It's a low volume crash, but as bug 566489 landed in 14.0 an it occurs in the trunk, I think it deserves a bug. Signature nsAutoCompleteController::ProcessResult(int, nsIAutoCompleteResult*) More Reports Search UUID c8080668-183c-470d-9150-e990b2120520 Date Processed 2012-05-20 02:53:57 Uptime 27 Last Crash 35 seconds before submission Install Age 15.8 minutes since version was first installed. Install Time 2012-05-20 02:38:07 Product Firefox Version 15.0a1 Build ID 20120519030527 Release Channel nightly OS Windows NT OS Version 6.1.7601 Service Pack 1 Build Architecture amd64 Build Architecture Info family 6 model 15 stepping 13 Crash Reason EXCEPTION_ILLEGAL_INSTRUCTION Crash Address 0x7feebff7790 App Notes AdapterVendorID: 0x10de, AdapterDeviceID: 0x0427, AdapterSubsysID: 01f21028, AdapterDriverVersion: 8.17.12.9573 D2D? D2D+ DWrite? DWrite+ D3D10 Layers? D3D10 Layers+ EMCheckCompatibility True Total Virtual Memory 8796092891136 Available Virtual Memory 8795094216704 System Memory Use Percentage 59 Available Page File 4774514688 Available Physical Memory 1730129920 Frame Module Signature Source 0 xul.dll nsAutoCompleteController::ProcessResult toolkit/components/autocomplete/nsAutoCompleteController.cpp:1307 1 xul.dll nsAutoCompleteController::OnSearchResult toolkit/components/autocomplete/nsAutoCompleteController.cpp:722 2 xul.dll XPTC__InvokebyIndex xpcom/reflect/xptcall/src/md/win32/xptcinvoke_asm_x86_64.asm:90 3 xul.dll XPTC__InvokebyIndex xpcom/reflect/xptcall/src/md/win32/xptcinvoke_asm_x86_64.asm:129 4 xul.dll XPCWrappedNative::CallMethod js/xpconnect/src/XPCWrappedNative.cpp:2389 5 xul.dll JS_DefinePropertyById js/src/jsapi.cpp:3733 6 xul.dll XPCNativeMember::NewFunctionObject js/xpconnect/src/XPCWrappedNativeInfo.cpp:75 7 xul.dll DEBUG_CheckWrapperThreadSafety js/xpconnect/src/XPCWrappedNative.cpp:3735 8 xul.dll XPCCallContext::XPCCallContext js/xpconnect/src/XPCCallContext.cpp:67 9 xul.dll xul.dll@0x37635f 10 xul.dll nsGenericElement::SetAttr content/base/src/nsGenericElement.cpp:5238 11 xul.dll XPC_WN_NoHelper_Resolve js/xpconnect/src/XPCWrappedNativeJSOps.cpp:734 12 xul.dll XPCWrappedNative::GetWrappedNativeOfJSObject js/xpconnect/src/XPCWrappedNative.cpp:1794 13 xul.dll XPCCallContext::Init js/xpconnect/src/XPCCallContext.cpp:190 14 xul.dll XPCCallContext::XPCCallContext js/xpconnect/src/XPCCallContext.cpp:67 15 xul.dll XPCNativeMember::GetCallInfo js/xpconnect/src/XPCWrappedNativeInfo.cpp:59 16 xul.dll XPC_WN_CallMethod js/xpconnect/src/XPCWrappedNativeJSOps.cpp:1541 More reports at: https://crash-stats.mozilla.com/report/list?signature=nsAutoCompleteController%3A%3AProcessResult%28int%2C+nsIAutoCompleteResult*%29

may be related to bug 720589, or at least, looks like crashing about there.

based on the stacks, this should have been fixed by bug 720589