Interesting error in the screenshot. Any chance you could take a look, Neil? :) https://tbpl.mozilla.org/php/getParsedLog.php?id=33745272&tree=Mozilla-Aurora Ubuntu ASAN VM 12.04 x64 mozilla-aurora opt test mochitest-other on 2014-01-29 07:17:17 PST for push 21ff475b03d7 slave: tst-linux64-ec2-311 07:40:27 INFO - 30262 INFO TEST-PASS | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | non-instant accept system int 07:40:27 INFO - 30263 INFO TEST-PASS | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | non-instant accept system bool 07:40:27 INFO - 30264 INFO TEST-PASS | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | non-instant accept system string 07:40:27 INFO - 30265 INFO TEST-PASS | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | non-instant accept system wstring 07:40:27 INFO - 30266 INFO TEST-PASS | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | non-instant accept system unichar 07:40:27 INFO - 30267 INFO TEST-KNOWN-FAIL | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | non-instant accept system file 07:40:29 INFO - OS Posting message [see log] 07:40:29 INFO - OS Message posted 07:40:29 INFO - OS Received message from worker {"ok":73611,"id":65,"telemetry":{"FX_SESSION_RESTORE_WRITE_FILE_MS":1}} 07:45:59 WARNING - TEST-UNEXPECTED-FAIL | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | application timed out after 330 seconds with no output 07:45:59 INFO - Xlib: extension "RANDR" missing on display ":0". 07:46:02 INFO - SCREENSHOT: 07:46:03 INFO - Can't trigger Breakpad, just killing process 07:46:03 WARNING - TEST-UNEXPECTED-FAIL | chrome://mochitests/content/chrome/toolkit/content/tests/chrome/test_preferences.xul | application terminated with exit code 9 07:46:03 INFO - INFO | runtests.py | Application ran for: 0:22:26.067736 07:46:03 INFO - INFO | zombiecheck | Reading PID log: /tmp/tmpxuWBkfpidlog 07:46:03 INFO - ==> process 2437 launched child process 2499 07:46:03 INFO - ==> process 2437 launched child process 2526 07:46:03 INFO - ==> process 2437 launched child process 2537 07:46:03 INFO - ==> process 2437 launched child process 2777 07:46:03 INFO - ==> process 2437 launched child process 2782 07:46:03 INFO - ==> process 2437 launched child process 2787 07:46:03 INFO - ==> process 2437 launched child process 2831 07:46:03 INFO - ==> process 2437 launched child process 2836 07:46:03 INFO - ==> process 2437 launched child process 2841 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2499 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2526 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2537 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2777 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2782 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2787 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2831 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2836 07:46:03 INFO - INFO | zombiecheck | Checking for orphan process with PID: 2841 07:46:03 INFO - WARNING | leakcheck | refcount logging is off, so leaks can't be detected! 07:46:03 INFO - runtests.py | Running tests: end. 07:46:03 INFO - Exception in thread Thread-1 (most likely raised during interpreter shutdown): 07:46:03 INFO - Traceback (most recent call last): 07:46:03 INFO - File "/usr/lib/python2.7/threading.py", line 551, in __bootstrap_inner 07:46:03 INFO - File "/usr/lib/python2.7/threading.py", line 504, in run 07:46:03 INFO - File "/builds/slave/test/build/venv/local/lib/python2.7/site-packages/mozprocess/processhandler.py", line 703, in _processOutput 07:46:03 INFO - File "/builds/slave/test/build/venv/local/lib/python2.7/site-packages/mozprocess/processhandler.py", line 665, in readWithTimeout 07:46:03 INFO - File "/builds/slave/test/build/venv/local/lib/python2.7/site-packages/mozprocess/processhandler.py", line 796, in _readWithTimeout 07:46:03 INFO - <type 'exceptions.AttributeError'>: 'NoneType' object has no attribute 'read' 07:46:03 INFO - Exception AttributeError: "'NoneType' object has no attribute 'isWin'" in <bound method Process.__del__ of <mozprocess.processhandler.Process object at 0x210c290>> ignored 07:46:03 ERROR - Return code: 2304

Comment on attachment 8367594 [details] index.png If the error you mean, the 'allow (null) to run test' that's a message about a blocked plugin. Likely, some earlier test triggered it and isn't related to the problem. The test itself is either failing to open a child dialog, or failing in InitTestPrefs. I didn't write this test so I'm not sure offhand, and since it has only failed happened once, I'm not sure it will be easy to debug. I'll take a quick look tomorrow.

May have been caused by bug 474527.

Are there any cases in the preferences test where an event handler (onbeforeaccept) is returning false on a window being tested? Like connection.xul? Bug 474527 made it so that prefwindows returning false on onbeforeaccept don't close. A test that doesn't clean up after itself (eg, if you only partially fill in proxy details on connection.xul, this can happen) would hang on this.

This might have to do with http://mxr.mozilla.org/mozilla-central/source/toolkit/content/widgets/preferences.xml#1034

Inactive; closing (see bug 1180138).