4 ms·

Cynically, I’m thinking the main “problem” being solve here is the current drivers are not written in Rust

by weikju 3y ago

throwaway48476 3y ago
Unless the problem is memory safety, probably not.
- worthless-trash 3y ago
  There is another perspective you msy not be thinking of, developer availability In 20 years when the current crop of greybeards are dead, how many experienced c programmers with kernel experience will exist. Rust lowers the bar for contributing and also increases the pool of programmers who can.
  - sham1 3y ago
    I do somewhat doubt that. `no_std` Rust is still quite different from normal, userspace Rust. You don't get all the fancy libraries or whatever (of course Linus would probably just veto them anyway) and the Linux kernel development model is probably quite different (IIRC no cargo and whatnot). So… what should we reckon? Would there a difference in getting new developers into `no_std` Rust in the kernel, and how different would that be versus having people learn freestanding C, with all the kernel add-ons and nicknacks?
    - worthless-trash 3y ago
      Systems programming is always a full step sideways from traditional applications and I do see where you are coming from. I would still reckon that having familiarity with the standard rust (even with std) will still have more programmers willing to make the leap than learn C for this one project. I know of less than a handful of C projects starting in 2024, I know there is a bunch in rust , even with no_std.
    - charlotte-fyi 3y ago
      `no_std` with `alloc` isn't that different.
      - leoedin 3y ago
        Yeah it’s a weird take. The hard part about learning rust is borrow semantics and understanding the kinds of architectures the compiler will and won’t allow.
        sham1 3y ago
        Well maybe it's just me, but the borrow semantics were never all that bad. Of course there were things that needed to be relearnt, but it's not all that bad all things considered.
        SAI_Peregrinus 3y ago
        Coming from C, the borrow semantics are basically what I try to get anyway, violating them only with suspicion and great care. Rust just makes it easy to check that I didn't screw up what I was already trying to do.
  - anonzzzies 3y ago
    20 years is not a very long time and people are still learning c. My 17 year old intern learned c in college and prefers it over ‘modern crap’ (his words, but he wasn’t talking about rust; JavaScript). We do embedded (low powered mcu’s with a few kb of mem) and I too prefer c over rust for it; it’s a lot easier to attract c than rust people in my experience for this work. Most never touched rust and wouldn’t see a reason for it. Many of them are young.
    - kelnos 3y ago
      > My 17 year old intern learned c in college and prefers it over ‘modern crap’ I had a lot of opinions like this too when I was 17, but age and experience has disabused me of many of them. The embedded story on Rust still has many rough edges, but it's improving every day, and I could easily see it replace C in many places, given enough time (I wouldn't be too surprised if we eventually see companies distributing a BSP that's written in Rust). Frankly, at this point in time, I think it's foolish to start a new project in C unless you have a really good reason to do so. Many embedded systems certainly qualify as a really good reason, but I very much hope that reason diminishes over time.
      - consp 3y ago
        > wouldn't be too surprised if we eventually see companies distributing a BSP that's written in Rust Some niches maybe but most packages are ancient and the cost of supporting rust Vs the gain is massive. There are also way less people who can write rust. This forum with the "c is bad rust is the new God" attitude is not a representation of the world.
      - anonzzzies 3y ago
        > I had a lot of opinions like this too when I was 17, but age and experience has disabused me of many of them. Sure, I didn't say I agree with them, I barely remember when I was 17, it was that long ago. I'm saying that young people that I meet are more interested in c so the 'in 20 years no-one knows c' is not exactly true. We try Rust now and then; it's not worth it yet in my opinion for what we do. The tooling and libs we have for c are vast and like said, c people are really easy to get, Rust not so much. I hope this changes, but for now it's just too much of a struggle to warrant it. And I was only responding to the fear of not having capable c devs in 20 years. There will be plenty.
  - kelnos 3y ago
    > Rust lowers the bar for contributing Not sure I agree with that. C is a very easy language to learn. The problem with it is that you have to be careful with memory management. That does take effort to learn, and I still make mistakes after writing C for over 20 years. I love Rust, but it is a very complex language, with a complex, full-featured stdlib, and rich, sometimes-inscrutable type system. It is more difficult to learn than C, but also more difficult (and sometimes impossible) to make many of the mistakes that you can make in C.
    - littlestymaar 3y ago
      Rust isn't that hard to learn, and many of its user come from managed languages who never dared to learn C, because “it's too hard”. C looks easy on the surface, but the syntax is pretty dated and full of footguns (yes even just the syntax, not even talking about UBs), and learning the language is a pretty intimidating experience because every time you think you know something, you actually don't and get bitten later. Rust on the other hand is a good language for CS students: you have a lot of things to assimilate upfront, but when you've reached the level required to fulfill the class, you're actually ready to use it in production, and the resulting code produced by a sophomore will be more stable than C code written by wizards.
      - mananaysiempre 3y ago
        I know of two old syntactic footguns (assignment vs equality comparison; precedence of bitwise operators) and a single new one no one cares about (sizeof(int)+1 vs sizeof(int){+1}). The rest of the common bugbears look to be caused solely by bad pedagogy (the declaration syntax is not TYPE NAME; the switch statement is a computed goto not a multiarm conditional; there is no separate struct declaration). What am I missing?
    - unrealhoang 3y ago
      > C is a very easy language to learn. To learn the language, yes. Definitely not an easy language to learn to write production software in. Whereas an intermediate dev can easily get Rust basic in 2-3 months and can productively contribute to the safe portion of a complex project.
  - rjsw 3y ago
    > Rust lowers the bar for contributing and also increases the pool of programmers who can. It reduces the amount of help that current experienced kernel developers can give to newer developers who want to write in rust.
  - flohofwoe 3y ago
    That's a very optimistic view on the future of Rust, and a very pessimistic view on the future of C. Chances are that C will be longer around than Rust just because of the Lindy Effect ;)
  - littlestymaar 3y ago
    Yup, and that's exactly Linus' argument for Rust-in-Kernel.
  - xorcist 3y ago
    That argument is questionable. C is trivial. The PC architecture is not, and the Linux architecture absolutely not. What makes kernel programming hard is that there is a lot of knowledge that must be internalized, exactly how the DMA works for certain hardware, or why this specific bit need to be set in that lock. There's often no simple way of debugging or single stepping these things without simulating hardware. The kernel could have been written in assembly with macros, it wouldn't make its development any harder. The best Rust can do is not make kernel more difficult than it already is.
    - viraptor 3y ago
      You're missing on a lot of things Rust (or any language with non-toy types) can provide. Lock ordering, better accessible complex structures, enforcement of enumerated options, rich description of APIs, and many others. Atomic values are usable transparently https://github.com/AsahiLinux/linux/blob/97c628055904a7f2ef1f9318bb951b87f4cba21e/drivers/gpu/drm/asahi/queue/mod.rs#L400 https://github.com/AsahiLinux/linux/blob/97c628055904a7f2ef1... and multithreaded reference counting is easily enforced https://github.com/AsahiLinux/linux/blob/bd0a1a7d465fcb60685a2360565ed424bafff354/drivers/gpu/drm/asahi/channel.rs#L305 https://github.com/AsahiLinux/linux/blob/bd0a1a7d465fcb60685... also issues like type confusion https://www.vicarius.io/vsociety/posts/a-type-confusion-bug-in-nftseteleminit-leading-to-a-buffer-overflow https://www.vicarius.io/vsociety/posts/a-type-confusion-bug-... are less likely if you can easily use tagged unions checked by the compiler. The best Rust can do is enforce a number of invariants which people extremely experienced in writing "trivial C" still miss every day.
    - Barrin92 3y ago
      Linus himself made that point a few months ago (https://youtu.be/YyRVOGxRKLg https://youtu.be/YyRVOGxRKLg). If you take a look at how devoid large, important, old OSS projects are of young talent in their 20s, 30s and sometimes even 40s it's looking incredibly bleak. Rust is technically an improvement over memory unsafe language but it also has created enthusiam among largely young and proficient coders. The ecosystem has a lot of dynamism. Drawing those people in is one of the, if not the single most important thing for the health of projects going forward with how many leaders are close to retirement.
  - anthk 3y ago
    C? Any Teleco, and from the C++ crew, thousands of programmers can be used to C in days.
    - worthless-trash 3y ago
      Kernel C isn't userspace C. The bar for kernel C is much higher and less forgiving than userspace c. I can't talk about 'telco grade c', because I have never experienced it. I have however seen telco submitted code to upstream kernel and its not above the average quality.
- logicprog 3y ago
  Well, concerning memory safety, that might be a more important feature than you think. Allow me to quote a comment I just got an email notification for on a GNOME thread about NVIDIA: > I wish I could be more optimistic about mutter!3304 coming soon, though... it's been 5 months already, and it doesn't seem anywhere closer to being merged into main To make matters worse, patched mutter 45.5 seems to be causing use-after-free on NVIDIA's kernel driver.
- prussian 3y ago
  Honestly? Given I've seen crashes and printk messages from AMDGPU with words like "General Protection Fault," I'd say memory safety is probably the most important thing missing in these GPU drivers.
KingOfCoders 3y ago
My first thought too.
AtlasBarfed 3y ago
The cynicism if red hat is involved is that red hat wants more control of Linux. Christ could they just make Wayland usable first?
- sph 3y ago
  Please do not sidetrack this thread with Wayland flame bait.
- dralley 3y ago
  Wayland is usable, I've been using it for near 5 years.

Cynically, I’m thinking the main “problem” being solve here is the current drivers are not written in Rust

by weikju 3y ago

Cynically, I’m thinking the main “problem” being solve here is the current drivers are not written in Rust

throwaway48476 3y ago

Unless the problem is memory safety, probably not.

worthless-trash 3y ago
There is another perspective you msy not be thinking of, developer availability In 20 years when the current crop of greybeards are dead, how many experienced c programmers with kernel experience will exist. Rust lowers the bar for contributing and also increases the pool of programmers who can.
- sham1 3y ago
  I do somewhat doubt that. `no_std` Rust is still quite different from normal, userspace Rust. You don't get all the fancy libraries or whatever (of course Linus would probably just veto them anyway) and the Linux kernel development model is probably quite different (IIRC no cargo and whatnot). So… what should we reckon? Would there a difference in getting new developers into `no_std` Rust in the kernel, and how different would that be versus having people learn freestanding C, with all the kernel add-ons and nicknacks?
  - worthless-trash 3y ago
    Systems programming is always a full step sideways from traditional applications and I do see where you are coming from. I would still reckon that having familiarity with the standard rust (even with std) will still have more programmers willing to make the leap than learn C for this one project. I know of less than a handful of C projects starting in 2024, I know there is a bunch in rust , even with no_std.
  - charlotte-fyi 3y ago
    `no_std` with `alloc` isn't that different.
    - leoedin 3y ago
      Yeah it’s a weird take. The hard part about learning rust is borrow semantics and understanding the kinds of architectures the compiler will and won’t allow.
      - sham1 3y ago
        Well maybe it's just me, but the borrow semantics were never all that bad. Of course there were things that needed to be relearnt, but it's not all that bad all things considered.
        SAI_Peregrinus 3y ago
        Coming from C, the borrow semantics are basically what I try to get anyway, violating them only with suspicion and great care. Rust just makes it easy to check that I didn't screw up what I was already trying to do.
- anonzzzies 3y ago
  20 years is not a very long time and people are still learning c. My 17 year old intern learned c in college and prefers it over ‘modern crap’ (his words, but he wasn’t talking about rust; JavaScript). We do embedded (low powered mcu’s with a few kb of mem) and I too prefer c over rust for it; it’s a lot easier to attract c than rust people in my experience for this work. Most never touched rust and wouldn’t see a reason for it. Many of them are young.
  - kelnos 3y ago
    > My 17 year old intern learned c in college and prefers it over ‘modern crap’ I had a lot of opinions like this too when I was 17, but age and experience has disabused me of many of them. The embedded story on Rust still has many rough edges, but it's improving every day, and I could easily see it replace C in many places, given enough time (I wouldn't be too surprised if we eventually see companies distributing a BSP that's written in Rust). Frankly, at this point in time, I think it's foolish to start a new project in C unless you have a really good reason to do so. Many embedded systems certainly qualify as a really good reason, but I very much hope that reason diminishes over time.
    - consp 3y ago
      > wouldn't be too surprised if we eventually see companies distributing a BSP that's written in Rust Some niches maybe but most packages are ancient and the cost of supporting rust Vs the gain is massive. There are also way less people who can write rust. This forum with the "c is bad rust is the new God" attitude is not a representation of the world.
    - anonzzzies 3y ago
      > I had a lot of opinions like this too when I was 17, but age and experience has disabused me of many of them. Sure, I didn't say I agree with them, I barely remember when I was 17, it was that long ago. I'm saying that young people that I meet are more interested in c so the 'in 20 years no-one knows c' is not exactly true. We try Rust now and then; it's not worth it yet in my opinion for what we do. The tooling and libs we have for c are vast and like said, c people are really easy to get, Rust not so much. I hope this changes, but for now it's just too much of a struggle to warrant it. And I was only responding to the fear of not having capable c devs in 20 years. There will be plenty.
- kelnos 3y ago
  > Rust lowers the bar for contributing Not sure I agree with that. C is a very easy language to learn. The problem with it is that you have to be careful with memory management. That does take effort to learn, and I still make mistakes after writing C for over 20 years. I love Rust, but it is a very complex language, with a complex, full-featured stdlib, and rich, sometimes-inscrutable type system. It is more difficult to learn than C, but also more difficult (and sometimes impossible) to make many of the mistakes that you can make in C.
  - littlestymaar 3y ago
    Rust isn't that hard to learn, and many of its user come from managed languages who never dared to learn C, because “it's too hard”. C looks easy on the surface, but the syntax is pretty dated and full of footguns (yes even just the syntax, not even talking about UBs), and learning the language is a pretty intimidating experience because every time you think you know something, you actually don't and get bitten later. Rust on the other hand is a good language for CS students: you have a lot of things to assimilate upfront, but when you've reached the level required to fulfill the class, you're actually ready to use it in production, and the resulting code produced by a sophomore will be more stable than C code written by wizards.
    - mananaysiempre 3y ago
      I know of two old syntactic footguns (assignment vs equality comparison; precedence of bitwise operators) and a single new one no one cares about (sizeof(int)+1 vs sizeof(int){+1}). The rest of the common bugbears look to be caused solely by bad pedagogy (the declaration syntax is not TYPE NAME; the switch statement is a computed goto not a multiarm conditional; there is no separate struct declaration). What am I missing?
  - unrealhoang 3y ago
    > C is a very easy language to learn. To learn the language, yes. Definitely not an easy language to learn to write production software in. Whereas an intermediate dev can easily get Rust basic in 2-3 months and can productively contribute to the safe portion of a complex project.
- rjsw 3y ago
  > Rust lowers the bar for contributing and also increases the pool of programmers who can. It reduces the amount of help that current experienced kernel developers can give to newer developers who want to write in rust.
- flohofwoe 3y ago
  That's a very optimistic view on the future of Rust, and a very pessimistic view on the future of C. Chances are that C will be longer around than Rust just because of the Lindy Effect ;)
- littlestymaar 3y ago
  Yup, and that's exactly Linus' argument for Rust-in-Kernel.
- xorcist 3y ago
  That argument is questionable. C is trivial. The PC architecture is not, and the Linux architecture absolutely not. What makes kernel programming hard is that there is a lot of knowledge that must be internalized, exactly how the DMA works for certain hardware, or why this specific bit need to be set in that lock. There's often no simple way of debugging or single stepping these things without simulating hardware. The kernel could have been written in assembly with macros, it wouldn't make its development any harder. The best Rust can do is not make kernel more difficult than it already is.
  - viraptor 3y ago
    You're missing on a lot of things Rust (or any language with non-toy types) can provide. Lock ordering, better accessible complex structures, enforcement of enumerated options, rich description of APIs, and many others. Atomic values are usable transparently https://github.com/AsahiLinux/linux/blob/97c628055904a7f2ef1f9318bb951b87f4cba21e/drivers/gpu/drm/asahi/queue/mod.rs#L400 https://github.com/AsahiLinux/linux/blob/97c628055904a7f2ef1... and multithreaded reference counting is easily enforced https://github.com/AsahiLinux/linux/blob/bd0a1a7d465fcb60685a2360565ed424bafff354/drivers/gpu/drm/asahi/channel.rs#L305 https://github.com/AsahiLinux/linux/blob/bd0a1a7d465fcb60685... also issues like type confusion https://www.vicarius.io/vsociety/posts/a-type-confusion-bug-in-nftseteleminit-leading-to-a-buffer-overflow https://www.vicarius.io/vsociety/posts/a-type-confusion-bug-... are less likely if you can easily use tagged unions checked by the compiler. The best Rust can do is enforce a number of invariants which people extremely experienced in writing "trivial C" still miss every day.
  - Barrin92 3y ago
    Linus himself made that point a few months ago (https://youtu.be/YyRVOGxRKLg https://youtu.be/YyRVOGxRKLg). If you take a look at how devoid large, important, old OSS projects are of young talent in their 20s, 30s and sometimes even 40s it's looking incredibly bleak. Rust is technically an improvement over memory unsafe language but it also has created enthusiam among largely young and proficient coders. The ecosystem has a lot of dynamism. Drawing those people in is one of the, if not the single most important thing for the health of projects going forward with how many leaders are close to retirement.
- anthk 3y ago
  C? Any Teleco, and from the C++ crew, thousands of programmers can be used to C in days.
  - worthless-trash 3y ago
    Kernel C isn't userspace C. The bar for kernel C is much higher and less forgiving than userspace c. I can't talk about 'telco grade c', because I have never experienced it. I have however seen telco submitted code to upstream kernel and its not above the average quality.
logicprog 3y ago
Well, concerning memory safety, that might be a more important feature than you think. Allow me to quote a comment I just got an email notification for on a GNOME thread about NVIDIA: > I wish I could be more optimistic about mutter!3304 coming soon, though... it's been 5 months already, and it doesn't seem anywhere closer to being merged into main To make matters worse, patched mutter 45.5 seems to be causing use-after-free on NVIDIA's kernel driver.
prussian 3y ago
Honestly? Given I've seen crashes and printk messages from AMDGPU with words like "General Protection Fault," I'd say memory safety is probably the most important thing missing in these GPU drivers.

KingOfCoders 3y ago

My first thought too.

AtlasBarfed 3y ago

The cynicism if red hat is involved is that red hat wants more control of Linux. Christ could they just make Wayland usable first?

sph 3y ago
Please do not sidetrack this thread with Wayland flame bait.
dralley 3y ago
Wayland is usable, I've been using it for near 5 years.