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kernel BUG at /build/buildd/linux-2.6.31/lib/prio_tree.c:149!
invalid opcode: 0000 [#1] SMP 
last sysfs file: /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/ieee80211/phy0/rfkill0/uevent
CPU 0 
Modules linked in: cryptd aes_x86_64 aes_generic binfmt_misc ppdev dm_crypt snd_hda_codec_si3054 arc4 ecb snd_hda_codec_idt iwl3945 snd_hda_intel iwlcore snd_hda_codec joydev pcmcia mac80211 iptable_filter ip_tables x_tables led_class snd_pcm_oss snd_mixer_oss yenta_socket snd_pcm rsrc_nonstatic psmouse tifm_7xx1 snd_seq_dummy cfg80211 pcmcia_core serio_raw tifm_core snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq lp snd_timer parport snd_seq_device snd soundcore snd_page_alloc fbcon tileblit font bitblit softcursor i915 drm i2c_algo_bit ohci1394 usbhid sky2 intel_agp ieee1394 video output
Pid: 1224, comm: Xorg Not tainted 2.6.31-11-generic #38-Ubuntu MX6931                          
RIP: 0010:[<ffffffff81270d35>]  [<ffffffff81270d35>] prio_tree_replace+0x75/0x80
RSP: 0018:ffff880066dc7db8  EFLAGS: 00010282
RAX: ffff8800591f01a8 RBX: ffff88007a000848 RCX: ffff88007a8e1e08
RDX: ffff88001d5369e8 RSI: ffff8800591f01a8 RDI: ffff88007a000848
RBP: ffff880066dc7db8 R08: 0000000000000000 R09: 0000000000000000
R10: ffff88001ec9a870 R11: 0000000000000000 R12: ffff8800591f01a8
R13: ffff88007c18dd80 R14: ffff88007a000828 R15: 00007f4fdf298000
FS:  00007f4fdf3d26f0(0000) GS:ffff8800019eb000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f53b9038 CR3: 0000000066da7000 CR4: 00000000000006b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process Xorg (pid: 1224, threadinfo ffff880066dc6000, task ffff880066d1dac0)
Stack:
 ffff880066dc7dd8 ffffffff81270dff 0000000000000000 ffff8800591f0160
<0> ffff880066dc7df8 ffffffff810e9670 ffff88007a000868 ffff8800591f0160
<0> ffff880066dc7e08 ffffffff810f5fcc ffff880066dc7e38 ffffffff810f603b
Call Trace:
 [<ffffffff81270dff>] prio_tree_remove+0xbf/0xf0
 [<ffffffff810e9670>] vma_prio_tree_remove+0x80/0x110
 [<ffffffff810f5fcc>] __remove_shared_vm_struct+0x3c/0x60
 [<ffffffff810f603b>] unlink_file_vma+0x4b/0x70
 [<ffffffff810f0588>] free_pgtables+0x48/0x110
 [<ffffffff810f7604>] unmap_region+0x104/0x160
 [<ffffffff810f7bde>] do_munmap+0x26e/0x350
 [<ffffffff810f7d11>] sys_munmap+0x51/0x80
 [<ffffffff81011fc2>] system_call_fastpath+0x16/0x1b
Code: 46 08 48 89 50 10 48 89 f0 c9 c3 0f 1f 00 48 3b 37 75 18 48 89 52 10 48 89 17 eb c3 66 2e 0f 1f 84 00 00 00 00 00 48 89 10 eb b4 <0f> 0b eb fe 0f 1f 80 00 00 00 00 55 48 89 f0 48 89 e5 41 54 49 
RIP  [<ffffffff81270d35>] prio_tree_replace+0x75/0x80
 RSP <ffff880066dc7db8>
---[ end trace eda2b584b7ac7e43 ]---