[PATCHv3 0/2] nvmet: avoid circular locking warning

Keith Busch kbusch at kernel.org
Wed Jan 10 13:38:12 PST 2024


On Wed, Jan 10, 2024 at 04:12:16AM +0000, Shinichiro Kawasaki wrote:
> On Dec 08, 2023 / 13:53, hare at kernel.org wrote:
> > From: Hannes Reinecke <hare at suse.de>
> > 
> > nvmet-rdma and nvmet-tcp trigger a circular locking warning when
> > tearing down; reason is a call to 'flush_workqueue' when creating
> > a new controller which tries to cover for the fact that old controller
> > instances might be in the process of tearing down.
> > However, this is pure speculation as we don't know (and don't check)
> > if there really _are_ controllers in shutdown.
> > And even if there were, that should be short-lived, and would have been
> > resolved by connecting just a tad later.
> > So this patch returns 'controller busy' if we really find ourselves in this
> > situation, allowing the caller to reconnect later.
> 
> Keith,
> 
> Could you consider to upstream these patches for kernel v6.8-rcX? They fix
> lockdep WARNs observed with blktests nvme test groups and rdma/tcp transport.

Definitely, I knew I was forgetting something. Patches applied now for
6.8 and our 2nd merge window pull request will be issued today.



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