Re: Patches potentially missing from stable releases

[Sasha Levin <sashal@kernel.org>]

On Tue, Aug 27, 2019 at 01:01:51PM -0700, Guenter Roeck wrote:
>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

I was referring to things that say that they "fixes:", but the fix it
not stable material (typos, fallthrough, etc).

>make sense to start with looking at Fixes: ? After all, additional
>references (wich higher chance for false positives) can always be
>searched for later.

Yes, let me send a branch out for review later today and we could
compare our results.

--
Thanks,
Sasha