On Tue, 10 Mar 2026, Josh Poimboeuf wrote:
> On Tue, Mar 10, 2026 at 11:47:41AM +0100, Miroslav Benes wrote:
> > Hi,
> >
> > > @@ -3691,9 +3691,30 @@ static void checksum_update_insn(struct
> > > objtool_file *file, struct symbol *func,
> > > struct instruction *insn)
> > > {
> > > struct reloc *reloc = insn_reloc(file, insn);
> > > + struct alternative *alt;
> > > unsigned long offset;
> > > struct symbol *sym;
> > >
> > > + for (alt = insn->alts; alt; alt = alt->next) {
> > > + struct alt_group *alt_group = alt->insn->alt_group;
> > > +
> > > + checksum_update(func, insn, &alt->type, sizeof(alt->type));
> > > +
> > > + if (alt_group && alt_group->orig_group) {
> > > + struct instruction *alt_insn;
> > > +
> > > + checksum_update(func, insn, &alt_group->feature,
> > > sizeof(alt_group->feature));
> > > +
> > > + for (alt_insn = alt->insn; alt_insn; alt_insn =
> > > next_insn_same_sec(file, alt_insn)) {
> > > + checksum_update_insn(file, func, alt_insn);
> > > + if (alt_insn == alt_group->last_insn)
> > > + break;
> > > + }
> > > + } else {
> > > + checksum_update(func, insn, &alt->insn->offset,
> > > sizeof(alt->insn->offset));
> > > + }
> > > + }
> > > +
> >
> > does this hunk belong to the patch? Unless I am missing something, it
> > might be worth a separate one.
>
> It belongs, but I should have clarified that in the patch description.
>
> This hunk wasn't needed before because validate_branch() already
> iterates all the alternatives, so it was calling checksum_update_insn()
> for every instruction in the function, including the alternatives.
>
> Now that it's no longer called by validate_branch(),
> checksum_update_insn() has to manually iterate the alternatives.
After writing the email I had a suspicion it must have been something like
above but failed to find it. Now I see that next_insn_to_validate() called
in do_validate_branch() handles exactly that. Thanks for the pointer. The
patch looks good to me then (and the rest as well as far as I can judge).
I must admit that objtool has gotten so complex that I have a hard time to
track everything in the code :).
Regards
Miroslav
