On Thu, Apr 16, 2020 at 04:08:10AM +0000, Saeed Mahameed wrote: > On Wed, 2020-04-15 at 20:00 -0400, Sasha Levin wrote: > > On Wed, Apr 15, 2020 at 05:18:38PM +0100, Edward Cree wrote: > > > Firstly, let me apologise: my previous email was too harsh and too > > > assertiveabout things that were really more uncertain and unclear. > > > > > > On 14/04/2020 21:57, Sasha Levin wrote: > > > > I've pointed out that almost 50% of commits tagged for stable do > > > > not > > > > have a fixes tag, and yet they are fixes. You really deduce > > > > things based > > > > on coin flip probability? > > > Yes, but far less than 50% of commits *not* tagged for stable have > > > a fixes > > > tag. It's not about hard-and-fast Aristotelian "deductions", like > > > "this > > > doesn't have Fixes:, therefore it is not a stable candidate", it's > > > about > > > probabilistic "induction". > > > > > > > "it does increase the amount of countervailing evidence needed to > > > > conclude a commit is a fix" - Please explain this argument given > > > > the > > > > above. > > > Are you familiar with Bayesian statistics? If not, I'd suggest > > > reading > > > something like http://yudkowsky.net/rational/bayes/ which explains > > > it. > > > There's a big difference between a coin flip and a _correlated_ > > > coin flip. > > > > I'd maybe point out that the selection process is based on a neural > > network which knows about the existence of a Fixes tag in a commit. > > > > It does exactly what you're describing, but also taking a bunch more > > factors into it's desicion process ("panic"? "oops"? "overflow"? > > etc). > > > > I am not against AUTOSEL in general, as long as the decision to know > how far back it is allowed to take a patch is made deterministically > and not statistically based on some AI hunch. > > Any auto selection for a patch without a Fixes tags can be catastrophic > .. imagine a patch without a Fixes Tag with a single line that is > fixing some "oops", such patch can be easily applied cleanly to stable- > v.x and stable-v.y .. while it fixes the issue on v.x it might have > catastrophic results on v.y .. I tried to imagine such flow and failed to do so. Are you talking about anything specific or imaginary case? <...> > > > > Let me put my Microsoft employee hat on here. We have > > driver/net/hyperv/ > > which definitely wasn't getting all the fixes it should have been > > getting without AUTOSEL. > > > > until some patch which shouldn't get backported slips through, believe > me this will happen, just give it some time .. Bugs are inevitable, I don't see many differences between bugs introduced by manually cherry-picking or automatically one. Of course, it is true if this automatically cherry-picking works as expected and evolving. > > > While net/ is doing great, drivers/net/ is not. If it's indeed > > following > > the same rules then we need to talk about how we get done right. > > > > both net and drivers/net are managed by the same maitainer and follow > the same rules, can you elaborate on the difference ? The main reason is a difference in a volume between net and drivers/net. While net/* patches are watched by many eyes and carefully selected to be ported to stable@, most of the drivers/net patches are not. Except 3-5 the most active drivers, rest of the driver patches almost never asked to be backported. Thanks
