It starts show up on daisy_skate_chrome-pfq from https://uberchromegw.corp.google.com/i/chromeos/builders/daisy_skate-chrome-pfq/builds/3752 (Maybe earlier. Since PFQ has been red for a while, other failures may have covered this error.

Selected error messages:
21:54:30: ERROR: BaseException in _RunParallelStages <class 'chromite.lib.parallel.ProcessSilentTimeout'>: No output from <_BackgroundTask(_BackgroundTask-7:7:4, started)> for 8640 seconds

<class 'chromite.lib.failures_lib.StepFailure'>: 
Traceback (most recent call last):
  File "/b/cbuild/repository/chromite/lib/parallel.py", line 441, in _Run
    self._task(*self._task_args, **self._task_kwargs)
  File "/b/cbuild/repository/chromite/cbuildbot/stages/generic_stages.py", line 648, in Run
    raise failures_lib.StepFailure()
StepFailure
Traceback (most recent call last):
  File "/b/cbuild/repository/chromite/cbuildbot/builders/generic_builders.py", line 119, in _RunParallelStages
    parallel.RunParallelSteps(steps)
  File "/b/cbuild/repository/chromite/lib/parallel.py", line 678, in RunParallelSteps
    return [queue.get_nowait() for queue in queues]
  File "/b/cbuild/repository/chromite/lib/parallel.py", line 675, in RunParallelSteps
    pass
  File "/usr/lib/python2.7/contextlib.py", line 24, in __exit__
    self.gen.next()
  File "/b/cbuild/repository/chromite/lib/parallel.py", line 561, in ParallelTasks
    raise BackgroundFailure(exc_infos=errors)
BackgroundFailure: <class 'chromite.lib.parallel.ProcessSilentTimeout'>: No output from <_BackgroundTask(_BackgroundTask-7:7:4, started)> for 8640 seconds

<class 'chromite.lib.failures_lib.StepFailure'>: 
Traceback (most recent call last):
  File "/b/cbuild/repository/chromite/lib/parallel.py", line 441, in _Run
    self._task(*self._task_args, **self._task_kwargs)
  File "/b/cbuild/repository/chromite/cbuildbot/stages/generic_stages.py", line 648, in Run
    raise failures_lib.StepFailure()
StepFailure

Other error messages might be related:
04-18-2017 [21:49:53] Attempting to display pool info: bvt
  host: chromeos4-row9-rack5-host3, status: Repairing, locked: False diagnosis: Failed repair
  labels: ['board_freq_mem:daisy_skate_1.7GHz_2GB', 'gpu_family:mali', 'graphics:gles', 'skate', 'hw_video_acc_enc_h264', 'audio_loopback_dongle', 'cts_abi_arm', 'hw_video_acc_vp8', 'internal_display', 'os:cros', 'power:battery', 'hw_video_acc_h264', 'storage:mmc', 'webcam', 'servo', 'board:daisy_skate', 'sku:skate_cpu_skate_2Gb', 'variant:skate', 'touchpad', 'phase:PVT', 'pool:bvt', 'ec:cros', 'bluetooth', 'cros-version:daisy_skate-release/R58-9334.42.0']

  host: chromeos4-row9-rack7-host5, status: Repair Failed, locked: False diagnosis: Failed repair
  labels: ['skate', 'board_freq_mem:daisy_skate_1.7GHz_2GB', 'gpu_family:mali', 'graphics:gles', 'ec:cros', 'hw_video_acc_enc_h264', 'audio_loopback_dongle', 'cts_abi_arm', 'hw_video_acc_vp8', 'internal_display', 'os:cros', 'power:battery', 'hw_video_acc_h264', 'storage:mmc', 'webcam', 'servo', 'board:daisy_skate', 'sku:skate_cpu_skate_2Gb', 'variant:skate', 'touchpad', 'phase:PVT', 'bluetooth', 'pool:bvt']