[SPDK] Unable to run OCF bdev, bdev not attached

./rpc.py bdev_nvme_attach_controller -b Nvme0 -t PCIe -a 0000:3b:00.0
./rpc.py bdev_aio_create /dev/sdk1 Aio0 512
./rpc.py bdev_ocf_create Cache0 wb Nvme0n1 Aio0 --cache-line-size 64


Inserting cache Cache0
Cache0: Metadata initialized
Cache0: Successfully added
Cache0: Cache mode : wb
Cache0: Attaching cache device failed
vbdev_ocf.c:1016:start_cache_cmpl: *ERROR*: Error -1000013 during start cache Cache0, starting rollback
Cache0: Cannot flush cache - cache device is detached
Cache0: Cache Cache0 successfully stopped


Looks like the cache/core device is not attached, what else should I do to make it work?

P.S. I have run Open-CAS-Linux successfully on this machine, so the cas_cache and cas_cache ko are currently loaded. casctl and casadm tools exist as well.