[PATCH bpf-next v11 13/13] selftests/bpf: test case for register_bpf_struct_ops().

thinker.li
2023-11-06T20:13:25Z

From: Kui-Feng Lee <thinker.li@gmail.com>

Create a new struct_ops type called bpf_testmod_ops within the bpf_testmod
module. When a struct_ops object is registered, the bpf_testmod module will
invoke test_2 from the module.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
.../selftests/bpf/bpf_testmod/bpf_testmod.c | 59 +++++++
.../selftests/bpf/bpf_testmod/bpf_testmod.h | 5 +
.../bpf/prog_tests/test_struct_ops_module.c | 144 ++++++++++++++++++
.../selftests/bpf/progs/struct_ops_module.c | 30 ++++
.../testing/selftests/bpf/progs/testmod_btf.c | 26 ++++
5 files changed, 264 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
create mode 100644 tools/testing/selftests/bpf/progs/struct_ops_module.c
create mode 100644 tools/testing/selftests/bpf/progs/testmod_btf.c

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index a5e246f7b202..418e10311c33 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2020 Facebook */
+#include <linux/bpf.h>
#include <linux/btf.h>
#include <linux/btf_ids.h>
#include <linux/error-injection.h>
@@ -522,11 +523,66 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
BTF_SET8_END(bpf_testmod_check_kfunc_ids)

+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+
+DEFINE_STRUCT_OPS_VALUE_TYPE(bpf_testmod_ops);
+
+static int bpf_testmod_ops_init(struct btf *btf)
+{
+ return 0;
+}
+
+static bool bpf_testmod_ops_is_valid_access(int off, int size,
+ enum bpf_access_type type,
+ const struct bpf_prog *prog,
+ struct bpf_insn_access_aux *info)
+{
+ return bpf_tracing_btf_ctx_access(off, size, type, prog, info);
+}
+
+static int bpf_testmod_ops_init_member(const struct btf_type *t,
+ const struct btf_member *member,
+ void *kdata, const void *udata)
+{
+ return 0;
+}
+
static const struct btf_kfunc_id_set bpf_testmod_kfunc_set = {
.owner = THIS_MODULE,
.set = &bpf_testmod_check_kfunc_ids,
};

+static const struct bpf_verifier_ops bpf_testmod_verifier_ops = {
+ .is_valid_access = bpf_testmod_ops_is_valid_access,
+};
+
+static int bpf_dummy_reg(void *kdata)
+{
+ struct bpf_testmod_ops *ops = kdata;
+ int r;
+
+ BTF_STRUCT_OPS_TYPE_EMIT(bpf_testmod_ops);
+ r = ops->test_2(4, 3);
+
+ return 0;
+}
+
+static void bpf_dummy_unreg(void *kdata)
+{
+}
+
+struct bpf_struct_ops bpf_bpf_testmod_ops = {
+ .verifier_ops = &bpf_testmod_verifier_ops,
+ .init = bpf_testmod_ops_init,
+ .init_member = bpf_testmod_ops_init_member,
+ .reg = bpf_dummy_reg,
+ .unreg = bpf_dummy_unreg,
+ .name = "bpf_testmod_ops",
+ .owner = THIS_MODULE,
+};
+
+#endif /* CONFIG_DEBUG_INFO_BTF_MODULES */
+
extern int bpf_fentry_test1(int a);

static int bpf_testmod_init(void)
@@ -537,6 +593,9 @@ static int bpf_testmod_init(void)
ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &bpf_testmod_kfunc_set);
ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &bpf_testmod_kfunc_set);
ret = ret ?: register_btf_kfunc_id_set(BPF_PROG_TYPE_SYSCALL, &bpf_testmod_kfunc_set);
+#ifdef CONFIG_DEBUG_INFO_BTF_MODULES
+ ret = ret ?: register_bpf_struct_ops(&bpf_bpf_testmod_ops);
+#endif
if (ret < 0)
return ret;
if (bpf_fentry_test1(0) < 0)
diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
index f32793efe095..ca5435751c79 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.h
@@ -28,4 +28,9 @@ struct bpf_iter_testmod_seq {
int cnt;
};

+struct bpf_testmod_ops {
+ int (*test_1)(void);
+ int (*test_2)(int a, int b);
+};
+
#endif /* _BPF_TESTMOD_H */
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
new file mode 100644
index 000000000000..49f4a4460642
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -0,0 +1,144 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+#include <test_progs.h>
+#include <time.h>
+
+#include "rcu_tasks_trace_gp.skel.h"
+#include "struct_ops_module.skel.h"
+#include "testmod_btf.skel.h"
+
+static void test_regular_load(void)
+{
+ struct struct_ops_module *skel;
+ DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
+ struct bpf_link *link;
+ int err;
+
+ skel = struct_ops_module__open_opts(&opts);
+ if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
+ return;
+ err = struct_ops_module__load(skel);
+ if (!ASSERT_OK(err, "struct_ops_module_load"))
+ goto cleanup;
+
+ link = bpf_map__attach_struct_ops(skel->maps.testmod_1);
+ ASSERT_OK_PTR(link, "attach_test_mod_1");
+
+ /* test_2() will be called from bpf_dummy_reg() in bpf_testmod.c */
+ ASSERT_EQ(skel->bss->test_2_result, 7, "test_2_result");
+
+ bpf_link__destroy(link);
+
+cleanup:
+ struct_ops_module__destroy(skel);
+}
+
+static void test_load_without_module(void)
+{
+ struct struct_ops_module *skel = NULL;
+ struct testmod_btf *skel_btf;
+ DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
+ struct bpf_link *link_btf = NULL;;
+ int err, i;
+
+ skel_btf = testmod_btf__open_and_load();
+ if (!ASSERT_OK_PTR(skel_btf, "testmod_btf_open"))
+ return;
+
+ link_btf = bpf_program__attach(skel_btf->progs.kprobe_btf_put);
+ if (!ASSERT_OK_PTR(link_btf, "kprobe_btf_put_attach"))
+ goto cleanup;
+
+ err = unload_bpf_testmod(false);
+ if (!ASSERT_OK(err, "unload_bpf_testmod"))
+ goto cleanup;
+
+ skel = struct_ops_module__open_opts(&opts);
+ if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
+ goto cleanup;
+ err = struct_ops_module__load(skel);
+ ASSERT_ERR(err, "struct_ops_module_load");
+
+ /* Wait for the struct_ops map to be freed. Struct_ops maps hold a
+ * refcount to the module btf. And, this function unloads and then
+ * loads bpf_testmod. Without waiting the map to be freed, the next
+ * test may fail since libbpf may use the old btf that is still
+ * alive instead of the new one that is created for the newly
+ * loaded module.
+ */
+ for (i = 0; i < 10; i++) {
+ if (skel_btf->bss->bpf_testmod_put)
+ break;
+ usleep(100000);
+ }
+ ASSERT_EQ(skel_btf->bss->bpf_testmod_put, 1, "btf_put");
+
+cleanup:
+ bpf_link__destroy(link_btf);
+ struct_ops_module__destroy(skel);
+ testmod_btf__destroy(skel_btf);
+ /* Without this, the next test may fail */
+ load_bpf_testmod(false);
+}
+
+static void test_attach_without_module(void)
+{
+ struct struct_ops_module *skel = NULL;
+ struct testmod_btf *skel_btf;
+ struct bpf_link *link, *link_btf = NULL;
+ DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
+ int err, i;
+
+ skel_btf = testmod_btf__open_and_load();
+ if (!ASSERT_OK_PTR(skel_btf, "testmod_btf_open"))
+ return;
+
+ link_btf = bpf_program__attach(skel_btf->progs.kprobe_btf_put);
+ if (!ASSERT_OK_PTR(link_btf, "kprobe_btf_put_attach"))
+ goto cleanup;
+
+ skel = struct_ops_module__open_opts(&opts);
+ if (!ASSERT_OK_PTR(skel, "struct_ops_module_open"))
+ goto cleanup;
+ err = struct_ops_module__load(skel);
+ if (!ASSERT_OK(err, "struct_ops_module_load"))
+ goto cleanup;
+
+ err = unload_bpf_testmod(false);
+ if (!ASSERT_OK(err, "unload_bpf_testmod"))
+ goto cleanup;
+
+ link = bpf_map__attach_struct_ops(skel->maps.testmod_1);
+ ASSERT_ERR_PTR(link, "attach_test_mod_1");
+
+ struct_ops_module__destroy(skel);
+ skel = NULL;
+
+ /* Wait for the struct_ops map to be freed */
+ for (i = 0; i < 10; i++) {
+ if (skel_btf->bss->bpf_testmod_put)
+ break;
+ usleep(100000);
+ }
+ ASSERT_EQ(skel_btf->bss->bpf_testmod_put, 1, "btf_put");
+
+cleanup:
+ bpf_link__destroy(link_btf);
+ struct_ops_module__destroy(skel);
+ testmod_btf__destroy(skel_btf);
+ /* Without this, the next test may fail */
+ load_bpf_testmod(false);
+}
+
+void serial_test_struct_ops_module(void)
+{
+ if (test__start_subtest("regular_load"))
+ test_regular_load();
+
+ if (test__start_subtest("load_without_module"))
+ test_load_without_module();
+
+ if (test__start_subtest("attach_without_module"))
+ test_attach_without_module();
+}
+
diff --git a/tools/testing/selftests/bpf/progs/struct_ops_module.c b/tools/testing/selftests/bpf/progs/struct_ops_module.c
new file mode 100644
index 000000000000..cb305d04342f
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/struct_ops_module.c
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "../bpf_testmod/bpf_testmod.h"
+
+char _license[] SEC("license") = "GPL";
+
+int test_2_result = 0;
+
+SEC("struct_ops/test_1")
+int BPF_PROG(test_1)
+{
+ return 0xdeadbeef;
+}
+
+SEC("struct_ops/test_2")
+int BPF_PROG(test_2, int a, int b)
+{
+ test_2_result = a + b;
+ return a + b;
+}
+
+SEC(".struct_ops.link")
+struct bpf_testmod_ops testmod_1 = {
+ .test_1 = (void *)test_1,
+ .test_2 = (void *)test_2,
+};
+
diff --git a/tools/testing/selftests/bpf/progs/testmod_btf.c b/tools/testing/selftests/bpf/progs/testmod_btf.c
new file mode 100644
index 000000000000..cfcd269f07fe
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/testmod_btf.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
+#include <vmlinux.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+
+char _license[] SEC("license") = "GPL";
+
+int bpf_testmod_put = 0;
+
+SEC("kprobe/btf_put")
+int BPF_KPROBE(kprobe_btf_put, struct btf *btf)
+{
+ const char name[] = "bpf_testmod";
+ int i;
+
+ for (i = 0; i < sizeof(name); i++) {
+ if (BPF_CORE_READ(btf, name[i]) != name[i])
+ return 0;
+ }
+
+ if (BPF_CORE_READ(btf, refcnt.refs.counter) == 1)
+ bpf_testmod_put = 1;
+
+ return 0;
+}
--
2.34.1