BUG: unable to handle kernel paging request at 21b0001c
IP: [<e624c59f>] drm_ioctl+0x2f/0x3e0 [drm]
*pde = 00000000 
Oops: 0000 [#7] SMP 
last sysfs file: /sys/devices/pci0000:00/0000:00:02.0/boot_vga
Modules linked in: vboxvideo drm agpgart binfmt_misc vboxvfs vboxguest snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device fbcon tileblit ppdev font bitblit softcursor snd parport_pc psmouse serio_raw soundcore lp vga16fb vgastate i2c_piix4 snd_page_alloc parport floppy pcnet32 mii

Pid: 1020, comm: Xorg Tainted: G      D    (2.6.32-17-generic #26-Ubuntu) VirtualBox
EIP: 0060:[<e624c59f>] EFLAGS: 00013202 CPU: 0
EIP is at drm_ioctl+0x2f/0x3e0 [drm]
EAX: 00000080 EBX: 21b00000 ECX: c0246400 EDX: 00000000
ESI: e60a5150 EDI: dfb70080 EBP: df287f50 ESP: df287e80
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
Process Xorg (pid: 1020, ti=df286000 task=dfb5cce0 task.ti=df286000)
Stack:
 00000001 df287f50 00000000 00004de3 df287ecc df287f50 df287ecc df287ebc
<0> c0284481 00004de3 c0246400 00000026 c05a4b20 df2e8e80 df287ecc df287f64
<0> c0207704 00004de3 00000000 c145c6e0 df287f5c 00000000 00000001 ffffffff
Call Trace:
 [<c0284481>] ? ext4_file_write+0x41/0xd0
 [<c0246400>] ? vfs_get_dqinfo+0x90/0xc0
 [<c0207704>] ? do_sync_write+0xc4/0x100
 [<c01676a0>] ? autoremove_wake_function+0x0/0x50
 [<c02f3d94>] ? security_file_permission+0x14/0x20
 [<c021605b>] ? vfs_ioctl+0x7b/0x90
 [<c0246400>] ? vfs_get_dqinfo+0x90/0xc0
 [<c02162e9>] ? do_vfs_ioctl+0x79/0x310
 [<c0207640>] ? do_sync_write+0x0/0x100
 [<c02165e7>] ? sys_ioctl+0x67/0x80
 [<c0246400>] ? vfs_get_dqinfo+0x90/0xc0
 [<c01033ec>] ? syscall_call+0x7/0xb
 [<c0246400>] ? vfs_get_dqinfo+0x90/0xc0
 [<c0246400>] ? vfs_get_dqinfo+0x90/0xc0
Code: 56 53 81 ec c4 00 00 00 0f 1f 44 00 00 89 d7 65 8b 15 14 00 00 00 89 55 f0 31 d2 89 8d 58 ff ff ff 8b 58 70 89 f8 25 ff 00 00 00 <8b> 53 1c 8b b2 28 01 00 00 3e ff 46 2c 3e ff 86 88 00 00 00 8b 
EIP: [<e624c59f>] drm_ioctl+0x2f/0x3e0 [drm] SS:ESP 0068:df287e80
CR2: 0000000021b0001c
---[ end trace 52686e8dceb87f2b ]---