Crash report: https://crash-stats.mozilla.org/report/index/4ad12d75-43fe-4cb6-876e-779e30200904

Top 10 frames of crashing thread:

0 xul.dll nsWrapperCache::GetWrapper const dom/base/nsWrapperCacheInlines.h:27
1 xul.dll mozilla::dom::PrintCallback::Call dom/bindings/HTMLCanvasElementBinding.cpp:48
2 xul.dll mozilla::dom::HTMLCanvasElement::CallPrintCallback dom/html/HTMLCanvasElement.cpp:502
3 xul.dll mozilla::detail::RunnableMethodImpl< xpcom/threads/nsThreadUtils.h:1240
4 xul.dll mozilla::SchedulerGroup::Runnable::Run xpcom/threads/SchedulerGroup.cpp:146
5 xul.dll mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal xpcom/threads/TaskController.cpp:512
6 xul.dll mozilla::detail::RunnableFunction<`lambda at /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:83:7'>::Run xpcom/threads/nsThreadUtils.h:577
7 xul.dll nsThread::ProcessNextEvent xpcom/threads/nsThread.cpp:1234
8 xul.dll mozilla::ipc::MessagePump::Run ipc/glue/MessagePump.cpp:87
9 xul.dll MessageLoop::RunHandler ipc/chromium/src/base/message_loop.cc:327

Affected versions

• 82.0a1 (BuildId:20200903151816)
• 81.0b6 (BuildId:20200903205131) - This crash signature is not encountered in B6 but B6 crashes (with a different signature) as well with the same steps - See Bug 1663134

Affected platforms

• Windows 10 64bit
• Ubuntu 18.04 64bit
• macOS 10.14

Steps to reproduce

• On my main profile it seems that simply clicking print leads to a tab crash:

1. Launch Firefox.
2. Access the following link
3. Click the print button.

Additional Steps

• On new profiles, in order to reproduce this issue with ease you need to:

1. Launch Firefox.
2. Access the following link
3. Spam open an close (the print button) via esc keyboard

Expected result

• Firefox is stable.

Actual result

• Tab crash

Regression Window

• This is a regression.
• Pushlog: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=b74ab1682deaf69e9d0eac0fb9c29e7e7a5a7a0b&tochange=85e7a3055098f2f8f8d7abc59d7f0d6215e47984
• Possible Regressor: Bug 1662426

Additional Information

• For further information regarding this issue please observe the attached screencast.
• On my main profile I’ve encountered the crash signature mentioned in 1663129 (same steps) only once
• [Suggested Severity] S1- I think that this is S1 :(

This was fixed by bug 1663053. I believe. Isn't it?

Yes, it seems like it (verified it with an opt build)

I think that the fix for Bug 1663053 may also fix this crash and Bug 1663129 & Bug 1663134

Leaving a ni? on myself to verify this in the next Nightly.

Sorry for raising the alarm :D

In case it helps for confirming that, I've pushed to Try a Beta build + the fix from bug 1663053. Once the builds complete, you can download them from the "artifacts" tab.

https://treeherder.mozilla.org/#/jobs?repo=try&revision=d0242a8b6eea981abff6161efc2436e947d8ea53

I can confirm that this is verified fixed using Firefox 82.0a1 (BuildId:20200904094341).

The provided try build for beta confirms that this is indeed fixed by Bug 1663053. I'm going to leave the ni? on myself and will verify this once the fix for Bug 1663053 lands in beta.

This issue is verified fixed using Firefox 81.0b7 (BuildId:20200906164749) on Windows 10 64bit, macOS 10.14 & Ubuntu 18.04.