Complete hang on 9.0-RELEASE

[Arnaud Lacombe]

Hi folks,

For the records, I was running some tests yesterday on top of a
9.0-RELEASE, amd64, kernel when the box hanged. At the time of the
hang, the box was running a process with about 2800 threads with heavy
IPC between 1400 writers and 1400 readers. The box was in single user
mode (/bin/sh coming from FreeBSD 7.4-STABLE). Here is the beginning
of the dmesg:

Copyright (c) 1992-2012 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 9.0-RELEASE #0: Tue Jan  3 07:46:30 UTC 2012
    root at farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64
CPU: Intel(R) Atom(TM) CPU D510   @ 1.66GHz (1666.70-MHz K8-class CPU)
  Origin = "GenuineIntel"  Id = 0x106ca  Family = 6  Model = 1c  Stepping = 10
  Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
  Features2=0x40e31d<SSE3,DTES64,MON,DS_CPL,TM2,SSSE3,CX16,xTPR,PDCM,MOVBE>
  AMD Features=0x20000800<SYSCALL,LM>
  AMD Features2=0x1<LAHF>
  TSC: P-state invariant, performance statistics
real memory  = 2137587712 (2038 MB)
avail memory = 2037841920 (1943 MB)
Event timer "LAPIC" quality 400
ACPI APIC Table: <070611 APIC1125>
FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
FreeBSD/SMP: 1 package(s) x 2 core(s) x 2 HTT threads
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP/HT): APIC ID:  1
 cpu2 (AP): APIC ID:  2
 cpu3 (AP/HT): APIC ID:  3

I will restart the test and see if this happens again.

regards,
 - Arnaud