objtool: Ignore empty alternatives

[ Upstream commit 7170cf47d16f1ba29eca07fd818870b7af0a93a5 ]

The .alternatives section can contain entries with no original
instructions. Objtool will currently crash when handling such an entry.

Just skip that entry, but still give a warning to discourage useless
entries.

Signed-off-by: Julien Thierry <[email protected]>
Acked-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Miroslav Benes <[email protected]>
Signed-off-by: Josh Poimboeuf <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
This commit is contained in:
Julien Thierry 2020-03-27 15:28:41 +00:00 • committed by Greg Kroah-Hartman
commit 07d45406db

View file

@ -865,6 +865,12 @@ static int add_special_section_alts(struct objtool_file *file)
}
if (special_alt->group) {
if (!special_alt->orig_len) {
WARN_FUNC("empty alternative entry",
orig_insn->sec, orig_insn->offset);
continue;
}
ret = handle_group_alt(file, special_alt, orig_insn,
&new_insn);
if (ret)