Ray Tracing Causes Crash On Linux

nsalberg
Tue, 21 Apr 2026 14:52:57 +0000
C++

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?

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