I seem to remember SpaceX explaining that they used linux everywhere in their company from users desktops to rocket guidance systems and this symmetry help keep all their employees co-ordinate easier. So I don't think it's an outlandish assumption that Tesla might be run a similar way and you'll find a number of linux boxes controlling the car.
Obviously that doesn't mean it's inherently secure or anything but maybe hint that it might be using some more standard security practices than a crazy custom Tesla invented magic box.
I'd be surprised. Linux is great, but it's not the best choice for something like the control system for a self-adjusting automobile suspension. Much more likely they're using VXWorks or some other embedded RTOS.
From what I can tell it's active only in that it changes ride height, not actually adjusting the suspension through a corner so the timing is not critical at all.
You don't need anything approaching realtime for controlling an air-based suspension. If we were talking about the magneto-hydraulic suspensions that adjust constantly to road conditions like potholes and corners, then I would agree 100%. But the response rate of the pneumatic system will be far slower than the computer.
Obviously that doesn't mean it's inherently secure or anything but maybe hint that it might be using some more standard security practices than a crazy custom Tesla invented magic box.