Fatal trap 28 while building world

Hi,
while trying to follow the recent advice of cvsuping and rebuilding 
world to correct some vm related bug, I got a Fatal trap 28.

The machine was running with sources from about may 1.  Rebuilding now 
to see if the machine can make it through the build.


Fatal trap 28: machine check trap while in kernel mode
cpuid = 1; lapic.id = 01000000
instruction pointer     = 0x8:0xc0296381
stack pointer           = 0x10:0xdbb369dc
frame pointer           = 0x10:0xdbb36ae0
code segment            = base 0x0, limit 0xfffff, type 0x1b
                         = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, IOPL = 0
current process         = 19265 (make)
kernel: type 28 trap, code=0
Stopped at      vn_open_cred+0x2c1:     jz      vn_open_cred+0x2cd
db> trace
vn_open_cred(dbb36bd8,dbb36cd8,1a4,c58e0480,dbb36cc4) at vn_open_cred+0x2c1
vn_open(dbb36bd8,dbb36cd8,1a4,2ab,c0482620) at vn_open+0x29
kern_open(c400ed10,80a01c0,0,1,1b6) at kern_open+0x13d
open(c400ed10,dbb36d10,c041282e,3fb,3) at open+0x30
syscall(2f,2f,2f,80a7500,4) at syscall+0x26e
Xint0x80_syscall() at Xint0x80_syscall+0x1d
--- syscall (5, FreeBSD ELF32, open), eip = 0x8061a9f, esp = 0xbfbfe788, 
ebp = 0
xbfbfe7b4 ---
db>


-- Trond