Re: [BUG] New Kernel Bugs

Linus Torvalds
2007-11-14T19:55:09Z

On Wed, 14 Nov 2007, Nick Piggin wrote:
>
> Not if you said their regression causing patches will get reverted unless it
> can be fixed for release.

Actually, I'm pretty happy reverting patches that cause regressions even
if it *can* be "fixed for release". If there isn't a fix available within
a day or two, it should get reverted.

The "fix" can then be re-applying the *fixed* patch - and at that point we
should strive to require the person who re-submits the patch (with fixes)
having to have an Ack from the person who found the problem in the first
place, so that it's verified to actually fix things!

So I really would encourage people to send me emails like

Please revert commit xyz, because it breaks abc, and there is no
fix available even though this was reported x days ago.

I have verified that revert just that change fixes the issue.

and just make the "because it breaks abc" be specific and clear enough
that I go "Ahh, ok, I'd better revert it".

Also, please notice the latter part of the suggestion above: even if
somebody has bisected down their problem to a specific commit, I really
*do* want to hear that actually undoing the commit on top of the current
tree acually fixes it again, because sometimes that just isn't the case -
sometimes you end up having various interactions that means that reverting
a commit might simply not even work.

I have no trouble at all with reverting commits in general. I think
regressions are serious.

So the problematic cases are the cases where:

- the commit no longer reverts cleanly, or just otherwise introduces
other infrastructure that other commits that already got merged depend
on.

So sometimes you actually need a patch along with the revert (Andrew
does that kind of thing anyway, since he works with patches regardless,
so the "needs a patch" case is obviously not limited to just the
problem cases)

- more commonly: it's not entirely clear which commit actually caused the
problem.

but I *do* want to encourage people to revert (and ask other people to
revert) much more aggressively. I personally try to revert things that
people report regressions to me about very actively, unless I know
somebody already has or is working on a fix.

Linus