Update: It looks like Rust won’t make it for 6.0. Hopefully we’ll still see it fairly soon!
2nd Update: Initial Rust support is now targeted for 6.1. The first merge into the mainline code was completed on October 3rd.
Back in July 2020, upstream Linux developers started investigating a path for adding Rust code to the Linux kernel. That discussion was expanded upon during the Linux Plumbers Conference a month later.
Miguel Ojeda, the kernel developer primarily responsible for this effort, has released multiple patch series for this support, with v8 of the initial 43.6k lines of code being added to the development branch in August 2022.
It’s looking like it might show up officially in Linux Kernel 6.0, which as of September 4th is at release candidate 4.