From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH scsi-misc-2.6 08/08] scsi: fix hot unplug sequence Date: Thu, 24 Mar 2005 18:45:58 -0600 Message-ID: <1111711558.5612.52.camel@mulgrave> References: <20050323021335.960F95F8@htj.dyndns.org> <20050323021335.4682C732@htj.dyndns.org> <1111550882.5520.93.camel@mulgrave> <4240F5A9.80205@gmail.com> <20050323071920.GJ24105@suse.de> <1111591213.5441.19.camel@mulgrave> <20050323152550.GB16149@suse.de> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Received: from stat16.steeleye.com ([209.192.50.48]:32410 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S261341AbVCYAqJ (ORCPT ); Thu, 24 Mar 2005 19:46:09 -0500 In-Reply-To: <20050323152550.GB16149@suse.de> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jens Axboe Cc: Tejun Heo , SCSI Mailing List , Linux Kernel On Wed, 2005-03-23 at 16:25 +0100, Jens Axboe wrote: > Let me guess, it is hanging in wait_for_completion()? Yes, I have the trace now. Why is curious. This is the trace of the failure: Mar 24 18:40:34 localhost kernel: usb 4-2: USB disconnect, address 3 Mar 24 18:40:34 localhost kernel: sd 0:0:0:0: CMD c25c98b0 done, completing Mar 24 18:40:34 localhost kernel: 0:0:0:0: cmd c25c98b0 returning Mar 24 18:40:34 localhost kernel: 0:0:0:0: cmd c25c98b0 going out <6>Read Capacity (10) 25 00 00 00 00 00 00 00 00 00 Mar 24 18:40:34 localhost kernel: scsi0 (0:0): rejecting I/O to dead device (req c25c98b0) Mar 24 18:40:34 localhost kernel: usb 4-2: new full speed USB device using uhci_hcd and address 4 Mar 24 18:40:34 localhost kernel: scsi1 : SCSI emulation for USB Mass Storage devices Mar 24 18:40:34 localhost kernel: 1:0:0:0: cmd c1a1b4b0 going out <6>Inquiry 12 00 00 00 24 00 The problem occurs when the mid-layer rejects the I/O to the dead device. Here it returns BLKPREP_KILL to the prep function, but after that we never get a completion back. I'll dig around in ll_rw_blk.c to see if I can trace the problem, but you know this code better than I do ... James