Re: [PATCH bpf] bpf: reject ERR_PTR map->record in map_check_btf

[sun jian]

On Thu, Apr 16, 2026 at 11:42 PM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> On Thu Apr 16, 2026 at 7:48 AM PDT, Sun Jian wrote:
> > btf_parse_fields() returns an ERR_PTR() when it encounters an invalid
> > special field in map value BTF.
> >
> > For example, an invalid kptr-annotated field whose tagged pointee is not
> > a full struct type can make btf_parse_fields() fail with -EINVAL.
> >
> > map_check_btf() stores the result in map->record, but currently only
> > handles the successful non-NULL case explicitly. ERR_PTR() results are
> > not rejected immediately before proceeding with the rest of map BTF
> > setup.
>
> yes. So ?
>
> > Handle IS_ERR(map->record) explicitly in map_check_btf() and return the
> > underlying error code immediately.
>
> why ?
>
> pw-bot: cr

Thanks for the feedback.

What I can show is only that an invalid map value BTF record is carried
past map_check_btf() on the old code, instead of being rejected there.

I couldn't demonstrate a stronger observable bad outcome beyond that, so I'll
drop this patch.