Testcase found while fuzzing mozilla-central rev 73f050da7d20 (built with --enable-debug and --enable-fuzzing).

Assertion failure: IsSuspended(), at /builds/worker/checkouts/gecko/dom/base/nsGlobalWindowOuter.cpp:6475

    #0 0x7ff36b7cad39 in nsGlobalWindowOuter::LeaveModalState() /builds/worker/checkouts/gecko/dom/base/nsGlobalWindowOuter.cpp:6475:3
    #1 0x7ff36b7c448b in operator() /builds/worker/checkouts/gecko/dom/base/nsGlobalWindowOuter.cpp:5292:40
    #2 0x7ff36b7c448b in ~ScopeExit /builds/worker/workspace/obj-build/dist/include/mozilla/ScopeExit.h:106:7
    #3 0x7ff36b7c448b in nsGlobalWindowOuter::Print(nsIPrintSettings*, nsIWebProgressListener*, nsIDocShell*, nsGlobalWindowOuter::IsPreview, nsGlobalWindowOuter::IsForWindowDotPrint, std::function<void (mozilla::dom::PrintPreviewResultInfo const&)>&&, mozilla::ErrorResult&) /builds/worker/checkouts/gecko/dom/base/nsGlobalWindowOuter.cpp:5427:1
    #4 0x7ff36b795f8b in nsGlobalWindowInner::PrintPreview(nsIPrintSettings*, nsIWebProgressListener*, nsIDocShell*, mozilla::ErrorResult&) /builds/worker/checkouts/gecko/dom/base/nsGlobalWindowInner.cpp:3742:3
    #5 0x7ff36c68470b in mozilla::dom::Window_Binding::printPreview(JSContext*, JS::Handle<JSObject*>, void*, JSJitMethodCallArgs const&) /builds/worker/workspace/obj-build/dom/bindings/WindowBinding.cpp:3210:59
    #6 0x7ff36cbf5fa0 in bool mozilla::dom::binding_detail::GenericMethod<mozilla::dom::binding_detail::MaybeCrossOriginObjectThisPolicy, mozilla::dom::binding_detail::ThrowExceptions>(JSContext*, unsigned int, JS::Value*) /builds/worker/checkouts/gecko/dom/bindings/BindingUtils.cpp:3231:13
    #7 0x7ff36fbedd41 in CallJSNative(JSContext*, bool (*)(JSContext*, unsigned int, JS::Value*), js::CallReason, JS::CallArgs const&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:503:13
    #8 0x7ff36fbed60c in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:594:12
    #9 0x7ff36fbeed73 in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:647:10
    #10 0x7ff36fbe3262 in CallFromStack /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:651:10
    #11 0x7ff36fbe3262 in Interpret(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:3309:16
    #12 0x7ff36fbda378 in js::RunScript(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:473:13
    #13 0x7ff36fbed576 in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:619:13
    #14 0x7ff36fbeed73 in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:647:10
    #15 0x7ff36fbeefaf in js::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, js::AnyInvokeArgs const&, JS::MutableHandle<JS::Value>, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:664:8
    #16 0x7ff370193ecb in JS::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, JS::HandleValueArray const&, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/jsapi.cpp:2838:10
    #17 0x7ff36c925f6c in mozilla::dom::EventListener::HandleEvent(mozilla::dom::BindingCallContext&, JS::Handle<JS::Value>, mozilla::dom::Event&, mozilla::ErrorResult&) /builds/worker/workspace/obj-build/dom/bindings/EventListenerBinding.cpp:58:8
    #18 0x7ff36cf8f976 in void mozilla::dom::EventListener::HandleEvent<mozilla::dom::EventTarget*>(mozilla::dom::EventTarget* const&, mozilla::dom::Event&, mozilla::ErrorResult&, char const*, mozilla::dom::CallbackObject::ExceptionHandling, JS::Realm*) /builds/worker/workspace/obj-build/dist/include/mozilla/dom/EventListenerBinding.h:65:12
    #19 0x7ff36cf8f6bd in mozilla::EventListenerManager::HandleEventSubType(mozilla::EventListenerManager::Listener*, mozilla::dom::Event*, mozilla::dom::EventTarget*) /builds/worker/checkouts/gecko/dom/events/EventListenerManager.cpp:1074:43
    #20 0x7ff36cf90362 in mozilla::EventListenerManager::HandleEventInternal(nsPresContext*, mozilla::WidgetEvent*, mozilla::dom::Event**, mozilla::dom::EventTarget*, nsEventStatus*, bool) /builds/worker/checkouts/gecko/dom/events/EventListenerManager.cpp:1271:17
    #21 0x7ff36cf857c2 in HandleEvent /builds/worker/workspace/obj-build/dist/include/mozilla/EventListenerManager.h:354:5
    #22 0x7ff36cf857c2 in mozilla::EventTargetChainItem::HandleEvent(mozilla::EventChainPostVisitor&, mozilla::ELMCreationDetector&) /builds/worker/checkouts/gecko/dom/events/EventDispatcher.cpp:352:17
    #23 0x7ff36cf84d73 in mozilla::EventTargetChainItem::HandleEventTargetChain(nsTArray<mozilla::EventTargetChainItem>&, mozilla::EventChainPostVisitor&, mozilla::EventDispatchingCallback*, mozilla::ELMCreationDetector&) /builds/worker/checkouts/gecko/dom/events/EventDispatcher.cpp:554:16
    #24 0x7ff36cf878cd in mozilla::EventDispatcher::Dispatch(nsISupports*, nsPresContext*, mozilla::WidgetEvent*, mozilla::dom::Event*, nsEventStatus*, mozilla::EventDispatchingCallback*, nsTArray<mozilla::dom::EventTarget*>*) /builds/worker/checkouts/gecko/dom/events/EventDispatcher.cpp:1089:11
    #25 0x7ff36e602bf7 in nsDocumentViewer::PageHide(bool) /builds/worker/checkouts/gecko/layout/base/nsDocumentViewer.cpp:1433:5
    #26 0x7ff36f5a021d in nsDocShell::FirePageHideNotificationInternal(bool, bool) /builds/worker/checkouts/gecko/docshell/base/nsDocShell.cpp:1118:20
    #27 0x7ff36f59a130 in FirePageHideNotification /builds/worker/checkouts/gecko/docshell/base/nsDocShell.cpp:1102:3
    #28 0x7ff36f59a130 in nsDocShell::Destroy() /builds/worker/checkouts/gecko/docshell/base/nsDocShell.cpp:4419:9
    #29 0x7ff36ba0a417 in nsFrameLoader::DestroyDocShell() /builds/worker/checkouts/gecko/dom/base/nsFrameLoader.cpp:1989:20
    #30 0x7ff36ba0a327 in nsFrameLoaderDestroyRunnable::Run() /builds/worker/checkouts/gecko/dom/base/nsFrameLoader.cpp:1925:21
    #31 0x7ff36b8a6864 in mozilla::dom::Document::MaybeInitializeFinalizeFrameLoaders() /builds/worker/checkouts/gecko/dom/base/Document.cpp:8815:22
    #32 0x7ff36b911046 in applyImpl<mozilla::dom::Document, void (mozilla::dom::Document::*)()> /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:1148:12
    #33 0x7ff36b911046 in apply<mozilla::dom::Document, void (mozilla::dom::Document::*)()> /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:1154:12
    #34 0x7ff36b911046 in mozilla::detail::RunnableMethodImpl<mozilla::dom::Document*, void (mozilla::dom::Document::*)(), true, (mozilla::RunnableKind)0>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:1201:13
    #35 0x7ff36b741057 in nsContentUtils::RemoveScriptBlocker() /builds/worker/checkouts/gecko/dom/base/nsContentUtils.cpp:5581:15
    #36 0x7ff36b89f8e2 in mozilla::dom::Document::EndUpdate() /builds/worker/checkouts/gecko/dom/base/Document.cpp:7373:3
    #37 0x7ff36ba2019f in ~mozAutoDocUpdate /builds/worker/checkouts/gecko/dom/base/mozAutoDocUpdate.h:34:18
    #38 0x7ff36ba2019f in nsINode::RemoveChildNode(nsIContent*, bool) /builds/worker/checkouts/gecko/dom/base/nsINode.cpp:2105:1
    #39 0x7ff36ba1a4a4 in nsINode::RemoveChild(nsINode&, mozilla::ErrorResult&) /builds/worker/checkouts/gecko/dom/base/nsINode.cpp:807:3
    #40 0x7ff36bea8b45 in mozilla::dom::Node_Binding::removeChild(JSContext*, JS::Handle<JSObject*>, void*, JSJitMethodCallArgs const&) /builds/worker/workspace/obj-build/dom/bindings/NodeBinding.cpp:1132:60
    #41 0x7ff36cbf421a in bool mozilla::dom::binding_detail::GenericMethod<mozilla::dom::binding_detail::NormalThisPolicy, mozilla::dom::binding_detail::ThrowExceptions>(JSContext*, unsigned int, JS::Value*) /builds/worker/checkouts/gecko/dom/bindings/BindingUtils.cpp:3231:13
    #42 0x7ff36fbedd41 in CallJSNative(JSContext*, bool (*)(JSContext*, unsigned int, JS::Value*), js::CallReason, JS::CallArgs const&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:503:13
    #43 0x7ff36fbed60c in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:594:12
    #44 0x7ff36fbeed73 in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:647:10
    #45 0x7ff36fbe3262 in CallFromStack /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:651:10
    #46 0x7ff36fbe3262 in Interpret(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:3309:16
    #47 0x7ff36fbda378 in js::RunScript(JSContext*, js::RunState&) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:473:13
    #48 0x7ff36fbed576 in js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:619:13
    #49 0x7ff36fbeed73 in InternalCall(JSContext*, js::AnyInvokeArgs const&, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:647:10
    #50 0x7ff36fbeefaf in js::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, js::AnyInvokeArgs const&, JS::MutableHandle<JS::Value>, js::CallReason) /builds/worker/checkouts/gecko/js/src/vm/Interpreter.cpp:664:8
    #51 0x7ff370193ecb in JS::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, JS::HandleValueArray const&, JS::MutableHandle<JS::Value>) /builds/worker/checkouts/gecko/js/src/jsapi.cpp:2838:10
    #52 0x7ff36c99cb2d in mozilla::dom::Function::Call(mozilla::dom::BindingCallContext&, JS::Handle<JS::Value>, nsTArray<JS::Value> const&, JS::MutableHandle<JS::Value>, mozilla::ErrorResult&) /builds/worker/workspace/obj-build/dom/bindings/FunctionBinding.cpp:46:8
    #53 0x7ff36b9958ac in void mozilla::dom::Function::Call<nsCOMPtr<nsIGlobalObject> >(nsCOMPtr<nsIGlobalObject> const&, nsTArray<JS::Value> const&, JS::MutableHandle<JS::Value>, mozilla::ErrorResult&, char const*, mozilla::dom::CallbackObject::ExceptionHandling, JS::Realm*) /builds/worker/workspace/obj-build/dist/include/mozilla/dom/FunctionBinding.h:72:12
    #54 0x7ff36b995588 in mozilla::dom::CallbackTimeoutHandler::Call(char const*) /builds/worker/checkouts/gecko/dom/base/TimeoutHandler.cpp:167:29
    #55 0x7ff36b7a1032 in nsGlobalWindowInner::RunTimeoutHandler(mozilla::dom::Timeout*, nsIScriptContext*) /builds/worker/checkouts/gecko/dom/base/nsGlobalWindowInner.cpp:6214:38
    #56 0x7ff36b992c02 in mozilla::dom::TimeoutManager::RunTimeout(mozilla::TimeStamp const&, mozilla::TimeStamp const&, bool) /builds/worker/checkouts/gecko/dom/base/TimeoutManager.cpp:896:44
    #57 0x7ff36b992294 in mozilla::dom::TimeoutExecutor::MaybeExecute() /builds/worker/checkouts/gecko/dom/base/TimeoutExecutor.cpp:179:11
    #58 0x7ff36b993f12 in Notify /builds/worker/checkouts/gecko/dom/base/TimeoutExecutor.cpp:246:5
    #59 0x7ff36b993f12 in non-virtual thunk to mozilla::dom::TimeoutExecutor::Notify(nsITimer*) /builds/worker/checkouts/gecko/dom/base/TimeoutExecutor.cpp
    #60 0x7ff369cd259c in nsTimerImpl::Fire(int) /builds/worker/checkouts/gecko/xpcom/threads/nsTimerImpl.cpp:565:39
    #61 0x7ff369cd2218 in nsTimerEvent::Run() /builds/worker/checkouts/gecko/xpcom/threads/TimerThread.cpp:251:11
    #62 0x7ff369cf266c in mozilla::ThrottledEventQueue::Inner::ExecuteRunnable() /builds/worker/checkouts/gecko/xpcom/threads/ThrottledEventQueue.cpp:254:22
    #63 0x7ff369cedb91 in mozilla::ThrottledEventQueue::Inner::Executor::Run() /builds/worker/checkouts/gecko/xpcom/threads/ThrottledEventQueue.cpp:81:15
    #64 0x7ff369cc755f in mozilla::RunnableTask::Run() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:452:16
    #65 0x7ff369cc5baa in mozilla::TaskController::DoExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:732:26
    #66 0x7ff369cc4c54 in mozilla::TaskController::ExecuteNextTaskOnlyMainThreadInternal(mozilla::detail::BaseAutoLock<mozilla::Mutex&> const&) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:591:15
    #67 0x7ff369cc4e07 in mozilla::TaskController::ProcessPendingMTTask(bool) /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:375:36
    #68 0x7ff369ccaeb9 in operator() /builds/worker/checkouts/gecko/xpcom/threads/TaskController.cpp:125:37
    #69 0x7ff369ccaeb9 in mozilla::detail::RunnableFunction<mozilla::TaskController::InitializeInternal()::$_4>::Run() /builds/worker/workspace/obj-build/dist/include/nsThreadUtils.h:534:5
    #70 0x7ff369cdc3f5 in nsThread::ProcessNextEvent(bool, bool*) /builds/worker/checkouts/gecko/xpcom/threads/nsThread.cpp:1200:14
    #71 0x7ff369ce24aa in NS_ProcessNextEvent(nsIThread*, bool) /builds/worker/checkouts/gecko/xpcom/threads/nsThreadUtils.cpp:548:10
    #72 0x7ff36a5e45b4 in mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) /builds/worker/checkouts/gecko/ipc/glue/MessagePump.cpp:109:5
    #73 0x7ff36a550b23 in MessageLoop::RunInternal() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:334:10
    #74 0x7ff36a550a3d in RunHandler /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:327:3
    #75 0x7ff36a550a3d in MessageLoop::Run() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:309:3
    #76 0x7ff36e2b8ac8 in nsBaseAppShell::Run() /builds/worker/checkouts/gecko/widget/nsBaseAppShell.cpp:137:27
    #77 0x7ff36fab3063 in XRE_RunAppShell() /builds/worker/checkouts/gecko/toolkit/xre/nsEmbedFunctions.cpp:902:20
    #78 0x7ff36a5e54e9 in mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) /builds/worker/checkouts/gecko/ipc/glue/MessagePump.cpp:237:9
    #79 0x7ff36a550b23 in MessageLoop::RunInternal() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:334:10
    #80 0x7ff36a550a3d in RunHandler /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:327:3
    #81 0x7ff36a550a3d in MessageLoop::Run() /builds/worker/checkouts/gecko/ipc/chromium/src/base/message_loop.cc:309:3
    #82 0x7ff36fab2c48 in XRE_InitChildProcess(int, char**, XREChildData const*) /builds/worker/checkouts/gecko/toolkit/xre/nsEmbedFunctions.cpp:733:34
    #83 0x563331f4fd87 in content_process_main /builds/worker/checkouts/gecko/browser/app/../../ipc/contentproc/plugin-container.cpp:57:28
    #84 0x563331f4fd87 in main /builds/worker/checkouts/gecko/browser/app/nsBrowserApp.cpp:305:18
    #85 0x7ff37e2680b2 in __libc_start_main /build/glibc-ZN95T4/glibc-2.31/csu/../csu/libc-start.c:308:16

It seems that it hit MOZ_ASSERT(IsSuspended());[1] in printPreview()[2] while frame was unloaded. Perhaps Emilio can shed some light here.

[1] https://searchfox.org/mozilla-central/rev/4415bec7a49c50a338167d9c8934527b9cae59d0/dom/base/nsGlobalWindowOuter.cpp#6475
[2] https://searchfox.org/mozilla-central/rev/4415bec7a49c50a338167d9c8934527b9cae59d0/dom/base/nsGlobalWindowOuter.cpp#5292

Bugmon Analysis:
Verified bug as reproducible on mozilla-central 20201211213049-1130661c79c2.
Failed to bisect testcase (Unable to launch the end build!):

Start: a6b449010a04a134102052a08639a51b13f576d2 (20191214021830)
End: 7b5facb4df3a77bd60d21045be212161c91cea12 (20201210034702)
BuildFlags: BuildFlags(asan=False, tsan=False, debug=True, fuzzing=True, coverage=False, valgrind=False)

Bugmon Analysis
The bug appears to have been fixed in the following build range:

Start: 95ca19ef6eb3c0407b824fcf711735cca64095e1 (20210312163838)
End: a162279140c6aeb98e2825019cc67ba99be3d40c (20210312170532)
Pushlog: https://hg.mozilla.org/integration/autoland/pushloghtml?fromchange=95ca19ef6eb3c0407b824fcf711735cca64095e1&tochange=a162279140c6aeb98e2825019cc67ba99be3d40c
Removing bugmon keyword as no further action possible. Please review the bug and re-add the keyword for further analysis.

:edgar, is it possible that this was fixed via bug 1640766?

Yeah, sounds pretty likely, thanks Jason!