In the meantime I did some more analysis of the problem and can explain
why the panic happens. Two threads are involved in the problem, one runs
the zfs command and wants to do a rollback using an ioctl() on /dev/zfs,
the other runs mountd and tries to do an "unmount exports" with
"export.ex_flags
Old Synopsis: ZFS kernel panic, solaris assert on dsl_prop_unregister
New Synopsis: [zfs] [panic] ZFS kernel panic, solaris assert on
dsl_prop_unregister
Responsible-Changed-From-To: freebsd-bugs->freebsd-zfs-devel
Responsible-Changed-By: linimon
Responsible-Changed-When: Fri Jun 28 19:57:40 UTC
