On ToT M56 build.
Traceback (most recent call last):
  File "/usr/local/autotest/server/server_job.py", line 780, in run
    self._execute_code(server_control_file, namespace)
  File "/usr/local/autotest/server/server_job.py", line 1280, in _execute_code
    execfile(code_file, namespace, namespace)
  File "/usr/local/autotest/results/82870504-chromeos-test/hostless/control.srv", line 61, in <module>
    ds.stage_artifacts(build, artifacts=['au_suite'])
  File "/usr/local/autotest/client/common_lib/cros/retry.py", line 171, in func_retry
    remaining_time)
  File "/usr/local/autotest/client/common_lib/cros/retry.py", line 95, in timeout
    default_result = func(*args, **kwargs)
  File "/usr/local/autotest/client/common_lib/cros/dev_server.py", line 193, in wrapper
    return method(*args, **kwargs)
  File "/usr/local/autotest/client/common_lib/cros/dev_server.py", line 1306, in stage_artifacts
    self._stage_artifacts(image, artifacts, files, archive_url)
  File "/usr/local/autotest/client/common_lib/cros/dev_server.py", line 997, in _stage_artifacts
    'stage_artifacts timed out: %s' % staging_info)
DevServerException: stage_artifacts timed out: build=banjo-release/R56-8938.0.0, artifacts=['au_suite'], files=, archive_url=gs://chromeos-image-archive/banjo-release/R56-8938.0.0
10/27 07:24:41.410 INFO |        server_job:0153| INFO	----	----	timestamp=1477578281	job_abort_reason=stage_artifacts timed out: build=banjo-release/R56-8938.0.0, artifacts=['au_suite'], files=, archive_url=gs://chromeos-image-archive/banjo-release/R56-8938.0.0	localtime=Oct 27 07:24:41	stage_artifacts timed out: build=banjo-release/R56-8938.0.0, artifacts=['au_suite'], files=, archive_url=gs://chromeos-image-archive/banjo-release/R56-8938.0.0

Link to build:
https://uberchromegw.corp.google.com/i/chromeos/builders/banjo-release/builds/505