Re: [PATCH v3 7/8] objtool/klp: Correlate locals to globals

[Song Liu]

On Thu, Mar 5, 2026 at 11:51 AM Josh Poimboeuf <jpoim...@kernel.org> wrote:
>
> On Wed, Feb 25, 2026 at 04:54:35PM -0800, Song Liu wrote:
> > Allow correlating original locals to patched globals, and vice versa.
> > This is needed when:
> >
> > 1. User adds/removes "static" for a function.
> > 2. CONFIG_LTO_CLANG_THIN promotes local functions and objects to global
> >    and add .llvm.<hash> suffix.
> >
> > Given this is a less common scenario, show warnings when this is needed.
> >
> > Signed-off-by: Song Liu <s...@kernel.org>
> > ---
> >  tools/objtool/klp-diff.c | 34 ++++++++++++++++++++++++++++++++++
> >  1 file changed, 34 insertions(+)
> >
> > diff --git a/tools/objtool/klp-diff.c b/tools/objtool/klp-diff.c
> > index 92043da0ed0b..5cda965807a5 100644
> > --- a/tools/objtool/klp-diff.c
> > +++ b/tools/objtool/klp-diff.c
> > @@ -517,6 +517,40 @@ static int correlate_symbols(struct elfs *e)
> >               }
> >       }
> >
> > +     /* Correlate original locals with patched globals */
> > +     for_each_sym(e->orig, sym1) {
> > +             if (sym1->twin || dont_correlate(sym1) || !is_local_sym(sym1))
> > +                     continue;
> > +
> > +             sym2 = find_global_symbol_by_name(e->patched, sym1->name);
> > +             if (!sym2 && find_global_symbol_by_demangled_name(e->patched, 
> > sym1, &sym2))
> > +                     return -1;
> > +
> > +             if (sym2 && !sym2->twin) {
> > +                     sym1->twin = sym2;
> > +                     sym2->twin = sym1;
> > +                     WARN("correlate LOCAL %s (original) to GLOBAL %s 
> > (patched)",
> > +                          sym1->name, sym2->name);
>
> I think this correlation is deterministic so there's no need for the
> warning?

Yes, we can remove this.

I also fixed 1/8 and 3/8. I will send v4 of patch 1/8 to 7/8, as we discuss
more with 8/8.

Thanks,
Song