selftests/bpf: Ensure the unsupported struct_ops prog cannot be loaded

There is an existing "bpf_tcp_ca/unsupp_cong_op" test to ensure
the unsupported tcp-cc "get_info" struct_ops prog cannot be loaded.

This patch adds a new test in the bpf_testmod such that the
unsupported ops test does not depend on other kernel subsystem
where its supporting ops may be changed in the future.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240722183049.2254692-4-martin.lau@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
index 23fa1872ee674f5b224587e525c4afb1a379d02d..fe0d402b0d6531fa3113acc2ab3123ff1cdd29fa 100644 (file)
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
@@ -35,6 +35,7 @@ struct bpf_testmod_ops {
        void (*test_2)(int a, int b);
        /* Used to test nullable arguments. */
        int (*test_maybe_null)(int dummy, struct task_struct *task);
+       int (*unsupported_ops)(void);
 
        /* The following fields are used to test shadow copies. */
        char onebyte;

diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
index bbcf12696a6bc8002b024f45bd181f536d53a3c4..75a0dea511b3f2259fdf544d67e14b53df14b221 100644 (file)
--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -9,6 +9,7 @@
 #include "struct_ops_nulled_out_cb.skel.h"
 #include "struct_ops_forgotten_cb.skel.h"
 #include "struct_ops_detach.skel.h"
+#include "unsupported_ops.skel.h"
 
 static void check_map_info(struct bpf_map_info *info)
 {
@@ -311,5 +312,6 @@ void serial_test_struct_ops_module(void)
                test_struct_ops_forgotten_cb();
        if (test__start_subtest("test_detach_link"))
                test_detach_link();
+       RUN_TESTS(unsupported_ops);
 }
 

diff --git a/tools/testing/selftests/bpf/progs/unsupported_ops.c b/tools/testing/selftests/bpf/progs/unsupported_ops.c
new file mode 100644 (file)
index 0000000..9180365
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/unsupported_ops.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_misc.h"
+#include "../bpf_testmod/bpf_testmod.h"
+
+char _license[] SEC("license") = "GPL";
+
+SEC("struct_ops/unsupported_ops")
+__failure
+__msg("attach to unsupported member unsupported_ops of struct bpf_testmod_ops")
+int BPF_PROG(unsupported_ops)
+{
+       return 0;
+}
+
+SEC(".struct_ops.link")
+struct bpf_testmod_ops testmod = {
+       .unsupported_ops = (void *)unsupported_ops,
+};