selftests/bpf: Add uprobe session recursive test

Adding uprobe session test that verifies the cookie value is stored
properly when single uprobe-ed function is executed recursively.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241108134544.480660-9-jolsa@kernel.org

1 files changed, 57 insertions, 0 deletions

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 986852ec26f5..b9448fb63a19 100644
--- a/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/uprobe_multi_test.c
@@ -10,6 +10,7 @@
 #include "uprobe_multi_pid_filter.skel.h"
 #include "uprobe_multi_session.skel.h"
 #include "uprobe_multi_session_cookie.skel.h"
+#include "uprobe_multi_session_recursive.skel.h"
 #include "bpf/libbpf_internal.h"
 #include "testing_helpers.h"
 #include "../sdt.h"
@@ -36,6 +37,12 @@ noinline void usdt_trigger(void)
 	STAP_PROBE(test, pid_filter_usdt);
 }
 
+noinline void uprobe_session_recursive(int i)
+{
+	if (i)
+		uprobe_session_recursive(i - 1);
+}
+
 struct child {
 	int go[2];
 	int c2p[2]; /* child -> parent channel */
@@ -1091,6 +1098,54 @@ cleanup:
 	uprobe_multi_session_cookie__destroy(skel);
 }
 
+static void test_session_recursive_skel_api(void)
+{
+	struct uprobe_multi_session_recursive *skel = NULL;
+	int i, err;
+
+	skel = uprobe_multi_session_recursive__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "uprobe_multi_session_recursive__open_and_load"))
+		goto cleanup;
+
+	skel->bss->pid = getpid();
+
+	err = uprobe_multi_session_recursive__attach(skel);
+	if (!ASSERT_OK(err, "uprobe_multi_session_recursive__attach"))
+		goto cleanup;
+
+	for (i = 0; i < ARRAY_SIZE(skel->bss->test_uprobe_cookie_entry); i++)
+		skel->bss->test_uprobe_cookie_entry[i] = i + 1;
+
+	uprobe_session_recursive(5);
+
+	/*
+	 *                                         entry uprobe:
+	 * uprobe_session_recursive(5) {             *cookie = 1, return 0
+	 *   uprobe_session_recursive(4) {           *cookie = 2, return 1
+	 *     uprobe_session_recursive(3) {         *cookie = 3, return 0
+	 *       uprobe_session_recursive(2) {       *cookie = 4, return 1
+	 *         uprobe_session_recursive(1) {     *cookie = 5, return 0
+	 *           uprobe_session_recursive(0) {   *cookie = 6, return 1
+	 *                                          return uprobe:
+	 *           } i = 0                          not executed
+	 *         } i = 1                            test_uprobe_cookie_return[0] = 5
+	 *       } i = 2                              not executed
+	 *     } i = 3                                test_uprobe_cookie_return[1] = 3
+	 *   } i = 4                                  not executed
+	 * } i = 5                                    test_uprobe_cookie_return[2] = 1
+	 */
+
+	ASSERT_EQ(skel->bss->idx_entry, 6, "idx_entry");
+	ASSERT_EQ(skel->bss->idx_return, 3, "idx_return");
+
+	ASSERT_EQ(skel->bss->test_uprobe_cookie_return[0], 5, "test_uprobe_cookie_return[0]");
+	ASSERT_EQ(skel->bss->test_uprobe_cookie_return[1], 3, "test_uprobe_cookie_return[1]");
+	ASSERT_EQ(skel->bss->test_uprobe_cookie_return[2], 1, "test_uprobe_cookie_return[2]");
+
+cleanup:
+	uprobe_multi_session_recursive__destroy(skel);
+}
+
 static void test_bench_attach_uprobe(void)
 {
 	long attach_start_ns = 0, attach_end_ns = 0;
@@ -1191,4 +1246,6 @@ void test_uprobe_multi_test(void)
 		test_session_skel_api();
 	if (test__start_subtest("session_cookie"))
 		test_session_cookie_skel_api();
+	if (test__start_subtest("session_cookie_recursive"))
+		test_session_recursive_skel_api();
 }