On Wed, Feb 8, 2023 at 12:57 PM Ilya Leoshkevich <iii@xxxxxxxxxxxxx> wrote:
>
> eBPF selftests produce a few false positives with MSan. These can be
> divided in two classes:
>
> - Sending uninitalized data via a socket.
> - bpf_obj_get_info_by_fd() calls.
>
> The first class is trivial; the second should ideally be handled by
> libbpf, but it doesn't look possible at the moment, since we don't
> know the type of the eBPF object referred to by fd, and therefore the
> structure of the output data.
yeah, bpf_obj_get_info_by_fd() is quite bad from usability standpoint.
I think we should add bpf_get_{map,prog,link,btf}_info_by_fd()
wrappers and try to use them. That will allow to specify correct
expected struct types, we'll be able to mark initialized memory
properly. We already have bpf_{map,prog,btf,link}_get_fd_by_id()
family, so having similar for getting info seems fitting (even if
underlying bpf() command is generic).
Thoughts?
>
> Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
> ---
> tools/testing/selftests/bpf/cap_helpers.c | 3 +++
> tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c | 10 ++++++++++
> tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c | 3 +++
> tools/testing/selftests/bpf/prog_tests/btf.c | 11 +++++++++++
> tools/testing/selftests/bpf/prog_tests/send_signal.c | 2 ++
> .../selftests/bpf/prog_tests/tp_attach_query.c | 6 ++++++
> tools/testing/selftests/bpf/prog_tests/xdp_bonding.c | 3 +++
> tools/testing/selftests/bpf/xdp_synproxy.c | 2 ++
> 8 files changed, 40 insertions(+)
>
[...]
