------------[ cut here ]------------
WARNING: at /build/buildd/linux-2.6.31/fs/buffer.c:1152 mark_buffer_dirty+0x70/0x90()
Hardware name: System Name
Modules linked in: ppp_deflate zlib_deflate bsd_comp ppp_async crc_ccitt option usbserial usb_storage binfmt_misc bridge stp bnep snd_via82xx nfsd exportfs snd_mpu401_uart nfs it87 snd_seq_dummy lockd snd_via82xx_modem snd_usb_audio snd_pcm_oss snd_ac97_codec hwmon_vid ac97_bus snd_mixer_oss nfs_acl snd_seq_oss snd_pcm snd_seq_midi snd_usb_lib snd_hwdep snd_rawmidi iptable_filter auth_rpcgss eeprom snd_seq_midi_event ip_tables ppdev snd_seq lp gspca_zc3xx sunrpc gspca_main snd_timer psmouse ns558 x_tables parport_pc i2c_viapro snd_seq_device nvidia(P) videodev serio_raw snd gameport parport btusb soundcore snd_page_alloc v4l1_compat shpchp joydev raid10 raid456 raid6_pq async_xor async_memcpy async_tx raid1 raid0 multipath linear dm_raid45 xor fbcon tileblit font bitblit softcursor vesafb usbhid floppy sata_via skge via_agp agpgart
Pid: 5552, comm: umount Tainted: P           2.6.31-14-generic #48-Ubuntu
Call Trace:
 [<c014518d>] warn_slowpath_common+0x6d/0xa0
 [<c02093b0>] ? mark_buffer_dirty+0x70/0x90
 [<c02093b0>] ? mark_buffer_dirty+0x70/0x90
 [<c0224ae0>] ? vfs_quota_off+0x0/0x20
 [<c01451d5>] warn_slowpath_null+0x15/0x20
 [<c02093b0>] mark_buffer_dirty+0x70/0x90
 [<c0258e73>] ext2_sync_fs+0x33/0x90
 [<c02072a9>] __sync_filesystem+0x39/0x60
 [<c0207471>] sync_filesystem+0x31/0x50
 [<c01e9452>] generic_shutdown_super+0x22/0xd0
 [<c01e9525>] kill_block_super+0x25/0x40
 [<c01ea1fe>] deactivate_super+0x5e/0x90
 [<c01fd8f7>] mntput_no_expire+0x87/0xd0
 [<c01fded2>] sys_umount+0x42/0x90
 [<c010336c>] syscall_call+0x7/0xb
---[ end trace d0c7af26c9e0a454 ]---