Ray Tracing Causes Crash On Linux

[nsalberg]

I’m creating multiple CineCamera’s each with a CineCameraSceneCaptureComponent attached and all are rendering to a render target. After moving the camera’s around eventually the VulkanRHI will segfault.

I’m on Ubuntu 22.04.5 LTS (Jammy Jellyfish) with Unreal Engine 6.1. I was able to replicate the issue on multiple devices:
NVIDIA-SMI 580.126.09 Driver Version: 580.126.09 CUDA Version: 13.0 NVIDIA GeForce RTX 5080
and
NVIDIA-SMI 580.105.08 Driver Version: 580.105.08 CUDA Version: 13.0NVIDIA GeForce RTX 3070

[2026.04.17-13.48.03:186][ 79]LogCore: === Critical error: ===
Unhandled Exception: SIGSEGV: invalid attempt to read memory at address 0x0000000000000034

[2026.04.17-13.48.03:186][ 79]LogCore: Fatal error!

Assertion failed: IsCompleted() [File:Runtime/Core/Public/Tasks/TaskPrivate.h] [Line: 195]

libUnrealEditor-Core.so!FDebug::CheckVerifyFailedImpl2(char const*, char const*, int, char16_t const*, …) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/Misc/AssertionMacros.cpp:724]
libUnrealEditor-Core.so!UE::Tasks::Private::FTaskBase::~FTaskBase() [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Tasks/TaskPrivate.h:195]
libUnrealEditor-Core.so!FGraphEventImpl::~FGraphEventImpl() [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Async/TaskGraphInterfaces.h:720]
libUnrealEditor-VulkanRHI.so!FVulkanGPUFence::Clear() [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Tasks/TaskPrivate.h:142]
libUnrealEditor-RHI.so!FRHIGPUBufferReadback::EnqueueCopy(FRHICommandList&, FRHIBuffer*, unsigned int) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/RHI/Private/RHIGPUReadback.cpp:40]
libUnrealEditor-Renderer.so!TRDGLambdaPass<FReadbackBufferParameters, FRayTracingScene::FinishStats(FRDGBuilder&, ERDGPassFlags)::$_0>::Execute(FRHIComputeCommandList&) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Renderer/Private/RayTracing/RayTracingScene.cpp:680]
libUnrealEditor-RenderCore.so!UE::Tasks::Private::TExecutableTaskBase<FRDGBuilder::SetupParallelExecute(TStaticArray<void*, 1u, 8u> const&)::$_1, void, void>::ExecuteTask() [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/RenderCore/Private/RenderGraphBuilder.cpp:3459]
libUnrealEditor-RenderCore.so!UE::Tasks::Private::FTaskBase::TryExecuteTask() [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Tasks/TaskPrivate.h:527]
libUnrealEditor-RenderCore.so!LowLevelTasks::TTaskDelegate<LowLevelTasks::FTask* (bool), 48u>::TTaskDelegateImpl<void LowLevelTasks::FTask::Init<UE::Tasks::Private::FTaskBase::Init(char16_t const*, LowLevelTasks::ETaskPriority, UE::Tasks::EExtendedTaskPriority, UE::Tasks::ETaskFlags)::‘lambda’()>(char16_t const*, LowLevelTasks::ETaskPriority, UE::Tasks::Private::FTaskBase::Init(char16_t const*, LowLevelTasks::ETaskPriority, UE::Tasks::EExtendedTaskPriority, UE::Tasks::ETaskFlags)::‘lambda’()&&, LowLevelTasks::ETaskFlags)::‘lambda’(bool), false>::CallAndMove(LowLevelTasks::TTaskDelegate<LowLevelTasks::FTask* (bool), 48u>&, void*, unsigned int, bool) [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Tasks/TaskPrivate.h:184]
libUnrealEditor-Core.so!LowLevelTasks::FTask::ExecuteTask() [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Async/Fundamental/TaskDelegate.h:309]
libUnrealEditor-Core.so!LowLevelTasks::FScheduler::ExecuteTask(LowLevelTasks::FTask*) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/Async/Fundamental/Scheduler.cpp:365]
libUnrealEditor-Core.so!LowLevelTasks::FScheduler::WorkerLoop(LowLevelTasks::Private::FWaitEvent*, LowLevelTasks::Private::TLocalQueueRegistry<1024u, 1024u>::TLocalQueue*, unsigned int, bool) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/Async/Fundamental/Scheduler.cpp:665]
libUnrealEditor-Core.so!LowLevelTasks::FScheduler::WorkerMain(LowLevelTasks::Private::FWaitEvent*, LowLevelTasks::Private::TLocalQueueRegistry<1024u, 1024u>::TLocalQueue*, unsigned int, bool) [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/Async/Fundamental/Scheduler.cpp:783]
libUnrealEditor-Core.so!FThreadImpl::Run() [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Public/Templates/Function.h:471]
libUnrealEditor-Core.so!FRunnableThreadPThread::Run() [/mnt/horde/++UE5/Sync/Engine/Source/./Runtime/Core/Private/HAL/PThreadRunnableThread.cpp:25]
libUnrealEditor-Core.so!FRunnableThreadPThread::_ThreadProc(void*) [/mnt/horde/++UE5/Sync/Engine/Source/Runtime/Core/Private/HAL/PThreadRunnableThread.h:187]
libc.so.6!UnknownFunction(0x94ac2)
libc.so.6!UnknownFunction(0x1268bf)

[2026.04.17-13.48.03:197][ 79]LogExit: Executing StaticShutdownAfterError
Engine crash handling finished; re-raising signal 11 for the default handler. Good bye.

Anyone know a fix?

[BRGEzedeRocco]

Hello @nsalberg ,
You could try disabling Ray Tracing from the console with the following command:

r.RayTracing 0

If that does not solve the issue, I would also recommend checking the CineCameraSceneCaptureComponent. In the Details panel, under Scene Capture:

• Disable Capture Every Frame
• Under Show Flags, then Lighting Components, disable Dynamic Shadows

After that, instead of capturing automatically every frame, you could create a Set Timer by Event (I’m also leaving below how many seconds equal certain FPS values, in case it helps you test which interval works best) and handle the captures manually. This helps prevent all cameras from rendering at the same time, which may reduce the load and possible crashes.

I also found this post discussing crashes related to VulkanRHI, and it includes some possible solutions that might help you as well.

500×500 2.84 KB

Hi guys! Having some trouble here with getting Unreal Engin 5.1 working on Arch Linux. 5.0.3 still works. When I try to launch it crashes with: Fatal error: [File:./Runtime/VulkanRHI/Private/VulkanUtil.cpp I keep getting errors related to VulkanRHI.so. I have attached the full crash log. Has anyone else seen this before? My specs: Laptop: HP - 17.3" Laptop - Intel Core i5 - 8GB Memory - 256GB SSD Model: 668S3UA#ABA CPU: 11th gen Intel Core i5-1135g7 @ 2.4ghz GPU: Mesa Intel Xe RAM: 32g…

Hope it helps!