Fatal double fault

My previous kernel and userland both from 22 Nov. Tonight I have built
new kernel in attempt to test new features. But after boot with new
kernel (and old userland, as I know, installworld should be done with
new kernel) I've got this (sorry, no serial console, I've written 
this on a piece of paper):

<reading sysctl variables...>

Fatal double fault:
eip = 0xc04e4352
esp = 0xd5351f70
ebp = 0xd5352034
pkernel trap 25 with interrupts disabled
panic: double fault
Uptime: 19s

This is sony vaio laptop. Any help very appreciated. Thanks.