Many good summaries of the Linux kernel userspace compatibility policy are available. Search for them.
A regression is the kernel not giving the same result with the same user space
11–20 of 408 posts
Re: A regression is the kernel not giving the same result with the same user space
#12> - 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...
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.
Re: A regression is the kernel not giving the same result with the same user space
#13Earlier 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.
>we should not cause regressions
>and the corollary is that when regressions do occur, we should admit to them and fix them, instead of blaming user space
Clearly he is aware that they did cause a regression as the mailing list post he responds to would not exist otherwise. Reading these two statements descriptively renders him an idiot.
Re: A regression is the kernel not giving the same result with the same user space
#14In 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.
Re: A regression is the kernel not giving the same result with the same user space
#15Mercurial, 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).
Re: A regression is the kernel not giving the same result with the same user space
#16In 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.
Linus or the contributor? I can see an argument for either.
Re: A regression is the kernel not giving the same result with the same user space
#17Linus being salty is like soap opera for HN.
Pleasant and good mannered application programmers gasp when real men (aka systems programmers) communicate at each other.
Re: A regression is the kernel not giving the same result with the same user space
#18Earlier 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.
[deleted]
Re: A regression is the kernel not giving the same result with the same user space
#19As 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, and with these restrictive policies it's causing daemons to crash (because it gets auto-denied).
The whole point of these policies is to not expose new attack surface if it's not needed by the software. It's going to break whenever AppArmor will start supporting more checks, unless policies get pinned to a specific version of AppArmor. But AppArmor doesn't currently support this (they refer to it as "features ABI" in the thread).
WAI?
Re: A regression is the kernel not giving the same result with the same user space
#20In 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.