Re: zfs panic in zfs:vdev_disk_open.part.4

[Yorick Hardy <yorickhardy%gmail.com@localhost>]

Dear David,

On 2020-11-22, David Brownlee wrote:
> 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

I don't know if it helps, but it looks like vn_close(vp,..) should be called instead
of vrele(vp) at

 https://nxr.netbsd.org/xref/external/cddl/osnet/dist/uts/common/fs/zfs/vdev_disk.c#218

and

 https://nxr.netbsd.org/xref/external/cddl/osnet/dist/uts/common/fs/zfs/vdev_disk.c#250


-- 
Kind regards,

Yorick Hardy