FNiagaraParameterStore::UnbindAll() may be called from both GameThread and RenderingThread.
Each may modify the same Binding array, it causes infrequent crashes.
In my environment, I was able to reproduce the crash with a fairly high probability by using the log output code described in the repro step.
Placing a CriticalSection at UnbindAll work around this issue.
FCriticalSection GNiaagraParameterStoreUnbindingCS; // workaround void FNiagaraParameterStore::UnbindAll() { FScopeLock Lock(&GNiaagraParameterStoreUnbindingCS); // workaround UnbindFromSourceStores(); for (TPair<FNiagaraParameterStore*, FNiagaraParameterStoreBinding>& Binding : Bindings) { Binding.Value.Empty(Binding.Key, this); } Bindings.Empty(); }
1. Add the logging code to the FNiagaraParameterStoreBinding
FORCEINLINE_DEBUGGABLE void FNiagaraParameterStoreBinding::Empty(FNiagaraParameterStore* DestStore, FNiagaraParameterStore* SrcStore)
{
if (DestStore)
{
//UE_LOG(LogNiagara, Log, TEXT("Remove Src Binding: Src: 0x%p - Dst: 0x%p"), SrcStore, DestStore);
UE_LOG( LogTemp, Log, TEXT("Binding:Empty %p Src: %p : %s"), DestStore, SrcStore, IsInRenderingThread()?TEXT("Render"):TEXT("Game") ); //add this
DestStore->GetSourceParameterStores().RemoveSingleSwap(SrcStore, false);
}
DestStore = nullptr;
ParameterBindings.Reset();
InterfaceBindings.Reset();
UObjectBindings.Reset();
}
2. Open attached project on 4.26 [Link Removed]
3. Start PIE
> [Inline Frame] UE4Editor-Niagara.dll!TArray<FNiagaraParameterStore *,TSizedDefaultAllocator<32>>::RangeCheck(int Index) Line 674 C++ [Inline Frame] UE4Editor-Niagara.dll!TArray<FNiagaraParameterStore *,TSizedDefaultAllocator<32>>::operator[](int) Line 718 C++ UE4Editor-Niagara.dll!FNiagaraParameterStore::UnbindFromSourceStores() Line 463 C++ UE4Editor-Niagara.dll!FNiagaraParameterStore::UnbindAll() Line 359 C++ UE4Editor-Niagara.dll!FNiagaraParameterStore::~FNiagaraParameterStore() Line 196 C++ UE4Editor-Niagara.dll!FNiagaraEmitterInstance::~FNiagaraEmitterInstance() Line 182 C++ [Inline Frame] UE4Editor-Niagara.dll!SharedPointerInternals::FReferenceControllerOps<1>::ReleaseSharedReference(SharedPointerInternals::FReferenceControllerBase * ReferenceController) Line 282 C++ [Inline Frame] UE4Editor-Niagara.dll!SharedPointerInternals::FSharedReferencer<1>::{dtor}() Line 469 C++ [Inline Frame] UE4Editor-Niagara.dll!DestructItems(TSharedRef<FNiagaraEmitterInstance,1> * Element, int Count) Line 158 C++ UE4Editor-Niagara.dll!TArray<TSharedRef<FNiagaraEmitterInstance,1>,TSizedDefaultAllocator<32>>::Empty(int Slack) Line 1723 C++ UE4Editor-Niagara.dll!FNiagaraSystemInstance::Cleanup() Line 1168 C++ UE4Editor-Niagara.dll!FNiagaraSystemInstance::~FNiagaraSystemInstance() Line 1140 C++ UE4Editor-Niagara.dll!FNiagaraSystemInstance::`vector deleting destructor'(unsigned int) C++ [Inline Frame] UE4Editor-Niagara.dll!TDefaultDelete<FNiagaraSystemInstance>::operator()(FNiagaraSystemInstance * Ptr) Line 64 C++ [Inline Frame] UE4Editor-Niagara.dll!TUniquePtr<FNiagaraSystemInstance,TDefaultDelete<FNiagaraSystemInstance>>::{dtor}() Line 266 C++ [Inline Frame] UE4Editor-Niagara.dll!DestructItems(TUniquePtr<FNiagaraSystemInstance,TDefaultDelete<FNiagaraSystemInstance>> * Element, int Count) Line 158 C++ UE4Editor-Niagara.dll!TArray<TUniquePtr<FNiagaraSystemInstance,TDefaultDelete<FNiagaraSystemInstance>>,TSizedDefaultAllocator<32>>::Empty(int Slack) Line 1723 C++ [Inline Frame] UE4Editor-Niagara.dll!FNiagaraWorldManager::OnBatcherDestroyed_Internal(NiagaraEmitterInstanceBatcher *) Line 391 C++ UE4Editor-Niagara.dll!FNiagaraWorldManager::OnBatcherDestroyed(NiagaraEmitterInstanceBatcher * InBatcher) Line 505 C++ UE4Editor-Niagara.dll!NiagaraEmitterInstanceBatcher::OnDestroy() Line 1531 C++ UE4Editor-Engine.dll!FFXSystemSet::OnDestroy() Line 206 C++ UE4Editor-Engine.dll!FFXSystemInterface::Destroy(FFXSystemInterface * FXSystem) Line 69 C++ UE4Editor-Engine.dll!UWorld::CleanupWorldInternal(bool bSessionEnded, bool bCleanupResources, UWorld * NewWorld) Line 4541 C++ UE4Editor-Engine.dll!UEngine::LoadMap(FWorldContext & WorldContext, FURL URL, UPendingNetGame * Pending, FString & Error) Line 12764 C++ UE4Editor-Engine.dll!UEngine::Browse(FWorldContext & WorldContext, FURL URL, FString & Error) Line 12338 C++ UE4Editor-Engine.dll!UEngine::TickWorldTravel(FWorldContext & Context, float DeltaSeconds) Line 12536 C++ UE4Editor-UnrealEd.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1692 C++ UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 426 C++ UE4Editor.exe!FEngineLoop::Tick() Line 4836 C++ [Inline Frame] UE4Editor.exe!EngineTick() Line 62 C++ UE4Editor.exe!GuardedMain(const wchar_t * CmdLine) Line 169 C++ UE4Editor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 257 C++
!TArray<TTuple<FNiagaraParameterStore * __ptr64,FNiagaraParameterStoreBinding>,TSizedDefaultAllocator<32> >::RemoveAtSwapImpl() !FNiagaraParameterStore::UnbindFromSourceStores() !FNiagaraParameterStore::UnbindAll() !FNiagaraParameterStore::~FNiagaraParameterStore() !FNiagaraEmitterInstance::~FNiagaraEmitterInstance() !TArray<TSharedRef<FNiagaraEmitterInstance,1>,TSizedDefaultAllocator<32> >::Empty() !FNiagaraSystemInstance::Cleanup() !FNiagaraSystemInstance::~FNiagaraSystemInstance() !FNiagaraSystemInstance::`vector deleting destructor'() !FNiagaraWorldManager::OnWorldCleanup() !FNiagaraWorldManager::OnWorldCleanup() !TBaseStaticDelegateInstance<void __cdecl(UWorld * __ptr64,bool,bool),FDefaultDelegateUserPolicy>::ExecuteIfSafe() !TMulticastDelegate<void __cdecl(UWorld * __ptr64,bool,bool),FDefaultDelegateUserPolicy>::Broadcast() !UWorld::CleanupWorldInternal() !FSeamlessTravelHandler::Tick() !UEngine::TickWorldTravel() !UGameEngine::Tick() !FEngineLoop::Tick() !GuardedMain() !GuardedMainWrapper() !WinMain() !__scrt_common_main_seh() [d:\agent\_work\2\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288] kernel32 ntdll
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-140253 in the post.