Re: [PATCH bpf-next v4 6/6] selftest/bpf: Fix error usage of ASSERT_OK in xdp_adjust_tail.c

[Xu Kuohai]

On 10/13/2022 7:26 AM, Martin KaFai Lau wrote:
> On 10/11/22 5:01 AM, Xu Kuohai wrote:
> > From: Xu Kuohai <xukuohai@xxxxxxxxxx>
> >
> > xdp_adjust_tail.c calls ASSERT_OK() to check the return value of
> > bpf_prog_test_load(), but the condition is not correct. Fix it.
> >
> > Fixes: 791cad025051 ("bpf: selftests: Get rid of CHECK macro in xdp_adjust_tail.c")
> > Signed-off-by: Xu Kuohai <xukuohai@xxxxxxxxxx>
> > ---
> >   tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c | 6 +++---
> >   1 file changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> > index 009ee37607df..39973ea1ce43 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/xdp_adjust_tail.c
> > @@ -18,7 +18,7 @@ static void test_xdp_adjust_tail_shrink(void)
> >       );
> >       err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
> > -    if (ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
> > +    if (!ASSERT_OK(err, "test_xdp_adjust_tail_shrink"))
> >           return;
> >       err = bpf_prog_test_run_opts(prog_fd, &topts);
> > @@ -53,7 +53,7 @@ static void test_xdp_adjust_tail_grow(void)
> >       );
> >       err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
> > -    if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
> > +    if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
>
> Ouch... ic.  It is why this test has been passing.

Well, it's because the value of err is zero, so ASSERT_OK passed.

> >           return;
> >       err = bpf_prog_test_run_opts(prog_fd, &topts);
> > @@ -90,7 +90,7 @@ static void test_xdp_adjust_tail_grow2(void)
> >       );
> >       err = bpf_prog_test_load(file, BPF_PROG_TYPE_XDP, &obj, &prog_fd);
> > -    if (ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
> > +    if (!ASSERT_OK(err, "test_xdp_adjust_tail_grow"))
> >           return;
> >       /* Test case-64 */
>
> .