kernel BUG at kernel/exit.c:855!

[David L. Crow]

I woke up this morning and my machine was frozen and I had to perform a
poweroff to reset it.

The following information was in my syslog:

   Sep  8 04:05:19 waterloo kernel: ------------[ cut here ]------------
   Sep  8 04:05:19 waterloo kernel: kernel BUG at kernel/exit.c:855!
   Sep  8 04:05:19 waterloo kernel: invalid operand: 0000 [#1]
   Sep  8 04:05:19 waterloo kernel: SMP
   Sep  8 04:05:19 waterloo kernel: Modules linked in: nls_utf8 vfat fat usb_storage udf tuner tvaudio msp3400 bttv video_buf i2c_algo_bit v4l2_common btcx_risc i2c_core videodev sr_mod snd_pcm_oss ppp_deflate zlib_deflate bsd_comp(U) ppp_async crc_ccitt ppp_generic(U) slhc snd_es1938 snd_pcm snd_page_alloc snd_opl3_lib snd_timer snd_hwdep gameport snd_mpu401_uart snd_rawmidi snd_seq_device snd_mixer_oss snd soundcore vmnet(U) vmmon(U) parport_pc lp parport autofs4 sunrpc ipt_LOG ipt_state ipt_multiport ipt_MASQUERADE ip_nat_tftp ip_nat_snmp_basic ip_nat_irc ip_nat_ftp ip_nat_amanda iptable_nat ip_conntrack_tftp ip_conntrack_irc ip_conntrack_ftp ip_conntrack_amanda ip_conntrack iptable_filter ip_tables 3c59x e100 mii floppy sg microcode dm_mod joydev uhci_hcd ehci_hcd button battery asus_acpi ac md5 ipv6 ext3 jbd ata_piix libata sd_mod scsi_mod
   Sep  8 04:05:19 waterloo kernel: CPU:    0
   Sep  8 04:05:20 waterloo kernel: EIP:    0060:[<02123b4d>]    Tainted: P
   Sep  8 04:05:20 waterloo kernel: EFLAGS: 00010246   (2.6.8-1.521smp)

I'm looking for help to figure out what caused this.

I looked at the exit.c source and it is not immediately obvious to me as
a kernel novice which of the functions in this function should not
return so that the BUG() line is not normally executed.
-- 
  David L. Crow                     Texas!  It's like a
  crow at OrangeBlood.org              whole other country.