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User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.7.6) Gecko/20050328 Firefox/1.0.2 Fedora/1.0.2-3

Description of problem:
I don't know what causes this, but I have seen it twice now.  Running along just fine, I get this message printing on every terminal:

kernel: invalid operand: 0000 [1] SMP

I check dmesg and it has:

----------- [cut here ] --------- [please bite here ] ---------
Kernel BUG at spinlock:121
invalid operand: 0000 [1] SMP
CPU 0
Modules linked in: loop nvidia(U) nfsd md5 ipv6 parport_pc lp parport autofs4 nfs lockd rfcomm l2cap bluetooth pcmcia yenta_socket rsrc_nonstatic pcmcia_core sunrpc ext3 jbd dm_mod video button battery ac ohci1394 ieee1394 ohci_hcd ehci_hcd tpm_nsc tpm i2c_amd8111 i2c_core hw_random snd_intel8x0 snd_ac97_codec snd_pcm_oss snd_mixer_oss snd_pcm snd_timer snd soundcore snd_page_alloc tg3 xfs exportfs aic79xx sd_mod scsi_mod
Pid: 20488, comm: objdump Tainted: P      2.6.11-1.1238_FC4smp
RIP: 0010:[<ffffffff8035f990>] <ffffffff8035f990>{_spin_lock+32}
RSP: 0000:ffff8100113cdd58  EFLAGS: 00010296
RAX: 0000000000000019 RBX: ffffffff804d5a44 RCX: ffffffff8042f508
RDX: ffffffff8042f508 RSI: 0000000000000292 RDI: ffffffff8042f500
RBP: 0000000000000600 R08: ffff810037c9edb8 R09: 0000000000000034
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000008 R14: ffffffff804d5a40 R15: ffffffff804d5a44
FS:  00002aaaaaadcee0(0000) GS:ffffffff80504c80(0000) knlGS:00000000f7fc46c0
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000401c28 CR3: 0000000029b6d000 CR4: 00000000000006e0
Process objdump (pid: 20488, threadinfo ffff8100113cc000, task ffff81005b670170)Stack: 000000003ac6e008 ffffffff8017ee7c ffff810031693090 0000000000401c28
       ffff8100135fcc88 ffff81007f6487a8 600000003ac6e00a ffff81000e98f010
       0000000000000001 ffffffff80173d44
Call Trace:<ffffffff8017ee7c>{valid_swaphandles+124} <ffffffff80173d44>{swapin_readahead+68}
       <ffffffff80175f7c>{handle_mm_fault+620} <ffffffff801239e4>{do_page_fault+1316}
       <ffffffff8017a4bd>{do_mmap_pgoff+1709} <ffffffff8010f599>{error_exit+0}


Code: 0f 0b f3 c9 37 80 ff ff ff ff 79 00 f0 fe 0b 0f 88 ac 04 00
RIP <ffffffff8035f990>{_spin_lock+32} RSP <ffff8100113cdd58>
 <3>Debug: sleeping function called from invalid context at include/linux/rwsem.h:43
in_atomic():0, irqs_disabled():1

Call Trace:<ffffffff8013a875>{profile_task_exit+21} <ffffffff8013bc82>{do_exit+34}
       <ffffffff80260739>{do_unblank_screen+137} <ffffffff801106ad>{die+77}
       <ffffffff80111303>{do_invalid_op+163} <ffffffff8035f990>{_spin_lock+32}
       <ffffffff8010f599>{error_exit+0} <ffffffff8035f990>{_spin_lock+32}
       <ffffffff8035f990>{_spin_lock+32} <ffffffff8017ee7c>{valid_swaphandles+124}
       <ffffffff80173d44>{swapin_readahead+68} <ffffffff80175f7c>{handle_mm_fault+620}
       <ffffffff801239e4>{do_page_fault+1316} <ffffffff8017a4bd>{do_mmap_pgoff+1709}
       <ffffffff8010f599>{error_exit+0}
swap_free: Bad swap file entry 600000003ac6e00a
swap_free: Bad swap offset entry 7fffff802e
swap_free: Bad swap offset entry 800007fffff802e
swap_free: Bad swap file entry 1000007fffff802e
swap_free: Bad swap file entry 1800007fffff802e
swap_free: Bad swap file entry 2000007fffff802e
swap_free: Bad swap file entry 2800007fffff802e
swap_free: Bad swap file entry 3000007fffff802e
swap_free: Bad swap file entry 3800007fffff802e
swap_free: Bad swap file entry 4000007fffff802e
swap_free: Bad swap file entry 4800007fffff802e
swap_free: Bad swap file entry 5000007fffff802e
swap_free: Bad swap file entry 5800007fffff802e
swap_free: Bad swap file entry 6000007fffff802e
swap_free: Bad swap file entry 6800007fffff802e
swap_free: Bad swap file entry 7000007fffff802e
swap_free: Bad swap file entry 7800007fffff802e
swap_free: Bad swap file entry 8000007fffff802e
swap_free: Bad swap file entry 8800007fffff802e
swap_free: Bad swap file entry 9000007fffff802e
swap_free: Bad swap file entry 9800007fffff802e
swap_free: Bad swap file entry a000007fffff802e
swap_free: Bad swap file entry a800007fffff802e
swap_free: Bad swap file entry b000007fffff802e
swap_free: Bad swap file entry b800007fffff802e
swap_free: Bad swap file entry c000007fffff802e
swap_free: Bad swap file entry c800007fffff802e
swap_free: Bad swap file entry d000007fffff802e


Version-Release number of selected component (if applicable):
kernel-smp-2.6.11-1.1238_FC4

How reproducible:
Sometimes

Steps to Reproduce:
1. not sure
2.
3.
  

Additional info: