This looks like a deadlock associated with async instantiation, but for that to happen, I would have expected the chrome main thread to be wrapped up in IPC code. Bill, are we missing some context here on the chrome thread? Maybe the hang detector breaks us out of whatever we were hung up in? https://developer.mozilla.org/en-US/docs/NPP_New 1924bbb7-ead9-4e0c-9ac5-c1c2c2150425 Windows 8.0, 6.2.9200 NPSWF32_17_0_0_169.dll PLUGIN ----------------------------------------------------------------------------------- 0 KiFastSystemCallRet 1 NtWaitForMultipleObjects 2 InterlockedIncrement 3 NtUserScrollDC 4 MsgWaitForMultipleObjects 5 F_1152915508___________________________________ 6 F2166389_____________________________________________________________________ 7 F_917831355____________________________________________ 8 F1315696776________________________________ 9 F_1428703866________________________________ 10 F845925699_____________________________________ 11 F15952908_________________________________________________________ 12 F1601322143_______________________________________________________________ 13 mozilla::plugins::PluginInstanceChild::DoNPP_New() src 14 mozilla::plugins::PluginModuleChild::AnswerSyncNPP_New(mozilla::plugins::PPluginInstanceChild *,short *) src 15 mozilla::plugins::PPluginModuleChild::OnCallReceived(IPC::Message const &,IPC::Message * &) src 16 mozilla::ipc::MessageChannel::DispatchInterruptMessage(IPC::Message const &,unsigned int) src 17 mozilla::ipc::MessageChannel::OnMaybeDequeueOne() src 18 MessageLoop::DoWork() src 19 base::MessagePumpForUI::DoRunLoop() src 20 base::MessagePumpWin::RunWithDispatcher(base::MessagePump::Delegate *,base::MessagePumpWin::Dispatcher *) src 21 base::MessagePumpWin::Run(base::MessagePump::Delegate *) src 22 MessageLoop::RunInternal() src 23 MessageLoop::RunHandler() src 24 MessageLoop::Run() src 25 XRE_InitChildProcess src 26 content_process_main(int,char * * const) src 27 wmain src 28 __tmainCRTStartup 29 BaseThreadInitThunk 30 LdrpAllocateTls 31 LdrpAllocateTls CONTENT ----------------------------------------------------------------------------------- 0 KiFastSystemCallRet 1 ZwWaitForSingleObject 2 WaitForSingleObjectEx 3 WaitForSingleObject 4 PR_WaitCondVar src 5 mozilla::CondVar::Wait(unsigned int) src 6 mozilla::ipc::MessageChannel::WaitForSyncNotify() src 7 mozilla::ipc::MessageChannel::Send(IPC::Message *,IPC::Message *) src 8 mozilla::dom::PBrowserChild::SendGetTabOffset(mozilla::gfx::IntPointTyped<mozilla::LayoutDevicePixel> *) src 9 nsPluginFrame::GetRemoteTabChromeOffset() src 10 nsPluginFrame::CallSetWindow(bool) src 11 nsPluginInstanceOwner::CallSetWindow() src 12 nsPluginHost::InstantiatePluginInstance(nsACString_internal const &,nsIURI *,nsObjectLoadingContent *,nsPluginInstanceOwner * *) src 13 nsObjectLoadingContent::InstantiatePluginInstance(bool) src 14 nsObjectLoadingContent::SyncStartPluginInstance() src 15 nsObjectLoadingContent::ScriptRequestPluginInstance(JSContext *,nsNPAPIPluginInstance * *) src 16 nsObjectLoadingContent::DoResolve(JSContext *,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JSPropertyDescriptor>) src 17 mozilla::dom::HTMLObjectElementBinding::_resolve src 18 js::GetProperty(JSContext *,JS::Handle<JSObject *>,JS::Handle<JSObject *>,JS::Handle<jsid>,JS::MutableHandle<JS::Value>) src 19 GetPropertyOperation src 20 Interpret src 21 js::RunScript(JSContext *,js::RunState &) src 22 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 23 js::fun_apply(JSContext *,unsigned int,JS::Value *) src 24 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 25 Interpret src 26 js::RunScript(JSContext *,js::RunState &) src 27 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 28 js::Invoke(JSContext *,JS::Value const &,JS::Value const &,unsigned int,JS::Value const *,JS::MutableHandle<JS::Value>) src 29 JS::Call(JSContext *,JS::Handle<JS::Value>,JS::Handle<JS::Value>,JS::HandleValueArray const &,JS::MutableHandle<JS::Value>) src 30 mozilla::dom::Function::Call(JSContext *,JS::Handle<JS::Value>,nsTArray<JS::Value> const &,JS::MutableHandle<JS::Value>,mozilla::ErrorResult &) src 31 mozilla::dom::Function::Call<nsCOMPtr<nsISupports> >(nsCOMPtr<nsISupports> const &,nsTArray<JS::Value> const &,JS::MutableHandle<JS::Value>,mozilla::ErrorResult &,char const *,mozilla::dom::CallbackObject::ExceptionHandling,JSCompartment *) src 32 nsGlobalWindow::RunTimeoutHandler(nsTimeout *,nsIScriptContext *) src 33 nsGlobalWindow::RunTimeout(nsTimeout *) src 34 nsGlobalWindow::TimerCallback(nsITimer *,void *) src 35 nsTimerImpl::Fire() src 36 nsTimerEvent::Run() src 37 nsThread::ProcessNextEvent(bool,bool *) src 38 mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate *) src 39 mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate *) src 40 MessageLoop::RunHandler() src 41 MessageLoop::Run() src 42 nsBaseAppShell::Run() src 43 nsAppShell::Run() src 44 XRE_RunAppShell src 45 mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate *) src 46 MessageLoop::RunHandler() src 47 MessageLoop::Run() src 48 XRE_InitChildProcess src 49 content_process_main(int,char * * const) src 50 wmain src 51 __tmainCRTStartup 52 BaseThreadInitThunk 53 LdrpAllocateTls 54 LdrpAllocateTls BROWSER ----------------------------------------------------------------------------------- 0 google_breakpad::ExceptionHandler::WriteMinidump(std::basic_string<wchar_t,std::char_traits<wchar_t>,std::allocator<wchar_t> > const &,bool (*)(wchar_t const *,wchar_t const *,void *,_EXCEPTION_POINTERS *,MDRawAssertionInfo *,bool),void *) src 1 CrashReporter::CreatePairedMinidumps(void *,unsigned long,nsIFile * *) src 2 mozilla::dom::CrashReporterParent::GeneratePairedMinidump<mozilla::plugins::PluginModuleChromeParent>(mozilla::plugins::PluginModuleChromeParent *) src 3 mozilla::plugins::PluginModuleChromeParent::TerminateChildProcess(MessageLoop *) src 4 mozilla::plugins::TerminatePlugin(unsigned int) src 5 `anonymous namespace'::HangMonitoredProcess::TerminatePlugin() src 6 NS_InvokeByIndex src 7 XPC_WN_CallMethod(JSContext *,unsigned int,JS::Value *) src 8 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 9 Interpret src 10 js::RunScript(JSContext *,js::RunState &) src 11 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 12 Interpret src 13 js::RunScript(JSContext *,js::RunState &) src 14 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 15 js::CrossCompartmentWrapper::call(JSContext *,JS::Handle<JSObject *>,JS::CallArgs const &) src 16 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 17 Interpret src 18 js::RunScript(JSContext *,js::RunState &) src 19 js::Invoke(JSContext *,JS::CallArgs,js::MaybeConstruct) src 20 js::Invoke(JSContext *,JS::Value const &,JS::Value const &,unsigned int,JS::Value const *,JS::MutableHandle<JS::Value>) src 21 mozilla::dom::EventHandlerNonNull::Call(JSContext *,JS::Handle<JS::Value>,mozilla::dom::Event &,JS::MutableHandle<JS::Value>,mozilla::ErrorResult &) src 22 mozilla::dom::EventHandlerNonNull::Call<nsISupports *>(nsISupports * const &,mozilla::dom::Event &,JS::MutableHandle<JS::Value>,mozilla::ErrorResult &,char const *,mozilla::dom::CallbackObject::ExceptionHandling,JSCompartment *) src 23 mozilla::JSEventHandler::HandleEvent(nsIDOMEvent *) src 24 mozilla::EventListenerManager::HandleEventInternal(nsPresContext *,mozilla::WidgetEvent *,nsIDOMEvent * *,mozilla::dom::EventTarget *,nsEventStatus *) src 25 mozilla::EventTargetChainItem::HandleEventTargetChain(nsTArray<mozilla::EventTargetChainItem> &,mozilla::EventChainPostVisitor &,mozilla::EventDispatchingCallback *,mozilla::ELMCreationDetector &) src 26 mozilla::EventDispatcher::Dispatch(nsISupports *,nsPresContext *,mozilla::WidgetEvent *,nsIDOMEvent *,nsEventStatus *,mozilla::EventDispatchingCallback *,nsTArray<mozilla::dom::EventTarget *> *) src 27 mozilla::EventDispatcher::DispatchDOMEvent(nsISupports *,mozilla::WidgetEvent *,nsIDOMEvent *,nsPresContext *,nsEventStatus *) src 28 PresShell::HandleDOMEventWithTarget(nsIContent *,nsIDOMEvent *,nsEventStatus *) src 29 nsContentUtils::DispatchXULCommand(nsIContent *,bool,nsIDOMEvent *,nsIPresShell *,bool,bool,bool,bool) src 30 nsXULMenuCommandEvent::Run() src 31 nsThread::ProcessNextEvent(bool,bool *) src 32 mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate *) src 33 MessageLoop::RunHandler() src 34 MessageLoop::Run() src 35 nsBaseAppShell::Run() src 36 nsAppShell::Run() src 37 nsAppStartup::Run() src 38 XREMain::XRE_mainRun() src 39 XREMain::XRE_main(int,char * * const,nsXREAppData const *) src 40 XRE_main src 41 do_main src 42 NS_internal_main(int,char * *) src 43 wmain src 44 __tmainCRTStartup 45 BaseThreadInitThunk 46 LdrpAllocateTls 47 LdrpAllocateTls

Another mystery: how the plugin process ended up in PluginModuleChild::AnswerSyncNPP_New() yet the content process isn't in mozilla::plugins::PPluginModuleParent::CallSyncNPP_New().

Sorry, nothing is popping out at me here. I'll explain the way the timeout happens in case it helps. 1. Some sync plugin message takes too long to get a response. The IPC code calls PluginModuleContentParent::ShouldContinueFromReplyTimeout, which tells the hang monitor code about the hang. We don't actually time out the IPC message though--we keep waiting. 2. The hang monitor code sends a message to the chrome process on a separate thread. The chrome process cancels any ongoing CPOW and puts up the hang UI. 3. The user selects the menu option to kill the plugin. We take minidumps of all three processes and then kill the plugin process. To give more direct answers to Jim's questions: - Although the hang monitor cancels CPOWs, there is a delay between then and when it kills the plugin. The delay is however long it takes the user to mouse over and select the "Terminate Plugin" menu options. Presumably that's enough time for the chrome process to respond to whatever message is deadlocking us. So the fact that we still appear to be deadlocked when we take the minidumps suggests that the hang did not involve the chrome process. - I agree that it's strange that we don't see CallSyncNPP_New in the stacks anywhere. The hang monitor doesn't do anything to cancel IPCs except for its final act of killing the plugin process, which hasn't happened yet at the time we take the minidumps.

Jim, have you seen this more recently?

nope.