Panic with Root on ZFS

[Kristof Provost]

Hi,

I’ running a root-on-ZFS system and reliably see this panic during 
boot:
It’s a raidz vdev. The faulting kernel is r301916 (head).
The last version known to boot it r299060 (head).

panic: solaris assert: refcount(count(&spa->spa_refcount) >= 
spa->spa_minref ||
MUTEX_HELD(&spa_namespace_lock), file: 
/usr/src/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/spa_misc.c, 
line: 863

Unfortunately I can’t get a dump, but here’s a picture of the 
backtrace:
https://people.freebsd.org/~kp/zfs_panic.jpg

Regards,
Kristof