[PATCH bpf-next v3 2/2] selftests/bpf: Add a negative test for stack accounting in jit mode

[Yonghong Song <yonghong.song@xxxxxxxxx>]

The new test is very similar to test_global_func1.c, but
is modified to fail on jit mode.

Signed-off-by: Yonghong Song <yonghong.song@xxxxxxxxx>
---
 .../bpf/prog_tests/test_global_funcs.c        |  3 ++
 .../selftests/bpf/progs/test_global_func18.c  | 44 +++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/progs/test_global_func18.c

diff --git a/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c b/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c
index a3a41680b38e..dccbf2213135 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_global_funcs.c
@@ -18,6 +18,7 @@
 #include "test_global_func15.skel.h"
 #include "test_global_func16.skel.h"
 #include "test_global_func17.skel.h"
+#include "test_global_func18.skel.h"
 #include "test_global_func_ctx_args.skel.h"
 
 #include "bpf/libbpf_internal.h"
@@ -140,6 +141,8 @@ void test_test_global_funcs(void)
 {
 	if (!env.jit_enabled) {
 		RUN_TESTS(test_global_func1);
+	} else {
+		RUN_TESTS(test_global_func18);
 	}
 
 	RUN_TESTS(test_global_func2);
diff --git a/tools/testing/selftests/bpf/progs/test_global_func18.c b/tools/testing/selftests/bpf/progs/test_global_func18.c
new file mode 100644
index 000000000000..d1aa3b2c68fe
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_global_func18.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+#include <stddef.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+#define MAX_STACK1 (512 - 3 * 32 + 8)
+#define MAX_STACK2 (3 * 32)
+
+__attribute__ ((noinline))
+int f1(struct __sk_buff *skb)
+{
+	return skb->len;
+}
+
+int f3(int, struct __sk_buff *skb, int);
+
+__attribute__ ((noinline))
+int f2(int val, struct __sk_buff *skb)
+{
+	volatile char buf[MAX_STACK1] = {};
+
+	__sink(buf[MAX_STACK1 - 1]);
+
+	return f1(skb) + f3(val, skb, 1);
+}
+
+__attribute__ ((noinline))
+int f3(int val, struct __sk_buff *skb, int var)
+{
+	volatile char buf[MAX_STACK2] = {};
+
+	__sink(buf[MAX_STACK2 - 1]);
+
+	return skb->ifindex * val * var;
+}
+
+SEC("tc")
+__failure __msg("combined stack size of 3 calls is 528")
+int global_func18(struct __sk_buff *skb)
+{
+	return f1(skb) + f2(2, skb) + f3(3, skb, 4);
+}
-- 
2.39.3