WARN_ON hit on __blk_mq_run_hw_queue followed by an Oops

[Gabriel Krisman Bertazi]

Masayoshi Mizuma <m.mizuma at jp.fujitsu.com> writes:

> Is this WARN_ON still appear in 4.7-rc6 ?
> If so, the following patch may fix this problem.
>
> http://lists.infradead.org/pipermail/linux-nvme/2016-July/005303.html

Hi,

I experimented with this patch before and I still could see the issue.

The warning is not the only symptom anymore, as we also may reach a
deadlock while waiting for queues to freeze in the
blk_mq_queue_reinit_notify path. This may or may not be related.

Things are a little confusing yet, but I'm debugging it and made a good
progress on avoiding the warning.  I'll submit a patch soon.

Thanks,

-- 
Gabriel Krisman Bertazi