On Mon, Sep 20, 2021 at 4:18 PM Andrii Nakryiko <andrii@xxxxxxxxxx> wrote:
>
> Make sure to not use ref_ctr_off feature when running on old kernels
> that don't support this feature. This allows to test libbpf's legacy
> kprobe and uprobe logic on old kernels.
>
> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> ---
> .../selftests/bpf/prog_tests/attach_probe.c | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> index bf307bb9e446..cbd6b6175d5c 100644
> --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> @@ -14,6 +14,12 @@ void test_attach_probe(void)
> struct test_attach_probe* skel;
> size_t uprobe_offset;
> ssize_t base_addr, ref_ctr_offset;
> + bool legacy;
> +
> + /* check is new-style kprobe/uprobe API is supported */
> + legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0;
> +
> + legacy = true;
What is the idea of the above?
One of them is a leftover?
