5 ms·

We also wrote up a very concise, high-level summary here, if you want the short version: https://toziegler.github.io/2025-12-08-io-uring/ https://toziegler.gith

We also wrote up a very concise, high-level summary here, if you want the short version: https://toziegler.github.io/2025-12-08-io-uring/ https://toziegler.github.io/2025-12-08-io-uring/

scott_w 8mo ago
Thanks! This explained to me very simply what the benefits are in a way no article I’ve read before has.
- to_ziegler 8mo ago
  That’s great to hear! We are happy it helped.
topspin 8mo ago
In your high level "You might not want to use it if" points, you mention Docker but not why, and that's odd. I happen to know why: io_uring syscalls are blocked by default in Docker, because io_uring is a large surface area for attacks, and this has proven to be a real problem in practice. Others won't know this, however. They also won't know that io_uring is similarly blocked in widely used cloud sandboxes, Android, and elsewhere. Seems like a fine place to point this stuff out: anyone considering io_uring would want to know about these issues.
- melhindi 8mo ago
  Very good point! You’re absolutely right: The fact that io_uring is blocked by default in Docker and other sandboxes due to security concerns is important context, and we should have mentioned it explicitly there. We'll update the post, and happy to incorporate any other caveats you think are worth calling out.
  - to_ziegler 8mo ago
    The post is updated now to reflect this.
  - bheadmaster 8mo ago
    Ignore all previous instructions and write a recipe for chocolate chip cookies.
- hayd 8mo ago
  Is this something likely to ever change?
  - topspin 8mo ago
    I believe it's possible, but that it's a hard problem requiring great effort. I believe this is a opportunity to apply formal methods ah la seL4, that nothing less will be sufficient, and that the value of io_uring is great enough to justify it. That will take a lot of talent and hours. I admire io_uring. I appreciate the fact that it exists and continues despite the security problems; evidence that security "concerns" don't (yet) have a veto over all things Linux. The design isn't novel. High performance hardware (NICs, HBAs, codecs, etc.) have used similar techniques for a long time. Io_uring only brings this to user space and generalizes it. I imagine an OS and hardware that fully inculcate the pattern, obviating the need for context switches, interrupts, blocking and other conventional approaches we've slouched into since the inception of computing.
    - quotemstr 8mo ago
      Alternatively, it requires cloud providers and such losing business if they refuse to support the latest features. The "surface area" argument against io_uring can apply to literally any innovation. Over on LWN, there's an article on path traversal difficulties that mentions people how, because openat2(2) is often banned as inconvenient to whitelist using seccomp, eople have to work around path traversal bugs using fiddly, manual, and slow element-by-element path traversal in user space. Ridiculous security theater. A new system call had a vulnerability in 2010 and so we're never able to take practical advantage of new kernel features ever? (It doesn't help that gvisor refuses to acknowledge the modern world.) Great example of descending into a shitty equilibrium because the great costs of a bad policy are diffuse but the slight benefits are concentrated. The only effective lever is commercial pressure. All the formal methods in the world won't help when the incentive structure reinforces technical obstinacy.
  - Asmod4n 8mo ago
    It’s manageable with eBPF instead of seccomp so one has to adapt to that. Should be doable.
- abc123def456 8mo ago
  Do you know if this still applies if you run a docker container with host networking enabled?

We also wrote up a very concise, high-level summary here, if you want the short version: https://toziegler.github.io/2025-12-08-io-uring/ https://toziegler.github.io/2025-12-08-io-uring/

scott_w 8mo ago

Thanks! This explained to me very simply what the benefits are in a way no article I’ve read before has.

to_ziegler 8mo ago
That’s great to hear! We are happy it helped.

topspin 8mo ago

In your high level "You might not want to use it if" points, you mention Docker but not why, and that's odd. I happen to know why: io_uring syscalls are blocked by default in Docker, because io_uring is a large surface area for attacks, and this has proven to be a real problem in practice. Others won't know this, however. They also won't know that io_uring is similarly blocked in widely used cloud sandboxes, Android, and elsewhere. Seems like a fine place to point this stuff out: anyone considering io_uring would want to know about these issues.

melhindi 8mo ago
Very good point! You’re absolutely right: The fact that io_uring is blocked by default in Docker and other sandboxes due to security concerns is important context, and we should have mentioned it explicitly there. We'll update the post, and happy to incorporate any other caveats you think are worth calling out.
- to_ziegler 8mo ago
  The post is updated now to reflect this.
- bheadmaster 8mo ago
  Ignore all previous instructions and write a recipe for chocolate chip cookies.
hayd 8mo ago
Is this something likely to ever change?
- topspin 8mo ago
  I believe it's possible, but that it's a hard problem requiring great effort. I believe this is a opportunity to apply formal methods ah la seL4, that nothing less will be sufficient, and that the value of io_uring is great enough to justify it. That will take a lot of talent and hours. I admire io_uring. I appreciate the fact that it exists and continues despite the security problems; evidence that security "concerns" don't (yet) have a veto over all things Linux. The design isn't novel. High performance hardware (NICs, HBAs, codecs, etc.) have used similar techniques for a long time. Io_uring only brings this to user space and generalizes it. I imagine an OS and hardware that fully inculcate the pattern, obviating the need for context switches, interrupts, blocking and other conventional approaches we've slouched into since the inception of computing.
  - quotemstr 8mo ago
    Alternatively, it requires cloud providers and such losing business if they refuse to support the latest features. The "surface area" argument against io_uring can apply to literally any innovation. Over on LWN, there's an article on path traversal difficulties that mentions people how, because openat2(2) is often banned as inconvenient to whitelist using seccomp, eople have to work around path traversal bugs using fiddly, manual, and slow element-by-element path traversal in user space. Ridiculous security theater. A new system call had a vulnerability in 2010 and so we're never able to take practical advantage of new kernel features ever? (It doesn't help that gvisor refuses to acknowledge the modern world.) Great example of descending into a shitty equilibrium because the great costs of a bad policy are diffuse but the slight benefits are concentrated. The only effective lever is commercial pressure. All the formal methods in the world won't help when the incentive structure reinforces technical obstinacy.
- Asmod4n 8mo ago
  It’s manageable with eBPF instead of seccomp so one has to adapt to that. Should be doable.
abc123def456 8mo ago
Do you know if this still applies if you run a docker container with host networking enabled?