd736d3 good > > 3bcddeac1c4c7e6fb90531b80f236b1a05dfe514 compile error > > 5450d3e1d68f10be087f0855d8bad5458b50ecbe compile error > > b8286239ddaf2632cec65c01e68a403ac4c3d079 compile error > > 7d699bafe258ebd8f9b4ec182c554200b369a504 bad > > > > If I replace the BUG() with a printk my kernel survives the usb plug but > > udev doesn't find the stick. > > > > It is not the right fix but what happens if you change above code to this: > > static void ub_end_rq(struct request *rq, unsigned int scsi_status) > { > int error; > > if (scsi_status == 0) { > error = 0; > } else { > error = -EIO; > rq->errors = scsi_status; > } > if (__blk_end_request(rq, error, blk_rq_bytes(rq))) > __blk_end_request(rq, error, ~0); /* <-- added line BUG removed. */ > } > } I've tried this patch: --- snip diff --git a/drivers/block/ub.c b/drivers/block/ub.c index c452e2d..0031e72 100644 --- a/drivers/block/ub.c +++ b/drivers/block/ub.c @@ -808,7 +808,7 @@ static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd) static void ub_end_rq(struct request *rq, unsigned int scsi_status) { - int error; + int error, size; if (scsi_status == 0) { error = 0; @@ -816,8 +816,12 @@ static void ub_end_rq(struct request *rq, unsigned int scsi_status) error = -EIO; rq->errors = scsi_status; } - if (__blk_end_request(rq, error, blk_rq_bytes(rq))) - BUG(); + size = blk_rq_bytes(rq); + if (__blk_end_request(rq, error, size)) { + printk(KERN_WARNING "ub_end_rq: __blk_end_request failed " + "with size %i\n", size); + __blk_end_request(rq, error, ~0); + } } static int ub_rw_cmd_retry(struct ub_dev *sc, struct ub_lun *lun, --- snip The output on the console: # usb 5-4: new high speed USB device using ehci_hcd and address 3 # usb 5-4: configuration #1 chosen from 1 choice # uba: uba1 # usbcore: registered new interface driver ub # Initializing USB Mass Storage driver... # usbcore: registered new interface driver usb-storage # USB Mass Storage support registered. # ub_end_rq: __blk_end_request failed with size 218 # ub_end_rq: __blk_end_request failed with size 218 # ub_end_rq: __blk_end_request failed with size 218 # ub_end_rq: __blk_end_request failed with size 218 I can mount the stick and read files from it without any additional warnings. Just the initial detection seems to create the odd sized requests. -- blue skies, Martin. "Reality continues to ruin my life." - Calvin.