Re: uas: kernel BUG at block/blk-tag.c:89 is back again :|

[Hans de Goede <hdegoede@redhat.com>]

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 <hch@lst.de>
>> 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