question about one of your ubuntu patch

[David Lee]

Hi Juerg,

Thanks for your reply. Very helpful to me.

We monitor the two closest upstream LTS kernels, 4.14 and 4.19 in this case.
And we periodically pull in commits from those two stable kernels into
bionic
4.15.

It seems that the task of tracking upstream is finished by one
person, Kamal Mostafa. Do you have some automatic tool or script
to help it faster?
Also, there is the webpage like this
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1889474 to say ubuntu
will port commits
from v4.14.190, v4.19.135. But there are some commits which are in these
two versions but not in the list of webpage.
Why these commits are filtered? Only because they do not have corresponding
backporting? Are these any rules to filter commits
from upstream?

Thanks

On Tue, Sep 1, 2020 at 5:13 AM Juerg Haefliger <
juerg.haefliger at canonical.com> wrote:

> On Tue, 11 Aug 2020 12:49:49 -0700
> David Lee <saynice111 at gmail.com> wrote:
>
> > Hi,
> >
> > Thanks for your reply. Very helpful to me.
> >
> > There is no upstream Linux 4.15 stable branch.
>
> Yes there is:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/log/?h=linux-4.15.y
>
>
> > There is no upstream linux 4.15 long term support branch. But there is a
> > Linux stable branch
> >
> https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/log/?h=linux-4.15.y
>
> Yes, what I said above.
>
>
> >
> > Ubuntu's bionic is based on Linux 4.15. But there is also linux
> 4.15-linux
> > 4.15.18 branch in ubuntu-bionic.
>
> There is no such branch in bionic:
> https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/bionic
>
>
> > And commits in Linux 4.15-4.15.18 in
> > ubuntu git is the same as it in Linux git except some ubuntu sauce
> patches.
>
> Bionic 4.15 contains all the commits from upstream 4.15.18 plus some more.
>
>
> > Besides, how does ubuntu know if there is a new patch added in upstream?
> > And how do ubuntu determine if a patch is necessary for ubuntu?
>
> We monitor the two closest upstream LTS kernels, 4.14 and 4.19 in this
> case.
> And we periodically pull in commits from those two stable kernels into
> bionic
> 4.15. We might end up pulling in commits that we don't really care about
> (because of configs we don't have enabled or architectures we don't
> support,
> or...) and sometimes we drop stable commits if they required substantial
> back-
> or forward-porting, unless we have clear evidence (bug reports) that
> they're
> absolutely needed/required.
>
> ...Juerg
>
>
>
> > Thanks
> >
> > On Tue, Aug 11, 2020 at 4:32 AM Thadeu Lima de Souza Cascardo <
> > cascardo at canonical.com> wrote:
> >
> > > On Tue, Aug 11, 2020 at 12:33:17AM -0700, David Lee wrote:
> > > > Hi,
> > > >
> > > > I saw your email in the patch "serdev: Fix serdev_uevent failure on
> ACPI
> > > > enumerated serdev-controllers
> 586ca5b1a90b66eb0a2805c9419683e33d1d418b"
> > > in
> > > > ubuntu's git repository.
> > > > I am surprised to find that this patch in ubuntu git is committed on
> Apr
> > > 12
> > > > 10:06:37 2018. But this patch is committed to linux 4.15 stable
> branch
> > > > on Apr 12 12:31:11 2018.
> > > > In ubuntu git repository, this patch is also in Linux 4.15 stable
> branch.
> > > > Why a patch is committed before it's added in Linux 4.15 stable
> branch?
> > > >
> > > > Thanks
> > >
> > > Hi, David.
> > >
> > > There is no upstream Linux 4.15 stable branch. Upstream kernel.org git
> > > trees
> > > closest to 4.15 are 4.14 and 4.19. Kamal Mostafa, from the Ubuntu
> Kernel
> > > team
> > > picks up commits from those trees in order to apply them to Ubuntu
> bionic
> > > kernel tree, which is based on 4.15. As upstream has stopped publishing
> > > updates
> > > to 4.15 and Ubuntu picked up 4.15 for its Bionic release, we have
> Kamal do
> > > the
> > > great job of tracking commits to 4.14 and 4.19 and make pull requests
> so
> > > those
> > > can be included in Ubuntu's kernel.
> > >
> > > But patches are also submitted to Ubuntu's kernel through other ways
> and
> > > for
> > > other reasons, like when they fix specific bugs tracked at launchpad.
> It
> > > may
> > > happen that such patches match upstream commits that have both landed
> on
> > > Kamal's tree and directly on Ubuntu's tree.
> > >
> > > And by git's distributed nature, the same patch may be applied on
> different
> > > dates, or it may happen that they are rebased or reapplied, causing
> them to
> > > have different commit ids, and even different commit dates or commit
> > > authors,
> > > or have had their messages changed because of sign-offs.
> > >
> > > I didn't investigate the specific case you pointed out, but it may be
> that
> > > with
> > > the explanations above, you may find other differences between those
> two
> > > commits that might explain what might have happened.
> > >
> > > Regards.
> > > Thadeu Cascardo.
> > >
>
>
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