While Linux 7.0 is the next kernel version solely over Linus Torvalds’ numbering preference, there is a notable symbolic change that was sent in overnight for this new kernel merge window: formally concluding the “Rust experiment” with upstream kernel developers now in acceptance that Rust for the Linux kernel is here to stay.
The patch was talked about back in December that the Rust experiment is over and it’s here to stay. There are already uses for Rust in production environments, some Linux distributions shipping with Rust kernel code, and millions of Android devices also using it.
Lua doesn’t have capabilities for direct access to the memory and such, and those would need to be added by either embedding Lua in C or modifying the interpreter, which is, of course, written in C. So it’s indeed mostly for scripting. Although there’s a game engine/framework Löve, where the entire game can be written in Lua.