https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_6977/shard-skl10/igt@i915_selftest@mock_vma.html
<6> [175.769812] [IGT] i915_selftest: executing
<6> [175.876941] [IGT] i915_selftest: starting subtest mock_vma
<5> [176.482792] Setting dangerous option mock_selftests - tainting kernel
<6> [176.793104] i915: Performing mock selftests with st_random_seed=0xc8486f6 st_timeout=1000
<6> [176.793131] i915: Running vma
<7> [176.808975]  mock: [drm:intel_uc_init_early [i915]] enable_guc=0 (guc:no submission:no huc:no)
<7> [176.821675] [drm:intel_engines_driver_register [i915]] renamed mock to rcs0
<6> [176.828858] i915: Running i915_vma_mock_selftests/igt_vma_create
<7> [177.836614] igt_vma_create timed out: after 2 objects in 673 contexts
<6> [177.856652] i915: Running i915_vma_mock_selftests/igt_vma_pin1
<6> [177.858834] i915: Running i915_vma_mock_selftests/igt_vma_rotate_remap
<6> [212.605198] i915: Running i915_vma_mock_selftests/igt_vma_partial
<3> [248.622185] INFO: task kworker/u8:1:41 blocked for more than 61 seconds.
<3> [248.622427]       Tainted: G     U  W         5.4.0-rc1-CI-CI_DRM_6977+ #1
<3> [248.622556] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
<6> [248.622702] kworker/u8:1    D12472    41      2 0x80004000
<6> [248.623147] Workqueue: mock contexts_free_worker [i915]
<4> [248.623381] Call Trace:
<4> [248.623453]  ? __schedule+0x2ef/0x7f0
<4> [248.623526]  schedule+0x34/0xc0
<4> [248.623555]  schedule_preempt_disabled+0xf/0x20
<4> [248.623581]  __mutex_lock+0x286/0x9d0
<4> [248.623611]  ? __lock_acquire+0x460/0x15d0
<4> [248.624128]  ? contexts_free_worker+0x20/0xa0 [i915]
<4> [248.624775]  ? contexts_free_worker+0x20/0xa0 [i915]
<4> [248.625235]  contexts_free_worker+0x20/0xa0 [i915]
<4> [248.625358]  process_one_work+0x26a/0x620
<4> [248.625437]  worker_thread+0x37/0x380
<4> [248.625485]  ? process_one_work+0x620/0x620
<4> [248.625512]  kthread+0x119/0x130
<4> [248.625543]  ? kthread_park+0x80/0x80
<4> [248.625585]  ret_from_fork+0x3a/0x50
<4> [248.625728] 
Showing all locks held in the system:
<4> [248.625761] 1 lock held by khungtaskd/34:
<4> [248.625778]  #0: ffffffff822479a0 (rcu_read_lock){....}, at: debug_show_all_locks+0xe/0x1a0
<4> [248.625834] 3 locks held by kworker/u8:1/41:
<4> [248.625850]  #0: ffff88816b134e70 ((wq_completion)mock){+.+.}, at: process_one_work+0x1de/0x620
<4> [248.625968]  #1: ffffc90000187e78 ((work_completion)(&i915->contexts.free_work)){+.+.}, at: process_one_work+0x1de/0x620
<4> [248.626010]  #2: ffff88816e490a40 (&dev->struct_mutex){+.+.}, at: contexts_free_worker+0x20/0xa0 [i915]
<4> [248.626511] 3 locks held by kworker/1:1H/233:
<4> [248.626534] 1 lock held by in:imklog/397:
<4> [248.626562] 3 locks held by dmesg/1034:
<4> [248.626582] 1 lock held by igt_runner/1051:
<4> [248.626602] 2 locks held by i915_selftest/1173:
<4> [248.626620]