2d ago

The (successful) end of the kernel Rust experiment

The topic of the Rust experiment was just discussed at the annual Maintainers Summit. The consensus among the assembled developers is that Rust in the kernel is no longer experimental — it is now a core part of the kernel and is here to stay. So the "experimental" tag will be coming off. Congratulations are in order for all of the Rust for Linux team.

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This title really bait me.
- Yeah, thought that was going the other way for a second.
  
  ditto and it made me sad; i was afraid that the maintainers had become too ossified to embrace change.
Ambiguous title is ambiguous ಠ_ಠ
- Yeah ambiguity is for C code /s
- Yep. Came here ready to rant
- My heart stopped. Sheesh.
Phoronix commentors will be furious.
You scared me for a second
This means that drivers written in Rust will have just a good a chance to be accepted as drivers written in C?
- I guess that still depends on the maintainer which is responsible. But since drivers often deal with untrusted data, which can lead to security exploits, this makes a lot of sense.
  
  If i remeber correctly, the current approach is each device/vendor family is free to choose how they want to move. for example, gpu folks are actually interested to do rust stuff (for example novo, tyr by redhat,collabora). there may be some families who do not want to move fast.
I would have guessed that mixing different programming languages would cause problems. But apparently it's working well.
It's been 20 years since I did any serious programming, so I'm a bit rusty, is that what Rust is for?
- Lots of "modern" languages don't interop terribly well with other languages, because they need a runtime environment to be executed.
  So, if you want to call a Python function from Java, you need to start a Python runtime and somehow pass the arguments and the result back and forth (e.g. via CLI or network communication).
  C, C++, Rust and a few other languages don't need a runtime environment, because they get compiled down to machine code directly.
  As such, you can call functions written in them directly, from virtually any programming language. You just need to agree how the data is laid out in memory. Well, and the general agreement for that memory layout is the C ABI. Basically, C has stayed the same for long enough that everyone just uses its native memory layout for interoperability.
  And yeah, the Rust designers weren't dumb, so they made sure that Rust can also use this C ABI pretty seamlessly. As such, you can call Rust-functions from C and C-functions from Rust, with just a bit of boilerplate in between.
  This has also been battle-tested quite well already, as Mozilla used this to rewrite larger chunks of Firefox, where you have C++ using its C capabilities to talk to Rust and vice versa.
- No, Rust is to make you feel like you haven't programmed seriously in 20 years when you first pick it up, even though you are actively doing it.
  Before the angry rust "mob" comes to get me: this is a joke. I tried Rust out of genuine curiosity, cobbled together a silly little thing, and quite liked it. The borrow checker made me feel like a total beginner again, in some aspects, and it was great to get that feeling again.
  Ultimately it does not fit my needs, but there are a few features I am pretty envious of. I can totally see why it's getting such a following, and I hope it keeps growing.
  
  Thanks, I might take a look at it just for fun. 😀
- What have you been doing since you stopped programming?
  Alternatively, why did you stop (seriously) programming?
  
  It was never a major part of my job description, and I lost interest doing small hobby projects.
Oh well, time to switch to TempleOS.
- Or get a catgirl ears. And safer memory.
  
  My memory is safe. Nobody ever knows what I'm going to forget..
- Pff you know how many layers of abstraction HolyC still has? Real computing enthusiasts write their OS in machine code. Not assembly, that's an abstraction too, literally tapping out high and low electrical pulses like you're in the Marconi room on the Titanic.
Isn’t one of the main concerns the licensing of Rust?
- No. The Rust code in the kernel is GPLv2 just like the rest of the kernel. The licence of the compiler has nothing to do with that, that's nonsense Rust haters make up.
  You can argue against independent projects like the Rust coreutils not using a copyleft license, but that has nothing to do with Rust or the kernel. There are independent C projects without non-copyleft licenses too.
  
  Ah thank you. You likely guessed the reason for the question.
  Many popular projects written in Rust, including the UUtils core utils rewrite, are MIT licensed as Rust is. There have been people that purposely confuse things by saying that “the Rust community” is undermining the GPL. I can see how that may lead somebody to believe that there is some kind of inherent licence problem with code written in Rust.
  Code written in Rust can of course be licensed however you want from AGPL to fully proprietary.
  I personally perceive a shift in license popularity towards more permissive licenses at least with the “younger generation”. The fact that so many Rust projects are permissively licensed is just a consequence of those kinds of licenses being more popular with the kinds of “modern” programmers that would choose Rust as a language to begin with. Those programmers would choose the same licenses even they used the GCC toolchain. But the “modern” languages they have to choose from are things like Rust, Swift, Zig, Go, or Gleam (all permissively licensed ). Python and TypeScript are also still trendy (also permissively licensed).
  Looking at that list, it is pretty silly to focus on Rust’s license. Most of the popular programming languages released over the past 20 years are permissively licensed.
- I have never heard the licensing of Rust being raised as a concern for the Linux kernel.
  As Charles Babbage would say, “I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question.”
  The distro I use builds the entire Linux kernel with Clang which uses the same license as Rust. Linux is bound by the same modified GPL license regardless of what compiler I use to build it.
  The compiler has no impact on the license applied to the code you build with that compiler. You can use closed source tools to build open source software and vice versa.
  And, of course, the Rust license is totally open source as it is offered as both MIT and Apache. Apache 2.0 even provides patent guarantees which can matter for something like a compiler.
  If you prefer to use GPL tools yourself, you may want to keep an eye on gccrs.
  https://rust-gcc.github.io/
  A legitimate concern about Rust may be that LLVM (Rust) supports a different list of hardware than GCC does. The gccrs project addresses that.
- Rust is mit/apache licensed? What concerns are there?
  
  rust the language is, but projects using it can be any other license, like GPL 2 or 3 or whatever cursed one that sudo has

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