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

Petr Mladek
2022-11-01T10:43:55Z

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.

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