On Mon, Apr 22, 2024 at 5:14 AM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Adding kprobe multi session test that verifies the cookie
> value get properly propagated from entry to return program.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
Forgot to update subject (still using "wrapper" naming)
overall LGTM, see nits
Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> tools/testing/selftests/bpf/bpf_kfuncs.h | 1 +
> .../bpf/prog_tests/kprobe_multi_test.c | 35 ++++++++++++
> .../bpf/progs/kprobe_multi_session_cookie.c | 56 +++++++++++++++++++
> 3 files changed, 92 insertions(+)
> create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c
>
> diff --git a/tools/testing/selftests/bpf/bpf_kfuncs.h b/tools/testing/selftests/bpf/bpf_kfuncs.h
> index 180030b5d828..0281921cd654 100644
> --- a/tools/testing/selftests/bpf/bpf_kfuncs.h
> +++ b/tools/testing/selftests/bpf/bpf_kfuncs.h
> @@ -77,4 +77,5 @@ extern int bpf_verify_pkcs7_signature(struct bpf_dynptr *data_ptr,
> struct bpf_key *trusted_keyring) __ksym;
>
> extern bool bpf_session_is_return(void) __ksym;
> +extern __u64 *bpf_session_cookie(void) __ksym;
btw, should we use `long *` as return type to avoid relying on having
__u64 alias be available? Long is always an 8-byte value in the BPF
world, it should be fine.
> #endif
> diff --git a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
> index d1f116665551..2896467ca3cd 100644
> --- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
> +++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
> @@ -5,6 +5,7 @@
> #include "kprobe_multi_empty.skel.h"
> #include "kprobe_multi_override.skel.h"
> #include "kprobe_multi_session.skel.h"
> +#include "kprobe_multi_session_cookie.skel.h"
> #include "bpf/libbpf_internal.h"
> #include "bpf/hashmap.h"
>
> @@ -373,6 +374,38 @@ static void test_session_skel_api(void)
> kprobe_multi_session__destroy(skel);
> }
>
> +static void test_session_cookie_skel_api(void)
> +{
> + struct kprobe_multi_session_cookie *skel = NULL;
> + LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
> + LIBBPF_OPTS(bpf_test_run_opts, topts);
> + struct bpf_link *link = NULL;
> + int err, prog_fd;
> +
> + skel = kprobe_multi_session_cookie__open_and_load();
> + if (!ASSERT_OK_PTR(skel, "fentry_raw_skel_load"))
> + goto cleanup;
> +
> + skel->bss->pid = getpid();
> +
> + err = kprobe_multi_session_cookie__attach(skel);
> + if (!ASSERT_OK(err, " kprobe_multi_wrapper__attach"))
> + goto cleanup;
> +
> + prog_fd = bpf_program__fd(skel->progs.trigger);
> + err = bpf_prog_test_run_opts(prog_fd, &topts);
> + ASSERT_OK(err, "test_run");
> + ASSERT_EQ(topts.retval, 0, "test_run");
> +
> + ASSERT_EQ(skel->bss->test_kprobe_1_result, 1, "test_kprobe_1_result");
> + ASSERT_EQ(skel->bss->test_kprobe_2_result, 2, "test_kprobe_2_result");
> + ASSERT_EQ(skel->bss->test_kprobe_3_result, 3, "test_kprobe_3_result");
> +
> +cleanup:
> + bpf_link__destroy(link);
> + kprobe_multi_session_cookie__destroy(skel);
> +}
> +
> static size_t symbol_hash(long key, void *ctx __maybe_unused)
> {
> return str_hash((const char *) key);
> @@ -739,4 +772,6 @@ void test_kprobe_multi_test(void)
> test_attach_override();
> 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/kprobe_multi_session_cookie.c b/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c
> new file mode 100644
> index 000000000000..b5c04b7b180c
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c
> @@ -0,0 +1,56 @@
> +// 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_kprobe_1_result = 0;
> +__u64 test_kprobe_2_result = 0;
> +__u64 test_kprobe_3_result = 0;
> +
> +/*
> + * No tests in here, just to trigger 'bpf_fentry_test*'
> + * through tracing test_run
> + */
> +SEC("fentry/bpf_modify_return_test")
> +int BPF_PROG(trigger)
> +{
> + return 0;
> +}
> +
> +static int check_cookie(__u64 val, __u64 *result)
> +{
> + if (bpf_get_current_pid_tgid() >> 32 != pid)
> + return 1;
> +
> + __u64 *cookie = bpf_session_cookie();
we don't enforce this, but let's stick to C89 variable declaration
style (or rather positioning in this case)?
> +
> + if (bpf_session_is_return())
> + *result = *cookie == val ? val : 0;
> + else
> + *cookie = val;
> + return 0;
> +}
> +
> +SEC("kprobe.session/bpf_fentry_test1")
> +int test_kprobe_1(struct pt_regs *ctx)
> +{
> + return check_cookie(1, &test_kprobe_1_result);
> +}
> +
> +SEC("kprobe.session/bpf_fentry_test1")
> +int test_kprobe_2(struct pt_regs *ctx)
> +{
> + return check_cookie(2, &test_kprobe_2_result);
> +}
> +
> +SEC("kprobe.session/bpf_fentry_test1")
> +int test_kprobe_3(struct pt_regs *ctx)
> +{
> + return check_cookie(3, &test_kprobe_3_result);
> +}
> --
> 2.44.0
>
