###!!! ASSERTION: This is unsafe! Fix the caller!: 'Error', file e:/builds/moz2_slave/m-cen-w32-dbg/build/content/events/src/nsEventDispatcher.cpp, line 549 I get this just starting up Firefox on Windows, with a fresh profile. It also shows up on Tinderbox, at least for Mochitest: http://tinderbox.mozilla.org/showlog.cgi?log=Firefox/1310671623.1310672885.22199.gz&fulltext=1

Ha, I was wondering if I was the only one seeing this locally!

Does anyone have a stack trace for this?

> xul.dll!RealBreak() Line 422 C++ xul.dll!Break(const char * aMsg=0x00159274) Line 521 C++ xul.dll!NS_DebugBreak_P(unsigned int aSeverity=0x00000001, const char * aStr=0x5ec0ad18, const char * aExpr=0x5ec0ad10, const char * aFile=0x5ec0acd0, int aLine=0x00000225) Line 380 + 0xc bytes C++ xul.dll!nsEventDispatcher::Dispatch(nsISupports * aTarget=0x05204128, nsPresContext * aPresContext=0x05f03fd8, nsEvent * aEvent=0x0921f9b0, nsIDOMEvent * aDOMEvent=0x0921f940, nsEventStatus * aEventStatus=0x0015984c, nsDispatchingCallback * aCallback=0x00000000, nsCOMArray<nsIDOMEventTarget> * aTargets=0x00000000) Line 549 + 0x1b bytes C++ xul.dll!nsEventDispatcher::DispatchDOMEvent(nsISupports * aTarget=0x05204128, nsEvent * aEvent=0x00000000, nsIDOMEvent * aDOMEvent=0x0921f940, nsPresContext * aPresContext=0x05f03fd8, nsEventStatus * aEventStatus=0x0015984c) Line 735 + 0x1d bytes C++ xul.dll!nsGlobalWindow::DispatchEvent(nsIDOMEvent * aEvent=0x0921f940, int * aRetVal=0x00159900) Line 7275 + 0x24 bytes C++ xul.dll!nsGlobalWindow::DispatchEvent(nsIDOMEvent * aEvent=0x0921f940, int * aRetVal=0x00159900) Line 7258 + 0x61 bytes C++ xul.dll!nsContentUtils::DispatchTrustedEvent(nsIDocument * aDoc=0x05ee7fb0, nsISupports * aTarget=0x05204178, const nsAString_internal & aEventName={...}, int aCanBubble=0x00000001, int aCancelable=0x00000001, int * aDefaultAction=0x00159900) Line 3034 + 0x3a bytes C++ xul.dll!nsGlobalWindow::DispatchCustomEvent(const char * aEventName=0x5f022eec) Line 4309 + 0x57 bytes C++ xul.dll!nsWebShellWindow::HandleEvent(nsGUIEvent * aEvent=0x00159b30) Line 401 C++ xul.dll!nsWindow::DispatchEvent(nsGUIEvent * event=0x00159b30, nsEventStatus & aStatus=nsEventStatus_eIgnore) Line 3542 + 0xc bytes C++ xul.dll!nsWindow::DispatchWindowEvent(nsGUIEvent * event=0x00159b30) Line 3573 C++ xul.dll!nsWindow::OnWindowPosChanged(tagWINDOWPOS * wp=0x0015a3f8, int & result=0x00000000) Line 5989 + 0x1a bytes C++ xul.dll!nsWindow::ProcessMessage(unsigned int msg=0x00000047, unsigned int & wParam=0x00000000, long & lParam=0x0015a3f8, long * aRetValue=0x0015a21c) Line 5203 C++ xul.dll!nsWindow::WindowProcInternal(HWND__ * hWnd=0x00080580, unsigned int msg=0x00000047, unsigned int wParam=0x00000000, long lParam=0x0015a3f8) Line 4403 + 0x20 bytes C++ xul.dll!CallWindowProcCrashProtected(long (HWND__ *, unsigned int, unsigned int, long)* wndProc=0x5e1e9530, HWND__ * hWnd=0x00080580, unsigned int msg=0x00000047, unsigned int wParam=0x00000000, long lParam=0x0015a3f8) Line 65 + 0x13 bytes C++ xul.dll!nsWindow::WindowProc(HWND__ * hWnd=0x00080580, unsigned int msg=0x00000047, unsigned int wParam=0x00000000, long lParam=0x0015a3f8) Line 4345 + 0x1a bytes C++ user32.dll!_InternalCallWinProc@20() + 0x23 bytes user32.dll!_UserCallWinProcCheckWow@32() + 0x693 bytes user32.dll!_DispatchClientMessage@24() + 0x51 bytes user32.dll!___fnINLPWINDOWPOS@4() + 0x2c bytes ntdll.dll!_KiUserCallbackDispatcher@12() + 0x2e bytes user32.dll!_NtUserSetWindowPos@28() + 0x15 bytes xul.dll!nsWindow::ResetLayout() Line 1997 C++ xul.dll!nsWindow::UpdateNonClientMargins(int aSizeMode=0x00000000, int aReflowWindow=0x00000001) Line 2138 C++ xul.dll!nsWindow::SetNonClientMargins(nsIntMargin & margins={...}) Line 2167 + 0xc bytes C++ xul.dll!nsXULElement::SetChromeMargins(const nsAString_internal * aValue=0x0015a9a0) Line 2469 C++ xul.dll!nsXULElement::AfterSetAttr(int aNamespaceID=0x00000000, nsIAtom * aName=0x03b26ce0, const nsAString_internal * aValue=0x0015a9a0, int aNotify=0x00000001) Line 1164 C++ xul.dll!nsGenericElement::SetAttrAndNotify(int aNamespaceID=0x00000000, nsIAtom * aName=0x03b26ce0, nsIAtom * aPrefix=0x00000000, const nsAString_internal & aOldValue={...}, nsAttrValue & aParsedValue={...}, unsigned char aModType='', int aFireMutation=0x00000000, int aNotify=0x00000001, const nsAString_internal * aValueForAfterSetAttr=0x0015a9a0) Line 4537 + 0x26 bytes C++ xul.dll!nsGenericElement::SetAttr(int aNamespaceID=0x00000000, nsIAtom * aName=0x03b26ce0, nsIAtom * aPrefix=0x00000000, const nsAString_internal & aValue={...}, int aNotify=0x00000001) Line 4436 + 0x39 bytes C++ xul.dll!nsGenericElement::SetAttr(int aNameSpaceID=0x00000000, nsIAtom * aName=0x03b26ce0, const nsAString_internal & aValue={...}, int aNotify=0x00000001) Line 284 C++ xul.dll!nsGenericElement::SetAttribute(const nsAString_internal & aName={...}, const nsAString_internal & aValue={...}) Line 2418 + 0x19 bytes C++ xul.dll!nsXULElement::SetAttribute(const nsAString_internal & name={...}, const nsAString_internal & value={...}) Line 563 + 0x14 bytes C++ xul.dll!nsIDOMElement_SetAttribute(JSContext * cx=0x052043e8, unsigned int argc=0x00000002, jsval_layout * vp=0x04830128) Line 5619 + 0x23 bytes C++ mozjs.dll!js::CallJSNative(JSContext * cx=0x052043e8, int (JSContext *, unsigned int, js::Value *)* native=0x5deaeb30, const js::CallArgs & args={...}) Line 284 + 0x19 bytes C++ mozjs.dll!js::Invoke(JSContext * cx=0x052043e8, const js::CallArgs & argsRef={...}, js::MaybeConstruct construct=NO_CONSTRUCT) Line 656 + 0x14 bytes C++ mozjs.dll!js::Interpret(JSContext * cx=0x052043e8, js::StackFrame * entryFrame=0x04830058, js::InterpMode interpMode=JSINTERP_NORMAL) Line 4084 + 0x12 bytes C++ mozjs.dll!js::RunScript(JSContext * cx=0x052043e8, JSScript * script=0x05f22e70, js::StackFrame * fp=0x04830058) Line 613 + 0xf bytes C++ mozjs.dll!js::Invoke(JSContext * cx=0x052043e8, const js::CallArgs & argsRef={...}, js::MaybeConstruct construct=NO_CONSTRUCT) Line 686 + 0x11 bytes C++ mozjs.dll!js::Invoke(JSContext * cx=0x052043e8, js::InvokeArgsGuard & args={...}, js::MaybeConstruct construct=NO_CONSTRUCT) Line 169 + 0x1a bytes C++ mozjs.dll!js::ExternalInvoke(JSContext * cx=0x052043e8, const js::Value & thisv={...}, const js::Value & fval={...}, unsigned int argc=0x00000001, js::Value * argv=0x08f626c0, js::Value * rval=0x0015bd94) Line 805 + 0xf bytes C++ mozjs.dll!JS_CallFunctionValue(JSContext * cx=0x052043e8, JSObject * obj=0x04dc5e98, jsval_layout fval={...}, unsigned int argc=0x00000001, jsval_layout * argv=0x08f626c0, jsval_layout * rval=0x0015bd94) Line 5063 + 0x45 bytes C++ xul.dll!nsJSContext::CallEventHandler(nsISupports * aTarget=0x05232f80, void * aScope=0x04dc5e98, void * aHandler=0x053489a8, nsIArray * aargv=0x0522e558, nsIVariant * * arv=0x0015bfd0) Line 1907 + 0x2e bytes C++ xul.dll!nsJSEventListener::HandleEvent(nsIDOMEvent * aEvent=0x06258da0) Line 224 + 0x64 bytes C++ xul.dll!nsEventListenerManager::HandleEventSubType(nsListenerStruct * aListenerStruct=0x06492ea0, nsIDOMEventListener * aListener=0x05f21228, nsIDOMEvent * aDOMEvent=0x06258da0, nsIDOMEventTarget * aCurrentTarget=0x05232f8c, unsigned int aPhaseFlags=0x00000006, nsCxPusher * aPusher=0x0015c36c) Line 1080 + 0x12 bytes C++ xul.dll!nsEventListenerManager::HandleEventInternal(nsPresContext * aPresContext=0x05f03fd8, nsEvent * aEvent=0x0015c474, nsIDOMEvent * * aDOMEvent=0x0015c35c, nsIDOMEventTarget * aCurrentTarget=0x05232f8c, unsigned int aFlags=0x00000006, nsEventStatus * aEventStatus=0x0015c360, nsCxPusher * aPusher=0x0015c36c) Line 1179 + 0x27 bytes C++ xul.dll!nsEventListenerManager::HandleEvent(nsPresContext * aPresContext=0x05f03fd8, nsEvent * aEvent=0x0015c474, nsIDOMEvent * * aDOMEvent=0x0015c35c, nsIDOMEventTarget * aCurrentTarget=0x05232f8c, unsigned int aFlags=0x00000006, nsEventStatus * aEventStatus=0x0015c360, nsCxPusher * aPusher=0x0015c36c) Line 156 C++ xul.dll!nsEventTargetChainItem::HandleEvent(nsEventChainPostVisitor & aVisitor={...}, unsigned int aFlags=0x00000006, int aMayHaveNewListenerManagers=0x00000000, nsCxPusher * aPusher=0x0015c36c) Line 216 C++ xul.dll!nsEventTargetChainItem::HandleEventTargetChain(nsEventChainPostVisitor & aVisitor={...}, unsigned int aFlags=0x00000006, nsDispatchingCallback * aCallback=0x00000000, int aMayHaveNewListenerManagers=0x00000000, nsCxPusher * aPusher=0x0015c36c) Line 346 C++ xul.dll!nsEventDispatcher::Dispatch(nsISupports * aTarget=0x05204128, nsPresContext * aPresContext=0x05f03fd8, nsEvent * aEvent=0x0015c474, nsIDOMEvent * aDOMEvent=0x00000000, nsEventStatus * aEventStatus=0x0015c470, nsDispatchingCallback * aCallback=0x00000000, nsCOMArray<nsIDOMEventTarget> * aTargets=0x00000000) Line 672 + 0x21 bytes C++ xul.dll!DocumentViewerImpl::LoadComplete(unsigned int aStatus=0x00000000) Line 1067 + 0x23 bytes C++ xul.dll!nsDocShell::EndPageLoad(nsIWebProgress * aProgress=0x05202fdc, nsIChannel * aChannel=0x052e0d38, unsigned int aStatus=0x00000000) Line 6162 C++ xul.dll!nsDocShell::OnStateChange(nsIWebProgress * aProgress=0x05202fdc, nsIRequest * aRequest=0x052e0d38, unsigned int aStateFlags=0x00020010, unsigned int aStatus=0x00000000) Line 5998 C++ xul.dll!nsDocLoader::FireOnStateChange(nsIWebProgress * aProgress=0x05202fdc, nsIRequest * aRequest=0x052e0d38, int aStateFlags=0x00020010, unsigned int aStatus=0x00000000) Line 1340 C++ xul.dll!nsDocLoader::doStopDocumentLoad(nsIRequest * request=0x052e0d38, unsigned int aStatus=0x00000000) Line 958 C++ xul.dll!nsDocLoader::DocLoaderIsEmpty(int aFlushLayout=0x00000001) Line 825 C++ xul.dll!nsDocLoader::ChildDoneWithOnload(nsIDocumentLoader * aChild=0x06629c00) Line 205 C++ xul.dll!nsDocLoader::DocLoaderIsEmpty(int aFlushLayout=0x00000001) Line 829 C++ xul.dll!nsDocLoader::OnStopRequest(nsIRequest * aRequest=0x091d1fd8, nsISupports * aCtxt=0x00000000, unsigned int aStatus=0x00000000) Line 710 C++ xul.dll!nsLoadGroup::RemoveRequest(nsIRequest * request=0x091d1fd8, nsISupports * ctxt=0x00000000, unsigned int aStatus=0x00000000) Line 734 + 0x31 bytes C++ xul.dll!nsDocument::DoUnblockOnload() Line 7218 C++ xul.dll!nsDocument::UnblockOnload(int aFireSync=0x00000001) Line 7159 C++ xul.dll!nsDocument::DispatchContentLoadedEvents() Line 4205 C++ xul.dll!nsRunnableMethodImpl<void (__thiscall nsDocument::*)(void),1>::Run() Line 342 C++ xul.dll!nsThread::ProcessNextEvent(int mayWait=0x00000000, int * result=0x0015cec4) Line 617 + 0x19 bytes C++ xul.dll!NS_ProcessNextEvent_P(nsIThread * thread=0x00919188, int mayWait=0x00000000) Line 245 + 0x16 bytes C++ xul.dll!mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate * aDelegate=0x009149d0) Line 110 + 0xe bytes C++ xul.dll!MessageLoop::RunInternal() Line 219 C++ xul.dll!MessageLoop::RunHandler() Line 203 C++ xul.dll!MessageLoop::Run() Line 177 C++ xul.dll!nsBaseAppShell::Run() Line 191 C++ xul.dll!nsAppShell::Run() Line 256 + 0x9 bytes C++ xul.dll!nsAppStartup::Run() Line 222 + 0x1c bytes C++ xul.dll!XRE_main(int argc=0x00000004, char * * argv=0x00297578, const nsXREAppData * aAppData=0x0029e778) Line 3577 + 0x25 bytes C++ firefox.exe!do_main(const char * exePath=0x0015f834, int argc=0x00000004, char * * argv=0x00297578) Line 198 + 0x12 bytes C++ firefox.exe!NS_internal_main(int argc=0x00000004, char * * argv=0x00297578) Line 281 + 0x14 bytes C++ firefox.exe!wmain(int argc=0x00000004, wchar_t * * argv=0x00291cc0) Line 107 + 0xd bytes C++ firefox.exe!__tmainCRTStartup() Line 552 + 0x19 bytes C firefox.exe!wmainCRTStartup() Line 371 C kernel32.dll!@BaseThreadInitThunk@12() + 0x12 bytes ntdll.dll!___RtlUserThreadStart@8() + 0x27 bytes ntdll.dll!__RtlUserThreadStart@8() + 0x1b bytes

The interesting part starts from nsXULElement::AfterSetAttr. Somehow setting margins makes windows to process next message. I think bz' changes to nsGlobalWindow::DispatchCustomEvent may have somehow caused this to become visible, but I believe the bug has been there for a long time. The right fix for this could be to make nsXULElement::AfterSetAttr do things in a script runner.

> I think bz' changes to nsGlobalWindow::DispatchCustomEvent may have > somehow caused this to become visible What caused this to become visible is that we now fire a DOM sizemodechange event when we get an NS_SIZEMODE event passed to nsWebShellWindow. This was added in bug 648045. I'm not sure whether it's safer to do that event dispatch off a script runner or to make the SetNonClientMargins call off a script runner.... The former would sort of restore the (unsafe, agreed) status quo ante, while the latter would have a slightly higher regression risk. It doesn't help that I don't have an up to date Windows build right now; does someone who has one want to take this?

Comment on attachment 550178 [details] [diff] [review] Set chrome margins off a scriptrunner. >+class MarginSetter : public nsRunnable { { should be in the next line

Did that.