Re: [PATCH v3] nvme-tcp: lockdep: use dynamic lockdep keys per socket instance

[Keith Busch <kbusch@kernel.org>]

On Thu, Jun 04, 2026 at 11:32:08AM +0900, Shin'ichiro Kawasaki wrote:
> When NVMe-TCP controller setup and teardown are repeated with lockdep
> enabled, lockdep reports false positives WARN for the following locks:
> 
>   1) &q->elevator_lock        : IO scheduler change context
>   2) &q->q_usage_counter(io)  : SCSI disk probe context
>   3) fs_reclaim               : CPU hotplug bring-up context
>   4) cpu_hotplug_lock         : socket establishment context
>   5) sk_lock-AF_INET-NVME     : MQ sched dispatch context for the socket
>   6) set->srcu                : NVMe controller delete context
> 
> The lockdep WARN was observed by running blktests test case nvme/005 for
> tcp transport on v7.1-rc1 kernel with a patch. Refer to the Link tag for
> the details of the WARN.
> 
> This is a false positive because lockdep confuses lock 4) (socket
> establishment) with lock 5) (socket in use) for different socket
> instances. The locks belong to different sockets, but lockdep treats
> them as the same due to shared static lockdep keys.

Thanks, applied to nvme-7.2.