With Linus' latest tree as of this morning, I see the following backtrace on an Intel NUC with a Celeron processor:

[    3.753631] input: Video Bus as /devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/LNXVIDEO:00/input/input6
[    3.757264] [drm] Initialized i915 1.6.0 20150130 for 0000:00:02.0 on minor 0
[    3.757778] ------------[ cut here ]------------
[    3.757817] WARNING: CPU: 0 PID: 57 at drivers/gpu/drm/i915/i915_gem.c:4525 i915_gem_free_object+0x3b6/0x4a0 [i915]()
[    3.757820] WARN_ON(obj->frontbuffer_bits)
[    3.757834] Modules linked in: i915 i2c_algo_bit drm_kms_helper drm video sdhci_acpi sdhci mmc_core
[    3.757838] CPU: 0 PID: 57 Comm: kworker/u4:2 Not tainted 3.20.0-0.rc0.git7.1.fc23.x86_64 #1
[    3.757840] Hardware name: \xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff \xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff\xffffffff/DN2820FYK, BIOS FYBYT10H.86A.0034.2014.0513.1413 05/13/2014
[    3.757847] Workqueue: events_unbound async_run_entry_fn
[    3.757853]  0000000000000000 00000000122bcbf6 ffff880233227728 ffffffff81876738
[    3.757858]  0000000000000000 ffff880233227780 ffff880233227768 ffffffff810ab5da
[    3.757863]  ffff880236c01700 ffff88003f5a7c80 ffff88003f5a7c00 ffff88003f5a7d00
[    3.757865] Call Trace:
[    3.757871]  [<ffffffff81876738>] dump_stack+0x4c/0x65
[    3.757876]  [<ffffffff810ab5da>] warn_slowpath_common+0x8a/0xc0
[    3.757880]  [<ffffffff810ab665>] warn_slowpath_fmt+0x55/0x70
[    3.757908]  [<ffffffffa0110a7e>] ? i915_vma_unbind+0x32e/0x3f0 [i915]
[    3.757935]  [<ffffffffa01126b6>] i915_gem_free_object+0x3b6/0x4a0 [i915]
[    3.757951]  [<ffffffffa00915c7>] drm_gem_object_free+0x27/0x40 [drm]
[    3.757982]  [<ffffffffa014cd65>] intel_user_framebuffer_destroy+0x75/0xa0 [i915]
[    3.757996]  [<ffffffffa009d4e0>] drm_framebuffer_free+0x50/0x60 [drm]
[    3.758009]  [<ffffffffa009e945>] drm_framebuffer_unreference+0x35/0x70 [drm]
[    3.758023]  [<ffffffffa009ea60>] drm_mode_set_config_internal+0xe0/0x120 [drm]
[    3.758032]  [<ffffffffa005e7d8>] restore_fbdev_mode+0xc8/0xf0 [drm_kms_helper]
[    3.758041]  [<ffffffffa0060849>] drm_fb_helper_restore_fbdev_mode_unlocked+0x29/0x80 [drm_kms_helper]
[    3.758048]  [<ffffffffa00608c2>] drm_fb_helper_set_par+0x22/0x50 [drm_kms_helper]
[    3.758079]  [<ffffffffa016c25a>] intel_fbdev_set_par+0x1a/0x60 [i915]
[    3.758085]  [<ffffffff8149e518>] fbcon_init+0x588/0x610
[    3.758090]  [<ffffffff8153965c>] visual_init+0xbc/0x120
[    3.758094]  [<ffffffff8153c03e>] do_bind_con_driver+0x17e/0x3c0
[    3.758098]  [<ffffffff8153c7e4>] do_take_over_console+0xb4/0x1b0
[    3.758103]  [<ffffffff81499313>] do_fbcon_takeover+0x63/0xd0
[    3.758106]  [<ffffffff8149f06d>] fbcon_event_notify+0x6dd/0x7e0
[    3.758111]  [<ffffffff810d50f2>] notifier_call_chain+0x62/0x100
[    3.758116]  [<ffffffff810d53a1>] __blocking_notifier_call_chain+0x51/0x70
[    3.758120]  [<ffffffff810d53d6>] blocking_notifier_call_chain+0x16/0x20
[    3.758124]  [<ffffffff814a510b>] fb_notifier_call_chain+0x1b/0x20
[    3.758127]  [<ffffffff814a75c2>] register_framebuffer+0x222/0x370
[    3.758136]  [<ffffffffa0060b54>] drm_fb_helper_initial_config+0x264/0x3c0 [drm_kms_helper]
[    3.758167]  [<ffffffffa016d58b>] intel_fbdev_initial_config+0x1b/0x20 [i915]
[    3.758171]  [<ffffffff810d79da>] async_run_entry_fn+0x4a/0x150
[    3.758175]  [<ffffffff810ccc25>] process_one_work+0x215/0x860
[    3.758178]  [<ffffffff810ccb8e>] ? process_one_work+0x17e/0x860
[    3.758182]  [<ffffffff810cd36b>] ? worker_thread+0xfb/0x490
[    3.758186]  [<ffffffff810cd2db>] worker_thread+0x6b/0x490
[    3.758190]  [<ffffffff810cd270>] ? process_one_work+0x860/0x860
[    3.758193]  [<ffffffff810d378f>] kthread+0x11f/0x140
[    3.758198]  [<ffffffff810e9a05>] ? local_clock+0x25/0x30
[    3.758203]  [<ffffffff810d3670>] ? kthread_create_on_node+0x250/0x250
[    3.758207]  [<ffffffff8188077c>] ret_from_fork+0x7c/0xb0
[    3.758211]  [<ffffffff810d3670>] ? kthread_create_on_node+0x250/0x250
[    3.758214] ---[ end trace 52d7387bdd97e9bd ]---
[    3.806995] Console: switching to colour frame buffer device 128x48
[    3.811526] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
[    3.811529] i915 0000:00:02.0: registered panic notifier