I apologize in advance if you have an Issue Template somewhere, I didn't see it.

The Issue:
The Fabric server will occasionally lock up when running under Linux within Pterodactyl. This seems to be most closely related to world generation. When I initially created a Pterodactyl instance for this modpack, it would lock up every time it started initial world generation. Eventually, I ran it on my Windows PC, which finished world generation without issue. I then moved the files over to the Pterodactyl instance, and it booted up fine after that.

Reproduction:
Run the modpack as provided under a Java-17 Pterodactyl instance. Chances are good the problem will present itself upon initial world generation. Should it actually get past that point, login to the server with a client, change to creative mode and start flying in any direction. It will generally lock up fairly soon while generating new chunks.

Details:
When the issue occurs, the CPU usage drops to 0% and the server no longer responds to clients or internal commands (/help etc produce no output, packet captures show packets going out client-to-server, but nothing coming back). No log entries are made to indicate the problem in any log file I can find (latest, rei, or kubejs), the server (java instance, not the physical server) literally just stops. The instance has to be SIGKILL'ed and restarted. I haven't yet had the opportunity to send a SIGQUIT to the java process when this is happening yet, but if I do, I'll add the stack traces to this thread at that time.

Comments:
This report is missing a few diagnostic steps, I am aware. I plan to continue re-visiting this issue over the next few weeks. I am hoping to get a full stack dump of the issue in progress (assuming the java process responds to a SIGQUIT). I also plan to try running the server outside of Pterodactyl after the dump is attempted/procured to see if that makes any difference. This report at the moment is more of a "has anyone seen this" as my extensive googling has produced nothing so far. Also of note is that the server in question is running 5 other Minecraft instances without issue (both Fabric, Forge and Spigot) on the same Pterodactyl installation, so I don't think it's something systemic to the server itself. Any advice or further trouble-shooting steps I should take would be greatly appreciated. Thanks!

EDIT (05-02-2023): Definitely appears to be a Pterodactyl/Docker thing. Running the server in the base OS using the same Java JRE seems to run fine. The only other difference I can think of is that the Docker image in question is based on Ubuntu 22.04 and the base server is Ubuntu 18.04. Also of note, when the problem occured, the Java process did not respond to a SIGQUIT and eventually bombed with a SIGSEGV Exit Code of 139. Anyway, if anyone has any ideas I'd love to hear them. Thanks!