They crash all the time. They’re absolutely awful quality. they are made almost exclusively with cheap foreign engineering. It’s really the wild west when it comes to things.
The vehicle interfaces are usually subsystem modules in the radio. Your Linux side talks to your “vehicle side” over usb, uart, SPI, etc. There is still a good module there most of the time, but it has 100% trust of its main processor.
Since 2018, US vehicles since almost all come with a firewall to separate the radio/telemetric/infotainment busses from the vehicle busses.
Their solution wasn’t to harden the fancy systems, it was just to separate them from the important ones. So the vulnerabilities are still there, just moved a little.
I despise these big stupid complicated displays that encourage accidents.
A catastrophic failure of the head unit can impact the electrical system which can do weird things with the spark plugs or other systems.
Well, to be fair, the cause and effect in this case shouldn't even be connected in a way that allows for this. It's like a bad CD in your car stereo causing your engine to fail. A smart car manufacturer makes it so that the data bus cannot send information from the public areas to the engine area. A bad car manufacturer does not put up those blocks.