On Tue, Mar 15, 2022 at 5:44 PM Kui-Feng Lee <kuifeng@xxxxxx> wrote:
>
> Make sure BPF cookies are correct for fentry/fexit/fmod_ret.
>
> Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxx>
> ---
> .../selftests/bpf/prog_tests/bpf_cookie.c | 61 +++++++++++++++++++
> .../selftests/bpf/progs/test_bpf_cookie.c | 24 ++++++++
> 2 files changed, 85 insertions(+)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
> index 0612e79a9281..6d06c5046e9c 100644
> --- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
> +++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
> @@ -237,6 +237,65 @@ static void pe_subtest(struct test_bpf_cookie *skel)
> bpf_link__destroy(link);
> }
>
> +static void tracing_subtest(struct test_bpf_cookie *skel)
> +{
> + __u64 cookie;
> + int prog_fd;
> + int fentry_fd = -1, fexit_fd = -1, fmod_ret_fd = -1;
> + struct bpf_test_run_opts opts;
> +
> + skel->bss->fentry_res = 0;
> + skel->bss->fexit_res = 0;
> +
> + cookie = 0x100000;
> + prog_fd = bpf_program__fd(skel->progs.fentry_test1);
> + if (!ASSERT_GE(prog_fd, 0, "fentry.prog_fd"))
> + return;
this can't return <= 0 if skeleton was loaded, don't bother doing
these checks, they just distract from the main objective of the test
> + fentry_fd = bpf_raw_tracepoint_cookie_open(NULL, prog_fd, cookie);
> + if (!ASSERT_GE(fentry_fd, 0, "fentry.open"))
> + return;
> +
> + cookie = 0x200000;
> + prog_fd = bpf_program__fd(skel->progs.fexit_test1);
> + if (!ASSERT_GE(prog_fd, 0, "fexit.prog_fd"))
> + goto cleanup;
> + fexit_fd = bpf_raw_tracepoint_cookie_open(NULL, prog_fd, cookie);
> + if (!ASSERT_GE(fexit_fd, 0, "fexit.open"))
> + goto cleanup;
> +
> + cookie = 0x300000;
> + prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
> + if (!ASSERT_GE(prog_fd, 0, "fmod_ret.prog_fd"))
> + goto cleanup;
> + fmod_ret_fd = bpf_raw_tracepoint_cookie_open(NULL, prog_fd, cookie);
> + if (!ASSERT_GE(fmod_ret_fd, 0, "fmod_ret.opoen"))
> + goto cleanup;
> +
> + bzero(&opts, sizeof(opts));
> + opts.sz = sizeof(opts);
> + opts.repeat = 1;
We have LIBBPF_OPTS() macro for working with opts, please use that.
But I think in this case NULL for opts will be equivalent. Seems like
kernel just ignores repeat parameter for tracing programs (and for
others repeat == 0 means repeat == 1).
> + prog_fd = bpf_program__fd(skel->progs.fentry_test1);
> + bpf_prog_test_run_opts(prog_fd, &opts);
> +
> + bzero(&opts, sizeof(opts));
> + opts.sz = sizeof(opts);
> + opts.repeat = 1;
> + prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
> + bpf_prog_test_run_opts(prog_fd, &opts);
> +
> + ASSERT_EQ(skel->bss->fentry_res, 0x100000, "fentry_res");
> + ASSERT_EQ(skel->bss->fexit_res, 0x200000, "fexit_res");
> + ASSERT_EQ(skel->bss->fmod_ret_res, 0x300000, "fmod_ret_res");
> +
> +cleanup:
> + if (fentry_fd >= 0)
> + close(fentry_fd);
> + if (fexit_fd >= 0)
> + close(fexit_fd);
> + if (fmod_ret_fd >= 0)
> + close(fmod_ret_fd);
> +}
> +
> void test_bpf_cookie(void)
> {
> struct test_bpf_cookie *skel;
> @@ -255,6 +314,8 @@ void test_bpf_cookie(void)
> tp_subtest(skel);
> if (test__start_subtest("perf_event"))
> pe_subtest(skel);
> + if (test__start_subtest("tracing"))
> + tracing_subtest(skel);
kprobes are also tracing, but this one is specifically about BPF
trampoline-based programs. Let's use "trampoline" here to
disambiguate.
>
> test_bpf_cookie__destroy(skel);
> }
> diff --git a/tools/testing/selftests/bpf/progs/test_bpf_cookie.c b/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
> index 2d3a7710e2ce..a9f83f46e7b7 100644
> --- a/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
> +++ b/tools/testing/selftests/bpf/progs/test_bpf_cookie.c
> @@ -14,6 +14,9 @@ int uprobe_res;
> int uretprobe_res;
> int tp_res;
> int pe_res;
> +int fentry_res;
> +int fexit_res;
> +int fmod_ret_res;
>
> static void update(void *ctx, int *res)
> {
> @@ -82,4 +85,25 @@ int handle_pe(struct pt_regs *ctx)
> return 0;
> }
>
> +SEC("fentry/bpf_fentry_test1")
> +int BPF_PROG(fentry_test1, int a)
> +{
> + update(ctx, &fentry_res);
> + return 0;
> +}
> +
> +SEC("fexit/bpf_fentry_test1")
> +int BPF_PROG(fexit_test1, int a, int ret)
> +{
> + update(ctx, &fexit_res);
> + return 0;
> +}
> +
> +SEC("fmod_ret/bpf_modify_return_test")
> +int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
> +{
> + update(ctx, &fmod_ret_res);
> + return 1234;
> +}
> +
> char _license[] SEC("license") = "GPL";
> --
> 2.30.2
>
