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@microsoft.com 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