Digging a bit into the signatures, I see three main buckets of signatures:
1. Crashes at arbitrary places caused by [MOZ_CRASH("Shutdown hanging before starting.");](https://searchfox.org/mozilla-central/source/toolkit/components/terminator/nsTerminator.cpp#221) or by [MOZ_CRASH("Shutdown too long, probably frozen, causing a crash.");](https://searchfox.org/mozilla-central/source/toolkit/components/terminator/nsTerminator.cpp#234)
1.1 [shutdownhang | nsThread::Shutdown | mozilla::net::nsSocketTransportService::ShutdownThread](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20nsThread%3A%3AShutdown%20%7C%20mozilla%3A%3Anet%3A%3AnsSocketTransportService%3A%3AShutdownThread#aggregations)
Happens mostly on 68.x but has some occurrences also on 75.0.
1.2 [shutdownhang | mozilla::net::ShutdownEvent::PostAndWait](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3Anet%3A%3AShutdownEvent%3A%3APostAndWait#aggregations)
Here 75.0 and 68.x are dominant, but the total volume is one order of magnitude lower than 1.1.
1.3 [shutdownhang | mozilla::SpinEventLoopUntil<T> | mozilla::net::nsHttpConnectionMgr::Shutdown](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3ASpinEventLoopUntil%3CT%3E%20%7C%20mozilla%3A%3Anet%3A%3AnsHttpConnectionMgr%3A%3AShutdown#aggregations)
Here we have only versions up to 68.x. and mostly ESR. Volume is about half of 1.1.
1.4 [shutdownhang | mozilla::net::nsHttpConnectionMgr::Shutdown](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3Anet%3A%3AnsHttpConnectionMgr%3A%3AShutdown#aggregations)
Here 75 and 52.9.0esr dominate the ranks. I assume this to be just a variant of 1.3.
1.5 [shutdownhang | mozilla::dom::workers::RuntimeService::Cleanup](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3Adom%3A%3Aworkers%3A%3ARuntimeService%3A%3ACleanup#aggregations)
Happens only on versions up to 52.9.0esr and can be safely ignored.
All these crashes seem not really worker related to me (or I am overlooking something not evident), at least we do not know, what caused the hang.
2. Crashes with worker specific "Workers Hanging ..." MOZ_CRASH messages
2.1. [mozilla::dom::workerinternals::RuntimeService::CrashIfHanging](https://crash-stats.mozilla.org/signature/?signature=mozilla%3A%3Adom%3A%3Aworkerinternals%3A%3ARuntimeService%3A%3ACrashIfHanging#aggregations)
(This signature has been added twice, it seems.)
Here we have a collection of many different (but similar) MOZ_CRASH reasons. I assume, they reflect the evolution of those messages through the different versions (as we can see versions back to 60.2.0esr here).
The 4 top scorers (making together more than 60%) are:
```
1 Workers Hanging - 1|A:1|S:0|Q:0-BC:1|WorkerDebuggeeRunnable::mSender 393 21.30 %
2 Workers Hanging - 1|A:1|S:0|Q:0-BC:0Dispatch Error 283 15.34 %
3 Workers Hanging - 1|A:3|S:0|Q:0-BC:0Dispatch Error-BC:0Dispatch Error-BC:0Dispatch Error 282 15.28 %
4 Workers Hanging - 1|A:1|S:0|Q:0-BC:1|IDBOpenDBRequest 165 8.94 %
5 Workers Hanging - 1|A:2|S:0|Q:0-BC:0Dispatch Error-BC:0Dispatch Error 141 7.64 %
```
These are the cases to care (most) about in this bug, I think. It would be interesting to relate the different messages to the versions we see in order to narrow down similar causes.
2.2 [mozilla::dom::workers::RuntimeService::CrashIfHanging](https://crash-stats.mozilla.org/signature/?signature=mozilla%3A%3Adom%3A%3Aworkers%3A%3ARuntimeService%3A%3ACrashIfHanging#aggregations)
This signature happens on very old, unsupported versions only and can be safely ignored.
3. Signatures without MOZ_CRASH message at all
3.1 [mozilla::net::CacheFileIOManager::SyncRemoveDir](https://crash-stats.mozilla.org/signature/?signature=mozilla%3A%3Anet%3A%3ACacheFileIOManager%3A%3ASyncRemoveDir#aggregations)
Has a very low but recent volume. I think this signature deserves a bug on its own.
3.2 [shutdownhang | static bool mozilla::SpinEventLoopUntil<T> | mozilla::net::nsHttpConnectionMgr::Shutdown](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20static%20bool%20mozilla%3A%3ASpinEventLoopUntil%3CT%3E%20%7C%20mozilla%3A%3Anet%3A%3AnsHttpConnectionMgr%3A%3AShutdown#aggregations)
Has no occurrences at all in our data and can be removed from the signatures.
:mccr8, do I read well in the crash data and can we adjust a bit the signatures relevant for this bug?
Bug 1435343 Comment 70 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
Digging a bit into the signatures, I see three main buckets of signatures:
1. Crashes at arbitrary places caused by [MOZ_CRASH("Shutdown hanging before starting.");](https://searchfox.org/mozilla-central/source/toolkit/components/terminator/nsTerminator.cpp#221) or by [MOZ_CRASH("Shutdown too long, probably frozen, causing a crash.");](https://searchfox.org/mozilla-central/source/toolkit/components/terminator/nsTerminator.cpp#234)
1.1 [shutdownhang | nsThread::Shutdown | mozilla::net::nsSocketTransportService::ShutdownThread](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20nsThread%3A%3AShutdown%20%7C%20mozilla%3A%3Anet%3A%3AnsSocketTransportService%3A%3AShutdownThread#aggregations)
Happens mostly on 68.x but has some occurrences also on 75.0.
1.2 [shutdownhang | mozilla::net::ShutdownEvent::PostAndWait](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3Anet%3A%3AShutdownEvent%3A%3APostAndWait#aggregations)
Here 75.0 and 68.x are dominant, but the total volume is one order of magnitude lower than 1.1.
1.3 [shutdownhang | mozilla::SpinEventLoopUntil<T> | mozilla::net::nsHttpConnectionMgr::Shutdown](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3ASpinEventLoopUntil%3CT%3E%20%7C%20mozilla%3A%3Anet%3A%3AnsHttpConnectionMgr%3A%3AShutdown#aggregations)
Here we have only versions up to 68.x. and mostly ESR. Volume is about half of 1.1.
1.4 [shutdownhang | mozilla::net::nsHttpConnectionMgr::Shutdown](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3Anet%3A%3AnsHttpConnectionMgr%3A%3AShutdown#aggregations)
Here 75 and 52.9.0esr dominate the ranks. I assume this to be just a variant of 1.3.
1.5 [shutdownhang | mozilla::dom::workers::RuntimeService::Cleanup](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20mozilla%3A%3Adom%3A%3Aworkers%3A%3ARuntimeService%3A%3ACleanup#aggregations)
Happens only on versions up to 52.9.0esr and can be safely ignored.
All these crashes seem not really worker related to me (or I am overlooking something not evident), at least we do not know, what caused the hang.
2. Crashes with worker specific "Workers Hanging ..." MOZ_CRASH messages
2.1. [mozilla::dom::workerinternals::RuntimeService::CrashIfHanging](https://crash-stats.mozilla.org/signature/?signature=mozilla%3A%3Adom%3A%3Aworkerinternals%3A%3ARuntimeService%3A%3ACrashIfHanging#aggregations)
(This signature has been added twice, it seems.)
Here we have a collection of many different (but similar) MOZ_CRASH reasons. I assume, they reflect the evolution of those messages through the different versions (as we can see versions back to 60.2.0esr here).
The 4 top scorers (making together more than 60%) are:
```
1 Workers Hanging - 1|A:1|S:0|Q:0-BC:1|WorkerDebuggeeRunnable::mSender 393 21.30 %
2 Workers Hanging - 1|A:1|S:0|Q:0-BC:0Dispatch Error 283 15.34 %
3 Workers Hanging - 1|A:3|S:0|Q:0-BC:0Dispatch Error-BC:0Dispatch Error-BC:0Dispatch Error 282 15.28 %
4 Workers Hanging - 1|A:1|S:0|Q:0-BC:1|IDBOpenDBRequest 165 8.94 %
5 Workers Hanging - 1|A:2|S:0|Q:0-BC:0Dispatch Error-BC:0Dispatch Error 141 7.64 %
```
. These are the cases to care (most) about in this bug, I think. It would be interesting to relate the different messages to the versions we see in order to narrow down similar causes.
. 2.2 [mozilla::dom::workers::RuntimeService::CrashIfHanging](https://crash-stats.mozilla.org/signature/?signature=mozilla%3A%3Adom%3A%3Aworkers%3A%3ARuntimeService%3A%3ACrashIfHanging#aggregations)
This signature happens on very old, unsupported versions only and can be safely ignored.
3. Signatures without MOZ_CRASH message at all
3.1 [mozilla::net::CacheFileIOManager::SyncRemoveDir](https://crash-stats.mozilla.org/signature/?signature=mozilla%3A%3Anet%3A%3ACacheFileIOManager%3A%3ASyncRemoveDir#aggregations)
Has a very low but recent volume. I think this signature deserves a bug on its own.
3.2 [shutdownhang | static bool mozilla::SpinEventLoopUntil<T> | mozilla::net::nsHttpConnectionMgr::Shutdown](https://crash-stats.mozilla.org/signature/?signature=shutdownhang%20%7C%20static%20bool%20mozilla%3A%3ASpinEventLoopUntil%3CT%3E%20%7C%20mozilla%3A%3Anet%3A%3AnsHttpConnectionMgr%3A%3AShutdown#aggregations)
Has no occurrences at all in our data and can be removed from the signatures.
:mccr8, do I read well in the crash data and can we adjust a bit the signatures relevant for this bug?
(edit: it seems I am unable to format this well - hope it works anyway)