selftests/bpf: Test outer map update operations in syscall program

Syscall program is running with rcu_read_lock_trace being held, so if
bpf_map_update_elem() or bpf_map_delete_elem() invokes
synchronize_rcu_tasks_trace() when operating on an outer map, there will
be dead-lock, so add a test to guarantee that it is dead-lock free.

Signed-off-by: Hou Tao <houtao1@huawei.com>
Link: https://lore.kernel.org/r/20231204140425.1480317-8-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 28 insertions, 2 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/syscall.c b/tools/testing/selftests/bpf/prog_tests/syscall.c
index f4d40001155a..0be8301c0ffd 100644
--- a/tools/testing/selftests/bpf/prog_tests/syscall.c
+++ b/tools/testing/selftests/bpf/prog_tests/syscall.c
@@ -12,7 +12,7 @@ struct args {
 	int btf_fd;
 };
 
-void test_syscall(void)
+static void test_syscall_load_prog(void)
 {
 	static char verifier_log[8192];
 	struct args ctx = {
@@ -32,7 +32,7 @@ void test_syscall(void)
 	if (!ASSERT_OK_PTR(skel, "skel_load"))
 		goto cleanup;
 
-	prog_fd = bpf_program__fd(skel->progs.bpf_prog);
+	prog_fd = bpf_program__fd(skel->progs.load_prog);
 	err = bpf_prog_test_run_opts(prog_fd, &tattr);
 	ASSERT_EQ(err, 0, "err");
 	ASSERT_EQ(tattr.retval, 1, "retval");
@@ -53,3 +53,29 @@ cleanup:
 	if (ctx.btf_fd > 0)
 		close(ctx.btf_fd);
 }
+
+static void test_syscall_update_outer_map(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts);
+	struct syscall *skel;
+	int err, prog_fd;
+
+	skel = syscall__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_load"))
+		goto cleanup;
+
+	prog_fd = bpf_program__fd(skel->progs.update_outer_map);
+	err = bpf_prog_test_run_opts(prog_fd, &opts);
+	ASSERT_EQ(err, 0, "err");
+	ASSERT_EQ(opts.retval, 1, "retval");
+cleanup:
+	syscall__destroy(skel);
+}
+
+void test_syscall(void)
+{
+	if (test__start_subtest("load_prog"))
+		test_syscall_load_prog();
+	if (test__start_subtest("update_outer_map"))
+		test_syscall_update_outer_map();
+}