Turned out the subsystem (default) was recorded as pass in cidb, although some tests failed in the build. Pass this to shuqianz@ to debug why the subsystem was parsed to 'pass', it might be because many tests were using the same short name "graphics_dEQP", and one failed "graphics_dEQP" was overwritten by the other successful ones. 

https://uberchromegw.corp.google.com/i/chromeos/builders/nyan_kitty-paladin/builds/948/steps/HWTest%20%5Bbvt-cq%5D/logs/stdio


07:35:49: INFO: pass_subsystems: set([u'default']), fail_subsystems: set([])


mysql> select * from buildMessageTable where build_id=1367287;
+--------+----------+--------------+-----------------+---------------+---------------------+------------+
| id     | build_id | message_type | message_subtype | message_value | timestamp           | board      |
+--------+----------+--------------+-----------------+---------------+---------------------+------------+
| 974292 |  1367287 | subsystems   | subsystem_pass  | default       | 2017-03-07 15:35:53 | nyan_kitty |
+--------+----------+--------------+-----------------+---------------+---------------------+------------+



Some bad CLs can get into the CQ because of this bug. 

There do exist multiple graphics_dEQP tests scheduled accross several DUTs, and only one of them failed due to DUT reboot unexpectedly. 

The failed one is:
START	105209516-chromeos-test/chromeos4-row13-rack8-host10/graphics_dEQP	graphics_dEQP	timestamp=1488899445	localtime=Mar 07 07:10:45	
	FAIL	105209516-chromeos-test/chromeos4-row13-rack8-host10/graphics_dEQP	graphics_dEQP	timestamp=1488900393	localtime=Mar 07 07:26:33	Autotest client terminated unexpectedly: DUT rebooted during the test run.
END FAIL	105209516-chromeos-test/chromeos4-row13-rack8-host10/graphics_dEQP	graphics_dEQP	timestamp=1488900393	localtime=Mar 07 07:26:33

However, from both the suite log and the DUT log, this test seems to be passed:
suite_log:
http://cautotest.corp.google.com/afe/#tab_id=view_job&object_id=105208845

DUT history:
host: chromeos4-row13-rack8-host10, status: Ready, locked: False diagnosis: Working
labels: ['bluetooth', 'power:AC_only', 'gpu_family:tegra', 'nyan_kitty', 'board:nyan_kitty', 'board_freq_mem:nyan_kitty_2.1GHz_4GB', 'graphics:gles', '4k_video', 'audio_loopback_dongle', 'variant:kitty', 'sku:kitty_cpu_nyan_4Gb', 'cts_abi_arm', 'os:cros', 'storage:mmc', 'webcam', 'phase:PVT', 'servo', 'hw_video_acc_vp8', 'hw_video_acc_h264', 'hw_video_acc_enc_h264', 'hw_video_acc_enc_vp8', 'pool:cq', 'ec:cros', 'internal_display', 'cros-version:nyan_kitty-paladin/R59-9346.0.0-rc2']
Last 10 jobs within 1:48:00:
105541789 nyan_kitty-paladin/R59-9346.0.0-rc2/suite_attr_wrapper/graphics_dEQP.gles3.accuracy started on: 2017-03-07 07:10:15 status Completed
2710316 Reset started on: 2017-03-07 07:09:41 status PASS

DUT test log:
INFO	----	----	kernel=3.10.18	localtime=Mar 07 07:10:28	timestamp=1488899428	
START	----	----	timestamp=1488899445	localtime=Mar 07 07:10:45	
	START	graphics_dEQP	graphics_dEQP	timestamp=1488899445	localtime=Mar 07 07:10:45	
		FAIL	----	----	timestamp=1488900393	localtime=Mar 07 07:26:33	Autotest client terminated unexpectedly: DUT rebooted during the test run.
	END FAIL	----	----	timestamp=1488900393	localtime=Mar 07 07:26:33	
END GOOD	----	----	timestamp=1488900393	localtime=Mar 07 07:26:33	

The test is end with Good status, which means it passed. I also checked the test debug log, this test did finish. https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/105209516-chromeos-test/chromeos4-row13-rack8-host10/. The subsystem board aware submission is to filter out the subsystems from the failed tests, and fail those changes who touch the subsystems. Currently, all changes are default to test subsystem:default. For this case, there is actually no fail tests, so the subsystem is doing the right thing. 

No idea why all tests passed, the HWTest stage failed.

jrbarnette@, ideas about why all tests passed as shuqianz@ pasted, but HWTest still failed with

graphics_dEQP                               FAIL: Autotest client terminated unexpectedly: DUT rebooted during the test run.