selftests/bpf: Add kprobe session cookie test

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

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/20240430112830.1184228-8-jolsa@kernel.org

1 files changed, 58 insertions, 0 deletions

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..d49070803e22
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi_session_cookie.c
@@ -0,0 +1,58 @@
+// 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)
+{
+	long *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("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);
+}