Description

This is a slightly trending crash after the 4.17.2 hotfix, although it has occurred since 4.17.0. Users have not provided any description of their actions when the crash occurred.

The callstack is very similar to UE-49773, except for the FScriptArray::ResizeTo function. And the source context is different.

Source Context

 75       void* FMallocTBB::Realloc( void* Ptr, SIZE_T NewSize, uint32 Alignment )
   76       {
   77       	IncrementTotalReallocCalls();
   78       
   79       	MEM_TIME(MemTime -= FPlatformTime::Seconds())
   80       #if UE_BUILD_DEBUG || UE_BUILD_DEVELOPMENT
   81       	SIZE_T OldSize = 0;
   82       	if (Ptr)
   83       	{
   84 ***** 		OldSize = scalable_msize(Ptr);
   85       		if (NewSize < OldSize)
   86       		{
   87       			FMemory::Memset((uint8*)Ptr + NewSize, DEBUG_FILL_FREED, OldSize - NewSize); 
   88       		}
   89       	}
Steps to Reproduce

repro steps currently unknown

Callstack
Access violation - code c0000005 (first/second chance not available)

UE4Editor_Core!rml::internal::Block::findObjectSize()
UE4Editor_Core!FMallocTBB::Realloc() [malloctbb.cpp:85]
UE4Editor_Core!FMemory::Realloc() [fmemory.inl:48]
UE4Editor_CoreUObject!FScriptArray::ResizeTo() [scriptarray.h:200]
UE4Editor_CoreUObject!UArrayProperty::DestroyValueInternal() [propertyarray.cpp:483]
UE4Editor_CoreUObject!UObject::DestroyNonNativeProperties() [blueprintsupport.cpp:2185]
UE4Editor_CoreUObject!UObject::FinishDestroy() [obj.cpp:742]
UE4Editor_CoreUObject!UObject::ConditionalFinishDestroy() [obj.cpp:935]
UE4Editor_CoreUObject!IncrementalPurgeGarbage() [garbagecollection.cpp:977]
UE4Editor_CoreUObject!CollectGarbageInternal() [garbagecollection.cpp:1509]
UE4Editor_CoreUObject!CollectGarbage() [garbagecollection.cpp:1533]
UE4Editor_Kismet!FBlueprintCompilationManagerImpl::CompileSynchronouslyImpl() [blueprintcompilationmanager.cpp:208]
UE4Editor_UnrealEd!FKismetEditorUtilities::CompileBlueprint() [kismet2.cpp:750]
UE4Editor_Kismet!FBlueprintEditor::Compile() [blueprinteditor.cpp:3291]
UE4Editor_Kismet!FBlueprintEditor::ReparentBlueprint_NewParentChosen() [blueprinteditor.cpp:2800]
UE4Editor_Kismet!FBlueprintGlobalOptionsDetails::OnClassPicked() [blueprintdetailscustomization.cpp:5158]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintGlobalOptionsDetails,0,void __cdecl() [delegateinstancesimpl.h:434]
UE4Editor_ClassViewer!SClassViewer::OnClassViewerSelectionChanged() [sclassviewer.cpp:2434]
UE4Editor_ClassViewer!TBaseSPMethodDelegateInstance<0,SClassViewer,0,TTypeWrapper<void> __cdecl() [delegateinstancesimpl.h:327]
UE4Editor_ClassViewer!TBaseSPMethodDelegateInstance<0,SClassViewer,0,void __cdecl() [delegateinstancesimpl.h:434]
UE4Editor_ClassViewer!TBaseDelegate<void,TSharedPtr<FClassViewerNode,0>,enum ESelectInfo::Type>::ExecuteIfBound() [delegatesignatureimpl.inl:624]
UE4Editor_ClassViewer!SListView<TSharedPtr<FClassViewerNode,0> >::Private_SignalSelectionChanged() [slistview.h:725]
UE4Editor_ClassViewer!STableRow<TSharedPtr<FString,0> >::OnMouseButtonUp() [stablerow.h:474]
UE4Editor_Slate!<lambda_1002768c627006711ef2f351a87ec0e7>::operator() [slateapplication.cpp:5199]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_1002768c627006711ef2f351a87ec0e7> >() [slateapplication.cpp:232]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [slateapplication.cpp:5188]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [slateapplication.cpp:5690]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [slateapplication.cpp:5670]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [windowsapplication.cpp:1718]
UE4Editor_Core!FWindowsApplication::DeferMessage() [windowsapplication.cpp:2161]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [windowsapplication.cpp:881]
UE4Editor_Core!FWindowsApplication::AppWndProc() [windowsapplication.cpp:721]
user32!UserCallWinProcCheckWow()
user32!DispatchMessageWorker()
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [windowsplatformmisc.cpp:1009]
UE4Editor!FEngineLoop::Tick() [launchengineloop.cpp:3151]
UE4Editor!GuardedMain() [launch.cpp:166]
UE4Editor!GuardedMainWrapper() [launchwindows.cpp:134]
UE4Editor!WinMain() [launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [exe_common.inl:253]
kernel32!BaseThreadInitThunk()
ntdll!RtlUserThreadStart()

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Cannot Reproduce
ComponentGameplay - Blueprint
Affects Versions4.174.17.2
Target Fix4.18
CreatedSep 28, 2017
ResolvedJan 30, 2018
UpdatedDec 10, 2018