I wonder whether the "replacing c in the linux kernel" is not more wishful thinking by Rust enthusiasts. As of know it has less than 1% and less than bash.
Greg Kroah-Hartman has given a talk entitled "Untrusted data in Linux — How Rust is going to save us"[1] which I think is fairly optimistic about the idea that Rust will have an increasingly large role in the kernel. The total number of lines of code is small today but that will change.
Linux kernel project stuck at C89 and refused move to c++ or even a C standard upgrade for decades. Move to C11 (a 15 year old standard) was done just a few years ago.
The fact that rust has been even accepted into the kernel is a resounding endorsement.