3 files changed, 81 insertions, 6 deletions

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 124883eaa0cf..604368cfbf02 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -1132,8 +1132,26 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
 		const char *mname;
 
 		mname = btf__name_by_offset(btf, member->name_off);
+		moff = member->offset / 8;
+		mdata = data + moff;
+		msize = btf__resolve_size(btf, member->type);
+		if (msize < 0) {
+			pr_warn("struct_ops init_kern %s: failed to resolve the size of member %s\n",
+				map->name, mname);
+			return msize;
+		}
+
 		kern_member = find_member_by_name(kern_btf, kern_type, mname);
 		if (!kern_member) {
+			/* Skip all zeros or null fields if they are not
+			 * presented in the kernel BTF.
+			 */
+			if (libbpf_is_mem_zeroed(mdata, msize)) {
+				pr_info("struct_ops %s: member %s not found in kernel, skipping it as it's set to zero\n",
+					map->name, mname);
+				continue;
+			}
+
 			pr_warn("struct_ops init_kern %s: Cannot find member %s in kernel BTF\n",
 				map->name, mname);
 			return -ENOTSUP;
@@ -1147,10 +1165,7 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
 			return -ENOTSUP;
 		}
 
-		moff = member->offset / 8;
 		kern_moff = kern_member->offset / 8;
-
-		mdata = data + moff;
 		kern_mdata = kern_data + kern_moff;
 
 		mtype = skip_mods_and_typedefs(btf, member->type, &mtype_id);
@@ -1230,9 +1245,8 @@ static int bpf_map__init_kern_struct_ops(struct bpf_map *map)
 			continue;
 		}
 
-		msize = btf__resolve_size(btf, mtype_id);
 		kern_msize = btf__resolve_size(kern_btf, kern_mtype_id);
-		if (msize < 0 || kern_msize < 0 || msize != kern_msize) {
+		if (kern_msize < 0 || msize != kern_msize) {
 			pr_warn("struct_ops init_kern %s: Error in size of member %s: %zd != %zd(kernel)\n",
 				map->name, mname, (ssize_t)msize,
 				(ssize_t)kern_msize);
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 ee5372c7f2c7..098776d00ab4 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -93,9 +93,56 @@ cleanup:
 	struct_ops_module__destroy(skel);
 }
 
+static void test_struct_ops_not_zeroed(void)
+{
+	struct struct_ops_module *skel;
+	int err;
+
+	/* zeroed is 0, and zeroed_op is null */
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
+		return;
+
+	err = struct_ops_module__load(skel);
+	ASSERT_OK(err, "struct_ops_module_load");
+
+	struct_ops_module__destroy(skel);
+
+	/* zeroed is not 0 */
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open_not_zeroed"))
+		return;
+
+	/* libbpf should reject the testmod_zeroed since struct
+	 * bpf_testmod_ops in the kernel has no "zeroed" field and the
+	 * value of "zeroed" is non-zero.
+	 */
+	skel->struct_ops.testmod_zeroed->zeroed = 0xdeadbeef;
+	err = struct_ops_module__load(skel);
+	ASSERT_ERR(err, "struct_ops_module_load_not_zeroed");
+
+	struct_ops_module__destroy(skel);
+
+	/* zeroed_op is not null */
+	skel = struct_ops_module__open();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_module_open_not_zeroed_op"))
+		return;
+
+	/* libbpf should reject the testmod_zeroed since the value of its
+	 * "zeroed_op" is not null.
+	 */
+	skel->struct_ops.testmod_zeroed->zeroed_op = skel->progs.test_3;
+	err = struct_ops_module__load(skel);
+	ASSERT_ERR(err, "struct_ops_module_load_not_zeroed_op");
+
+	struct_ops_module__destroy(skel);
+}
+
 void serial_test_struct_ops_module(void)
 {
 	if (test__start_subtest("test_struct_ops_load"))
 		test_struct_ops_load();
+	if (test__start_subtest("test_struct_ops_not_zeroed"))
+		test_struct_ops_not_zeroed();
 }
 
diff --git a/tools/testing/selftests/bpf/progs/struct_ops_module.c b/tools/testing/selftests/bpf/progs/struct_ops_module.c
index 026cabfa7f1f..86e1e50c5531 100644
--- a/tools/testing/selftests/bpf/progs/struct_ops_module.c
+++ b/tools/testing/selftests/bpf/progs/struct_ops_module.c
@@ -23,7 +23,7 @@ void BPF_PROG(test_2, int a, int b)
 	test_2_result = a + b;
 }
 
-SEC("struct_ops/test_3")
+SEC("?struct_ops/test_3")
 int BPF_PROG(test_3, int a, int b)
 {
 	test_2_result = a + b + 3;
@@ -54,3 +54,17 @@ struct bpf_testmod_ops___v2 testmod_2 = {
 	.test_1 = (void *)test_1,
 	.test_2 = (void *)test_2_v2,
 };
+
+struct bpf_testmod_ops___zeroed {
+	int (*test_1)(void);
+	void (*test_2)(int a, int b);
+	int (*test_maybe_null)(int dummy, struct task_struct *task);
+	void (*zeroed_op)(int a, int b);
+	int zeroed;
+};
+
+SEC(".struct_ops.link")
+struct bpf_testmod_ops___zeroed testmod_zeroed = {
+	.test_1 = (void *)test_1,
+	.test_2 = (void *)test_2_v2,
+};