Kernel panic. Unsure of cause.

[Charlie Turner]

I had just closed Firefox 3 and went to open the Thunar file manager
from XFCE and my machine locked up. After ~20 seconds, it rebooted,
leaving a 310MB vmcore.0 in /var/crash along with a bounds and info.0
file.

I have no idea how to investigate these problems, so please excuse the
ignorance that may follow:

I followed a section in the FreeBSD Developers Handbook on debugging
the kernel, the following means absolutely nothing to me:

newton# kgdb /boot/kernel/kernel /var/crash/vmcore.0
[GDB will not be able to debug user-mode threads:
/usr/lib/libthread_db.so: Undefined symbol "ps_pglobal_lookup"]
GNU gdb 6.1.1 [FreeBSD]
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i386-marcel-freebsd".

Unread portion of the kernel message buffer:
kernel trap 12 with interrupts disabled


Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address   = 0x18
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0xc0785825
stack pointer           = 0x28:0xe929ba58
frame pointer           = 0x28:0xe929ba74
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = resume, IOPL = 0
current process         = 1072 (Thunar)
trap number             = 12
panic: page fault
cpuid = 1
Uptime: 7h35m34s
Physical memory: 3058 MB
Dumping 310 MB: 295 279 263 247 231 215 199 183 167 151 135 119 103 87
71 55 39 23 7

#0  doadump () at pcpu.h:195
195     pcpu.h: No such file or directory.
        in pcpu.h
(kgdb) backtrace
#0  doadump () at pcpu.h:195
#1  0xc0754457 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:409
#2  0xc0754719 in panic (fmt=Variable "fmt" is not available.
) at /usr/src/sys/kern/kern_shutdown.c:563
#3  0xc0a4905c in trap_fatal (frame=0xe929ba18, eva=24)
    at /usr/src/sys/i386/i386/trap.c:899
#4  0xc0a499df in trap (frame=0xe929ba18) at /usr/src/sys/i386/i386/trap.c:280
#5  0xc0a2fc0b in calltrap () at /usr/src/sys/i386/i386/exception.s:139
#6  0xc0785825 in turnstile_broadcast (ts=0x0, queue=0)
    at /usr/src/sys/kern/subr_turnstile.c:835
#7  0xc0747da2 in _mtx_unlock_sleep (m=0xc81c60a0, opts=0, file=0x0, line=0)
    at /usr/src/sys/kern/kern_mutex.c:605
#8  0xc06fdbd1 in pfs_getextattr (va=0xe929bafc) at pseudofs_internal.h:110
#9  0xc0a5e667 in VOP_GETEXTATTR_APV (vop=0xc0b723e0, a=0xe929bafc)
    at vnode_if.c:2398
#10 0xc07c047e in extattr_get_vp (vp=0xc8fbdaa0, attrnamespace=1,
    attrname=0xe929bb71 "mime_type", data=0x0, nbytes=0, td=0xccc81c60)
    at vnode_if.h:1289
#11 0xc07c0916 in extattr_get_fd (td=0xccc81c60, uap=0xe929bcfc)
    at /usr/src/sys/kern/vfs_extattr.c:408
#12 0xc0a49635 in syscall (frame=0xe929bd38)
    at /usr/src/sys/i386/i386/trap.c:1035
#13 0xc0a2fc70 in Xint0x80_syscall () at /usr/src/sys/i386/i386/exception.s:196
#14 0x00000033 in ?? ()
Previous frame inner to this frame (corrupt stack?)
(kgdb)


Contents of bound and info,0 files in /var/crash (vmcore.0 is too big
for me to put on the Internet)

bounds:

newton# cat bounds
1

info.0:

newton# cat info.0
Dump header from device /dev/ad6s2b
  Architecture: i386
  Architecture Version: 2
  Dump Length: 326086656B (310 MB)
  Blocksize: 512
  Dumptime: Sun Feb 15 18:14:51 2009
  Hostname: newton.turnerfrontier.net
  Magic: FreeBSD Kernel Dump
  Version String: FreeBSD 7.0-RELEASE #0: Sun Feb 24 19:59:52 UTC 2008
    root at logan.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC
  Panic String: page fault
  Dump Parity: 3822966285
  Bounds: 0
  Dump Status: good

Some information from the output of dmesg:

FreeBSD 7.0-RELEASE #0
CPU: Intel(R) Core(TM)2 Duo CPU     E8400  @ 3.00GHz (2999.96-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x10676  Stepping = 6
  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=0x8e3fd<SSE3,RSVD2,MON,DS_CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,<b19>>
  AMD Features=0x20100000<NX,LM>
  AMD Features2=0x1<LAHF>
  Cores per package: 2
real memory  = 3220701184 (3071 MB)
avail memory = 3146219520 (3000 MB)

I'm also using an nVidia 9500GT with 512MB of on-board memory:
vgapci0: <VGA-compatible display> port 0xac00-0xac7f mem
0xfd000000-0xfdffffff,0xc0000000-0xdfffffff,0xfa000000-0xfbffffff irq
16 at device 0.0 on pci1

Thank you for reading this. If there is anything further I can do to
investigate this I would appreciate you telling me so. I haven't
noticed any problems with the hardware recently, and the computer is
fairly new.

--
Charlie Turner.