[bpf-next,7/7] selftests/bpf: Add kprobe multi wrapper cookie test

Commit Message

Jiri Olsa April 22, 2024, 12:12 p.m. UTC

Adding kprobe multi session test that verifies the cookie
value get properly propagated from entry to return program.

Signed-off-by: Jiri Olsa <[e-mail]>
---
 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

Comments

Andrii Nakryiko April 24, 2024, 12:27 a.m. UTC | #1

On Mon, Apr 22, 2024 at 5:14 AM Jiri Olsa <[e-mail]> wrote:
>
> Adding kprobe multi session test that verifies the cookie
> value get properly propagated from entry to return program.
>
> Signed-off-by: Jiri Olsa <[e-mail]>
> ---

Forgot to update subject (still using "wrapper" naming)

overall LGTM, see nits

Acked-by: Andrii Nakryiko <[e-mail]>

>  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
>

Jiri Olsa April 24, 2024, 11:44 a.m. UTC | #2

On Tue, Apr 23, 2024 at 05:27:22PM -0700, Andrii Nakryiko wrote:
> On Mon, Apr 22, 2024 at 5:14 AM Jiri Olsa <[e-mail]> wrote:
> >
> > Adding kprobe multi session test that verifies the cookie
> > value get properly propagated from entry to return program.
> >
> > Signed-off-by: Jiri Olsa <[e-mail]>
> > ---
> 
> Forgot to update subject (still using "wrapper" naming)

ugh, thnx

> 
> overall LGTM, see nits
> 
> Acked-by: Andrii Nakryiko <[e-mail]>
> 
> >  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.

ok, there are some __u64 in kfuncs already, but let's stay on safe side

SNIP

> > +/*
> > + * 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)?

ok, will change that

jirka

Patch

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;
 #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();
+
+	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);
+}