Crash while unhiding streaming level in multiplayer

Development Programming & Scripting Blueprint
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1

I’ve already posted this issue a few months ago: we were supposing to had found a solution but the problem still here.

I was able to reproduce the crash in 4.16 and 4.17 as well:

here is test project (test project from Sean Flint)

  1. just open the project and fire play

  2. take a cup of coffee and wait a couple of minutes :slight_smile:

Blueprint will cycle showing/hiding sublevel every 2secs until engine will crash with following error:

Assertion failed: WorldSettings [File:D:\Build++UE4+Release-4.17+Compile\Sync\Engine\Source\Runtime\Engine\Private\Level.cpp] [Line: 435]

in log you will find several warnings like this:

LogNet: Warning: UActorChannel::ProcessBunch: SerializeNewActor failed to find/spawn actor. Actor: WorldSettings /Game/Developers/massi/Collections/UEDPIE_2_SubLevel.SubLevel:PersistentLevel.WorldSettings, Channel: 10
LogNet: Server connection received: ActorChannelFailure

Our project crash any time a level is reloaded with same stack trace…

Is this a bug or I’m doing something wrong?
Any suggested workarounds?

Thanks in advance

m.

2

it is seems like worldsettings is garbage collected after a minute then assert fails and game crash

EDIT: warning seems to fire if client hides level after it’s already been hided server-side

3

adding a delay before hiding levels server side seems to have solved the problem but it’s weird workaround and I’m not able to stream levels independently client side

pls help

4

adding a delay before hiding levels server side seems to have solved the problem but it’s weird workaround and I’m not able to stream levels independently client side

pls help

5

any chance to have this answered?
thanks in advance

6

Hello ,

After running the project for a couple of hours I did not hit a crash. I have a few questions for you that will help narrow down what issue it is that you are experiencing.

Quick questions:

  1. Can you reproduce this issue in a clean project?
  2. If so, could you provide a detailed list of steps/project so that we can reproduce this issue on our end?
  3. Could you provide screen shots of any settings/blueprints (if provided steps) that may be involved with this issue?
  4. Could you provide your complete callstack including machine ID/ login ID?
  5. Could you try and reproduce this issue in 4.17.2/4./18 preview 1?
7

Hi Rudy,

happy to hear from you

I can confirm that project crashes even in 4.17.2

It seems I forgot to set 2 players in multiplayer options

So:

1- open given project in editor

2- set number of player = 2

3- press play

4- wait for a couple of minute until editor crash (you will notice mentioned warnings in log immediately)

Submitted crash a couple of minutes ago with machine&login ids

MachineId>F6095D2940B05F5C05A7E6A11834BC97

LoginId>f6095d2940b05f5c05a7e6a11834bc97

8

call trace:

Assertion failed: WorldSettings [File:D:\Build++UE4+Release-4.17+Compile\Sync\Engine\Source\Runtime\Engine\Private\Level.cpp] [Line: 435]

UE4Editor_Core!FDebug::AssertFailed() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:349]
UE4Editor_Engine!ULevel::SortActorList() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\level.cpp:438]
UE4Editor_Engine!UWorld::AddToWorld() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\world.cpp:2143]
UE4Editor_Engine!UWorld::UpdateLevelStreamingInner() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\world.cpp:2780]
UE4Editor_Engine!UWorld::UpdateLevelStreaming() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\world.cpp:2846]
UE4Editor_Engine!UGameViewportClient::Draw() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\gameviewportclient.cpp:1223]
UE4Editor_Engine!FViewport::Draw() [d:\build++ue4+release-4.17+compile\sync\engine\source\runtime\engine\private\unrealclient.cpp:1198]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1853]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build++ue4+release-4.17+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:402]
UE4Editor!FEngineLoop::Tick()

9

I was able to reproduce this issue on our end. I have written up a report and I have submitted it to the developers for further consideration. I have provided a link to the public tracker. Please feel free to use the link provided for future updates.

Link: Unreal Engine Issues and Bug Tracker (UE-50443)

Make it a great day

10

Hi!

I have same issue here.
I play cinematics both client and server independently.
When “Level Visibility Track” has visible or hidden key, the warning will appear.

“Warning: UActorChannel::ProcessBunch: SerializeNewActor failed to find/spawn actor. Actor: WorldSettings /Game/Developers/massi/Collections/UEDPIE_2_SubLevel.SubLevel:PersistentLevel.WorldSettings, Channel: 10 LogNet: Server connection received: ActorChannelFailure”

And sometimes it will crash after a while.
At the same place Engine\Source\Runtime\Engine\Private\Level.cpp

11

Any suggestion on how to solve it in UE versions previous to 4.22?

12

just avoid to unload a level from server if clients are still using it

13

Is there a clean way to wait all clients have executed an event? I wouldn’t use delays…