Re: [PATCH bpf-next v3 3/3] selftests/bpf: add test for legacy/perf kprobe/uprobe attach mode

[Andrii Nakryiko]

On Mon, Feb 20, 2023 at 6:54 PM <menglong8.dong@xxxxxxxxx> wrote:
>
> From: Menglong Dong <imagedong@xxxxxxxxxxx>
>
> Add the testing for kprobe/uprobe attaching in default, legacy, perf and
> link mode. And the testing passed:
>
> ./test_progs -t attach_probe
> $5/1     attach_probe/manual-default:OK
> $5/2     attach_probe/manual-legacy:OK
> $5/3     attach_probe/manual-perf:OK
> $5/4     attach_probe/manual-link:OK
> $5/5     attach_probe/auto:OK
> $5/6     attach_probe/kprobe-sleepable:OK
> $5/7     attach_probe/uprobe-lib:OK
> $5/8     attach_probe/uprobe-sleepable:OK
> $5/9     attach_probe/uprobe-ref_ctr:OK
> $5       attach_probe:OK
> Summary: 1/9 PASSED, 0 SKIPPED, 0 FAILED
>
> Reviewed-by: Biao Jiang <benbjiang@xxxxxxxxxxx>
> Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
> Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
> ---
>  .../selftests/bpf/prog_tests/attach_probe.c   | 54 ++++++++++++++-----
>  .../selftests/bpf/progs/test_attach_probe.c   | 32 -----------
>  .../bpf/progs/test_attach_probe_manual.c      | 53 ++++++++++++++++++
>  3 files changed, 93 insertions(+), 46 deletions(-)
>  create mode 100644 tools/testing/selftests/bpf/progs/test_attach_probe_manual.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> index 8afd3e6066b8..e71cb44bf2e7 100644
> --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> @@ -1,6 +1,7 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #include <test_progs.h>
>  #include "test_attach_kprobe_sleepable.skel.h"
> +#include "test_attach_probe_manual.skel.h"
>  #include "test_attach_probe.skel.h"
>
>  /* this is how USDT semaphore is actually defined, except volatile modifier */
> @@ -33,33 +34,48 @@ static noinline void trigger_func4(void)
>  static char test_data[] = "test_data";
>
>  /* manual attach kprobe/kretprobe/uprobe/uretprobe testings */
> -static void test_attach_probe_manual(struct test_attach_probe *skel)
> +static void test_attach_probe_manual(enum probe_attach_mode attach_mode)
>  {
>         DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
> +       DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, kprobe_opts);
>         struct bpf_link *kprobe_link, *kretprobe_link;
>         struct bpf_link *uprobe_link, *uretprobe_link;
> +       struct test_attach_probe_manual *skel;
>         ssize_t uprobe_offset;
>
> +       skel = test_attach_probe_manual__open();
> +       if (!ASSERT_OK_PTR(skel, "skel_kprobe_manual_open"))
> +               return;
> +
> +       if (!ASSERT_OK(test_attach_probe_manual__load(skel), "skel_manual_load"))
> +               goto cleanup;

use test_attach_probe_manual__open_and_load() ?

> +       if (!ASSERT_OK_PTR(skel->bss, "manual_check_bss"))
> +               goto cleanup;
> +

no need to test this, lots of other tests validate this already, BPF
skeleton has been validated many times over, no need to add this in
new tests

>         uprobe_offset = get_uprobe_offset(&trigger_func);
>         if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset"))
> -               return;
> +               goto cleanup;

didn't you update all the `goto cleanup;` into `return;` in previous
patch, and now updating it back to `goto cleanup;`? Maybe just keep an
empty `cleanup:` label at the end to reduce churn?

>
>         /* manual-attach kprobe/kretprobe */
> -       kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe,
> -                                                false /* retprobe */,
> -                                                SYS_NANOSLEEP_KPROBE_NAME);
> +       kprobe_opts.attach_mode = attach_mode;
> +       kprobe_opts.retprobe = false;
> +       kprobe_link = bpf_program__attach_kprobe_opts(skel->progs.handle_kprobe,
> +                                                     SYS_NANOSLEEP_KPROBE_NAME,
> +                                                     &kprobe_opts);
>         if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe"))
> -               return;
> +               goto cleanup;
>         skel->links.handle_kprobe = kprobe_link;
>
> -       kretprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kretprobe,
> -                                                   true /* retprobe */,
> -                                                   SYS_NANOSLEEP_KPROBE_NAME);
> +       kprobe_opts.retprobe = true;
> +       kretprobe_link = bpf_program__attach_kprobe_opts(skel->progs.handle_kretprobe,
> +                                                        SYS_NANOSLEEP_KPROBE_NAME,
> +                                                        &kprobe_opts);
>         if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe"))
> -               return;
> +               goto cleanup;
>         skel->links.handle_kretprobe = kretprobe_link;
>
>         /* manual-attach uprobe/uretprobe */
> +       uprobe_opts.attach_mode = attach_mode;
>         uprobe_opts.ref_ctr_offset = 0;
>         uprobe_opts.retprobe = false;
>         uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe,

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