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

lkml.iu.edu

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

#181

Post by curveship »

magnetic wrote: post #137
chrisseaton wrote: post #113

Earlier quoted context omitted.

How do they handle bug fixing though? What if one application wants a bug fixed, but another application is depending on the bug inadvertently?

The bug they fix is the bug that keeps the API contract intact. The first application gets its bug fixed, and the second application breaks because it was relying on a bug that didn't match the API contract. You program to an API, not to an implementation. The second application did the latter, and will therefore pay the price.

That's not Linus' position. The "API contract" for the kernel is "we don't break userspace code," not "we don't break userspace code that follows the specs." He would bounce (and flame) the fix you're suggesting.

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

#182

Post by vidoc »

andyjohnson0 wrote: post #109
dingo_bat wrote: post #81

I'm always eager to read Linus's rants. I wish more of my coworkers were like him. I hate the environment where nobody reacts strongly to anything! If somebody fucks up hard and refuses to own up, I (or whoever's in charge) should be able to shout at them. It's only natural.

I disagree. To me he usually comes across as an asshole, albeit an extremely smart and accomplished one. A working environment where the person at the top can be relied upon to react to human failings with an aggressive, sweary [1] rant is not somewhere I ever want to work. [1] I'm aware that use of profanity in everyday speech is common in Finland. I don't mind swearing per se, but I find its over-use a bit tedious.

> [1] I'm aware that use of profanity in everyday speech is common in Finland. I don't mind swearing per se, but I find its over-use a bit tedious.

Actually what you are unaware of, might be that the use of profanity in everyday speech is actually very common pretty much anywhere in the world other than in the US&A where mince words and puritanism are still king.

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

#184

Post by phaemon »

lightedman wrote: post #149

"a return to a former or less developed state." See, it's the fact that Linus doesn't even know the real definition of 'regression' that makes me think I cant' trust him or anything he produces. That level of idiocy is simply intolerable.

It is a "less developed state". Software that worked, no longer works. That's what a software regression is.

The fact that you don't even understand the definition you quoted makes me...etc etc

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

#185

Post by goialoq »

jordigh wrote: post #152
bjourne wrote: post #42

John Johansen will survive. Linus has made it incredibly damn clear what "no user space regressions ever" mean. See f.e the similar rant from 2012: https://lkml.org/lkml/2012/12/23/75 And it is his kernel so it is his rules. John Johansen admitted he messed up ( http://lkml.iu.edu/hypermail/linux/kernel/1710.3/02539.html ) and promised to handle things better in the future so all is well.

> John Johansen will survive. We really need to stop excusing Linus's behaviour. Just because we may happen to agree with what he is saying doesn't mean we also have to agree with how he is saying it.

Everyone excused Johansen's behavior -- which broke Linux for users, until Linus stepped in and told Johansen to stop making excuses for hurting users. Johansen apologized for his mistake. Sniping at the team -- the people doing actual work -- from the sidelines is inappropriate

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

#186

Post by pjmlp »

tome wrote: post #135
pjmlp wrote: post #127

Earlier quoted context omitted.

All my favorite languages are typed and I do agree with him.

Really? How so? If you have abstract types then you can easily make internal changes without making those changes visible externally.

Some examples,

1 - Not all changes can be kept internal, for example adding a new case to an ADT

2 - Internal changes can still alter the semantic of the API, even if from the outside everything still looks the same from the type system point of view

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

#187

Post by goialoq »

stinos wrote: post #176
Karunamon wrote: post #168

Earlier quoted context omitted.

Disagree. It seems like Linus’ acerbic and direct means of communicating is the only thing keeping garbage code out of the kernel. He’s also made his views on “why not be nicer” well known. People need to get over it - his project, his rules. Plenty of other projects out there to hack on if getting yelled at when you disengage your brain is too much. Most of which don’t have the obsession with not breaking stuff for…

> acerbic and direct Isn't this just swearing? > the only thing keeping garbage code out of the kernel. I'm not sure if I'm buying that. It's possible, sure but on the other hand: It's not because the other way (i.e. communicating in a nice way, without all the swearing and direct attacks - which is imo not the same as direct communication ) hasn't been tried that somehow proves it won't work. E.g. I know repos where…

Do people who don't break users and lie about it get yelled at? Why are impolite words worse that actual harmful actions?

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

#188

Post by ams6110 »

lightedman wrote: post #172
bjourne wrote: post #42

John Johansen will survive. Linus has made it incredibly damn clear what "no user space regressions ever" mean. See f.e the similar rant from 2012: https://lkml.org/lkml/2012/12/23/75 And it is his kernel so it is his rules. John Johansen admitted he messed up ( http://lkml.iu.edu/hypermail/linux/kernel/1710.3/02539.html ) and promised to handle things better in the future so all is well.

"Linus has made it incredibly damn clear what "no user space regressions ever" mean." Absolute shame he doesn't even know the basic definition of 'regression' and uses the word incorrectly in every way. Breaking shit is simply breaking shit. It's not a regression unless something was broken first, then fixed, then the SAME ISSUE comes back in a later code change.

> basic definition of 'regression'

According to Linus: THE KERNEL NOT GIVING THE SAME END RESULT WITH THE SAME USER SPACE

According to Wikipedia: A software regression is a software bug that makes a feature stop functioning as intended after a certain event (for example, a system upgrade, system patching or a change to daylight saving time).

Seems like the two definitions are similar. There's no requirement that the defect be one that was seen earlier, fixed, and then reappears.

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

#189

Post by invokestatic »

leeoniya wrote: post #122
bjourne wrote: post #42

John Johansen will survive. Linus has made it incredibly damn clear what "no user space regressions ever" mean. See f.e the similar rant from 2012: https://lkml.org/lkml/2012/12/23/75 And it is his kernel so it is his rules. John Johansen admitted he messed up ( http://lkml.iu.edu/hypermail/linux/kernel/1710.3/02539.html ) and promised to handle things better in the future so all is well.

> Linus has made it incredibly damn clear what "no user space regressions ever" mean out of curiosity, how does a policy like this translate to microkernel OSes (e.g. Redox) where most everything runs in userspace?

Microkernels still need syscalls for usermode to interface with, so it is just as important. Kernels exist to serve userspace, not the other way around. Though, given the relative immaturity of Redox I assume this is less important compared to Linux.

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

#190

Post by jordigh »

Karunamon wrote: post #168
jordigh wrote: post #152

Earlier quoted context omitted.

> John Johansen will survive. We really need to stop excusing Linus's behaviour. Just because we may happen to agree with what he is saying doesn't mean we also have to agree with how he is saying it.

Disagree. It seems like Linus’ acerbic and direct means of communicating is the only thing keeping garbage code out of the kernel. He’s also made his views on “why not be nicer” well known. People need to get over it - his project, his rules. Plenty of other projects out there to hack on if getting yelled at when you disengage your brain is too much. Most of which don’t have the obsession with not breaking stuff for…

Matt Mackall, another cranky kernel hacker, showed me a lot about how it's possible to say "no" to many eager changes that would have broken Mercurial and not be yelling obscenities about it.

Linus is no role model. His imprecations are not what make Linux work.

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