[PATCH] nvme-multipath: fix lockdep WARN due to partition scan work

[Hannes Reinecke]

On 10/23/25 02:19, 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.
> 
> Reported-by: Yi Zhang <yi.zhang at redhat.com>
> Closes: https://lore.kernel.org/linux-block/CAHj4cs8mJ+R_GmQm9R8ebResKAWUE8kF5+_WVg0v8zndmqd6BQ@mail.gmail.com/
> Link: https://lore.kernel.org/linux-block/oeyzci6ffshpukpfqgztsdeke5ost5hzsuz4rrsjfmvpqcevax@5nhnwbkzbrpa/
> Fixes: 1f021341eef4 ("nvme-multipath: defer partition scanning")
> Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki at wdc.com>
> ---
>   drivers/nvme/host/multipath.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
> index 543e17aead12..e35eccacee8c 100644
> --- a/drivers/nvme/host/multipath.c
> +++ b/drivers/nvme/host/multipath.c
> @@ -793,7 +793,7 @@ static void nvme_mpath_set_live(struct nvme_ns *ns)
>   			return;
>   		}
>   		nvme_add_ns_head_cdev(head);
> -		kblockd_schedule_work(&head->partition_scan_work);
> +		queue_work(nvme_wq, &head->partition_scan_work);
>   	}
>   
>   	nvme_mpath_add_sysfs_link(ns->head);

Reviewed-by: Hannes Reinecke <hare at suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare at suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich