Even with protections, a crash may happen. Use a service like LinuxGSM or PteroDragon to auto-restart your server within 60 seconds. Also, backup your data/ folder daily to prevent dupe-loop persistence.
Two community standards:
More sophisticated dupes use weld constraints and spawned entities that trigger each other recursively. For example: gmod server crasher dupe
Because GMod’s constraint system recalculates relative positions every frame, a chain of 100-200 complex welds can cause exponential physics calculations. The server’s CPU spikes to 100% and never recovers. Even with protections, a crash may happen