Bug: Intermittent AssertionError: Tried to call get() on InstanceManager that has an existing instance
Status: RESOLVED
Priority: P5
Resolution: DUPLICATE
Created: 2021-07-12 11:33:09+00:00
Resolved: 2021-07-19 06:05:38+00:00

**Filed by:** ncsoregi [at] mozilla.com
**Parsed log:** https://treeherder.mozilla.org/logviewer?job_id=344935086&repo=autoland
**Full log:** https://firefox-ci-tc.services.mozilla.com/api/queue/v1/task/K0fnM4AfTN6lJN_JF2hSow/runs/0/artifacts/public/logs/live_backing.log

---
```
[task 2021-07-12T10:18:23.235Z] 10:18:23     INFO - PID 6456 | [Parent 2256, Main Thread] WARNING: early callback, or time went backwards: '!aAllowIdleDispatch', file /builds/worker/checkouts/gecko/xpcom/threads/IdleTaskRunner.cpp:179
[task 2021-07-12T10:18:25.664Z] 10:18:25     INFO - PID 6456 | #01: mozilla::MediaCache::Update() [dom/media/MediaCache.cpp:1221]
[task 2021-07-12T10:18:25.665Z] 10:18:25     INFO - PID 6456 | #02: mozilla::detail::RunnableFunction<`lambda at /builds/worker/checkouts/gecko/dom/media/MediaCache.cpp:1607:34'>::Run() [xpcom/threads/nsThreadUtils.h:532]
[task 2021-07-12T10:18:25.665Z] 10:18:25     INFO - PID 6456 | #03: nsThread::ProcessNextEvent(bool, bool*) [xpcom/threads/nsThread.cpp:1146]
[task 2021-07-12T10:18:25.666Z] 10:18:25     INFO - PID 6456 | #04: NS_ProcessNextEvent(nsIThread*, bool) [xpcom/threads/nsThreadUtils.cpp:466]
[task 2021-07-12T10:18:25.667Z] 10:18:25     INFO - PID 6456 | #05: mozilla::ipc::MessagePumpForNonMainThreads::Run(base::MessagePump::Delegate*) [ipc/glue/MessagePump.cpp:301]
[task 2021-07-12T10:18:25.667Z] 10:18:25     INFO - PID 6456 | #06: MessageLoop::RunHandler() [ipc/chromium/src/base/message_loop.cc:325]
[task 2021-07-12T10:18:25.668Z] 10:18:25     INFO - PID 6456 | #07: MessageLoop::Run() [ipc/chromium/src/base/message_loop.cc:307]
[task 2021-07-12T10:18:25.669Z] 10:18:25     INFO - PID 6456 | #08: static nsThread::ThreadFunc(void*) [xpcom/threads/nsThread.cpp:394]
[task 2021-07-12T10:18:25.846Z] 10:18:25     INFO - PID 6456 | #09: PR_NativeRunThread(void*) [nsprpub/pr/src/threads/combined/pruthr.c:408]
[task 2021-07-12T10:18:25.846Z] 10:18:25     INFO - PID 6456 | #10: pr_root(void*) [nsprpub/pr/src/md/windows/w95thred.c:140]
[task 2021-07-12T10:18:25.940Z] 10:18:25     INFO - PID 6456 | 
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING - Failure during init Traceback (most recent call last):
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 846, in start
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -     **kwargs)
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 564, in start
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -     super().start()
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\base.py", line 254, in start
[task 2021-07-12T10:18:25.944Z] 10:18:25  WARNING -     self(item)
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 600, in __call__
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING -     data = self.stack_fixer(data)
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\venv\lib\site-packages\mozrunner\utils.py", line 280, in stack_fixer_function
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING -     hide_errors=hideErrors,
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\bin\fix_stacks.py", line 92, in fixSymbols
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING -     fix_stacks.stdin.flush()
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING - OSError: [Errno 22] Invalid argument
[task 2021-07-12T10:18:25.945Z] 10:18:25  WARNING - 
[task 2021-07-12T10:18:25.947Z] 10:18:25    ERROR - Traceback (most recent call last):
[task 2021-07-12T10:18:25.947Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 846, in start
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -     **kwargs)
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 564, in start
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -     super().start()
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\base.py", line 254, in start
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -     self(item)
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 600, in __call__
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -     data = self.stack_fixer(data)
[task 2021-07-12T10:18:25.948Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\venv\lib\site-packages\mozrunner\utils.py", line 280, in stack_fixer_function
[task 2021-07-12T10:18:25.949Z] 10:18:25    ERROR -     hide_errors=hideErrors,
[task 2021-07-12T10:18:25.949Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\bin\fix_stacks.py", line 92, in fixSymbols
[task 2021-07-12T10:18:25.949Z] 10:18:25    ERROR -     fix_stacks.stdin.flush()
[task 2021-07-12T10:18:25.949Z] 10:18:25    ERROR - OSError: [Errno 22] Invalid argument
[task 2021-07-12T10:18:25.949Z] 10:18:25    ERROR - 
[task 2021-07-12T10:18:25.952Z] 10:18:25  WARNING - Failure during init Traceback (most recent call last):
[task 2021-07-12T10:18:25.952Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.952Z] 10:18:25  WARNING -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.953Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.953Z] 10:18:25  WARNING -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.953Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.953Z] 10:18:25  WARNING -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.953Z] 10:18:25  WARNING - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.953Z] 10:18:25  WARNING - 
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR - Traceback (most recent call last):
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.955Z] 10:18:25    ERROR - 
[task 2021-07-12T10:18:25.959Z] 10:18:25  WARNING - Failure during init Traceback (most recent call last):
[task 2021-07-12T10:18:25.959Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.959Z] 10:18:25  WARNING -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.959Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.959Z] 10:18:25  WARNING -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.960Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.960Z] 10:18:25  WARNING -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.960Z] 10:18:25  WARNING - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.960Z] 10:18:25  WARNING - 
[task 2021-07-12T10:18:25.961Z] 10:18:25    ERROR - Traceback (most recent call last):
[task 2021-07-12T10:18:25.961Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.961Z] 10:18:25    ERROR -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.962Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.962Z] 10:18:25    ERROR -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.962Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.962Z] 10:18:25    ERROR -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.962Z] 10:18:25    ERROR - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.962Z] 10:18:25    ERROR - 
[task 2021-07-12T10:18:25.965Z] 10:18:25  WARNING - Failure during init Traceback (most recent call last):
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.966Z] 10:18:25  WARNING - 
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR - Traceback (most recent call last):
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.968Z] 10:18:25    ERROR - 
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING - Failure during init Traceback (most recent call last):
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.974Z] 10:18:25  WARNING - 
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR - Traceback (most recent call last):
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.977Z] 10:18:25    ERROR - 
[task 2021-07-12T10:18:25.982Z] 10:18:25  WARNING - Failure during init Traceback (most recent call last):
[task 2021-07-12T10:18:25.982Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.982Z] 10:18:25  WARNING -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.982Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.983Z] 10:18:25  WARNING -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.983Z] 10:18:25  WARNING -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.983Z] 10:18:25  WARNING -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.983Z] 10:18:25  WARNING - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.983Z] 10:18:25  WARNING - 
[task 2021-07-12T10:18:25.985Z] 10:18:25    ERROR - Traceback (most recent call last):
[task 2021-07-12T10:18:25.985Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\testrunner.py", line 209, in init
[task 2021-07-12T10:18:25.986Z] 10:18:25    ERROR -     self.browser.start(group_metadata=group_metadata, **self.browser_settings)
[task 2021-07-12T10:18:25.986Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 844, in start
[task 2021-07-12T10:18:25.986Z] 10:18:25    ERROR -     self.instance = self.instance_manager.get()
[task 2021-07-12T10:18:25.986Z] 10:18:25    ERROR -   File "C:\Users\task_1626083569\build\tests\web-platform\tests\tools\wptrunner\wptrunner\browsers\firefox.py", line 422, in get
[task 2021-07-12T10:18:25.986Z] 10:18:25    ERROR -     assert not self.current, ("Tried to call get() on InstanceManager that has "
[task 2021-07-12T10:18:25.986Z] 10:18:25    ERROR - AssertionError: Tried to call get() on InstanceManager that has an existing instance
[task 2021-07-12T10:18:25.986Z] 10:18:25    ERROR - 
[task 2021-07-12T10:18:25.987Z] 10:18:25 CRITICAL - Max restarts exceeded
[task 2021-07-12T10:18:26.022Z] 10:18:26     INFO - Browser exited with return code 572
[task 2021-07-12T10:18:26.023Z] 10:18:26  WARNING - Firefox didn't exit cleanly, not processing leak logs
[task 2021-07-12T10:18:26.027Z] 10:18:26  WARNING - Firefox didn't exit cleanly, not processing leak logs
[task 2021-07-12T10:18:26.158Z] 10:18:26     INFO - Browser exited with return code 572
```