Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A regression is the kernel not giving the same result with the same user space

lkml.iu.edu

Post reply on HN
Print view View original

21–30 of 408 posts

Re: A regression is the kernel not giving the same result with the same user space

#21

Post by bonzini »

delroth wrote: post #19

As much as I think the general principle of "no userspace visible change" is great, I can't make up my mind on whom I agree with the most in this specific instance. My understanding is that some distros (e.g. OpenSUSE) ship with AppArmor in a whitelist mode where things have to be explicitly permitted by policy, otherwise they're denied by default. AppArmor introduced a new class of actions that wasn't there before,…

It's not clear to me either. From John's replies it also seemed to be an OpenSUSE bug.

On the other hand, if it's bad enough it certainly makes sense to treat it as a kernel bug. The difficulty lies in finding where to draw the line.

Re: A regression is the kernel not giving the same result with the same user space

#22

Post by pjmlp »

jordigh wrote: post #4

Mercurial, made by another (in my opinion) much more well-spoken kernel hacker, is what really introduced me to the concept that you do not break interface for downstream users, no matter how wrongly you may think they are using the interface. It’s an attitude that is difficult to convey because software developers always want to have the freedom to “improve” their own software, even at the possible cost of breaking…

Rich Hickey has a wonderful talk about it.

"Spec-ulation" - https://www.youtube.com/watch?v=oyLBGkS5ICk

Which I fully agree with, basically there are no major, minor, patch level changes, in reality every change is a possible breaking changes, because we don't control what downstream is doing with our software.

Re: A regression is the kernel not giving the same result with the same user space

#23

Post by ptero »

OJFord wrote: post #12
bauerd wrote: post #10

Earlier quoted context omitted.

These are normative, not descriptive statements.

How is it normative? Although that's a bit of a rabbit hole, since presumably you won't allow me to appeal to the definition of 'normative'. Torvalds lambasts a developer for making a mistake, swears at him, and tells him the first rule of kernel development is that you don't make mistakes. Great.

He lambasts the developer not for making a mistake, but for making a mistake and refusing to admit that this is a mistake. That is very different.

Re: A regression is the kernel not giving the same result with the same user space

#25

Post by azernik »

OJFord wrote: post #7

> - we don't cause regressions Clearly false. > and the corollary is that when regressions do occur, we admit to them and fix them, instead of blaming user space. Clearly not a corollary...

We do not intentionally cause regressions, and if we do then we fix them instead of asking userspace to change.

Re: A regression is the kernel not giving the same result with the same user space

#26

Post by pjmlp »

_Codemonkeyism wrote: post #15
jordigh wrote: post #4

Mercurial, made by another (in my opinion) much more well-spoken kernel hacker, is what really introduced me to the concept that you do not break interface for downstream users, no matter how wrongly you may think they are using the interface. It’s an attitude that is difficult to convey because software developers always want to have the freedom to “improve” their own software, even at the possible cost of breaking…

For various reasons I would not go back to Java, but that was wonderful, your very old code still worked with newer versions, nothing broke during upgrades (even when behind deprecation one version).

We do enjoy breaking changes every now and then. :)

http://www.oracle.com/technetwork/java/javase/jdk-relnotes-i...

Of course, they are never at the level of a Python 3 release.

Re: A regression is the kernel not giving the same result with the same user space

#27

Post by teamhappy »

grenoire wrote: post #20
orcdork wrote: post #14

In any other kind of social/business arrangement he would be politely but firmly escorted out, possibly by security, for this kind of behavior. Being right or wrong is irrelevant.

You know what? I'm glad he is doing it this way. Hard to imagine the kernel getting to this point if he did not communicate and scrutinise like this.

> Hard to imagine the kernel getting to this point if he did not communicate and scrutinise like this.

Not hard to imagine at all. He could exercise the same amount of authority without losing his shit and would get exactly the same result.

It's one of his flaws and that's fine, but arguing that this kind of behaviour is somehow helpful is just ridiculous.

Re: A regression is the kernel not giving the same result with the same user space

#28

Post by stestagg »

orcdork wrote: post #14

In any other kind of social/business arrangement he would be politely but firmly escorted out, possibly by security, for this kind of behavior. Being right or wrong is irrelevant.

I can tell you, this sort of discussion happens in many Business settings, and doesn’t often end up involving security

Re: A regression is the kernel not giving the same result with the same user space

#29

Post by fdej »

jordigh wrote: post #4

Mercurial, made by another (in my opinion) much more well-spoken kernel hacker, is what really introduced me to the concept that you do not break interface for downstream users, no matter how wrongly you may think they are using the interface. It’s an attitude that is difficult to convey because software developers always want to have the freedom to “improve” their own software, even at the possible cost of breaking…

If only compiler developers had this attitude.

Re: A regression is the kernel not giving the same result with the same user space

#30

Post by _Codemonkeyism »

pjmlp wrote: post #26
_Codemonkeyism wrote: post #15

Earlier quoted context omitted.

For various reasons I would not go back to Java, but that was wonderful, your very old code still worked with newer versions, nothing broke during upgrades (even when behind deprecation one version).

We do enjoy breaking changes every now and then. :) http://www.oracle.com/technetwork/java/javase/jdk-relnotes-i... Of course, they are never at the level of a Python 3 release.

Yes, but compared to e.g. Scala breaking changes in Java are heaven, thanks :-)
Post reply on HN