Re: [PATCH 1/1] block: Use RCU in blk_mq_[un]quiesce_tagset() instead of set->tag_list_lock

Bart Van Assche
2025-12-04T20:24:19Z

On 12/4/25 9:57 AM, Mohamed Khalfella wrote:
> I do not see how running this code in another thread will solve the
> problem.
blk_mq_freeze_queue_wait() waits forever because nvme_timeout() waits
for blk_mq_freeze_queue_wait() to finish. Hence, the deadlock can be
solved by removing the blk_mq_quiesce_tagset() call from nvme_timeout()
and by failing I/O from inside nvme_timeout(). If nvme_timeout() fails
I/O and does not call blk_mq_quiesce_tagset() then the
blk_mq_freeze_queue_wait() call will finish instead of triggering a
deadlock. However, I do not know whether this proposal seems acceptable
to the NVMe maintainers.

Bart.