Re: [PATCH bpf-next v3 8/8] selftests/bpf: ringbuf_multi: use runtime page size

[Yauheni Kaliuta <yauheni.kaliuta@redhat.com>]

Hi, Andrii!

On Wed, Mar 31, 2021 at 9:52 PM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Wed, Mar 31, 2021 at 9:45 AM Yauheni Kaliuta
> <yauheni.kaliuta@redhat.com> wrote:
> >
> > Set bpf table sizes dynamically according to the runtime page size
> > value.
> >
> > Do not switch to ASSERT macros, keep CHECK, for consistency with the
> > rest of the test. Can be a separate cleanup patch.
> >
> > Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
> > ---
> >  .../selftests/bpf/prog_tests/ringbuf_multi.c  | 23 ++++++++++++++++---
> >  .../selftests/bpf/progs/test_ringbuf_multi.c  |  1 -
> >  2 files changed, 20 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
> > index d37161e59bb2..159de99621c7 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
> > @@ -41,13 +41,30 @@ static int process_sample(void *ctx, void *data, size_t len)
> >  void test_ringbuf_multi(void)
> >  {
> >         struct test_ringbuf_multi *skel;
> > -       struct ring_buffer *ringbuf;
> > +       struct ring_buffer *ringbuf = NULL;
> >         int err;
> > +       int page_size = getpagesize();
> >
> > -       skel = test_ringbuf_multi__open_and_load();
> > -       if (CHECK(!skel, "skel_open_load", "skeleton open&load failed\n"))
> > +       skel = test_ringbuf_multi__open();
> > +       if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
> >                 return;
> >
> > +       err = bpf_map__set_max_entries(skel->maps.ringbuf1, page_size);
> > +       if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
> > +               goto cleanup;
> > +
> > +       err = bpf_map__set_max_entries(skel->maps.ringbuf2, page_size);
> > +       if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
> > +               goto cleanup;
> > +
> > +       err = bpf_map__set_max_entries(bpf_map__inner_map(skel->maps.ringbuf_arr), page_size);
> > +       if (CHECK(err != 0, "bpf_map__set_max_entries", "bpf_map__set_max_entries failed\n"))
> > +               goto cleanup;
> > +
> > +       err = test_ringbuf_multi__load(skel);
> > +       if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
> > +               goto cleanup;
> > +
>
> To test bpf_map__set_inner_map_fd() interaction with map-in-map
> initialization, can you extend the test to have another map-in-map
> (could be HASHMAP, just for fun), which is initialized with either
> ringbuf1 or ringbuf2, but then from user-space use a different way to
> override inner map definition:
>
> int proto_fd = bpf_create_map(... RINGBUF of page_size ...);
> bpf_map__set_inner_map_fd(skel->maps.ringbuf_hash, proto_fd);
> close(proto_fd);
>
> /* perform load, it should succeed */
>
> Important is to use a different map-in-map from ringbuf_arr, so that
> load fails, unless set_inner_map_fd() properly updates internals of a
> map.

Is that what you mean?
https://github.com/ykaliuta/linux/commit/59fedd3b00678023d04b74bac61581a04896602e

diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
index 159de99621c7..5794317d05dd 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf_multi.c
@@ -44,6 +44,7 @@ void test_ringbuf_multi(void)
        struct ring_buffer *ringbuf = NULL;
        int err;
        int page_size = getpagesize();
+       int proto_fd;

        skel = test_ringbuf_multi__open();
        if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
@@ -61,6 +62,16 @@ void test_ringbuf_multi(void)
        if (CHECK(err != 0, "bpf_map__set_max_entries",
"bpf_map__set_max_entries failed\n"))
                goto cleanup;

+       proto_fd = bpf_create_map(BPF_MAP_TYPE_RINGBUF, 0, 0, page_size, 0);
+       if (CHECK(proto_fd == -1, "bpf_create_map", "bpf_create_map failed\n"))
+               goto cleanup;
+
+       err = bpf_map__set_inner_map_fd(skel->maps.ringbuf_hash, proto_fd);
+       if (CHECK(err != 0, "bpf_map__set_inner_map_fd",
"bpf_map__set_inner_map_fd failed\n"))
+               goto cleanup;
+
+       close(proto_fd);
+
        err = test_ringbuf_multi__load(skel);
        if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
                goto cleanup;
diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
index 055c10b2ff80..197b86546dca 100644
--- a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
@@ -30,6 +30,17 @@ struct {
        },
 };

+struct {
+       __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
+       __uint(max_entries, 1);
+       __type(key, int);
+       __array(values, struct ringbuf_map);
+} ringbuf_hash SEC(".maps") = {
+       .values = {
+               [0] = &ringbuf1,
+       },
+};
+


I get with it:

test_ringbuf_multi:PASS:bpf_map__set_inner_map_fd 0 nsec
libbpf: Error in bpf_create_map_xattr(ringbuf_arr):Invalid
argument(-22). Retrying without BTF.
libbpf: Error in bpf_create_map_xattr(ringbuf_hash):Invalid
argument(-22). Retrying without BTF.
libbpf: map 'ringbuf_hash': failed to create: Invalid argument(-22)
libbpf: failed to load object 'test_ringbuf_multi'
libbpf: failed to load BPF skeleton 'test_ringbuf_multi': -22
test_ringbuf_multi:FAIL:skel_load skeleton load failed
#90 ringbuf_multi:FAIL


>
> >         /* only trigger BPF program for current process */
> >         skel->bss->pid = getpid();
> >
> > diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
> > index edf3b6953533..055c10b2ff80 100644
> > --- a/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
> > +++ b/tools/testing/selftests/bpf/progs/test_ringbuf_multi.c
> > @@ -15,7 +15,6 @@ struct sample {
> >
> >  struct ringbuf_map {
> >         __uint(type, BPF_MAP_TYPE_RINGBUF);
> > -       __uint(max_entries, 1 << 12);
> >  } ringbuf1 SEC(".maps"),
> >    ringbuf2 SEC(".maps");
> >
> > --
> > 2.31.1
> >
>


-- 
WBR, Yauheni