------------[ cut here ]------------
WARNING: at /build/buildd/linux-2.6.38/drivers/gpu/drm/radeon/radeon_fence.c:248 radeon_fence_wait+0x36f/0x3e0 [radeon]()
Hardware name: Aspire 7551                    
GPU lockup (waiting for 0x000000B1 last fence id 0x000000AE)
Modules linked in: xt_limit xt_tcpudp ipt_LOG ipt_MASQUERADE xt_DSCP ipt_REJECT nf_conntrack_irc nf_conntrack_ftp xt_state binfmt_misc vboxnetadp vboxnetflt vboxdrv snd_hda_codec_hdmi joydev vmnet ppdev parport_pc snd_hda_codec_realtek vmblock vsock vmci vmmon arc4 snd_hda_intel snd_hda_codec snd_hwdep ath9k snd_pcm uvcvideo snd_seq_midi radeon snd_rawmidi mac80211 videodev v4l2_compat_ioctl32 snd_seq_midi_event snd_seq ttm ath9k_common iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 drm_kms_helper iptable_mangle iptable_filter snd_timer snd_seq_device ip_tables x_tables snd ath9k_hw drm psmouse ath edac_core serio_raw i2c_algo_bit soundcore snd_page_alloc k10temp cfg80211 sp5100_tco shpchp edac_mce_amd i2c_piix4 video lp parport ahci tg3 libahci
Pid: 1446, comm: Xorg Tainted: G        W   2.6.38-8-generic #42-Ubuntu
Call Trace:
 [<ffffffff81065cef>] ? warn_slowpath_common+0x7f/0xc0
 [<ffffffff81065de6>] ? warn_slowpath_fmt+0x46/0x50
 [<ffffffffa02f56df>] ? radeon_fence_wait+0x36f/0x3e0 [radeon]
 [<ffffffff81087f30>] ? autoremove_wake_function+0x0/0x40
 [<ffffffffa02f5fc1>] ? radeon_sync_obj_wait+0x11/0x20 [radeon]
 [<ffffffffa0225b0d>] ? ttm_bo_wait+0xfd/0x1b0 [ttm]
 [<ffffffffa0225e88>] ? ttm_bo_list_ref_sub+0x28/0x30 [ttm]
 [<ffffffffa030e9e3>] ? radeon_gem_wait_idle_ioctl+0x93/0x110 [radeon]
 [<ffffffffa0106384>] ? drm_ioctl+0x3e4/0x4c0 [drm]
 [<ffffffffa030e950>] ? radeon_gem_wait_idle_ioctl+0x0/0x110 [radeon]
 [<ffffffff8100b7b1>] ? handle_signal+0x131/0x260
 [<ffffffff810156d1>] ? fpu_finit+0x21/0x40
 [<ffffffff810157fa>] ? init_fpu+0x4a/0x150
 [<ffffffff8117648f>] ? do_vfs_ioctl+0x8f/0x360
 [<ffffffff8100bd06>] ? sys_rt_sigreturn+0x106/0x140
 [<ffffffff811767f1>] ? sys_ioctl+0x91/0xa0
 [<ffffffff8100c002>] ? system_call_fastpath+0x16/0x1b
---[ end trace 5a5d197966b56a30 ]---