i386: 9.99.107 traps booting on VirtualBox

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

I tried to upgrade a 32-bit VBox VM from 9.99.99 to .107 and the
kernel from the yesterday's sources crashes on boot.  

...
attimer1: attached to pcppi0
fatal page fault in supervisor mode
trap type 6 code 0 eip 0xc0d3d808 cs 0x8 eflags 0x10246 cr2 0x3c ilevel 0x7 esp 0x6
curlwp 0xc1657840 pid 0 lid 0 lowest kstack 0xc192e2c0
kernel: supervisor trap page fault, code=0
Stopped in pid 0.0 (system) at  netbsd:hardclock+0x23:  movl    3c(%esi),%eax
db{0}> bt
hardclock(0,0,da3eef6c,c04ac8f1,0,0,0,0,0,0) at netbsd:hardclock+0x23
clockintr(0,0,0,0,0,0,0,0,c2d72000,c010322a) at netbsd:clockintr+0x2a
intr_kdtrace_wrapper(c2f50680,c1930d9c,0,0,0,0,0,0,0,0) at netbsd:intr_kdtrace_wrapper+0x21
--- switch to interrupt stack ---
Xintr_legacy0() at netbsd:Xintr_legacy0+0xda
--- interrupt ---
outb(c16230c0,c1620f80,0,20,1,0,0,c16c2a80,c1930e94,0) at netbsd:outb+0x9
intr_establish_xname(0,c16230c0,0,1,7,c04c96c5,0,0,c134e6d0,0) at netbsd:intr_establish_xname+0x2ba
isa_intr_establish_xname(0,0,1,7,c04c96c5,0,c134e6d0,c1930f14,c04c9bbf,0) at netbsd:isa_intr_establish_xname+0x91
isa_intr_establish(0,0,1,7,c04c96c5,0,c1930f60,c0d3d1ca,c04b6858,1000) at netbsd:isa_intr_establish+0x3c
i8254_initclocks(c04b6858,1000,3,c11b01f0,db0bc000,db0bb000,c166db40,0,c1930f60,c0e5f3f7) at netbsd:i8254_initclocks+0x3a
initclocks(3,5,64,0,0,0,0,0,16800000,0) at netbsd:initclocks+0x1c
main(0,0,0,0,0,0,0,0,0,0) at netbsd:main+0x365

-uwe