Merge branch 'Allocated objects, BPF linked lists'

Kumar Kartikeya Dwivedi says:

====================

This series introduces user defined BPF objects of a type in program
BTF. This allows BPF programs to allocate their own objects, build their
own object hierarchies, and use the basic building blocks provided by
BPF runtime to build their own data structures flexibly.

Then, we introduce the support for single ownership BPF linked lists,
which can be put inside BPF maps, or allocated objects, and hold such
allocated objects as elements. It works as an instrusive collection,
which is done to allow making allocated objects part of multiple data
structures at the same time in the future.

The eventual goal of this and future patches is to allow one to do some
limited form of kernel style programming in BPF C, and allow programmers
to build their own complex data structures flexibly out of basic
building blocks.

The key difference will be that such programs are verified to be safe,
preserve runtime integrity of the system, and are proven to be bug free
as far as the invariants of BPF specific APIs are concerned.

One immediate use case that will be using the entire infrastructure this
series is introducing will be managing percpu NMI safe linked lists
inside BPF programs.

The other use case this will serve in the near future will be linking
kernel structures like XDP frame and sk_buff directly into user data
structures (rbtree, pifomap, etc.) for packet queueing. This will follow
single ownership concept included in this series.

The user has complete control of the internal locking, and hence also
the batching of operations for each critical section.

The features are:
- Allocated objects.
- bpf_obj_new, bpf_obj_drop to allocate and free them.
- Single ownership BPF linked lists.
- Support for them in BPF maps.
- Support for them in allocated objects.
- Global spin locks.
- Spin locks inside allocated objects.

Some other notable things:
- Completely static verification of locking.
- Kfunc argument handling has been completely reworked.
- Argument rewriting support for kfuncs.
- A new bpf_experimental.h header as a dumping ground for these APIs.

Any functionality exposed in this series is NOT part of UAPI. It is only
available through use of kfuncs, and structs that can be added to map
value may also change their size or name in the future. Hence, every
feature in this series must be considered experimental.

Follow-ups:
-----------
* Support for kptrs (local and kernel) in local storage and percpu maps + kptr tests
* Fixes for helper access checks rebasing on top of this series

Next steps:
-----------
* NMI safe percpu single ownership linked lists (using local_t protection).
* Lockless linked lists.
* Allow RCU protected BPF allocated objects. This then allows RCU
protected list lookups, since spinlock protection for readers does
not scale.
* Introduce bpf_refcount for local kptrs, shared ownership.
* Introduce shared ownership linked lists.
* Documentation.

Changelog:
----------
v9 -> v10
v9: https://lore.kernel.org/bpf/[e-mail]

* Deduplicate code to find btf_record of reg (Alexei)
* Add linked_list test to DENYLIST.aarch64 (Alexei)
* Disable some linked list tests for now so that they compile with
clang nightly (Alexei)

v8 -> v9
v8: https://lore.kernel.org/bpf/[e-mail]

* Fix up commit log of patch 2, Simplify patch 3
* Explain the implicit requirement of bpf_list_head requiring map BTF
to match in btf_record_equal in a separate patch.

v7 -> v8
v7: https://lore.kernel.org/bpf/[e-mail]

* Fix early return in map_check_btf (Dan Carpenter)
* Fix two memory leak bugs in local storage maps, outer maps
* Address comments from Alexei and Dave
* More local kptr -> allocated object renaming
* Use krealloc with NULL instead kmalloc + krealloc
* Drop WARN_ON_ONCE for field_offs parsing
* Combine kfunc add + remove patches into one
* Drop STRONG suffix from KF_ARG_PTR_TO_KPTR
* Rename is_kfunc_arg_ret_buf_size to is_kfunc_arg_scalar_with_name
* Remove redundant check for reg->type and arg type in it
* Drop void * ret type check
* Remove code duplication in checks for NULL pointer with offset != 0
* Fix two bpf_list_node typos
* Improve log message for bpf_list_head operations
* Improve comments for active_lock struct
* Improve comments for Implementation details of process_spin_lock
* Add Dave's acks

v6 -> v7
v6: https://lore.kernel.org/bpf/[e-mail]

* Fix uninitialized variable warning (Dan Carpenter, Kernel Test Robot)
* One more local_kptr renaming

v5 -> v6
v5: https://lore.kernel.org/bpf/[e-mail]

* Replace (i && !off) check with next_off, include test (Andrii)
* Drop local kptrs naming (Andrii, Alexei)
* Drop reg->precise == EXACT patch (Andrii)
* Add comment about ptr member of struct active_lock (Andrii)
* Use btf__new_empty + btf__add_xxx APIs (Andrii)
* Address other misc nits from Andrii

v4 -> v5
v4: https://lore.kernel.org/bpf/[e-mail]

* Add a lot more selftests (failure, success, runtime, BTF)
* Make sure series is bisect friendly
* Move list draining out of spin lock
* This exposed an issue where bpf_mem_free can now be called in
map_free path without migrate_disable, also fixed that.
* Rename MEM_ALLOC -> MEM_RINGBUF, MEM_TYPE_LOCAL -> MEM_ALLOC (Alexei)
* Group lock identity into a struct active_lock { ptr, id } (Dave)
* Split set_release_on_unlock logic into separate patch (Alexei)

v3 -> v4
v3: https://lore.kernel.org/bpf/[e-mail]

* Fix compiler error for !CONFIG_BPF_SYSCALL (Kernel Test Robot)
* Fix error due to BUILD_BUG_ON on 32-bit platforms (Kernel Test Robot)

v2 -> v3
v2: https://lore.kernel.org/bpf/[e-mail]

* Add ack from Dave for patch 5
* Rename btf_type_fields -> btf_record, btf_type_fields_off ->
btf_field_offs, rename functions similarly (Alexei)
* Remove 'kind' component from contains declaration tag (Alexei)
* Move bpf_list_head, bpf_list_node definitions to UAPI bpf.h (Alexei)
* Add note in commit log about modifying btf_struct_access API (Dave)
* Downgrade WARN_ON_ONCE to verbose(env, "...") and return -EFAULT (Dave)
* Add type_is_local_kptr wrapper to avoid noisy checks (Dave)
* Remove unused flags parameter from bpf_kptr_new (Alexei)
* Rename bpf_kptr_new -> bpf_obj_new, bpf_kptr_drop -> bpf_obj_drop (Alexei)
* Reword comment in ref_obj_id_set_release_on_unlock (Dave)
* Fix return type of ref_obj_id_set_release_on_unlock (Dave)
* Introduce is_bpf_list_api_kfunc to dedup checks (Dave)
* Disallow BPF_WRITE to untrusted local kptrs
* Add details about soundness of check_reg_allocation_locked logic
* List untrusted local kptrs for PROBE_MEM handling

v1 -> v2
v1: https://lore.kernel.org/bpf/[e-mail]

* Rebase on bpf-next to resolve merge conflict in DENYLIST.s390x
* Fix a couple of mental lapses in bpf_list_head_free

RFC v1 -> v1
RFC v1: https://lore.kernel.org/bpf/[e-mail]

* Mostly a complete rewrite of BTF parsing, refactor existing code (Kartikeya)
* Rebase kfunc rewrite for bpf-next, add support for more changes
* Cache type metadata in BTF to avoid recomputation inside verifier (Kartikeya)
* Remove __kernel tag, make things similar to map values, reserve bpf_ prefix
* bpf_kptr_new, bpf_kptr_drop
* Rename precision state enum values (Alexei)
* Drop explicit constructor/destructor support (Alexei)
* Rewrite code for constructing/destructing objects and offload to runtime
* Minimize duplication in bpf_map_value_off_desc handling (Alexei)
* Expose global memory allocator (Alexei)
* Address other nits from Alexei
* Split out local kptrs in maps, more kptrs in maps support into a follow up

Links:
------
* Dave's BPF RB-Tree RFC series
v1 (Discussion thread)
https://lore.kernel.org/bpf/[e-mail]
v2 (With support for static locks)
https://lore.kernel.org/bpf/[e-mail]
* BPF Linked Lists Discussion
https://lore.kernel.org/bpf/[e-mail]
* BPF Memory Allocator from Alexei
https://lore.kernel.org/bpf/[e-mail]
* BPF Memory Allocator UAPI Discussion
https://lore.kernel.org/bpf/[e-mail]
====================

Signed-off-by: Alexei Starovoitov <[e-mail]>

Documentation/bpf/kfuncs.rst

···
 of the pointer is used. Without __sz annotation, a kfunc cannot accept a void
 pointer.
 
+2.2.2 __k Annotation
+--------------------
+
+This annotation is only understood for scalar arguments, where it indicates that
+the verifier must check the scalar argument to be a known constant, which does
+not indicate a size parameter, and the value of the constant is relevant to the
+safety of the program.
+
+An example is given below::
+
+        void *bpf_obj_new(u32 local_type_id__k, ...)
+        {
+        ...
+        }
+
+Here, bpf_obj_new uses local_type_id argument to find out the size of that type
+ID in program's BTF and return a sized pointer to it. Each type ID will have a
+distinct size, hence it is crucial to treat each such call as distinct when
+values don't match during verifier state pruning checks.
+
+Hence, whenever a constant scalar argument is accepted by a kfunc which is not a
+size parameter, and the value of the constant matters for program safety, __k
+suffix should be used.
+
 .. _BPF_kfunc_nodef:
 
 2.3 Using an existing kernel function

include/linux/bpf.h

···
 extern struct idr btf_idr;
 extern spinlock_t btf_idr_lock;
 extern struct kobject *btf_kobj;
+extern struct bpf_mem_alloc bpf_global_ma;
+extern bool bpf_global_ma_set;
 
 typedef u64 (*bpf_callback_t)(u64, u64, u64, u64, u64);
 typedef int (*bpf_iter_init_seq_priv_t)(void *private_data,
···
 	BPF_KPTR_REF   = (1 << 3),
 	BPF_KPTR       = BPF_KPTR_UNREF | BPF_KPTR_REF,
 	BPF_LIST_HEAD  = (1 << 4),
+	BPF_LIST_NODE  = (1 << 5),
 };
 
 struct btf_field_kptr {
···
 	struct btf *btf;
 	u32 value_btf_id;
 	u32 node_offset;
+	struct btf_record *value_rec;
 };
 
 struct btf_field {
···
 		return "kptr";
 	case BPF_LIST_HEAD:
 		return "bpf_list_head";
+	case BPF_LIST_NODE:
+		return "bpf_list_node";
 	default:
 		WARN_ON_ONCE(1);
 		return "unknown";
···
 		return sizeof(u64);
 	case BPF_LIST_HEAD:
 		return sizeof(struct bpf_list_head);
+	case BPF_LIST_NODE:
+		return sizeof(struct bpf_list_node);
 	default:
 		WARN_ON_ONCE(1);
 		return 0;
···
 		return __alignof__(u64);
 	case BPF_LIST_HEAD:
 		return __alignof__(struct bpf_list_head);
+	case BPF_LIST_NODE:
+		return __alignof__(struct bpf_list_node);
 	default:
 		WARN_ON_ONCE(1);
 		return 0;
···
 	return rec->field_mask & type;
 }
 
+static inline void bpf_obj_init(const struct btf_field_offs *foffs, void *obj)
+{
+	int i;
+
+	if (!foffs)
+		return;
+	for (i = 0; i < foffs->cnt; i++)
+		memset(obj + foffs->field_off[i], 0, foffs->field_sz[i]);
+}
+
 static inline void check_and_init_map_value(struct bpf_map *map, void *dst)
 {
-	if (!IS_ERR_OR_NULL(map->record)) {
-		struct btf_field *fields = map->record->fields;
-		u32 cnt = map->record->cnt;
-		int i;
-
-		for (i = 0; i < cnt; i++)
-			memset(dst + fields[i].offset, 0, btf_field_type_size(fields[i].type));
-	}
+	bpf_obj_init(map->field_offs, dst);
 }
 
 /* memcpy that is used with 8-byte aligned pointers, power-of-8 size and
···
 
 	/* Size is known at compile time. */
 	MEM_FIXED_SIZE		= BIT(10 + BPF_BASE_TYPE_BITS),
+
+	/* MEM is of an allocated object of type in program BTF. This is used to
+	 * tag PTR_TO_BTF_ID allocated using bpf_obj_new.
+	 */
+	MEM_ALLOC		= BIT(11 + BPF_BASE_TYPE_BITS),
 
 	__BPF_TYPE_FLAG_MAX,
 	__BPF_TYPE_LAST_FLAG	= __BPF_TYPE_FLAG_MAX - 1,
···
 			   const char *func_name,
 			   struct btf_func_model *m);
 
-struct bpf_kfunc_arg_meta {
-	u64 r0_size;
-	bool r0_rdonly;
-	int ref_obj_id;
-	u32 flags;
-};
-
 struct bpf_reg_state;
 int btf_check_subprog_arg_match(struct bpf_verifier_env *env, int subprog,
 				struct bpf_reg_state *regs);
 int btf_check_subprog_call(struct bpf_verifier_env *env, int subprog,
 			   struct bpf_reg_state *regs);
-int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
-			      const struct btf *btf, u32 func_id,
-			      struct bpf_reg_state *regs,
-			      struct bpf_kfunc_arg_meta *meta);
 int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog,
 			  struct bpf_reg_state *reg);
 int btf_check_type_match(struct bpf_verifier_log *log, const struct bpf_prog *prog,
···
 	bool has_ref;
 };
 #endif /* CONFIG_KEYS */
+
+static inline bool type_is_alloc(u32 type)
+{
+	return type & MEM_ALLOC;
+}
+
 #endif /* _LINUX_BPF_H */

include/linux/bpf_verifier.h

···
 	 * exiting a callback function.
 	 */
 	int callback_ref;
+	/* Mark the reference state to release the registers sharing the same id
+	 * on bpf_spin_unlock (for nodes that we will lose ownership to but are
+	 * safe to access inside the critical section).
+	 */
+	bool release_on_unlock;
 };
 
 /* state of the program:
···
 	u32 branches;
 	u32 insn_idx;
 	u32 curframe;
-	u32 active_spin_lock;
+	/* For every reg representing a map value or allocated object pointer,
+	 * we consider the tuple of (ptr, id) for them to be unique in verifier
+	 * context and conside them to not alias each other for the purposes of
+	 * tracking lock state.
+	 */
+	struct {
+		/* This can either be reg->map_ptr or reg->btf. If ptr is NULL,
+		 * there's no active lock held, and other fields have no
+		 * meaning. If non-NULL, it indicates that a lock is held and
+		 * id member has the reg->id of the register which can be >= 0.
+		 */
+		void *ptr;
+		/* This will be reg->id */
+		u32 id;
+	} active_lock;
 	bool speculative;
 
 	/* first and last insn idx of this verifier state */
···
 		 */
 		struct bpf_loop_inline_state loop_inline_state;
 	};
+	u64 obj_new_size; /* remember the size of type passed to bpf_obj_new to rewrite R1 */
+	struct btf_struct_meta *kptr_struct_meta;
 	u64 map_key_state; /* constant (32 bit) key tracking for maps */
 	int ctx_field_size; /* the ctx field size for load insn, maybe 0 */
 	u32 seen; /* this insn was processed by the verifier at env->pass_cnt */
···
 int check_func_arg_reg_off(struct bpf_verifier_env *env,
 			   const struct bpf_reg_state *reg, int regno,
 			   enum bpf_arg_type arg_type);
-int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
-			     u32 regno);
 int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
 		   u32 regno, u32 mem_size);
 bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env,

include/linux/btf.h

···
 
 #include <linux/types.h>
 #include <linux/bpfptr.h>
+#include <linux/bsearch.h>
+#include <linux/btf_ids.h>
 #include <uapi/linux/btf.h>
 #include <uapi/linux/bpf.h>
 
···
 struct btf_id_dtor_kfunc {
 	u32 btf_id;
 	u32 kfunc_btf_id;
+};
+
+struct btf_struct_meta {
+	u32 btf_id;
+	struct btf_record *record;
+	struct btf_field_offs *field_offs;
+};
+
+struct btf_struct_metas {
+	u32 cnt;
+	struct btf_struct_meta types[];
 };
 
 typedef void (*btf_dtor_kfunc_t)(void *);
···
 int btf_find_timer(const struct btf *btf, const struct btf_type *t);
 struct btf_record *btf_parse_fields(const struct btf *btf, const struct btf_type *t,
 				    u32 field_mask, u32 value_size);
+int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec);
 struct btf_field_offs *btf_parse_field_offs(struct btf_record *rec);
 bool btf_type_is_void(const struct btf_type *t);
 s32 btf_find_by_name_kind(const struct btf *btf, const char *name, u8 kind);
···
 	return kind == BTF_KIND_STRUCT || kind == BTF_KIND_UNION;
 }
 
+static inline bool __btf_type_is_struct(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
+}
+
+static inline bool btf_type_is_array(const struct btf_type *t)
+{
+	return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
+}
+
 static inline u16 btf_type_vlen(const struct btf_type *t)
 {
 	return BTF_INFO_VLEN(t->info);
···
 	return (struct btf_param *)(t + 1);
 }
 
-#ifdef CONFIG_BPF_SYSCALL
-struct bpf_prog;
+static inline int btf_id_cmp_func(const void *a, const void *b)
+{
+	const int *pa = a, *pb = b;
 
+	return *pa - *pb;
+}
+
+static inline bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
+{
+	return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
+}
+
+static inline void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
+{
+	return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
+}
+
+struct bpf_prog;
+struct bpf_verifier_log;
+
+#ifdef CONFIG_BPF_SYSCALL
 const struct btf_type *btf_type_by_id(const struct btf *btf, u32 type_id);
 const char *btf_name_by_offset(const struct btf *btf, u32 offset);
 struct btf *btf_parse_vmlinux(void);
···
 s32 btf_find_dtor_kfunc(struct btf *btf, u32 btf_id);
 int register_btf_id_dtor_kfuncs(const struct btf_id_dtor_kfunc *dtors, u32 add_cnt,
 				struct module *owner);
+struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id);
+const struct btf_member *
+btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+		      const struct btf_type *t, enum bpf_prog_type prog_type,
+		      int arg);
+bool btf_types_are_same(const struct btf *btf1, u32 id1,
+			const struct btf *btf2, u32 id2);
 #else
 static inline const struct btf_type *btf_type_by_id(const struct btf *btf,
 						    u32 type_id)
···
 					      u32 add_cnt, struct module *owner)
 {
 	return 0;
+}
+static inline struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
+{
+	return NULL;
+}
+static inline const struct btf_member *
+btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
+		      const struct btf_type *t, enum bpf_prog_type prog_type,
+		      int arg)
+{
+	return NULL;
+}
+static inline bool btf_types_are_same(const struct btf *btf1, u32 id1,
+				      const struct btf *btf2, u32 id2)
+{
+	return false;
 }
 #endif
 

kernel/bpf/arraymap.c

···
 			for (i = 0; i < array->map.max_entries; i++)
 				bpf_obj_free_fields(map->record, array_map_elem_ptr(array, i));
 		}
-		bpf_map_free_record(map);
 	}
 
 	if (array->map.map_type == BPF_MAP_TYPE_PERCPU_ARRAY)

kernel/bpf/btf.c

···
 	struct rcu_head rcu;
 	struct btf_kfunc_set_tab *kfunc_set_tab;
 	struct btf_id_dtor_kfunc_tab *dtor_kfunc_tab;
+	struct btf_struct_metas *struct_meta_tab;
 
 	/* split BTF support */
 	struct btf *base_btf;
···
 static bool btf_type_nosize_or_null(const struct btf_type *t)
 {
 	return !t || btf_type_nosize(t);
-}
-
-static bool __btf_type_is_struct(const struct btf_type *t)
-{
-	return BTF_INFO_KIND(t->info) == BTF_KIND_STRUCT;
-}
-
-static bool btf_type_is_array(const struct btf_type *t)
-{
-	return BTF_INFO_KIND(t->info) == BTF_KIND_ARRAY;
 }
 
 static bool btf_type_is_datasec(const struct btf_type *t)
···
 	btf->dtor_kfunc_tab = NULL;
 }
 
+static void btf_struct_metas_free(struct btf_struct_metas *tab)
+{
+	int i;
+
+	if (!tab)
+		return;
+	for (i = 0; i < tab->cnt; i++) {
+		btf_record_free(tab->types[i].record);
+		kfree(tab->types[i].field_offs);
+	}
+	kfree(tab);
+}
+
+static void btf_free_struct_meta_tab(struct btf *btf)
+{
+	struct btf_struct_metas *tab = btf->struct_meta_tab;
+
+	btf_struct_metas_free(tab);
+	btf->struct_meta_tab = NULL;
+}
+
 static void btf_free(struct btf *btf)
 {
+	btf_free_struct_meta_tab(btf);
 	btf_free_dtor_kfunc_tab(btf);
 	btf_free_kfunc_set_tab(btf);
 	kvfree(btf->types);
···
 			goto end;
 		}
 	}
+	if (field_mask & BPF_LIST_NODE) {
+		if (!strcmp(name, "bpf_list_node")) {
+			type = BPF_LIST_NODE;
+			goto end;
+		}
+	}
 	/* Only return BPF_KPTR when all other types with matchable names fail */
 	if (field_mask & BPF_KPTR) {
 		type = BPF_KPTR_REF;
···
 		switch (field_type) {
 		case BPF_SPIN_LOCK:
 		case BPF_TIMER:
+		case BPF_LIST_NODE:
 			ret = btf_find_struct(btf, member_type, off, sz, field_type,
 					      idx < info_cnt ? &info[idx] : &tmp);
 			if (ret < 0)
···
 		switch (field_type) {
 		case BPF_SPIN_LOCK:
 		case BPF_TIMER:
+		case BPF_LIST_NODE:
 			ret = btf_find_struct(btf, var_type, off, sz, field_type,
 					      idx < info_cnt ? &info[idx] : &tmp);
 			if (ret < 0)
···
 		return NULL;
 
 	cnt = ret;
+	/* This needs to be kzalloc to zero out padding and unused fields, see
+	 * comment in btf_record_equal.
+	 */
 	rec = kzalloc(offsetof(struct btf_record, fields[cnt]), GFP_KERNEL | __GFP_NOWARN);
 	if (!rec)
 		return ERR_PTR(-ENOMEM);
···
 			if (ret < 0)
 				goto end;
 			break;
+		case BPF_LIST_NODE:
+			break;
 		default:
 			ret = -EFAULT;
 			goto end;
···
 end:
 	btf_record_free(rec);
 	return ERR_PTR(ret);
+}
+
+int btf_check_and_fixup_fields(const struct btf *btf, struct btf_record *rec)
+{
+	int i;
+
+	/* There are two owning types, kptr_ref and bpf_list_head. The former
+	 * only supports storing kernel types, which can never store references
+	 * to program allocated local types, atleast not yet. Hence we only need
+	 * to ensure that bpf_list_head ownership does not form cycles.
+	 */
+	if (IS_ERR_OR_NULL(rec) || !(rec->field_mask & BPF_LIST_HEAD))
+		return 0;
+	for (i = 0; i < rec->cnt; i++) {
+		struct btf_struct_meta *meta;
+		u32 btf_id;
+
+		if (!(rec->fields[i].type & BPF_LIST_HEAD))
+			continue;
+		btf_id = rec->fields[i].list_head.value_btf_id;
+		meta = btf_find_struct_meta(btf, btf_id);
+		if (!meta)
+			return -EFAULT;
+		rec->fields[i].list_head.value_rec = meta->record;
+
+		if (!(rec->field_mask & BPF_LIST_NODE))
+			continue;
+
+		/* We need to ensure ownership acyclicity among all types. The
+		 * proper way to do it would be to topologically sort all BTF
+		 * IDs based on the ownership edges, since there can be multiple
+		 * bpf_list_head in a type. Instead, we use the following
+		 * reasoning:
+		 *
+		 * - A type can only be owned by another type in user BTF if it
+		 *   has a bpf_list_node.
+		 * - A type can only _own_ another type in user BTF if it has a
+		 *   bpf_list_head.
+		 *
+		 * We ensure that if a type has both bpf_list_head and
+		 * bpf_list_node, its element types cannot be owning types.
+		 *
+		 * To ensure acyclicity:
+		 *
+		 * When A only has bpf_list_head, ownership chain can be:
+		 *	A -> B -> C
+		 * Where:
+		 * - B has both bpf_list_head and bpf_list_node.
+		 * - C only has bpf_list_node.
+		 *
+		 * When A has both bpf_list_head and bpf_list_node, some other
+		 * type already owns it in the BTF domain, hence it can not own
+		 * another owning type through any of the bpf_list_head edges.
+		 *	A -> B
+		 * Where:
+		 * - B only has bpf_list_node.
+		 */
+		if (meta->record->field_mask & BPF_LIST_HEAD)
+			return -ELOOP;
+	}
+	return 0;
 }
 
 static int btf_field_offs_cmp(const void *_a, const void *_b, const void *priv)
···
 	return btf_check_sec_info(env, btf_data_size);
 }
 
+static const char *alloc_obj_fields[] = {
+	"bpf_spin_lock",
+	"bpf_list_head",
+	"bpf_list_node",
+};
+
+static struct btf_struct_metas *
+btf_parse_struct_metas(struct bpf_verifier_log *log, struct btf *btf)
+{
+	union {
+		struct btf_id_set set;
+		struct {
+			u32 _cnt;
+			u32 _ids[ARRAY_SIZE(alloc_obj_fields)];
+		} _arr;
+	} aof;
+	struct btf_struct_metas *tab = NULL;
+	int i, n, id, ret;
+
+	BUILD_BUG_ON(offsetof(struct btf_id_set, cnt) != 0);
+	BUILD_BUG_ON(sizeof(struct btf_id_set) != sizeof(u32));
+
+	memset(&aof, 0, sizeof(aof));
+	for (i = 0; i < ARRAY_SIZE(alloc_obj_fields); i++) {
+		/* Try to find whether this special type exists in user BTF, and
+		 * if so remember its ID so we can easily find it among members
+		 * of structs that we iterate in the next loop.
+		 */
+		id = btf_find_by_name_kind(btf, alloc_obj_fields[i], BTF_KIND_STRUCT);
+		if (id < 0)
+			continue;
+		aof.set.ids[aof.set.cnt++] = id;
+	}
+
+	if (!aof.set.cnt)
+		return NULL;
+	sort(&aof.set.ids, aof.set.cnt, sizeof(aof.set.ids[0]), btf_id_cmp_func, NULL);
+
+	n = btf_nr_types(btf);
+	for (i = 1; i < n; i++) {
+		struct btf_struct_metas *new_tab;
+		const struct btf_member *member;
+		struct btf_field_offs *foffs;
+		struct btf_struct_meta *type;
+		struct btf_record *record;
+		const struct btf_type *t;
+		int j, tab_cnt;
+
+		t = btf_type_by_id(btf, i);
+		if (!t) {
+			ret = -EINVAL;
+			goto free;
+		}
+		if (!__btf_type_is_struct(t))
+			continue;
+
+		cond_resched();
+
+		for_each_member(j, t, member) {
+			if (btf_id_set_contains(&aof.set, member->type))
+				goto parse;
+		}
+		continue;
+	parse:
+		tab_cnt = tab ? tab->cnt : 0;
+		new_tab = krealloc(tab, offsetof(struct btf_struct_metas, types[tab_cnt + 1]),
+				   GFP_KERNEL | __GFP_NOWARN);
+		if (!new_tab) {
+			ret = -ENOMEM;
+			goto free;
+		}
+		if (!tab)
+			new_tab->cnt = 0;
+		tab = new_tab;
+
+		type = &tab->types[tab->cnt];
+		type->btf_id = i;
+		record = btf_parse_fields(btf, t, BPF_SPIN_LOCK | BPF_LIST_HEAD | BPF_LIST_NODE, t->size);
+		/* The record cannot be unset, treat it as an error if so */
+		if (IS_ERR_OR_NULL(record)) {
+			ret = PTR_ERR_OR_ZERO(record) ?: -EFAULT;
+			goto free;
+		}
+		foffs = btf_parse_field_offs(record);
+		/* We need the field_offs to be valid for a valid record,
+		 * either both should be set or both should be unset.
+		 */
+		if (IS_ERR_OR_NULL(foffs)) {
+			btf_record_free(record);
+			ret = -EFAULT;
+			goto free;
+		}
+		type->record = record;
+		type->field_offs = foffs;
+		tab->cnt++;
+	}
+	return tab;
+free:
+	btf_struct_metas_free(tab);
+	return ERR_PTR(ret);
+}
+
+struct btf_struct_meta *btf_find_struct_meta(const struct btf *btf, u32 btf_id)
+{
+	struct btf_struct_metas *tab;
+
+	BUILD_BUG_ON(offsetof(struct btf_struct_meta, btf_id) != 0);
+	tab = btf->struct_meta_tab;
+	if (!tab)
+		return NULL;
+	return bsearch(&btf_id, tab->types, tab->cnt, sizeof(tab->types[0]), btf_id_cmp_func);
+}
+
 static int btf_check_type_tags(struct btf_verifier_env *env,
 			       struct btf *btf, int start_id)
 {
···
 static struct btf *btf_parse(bpfptr_t btf_data, u32 btf_data_size,
 			     u32 log_level, char __user *log_ubuf, u32 log_size)
 {
+	struct btf_struct_metas *struct_meta_tab;
 	struct btf_verifier_env *env = NULL;
 	struct bpf_verifier_log *log;
 	struct btf *btf = NULL;
···
 	if (err)
 		goto errout;
 
+	struct_meta_tab = btf_parse_struct_metas(log, btf);
+	if (IS_ERR(struct_meta_tab)) {
+		err = PTR_ERR(struct_meta_tab);
+		goto errout;
+	}
+	btf->struct_meta_tab = struct_meta_tab;
+
+	if (struct_meta_tab) {
+		int i;
+
+		for (i = 0; i < struct_meta_tab->cnt; i++) {
+			err = btf_check_and_fixup_fields(btf, struct_meta_tab->types[i].record);
+			if (err < 0)
+				goto errout_meta;
+		}
+	}
+
 	if (log->level && bpf_verifier_log_full(log)) {
 		err = -ENOSPC;
-		goto errout;
+		goto errout_meta;
 	}
 
 	btf_verifier_env_free(env);
 	refcount_set(&btf->refcnt, 1);
 	return btf;
 
+errout_meta:
+	btf_free_struct_meta_tab(btf);
 errout:
 	btf_verifier_env_free(env);
 	if (btf)
···
 #undef BPF_MAP_TYPE
 #undef BPF_LINK_TYPE
 
-static const struct btf_member *
+const struct btf_member *
 btf_get_prog_ctx_type(struct bpf_verifier_log *log, const struct btf *btf,
 		      const struct btf_type *t, enum bpf_prog_type prog_type,
 		      int arg)
···
 	u32 id = reg->btf_id;
 	int err;
 
+	while (type_is_alloc(reg->type)) {
+		struct btf_struct_meta *meta;
+		struct btf_record *rec;
+		int i;
+
+		meta = btf_find_struct_meta(btf, id);
+		if (!meta)
+			break;
+		rec = meta->record;
+		for (i = 0; i < rec->cnt; i++) {
+			struct btf_field *field = &rec->fields[i];
+			u32 offset = field->offset;
+			if (off < offset + btf_field_type_size(field->type) && offset < off + size) {
+				bpf_log(log,
+					"direct access to %s is disallowed\n",
+					btf_field_type_name(field->type));
+				return -EACCES;
+			}
+		}
+		break;
+	}
+
 	t = btf_type_by_id(btf, id);
 	do {
 		err = btf_struct_walk(log, btf, t, off, size, &id, &tmp_flag);
 
 		switch (err) {
 		case WALK_PTR:
+			/* For local types, the destination register cannot
+			 * become a pointer again.
+			 */
+			if (type_is_alloc(reg->type))
+				return SCALAR_VALUE;
 			/* If we found the pointer or scalar on t+off,
 			 * we're done.
 			 */
···
  * end up with two different module BTFs, but IDs point to the common type in
  * vmlinux BTF.
  */
-static bool btf_types_are_same(const struct btf *btf1, u32 id1,
-			       const struct btf *btf2, u32 id2)
+bool btf_types_are_same(const struct btf *btf1, u32 id1,
+			const struct btf *btf2, u32 id2)
 {
 	if (id1 != id2)
 		return false;
···
 	return btf_check_func_type_match(log, btf1, t1, btf2, t2);
 }
 
-static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
-#ifdef CONFIG_NET
-	[PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
-	[PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
-	[PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
-#endif
-};
-
-/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
-static bool __btf_type_is_scalar_struct(struct bpf_verifier_log *log,
-					const struct btf *btf,
-					const struct btf_type *t, int rec)
-{
-	const struct btf_type *member_type;
-	const struct btf_member *member;
-	u32 i;
-
-	if (!btf_type_is_struct(t))
-		return false;
-
-	for_each_member(i, t, member) {
-		const struct btf_array *array;
-
-		member_type = btf_type_skip_modifiers(btf, member->type, NULL);
-		if (btf_type_is_struct(member_type)) {
-			if (rec >= 3) {
-				bpf_log(log, "max struct nesting depth exceeded\n");
-				return false;
-			}
-			if (!__btf_type_is_scalar_struct(log, btf, member_type, rec + 1))
-				return false;
-			continue;
-		}
-		if (btf_type_is_array(member_type)) {
-			array = btf_type_array(member_type);
-			if (!array->nelems)
-				return false;
-			member_type = btf_type_skip_modifiers(btf, array->type, NULL);
-			if (!btf_type_is_scalar(member_type))
-				return false;
-			continue;
-		}
-		if (!btf_type_is_scalar(member_type))
-			return false;
-	}
-	return true;
-}
-
-static bool is_kfunc_arg_mem_size(const struct btf *btf,
-				  const struct btf_param *arg,
-				  const struct bpf_reg_state *reg)
-{
-	int len, sfx_len = sizeof("__sz") - 1;
-	const struct btf_type *t;
-	const char *param_name;
-
-	t = btf_type_skip_modifiers(btf, arg->type, NULL);
-	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
-		return false;
-
-	/* In the future, this can be ported to use BTF tagging */
-	param_name = btf_name_by_offset(btf, arg->name_off);
-	if (str_is_empty(param_name))
-		return false;
-	len = strlen(param_name);
-	if (len < sfx_len)
-		return false;
-	param_name += len - sfx_len;
-	if (strncmp(param_name, "__sz", sfx_len))
-		return false;
-
-	return true;
-}
-
-static bool btf_is_kfunc_arg_mem_size(const struct btf *btf,
-				      const struct btf_param *arg,
-				      const struct bpf_reg_state *reg,
-				      const char *name)
-{
-	int len, target_len = strlen(name);
-	const struct btf_type *t;
-	const char *param_name;
-
-	t = btf_type_skip_modifiers(btf, arg->type, NULL);
-	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
-		return false;
-
-	param_name = btf_name_by_offset(btf, arg->name_off);
-	if (str_is_empty(param_name))
-		return false;
-	len = strlen(param_name);
-	if (len != target_len)
-		return false;
-	if (strcmp(param_name, name))
-		return false;
-
-	return true;
-}
-
 static int btf_check_func_arg_match(struct bpf_verifier_env *env,
 				    const struct btf *btf, u32 func_id,
 				    struct bpf_reg_state *regs,
 				    bool ptr_to_mem_ok,
-				    struct bpf_kfunc_arg_meta *kfunc_meta,
 				    bool processing_call)
 {
 	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
-	bool rel = false, kptr_get = false, trusted_args = false;
-	bool sleepable = false;
 	struct bpf_verifier_log *log = &env->log;
-	u32 i, nargs, ref_id, ref_obj_id = 0;
-	bool is_kfunc = btf_is_kernel(btf);
 	const char *func_name, *ref_tname;
 	const struct btf_type *t, *ref_t;
 	const struct btf_param *args;
-	int ref_regno = 0, ret;
+	u32 i, nargs, ref_id;
+	int ret;
 
 	t = btf_type_by_id(btf, func_id);
 	if (!t || !btf_type_is_func(t)) {
···
 		return -EINVAL;
 	}
 
-	if (is_kfunc && kfunc_meta) {
-		/* Only kfunc can be release func */
-		rel = kfunc_meta->flags & KF_RELEASE;
-		kptr_get = kfunc_meta->flags & KF_KPTR_GET;
-		trusted_args = kfunc_meta->flags & KF_TRUSTED_ARGS;
-		sleepable = kfunc_meta->flags & KF_SLEEPABLE;
-	}
-
 	/* check that BTF function arguments match actual types that the
 	 * verifier sees.
 	 */
···
 		enum bpf_arg_type arg_type = ARG_DONTCARE;
 		u32 regno = i + 1;
 		struct bpf_reg_state *reg = &regs[regno];
-		bool obj_ptr = false;
 
 		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
 		if (btf_type_is_scalar(t)) {
-			if (is_kfunc && kfunc_meta) {
-				bool is_buf_size = false;
-
-				/* check for any const scalar parameter of name "rdonly_buf_size"
-				 * or "rdwr_buf_size"
-				 */
-				if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
-							      "rdonly_buf_size")) {
-					kfunc_meta->r0_rdonly = true;
-					is_buf_size = true;
-				} else if (btf_is_kfunc_arg_mem_size(btf, &args[i], reg,
-								     "rdwr_buf_size"))
-					is_buf_size = true;
-
-				if (is_buf_size) {
-					if (kfunc_meta->r0_size) {
-						bpf_log(log, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
-						return -EINVAL;
-					}
-
-					if (!tnum_is_const(reg->var_off)) {
-						bpf_log(log, "R%d is not a const\n", regno);
-						return -EINVAL;
-					}
-
-					kfunc_meta->r0_size = reg->var_off.value;
-					ret = mark_chain_precision(env, regno);
-					if (ret)
-						return ret;
-				}
-			}
-
 			if (reg->type == SCALAR_VALUE)
 				continue;
 			bpf_log(log, "R%d is not a scalar\n", regno);
···
 			return -EINVAL;
 		}
 
-		/* These register types have special constraints wrt ref_obj_id
-		 * and offset checks. The rest of trusted args don't.
-		 */
-		obj_ptr = reg->type == PTR_TO_CTX || reg->type == PTR_TO_BTF_ID ||
-			  reg2btf_ids[base_type(reg->type)];
-
-		/* Check if argument must be a referenced pointer, args + i has
-		 * been verified to be a pointer (after skipping modifiers).
-		 * PTR_TO_CTX is ok without having non-zero ref_obj_id.
-		 */
-		if (is_kfunc && trusted_args && (obj_ptr && reg->type != PTR_TO_CTX) && !reg->ref_obj_id) {
-			bpf_log(log, "R%d must be referenced\n", regno);
-			return -EINVAL;
-		}
-
 		ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
 		ref_tname = btf_name_by_offset(btf, ref_t->name_off);
 
-		/* Trusted args have the same offset checks as release arguments */
-		if ((trusted_args && obj_ptr) || (rel && reg->ref_obj_id))
-			arg_type |= OBJ_RELEASE;
 		ret = check_func_arg_reg_off(env, reg, regno, arg_type);
 		if (ret < 0)
 			return ret;
 
-		if (is_kfunc && reg->ref_obj_id) {
-			/* Ensure only one argument is referenced PTR_TO_BTF_ID */
-			if (ref_obj_id) {
-				bpf_log(log, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
-					regno, reg->ref_obj_id, ref_obj_id);
-				return -EFAULT;
-			}
-			ref_regno = regno;
-			ref_obj_id = reg->ref_obj_id;
-		}
-
-		/* kptr_get is only true for kfunc */
-		if (i == 0 && kptr_get) {
-			struct btf_field *kptr_field;
-
-			if (reg->type != PTR_TO_MAP_VALUE) {
-				bpf_log(log, "arg#0 expected pointer to map value\n");
-				return -EINVAL;
-			}
-
-			/* check_func_arg_reg_off allows var_off for
-			 * PTR_TO_MAP_VALUE, but we need fixed offset to find
-			 * off_desc.
-			 */
-			if (!tnum_is_const(reg->var_off)) {
-				bpf_log(log, "arg#0 must have constant offset\n");
-				return -EINVAL;
-			}
-
-			kptr_field = btf_record_find(reg->map_ptr->record, reg->off + reg->var_off.value, BPF_KPTR);
-			if (!kptr_field || kptr_field->type != BPF_KPTR_REF) {
-				bpf_log(log, "arg#0 no referenced kptr at map value offset=%llu\n",
-					reg->off + reg->var_off.value);
-				return -EINVAL;
-			}
-
-			if (!btf_type_is_ptr(ref_t)) {
-				bpf_log(log, "arg#0 BTF type must be a double pointer\n");
-				return -EINVAL;
-			}
-
-			ref_t = btf_type_skip_modifiers(btf, ref_t->type, &ref_id);
-			ref_tname = btf_name_by_offset(btf, ref_t->name_off);
-
-			if (!btf_type_is_struct(ref_t)) {
-				bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
-					func_name, i, btf_type_str(ref_t), ref_tname);
-				return -EINVAL;
-			}
-			if (!btf_struct_ids_match(log, btf, ref_id, 0, kptr_field->kptr.btf,
-						  kptr_field->kptr.btf_id, true)) {
-				bpf_log(log, "kernel function %s args#%d expected pointer to %s %s\n",
-					func_name, i, btf_type_str(ref_t), ref_tname);
-				return -EINVAL;
-			}
-			/* rest of the arguments can be anything, like normal kfunc */
-		} else if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
+		if (btf_get_prog_ctx_type(log, btf, t, prog_type, i)) {
 			/* If function expects ctx type in BTF check that caller
 			 * is passing PTR_TO_CTX.
 			 */
···
 					i, btf_type_str(t));
 				return -EINVAL;
 			}
-		} else if (is_kfunc && (reg->type == PTR_TO_BTF_ID ||
-			   (reg2btf_ids[base_type(reg->type)] && !type_flag(reg->type)))) {
-			const struct btf_type *reg_ref_t;
-			const struct btf *reg_btf;
-			const char *reg_ref_tname;
-			u32 reg_ref_id;
-
-			if (!btf_type_is_struct(ref_t)) {
-				bpf_log(log, "kernel function %s args#%d pointer type %s %s is not supported\n",
-					func_name, i, btf_type_str(ref_t),
-					ref_tname);
-				return -EINVAL;
-			}
-
-			if (reg->type == PTR_TO_BTF_ID) {
-				reg_btf = reg->btf;
-				reg_ref_id = reg->btf_id;
-			} else {
-				reg_btf = btf_vmlinux;
-				reg_ref_id = *reg2btf_ids[base_type(reg->type)];
-			}
-
-			reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id,
-							    &reg_ref_id);
-			reg_ref_tname = btf_name_by_offset(reg_btf,
-							   reg_ref_t->name_off);
-			if (!btf_struct_ids_match(log, reg_btf, reg_ref_id,
-						  reg->off, btf, ref_id,
-						  trusted_args || (rel && reg->ref_obj_id))) {
-				bpf_log(log, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
-					func_name, i,
-					btf_type_str(ref_t), ref_tname,
-					regno, btf_type_str(reg_ref_t),
-					reg_ref_tname);
-				return -EINVAL;
-			}
 		} else if (ptr_to_mem_ok && processing_call) {
 			const struct btf_type *resolve_ret;
 			u32 type_size;
-
-			if (is_kfunc) {
-				bool arg_mem_size = i + 1 < nargs && is_kfunc_arg_mem_size(btf, &args[i + 1], &regs[regno + 1]);
-				bool arg_dynptr = btf_type_is_struct(ref_t) &&
-						  !strcmp(ref_tname,
-							  stringify_struct(bpf_dynptr_kern));
-
-				/* Permit pointer to mem, but only when argument
-				 * type is pointer to scalar, or struct composed
-				 * (recursively) of scalars.
-				 * When arg_mem_size is true, the pointer can be
-				 * void *.
-				 * Also permit initialized local dynamic pointers.
-				 */
-				if (!btf_type_is_scalar(ref_t) &&
-				    !__btf_type_is_scalar_struct(log, btf, ref_t, 0) &&
-				    !arg_dynptr &&
-				    (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
-					bpf_log(log,
-						"arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
-						i, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
-					return -EINVAL;
-				}
-
-				if (arg_dynptr) {
-					if (reg->type != PTR_TO_STACK) {
-						bpf_log(log, "arg#%d pointer type %s %s not to stack\n",
-							i, btf_type_str(ref_t),
-							ref_tname);
-						return -EINVAL;
-					}
-
-					if (!is_dynptr_reg_valid_init(env, reg)) {
-						bpf_log(log,
-							"arg#%d pointer type %s %s must be valid and initialized\n",
-							i, btf_type_str(ref_t),
-							ref_tname);
-						return -EINVAL;
-					}
-
-					if (!is_dynptr_type_expected(env, reg,
-							ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) {
-						bpf_log(log,
-							"arg#%d pointer type %s %s points to unsupported dynamic pointer type\n",
-							i, btf_type_str(ref_t),
-							ref_tname);
-						return -EINVAL;
-					}
-
-					continue;
-				}
-
-				/* Check for mem, len pair */
-				if (arg_mem_size) {
-					if (check_kfunc_mem_size_reg(env, &regs[regno + 1], regno + 1)) {
-						bpf_log(log, "arg#%d arg#%d memory, len pair leads to invalid memory access\n",
-							i, i + 1);
-						return -EINVAL;
-					}
-					i++;
-					continue;
-				}
-			}
 
 			resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
 			if (IS_ERR(resolve_ret)) {
···
 			if (check_mem_reg(env, reg, regno, type_size))
 				return -EINVAL;
 		} else {
-			bpf_log(log, "reg type unsupported for arg#%d %sfunction %s#%d\n", i,
-				is_kfunc ? "kernel " : "", func_name, func_id);
+			bpf_log(log, "reg type unsupported for arg#%d function %s#%d\n", i,
+				func_name, func_id);
 			return -EINVAL;
 		}
 	}
 
-	/* Either both are set, or neither */
-	WARN_ON_ONCE((ref_obj_id && !ref_regno) || (!ref_obj_id && ref_regno));
-	/* We already made sure ref_obj_id is set only for one argument. We do
-	 * allow (!rel && ref_obj_id), so that passing such referenced
-	 * PTR_TO_BTF_ID to other kfuncs works. Note that rel is only true when
-	 * is_kfunc is true.
-	 */
-	if (rel && !ref_obj_id) {
-		bpf_log(log, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
-			func_name);
-		return -EINVAL;
-	}
-
-	if (sleepable && !env->prog->aux->sleepable) {
-		bpf_log(log, "kernel function %s is sleepable but the program is not\n",
-			func_name);
-		return -EINVAL;
-	}
-
-	if (kfunc_meta && ref_obj_id)
-		kfunc_meta->ref_obj_id = ref_obj_id;
-
-	/* returns argument register number > 0 in case of reference release kfunc */
-	return rel ? ref_regno : 0;
+	return 0;
 }
 
 /* Compare BTF of a function declaration with given bpf_reg_state.
···
 		return -EINVAL;
 
 	is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
-	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, false);
+	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, false);
 
 	/* Compiler optimizations can remove arguments from static functions
 	 * or mismatched type can be passed into a global function.
···
 		return -EINVAL;
 
 	is_global = prog->aux->func_info_aux[subprog].linkage == BTF_FUNC_GLOBAL;
-	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, NULL, true);
+	err = btf_check_func_arg_match(env, btf, btf_id, regs, is_global, true);
 
 	/* Compiler optimizations can remove arguments from static functions
 	 * or mismatched type can be passed into a global function.
···
 	if (err)
 		prog->aux->func_info_aux[subprog].unreliable = true;
 	return err;
-}
-
-int btf_check_kfunc_arg_match(struct bpf_verifier_env *env,
-			      const struct btf *btf, u32 func_id,
-			      struct bpf_reg_state *regs,
-			      struct bpf_kfunc_arg_meta *meta)
-{
-	return btf_check_func_arg_match(env, btf, func_id, regs, true, meta, true);
 }
 
 /* Convert BTF of a function into bpf_reg_state if possible
···
 bool btf_is_module(const struct btf *btf)
 {
 	return btf->kernel_btf && strcmp(btf->name, "vmlinux") != 0;
-}
-
-static int btf_id_cmp_func(const void *a, const void *b)
-{
-	const int *pa = a, *pb = b;
-
-	return *pa - *pb;
-}
-
-bool btf_id_set_contains(const struct btf_id_set *set, u32 id)
-{
-	return bsearch(&id, set->ids, set->cnt, sizeof(u32), btf_id_cmp_func) != NULL;
-}
-
-static void *btf_id_set8_contains(const struct btf_id_set8 *set, u32 id)
-{
-	return bsearch(&id, set->pairs, set->cnt, sizeof(set->pairs[0]), btf_id_cmp_func);
 }
 
 enum {

kernel/bpf/core.c

···
 #include <linux/log2.h>
 #include <linux/bpf_verifier.h>
 #include <linux/nodemask.h>
+#include <linux/bpf_mem_alloc.h>
 
 #include <asm/barrier.h>
 #include <asm/unaligned.h>
···
 #define ARG1	regs[BPF_REG_ARG1]
 #define CTX	regs[BPF_REG_CTX]
 #define IMM	insn->imm
+
+struct bpf_mem_alloc bpf_global_ma;
+bool bpf_global_ma_set;
 
 /* No hurry in this branch
  *
···
 {
 	return -ENOTSUPP;
 }
+
+#ifdef CONFIG_BPF_SYSCALL
+static int __init bpf_global_ma_init(void)
+{
+	int ret;
+
+	ret = bpf_mem_alloc_init(&bpf_global_ma, 0, false);
+	bpf_global_ma_set = !ret;
+	return ret;
+}
+late_initcall(bpf_global_ma_init);
+#endif
 
 DEFINE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
 EXPORT_SYMBOL(bpf_stats_enabled_key);

kernel/bpf/hashtab.c

···
 		prealloc_destroy(htab);
 	}
 
-	bpf_map_free_record(map);
 	free_percpu(htab->extra_elems);
 	bpf_map_area_free(htab->buckets);
 	bpf_mem_alloc_destroy(&htab->pcpu_ma);

kernel/bpf/helpers.c

···
 #include <linux/proc_ns.h>
 #include <linux/security.h>
 #include <linux/btf_ids.h>
+#include <linux/bpf_mem_alloc.h>
 
 #include "../../lib/kstrtox.h"
 
···
 	.gpl_only	= false,
 	.ret_type	= RET_VOID,
 	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
+	.arg1_btf_id    = BPF_PTR_POISON,
 };
 
 static inline void __bpf_spin_unlock_irqrestore(struct bpf_spin_lock *lock)
···
 	.gpl_only	= false,
 	.ret_type	= RET_VOID,
 	.arg1_type	= ARG_PTR_TO_SPIN_LOCK,
+	.arg1_btf_id    = BPF_PTR_POISON,
 };
 
 void copy_map_value_locked(struct bpf_map *map, void *dst, void *src,
···
 
 		obj -= field->list_head.node_offset;
 		head = head->next;
-		/* TODO: Rework later */
-		kfree(obj);
+		/* The contained type can also have resources, including a
+		 * bpf_list_head which needs to be freed.
+		 */
+		bpf_obj_free_fields(field->list_head.value_rec, obj);
+		/* bpf_mem_free requires migrate_disable(), since we can be
+		 * called from map free path as well apart from BPF program (as
+		 * part of map ops doing bpf_obj_free_fields).
+		 */
+		migrate_disable();
+		bpf_mem_free(&bpf_global_ma, obj);
+		migrate_enable();
 	}
 }
 
-BTF_SET8_START(tracing_btf_ids)
+__diag_push();
+__diag_ignore_all("-Wmissing-prototypes",
+		  "Global functions as their definitions will be in vmlinux BTF");
+
+void *bpf_obj_new_impl(u64 local_type_id__k, void *meta__ign)
+{
+	struct btf_struct_meta *meta = meta__ign;
+	u64 size = local_type_id__k;
+	void *p;
+
+	if (unlikely(!bpf_global_ma_set))
+		return NULL;
+	p = bpf_mem_alloc(&bpf_global_ma, size);
+	if (!p)
+		return NULL;
+	if (meta)
+		bpf_obj_init(meta->field_offs, p);
+	return p;
+}
+
+void bpf_obj_drop_impl(void *p__alloc, void *meta__ign)
+{
+	struct btf_struct_meta *meta = meta__ign;
+	void *p = p__alloc;
+
+	if (meta)
+		bpf_obj_free_fields(meta->record, p);
+	bpf_mem_free(&bpf_global_ma, p);
+}
+
+static void __bpf_list_add(struct bpf_list_node *node, struct bpf_list_head *head, bool tail)
+{
+	struct list_head *n = (void *)node, *h = (void *)head;
+
+	if (unlikely(!h->next))
+		INIT_LIST_HEAD(h);
+	if (unlikely(!n->next))
+		INIT_LIST_HEAD(n);
+	tail ? list_add_tail(n, h) : list_add(n, h);
+}
+
+void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node)
+{
+	return __bpf_list_add(node, head, false);
+}
+
+void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node)
+{
+	return __bpf_list_add(node, head, true);
+}
+
+static struct bpf_list_node *__bpf_list_del(struct bpf_list_head *head, bool tail)
+{
+	struct list_head *n, *h = (void *)head;
+
+	if (unlikely(!h->next))
+		INIT_LIST_HEAD(h);
+	if (list_empty(h))
+		return NULL;
+	n = tail ? h->prev : h->next;
+	list_del_init(n);
+	return (struct bpf_list_node *)n;
+}
+
+struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head)
+{
+	return __bpf_list_del(head, false);
+}
+
+struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head)
+{
+	return __bpf_list_del(head, true);
+}
+
+__diag_pop();
+
+BTF_SET8_START(generic_btf_ids)
 #ifdef CONFIG_KEXEC_CORE
 BTF_ID_FLAGS(func, crash_kexec, KF_DESTRUCTIVE)
 #endif
-BTF_SET8_END(tracing_btf_ids)
+BTF_ID_FLAGS(func, bpf_obj_new_impl, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_obj_drop_impl, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_list_push_front)
+BTF_ID_FLAGS(func, bpf_list_push_back)
+BTF_ID_FLAGS(func, bpf_list_pop_front, KF_ACQUIRE | KF_RET_NULL)
+BTF_ID_FLAGS(func, bpf_list_pop_back, KF_ACQUIRE | KF_RET_NULL)
+BTF_SET8_END(generic_btf_ids)
 
-static const struct btf_kfunc_id_set tracing_kfunc_set = {
+static const struct btf_kfunc_id_set generic_kfunc_set = {
 	.owner = THIS_MODULE,
-	.set   = &tracing_btf_ids,
+	.set   = &generic_btf_ids,
 };
 
 static int __init kfunc_init(void)
 {
-	return register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &tracing_kfunc_set);
+	int ret;
+
+	ret = register_btf_kfunc_id_set(BPF_PROG_TYPE_TRACING, &generic_kfunc_set);
+	if (ret)
+		return ret;
+	return register_btf_kfunc_id_set(BPF_PROG_TYPE_SCHED_CLS, &generic_kfunc_set);
 }
 
 late_initcall(kfunc_init);

kernel/bpf/map_in_map.c

···
 	struct bpf_map *inner_map, *inner_map_meta;
 	u32 inner_map_meta_size;
 	struct fd f;
+	int ret;
 
 	f = fdget(inner_map_ufd);
 	inner_map = __bpf_map_get(f);
···
 
 	/* Does not support >1 level map-in-map */
 	if (inner_map->inner_map_meta) {
-		fdput(f);
-		return ERR_PTR(-EINVAL);
+		ret = -EINVAL;
+		goto put;
 	}
 
 	if (!inner_map->ops->map_meta_equal) {
-		fdput(f);
-		return ERR_PTR(-ENOTSUPP);
-	}
-
-	if (btf_record_has_field(inner_map->record, BPF_SPIN_LOCK)) {
-		fdput(f);
-		return ERR_PTR(-ENOTSUPP);
+		ret = -ENOTSUPP;
+		goto put;
 	}
 
 	inner_map_meta_size = sizeof(*inner_map_meta);
···
 
 	inner_map_meta = kzalloc(inner_map_meta_size, GFP_USER);
 	if (!inner_map_meta) {
-		fdput(f);
-		return ERR_PTR(-ENOMEM);
+		ret = -ENOMEM;
+		goto put;
 	}
 
 	inner_map_meta->map_type = inner_map->map_type;
···
 	inner_map_meta->value_size = inner_map->value_size;
 	inner_map_meta->map_flags = inner_map->map_flags;
 	inner_map_meta->max_entries = inner_map->max_entries;
+
 	inner_map_meta->record = btf_record_dup(inner_map->record);
 	if (IS_ERR(inner_map_meta->record)) {
 		/* btf_record_dup returns NULL or valid pointer in case of
 		 * invalid/empty/valid, but ERR_PTR in case of errors. During
 		 * equality NULL or IS_ERR is equivalent.
 		 */
-		fdput(f);
-		return ERR_CAST(inner_map_meta->record);
+		ret = PTR_ERR(inner_map_meta->record);
+		goto free;
 	}
+	if (inner_map_meta->record) {
+		struct btf_field_offs *field_offs;
+		/* If btf_record is !IS_ERR_OR_NULL, then field_offs is always
+		 * valid.
+		 */
+		field_offs = kmemdup(inner_map->field_offs, sizeof(*inner_map->field_offs), GFP_KERNEL | __GFP_NOWARN);
+		if (!field_offs) {
+			ret = -ENOMEM;
+			goto free_rec;
+		}
+		inner_map_meta->field_offs = field_offs;
+	}
+	/* Note: We must use the same BTF, as we also used btf_record_dup above
+	 * which relies on BTF being same for both maps, as some members like
+	 * record->fields.list_head have pointers like value_rec pointing into
+	 * inner_map->btf.
+	 */
 	if (inner_map->btf) {
 		btf_get(inner_map->btf);
 		inner_map_meta->btf = inner_map->btf;
···
 
 	fdput(f);
 	return inner_map_meta;
+free_rec:
+	btf_record_free(inner_map_meta->record);
+free:
+	kfree(inner_map_meta);
+put:
+	fdput(f);
+	return ERR_PTR(ret);
 }
 
 void bpf_map_meta_free(struct bpf_map *map_meta)
 {
+	kfree(map_meta->field_offs);
 	bpf_map_free_record(map_meta);
 	btf_put(map_meta->btf);
 	kfree(map_meta);

kernel/bpf/syscall.c

···
 			btf_put(rec->fields[i].kptr.btf);
 			break;
 		case BPF_LIST_HEAD:
+		case BPF_LIST_NODE:
 			/* Nothing to release for bpf_list_head */
 			break;
 		default:
···
 			}
 			break;
 		case BPF_LIST_HEAD:
+		case BPF_LIST_NODE:
 			/* Nothing to acquire for bpf_list_head */
 			break;
 		default:
···
 	if (rec_a->cnt != rec_b->cnt)
 		return false;
 	size = offsetof(struct btf_record, fields[rec_a->cnt]);
+	/* btf_parse_fields uses kzalloc to allocate a btf_record, so unused
+	 * members are zeroed out. So memcmp is safe to do without worrying
+	 * about padding/unused fields.
+	 *
+	 * While spin_lock, timer, and kptr have no relation to map BTF,
+	 * list_head metadata is specific to map BTF, the btf and value_rec
+	 * members in particular. btf is the map BTF, while value_rec points to
+	 * btf_record in that map BTF.
+	 *
+	 * So while by default, we don't rely on the map BTF (which the records
+	 * were parsed from) matching for both records, which is not backwards
+	 * compatible, in case list_head is part of it, we implicitly rely on
+	 * that by way of depending on memcmp succeeding for it.
+	 */
 	return !memcmp(rec_a, rec_b, size);
 }
 
···
 				continue;
 			bpf_list_head_free(field, field_ptr, obj + rec->spin_lock_off);
 			break;
+		case BPF_LIST_NODE:
+			break;
 		default:
 			WARN_ON_ONCE(1);
 			continue;
···
 static void bpf_map_free_deferred(struct work_struct *work)
 {
 	struct bpf_map *map = container_of(work, struct bpf_map, work);
+	struct btf_field_offs *foffs = map->field_offs;
+	struct btf_record *rec = map->record;
 
 	security_bpf_map_free(map);
-	kfree(map->field_offs);
 	bpf_map_release_memcg(map);
-	/* implementation dependent freeing, map_free callback also does
-	 * bpf_map_free_record, if needed.
-	 */
+	/* implementation dependent freeing */
 	map->ops->map_free(map);
+	/* Delay freeing of field_offs and btf_record for maps, as map_free
+	 * callback usually needs access to them. It is better to do it here
+	 * than require each callback to do the free itself manually.
+	 *
+	 * Note that the btf_record stashed in map->inner_map_meta->record was
+	 * already freed using the map_free callback for map in map case which
+	 * eventually calls bpf_map_free_meta, since inner_map_meta is only a
+	 * template bpf_map struct used during verification.
+	 */
+	kfree(foffs);
+	btf_record_free(rec);
 }
 
 static void bpf_map_put_uref(struct bpf_map *map)
···
 				if (map->map_type != BPF_MAP_TYPE_HASH &&
 				    map->map_type != BPF_MAP_TYPE_LRU_HASH &&
 				    map->map_type != BPF_MAP_TYPE_ARRAY) {
-					return -EOPNOTSUPP;
+					ret = -EOPNOTSUPP;
 					goto free_map_tab;
 				}
 				break;
···
 			}
 		}
 	}
+
+	ret = btf_check_and_fixup_fields(btf, map->record);
+	if (ret < 0)
+		goto free_map_tab;
 
 	if (map->ops->map_check_btf) {
 		ret = map->ops->map_check_btf(map, btf, key_type, value_type);

kernel/bpf/verifier.c

···
 		type == PTR_TO_SOCK_COMMON;
 }
 
+static struct btf_record *reg_btf_record(const struct bpf_reg_state *reg)
+{
+	struct btf_record *rec = NULL;
+	struct btf_struct_meta *meta;
+
+	if (reg->type == PTR_TO_MAP_VALUE) {
+		rec = reg->map_ptr->record;
+	} else if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC)) {
+		meta = btf_find_struct_meta(reg->btf, reg->btf_id);
+		if (meta)
+			rec = meta->record;
+	}
+	return rec;
+}
+
 static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
 {
-	return reg->type == PTR_TO_MAP_VALUE &&
-	       btf_record_has_field(reg->map_ptr->record, BPF_SPIN_LOCK);
+	return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK);
 }
 
 static bool type_is_rdonly_mem(u32 type)
···
 	}
 	dst_state->speculative = src->speculative;
 	dst_state->curframe = src->curframe;
-	dst_state->active_spin_lock = src->active_spin_lock;
+	dst_state->active_lock.ptr = src->active_lock.ptr;
+	dst_state->active_lock.id = src->active_lock.id;
 	dst_state->branches = src->branches;
 	dst_state->parent = src->parent;
 	dst_state->first_insn_idx = src->first_insn_idx;
···
 		return -EACCES;
 	}
 
-	if (env->ops->btf_struct_access) {
+	if (env->ops->btf_struct_access && !type_is_alloc(reg->type)) {
+		if (!btf_is_kernel(reg->btf)) {
+			verbose(env, "verifier internal error: reg->btf must be kernel btf\n");
+			return -EFAULT;
+		}
 		ret = env->ops->btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag);
 	} else {
-		if (atype != BPF_READ) {
+		/* Writes are permitted with default btf_struct_access for
+		 * program allocated objects (which always have ref_obj_id > 0),
+		 * but not for untrusted PTR_TO_BTF_ID | MEM_ALLOC.
+		 */
+		if (atype != BPF_READ && reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
 			verbose(env, "only read is supported\n");
 			return -EACCES;
+		}
+
+		if (type_is_alloc(reg->type) && !reg->ref_obj_id) {
+			verbose(env, "verifier internal error: ref_obj_id for allocated object must be non-zero\n");
+			return -EFAULT;
 		}
 
 		ret = btf_struct_access(&env->log, reg, off, size, atype, &btf_id, &flag);
···
 	return err;
 }
 
-int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
-			     u32 regno)
+static int check_kfunc_mem_size_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+				    u32 regno)
 {
 	struct bpf_reg_state *mem_reg = &cur_regs(env)[regno - 1];
 	bool may_be_null = type_may_be_null(mem_reg->type);
···
 }
 
 /* Implementation details:
- * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL
+ * bpf_map_lookup returns PTR_TO_MAP_VALUE_OR_NULL.
+ * bpf_obj_new returns PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL.
  * Two bpf_map_lookups (even with the same key) will have different reg->id.
- * For traditional PTR_TO_MAP_VALUE the verifier clears reg->id after
- * value_or_null->value transition, since the verifier only cares about
- * the range of access to valid map value pointer and doesn't care about actual
- * address of the map element.
+ * Two separate bpf_obj_new will also have different reg->id.
+ * For traditional PTR_TO_MAP_VALUE or PTR_TO_BTF_ID | MEM_ALLOC, the verifier
+ * clears reg->id after value_or_null->value transition, since the verifier only
+ * cares about the range of access to valid map value pointer and doesn't care
+ * about actual address of the map element.
  * For maps with 'struct bpf_spin_lock' inside map value the verifier keeps
  * reg->id > 0 after value_or_null->value transition. By doing so
  * two bpf_map_lookups will be considered two different pointers that
- * point to different bpf_spin_locks.
+ * point to different bpf_spin_locks. Likewise for pointers to allocated objects
+ * returned from bpf_obj_new.
  * The verifier allows taking only one bpf_spin_lock at a time to avoid
  * dead-locks.
  * Since only one bpf_spin_lock is allowed the checks are simpler than
  * reg_is_refcounted() logic. The verifier needs to remember only
  * one spin_lock instead of array of acquired_refs.
- * cur_state->active_spin_lock remembers which map value element got locked
- * and clears it after bpf_spin_unlock.
+ * cur_state->active_lock remembers which map value element or allocated
+ * object got locked and clears it after bpf_spin_unlock.
  */
 static int process_spin_lock(struct bpf_verifier_env *env, int regno,
 			     bool is_lock)
···
 	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
 	struct bpf_verifier_state *cur = env->cur_state;
 	bool is_const = tnum_is_const(reg->var_off);
-	struct bpf_map *map = reg->map_ptr;
 	u64 val = reg->var_off.value;
+	struct bpf_map *map = NULL;
+	struct btf *btf = NULL;
+	struct btf_record *rec;
 
 	if (!is_const) {
 		verbose(env,
···
 			regno);
 		return -EINVAL;
 	}
-	if (!map->btf) {
-		verbose(env,
-			"map '%s' has to have BTF in order to use bpf_spin_lock\n",
-			map->name);
+	if (reg->type == PTR_TO_MAP_VALUE) {
+		map = reg->map_ptr;
+		if (!map->btf) {
+			verbose(env,
+				"map '%s' has to have BTF in order to use bpf_spin_lock\n",
+				map->name);
+			return -EINVAL;
+		}
+	} else {
+		btf = reg->btf;
+	}
+
+	rec = reg_btf_record(reg);
+	if (!btf_record_has_field(rec, BPF_SPIN_LOCK)) {
+		verbose(env, "%s '%s' has no valid bpf_spin_lock\n", map ? "map" : "local",
+			map ? map->name : "kptr");
 		return -EINVAL;
 	}
-	if (!btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
-		verbose(env, "map '%s' has no valid bpf_spin_lock\n", map->name);
-		return -EINVAL;
-	}
-	if (map->record->spin_lock_off != val + reg->off) {
+	if (rec->spin_lock_off != val + reg->off) {
 		verbose(env, "off %lld doesn't point to 'struct bpf_spin_lock' that is at %d\n",
-			val + reg->off, map->record->spin_lock_off);
+			val + reg->off, rec->spin_lock_off);
 		return -EINVAL;
 	}
 	if (is_lock) {
-		if (cur->active_spin_lock) {
+		if (cur->active_lock.ptr) {
 			verbose(env,
 				"Locking two bpf_spin_locks are not allowed\n");
 			return -EINVAL;
 		}
-		cur->active_spin_lock = reg->id;
+		if (map)
+			cur->active_lock.ptr = map;
+		else
+			cur->active_lock.ptr = btf;
+		cur->active_lock.id = reg->id;
 	} else {
-		if (!cur->active_spin_lock) {
+		struct bpf_func_state *fstate = cur_func(env);
+		void *ptr;
+		int i;
+
+		if (map)
+			ptr = map;
+		else
+			ptr = btf;
+
+		if (!cur->active_lock.ptr) {
 			verbose(env, "bpf_spin_unlock without taking a lock\n");
 			return -EINVAL;
 		}
-		if (cur->active_spin_lock != reg->id) {
+		if (cur->active_lock.ptr != ptr ||
+		    cur->active_lock.id != reg->id) {
 			verbose(env, "bpf_spin_unlock of different lock\n");
 			return -EINVAL;
 		}
-		cur->active_spin_lock = 0;
+		cur->active_lock.ptr = NULL;
+		cur->active_lock.id = 0;
+
+		for (i = 0; i < fstate->acquired_refs; i++) {
+			int err;
+
+			/* Complain on error because this reference state cannot
+			 * be freed before this point, as bpf_spin_lock critical
+			 * section does not allow functions that release the
+			 * allocated object immediately.
+			 */
+			if (!fstate->refs[i].release_on_unlock)
+				continue;
+			err = release_reference(env, fstate->refs[i].id);
+			if (err) {
+				verbose(env, "failed to release release_on_unlock reference");
+				return err;
+			}
+		}
 	}
 	return 0;
 }
···
 	},
 };
 
+static const struct bpf_reg_types spin_lock_types = {
+	.types = {
+		PTR_TO_MAP_VALUE,
+		PTR_TO_BTF_ID | MEM_ALLOC,
+	}
+};
+
 static const struct bpf_reg_types fullsock_types = { .types = { PTR_TO_SOCKET } };
 static const struct bpf_reg_types scalar_types = { .types = { SCALAR_VALUE } };
 static const struct bpf_reg_types context_types = { .types = { PTR_TO_CTX } };
 static const struct bpf_reg_types ringbuf_mem_types = { .types = { PTR_TO_MEM | MEM_RINGBUF } };
 static const struct bpf_reg_types const_map_ptr_types = { .types = { CONST_PTR_TO_MAP } };
 static const struct bpf_reg_types btf_ptr_types = { .types = { PTR_TO_BTF_ID } };
-static const struct bpf_reg_types spin_lock_types = { .types = { PTR_TO_MAP_VALUE } };
 static const struct bpf_reg_types percpu_btf_ptr_types = { .types = { PTR_TO_BTF_ID | MEM_PERCPU } };
 static const struct bpf_reg_types func_ptr_types = { .types = { PTR_TO_FUNC } };
 static const struct bpf_reg_types stack_ptr_types = { .types = { PTR_TO_STACK } };
···
 				return -EACCES;
 			}
 		}
+	} else if (type_is_alloc(reg->type)) {
+		if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock) {
+			verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n");
+			return -EFAULT;
+		}
 	}
 
 	return 0;
···
 	 * fixed offset.
 	 */
 	case PTR_TO_BTF_ID:
+	case PTR_TO_BTF_ID | MEM_ALLOC:
 		/* When referenced PTR_TO_BTF_ID is passed to release function,
 		 * it's fixed offset must be 0.	In the other cases, fixed offset
 		 * can be non-zero.
···
 		goto skip_type_check;
 
 	/* arg_btf_id and arg_size are in a union. */
-	if (base_type(arg_type) == ARG_PTR_TO_BTF_ID)
+	if (base_type(arg_type) == ARG_PTR_TO_BTF_ID ||
+	    base_type(arg_type) == ARG_PTR_TO_SPIN_LOCK)
 		arg_btf_id = fn->arg_btf_id[arg];
 
 	err = check_reg_type(env, regno, arg_type, arg_btf_id, meta);
···
 	int i;
 
 	for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
-		if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID && !fn->arg_btf_id[i])
-			return false;
-
+		if (base_type(fn->arg_type[i]) == ARG_PTR_TO_BTF_ID)
+			return !!fn->arg_btf_id[i];
+		if (base_type(fn->arg_type[i]) == ARG_PTR_TO_SPIN_LOCK)
+			return fn->arg_btf_id[i] == BPF_PTR_POISON;
 		if (base_type(fn->arg_type[i]) != ARG_PTR_TO_BTF_ID && fn->arg_btf_id[i] &&
 		    /* arg_btf_id and arg_size are in a union. */
 		    (base_type(fn->arg_type[i]) != ARG_PTR_TO_MEM ||
···
 	}
 }
 
+struct bpf_kfunc_call_arg_meta {
+	/* In parameters */
+	struct btf *btf;
+	u32 func_id;
+	u32 kfunc_flags;
+	const struct btf_type *func_proto;
+	const char *func_name;
+	/* Out parameters */
+	u32 ref_obj_id;
+	u8 release_regno;
+	bool r0_rdonly;
+	u64 r0_size;
+	struct {
+		u64 value;
+		bool found;
+	} arg_constant;
+	struct {
+		struct btf *btf;
+		u32 btf_id;
+	} arg_obj_drop;
+	struct {
+		struct btf_field *field;
+	} arg_list_head;
+};
+
+static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_ACQUIRE;
+}
+
+static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_RET_NULL;
+}
+
+static bool is_kfunc_release(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_RELEASE;
+}
+
+static bool is_kfunc_trusted_args(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_TRUSTED_ARGS;
+}
+
+static bool is_kfunc_sleepable(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_SLEEPABLE;
+}
+
+static bool is_kfunc_destructive(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_DESTRUCTIVE;
+}
+
+static bool is_kfunc_arg_kptr_get(struct bpf_kfunc_call_arg_meta *meta, int arg)
+{
+	return arg == 0 && (meta->kfunc_flags & KF_KPTR_GET);
+}
+
+static bool __kfunc_param_match_suffix(const struct btf *btf,
+				       const struct btf_param *arg,
+				       const char *suffix)
+{
+	int suffix_len = strlen(suffix), len;
+	const char *param_name;
+
+	/* In the future, this can be ported to use BTF tagging */
+	param_name = btf_name_by_offset(btf, arg->name_off);
+	if (str_is_empty(param_name))
+		return false;
+	len = strlen(param_name);
+	if (len < suffix_len)
+		return false;
+	param_name += len - suffix_len;
+	return !strncmp(param_name, suffix, suffix_len);
+}
+
+static bool is_kfunc_arg_mem_size(const struct btf *btf,
+				  const struct btf_param *arg,
+				  const struct bpf_reg_state *reg)
+{
+	const struct btf_type *t;
+
+	t = btf_type_skip_modifiers(btf, arg->type, NULL);
+	if (!btf_type_is_scalar(t) || reg->type != SCALAR_VALUE)
+		return false;
+
+	return __kfunc_param_match_suffix(btf, arg, "__sz");
+}
+
+static bool is_kfunc_arg_constant(const struct btf *btf, const struct btf_param *arg)
+{
+	return __kfunc_param_match_suffix(btf, arg, "__k");
+}
+
+static bool is_kfunc_arg_ignore(const struct btf *btf, const struct btf_param *arg)
+{
+	return __kfunc_param_match_suffix(btf, arg, "__ign");
+}
+
+static bool is_kfunc_arg_alloc_obj(const struct btf *btf, const struct btf_param *arg)
+{
+	return __kfunc_param_match_suffix(btf, arg, "__alloc");
+}
+
+static bool is_kfunc_arg_scalar_with_name(const struct btf *btf,
+					  const struct btf_param *arg,
+					  const char *name)
+{
+	int len, target_len = strlen(name);
+	const char *param_name;
+
+	param_name = btf_name_by_offset(btf, arg->name_off);
+	if (str_is_empty(param_name))
+		return false;
+	len = strlen(param_name);
+	if (len != target_len)
+		return false;
+	if (strcmp(param_name, name))
+		return false;
+
+	return true;
+}
+
+enum {
+	KF_ARG_DYNPTR_ID,
+	KF_ARG_LIST_HEAD_ID,
+	KF_ARG_LIST_NODE_ID,
+};
+
+BTF_ID_LIST(kf_arg_btf_ids)
+BTF_ID(struct, bpf_dynptr_kern)
+BTF_ID(struct, bpf_list_head)
+BTF_ID(struct, bpf_list_node)
+
+static bool __is_kfunc_ptr_arg_type(const struct btf *btf,
+				    const struct btf_param *arg, int type)
+{
+	const struct btf_type *t;
+	u32 res_id;
+
+	t = btf_type_skip_modifiers(btf, arg->type, NULL);
+	if (!t)
+		return false;
+	if (!btf_type_is_ptr(t))
+		return false;
+	t = btf_type_skip_modifiers(btf, t->type, &res_id);
+	if (!t)
+		return false;
+	return btf_types_are_same(btf, res_id, btf_vmlinux, kf_arg_btf_ids[type]);
+}
+
+static bool is_kfunc_arg_dynptr(const struct btf *btf, const struct btf_param *arg)
+{
+	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_DYNPTR_ID);
+}
+
+static bool is_kfunc_arg_list_head(const struct btf *btf, const struct btf_param *arg)
+{
+	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_HEAD_ID);
+}
+
+static bool is_kfunc_arg_list_node(const struct btf *btf, const struct btf_param *arg)
+{
+	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_LIST_NODE_ID);
+}
+
+/* Returns true if struct is composed of scalars, 4 levels of nesting allowed */
+static bool __btf_type_is_scalar_struct(struct bpf_verifier_env *env,
+					const struct btf *btf,
+					const struct btf_type *t, int rec)
+{
+	const struct btf_type *member_type;
+	const struct btf_member *member;
+	u32 i;
+
+	if (!btf_type_is_struct(t))
+		return false;
+
+	for_each_member(i, t, member) {
+		const struct btf_array *array;
+
+		member_type = btf_type_skip_modifiers(btf, member->type, NULL);
+		if (btf_type_is_struct(member_type)) {
+			if (rec >= 3) {
+				verbose(env, "max struct nesting depth exceeded\n");
+				return false;
+			}
+			if (!__btf_type_is_scalar_struct(env, btf, member_type, rec + 1))
+				return false;
+			continue;
+		}
+		if (btf_type_is_array(member_type)) {
+			array = btf_array(member_type);
+			if (!array->nelems)
+				return false;
+			member_type = btf_type_skip_modifiers(btf, array->type, NULL);
+			if (!btf_type_is_scalar(member_type))
+				return false;
+			continue;
+		}
+		if (!btf_type_is_scalar(member_type))
+			return false;
+	}
+	return true;
+}
+
+
+static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = {
+#ifdef CONFIG_NET
+	[PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK],
+	[PTR_TO_SOCK_COMMON] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+	[PTR_TO_TCP_SOCK] = &btf_sock_ids[BTF_SOCK_TYPE_TCP],
+#endif
+};
+
+enum kfunc_ptr_arg_type {
+	KF_ARG_PTR_TO_CTX,
+	KF_ARG_PTR_TO_ALLOC_BTF_ID,  /* Allocated object */
+	KF_ARG_PTR_TO_KPTR,	     /* PTR_TO_KPTR but type specific */
+	KF_ARG_PTR_TO_DYNPTR,
+	KF_ARG_PTR_TO_LIST_HEAD,
+	KF_ARG_PTR_TO_LIST_NODE,
+	KF_ARG_PTR_TO_BTF_ID,	     /* Also covers reg2btf_ids conversions */
+	KF_ARG_PTR_TO_MEM,
+	KF_ARG_PTR_TO_MEM_SIZE,	     /* Size derived from next argument, skip it */
+};
+
+enum special_kfunc_type {
+	KF_bpf_obj_new_impl,
+	KF_bpf_obj_drop_impl,
+	KF_bpf_list_push_front,
+	KF_bpf_list_push_back,
+	KF_bpf_list_pop_front,
+	KF_bpf_list_pop_back,
+};
+
+BTF_SET_START(special_kfunc_set)
+BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_list_push_front)
+BTF_ID(func, bpf_list_push_back)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+BTF_SET_END(special_kfunc_set)
+
+BTF_ID_LIST(special_kfunc_list)
+BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_list_push_front)
+BTF_ID(func, bpf_list_push_back)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+
+static enum kfunc_ptr_arg_type
+get_kfunc_ptr_arg_type(struct bpf_verifier_env *env,
+		       struct bpf_kfunc_call_arg_meta *meta,
+		       const struct btf_type *t, const struct btf_type *ref_t,
+		       const char *ref_tname, const struct btf_param *args,
+		       int argno, int nargs)
+{
+	u32 regno = argno + 1;
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = &regs[regno];
+	bool arg_mem_size = false;
+
+	/* In this function, we verify the kfunc's BTF as per the argument type,
+	 * leaving the rest of the verification with respect to the register
+	 * type to our caller. When a set of conditions hold in the BTF type of
+	 * arguments, we resolve it to a known kfunc_ptr_arg_type.
+	 */
+	if (btf_get_prog_ctx_type(&env->log, meta->btf, t, resolve_prog_type(env->prog), argno))
+		return KF_ARG_PTR_TO_CTX;
+
+	if (is_kfunc_arg_alloc_obj(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_ALLOC_BTF_ID;
+
+	if (is_kfunc_arg_kptr_get(meta, argno)) {
+		if (!btf_type_is_ptr(ref_t)) {
+			verbose(env, "arg#0 BTF type must be a double pointer for kptr_get kfunc\n");
+			return -EINVAL;
+		}
+		ref_t = btf_type_by_id(meta->btf, ref_t->type);
+		ref_tname = btf_name_by_offset(meta->btf, ref_t->name_off);
+		if (!btf_type_is_struct(ref_t)) {
+			verbose(env, "kernel function %s args#0 pointer type %s %s is not supported\n",
+				meta->func_name, btf_type_str(ref_t), ref_tname);
+			return -EINVAL;
+		}
+		return KF_ARG_PTR_TO_KPTR;
+	}
+
+	if (is_kfunc_arg_dynptr(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_DYNPTR;
+
+	if (is_kfunc_arg_list_head(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_LIST_HEAD;
+
+	if (is_kfunc_arg_list_node(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_LIST_NODE;
+
+	if ((base_type(reg->type) == PTR_TO_BTF_ID || reg2btf_ids[base_type(reg->type)])) {
+		if (!btf_type_is_struct(ref_t)) {
+			verbose(env, "kernel function %s args#%d pointer type %s %s is not supported\n",
+				meta->func_name, argno, btf_type_str(ref_t), ref_tname);
+			return -EINVAL;
+		}
+		return KF_ARG_PTR_TO_BTF_ID;
+	}
+
+	if (argno + 1 < nargs && is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1]))
+		arg_mem_size = true;
+
+	/* This is the catch all argument type of register types supported by
+	 * check_helper_mem_access. However, we only allow when argument type is
+	 * pointer to scalar, or struct composed (recursively) of scalars. When
+	 * arg_mem_size is true, the pointer can be void *.
+	 */
+	if (!btf_type_is_scalar(ref_t) && !__btf_type_is_scalar_struct(env, meta->btf, ref_t, 0) &&
+	    (arg_mem_size ? !btf_type_is_void(ref_t) : 1)) {
+		verbose(env, "arg#%d pointer type %s %s must point to %sscalar, or struct with scalar\n",
+			argno, btf_type_str(ref_t), ref_tname, arg_mem_size ? "void, " : "");
+		return -EINVAL;
+	}
+	return arg_mem_size ? KF_ARG_PTR_TO_MEM_SIZE : KF_ARG_PTR_TO_MEM;
+}
+
+static int process_kf_arg_ptr_to_btf_id(struct bpf_verifier_env *env,
+					struct bpf_reg_state *reg,
+					const struct btf_type *ref_t,
+					const char *ref_tname, u32 ref_id,
+					struct bpf_kfunc_call_arg_meta *meta,
+					int argno)
+{
+	const struct btf_type *reg_ref_t;
+	bool strict_type_match = false;
+	const struct btf *reg_btf;
+	const char *reg_ref_tname;
+	u32 reg_ref_id;
+
+	if (reg->type == PTR_TO_BTF_ID) {
+		reg_btf = reg->btf;
+		reg_ref_id = reg->btf_id;
+	} else {
+		reg_btf = btf_vmlinux;
+		reg_ref_id = *reg2btf_ids[base_type(reg->type)];
+	}
+
+	if (is_kfunc_trusted_args(meta) || (is_kfunc_release(meta) && reg->ref_obj_id))
+		strict_type_match = true;
+
+	reg_ref_t = btf_type_skip_modifiers(reg_btf, reg_ref_id, &reg_ref_id);
+	reg_ref_tname = btf_name_by_offset(reg_btf, reg_ref_t->name_off);
+	if (!btf_struct_ids_match(&env->log, reg_btf, reg_ref_id, reg->off, meta->btf, ref_id, strict_type_match)) {
+		verbose(env, "kernel function %s args#%d expected pointer to %s %s but R%d has a pointer to %s %s\n",
+			meta->func_name, argno, btf_type_str(ref_t), ref_tname, argno + 1,
+			btf_type_str(reg_ref_t), reg_ref_tname);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int process_kf_arg_ptr_to_kptr(struct bpf_verifier_env *env,
+				      struct bpf_reg_state *reg,
+				      const struct btf_type *ref_t,
+				      const char *ref_tname,
+				      struct bpf_kfunc_call_arg_meta *meta,
+				      int argno)
+{
+	struct btf_field *kptr_field;
+
+	/* check_func_arg_reg_off allows var_off for
+	 * PTR_TO_MAP_VALUE, but we need fixed offset to find
+	 * off_desc.
+	 */
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env, "arg#0 must have constant offset\n");
+		return -EINVAL;
+	}
+
+	kptr_field = btf_record_find(reg->map_ptr->record, reg->off + reg->var_off.value, BPF_KPTR);
+	if (!kptr_field || kptr_field->type != BPF_KPTR_REF) {
+		verbose(env, "arg#0 no referenced kptr at map value offset=%llu\n",
+			reg->off + reg->var_off.value);
+		return -EINVAL;
+	}
+
+	if (!btf_struct_ids_match(&env->log, meta->btf, ref_t->type, 0, kptr_field->kptr.btf,
+				  kptr_field->kptr.btf_id, true)) {
+		verbose(env, "kernel function %s args#%d expected pointer to %s %s\n",
+			meta->func_name, argno, btf_type_str(ref_t), ref_tname);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static int ref_set_release_on_unlock(struct bpf_verifier_env *env, u32 ref_obj_id)
+{
+	struct bpf_func_state *state = cur_func(env);
+	struct bpf_reg_state *reg;
+	int i;
+
+	/* bpf_spin_lock only allows calling list_push and list_pop, no BPF
+	 * subprogs, no global functions. This means that the references would
+	 * not be released inside the critical section but they may be added to
+	 * the reference state, and the acquired_refs are never copied out for a
+	 * different frame as BPF to BPF calls don't work in bpf_spin_lock
+	 * critical sections.
+	 */
+	if (!ref_obj_id) {
+		verbose(env, "verifier internal error: ref_obj_id is zero for release_on_unlock\n");
+		return -EFAULT;
+	}
+	for (i = 0; i < state->acquired_refs; i++) {
+		if (state->refs[i].id == ref_obj_id) {
+			if (state->refs[i].release_on_unlock) {
+				verbose(env, "verifier internal error: expected false release_on_unlock");
+				return -EFAULT;
+			}
+			state->refs[i].release_on_unlock = true;
+			/* Now mark everyone sharing same ref_obj_id as untrusted */
+			bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+				if (reg->ref_obj_id == ref_obj_id)
+					reg->type |= PTR_UNTRUSTED;
+			}));
+			return 0;
+		}
+	}
+	verbose(env, "verifier internal error: ref state missing for ref_obj_id\n");
+	return -EFAULT;
+}
+
+/* Implementation details:
+ *
+ * Each register points to some region of memory, which we define as an
+ * allocation. Each allocation may embed a bpf_spin_lock which protects any
+ * special BPF objects (bpf_list_head, bpf_rb_root, etc.) part of the same
+ * allocation. The lock and the data it protects are colocated in the same
+ * memory region.
+ *
+ * Hence, everytime a register holds a pointer value pointing to such
+ * allocation, the verifier preserves a unique reg->id for it.
+ *
+ * The verifier remembers the lock 'ptr' and the lock 'id' whenever
+ * bpf_spin_lock is called.
+ *
+ * To enable this, lock state in the verifier captures two values:
+ *	active_lock.ptr = Register's type specific pointer
+ *	active_lock.id  = A unique ID for each register pointer value
+ *
+ * Currently, PTR_TO_MAP_VALUE and PTR_TO_BTF_ID | MEM_ALLOC are the two
+ * supported register types.
+ *
+ * The active_lock.ptr in case of map values is the reg->map_ptr, and in case of
+ * allocated objects is the reg->btf pointer.
+ *
+ * The active_lock.id is non-unique for maps supporting direct_value_addr, as we
+ * can establish the provenance of the map value statically for each distinct
+ * lookup into such maps. They always contain a single map value hence unique
+ * IDs for each pseudo load pessimizes the algorithm and rejects valid programs.
+ *
+ * So, in case of global variables, they use array maps with max_entries = 1,
+ * hence their active_lock.ptr becomes map_ptr and id = 0 (since they all point
+ * into the same map value as max_entries is 1, as described above).
+ *
+ * In case of inner map lookups, the inner map pointer has same map_ptr as the
+ * outer map pointer (in verifier context), but each lookup into an inner map
+ * assigns a fresh reg->id to the lookup, so while lookups into distinct inner
+ * maps from the same outer map share the same map_ptr as active_lock.ptr, they
+ * will get different reg->id assigned to each lookup, hence different
+ * active_lock.id.
+ *
+ * In case of allocated objects, active_lock.ptr is the reg->btf, and the
+ * reg->id is a unique ID preserved after the NULL pointer check on the pointer
+ * returned from bpf_obj_new. Each allocation receives a new reg->id.
+ */
+static int check_reg_allocation_locked(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	void *ptr;
+	u32 id;
+
+	switch ((int)reg->type) {
+	case PTR_TO_MAP_VALUE:
+		ptr = reg->map_ptr;
+		break;
+	case PTR_TO_BTF_ID | MEM_ALLOC:
+		ptr = reg->btf;
+		break;
+	default:
+		verbose(env, "verifier internal error: unknown reg type for lock check\n");
+		return -EFAULT;
+	}
+	id = reg->id;
+
+	if (!env->cur_state->active_lock.ptr)
+		return -EINVAL;
+	if (env->cur_state->active_lock.ptr != ptr ||
+	    env->cur_state->active_lock.id != id) {
+		verbose(env, "held lock and object are not in the same allocation\n");
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static bool is_bpf_list_api_kfunc(u32 btf_id)
+{
+	return btf_id == special_kfunc_list[KF_bpf_list_push_front] ||
+	       btf_id == special_kfunc_list[KF_bpf_list_push_back] ||
+	       btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
+	       btf_id == special_kfunc_list[KF_bpf_list_pop_back];
+}
+
+static int process_kf_arg_ptr_to_list_head(struct bpf_verifier_env *env,
+					   struct bpf_reg_state *reg, u32 regno,
+					   struct bpf_kfunc_call_arg_meta *meta)
+{
+	struct btf_field *field;
+	struct btf_record *rec;
+	u32 list_head_off;
+
+	if (meta->btf != btf_vmlinux || !is_bpf_list_api_kfunc(meta->func_id)) {
+		verbose(env, "verifier internal error: bpf_list_head argument for unknown kfunc\n");
+		return -EFAULT;
+	}
+
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env,
+			"R%d doesn't have constant offset. bpf_list_head has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+
+	rec = reg_btf_record(reg);
+	list_head_off = reg->off + reg->var_off.value;
+	field = btf_record_find(rec, list_head_off, BPF_LIST_HEAD);
+	if (!field) {
+		verbose(env, "bpf_list_head not found at offset=%u\n", list_head_off);
+		return -EINVAL;
+	}
+
+	/* All functions require bpf_list_head to be protected using a bpf_spin_lock */
+	if (check_reg_allocation_locked(env, reg)) {
+		verbose(env, "bpf_spin_lock at off=%d must be held for bpf_list_head\n",
+			rec->spin_lock_off);
+		return -EINVAL;
+	}
+
+	if (meta->arg_list_head.field) {
+		verbose(env, "verifier internal error: repeating bpf_list_head arg\n");
+		return -EFAULT;
+	}
+	meta->arg_list_head.field = field;
+	return 0;
+}
+
+static int process_kf_arg_ptr_to_list_node(struct bpf_verifier_env *env,
+					   struct bpf_reg_state *reg, u32 regno,
+					   struct bpf_kfunc_call_arg_meta *meta)
+{
+	const struct btf_type *et, *t;
+	struct btf_field *field;
+	struct btf_record *rec;
+	u32 list_node_off;
+
+	if (meta->btf != btf_vmlinux ||
+	    (meta->func_id != special_kfunc_list[KF_bpf_list_push_front] &&
+	     meta->func_id != special_kfunc_list[KF_bpf_list_push_back])) {
+		verbose(env, "verifier internal error: bpf_list_node argument for unknown kfunc\n");
+		return -EFAULT;
+	}
+
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env,
+			"R%d doesn't have constant offset. bpf_list_node has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+
+	rec = reg_btf_record(reg);
+	list_node_off = reg->off + reg->var_off.value;
+	field = btf_record_find(rec, list_node_off, BPF_LIST_NODE);
+	if (!field || field->offset != list_node_off) {
+		verbose(env, "bpf_list_node not found at offset=%u\n", list_node_off);
+		return -EINVAL;
+	}
+
+	field = meta->arg_list_head.field;
+
+	et = btf_type_by_id(field->list_head.btf, field->list_head.value_btf_id);
+	t = btf_type_by_id(reg->btf, reg->btf_id);
+	if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, 0, field->list_head.btf,
+				  field->list_head.value_btf_id, true)) {
+		verbose(env, "operation on bpf_list_head expects arg#1 bpf_list_node at offset=%d "
+			"in struct %s, but arg is at offset=%d in struct %s\n",
+			field->list_head.node_offset, btf_name_by_offset(field->list_head.btf, et->name_off),
+			list_node_off, btf_name_by_offset(reg->btf, t->name_off));
+		return -EINVAL;
+	}
+
+	if (list_node_off != field->list_head.node_offset) {
+		verbose(env, "arg#1 offset=%d, but expected bpf_list_node at offset=%d in struct %s\n",
+			list_node_off, field->list_head.node_offset,
+			btf_name_by_offset(field->list_head.btf, et->name_off));
+		return -EINVAL;
+	}
+	/* Set arg#1 for expiration after unlock */
+	return ref_set_release_on_unlock(env, reg->ref_obj_id);
+}
+
+static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta)
+{
+	const char *func_name = meta->func_name, *ref_tname;
+	const struct btf *btf = meta->btf;
+	const struct btf_param *args;
+	u32 i, nargs;
+	int ret;
+
+	args = (const struct btf_param *)(meta->func_proto + 1);
+	nargs = btf_type_vlen(meta->func_proto);
+	if (nargs > MAX_BPF_FUNC_REG_ARGS) {
+		verbose(env, "Function %s has %d > %d args\n", func_name, nargs,
+			MAX_BPF_FUNC_REG_ARGS);
+		return -EINVAL;
+	}
+
+	/* Check that BTF function arguments match actual types that the
+	 * verifier sees.
+	 */
+	for (i = 0; i < nargs; i++) {
+		struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[i + 1];
+		const struct btf_type *t, *ref_t, *resolve_ret;
+		enum bpf_arg_type arg_type = ARG_DONTCARE;
+		u32 regno = i + 1, ref_id, type_size;
+		bool is_ret_buf_sz = false;
+		int kf_arg_type;
+
+		t = btf_type_skip_modifiers(btf, args[i].type, NULL);
+
+		if (is_kfunc_arg_ignore(btf, &args[i]))
+			continue;
+
+		if (btf_type_is_scalar(t)) {
+			if (reg->type != SCALAR_VALUE) {
+				verbose(env, "R%d is not a scalar\n", regno);
+				return -EINVAL;
+			}
+
+			if (is_kfunc_arg_constant(meta->btf, &args[i])) {
+				if (meta->arg_constant.found) {
+					verbose(env, "verifier internal error: only one constant argument permitted\n");
+					return -EFAULT;
+				}
+				if (!tnum_is_const(reg->var_off)) {
+					verbose(env, "R%d must be a known constant\n", regno);
+					return -EINVAL;
+				}
+				ret = mark_chain_precision(env, regno);
+				if (ret < 0)
+					return ret;
+				meta->arg_constant.found = true;
+				meta->arg_constant.value = reg->var_off.value;
+			} else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdonly_buf_size")) {
+				meta->r0_rdonly = true;
+				is_ret_buf_sz = true;
+			} else if (is_kfunc_arg_scalar_with_name(btf, &args[i], "rdwr_buf_size")) {
+				is_ret_buf_sz = true;
+			}
+
+			if (is_ret_buf_sz) {
+				if (meta->r0_size) {
+					verbose(env, "2 or more rdonly/rdwr_buf_size parameters for kfunc");
+					return -EINVAL;
+				}
+
+				if (!tnum_is_const(reg->var_off)) {
+					verbose(env, "R%d is not a const\n", regno);
+					return -EINVAL;
+				}
+
+				meta->r0_size = reg->var_off.value;
+				ret = mark_chain_precision(env, regno);
+				if (ret)
+					return ret;
+			}
+			continue;
+		}
+
+		if (!btf_type_is_ptr(t)) {
+			verbose(env, "Unrecognized arg#%d type %s\n", i, btf_type_str(t));
+			return -EINVAL;
+		}
+
+		if (reg->ref_obj_id) {
+			if (is_kfunc_release(meta) && meta->ref_obj_id) {
+				verbose(env, "verifier internal error: more than one arg with ref_obj_id R%d %u %u\n",
+					regno, reg->ref_obj_id,
+					meta->ref_obj_id);
+				return -EFAULT;
+			}
+			meta->ref_obj_id = reg->ref_obj_id;
+			if (is_kfunc_release(meta))
+				meta->release_regno = regno;
+		}
+
+		ref_t = btf_type_skip_modifiers(btf, t->type, &ref_id);
+		ref_tname = btf_name_by_offset(btf, ref_t->name_off);
+
+		kf_arg_type = get_kfunc_ptr_arg_type(env, meta, t, ref_t, ref_tname, args, i, nargs);
+		if (kf_arg_type < 0)
+			return kf_arg_type;
+
+		switch (kf_arg_type) {
+		case KF_ARG_PTR_TO_ALLOC_BTF_ID:
+		case KF_ARG_PTR_TO_BTF_ID:
+			if (!is_kfunc_trusted_args(meta))
+				break;
+			if (!reg->ref_obj_id) {
+				verbose(env, "R%d must be referenced\n", regno);
+				return -EINVAL;
+			}
+			fallthrough;
+		case KF_ARG_PTR_TO_CTX:
+			/* Trusted arguments have the same offset checks as release arguments */
+			arg_type |= OBJ_RELEASE;
+			break;
+		case KF_ARG_PTR_TO_KPTR:
+		case KF_ARG_PTR_TO_DYNPTR:
+		case KF_ARG_PTR_TO_LIST_HEAD:
+		case KF_ARG_PTR_TO_LIST_NODE:
+		case KF_ARG_PTR_TO_MEM:
+		case KF_ARG_PTR_TO_MEM_SIZE:
+			/* Trusted by default */
+			break;
+		default:
+			WARN_ON_ONCE(1);
+			return -EFAULT;
+		}
+
+		if (is_kfunc_release(meta) && reg->ref_obj_id)
+			arg_type |= OBJ_RELEASE;
+		ret = check_func_arg_reg_off(env, reg, regno, arg_type);
+		if (ret < 0)
+			return ret;
+
+		switch (kf_arg_type) {
+		case KF_ARG_PTR_TO_CTX:
+			if (reg->type != PTR_TO_CTX) {
+				verbose(env, "arg#%d expected pointer to ctx, but got %s\n", i, btf_type_str(t));
+				return -EINVAL;
+			}
+			break;
+		case KF_ARG_PTR_TO_ALLOC_BTF_ID:
+			if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+				verbose(env, "arg#%d expected pointer to allocated object\n", i);
+				return -EINVAL;
+			}
+			if (!reg->ref_obj_id) {
+				verbose(env, "allocated object must be referenced\n");
+				return -EINVAL;
+			}
+			if (meta->btf == btf_vmlinux &&
+			    meta->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+				meta->arg_obj_drop.btf = reg->btf;
+				meta->arg_obj_drop.btf_id = reg->btf_id;
+			}
+			break;
+		case KF_ARG_PTR_TO_KPTR:
+			if (reg->type != PTR_TO_MAP_VALUE) {
+				verbose(env, "arg#0 expected pointer to map value\n");
+				return -EINVAL;
+			}
+			ret = process_kf_arg_ptr_to_kptr(env, reg, ref_t, ref_tname, meta, i);
+			if (ret < 0)
+				return ret;
+			break;
+		case KF_ARG_PTR_TO_DYNPTR:
+			if (reg->type != PTR_TO_STACK) {
+				verbose(env, "arg#%d expected pointer to stack\n", i);
+				return -EINVAL;
+			}
+
+			if (!is_dynptr_reg_valid_init(env, reg)) {
+				verbose(env, "arg#%d pointer type %s %s must be valid and initialized\n",
+					i, btf_type_str(ref_t), ref_tname);
+				return -EINVAL;
+			}
+
+			if (!is_dynptr_type_expected(env, reg, ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_LOCAL)) {
+				verbose(env, "arg#%d pointer type %s %s points to unsupported dynamic pointer type\n",
+					i, btf_type_str(ref_t), ref_tname);
+				return -EINVAL;
+			}
+			break;
+		case KF_ARG_PTR_TO_LIST_HEAD:
+			if (reg->type != PTR_TO_MAP_VALUE &&
+			    reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+				verbose(env, "arg#%d expected pointer to map value or allocated object\n", i);
+				return -EINVAL;
+			}
+			if (reg->type == (PTR_TO_BTF_ID | MEM_ALLOC) && !reg->ref_obj_id) {
+				verbose(env, "allocated object must be referenced\n");
+				return -EINVAL;
+			}
+			ret = process_kf_arg_ptr_to_list_head(env, reg, regno, meta);
+			if (ret < 0)
+				return ret;
+			break;
+		case KF_ARG_PTR_TO_LIST_NODE:
+			if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC)) {
+				verbose(env, "arg#%d expected pointer to allocated object\n", i);
+				return -EINVAL;
+			}
+			if (!reg->ref_obj_id) {
+				verbose(env, "allocated object must be referenced\n");
+				return -EINVAL;
+			}
+			ret = process_kf_arg_ptr_to_list_node(env, reg, regno, meta);
+			if (ret < 0)
+				return ret;
+			break;
+		case KF_ARG_PTR_TO_BTF_ID:
+			/* Only base_type is checked, further checks are done here */
+			if (reg->type != PTR_TO_BTF_ID &&
+			    (!reg2btf_ids[base_type(reg->type)] || type_flag(reg->type))) {
+				verbose(env, "arg#%d expected pointer to btf or socket\n", i);
+				return -EINVAL;
+			}
+			ret = process_kf_arg_ptr_to_btf_id(env, reg, ref_t, ref_tname, ref_id, meta, i);
+			if (ret < 0)
+				return ret;
+			break;
+		case KF_ARG_PTR_TO_MEM:
+			resolve_ret = btf_resolve_size(btf, ref_t, &type_size);
+			if (IS_ERR(resolve_ret)) {
+				verbose(env, "arg#%d reference type('%s %s') size cannot be determined: %ld\n",
+					i, btf_type_str(ref_t), ref_tname, PTR_ERR(resolve_ret));
+				return -EINVAL;
+			}
+			ret = check_mem_reg(env, reg, regno, type_size);
+			if (ret < 0)
+				return ret;
+			break;
+		case KF_ARG_PTR_TO_MEM_SIZE:
+			ret = check_kfunc_mem_size_reg(env, &regs[regno + 1], regno + 1);
+			if (ret < 0) {
+				verbose(env, "arg#%d arg#%d memory, len pair leads to invalid memory access\n", i, i + 1);
+				return ret;
+			}
+			/* Skip next '__sz' argument */
+			i++;
+			break;
+		}
+	}
+
+	if (is_kfunc_release(meta) && !meta->release_regno) {
+		verbose(env, "release kernel function %s expects refcounted PTR_TO_BTF_ID\n",
+			func_name);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static int check_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 			    int *insn_idx_p)
 {
 	const struct btf_type *t, *func, *func_proto, *ptr_type;
 	struct bpf_reg_state *regs = cur_regs(env);
-	struct bpf_kfunc_arg_meta meta = { 0 };
 	const char *func_name, *ptr_type_name;
+	struct bpf_kfunc_call_arg_meta meta;
 	u32 i, nargs, func_id, ptr_type_id;
 	int err, insn_idx = *insn_idx_p;
 	const struct btf_param *args;
 	struct btf *desc_btf;
 	u32 *kfunc_flags;
-	bool acq;
 
 	/* skip for now, but return error when we find this in fixup_kfunc_call */
 	if (!insn->imm)
···
 			func_name);
 		return -EACCES;
 	}
-	if (*kfunc_flags & KF_DESTRUCTIVE && !capable(CAP_SYS_BOOT)) {
-		verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capabilities\n");
+
+	/* Prepare kfunc call metadata */
+	memset(&meta, 0, sizeof(meta));
+	meta.btf = desc_btf;
+	meta.func_id = func_id;
+	meta.kfunc_flags = *kfunc_flags;
+	meta.func_proto = func_proto;
+	meta.func_name = func_name;
+
+	if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) {
+		verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n");
 		return -EACCES;
 	}
 
-	acq = *kfunc_flags & KF_ACQUIRE;
-
-	meta.flags = *kfunc_flags;
+	if (is_kfunc_sleepable(&meta) && !env->prog->aux->sleepable) {
+		verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
+		return -EACCES;
+	}
 
 	/* Check the arguments */
-	err = btf_check_kfunc_arg_match(env, desc_btf, func_id, regs, &meta);
+	err = check_kfunc_args(env, &meta);
 	if (err < 0)
 		return err;
 	/* In case of release function, we get register number of refcounted
-	 * PTR_TO_BTF_ID back from btf_check_kfunc_arg_match, do the release now
+	 * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
 	 */
-	if (err) {
-		err = release_reference(env, regs[err].ref_obj_id);
+	if (meta.release_regno) {
+		err = release_reference(env, regs[meta.release_regno].ref_obj_id);
 		if (err) {
 			verbose(env, "kfunc %s#%d reference has not been acquired before\n",
 				func_name, func_id);
···
 	/* Check return type */
 	t = btf_type_skip_modifiers(desc_btf, func_proto->type, NULL);
 
-	if (acq && !btf_type_is_struct_ptr(desc_btf, t)) {
-		verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
-		return -EINVAL;
+	if (is_kfunc_acquire(&meta) && !btf_type_is_struct_ptr(meta.btf, t)) {
+		/* Only exception is bpf_obj_new_impl */
+		if (meta.btf != btf_vmlinux || meta.func_id != special_kfunc_list[KF_bpf_obj_new_impl]) {
+			verbose(env, "acquire kernel function does not return PTR_TO_BTF_ID\n");
+			return -EINVAL;
+		}
 	}
 
 	if (btf_type_is_scalar(t)) {
 		mark_reg_unknown(env, regs, BPF_REG_0);
 		mark_btf_func_reg_size(env, BPF_REG_0, t->size);
 	} else if (btf_type_is_ptr(t)) {
-		ptr_type = btf_type_skip_modifiers(desc_btf, t->type,
-						   &ptr_type_id);
-		if (!btf_type_is_struct(ptr_type)) {
+		ptr_type = btf_type_skip_modifiers(desc_btf, t->type, &ptr_type_id);
+
+		if (meta.btf == btf_vmlinux && btf_id_set_contains(&special_kfunc_set, meta.func_id)) {
+			if (meta.func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
+				const struct btf_type *ret_t;
+				struct btf *ret_btf;
+				u32 ret_btf_id;
+
+				if (((u64)(u32)meta.arg_constant.value) != meta.arg_constant.value) {
+					verbose(env, "local type ID argument must be in range [0, U32_MAX]\n");
+					return -EINVAL;
+				}
+
+				ret_btf = env->prog->aux->btf;
+				ret_btf_id = meta.arg_constant.value;
+
+				/* This may be NULL due to user not supplying a BTF */
+				if (!ret_btf) {
+					verbose(env, "bpf_obj_new requires prog BTF\n");
+					return -EINVAL;
+				}
+
+				ret_t = btf_type_by_id(ret_btf, ret_btf_id);
+				if (!ret_t || !__btf_type_is_struct(ret_t)) {
+					verbose(env, "bpf_obj_new type ID argument must be of a struct\n");
+					return -EINVAL;
+				}
+
+				mark_reg_known_zero(env, regs, BPF_REG_0);
+				regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
+				regs[BPF_REG_0].btf = ret_btf;
+				regs[BPF_REG_0].btf_id = ret_btf_id;
+
+				env->insn_aux_data[insn_idx].obj_new_size = ret_t->size;
+				env->insn_aux_data[insn_idx].kptr_struct_meta =
+					btf_find_struct_meta(ret_btf, ret_btf_id);
+			} else if (meta.func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+				env->insn_aux_data[insn_idx].kptr_struct_meta =
+					btf_find_struct_meta(meta.arg_obj_drop.btf,
+							     meta.arg_obj_drop.btf_id);
+			} else if (meta.func_id == special_kfunc_list[KF_bpf_list_pop_front] ||
+				   meta.func_id == special_kfunc_list[KF_bpf_list_pop_back]) {
+				struct btf_field *field = meta.arg_list_head.field;
+
+				mark_reg_known_zero(env, regs, BPF_REG_0);
+				regs[BPF_REG_0].type = PTR_TO_BTF_ID | MEM_ALLOC;
+				regs[BPF_REG_0].btf = field->list_head.btf;
+				regs[BPF_REG_0].btf_id = field->list_head.value_btf_id;
+				regs[BPF_REG_0].off = field->list_head.node_offset;
+			} else {
+				verbose(env, "kernel function %s unhandled dynamic return type\n",
+					meta.func_name);
+				return -EFAULT;
+			}
+		} else if (!__btf_type_is_struct(ptr_type)) {
 			if (!meta.r0_size) {
 				ptr_type_name = btf_name_by_offset(desc_btf,
 								   ptr_type->name_off);
···
 			regs[BPF_REG_0].type = PTR_TO_BTF_ID;
 			regs[BPF_REG_0].btf_id = ptr_type_id;
 		}
-		if (*kfunc_flags & KF_RET_NULL) {
+
+		if (is_kfunc_ret_null(&meta)) {
 			regs[BPF_REG_0].type |= PTR_MAYBE_NULL;
 			/* For mark_ptr_or_null_reg, see 93c230e3f5bd6 */
 			regs[BPF_REG_0].id = ++env->id_gen;
 		}
 		mark_btf_func_reg_size(env, BPF_REG_0, sizeof(void *));
-		if (acq) {
+		if (is_kfunc_acquire(&meta)) {
 			int id = acquire_reference_state(env, insn_idx);
 
 			if (id < 0)
 				return id;
-			regs[BPF_REG_0].id = id;
+			if (is_kfunc_ret_null(&meta))
+				regs[BPF_REG_0].id = id;
 			regs[BPF_REG_0].ref_obj_id = id;
 		}
+		if (reg_may_point_to_spin_lock(&regs[BPF_REG_0]) && !regs[BPF_REG_0].id)
+			regs[BPF_REG_0].id = ++env->id_gen;
 	} /* else { add_kfunc_call() ensures it is btf_type_is_void(t) } */
 
 	nargs = btf_type_vlen(func_proto);
···
 {
 	if (type_may_be_null(reg->type) && reg->id == id &&
 	    !WARN_ON_ONCE(!reg->id)) {
-		if (WARN_ON_ONCE(reg->smin_value || reg->smax_value ||
-				 !tnum_equals_const(reg->var_off, 0) ||
-				 reg->off)) {
-			/* Old offset (both fixed and variable parts) should
-			 * have been known-zero, because we don't allow pointer
-			 * arithmetic on pointers that might be NULL. If we
-			 * see this happening, don't convert the register.
-			 */
+		/* Old offset (both fixed and variable parts) should have been
+		 * known-zero, because we don't allow pointer arithmetic on
+		 * pointers that might be NULL. If we see this happening, don't
+		 * convert the register.
+		 *
+		 * But in some cases, some helpers that return local kptrs
+		 * advance offset for the returned pointer. In those cases, it
+		 * is fine to expect to see reg->off.
+		 */
+		if (WARN_ON_ONCE(reg->smin_value || reg->smax_value || !tnum_equals_const(reg->var_off, 0)))
 			return;
-		}
+		if (reg->type != (PTR_TO_BTF_ID | MEM_ALLOC | PTR_MAYBE_NULL) && WARN_ON_ONCE(reg->off))
+			return;
 		if (is_null) {
 			reg->type = SCALAR_VALUE;
 			/* We don't need id and ref_obj_id from this point
···
 	    insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) {
 		dst_reg->type = PTR_TO_MAP_VALUE;
 		dst_reg->off = aux->map_off;
-		if (btf_record_has_field(map->record, BPF_SPIN_LOCK))
-			dst_reg->id = ++env->id_gen;
+		WARN_ON_ONCE(map->max_entries != 1);
+		/* We want reg->id to be same (0) as map_value is not distinct */
 	} else if (insn->src_reg == BPF_PSEUDO_MAP_FD ||
 		   insn->src_reg == BPF_PSEUDO_MAP_IDX) {
 		dst_reg->type = CONST_PTR_TO_MAP;
···
 		return err;
 	}
 
-	if (env->cur_state->active_spin_lock) {
+	if (env->cur_state->active_lock.ptr) {
 		verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_spin_lock-ed region\n");
 		return -EINVAL;
 	}
···
 	if (old->speculative && !cur->speculative)
 		return false;
 
-	if (old->active_spin_lock != cur->active_spin_lock)
+	if (old->active_lock.ptr != cur->active_lock.ptr ||
+	    old->active_lock.id != cur->active_lock.id)
 		return false;
 
 	/* for states to be equal callsites have to be the same
···
 					return -EINVAL;
 				}
 
-				if (env->cur_state->active_spin_lock &&
-				    (insn->src_reg == BPF_PSEUDO_CALL ||
-				     insn->imm != BPF_FUNC_spin_unlock)) {
-					verbose(env, "function calls are not allowed while holding a lock\n");
-					return -EINVAL;
+				if (env->cur_state->active_lock.ptr) {
+					if ((insn->src_reg == BPF_REG_0 && insn->imm != BPF_FUNC_spin_unlock) ||
+					    (insn->src_reg == BPF_PSEUDO_CALL) ||
+					    (insn->src_reg == BPF_PSEUDO_KFUNC_CALL &&
+					     (insn->off != 0 || !is_bpf_list_api_kfunc(insn->imm)))) {
+						verbose(env, "function calls are not allowed while holding a lock\n");
+						return -EINVAL;
+					}
 				}
 				if (insn->src_reg == BPF_PSEUDO_CALL)
 					err = check_func_call(env, insn, &env->insn_idx);
···
 					return -EINVAL;
 				}
 
-				if (env->cur_state->active_spin_lock) {
+				if (env->cur_state->active_lock.ptr) {
 					verbose(env, "bpf_spin_unlock is missing\n");
 					return -EINVAL;
 				}
···
 			break;
 		case PTR_TO_BTF_ID:
 		case PTR_TO_BTF_ID | PTR_UNTRUSTED:
+		/* PTR_TO_BTF_ID | MEM_ALLOC always has a valid lifetime, unlike
+		 * PTR_TO_BTF_ID, and an active ref_obj_id, but the same cannot
+		 * be said once it is marked PTR_UNTRUSTED, hence we must handle
+		 * any faults for loads into such types. BPF_WRITE is disallowed
+		 * for this case.
+		 */
+		case PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED:
 			if (type == BPF_READ) {
 				insn->code = BPF_LDX | BPF_PROBE_MEM |
 					BPF_SIZE((insn)->code);
···
 	return err;
 }
 
-static int fixup_kfunc_call(struct bpf_verifier_env *env,
-			    struct bpf_insn *insn)
+static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			    struct bpf_insn *insn_buf, int insn_idx, int *cnt)
 {
 	const struct bpf_kfunc_desc *desc;
 
···
 		return -EFAULT;
 	}
 
+	*cnt = 0;
 	insn->imm = desc->imm;
+	if (insn->off)
+		return 0;
+	if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl]) {
+		struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+		struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
+		u64 obj_new_size = env->insn_aux_data[insn_idx].obj_new_size;
 
+		insn_buf[0] = BPF_MOV64_IMM(BPF_REG_1, obj_new_size);
+		insn_buf[1] = addr[0];
+		insn_buf[2] = addr[1];
+		insn_buf[3] = *insn;
+		*cnt = 4;
+	} else if (desc->func_id == special_kfunc_list[KF_bpf_obj_drop_impl]) {
+		struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+		struct bpf_insn addr[2] = { BPF_LD_IMM64(BPF_REG_2, (long)kptr_struct_meta) };
+
+		insn_buf[0] = addr[0];
+		insn_buf[1] = addr[1];
+		insn_buf[2] = *insn;
+		*cnt = 3;
+	}
 	return 0;
 }
 
···
 		if (insn->src_reg == BPF_PSEUDO_CALL)
 			continue;
 		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
-			ret = fixup_kfunc_call(env, insn);
+			ret = fixup_kfunc_call(env, insn, insn_buf, i + delta, &cnt);
 			if (ret)
 				return ret;
+			if (cnt == 0)
+				continue;
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta	 += cnt - 1;
+			env->prog = prog = new_prog;
+			insn	  = new_prog->insnsi + i + delta;
 			continue;
 		}
 

tools/testing/selftests/bpf/DENYLIST.aarch64

···
 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

···
 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/bpf_experimental.h

···
+#ifndef __BPF_EXPERIMENTAL__
+#define __BPF_EXPERIMENTAL__
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+
+#define __contains(name, node) __attribute__((btf_decl_tag("contains:" #name ":" #node)))
+
+/* Description
+ *	Allocates an object of the type represented by 'local_type_id' in
+ *	program BTF. User may use the bpf_core_type_id_local macro to pass the
+ *	type ID of a struct in program BTF.
+ *
+ *	The 'local_type_id' parameter must be a known constant.
+ *	The 'meta' parameter is a hidden argument that is ignored.
+ * Returns
+ *	A pointer to an object of the type corresponding to the passed in
+ *	'local_type_id', or NULL on failure.
+ */
+extern void *bpf_obj_new_impl(__u64 local_type_id, void *meta) __ksym;
+
+/* Convenience macro to wrap over bpf_obj_new_impl */
+#define bpf_obj_new(type) ((type *)bpf_obj_new_impl(bpf_core_type_id_local(type), NULL))
+
+/* Description
+ *	Free an allocated object. All fields of the object that require
+ *	destruction will be destructed before the storage is freed.
+ *
+ *	The 'meta' parameter is a hidden argument that is ignored.
+ * Returns
+ *	Void.
+ */
+extern void bpf_obj_drop_impl(void *kptr, void *meta) __ksym;
+
+/* Convenience macro to wrap over bpf_obj_drop_impl */
+#define bpf_obj_drop(kptr) bpf_obj_drop_impl(kptr, NULL)
+
+/* Description
+ *	Add a new entry to the beginning of the BPF linked list.
+ * Returns
+ *	Void.
+ */
+extern void bpf_list_push_front(struct bpf_list_head *head, struct bpf_list_node *node) __ksym;
+
+/* Description
+ *	Add a new entry to the end of the BPF linked list.
+ * Returns
+ *	Void.
+ */
+extern void bpf_list_push_back(struct bpf_list_head *head, struct bpf_list_node *node) __ksym;
+
+/* Description
+ *	Remove the entry at the beginning of the BPF linked list.
+ * Returns
+ *	Pointer to bpf_list_node of deleted entry, or NULL if list is empty.
+ */
+extern struct bpf_list_node *bpf_list_pop_front(struct bpf_list_head *head) __ksym;
+
+/* Description
+ *	Remove the entry at the end of the BPF linked list.
+ * Returns
+ *	Pointer to bpf_list_node of deleted entry, or NULL if list is empty.
+ */
+extern struct bpf_list_node *bpf_list_pop_back(struct bpf_list_head *head) __ksym;
+
+#endif

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

···
 	 "arg#0 pointer type STRUCT bpf_dynptr_kern points to unsupported dynamic pointer type", 0},
 	{"not_valid_dynptr",
 	 "arg#0 pointer type STRUCT bpf_dynptr_kern must be valid and initialized", 0},
-	{"not_ptr_to_stack", "arg#0 pointer type STRUCT bpf_dynptr_kern not to stack", 0},
+	{"not_ptr_to_stack", "arg#0 expected pointer to stack", 0},
 	{"dynptr_data_null", NULL, -EBADMSG},
 };
 

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

···
+// 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)
+/* FIXME
+	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 "_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(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
+/* FIXME
+	{ "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" },
+/* FIXME
+	{ "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" },
+/* FIXME
+	{ "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");
+	/* FIXME:
+	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");
+	/* FIXME:
+	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");
+	/* FIXME:
+	if (!leave_in_map)
+		clear_fields(skel->maps.data_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);
+}

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

···
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include <network_helpers.h>
+
+#include "test_spin_lock.skel.h"
+#include "test_spin_lock_fail.skel.h"
+
+static char log_buf[1024 * 1024];
+
+static struct {
+	const char *prog_name;
+	const char *err_msg;
+} spin_lock_fail_tests[] = {
+	{ "lock_id_kptr_preserve",
+	  "5: (bf) r1 = r0                       ; R0_w=ptr_foo(id=2,ref_obj_id=2,off=0,imm=0) "
+	  "R1_w=ptr_foo(id=2,ref_obj_id=2,off=0,imm=0) refs=2\n6: (85) call bpf_this_cpu_ptr#154\n"
+	  "R1 type=ptr_ expected=percpu_ptr_" },
+	{ "lock_id_global_zero",
+	  "; R1_w=map_value(off=0,ks=4,vs=4,imm=0)\n2: (85) call bpf_this_cpu_ptr#154\n"
+	  "R1 type=map_value expected=percpu_ptr_" },
+	{ "lock_id_mapval_preserve",
+	  "8: (bf) r1 = r0                       ; R0_w=map_value(id=1,off=0,ks=4,vs=8,imm=0) "
+	  "R1_w=map_value(id=1,off=0,ks=4,vs=8,imm=0)\n9: (85) call bpf_this_cpu_ptr#154\n"
+	  "R1 type=map_value expected=percpu_ptr_" },
+	{ "lock_id_innermapval_preserve",
+	  "13: (bf) r1 = r0                      ; R0=map_value(id=2,off=0,ks=4,vs=8,imm=0) "
+	  "R1_w=map_value(id=2,off=0,ks=4,vs=8,imm=0)\n14: (85) call bpf_this_cpu_ptr#154\n"
+	  "R1 type=map_value expected=percpu_ptr_" },
+	{ "lock_id_mismatch_kptr_kptr", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_kptr_global", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_kptr_mapval", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_kptr_innermapval", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_global_global", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_global_kptr", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_global_mapval", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_global_innermapval", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_mapval_mapval", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_mapval_kptr", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_mapval_global", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_mapval_innermapval", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_innermapval_innermapval1", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_innermapval_innermapval2", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_innermapval_kptr", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_innermapval_global", "bpf_spin_unlock of different lock" },
+	{ "lock_id_mismatch_innermapval_mapval", "bpf_spin_unlock of different lock" },
+};
+
+static void test_spin_lock_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 test_spin_lock_fail *skel;
+	struct bpf_program *prog;
+	int ret;
+
+	skel = test_spin_lock_fail__open_opts(&opts);
+	if (!ASSERT_OK_PTR(skel, "test_spin_lock_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 = test_spin_lock_fail__load(skel);
+	if (!ASSERT_ERR(ret, "test_spin_lock_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:
+	test_spin_lock_fail__destroy(skel);
+}
+
+static void *spin_lock_thread(void *arg)
+{
+	int err, prog_fd = *(u32 *) arg;
+	LIBBPF_OPTS(bpf_test_run_opts, topts,
+		.data_in = &pkt_v4,
+		.data_size_in = sizeof(pkt_v4),
+		.repeat = 10000,
+	);
+
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	ASSERT_OK(err, "test_run");
+	ASSERT_OK(topts.retval, "test_run retval");
+	pthread_exit(arg);
+}
+
+void test_spin_lock_success(void)
+{
+	struct test_spin_lock *skel;
+	pthread_t thread_id[4];
+	int prog_fd, i;
+	void *ret;
+
+	skel = test_spin_lock__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_spin_lock__open_and_load"))
+		return;
+	prog_fd = bpf_program__fd(skel->progs.bpf_spin_lock_test);
+	for (i = 0; i < 4; i++) {
+		int err;
+
+		err = pthread_create(&thread_id[i], NULL, &spin_lock_thread, &prog_fd);
+		if (!ASSERT_OK(err, "pthread_create"))
+			goto end;
+	}
+
+	for (i = 0; i < 4; i++) {
+		if (!ASSERT_OK(pthread_join(thread_id[i], &ret), "pthread_join"))
+			goto end;
+		if (!ASSERT_EQ(ret, &prog_fd, "ret == prog_fd"))
+			goto end;
+	}
+end:
+	test_spin_lock__destroy(skel);
+}
+
+void test_spin_lock(void)
+{
+	int i;
+
+	test_spin_lock_success();
+
+	for (i = 0; i < ARRAY_SIZE(spin_lock_fail_tests); i++) {
+		if (!test__start_subtest(spin_lock_fail_tests[i].prog_name))
+			continue;
+		test_spin_lock_fail_prog(spin_lock_fail_tests[i].prog_name,
+					 spin_lock_fail_tests[i].err_msg);
+	}
+}

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

···
-// SPDX-License-Identifier: GPL-2.0
-#include <test_progs.h>
-#include <network_helpers.h>
-
-static void *spin_lock_thread(void *arg)
-{
-	int err, prog_fd = *(u32 *) arg;
-	LIBBPF_OPTS(bpf_test_run_opts, topts,
-		.data_in = &pkt_v4,
-		.data_size_in = sizeof(pkt_v4),
-		.repeat = 10000,
-	);
-
-	err = bpf_prog_test_run_opts(prog_fd, &topts);
-	ASSERT_OK(err, "test_run");
-	ASSERT_OK(topts.retval, "test_run retval");
-	pthread_exit(arg);
-}
-
-void test_spinlock(void)
-{
-	const char *file = "./test_spin_lock.bpf.o";
-	pthread_t thread_id[4];
-	struct bpf_object *obj = NULL;
-	int prog_fd;
-	int err = 0, i;
-	void *ret;
-
-	err = bpf_prog_test_load(file, BPF_PROG_TYPE_CGROUP_SKB, &obj, &prog_fd);
-	if (CHECK_FAIL(err)) {
-		printf("test_spin_lock:bpf_prog_test_load errno %d\n", errno);
-		goto close_prog;
-	}
-	for (i = 0; i < 4; i++)
-		if (CHECK_FAIL(pthread_create(&thread_id[i], NULL,
-					      &spin_lock_thread, &prog_fd)))
-			goto close_prog;
-
-	for (i = 0; i < 4; i++)
-		if (CHECK_FAIL(pthread_join(thread_id[i], &ret) ||
-			       ret != (void *)&prog_fd))
-			goto close_prog;
-close_prog:
-	bpf_object__close(obj);
-}

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)
+{
+	/* FIXME:
+	 * return test_list_push_pop(&glock, &ghead);
+	 */
+	return 0;
+}
+
+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;
+
+	/* FIXME:
+	ret = list_push_pop_multiple(&glock, &ghead, false);
+	if (ret)
+		return ret;
+	return list_push_pop_multiple(&glock, &ghead, true);
+	*/
+	return 0;
+}
+
+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)
+{
+	/* FIXME
+	return test_list_in_list(&glock, &ghead);
+	*/
+	return 0;
+}
+
+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,
+	},
+};
+
+/* FIXME
+#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

tools/testing/selftests/bpf/progs/linked_list_fail.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"
+
+#include "linked_list.h"
+
+#define INIT                                                  \
+	struct map_value *v, *v2, *iv, *iv2;                  \
+	struct foo *f, *f1, *f2;                              \
+	struct bar *b;                                        \
+	void *map;                                            \
+                                                              \
+	map = bpf_map_lookup_elem(&map_of_maps, &(int){ 0 }); \
+	if (!map)                                             \
+		return 0;                                     \
+	v = bpf_map_lookup_elem(&array_map, &(int){ 0 });     \
+	if (!v)                                               \
+		return 0;                                     \
+	v2 = bpf_map_lookup_elem(&array_map, &(int){ 0 });    \
+	if (!v2)                                              \
+		return 0;                                     \
+	iv = bpf_map_lookup_elem(map, &(int){ 0 });           \
+	if (!iv)                                              \
+		return 0;                                     \
+	iv2 = bpf_map_lookup_elem(map, &(int){ 0 });          \
+	if (!iv2)                                             \
+		return 0;                                     \
+	f = bpf_obj_new(typeof(*f));                          \
+	if (!f)                                               \
+		return 0;                                     \
+	f1 = f;                                               \
+	f2 = bpf_obj_new(typeof(*f2));                        \
+	if (!f2) {                                            \
+		bpf_obj_drop(f1);                             \
+		return 0;                                     \
+	}                                                     \
+	b = bpf_obj_new(typeof(*b));                          \
+	if (!b) {                                             \
+		bpf_obj_drop(f2);                             \
+		bpf_obj_drop(f1);                             \
+		return 0;                                     \
+	}
+
+#define CHECK(test, op, hexpr)                              \
+	SEC("?tc")                                          \
+	int test##_missing_lock_##op(void *ctx)             \
+	{                                                   \
+		INIT;                                       \
+		void (*p)(void *) = (void *)&bpf_list_##op; \
+		p(hexpr);                                   \
+		return 0;                                   \
+	}
+
+CHECK(kptr, push_front, &f->head);
+CHECK(kptr, push_back, &f->head);
+CHECK(kptr, pop_front, &f->head);
+CHECK(kptr, pop_back, &f->head);
+
+/* FIXME
+CHECK(global, push_front, &ghead);
+CHECK(global, push_back, &ghead);
+CHECK(global, pop_front, &ghead);
+CHECK(global, pop_back, &ghead);
+*/
+
+CHECK(map, push_front, &v->head);
+CHECK(map, push_back, &v->head);
+CHECK(map, pop_front, &v->head);
+CHECK(map, pop_back, &v->head);
+
+CHECK(inner_map, push_front, &iv->head);
+CHECK(inner_map, push_back, &iv->head);
+CHECK(inner_map, pop_front, &iv->head);
+CHECK(inner_map, pop_back, &iv->head);
+
+#undef CHECK
+
+#define CHECK(test, op, lexpr, hexpr)                       \
+	SEC("?tc")                                          \
+	int test##_incorrect_lock_##op(void *ctx)           \
+	{                                                   \
+		INIT;                                       \
+		void (*p)(void *) = (void *)&bpf_list_##op; \
+		bpf_spin_lock(lexpr);                       \
+		p(hexpr);                                   \
+		return 0;                                   \
+	}
+
+#define CHECK_OP(op)                                           \
+	CHECK(kptr_kptr, op, &f1->lock, &f2->head);            \
+	CHECK(kptr_map, op, &f1->lock, &v->head);              \
+	CHECK(kptr_inner_map, op, &f1->lock, &iv->head);       \
+                                                               \
+	CHECK(map_map, op, &v->lock, &v2->head);               \
+	CHECK(map_kptr, op, &v->lock, &f2->head);              \
+	CHECK(map_inner_map, op, &v->lock, &iv->head);         \
+                                                               \
+	CHECK(inner_map_inner_map, op, &iv->lock, &iv2->head); \
+	CHECK(inner_map_kptr, op, &iv->lock, &f2->head);       \
+	CHECK(inner_map_map, op, &iv->lock, &v->head);
+
+CHECK_OP(push_front);
+CHECK_OP(push_back);
+CHECK_OP(pop_front);
+CHECK_OP(pop_back);
+
+#undef CHECK
+#undef CHECK_OP
+#undef INIT
+
+/* FIXME
+SEC("?kprobe/xyz")
+int map_compat_kprobe(void *ctx)
+{
+	bpf_list_push_front(&ghead, NULL);
+	return 0;
+}
+
+SEC("?kretprobe/xyz")
+int map_compat_kretprobe(void *ctx)
+{
+	bpf_list_push_front(&ghead, NULL);
+	return 0;
+}
+
+SEC("?tracepoint/xyz")
+int map_compat_tp(void *ctx)
+{
+	bpf_list_push_front(&ghead, NULL);
+	return 0;
+}
+
+SEC("?perf_event")
+int map_compat_perf(void *ctx)
+{
+	bpf_list_push_front(&ghead, NULL);
+	return 0;
+}
+
+SEC("?raw_tp/xyz")
+int map_compat_raw_tp(void *ctx)
+{
+	bpf_list_push_front(&ghead, NULL);
+	return 0;
+}
+
+SEC("?raw_tp.w/xyz")
+int map_compat_raw_tp_w(void *ctx)
+{
+	bpf_list_push_front(&ghead, NULL);
+	return 0;
+}
+*/
+
+SEC("?tc")
+int obj_type_id_oor(void *ctx)
+{
+	bpf_obj_new_impl(~0UL, NULL);
+	return 0;
+}
+
+SEC("?tc")
+int obj_new_no_composite(void *ctx)
+{
+	bpf_obj_new_impl(bpf_core_type_id_local(int), (void *)42);
+	return 0;
+}
+
+SEC("?tc")
+int obj_new_no_struct(void *ctx)
+{
+
+	bpf_obj_new(union { int data; unsigned udata; });
+	return 0;
+}
+
+SEC("?tc")
+int obj_drop_non_zero_off(void *ctx)
+{
+	void *f;
+
+	f = bpf_obj_new(struct foo);
+	if (!f)
+		return 0;
+	bpf_obj_drop(f+1);
+	return 0;
+}
+
+SEC("?tc")
+int new_null_ret(void *ctx)
+{
+	return bpf_obj_new(struct foo)->data;
+}
+
+SEC("?tc")
+int obj_new_acq(void *ctx)
+{
+	bpf_obj_new(struct foo);
+	return 0;
+}
+
+SEC("?tc")
+int use_after_drop(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_obj_drop(f);
+	return f->data;
+}
+
+SEC("?tc")
+int ptr_walk_scalar(void *ctx)
+{
+	struct test1 {
+		struct test2 {
+			struct test2 *next;
+		} *ptr;
+	} *p;
+
+	p = bpf_obj_new(typeof(*p));
+	if (!p)
+		return 0;
+	bpf_this_cpu_ptr(p->ptr);
+	return 0;
+}
+
+SEC("?tc")
+int direct_read_lock(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	return *(int *)&f->lock;
+}
+
+SEC("?tc")
+int direct_write_lock(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	*(int *)&f->lock = 0;
+	return 0;
+}
+
+SEC("?tc")
+int direct_read_head(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	return *(int *)&f->head;
+}
+
+SEC("?tc")
+int direct_write_head(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	*(int *)&f->head = 0;
+	return 0;
+}
+
+SEC("?tc")
+int direct_read_node(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	return *(int *)&f->node;
+}
+
+SEC("?tc")
+int direct_write_node(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	*(int *)&f->node = 0;
+	return 0;
+}
+
+/* FIXME
+static __always_inline
+int write_after_op(void (*push_op)(void *head, void *node))
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	push_op(&ghead, &f->node);
+	f->data = 42;
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int write_after_push_front(void *ctx)
+{
+	return write_after_op((void *)bpf_list_push_front);
+}
+
+SEC("?tc")
+int write_after_push_back(void *ctx)
+{
+	return write_after_op((void *)bpf_list_push_back);
+}
+
+static __always_inline
+int use_after_unlock(void (*op)(void *head, void *node))
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	f->data = 42;
+	op(&ghead, &f->node);
+	bpf_spin_unlock(&glock);
+
+	return f->data;
+}
+
+SEC("?tc")
+int use_after_unlock_push_front(void *ctx)
+{
+	return use_after_unlock((void *)bpf_list_push_front);
+}
+
+SEC("?tc")
+int use_after_unlock_push_back(void *ctx)
+{
+	return use_after_unlock((void *)bpf_list_push_back);
+}
+
+static __always_inline
+int list_double_add(void (*op)(void *head, void *node))
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	op(&ghead, &f->node);
+	op(&ghead, &f->node);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int double_push_front(void *ctx)
+{
+	return list_double_add((void *)bpf_list_push_front);
+}
+
+SEC("?tc")
+int double_push_back(void *ctx)
+{
+	return list_double_add((void *)bpf_list_push_back);
+}
+
+SEC("?tc")
+int no_node_value_type(void *ctx)
+{
+	void *p;
+
+	p = bpf_obj_new(struct { int data; });
+	if (!p)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front(&ghead, p);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int incorrect_value_type(void *ctx)
+{
+	struct bar *b;
+
+	b = bpf_obj_new(typeof(*b));
+	if (!b)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front(&ghead, &b->node);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int incorrect_node_var_off(struct __sk_buff *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front(&ghead, (void *)&f->node + ctx->protocol);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int incorrect_node_off1(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front(&ghead, (void *)&f->node + 1);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int incorrect_node_off2(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front(&ghead, &f->node2);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int no_head_type(void *ctx)
+{
+	void *p;
+
+	p = bpf_obj_new(typeof(struct { int data; }));
+	if (!p)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front(p, NULL);
+	bpf_spin_lock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int incorrect_head_var_off1(struct __sk_buff *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front((void *)&ghead + ctx->protocol, &f->node);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+
+SEC("?tc")
+int incorrect_head_var_off2(struct __sk_buff *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_spin_lock(&glock);
+	bpf_list_push_front((void *)&f->head + ctx->protocol, &f->node);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+*/
+
+SEC("?tc")
+int incorrect_head_off1(void *ctx)
+{
+	struct foo *f;
+	struct bar *b;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	b = bpf_obj_new(typeof(*b));
+	if (!b) {
+		bpf_obj_drop(f);
+		return 0;
+	}
+
+	bpf_spin_lock(&f->lock);
+	bpf_list_push_front((void *)&f->head + 1, &b->node);
+	bpf_spin_unlock(&f->lock);
+
+	return 0;
+}
+
+/* FIXME
+SEC("?tc")
+int incorrect_head_off2(void *ctx)
+{
+	struct foo *f;
+	struct bar *b;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+
+	bpf_spin_lock(&glock);
+	bpf_list_push_front((void *)&ghead + 1, &f->node);
+	bpf_spin_unlock(&glock);
+
+	return 0;
+}
+*/
+
+static __always_inline
+int pop_ptr_off(void *(*op)(void *head))
+{
+	struct {
+		struct bpf_list_head head __contains(foo, node2);
+		struct bpf_spin_lock lock;
+	} *p;
+	struct bpf_list_node *n;
+
+	p = bpf_obj_new(typeof(*p));
+	if (!p)
+		return 0;
+	bpf_spin_lock(&p->lock);
+	n = op(&p->head);
+	bpf_spin_unlock(&p->lock);
+
+	bpf_this_cpu_ptr(n);
+	return 0;
+}
+
+SEC("?tc")
+int pop_front_off(void *ctx)
+{
+	return pop_ptr_off((void *)bpf_list_pop_front);
+}
+
+SEC("?tc")
+int pop_back_off(void *ctx)
+{
+	return pop_ptr_off((void *)bpf_list_pop_back);
+}
+
+char _license[] SEC("license") = "GPL";

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

···
 
 #define CREDIT_PER_NS(delta, rate) (((delta) * rate) >> 20)
 
-SEC("tc")
-int bpf_sping_lock_test(struct __sk_buff *skb)
+SEC("cgroup_skb/ingress")
+int bpf_spin_lock_test(struct __sk_buff *skb)
 {
 	volatile int credit = 0, max_credit = 100, pkt_len = 64;
 	struct hmap_elem zero = {}, *val;

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

···
+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_experimental.h"
+
+struct foo {
+	struct bpf_spin_lock lock;
+	int data;
+};
+
+struct array_map {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__type(key, int);
+	__type(value, struct foo);
+	__uint(max_entries, 1);
+} array_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] = &array_map,
+	},
+};
+
+SEC(".data.A") struct bpf_spin_lock lockA;
+SEC(".data.B") struct bpf_spin_lock lockB;
+
+SEC("?tc")
+int lock_id_kptr_preserve(void *ctx)
+{
+	struct foo *f;
+
+	f = bpf_obj_new(typeof(*f));
+	if (!f)
+		return 0;
+	bpf_this_cpu_ptr(f);
+	return 0;
+}
+
+SEC("?tc")
+int lock_id_global_zero(void *ctx)
+{
+	bpf_this_cpu_ptr(&lockA);
+	return 0;
+}
+
+SEC("?tc")
+int lock_id_mapval_preserve(void *ctx)
+{
+	struct foo *f;
+	int key = 0;
+
+	f = bpf_map_lookup_elem(&array_map, &key);
+	if (!f)
+		return 0;
+	bpf_this_cpu_ptr(f);
+	return 0;
+}
+
+SEC("?tc")
+int lock_id_innermapval_preserve(void *ctx)
+{
+	struct foo *f;
+	int key = 0;
+	void *map;
+
+	map = bpf_map_lookup_elem(&map_of_maps, &key);
+	if (!map)
+		return 0;
+	f = bpf_map_lookup_elem(map, &key);
+	if (!f)
+		return 0;
+	bpf_this_cpu_ptr(f);
+	return 0;
+}
+
+#define CHECK(test, A, B)                                      \
+	SEC("?tc")                                             \
+	int lock_id_mismatch_##test(void *ctx)                 \
+	{                                                      \
+		struct foo *f1, *f2, *v, *iv;                  \
+		int key = 0;                                   \
+		void *map;                                     \
+                                                               \
+		map = bpf_map_lookup_elem(&map_of_maps, &key); \
+		if (!map)                                      \
+			return 0;                              \
+		iv = bpf_map_lookup_elem(map, &key);           \
+		if (!iv)                                       \
+			return 0;                              \
+		v = bpf_map_lookup_elem(&array_map, &key);     \
+		if (!v)                                        \
+			return 0;                              \
+		f1 = bpf_obj_new(typeof(*f1));                 \
+		if (!f1)                                       \
+			return 0;                              \
+		f2 = bpf_obj_new(typeof(*f2));                 \
+		if (!f2) {                                     \
+			bpf_obj_drop(f1);                      \
+			return 0;                              \
+		}                                              \
+		bpf_spin_lock(A);                              \
+		bpf_spin_unlock(B);                            \
+		return 0;                                      \
+	}
+
+CHECK(kptr_kptr, &f1->lock, &f2->lock);
+CHECK(kptr_global, &f1->lock, &lockA);
+CHECK(kptr_mapval, &f1->lock, &v->lock);
+CHECK(kptr_innermapval, &f1->lock, &iv->lock);
+
+CHECK(global_global, &lockA, &lockB);
+CHECK(global_kptr, &lockA, &f1->lock);
+CHECK(global_mapval, &lockA, &v->lock);
+CHECK(global_innermapval, &lockA, &iv->lock);
+
+SEC("?tc")
+int lock_id_mismatch_mapval_mapval(void *ctx)
+{
+	struct foo *f1, *f2;
+	int key = 0;
+
+	f1 = bpf_map_lookup_elem(&array_map, &key);
+	if (!f1)
+		return 0;
+	f2 = bpf_map_lookup_elem(&array_map, &key);
+	if (!f2)
+		return 0;
+
+	bpf_spin_lock(&f1->lock);
+	f1->data = 42;
+	bpf_spin_unlock(&f2->lock);
+
+	return 0;
+}
+
+CHECK(mapval_kptr, &v->lock, &f1->lock);
+CHECK(mapval_global, &v->lock, &lockB);
+CHECK(mapval_innermapval, &v->lock, &iv->lock);
+
+SEC("?tc")
+int lock_id_mismatch_innermapval_innermapval1(void *ctx)
+{
+	struct foo *f1, *f2;
+	int key = 0;
+	void *map;
+
+	map = bpf_map_lookup_elem(&map_of_maps, &key);
+	if (!map)
+		return 0;
+	f1 = bpf_map_lookup_elem(map, &key);
+	if (!f1)
+		return 0;
+	f2 = bpf_map_lookup_elem(map, &key);
+	if (!f2)
+		return 0;
+
+	bpf_spin_lock(&f1->lock);
+	f1->data = 42;
+	bpf_spin_unlock(&f2->lock);
+
+	return 0;
+}
+
+SEC("?tc")
+int lock_id_mismatch_innermapval_innermapval2(void *ctx)
+{
+	struct foo *f1, *f2;
+	int key = 0;
+	void *map;
+
+	map = bpf_map_lookup_elem(&map_of_maps, &key);
+	if (!map)
+		return 0;
+	f1 = bpf_map_lookup_elem(map, &key);
+	if (!f1)
+		return 0;
+	map = bpf_map_lookup_elem(&map_of_maps, &key);
+	if (!map)
+		return 0;
+	f2 = bpf_map_lookup_elem(map, &key);
+	if (!f2)
+		return 0;
+
+	bpf_spin_lock(&f1->lock);
+	f1->data = 42;
+	bpf_spin_unlock(&f2->lock);
+
+	return 0;
+}
+
+CHECK(innermapval_kptr, &iv->lock, &f1->lock);
+CHECK(innermapval_global, &iv->lock, &lockA);
+CHECK(innermapval_mapval, &iv->lock, &v->lock);
+
+#undef CHECK
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/verifier/calls.c

···
 	},
 	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
 	.result = REJECT,
-	.errstr = "arg#0 pointer type STRUCT prog_test_ref_kfunc must point",
+	.errstr = "arg#0 expected pointer to btf or socket",
 	.fixup_kfunc_btf_id = {
 		{ "bpf_kfunc_call_test_acquire", 3 },
 		{ "bpf_kfunc_call_test_release", 5 },

tools/testing/selftests/bpf/verifier/ref_tracking.c

···
 	.kfunc = "bpf",
 	.expected_attach_type = BPF_LSM_MAC,
 	.flags = BPF_F_SLEEPABLE,
-	.errstr = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar",
+	.errstr = "arg#0 expected pointer to btf or socket",
 	.fixup_kfunc_btf_id = {
 		{ "bpf_lookup_user_key", 2 },
 		{ "bpf_key_put", 4 },
···
 	.kfunc = "bpf",
 	.expected_attach_type = BPF_LSM_MAC,
 	.flags = BPF_F_SLEEPABLE,
-	.errstr = "arg#0 pointer type STRUCT bpf_key must point to scalar, or struct with scalar",
+	.errstr = "arg#0 expected pointer to btf or socket",
 	.fixup_kfunc_btf_id = {
 		{ "bpf_lookup_system_key", 1 },
 		{ "bpf_key_put", 3 },