Panic with "Unrecoverable machine check exception"

Never seen this type of panic.  I can upload 
core.txt.4 and info.4 to freefall if someone
wants more details.


__curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:57
57		__asm("movq %%gs:%c1,%0" : "=r" (td)
(kgdb) #0  __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:57
        td = <optimized out>
#1  doadump (textdump=textdump@entry=1)
    at /usr/src/sys/kern/kern_shutdown.c:399
        error = 0
        coredump = <optimized out>
#2  0xffffffff80676e30 in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:519
        once = 0
        __pc = 0x0
#3  0xffffffff80677367 in vpanic (
    fmt=0xffffffff80abdb94 "Unrecoverable machine check exception", 
    ap=ap@entry=0xfffffe001c024ed0) at /usr/src/sys/kern/kern_shutdown.c:974
        buf = "Unrecoverable machine check exception", '\000' <repeats 218 times>
        __pc = 0x0
        __pc = 0x0
        __pc = 0x0
        other_cpus = {__bits = {251, 0 <repeats 15 times>}}
        td = 0xfffff80004601000
        bootopt = <unavailable>
        newpanic = <optimized out>
#4  0xffffffff80677193 in panic (fmt=<unavailable>)
    at /usr/src/sys/kern/kern_shutdown.c:887
        ap = {{gp_offset = 8, fp_offset = 48, 
            overflow_arg_area = 0xfffffe001c024f00, 
            reg_save_area = 0xfffffe001c024ea0}}
#5  0xffffffff809d391b in mca_intr () at /usr/src/sys/x86/x86/mca.c:1540
        recoverable = false
        mcg_status = <optimized out>
        count = <optimized out>
        lmcs = <optimized out>
#6  <signal handler called>
No locals.
#7  mi_switch (flags=flags@entry=262) at /usr/src/sys/kern/kern_synch.c:537
        __pc = 0x0
        __pc = 0x0
        __pc = 0x0
        __pc = 0x0
        __pc = 0x0
        td = 0xfffff80004601000
        new_switchtime = <optimized out>
        runtime = <optimized out>
#8  0xffffffff806aaca4 in sched_idletd (dummy=dummy@entry=0x0)
    at /usr/src/sys/kern/sched_4bsd.c:1688
        __pc = 0x0
        stat = <optimized out>
#9  0xffffffff806324b2 in fork_exit (
    callout=0xffffffff806aac50 <sched_idletd>, arg=0x0, 
    frame=0xfffffe00d5407f40) at /usr/src/sys/kern/kern_fork.c:1153
        __pc = 0x0
        __pc = 0x0
        td = 0xfffff80004601000
        p = 0xfffffe00c3002040
        dtd = <optimized out>
#10 <signal handler called>






-- 
Steve