spontaneous reboot - ptrace

[Dr. Baud]

    I've an interesting anomaly I'd appreciate some help with.

As a result of looking at a threading problem I modified gcore 
to dump all memory segments associated with a process;
basically comment out the "Ignore" conditional in readmap().
    The result is that the box spontaneously reboots sometime
Between 40 and 50 seconds into the dump; this is an application
that is indeed a memory hog. I commented out the actual
write to disk and the result is the same. I’ve even disabled the
watchdog to no avail.

    This is a vanilla 8.1 install:

FreeBSD pollyanna 8.1-RELEASE FreeBSD 8.1-RELEASE #0: Mon Jul 19 02:36:49 UTC 
2010
     root at mason.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  amd64

    running on fairly vanilla hardware:

CPU: Intel(R) Xeon(TM) CPU 3.20GHz (3212.93-MHz K8-class CPU)
  Origin = "GenuineIntel"  Id = 0xf49  Family = f  Model = 4  Stepping = 9
  Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,C
MOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0x641d<SSE3,DTES64,MON,DS_CPL,CNXT-ID,CX16,xTPR>
  AMD Features=0x20000800<SYSCALL,LM>
  AMD Features2=0x1<LAHF>
  TSC: P-state invariant

 
    Any thoughts on how to proceed?
 
    Dr.