Re: [PATCH v1 bpf-next 1/8] selftest: bpf: Use BPF_SOCK_OPS_ALL_CB_FLAGS + 1 for bad_cb_test_rv.

On Fri, May 8, 2026 at 12:02 PM <[email protected]> wrote:
>
> Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
> - [Medium] Using `BPF_SOCK_OPS_ALL_CB_FLAGS + 1` to test invalid BPF callback flags creates brittle test logic that assumes contiguous bitmasks and breaks forward compatibility.
> --
>
> commit dfed6c2387074d0f6f7afb70b6bba777371f7267
> Author: Kuniyuki Iwashima <[email protected]>
>
> selftest: bpf: Use BPF_SOCK_OPS_ALL_CB_FLAGS + 1 for bad_cb_test_rv.
>
> Once bpf_sock_ops_cb_flags_set() supports a new flag,
> tcpbpf_user.c fails due to the hard-coded max value, 0x80.
>
> > diff --git a/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c b/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c
> > index 7e8fe1bad03f5..e4849d2a2956f 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/tcpbpf_user.c
> > @@ -26,7 +26,8 @@ static void verify_result(struct tcpbpf_globals *result)
> >       ASSERT_EQ(result->bytes_acked, 1002, "bytes_acked");
> >       ASSERT_EQ(result->data_segs_in, 1, "data_segs_in");
> >       ASSERT_EQ(result->data_segs_out, 1, "data_segs_out");
> > -     ASSERT_EQ(result->bad_cb_test_rv, 0x80, "bad_cb_test_rv");
> > +     ASSERT_EQ(result->bad_cb_test_rv, BPF_SOCK_OPS_ALL_CB_FLAGS + 1,
> > +               "bad_cb_test_rv");
>
> Is BPF_SOCK_OPS_ALL_CB_FLAGS + 1 robust for forward compatibility?

This test is not supposed to run on older kernel.