On Sat, Jul 16, 2022 at 6:34 AM Yonghong Song [off-list ref] wrote:

On 7/12/22 7:58 AM, Benjamin Tissoires wrote:

quoted

We add 2 new kfuncs that are following the RET_PTR_TO_MEM
capability from the previous commit.
Then we test them in selftests:
the first tests are testing valid case, and are not failing,
and the later ones are actually preventing the program to be loaded
because they are wrong.

To work around that, we mark the failing ones as not autoloaded
(with SEC("?tc")), and we manually enable them one by one, ensuring
the verifier rejects them.

To be able to use bpf_program__set_autoload() from libbpf, we need
to use a plain skeleton, not a light-skeleton, and this is why we
also change the Makefile to generate both for kfunc_call_test.c

Signed-off-by: Benjamin Tissoires <redacted>

---

new in v6
---
  include/linux/btf.h                           |  4 +-
  net/bpf/test_run.c                            | 22 +++++
  tools/testing/selftests/bpf/Makefile          |  5 +-
  .../selftests/bpf/prog_tests/kfunc_call.c     | 48 ++++++++++
  .../selftests/bpf/progs/kfunc_call_test.c     | 89 +++++++++++++++++++
  5 files changed, 165 insertions(+), 3 deletions(-)

diff --git a/include/linux/btf.h b/include/linux/btf.h
index 31da4273c2ec..6f46ff2128ae 100644
--- a/include/linux/btf.h
+++ b/include/linux/btf.h

@@ -422,7 +422,9 @@ static inline int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dt

  static inline bool btf_type_is_struct_ptr(struct btf *btf, const struct btf_type *t)
  {
-     /* t comes in already as a pointer */
+     if (!btf_type_is_ptr(t))
+             return false;

Why we have a change here?

Definitely a mistake while fixing/rebasing the series.

Will bring this hunk in the previous patch in the next revision.

Thanks for the review!

Cheers,
Benjamin

quoted

+
      t = btf_type_by_id(btf, t->type);

      /* allow const */

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 9da2a42811e8..0b4026ea4652 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c

@@ -606,6 +606,24 @@ noinline void bpf_kfunc_call_memb1_release(struct prog_test_member1 *p)
      WARN_ON_ONCE(1);
  }

+static int *__bpf_kfunc_call_test_get_mem(struct prog_test_ref_kfunc *p, const int size)
+{
+     if (size > 2 * sizeof(int))
+             return NULL;
+
+     return (int *)p;
+}
+
+noinline int *bpf_kfunc_call_test_get_rdwr_mem(struct prog_test_ref_kfunc *p, const int rdwr_buf_size)
+{
+     return __bpf_kfunc_call_test_get_mem(p, rdwr_buf_size);
+}
+
+noinline int *bpf_kfunc_call_test_get_rdonly_mem(struct prog_test_ref_kfunc *p, const int rdonly_buf_size)
+{
+     return __bpf_kfunc_call_test_get_mem(p, rdonly_buf_size);
+}
+
  noinline struct prog_test_ref_kfunc *
  bpf_kfunc_call_test_kptr_get(struct prog_test_ref_kfunc **pp, int a, int b)
  {

@@ -704,6 +722,8 @@ BTF_ID(func, bpf_kfunc_call_memb_acquire)
  BTF_ID(func, bpf_kfunc_call_test_release)
  BTF_ID(func, bpf_kfunc_call_memb_release)
  BTF_ID(func, bpf_kfunc_call_memb1_release)
+BTF_ID(func, bpf_kfunc_call_test_get_rdwr_mem)
+BTF_ID(func, bpf_kfunc_call_test_get_rdonly_mem)
  BTF_ID(func, bpf_kfunc_call_test_kptr_get)
  BTF_ID(func, bpf_kfunc_call_test_pass_ctx)
  BTF_ID(func, bpf_kfunc_call_test_pass1)

@@ -731,6 +751,8 @@ BTF_SET_END(test_sk_release_kfunc_ids)
  BTF_SET_START(test_sk_ret_null_kfunc_ids)
  BTF_ID(func, bpf_kfunc_call_test_acquire)
  BTF_ID(func, bpf_kfunc_call_memb_acquire)
+BTF_ID(func, bpf_kfunc_call_test_get_rdwr_mem)
+BTF_ID(func, bpf_kfunc_call_test_get_rdonly_mem)
  BTF_ID(func, bpf_kfunc_call_test_kptr_get)
  BTF_SET_END(test_sk_ret_null_kfunc_ids)

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