kernel core dump hangs with the SMP kernel (FreeBSD 6.2)

Yong Rao yrao at
Wed Jun 20 23:52:06 UTC 2007


I am able to isolate the problem to kernel configurations which
have SMP enabled when used with 2 cpus. With ONE cpu the core dump works

I built the kernel with GENERIC, and deliberately crash the kernel (for
testing purpose). The core dump works fine.
Only added the "options SMP" and crashed the kernel, then prior to any
pages being dumped out, it hangs there.

Has someone successfully core dumped on a system using SMP kernel with
multiple CPUs?

I tried on two different boxes (different motherboards, CPUs and hard
disks). Both got failed.

I tried to enable the DDB, but don't know what to look for when it goes
into ddb. Appreciate any pointers.

a) The CPU information is 

CPU: Dual Core AMD Opteron(tm) Processor 280 (2405.47-MHz 686-class CPU)
  Origin = "AuthenticAMD"  Id = 0x20f12  Stepping = 2
  AMD Features=0xe2500800<SYSCALL,NX,MMX+,FFXSR,LM,3DNow+,3DNow>
  AMD Features2=0x3<LAHF,CMP>
  Cores per package: 2

b) We also tried on another mother board, which has 2 CPUs. The CPU
information is below.

CPU: Intel(R) Xeon(TM) CPU 2.80GHz (2800.11-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf29  Stepping = 9
real memory  = 2147418112 (2047 MB)
avail memory = 2096300032 (1999 MB)
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
 cpu0 (BSP): APIC ID:  0
 cpu1 (AP): APIC ID:  6

c) The following are the prints when the dump hung.

mem dump: start address = 0x4352, len=0x30



Fatal trap 12: page fault while in kernel mode

cpuid = 1; apic id = 01

fault virtual address   = 0x4352

fault code              = supervisor read, page not present

instruction pointer     = 0x20:0xc9e9fc92

stack pointer           = 0x28:0xebdbdbdc

frame pointer           = 0x28:0xebdbdbf8

code segment            = base 0x0, limit 0xfffff, type 0x1b

                        = DPL 0, pres 1, def32 1, gran 1

processor eflags        = interrupt enabled, resume, IOPL = 0

current process         = 74231 (pnicdbg)

trap number             = 12

panic: page fault

cpuid = 1

Uptime: 1d18h27m42s

Dumping 4030 MB (2 chunks)

  chunk 0: 1MB (154 pages) ... ok

  chunk 1: 4031MB (1031776 pages)   (stopped and hung here)



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