From 504d21d905002f2b3e2a8703a3d4630a680362e2 Mon Sep 17 00:00:00 2001
From: Jiri Olsa <jolsa@kernel.org>
Date: Fri, 8 Nov 2024 14:45:41 +0100
Subject: [PATCH] selftests/bpf: Add kprobe session verifier test for return
 value

Making sure kprobe.session program can return only [0,1] values.

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/20241108134544.480660-11-jolsa@kernel.org
---
 .../bpf/prog_tests/kprobe_multi_test.c        |  2 ++
 .../bpf/progs/kprobe_multi_verifier.c         | 31 +++++++++++++++++++
 2 files changed, 33 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/kprobe_multi_verifier.c

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 960c9323d1e0..66ab1cae923e 100644
--- a/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
+++ b/tools/testing/selftests/bpf/prog_tests/kprobe_multi_test.c
@@ -6,6 +6,7 @@
 #include "kprobe_multi_override.skel.h"
 #include "kprobe_multi_session.skel.h"
 #include "kprobe_multi_session_cookie.skel.h"
+#include "kprobe_multi_verifier.skel.h"
 #include "bpf/libbpf_internal.h"
 #include "bpf/hashmap.h"
 
@@ -764,4 +765,5 @@ void test_kprobe_multi_test(void)
 		test_session_skel_api();
 	if (test__start_subtest("session_cookie"))
 		test_session_cookie_skel_api();
+	RUN_TESTS(kprobe_multi_verifier);
 }
diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi_verifier.c b/tools/testing/selftests/bpf/progs/kprobe_multi_verifier.c
new file mode 100644
index 000000000000..288577e81deb
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi_verifier.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/usdt.bpf.h>
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+
+SEC("kprobe.session")
+__success
+int kprobe_session_return_0(struct pt_regs *ctx)
+{
+	return 0;
+}
+
+SEC("kprobe.session")
+__success
+int kprobe_session_return_1(struct pt_regs *ctx)
+{
+	return 1;
+}
+
+SEC("kprobe.session")
+__failure
+__msg("At program exit the register R0 has smin=2 smax=2 should have been in [0, 1]")
+int kprobe_session_return_2(struct pt_regs *ctx)
+{
+	return 2;
+}