selftests/bpf: Add BPF linked list API tests

Include various tests covering the success and failure cases. Also, run
the success cases at runtime to verify correctness of linked list
manipulation routines, in addition to ensuring successful verification.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20221118015614.2013203-23-memxor@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/DENYLIST.aarch64

@@ -38,6 +38,7 @@ kprobe_multi_test/skel_api                       # kprobe_multi__attach unexpect
 ksyms_module/libbpf                              # 'bpf_testmod_ksym_percpu': not found in kernel BTF
 ksyms_module/lskel                               # test_ksyms_module_lskel__open_and_load unexpected error: -2
 libbpf_get_fd_by_id_opts                         # test_libbpf_get_fd_by_id_opts__attach unexpected error: -524 (errno 524)
+linked_list
 lookup_key                                       # test_lookup_key__attach unexpected error: -524 (errno 524)
 lru_bug                                          # lru_bug__attach unexpected error: -524 (errno 524)
 modify_return                                    # modify_return__attach failed unexpected error: -524 (errno 524)

tools/testing/selftests/bpf/DENYLIST.s390x

@@ -33,6 +33,7 @@ ksyms_module                             # test_ksyms_module__open_and_load unex
 ksyms_module_libbpf                      # JIT does not support calling kernel function                                (kfunc)
 ksyms_module_lskel                       # test_ksyms_module_lskel__open_and_load unexpected error: -9                 (?)
 libbpf_get_fd_by_id_opts                 # failed to attach: ERROR: strerror_r(-524)=22                                (trampoline)
+linked_list				 # JIT does not support calling kernel function                                (kfunc)
 lookup_key                               # JIT does not support calling kernel function                                (kfunc)
 lru_bug                                  # prog 'printk': failed to auto-attach: -524
 map_kptr                                 # failed to open_and_load program: -524 (trampoline)

tools/testing/selftests/bpf/prog_tests/linked_list.c

+// SPDX-License-Identifier: GPL-2.0
+#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.data_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.data_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.data_A);
+end:
+	linked_list__destroy(skel);
+}
+
+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_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);
+}

tools/testing/selftests/bpf/progs/linked_list.c

+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include "bpf_experimental.h"
+
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
+#include "linked_list.h"
+
+static __always_inline
+int list_push_pop(struct bpf_spin_lock *lock, struct bpf_list_head *head, bool leave_in_map)
+{
+	struct bpf_list_node *n;
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 2;
+
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_front(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_obj_drop(container_of(n, struct foo, node));
+		bpf_obj_drop(f);
+		return 3;
+	}
+
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_back(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_obj_drop(container_of(n, struct foo, node));
+		bpf_obj_drop(f);
+		return 4;
+	}
+
+
+	bpf_spin_lock(lock);
+	f->data = 42;
+	bpf_list_push_front(head, &f->node);
+	bpf_spin_unlock(lock);
+	if (leave_in_map)
+		return 0;
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_back(head);
+	bpf_spin_unlock(lock);
+	if (!n)
+		return 5;
+	f = container_of(n, struct foo, node);
+	if (f->data != 42) {
+		bpf_obj_drop(f);
+		return 6;
+	}
+
+	bpf_spin_lock(lock);
+	f->data = 13;
+	bpf_list_push_front(head, &f->node);
+	bpf_spin_unlock(lock);
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_front(head);
+	bpf_spin_unlock(lock);
+	if (!n)
+		return 7;
+	f = container_of(n, struct foo, node);
+	if (f->data != 13) {
+		bpf_obj_drop(f);
+		return 8;
+	}
+	bpf_obj_drop(f);
+
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_front(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_obj_drop(container_of(n, struct foo, node));
+		return 9;
+	}
+
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_back(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_obj_drop(container_of(n, struct foo, node));
+		return 10;
+	}
+	return 0;
+}
+
+
+static __always_inline
+int list_push_pop_multiple(struct bpf_spin_lock *lock, struct bpf_list_head *head, bool leave_in_map)
+{
+	struct bpf_list_node *n;
+	struct foo *f[8], *pf;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(f); i++) {
+		f[i] = bpf_obj_new(typeof(**f));
+		if (!f[i])
+			return 2;
+		f[i]->data = i;
+		bpf_spin_lock(lock);
+		bpf_list_push_front(head, &f[i]->node);
+		bpf_spin_unlock(lock);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(f); i++) {
+		bpf_spin_lock(lock);
+		n = bpf_list_pop_front(head);
+		bpf_spin_unlock(lock);
+		if (!n)
+			return 3;
+		pf = container_of(n, struct foo, node);
+		if (pf->data != (ARRAY_SIZE(f) - i - 1)) {
+			bpf_obj_drop(pf);
+			return 4;
+		}
+		bpf_spin_lock(lock);
+		bpf_list_push_back(head, &pf->node);
+		bpf_spin_unlock(lock);
+	}
+
+	if (leave_in_map)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(f); i++) {
+		bpf_spin_lock(lock);
+		n = bpf_list_pop_back(head);
+		bpf_spin_unlock(lock);
+		if (!n)
+			return 5;
+		pf = container_of(n, struct foo, node);
+		if (pf->data != i) {
+			bpf_obj_drop(pf);
+			return 6;
+		}
+		bpf_obj_drop(pf);
+	}
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_back(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_obj_drop(container_of(n, struct foo, node));
+		return 7;
+	}
+
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_front(head);
+	bpf_spin_unlock(lock);
+	if (n) {
+		bpf_obj_drop(container_of(n, struct foo, node));
+		return 8;
+	}
+	return 0;
+}
+
+static __always_inline
+int list_in_list(struct bpf_spin_lock *lock, struct bpf_list_head *head, bool leave_in_map)
+{
+	struct bpf_list_node *n;
+	struct bar *ba[8], *b;
+	struct foo *f;
+	int i;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 2;
+	for (i = 0; i < ARRAY_SIZE(ba); i++) {
+		b = bpf_obj_new(typeof(*b));
+		if (!b) {
+			bpf_obj_drop(f);
+			return 3;
+		}
+		b->data = i;
+		bpf_spin_lock(&f->lock);
+		bpf_list_push_back(&f->head, &b->node);
+		bpf_spin_unlock(&f->lock);
+	}
+
+	bpf_spin_lock(lock);
+	f->data = 42;
+	bpf_list_push_front(head, &f->node);
+	bpf_spin_unlock(lock);
+
+	if (leave_in_map)
+		return 0;
+
+	bpf_spin_lock(lock);
+	n = bpf_list_pop_front(head);
+	bpf_spin_unlock(lock);
+	if (!n)
+		return 4;
+	f = container_of(n, struct foo, node);
+	if (f->data != 42) {
+		bpf_obj_drop(f);
+		return 5;
+	}
+
+	for (i = 0; i < ARRAY_SIZE(ba); i++) {
+		bpf_spin_lock(&f->lock);
+		n = bpf_list_pop_front(&f->head);
+		bpf_spin_unlock(&f->lock);
+		if (!n) {
+			bpf_obj_drop(f);
+			return 6;
+		}
+		b = container_of(n, struct bar, node);
+		if (b->data != i) {
+			bpf_obj_drop(f);
+			bpf_obj_drop(b);
+			return 7;
+		}
+		bpf_obj_drop(b);
+	}
+	bpf_spin_lock(&f->lock);
+	n = bpf_list_pop_front(&f->head);
+	bpf_spin_unlock(&f->lock);
+	if (n) {
+		bpf_obj_drop(f);
+		bpf_obj_drop(container_of(n, struct bar, node));
+		return 8;
+	}
+	bpf_obj_drop(f);
+	return 0;
+}
+
+static __always_inline
+int test_list_push_pop(struct bpf_spin_lock *lock, struct bpf_list_head *head)
+{
+	int ret;
+
+	ret = list_push_pop(lock, head, false);
+	if (ret)
+		return ret;
+	return list_push_pop(lock, head, true);
+}
+
+static __always_inline
+int test_list_push_pop_multiple(struct bpf_spin_lock *lock, struct bpf_list_head *head)
+{
+	int ret;
+
+	ret = list_push_pop_multiple(lock ,head, false);
+	if (ret)
+		return ret;
+	return list_push_pop_multiple(lock, head, true);
+}
+
+static __always_inline
+int test_list_in_list(struct bpf_spin_lock *lock, struct bpf_list_head *head)
+{
+	int ret;
+
+	ret = list_in_list(lock, head, false);
+	if (ret)
+		return ret;
+	return list_in_list(lock, head, true);
+}
+
+SEC("tc")
+int map_list_push_pop(void *ctx)
+{
+	struct map_value *v;
+
+	v = bpf_map_lookup_elem(&array_map, &(int){0});
+	if (!v)
+		return 1;
+	return test_list_push_pop(&v->lock, &v->head);
+}
+
+SEC("tc")
+int inner_map_list_push_pop(void *ctx)
+{
+	struct map_value *v;
+	void *map;
+
+	map = bpf_map_lookup_elem(&map_of_maps, &(int){0});
+	if (!map)
+		return 1;
+	v = bpf_map_lookup_elem(map, &(int){0});
+	if (!v)
+		return 1;
+	return test_list_push_pop(&v->lock, &v->head);
+}
+
+SEC("tc")
+int global_list_push_pop(void *ctx)
+{
+	return test_list_push_pop(&glock, &ghead);
+}
+
+SEC("tc")
+int map_list_push_pop_multiple(void *ctx)
+{
+	struct map_value *v;
+	int ret;
+
+	v = bpf_map_lookup_elem(&array_map, &(int){0});
+	if (!v)
+		return 1;
+	return test_list_push_pop_multiple(&v->lock, &v->head);
+}
+
+SEC("tc")
+int inner_map_list_push_pop_multiple(void *ctx)
+{
+	struct map_value *v;
+	void *map;
+	int ret;
+
+	map = bpf_map_lookup_elem(&map_of_maps, &(int){0});
+	if (!map)
+		return 1;
+	v = bpf_map_lookup_elem(map, &(int){0});
+	if (!v)
+		return 1;
+	return test_list_push_pop_multiple(&v->lock, &v->head);
+}
+
+SEC("tc")
+int global_list_push_pop_multiple(void *ctx)
+{
+	int ret;
+
+	ret = list_push_pop_multiple(&glock, &ghead, false);
+	if (ret)
+		return ret;
+	return list_push_pop_multiple(&glock, &ghead, true);
+}
+
+SEC("tc")
+int map_list_in_list(void *ctx)
+{
+	struct map_value *v;
+	int ret;
+
+	v = bpf_map_lookup_elem(&array_map, &(int){0});
+	if (!v)
+		return 1;
+	return test_list_in_list(&v->lock, &v->head);
+}
+
+SEC("tc")
+int inner_map_list_in_list(void *ctx)
+{
+	struct map_value *v;
+	void *map;
+	int ret;
+
+	map = bpf_map_lookup_elem(&map_of_maps, &(int){0});
+	if (!map)
+		return 1;
+	v = bpf_map_lookup_elem(map, &(int){0});
+	if (!v)
+		return 1;
+	return test_list_in_list(&v->lock, &v->head);
+}
+
+SEC("tc")
+int global_list_in_list(void *ctx)
+{
+	return test_list_in_list(&glock, &ghead);
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/linked_list.h

+// SPDX-License-Identifier: GPL-2.0
+#ifndef LINKED_LIST_H
+#define LINKED_LIST_H
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_experimental.h"
+
+struct bar {
+	struct bpf_list_node node;
+	int data;
+};
+
+struct foo {
+	struct bpf_list_node node;
+	struct bpf_list_head head __contains(bar, node);
+	struct bpf_spin_lock lock;
+	int data;
+	struct bpf_list_node node2;
+};
+
+struct map_value {
+	struct bpf_spin_lock lock;
+	int data;
+	struct bpf_list_head head __contains(foo, node);
+};
+
+struct array_map {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, struct map_value);
+	__uint(max_entries, 1);
+};
+
+struct array_map array_map SEC(".maps");
+struct array_map inner_map SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
+	__uint(max_entries, 1);
+	__type(key, int);
+	__type(value, int);
+	__array(values, struct array_map);
+} map_of_maps SEC(".maps") = {
+	.values = {
+		[0] = &inner_map,
+	},
+};
+
+#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
+
+private(A) struct bpf_spin_lock glock;
+private(A) struct bpf_list_head ghead __contains(foo, node);
+private(B) struct bpf_spin_lock glock2;
+
+#endif