Rust-for-Linux VS wg-allocators

Rust is backwards compatible when you stick to stable features, but the kernel uses unstable features that can and do incur breaking changes.

https://github.com/Rust-for-Linux/linux/issues/2

> How would this work?

Don't know exactly what you're asking.

> And why would it be a better idea?

Poorly written device drivers are a significant attack vector. It's one of the reasons Linux is now exploring using Rust for its own device drivers.[0] You may be asking -- why Rust and not some other language? Rust has many of the performance and interoperability advantages of C and C++, but as noted, makes certain classes of memory safety issues impossible. Rust also has significant mindshare among systems programming communities.

[0]: https://rust-for-linux.com

Ctrl-F "rust"

https://rust-for-linux.com/ links to LWN articles at https://lwn.net/Kernel/Index/#Development_tools-Rust that suggest that only basic modules are yet possible with the rust support in Linux kernels 6.2 and 6.3.

Rust-for-linux links to the Android binder module though:

> Android Binder Driver: This project is an effort to rewrite Android's Binder kernel driver in Rust.

> Motivation: Binder is one of the most security and performance critical components of Android. Android isolates apps from each other and the system by assigning each app a unique user ID (UID). This is called "application sandboxing", and is a fundamental tenet of the Android Platform Security Model.

> The majority of inter-process communication (IPC) on Android goes through Binder. Thus, memory unsafety vulnerabilities are especially critical when they happen in the Binder driver

... "Rust in the Linux kernel" (2021) https://security.googleblog.com/2021/04/rust-in-linux-kernel... :

> [...] We also need designs that allow code in the two languages to interact with each other: we're particularly interested in safe, zero-cost abstractions that allow Rust code to use kernel functionality written in C, and how to implement functionality in idiomatic Rust that can be called seamlessly from the C portions of the kernel.

> Since Rust is a new language for the kernel, we also have the opportunity to enforce best practices in terms of documentation and uniformity. For example, we have specific machine-checked requirements around the usage of unsafe code: for every unsafe function, the developer must document the requirements that need to be satisfied by callers to ensure that its usage is safe; additionally, for every call to unsafe functions (or usage of unsafe constructs like dereferencing a raw pointer), the developer must document the justification for why it is safe to do so.

> We'll now show how such a driver would be implemented in Rust, contrasting it with a C implementation. [...]

This guide with unsafe rust that calls into the C, and then with next gen much safer rust right next to it would be a helpful resource too.

What of the post-docker container support (with userspaces also written in go) should be cloned to rust first?

Rust-for-Linux issue tracker

Yes, I definitely agree that it's a problem that pr_info implicitly wraps its arguments in unsafe {}. I wrote my own Pull Request with a trival fix.

Note that this template won't work with Linux 6.1, which has very minimal Rust support. You'll want the RustForLinux tree, or maybe Linux 6.2.

You can join Rust for Linux zulip chat by requesting invite using the link in https://github.com/Rust-for-Linux/linux 's README.

Tracking issue for Storages, and a TLDR on what it is

I must have gotten confused, since from your brief discussion with CAD97 it seemed like there was a way for the concepts to live separately and that Storage could complicate things in comparison. But if implementing Allocator in terms of Storage is basically equivalent and Storage is flexible enough that I could write one to pass memory out to unsafe code, that works just as well.

https://rust-lang.github.io/rfcs/1974-global-allocators.html was the original RFC.

My vague understanding is that there's a working group https://github.com/rust-lang/wg-allocators

The further I get from working on Rust day to day, the less I know about these things, so that's all I've got for you.

If you self-reference using pointers and guarantee the struct will never move, you don't even need unsafe. If you self-reference using offsets from the struct's base pointer, you need a splash of unsafe but your struct can be freely moved without invalidating its self-referential "pointers".

Per-struct allocators are a work in progress (see https://github.com/rust-lang/wg-allocators/issues/48).

Not sure what "non thread local addresses" means, but in my experience Rust is pretty good at sending data between threads (without moving it).

Besides that allocation is not really a problem for no_std. It's resolved by using alloc crate directly, so anything usable with custom allocators is supported. Example in dasp sources - https://github.com/RustAudio/dasp/blob/master/dasp_slice/src/boxed.rs#L14-L19 . Also worth looking at this issue to check what is usable already - https://github.com/rust-lang/wg-allocators/issues/7

But that's on track for rust as well: https://github.com/rust-lang/wg-allocators/issues/7

Here: https://github.com/rust-lang/rfcs/pull/1398. there is also a working group for this: https://github.com/rust-lang/wg-allocators.

It's unstable. wg-allocators contains discussions about design and a tracking issue for collections that need an allocator https://github.com/rust-lang/wg-allocators/issues/7