Rust in the 6.2 kernel

> In C it's all the same thing, of course.

Not quite; without a capacity value from a standard NUL terminated string, one can't do some useful patterns like having a single allocated "buffer" used in a loop without allocating/freeing. The equivalent of Rust's String is really things like https://developer-old.gnome.org/glib/stable/glib-Strings.html
(I'd assume there's some variant of this in the linux kernel? But not seeing it offhand)