Re: [PATCH v2 0/4] livepatch: Add garbage collection for shadow variables

Marcos Paulo de Souza
2023-01-23T17:35:12Z

On Tue, Nov 01, 2022 at 11:43:50AM +0100, Petr Mladek wrote:
> On Wed 2022-10-26 16:41:18, Marcos Paulo de Souza wrote:
> > Hello,
> >
> > This is the v2 of the livepatch shadow GC patches. The changes are minor since
> > nobody asked for for big code changes.
> >
> > Changes from v1:
> > * Reworked commit messages (Petr)
> > * Added my SoB which was missing in some patches, or the ordering was wrong. (Josh)
> > * Change __klp_shadow_get_or_use to __klp_shadow_get_or_add_locked and add a comment (Petr)
> > * Add lockdep_assert_held on __klp_shadow_get_or_add_locked (Petr)
> > about it's meaning (Petr)
> > * CCing LKML (Josh)
> >
> > Some observations:
> > * Petr has reviewed some of the patches that we created. I kept the Reviewed-by
> > tags since he wrote the patches some time ago and now he reviewed them again
> > on the ML.
> > * There were questions about possible problems about using klp_shadow_types
> > instead of using ids, but Petr already explained that internally it still uses
> > the id to find the correct livepatch.
> > * Regarding the possibility of multiple patches use the same ID, the problem
> > already existed before. Petr suggested using a "stringified" version using
> > name and id, but nobody has commented yet. I can implement such feature in a
> > v3 if necessary.
> >
> > Marcos Paulo de Souza (2):
> > livepatch/shadow: Introduce klp_shadow_type structure
> > livepatch/shadow: Add garbage collection of shadow variables
> >
> > Petr Mladek (2):
> > livepatch/shadow: Separate code to get or use pre-allocated shadow
> > variable
> > livepatch/shadow: Separate code removing all shadow variables for a
> > given id
>
> From my POV, the patchset is ready for pushing upstream.

Petr, what do you think about merging the first two patches, since they just
cleanups and simplifications?

>
> Well, we need to get approval from kpatch-build users. Joe described
> possible problems in replay for v3, see
> https://lore.kernel.org/r/b5fc2891-2fb0-4aa7-01dd-861da22bb7ea@redhat.com
>
> Best Regards,
> Petr