Re: Patches potentially missing from stable releases

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Aug 27, 2019 at 02:10:03PM -0400, Sasha Levin wrote:
> On Tue, Aug 27, 2019 at 10:16:21AM -0700, Guenter Roeck wrote:
> >Hi,
> >
> >I recently wrote a script which identifies patches potentially missing
> >in downstream kernel branches. The idea is to identify patches backported/
> >applied to a downstream branch for which patches tagged with Fixes: are
> >available in the upstream kernel, but those fixes are missing from the
> >downstream branch. The script workflow is something like:
> >
> >- Identify locally applied patches in downstream branch
> >- For each patch, identify the matching upstream SHA
> >- Search the upstream kernel for Fixes: tags with this SHA
> >- If one or more patches with matching Fixes: tags are found, check
> > if the patch was applied to the downstream branch.
> >- If the patch was not applied to the downstream branch, report
> >
> >Running this script on chromeos-4.19 identified, not surprisingly, a number
> >of such patches. However, and more surprisingly, it also identified several
> >patches applied to v4.19.y for which fixes are available in the upstream
> >kernel, but those fixes have not been applied to v4.19.y. Some of those
> >are on the cosmetic side, but several seem to be relevant. I didn't
> >cross-check all of them, but the ones I tried did apply to linux-4.19.y.
> >The complete list is attached below.
> >
> >Question: Do Sasha's automated scripts identify such patches ? If not,
> >would it make sense to do it ? Or is there some reason why the patches
> >have not been applied to v4.19.y ?
> 
> Hey Guenter,
> 
> I have a very similar script with a slight difference: I don't try to
> find just "Fixes:" tags, but rather just any reference from one patch to
> another. This tends to catch cases where once patch states it's "a
> similar fix to ..." and such.
> 
> The tricky part is that it's causing a whole bunch of false positives,
> which takes a while to weed through - and that's where the issue is
> right now.
> 

I didn't see any false positives, at least not yet. Would it possibly
make sense to start with looking at Fixes: ? After all, additional
references (wich higher chance for false positives) can always be
searched for later.

Thanks,
Guenter

> I try to review a few each week and queue them up together with my
> autosel patches, but I guess I should step it up a bit.
> 
> Let me go over my list and try to catch up - I think I'll have time in
> the very near future.
> 
> --
> Thanks,
> Sasha