PCG GC Crash with Runtime Generated Content in Editor

Development Pipeline & Plugins
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1

Hi,

we’ve been experiencing a crash using PCG that generates instanced static meshes inside a closed loop spline. The PCG is set to generate at runtime with the PCG WorldActor configured to set editor cameras as sources. See Repro Project.

Crash happens when a PCG Actor gets deleted, either manually or due to replacement when dragging in a new actor. During deletion the GC gets triggered where the issue appears.

Unfortunately the crash is inconsistent and I’ve not been able to find a way to make it appear reliably.

I was unable to reproduce it in a quick test with 5.6. We won’t be able to upgrade until some time next year so I hope there is some changelist we can integrate or some other fix we can implement.

Regards,

Max

2

Steps to Reproduce

  1. Load up TestMap
  2. Drag center spline point of placed Test Actor around
  3. Drag in new Test Actor into the map
  4. Delete new Test Actor
  5. Repeat 2-4 until crash
3

Hi Max,

Thanks for reaching out.

I’ll forward this to someone in the team so they can have a look.

Cheers,

Julien

4

Hi Max,

I’ve looked into the mini-dump…it is unclear what is happening here but it does indeed seem related to PCG (crashes when calling UPCGManagedISMComponent destructor. It could be related to bad reuse of PCG Managed resources and if it doesn’t happen in 5.6 could already have been fixed (but that crash doesn’t ring a bell). Do you happen to have a small 5.4.4 project that has a good enough repro rate for us to look into? (only seeing the minidump zip here)

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Cheers,

Patrick

5

Oh I thought I did attach the Repro Project odd. Attached it again.

6

Hey Max, thanks for the repro, I managed to crash and will report back with my findings.

7

Ok I think I’ve narrowed down the fix CL to 40938728. If you are able to integrate the change it should be fairly easy.