Messages in this thread | | | Date | Tue, 16 Jul 2013 13:29:27 -0700 (PDT) | From | David Lang <> | Subject | Re: [Ksummit-2013-discuss] When to push bug fixes to mainline |
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On Tue, 16 Jul 2013, H. Peter Anvin wrote:
> On 07/16/2013 12:19 AM, David Lang wrote: >> On Fri, 12 Jul 2013, Willy Tarreau wrote: >> >>> And maybe in the end, having 1/10 patch cause a regression is not *that* >>> dramatic, and probably less than not fixing the 9 other bugs. In one case >>> we rely on -stable to merge the 10 fixes, and on the other case we'd rely >>> on -stable to just revert one of them. >> >> Apologies for the late post, I'm catching up on things, but this jumped >> out at me. >> >> We went through a LOT of pain several years ago when people got into the >> mindset that a patch was acceptable if it fixed more people than it >> broke. eliminating that mindset did wonders for kernel stability. >> >> Regressions are a lot more of a negative than bugfixes are a positive, a >> 10:1 ratio of fixes to regressions is _not_ good enough. >> > > In my opinion, there is one exception, and that is when the problem > being fixed is much more severe than the fix. *In particular* two > cases: permanently damaging hardware and corrupting data. For example: > no boot, as severe as it is, is much better than either of these two > scenarios.
True, but the key point of this subthread is that regressions are _really_ bad, and in practice it's impossible to do enough testing to guarantee that there aren't regressions.
as a result, you should only risk regressions if the problem that is being fixed is really important. Just because someone found a bug doesn't make it important enough to risk regressions over.
David Lang
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