From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: uas: kernel BUG at block/blk-tag.c:89 is back again :| Date: Mon, 7 Jul 2014 03:10:15 -0700 Message-ID: <20140707101015.GB3544@infradead.org> References: <53B2B4B2.8050100@redhat.com> <20140703060135.GA5292@infradead.org> <53B93FE3.8050607@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:49851 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751409AbaGGKKQ (ORCPT ); Mon, 7 Jul 2014 06:10:16 -0400 Content-Disposition: inline In-Reply-To: <53B93FE3.8050607@redhat.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Hans de Goede Cc: "James E.J. Bottomley" , Sarah Sharp , linux-scsi@vger.kernel.org On Sun, Jul 06, 2014 at 02:24:03PM +0200, Hans de Goede wrote: > Hi, > > On 07/03/2014 08:01 AM, Christoph Hellwig wrote: > > Hi Hans, > > > > please test the path below: > > Note, I did a similar patch a while back, but then it was decided to > try and fix the tear-down ordering instead (which seems to have not > completely fixed the issue). I can't see any sensible way to "fix" the issue. Struct gendisk keeps a reference to the requeue_queue, and a struct gendisk reference is held as long as the block device is open. So whenever you surprise remove a device that is open (usually by having a filesystem mounted on it), the request_queue and it's reference to the tag structure will vastly outlive the Scsi_Host.