------------[ cut here ]------------
WARNING: at /build/buildd/linux-2.6.31/fs/buffer.c:1152 mark_buffer_dirty+0x70/0x90()
Hardware name: Vostro 1500                     
Modules linked in: nfnetlink_queue nfnetlink nf_conntrack_ipv4 nf_defrag_ipv4 ipt_REJECT xt_tcpudp xt_iprange xt_state nf_conntrack xt_mark xt_NFQUEUE michael_mic arc4 ecb binfmt_misc ppdev vboxnetadp vboxnetflt vboxdrv snd_hda_codec_idt snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm bridge stp bnep snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event b44 ssb mii lib80211_crypt_tkip snd_seq snd_timer snd_seq_device snd soundcore wl(P) sdhci_pci sdhci lib80211 snd_page_alloc btusb ricoh_mmc led_class nvidia(P) dell_wmi joydev iptable_filter dell_laptop dcdbas uvcvideo videodev v4l1_compat psmouse serio_raw ip_tables x_tables lp parport usb_storage ohci1394 ieee1394 intel_agp agpgart video output usbhid
Pid: 31943, 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
 [<c01451d5>] warn_slowpath_null+0x15/0x20
 [<c02093b0>] mark_buffer_dirty+0x70/0x90
 [<c024ba05>] ext3_put_super+0x165/0x240
 [<c01fac2e>] ? invalidate_inodes+0xfe/0x120
 [<c0224ae0>] ? vfs_quota_off+0x0/0x20
 [<c01e9478>] generic_shutdown_super+0x48/0xd0
 [<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 3d340e638504d1d3 ]---