Fatal trap 12: page fault while in kernel mode          [baseline, first fault]
cpuid = 0
fault virtual address	= 0x450
fault code		= supervisor read, page not present
instruction pointer	= 0x2b:0x4ea664        (lwkt_gettoken+0x64)
stack pointer	        = 0x10:0x7fffffdfc840
frame pointer	        = 0x10:0x7fffffdfcdf0
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 0 (swapper)
current thread          = pri 12
 <- SMP: XXX
kernel: type 12 trap, code=0

CPU0 stopping CPUs: 0x0000000000000000
 stopped
Stopped at      0x4ea664:       movq    (%r12),%rax
db>

--- every ddb continue re-faults; the console accumulated 4,186,854 lines of:

Fatal trap 12: page fault while in kernel mode
cpuid = 0
fault virtual address	= 0x458
fault code		= supervisor read, page not present
instruction pointer	= 0x2b:0x4ea58c        (lwkt_relalltokens+0x3c)
stack pointer	        = 0x10:0x7fffffdfbdf0
frame pointer	        = 0x10:0x7fffffdfc400
current process		= 0 (swapper)
current thread          = pri 12 (CRIT)
kernel: type 12 trap, code=0
Stopped at      0x4ea664:       movq    (%r12),%rax
db>

--- symbolization (guest nm -n /usr/obj/usr/src/sys/VKERNEL64/kernel.debug):
00000000004ea550 T lwkt_relalltokens     -> IP 0x4ea58c = +0x3c
00000000004ea600 T lwkt_gettoken         -> IP 0x4ea664 = +0x64
fault VA 0x450 = offsetof(struct nfsmount, nm_token) with nmp == NULL
  (nfs_root: nmp = VFSTONFS(mp) = mp->mnt_data; lwkt_gettoken(&nmp->nm_token))

--- sequence leading in (run.log):
Mounting root from nfs:
DISKLESS 1
nfs_mountroot: interface lo0 ip 10.1.2.3 bcast 10.1.2.255 mask 255.255.255.0
NFS_ROOT: 127.0.0.1:
NFS_ROOT: No FH passed from loader, attempting mount rpc...krpc_call: sosend: 65
krpc_call: sosend: 65
failed error 65.
nfs_mountroot: mount 127.0.0.1: on /: 65
Fatal trap 12: page fault while in kernel mode      <-- immediately; NO "Root mount failed"