https://github.com/tsgates/rust.ko implements a simple module in Rust. When you can expose C bindings to your functions and don't need much runtime support, there aren't really many limitations to what you can do.
Has anyone posted a flippant request on the kernel dev list to support kernel modules written in Rust?
Be sure to mention:
* how safe Rust is
* how unsafe C is
* reiterate that "this is the 21st century, people"
I would hope that nobody trolls the LKML like that. Not even Rust people think that the kernel should adopt Rust.
Which is not a very interesting or productive reasoning when discussing the actual merits and capabilities of a programming language.
I like Rust a lot actually, but kernel modules aren't a good use case for it.
Edit: the_grue actually has an interesting criticism of Rust, which is that a lot of existing systems problems-- problems that Rust would be well suited for--are already addressed with large C/C++ codebases. Since it's unlikely you're going to replace Linux, postgres, nginx, etc. it is interesting to ask what systems applications Rust can be used for now, without requiring people to rewrite their applications in Rust or allow Rust code to be mixed in with existing C/C++ code.
Nginx seems totally probable.
If we're talking about kernel modules in general, I'd have to disagree. I think it's a perfect language for kernel, as long it's all written in Rust. I only wanted to point out the practical impossibility of integration with existing infrastructure, such as Linux kernel, which is written entirely in C.
That said, the kernel has special requirements; I'd never advocate such a thing for Linux, specifically.