lock order reversal: 1st 0xfffff80004da07c8 zfs (zfs) @ /usr/src/sys/kern/vfs_mount.c:848 2nd 0xfffff8000f8535f0 devfs (devfs) @ /usr/src/sys/kern/vfs_subr.c:2523 stack backtrace: #0 0xffffffff80aae180 at witness_debugger+0x70 #1 0xffffffff80aae074 at witness_checkorder+0xe54 #2 0xffffffff80a26dc2 at __lockmgr_args+0x4c2 #3 0xffffffff80afeebc at vop_stdlock+0x3c #4 0xffffffff810738ea at VOP_LOCK1_APV+0xda #5 0xffffffff80b1fc2a at _vn_lock+0x9a #6 0xffffffff80b10123 at vget+0x63 #7 0xffffffff8092122d at devfs_allocv+0xcd #8 0xffffffff80920d33 at devfs_root+0x43 #9 0xffffffff80b0746e at vfs_donmount+0x144e #10 0xffffffff80b05ff2 at sys_nmount+0x72 #11 0xffffffff80f16b2b at amd64_syscall+0x2db #12 0xffffffff80ef68cb at Xfast_syscall+0xfb Noticed when stopping a ZFS mounted jail. 11.0 Alpha 6
That should say "noticed when _starting_ a ZFS based jail"
fixed in https://cgit.freebsd.org/src/commit?id=dbc689cdef0cc8ff11171642cdcf107dfbc3fb41