network_WiFi_SimpleConnect.wifi_check1x_WEP is regularly failing with Lost ping packets error.

 
https://stainless.corp.google.com/search?view=list&first_date=2018-10-19&last_date=2018-11-01&suite=wifi_release%7Cwifi_matfunc&test=network_WiFi_SimpleConnect.wifi_check1x_WEP&board=grunt&status=GOOD&status=FAIL&reason=Lost+ping+packets%3A+PingResult&exclude_cts=true&exclude_not_run=false&exclude_non_release=false&exclude_au=true&exclude_acts=true&exclude_retried=true&exclude_non_production=false

I don't see that for any other test case on grunt,

https://stainless.corp.google.com/search?view=matrix&row=build&col=test&first_date=2018-10-19&last_date=2018-11-01&suite=wifi_release%7Cwifi_matfunc&board=grunt&status=GOOD&status=FAIL&exclude_cts=true&exclude_not_run=false&exclude_non_release=false&exclude_au=true&exclude_acts=true&exclude_retried=true&exclude_non_production=false

Sample failures. 

11/01 09:52:50.296 INFO |wifi_test_context_:0281| Connected successfully to SimpleConnect_a_0xg9l_ch1, signal level: -17.
11/01 09:52:50.341 DEBUG|          ssh_host:0310| Running (ssh) 'mkdir -p /tmp' from 'assert_disconnect_count|get_event_logger|__init__|get_tmp_dir|run|run_very_slowly'
11/01 09:52:50.849 DEBUG|          ssh_host:0310| Running (ssh) 'mktemp -d /tmp/autoserv-XXXXXX' from 'assert_disconnect_count|get_event_logger|__init__|get_tmp_dir|run|run_very_slowly'
11/01 09:52:51.338 DEBUG|             utils:0287| [stdout] /tmp/autoserv-842rBR
11/01 09:52:51.419 DEBUG|          ssh_host:0310| Running (ssh) 'nohup /usr/sbin/iw event -t </dev/null >/tmp/autoserv-842rBR/iw_event.log 2>&1 & echo $!;date +%s' from 'run_once|__enter__|assert_disconnect_count|start|run|run_very_slowly'
11/01 09:52:51.942 DEBUG|             utils:0287| [stdout] 9499
11/01 09:52:51.943 DEBUG|             utils:0287| [stdout] 1541091171
11/01 09:52:51.945 INFO | site_linux_system:0738| Pinging from the client.
11/01 09:52:51.962 DEBUG|          ssh_host:0310| Running (ssh) 'ping -c 10 192.168.0.254' from 'run_once|assert_ping_from_dut|ping|ping|run|run_very_slowly'
11/01 09:52:52.307 DEBUG|             utils:0287| [stdout] PING 192.168.0.254 (192.168.0.254) 56(84) bytes of data.
11/01 09:52:52.307 DEBUG|             utils:0287| [stdout] 64 bytes from 192.168.0.254: icmp_seq=1 ttl=64 time=3.10 ms
11/01 09:53:02.494 DEBUG|             utils:0287| [stdout] 
11/01 09:53:02.494 DEBUG|             utils:0287| [stdout] --- 192.168.0.254 ping statistics ---
11/01 09:53:02.494 DEBUG|             utils:0287| [stdout] 10 packets transmitted, 1 received, 90% packet loss, time 9199ms
11/01 09:53:02.494 DEBUG|             utils:0287| [stdout] rtt min/avg/max/mdev = 3.104/3.104/3.104/0.000 ms
11/01 09:53:02.515 DEBUG|          ssh_host:0310| Running (ssh) 'kill 9499' from '__exit__|assert_disconnect_count|__exit__|stop|run|run_very_slowly'
11/01 09:53:03.119 DEBUG|      abstract_ssh:0415| get_file. source: /tmp/autoserv-842rBR/iw_event.log, dest: ./debug/iw_event_0.log, delete_dest: False,preserve_perm: True, preserve_symlinks:False
11/01 09:53:03.159 DEBUG|          ssh_host:0310| Running (ssh) 'rsync --version' from 'stop|get_file|use_rsync|check_rsync|run|run_very_slowly'
11/01 09:53:03.615 DEBUG|      abstract_ssh:0427| Using Rsync.
11/01 09:53:03.616 DEBUG|             utils:0219| Running 'rsync -L  --timeout=1800 --rsh='/usr/bin/ssh -a -x  -o Protocol=2 -o StrictHostKeyChecking=no -o UserKnownHostsFile=/dev/null -o BatchMode=yes -o ConnectTimeout=30 -o ServerAliveInterval=900 -o ServerAliveCountMax=3 -o ConnectionAttempts=4 -l root -p 22' -az --no-o --no-g  root@chromeos15-row4-rack12-host2:"/tmp/autoserv-842rBR/iw_event.log" "/usr/local/autotest/results/lxc_job_folder/network_WiFi_SimpleConnect.wifi_check1x_WEP/debug/iw_event_0.log"'
11/01 09:53:04.475 INFO |   iw_event_logger:0088| iw event log saved to ./debug/iw_event_0.log
11/01 09:53:04.479 DEBUG|              test:0381| Test failed due to Lost ping packets: PingResult(received=1, max_latency=3.104, loss=90, min_latency=3.104, dev_latency=0.0, avg_latency=3.104, sent=10).. Exception log follows the after_iteration_hooks.



Traceback (most recent call last):
  File "/usr/local/autotest/client/common_lib/test.py", line 600, in _exec
    _call_test_function(self.execute, *p_args, **p_dargs)
  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 464, in execute
    postprocess_profiled_run, args, dargs)
  File "/usr/local/autotest/client/common_lib/test.py", line 371, in _call_run_once
    self.run_once(*args, **dargs)
  File "/usr/local/autotest/server/site_tests/network_WiFi_SimpleConnect/network_WiFi_SimpleConnect.py", line 39, in run_once
    self.context.assert_ping_from_dut()
  File "/usr/local/autotest/server/cros/network/wifi_test_context_manager.py", line 303, in assert_ping_from_dut
    self.client.ping(ping_config)
  File "/usr/local/autotest/server/site_linux_system.py", line 739, in ping
    return self._ping_runner.ping(ping_config)
  File "/usr/local/autotest/client/common_lib/cros/network/ping_runner.py", line 367, in ping
    raise error.TestFail('Lost ping packets: %r.' % ping_result)
TestFail: Lost ping packets: PingResult(received=1, max_latency=3.104, loss=90, min_latency=3.104, dev_latency=0.0, avg_latency=3.104, sent=10).