Moin,
I got this on 3.11-rc1+ when halting the box:
[ 883.476242] ------------[ cut here ]------------ [ 883.480927] WARNING: CPU: 3 PID: 2701 at drivers/gpu/drm/nouveau/nouveau_gem.c:54 nouveau_gem_object_del+0xa8/0xc0() [ 883.491545] Modules linked in: ntfs msdos dm_mod ext2 vfat fat loop fuse usbhid snd_hda_codec_hdmi x86_pkg_temp_thermal coretemp kvm_intel kvm snd_hda_codec_realtek snd_hda_intel snd_hda_codec crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel ehci_pci xhci_hcd iTCO_wdt acpi_cpufreq snd_hwdep aesni_intel ehci_hcd aes_x86_64 mperf glue_helper button snd_pcm i2c_i801 iTCO_vendor_support snd_page_alloc usbcore dcdbas lrw gf128mul processor snd_timer pcspkr sb_edac ablk_helper evdev edac_core usb_common lpc_ich cryptd snd mfd_core soundcore microcode [ 883.542505] CPU: 3 PID: 2701 Comm: Xorg Not tainted 3.11.0-rc1+ #4 [ 883.548746] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 [ 883.556214] 0000000000000009 ffff88043b087ca0 ffffffff815fc47d 0000000000000000 [ 883.563735] ffff88043b087cd8 ffffffff81047e6c ffff8804302a8800 ffff88043c2cc600 [ 883.571252] ffff88043d6da000 0000000000000009 ffff88043b087d70 ffff88043b087ce8 [ 883.578780] Call Trace: [ 883.581265] [<ffffffff815fc47d>] dump_stack+0x54/0x74 [ 883.586463] [<ffffffff81047e6c>] warn_slowpath_common+0x8c/0xc0 [ 883.592523] [<ffffffff81047eba>] warn_slowpath_null+0x1a/0x20 [ 883.598408] [<ffffffff813e6e58>] nouveau_gem_object_del+0xa8/0xc0 [ 883.604657] [<ffffffff8135cd5a>] drm_gem_object_free+0x2a/0x30 [ 883.610630] [<ffffffff8135d008>] drm_gem_object_release_handle+0xa8/0xd0 [ 883.617497] [<ffffffff812947e6>] idr_for_each+0xb6/0x110 [ 883.622952] [<ffffffff8135cf60>] ? drm_gem_vm_close+0x80/0x80 [ 883.628851] [<ffffffff81600ede>] ? mutex_unlock+0xe/0x10 [ 883.634304] [<ffffffff8135dc60>] drm_gem_release+0x20/0x30 [ 883.639933] [<ffffffff8135c01a>] drm_release+0x5ba/0x650 [ 883.645397] [<ffffffff8116271f>] __fput+0xff/0x250 [ 883.650317] [<ffffffff811628be>] ____fput+0xe/0x10 [ 883.655244] [<ffffffff8106c6b5>] task_work_run+0xb5/0xe0 [ 883.660706] [<ffffffff8104da93>] do_exit+0x2b3/0xa40 [ 883.665808] [<ffffffff816049c9>] ? retint_swapgs+0xe/0x13 [ 883.671343] [<ffffffff8104e349>] do_group_exit+0x49/0xc0 [ 883.676803] [<ffffffff8104e3d7>] SyS_exit_group+0x17/0x20 [ 883.682351] [<ffffffff8160d1c6>] system_call_fastpath+0x1a/0x1f [ 883.688418] ---[ end trace 9e774929633864b2 ]--- [ 883.693096] [ 883.694609] ====================================================== [ 883.700852] [ INFO: possible circular locking dependency detected ] [ 883.707204] 3.11.0-rc1+ #4 Tainted: G W [ 883.711955] ------------------------------------------------------- [ 883.718292] Xorg/2701 is trying to acquire lock: [ 883.722969] (reservation_ww_class_mutex){+.+.+.}, at: [<ffffffff813e4cfc>] nouveau_bo_unpin+0x3c/0x120 [ 883.732548] [ 883.732548] but task is already holding lock: [ 883.738446] (&dev->struct_mutex){+.+.+.}, at: [<ffffffff8135cfda>] drm_gem_object_release_handle+0x7a/0xd0 [ 883.748387] [ 883.748387] which lock already depends on the new lock. [ 883.748387] [ 883.756649] [ 883.756649] the existing dependency chain (in reverse order) is: [ 883.764211] -> #1 (&dev->struct_mutex){+.+.+.}: [ 883.769051] [<ffffffff810a61ea>] lock_acquire+0x8a/0x120 [ 883.775066] [<ffffffff815ff485>] mutex_lock_nested+0x75/0x380 [ 883.781516] [<ffffffff813e6cae>] validate_fini_list.isra.7+0xde/0x130 [ 883.788662] [<ffffffff813e6d20>] validate_fini_no_ticket+0x20/0x50 [ 883.795555] [<ffffffff813e6d62>] validate_fini+0x12/0x50 [ 883.801566] [<ffffffff813e7862>] nouveau_gem_ioctl_pushbuf+0x3a2/0x16a0 [ 883.808887] [<ffffffff8135b589>] drm_ioctl+0x559/0x690 [ 883.814721] [<ffffffff81172bf7>] do_vfs_ioctl+0x97/0x590 [ 883.820737] [<ffffffff81173140>] SyS_ioctl+0x50/0x90 [ 883.826382] [<ffffffff8160d1c6>] system_call_fastpath+0x1a/0x1f [ 883.832999] -> #0 (reservation_ww_class_mutex){+.+.+.}: [ 883.838523] [<ffffffff810a5b44>] __lock_acquire+0x1c54/0x1d40 [ 883.844963] [<ffffffff810a61ea>] lock_acquire+0x8a/0x120 [ 883.850965] [<ffffffff815ff485>] mutex_lock_nested+0x75/0x380 [ 883.857401] [<ffffffff813e4cfc>] nouveau_bo_unpin+0x3c/0x120 [ 883.864402] [<ffffffff813e6e45>] nouveau_gem_object_del+0x95/0xc0 [ 883.871831] [<ffffffff8135cd5a>] drm_gem_object_free+0x2a/0x30 [ 883.878998] [<ffffffff8135d008>] drm_gem_object_release_handle+0xa8/0xd0 [ 883.887030] [<ffffffff812947e6>] idr_for_each+0xb6/0x110 [ 883.893659] [<ffffffff8135dc60>] drm_gem_release+0x20/0x30 [ 883.900456] [<ffffffff8135c01a>] drm_release+0x5ba/0x650 [ 883.907060] [<ffffffff8116271f>] __fput+0xff/0x250 [ 883.913113] [<ffffffff811628be>] ____fput+0xe/0x10 [ 883.919163] [<ffffffff8106c6b5>] task_work_run+0xb5/0xe0 [ 883.925738] [<ffffffff8104da93>] do_exit+0x2b3/0xa40 [ 883.931959] [<ffffffff8104e349>] do_group_exit+0x49/0xc0 [ 883.938520] [<ffffffff8104e3d7>] SyS_exit_group+0x17/0x20 [ 883.945170] [<ffffffff8160d1c6>] system_call_fastpath+0x1a/0x1f [ 883.952349] [ 883.952349] other info that might help us debug this: [ 883.952349] [ 883.962128] Possible unsafe locking scenario: [ 883.962128] [ 883.969252] CPU0 CPU1 [ 883.974396] ---- ---- [ 883.979532] lock(&dev->struct_mutex); [ 883.984013] lock(reservation_ww_class_mutex); [ 883.991723] lock(&dev->struct_mutex); [ 883.998725] lock(reservation_ww_class_mutex); [ 884.003888] [ 884.003888] *** DEADLOCK *** [ 884.003888] [ 884.011525] 2 locks held by Xorg/2701: [ 884.015875] #0: (drm_global_mutex){+.+.+.}, at: [<ffffffff8135ba99>] drm_release+0x39/0x650 [ 884.025136] #1: (&dev->struct_mutex){+.+.+.}, at: [<ffffffff8135cfda>] drm_gem_object_release_handle+0x7a/0xd0 [ 884.036057] [ 884.036057] stack backtrace: [ 884.041589] CPU: 7 PID: 2701 Comm: Xorg Tainted: G W 3.11.0-rc1+ #4 [ 884.049362] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A08 01/24/2013 [ 884.057400] ffffffff822efb50 ffff88043b087ab8 ffffffff815fc47d ffffffff822efb50 [ 884.065501] ffff88043b087af8 ffffffff815f90aa ffff88043b087b80 ffff8804399e8600 [ 884.073609] ffff8804399e85d8 0000000000000001 0000000000000002 ffff8804399e8000 [ 884.081717] Call Trace: [ 884.084768] [<ffffffff815fc47d>] dump_stack+0x54/0x74 [ 884.090543] [<ffffffff815f90aa>] print_circular_bug+0x1f9/0x208 [ 884.097187] [<ffffffff810a5b44>] __lock_acquire+0x1c54/0x1d40 [ 884.103652] [<ffffffff8160447c>] ? _raw_spin_unlock_irq+0x2c/0x40 [ 884.110466] [<ffffffff810a6c8d>] ? trace_hardirqs_on_caller+0x10d/0x1d0 [ 884.117809] [<ffffffff8107a655>] ? finish_task_switch+0x85/0x120 [ 884.124529] [<ffffffff810a61ea>] lock_acquire+0x8a/0x120 [ 884.130541] [<ffffffff813e4cfc>] ? nouveau_bo_unpin+0x3c/0x120 [ 884.137079] [<ffffffff815ff485>] mutex_lock_nested+0x75/0x380 [ 884.143530] [<ffffffff813e4cfc>] ? nouveau_bo_unpin+0x3c/0x120 [ 884.150067] [<ffffffff813e4cfc>] nouveau_bo_unpin+0x3c/0x120 [ 884.156418] [<ffffffff813e6e45>] nouveau_gem_object_del+0x95/0xc0 [ 884.163210] [<ffffffff8135cd5a>] drm_gem_object_free+0x2a/0x30 [ 884.169743] [<ffffffff8135d008>] drm_gem_object_release_handle+0xa8/0xd0 [ 884.177149] [<ffffffff812947e6>] idr_for_each+0xb6/0x110 [ 884.183155] [<ffffffff8135cf60>] ? drm_gem_vm_close+0x80/0x80 [ 884.189607] [<ffffffff81600ede>] ? mutex_unlock+0xe/0x10 [ 884.195622] [<ffffffff8135dc60>] drm_gem_release+0x20/0x30 [ 884.201815] [<ffffffff8135c01a>] drm_release+0x5ba/0x650 [ 884.207827] [<ffffffff8116271f>] __fput+0xff/0x250 [ 884.213316] [<ffffffff811628be>] ____fput+0xe/0x10 [ 884.218799] [<ffffffff8106c6b5>] task_work_run+0xb5/0xe0 [ 884.224810] [<ffffffff8104da93>] do_exit+0x2b3/0xa40 [ 884.230470] [<ffffffff816049c9>] ? retint_swapgs+0xe/0x13 [ 884.236571] [<ffffffff8104e349>] do_group_exit+0x49/0xc0 [ 884.242582] [<ffffffff8104e3d7>] SyS_exit_group+0x17/0x20 [ 884.248688] [<ffffffff8160d1c6>] system_call_fastpath+0x1a/0x1f