This memory leak seems to be caused by the TMemStackAllocator of FRayTracingMeshCommandOneFrameArray.


Using the FDefaultAllocator for FRayTracingMeshCommandOneFrameArray works as a workaround. 

//typedef TArray<FVisibleRayTracingMeshCommand, SceneRenderingAllocator> FRayTracingMeshCommandOneFrameArray;
typedef TArray<FVisibleRayTracingMeshCommand, FDefaultAllocator> FRayTracingMeshCommandOneFrameArray;

Steps to Reproduce

1. Open attached project [Link Removed]on ue4.26 (RayTracing is enabled for this project)
2. Start PIE
3. Enter 'stat memory'
4. Observe 'PageAllocator Used' value in stats.


'PageAllocator Used' keeps increasing.



If this repro project runs on the DebugEditor engine, it will report some assertions about MemStack.


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ComponentUE - Rendering
Affects Versions4.26
Target Fix5.0
Fix Commit17056918
CreatedJul 19, 2021
ResolvedAug 4, 2021
UpdatedNov 30, 2021