2 files changed, 97 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/tailcalls.c b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
index c4da87ec3ba4..19c70880cfb3 100644
--- a/tools/testing/selftests/bpf/prog_tests/tailcalls.c
+++ b/tools/testing/selftests/bpf/prog_tests/tailcalls.c
@@ -831,6 +831,59 @@ out:
 	bpf_object__close(obj);
 }
 
+#include "tailcall_bpf2bpf6.skel.h"
+
+/* Tail call counting works even when there is data on stack which is
+ * not aligned to 8 bytes.
+ */
+static void test_tailcall_bpf2bpf_6(void)
+{
+	struct tailcall_bpf2bpf6 *obj;
+	int err, map_fd, prog_fd, main_fd, data_fd, i, val;
+	LIBBPF_OPTS(bpf_test_run_opts, topts,
+		.data_in = &pkt_v4,
+		.data_size_in = sizeof(pkt_v4),
+		.repeat = 1,
+	);
+
+	obj = tailcall_bpf2bpf6__open_and_load();
+	if (!ASSERT_OK_PTR(obj, "open and load"))
+		return;
+
+	main_fd = bpf_program__fd(obj->progs.entry);
+	if (!ASSERT_GE(main_fd, 0, "entry prog fd"))
+		goto out;
+
+	map_fd = bpf_map__fd(obj->maps.jmp_table);
+	if (!ASSERT_GE(map_fd, 0, "jmp_table map fd"))
+		goto out;
+
+	prog_fd = bpf_program__fd(obj->progs.classifier_0);
+	if (!ASSERT_GE(prog_fd, 0, "classifier_0 prog fd"))
+		goto out;
+
+	i = 0;
+	err = bpf_map_update_elem(map_fd, &i, &prog_fd, BPF_ANY);
+	if (!ASSERT_OK(err, "jmp_table map update"))
+		goto out;
+
+	err = bpf_prog_test_run_opts(main_fd, &topts);
+	ASSERT_OK(err, "entry prog test run");
+	ASSERT_EQ(topts.retval, 0, "tailcall retval");
+
+	data_fd = bpf_map__fd(obj->maps.bss);
+	if (!ASSERT_GE(map_fd, 0, "bss map fd"))
+		goto out;
+
+	i = 0;
+	err = bpf_map_lookup_elem(data_fd, &i, &val);
+	ASSERT_OK(err, "bss map lookup");
+	ASSERT_EQ(val, 1, "done flag is set");
+
+out:
+	tailcall_bpf2bpf6__destroy(obj);
+}
+
 void test_tailcalls(void)
 {
 	if (test__start_subtest("tailcall_1"))
@@ -855,4 +908,6 @@ void test_tailcalls(void)
 		test_tailcall_bpf2bpf_4(false);
 	if (test__start_subtest("tailcall_bpf2bpf_5"))
 		test_tailcall_bpf2bpf_4(true);
+	if (test__start_subtest("tailcall_bpf2bpf_6"))
+		test_tailcall_bpf2bpf_6();
 }
diff --git a/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c b/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c
new file mode 100644
index 000000000000..41ce83da78e8
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/tailcall_bpf2bpf6.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+#define __unused __attribute__((unused))
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
+	__uint(max_entries, 1);
+	__uint(key_size, sizeof(__u32));
+	__uint(value_size, sizeof(__u32));
+} jmp_table SEC(".maps");
+
+int done = 0;
+
+SEC("tc")
+int classifier_0(struct __sk_buff *skb __unused)
+{
+	done = 1;
+	return 0;
+}
+
+static __noinline
+int subprog_tail(struct __sk_buff *skb)
+{
+	/* Don't propagate the constant to the caller */
+	volatile int ret = 1;
+
+	bpf_tail_call_static(skb, &jmp_table, 0);
+	return ret;
+}
+
+SEC("tc")
+int entry(struct __sk_buff *skb)
+{
+	/* Have data on stack which size is not a multiple of 8 */
+	volatile char arr[1] = {};
+
+	return subprog_tail(skb);
+}
+
+char __license[] SEC("license") = "GPL";