Re: [PATCH bpf-next v4 2/2] selftests/bpf: Cover trusted BTF ID argument provenance

[Amery Hung]

On Wed, Oct 7, 2026 at 9:25 AM Yiyang Chen
<chenyy23@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Extend verifier_global_ptr_args.c with calls that pass bare and
> RCU-protected task pointers to a global __arg_trusted parameter. Both
> calls must be rejected because neither pointer is referenced or trusted.
>
> Add paired test-module kfuncs that return and accept a nullable trusted
> task pointer. Passing the return value directly must succeed, covering
> PTR_TRUSTED | PTR_MAYBE_NULL handling in the common argument checker.
>
> Signed-off-by: Yiyang Chen <chenyy23@xxxxxxxxxxxxxxxxxxxxx>

Reviewed-by: Amery Hung <ameryhung@xxxxxxxxx>

> ---
>  tools/testing/selftests/bpf/progs/iters_testmod.c  | 11 +++++++
>  .../selftests/bpf/progs/verifier_global_ptr_args.c | 35 ++++++++++++++++++++++
>  .../testing/selftests/bpf/test_kmods/bpf_testmod.c | 11 +++++++
>  .../selftests/bpf/test_kmods/bpf_testmod_kfunc.h   |  2 ++
>  4 files changed, 59 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/progs/iters_testmod.c b/tools/testing/selftests/bpf/progs/iters_testmod.c
> index f65cc9766633e..145750bb64ef8 100644
> --- a/tools/testing/selftests/bpf/progs/iters_testmod.c
> +++ b/tools/testing/selftests/bpf/progs/iters_testmod.c
> @@ -46,6 +46,17 @@ int iter_next_trusted_or_null(const void *ctx)
>         return 0;
>  }
>
> +SEC("syscall")
> +__success
> +int trusted_nullable_kfunc(const void *ctx)
> +{
> +       struct task_struct *task;
> +
> +       task = bpf_kfunc_trusted_null_test();
> +       bpf_kfunc_trusted_nullable_test(task);
> +       return 0;
> +}
> +

nit: tools/testing/selftests/bpf/progs/test_kfunc_param_nullable.c
feels like a better place than iters_testmod.c for the test.