On Wed, Jun 10, 2026 at 11:11 PM Petr Mladek <[email protected]> wrote:
>
> On Sun 2026-06-07 21:16:56, Yafang Shao wrote:
> > stack_order is no longer needed for atomic-replace livepatches, as a
> > single function can only be modified by a unique replace_set.
> > To maintain backward compatibility, print a dummy value, as suggested by
> > sashiko-bot.
>
> I would personally remove it completely. I believe that there are
> only few users around the world. And they will need to update
> the tooling/strategy for the new "replace_set" anyway.

I will remove it completely in the next version.

>
> > --- /dev/null
> > +++ b/Documentation/ABI/removed/sysfs-kernel-livepatch
> > @@ -0,0 +1,9 @@
> > +What:                /sys/kernel/livepatch/<patch>/stack_order
> > +Date:                Jan 2025
> > +KernelVersion:       6.14.0
> > +Description:
> > +             This attribute specifies the sequence in which live patch 
> > modules
> > +             are applied to the system. If multiple live patches modify 
> > the same
> > +             function, the implementation with the biggest 'stack_order' 
> > number
> > +             is used, unless a transition is currently in progress.
>
> I was not aware of this ABI/removed part. We should put here also
> the livepatch/replace interface which was removed in the 3rd patch.

sure

>
> > --- a/tools/testing/selftests/livepatch/test-sysfs.sh
> > +++ b/tools/testing/selftests/livepatch/test-sysfs.sh
> > @@ -21,8 +21,6 @@ check_sysfs_rights "$MOD_LIVEPATCH" "enabled" "-rw-r--r--"
> >  check_sysfs_value  "$MOD_LIVEPATCH" "enabled" "1"
> >  check_sysfs_rights "$MOD_LIVEPATCH" "force" "--w-------"
> >  check_sysfs_rights "$MOD_LIVEPATCH" "replace" "-r--r--r--"
> > -check_sysfs_rights "$MOD_LIVEPATCH" "stack_order" "-r--r--r--"
> > -check_sysfs_value  "$MOD_LIVEPATCH" "stack_order" "1"
> >  check_sysfs_rights "$MOD_LIVEPATCH" "transition" "-r--r--r--"
> >  check_sysfs_value  "$MOD_LIVEPATCH" "transition" "0"
> >  check_sysfs_rights "$MOD_LIVEPATCH" "vmlinux/patched" "-r--r--r--"
> > @@ -135,71 +133,4 @@ livepatch: '$MOD_LIVEPATCH': completing unpatching 
> > transition
> >  livepatch: '$MOD_LIVEPATCH': unpatching complete
> >  % rmmod $MOD_LIVEPATCH"
> >
> > -start_test "sysfs test stack_order value"
> > -
>
> This is not longer needed in linux-next. Marcos made the test optional,
> see
> https://lore.kernel.org/all/[email protected]/

Thanks for sharing.

>
> The changes are queued for 7.2 merge window which will likely start
> next week.
>
> I suggest to wait with v4 until the change is merged. We should wait
> for opinion from others (Miroslav, Josh, Joe, Song) anyway. We
> need to be sure that the change of the semantic is acceptable
> in general.

Understood. I'll wait for further feedback.

>
>
> > -load_lp $MOD_LIVEPATCH
> > -
> > -check_sysfs_value  "$MOD_LIVEPATCH" "stack_order" "1"
> > -
> > -load_lp $MOD_LIVEPATCH2
> > -
> > -check_sysfs_value  "$MOD_LIVEPATCH2" "stack_order" "2"
> > -
> > -load_lp $MOD_LIVEPATCH3
>
> Nit: It seems that MOD_LIVEPATCH2 and MOD_LIVEPATCH3 are not longer used
>      at least in this test-sysfs.sh file. Well, I guess that we will
>      keep this test optional for older kernels.
>
> > -check_sysfs_value  "$MOD_LIVEPATCH3" "stack_order" "3"
> > -
>
> Best Regards,
> Petr



-- 
Regards
Yafang

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