On Thu, Apr 19, 2018 at 04:22:22PM +0200, Greg KH wrote: > On Thu, Apr 19, 2018 at 04:05:45PM +0200, Jan Kara wrote: > > On Thu 19-04-18 15:59:43, Greg KH wrote: > > > On Thu, Apr 19, 2018 at 02:41:33PM +0300, Thomas Backlund wrote: > > > > Den 16-04-2018 kl. 19:19, skrev Sasha Levin: > > > > > On Mon, Apr 16, 2018 at 12:12:24PM -0400, Steven Rostedt wrote: > > > > > > On Mon, 16 Apr 2018 16:02:03 +0000 > > > > > > Sasha Levin <Alexander.Levin@xxxxxxxxxxxxx> wrote: > > > > > > > > > > > > > One of the things Greg is pushing strongly for is "bug compatibility": > > > > > > > we want the kernel to behave the same way between mainline and stable. > > > > > > > If the code is broken, it should be broken in the same way. > > > > > > > > > > > > Wait! What does that mean? What's the purpose of stable if it is as > > > > > > broken as mainline? > > > > > > > > > > This just means that if there is a fix that went in mainline, and the > > > > > fix is broken somehow, we'd rather take the broken fix than not. > > > > > > > > > > In this scenario, *something* will be broken, it's just a matter of > > > > > what. We'd rather have the same thing broken between mainline and > > > > > stable. > > > > > > > > > > > > > Yeah, but _intentionally_ breaking existing setups to stay "bug compatible" > > > > _is_ a _regression_ you _really_ _dont_ want in a stable > > > > supported distro. Because end-users dont care about upstream breaking > > > > stuff... its the distro that takes the heat for that... > > > > > > > > Something "already broken" is not a regression... > > > > > > > > As distro maintainer that means one now have to review _every_ patch that > > > > carries "AUTOSEL", follow all the mail threads that comes up about it, then > > > > track if it landed in -stable queue, and read every response and possible > > > > objection to all patches in the -stable queue a second time around... then > > > > check if it still got included in final stable point relase and then either > > > > revert them in distro kernel or go track down all the follow-up fixes > > > > needed... > > > > > > > > Just to avoid being "bug compatible with master" > > > > > > I've done this "bug compatible" "breakage" more than the AUTOSEL stuff > > > has in the past, so you had better also be reviewing all of my normal > > > commits as well :) > > > > > > Anyway, we are trying not to do this, but it does, and will, > > > occasionally happen. > > > > Sure, that's understood. So this was just misunderstanding. Sasha's > > original comment really sounded like "bug compatibility" with current > > master is desirable and that made me go "Are you serious?" as well... > > As I said before in this thread, yes, sometimes I do this on purpose. > > As an specific example, see a recent bluetooth patch that caused a > regression on some chromebook devices. The chromeos developers > rightfully complainied, and I left the commit in there to provide the > needed "leverage" on the upstream developers to fix this properly. > Otherwise if I had reverted the stable patch, when people move to a > newer kernel version, things break, and no one remembers why. > > I also wrote a long response as to _why_ I do this, and even though it > does happen, why it still is worth taking the stable updates. Please > see the archives for the full details. I don't want to duplicate this > again here. And to be more specific, let's always take this as a case-by-case basis. The last time this happened was the bluetooth bug and it was a fix for a reported problem, but then the fix caused a regression so upstream reverted it and I reverted it in the stable trees. No matter what I chose to do, someone would be upset so I followed what upstream did. thanks, greg k-h