In 2022 we will very likely see the experimental Rust programming language support within the Linux kernel mainlined. Sent out this morning were the updated patches introducing the initial support and infrastructure around handling of Rust within the kernel.
A few minutes ago Miguel Ojeda sent out the "v2" patches for Rust support in the kernel. With these updated packages, the Rust code is now relying on stable Rust releases rather than the beta compiler state previously, new modularization options added, stricter code enforcements, extra Rust compiler diagnostics enabled, new abstractions for in-kernel use, and other low-level code improvements.