On Linux, UE 5.6.1 Crash within OpenXRInput on loading a simpole VR Project

Development Platform & Builds XR Development
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1

I made a simple HelloVR Project from VR Template and UE editor try to load the project, and then, on 85% progressing, Editor crash with this error log.
Assertion failed: ((Result) >= 0) [File:./../Plugins/Runtime/OpenXR/Source/OpenXRHMD/Private/OpenXRCore.cpp] [Line: 24]

libUnrealEditor-Core.so!FDebug::CheckVerifyFailedImpl2(char const*, char const*, int, char16_t const*, …) [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Core/Private/Misc/AssertionMacros.cpp:724]
libUnrealEditor-OpenXRHMD.so!FOpenXRPath::FOpenXRPath(char const*) [/usr/local/UNREAL/UE56/Engine/Source/./../Plugins/Runtime/OpenXR/Source/OpenXRHMD/Private/OpenXRCore.cpp:24]
libUnrealEditor-OpenXRInput.so!FOpenXRInputPlugin::FOpenXRInput::FOpenXRInput(IXRTrackingSystem*) [/usr/local/UNREAL/UE56/Engine/Source/./../Plugins/Runtime/OpenXR/Source/OpenXRInput/Private/OpenXRInput.cpp:302]
libUnrealEditor-OpenXRInput.so!FOpenXRInputPlugin::StartupModule() [/usr/local/UNREAL/UE56/Engine/Source/Runtime/Core/Public/Templates/SharedPointerInternals.h:414]
libUnrealEditor-Core.so!FModuleManager::LoadModuleWithFailureReason(FName, EModuleLoadResult&, ELoadModuleFlags) [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Core/Private/Modules/ModuleManager.cpp:1023]
libUnrealEditor-Projects.so!FModuleDescriptor::LoadModulesForPhase(ELoadingPhase::Type, TArray<FModuleDescriptor, TSizedDefaultAllocator<32> > const&, TMap<FName, EModuleLoadResult, FDefaultSetAllocator, TDefaultMapHashableKeyFuncs<FName, EModuleLoadResult, false> >&) [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Projects/Private/ModuleDescriptor.cpp:756]
libUnrealEditor-Projects.so!FPluginManager::TryLoadModulesForPlugin(FPlugin const&, ELoadingPhase::Type) const [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Projects/Private/PluginManager.cpp:2693]
libUnrealEditor-Projects.so!FPluginManager::LoadModulesForEnabledPlugins(ELoadingPhase::Type) [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Projects/Private/PluginManager.cpp:2832]
UnrealEditor!FEngineLoop::Init() [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Launch/Private/LaunchEngineLoop.cpp:4603]
libUnrealEditor-UnrealEd.so!EditorInit(IEngineLoop&) [/usr/local/UNREAL/UE56/Engine/Source/./Editor/UnrealEd/Private/UnrealEdGlobals.cpp:167]
UnrealEditor!GuardedMain(char16_t const*) [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Launch/Private/Launch.cpp:164]
libUnrealEditor-UnixCommonStartup.so!CommonUnixMain(int, char**, int ()(char16_t const), void (*)()) [/usr/local/UNREAL/UE56/Engine/Source/./Runtime/Unix/UnixCommonStartup/Private/UnixCommonStartup.cpp:323]
libc.so.6!UnknownFunction(0x3574)
libc.so.6!__libc_start_main(+0x87)
UnrealEditor!_start [/usr/local/UNREAL/UE56/Engine/Binaries/Linux/UnrealEditor:-1]

I’m using UE 5.6.1 on Wayland under Fedora 42.

2

I have quest2 connected to My fedora 42 machine via usb. I know Meta quest don’t support Linux. I just want to create a VR Project based on OpenXR without any matter Quest.Is there any way to resolve or get workaround this error?
HelloVR.uproject 's content is

{
“FileVersion”: 3,
“EngineAssociation”: “A11F39FD-AADD-4954-9D31-C37FDE6CAFED”,
“Category”: “”,
“Description”: “”,
“Plugins”: [
{
“Name”: “OpenXR”,
“Enabled”: true,
“SupportedTargetPlatforms”: [
“Win64”,
“Linux”,
“Android”,
“VisionOS”
]
},
{
“Name”: “OpenXREyeTracker”,
“Enabled”: true,
“SupportedTargetPlatforms”: [
“Win64”,
“Linux”,
“Android”
]
},
{
“Name”: “OpenXRHandTracking”,
“Enabled”: true,
“SupportedTargetPlatforms”: [
“Win64”,
“Linux”,
“Android”,
“VisionOS”
]
}
],
“TargetPlatforms”: [
“Android”,
“IOS”,
“Linux”,
“Mac”,
“PS4”,
“PS5”,
“Windows”,
“WindowsNoEditor”,
“Switch”,
“XboxOne”,
“XSX”,
“VisionOS”
]
}

3

UE Editor did open the VR Project successfully while running SteamVR.
At that time, SteamVR detected definitely my quest2. I set SteamVR as OpenXR runtime.

4

If you just want to start the editor without any headset connected, try setting bStartInVR=False in the project DefaultGame.ini file.

The crash is an assertion on calling xrStringToPath for /user/hand/left which shouldn’t normally be able to fail if the OpenXR runtime is working correctly. What runtime did you have set when the crash occurred?

5

Thanks a lot.

6

What runtime did you have set when the crash occurred?

I didn’t have any runtime, also I didn’t run SteamVR at that point.

7

I’m surprised it managed to get so far without a runtime.

Unreal (and all other engines really) seems to have poor handling of OpenXR system configuration issues in general. There doesn’t seem to be good paths to getting informative error messages to either devs or end users. Especially about which runtimes are installed and being used, what API layers are active or overridden, and handling of errors from things like the headset not being connected to the runtime.

8

I absolutely agree to you. I hope they’ll improve much his artifacts on these fusion tech fields.