Memory leak when machines running (Client only)

[Xefyr0]

Checked for existing issues

• I have checked for existing issues, and have found none.

Tested latest version

• I have checked that this occurs on the latest version.

GregTech CEu Version

v7.4.1

Minecraft Version

1.20.1 Forge

Recipe Viewer Installed

None

Environment

Multiplayer - Dedicated Server

Cross-Mod Interaction

No

Other Installed Mods

N/a - this bug is entirely base GT.

Expected Behavior

Expected to be able to run large quantities of machines for extended periods without crashing.

Actual Behavior

After leaving several (24) LV singleblocks running while supplied by creative sources, the game crashed with an OutOfMemoryError.

Steps to Reproduce

1. This issue only manifests on a client connected to a dedicated server. After installing Forge 47.4.12 and GregTech 7.4.1 on your server and client, add -XX:MaxDirectMemorySize=128m to your Java args. This is technically optional, but drastically reduces the maximum allocation to the type of memory that's leaking which allows you to get positive results (crashes) faster.
2. Create a new world or load into an existing one.
3. Build a large array of machines that will be operating constantly, supplied with Creative Energy, Creative Tanks, and Creative Chests. I recommend covering it with a roof or disabling doWeatherCycle so that the machines don't explode in the rain and halt your progress. I used four lines of 6 machines each constantly producing and voiding Silicon from Cobblestone for 24 machines in total, but it may be helpful to build more so the effect is more pronounced - the rate of memory leakage is related to machine activity.

4. AFK. The machines will continue to produce while you are away, slowly leaking memory into the Direct Buffers. When the space runs out you will crash, producing a message akin to the screenshot in the "Actual Behavior" section. It should take you a few hours with my setup which is why I recommend you build more machines.

Optional: Install Embeddium and Oculus to get an extra entry in the F3 menu that displays the size of your Direct Buffers. This allows you to track the effect and severity of the leak more precisely while in-game.

Additional Information

This issue has been corroborated by several reports from players in the Monifactory Discord, but I have personally confirmed that the leak is present when no other mods or scripts are involved using the methods described in this report.

[Xefyr0]

Update: confirmed that the issue is reproducible on GregTech: Modern version 1.6.4 under similar conditions.

[Xefyr0]

Heapdump with GTm and Spark as the only mods:
https://drive.google.com/file/d/1iRGQs5J0Bla4-lPSX-etzGEFmT1YZNWX/view?usp=sharing

[barkerh4200-spec]

bump, any ideas what is causing this so the community can attempt to write a hotpatch

[randomusert]

does it do it only on a dedicated server or does it do it in also singleplayer?

[barkerh4200-spec]

does adding

-Dio.netty.allocator.type=unpooled

to the clients Additional Args help at all? I vibe coded a hotpatch for our specific hotfix (SOG / Sky of grind) but it depends on the following jars because it fixes other mods at the same time, but i am thinking of splitting it up or writing a gregtech only version when i get more credits, i am uploading the source to: https://github.com/barkerh4200-spec/directmemfix

libs/ — required JARs

Filename (exact)	Where to get it
forge-1.20.1-47.4.3-universal.jar	https://files.minecraftforge.net
ldlib-forge-1.20.1-1.0.49.jar	Modrinth / CurseForge — LDLib 1.0.49
gtceu-1.20.1-7.5.2.jar	Modrinth / CurseForge — GregTech Modern 7.5.2
embeddium-0.3.31+mc1.20.1.jar	Modrinth / CurseForge — Embeddium 0.3.31
SkyblockBuilder-1.20.1-5.1.28.jar	Modrinth / CurseForge — SkyblockBuilder 5.1.28

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