Linus is pretty big on kernel updates not breaking userland it's been the topic of several flames. Not that that's perfect or a guarantee but it is a priority among the devs.
It's probably safe since rolling release distributions upgrade just the kernel and work fine. I'd watch out for the graphics drivers though--sometimes you need to recompile them with the new kernel headers or just use the DKMS version.
I've bought new laptop recently with Kaby Lake processor and put Ubuntu 17.04 on it, so the kernel upgrade was kind of necessity. No adverse effects observed, and on the plus side: somewhat better battery life, Asus USB-C docking station working correctly, including Gigabit Ethernet port, resolved issues with sleep/resume.
Dell XPS 13 (9360). I know, they sell those with Ubuntu pre-installed, but they are hard to come by in my country, so i bought Win10 version and installed Linux myself
It can happen. There are a bunch of bots that do regression tests, Fedora's Rawhide provides daily debug builds of the kernel with merges in-between the rc's, so there are are some real humans also using the kernel through its development. If you check the 4.11.1 changelog as an example you can see the kinds of things that can crop up. Fedora current releases tend to rebase around x.y.2. So you could use that as a way to weigh your kernel conservatism.
So maybe a stupid question for me - but since all the answers here say that new kernels generally don't break userland, then... what do I get from an update? Security fixes? Faster syscalls? Because otherwise I can't think of changes that would affect me in any way without updating rest of the userland.
Major distros backport security fixes. I'd say improved hardware support is 90% the reason to upgrade to a new kernel. Algorithmic improvements (like bfq) and new syscalls/subsystems are infrequent and one might not be able to make use of them immediately unless libs/userland adapt quickly.
Linus Torvalds breaks into a childish tantrum of (edit: correction: swearing rants are technically coherent), public swearing at people whenever anyone anywhere in Linux kernel development breaks any userspace app. As a consequence, userspace regressions are rare.
(Might contain traces of hyperbole—still; Linus' behaviour is largely unacceptable nonetheless)
Linus is very well known for his rants, but you've definitely mischaracterized them. He's seldom incoherent, and the ones that are vulgar enough to make for juicy sensationalized "news" are only ever directed at contributors who are experienced enough to know better than to break userspace or something badly wrong like that. His more level-headed corrections of well-meaning inexperienced developers don't make the news.
I'm not seeing where the ire was directed at anybody new. The two messages Linus sent were in reply to a pull request from Dave Airlie, a very high-level and extremely experienced developer. Daniel Vetter tried to chastise Linus for chewing out some new contributor named Noralf, but it appears that the real problem is that the problems with Noralf's code went unfixed by intermediaries like Vetter and Airlie and made it all the way to Linus.
The kernel shouldn't let bad code into the tree just because the author is inexperienced. Subsystem maintainers are supposed to be a very thorough filter, so that the patches reaching Linus are up to standard. When bad code makes it to Linus, it's his job to complain about it. And based on that thread, it looks like he was complaining about it, and was not directing the complaints at the original author but at the people who were responsible for reviewing and testing the code.
To me it reads like redirecting blame to the contributor by appearing to "defend" him. Linus was obviously replying (and chastising) the person who sent him the code, and who was supposed to review it beforehand, not the original author.
You might not like his method of cat-herding, but historically, it has worked pretty well. That summarizes the way I feel about them.
It is a time-tested leadership method to make an example out of a hapless mistake-maker to keep the rest of the herd in line. And it isn't like that sort of thing doesn't happen in the corporate world; it is just that corporate dressings down (down-dressings?) don't happen on public mailing lists.
Not my preferred tactic, but in the odd world of Linux kernel development, it certainly works.
I think Linus' method of communication is unnecessarily coarse and sometimes abusive.
I also think that the scant, ineffectual pushback against his unprofessionalism-- especially when considering the fame and size of the Linux community-- serves to emphasize the much greater significance of his "don't break userspace" dogma.
"Don't break userspace" keeps developers from rationalizing regressions as a necessary step in the service of progress.
"Don't break userspace" allows little players to leverage Linux without worrying about a big player making problems (purposely or not) for their use case.
"Don't break userspace" keeps big players from leveraging usage statistics as a weapon against little players.
"Don't break userspace" has probably streamlined development discussion during every tenuous period in Linux' history by taking a class of bikeshedding off the table.
"Don't break userspace" neutralizes paranoiacs who would otherwise conclude that fixing a broken interface was really just an excuse for [insert three letter government agency here] to [insert insidious plan here].
"Don't break userspace" essentially disarms the entire Linux community and provides a path to a surprisingly fast development cycle.
If you think I'm exaggerating, look at the outrage against systemd where the (development community) rhetoric isn't nearly as coarse or abusive. Or even look at the discussion on the SVG list around Chromium deprecating the awful SMIL interface (which was never even in IE or Edge and never will be). You would have thought Google was was suspending habeus corpus for all the rhetoric around that decision.
That is how important "don't break userspace" is to a healthy, functioning development model. Have only that and a license like the GPLv2 and you can apparently choose the least professional communication style-- littered with cursewords and personal insults-- and still maintain one of the most successful open source communities in the world.
I think you're conflating two different things. Yes, Linus is very strict about not breaking userspace. But the swearing doesn't come from some void somewhere: it is directly aimed at enforcing the rules of not breaking userspace.
If Linus didn't occasionally get angry about it the people below wouldn't take it as seriously, and the kernel wouldn't as stable a target.
you can apparently choose the least professional communication style-- littered with cursewords and personal insults
This is silly. Linus has written (tens of?) thousands of completely "professional" messages. A few outbursts over the 25 years of kernel development are not a choice of "the least professional communication style".
M code isn't up to snuff, but I still check the mailing lists - just to see his rage manifest. As near as I can tell, you're mostly okay so long as you don't break userspace. Mostly...
They are a beautiful thing. People may not like it, but the efficacy is beyond doubt.
