One Of The Rust Linux Kernel Maintainers Steps Down - Cites "Nontechnical Nonsense"

Linux@lemmy.ml – 508 points – 2 months ago

One Of The Rust Linux Kernel Maintainers Steps Down - Cites "Nontechnical Nonsense"

Wedson Almeida Filho is a Microsoft engineer who has been prolific in his contributions to the Rust for the Linux kernel code over the past several years. Wedson has worked on many Rust Linux kernel features and even did a experimental EXT2 file-system driver port to Rust. But he's had enough and is now stepping away from the Rust for Linux efforts.

From Wedon's post on the kernel mailing list:

I am retiring from the project. After almost 4 years, I find myself lacking the energy and enthusiasm I once had to respond to some of the nontechnical nonsense, so it's best to leave it up to those who still have it in them.

...

I truly believe the future of kernels is with memory-safe languages. I am no visionary but if Linux doesn't internalize this, I'm afraid some other kernel will do to it what it did to Unix.

Lastly, I'll leave a small, 3min 30s, sample for context here: https://youtu.be/WiPp9YEBV0Q?t=1529 -- and to reiterate, no one is trying force anyone else to learn Rust nor prevent refactorings of C code."

Oof, that video... I don't have enough patience to put up with that sort of thing either. I wonder how plausible a complete Rust fork of the kernel would be.

It's always been this way. Except that it was kernel developers arguing with kernel developers over C code. Now it's relative newcomers arguing with kernel developers over Rust code that the kernel devs don't necessarily care about. Of course it's going to be a mess.

A fork is of course possible, but operating systems are huge and very complex, you really don't want to alienate these folks that have been doing exclusively this for 30 years. It would be hard to keep the OS commercially viable with a smaller group and having to do both the day to day maintenance, plus the rewrite. It's already difficult as it is currently.

Rust will be a huge success in time, long after the current names have lost their impetus. This is not a "grind for 4 years and it's done" project.

folks that have been doing this exclusively for 30 years

And yet the number of people I hear “just switch to Linux!” When the other person has been using Windows for 30 years blows my mind.

Inertia is a hell of a drug.

I wouldn't tell a Windows developer with 30 years experience to just switch to developing for Linux.
Users are different. Most people who have used Windows for 30 years never touch anything outside of the desktop, taskbar and Explorer.

I have been using Windows for 30 years and Linux for 25 years (debian since 99'). I really would not bash (pun intended) windows users so much, there is place for both of them.

It’s insane to find a windows user that doesn’t live in the terminal, it’s just not designed for it

Linux has a gui for everything

That person in the audience was really grinding my gears. Just let the folks you're talking to answer you; no need to keep going on your diatribe when it's based on a false assumption and waste the whole room's time.

let's not lose focus of what's important here, and that is a room full of people hearing my voice and paying attention to me for as long as I manage to hold it

I wonder how plausible a complete Rust fork of the kernel would be.

It sounds highly impractical, and it would probably introduce more issues than Rust solves, even if there were enough people with enough free time to do it. Any change must be evolutionary if it's going to be achievable.

NOT a fork of Linux, but Redox is aiming for a Unix-like OS based on Rust – but even with “source compatibility” with Linux/BSD and drivers being in userspace, my guess would be hardware drivers are still going to be a big speed bump

All you need nowadays for a decent Unix-like is compatibility with a handful of Linux softwares and a web browser. Hell, if you could get WINE working on your kernel you could maybe support as many Windows apps/games as Linux for free.

The big issue, as I see it, is performant drivers for a wide range of hardware. That doesn't come easy, but I wonder if that can be addressed in a way I'm too inexperienced to know.

But projects like Redox are a genuine threat to the hegemony of Linux - if memory safety isn't given the true recognition it deserves, projects like Redox serve to be the same disrupting force as Linux once was for UNIX.

Redox also takes some inspiration from Plan9 and https://doc.redox-os.org/book/ch05-00-schemes-resources.html is interesting. Also reading https://drewdevault.com/2022/11/12/In-praise-of-Plan-9.html made me a bit more interested in things trying to be more Plan9-like than Unix-like.

Just fork and port Ext4 to Rust and let the little shit sit in his leaking kiddy pool out back.

There's certainly a history of Unix and Unix-like forks; which is rather simple compared to the Linux distro forks (go right to the big pic).

That's pretty well answered here: http://vger.kernel.org/lkml/#s15-3

Site is unreachable

You should do it. The Linux kernel is a C project. You can't change a 30-year project on a dime. Make your own project with Rust and hookers.

Why not React?

Ted Ts'o is a prick with a god complex. I understand his experience is hard to match, we all have something in our lives we're that good at, but that does not need to lead to acting like a fucking religious fanatic.

I understand his experience is hard to match, we all have something in our lives we're that good at

At some point, that mix of experience and ego becomes a significant liability. He's directly hurting the adoption of Rust in the kernel, while the C code he's responsible for is full of problems that would have been impossible if written in safe Rust.

CVE-2024-42304 — crash from undocumented function parameter invariants
CVE-2024-40955 — out of bounds read
CVE-2024-0775 — use-after-free
CVE-2023-2513 — use-after-free
CVE-2023-1252 — use-after-free
CVE-2022-1184 — use-after-free
CVE-2020-14314 — out of bounds read
CVE-2019-19447 — use-after-free
CVE-2018-10879 — use-after-free
CVE-2018-10878 — out of bounds write
CVE-2018-10881 — out of bounds read
CVE-2015-8324 — null pointer dereference
CVE-2014-8086 — race condition
CVE-2011-2493 — call function pointer in uninitialized struct
CVE-2009-0748 — null pointer dereference

Dude, three CVEs were enough. Stop kicking the blood puddle.

crash from undocumented function parameter invariants

My favourite, as that was the exact point the dev was making in his talk, that the stuff is badly documented and that the function signature would document it perfectly.

My favorite, as that is the exact point made by anti-rust people.

What kind of type signature would prove the first block of any directory in an ext4 filesystem image isn't a hole?

The first directory block is a hole. But type == DIRENT, so no error is reported. After that, we get a directory block without '.' and '..' but with a valid dentry. This may cause some code that relies on dot or dotdot (such as make_indexed_dir()) to crash

The problem isn't that the block is a hole. It's that the downstream function expects the directory block to contain . and .., and it gets given one without because of incorrect error handling.

You can encode the invariant of "has dot and dot dot" using a refinement type and smart constructor. The refined type would be a directory block with a guarantee it meets that invariant, and an instance of it could only be created through a function that validates the invariant. If the invariant is met, you get the refined type. If it isn't, you only get an error.

This doesn't work in C, but in languages with stricter type systems, refinement types are a huge advantage.

Wouldn't it still crash when the smart constructor was called?

If it were poorly designed and used exceptions, yes. The correct way to design smart constructors is to not actually use a constructor directly but instead use a static method that forces the caller to handle both cases (or explicitly ignore the failure case). The static method would have a return type that either indicates "success and here's the refined type" or "error and this is why."

In Rust terminology, that would be a Result.

For Go, it would be (*RefinedType, error) (where dereferencing the first value without checking it would be at your own peril).

C++ would look similar to Rust, but it doesn't come as part of the standard library last I checked.

C doesn't have the language-level features to be able to do this. You can't make a refined type that's accessible as a type while also making it impossible to construct arbitrarily.

You can do that in C, too.

You're going to need to cite that.

I'm not familiar with C23 or many of the compiler-specific extensions, but in all the previous versions I worked with, there is no type visibility other than "fully exposed" or opaque and dangerous (void*).

You could try wrapping your Foo in

typedef struct {
    Foo validated
} ValidFoo;

But nothing stops someone from being an idiot about it and constructing it by hand:

ValidFoo trustMeBro;
trustMeBro.validated = someFoo;
otherFunction(trustMeBro);

Or even just casting it.

Foo* someFoo;
otherFunction((ValidFoo*) someFoo);

Yes, this is like not checking an error code.

That's not the point, though. The point is to use a nominal type that asserts an invariant and make it impossible to create an instance of said type which violates the invariant.

Both validation functions and refinement types put the onus on the caller to ensure they're not passing invalid data around, but only refinement types can guarantee it. Humans are fallible, and it's easy to accidentally forget to put a check_if_valid() function somewhere or assume that some function earlier in the call stack did it for you.

With smart constructors and refinement types, the developer literally can't pass an unvalidated type downstream by accident.

Agreed. His experience might be useful if he were there to engage, but he’s clearly not. It seems like he just wanted to shout down the project and it seems like he was somewhat successful.

No intention of validating that behavior, it's uncalled for and childish, but I think there is another bit of "nontechnical nonsense" on the opposite side of this silly religious war: the RIIR crowd. Longstanding C projects (sometimes even projects written in dynamic languages...?) get people that know very little about the project, or at least have never contributed, asking for it to be rewritten or refactored in Rust, and that's likely just as tiring as the defensive C people when you want to include Rust in the kernel.

People need to chill out on both sides of this weird religious war. A programming language is just a tool: its merits in a given situation should be discussed logically.

I imagine this mentality is frustrating because of how many times they have to explain that they weren't forcing people to learn Rust and that the Rust bindings were second class citizens. They never said to rewrite the kernel in Rust.

That's disengenuous though.

We're not forcing you to learn rust. We'll just place code in your security critical project in a language you don't know.
Rust is a second class citizen, but we feel rust is the superior language and all code should eventually benefit from it's memory safety.
We're not suggesting that code needs to be rewritten in rust, but the Linux kernel development must internalise the need for memory safe languages.

No other language community does what the rust community does. Haskellers don't go to the Emacs project and say "We'd like to write Emacs modules, but we think Haskell is a much nicer and safer functional language than Lisp, so how about we add the capability of using Haskell and Lisp?". Pythonistas didn't add Python support to Rails along side Ruby.

Rusties seem to want to convert everyone by Trojan horsing their way into communities. It's extremely damaging, both to those communities and to rust itself.

It doesn't help that the Rust community tends to bring extremely divisive politics with it in places and ways that just don't need to happen, starting battles that aren't even tangentially related to programming.

That is the most sensible look into this so far.

Who is Ted Ts' in this context?

He's the guy you hear vexing rust in the video posted. While both languages have their pros and cons, he chooses to just blast this other guy by repeating the same crap over and over without letting him reply. Basically the kind of person with a "I win because I'm louder" demeanor.

Who the fuck is this little shit? Can't they even be a little considerate towards rust? Just because they have 15 years worth of inertia for C doesn't mean they can close their eyes and say "nope, I'm not interested". I do not see how the kernel can survive without making rust a first class citizen

It’s Ted Ts’o, the maintainer of the ext4 filesystem amongst other things.

little shit

Though you’re still accurate despite his seniority.

There's really only one valid response to Ted Ts'o:

If you think you can do better with C, prove it.

You seem really invested in pointing out those shortcomings. I respect that.

Arrogant hypocrites are a pet peeve of mine. If someone is going to act like progressive technology changes are beneath them and unnecessary, they should be able to put their money where their mouth is.

Supa Hot Fire gif with large text "put some ice on that burn" overlaid on it

Somebody needs to send a public email to the kernel mailing lists with this

How many vulnerabilities have the kernel Rust team introduced in the same time period on the same code?

Let me know when you find one?

Memory ownership isn't the only source of vulnerabilities. It's a big issue, sure, but don't think rust code is invulnerable.

Of course. Rust isn't immune to logic errors, off-by-one mistakes, and other such issues. Nor is it memory safe in unsafe blocks.

Just by virtue of how memory safety issues account for 50%+ of vulnerabilities, it's worth genuinely considering as long as the bindings don't cause maintainability issues.

The bindings cause maintainability issues. That's the problem.

The comments from that article are some of the most vitriolic I've ever seen on a technical issue. Goes to prove the maintainer's point though.

Some are good for a laugh though, like assertions that Rust in the kernel is a Microsoft sabotage op or LLVM is for grifters and thieves.

This is a little off topic and admittedly an oversimplification, but people saying Rust's memory safety isn't a big deal remind me of people saying static typing isn't a big deal.

Totally

Someone linked the thread from Phoronix forum and the comments are so awful. Imagine having to deal with people like this.

One of them reads:

We need Microsoft people like we need fleas. Why can't they work for projects we don't like, like GNOME?

It is funny because Ts'o works at Google, lol.

Phoronix comments were always dumb, like, infuriating bad, I don't even read them anymore, the moderation on that site don't give a fuck about toxicity in there

Avis/Bridei/Artem has been active as a super troll on that forum for years and absolutely nothing had been done

Beyond moderation, Phoronix is a case study in why downvotes are a good thing. Those idiots going on dumb tangents would continue, while the rest of us can read the actual worthwhile comments (which does happen, given AMD employees and the like comment there sometimes).

I've asked one question, one time in those comments and it just got buried in people spitting venom at each other about their file system preferences.

Phoronix comments are a special place on the internet. Don't go there for a good discussion.

I once started reading the comments on bcachefs. It was a extremely heated for no reason. People were screaming on the nature of btrfs

The video attached is a perfect example of the kind of "I'm not prepared to learn anything new so everyone else is wrong" attitude that is eating away at Linux like a cancer.

If memory safety isn't adopted into the kernel, and C fanaticism discarded, Linux will face the same fate as the kernels it once replaced. Does the Linux foundation want to drag its heels and stuff millions into AI ventures whilst sysadmins quietly shift to new kernels that offer memory safety, or does it want to be part of that future?

If Linux gets rewritten in Rust it will be a new kernel, not Linux. You can make new kernels, even in Rust but they aren't Linux. You can advertise them at Linux conferences but you can't force every Linux dev to work on your new Rust kernel.

There is no "your" new rust kernel. There is a gigantic ship of Theseus that is the Linux kernel, and many parts of it are being rewritten, refactored, removed an added all the time by god knows how many different people. Some of those things will be done in rust.

Can we stop reacting to this the way conservatives react to gay people? Just let some rust exist. Nobody is forcing everyone to be gay, and nobody is forcing everybody to immediately abandon C and rewrite everything in rust.

Isn't Linux still Linux even though probably a lot of the original code is gone? Why would slowly rewriting it whole, or just parts, in Rust make it stop being Linux?

Ship of Theseus

Nobody is proposing rewriting the whole kernel in Rust.

Is a single line of code in the kernel completely unchanged since its birth?

Linux is whatever the Linux Mark Institute says it is.

the crew on the Ship of Theseus would like a word with you. Because if you strip out every subsystem and replace them with a different language, everyone would still call it Linux and it would still work as Linux.

Linux isn't "a bunch of C code" it's an API, an ABI, and a bunch of drivers bundled into a monorepo.

Linux is a development ecosystem. If everyone agrees to switch to Rust it can switch to Rust with continuity. But they won't.

There's always going to be pushback on new ideas. He's basically asking people questions like "Hey how does your thing work? I want to write it in rust." and gets the answer "I'm not going to learn rust.".

I think rust is generally a good thing and with a good amount of tests to enforce behavior it's possible to a functionally equivalent copy of the current code with no memory issues in future maintenance of it. Rewriting things in rust will also force people to clarify the behavior and all possible theoretical paths a software can take.

I'm not gonna lie though, if I would have worked on software for 20 years and people would introduce component that's written in another language my first reaction would be "this feels like a bad idea and doesn't seem necessary".

I really hope that the kernel starts taking rust seriously, it's a great tool and I think it's way easier to write correct code in rust than C. C is simple but lacks the guardrails of modern languages which rust has.

The process of moving to rust is happening but it's going to take a really long time. It's a timescale current maintainers don't really need to worry about since they'll be retired anyway.

I apologize if this is more nontechnical nonsense as Im not a coder, but if the projects are open source, cant he just read and translate the code?

For the same reason spoken languages often have semantic structures that make a literal translation often cumbersome and incorrect, translating nontrivial code from one language into another without being a near expert in both langauges, as well as being an expert in the project in question, can lead to differences in behaviour varying from "it crashes and takes down the OS with it", to "it performs worse".

I'll add that even when you're an expert in both languages, it's common to see WTF's in the original and not be sure if something is a bug or just weird behavior that's now expected. Especially when going from a looser to a more strict language.

I've translated huge projects and most of the risk is in "you know the original would do the wrong thing in these x circumstances -- I'm pretty sure that's not on purpose but.... Maybe? Or maybe now someone depends on it being wrong like this?"

Even if you wrote the code yourself you can come back to it a while later and have a wtf moment ¯\_(ツ)_/¯

Also, even if you think it's a bug it might be a feature that other people use and "fixing" changing it might break systems.

From a developer standpoint you're taking someone's baby, cloning it into a language they don't understand and deprecating the original. Worse, if you're not actually interested in taking over the project you've now made it abandonware because the original developer lost heart and the person looking for commit counts on GitHub has moved on.

Obviously these extremes don't always apply, but a lot of open source relies on people taking a personal interest. If you destroy that, you might just destroy the project.

I am no visionary but if Linux doesn’t internalize this, I’m afraid some other kernel will do to it what it did to Unix.

Maybe that's not a bad thing? If you ask me the GNU people are missing a trick. Perhaps if they rewrote Hurd in Rust they could finally shed that "/Linux".

They will write kernel in Ada

GNU isn't punchy though; as soon as any punchy word get's associated with them, people will use that word instead, and we'll just get GNU/Thermite or GNU/Abson or something.

Easy, GNU->GUN

Gun! Unix? Not!

Are the version numbers going to be mm or caliber?

Gotta be mm to make sense unfortunately, Linux-GUN 7.62.11

Maybe a pipe dream, but I would love to see RedoxOS get some traction. A rust based microkernel is a promising concept.

omfg, that guy in the video...

Video url:

https://youtu.be/WiPp9YEBV0Q?t=1529

At the cost of sounding naive and stupid, wouldn't it be possible to improve compilers to not spew out unsafe executables? Maybe as a compile time option so people have time to correct the source.

the semantics of C make that virtually impossible. the compiler would have to make some semantics of the language invalid, invalidating patterns that are more than likely highly utilized in existing code, thus we have Rust, which built its semantics around those safety concepts from the beginning. there’s just no way for the compiler to know the lifetime of some variables without some semantic indication

At the cost of sounding naive and stupid

It may be a naive question, but it's a very important naive question. Naive doesn't mean bad.

The answer is that that is not possible, because the compiler is supposed to translate the very specific language of C into mostly very specific machine instructions. The programmers who wrote the code, did so because they usually expect a very specific behavior. So, that would be broken.

But also, the "unsafety" is in the behavior of the system and built into the language and the compiler.

It's a bit of a flawed comparison, but you can't build a house on a foundation of wooden poles, because of the advantages that wood offers, and then complain that they are flammable. You can build it in steel, but you have to replace all of the poles. Just the poles on the left side won't do.

And you can't automatically detect the unsafe parts and just patch those either. If we could, we could just fix them directly or we could automatically transpile them. Darpa is trying that at the moment.

Thank you and all the others that took time to educate me on what is for me a "I know some of those words" subject

Meaning a (current) kernel is actually a C to machine code transpiler?

The problem is that C is a prehistoric language and don't have any of the complex types for example. So, in a modern language you create a String. That string will have a length, and some well defined properties (like encoding and such). With C you have a char * , which is just a pointer to the memory that contains bytes, and hopefully is null terminated. The null termination is defined, but not enforced. Any encoding is whatever the developer had in mind. So the compiler just don't have the information to make any decisions. In rust you know exactly how long something lives, if something try to use it after that, the compiler can tell you. With C, all lifetimes lives in the developers head, and the compiler have no way of knowing. So, all these typing and properties of modern languages, are basically the implementation of your suggestion.

Modern C compilers have a lot of features you can use to check for example for memory errors. Rusts borrow-checker is much stricter as it's designed to be part of the language, but for low-level code like the Linux kernel you'll end up having to use Rust's unsafe feature on a lot of code to do things from talking to actual hardware to just implementing certain data structures and then Rust is about as good as C.

Compilers follow specs and in some cases you can have undefined behavior. You can and should use compiler flags but should complement that with good programming practices (e.g. TDD) and other tools in your pipeline (such as valgrind).

If you write unsafe code then how should it compile?

I’d like to add that there’s a difference between unsafe and unspecified behavior. Sometimes I’d like the compiler to produce my unsafe code that has specified behavior. In this case, I want the compiler to produce exactly that unsafe behavior that was specified according to the language semantics.

Especially when developing a kernel or in an embedded system, an example would be code that references a pointer from a hardcoded constant address. Perhaps this code then performs pointer arithmetic to access other addresses. It’s clear what the code should literally do, but it’s quite an unsafe thing to do unless you as the developer have some special knowledge that you know the address is accessible and contains data that makes sense to be processed in such a manner. This can be the case when interacting directly with registers representing some physical device or peripheral, but of course, there’s nothing in the language that would suggest doing this is safe. It’s making dangerous assumptions that are not enforced as part of the program. Those assumptions are only true in the program is running on the hardware that makes this a valid thing to do, where that magical address and offsets to that address do represent something I can read in memory.

Of course, pointer arithmetic can be quite dangerous, but I think the point still stands that behavior can be specified and unsafe in a sense.

This has been done to a limited extent. Some compilers can check for common cases and you can enforce these warnings as errors. However, this is generally not possible as others have described because the language itself has behaviors that are not safe, and too much code relies on those properties that are fundamentally unsafe.

1 more...

I admit I'm biased towards C-languages out of sheer personal preference and limited exposure to Rust but I am wondering, are there any major technical barriers to Rust replacing these languages in it's current form anymore?

I know there has been a lot of movement towards supporting Rust in the last 6 years since I've become aware of it, but I also get flashbacks from the the early 00's when I would hear about how Java was destined to replace C++, and the early 2010's when Python was destined to replace everything only to realize that the hype fundamentally misunderstood the use case limitations of the various languages.

Its mainly a matter of stabilizing existing features in the language - there are rust modules in the linux kernel as of 6.1 but they have to be compiled with the nightly compiler.

Rust is a very slow moving , get it right the first time esque, project. Important and relatively fundamental stuff is currently and has been useable and 99% unchanging for years but hasnt been included in the mainline compiler.

Also certain libraries would be fantastic to have integrated into the standard library, like tokio, anyhow, thiserror, crossbeam, rayon, and serde. If that ever happens though itll be in like a decade.

Oh and try blocks.

I see. Thanks for the explanation.

3min 30s, sample for context

If you keep watching for 10 minutes, it's an interesting discussion. Too bad they had to cut it short due to time.

Who was the guy that had a lot of pauses with mmmmmm when talking?

What is so hard to understand, C Is a fucking security issues?

You can't teach old dogs new tricks.

You actually can. And it's not that hard. I had a 14 year old German shepherd mix, who learned several new tricks before her death. I taught a partially blind 79 year old to use a computer, general internet, and email, and was communicating with her [via email] for a number of years before she lost the rest of her vision.

Old dogs, as it were, absolutely can learn new tricks.

Sorry, I just don't like this idiom, because it puts people in a box in which they do not belong.

Many years ago at work, when PCs started to spread, I taught a 60 years old lady how to use one. She never saw a PC before yet she learned pretty well, and I saw much younger people not learning.

Being willing to learn doesn't depend on age, it's a mindset, either you have it or you don't, and if you do have it, it will last your entire life.

That's very wholesome to hear! :) Thank you for sharing. I'm glad it's not the case.

My grandpa taught himself to text when he was 89. He just wrote a translation table:
A = 2
B = 22
C = 222
D = 3
...

You can, but you can't turn a 30 year project on a dime. They're understandably frustrated that newcomers keep coming and screaming RUST RUST RUST RUST RUST

yeah but this isn't newcomers making noise. This is seasoned devs making meaningful contributions, and getting reactionary responses

The kernel is mostly written in C, by C developers... understandably they're rather refactor C code to make it better instead of rewritting everything in the current fancy language that'll save the world this time (especially considering proponents of said language always, at every chance they get, sell it as C is crap, this is better).

Linux is over 30yo and keeps getting better and more stable, that's the power of open-source.

This sounds exactly like the type of nontechnical nonsense they're complaining about: attacking a strawman ("they're trying to prevent people from refactoring C code and making them rewrite everything in the current fancy language") even after explicitly calling out that that was not going to happen ("and to reiterate, no one is trying force anyone else to learn Rust nor prevent refactorings of C code").

They said it wasn't going to happen but their plan will result in it happening, how do you square that?

You tell me how it will result in it happening. Who even has the power to force people to learn Rust?

Linus and GKH, if they merge something that breaks every time C programmers change a kernel API

And where did you find that they will do that?

Most reasonable people say c is good, rust is better

Better in what ways? Rust's strong points are not to just make a program more stable, but more secure from a memory standpoint and I don't think Linux keeps improving on that

From other discussions I've seen, the guy stepping down was frustrated by having C code rejected that made lifetime guarantees more explicit. No rust involved. The patch was in service of rust bindings, but there was 0 rust code being reviewed by maintainers.

at every chance they get, sell it as C is crap, this is better

For 'sendmail' values of $C, this resembles another argument. Also, of course for $C=sysvinit.

C is crap for anything where security matters. I'll happily take that debate with anyone who thinks differently.

No idea what you’re being downvoted. Just take a look at all the critical CVSS scored vulnerabilities in the Linux kernel over the past decade. They’re all overwhelmingly due to pitfalls of the C language - they’re rarely architectural issues but instead because some extra fluff wasn’t added to double check the size of an int or a struct etc resulting in memory corruption. Use after frees, out of bounds reads, etc.

These are pretty much wiped out entirely by Rust and caught at compile time (or at runtime with a panic).

The cognitive load of writing safe C, and the volume of extra code it requires, is the problem of C.

You can write safe C, if you know what you’re doing (but as shown by the volume of vulns, even the world’s best C programmers still make slip ups).

Rust forces safe(r) code without any of the cognitive load of C and without having to go out of your way to learn it and religiously implement it.

They're being downvoted because it's a silly comment that is basically unrelated and also extremely unhelpful. Everyone can agree that C has footguns and isn't memory safe, but writing a kernel isn't memory safe. A kernel written in Rust will have tons of unsafe, just look at Redox: https://github.com/search?q=repo%3Aredox-os%2Fkernel%20unsafe&type=code That doesn't mean it isn't safer, even in kernel space, but the issues with introducing Rust into the kernel, which is already written in C and a massive project, are more nuanced than "C bad". The religious "C bad" and "C good" arguments are kinda exactly the issue on display in the OP.

I say this as someone who writes mostly Rust instead of C and is in favor of Rust in the kernel.

The difference is that now you have a scope of where the memory unsafe code might be(unsafe keyword) and you look there instead of all the C code.

I agree and think that should be helpful, but I hesitate to say how much easier that actually makes writing sound unsafe code. I'd think most experienced C developers also implicitly know when they're doing unsafe things, with or without an unsafe block in the language -- although I think the explicit unsafe should likely help code reviewers and tired developers.

It is possible to write highly unsafe code in Rust while each individual unsafe block appears sound. As a simple example: https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=6a1428d9cae5b9343b464709573648b4 [1] Run that on Debug and Release builds. Notice the output is different? Don't take that example as some sort of difficult case, you wouldn't write this code, but the concepts in it are a bit worrisome. That code is a silly example, but each individual unsafe block appears sound when trying to reason only within the block. There is unsafe behavior happening outside of the unsafe blocks (the do_some_things function should raise eyebrows), and the function we ultimately end up in has no idea something unsafe has happened.

Unsafe code in Rust is not easy, and to some extent it breaks abstractions (maybe pointers in general break abstractions to some extent?). noaliases in that playground code rightly assumes you can't have a &ref and &mut ref to the same thing, that's undefined behavior in Rust. Yet to understand the cause of that bug you have to look at all function calls on the way, just as you would have to in C, and one of the biggest issues in the code exists outside of an unsafe block.

[1]: If you don't want to click that link or it breaks, here is the code:

fn uhoh() {
    let val = 9;
    let val_ptr: *const usize = &amp;val;
    do_some_things(val_ptr);
    println!("{}", val);
}

fn do_some_things(val: *const usize) {
    let valref = unsafe { val.as_ref().unwrap() };
    let mut_ptr: *mut usize = val as *mut usize;
    do_some_other_things(mut_ptr, valref);
}

fn do_some_other_things(val: *mut usize, normalref: &amp;usize) {
    let mutref = unsafe { val.as_mut().unwrap() };
    noaliases(normalref, mutref);
}

fn noaliases(input: &amp;usize, output: &amp;mut usize) {
    if *input &lt; 10 {
        *output = 15;
    }
    if *input > 10 {
        *output = 5;
    }
}

fn main() {
    uhoh();
}

having to go out of your way to learn it and religiously implement it.

Look! I painted the mona lisa in ketchup.

The cognitive load of writing safe C, and the volume of extra code it requires, is the problem of C.

Oh no, i'm having a meltdown with all the cognitive load...

Build all the fancy tools you want. At the end of the day if you put a monkey at the wheel of a Ferrari you'll still have problems.

Nice that Rust is memory-safe, use it if you want, but why the insistence on selling Rust via C is crap? Doesn't earn you any points.

How about rustaceans fork the kernel and once it's fully Rust-only then try and get it to be used instead of the current one... win-win, eh?

I’m not insisting anything; stating C is not a memory-safe language isn’t a subjective opinion.

Note I’m not even a Rust fan; I still prefer C because it’s what I know. But the kernel isn’t written by a bunch of Lewis Hamiltons; so many patches are from one-time contributors and the kernel continues to get inundated with memory safety bugs that no amount of infrastructure, testing, code review, etc is catching. Linux is written by monkeys with a few Hamiltons doing their best to review everything before merging.

Linus has talked about this repeatedly over the past few years at numerous conferences and there’s a reason he’s integrating Rust drivers and subsystems (and not asking them to fork as you are suggesting) to stop the kernel stagnating and to begin to address the issues like one-off patches that aren’t maintained by their original author and to start squashing the volume of memory corruption bugs that are causing 2/3rds of the kernel’s vulnerabilities.

the kernel continues to get inundated with memory safety bugs that no amount of infrastructure, testing, code review, etc is catching.

I'd say this is the issue to fix. It's not easy but if anything curl has proven it can be done efficiently.

Yeah, let's see what Bagder has to say about this:

C is unsafe and always will be

The C programming language is not memory-safe. Among the 150 reported curl CVEs, we have determined that 61 of them are “C mistakes”. Problems that most likely would not have happened had we used a memory-safe language. 40.6% of the vulnerabilities in curl reported so far could have been avoided by using another language.

Rust is virtually the only memory-safe language that is starting to become viable.

https://daniel.haxx.se/blog/2023/12/13/making-it-harder-to-do-wrong/

Memory safe language that's becoming viable ... as a proper replacement of C.

There are many other memory safe languages out there. Just not ones most would like to pull in to the kernel...

The vast majority wouldn't be able to be pulled into the kernel since they rely on the existence of the kernel via syscalls.

Yes a monkey. All the vulnerabilities that have happened over the decades are just bad c programmers. So the question is are there any good c programmers?

It's not just about bad/good C programmers. It's also about how much of the context, the given C programmer has read to make sure they know enough of what they are doing.

No matter how good one is at Programming, they need to make sure to read and remember what is happening in relevant parts of code, while making their one off contribution.

That's where the part of "leaving it to the computer" comes in. Hence, the usefulness of code checkers and even better if the compiler itself enforces the stuff. As long as the rules are good enough.

Let's just hope we are not jumping to another language 20 years down the line.

Anti Commercial-AI license

At the end of the day if you put a monkey at the wheel of a Ferrari you'll still have problems.

My eyes are rolling onto the floor and down the stairs.

I honestly like the cognitive load. Just not when I am at the workplace, having to deal with said load, with the office banter in the background and (not so) occasionally, being interrupted for other stuff.
And my cognitive load is not even about the memory allocations, most of the time.

Off topic:

I think, if one is seriously learning programming from a young age, it is better to start with C, make a project, big enough to feel the difficulty and understand what the cognitive load is all about and get used to it, hence increasing their mental capability. Then learn the memory safe language of their choice.
I never made a big enough project in C, but you can get to feel the load in C++ too.

Someone stubbed a toe here.

I think most people would agree with you, but that isn't really the issue. Rather the question is where the threshold for rewriting in Rust vs maintaining in C lies. Rewriting in any language is costly and error-prone, so at what point do the benefits outweigh that cost and risk? For a legacy, battle-tested codebase (possibly one of the most widely tested codebases out there), the benefit is probably on the lower side.

Isn't that exactly the strawman the maintainer got tired of?

Hmm... I admit I didn't follow the video and who was speaking very well and didn't notice hostility that others seem to pick up on. I've worked with plenty of people who turn childish when a technical discussion doesn't go their way, and I've had the luxury of mostly ignoring them, I guess.

It sounded like he was asking for deeper specification than others were willing or able to provide. That's a constant stalemate in software development. He's right to push for better specs, but if there aren't any then they have to work with what they've got.

My first response here was responding to the direct comparison of languages, which is kind of apples and oranges in this context, and I guess the languages involved aren't even really the issue.

Part of the hostility was the other maintainer misunderstanding the presenter, going on a diatribe about how the kernel Rust maintainers are going to force the C code to become unrefactorable and stagnate, and rudely interrupting the presenter with another tangent whenever he (the presenter) tried to clarify anything.

An unpleasant mix of DM railroading and gish galloping, essentially.

~~I wouldn't quite call it a strawman, but~~ the guy was clearly not engaging in good faith. He made up hypothetical scenarios that nobody asked about, and then denigrated Rust by attacking the scenarios he came up with.

Edit: I was thinking of the wrong fallacy. It is a strawman, yes.

He made up hypothetical scenarios that nobody asked about, and then denigrated Rust by attacking the scenarios he came up with.

This seems to be the textbook description of a strawman argument.

Wait, yeah. I was thinking of ad hominem when i wrote that, sorry. Correct, that is a strawman.

If the timeline is long enough then it's always worth the refactor.

Seeing as how 40% of the security issues that have been found over the years wouldn't exist in a memory-safe language, I would say a re-write is extremely worth it.

Maybe when you build some little application or whatever. When building the most used kernel in the world, there are probably some considerations that very few people can even try to understand.

What debate? You offered zero arguments and "C bad tho" isn't one.

Do you believe C isn't crap when it comes to security? Please explain why and I'll happily debate you.

/fw hacker, reverse engineer

That's not how it works. You said:

C is crap for anything where security matters.

Argue for your point.

Figure 2: https://sci-hub.se/https://link.springer.com/article/10.1007/s11416-021-00379-x

Lots of categories which Rust doesn't prevent, and in the kernel you'll end up with a lot of unsafe Rust, so it can't guarantee memory-safety in all cases.

The biggest items on the graph are all out of bounds accesses, use-after-free and overflows. It is undeniable that memory safe languages help reducing vulnerabilities, we know for decades that memory corruption vulnerabilities are both the most common and the most severe in programs written in memory-unsafe languages.

Unsafe rust is also not turning off every safety feature, and it's much better to have clear highlighted and isolated parts of code that are unsafe, which can be more easily reviewed and tested, compared to everything suffering from those problems.

I don't think there is debate here, rewriting is a huge effort, but the fact that using C is prone to memory corruption vulnerabilities and memory-safe languages are better from that regard is a fact.

Link dropping is also not arguing.

Citing scientific research is. Now, please post your gut feeling in response.

My gut feeling is you didn't hook a programmer but a debate pervert (maybe shouldn't have dropped the D word lol). Some people hear that word and turn they minds off cuz debates are simply a game for them to win. I'd just let this one swim brother

You continue to be antagonistic. I don't think I want to waste my time here.

C is crap for anything where security matters.

True for people misusing it. If you want to argue the ease of mis-use, it's a fun talk.

Yea, it's not C that is crap, but that it has zero guard rails. Like blaming a knife for not having a guard... Is it a bad knife without a guard? Depends on how sharp it is. The guard is orthogonal to the knife's purpose, but might still be important when the knife is used.

Just because something doesn't help prevent accidents does not mean it cannot serve its actual purpose well, unless its actual purpose is safety.

5 more...

Some next level deaf going on. That's not what was being discussed.

The defensiveness proves just how out of touch and unqualified to comment some people are.

5 more...

I feel like the time to hide information behind YouTube links is over. Feels like a link to a paywall article at this point.

RUST ppl feel like ARCH ppl. yes it might be better than some other setup yadda yadda, but they are so enervating.i'd rather switch back to windows11 than read another post/blog on how som crustians replaced this or that c library. just shut up already.

The sad thing is, there are other languages better at replacing C/C++ due to closer resemblance, except they're rarely used due to lack of trendy technology that is being hyped in Rust. D lost a lot of ground due to its maintainers didn't make it an "immutable by default" language at the time when functional programming paradigm was the next big thing in programming (which D can still do, as long as you're not too fussy about using const everywhere).

It was never about replacing C with a new language for the sake of novelty, it was about solving the large majority of security vulnerabilities that are inherent in memory-unsafe languages.

If Rust were to implode tomorrow, some other memory-safe language would come along and become equally annoying to developers who think they're the first and only person to suggest just checking the code really hard for memory issues before merge.

if you were right they'd replace it with Java.

Rust's memory safety is at compile-time. Java relies on a virtual machine and garbage collector. Nothing wrong with that approach but there's a reason Rust is used in kernels and Java is used in userspace apps.

Java was invented 20 years sooner.

Arch people tell you "I use arch BTW"

Rust people make PRs rewriting your code in rust.

Rust people are worse.

People are dumb as hell, it's fucking open source, go maintain the c fork, and let the those who want to improve the fucking shit cve producing codebase make a rust fork. And see which one people will use, and we all know that the rust fork will have wider adoption, it's a no brainer.

No one is forcing them to maintain the Linux kernel, no one is telling them to stop writing patches, they can't because you can download the code and work on it as you like.

It's people who know they will be irrelevant because they spent decades producing shit software, and they can't even be bothered to learn a new language to improve stability and security for the whole fucking userbase. Give me a break, what a bunch of whiners.

This is such a dumb take. For as much as I'd like to have a safer language in the kernel you need the current developers, the "big heads" at least because they have a lot of niche knowledge about their domains and how they implementation works (regardless of language) People shouldn't take shit like this from the ext4 developer, but it doesn't mean we should start vilifying all of them.

This guy's concerns are real and valid but were expressed with the maturity of a lunatic child, but they are not all like this.

If anything, the constant coddling of a few aging individuals within the kernel and the protection of their comforts is why Linux has been so slow to adopt technologies and paradigms that developers are begging for.

Linus complains of dev burnout starving the kernel of contributors, but the processes and technologies driving kernel development are antiquated, and the very suggestion of change is either discarded or makes you the target of a public shaming by Linus himself.

I agree with your views. But I have to give praise to Linus for bringing Rust into the kernel.

Yes and the big heads in this case don't want to share that knowledge, because why? Because they are treating the kernel like their pet project that they own and control, and they don't wanna lose that control, rather looking at the bigger picture.

It's kinda obvious that rust is the way forward as google has clearly shown, so why are they gatekeeping?

Yes I agree but the solution for a project so big and critical is not to fork. How do you maintain all of it while at the same time adding support to Rust?

There's no solution, they need not only to accept that rust is going to be part of the kernel but also that it's a good thing. Otherwise how do you cooperate efficiently.

And also if they are so big brained, should be easy to learn rust then, I mean I'm pretty small brained and I know rust.

"There's no compromise, I'M RIGHT AND YOU'RE WRONG!"

no wonder everyone hates rustphiles

Can we have a vegan rust sub, please?

What compromise? Half code should be in rust?

What does this even have to do with rust developers, The language rust gives us the ability to have more compile time checks, and why is that a bad thing. Do you like security issues in your OS because some dev forgot to handle pointers correctly?

The only compromise Rust programmers would accept is C programmers learn Rust so when they break Rust code they can fix it.

Dude what are you on about, there is no rust programmer that want to teach fucking rust to anyone who doesn't want learn...

This has nothing to do with C vs Rust, this has to do with security and enabling more people to develop stuff for Linux.

These so called kernel maintainers you see in the conference are only mainting the parts that they use for their filesystem, they are mainting the API, they are paid by companies who have sold support for ext4, xfs or brtfs etc.. . Of course they don't want to make their jobs any harder by learning a new language.

And of course they obfuscate the API with random naming and undocumented usage, because they want to make it hard for anyone else using trying to use the APIs.

If they don't want to be part of the improvement, then go do something else. Yes rust is better than C for this, because guess what - there are still CVEs being made, because it's impossible to catch everything with you eyes.

Now that's a conspiracy theory.

When did they refuse to share knowledge?

That was what he was talking about at the conference, he literally asked for help about how things work, so he could write better APIs that they are more comfortable using.

But the response was we don't want to write rust.

So what's the solution that doesn't involve C programmers writing Rust?

There's is no other way, C is a security issue - do you understand?

So you want to force C programmers to write Rust or GTFO.

No I want the OS that I use and my server to be less prone to security flaws. If you want to call that write rust or gtfo, so be it. But that is your words not mine, I'm more concerned with security

If you tell most linux developers to gtfo, then whatever is developed by the ones who are left is not mainline linux.

Are you born this way or are you chosing to be this way?

Goodbye

1 more...

It's people who know they will be irrelevant because they spent decades producing shit software

So the Linux kernel is shit software now? Just because it's not written in the newest programming language? Kind of a hot take.

No because it is buggy and have a bunch of security flaws.

Nobody can maintan a fork of the linux kernel on their own or even with a team. It's a HUGE task.

There already is rust in part of the linux kernel. It's not a fork.

But I agree with your first statement, people are dumb as hell, me included lol

No shit

Unix -> Linux -> Ferrix?

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old white man scared of losing their jobs or their commits going insigificant...who cares. Lets move on.

Lemmy comment not mentioning the race of someone challenge (IMPOSSIBLE)

the guy speaking off camera in the linked 3min 30s of the video is Ted Ts'o, according to this report about the session.

Losing their jobs? Uh what?