Comment 11 for bug 518034

stacktrace from /var/log/messages on each hang
Mar 1 23:04:40 ws3933 kernel: [ 1319.735024] plymouthd D 00004b46 0 301 1 0x00000000
Mar 1 23:04:40 ws3933 kernel: [ 1319.735029] f64f3e1c 00000086 00000001 00004b46 00000000 c087a6e0 f6a202ac c087a6e0
Mar 1 23:04:40 ws3933 kernel: [ 1319.735036] c6a02301 00000003 c087a6e0 c087a6e0 f6a202ac c087a6e0 c087a6e0 f643c8c0
Mar 1 23:04:40 ws3933 kernel: [ 1319.735042] c689de23 00000003 f6a20000 f698f414 f698f418 ffffffff f64f3e48 c05a40b6
Mar 1 23:04:40 ws3933 kernel: [ 1319.735048] Call Trace:
Mar 1 23:04:40 ws3933 kernel: [ 1319.735057] [<c05a40b6>] __mutex_lock_slowpath+0xc6/0x130
Mar 1 23:04:40 ws3933 kernel: [ 1319.735061] [<c05a3fd5>] mutex_lock+0x25/0x40
Mar 1 23:04:40 ws3933 kernel: [ 1319.735070] [<f8201b54>] nouveau_gem_ioctl_cpu_fini+0x54/0xb0 [lbm_nouveau]
Mar 1 23:04:40 ws3933 kernel: [ 1319.735072] [<c05a513f>] ? _spin_lock_irqsave+0x2f/0x50
Mar 1 23:04:40 ws3933 kernel: [ 1319.735080] [<f807e8cd>] lbm_drm_ioctl+0x25d/0x3e0 [lbm_drm]
Mar 1 23:04:40 ws3933 kernel: [ 1319.735089] [<f8201b00>] ? nouveau_gem_ioctl_cpu_fini+0x0/0xb0 [lbm_nouveau]
Mar 1 23:04:40 ws3933 kernel: [ 1319.735092] [<c01ff5c5>] ? mem_cgroup_update_mapped_file_stat+0x35/0x90
Mar 1 23:04:40 ws3933 kernel: [ 1319.735095] [<c01c7926>] ? unlock_page+0x46/0x50
Mar 1 23:04:40 ws3933 kernel: [ 1319.735097] [<c01e2200>] ? __do_fault+0x3a0/0x490
Mar 1 23:04:40 ws3933 kernel: [ 1319.735100] [<c03b8ac0>] ? vt_ioctl+0x0/0x16a0
Mar 1 23:04:40 ws3933 kernel: [ 1319.735103] [<c03af52c>] ? tty_ioctl+0x7c/0x630
Mar 1 23:04:40 ws3933 kernel: [ 1319.735110] [<f807e670>] ? lbm_drm_ioctl+0x0/0x3e0 [lbm_drm]
Mar 1 23:04:40 ws3933 kernel: [ 1319.735113] [<c02139a1>] vfs_ioctl+0x21/0x90
Mar 1 23:04:40 ws3933 kernel: [ 1319.735116] [<c0213c89>] do_vfs_ioctl+0x79/0x310
Mar 1 23:04:40 ws3933 kernel: [ 1319.735118] [<c05a7662>] ? do_page_fault+0x152/0x380
Mar 1 23:04:40 ws3933 kernel: [ 1319.735121] [<c0213f87>] sys_ioctl+0x67/0x80
Mar 1 23:04:40 ws3933 kernel: [ 1319.735123] [<c01033ec>] syscall_call+0x7/0xb