[PATCH v2] nvmet: Fix fatal_err_work deadlock

[James Smart]

On 10/24/2017 12:31 AM, Sagi Grimberg wrote:
>
>>> If fatal_err_work calls ->delete_ctrl() and that in turn gets to put 
>>> the
>>> last reference on the ctrl it will end up in ->free_ctrl() under
>>> fatal_err_work context which will then try to flush fatal_err_work.
>>
>> Yes, and the way I understand flush_work that is perfectly fine for
>> flush_work, just not for cancel_work_sync.
>
> Really?
>
> My understanding is that flush_work() is inserting a barrier work
> into the worker running the work right after the running work and waits
> for it to complete.
>
> How will the barrier complete without the current work completing?
>
> James, can you give it a shot?
Sagi is correct.

The patch version that solves this problem is v2:
http://lists.infradead.org/pipermail/linux-nvme/2017-October/013505.html

-- james