Daniel Borkmann says:

====================
bpf-next 2022-11-25

We've added 101 non-merge commits during the last 11 day(s) which contain
a total of 109 files changed, 8827 insertions(+), 1129 deletions(-).

The main changes are:

1) Support for user defined BPF objects: the use case is to allocate own
   objects, build own object hierarchies and use the building blocks to
   build own data structures flexibly, for example, linked lists in BPF,
   from Kumar Kartikeya Dwivedi.

2) Add bpf_rcu_read_{,un}lock() support for sleepable programs,
   from Yonghong Song.

3) Add support storing struct task_struct objects as kptrs in maps,
   from David Vernet.

4) Batch of BPF map documentation improvements, from Maryam Tahhan
   and Donald Hunter.

5) Improve BPF verifier to propagate nullness information for branches
   of register to register comparisons, from Eduard Zingerman.

6) Fix cgroup BPF iter infra to hold reference on the start cgroup,
   from Hou Tao.

7) Fix BPF verifier to not mark fentry/fexit program arguments as trusted
   given it is not the case for them, from Alexei Starovoitov.

8) Improve BPF verifier's realloc handling to better play along with dynamic
   runtime analysis tools like KASAN and friends, from Kees Cook.

9) Remove legacy libbpf mode support from bpftool,
   from Sahid Orentino Ferdjaoui.

10) Rework zero-len skb redirection checks to avoid potentially breaking
    existing BPF test infra users, from Stanislav Fomichev.

11) Two small refactorings which are independent and have been split out
    of the XDP queueing RFC series, from Toke Høiland-Jørgensen.

12) Fix a memory leak in LSM cgroup BPF selftest, from Wang Yufen.

13) Documentation on how to run BPF CI without patch submission,
    from Daniel Müller.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
====================

Link: https://lore.kernel.org/r/20221125012450.441-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 740 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/linked_list.c b/tools/testing/selftests/bpf/prog_tests/linked_list.c
new file mode 100644
index 000000000000..9a7d4c47af63
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/linked_list.c
@@ -0,0 +1,740 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <bpf/btf.h>
+#include <test_btf.h>
+#include <linux/btf.h>
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "linked_list.skel.h"
+#include "linked_list_fail.skel.h"
+
+static char log_buf[1024 * 1024];
+
+static struct {
+	const char *prog_name;
+	const char *err_msg;
+} linked_list_fail_tests[] = {
+#define TEST(test, off) \
+	{ #test "_missing_lock_push_front", \
+	  "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \
+	{ #test "_missing_lock_push_back", \
+	  "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \
+	{ #test "_missing_lock_pop_front", \
+	  "bpf_spin_lock at off=" #off " must be held for bpf_list_head" }, \
+	{ #test "_missing_lock_pop_back", \
+	  "bpf_spin_lock at off=" #off " must be held for bpf_list_head" },
+	TEST(kptr, 32)
+	TEST(global, 16)
+	TEST(map, 0)
+	TEST(inner_map, 0)
+#undef TEST
+#define TEST(test, op) \
+	{ #test "_kptr_incorrect_lock_" #op, \
+	  "held lock and object are not in the same allocation\n" \
+	  "bpf_spin_lock at off=32 must be held for bpf_list_head" }, \
+	{ #test "_global_incorrect_lock_" #op, \
+	  "held lock and object are not in the same allocation\n" \
+	  "bpf_spin_lock at off=16 must be held for bpf_list_head" }, \
+	{ #test "_map_incorrect_lock_" #op, \
+	  "held lock and object are not in the same allocation\n" \
+	  "bpf_spin_lock at off=0 must be held for bpf_list_head" }, \
+	{ #test "_inner_map_incorrect_lock_" #op, \
+	  "held lock and object are not in the same allocation\n" \
+	  "bpf_spin_lock at off=0 must be held for bpf_list_head" },
+	TEST(kptr, push_front)
+	TEST(kptr, push_back)
+	TEST(kptr, pop_front)
+	TEST(kptr, pop_back)
+	TEST(global, push_front)
+	TEST(global, push_back)
+	TEST(global, pop_front)
+	TEST(global, pop_back)
+	TEST(map, push_front)
+	TEST(map, push_back)
+	TEST(map, pop_front)
+	TEST(map, pop_back)
+	TEST(inner_map, push_front)
+	TEST(inner_map, push_back)
+	TEST(inner_map, pop_front)
+	TEST(inner_map, pop_back)
+#undef TEST
+	{ "map_compat_kprobe", "tracing progs cannot use bpf_list_head yet" },
+	{ "map_compat_kretprobe", "tracing progs cannot use bpf_list_head yet" },
+	{ "map_compat_tp", "tracing progs cannot use bpf_list_head yet" },
+	{ "map_compat_perf", "tracing progs cannot use bpf_list_head yet" },
+	{ "map_compat_raw_tp", "tracing progs cannot use bpf_list_head yet" },
+	{ "map_compat_raw_tp_w", "tracing progs cannot use bpf_list_head yet" },
+	{ "obj_type_id_oor", "local type ID argument must be in range [0, U32_MAX]" },
+	{ "obj_new_no_composite", "bpf_obj_new type ID argument must be of a struct" },
+	{ "obj_new_no_struct", "bpf_obj_new type ID argument must be of a struct" },
+	{ "obj_drop_non_zero_off", "R1 must have zero offset when passed to release func" },
+	{ "new_null_ret", "R0 invalid mem access 'ptr_or_null_'" },
+	{ "obj_new_acq", "Unreleased reference id=" },
+	{ "use_after_drop", "invalid mem access 'scalar'" },
+	{ "ptr_walk_scalar", "type=scalar expected=percpu_ptr_" },
+	{ "direct_read_lock", "direct access to bpf_spin_lock is disallowed" },
+	{ "direct_write_lock", "direct access to bpf_spin_lock is disallowed" },
+	{ "direct_read_head", "direct access to bpf_list_head is disallowed" },
+	{ "direct_write_head", "direct access to bpf_list_head is disallowed" },
+	{ "direct_read_node", "direct access to bpf_list_node is disallowed" },
+	{ "direct_write_node", "direct access to bpf_list_node is disallowed" },
+	{ "write_after_push_front", "only read is supported" },
+	{ "write_after_push_back", "only read is supported" },
+	{ "use_after_unlock_push_front", "invalid mem access 'scalar'" },
+	{ "use_after_unlock_push_back", "invalid mem access 'scalar'" },
+	{ "double_push_front", "arg#1 expected pointer to allocated object" },
+	{ "double_push_back", "arg#1 expected pointer to allocated object" },
+	{ "no_node_value_type", "bpf_list_node not found at offset=0" },
+	{ "incorrect_value_type",
+	  "operation on bpf_list_head expects arg#1 bpf_list_node at offset=0 in struct foo, "
+	  "but arg is at offset=0 in struct bar" },
+	{ "incorrect_node_var_off", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" },
+	{ "incorrect_node_off1", "bpf_list_node not found at offset=1" },
+	{ "incorrect_node_off2", "arg#1 offset=40, but expected bpf_list_node at offset=0 in struct foo" },
+	{ "no_head_type", "bpf_list_head not found at offset=0" },
+	{ "incorrect_head_var_off1", "R1 doesn't have constant offset" },
+	{ "incorrect_head_var_off2", "variable ptr_ access var_off=(0x0; 0xffffffff) disallowed" },
+	{ "incorrect_head_off1", "bpf_list_head not found at offset=17" },
+	{ "incorrect_head_off2", "bpf_list_head not found at offset=1" },
+	{ "pop_front_off",
+	  "15: (bf) r1 = r6                      ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) "
+	  "R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n"
+	  "16: (85) call bpf_this_cpu_ptr#154\nR1 type=ptr_or_null_ expected=percpu_ptr_" },
+	{ "pop_back_off",
+	  "15: (bf) r1 = r6                      ; R1_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) "
+	  "R6_w=ptr_or_null_foo(id=4,ref_obj_id=4,off=40,imm=0) refs=2,4\n"
+	  "16: (85) call bpf_this_cpu_ptr#154\nR1 type=ptr_or_null_ expected=percpu_ptr_" },
+};
+
+static void test_linked_list_fail_prog(const char *prog_name, const char *err_msg)
+{
+	LIBBPF_OPTS(bpf_object_open_opts, opts, .kernel_log_buf = log_buf,
+						.kernel_log_size = sizeof(log_buf),
+						.kernel_log_level = 1);
+	struct linked_list_fail *skel;
+	struct bpf_program *prog;
+	int ret;
+
+	skel = linked_list_fail__open_opts(&opts);
+	if (!ASSERT_OK_PTR(skel, "linked_list_fail__open_opts"))
+		return;
+
+	prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+	if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+		goto end;
+
+	bpf_program__set_autoload(prog, true);
+
+	ret = linked_list_fail__load(skel);
+	if (!ASSERT_ERR(ret, "linked_list_fail__load must fail"))
+		goto end;
+
+	if (!ASSERT_OK_PTR(strstr(log_buf, err_msg), "expected error message")) {
+		fprintf(stderr, "Expected: %s\n", err_msg);
+		fprintf(stderr, "Verifier: %s\n", log_buf);
+	}
+
+end:
+	linked_list_fail__destroy(skel);
+}
+
+static void clear_fields(struct bpf_map *map)
+{
+	char buf[24];
+	int key = 0;
+
+	memset(buf, 0xff, sizeof(buf));
+	ASSERT_OK(bpf_map__update_elem(map, &key, sizeof(key), buf, sizeof(buf), 0), "check_and_free_fields");
+}
+
+enum {
+	TEST_ALL,
+	PUSH_POP,
+	PUSH_POP_MULT,
+	LIST_IN_LIST,
+};
+
+static void test_linked_list_success(int mode, bool leave_in_map)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, opts,
+		.data_in = &pkt_v4,
+		.data_size_in = sizeof(pkt_v4),
+		.repeat = 1,
+	);
+	struct linked_list *skel;
+	int ret;
+
+	skel = linked_list__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "linked_list__open_and_load"))
+		return;
+
+	if (mode == LIST_IN_LIST)
+		goto lil;
+	if (mode == PUSH_POP_MULT)
+		goto ppm;
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_push_pop), &opts);
+	ASSERT_OK(ret, "map_list_push_pop");
+	ASSERT_OK(opts.retval, "map_list_push_pop retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.array_map);
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_push_pop), &opts);
+	ASSERT_OK(ret, "inner_map_list_push_pop");
+	ASSERT_OK(opts.retval, "inner_map_list_push_pop retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.inner_map);
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop), &opts);
+	ASSERT_OK(ret, "global_list_push_pop");
+	ASSERT_OK(opts.retval, "global_list_push_pop retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.bss_A);
+
+	if (mode == PUSH_POP)
+		goto end;
+
+ppm:
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_push_pop_multiple), &opts);
+	ASSERT_OK(ret, "map_list_push_pop_multiple");
+	ASSERT_OK(opts.retval, "map_list_push_pop_multiple retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.array_map);
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_push_pop_multiple), &opts);
+	ASSERT_OK(ret, "inner_map_list_push_pop_multiple");
+	ASSERT_OK(opts.retval, "inner_map_list_push_pop_multiple retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.inner_map);
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_push_pop_multiple), &opts);
+	ASSERT_OK(ret, "global_list_push_pop_multiple");
+	ASSERT_OK(opts.retval, "global_list_push_pop_multiple retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.bss_A);
+
+	if (mode == PUSH_POP_MULT)
+		goto end;
+
+lil:
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.map_list_in_list), &opts);
+	ASSERT_OK(ret, "map_list_in_list");
+	ASSERT_OK(opts.retval, "map_list_in_list retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.array_map);
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.inner_map_list_in_list), &opts);
+	ASSERT_OK(ret, "inner_map_list_in_list");
+	ASSERT_OK(opts.retval, "inner_map_list_in_list retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.inner_map);
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.global_list_in_list), &opts);
+	ASSERT_OK(ret, "global_list_in_list");
+	ASSERT_OK(opts.retval, "global_list_in_list retval");
+	if (!leave_in_map)
+		clear_fields(skel->maps.bss_A);
+end:
+	linked_list__destroy(skel);
+}
+
+#define SPIN_LOCK 2
+#define LIST_HEAD 3
+#define LIST_NODE 4
+
+static struct btf *init_btf(void)
+{
+	int id, lid, hid, nid;
+	struct btf *btf;
+
+	btf = btf__new_empty();
+	if (!ASSERT_OK_PTR(btf, "btf__new_empty"))
+		return NULL;
+	id = btf__add_int(btf, "int", 4, BTF_INT_SIGNED);
+	if (!ASSERT_EQ(id, 1, "btf__add_int"))
+		goto end;
+	lid = btf__add_struct(btf, "bpf_spin_lock", 4);
+	if (!ASSERT_EQ(lid, SPIN_LOCK, "btf__add_struct bpf_spin_lock"))
+		goto end;
+	hid = btf__add_struct(btf, "bpf_list_head", 16);
+	if (!ASSERT_EQ(hid, LIST_HEAD, "btf__add_struct bpf_list_head"))
+		goto end;
+	nid = btf__add_struct(btf, "bpf_list_node", 16);
+	if (!ASSERT_EQ(nid, LIST_NODE, "btf__add_struct bpf_list_node"))
+		goto end;
+	return btf;
+end:
+	btf__free(btf);
+	return NULL;
+}
+
+static void test_btf(void)
+{
+	struct btf *btf = NULL;
+	int id, err;
+
+	while (test__start_subtest("btf: too many locks")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 24);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_struct foo::a"))
+			break;
+		err = btf__add_field(btf, "b", SPIN_LOCK, 32, 0);
+		if (!ASSERT_OK(err, "btf__add_struct foo::a"))
+			break;
+		err = btf__add_field(btf, "c", LIST_HEAD, 64, 0);
+		if (!ASSERT_OK(err, "btf__add_struct foo::a"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -E2BIG, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: missing lock")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 16);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_struct foo::a"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:baz:a", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:baz:a"))
+			break;
+		id = btf__add_struct(btf, "baz", 16);
+		if (!ASSERT_EQ(id, 7, "btf__add_struct baz"))
+			break;
+		err = btf__add_field(btf, "a", LIST_NODE, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field baz::a"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -EINVAL, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: bad offset")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 36);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:b"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -EEXIST, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: missing contains:")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 24);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_HEAD, 64, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -EINVAL, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: missing struct")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 24);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_HEAD, 64, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bar:bar", 5, 1);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:bar"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -ENOENT, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: missing node")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 24);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_HEAD, 64, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:foo:c", 5, 1);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:c"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		btf__free(btf);
+		ASSERT_EQ(err, -ENOENT, "check btf");
+		break;
+	}
+
+	while (test__start_subtest("btf: node incorrect type")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 20);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bar:a", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:a"))
+			break;
+		id = btf__add_struct(btf, "bar", 4);
+		if (!ASSERT_EQ(id, 7, "btf__add_struct bar"))
+			break;
+		err = btf__add_field(btf, "a", SPIN_LOCK, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::a"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -EINVAL, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: multiple bpf_list_node with name b")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 52);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::c"))
+			break;
+		err = btf__add_field(btf, "d", SPIN_LOCK, 384, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::d"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:b"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -EINVAL, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: owning | owned AA cycle")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 36);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:foo:b", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:foo:b"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -ELOOP, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: owning | owned ABA cycle")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 36);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b"))
+			break;
+		id = btf__add_struct(btf, "bar", 36);
+		if (!ASSERT_EQ(id, 7, "btf__add_struct bar"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:foo:b", 7, 0);
+		if (!ASSERT_EQ(id, 8, "btf__add_decl_tag contains:foo:b"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -ELOOP, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: owning -> owned")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 20);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bar:a", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:a"))
+			break;
+		id = btf__add_struct(btf, "bar", 16);
+		if (!ASSERT_EQ(id, 7, "btf__add_struct bar"))
+			break;
+		err = btf__add_field(btf, "a", LIST_NODE, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::a"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, 0, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: owning -> owning | owned -> owned")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 20);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b"))
+			break;
+		id = btf__add_struct(btf, "bar", 36);
+		if (!ASSERT_EQ(id, 7, "btf__add_struct bar"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:baz:a", 7, 0);
+		if (!ASSERT_EQ(id, 8, "btf__add_decl_tag contains:baz:a"))
+			break;
+		id = btf__add_struct(btf, "baz", 16);
+		if (!ASSERT_EQ(id, 9, "btf__add_struct baz"))
+			break;
+		err = btf__add_field(btf, "a", LIST_NODE, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field baz:a"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, 0, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: owning | owned -> owning | owned -> owned")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 36);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b"))
+			break;
+		id = btf__add_struct(btf, "bar", 36);
+		if (!ASSERT_EQ(id, 7, "btf__add_struct bar"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar:a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar:b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar:c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:baz:a", 7, 0);
+		if (!ASSERT_EQ(id, 8, "btf__add_decl_tag contains:baz:a"))
+			break;
+		id = btf__add_struct(btf, "baz", 16);
+		if (!ASSERT_EQ(id, 9, "btf__add_struct baz"))
+			break;
+		err = btf__add_field(btf, "a", LIST_NODE, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field baz:a"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -ELOOP, "check btf");
+		btf__free(btf);
+		break;
+	}
+
+	while (test__start_subtest("btf: owning -> owning | owned -> owning | owned -> owned")) {
+		btf = init_btf();
+		if (!ASSERT_OK_PTR(btf, "init_btf"))
+			break;
+		id = btf__add_struct(btf, "foo", 20);
+		if (!ASSERT_EQ(id, 5, "btf__add_struct foo"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::a"))
+			break;
+		err = btf__add_field(btf, "b", SPIN_LOCK, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field foo::b"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bar:b", 5, 0);
+		if (!ASSERT_EQ(id, 6, "btf__add_decl_tag contains:bar:b"))
+			break;
+		id = btf__add_struct(btf, "bar", 36);
+		if (!ASSERT_EQ(id, 7, "btf__add_struct bar"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:baz:b", 7, 0);
+		if (!ASSERT_EQ(id, 8, "btf__add_decl_tag"))
+			break;
+		id = btf__add_struct(btf, "baz", 36);
+		if (!ASSERT_EQ(id, 9, "btf__add_struct baz"))
+			break;
+		err = btf__add_field(btf, "a", LIST_HEAD, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::a"))
+			break;
+		err = btf__add_field(btf, "b", LIST_NODE, 128, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::b"))
+			break;
+		err = btf__add_field(btf, "c", SPIN_LOCK, 256, 0);
+		if (!ASSERT_OK(err, "btf__add_field bar::c"))
+			break;
+		id = btf__add_decl_tag(btf, "contains:bam:a", 9, 0);
+		if (!ASSERT_EQ(id, 10, "btf__add_decl_tag contains:bam:a"))
+			break;
+		id = btf__add_struct(btf, "bam", 16);
+		if (!ASSERT_EQ(id, 11, "btf__add_struct bam"))
+			break;
+		err = btf__add_field(btf, "a", LIST_NODE, 0, 0);
+		if (!ASSERT_OK(err, "btf__add_field bam::a"))
+			break;
+
+		err = btf__load_into_kernel(btf);
+		ASSERT_EQ(err, -ELOOP, "check btf");
+		btf__free(btf);
+		break;
+	}
+}
+
+void test_linked_list(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(linked_list_fail_tests); i++) {
+		if (!test__start_subtest(linked_list_fail_tests[i].prog_name))
+			continue;
+		test_linked_list_fail_prog(linked_list_fail_tests[i].prog_name,
+					   linked_list_fail_tests[i].err_msg);
+	}
+	test_btf();
+	test_linked_list_success(PUSH_POP, false);
+	test_linked_list_success(PUSH_POP, true);
+	test_linked_list_success(PUSH_POP_MULT, false);
+	test_linked_list_success(PUSH_POP_MULT, true);
+	test_linked_list_success(LIST_IN_LIST, false);
+	test_linked_list_success(LIST_IN_LIST, true);
+	test_linked_list_success(TEST_ALL, false);
+}