Re: [3.0-stable PATCH 00/36] Proposed 3.0-stable bug patches

Ben Myers
2012-12-07T21:13:13Z

Hey,

On Fri, Dec 07, 2012 at 09:06:47PM +1100, Dave Chinner wrote:
> On Thu, Dec 06, 2012 at 11:27:22AM -0600, Mark Tinguely wrote:
> > On 12/05/12 15:45, Dave Chinner wrote:
> > >On Mon, Dec 03, 2012 at 05:42:08PM -0600, Mark Tinguely wrote:
> > >>Here a collection of bug fixes for 3.0-stable. Many of these patches
> > >>were also selected by Dave Chinner as possible 3.0-stable patches:
> > >> http://oss.sgi.com/archives/xfs/2012-08/msg00255.html
> > >>
> > >>I chose only bug fixes and kept the changes to a minimum.
> > >>
> > >>Patch 21/22 are required for the bug fix in patch 23 but they are
> > >>important changes in their own right.
> > >
> > >So I'll ask the same question that Christoph asked me: If nobody is
> > >reporting problems on 3.0.x, why do this and risk regression and
> > >fallout that requires fixing?
> > >
> > >FWIW, what testing have you done?
> >
> > Do you mean?
> >
> > http://oss.sgi.com/archives/xfs/2012-09/msg00002.html
> >
> > I read that message as a concern that your original Linux 3.0-stable
> > patch series contained some items that did not meet the -stable
> > criteria.
>
> I read it as "why change something that no-one is reporting bugs
> for?".

I guess we could all stop putting words in his mouth and let him speak for
himself. Christoph (cc'd), would you please clarify your position?

> I posted that series because I had to do the work for RHEL to
> address customer reported problems, not because I felt like pushing
> a bunch of fixes back to 3.0.
>
> I've spent quite a bit of time over the past few weeks dealing with
> various weird regressions as a result of that backport. If you're
> going to backport a singificant amount of stuff to 3.0.x, then
> that's what you are signing up for. i.e. doing all the bug triage
> and fixing that will result from the backport...
>
> > As for adding patches to 3.0-stable. I believed then and now that
> > proactively suggesting bug fixes into 3.0-stable is a good thing
> > because it is the long term stable branch.
>
> Which is in direct contrast to what most of us think. That is, if
> nobody is reporting problems, then it ain't broke and it doesn't
> need fixing.

Who are you speaking for?

In my opinion, proposing appropriate bug fixes for inclusion in -stable has
merit regardless of whether the bug has been reported by -stable users. If the
fix fits the -stable criteria and there is a chance a stable user will hit the
bug it can be proposed.

> > A few days after Christoph's email, I put my "Reviewed-by:" on your
> > series.
> >
> > http://oss.sgi.com/archives/xfs/2012-09/msg00167.html
> >
> > As for testing, the whole series is spun on xfstests loops for days on
> > x86_32 and x86_64 boxes, just like we test a top of tree patch series.
>
> Which we all know does not catch all possible regressions. What
> about crash/shutdown testing? Or load/stress testing?

I have no objection to additional testing of proposed -stable patches. However
I believe it is impossible to catch 'all possible regressions'. There will
always be some risk here.

> /me is playing Devil's Advocate because I'm not signing up to
> triage a whole new set of 3.0.x stable kernel regressions when
> nobody is currently reporting problems.....

SGI XFS product is based directly upon -stable branches and I'd like to track
these branches as closely as possible. This aligns the interests of the SGI
XFS team and -stable users. If there are regressions, myself, Mark, Phil,
Rich, and Andrew are signed up to fix them regardless of whether you wish to be
involved. Paying customers come first as always, but the bugs will be fixed
either way.

Stable folk (cc'd Greg), what is your disposition with regard to proposing
patches for -stable proactively? Do we really need to have a bug report from a
3.0-stable user for every bug we propose for 3.0-stable?

Thanks,
Ben