4 ms·

Best explanation I found is here: https://lore.kernel.org/stable/CAFsF8vL4CGFzWMb38_XviiEgxoKX0GYup=JiUFXUOmagdk9CRg@mail.gmail.com/ https://lore.kernel.org/st

Best explanation I found is here: https://lore.kernel.org/stable/CAFsF8vL4CGFzWMb38_XviiEgxoKX0GYup=JiUFXUOmagdk9CRg@mail.gmail.com/ https://lore.kernel.org/stable/CAFsF8vL4CGFzWMb38_XviiEgxoKX... A patch was backported to the 6.0 branch from the main branch, but they forgot a line of code, leading to a buggy behavior.

yjftsjthsd-h 4y ago
So that might suggest that it's actually better to just track the latest version, rather than worrying about backports?
- CJefferson 4y ago
  In my (limited) experience, the only reason to use backports is because you have closed source kernel modules which you can't update (that of course ends up covering most Android phones, and many SOCs)
  - touisteur 4y ago
    There's also official support of vmm things like firecracker, which officially supports only 5.10 and maybe latest but don't send bugs?
- ilyt 4y ago
  Distros standardize on version not because it is more stable but because tooling (which might include 3rd party modules for the kernel) can then rely to work on that version without recompile. If you don't have that constraint yeah, not much reason.
- eklitzke 4y ago
  The vast majority of the time fixes like this that are being backported are straightforward fixes for bugs (security or otherwise) that require very little manual conflict resolution, especially if the fix is just being backported one or two kernel releases. The developer can often just cherry-pick the commit into a few recent release branches and most of the time git will just automatically do the merge correctly, or if there is a manual merge conflict it's something really simple. In fact, if there's a complicated merge conflict often the change won't be backported at all unless the bug is actually serious enough to warrant X hours of someone's time to do it and get code review etc. Most of the time this process works correctly, but obviously there's room for error and mistakes can happen. There's a tradeoff between the risk of running an older kernel that has known bugs, upgrading to the latest new kernel which has bug fixes but may introduce new bugs, and getting backports for known bugs to your known working kernel. Most of the time the last option is reasonable but it definitely depends on your use case and what you're optimizing for.
vfclists 4y ago
This soooo BASIC!! Why aren't the processes either manual or automated in place to check for things like this? Aren't there some tests in place to check for such basic functionality errors? Doesn't kernel development process mandate much facilities? I'm sure the NSA, Unit 8200 and GCHQ have tests like this in place but don't share their findings. Is it a matter of funding or leadership philosophy and priorities?
- cdelsolar 4y ago
  yeah right? doesn't the kernel have a test suite?
  - bonzini 4y ago
    Every kernel subsystem has its own testsuite. Running all of them would requires hundreds of different pieces of hardware, so it's not really possible for a single release manager to do so. For Linus's releases this is easily solved by slowing down progressively the pace of development towards a release, so that cross-subsystem issues where maintainer A breaks maintainer B's subsystem become progressively less likely over the two months of the release cycle. For stable releases this is much harder to do because of the short cycle. The stable branches in the end are a mostly automated collection of patches based on both maintainer input and the output of a machine learning model. The quality of stable branches is generally pretty good, or screwups such as this one would not make a headline; but that's more a result of discipline of mainline kernel development, rather than a virtue of the stable kernel release process.
    - vfclists 4y ago
      > Running all of them would requires hundreds of different pieces of hardware, so it's not really possible for a single release manager to do so. The issue is this bug is not hardware related. Its a pure software issue. Hardware bugs are an entirely different kettle of fish. BTW is that bonzini of GNU Smalltalk fame?
      - 4y ago
bravetraveler 4y ago
I'll open by saying I'll forever be thankful for GKH... but this response kills me: > As 6.0.y is now end-of-life, is there anything keeping you on that kernel tree? Uh, several distributions. It wasn't EOL enough to prevent breaking it, so fix it. Don't even technically need their input, Git and all. I'll buy this EOL thing if they revert the change that caused this and stop releasing under 6.0. There were at least two more after this
- Arnavion 4y ago
  >Uh, several distributions. That is the kernel bug tracker, not the distributions bug tracker. >It wasn't EOL enough to prevent breaking it, so fix it. It wasn't EOL at the time the patch was backported. It's EOL now. >I'll buy this EOL thing if they revert the change that caused this and stop releasing under 6.0. There were at least two more after this Not sure what "this" in "two more after this" is, but there have been no 6.0 releases since it was EOLed.
  - bravetraveler 4y ago
    > That is the kernel bug tracker, not the distributions bug tracker. The point is that the contributors reasoning for being on the tree is irrelevant. Like you said, they just made it EOL Distributions are the continuous/constant answer as to why countless people will be. This isn't an ancient release, something from the grave. Is the expectation, then, that distributions would have to patch out the regression - or take on a more major upgrade (6.1 / 6.2), likely breaking something else? Neither of these are particularly tenable. I'm glad GKH was willing to accept further changes to make it correct, but reverting is also applicable. Breaking something, calling it EOL, and not fixing it is closer to dead than end of life.
    - Arnavion 4y ago
      >Is the expectation, then, that distributions would have to patch out the regression - or take on a more major upgrade (6.1 / 6.2), likely breaking something else? Correct. >Neither of these are particularly tenable. Yes they are. >Breaking something, calling it EOL, and not fixing it is closer to dead than end of life. You're awfully confident about how things should work, even though you don't understand how they already work.

yjftsjthsd-h 4y ago

So that might suggest that it's actually better to just track the latest version, rather than worrying about backports?

CJefferson 4y ago
In my (limited) experience, the only reason to use backports is because you have closed source kernel modules which you can't update (that of course ends up covering most Android phones, and many SOCs)
- touisteur 4y ago
  There's also official support of vmm things like firecracker, which officially supports only 5.10 and maybe latest but don't send bugs?
ilyt 4y ago
Distros standardize on version not because it is more stable but because tooling (which might include 3rd party modules for the kernel) can then rely to work on that version without recompile. If you don't have that constraint yeah, not much reason.
eklitzke 4y ago
The vast majority of the time fixes like this that are being backported are straightforward fixes for bugs (security or otherwise) that require very little manual conflict resolution, especially if the fix is just being backported one or two kernel releases. The developer can often just cherry-pick the commit into a few recent release branches and most of the time git will just automatically do the merge correctly, or if there is a manual merge conflict it's something really simple. In fact, if there's a complicated merge conflict often the change won't be backported at all unless the bug is actually serious enough to warrant X hours of someone's time to do it and get code review etc. Most of the time this process works correctly, but obviously there's room for error and mistakes can happen. There's a tradeoff between the risk of running an older kernel that has known bugs, upgrading to the latest new kernel which has bug fixes but may introduce new bugs, and getting backports for known bugs to your known working kernel. Most of the time the last option is reasonable but it definitely depends on your use case and what you're optimizing for.

vfclists 4y ago

This soooo BASIC!! Why aren't the processes either manual or automated in place to check for things like this? Aren't there some tests in place to check for such basic functionality errors? Doesn't kernel development process mandate much facilities? I'm sure the NSA, Unit 8200 and GCHQ have tests like this in place but don't share their findings. Is it a matter of funding or leadership philosophy and priorities?

cdelsolar 4y ago
yeah right? doesn't the kernel have a test suite?
- bonzini 4y ago
  Every kernel subsystem has its own testsuite. Running all of them would requires hundreds of different pieces of hardware, so it's not really possible for a single release manager to do so. For Linus's releases this is easily solved by slowing down progressively the pace of development towards a release, so that cross-subsystem issues where maintainer A breaks maintainer B's subsystem become progressively less likely over the two months of the release cycle. For stable releases this is much harder to do because of the short cycle. The stable branches in the end are a mostly automated collection of patches based on both maintainer input and the output of a machine learning model. The quality of stable branches is generally pretty good, or screwups such as this one would not make a headline; but that's more a result of discipline of mainline kernel development, rather than a virtue of the stable kernel release process.
  - vfclists 4y ago
    > Running all of them would requires hundreds of different pieces of hardware, so it's not really possible for a single release manager to do so. The issue is this bug is not hardware related. Its a pure software issue. Hardware bugs are an entirely different kettle of fish. BTW is that bonzini of GNU Smalltalk fame?
    - 4y ago

bravetraveler 4y ago

I'll open by saying I'll forever be thankful for GKH... but this response kills me: > As 6.0.y is now end-of-life, is there anything keeping you on that kernel tree? Uh, several distributions. It wasn't EOL enough to prevent breaking it, so fix it. Don't even technically need their input, Git and all. I'll buy this EOL thing if they revert the change that caused this and stop releasing under 6.0. There were at least two more after this

Arnavion 4y ago
>Uh, several distributions. That is the kernel bug tracker, not the distributions bug tracker. >It wasn't EOL enough to prevent breaking it, so fix it. It wasn't EOL at the time the patch was backported. It's EOL now. >I'll buy this EOL thing if they revert the change that caused this and stop releasing under 6.0. There were at least two more after this Not sure what "this" in "two more after this" is, but there have been no 6.0 releases since it was EOLed.
- bravetraveler 4y ago
  > That is the kernel bug tracker, not the distributions bug tracker. The point is that the contributors reasoning for being on the tree is irrelevant. Like you said, they just made it EOL Distributions are the continuous/constant answer as to why countless people will be. This isn't an ancient release, something from the grave. Is the expectation, then, that distributions would have to patch out the regression - or take on a more major upgrade (6.1 / 6.2), likely breaking something else? Neither of these are particularly tenable. I'm glad GKH was willing to accept further changes to make it correct, but reverting is also applicable. Breaking something, calling it EOL, and not fixing it is closer to dead than end of life.
  - Arnavion 4y ago
    >Is the expectation, then, that distributions would have to patch out the regression - or take on a more major upgrade (6.1 / 6.2), likely breaking something else? Correct. >Neither of these are particularly tenable. Yes they are. >Breaking something, calling it EOL, and not fixing it is closer to dead than end of life. You're awfully confident about how things should work, even though you don't understand how they already work.