Re: [PATCH 11/48] objtool/klp: Fix handling of zero-length .altinstr_replacement sections

[Josh Poimboeuf]

On Fri, Apr 24, 2026 at 02:19:52PM -0700, Song Liu wrote:
> On Wed, Apr 22, 2026 at 9:05 PM Josh Poimboeuf <jpoimboe@xxxxxxxxxx> wrote:
> >
> > When a section is empty (e.g. only zero-length alternative
> > replacements), there are no symbols to convert a section symbol
> > reference to.  Skip the reloc instead of erroring out.
> >
> > Fixes: dd590d4d57eb ("objtool/klp: Introduce klp diff subcommand for diffing object files")
> > Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> 
> Acked-by: Song Liu <song@xxxxxxxxxx>
> 
> With a nitpick below:
> 
> [...]
> 
> > @@ -1293,12 +1301,15 @@ static int clone_sym_relocs(struct elfs *e, struct symbol *patched_sym)
> >                     !strcmp(patched_reloc->sym->sec->name, ".altinstr_aux"))
> >                         continue;
> >
> > -               if (convert_reloc_sym(e->patched, patched_reloc)) {
> > +               ret = convert_reloc_sym(e->patched, patched_reloc);
> > +               if (ret < 0) {
> >                         ERROR_FUNC(patched_rsec->base, reloc_offset(patched_reloc),
> >                                    "failed to convert reloc sym '%s' to its proper format",
> >                                    patched_reloc->sym->name);
> >                         return -1;
> >                 }
> > +               if (ret > 0)
> > +                       continue;
> 
> Functions that return -1, 0, 1 are usually more confusing. Shall we add more
> comments for convert_reloc_sym()?

Indeed, thanks.

-- 
Josh