logs @ https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/58318040-chromeos-test/chromeos1-grover-host1/network_WiFi_AttenuatedPerf.ht40_ch001/debug/

Failures on varius builds @
https://wmatrix.googleplex.com/failures/unfiltered?suites=wifi_atten_perf&tests=network_WiFi_AttenuatedPerf.ht40_ch001&days_back=20&releases=tot&platforms=daisy


Sample failure

Traceback (most recent call last):
  File "/usr/local/autotest/client/common_lib/test.py", line 596, in _exec
    _call_test_function(self.execute, *p_args, **p_dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 806, in _call_test_function
    raise error.UnhandledTestFail(e)
UnhandledTestFail: Unhandled AttributeError: 'NoneType' object has no attribute 'exit_status'
Traceback (most recent call last):
  File "/usr/local/autotest/client/common_lib/test.py", line 800, in _call_test_function
    return func(*args, **dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 457, in execute
    dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 343, in _call_run_once_with_retry
    postprocess_profiled_run, args, dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 372, in _call_run_once
    self.run_once(*args, **dargs)
  File "/usr/local/autotest/server/site_tests/network_WiFi_AttenuatedPerf/network_WiFi_AttenuatedPerf.py", line 89, in run_once
    results = session.run(config)
  File "/usr/local/autotest/server/cros/network/netperf_session.py", line 112, in run
    result = runner.run(ignore_failures=self._ignore_failures)
  File "/usr/local/autotest/server/cros/network/netperf_runner.py", line 577, in run
    if result.exit_status and not ignore_failures:
AttributeError: 'NoneType' object has no attribute 'exit_status'