From: Christoph Hellwig <hch@infradead.org>
To: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Cc: linux-nvme@lists.infradead.org, Keith Busch <kbusch@kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Sagi Grimberg <sagi@grimberg.me>, Yi Zhang <yi.zhang@redhat.com>
Subject: Re: [PATCH] nvme-multipath: fix lockdep WARN due to partition scan work
Date: Wed, 22 Oct 2025 22:54:54 -0700 [thread overview]
Message-ID: <aPnDLr2IiOQUQLKI@infradead.org> (raw)
In-Reply-To: <20251023001937.218014-1-shinichiro.kawasaki@wdc.com>
On Thu, Oct 23, 2025 at 09:19:37AM +0900, Shin'ichiro Kawasaki wrote:
> Blktests test cases nvme/014, 057 and 058 fail occasionally due to a
> lockdep WARN. As reported in the Closes tag URL, the WARN indicates that
> a deadlock can happen due to the dependency among disk->open_mutex,
> kblockd workqueue completion and partition_scan_work completion.
>
> To avoid the lockdep WARN and the potential deadlock, cut the dependency
> by running the partition_scan_work not by kblockd workqueue but by
> nvme_wq.
The partition_scan_work was added in 1f021341eef4 ("nvme-multipath:
defer partition scanning") to get it out of the scan work to avoid
deadlocks. I suspect moving it to the same workqueue might reintroduce
the deadlocks, so we might have to add a new workqueue here. Keith
might remember more.
next prev parent reply other threads:[~2025-10-23 5:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-23 0:19 [PATCH] nvme-multipath: fix lockdep WARN due to partition scan work Shin'ichiro Kawasaki
2025-10-23 5:54 ` Christoph Hellwig [this message]
2025-10-23 14:28 ` Keith Busch
2025-10-28 7:55 ` Shinichiro Kawasaki
2025-10-29 7:54 ` hch
2025-11-05 7:32 ` Hannes Reinecke
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