From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: Re: uas: kernel BUG at block/blk-tag.c:89 is back again :| Date: Tue, 08 Jul 2014 13:25:14 +0200 Message-ID: <53BBD51A.4070704@redhat.com> References: <53B2B4B2.8050100@redhat.com> <20140703060135.GA5292@infradead.org> <53B93FE3.8050607@redhat.com> <20140707101015.GB3544@infradead.org> <53BA95C0.3020607@redhat.com> <20140708095317.GA4306@infradead.org> <53BBBFC6.2030205@kernel.dk> <20140708095619.GA11196@infradead.org> <53BBC98C.4070004@kernel.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:21062 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753443AbaGHLZo (ORCPT ); Tue, 8 Jul 2014 07:25:44 -0400 In-Reply-To: <53BBC98C.4070004@kernel.dk> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Jens Axboe , Christoph Hellwig Cc: "James E.J. Bottomley" , Sarah Sharp , linux-scsi@vger.kernel.org Hi, On 07/08/2014 12:35 PM, Jens Axboe wrote: > On 2014-07-08 11:56, Christoph Hellwig wrote: >> On Tue, Jul 08, 2014 at 11:54:14AM +0200, Jens Axboe wrote: >>>> I've posted the patch in reply to another report and added Jens to the >>>> Cc list. As the block maintainer he need to review and merge it. >>> >>> Which patch is this? >> >> This one: >> >> --- >> From: Christoph Hellwig >> Subject: block: don't assume last put of shared tags is for the host >> >> There is no inherent reason why the last put of a tag structure must be >> the one for the Scsi_Host, as device model objects can be held for >> arbitrary periods. Merge blk_free_tags and __blk_free_tags into a single >> funtion that just release a references and get rid of the BUG() when the >> host reference wasn't the last. > > Thanks, applied. I don't think I was ever CC'ed on this one, though. Thanks, good to hear. Can you please add a Cc: stable ? This patch should at least be backported to 3.15, where uas support has been declared stable. With uas it is trivial to trigger the BUG_ON (and break any further device hotplugging) since uas allows for tcq, and thus using tags over usb (with all of its hotplug goodness and badness). Regards, Hans