Garry's Mod Server Hanging [Custom Gamemode]

Hey Everyone,

I hope someone out there will be able to give me some direction or advice on how can I can sort this issue out or to debug it.
Basically, i’ve created a gamemode from scratch and using quite a few addons such as TDM Cars, VCMod, Scriptfodder scripts…etc
Everything works ok, server launches up, players can play on it fine, but at the most random of times the server just hangs for no apparent reason.
There are no crash logs, ulx logs show nothing, our own logging system shows nothing abnormal and there are no script errors either.
Each time it hangs, we check the logs but nothing seems to be consistant into knowing what is the probable cause.

It’s driving me insane as if there was an error, it’s something I could diagnose and fix, but i’m not even getting a single hint or tip to what it could be.

Does anyone out there know why gmod servers hang?
By hang I mean: when I go into console, its letting me type commands such as “ulx who” but the server isn’t responding back. If I type “exit” nothing happens either.
I have to physically exit out then start it up again. I’m running Ubuntu 15.10.
As stated above, it happens at random times, sometimes in 4 hours, sometimes 9 hours, sometimes it can run for days.

Normally i’m fine with resolving script errors, but since there is just nothing to go off, what could be causing it to hang?
Can timers cause hanging? Could an addon be causing it? Is it MySQL?

I’ve searched through Google and Facepunch and just cant find any topics about this type of issue (loads of topics about clients hanging but not about servers…etc)
Just thought I’d turn to the Garry’s Mod community before I start from scratch again.
Is there any commands I can use to diagnose/troubleshoot the hanging issue?

Thanks for your help in advance,
Regards,
Jake