Re: [RFC v5 04/57] objtool: check: Ignore empty alternative groups

[Josh Poimboeuf]

On Thu, Jan 09, 2020 at 04:02:07PM +0000, Julien Thierry wrote:
> Atlernative section can contain entries for alternatives with no
> 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 <jthierry@xxxxxxxxxx>
> ---
>  tools/objtool/check.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> index 5968e6f08891..27e5380e0e0b 100644
> --- a/tools/objtool/check.c
> +++ b/tools/objtool/check.c
> @@ -866,6 +866,13 @@ static int add_special_section_alts(struct objtool_file *file)
>  		}
>  
>  		if (special_alt->group) {
> +			if (!special_alt->orig_len) {
> +				WARN("empty alternative entry at %s+0x%lx",
> +				     orig_insn->sec->name,
> +				     orig_insn->offset);
> +				continue;
> +			}
> +

I think WARN_FUNC() can be used here instead.

-- 
Josh