Re: [patch 2/2] Documentation/process: Add tip tree handbook

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Nov 08, 2018 at 01:06:15PM -0800, Greg KH wrote:
> On Thu, Nov 08, 2018 at 08:58:32PM +0100, Thomas Gleixner wrote:
> > On Thu, 8 Nov 2018, Paul E. McKenney wrote:
> > > On Thu, Nov 08, 2018 at 09:19:33AM -0800, Dan Williams wrote:
> > > > On Thu, Nov 8, 2018 at 1:13 AM Peter Zijlstra <peterz@infradead.org> wrote:
> > > > >
> > > > > On Thu, Nov 08, 2018 at 08:40:12AM +0100, Ingo Molnar wrote:
> > > > > > > + - Cc: ``cc-ed-person <person@mail>``
> > > > > > > +
> > > > > > > +   If the patch should be backported to stable, then please add a '``Cc:
> > > > > > > +   stable@vger.kernel.org``' tag, but do not Cc stable when sending your
> > > > > > > +   mail.
> > > > > >
> > > > > > Can I suggest a more canonical form:
> > > > > >
> > > > > >       Cc: <stable@vger.kernel.org> # v4.18 and later kernels
> > > > > >
> > > > > > It would be nice if people adding Cc: stable lines would actually try to
> > > > > > figure out which exact kernel versions are affected.
> > > > 
> > > > I know at least StGit mail does not grok that "#"notation. I've
> > > > stopped using it in favor of a "Fixes:" tag. I would think "Fixes:" is
> > > > preferred over "# <KVER>" if only because it can be used to track
> > > > fixes to commits that have been backported to stable. Is there any
> > > > reason for "# <KVER>" to continue in a world where we have "Fixes:"?
> > > 
> > > I sometimes have fixes that need to be different for different past
> > > releases.  And there have been cases where RCU patches would apply and
> > > build cleanly against releases for which it was not appropriate, but
> > > would have some low-probability failure.  Which meant that it could be
> > > expected to pass light testing.  :-/
> > > 
> > > So I sometimes need a way of saying which versions a given patch applies
> > > to, independent of the version into which the bug was introduced.
> > 
> > I can understand that you want to limit the scope of automatic backports.
> > 
> > But we really should try to always use of the Fixes: tag. In most cases the
> > SHA1 of the commit in the fixes tag defines the backport scope. 
> > 
> > For the rare cases where the buggy commit is really old, but you want to
> > limit the backport scope for a reason then I really like to avoid to
> > overload the Cc stable tag and have a dedicated tag instead. Something
> > like:
> > 
> >     Fixes: 1234567890AB ("subsys/comp: Short summary")
> >     Backport-to: 4.14
> 
> Ick, no.  Just stick to the "Fixes:" tag.  My scripts can now track when
> a patch is backported to a stable tree so that I know to apply it to
> older ones despite the original patch showing up in a newer release.
> 
> And yes, those scripts are new, as Sasha is about to point out all of
> the places where I missed this in the past :)

Here's the script if others are curious:
	https://github.com/gregkh/gregkh-linux/blob/master/scripts/fix_in_what_release

Yes, I know it's horrid, I abuse the fact that 'git grep' is very fast
on the stable-queue repo :)

thanks,

greg k-h