Re: [PATCH bpf-next v4 3/3] selftests/bpf: add testcase for FENTRY/FEXIT with 6+ arguments

[Menglong Dong]

On Sat, Jun 10, 2023 at 11:29 AM Yonghong Song <yhs@xxxxxxxx> wrote:
>
>
>
> On 6/9/23 2:56 AM, menglong8.dong@xxxxxxxxx wrote:
> > From: Menglong Dong <imagedong@xxxxxxxxxxx>
> >
> > Add test9/test10 in fexit_test.c and fentry_test.c to test the fentry
> > and fexit whose target function have 7/12 arguments.
> >
> > Correspondingly, add bpf_testmod_fentry_test7() and
> > bpf_testmod_fentry_test12() to bpf_testmod.c
> >
> > And the testcases passed:
> >
> > ./test_progs -t fexit
> > Summary: 5/12 PASSED, 0 SKIPPED, 0 FAILED
> >
> > ./test_progs -t fentry
> > Summary: 3/0 PASSED, 0 SKIPPED, 0 FAILED
> >
> > Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
> > ---
> > v4:
> > - use different type for args in bpf_testmod_fentry_test{7,12}
> > - add testcase for grabage values in ctx
> > v3:
> > - move bpf_fentry_test{7,12} to bpf_testmod.c and rename them to
> >    bpf_testmod_fentry_test{7,12} meanwhile
> > - get return value by bpf_get_func_ret() in
> >    "fexit/bpf_testmod_fentry_test12", as we don't change ___bpf_ctx_cast()
> >    in this version
> > ---
> >   .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 19 ++++++-
> >   .../selftests/bpf/prog_tests/fentry_fexit.c   |  4 +-
> >   .../selftests/bpf/prog_tests/fentry_test.c    |  2 +
> >   .../selftests/bpf/prog_tests/fexit_test.c     |  2 +
> >   .../testing/selftests/bpf/progs/fentry_test.c | 33 +++++++++++
> >   .../testing/selftests/bpf/progs/fexit_test.c  | 57 +++++++++++++++++++
> >   6 files changed, 115 insertions(+), 2 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> > index cf216041876c..66615fdbe3df 100644
> > --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> > +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> > @@ -191,6 +191,19 @@ noinline int bpf_testmod_fentry_test3(char a, int b, u64 c)
> >       return a + b + c;
> >   }
> >
> > +noinline int bpf_testmod_fentry_test7(u64 a, void *b, short c, int d,
> > +                                   void *e, u64 f, u64 g)
> > +{
> > +     return a + (long)b + c + d + (long)e + f + g;
> > +}
> > +
> > +noinline int bpf_testmod_fentry_test12(u64 a, void *b, short c, int d,
> > +                                    void *e, u64 f, u64 g, u64 h,
> > +                                    u64 i, u64 j, u64 k, u64 l)
> > +{
> > +     return a + (long)b + c + d + (long)e + f + g + h + i + j + k + l;
> > +}
>
> It would be great to add a couple cases with struct arguments
> where each struct has 8 < struct_size <= 16.

Good idea. And I'll add extra test cases for the case
you mentioned before.

> >   __diag_pop();
> >
> >   int bpf_testmod_fentry_ok;
> > @@ -245,7 +258,11 @@ bpf_testmod_test_read(struct file *file, struct kobject *kobj,
> >
> >       if (bpf_testmod_fentry_test1(1) != 2 ||
> >           bpf_testmod_fentry_test2(2, 3) != 5 ||
> > -         bpf_testmod_fentry_test3(4, 5, 6) != 15)
> > +         bpf_testmod_fentry_test3(4, 5, 6) != 15 ||
> > +         bpf_testmod_fentry_test7(16, (void *)17, 18, 19, (void *)20,
> > +                                  21, 22) != 133 ||
> > +         bpf_testmod_fentry_test12(16, (void *)17, 18, 19, (void *)20,
> > +                                   21, 22, 23, 24, 25, 26, 27) != 258)
> >               goto out;
> >
> >       bpf_testmod_fentry_ok = 1;
> [...]
> > diff --git a/tools/testing/selftests/bpf/progs/fexit_test.c b/tools/testing/selftests/bpf/progs/fexit_test.c
> > index 8f1ccb7302e1..a6d8e03ff5b7 100644
> > --- a/tools/testing/selftests/bpf/progs/fexit_test.c
> > +++ b/tools/testing/selftests/bpf/progs/fexit_test.c
> > @@ -78,3 +78,60 @@ int BPF_PROG(test8, struct bpf_fentry_test_t *arg)
> >               test8_result = 1;
> >       return 0;
> >   }
> > +
> > +__u64 test9_result = 0;
> > +SEC("fexit/bpf_testmod_fentry_test7")
> > +int BPF_PROG(test9, __u64 a, void *b, short c, int d, void *e, char f,
> > +          int g, int ret)
> > +{
> > +     test9_result = a == 16 && b == (void *)17 && c == 18 && d == 19 &&
> > +             e == (void *)20 && f == 21 && g == 22 && ret == 133;
> > +     return 0;
> > +}
> > +
> > +__u64 test10_result = 0;
> > +SEC("fexit/bpf_testmod_fentry_test12")
> > +int BPF_PROG(test10, __u64 a, void *b, short c, int d, void *e, char f,
> > +          int g, unsigned int h, long i, __u64 j, unsigned long k,
> > +          unsigned char l)
> > +{
> > +     __u64 ret;
> > +     int err;
> > +
> > +     /* BPF_PROG() don't support 14 arguments, and ctx[12] can't be
> > +      * accessed yet. So we get the return value by bpf_get_func_ret()
> > +      * for now.
> > +      */
> > +     err = bpf_get_func_ret(ctx, &ret);
>
> Maybe just have 11 arguments for this test case?
>
> > +     if (err)
> > +             return 0;
> > +
> > +     test10_result = a == 16 && b == (void *)17 && c == 18 && d == 19 &&
> > +             e == (void *)20 && f == 21 && g == 22 && h == 23 &&
> > +             i == 24 && j == 25 && k == 26 && l == 27 &&
> > +             (int)ret == 258;
> > +     return 0;
> > +}
> > +
> > +__u64 test11_result = 0;
> > +SEC("fexit/bpf_testmod_fentry_test12")
> > +int BPF_PROG(test11, __u64 a, __u64 b, __u64 c, __u64 d, __u64 e, __u64 f,
> > +          __u64 g, __u64 h, __u64 i, __u64 j, __u64 k, __u64 l)
> > +{
> > +     __u64 ret;
> > +     int err;
> > +
> > +     /* BPF_PROG() don't support 14 arguments, and ctx[12] can't be
> > +      * accessed yet. So we get the return value by bpf_get_func_ret()
> > +      * for now.
> > +      */
> > +     err = bpf_get_func_ret(ctx, &ret);
> > +     if (err)
> > +             return 0;
> > +
> > +     test11_result = a == 16 && b == 17 && c == 18 && d == 19 &&
> > +             e == 20 && f == 21 && g == 22 && h == 23 &&
> > +             i == 24 && j == 25 && k == 26 && l == 27 &&
> > +             ret == 258;
> > +     return 0;
> > +}