Hello. I’m trying seamless travel from a lobby to the main game in a blueprint project. I’m running UE5.4, testing in PIE, and using advanced steam session, advanced session, and steam sockets. Furthermore, I have set the console variable “net.AllowPIESeamlessTravel=1” in DefaultEngine.ini. Now, I call Server Travel in a Advanced Friends Game Instance and this works as expected when doing so with one or two players.
However, whenever attempting to do so with three or more players, my engine crashes with the following crash log.
Caught signal 11 Segmentation fault
libUnrealEditor-Engine.so!AActor::GetWorld() const [/opt/UnrealEngine-release/Engine/Source/./Runtime/Engine/Private/Actor.cpp:577]
libUnrealEditor-GameplayDebugger.so!UGameplayDebuggerLocalController::OnDebugDraw(UCanvas*, APlayerController*) [/opt/UnrealEngine-release/Engine/Source/./Runtime/GameplayDebugger/Private/GameplayDebuggerLocalController.cpp:208]
libUnrealEditor-GameplayDebugger.so!TBaseUObjectMethodDelegateInstance<false, UGameplayDebuggerLocalController, void (UCanvas*, APlayerController*), FDefaultDelegateUserPolicy>::ExecuteIfSafe(UCanvas*, APlayerController*) const [/opt/UnrealEngine-release/Engine/Source/Runtime/Core/Public/Delegates/DelegateInstancesImpl.h:665]
libUnrealEditor-Engine.so!void TMulticastDelegateBase<FDefaultDelegateUserPolicy>::Broadcast<IBaseDelegateInstance<void (UCanvas*, APlayerController*), FDefaultDelegateUserPolicy>, UCanvas*, APlayerController*>(UCanvas*, APlayerController*) const [/opt/UnrealEngine-release/Engine/Source/Runtime/Core/Public/Delegates/MulticastDelegateBase.h:254]
libUnrealEditor-Engine.so!UDebugDrawService::Draw(FEngineShowFlags, UCanvas*) [/opt/UnrealEngine-release/Engine/Source/./Runtime/Engine/Private/Debug/DebugDrawService.cpp:93]
libUnrealEditor-Engine.so!UDebugDrawService::Draw(FEngineShowFlags, FViewport*, FSceneView*, FCanvas*, UCanvas*) [/opt/UnrealEngine-release/Engine/Source/./Runtime/Engine/Private/Debug/DebugDrawService.cpp:76]
libUnrealEditor-Engine.so!UGameViewportClient::Draw(FViewport*, FCanvas*) [/opt/UnrealEngine-release/Engine/Source/./Runtime/Engine/Private/GameViewportClient.cpp:1953]
libUnrealEditor-Engine.so!FViewport::Draw(bool) [/opt/UnrealEngine-release/Engine/Source/./Runtime/Engine/Private/UnrealClient.cpp:1752]
libUnrealEditor-UnrealEd.so!UEditorEngine::Tick(float, bool) [/opt/UnrealEngine-release/Engine/Source/./Editor/UnrealEd/Private/EditorEngine.cpp:2276]
libUnrealEditor-UnrealEd.so!UUnrealEdEngine::Tick(float, bool) [/opt/UnrealEngine-release/Engine/Source/./Editor/UnrealEd/Private/UnrealEdEngine.cpp:547]
UnrealEditor!FEngineLoop::Tick() [/opt/UnrealEngine-release/Engine/Source/./Runtime/Launch/Private/LaunchEngineLoop.cpp:5915]
UnrealEditor!GuardedMain(char16_t const*) [/opt/UnrealEngine-release/Engine/Source/./Runtime/Launch/Private/Launch.cpp:182]
libUnrealEditor-UnixCommonStartup.so!CommonUnixMain(int, char**, int (*)(char16_t const*), void (*)()) [/opt/UnrealEngine-release/Engine/Source/./Runtime/Unix/UnixCommonStartup/Private/UnixCommonStartup.cpp:269]
libc.so.6!UnknownFunction(0x2a1c9)
libc.so.6!__libc_start_main(+0x8a)
UnrealEditor!_start()
Furthermore, I’ve piped the execution from command line to a log file and this is the relevant area
[2024.11.15-19.46.41:129][248]LogStats: SeamlessTravel FlushLevelStreaming - 0.000 s
[2024.11.15-19.46.41:129][248]LogWorld: Bringing World /Game/Maps/StartMenus/UEDPIE_1_Transition_Level.Transition_Level up for play (max tick rate 0) at 2024.11.15-14.46.41
[2024.11.15-19.46.41:129][248]LogWorld: Bringing up level for play took: 0.000385
[2024.11.15-19.46.41:129][248]LogWorld: Sending NotifyLoadedWorld for LP: LocalPlayer_1 PC: BP_MultiplayerLobby_PlayerController_C_0
[2024.11.15-19.46.41:129][248]LogNet: Verbose: NotifyLoadedWorld Begin
[2024.11.15-19.46.41:129][248]LogNet: VeryVerbose: GetFunctionCallspace RemoteRole Remote ServerNotifyLoadedWorld
[2024.11.15-19.46.41:129][248]LogNetTraffic: Sent RPC: BP_MultiplayerLobby_PlayerController_C /Game/Maps/StartMenus/UEDPIE_1_Transition_Level.Transition_Level:PersistentLevel.BP_MultiplayerLobby_PlayerController_C_0::ServerNotifyLoadedWorld [52.4 bytes]
[2024.11.15-19.46.41:129][248]LogNetTraffic: VeryVerbose: Sending: FOutBunch: Channel[3] ChSequence: 945 NumBits: 419 PacketId: 0 bOpen: 0 bClose: 0 bIsReplicationPaused: 0 bReliable: 1 bPartial: 0//0//0 bHasPackageMapExports: 0
[2024.11.15-19.46.41:129][248]LogNetTraffic: Verbose: FNetPacketNotify::WriteHeader - Seq 2052, AckedSeq 5751 bReFresh 0 HistorySizeInWords 1
[2024.11.15-19.46.41:129][248]LogNetTraffic: Verbose: UNetConnection::SendRawBunch. ChIndex: 3. Bits: 419. PacketId: 2052
[2024.11.15-19.46.41:129][248]LogNet: Verbose: NotifyLoadedWorld End
[2024.11.15-19.46.41:129][248]LogWorld: StartLoadingDestination to: /Game/Maps/ThirdPersonMap
CommonUnixCrashHandler: Signal=11
[2024.11.15-19.46.41:168][248]LogCore: === Critical error: ===
Unhandled Exception: SIGSEGV: invalid attempt to read memory at address 0x0000000000000008
[2024.11.15-19.46.41:168][248]LogCore: Fatal error!
Does anyone know the cause of this problem?