Re: [PATCHv2 bpf-next 7/9] selftests/bpf: Add uprobe session cookie test

[Andrii Nakryiko]

On Mon, Jul 1, 2024 at 9:43 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding uprobe session test that verifies the cookie value
> get properly propagated from entry to return program.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
>  .../bpf/prog_tests/uprobe_multi_test.c        | 31 ++++++++++++
>  .../bpf/progs/uprobe_multi_session_cookie.c   | 48 +++++++++++++++++++
>  2 files changed, 79 insertions(+)
>  create mode 100644 tools/testing/selftests/bpf/progs/uprobe_multi_session_cookie.c
>

LGTM

Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>


> diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
> index cd9581f46c73..d5f78fc61013 100644
> --- a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
> +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
> @@ -7,6 +7,7 @@
>  #include "uprobe_multi_bench.skel.h"
>  #include "uprobe_multi_usdt.skel.h"
>  #include "uprobe_multi_session.skel.h"
> +#include "uprobe_multi_session_cookie.skel.h"
>  #include "bpf/libbpf_internal.h"
>  #include "testing_helpers.h"
>  #include "../sdt.h"
> @@ -655,6 +656,34 @@ static void test_session_skel_api(void)
>         uprobe_multi_session__destroy(skel);
>  }
>
> +static void test_session_cookie_skel_api(void)
> +{
> +       struct uprobe_multi_session_cookie *skel = NULL;
> +       int err;
> +
> +       skel = uprobe_multi_session_cookie__open_and_load();
> +       if (!ASSERT_OK_PTR(skel, "fentry_raw_skel_load"))
> +               goto cleanup;
> +
> +       skel->bss->pid = getpid();
> +
> +       err = uprobe_multi_session_cookie__attach(skel);
> +       if (!ASSERT_OK(err, " kprobe_multi_session__attach"))
> +               goto cleanup;
> +
> +       /* trigger all probes */
> +       uprobe_multi_func_1();
> +       uprobe_multi_func_2();
> +       uprobe_multi_func_3();
> +
> +       ASSERT_EQ(skel->bss->test_uprobe_1_result, 1, "test_uprobe_1_result");
> +       ASSERT_EQ(skel->bss->test_uprobe_2_result, 2, "test_uprobe_2_result");
> +       ASSERT_EQ(skel->bss->test_uprobe_3_result, 3, "test_uprobe_3_result");
> +
> +cleanup:
> +       uprobe_multi_session_cookie__destroy(skel);
> +}
> +
>  static void test_bench_attach_uprobe(void)
>  {
>         long attach_start_ns = 0, attach_end_ns = 0;
> @@ -745,4 +774,6 @@ void test_uprobe_multi_test(void)
>                 test_attach_api_fails();
>         if (test__start_subtest("session"))
>                 test_session_skel_api();
> +       if (test__start_subtest("session_cookie"))
> +               test_session_cookie_skel_api();
>  }
> diff --git a/tools/testing/selftests/bpf/progs/uprobe_multi_session_cookie.c b/tools/testing/selftests/bpf/progs/uprobe_multi_session_cookie.c
> new file mode 100644
> index 000000000000..5befdf944dc6
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/uprobe_multi_session_cookie.c
> @@ -0,0 +1,48 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +#include <stdbool.h>
> +#include "bpf_kfuncs.h"
> +
> +char _license[] SEC("license") = "GPL";
> +
> +int pid = 0;
> +
> +__u64 test_uprobe_1_result = 0;
> +__u64 test_uprobe_2_result = 0;
> +__u64 test_uprobe_3_result = 0;
> +
> +static int check_cookie(__u64 val, __u64 *result)
> +{
> +       __u64 *cookie;
> +
> +       if (bpf_get_current_pid_tgid() >> 32 != pid)
> +               return 1;
> +
> +       cookie = bpf_session_cookie();
> +
> +       if (bpf_session_is_return())
> +               *result = *cookie == val ? val : 0;
> +       else
> +               *cookie = val;
> +       return 0;
> +}
> +
> +SEC("uprobe.session//proc/self/exe:uprobe_multi_func_1")
> +int uprobe_1(struct pt_regs *ctx)
> +{
> +       return check_cookie(1, &test_uprobe_1_result);
> +}
> +
> +SEC("uprobe.session//proc/self/exe:uprobe_multi_func_2")
> +int uprobe_2(struct pt_regs *ctx)
> +{
> +       return check_cookie(2, &test_uprobe_2_result);
> +}
> +
> +SEC("uprobe.session//proc/self/exe:uprobe_multi_func_3")
> +int uprobe_3(struct pt_regs *ctx)
> +{
> +       return check_cookie(3, &test_uprobe_3_result);
> +}
> --
> 2.45.2
>