Re: [PATCHv2 bpf-next 2/5] selftests/bpf: Add re-attach test to fentry_test

[Jiri Olsa <jolsa@redhat.com>]

On Wed, Apr 07, 2021 at 03:47:30PM -0700, Andrii Nakryiko wrote:
> On Wed, Apr 7, 2021 at 4:21 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > Adding the test to re-attach (detach/attach again) tracing
> > fentry programs, plus check that already linked program can't
> > be attached again.
> >
> > Fixing the number of check-ed results, which should be 8.
> >
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >  .../selftests/bpf/prog_tests/fentry_test.c    | 48 +++++++++++++++----
> >  1 file changed, 38 insertions(+), 10 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/fentry_test.c b/tools/testing/selftests/bpf/prog_tests/fentry_test.c
> > index 04ebbf1cb390..1f7566e772e9 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/fentry_test.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/fentry_test.c
> > @@ -3,20 +3,24 @@
> >  #include <test_progs.h>
> >  #include "fentry_test.skel.h"
> >
> > -void test_fentry_test(void)
> > +static __u32 duration;
> > +
> > +static int fentry_test(struct fentry_test *fentry_skel)
> >  {
> > -       struct fentry_test *fentry_skel = NULL;
> > +       struct bpf_link *link;
> >         int err, prog_fd, i;
> > -       __u32 duration = 0, retval;
> >         __u64 *result;
> > -
> > -       fentry_skel = fentry_test__open_and_load();
> > -       if (CHECK(!fentry_skel, "fentry_skel_load", "fentry skeleton failed\n"))
> > -               goto cleanup;
> > +       __u32 retval;
> >
> >         err = fentry_test__attach(fentry_skel);
> >         if (CHECK(err, "fentry_attach", "fentry attach failed: %d\n", err))
> > -               goto cleanup;
> > +               return err;
> > +
> > +       /* Check that already linked program can't be attached again. */
> > +       link = bpf_program__attach(fentry_skel->progs.test1);
> > +       if (CHECK(!IS_ERR(link), "fentry_attach_link",
> 
> if (!ASSERT_ERR_PTR(link, "fentry_attach_link")) ?

ok

> 
> > +                 "re-attach without detach should not succeed"))
> > +               return -1;
> >
> >         prog_fd = bpf_program__fd(fentry_skel->progs.test1);
> >         err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
> > @@ -26,12 +30,36 @@ void test_fentry_test(void)
> >               err, errno, retval, duration);
> >
> >         result = (__u64 *)fentry_skel->bss;
> > -       for (i = 0; i < 6; i++) {
> > +       for (i = 0; i < 8; i++) {
> 
> how about using sizeof(*fentry_skel->bss) / sizeof(__u64) ?

ok

> 
> >                 if (CHECK(result[i] != 1, "result",
> >                           "fentry_test%d failed err %lld\n", i + 1, result[i]))
> > -                       goto cleanup;
> > +                       return -1;
> >         }
> >
> > +       fentry_test__detach(fentry_skel);
> > +
> > +       /* zero results for re-attach test */
> > +       for (i = 0; i < 8; i++)
> > +               result[i] = 0;
> > +       return 0;
> > +}
> > +
> > +void test_fentry_test(void)
> > +{
> > +       struct fentry_test *fentry_skel = NULL;
> > +       int err;
> > +
> > +       fentry_skel = fentry_test__open_and_load();
> > +       if (CHECK(!fentry_skel, "fentry_skel_load", "fentry skeleton failed\n"))
> > +               goto cleanup;
> > +
> > +       err = fentry_test(fentry_skel);
> > +       if (CHECK(err, "fentry_test", "first attach failed\n"))
> > +               goto cleanup;
> > +
> > +       err = fentry_test(fentry_skel);
> > +       CHECK(err, "fentry_test", "second attach failed\n");
> 
> overall: please try to use ASSERT_xxx macros, they are easier to
> follow and require less typing

ok, will check

thanks,
jirka