zfs panic in zfs:vdev_disk_open.part.4

[David Brownlee <abs%absd.org@localhost>]

I'm seeing a (new?) panic on netbsd-9 with zfs. It seems to trigger
when a newly created zfs pool attempts to be mounted:

panic: vrelel: bad ref count
cpu0: Begin traceback...
vpanic() at netbsd:vpanic+0x160
vcache_reclaim() at netbsd:vcache_reclaim
vrelel() at netbsd:vrelel+0x22e
vdev_disk_open.part.4() at zfs:vdev_disk_open.part.4+0x44e
vdev_open() at zfs:vdev_open+0x9e
vdev_open_children() at zfs:vdev_open_children+0x39
vdev_root_open() at zfs:vdev_root_open+0x33
vdev_open() at zfs:vdev_open+0x9e
vdev_create() at zfs:vdev_create+0x1b
spa_create() at zfs:spa_create+0x28c
zfs_ioc_pool_create() at zfs:zfs_ioc_pool_create+0x19b
zfsdev_ioctl() at zfs:zfsdev_ioctl+0x265
nb_zfsdev_ioctl() at zfs:nb_zfsdev_ioctl+0x38
VOP_IOCTL() at netbsd:VOP_IOCTL+0x54
vn_ioctl() at netbsd:vn_ioctl+0xa5
sys_ioctl() at netbsd:sys_ioctl+0x5ab
syscall() at netbsd:syscall+0x157
--- syscall (number 54) ---
7e047af6822a:
cpu0: End traceback...

Anyone seeing anything similar (I continue to have a bunch of other
boxes which use zfs without issue)

David