Projects crash when the following Project Settings are set:
• Vulkan is enabled
• Vulkan is the Default RHI
• Forward Shading is enabled
• AntiAliasing Method is set to MSAA

The different engine versions had slightly different results.
It doesn't crash, but on projec reopen it crashes during or after shader compilation.

Crashed when I set AntiAliasing to MSAA. The project will not reopen.

Crashed when I actually closed the prohect. The project will not reopen.

Found in 4.24 CL#10757647
Reproduced in 4.23.1 CL#9631420, 4.25 Main CL#10868506

Steps to Reproduce

1. Create a blank project.
2. Open Project settings.
3. Go to Platform Windows-Targeted RHIs and enable Vuklan(SM5) and set Default RHI to Vulkan.
4. Restart the engine.
5. Go to Platform Engine - Rendering and enable Forward Shading and set AntiAliasing Method to MSAA.

Result: The engine crashes in slightly different ways depending on engine version (check Description).

Expected: No engine crash.



Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0x0000009c

UE4Editor_VulkanRHI!FVulkanDynamicRHI::RHICreateGraphicsPipelineState() [d:\build\++ue4\sync\engine\source\runtime\vulkanrhi\private\vulkanpipeline.cpp:1805]
UE4Editor_RHI!FCompilePipelineStateTask::DoTask() [d:\build\++ue4\sync\engine\source\runtime\rhi\private\pipelinestatecache.cpp:792]
UE4Editor_RHI!TGraphTask<FCompilePipelineStateTask>::ExecuteTask() [d:\build\++ue4\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:847]
UE4Editor_Core!FTaskThreadAnyThread::ProcessTasks() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:1029]
UE4Editor_Core!FTaskThreadAnyThread::ProcessTasksUntilQuit() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:855]
UE4Editor_Core!FTaskThreadAnyThread::Run() [d:\build\++ue4\sync\engine\source\runtime\core\private\async\taskgraph.cpp:931]
UE4Editor_Core!FRunnableThreadWin::Run() [d:\build\++ue4\sync\engine\source\runtime\core\private\windows\windowsrunnablethread.cpp:96]

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ComponentUE - Rendering
Affects Versions4.
Target Fix4.26
Fix Commit13229725
Main Commit13229725
CreatedDec 23, 2019
ResolvedMay 7, 2020
UpdatedMay 28, 2020