AP_Scripting: Only allow scripting restart if disarmed

[IamPete1]

This requires the vehicle to be disarmed for scripting to be re-started. Scripts can still be stopped while armed. This is because I found another case where scripting restart causes a flight controller lockup and watchdog on real hardware.

In that case I restarted the math.lua test. There have been several of these that we have now fixed, but there might be more we have not found.

Crash dump output and watchdog decode from that one are here:
https://discord.com/channels/674039678562861068/719466647710072832/1120113508877598780

[timtuxworth]

Scripting is being used and recommended for hard-core flight time work like device drivers. If it can stop and stay stopped, then those recommended uses might need to be re-considered.

[IamPete1]

Scripting is being used and recommended for hard-core flight time work like device drivers. If it can stop and stay stopped, then those recommended uses might need to be re-considered.

Its not a script problem, its that restarting scripts can cause the flight controller to lock up. Its fine for the majority but there are some cases we have not tracked down.

If you don't try and restart there is no problem.

[tridge]

we need to get to the bottom of the actual cause

[IamPete1]

This is the reproduction:

• Default params, SCR_ENABLE 1, SCR_VM_I_COUNT to 100000 (10x the default)
• Load math.lua
• Reboot and let it run, you should see Math tests passed messages
• Restart scripting

I used a CubeOrange-Plus on master. The same thing works on stable, I have not tried other boards.

edit:

I have found a minimum script, just need this one line math.random(1, 0)

[tridge]

@IamPete1 this PR fixes the issue for me:
#24218

[IamPete1]

We have fixed the particular crash that prompted me to open this, #24231

However, I suspect there are others we have not found yet....