amd64 kernel panic on boot

A newly compiled kernel/world today panics jumping to address 0:

Nov  9 12:36:31 server kernel: Fatal trap 12: page fault while in kernel mode
Nov  9 12:36:31 server kernel: fault virtual address    = 0x0
Nov  9 12:36:31 server kernel: fault code               = supervisor read, page
not present
Nov  9 12:36:31 server kernel: instruction pointer      = 0x8:0x0
Nov  9 12:36:31 server kernel: stack pointer            = 0x10:0xffffffffb1c76930
Nov  9 12:36:31 server kernel: frame pointer            = 0x10:0xffffffffb1c76b40
Nov  9 12:36:31 server kernel: code segment             = base 0x0, limit 0xfffff, type 0x1b
Nov  9 12:36:31 server kernel: = DPL 0, pres 1, long 1, def32 0, gran 1
Nov  9 12:36:31 server kernel: processor eflags = interrupt enabled, resume, IOPL = 0
Nov  9 12:36:31 server kernel: current process          = 213 (natd)

I couldn't do any traceback at that point.  My system is amd64 and
kernel config has:

# My additional options
options         COMPAT_43
options         COMPAT_LINUX32
options         LINPROCFS

options         SEMMNI=40
options         SEMMNS=240
options         SEMUME=40
options         SEMMNU=120

options         BRIDGE                  # bridge ethernet adapters

options         IPFIREWALL
options         IPFIREWALL_FORWARD
#options                IPDIVERT

options         DEVICE_POLLING
options         HZ=1000
options         SW_WATCHDOG