For anyone curious about the number of bugs introduced in each kernel release, LWN.net has a plot of Bugs fixed and introduced in each kernel release.
However, it has the obvious limitation that recent releases will appear to have fewer commits introducing bugs, simply because kernel developers haven't had as much time to find and fix the bugs introduced in those releases. So it'll be a while before we can actually see the consequences (positive or negative) of more widespread LLM usage by kernel developers