If I run exit or quit in the server console, the game just Segmentation Faults and the server restarts itself forcing me to kill the process if I want to shut down the server. I’m using Debian 7 32-bit.
Are you using steam workshop?
I have the same issue. Try vanilla gmod/sandbox and it shouldn’t crash on shutdown, then try addons one by one. Iirc it was wiremod causing it when I last tried this.