Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 20425 insertions, 0 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
new file mode 100644
index 0000000000..a7901ed358
--- /dev/null
+++ b/kernel/bpf/verifier.c
@@ -0,0 +1,20425 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
+ * Copyright (c) 2016 Facebook
+ * Copyright (c) 2018 Covalent IO, Inc. http://covalent.io
+ */
+#include <uapi/linux/btf.h>
+#include <linux/bpf-cgroup.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/bpf_verifier.h>
+#include <linux/filter.h>
+#include <net/netlink.h>
+#include <linux/file.h>
+#include <linux/vmalloc.h>
+#include <linux/stringify.h>
+#include <linux/bsearch.h>
+#include <linux/sort.h>
+#include <linux/perf_event.h>
+#include <linux/ctype.h>
+#include <linux/error-injection.h>
+#include <linux/bpf_lsm.h>
+#include <linux/btf_ids.h>
+#include <linux/poison.h>
+#include <linux/module.h>
+#include <linux/cpumask.h>
+#include <net/xdp.h>
+
+#include "disasm.h"
+
+static const struct bpf_verifier_ops * const bpf_verifier_ops[] = {
+#define BPF_PROG_TYPE(_id, _name, prog_ctx_type, kern_ctx_type) \
+	[_id] = & _name ## _verifier_ops,
+#define BPF_MAP_TYPE(_id, _ops)
+#define BPF_LINK_TYPE(_id, _name)
+#include <linux/bpf_types.h>
+#undef BPF_PROG_TYPE
+#undef BPF_MAP_TYPE
+#undef BPF_LINK_TYPE
+};
+
+/* bpf_check() is a static code analyzer that walks eBPF program
+ * instruction by instruction and updates register/stack state.
+ * All paths of conditional branches are analyzed until 'bpf_exit' insn.
+ *
+ * The first pass is depth-first-search to check that the program is a DAG.
+ * It rejects the following programs:
+ * - larger than BPF_MAXINSNS insns
+ * - if loop is present (detected via back-edge)
+ * - unreachable insns exist (shouldn't be a forest. program = one function)
+ * - out of bounds or malformed jumps
+ * The second pass is all possible path descent from the 1st insn.
+ * Since it's analyzing all paths through the program, the length of the
+ * analysis is limited to 64k insn, which may be hit even if total number of
+ * insn is less then 4K, but there are too many branches that change stack/regs.
+ * Number of 'branches to be analyzed' is limited to 1k
+ *
+ * On entry to each instruction, each register has a type, and the instruction
+ * changes the types of the registers depending on instruction semantics.
+ * If instruction is BPF_MOV64_REG(BPF_REG_1, BPF_REG_5), then type of R5 is
+ * copied to R1.
+ *
+ * All registers are 64-bit.
+ * R0 - return register
+ * R1-R5 argument passing registers
+ * R6-R9 callee saved registers
+ * R10 - frame pointer read-only
+ *
+ * At the start of BPF program the register R1 contains a pointer to bpf_context
+ * and has type PTR_TO_CTX.
+ *
+ * Verifier tracks arithmetic operations on pointers in case:
+ *    BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
+ *    BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -20),
+ * 1st insn copies R10 (which has FRAME_PTR) type into R1
+ * and 2nd arithmetic instruction is pattern matched to recognize
+ * that it wants to construct a pointer to some element within stack.
+ * So after 2nd insn, the register R1 has type PTR_TO_STACK
+ * (and -20 constant is saved for further stack bounds checking).
+ * Meaning that this reg is a pointer to stack plus known immediate constant.
+ *
+ * Most of the time the registers have SCALAR_VALUE type, which
+ * means the register has some value, but it's not a valid pointer.
+ * (like pointer plus pointer becomes SCALAR_VALUE type)
+ *
+ * When verifier sees load or store instructions the type of base register
+ * can be: PTR_TO_MAP_VALUE, PTR_TO_CTX, PTR_TO_STACK, PTR_TO_SOCKET. These are
+ * four pointer types recognized by check_mem_access() function.
+ *
+ * PTR_TO_MAP_VALUE means that this register is pointing to 'map element value'
+ * and the range of [ptr, ptr + map's value_size) is accessible.
+ *
+ * registers used to pass values to function calls are checked against
+ * function argument constraints.
+ *
+ * ARG_PTR_TO_MAP_KEY is one of such argument constraints.
+ * It means that the register type passed to this function must be
+ * PTR_TO_STACK and it will be used inside the function as
+ * 'pointer to map element key'
+ *
+ * For example the argument constraints for bpf_map_lookup_elem():
+ *   .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
+ *   .arg1_type = ARG_CONST_MAP_PTR,
+ *   .arg2_type = ARG_PTR_TO_MAP_KEY,
+ *
+ * ret_type says that this function returns 'pointer to map elem value or null'
+ * function expects 1st argument to be a const pointer to 'struct bpf_map' and
+ * 2nd argument should be a pointer to stack, which will be used inside
+ * the helper function as a pointer to map element key.
+ *
+ * On the kernel side the helper function looks like:
+ * u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
+ * {
+ *    struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
+ *    void *key = (void *) (unsigned long) r2;
+ *    void *value;
+ *
+ *    here kernel can access 'key' and 'map' pointers safely, knowing that
+ *    [key, key + map->key_size) bytes are valid and were initialized on
+ *    the stack of eBPF program.
+ * }
+ *
+ * Corresponding eBPF program may look like:
+ *    BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),  // after this insn R2 type is FRAME_PTR
+ *    BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4), // after this insn R2 type is PTR_TO_STACK
+ *    BPF_LD_MAP_FD(BPF_REG_1, map_fd),      // after this insn R1 type is CONST_PTR_TO_MAP
+ *    BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_map_lookup_elem),
+ * here verifier looks at prototype of map_lookup_elem() and sees:
+ * .arg1_type == ARG_CONST_MAP_PTR and R1->type == CONST_PTR_TO_MAP, which is ok,
+ * Now verifier knows that this map has key of R1->map_ptr->key_size bytes
+ *
+ * Then .arg2_type == ARG_PTR_TO_MAP_KEY and R2->type == PTR_TO_STACK, ok so far,
+ * Now verifier checks that [R2, R2 + map's key_size) are within stack limits
+ * and were initialized prior to this call.
+ * If it's ok, then verifier allows this BPF_CALL insn and looks at
+ * .ret_type which is RET_PTR_TO_MAP_VALUE_OR_NULL, so it sets
+ * R0->type = PTR_TO_MAP_VALUE_OR_NULL which means bpf_map_lookup_elem() function
+ * returns either pointer to map value or NULL.
+ *
+ * When type PTR_TO_MAP_VALUE_OR_NULL passes through 'if (reg != 0) goto +off'
+ * insn, the register holding that pointer in the true branch changes state to
+ * PTR_TO_MAP_VALUE and the same register changes state to CONST_IMM in the false
+ * branch. See check_cond_jmp_op().
+ *
+ * After the call R0 is set to return type of the function and registers R1-R5
+ * are set to NOT_INIT to indicate that they are no longer readable.
+ *
+ * The following reference types represent a potential reference to a kernel
+ * resource which, after first being allocated, must be checked and freed by
+ * the BPF program:
+ * - PTR_TO_SOCKET_OR_NULL, PTR_TO_SOCKET
+ *
+ * When the verifier sees a helper call return a reference type, it allocates a
+ * pointer id for the reference and stores it in the current function state.
+ * Similar to the way that PTR_TO_MAP_VALUE_OR_NULL is converted into
+ * PTR_TO_MAP_VALUE, PTR_TO_SOCKET_OR_NULL becomes PTR_TO_SOCKET when the type
+ * passes through a NULL-check conditional. For the branch wherein the state is
+ * changed to CONST_IMM, the verifier releases the reference.
+ *
+ * For each helper function that allocates a reference, such as
+ * bpf_sk_lookup_tcp(), there is a corresponding release function, such as
+ * bpf_sk_release(). When a reference type passes into the release function,
+ * the verifier also releases the reference. If any unchecked or unreleased
+ * reference remains at the end of the program, the verifier rejects it.
+ */
+
+/* verifier_state + insn_idx are pushed to stack when branch is encountered */
+struct bpf_verifier_stack_elem {
+	/* verifer state is 'st'
+	 * before processing instruction 'insn_idx'
+	 * and after processing instruction 'prev_insn_idx'
+	 */
+	struct bpf_verifier_state st;
+	int insn_idx;
+	int prev_insn_idx;
+	struct bpf_verifier_stack_elem *next;
+	/* length of verifier log at the time this state was pushed on stack */
+	u32 log_pos;
+};
+
+#define BPF_COMPLEXITY_LIMIT_JMP_SEQ	8192
+#define BPF_COMPLEXITY_LIMIT_STATES	64
+
+#define BPF_MAP_KEY_POISON	(1ULL << 63)
+#define BPF_MAP_KEY_SEEN	(1ULL << 62)
+
+#define BPF_MAP_PTR_UNPRIV	1UL
+#define BPF_MAP_PTR_POISON	((void *)((0xeB9FUL << 1) +	\
+					  POISON_POINTER_DELTA))
+#define BPF_MAP_PTR(X)		((struct bpf_map *)((X) & ~BPF_MAP_PTR_UNPRIV))
+
+static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx);
+static int release_reference(struct bpf_verifier_env *env, int ref_obj_id);
+static void invalidate_non_owning_refs(struct bpf_verifier_env *env);
+static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env);
+static int ref_set_non_owning(struct bpf_verifier_env *env,
+			      struct bpf_reg_state *reg);
+static void specialize_kfunc(struct bpf_verifier_env *env,
+			     u32 func_id, u16 offset, unsigned long *addr);
+static bool is_trusted_reg(const struct bpf_reg_state *reg);
+
+static bool bpf_map_ptr_poisoned(const struct bpf_insn_aux_data *aux)
+{
+	return BPF_MAP_PTR(aux->map_ptr_state) == BPF_MAP_PTR_POISON;
+}
+
+static bool bpf_map_ptr_unpriv(const struct bpf_insn_aux_data *aux)
+{
+	return aux->map_ptr_state & BPF_MAP_PTR_UNPRIV;
+}
+
+static void bpf_map_ptr_store(struct bpf_insn_aux_data *aux,
+			      const struct bpf_map *map, bool unpriv)
+{
+	BUILD_BUG_ON((unsigned long)BPF_MAP_PTR_POISON & BPF_MAP_PTR_UNPRIV);
+	unpriv |= bpf_map_ptr_unpriv(aux);
+	aux->map_ptr_state = (unsigned long)map |
+			     (unpriv ? BPF_MAP_PTR_UNPRIV : 0UL);
+}
+
+static bool bpf_map_key_poisoned(const struct bpf_insn_aux_data *aux)
+{
+	return aux->map_key_state & BPF_MAP_KEY_POISON;
+}
+
+static bool bpf_map_key_unseen(const struct bpf_insn_aux_data *aux)
+{
+	return !(aux->map_key_state & BPF_MAP_KEY_SEEN);
+}
+
+static u64 bpf_map_key_immediate(const struct bpf_insn_aux_data *aux)
+{
+	return aux->map_key_state & ~(BPF_MAP_KEY_SEEN | BPF_MAP_KEY_POISON);
+}
+
+static void bpf_map_key_store(struct bpf_insn_aux_data *aux, u64 state)
+{
+	bool poisoned = bpf_map_key_poisoned(aux);
+
+	aux->map_key_state = state | BPF_MAP_KEY_SEEN |
+			     (poisoned ? BPF_MAP_KEY_POISON : 0ULL);
+}
+
+static bool bpf_helper_call(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL) &&
+	       insn->src_reg == 0;
+}
+
+static bool bpf_pseudo_call(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL) &&
+	       insn->src_reg == BPF_PSEUDO_CALL;
+}
+
+static bool bpf_pseudo_kfunc_call(const struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL) &&
+	       insn->src_reg == BPF_PSEUDO_KFUNC_CALL;
+}
+
+struct bpf_call_arg_meta {
+	struct bpf_map *map_ptr;
+	bool raw_mode;
+	bool pkt_access;
+	u8 release_regno;
+	int regno;
+	int access_size;
+	int mem_size;
+	u64 msize_max_value;
+	int ref_obj_id;
+	int dynptr_id;
+	int map_uid;
+	int func_id;
+	struct btf *btf;
+	u32 btf_id;
+	struct btf *ret_btf;
+	u32 ret_btf_id;
+	u32 subprogno;
+	struct btf_field *kptr_field;
+};
+
+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;
+	u32 ret_btf_id;
+	u64 r0_size;
+	u32 subprogno;
+	struct {
+		u64 value;
+		bool found;
+	} arg_constant;
+
+	/* arg_{btf,btf_id,owning_ref} are used by kfunc-specific handling,
+	 * generally to pass info about user-defined local kptr types to later
+	 * verification logic
+	 *   bpf_obj_drop
+	 *     Record the local kptr type to be drop'd
+	 *   bpf_refcount_acquire (via KF_ARG_PTR_TO_REFCOUNTED_KPTR arg type)
+	 *     Record the local kptr type to be refcount_incr'd and use
+	 *     arg_owning_ref to determine whether refcount_acquire should be
+	 *     fallible
+	 */
+	struct btf *arg_btf;
+	u32 arg_btf_id;
+	bool arg_owning_ref;
+
+	struct {
+		struct btf_field *field;
+	} arg_list_head;
+	struct {
+		struct btf_field *field;
+	} arg_rbtree_root;
+	struct {
+		enum bpf_dynptr_type type;
+		u32 id;
+		u32 ref_obj_id;
+	} initialized_dynptr;
+	struct {
+		u8 spi;
+		u8 frameno;
+	} iter;
+	u64 mem_size;
+};
+
+struct btf *btf_vmlinux;
+
+static DEFINE_MUTEX(bpf_verifier_lock);
+
+static const struct bpf_line_info *
+find_linfo(const struct bpf_verifier_env *env, u32 insn_off)
+{
+	const struct bpf_line_info *linfo;
+	const struct bpf_prog *prog;
+	u32 i, nr_linfo;
+
+	prog = env->prog;
+	nr_linfo = prog->aux->nr_linfo;
+
+	if (!nr_linfo || insn_off >= prog->len)
+		return NULL;
+
+	linfo = prog->aux->linfo;
+	for (i = 1; i < nr_linfo; i++)
+		if (insn_off < linfo[i].insn_off)
+			break;
+
+	return &linfo[i - 1];
+}
+
+__printf(2, 3) static void verbose(void *private_data, const char *fmt, ...)
+{
+	struct bpf_verifier_env *env = private_data;
+	va_list args;
+
+	if (!bpf_verifier_log_needed(&env->log))
+		return;
+
+	va_start(args, fmt);
+	bpf_verifier_vlog(&env->log, fmt, args);
+	va_end(args);
+}
+
+static const char *ltrim(const char *s)
+{
+	while (isspace(*s))
+		s++;
+
+	return s;
+}
+
+__printf(3, 4) static void verbose_linfo(struct bpf_verifier_env *env,
+					 u32 insn_off,
+					 const char *prefix_fmt, ...)
+{
+	const struct bpf_line_info *linfo;
+
+	if (!bpf_verifier_log_needed(&env->log))
+		return;
+
+	linfo = find_linfo(env, insn_off);
+	if (!linfo || linfo == env->prev_linfo)
+		return;
+
+	if (prefix_fmt) {
+		va_list args;
+
+		va_start(args, prefix_fmt);
+		bpf_verifier_vlog(&env->log, prefix_fmt, args);
+		va_end(args);
+	}
+
+	verbose(env, "%s\n",
+		ltrim(btf_name_by_offset(env->prog->aux->btf,
+					 linfo->line_off)));
+
+	env->prev_linfo = linfo;
+}
+
+static void verbose_invalid_scalar(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *reg,
+				   struct tnum *range, const char *ctx,
+				   const char *reg_name)
+{
+	char tn_buf[48];
+
+	verbose(env, "At %s the register %s ", ctx, reg_name);
+	if (!tnum_is_unknown(reg->var_off)) {
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "has value %s", tn_buf);
+	} else {
+		verbose(env, "has unknown scalar value");
+	}
+	tnum_strn(tn_buf, sizeof(tn_buf), *range);
+	verbose(env, " should have been in %s\n", tn_buf);
+}
+
+static bool type_is_pkt_pointer(enum bpf_reg_type type)
+{
+	type = base_type(type);
+	return type == PTR_TO_PACKET ||
+	       type == PTR_TO_PACKET_META;
+}
+
+static bool type_is_sk_pointer(enum bpf_reg_type type)
+{
+	return type == PTR_TO_SOCKET ||
+		type == PTR_TO_SOCK_COMMON ||
+		type == PTR_TO_TCP_SOCK ||
+		type == PTR_TO_XDP_SOCK;
+}
+
+static bool type_may_be_null(u32 type)
+{
+	return type & PTR_MAYBE_NULL;
+}
+
+static bool reg_not_null(const struct bpf_reg_state *reg)
+{
+	enum bpf_reg_type type;
+
+	type = reg->type;
+	if (type_may_be_null(type))
+		return false;
+
+	type = base_type(type);
+	return type == PTR_TO_SOCKET ||
+		type == PTR_TO_TCP_SOCK ||
+		type == PTR_TO_MAP_VALUE ||
+		type == PTR_TO_MAP_KEY ||
+		type == PTR_TO_SOCK_COMMON ||
+		(type == PTR_TO_BTF_ID && is_trusted_reg(reg)) ||
+		type == PTR_TO_MEM;
+}
+
+static bool type_is_ptr_alloc_obj(u32 type)
+{
+	return base_type(type) == PTR_TO_BTF_ID && type_flag(type) & MEM_ALLOC;
+}
+
+static bool type_is_non_owning_ref(u32 type)
+{
+	return type_is_ptr_alloc_obj(type) && type_flag(type) & NON_OWN_REF;
+}
+
+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 (type_is_ptr_alloc_obj(reg->type)) {
+		meta = btf_find_struct_meta(reg->btf, reg->btf_id);
+		if (meta)
+			rec = meta->record;
+	}
+	return rec;
+}
+
+static bool subprog_is_global(const struct bpf_verifier_env *env, int subprog)
+{
+	struct bpf_func_info_aux *aux = env->prog->aux->func_info_aux;
+
+	return aux && aux[subprog].linkage == BTF_FUNC_GLOBAL;
+}
+
+static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
+{
+	return btf_record_has_field(reg_btf_record(reg), BPF_SPIN_LOCK);
+}
+
+static bool type_is_rdonly_mem(u32 type)
+{
+	return type & MEM_RDONLY;
+}
+
+static bool is_acquire_function(enum bpf_func_id func_id,
+				const struct bpf_map *map)
+{
+	enum bpf_map_type map_type = map ? map->map_type : BPF_MAP_TYPE_UNSPEC;
+
+	if (func_id == BPF_FUNC_sk_lookup_tcp ||
+	    func_id == BPF_FUNC_sk_lookup_udp ||
+	    func_id == BPF_FUNC_skc_lookup_tcp ||
+	    func_id == BPF_FUNC_ringbuf_reserve ||
+	    func_id == BPF_FUNC_kptr_xchg)
+		return true;
+
+	if (func_id == BPF_FUNC_map_lookup_elem &&
+	    (map_type == BPF_MAP_TYPE_SOCKMAP ||
+	     map_type == BPF_MAP_TYPE_SOCKHASH))
+		return true;
+
+	return false;
+}
+
+static bool is_ptr_cast_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_tcp_sock ||
+		func_id == BPF_FUNC_sk_fullsock ||
+		func_id == BPF_FUNC_skc_to_tcp_sock ||
+		func_id == BPF_FUNC_skc_to_tcp6_sock ||
+		func_id == BPF_FUNC_skc_to_udp6_sock ||
+		func_id == BPF_FUNC_skc_to_mptcp_sock ||
+		func_id == BPF_FUNC_skc_to_tcp_timewait_sock ||
+		func_id == BPF_FUNC_skc_to_tcp_request_sock;
+}
+
+static bool is_dynptr_ref_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_dynptr_data;
+}
+
+static bool is_sync_callback_calling_kfunc(u32 btf_id);
+
+static bool is_sync_callback_calling_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_for_each_map_elem ||
+	       func_id == BPF_FUNC_find_vma ||
+	       func_id == BPF_FUNC_loop ||
+	       func_id == BPF_FUNC_user_ringbuf_drain;
+}
+
+static bool is_async_callback_calling_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_timer_set_callback;
+}
+
+static bool is_callback_calling_function(enum bpf_func_id func_id)
+{
+	return is_sync_callback_calling_function(func_id) ||
+	       is_async_callback_calling_function(func_id);
+}
+
+static bool is_sync_callback_calling_insn(struct bpf_insn *insn)
+{
+	return (bpf_helper_call(insn) && is_sync_callback_calling_function(insn->imm)) ||
+	       (bpf_pseudo_kfunc_call(insn) && is_sync_callback_calling_kfunc(insn->imm));
+}
+
+static bool is_storage_get_function(enum bpf_func_id func_id)
+{
+	return func_id == BPF_FUNC_sk_storage_get ||
+	       func_id == BPF_FUNC_inode_storage_get ||
+	       func_id == BPF_FUNC_task_storage_get ||
+	       func_id == BPF_FUNC_cgrp_storage_get;
+}
+
+static bool helper_multiple_ref_obj_use(enum bpf_func_id func_id,
+					const struct bpf_map *map)
+{
+	int ref_obj_uses = 0;
+
+	if (is_ptr_cast_function(func_id))
+		ref_obj_uses++;
+	if (is_acquire_function(func_id, map))
+		ref_obj_uses++;
+	if (is_dynptr_ref_function(func_id))
+		ref_obj_uses++;
+
+	return ref_obj_uses > 1;
+}
+
+static bool is_cmpxchg_insn(const struct bpf_insn *insn)
+{
+	return BPF_CLASS(insn->code) == BPF_STX &&
+	       BPF_MODE(insn->code) == BPF_ATOMIC &&
+	       insn->imm == BPF_CMPXCHG;
+}
+
+/* string representation of 'enum bpf_reg_type'
+ *
+ * Note that reg_type_str() can not appear more than once in a single verbose()
+ * statement.
+ */
+static const char *reg_type_str(struct bpf_verifier_env *env,
+				enum bpf_reg_type type)
+{
+	char postfix[16] = {0}, prefix[64] = {0};
+	static const char * const str[] = {
+		[NOT_INIT]		= "?",
+		[SCALAR_VALUE]		= "scalar",
+		[PTR_TO_CTX]		= "ctx",
+		[CONST_PTR_TO_MAP]	= "map_ptr",
+		[PTR_TO_MAP_VALUE]	= "map_value",
+		[PTR_TO_STACK]		= "fp",
+		[PTR_TO_PACKET]		= "pkt",
+		[PTR_TO_PACKET_META]	= "pkt_meta",
+		[PTR_TO_PACKET_END]	= "pkt_end",
+		[PTR_TO_FLOW_KEYS]	= "flow_keys",
+		[PTR_TO_SOCKET]		= "sock",
+		[PTR_TO_SOCK_COMMON]	= "sock_common",
+		[PTR_TO_TCP_SOCK]	= "tcp_sock",
+		[PTR_TO_TP_BUFFER]	= "tp_buffer",
+		[PTR_TO_XDP_SOCK]	= "xdp_sock",
+		[PTR_TO_BTF_ID]		= "ptr_",
+		[PTR_TO_MEM]		= "mem",
+		[PTR_TO_BUF]		= "buf",
+		[PTR_TO_FUNC]		= "func",
+		[PTR_TO_MAP_KEY]	= "map_key",
+		[CONST_PTR_TO_DYNPTR]	= "dynptr_ptr",
+	};
+
+	if (type & PTR_MAYBE_NULL) {
+		if (base_type(type) == PTR_TO_BTF_ID)
+			strncpy(postfix, "or_null_", 16);
+		else
+			strncpy(postfix, "_or_null", 16);
+	}
+
+	snprintf(prefix, sizeof(prefix), "%s%s%s%s%s%s%s",
+		 type & MEM_RDONLY ? "rdonly_" : "",
+		 type & MEM_RINGBUF ? "ringbuf_" : "",
+		 type & MEM_USER ? "user_" : "",
+		 type & MEM_PERCPU ? "percpu_" : "",
+		 type & MEM_RCU ? "rcu_" : "",
+		 type & PTR_UNTRUSTED ? "untrusted_" : "",
+		 type & PTR_TRUSTED ? "trusted_" : ""
+	);
+
+	snprintf(env->tmp_str_buf, TMP_STR_BUF_LEN, "%s%s%s",
+		 prefix, str[base_type(type)], postfix);
+	return env->tmp_str_buf;
+}
+
+static char slot_type_char[] = {
+	[STACK_INVALID]	= '?',
+	[STACK_SPILL]	= 'r',
+	[STACK_MISC]	= 'm',
+	[STACK_ZERO]	= '0',
+	[STACK_DYNPTR]	= 'd',
+	[STACK_ITER]	= 'i',
+};
+
+static void print_liveness(struct bpf_verifier_env *env,
+			   enum bpf_reg_liveness live)
+{
+	if (live & (REG_LIVE_READ | REG_LIVE_WRITTEN | REG_LIVE_DONE))
+	    verbose(env, "_");
+	if (live & REG_LIVE_READ)
+		verbose(env, "r");
+	if (live & REG_LIVE_WRITTEN)
+		verbose(env, "w");
+	if (live & REG_LIVE_DONE)
+		verbose(env, "D");
+}
+
+static int __get_spi(s32 off)
+{
+	return (-off - 1) / BPF_REG_SIZE;
+}
+
+static struct bpf_func_state *func(struct bpf_verifier_env *env,
+				   const struct bpf_reg_state *reg)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+
+	return cur->frame[reg->frameno];
+}
+
+static bool is_spi_bounds_valid(struct bpf_func_state *state, int spi, int nr_slots)
+{
+       int allocated_slots = state->allocated_stack / BPF_REG_SIZE;
+
+       /* We need to check that slots between [spi - nr_slots + 1, spi] are
+	* within [0, allocated_stack).
+	*
+	* Please note that the spi grows downwards. For example, a dynptr
+	* takes the size of two stack slots; the first slot will be at
+	* spi and the second slot will be at spi - 1.
+	*/
+       return spi - nr_slots + 1 >= 0 && spi < allocated_slots;
+}
+
+static int stack_slot_obj_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+			          const char *obj_kind, int nr_slots)
+{
+	int off, spi;
+
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env, "%s has to be at a constant offset\n", obj_kind);
+		return -EINVAL;
+	}
+
+	off = reg->off + reg->var_off.value;
+	if (off % BPF_REG_SIZE) {
+		verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
+		return -EINVAL;
+	}
+
+	spi = __get_spi(off);
+	if (spi + 1 < nr_slots) {
+		verbose(env, "cannot pass in %s at an offset=%d\n", obj_kind, off);
+		return -EINVAL;
+	}
+
+	if (!is_spi_bounds_valid(func(env, reg), spi, nr_slots))
+		return -ERANGE;
+	return spi;
+}
+
+static int dynptr_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	return stack_slot_obj_get_spi(env, reg, "dynptr", BPF_DYNPTR_NR_SLOTS);
+}
+
+static int iter_get_spi(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int nr_slots)
+{
+	return stack_slot_obj_get_spi(env, reg, "iter", nr_slots);
+}
+
+static const char *btf_type_name(const struct btf *btf, u32 id)
+{
+	return btf_name_by_offset(btf, btf_type_by_id(btf, id)->name_off);
+}
+
+static const char *dynptr_type_str(enum bpf_dynptr_type type)
+{
+	switch (type) {
+	case BPF_DYNPTR_TYPE_LOCAL:
+		return "local";
+	case BPF_DYNPTR_TYPE_RINGBUF:
+		return "ringbuf";
+	case BPF_DYNPTR_TYPE_SKB:
+		return "skb";
+	case BPF_DYNPTR_TYPE_XDP:
+		return "xdp";
+	case BPF_DYNPTR_TYPE_INVALID:
+		return "<invalid>";
+	default:
+		WARN_ONCE(1, "unknown dynptr type %d\n", type);
+		return "<unknown>";
+	}
+}
+
+static const char *iter_type_str(const struct btf *btf, u32 btf_id)
+{
+	if (!btf || btf_id == 0)
+		return "<invalid>";
+
+	/* we already validated that type is valid and has conforming name */
+	return btf_type_name(btf, btf_id) + sizeof(ITER_PREFIX) - 1;
+}
+
+static const char *iter_state_str(enum bpf_iter_state state)
+{
+	switch (state) {
+	case BPF_ITER_STATE_ACTIVE:
+		return "active";
+	case BPF_ITER_STATE_DRAINED:
+		return "drained";
+	case BPF_ITER_STATE_INVALID:
+		return "<invalid>";
+	default:
+		WARN_ONCE(1, "unknown iter state %d\n", state);
+		return "<unknown>";
+	}
+}
+
+static void mark_reg_scratched(struct bpf_verifier_env *env, u32 regno)
+{
+	env->scratched_regs |= 1U << regno;
+}
+
+static void mark_stack_slot_scratched(struct bpf_verifier_env *env, u32 spi)
+{
+	env->scratched_stack_slots |= 1ULL << spi;
+}
+
+static bool reg_scratched(const struct bpf_verifier_env *env, u32 regno)
+{
+	return (env->scratched_regs >> regno) & 1;
+}
+
+static bool stack_slot_scratched(const struct bpf_verifier_env *env, u64 regno)
+{
+	return (env->scratched_stack_slots >> regno) & 1;
+}
+
+static bool verifier_state_scratched(const struct bpf_verifier_env *env)
+{
+	return env->scratched_regs || env->scratched_stack_slots;
+}
+
+static void mark_verifier_state_clean(struct bpf_verifier_env *env)
+{
+	env->scratched_regs = 0U;
+	env->scratched_stack_slots = 0ULL;
+}
+
+/* Used for printing the entire verifier state. */
+static void mark_verifier_state_scratched(struct bpf_verifier_env *env)
+{
+	env->scratched_regs = ~0U;
+	env->scratched_stack_slots = ~0ULL;
+}
+
+static enum bpf_dynptr_type arg_to_dynptr_type(enum bpf_arg_type arg_type)
+{
+	switch (arg_type & DYNPTR_TYPE_FLAG_MASK) {
+	case DYNPTR_TYPE_LOCAL:
+		return BPF_DYNPTR_TYPE_LOCAL;
+	case DYNPTR_TYPE_RINGBUF:
+		return BPF_DYNPTR_TYPE_RINGBUF;
+	case DYNPTR_TYPE_SKB:
+		return BPF_DYNPTR_TYPE_SKB;
+	case DYNPTR_TYPE_XDP:
+		return BPF_DYNPTR_TYPE_XDP;
+	default:
+		return BPF_DYNPTR_TYPE_INVALID;
+	}
+}
+
+static enum bpf_type_flag get_dynptr_type_flag(enum bpf_dynptr_type type)
+{
+	switch (type) {
+	case BPF_DYNPTR_TYPE_LOCAL:
+		return DYNPTR_TYPE_LOCAL;
+	case BPF_DYNPTR_TYPE_RINGBUF:
+		return DYNPTR_TYPE_RINGBUF;
+	case BPF_DYNPTR_TYPE_SKB:
+		return DYNPTR_TYPE_SKB;
+	case BPF_DYNPTR_TYPE_XDP:
+		return DYNPTR_TYPE_XDP;
+	default:
+		return 0;
+	}
+}
+
+static bool dynptr_type_refcounted(enum bpf_dynptr_type type)
+{
+	return type == BPF_DYNPTR_TYPE_RINGBUF;
+}
+
+static void __mark_dynptr_reg(struct bpf_reg_state *reg,
+			      enum bpf_dynptr_type type,
+			      bool first_slot, int dynptr_id);
+
+static void __mark_reg_not_init(const struct bpf_verifier_env *env,
+				struct bpf_reg_state *reg);
+
+static void mark_dynptr_stack_regs(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *sreg1,
+				   struct bpf_reg_state *sreg2,
+				   enum bpf_dynptr_type type)
+{
+	int id = ++env->id_gen;
+
+	__mark_dynptr_reg(sreg1, type, true, id);
+	__mark_dynptr_reg(sreg2, type, false, id);
+}
+
+static void mark_dynptr_cb_reg(struct bpf_verifier_env *env,
+			       struct bpf_reg_state *reg,
+			       enum bpf_dynptr_type type)
+{
+	__mark_dynptr_reg(reg, type, true, ++env->id_gen);
+}
+
+static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
+				        struct bpf_func_state *state, int spi);
+
+static int mark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+				   enum bpf_arg_type arg_type, int insn_idx, int clone_ref_obj_id)
+{
+	struct bpf_func_state *state = func(env, reg);
+	enum bpf_dynptr_type type;
+	int spi, i, err;
+
+	spi = dynptr_get_spi(env, reg);
+	if (spi < 0)
+		return spi;
+
+	/* We cannot assume both spi and spi - 1 belong to the same dynptr,
+	 * hence we need to call destroy_if_dynptr_stack_slot twice for both,
+	 * to ensure that for the following example:
+	 *	[d1][d1][d2][d2]
+	 * spi    3   2   1   0
+	 * So marking spi = 2 should lead to destruction of both d1 and d2. In
+	 * case they do belong to same dynptr, second call won't see slot_type
+	 * as STACK_DYNPTR and will simply skip destruction.
+	 */
+	err = destroy_if_dynptr_stack_slot(env, state, spi);
+	if (err)
+		return err;
+	err = destroy_if_dynptr_stack_slot(env, state, spi - 1);
+	if (err)
+		return err;
+
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		state->stack[spi].slot_type[i] = STACK_DYNPTR;
+		state->stack[spi - 1].slot_type[i] = STACK_DYNPTR;
+	}
+
+	type = arg_to_dynptr_type(arg_type);
+	if (type == BPF_DYNPTR_TYPE_INVALID)
+		return -EINVAL;
+
+	mark_dynptr_stack_regs(env, &state->stack[spi].spilled_ptr,
+			       &state->stack[spi - 1].spilled_ptr, type);
+
+	if (dynptr_type_refcounted(type)) {
+		/* The id is used to track proper releasing */
+		int id;
+
+		if (clone_ref_obj_id)
+			id = clone_ref_obj_id;
+		else
+			id = acquire_reference_state(env, insn_idx);
+
+		if (id < 0)
+			return id;
+
+		state->stack[spi].spilled_ptr.ref_obj_id = id;
+		state->stack[spi - 1].spilled_ptr.ref_obj_id = id;
+	}
+
+	state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+	state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+	return 0;
+}
+
+static void invalidate_dynptr(struct bpf_verifier_env *env, struct bpf_func_state *state, int spi)
+{
+	int i;
+
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		state->stack[spi].slot_type[i] = STACK_INVALID;
+		state->stack[spi - 1].slot_type[i] = STACK_INVALID;
+	}
+
+	__mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
+	__mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
+
+	/* Why do we need to set REG_LIVE_WRITTEN for STACK_INVALID slot?
+	 *
+	 * While we don't allow reading STACK_INVALID, it is still possible to
+	 * do <8 byte writes marking some but not all slots as STACK_MISC. Then,
+	 * helpers or insns can do partial read of that part without failing,
+	 * but check_stack_range_initialized, check_stack_read_var_off, and
+	 * check_stack_read_fixed_off will do mark_reg_read for all 8-bytes of
+	 * the slot conservatively. Hence we need to prevent those liveness
+	 * marking walks.
+	 *
+	 * This was not a problem before because STACK_INVALID is only set by
+	 * default (where the default reg state has its reg->parent as NULL), or
+	 * in clean_live_states after REG_LIVE_DONE (at which point
+	 * mark_reg_read won't walk reg->parent chain), but not randomly during
+	 * verifier state exploration (like we did above). Hence, for our case
+	 * parentage chain will still be live (i.e. reg->parent may be
+	 * non-NULL), while earlier reg->parent was NULL, so we need
+	 * REG_LIVE_WRITTEN to screen off read marker propagation when it is
+	 * done later on reads or by mark_dynptr_read as well to unnecessary
+	 * mark registers in verifier state.
+	 */
+	state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+	state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
+}
+
+static int unmark_stack_slots_dynptr(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi, ref_obj_id, i;
+
+	spi = dynptr_get_spi(env, reg);
+	if (spi < 0)
+		return spi;
+
+	if (!dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
+		invalidate_dynptr(env, state, spi);
+		return 0;
+	}
+
+	ref_obj_id = state->stack[spi].spilled_ptr.ref_obj_id;
+
+	/* If the dynptr has a ref_obj_id, then we need to invalidate
+	 * two things:
+	 *
+	 * 1) Any dynptrs with a matching ref_obj_id (clones)
+	 * 2) Any slices derived from this dynptr.
+	 */
+
+	/* Invalidate any slices associated with this dynptr */
+	WARN_ON_ONCE(release_reference(env, ref_obj_id));
+
+	/* Invalidate any dynptr clones */
+	for (i = 1; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+		if (state->stack[i].spilled_ptr.ref_obj_id != ref_obj_id)
+			continue;
+
+		/* it should always be the case that if the ref obj id
+		 * matches then the stack slot also belongs to a
+		 * dynptr
+		 */
+		if (state->stack[i].slot_type[0] != STACK_DYNPTR) {
+			verbose(env, "verifier internal error: misconfigured ref_obj_id\n");
+			return -EFAULT;
+		}
+		if (state->stack[i].spilled_ptr.dynptr.first_slot)
+			invalidate_dynptr(env, state, i);
+	}
+
+	return 0;
+}
+
+static void __mark_reg_unknown(const struct bpf_verifier_env *env,
+			       struct bpf_reg_state *reg);
+
+static void mark_reg_invalid(const struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	if (!env->allow_ptr_leaks)
+		__mark_reg_not_init(env, reg);
+	else
+		__mark_reg_unknown(env, reg);
+}
+
+static int destroy_if_dynptr_stack_slot(struct bpf_verifier_env *env,
+				        struct bpf_func_state *state, int spi)
+{
+	struct bpf_func_state *fstate;
+	struct bpf_reg_state *dreg;
+	int i, dynptr_id;
+
+	/* We always ensure that STACK_DYNPTR is never set partially,
+	 * hence just checking for slot_type[0] is enough. This is
+	 * different for STACK_SPILL, where it may be only set for
+	 * 1 byte, so code has to use is_spilled_reg.
+	 */
+	if (state->stack[spi].slot_type[0] != STACK_DYNPTR)
+		return 0;
+
+	/* Reposition spi to first slot */
+	if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
+		spi = spi + 1;
+
+	if (dynptr_type_refcounted(state->stack[spi].spilled_ptr.dynptr.type)) {
+		verbose(env, "cannot overwrite referenced dynptr\n");
+		return -EINVAL;
+	}
+
+	mark_stack_slot_scratched(env, spi);
+	mark_stack_slot_scratched(env, spi - 1);
+
+	/* Writing partially to one dynptr stack slot destroys both. */
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		state->stack[spi].slot_type[i] = STACK_INVALID;
+		state->stack[spi - 1].slot_type[i] = STACK_INVALID;
+	}
+
+	dynptr_id = state->stack[spi].spilled_ptr.id;
+	/* Invalidate any slices associated with this dynptr */
+	bpf_for_each_reg_in_vstate(env->cur_state, fstate, dreg, ({
+		/* Dynptr slices are only PTR_TO_MEM_OR_NULL and PTR_TO_MEM */
+		if (dreg->type != (PTR_TO_MEM | PTR_MAYBE_NULL) && dreg->type != PTR_TO_MEM)
+			continue;
+		if (dreg->dynptr_id == dynptr_id)
+			mark_reg_invalid(env, dreg);
+	}));
+
+	/* Do not release reference state, we are destroying dynptr on stack,
+	 * not using some helper to release it. Just reset register.
+	 */
+	__mark_reg_not_init(env, &state->stack[spi].spilled_ptr);
+	__mark_reg_not_init(env, &state->stack[spi - 1].spilled_ptr);
+
+	/* Same reason as unmark_stack_slots_dynptr above */
+	state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+	state->stack[spi - 1].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+	return 0;
+}
+
+static bool is_dynptr_reg_valid_uninit(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	int spi;
+
+	if (reg->type == CONST_PTR_TO_DYNPTR)
+		return false;
+
+	spi = dynptr_get_spi(env, reg);
+
+	/* -ERANGE (i.e. spi not falling into allocated stack slots) isn't an
+	 * error because this just means the stack state hasn't been updated yet.
+	 * We will do check_mem_access to check and update stack bounds later.
+	 */
+	if (spi < 0 && spi != -ERANGE)
+		return false;
+
+	/* We don't need to check if the stack slots are marked by previous
+	 * dynptr initializations because we allow overwriting existing unreferenced
+	 * STACK_DYNPTR slots, see mark_stack_slots_dynptr which calls
+	 * destroy_if_dynptr_stack_slot to ensure dynptr objects at the slots we are
+	 * touching are completely destructed before we reinitialize them for a new
+	 * one. For referenced ones, destroy_if_dynptr_stack_slot returns an error early
+	 * instead of delaying it until the end where the user will get "Unreleased
+	 * reference" error.
+	 */
+	return true;
+}
+
+static bool is_dynptr_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int i, spi;
+
+	/* This already represents first slot of initialized bpf_dynptr.
+	 *
+	 * CONST_PTR_TO_DYNPTR already has fixed and var_off as 0 due to
+	 * check_func_arg_reg_off's logic, so we don't need to check its
+	 * offset and alignment.
+	 */
+	if (reg->type == CONST_PTR_TO_DYNPTR)
+		return true;
+
+	spi = dynptr_get_spi(env, reg);
+	if (spi < 0)
+		return false;
+	if (!state->stack[spi].spilled_ptr.dynptr.first_slot)
+		return false;
+
+	for (i = 0; i < BPF_REG_SIZE; i++) {
+		if (state->stack[spi].slot_type[i] != STACK_DYNPTR ||
+		    state->stack[spi - 1].slot_type[i] != STACK_DYNPTR)
+			return false;
+	}
+
+	return true;
+}
+
+static bool is_dynptr_type_expected(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+				    enum bpf_arg_type arg_type)
+{
+	struct bpf_func_state *state = func(env, reg);
+	enum bpf_dynptr_type dynptr_type;
+	int spi;
+
+	/* ARG_PTR_TO_DYNPTR takes any type of dynptr */
+	if (arg_type == ARG_PTR_TO_DYNPTR)
+		return true;
+
+	dynptr_type = arg_to_dynptr_type(arg_type);
+	if (reg->type == CONST_PTR_TO_DYNPTR) {
+		return reg->dynptr.type == dynptr_type;
+	} else {
+		spi = dynptr_get_spi(env, reg);
+		if (spi < 0)
+			return false;
+		return state->stack[spi].spilled_ptr.dynptr.type == dynptr_type;
+	}
+}
+
+static void __mark_reg_known_zero(struct bpf_reg_state *reg);
+
+static int mark_stack_slots_iter(struct bpf_verifier_env *env,
+				 struct bpf_reg_state *reg, int insn_idx,
+				 struct btf *btf, u32 btf_id, int nr_slots)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi, i, j, id;
+
+	spi = iter_get_spi(env, reg, nr_slots);
+	if (spi < 0)
+		return spi;
+
+	id = acquire_reference_state(env, insn_idx);
+	if (id < 0)
+		return id;
+
+	for (i = 0; i < nr_slots; i++) {
+		struct bpf_stack_state *slot = &state->stack[spi - i];
+		struct bpf_reg_state *st = &slot->spilled_ptr;
+
+		__mark_reg_known_zero(st);
+		st->type = PTR_TO_STACK; /* we don't have dedicated reg type */
+		st->live |= REG_LIVE_WRITTEN;
+		st->ref_obj_id = i == 0 ? id : 0;
+		st->iter.btf = btf;
+		st->iter.btf_id = btf_id;
+		st->iter.state = BPF_ITER_STATE_ACTIVE;
+		st->iter.depth = 0;
+
+		for (j = 0; j < BPF_REG_SIZE; j++)
+			slot->slot_type[j] = STACK_ITER;
+
+		mark_stack_slot_scratched(env, spi - i);
+	}
+
+	return 0;
+}
+
+static int unmark_stack_slots_iter(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *reg, int nr_slots)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi, i, j;
+
+	spi = iter_get_spi(env, reg, nr_slots);
+	if (spi < 0)
+		return spi;
+
+	for (i = 0; i < nr_slots; i++) {
+		struct bpf_stack_state *slot = &state->stack[spi - i];
+		struct bpf_reg_state *st = &slot->spilled_ptr;
+
+		if (i == 0)
+			WARN_ON_ONCE(release_reference(env, st->ref_obj_id));
+
+		__mark_reg_not_init(env, st);
+
+		/* see unmark_stack_slots_dynptr() for why we need to set REG_LIVE_WRITTEN */
+		st->live |= REG_LIVE_WRITTEN;
+
+		for (j = 0; j < BPF_REG_SIZE; j++)
+			slot->slot_type[j] = STACK_INVALID;
+
+		mark_stack_slot_scratched(env, spi - i);
+	}
+
+	return 0;
+}
+
+static bool is_iter_reg_valid_uninit(struct bpf_verifier_env *env,
+				     struct bpf_reg_state *reg, int nr_slots)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi, i, j;
+
+	/* For -ERANGE (i.e. spi not falling into allocated stack slots), we
+	 * will do check_mem_access to check and update stack bounds later, so
+	 * return true for that case.
+	 */
+	spi = iter_get_spi(env, reg, nr_slots);
+	if (spi == -ERANGE)
+		return true;
+	if (spi < 0)
+		return false;
+
+	for (i = 0; i < nr_slots; i++) {
+		struct bpf_stack_state *slot = &state->stack[spi - i];
+
+		for (j = 0; j < BPF_REG_SIZE; j++)
+			if (slot->slot_type[j] == STACK_ITER)
+				return false;
+	}
+
+	return true;
+}
+
+static bool is_iter_reg_valid_init(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+				   struct btf *btf, u32 btf_id, int nr_slots)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi, i, j;
+
+	spi = iter_get_spi(env, reg, nr_slots);
+	if (spi < 0)
+		return false;
+
+	for (i = 0; i < nr_slots; i++) {
+		struct bpf_stack_state *slot = &state->stack[spi - i];
+		struct bpf_reg_state *st = &slot->spilled_ptr;
+
+		/* only main (first) slot has ref_obj_id set */
+		if (i == 0 && !st->ref_obj_id)
+			return false;
+		if (i != 0 && st->ref_obj_id)
+			return false;
+		if (st->iter.btf != btf || st->iter.btf_id != btf_id)
+			return false;
+
+		for (j = 0; j < BPF_REG_SIZE; j++)
+			if (slot->slot_type[j] != STACK_ITER)
+				return false;
+	}
+
+	return true;
+}
+
+/* Check if given stack slot is "special":
+ *   - spilled register state (STACK_SPILL);
+ *   - dynptr state (STACK_DYNPTR);
+ *   - iter state (STACK_ITER).
+ */
+static bool is_stack_slot_special(const struct bpf_stack_state *stack)
+{
+	enum bpf_stack_slot_type type = stack->slot_type[BPF_REG_SIZE - 1];
+
+	switch (type) {
+	case STACK_SPILL:
+	case STACK_DYNPTR:
+	case STACK_ITER:
+		return true;
+	case STACK_INVALID:
+	case STACK_MISC:
+	case STACK_ZERO:
+		return false;
+	default:
+		WARN_ONCE(1, "unknown stack slot type %d\n", type);
+		return true;
+	}
+}
+
+/* The reg state of a pointer or a bounded scalar was saved when
+ * it was spilled to the stack.
+ */
+static bool is_spilled_reg(const struct bpf_stack_state *stack)
+{
+	return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL;
+}
+
+static bool is_spilled_scalar_reg(const struct bpf_stack_state *stack)
+{
+	return stack->slot_type[BPF_REG_SIZE - 1] == STACK_SPILL &&
+	       stack->spilled_ptr.type == SCALAR_VALUE;
+}
+
+static void scrub_spilled_slot(u8 *stype)
+{
+	if (*stype != STACK_INVALID)
+		*stype = STACK_MISC;
+}
+
+static void print_verifier_state(struct bpf_verifier_env *env,
+				 const struct bpf_func_state *state,
+				 bool print_all)
+{
+	const struct bpf_reg_state *reg;
+	enum bpf_reg_type t;
+	int i;
+
+	if (state->frameno)
+		verbose(env, " frame%d:", state->frameno);
+	for (i = 0; i < MAX_BPF_REG; i++) {
+		reg = &state->regs[i];
+		t = reg->type;
+		if (t == NOT_INIT)
+			continue;
+		if (!print_all && !reg_scratched(env, i))
+			continue;
+		verbose(env, " R%d", i);
+		print_liveness(env, reg->live);
+		verbose(env, "=");
+		if (t == SCALAR_VALUE && reg->precise)
+			verbose(env, "P");
+		if ((t == SCALAR_VALUE || t == PTR_TO_STACK) &&
+		    tnum_is_const(reg->var_off)) {
+			/* reg->off should be 0 for SCALAR_VALUE */
+			verbose(env, "%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
+			verbose(env, "%lld", reg->var_off.value + reg->off);
+		} else {
+			const char *sep = "";
+
+			verbose(env, "%s", reg_type_str(env, t));
+			if (base_type(t) == PTR_TO_BTF_ID)
+				verbose(env, "%s", btf_type_name(reg->btf, reg->btf_id));
+			verbose(env, "(");
+/*
+ * _a stands for append, was shortened to avoid multiline statements below.
+ * This macro is used to output a comma separated list of attributes.
+ */
+#define verbose_a(fmt, ...) ({ verbose(env, "%s" fmt, sep, __VA_ARGS__); sep = ","; })
+
+			if (reg->id)
+				verbose_a("id=%d", reg->id);
+			if (reg->ref_obj_id)
+				verbose_a("ref_obj_id=%d", reg->ref_obj_id);
+			if (type_is_non_owning_ref(reg->type))
+				verbose_a("%s", "non_own_ref");
+			if (t != SCALAR_VALUE)
+				verbose_a("off=%d", reg->off);
+			if (type_is_pkt_pointer(t))
+				verbose_a("r=%d", reg->range);
+			else if (base_type(t) == CONST_PTR_TO_MAP ||
+				 base_type(t) == PTR_TO_MAP_KEY ||
+				 base_type(t) == PTR_TO_MAP_VALUE)
+				verbose_a("ks=%d,vs=%d",
+					  reg->map_ptr->key_size,
+					  reg->map_ptr->value_size);
+			if (tnum_is_const(reg->var_off)) {
+				/* Typically an immediate SCALAR_VALUE, but
+				 * could be a pointer whose offset is too big
+				 * for reg->off
+				 */
+				verbose_a("imm=%llx", reg->var_off.value);
+			} else {
+				if (reg->smin_value != reg->umin_value &&
+				    reg->smin_value != S64_MIN)
+					verbose_a("smin=%lld", (long long)reg->smin_value);
+				if (reg->smax_value != reg->umax_value &&
+				    reg->smax_value != S64_MAX)
+					verbose_a("smax=%lld", (long long)reg->smax_value);
+				if (reg->umin_value != 0)
+					verbose_a("umin=%llu", (unsigned long long)reg->umin_value);
+				if (reg->umax_value != U64_MAX)
+					verbose_a("umax=%llu", (unsigned long long)reg->umax_value);
+				if (!tnum_is_unknown(reg->var_off)) {
+					char tn_buf[48];
+
+					tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+					verbose_a("var_off=%s", tn_buf);
+				}
+				if (reg->s32_min_value != reg->smin_value &&
+				    reg->s32_min_value != S32_MIN)
+					verbose_a("s32_min=%d", (int)(reg->s32_min_value));
+				if (reg->s32_max_value != reg->smax_value &&
+				    reg->s32_max_value != S32_MAX)
+					verbose_a("s32_max=%d", (int)(reg->s32_max_value));
+				if (reg->u32_min_value != reg->umin_value &&
+				    reg->u32_min_value != U32_MIN)
+					verbose_a("u32_min=%d", (int)(reg->u32_min_value));
+				if (reg->u32_max_value != reg->umax_value &&
+				    reg->u32_max_value != U32_MAX)
+					verbose_a("u32_max=%d", (int)(reg->u32_max_value));
+			}
+#undef verbose_a
+
+			verbose(env, ")");
+		}
+	}
+	for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+		char types_buf[BPF_REG_SIZE + 1];
+		bool valid = false;
+		int j;
+
+		for (j = 0; j < BPF_REG_SIZE; j++) {
+			if (state->stack[i].slot_type[j] != STACK_INVALID)
+				valid = true;
+			types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
+		}
+		types_buf[BPF_REG_SIZE] = 0;
+		if (!valid)
+			continue;
+		if (!print_all && !stack_slot_scratched(env, i))
+			continue;
+		switch (state->stack[i].slot_type[BPF_REG_SIZE - 1]) {
+		case STACK_SPILL:
+			reg = &state->stack[i].spilled_ptr;
+			t = reg->type;
+
+			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+			print_liveness(env, reg->live);
+			verbose(env, "=%s", t == SCALAR_VALUE ? "" : reg_type_str(env, t));
+			if (t == SCALAR_VALUE && reg->precise)
+				verbose(env, "P");
+			if (t == SCALAR_VALUE && tnum_is_const(reg->var_off))
+				verbose(env, "%lld", reg->var_off.value + reg->off);
+			break;
+		case STACK_DYNPTR:
+			i += BPF_DYNPTR_NR_SLOTS - 1;
+			reg = &state->stack[i].spilled_ptr;
+
+			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+			print_liveness(env, reg->live);
+			verbose(env, "=dynptr_%s", dynptr_type_str(reg->dynptr.type));
+			if (reg->ref_obj_id)
+				verbose(env, "(ref_id=%d)", reg->ref_obj_id);
+			break;
+		case STACK_ITER:
+			/* only main slot has ref_obj_id set; skip others */
+			reg = &state->stack[i].spilled_ptr;
+			if (!reg->ref_obj_id)
+				continue;
+
+			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+			print_liveness(env, reg->live);
+			verbose(env, "=iter_%s(ref_id=%d,state=%s,depth=%u)",
+				iter_type_str(reg->iter.btf, reg->iter.btf_id),
+				reg->ref_obj_id, iter_state_str(reg->iter.state),
+				reg->iter.depth);
+			break;
+		case STACK_MISC:
+		case STACK_ZERO:
+		default:
+			reg = &state->stack[i].spilled_ptr;
+
+			for (j = 0; j < BPF_REG_SIZE; j++)
+				types_buf[j] = slot_type_char[state->stack[i].slot_type[j]];
+			types_buf[BPF_REG_SIZE] = 0;
+
+			verbose(env, " fp%d", (-i - 1) * BPF_REG_SIZE);
+			print_liveness(env, reg->live);
+			verbose(env, "=%s", types_buf);
+			break;
+		}
+	}
+	if (state->acquired_refs && state->refs[0].id) {
+		verbose(env, " refs=%d", state->refs[0].id);
+		for (i = 1; i < state->acquired_refs; i++)
+			if (state->refs[i].id)
+				verbose(env, ",%d", state->refs[i].id);
+	}
+	if (state->in_callback_fn)
+		verbose(env, " cb");
+	if (state->in_async_callback_fn)
+		verbose(env, " async_cb");
+	verbose(env, "\n");
+	if (!print_all)
+		mark_verifier_state_clean(env);
+}
+
+static inline u32 vlog_alignment(u32 pos)
+{
+	return round_up(max(pos + BPF_LOG_MIN_ALIGNMENT / 2, BPF_LOG_ALIGNMENT),
+			BPF_LOG_MIN_ALIGNMENT) - pos - 1;
+}
+
+static void print_insn_state(struct bpf_verifier_env *env,
+			     const struct bpf_func_state *state)
+{
+	if (env->prev_log_pos && env->prev_log_pos == env->log.end_pos) {
+		/* remove new line character */
+		bpf_vlog_reset(&env->log, env->prev_log_pos - 1);
+		verbose(env, "%*c;", vlog_alignment(env->prev_insn_print_pos), ' ');
+	} else {
+		verbose(env, "%d:", env->insn_idx);
+	}
+	print_verifier_state(env, state, false);
+}
+
+/* copy array src of length n * size bytes to dst. dst is reallocated if it's too
+ * small to hold src. This is different from krealloc since we don't want to preserve
+ * the contents of dst.
+ *
+ * Leaves dst untouched if src is NULL or length is zero. Returns NULL if memory could
+ * not be allocated.
+ */
+static void *copy_array(void *dst, const void *src, size_t n, size_t size, gfp_t flags)
+{
+	size_t alloc_bytes;
+	void *orig = dst;
+	size_t bytes;
+
+	if (ZERO_OR_NULL_PTR(src))
+		goto out;
+
+	if (unlikely(check_mul_overflow(n, size, &bytes)))
+		return NULL;
+
+	alloc_bytes = max(ksize(orig), kmalloc_size_roundup(bytes));
+	dst = krealloc(orig, alloc_bytes, flags);
+	if (!dst) {
+		kfree(orig);
+		return NULL;
+	}
+
+	memcpy(dst, src, bytes);
+out:
+	return dst ? dst : ZERO_SIZE_PTR;
+}
+
+/* resize an array from old_n items to new_n items. the array is reallocated if it's too
+ * small to hold new_n items. new items are zeroed out if the array grows.
+ *
+ * Contrary to krealloc_array, does not free arr if new_n is zero.
+ */
+static void *realloc_array(void *arr, size_t old_n, size_t new_n, size_t size)
+{
+	size_t alloc_size;
+	void *new_arr;
+
+	if (!new_n || old_n == new_n)
+		goto out;
+
+	alloc_size = kmalloc_size_roundup(size_mul(new_n, size));
+	new_arr = krealloc(arr, alloc_size, GFP_KERNEL);
+	if (!new_arr) {
+		kfree(arr);
+		return NULL;
+	}
+	arr = new_arr;
+
+	if (new_n > old_n)
+		memset(arr + old_n * size, 0, (new_n - old_n) * size);
+
+out:
+	return arr ? arr : ZERO_SIZE_PTR;
+}
+
+static int copy_reference_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
+{
+	dst->refs = copy_array(dst->refs, src->refs, src->acquired_refs,
+			       sizeof(struct bpf_reference_state), GFP_KERNEL);
+	if (!dst->refs)
+		return -ENOMEM;
+
+	dst->acquired_refs = src->acquired_refs;
+	return 0;
+}
+
+static int copy_stack_state(struct bpf_func_state *dst, const struct bpf_func_state *src)
+{
+	size_t n = src->allocated_stack / BPF_REG_SIZE;
+
+	dst->stack = copy_array(dst->stack, src->stack, n, sizeof(struct bpf_stack_state),
+				GFP_KERNEL);
+	if (!dst->stack)
+		return -ENOMEM;
+
+	dst->allocated_stack = src->allocated_stack;
+	return 0;
+}
+
+static int resize_reference_state(struct bpf_func_state *state, size_t n)
+{
+	state->refs = realloc_array(state->refs, state->acquired_refs, n,
+				    sizeof(struct bpf_reference_state));
+	if (!state->refs)
+		return -ENOMEM;
+
+	state->acquired_refs = n;
+	return 0;
+}
+
+/* Possibly update state->allocated_stack to be at least size bytes. Also
+ * possibly update the function's high-water mark in its bpf_subprog_info.
+ */
+static int grow_stack_state(struct bpf_verifier_env *env, struct bpf_func_state *state, int size)
+{
+	size_t old_n = state->allocated_stack / BPF_REG_SIZE, n = size / BPF_REG_SIZE;
+
+	if (old_n >= n)
+		return 0;
+
+	state->stack = realloc_array(state->stack, old_n, n, sizeof(struct bpf_stack_state));
+	if (!state->stack)
+		return -ENOMEM;
+
+	state->allocated_stack = size;
+
+	/* update known max for given subprogram */
+	if (env->subprog_info[state->subprogno].stack_depth < size)
+		env->subprog_info[state->subprogno].stack_depth = size;
+
+	return 0;
+}
+
+/* Acquire a pointer id from the env and update the state->refs to include
+ * this new pointer reference.
+ * On success, returns a valid pointer id to associate with the register
+ * On failure, returns a negative errno.
+ */
+static int acquire_reference_state(struct bpf_verifier_env *env, int insn_idx)
+{
+	struct bpf_func_state *state = cur_func(env);
+	int new_ofs = state->acquired_refs;
+	int id, err;
+
+	err = resize_reference_state(state, state->acquired_refs + 1);
+	if (err)
+		return err;
+	id = ++env->id_gen;
+	state->refs[new_ofs].id = id;
+	state->refs[new_ofs].insn_idx = insn_idx;
+	state->refs[new_ofs].callback_ref = state->in_callback_fn ? state->frameno : 0;
+
+	return id;
+}
+
+/* release function corresponding to acquire_reference_state(). Idempotent. */
+static int release_reference_state(struct bpf_func_state *state, int ptr_id)
+{
+	int i, last_idx;
+
+	last_idx = state->acquired_refs - 1;
+	for (i = 0; i < state->acquired_refs; i++) {
+		if (state->refs[i].id == ptr_id) {
+			/* Cannot release caller references in callbacks */
+			if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
+				return -EINVAL;
+			if (last_idx && i != last_idx)
+				memcpy(&state->refs[i], &state->refs[last_idx],
+				       sizeof(*state->refs));
+			memset(&state->refs[last_idx], 0, sizeof(*state->refs));
+			state->acquired_refs--;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static void free_func_state(struct bpf_func_state *state)
+{
+	if (!state)
+		return;
+	kfree(state->refs);
+	kfree(state->stack);
+	kfree(state);
+}
+
+static void clear_jmp_history(struct bpf_verifier_state *state)
+{
+	kfree(state->jmp_history);
+	state->jmp_history = NULL;
+	state->jmp_history_cnt = 0;
+}
+
+static void free_verifier_state(struct bpf_verifier_state *state,
+				bool free_self)
+{
+	int i;
+
+	for (i = 0; i <= state->curframe; i++) {
+		free_func_state(state->frame[i]);
+		state->frame[i] = NULL;
+	}
+	clear_jmp_history(state);
+	if (free_self)
+		kfree(state);
+}
+
+/* copy verifier state from src to dst growing dst stack space
+ * when necessary to accommodate larger src stack
+ */
+static int copy_func_state(struct bpf_func_state *dst,
+			   const struct bpf_func_state *src)
+{
+	int err;
+
+	memcpy(dst, src, offsetof(struct bpf_func_state, acquired_refs));
+	err = copy_reference_state(dst, src);
+	if (err)
+		return err;
+	return copy_stack_state(dst, src);
+}
+
+static int copy_verifier_state(struct bpf_verifier_state *dst_state,
+			       const struct bpf_verifier_state *src)
+{
+	struct bpf_func_state *dst;
+	int i, err;
+
+	dst_state->jmp_history = copy_array(dst_state->jmp_history, src->jmp_history,
+					    src->jmp_history_cnt, sizeof(struct bpf_idx_pair),
+					    GFP_USER);
+	if (!dst_state->jmp_history)
+		return -ENOMEM;
+	dst_state->jmp_history_cnt = src->jmp_history_cnt;
+
+	/* if dst has more stack frames then src frame, free them */
+	for (i = src->curframe + 1; i <= dst_state->curframe; i++) {
+		free_func_state(dst_state->frame[i]);
+		dst_state->frame[i] = NULL;
+	}
+	dst_state->speculative = src->speculative;
+	dst_state->active_rcu_lock = src->active_rcu_lock;
+	dst_state->curframe = src->curframe;
+	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;
+	dst_state->last_insn_idx = src->last_insn_idx;
+	dst_state->dfs_depth = src->dfs_depth;
+	dst_state->callback_unroll_depth = src->callback_unroll_depth;
+	dst_state->used_as_loop_entry = src->used_as_loop_entry;
+	for (i = 0; i <= src->curframe; i++) {
+		dst = dst_state->frame[i];
+		if (!dst) {
+			dst = kzalloc(sizeof(*dst), GFP_KERNEL);
+			if (!dst)
+				return -ENOMEM;
+			dst_state->frame[i] = dst;
+		}
+		err = copy_func_state(dst, src->frame[i]);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static u32 state_htab_size(struct bpf_verifier_env *env)
+{
+	return env->prog->len;
+}
+
+static struct bpf_verifier_state_list **explored_state(struct bpf_verifier_env *env, int idx)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+	struct bpf_func_state *state = cur->frame[cur->curframe];
+
+	return &env->explored_states[(idx ^ state->callsite) % state_htab_size(env)];
+}
+
+static bool same_callsites(struct bpf_verifier_state *a, struct bpf_verifier_state *b)
+{
+	int fr;
+
+	if (a->curframe != b->curframe)
+		return false;
+
+	for (fr = a->curframe; fr >= 0; fr--)
+		if (a->frame[fr]->callsite != b->frame[fr]->callsite)
+			return false;
+
+	return true;
+}
+
+/* Open coded iterators allow back-edges in the state graph in order to
+ * check unbounded loops that iterators.
+ *
+ * In is_state_visited() it is necessary to know if explored states are
+ * part of some loops in order to decide whether non-exact states
+ * comparison could be used:
+ * - non-exact states comparison establishes sub-state relation and uses
+ *   read and precision marks to do so, these marks are propagated from
+ *   children states and thus are not guaranteed to be final in a loop;
+ * - exact states comparison just checks if current and explored states
+ *   are identical (and thus form a back-edge).
+ *
+ * Paper "A New Algorithm for Identifying Loops in Decompilation"
+ * by Tao Wei, Jian Mao, Wei Zou and Yu Chen [1] presents a convenient
+ * algorithm for loop structure detection and gives an overview of
+ * relevant terminology. It also has helpful illustrations.
+ *
+ * [1] https://api.semanticscholar.org/CorpusID:15784067
+ *
+ * We use a similar algorithm but because loop nested structure is
+ * irrelevant for verifier ours is significantly simpler and resembles
+ * strongly connected components algorithm from Sedgewick's textbook.
+ *
+ * Define topmost loop entry as a first node of the loop traversed in a
+ * depth first search starting from initial state. The goal of the loop
+ * tracking algorithm is to associate topmost loop entries with states
+ * derived from these entries.
+ *
+ * For each step in the DFS states traversal algorithm needs to identify
+ * the following situations:
+ *
+ *          initial                     initial                   initial
+ *            |                           |                         |
+ *            V                           V                         V
+ *           ...                         ...           .---------> hdr
+ *            |                           |            |            |
+ *            V                           V            |            V
+ *           cur                     .-> succ          |    .------...
+ *            |                      |    |            |    |       |
+ *            V                      |    V            |    V       V
+ *           succ                    '-- cur           |   ...     ...
+ *                                                     |    |       |
+ *                                                     |    V       V
+ *                                                     |   succ <- cur
+ *                                                     |    |
+ *                                                     |    V
+ *                                                     |   ...
+ *                                                     |    |
+ *                                                     '----'
+ *
+ *  (A) successor state of cur   (B) successor state of cur or it's entry
+ *      not yet traversed            are in current DFS path, thus cur and succ
+ *                                   are members of the same outermost loop
+ *
+ *                      initial                  initial
+ *                        |                        |
+ *                        V                        V
+ *                       ...                      ...
+ *                        |                        |
+ *                        V                        V
+ *                .------...               .------...
+ *                |       |                |       |
+ *                V       V                V       V
+ *           .-> hdr     ...              ...     ...
+ *           |    |       |                |       |
+ *           |    V       V                V       V
+ *           |   succ <- cur              succ <- cur
+ *           |    |                        |
+ *           |    V                        V
+ *           |   ...                      ...
+ *           |    |                        |
+ *           '----'                       exit
+ *
+ * (C) successor state of cur is a part of some loop but this loop
+ *     does not include cur or successor state is not in a loop at all.
+ *
+ * Algorithm could be described as the following python code:
+ *
+ *     traversed = set()   # Set of traversed nodes
+ *     entries = {}        # Mapping from node to loop entry
+ *     depths = {}         # Depth level assigned to graph node
+ *     path = set()        # Current DFS path
+ *
+ *     # Find outermost loop entry known for n
+ *     def get_loop_entry(n):
+ *         h = entries.get(n, None)
+ *         while h in entries and entries[h] != h:
+ *             h = entries[h]
+ *         return h
+ *
+ *     # Update n's loop entry if h's outermost entry comes
+ *     # before n's outermost entry in current DFS path.
+ *     def update_loop_entry(n, h):
+ *         n1 = get_loop_entry(n) or n
+ *         h1 = get_loop_entry(h) or h
+ *         if h1 in path and depths[h1] <= depths[n1]:
+ *             entries[n] = h1
+ *
+ *     def dfs(n, depth):
+ *         traversed.add(n)
+ *         path.add(n)
+ *         depths[n] = depth
+ *         for succ in G.successors(n):
+ *             if succ not in traversed:
+ *                 # Case A: explore succ and update cur's loop entry
+ *                 #         only if succ's entry is in current DFS path.
+ *                 dfs(succ, depth + 1)
+ *                 h = get_loop_entry(succ)
+ *                 update_loop_entry(n, h)
+ *             else:
+ *                 # Case B or C depending on `h1 in path` check in update_loop_entry().
+ *                 update_loop_entry(n, succ)
+ *         path.remove(n)
+ *
+ * To adapt this algorithm for use with verifier:
+ * - use st->branch == 0 as a signal that DFS of succ had been finished
+ *   and cur's loop entry has to be updated (case A), handle this in
+ *   update_branch_counts();
+ * - use st->branch > 0 as a signal that st is in the current DFS path;
+ * - handle cases B and C in is_state_visited();
+ * - update topmost loop entry for intermediate states in get_loop_entry().
+ */
+static struct bpf_verifier_state *get_loop_entry(struct bpf_verifier_state *st)
+{
+	struct bpf_verifier_state *topmost = st->loop_entry, *old;
+
+	while (topmost && topmost->loop_entry && topmost != topmost->loop_entry)
+		topmost = topmost->loop_entry;
+	/* Update loop entries for intermediate states to avoid this
+	 * traversal in future get_loop_entry() calls.
+	 */
+	while (st && st->loop_entry != topmost) {
+		old = st->loop_entry;
+		st->loop_entry = topmost;
+		st = old;
+	}
+	return topmost;
+}
+
+static void update_loop_entry(struct bpf_verifier_state *cur, struct bpf_verifier_state *hdr)
+{
+	struct bpf_verifier_state *cur1, *hdr1;
+
+	cur1 = get_loop_entry(cur) ?: cur;
+	hdr1 = get_loop_entry(hdr) ?: hdr;
+	/* The head1->branches check decides between cases B and C in
+	 * comment for get_loop_entry(). If hdr1->branches == 0 then
+	 * head's topmost loop entry is not in current DFS path,
+	 * hence 'cur' and 'hdr' are not in the same loop and there is
+	 * no need to update cur->loop_entry.
+	 */
+	if (hdr1->branches && hdr1->dfs_depth <= cur1->dfs_depth) {
+		cur->loop_entry = hdr;
+		hdr->used_as_loop_entry = true;
+	}
+}
+
+static void update_branch_counts(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+	while (st) {
+		u32 br = --st->branches;
+
+		/* br == 0 signals that DFS exploration for 'st' is finished,
+		 * thus it is necessary to update parent's loop entry if it
+		 * turned out that st is a part of some loop.
+		 * This is a part of 'case A' in get_loop_entry() comment.
+		 */
+		if (br == 0 && st->parent && st->loop_entry)
+			update_loop_entry(st->parent, st->loop_entry);
+
+		/* WARN_ON(br > 1) technically makes sense here,
+		 * but see comment in push_stack(), hence:
+		 */
+		WARN_ONCE((int)br < 0,
+			  "BUG update_branch_counts:branches_to_explore=%d\n",
+			  br);
+		if (br)
+			break;
+		st = st->parent;
+	}
+}
+
+static int pop_stack(struct bpf_verifier_env *env, int *prev_insn_idx,
+		     int *insn_idx, bool pop_log)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+	struct bpf_verifier_stack_elem *elem, *head = env->head;
+	int err;
+
+	if (env->head == NULL)
+		return -ENOENT;
+
+	if (cur) {
+		err = copy_verifier_state(cur, &head->st);
+		if (err)
+			return err;
+	}
+	if (pop_log)
+		bpf_vlog_reset(&env->log, head->log_pos);
+	if (insn_idx)
+		*insn_idx = head->insn_idx;
+	if (prev_insn_idx)
+		*prev_insn_idx = head->prev_insn_idx;
+	elem = head->next;
+	free_verifier_state(&head->st, false);
+	kfree(head);
+	env->head = elem;
+	env->stack_size--;
+	return 0;
+}
+
+static struct bpf_verifier_state *push_stack(struct bpf_verifier_env *env,
+					     int insn_idx, int prev_insn_idx,
+					     bool speculative)
+{
+	struct bpf_verifier_state *cur = env->cur_state;
+	struct bpf_verifier_stack_elem *elem;
+	int err;
+
+	elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
+	if (!elem)
+		goto err;
+
+	elem->insn_idx = insn_idx;
+	elem->prev_insn_idx = prev_insn_idx;
+	elem->next = env->head;
+	elem->log_pos = env->log.end_pos;
+	env->head = elem;
+	env->stack_size++;
+	err = copy_verifier_state(&elem->st, cur);
+	if (err)
+		goto err;
+	elem->st.speculative |= speculative;
+	if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
+		verbose(env, "The sequence of %d jumps is too complex.\n",
+			env->stack_size);
+		goto err;
+	}
+	if (elem->st.parent) {
+		++elem->st.parent->branches;
+		/* WARN_ON(branches > 2) technically makes sense here,
+		 * but
+		 * 1. speculative states will bump 'branches' for non-branch
+		 * instructions
+		 * 2. is_state_visited() heuristics may decide not to create
+		 * a new state for a sequence of branches and all such current
+		 * and cloned states will be pointing to a single parent state
+		 * which might have large 'branches' count.
+		 */
+	}
+	return &elem->st;
+err:
+	free_verifier_state(env->cur_state, true);
+	env->cur_state = NULL;
+	/* pop all elements and return */
+	while (!pop_stack(env, NULL, NULL, false));
+	return NULL;
+}
+
+#define CALLER_SAVED_REGS 6
+static const int caller_saved[CALLER_SAVED_REGS] = {
+	BPF_REG_0, BPF_REG_1, BPF_REG_2, BPF_REG_3, BPF_REG_4, BPF_REG_5
+};
+
+/* This helper doesn't clear reg->id */
+static void ___mark_reg_known(struct bpf_reg_state *reg, u64 imm)
+{
+	reg->var_off = tnum_const(imm);
+	reg->smin_value = (s64)imm;
+	reg->smax_value = (s64)imm;
+	reg->umin_value = imm;
+	reg->umax_value = imm;
+
+	reg->s32_min_value = (s32)imm;
+	reg->s32_max_value = (s32)imm;
+	reg->u32_min_value = (u32)imm;
+	reg->u32_max_value = (u32)imm;
+}
+
+/* Mark the unknown part of a register (variable offset or scalar value) as
+ * known to have the value @imm.
+ */
+static void __mark_reg_known(struct bpf_reg_state *reg, u64 imm)
+{
+	/* Clear off and union(map_ptr, range) */
+	memset(((u8 *)reg) + sizeof(reg->type), 0,
+	       offsetof(struct bpf_reg_state, var_off) - sizeof(reg->type));
+	reg->id = 0;
+	reg->ref_obj_id = 0;
+	___mark_reg_known(reg, imm);
+}
+
+static void __mark_reg32_known(struct bpf_reg_state *reg, u64 imm)
+{
+	reg->var_off = tnum_const_subreg(reg->var_off, imm);
+	reg->s32_min_value = (s32)imm;
+	reg->s32_max_value = (s32)imm;
+	reg->u32_min_value = (u32)imm;
+	reg->u32_max_value = (u32)imm;
+}
+
+/* Mark the 'variable offset' part of a register as zero.  This should be
+ * used only on registers holding a pointer type.
+ */
+static void __mark_reg_known_zero(struct bpf_reg_state *reg)
+{
+	__mark_reg_known(reg, 0);
+}
+
+static void __mark_reg_const_zero(struct bpf_reg_state *reg)
+{
+	__mark_reg_known(reg, 0);
+	reg->type = SCALAR_VALUE;
+}
+
+static void mark_reg_known_zero(struct bpf_verifier_env *env,
+				struct bpf_reg_state *regs, u32 regno)
+{
+	if (WARN_ON(regno >= MAX_BPF_REG)) {
+		verbose(env, "mark_reg_known_zero(regs, %u)\n", regno);
+		/* Something bad happened, let's kill all regs */
+		for (regno = 0; regno < MAX_BPF_REG; regno++)
+			__mark_reg_not_init(env, regs + regno);
+		return;
+	}
+	__mark_reg_known_zero(regs + regno);
+}
+
+static void __mark_dynptr_reg(struct bpf_reg_state *reg, enum bpf_dynptr_type type,
+			      bool first_slot, int dynptr_id)
+{
+	/* reg->type has no meaning for STACK_DYNPTR, but when we set reg for
+	 * callback arguments, it does need to be CONST_PTR_TO_DYNPTR, so simply
+	 * set it unconditionally as it is ignored for STACK_DYNPTR anyway.
+	 */
+	__mark_reg_known_zero(reg);
+	reg->type = CONST_PTR_TO_DYNPTR;
+	/* Give each dynptr a unique id to uniquely associate slices to it. */
+	reg->id = dynptr_id;
+	reg->dynptr.type = type;
+	reg->dynptr.first_slot = first_slot;
+}
+
+static void mark_ptr_not_null_reg(struct bpf_reg_state *reg)
+{
+	if (base_type(reg->type) == PTR_TO_MAP_VALUE) {
+		const struct bpf_map *map = reg->map_ptr;
+
+		if (map->inner_map_meta) {
+			reg->type = CONST_PTR_TO_MAP;
+			reg->map_ptr = map->inner_map_meta;
+			/* transfer reg's id which is unique for every map_lookup_elem
+			 * as UID of the inner map.
+			 */
+			if (btf_record_has_field(map->inner_map_meta->record, BPF_TIMER))
+				reg->map_uid = reg->id;
+		} else if (map->map_type == BPF_MAP_TYPE_XSKMAP) {
+			reg->type = PTR_TO_XDP_SOCK;
+		} else if (map->map_type == BPF_MAP_TYPE_SOCKMAP ||
+			   map->map_type == BPF_MAP_TYPE_SOCKHASH) {
+			reg->type = PTR_TO_SOCKET;
+		} else {
+			reg->type = PTR_TO_MAP_VALUE;
+		}
+		return;
+	}
+
+	reg->type &= ~PTR_MAYBE_NULL;
+}
+
+static void mark_reg_graph_node(struct bpf_reg_state *regs, u32 regno,
+				struct btf_field_graph_root *ds_head)
+{
+	__mark_reg_known_zero(&regs[regno]);
+	regs[regno].type = PTR_TO_BTF_ID | MEM_ALLOC;
+	regs[regno].btf = ds_head->btf;
+	regs[regno].btf_id = ds_head->value_btf_id;
+	regs[regno].off = ds_head->node_offset;
+}
+
+static bool reg_is_pkt_pointer(const struct bpf_reg_state *reg)
+{
+	return type_is_pkt_pointer(reg->type);
+}
+
+static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
+{
+	return reg_is_pkt_pointer(reg) ||
+	       reg->type == PTR_TO_PACKET_END;
+}
+
+static bool reg_is_dynptr_slice_pkt(const struct bpf_reg_state *reg)
+{
+	return base_type(reg->type) == PTR_TO_MEM &&
+		(reg->type & DYNPTR_TYPE_SKB || reg->type & DYNPTR_TYPE_XDP);
+}
+
+/* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
+static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
+				    enum bpf_reg_type which)
+{
+	/* The register can already have a range from prior markings.
+	 * This is fine as long as it hasn't been advanced from its
+	 * origin.
+	 */
+	return reg->type == which &&
+	       reg->id == 0 &&
+	       reg->off == 0 &&
+	       tnum_equals_const(reg->var_off, 0);
+}
+
+/* Reset the min/max bounds of a register */
+static void __mark_reg_unbounded(struct bpf_reg_state *reg)
+{
+	reg->smin_value = S64_MIN;
+	reg->smax_value = S64_MAX;
+	reg->umin_value = 0;
+	reg->umax_value = U64_MAX;
+
+	reg->s32_min_value = S32_MIN;
+	reg->s32_max_value = S32_MAX;
+	reg->u32_min_value = 0;
+	reg->u32_max_value = U32_MAX;
+}
+
+static void __mark_reg64_unbounded(struct bpf_reg_state *reg)
+{
+	reg->smin_value = S64_MIN;
+	reg->smax_value = S64_MAX;
+	reg->umin_value = 0;
+	reg->umax_value = U64_MAX;
+}
+
+static void __mark_reg32_unbounded(struct bpf_reg_state *reg)
+{
+	reg->s32_min_value = S32_MIN;
+	reg->s32_max_value = S32_MAX;
+	reg->u32_min_value = 0;
+	reg->u32_max_value = U32_MAX;
+}
+
+static void __update_reg32_bounds(struct bpf_reg_state *reg)
+{
+	struct tnum var32_off = tnum_subreg(reg->var_off);
+
+	/* min signed is max(sign bit) | min(other bits) */
+	reg->s32_min_value = max_t(s32, reg->s32_min_value,
+			var32_off.value | (var32_off.mask & S32_MIN));
+	/* max signed is min(sign bit) | max(other bits) */
+	reg->s32_max_value = min_t(s32, reg->s32_max_value,
+			var32_off.value | (var32_off.mask & S32_MAX));
+	reg->u32_min_value = max_t(u32, reg->u32_min_value, (u32)var32_off.value);
+	reg->u32_max_value = min(reg->u32_max_value,
+				 (u32)(var32_off.value | var32_off.mask));
+}
+
+static void __update_reg64_bounds(struct bpf_reg_state *reg)
+{
+	/* min signed is max(sign bit) | min(other bits) */
+	reg->smin_value = max_t(s64, reg->smin_value,
+				reg->var_off.value | (reg->var_off.mask & S64_MIN));
+	/* max signed is min(sign bit) | max(other bits) */
+	reg->smax_value = min_t(s64, reg->smax_value,
+				reg->var_off.value | (reg->var_off.mask & S64_MAX));
+	reg->umin_value = max(reg->umin_value, reg->var_off.value);
+	reg->umax_value = min(reg->umax_value,
+			      reg->var_off.value | reg->var_off.mask);
+}
+
+static void __update_reg_bounds(struct bpf_reg_state *reg)
+{
+	__update_reg32_bounds(reg);
+	__update_reg64_bounds(reg);
+}
+
+/* Uses signed min/max values to inform unsigned, and vice-versa */
+static void __reg32_deduce_bounds(struct bpf_reg_state *reg)
+{
+	/* Learn sign from signed bounds.
+	 * If we cannot cross the sign boundary, then signed and unsigned bounds
+	 * are the same, so combine.  This works even in the negative case, e.g.
+	 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
+	 */
+	if (reg->s32_min_value >= 0 || reg->s32_max_value < 0) {
+		reg->s32_min_value = reg->u32_min_value =
+			max_t(u32, reg->s32_min_value, reg->u32_min_value);
+		reg->s32_max_value = reg->u32_max_value =
+			min_t(u32, reg->s32_max_value, reg->u32_max_value);
+		return;
+	}
+	/* Learn sign from unsigned bounds.  Signed bounds cross the sign
+	 * boundary, so we must be careful.
+	 */
+	if ((s32)reg->u32_max_value >= 0) {
+		/* Positive.  We can't learn anything from the smin, but smax
+		 * is positive, hence safe.
+		 */
+		reg->s32_min_value = reg->u32_min_value;
+		reg->s32_max_value = reg->u32_max_value =
+			min_t(u32, reg->s32_max_value, reg->u32_max_value);
+	} else if ((s32)reg->u32_min_value < 0) {
+		/* Negative.  We can't learn anything from the smax, but smin
+		 * is negative, hence safe.
+		 */
+		reg->s32_min_value = reg->u32_min_value =
+			max_t(u32, reg->s32_min_value, reg->u32_min_value);
+		reg->s32_max_value = reg->u32_max_value;
+	}
+}
+
+static void __reg64_deduce_bounds(struct bpf_reg_state *reg)
+{
+	/* Learn sign from signed bounds.
+	 * If we cannot cross the sign boundary, then signed and unsigned bounds
+	 * are the same, so combine.  This works even in the negative case, e.g.
+	 * -3 s<= x s<= -1 implies 0xf...fd u<= x u<= 0xf...ff.
+	 */
+	if (reg->smin_value >= 0 || reg->smax_value < 0) {
+		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
+							  reg->umin_value);
+		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
+							  reg->umax_value);
+		return;
+	}
+	/* Learn sign from unsigned bounds.  Signed bounds cross the sign
+	 * boundary, so we must be careful.
+	 */
+	if ((s64)reg->umax_value >= 0) {
+		/* Positive.  We can't learn anything from the smin, but smax
+		 * is positive, hence safe.
+		 */
+		reg->smin_value = reg->umin_value;
+		reg->smax_value = reg->umax_value = min_t(u64, reg->smax_value,
+							  reg->umax_value);
+	} else if ((s64)reg->umin_value < 0) {
+		/* Negative.  We can't learn anything from the smax, but smin
+		 * is negative, hence safe.
+		 */
+		reg->smin_value = reg->umin_value = max_t(u64, reg->smin_value,
+							  reg->umin_value);
+		reg->smax_value = reg->umax_value;
+	}
+}
+
+static void __reg_deduce_bounds(struct bpf_reg_state *reg)
+{
+	__reg32_deduce_bounds(reg);
+	__reg64_deduce_bounds(reg);
+}
+
+/* Attempts to improve var_off based on unsigned min/max information */
+static void __reg_bound_offset(struct bpf_reg_state *reg)
+{
+	struct tnum var64_off = tnum_intersect(reg->var_off,
+					       tnum_range(reg->umin_value,
+							  reg->umax_value));
+	struct tnum var32_off = tnum_intersect(tnum_subreg(var64_off),
+					       tnum_range(reg->u32_min_value,
+							  reg->u32_max_value));
+
+	reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off);
+}
+
+static void reg_bounds_sync(struct bpf_reg_state *reg)
+{
+	/* We might have learned new bounds from the var_off. */
+	__update_reg_bounds(reg);
+	/* We might have learned something about the sign bit. */
+	__reg_deduce_bounds(reg);
+	/* We might have learned some bits from the bounds. */
+	__reg_bound_offset(reg);
+	/* Intersecting with the old var_off might have improved our bounds
+	 * slightly, e.g. if umax was 0x7f...f and var_off was (0; 0xf...fc),
+	 * then new var_off is (0; 0x7f...fc) which improves our umax.
+	 */
+	__update_reg_bounds(reg);
+}
+
+static bool __reg32_bound_s64(s32 a)
+{
+	return a >= 0 && a <= S32_MAX;
+}
+
+static void __reg_assign_32_into_64(struct bpf_reg_state *reg)
+{
+	reg->umin_value = reg->u32_min_value;
+	reg->umax_value = reg->u32_max_value;
+
+	/* Attempt to pull 32-bit signed bounds into 64-bit bounds but must
+	 * be positive otherwise set to worse case bounds and refine later
+	 * from tnum.
+	 */
+	if (__reg32_bound_s64(reg->s32_min_value) &&
+	    __reg32_bound_s64(reg->s32_max_value)) {
+		reg->smin_value = reg->s32_min_value;
+		reg->smax_value = reg->s32_max_value;
+	} else {
+		reg->smin_value = 0;
+		reg->smax_value = U32_MAX;
+	}
+}
+
+static void __reg_combine_32_into_64(struct bpf_reg_state *reg)
+{
+	/* special case when 64-bit register has upper 32-bit register
+	 * zeroed. Typically happens after zext or <<32, >>32 sequence
+	 * allowing us to use 32-bit bounds directly,
+	 */
+	if (tnum_equals_const(tnum_clear_subreg(reg->var_off), 0)) {
+		__reg_assign_32_into_64(reg);
+	} else {
+		/* Otherwise the best we can do is push lower 32bit known and
+		 * unknown bits into register (var_off set from jmp logic)
+		 * then learn as much as possible from the 64-bit tnum
+		 * known and unknown bits. The previous smin/smax bounds are
+		 * invalid here because of jmp32 compare so mark them unknown
+		 * so they do not impact tnum bounds calculation.
+		 */
+		__mark_reg64_unbounded(reg);
+	}
+	reg_bounds_sync(reg);
+}
+
+static bool __reg64_bound_s32(s64 a)
+{
+	return a >= S32_MIN && a <= S32_MAX;
+}
+
+static bool __reg64_bound_u32(u64 a)
+{
+	return a >= U32_MIN && a <= U32_MAX;
+}
+
+static void __reg_combine_64_into_32(struct bpf_reg_state *reg)
+{
+	__mark_reg32_unbounded(reg);
+	if (__reg64_bound_s32(reg->smin_value) && __reg64_bound_s32(reg->smax_value)) {
+		reg->s32_min_value = (s32)reg->smin_value;
+		reg->s32_max_value = (s32)reg->smax_value;
+	}
+	if (__reg64_bound_u32(reg->umin_value) && __reg64_bound_u32(reg->umax_value)) {
+		reg->u32_min_value = (u32)reg->umin_value;
+		reg->u32_max_value = (u32)reg->umax_value;
+	}
+	reg_bounds_sync(reg);
+}
+
+/* Mark a register as having a completely unknown (scalar) value. */
+static void __mark_reg_unknown(const struct bpf_verifier_env *env,
+			       struct bpf_reg_state *reg)
+{
+	/*
+	 * Clear type, off, and union(map_ptr, range) and
+	 * padding between 'type' and union
+	 */
+	memset(reg, 0, offsetof(struct bpf_reg_state, var_off));
+	reg->type = SCALAR_VALUE;
+	reg->id = 0;
+	reg->ref_obj_id = 0;
+	reg->var_off = tnum_unknown;
+	reg->frameno = 0;
+	reg->precise = !env->bpf_capable;
+	__mark_reg_unbounded(reg);
+}
+
+static void mark_reg_unknown(struct bpf_verifier_env *env,
+			     struct bpf_reg_state *regs, u32 regno)
+{
+	if (WARN_ON(regno >= MAX_BPF_REG)) {
+		verbose(env, "mark_reg_unknown(regs, %u)\n", regno);
+		/* Something bad happened, let's kill all regs except FP */
+		for (regno = 0; regno < BPF_REG_FP; regno++)
+			__mark_reg_not_init(env, regs + regno);
+		return;
+	}
+	__mark_reg_unknown(env, regs + regno);
+}
+
+static void __mark_reg_not_init(const struct bpf_verifier_env *env,
+				struct bpf_reg_state *reg)
+{
+	__mark_reg_unknown(env, reg);
+	reg->type = NOT_INIT;
+}
+
+static void mark_reg_not_init(struct bpf_verifier_env *env,
+			      struct bpf_reg_state *regs, u32 regno)
+{
+	if (WARN_ON(regno >= MAX_BPF_REG)) {
+		verbose(env, "mark_reg_not_init(regs, %u)\n", regno);
+		/* Something bad happened, let's kill all regs except FP */
+		for (regno = 0; regno < BPF_REG_FP; regno++)
+			__mark_reg_not_init(env, regs + regno);
+		return;
+	}
+	__mark_reg_not_init(env, regs + regno);
+}
+
+static void mark_btf_ld_reg(struct bpf_verifier_env *env,
+			    struct bpf_reg_state *regs, u32 regno,
+			    enum bpf_reg_type reg_type,
+			    struct btf *btf, u32 btf_id,
+			    enum bpf_type_flag flag)
+{
+	if (reg_type == SCALAR_VALUE) {
+		mark_reg_unknown(env, regs, regno);
+		return;
+	}
+	mark_reg_known_zero(env, regs, regno);
+	regs[regno].type = PTR_TO_BTF_ID | flag;
+	regs[regno].btf = btf;
+	regs[regno].btf_id = btf_id;
+}
+
+#define DEF_NOT_SUBREG	(0)
+static void init_reg_state(struct bpf_verifier_env *env,
+			   struct bpf_func_state *state)
+{
+	struct bpf_reg_state *regs = state->regs;
+	int i;
+
+	for (i = 0; i < MAX_BPF_REG; i++) {
+		mark_reg_not_init(env, regs, i);
+		regs[i].live = REG_LIVE_NONE;
+		regs[i].parent = NULL;
+		regs[i].subreg_def = DEF_NOT_SUBREG;
+	}
+
+	/* frame pointer */
+	regs[BPF_REG_FP].type = PTR_TO_STACK;
+	mark_reg_known_zero(env, regs, BPF_REG_FP);
+	regs[BPF_REG_FP].frameno = state->frameno;
+}
+
+#define BPF_MAIN_FUNC (-1)
+static void init_func_state(struct bpf_verifier_env *env,
+			    struct bpf_func_state *state,
+			    int callsite, int frameno, int subprogno)
+{
+	state->callsite = callsite;
+	state->frameno = frameno;
+	state->subprogno = subprogno;
+	state->callback_ret_range = tnum_range(0, 0);
+	init_reg_state(env, state);
+	mark_verifier_state_scratched(env);
+}
+
+/* Similar to push_stack(), but for async callbacks */
+static struct bpf_verifier_state *push_async_cb(struct bpf_verifier_env *env,
+						int insn_idx, int prev_insn_idx,
+						int subprog)
+{
+	struct bpf_verifier_stack_elem *elem;
+	struct bpf_func_state *frame;
+
+	elem = kzalloc(sizeof(struct bpf_verifier_stack_elem), GFP_KERNEL);
+	if (!elem)
+		goto err;
+
+	elem->insn_idx = insn_idx;
+	elem->prev_insn_idx = prev_insn_idx;
+	elem->next = env->head;
+	elem->log_pos = env->log.end_pos;
+	env->head = elem;
+	env->stack_size++;
+	if (env->stack_size > BPF_COMPLEXITY_LIMIT_JMP_SEQ) {
+		verbose(env,
+			"The sequence of %d jumps is too complex for async cb.\n",
+			env->stack_size);
+		goto err;
+	}
+	/* Unlike push_stack() do not copy_verifier_state().
+	 * The caller state doesn't matter.
+	 * This is async callback. It starts in a fresh stack.
+	 * Initialize it similar to do_check_common().
+	 */
+	elem->st.branches = 1;
+	frame = kzalloc(sizeof(*frame), GFP_KERNEL);
+	if (!frame)
+		goto err;
+	init_func_state(env, frame,
+			BPF_MAIN_FUNC /* callsite */,
+			0 /* frameno within this callchain */,
+			subprog /* subprog number within this prog */);
+	elem->st.frame[0] = frame;
+	return &elem->st;
+err:
+	free_verifier_state(env->cur_state, true);
+	env->cur_state = NULL;
+	/* pop all elements and return */
+	while (!pop_stack(env, NULL, NULL, false));
+	return NULL;
+}
+
+
+enum reg_arg_type {
+	SRC_OP,		/* register is used as source operand */
+	DST_OP,		/* register is used as destination operand */
+	DST_OP_NO_MARK	/* same as above, check only, don't mark */
+};
+
+static int cmp_subprogs(const void *a, const void *b)
+{
+	return ((struct bpf_subprog_info *)a)->start -
+	       ((struct bpf_subprog_info *)b)->start;
+}
+
+static int find_subprog(struct bpf_verifier_env *env, int off)
+{
+	struct bpf_subprog_info *p;
+
+	p = bsearch(&off, env->subprog_info, env->subprog_cnt,
+		    sizeof(env->subprog_info[0]), cmp_subprogs);
+	if (!p)
+		return -ENOENT;
+	return p - env->subprog_info;
+
+}
+
+static int add_subprog(struct bpf_verifier_env *env, int off)
+{
+	int insn_cnt = env->prog->len;
+	int ret;
+
+	if (off >= insn_cnt || off < 0) {
+		verbose(env, "call to invalid destination\n");
+		return -EINVAL;
+	}
+	ret = find_subprog(env, off);
+	if (ret >= 0)
+		return ret;
+	if (env->subprog_cnt >= BPF_MAX_SUBPROGS) {
+		verbose(env, "too many subprograms\n");
+		return -E2BIG;
+	}
+	/* determine subprog starts. The end is one before the next starts */
+	env->subprog_info[env->subprog_cnt++].start = off;
+	sort(env->subprog_info, env->subprog_cnt,
+	     sizeof(env->subprog_info[0]), cmp_subprogs, NULL);
+	return env->subprog_cnt - 1;
+}
+
+#define MAX_KFUNC_DESCS 256
+#define MAX_KFUNC_BTFS	256
+
+struct bpf_kfunc_desc {
+	struct btf_func_model func_model;
+	u32 func_id;
+	s32 imm;
+	u16 offset;
+	unsigned long addr;
+};
+
+struct bpf_kfunc_btf {
+	struct btf *btf;
+	struct module *module;
+	u16 offset;
+};
+
+struct bpf_kfunc_desc_tab {
+	/* Sorted by func_id (BTF ID) and offset (fd_array offset) during
+	 * verification. JITs do lookups by bpf_insn, where func_id may not be
+	 * available, therefore at the end of verification do_misc_fixups()
+	 * sorts this by imm and offset.
+	 */
+	struct bpf_kfunc_desc descs[MAX_KFUNC_DESCS];
+	u32 nr_descs;
+};
+
+struct bpf_kfunc_btf_tab {
+	struct bpf_kfunc_btf descs[MAX_KFUNC_BTFS];
+	u32 nr_descs;
+};
+
+static int kfunc_desc_cmp_by_id_off(const void *a, const void *b)
+{
+	const struct bpf_kfunc_desc *d0 = a;
+	const struct bpf_kfunc_desc *d1 = b;
+
+	/* func_id is not greater than BTF_MAX_TYPE */
+	return d0->func_id - d1->func_id ?: d0->offset - d1->offset;
+}
+
+static int kfunc_btf_cmp_by_off(const void *a, const void *b)
+{
+	const struct bpf_kfunc_btf *d0 = a;
+	const struct bpf_kfunc_btf *d1 = b;
+
+	return d0->offset - d1->offset;
+}
+
+static const struct bpf_kfunc_desc *
+find_kfunc_desc(const struct bpf_prog *prog, u32 func_id, u16 offset)
+{
+	struct bpf_kfunc_desc desc = {
+		.func_id = func_id,
+		.offset = offset,
+	};
+	struct bpf_kfunc_desc_tab *tab;
+
+	tab = prog->aux->kfunc_tab;
+	return bsearch(&desc, tab->descs, tab->nr_descs,
+		       sizeof(tab->descs[0]), kfunc_desc_cmp_by_id_off);
+}
+
+int bpf_get_kfunc_addr(const struct bpf_prog *prog, u32 func_id,
+		       u16 btf_fd_idx, u8 **func_addr)
+{
+	const struct bpf_kfunc_desc *desc;
+
+	desc = find_kfunc_desc(prog, func_id, btf_fd_idx);
+	if (!desc)
+		return -EFAULT;
+
+	*func_addr = (u8 *)desc->addr;
+	return 0;
+}
+
+static struct btf *__find_kfunc_desc_btf(struct bpf_verifier_env *env,
+					 s16 offset)
+{
+	struct bpf_kfunc_btf kf_btf = { .offset = offset };
+	struct bpf_kfunc_btf_tab *tab;
+	struct bpf_kfunc_btf *b;
+	struct module *mod;
+	struct btf *btf;
+	int btf_fd;
+
+	tab = env->prog->aux->kfunc_btf_tab;
+	b = bsearch(&kf_btf, tab->descs, tab->nr_descs,
+		    sizeof(tab->descs[0]), kfunc_btf_cmp_by_off);
+	if (!b) {
+		if (tab->nr_descs == MAX_KFUNC_BTFS) {
+			verbose(env, "too many different module BTFs\n");
+			return ERR_PTR(-E2BIG);
+		}
+
+		if (bpfptr_is_null(env->fd_array)) {
+			verbose(env, "kfunc offset > 0 without fd_array is invalid\n");
+			return ERR_PTR(-EPROTO);
+		}
+
+		if (copy_from_bpfptr_offset(&btf_fd, env->fd_array,
+					    offset * sizeof(btf_fd),
+					    sizeof(btf_fd)))
+			return ERR_PTR(-EFAULT);
+
+		btf = btf_get_by_fd(btf_fd);
+		if (IS_ERR(btf)) {
+			verbose(env, "invalid module BTF fd specified\n");
+			return btf;
+		}
+
+		if (!btf_is_module(btf)) {
+			verbose(env, "BTF fd for kfunc is not a module BTF\n");
+			btf_put(btf);
+			return ERR_PTR(-EINVAL);
+		}
+
+		mod = btf_try_get_module(btf);
+		if (!mod) {
+			btf_put(btf);
+			return ERR_PTR(-ENXIO);
+		}
+
+		b = &tab->descs[tab->nr_descs++];
+		b->btf = btf;
+		b->module = mod;
+		b->offset = offset;
+
+		sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+		     kfunc_btf_cmp_by_off, NULL);
+	}
+	return b->btf;
+}
+
+void bpf_free_kfunc_btf_tab(struct bpf_kfunc_btf_tab *tab)
+{
+	if (!tab)
+		return;
+
+	while (tab->nr_descs--) {
+		module_put(tab->descs[tab->nr_descs].module);
+		btf_put(tab->descs[tab->nr_descs].btf);
+	}
+	kfree(tab);
+}
+
+static struct btf *find_kfunc_desc_btf(struct bpf_verifier_env *env, s16 offset)
+{
+	if (offset) {
+		if (offset < 0) {
+			/* In the future, this can be allowed to increase limit
+			 * of fd index into fd_array, interpreted as u16.
+			 */
+			verbose(env, "negative offset disallowed for kernel module function call\n");
+			return ERR_PTR(-EINVAL);
+		}
+
+		return __find_kfunc_desc_btf(env, offset);
+	}
+	return btf_vmlinux ?: ERR_PTR(-ENOENT);
+}
+
+static int add_kfunc_call(struct bpf_verifier_env *env, u32 func_id, s16 offset)
+{
+	const struct btf_type *func, *func_proto;
+	struct bpf_kfunc_btf_tab *btf_tab;
+	struct bpf_kfunc_desc_tab *tab;
+	struct bpf_prog_aux *prog_aux;
+	struct bpf_kfunc_desc *desc;
+	const char *func_name;
+	struct btf *desc_btf;
+	unsigned long call_imm;
+	unsigned long addr;
+	int err;
+
+	prog_aux = env->prog->aux;
+	tab = prog_aux->kfunc_tab;
+	btf_tab = prog_aux->kfunc_btf_tab;
+	if (!tab) {
+		if (!btf_vmlinux) {
+			verbose(env, "calling kernel function is not supported without CONFIG_DEBUG_INFO_BTF\n");
+			return -ENOTSUPP;
+		}
+
+		if (!env->prog->jit_requested) {
+			verbose(env, "JIT is required for calling kernel function\n");
+			return -ENOTSUPP;
+		}
+
+		if (!bpf_jit_supports_kfunc_call()) {
+			verbose(env, "JIT does not support calling kernel function\n");
+			return -ENOTSUPP;
+		}
+
+		if (!env->prog->gpl_compatible) {
+			verbose(env, "cannot call kernel function from non-GPL compatible program\n");
+			return -EINVAL;
+		}
+
+		tab = kzalloc(sizeof(*tab), GFP_KERNEL);
+		if (!tab)
+			return -ENOMEM;
+		prog_aux->kfunc_tab = tab;
+	}
+
+	/* func_id == 0 is always invalid, but instead of returning an error, be
+	 * conservative and wait until the code elimination pass before returning
+	 * error, so that invalid calls that get pruned out can be in BPF programs
+	 * loaded from userspace.  It is also required that offset be untouched
+	 * for such calls.
+	 */
+	if (!func_id && !offset)
+		return 0;
+
+	if (!btf_tab && offset) {
+		btf_tab = kzalloc(sizeof(*btf_tab), GFP_KERNEL);
+		if (!btf_tab)
+			return -ENOMEM;
+		prog_aux->kfunc_btf_tab = btf_tab;
+	}
+
+	desc_btf = find_kfunc_desc_btf(env, offset);
+	if (IS_ERR(desc_btf)) {
+		verbose(env, "failed to find BTF for kernel function\n");
+		return PTR_ERR(desc_btf);
+	}
+
+	if (find_kfunc_desc(env->prog, func_id, offset))
+		return 0;
+
+	if (tab->nr_descs == MAX_KFUNC_DESCS) {
+		verbose(env, "too many different kernel function calls\n");
+		return -E2BIG;
+	}
+
+	func = btf_type_by_id(desc_btf, func_id);
+	if (!func || !btf_type_is_func(func)) {
+		verbose(env, "kernel btf_id %u is not a function\n",
+			func_id);
+		return -EINVAL;
+	}
+	func_proto = btf_type_by_id(desc_btf, func->type);
+	if (!func_proto || !btf_type_is_func_proto(func_proto)) {
+		verbose(env, "kernel function btf_id %u does not have a valid func_proto\n",
+			func_id);
+		return -EINVAL;
+	}
+
+	func_name = btf_name_by_offset(desc_btf, func->name_off);
+	addr = kallsyms_lookup_name(func_name);
+	if (!addr) {
+		verbose(env, "cannot find address for kernel function %s\n",
+			func_name);
+		return -EINVAL;
+	}
+	specialize_kfunc(env, func_id, offset, &addr);
+
+	if (bpf_jit_supports_far_kfunc_call()) {
+		call_imm = func_id;
+	} else {
+		call_imm = BPF_CALL_IMM(addr);
+		/* Check whether the relative offset overflows desc->imm */
+		if ((unsigned long)(s32)call_imm != call_imm) {
+			verbose(env, "address of kernel function %s is out of range\n",
+				func_name);
+			return -EINVAL;
+		}
+	}
+
+	if (bpf_dev_bound_kfunc_id(func_id)) {
+		err = bpf_dev_bound_kfunc_check(&env->log, prog_aux);
+		if (err)
+			return err;
+	}
+
+	desc = &tab->descs[tab->nr_descs++];
+	desc->func_id = func_id;
+	desc->imm = call_imm;
+	desc->offset = offset;
+	desc->addr = addr;
+	err = btf_distill_func_proto(&env->log, desc_btf,
+				     func_proto, func_name,
+				     &desc->func_model);
+	if (!err)
+		sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+		     kfunc_desc_cmp_by_id_off, NULL);
+	return err;
+}
+
+static int kfunc_desc_cmp_by_imm_off(const void *a, const void *b)
+{
+	const struct bpf_kfunc_desc *d0 = a;
+	const struct bpf_kfunc_desc *d1 = b;
+
+	if (d0->imm != d1->imm)
+		return d0->imm < d1->imm ? -1 : 1;
+	if (d0->offset != d1->offset)
+		return d0->offset < d1->offset ? -1 : 1;
+	return 0;
+}
+
+static void sort_kfunc_descs_by_imm_off(struct bpf_prog *prog)
+{
+	struct bpf_kfunc_desc_tab *tab;
+
+	tab = prog->aux->kfunc_tab;
+	if (!tab)
+		return;
+
+	sort(tab->descs, tab->nr_descs, sizeof(tab->descs[0]),
+	     kfunc_desc_cmp_by_imm_off, NULL);
+}
+
+bool bpf_prog_has_kfunc_call(const struct bpf_prog *prog)
+{
+	return !!prog->aux->kfunc_tab;
+}
+
+const struct btf_func_model *
+bpf_jit_find_kfunc_model(const struct bpf_prog *prog,
+			 const struct bpf_insn *insn)
+{
+	const struct bpf_kfunc_desc desc = {
+		.imm = insn->imm,
+		.offset = insn->off,
+	};
+	const struct bpf_kfunc_desc *res;
+	struct bpf_kfunc_desc_tab *tab;
+
+	tab = prog->aux->kfunc_tab;
+	res = bsearch(&desc, tab->descs, tab->nr_descs,
+		      sizeof(tab->descs[0]), kfunc_desc_cmp_by_imm_off);
+
+	return res ? &res->func_model : NULL;
+}
+
+static int add_subprog_and_kfunc(struct bpf_verifier_env *env)
+{
+	struct bpf_subprog_info *subprog = env->subprog_info;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int i, ret, insn_cnt = env->prog->len;
+
+	/* Add entry function. */
+	ret = add_subprog(env, 0);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn) &&
+		    !bpf_pseudo_kfunc_call(insn))
+			continue;
+
+		if (!env->bpf_capable) {
+			verbose(env, "loading/calling other bpf or kernel functions are allowed for CAP_BPF and CAP_SYS_ADMIN\n");
+			return -EPERM;
+		}
+
+		if (bpf_pseudo_func(insn) || bpf_pseudo_call(insn))
+			ret = add_subprog(env, i + insn->imm + 1);
+		else
+			ret = add_kfunc_call(env, insn->imm, insn->off);
+
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Add a fake 'exit' subprog which could simplify subprog iteration
+	 * logic. 'subprog_cnt' should not be increased.
+	 */
+	subprog[env->subprog_cnt].start = insn_cnt;
+
+	if (env->log.level & BPF_LOG_LEVEL2)
+		for (i = 0; i < env->subprog_cnt; i++)
+			verbose(env, "func#%d @%d\n", i, subprog[i].start);
+
+	return 0;
+}
+
+static int check_subprogs(struct bpf_verifier_env *env)
+{
+	int i, subprog_start, subprog_end, off, cur_subprog = 0;
+	struct bpf_subprog_info *subprog = env->subprog_info;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+
+	/* now check that all jumps are within the same subprog */
+	subprog_start = subprog[cur_subprog].start;
+	subprog_end = subprog[cur_subprog + 1].start;
+	for (i = 0; i < insn_cnt; i++) {
+		u8 code = insn[i].code;
+
+		if (code == (BPF_JMP | BPF_CALL) &&
+		    insn[i].src_reg == 0 &&
+		    insn[i].imm == BPF_FUNC_tail_call)
+			subprog[cur_subprog].has_tail_call = true;
+		if (BPF_CLASS(code) == BPF_LD &&
+		    (BPF_MODE(code) == BPF_ABS || BPF_MODE(code) == BPF_IND))
+			subprog[cur_subprog].has_ld_abs = true;
+		if (BPF_CLASS(code) != BPF_JMP && BPF_CLASS(code) != BPF_JMP32)
+			goto next;
+		if (BPF_OP(code) == BPF_EXIT || BPF_OP(code) == BPF_CALL)
+			goto next;
+		if (code == (BPF_JMP32 | BPF_JA))
+			off = i + insn[i].imm + 1;
+		else
+			off = i + insn[i].off + 1;
+		if (off < subprog_start || off >= subprog_end) {
+			verbose(env, "jump out of range from insn %d to %d\n", i, off);
+			return -EINVAL;
+		}
+next:
+		if (i == subprog_end - 1) {
+			/* to avoid fall-through from one subprog into another
+			 * the last insn of the subprog should be either exit
+			 * or unconditional jump back
+			 */
+			if (code != (BPF_JMP | BPF_EXIT) &&
+			    code != (BPF_JMP32 | BPF_JA) &&
+			    code != (BPF_JMP | BPF_JA)) {
+				verbose(env, "last insn is not an exit or jmp\n");
+				return -EINVAL;
+			}
+			subprog_start = subprog_end;
+			cur_subprog++;
+			if (cur_subprog < env->subprog_cnt)
+				subprog_end = subprog[cur_subprog + 1].start;
+		}
+	}
+	return 0;
+}
+
+/* Parentage chain of this register (or stack slot) should take care of all
+ * issues like callee-saved registers, stack slot allocation time, etc.
+ */
+static int mark_reg_read(struct bpf_verifier_env *env,
+			 const struct bpf_reg_state *state,
+			 struct bpf_reg_state *parent, u8 flag)
+{
+	bool writes = parent == state->parent; /* Observe write marks */
+	int cnt = 0;
+
+	while (parent) {
+		/* if read wasn't screened by an earlier write ... */
+		if (writes && state->live & REG_LIVE_WRITTEN)
+			break;
+		if (parent->live & REG_LIVE_DONE) {
+			verbose(env, "verifier BUG type %s var_off %lld off %d\n",
+				reg_type_str(env, parent->type),
+				parent->var_off.value, parent->off);
+			return -EFAULT;
+		}
+		/* The first condition is more likely to be true than the
+		 * second, checked it first.
+		 */
+		if ((parent->live & REG_LIVE_READ) == flag ||
+		    parent->live & REG_LIVE_READ64)
+			/* The parentage chain never changes and
+			 * this parent was already marked as LIVE_READ.
+			 * There is no need to keep walking the chain again and
+			 * keep re-marking all parents as LIVE_READ.
+			 * This case happens when the same register is read
+			 * multiple times without writes into it in-between.
+			 * Also, if parent has the stronger REG_LIVE_READ64 set,
+			 * then no need to set the weak REG_LIVE_READ32.
+			 */
+			break;
+		/* ... then we depend on parent's value */
+		parent->live |= flag;
+		/* REG_LIVE_READ64 overrides REG_LIVE_READ32. */
+		if (flag == REG_LIVE_READ64)
+			parent->live &= ~REG_LIVE_READ32;
+		state = parent;
+		parent = state->parent;
+		writes = true;
+		cnt++;
+	}
+
+	if (env->longest_mark_read_walk < cnt)
+		env->longest_mark_read_walk = cnt;
+	return 0;
+}
+
+static int mark_dynptr_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi, ret;
+
+	/* For CONST_PTR_TO_DYNPTR, it must have already been done by
+	 * check_reg_arg in check_helper_call and mark_btf_func_reg_size in
+	 * check_kfunc_call.
+	 */
+	if (reg->type == CONST_PTR_TO_DYNPTR)
+		return 0;
+	spi = dynptr_get_spi(env, reg);
+	if (spi < 0)
+		return spi;
+	/* Caller ensures dynptr is valid and initialized, which means spi is in
+	 * bounds and spi is the first dynptr slot. Simply mark stack slot as
+	 * read.
+	 */
+	ret = mark_reg_read(env, &state->stack[spi].spilled_ptr,
+			    state->stack[spi].spilled_ptr.parent, REG_LIVE_READ64);
+	if (ret)
+		return ret;
+	return mark_reg_read(env, &state->stack[spi - 1].spilled_ptr,
+			     state->stack[spi - 1].spilled_ptr.parent, REG_LIVE_READ64);
+}
+
+static int mark_iter_read(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+			  int spi, int nr_slots)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int err, i;
+
+	for (i = 0; i < nr_slots; i++) {
+		struct bpf_reg_state *st = &state->stack[spi - i].spilled_ptr;
+
+		err = mark_reg_read(env, st, st->parent, REG_LIVE_READ64);
+		if (err)
+			return err;
+
+		mark_stack_slot_scratched(env, spi - i);
+	}
+
+	return 0;
+}
+
+/* This function is supposed to be used by the following 32-bit optimization
+ * code only. It returns TRUE if the source or destination register operates
+ * on 64-bit, otherwise return FALSE.
+ */
+static bool is_reg64(struct bpf_verifier_env *env, struct bpf_insn *insn,
+		     u32 regno, struct bpf_reg_state *reg, enum reg_arg_type t)
+{
+	u8 code, class, op;
+
+	code = insn->code;
+	class = BPF_CLASS(code);
+	op = BPF_OP(code);
+	if (class == BPF_JMP) {
+		/* BPF_EXIT for "main" will reach here. Return TRUE
+		 * conservatively.
+		 */
+		if (op == BPF_EXIT)
+			return true;
+		if (op == BPF_CALL) {
+			/* BPF to BPF call will reach here because of marking
+			 * caller saved clobber with DST_OP_NO_MARK for which we
+			 * don't care the register def because they are anyway
+			 * marked as NOT_INIT already.
+			 */
+			if (insn->src_reg == BPF_PSEUDO_CALL)
+				return false;
+			/* Helper call will reach here because of arg type
+			 * check, conservatively return TRUE.
+			 */
+			if (t == SRC_OP)
+				return true;
+
+			return false;
+		}
+	}
+
+	if (class == BPF_ALU64 && op == BPF_END && (insn->imm == 16 || insn->imm == 32))
+		return false;
+
+	if (class == BPF_ALU64 || class == BPF_JMP ||
+	    (class == BPF_ALU && op == BPF_END && insn->imm == 64))
+		return true;
+
+	if (class == BPF_ALU || class == BPF_JMP32)
+		return false;
+
+	if (class == BPF_LDX) {
+		if (t != SRC_OP)
+			return BPF_SIZE(code) == BPF_DW;
+		/* LDX source must be ptr. */
+		return true;
+	}
+
+	if (class == BPF_STX) {
+		/* BPF_STX (including atomic variants) has multiple source
+		 * operands, one of which is a ptr. Check whether the caller is
+		 * asking about it.
+		 */
+		if (t == SRC_OP && reg->type != SCALAR_VALUE)
+			return true;
+		return BPF_SIZE(code) == BPF_DW;
+	}
+
+	if (class == BPF_LD) {
+		u8 mode = BPF_MODE(code);
+
+		/* LD_IMM64 */
+		if (mode == BPF_IMM)
+			return true;
+
+		/* Both LD_IND and LD_ABS return 32-bit data. */
+		if (t != SRC_OP)
+			return  false;
+
+		/* Implicit ctx ptr. */
+		if (regno == BPF_REG_6)
+			return true;
+
+		/* Explicit source could be any width. */
+		return true;
+	}
+
+	if (class == BPF_ST)
+		/* The only source register for BPF_ST is a ptr. */
+		return true;
+
+	/* Conservatively return true at default. */
+	return true;
+}
+
+/* Return the regno defined by the insn, or -1. */
+static int insn_def_regno(const struct bpf_insn *insn)
+{
+	switch (BPF_CLASS(insn->code)) {
+	case BPF_JMP:
+	case BPF_JMP32:
+	case BPF_ST:
+		return -1;
+	case BPF_STX:
+		if (BPF_MODE(insn->code) == BPF_ATOMIC &&
+		    (insn->imm & BPF_FETCH)) {
+			if (insn->imm == BPF_CMPXCHG)
+				return BPF_REG_0;
+			else
+				return insn->src_reg;
+		} else {
+			return -1;
+		}
+	default:
+		return insn->dst_reg;
+	}
+}
+
+/* Return TRUE if INSN has defined any 32-bit value explicitly. */
+static bool insn_has_def32(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	int dst_reg = insn_def_regno(insn);
+
+	if (dst_reg == -1)
+		return false;
+
+	return !is_reg64(env, insn, dst_reg, NULL, DST_OP);
+}
+
+static void mark_insn_zext(struct bpf_verifier_env *env,
+			   struct bpf_reg_state *reg)
+{
+	s32 def_idx = reg->subreg_def;
+
+	if (def_idx == DEF_NOT_SUBREG)
+		return;
+
+	env->insn_aux_data[def_idx - 1].zext_dst = true;
+	/* The dst will be zero extended, so won't be sub-register anymore. */
+	reg->subreg_def = DEF_NOT_SUBREG;
+}
+
+static int __check_reg_arg(struct bpf_verifier_env *env, struct bpf_reg_state *regs, u32 regno,
+			   enum reg_arg_type t)
+{
+	struct bpf_insn *insn = env->prog->insnsi + env->insn_idx;
+	struct bpf_reg_state *reg;
+	bool rw64;
+
+	if (regno >= MAX_BPF_REG) {
+		verbose(env, "R%d is invalid\n", regno);
+		return -EINVAL;
+	}
+
+	mark_reg_scratched(env, regno);
+
+	reg = &regs[regno];
+	rw64 = is_reg64(env, insn, regno, reg, t);
+	if (t == SRC_OP) {
+		/* check whether register used as source operand can be read */
+		if (reg->type == NOT_INIT) {
+			verbose(env, "R%d !read_ok\n", regno);
+			return -EACCES;
+		}
+		/* We don't need to worry about FP liveness because it's read-only */
+		if (regno == BPF_REG_FP)
+			return 0;
+
+		if (rw64)
+			mark_insn_zext(env, reg);
+
+		return mark_reg_read(env, reg, reg->parent,
+				     rw64 ? REG_LIVE_READ64 : REG_LIVE_READ32);
+	} else {
+		/* check whether register used as dest operand can be written to */
+		if (regno == BPF_REG_FP) {
+			verbose(env, "frame pointer is read only\n");
+			return -EACCES;
+		}
+		reg->live |= REG_LIVE_WRITTEN;
+		reg->subreg_def = rw64 ? DEF_NOT_SUBREG : env->insn_idx + 1;
+		if (t == DST_OP)
+			mark_reg_unknown(env, regs, regno);
+	}
+	return 0;
+}
+
+static int check_reg_arg(struct bpf_verifier_env *env, u32 regno,
+			 enum reg_arg_type t)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+
+	return __check_reg_arg(env, state->regs, regno, t);
+}
+
+static void mark_jmp_point(struct bpf_verifier_env *env, int idx)
+{
+	env->insn_aux_data[idx].jmp_point = true;
+}
+
+static bool is_jmp_point(struct bpf_verifier_env *env, int insn_idx)
+{
+	return env->insn_aux_data[insn_idx].jmp_point;
+}
+
+/* for any branch, call, exit record the history of jmps in the given state */
+static int push_jmp_history(struct bpf_verifier_env *env,
+			    struct bpf_verifier_state *cur)
+{
+	u32 cnt = cur->jmp_history_cnt;
+	struct bpf_idx_pair *p;
+	size_t alloc_size;
+
+	if (!is_jmp_point(env, env->insn_idx))
+		return 0;
+
+	cnt++;
+	alloc_size = kmalloc_size_roundup(size_mul(cnt, sizeof(*p)));
+	p = krealloc(cur->jmp_history, alloc_size, GFP_USER);
+	if (!p)
+		return -ENOMEM;
+	p[cnt - 1].idx = env->insn_idx;
+	p[cnt - 1].prev_idx = env->prev_insn_idx;
+	cur->jmp_history = p;
+	cur->jmp_history_cnt = cnt;
+	return 0;
+}
+
+/* Backtrack one insn at a time. If idx is not at the top of recorded
+ * history then previous instruction came from straight line execution.
+ * Return -ENOENT if we exhausted all instructions within given state.
+ *
+ * It's legal to have a bit of a looping with the same starting and ending
+ * insn index within the same state, e.g.: 3->4->5->3, so just because current
+ * instruction index is the same as state's first_idx doesn't mean we are
+ * done. If there is still some jump history left, we should keep going. We
+ * need to take into account that we might have a jump history between given
+ * state's parent and itself, due to checkpointing. In this case, we'll have
+ * history entry recording a jump from last instruction of parent state and
+ * first instruction of given state.
+ */
+static int get_prev_insn_idx(struct bpf_verifier_state *st, int i,
+			     u32 *history)
+{
+	u32 cnt = *history;
+
+	if (i == st->first_insn_idx) {
+		if (cnt == 0)
+			return -ENOENT;
+		if (cnt == 1 && st->jmp_history[0].idx == i)
+			return -ENOENT;
+	}
+
+	if (cnt && st->jmp_history[cnt - 1].idx == i) {
+		i = st->jmp_history[cnt - 1].prev_idx;
+		(*history)--;
+	} else {
+		i--;
+	}
+	return i;
+}
+
+static const char *disasm_kfunc_name(void *data, const struct bpf_insn *insn)
+{
+	const struct btf_type *func;
+	struct btf *desc_btf;
+
+	if (insn->src_reg != BPF_PSEUDO_KFUNC_CALL)
+		return NULL;
+
+	desc_btf = find_kfunc_desc_btf(data, insn->off);
+	if (IS_ERR(desc_btf))
+		return "<error>";
+
+	func = btf_type_by_id(desc_btf, insn->imm);
+	return btf_name_by_offset(desc_btf, func->name_off);
+}
+
+static inline void bt_init(struct backtrack_state *bt, u32 frame)
+{
+	bt->frame = frame;
+}
+
+static inline void bt_reset(struct backtrack_state *bt)
+{
+	struct bpf_verifier_env *env = bt->env;
+
+	memset(bt, 0, sizeof(*bt));
+	bt->env = env;
+}
+
+static inline u32 bt_empty(struct backtrack_state *bt)
+{
+	u64 mask = 0;
+	int i;
+
+	for (i = 0; i <= bt->frame; i++)
+		mask |= bt->reg_masks[i] | bt->stack_masks[i];
+
+	return mask == 0;
+}
+
+static inline int bt_subprog_enter(struct backtrack_state *bt)
+{
+	if (bt->frame == MAX_CALL_FRAMES - 1) {
+		verbose(bt->env, "BUG subprog enter from frame %d\n", bt->frame);
+		WARN_ONCE(1, "verifier backtracking bug");
+		return -EFAULT;
+	}
+	bt->frame++;
+	return 0;
+}
+
+static inline int bt_subprog_exit(struct backtrack_state *bt)
+{
+	if (bt->frame == 0) {
+		verbose(bt->env, "BUG subprog exit from frame 0\n");
+		WARN_ONCE(1, "verifier backtracking bug");
+		return -EFAULT;
+	}
+	bt->frame--;
+	return 0;
+}
+
+static inline void bt_set_frame_reg(struct backtrack_state *bt, u32 frame, u32 reg)
+{
+	bt->reg_masks[frame] |= 1 << reg;
+}
+
+static inline void bt_clear_frame_reg(struct backtrack_state *bt, u32 frame, u32 reg)
+{
+	bt->reg_masks[frame] &= ~(1 << reg);
+}
+
+static inline void bt_set_reg(struct backtrack_state *bt, u32 reg)
+{
+	bt_set_frame_reg(bt, bt->frame, reg);
+}
+
+static inline void bt_clear_reg(struct backtrack_state *bt, u32 reg)
+{
+	bt_clear_frame_reg(bt, bt->frame, reg);
+}
+
+static inline void bt_set_frame_slot(struct backtrack_state *bt, u32 frame, u32 slot)
+{
+	bt->stack_masks[frame] |= 1ull << slot;
+}
+
+static inline void bt_clear_frame_slot(struct backtrack_state *bt, u32 frame, u32 slot)
+{
+	bt->stack_masks[frame] &= ~(1ull << slot);
+}
+
+static inline void bt_set_slot(struct backtrack_state *bt, u32 slot)
+{
+	bt_set_frame_slot(bt, bt->frame, slot);
+}
+
+static inline void bt_clear_slot(struct backtrack_state *bt, u32 slot)
+{
+	bt_clear_frame_slot(bt, bt->frame, slot);
+}
+
+static inline u32 bt_frame_reg_mask(struct backtrack_state *bt, u32 frame)
+{
+	return bt->reg_masks[frame];
+}
+
+static inline u32 bt_reg_mask(struct backtrack_state *bt)
+{
+	return bt->reg_masks[bt->frame];
+}
+
+static inline u64 bt_frame_stack_mask(struct backtrack_state *bt, u32 frame)
+{
+	return bt->stack_masks[frame];
+}
+
+static inline u64 bt_stack_mask(struct backtrack_state *bt)
+{
+	return bt->stack_masks[bt->frame];
+}
+
+static inline bool bt_is_reg_set(struct backtrack_state *bt, u32 reg)
+{
+	return bt->reg_masks[bt->frame] & (1 << reg);
+}
+
+static inline bool bt_is_slot_set(struct backtrack_state *bt, u32 slot)
+{
+	return bt->stack_masks[bt->frame] & (1ull << slot);
+}
+
+/* format registers bitmask, e.g., "r0,r2,r4" for 0x15 mask */
+static void fmt_reg_mask(char *buf, ssize_t buf_sz, u32 reg_mask)
+{
+	DECLARE_BITMAP(mask, 64);
+	bool first = true;
+	int i, n;
+
+	buf[0] = '\0';
+
+	bitmap_from_u64(mask, reg_mask);
+	for_each_set_bit(i, mask, 32) {
+		n = snprintf(buf, buf_sz, "%sr%d", first ? "" : ",", i);
+		first = false;
+		buf += n;
+		buf_sz -= n;
+		if (buf_sz < 0)
+			break;
+	}
+}
+/* format stack slots bitmask, e.g., "-8,-24,-40" for 0x15 mask */
+static void fmt_stack_mask(char *buf, ssize_t buf_sz, u64 stack_mask)
+{
+	DECLARE_BITMAP(mask, 64);
+	bool first = true;
+	int i, n;
+
+	buf[0] = '\0';
+
+	bitmap_from_u64(mask, stack_mask);
+	for_each_set_bit(i, mask, 64) {
+		n = snprintf(buf, buf_sz, "%s%d", first ? "" : ",", -(i + 1) * 8);
+		first = false;
+		buf += n;
+		buf_sz -= n;
+		if (buf_sz < 0)
+			break;
+	}
+}
+
+static bool calls_callback(struct bpf_verifier_env *env, int insn_idx);
+
+/* For given verifier state backtrack_insn() is called from the last insn to
+ * the first insn. Its purpose is to compute a bitmask of registers and
+ * stack slots that needs precision in the parent verifier state.
+ *
+ * @idx is an index of the instruction we are currently processing;
+ * @subseq_idx is an index of the subsequent instruction that:
+ *   - *would be* executed next, if jump history is viewed in forward order;
+ *   - *was* processed previously during backtracking.
+ */
+static int backtrack_insn(struct bpf_verifier_env *env, int idx, int subseq_idx,
+			  struct backtrack_state *bt)
+{
+	const struct bpf_insn_cbs cbs = {
+		.cb_call	= disasm_kfunc_name,
+		.cb_print	= verbose,
+		.private_data	= env,
+	};
+	struct bpf_insn *insn = env->prog->insnsi + idx;
+	u8 class = BPF_CLASS(insn->code);
+	u8 opcode = BPF_OP(insn->code);
+	u8 mode = BPF_MODE(insn->code);
+	u32 dreg = insn->dst_reg;
+	u32 sreg = insn->src_reg;
+	u32 spi, i;
+
+	if (insn->code == 0)
+		return 0;
+	if (env->log.level & BPF_LOG_LEVEL2) {
+		fmt_reg_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, bt_reg_mask(bt));
+		verbose(env, "mark_precise: frame%d: regs=%s ",
+			bt->frame, env->tmp_str_buf);
+		fmt_stack_mask(env->tmp_str_buf, TMP_STR_BUF_LEN, bt_stack_mask(bt));
+		verbose(env, "stack=%s before ", env->tmp_str_buf);
+		verbose(env, "%d: ", idx);
+		print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
+	}
+
+	if (class == BPF_ALU || class == BPF_ALU64) {
+		if (!bt_is_reg_set(bt, dreg))
+			return 0;
+		if (opcode == BPF_END || opcode == BPF_NEG) {
+			/* sreg is reserved and unused
+			 * dreg still need precision before this insn
+			 */
+			return 0;
+		} else if (opcode == BPF_MOV) {
+			if (BPF_SRC(insn->code) == BPF_X) {
+				/* dreg = sreg or dreg = (s8, s16, s32)sreg
+				 * dreg needs precision after this insn
+				 * sreg needs precision before this insn
+				 */
+				bt_clear_reg(bt, dreg);
+				bt_set_reg(bt, sreg);
+			} else {
+				/* dreg = K
+				 * dreg needs precision after this insn.
+				 * Corresponding register is already marked
+				 * as precise=true in this verifier state.
+				 * No further markings in parent are necessary
+				 */
+				bt_clear_reg(bt, dreg);
+			}
+		} else {
+			if (BPF_SRC(insn->code) == BPF_X) {
+				/* dreg += sreg
+				 * both dreg and sreg need precision
+				 * before this insn
+				 */
+				bt_set_reg(bt, sreg);
+			} /* else dreg += K
+			   * dreg still needs precision before this insn
+			   */
+		}
+	} else if (class == BPF_LDX) {
+		if (!bt_is_reg_set(bt, dreg))
+			return 0;
+		bt_clear_reg(bt, dreg);
+
+		/* scalars can only be spilled into stack w/o losing precision.
+		 * Load from any other memory can be zero extended.
+		 * The desire to keep that precision is already indicated
+		 * by 'precise' mark in corresponding register of this state.
+		 * No further tracking necessary.
+		 */
+		if (insn->src_reg != BPF_REG_FP)
+			return 0;
+
+		/* dreg = *(u64 *)[fp - off] was a fill from the stack.
+		 * that [fp - off] slot contains scalar that needs to be
+		 * tracked with precision
+		 */
+		spi = (-insn->off - 1) / BPF_REG_SIZE;
+		if (spi >= 64) {
+			verbose(env, "BUG spi %d\n", spi);
+			WARN_ONCE(1, "verifier backtracking bug");
+			return -EFAULT;
+		}
+		bt_set_slot(bt, spi);
+	} else if (class == BPF_STX || class == BPF_ST) {
+		if (bt_is_reg_set(bt, dreg))
+			/* stx & st shouldn't be using _scalar_ dst_reg
+			 * to access memory. It means backtracking
+			 * encountered a case of pointer subtraction.
+			 */
+			return -ENOTSUPP;
+		/* scalars can only be spilled into stack */
+		if (insn->dst_reg != BPF_REG_FP)
+			return 0;
+		spi = (-insn->off - 1) / BPF_REG_SIZE;
+		if (spi >= 64) {
+			verbose(env, "BUG spi %d\n", spi);
+			WARN_ONCE(1, "verifier backtracking bug");
+			return -EFAULT;
+		}
+		if (!bt_is_slot_set(bt, spi))
+			return 0;
+		bt_clear_slot(bt, spi);
+		if (class == BPF_STX)
+			bt_set_reg(bt, sreg);
+	} else if (class == BPF_JMP || class == BPF_JMP32) {
+		if (bpf_pseudo_call(insn)) {
+			int subprog_insn_idx, subprog;
+
+			subprog_insn_idx = idx + insn->imm + 1;
+			subprog = find_subprog(env, subprog_insn_idx);
+			if (subprog < 0)
+				return -EFAULT;
+
+			if (subprog_is_global(env, subprog)) {
+				/* check that jump history doesn't have any
+				 * extra instructions from subprog; the next
+				 * instruction after call to global subprog
+				 * should be literally next instruction in
+				 * caller program
+				 */
+				WARN_ONCE(idx + 1 != subseq_idx, "verifier backtracking bug");
+				/* r1-r5 are invalidated after subprog call,
+				 * so for global func call it shouldn't be set
+				 * anymore
+				 */
+				if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
+					verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+					WARN_ONCE(1, "verifier backtracking bug");
+					return -EFAULT;
+				}
+				/* global subprog always sets R0 */
+				bt_clear_reg(bt, BPF_REG_0);
+				return 0;
+			} else {
+				/* static subprog call instruction, which
+				 * means that we are exiting current subprog,
+				 * so only r1-r5 could be still requested as
+				 * precise, r0 and r6-r10 or any stack slot in
+				 * the current frame should be zero by now
+				 */
+				if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) {
+					verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+					WARN_ONCE(1, "verifier backtracking bug");
+					return -EFAULT;
+				}
+				/* we don't track register spills perfectly,
+				 * so fallback to force-precise instead of failing */
+				if (bt_stack_mask(bt) != 0)
+					return -ENOTSUPP;
+				/* propagate r1-r5 to the caller */
+				for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
+					if (bt_is_reg_set(bt, i)) {
+						bt_clear_reg(bt, i);
+						bt_set_frame_reg(bt, bt->frame - 1, i);
+					}
+				}
+				if (bt_subprog_exit(bt))
+					return -EFAULT;
+				return 0;
+			}
+		} else if (is_sync_callback_calling_insn(insn) && idx != subseq_idx - 1) {
+			/* exit from callback subprog to callback-calling helper or
+			 * kfunc call. Use idx/subseq_idx check to discern it from
+			 * straight line code backtracking.
+			 * Unlike the subprog call handling above, we shouldn't
+			 * propagate precision of r1-r5 (if any requested), as they are
+			 * not actually arguments passed directly to callback subprogs
+			 */
+			if (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) {
+				verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+				WARN_ONCE(1, "verifier backtracking bug");
+				return -EFAULT;
+			}
+			if (bt_stack_mask(bt) != 0)
+				return -ENOTSUPP;
+			/* clear r1-r5 in callback subprog's mask */
+			for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+				bt_clear_reg(bt, i);
+			if (bt_subprog_exit(bt))
+				return -EFAULT;
+			return 0;
+		} else if (opcode == BPF_CALL) {
+			/* kfunc with imm==0 is invalid and fixup_kfunc_call will
+			 * catch this error later. Make backtracking conservative
+			 * with ENOTSUPP.
+			 */
+			if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL && insn->imm == 0)
+				return -ENOTSUPP;
+			/* regular helper call sets R0 */
+			bt_clear_reg(bt, BPF_REG_0);
+			if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
+				/* if backtracing was looking for registers R1-R5
+				 * they should have been found already.
+				 */
+				verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+				WARN_ONCE(1, "verifier backtracking bug");
+				return -EFAULT;
+			}
+		} else if (opcode == BPF_EXIT) {
+			bool r0_precise;
+
+			/* Backtracking to a nested function call, 'idx' is a part of
+			 * the inner frame 'subseq_idx' is a part of the outer frame.
+			 * In case of a regular function call, instructions giving
+			 * precision to registers R1-R5 should have been found already.
+			 * In case of a callback, it is ok to have R1-R5 marked for
+			 * backtracking, as these registers are set by the function
+			 * invoking callback.
+			 */
+			if (subseq_idx >= 0 && calls_callback(env, subseq_idx))
+				for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+					bt_clear_reg(bt, i);
+			if (bt_reg_mask(bt) & BPF_REGMASK_ARGS) {
+				verbose(env, "BUG regs %x\n", bt_reg_mask(bt));
+				WARN_ONCE(1, "verifier backtracking bug");
+				return -EFAULT;
+			}
+
+			/* BPF_EXIT in subprog or callback always returns
+			 * right after the call instruction, so by checking
+			 * whether the instruction at subseq_idx-1 is subprog
+			 * call or not we can distinguish actual exit from
+			 * *subprog* from exit from *callback*. In the former
+			 * case, we need to propagate r0 precision, if
+			 * necessary. In the former we never do that.
+			 */
+			r0_precise = subseq_idx - 1 >= 0 &&
+				     bpf_pseudo_call(&env->prog->insnsi[subseq_idx - 1]) &&
+				     bt_is_reg_set(bt, BPF_REG_0);
+
+			bt_clear_reg(bt, BPF_REG_0);
+			if (bt_subprog_enter(bt))
+				return -EFAULT;
+
+			if (r0_precise)
+				bt_set_reg(bt, BPF_REG_0);
+			/* r6-r9 and stack slots will stay set in caller frame
+			 * bitmasks until we return back from callee(s)
+			 */
+			return 0;
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			if (!bt_is_reg_set(bt, dreg) && !bt_is_reg_set(bt, sreg))
+				return 0;
+			/* dreg <cond> sreg
+			 * Both dreg and sreg need precision before
+			 * this insn. If only sreg was marked precise
+			 * before it would be equally necessary to
+			 * propagate it to dreg.
+			 */
+			bt_set_reg(bt, dreg);
+			bt_set_reg(bt, sreg);
+			 /* else dreg <cond> K
+			  * Only dreg still needs precision before
+			  * this insn, so for the K-based conditional
+			  * there is nothing new to be marked.
+			  */
+		}
+	} else if (class == BPF_LD) {
+		if (!bt_is_reg_set(bt, dreg))
+			return 0;
+		bt_clear_reg(bt, dreg);
+		/* It's ld_imm64 or ld_abs or ld_ind.
+		 * For ld_imm64 no further tracking of precision
+		 * into parent is necessary
+		 */
+		if (mode == BPF_IND || mode == BPF_ABS)
+			/* to be analyzed */
+			return -ENOTSUPP;
+	}
+	return 0;
+}
+
+/* the scalar precision tracking algorithm:
+ * . at the start all registers have precise=false.
+ * . scalar ranges are tracked as normal through alu and jmp insns.
+ * . once precise value of the scalar register is used in:
+ *   .  ptr + scalar alu
+ *   . if (scalar cond K|scalar)
+ *   .  helper_call(.., scalar, ...) where ARG_CONST is expected
+ *   backtrack through the verifier states and mark all registers and
+ *   stack slots with spilled constants that these scalar regisers
+ *   should be precise.
+ * . during state pruning two registers (or spilled stack slots)
+ *   are equivalent if both are not precise.
+ *
+ * Note the verifier cannot simply walk register parentage chain,
+ * since many different registers and stack slots could have been
+ * used to compute single precise scalar.
+ *
+ * The approach of starting with precise=true for all registers and then
+ * backtrack to mark a register as not precise when the verifier detects
+ * that program doesn't care about specific value (e.g., when helper
+ * takes register as ARG_ANYTHING parameter) is not safe.
+ *
+ * It's ok to walk single parentage chain of the verifier states.
+ * It's possible that this backtracking will go all the way till 1st insn.
+ * All other branches will be explored for needing precision later.
+ *
+ * The backtracking needs to deal with cases like:
+ *   R8=map_value(id=0,off=0,ks=4,vs=1952,imm=0) R9_w=map_value(id=0,off=40,ks=4,vs=1952,imm=0)
+ * r9 -= r8
+ * r5 = r9
+ * if r5 > 0x79f goto pc+7
+ *    R5_w=inv(id=0,umax_value=1951,var_off=(0x0; 0x7ff))
+ * r5 += 1
+ * ...
+ * call bpf_perf_event_output#25
+ *   where .arg5_type = ARG_CONST_SIZE_OR_ZERO
+ *
+ * and this case:
+ * r6 = 1
+ * call foo // uses callee's r6 inside to compute r0
+ * r0 += r6
+ * if r0 == 0 goto
+ *
+ * to track above reg_mask/stack_mask needs to be independent for each frame.
+ *
+ * Also if parent's curframe > frame where backtracking started,
+ * the verifier need to mark registers in both frames, otherwise callees
+ * may incorrectly prune callers. This is similar to
+ * commit 7640ead93924 ("bpf: verifier: make sure callees don't prune with caller differences")
+ *
+ * For now backtracking falls back into conservative marking.
+ */
+static void mark_all_scalars_precise(struct bpf_verifier_env *env,
+				     struct bpf_verifier_state *st)
+{
+	struct bpf_func_state *func;
+	struct bpf_reg_state *reg;
+	int i, j;
+
+	if (env->log.level & BPF_LOG_LEVEL2) {
+		verbose(env, "mark_precise: frame%d: falling back to forcing all scalars precise\n",
+			st->curframe);
+	}
+
+	/* big hammer: mark all scalars precise in this path.
+	 * pop_stack may still get !precise scalars.
+	 * We also skip current state and go straight to first parent state,
+	 * because precision markings in current non-checkpointed state are
+	 * not needed. See why in the comment in __mark_chain_precision below.
+	 */
+	for (st = st->parent; st; st = st->parent) {
+		for (i = 0; i <= st->curframe; i++) {
+			func = st->frame[i];
+			for (j = 0; j < BPF_REG_FP; j++) {
+				reg = &func->regs[j];
+				if (reg->type != SCALAR_VALUE || reg->precise)
+					continue;
+				reg->precise = true;
+				if (env->log.level & BPF_LOG_LEVEL2) {
+					verbose(env, "force_precise: frame%d: forcing r%d to be precise\n",
+						i, j);
+				}
+			}
+			for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
+				if (!is_spilled_reg(&func->stack[j]))
+					continue;
+				reg = &func->stack[j].spilled_ptr;
+				if (reg->type != SCALAR_VALUE || reg->precise)
+					continue;
+				reg->precise = true;
+				if (env->log.level & BPF_LOG_LEVEL2) {
+					verbose(env, "force_precise: frame%d: forcing fp%d to be precise\n",
+						i, -(j + 1) * 8);
+				}
+			}
+		}
+	}
+}
+
+static void mark_all_scalars_imprecise(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+	struct bpf_func_state *func;
+	struct bpf_reg_state *reg;
+	int i, j;
+
+	for (i = 0; i <= st->curframe; i++) {
+		func = st->frame[i];
+		for (j = 0; j < BPF_REG_FP; j++) {
+			reg = &func->regs[j];
+			if (reg->type != SCALAR_VALUE)
+				continue;
+			reg->precise = false;
+		}
+		for (j = 0; j < func->allocated_stack / BPF_REG_SIZE; j++) {
+			if (!is_spilled_reg(&func->stack[j]))
+				continue;
+			reg = &func->stack[j].spilled_ptr;
+			if (reg->type != SCALAR_VALUE)
+				continue;
+			reg->precise = false;
+		}
+	}
+}
+
+static bool idset_contains(struct bpf_idset *s, u32 id)
+{
+	u32 i;
+
+	for (i = 0; i < s->count; ++i)
+		if (s->ids[i] == id)
+			return true;
+
+	return false;
+}
+
+static int idset_push(struct bpf_idset *s, u32 id)
+{
+	if (WARN_ON_ONCE(s->count >= ARRAY_SIZE(s->ids)))
+		return -EFAULT;
+	s->ids[s->count++] = id;
+	return 0;
+}
+
+static void idset_reset(struct bpf_idset *s)
+{
+	s->count = 0;
+}
+
+/* Collect a set of IDs for all registers currently marked as precise in env->bt.
+ * Mark all registers with these IDs as precise.
+ */
+static int mark_precise_scalar_ids(struct bpf_verifier_env *env, struct bpf_verifier_state *st)
+{
+	struct bpf_idset *precise_ids = &env->idset_scratch;
+	struct backtrack_state *bt = &env->bt;
+	struct bpf_func_state *func;
+	struct bpf_reg_state *reg;
+	DECLARE_BITMAP(mask, 64);
+	int i, fr;
+
+	idset_reset(precise_ids);
+
+	for (fr = bt->frame; fr >= 0; fr--) {
+		func = st->frame[fr];
+
+		bitmap_from_u64(mask, bt_frame_reg_mask(bt, fr));
+		for_each_set_bit(i, mask, 32) {
+			reg = &func->regs[i];
+			if (!reg->id || reg->type != SCALAR_VALUE)
+				continue;
+			if (idset_push(precise_ids, reg->id))
+				return -EFAULT;
+		}
+
+		bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr));
+		for_each_set_bit(i, mask, 64) {
+			if (i >= func->allocated_stack / BPF_REG_SIZE)
+				break;
+			if (!is_spilled_scalar_reg(&func->stack[i]))
+				continue;
+			reg = &func->stack[i].spilled_ptr;
+			if (!reg->id)
+				continue;
+			if (idset_push(precise_ids, reg->id))
+				return -EFAULT;
+		}
+	}
+
+	for (fr = 0; fr <= st->curframe; ++fr) {
+		func = st->frame[fr];
+
+		for (i = BPF_REG_0; i < BPF_REG_10; ++i) {
+			reg = &func->regs[i];
+			if (!reg->id)
+				continue;
+			if (!idset_contains(precise_ids, reg->id))
+				continue;
+			bt_set_frame_reg(bt, fr, i);
+		}
+		for (i = 0; i < func->allocated_stack / BPF_REG_SIZE; ++i) {
+			if (!is_spilled_scalar_reg(&func->stack[i]))
+				continue;
+			reg = &func->stack[i].spilled_ptr;
+			if (!reg->id)
+				continue;
+			if (!idset_contains(precise_ids, reg->id))
+				continue;
+			bt_set_frame_slot(bt, fr, i);
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * __mark_chain_precision() backtracks BPF program instruction sequence and
+ * chain of verifier states making sure that register *regno* (if regno >= 0)
+ * and/or stack slot *spi* (if spi >= 0) are marked as precisely tracked
+ * SCALARS, as well as any other registers and slots that contribute to
+ * a tracked state of given registers/stack slots, depending on specific BPF
+ * assembly instructions (see backtrack_insns() for exact instruction handling
+ * logic). This backtracking relies on recorded jmp_history and is able to
+ * traverse entire chain of parent states. This process ends only when all the
+ * necessary registers/slots and their transitive dependencies are marked as
+ * precise.
+ *
+ * One important and subtle aspect is that precise marks *do not matter* in
+ * the currently verified state (current state). It is important to understand
+ * why this is the case.
+ *
+ * First, note that current state is the state that is not yet "checkpointed",
+ * i.e., it is not yet put into env->explored_states, and it has no children
+ * states as well. It's ephemeral, and can end up either a) being discarded if
+ * compatible explored state is found at some point or BPF_EXIT instruction is
+ * reached or b) checkpointed and put into env->explored_states, branching out
+ * into one or more children states.
+ *
+ * In the former case, precise markings in current state are completely
+ * ignored by state comparison code (see regsafe() for details). Only
+ * checkpointed ("old") state precise markings are important, and if old
+ * state's register/slot is precise, regsafe() assumes current state's
+ * register/slot as precise and checks value ranges exactly and precisely. If
+ * states turn out to be compatible, current state's necessary precise
+ * markings and any required parent states' precise markings are enforced
+ * after the fact with propagate_precision() logic, after the fact. But it's
+ * important to realize that in this case, even after marking current state
+ * registers/slots as precise, we immediately discard current state. So what
+ * actually matters is any of the precise markings propagated into current
+ * state's parent states, which are always checkpointed (due to b) case above).
+ * As such, for scenario a) it doesn't matter if current state has precise
+ * markings set or not.
+ *
+ * Now, for the scenario b), checkpointing and forking into child(ren)
+ * state(s). Note that before current state gets to checkpointing step, any
+ * processed instruction always assumes precise SCALAR register/slot
+ * knowledge: if precise value or range is useful to prune jump branch, BPF
+ * verifier takes this opportunity enthusiastically. Similarly, when
+ * register's value is used to calculate offset or memory address, exact
+ * knowledge of SCALAR range is assumed, checked, and enforced. So, similar to
+ * what we mentioned above about state comparison ignoring precise markings
+ * during state comparison, BPF verifier ignores and also assumes precise
+ * markings *at will* during instruction verification process. But as verifier
+ * assumes precision, it also propagates any precision dependencies across
+ * parent states, which are not yet finalized, so can be further restricted
+ * based on new knowledge gained from restrictions enforced by their children
+ * states. This is so that once those parent states are finalized, i.e., when
+ * they have no more active children state, state comparison logic in
+ * is_state_visited() would enforce strict and precise SCALAR ranges, if
+ * required for correctness.
+ *
+ * To build a bit more intuition, note also that once a state is checkpointed,
+ * the path we took to get to that state is not important. This is crucial
+ * property for state pruning. When state is checkpointed and finalized at
+ * some instruction index, it can be correctly and safely used to "short
+ * circuit" any *compatible* state that reaches exactly the same instruction
+ * index. I.e., if we jumped to that instruction from a completely different
+ * code path than original finalized state was derived from, it doesn't
+ * matter, current state can be discarded because from that instruction
+ * forward having a compatible state will ensure we will safely reach the
+ * exit. States describe preconditions for further exploration, but completely
+ * forget the history of how we got here.
+ *
+ * This also means that even if we needed precise SCALAR range to get to
+ * finalized state, but from that point forward *that same* SCALAR register is
+ * never used in a precise context (i.e., it's precise value is not needed for
+ * correctness), it's correct and safe to mark such register as "imprecise"
+ * (i.e., precise marking set to false). This is what we rely on when we do
+ * not set precise marking in current state. If no child state requires
+ * precision for any given SCALAR register, it's safe to dictate that it can
+ * be imprecise. If any child state does require this register to be precise,
+ * we'll mark it precise later retroactively during precise markings
+ * propagation from child state to parent states.
+ *
+ * Skipping precise marking setting in current state is a mild version of
+ * relying on the above observation. But we can utilize this property even
+ * more aggressively by proactively forgetting any precise marking in the
+ * current state (which we inherited from the parent state), right before we
+ * checkpoint it and branch off into new child state. This is done by
+ * mark_all_scalars_imprecise() to hopefully get more permissive and generic
+ * finalized states which help in short circuiting more future states.
+ */
+static int __mark_chain_precision(struct bpf_verifier_env *env, int regno)
+{
+	struct backtrack_state *bt = &env->bt;
+	struct bpf_verifier_state *st = env->cur_state;
+	int first_idx = st->first_insn_idx;
+	int last_idx = env->insn_idx;
+	int subseq_idx = -1;
+	struct bpf_func_state *func;
+	struct bpf_reg_state *reg;
+	bool skip_first = true;
+	int i, fr, err;
+
+	if (!env->bpf_capable)
+		return 0;
+
+	/* set frame number from which we are starting to backtrack */
+	bt_init(bt, env->cur_state->curframe);
+
+	/* Do sanity checks against current state of register and/or stack
+	 * slot, but don't set precise flag in current state, as precision
+	 * tracking in the current state is unnecessary.
+	 */
+	func = st->frame[bt->frame];
+	if (regno >= 0) {
+		reg = &func->regs[regno];
+		if (reg->type != SCALAR_VALUE) {
+			WARN_ONCE(1, "backtracing misuse");
+			return -EFAULT;
+		}
+		bt_set_reg(bt, regno);
+	}
+
+	if (bt_empty(bt))
+		return 0;
+
+	for (;;) {
+		DECLARE_BITMAP(mask, 64);
+		u32 history = st->jmp_history_cnt;
+
+		if (env->log.level & BPF_LOG_LEVEL2) {
+			verbose(env, "mark_precise: frame%d: last_idx %d first_idx %d subseq_idx %d \n",
+				bt->frame, last_idx, first_idx, subseq_idx);
+		}
+
+		/* If some register with scalar ID is marked as precise,
+		 * make sure that all registers sharing this ID are also precise.
+		 * This is needed to estimate effect of find_equal_scalars().
+		 * Do this at the last instruction of each state,
+		 * bpf_reg_state::id fields are valid for these instructions.
+		 *
+		 * Allows to track precision in situation like below:
+		 *
+		 *     r2 = unknown value
+		 *     ...
+		 *   --- state #0 ---
+		 *     ...
+		 *     r1 = r2                 // r1 and r2 now share the same ID
+		 *     ...
+		 *   --- state #1 {r1.id = A, r2.id = A} ---
+		 *     ...
+		 *     if (r2 > 10) goto exit; // find_equal_scalars() assigns range to r1
+		 *     ...
+		 *   --- state #2 {r1.id = A, r2.id = A} ---
+		 *     r3 = r10
+		 *     r3 += r1                // need to mark both r1 and r2
+		 */
+		if (mark_precise_scalar_ids(env, st))
+			return -EFAULT;
+
+		if (last_idx < 0) {
+			/* we are at the entry into subprog, which
+			 * is expected for global funcs, but only if
+			 * requested precise registers are R1-R5
+			 * (which are global func's input arguments)
+			 */
+			if (st->curframe == 0 &&
+			    st->frame[0]->subprogno > 0 &&
+			    st->frame[0]->callsite == BPF_MAIN_FUNC &&
+			    bt_stack_mask(bt) == 0 &&
+			    (bt_reg_mask(bt) & ~BPF_REGMASK_ARGS) == 0) {
+				bitmap_from_u64(mask, bt_reg_mask(bt));
+				for_each_set_bit(i, mask, 32) {
+					reg = &st->frame[0]->regs[i];
+					bt_clear_reg(bt, i);
+					if (reg->type == SCALAR_VALUE)
+						reg->precise = true;
+				}
+				return 0;
+			}
+
+			verbose(env, "BUG backtracking func entry subprog %d reg_mask %x stack_mask %llx\n",
+				st->frame[0]->subprogno, bt_reg_mask(bt), bt_stack_mask(bt));
+			WARN_ONCE(1, "verifier backtracking bug");
+			return -EFAULT;
+		}
+
+		for (i = last_idx;;) {
+			if (skip_first) {
+				err = 0;
+				skip_first = false;
+			} else {
+				err = backtrack_insn(env, i, subseq_idx, bt);
+			}
+			if (err == -ENOTSUPP) {
+				mark_all_scalars_precise(env, env->cur_state);
+				bt_reset(bt);
+				return 0;
+			} else if (err) {
+				return err;
+			}
+			if (bt_empty(bt))
+				/* Found assignment(s) into tracked register in this state.
+				 * Since this state is already marked, just return.
+				 * Nothing to be tracked further in the parent state.
+				 */
+				return 0;
+			subseq_idx = i;
+			i = get_prev_insn_idx(st, i, &history);
+			if (i == -ENOENT)
+				break;
+			if (i >= env->prog->len) {
+				/* This can happen if backtracking reached insn 0
+				 * and there are still reg_mask or stack_mask
+				 * to backtrack.
+				 * It means the backtracking missed the spot where
+				 * particular register was initialized with a constant.
+				 */
+				verbose(env, "BUG backtracking idx %d\n", i);
+				WARN_ONCE(1, "verifier backtracking bug");
+				return -EFAULT;
+			}
+		}
+		st = st->parent;
+		if (!st)
+			break;
+
+		for (fr = bt->frame; fr >= 0; fr--) {
+			func = st->frame[fr];
+			bitmap_from_u64(mask, bt_frame_reg_mask(bt, fr));
+			for_each_set_bit(i, mask, 32) {
+				reg = &func->regs[i];
+				if (reg->type != SCALAR_VALUE) {
+					bt_clear_frame_reg(bt, fr, i);
+					continue;
+				}
+				if (reg->precise)
+					bt_clear_frame_reg(bt, fr, i);
+				else
+					reg->precise = true;
+			}
+
+			bitmap_from_u64(mask, bt_frame_stack_mask(bt, fr));
+			for_each_set_bit(i, mask, 64) {
+				if (i >= func->allocated_stack / BPF_REG_SIZE) {
+					/* the sequence of instructions:
+					 * 2: (bf) r3 = r10
+					 * 3: (7b) *(u64 *)(r3 -8) = r0
+					 * 4: (79) r4 = *(u64 *)(r10 -8)
+					 * doesn't contain jmps. It's backtracked
+					 * as a single block.
+					 * During backtracking insn 3 is not recognized as
+					 * stack access, so at the end of backtracking
+					 * stack slot fp-8 is still marked in stack_mask.
+					 * However the parent state may not have accessed
+					 * fp-8 and it's "unallocated" stack space.
+					 * In such case fallback to conservative.
+					 */
+					mark_all_scalars_precise(env, env->cur_state);
+					bt_reset(bt);
+					return 0;
+				}
+
+				if (!is_spilled_scalar_reg(&func->stack[i])) {
+					bt_clear_frame_slot(bt, fr, i);
+					continue;
+				}
+				reg = &func->stack[i].spilled_ptr;
+				if (reg->precise)
+					bt_clear_frame_slot(bt, fr, i);
+				else
+					reg->precise = true;
+			}
+			if (env->log.level & BPF_LOG_LEVEL2) {
+				fmt_reg_mask(env->tmp_str_buf, TMP_STR_BUF_LEN,
+					     bt_frame_reg_mask(bt, fr));
+				verbose(env, "mark_precise: frame%d: parent state regs=%s ",
+					fr, env->tmp_str_buf);
+				fmt_stack_mask(env->tmp_str_buf, TMP_STR_BUF_LEN,
+					       bt_frame_stack_mask(bt, fr));
+				verbose(env, "stack=%s: ", env->tmp_str_buf);
+				print_verifier_state(env, func, true);
+			}
+		}
+
+		if (bt_empty(bt))
+			return 0;
+
+		subseq_idx = first_idx;
+		last_idx = st->last_insn_idx;
+		first_idx = st->first_insn_idx;
+	}
+
+	/* if we still have requested precise regs or slots, we missed
+	 * something (e.g., stack access through non-r10 register), so
+	 * fallback to marking all precise
+	 */
+	if (!bt_empty(bt)) {
+		mark_all_scalars_precise(env, env->cur_state);
+		bt_reset(bt);
+	}
+
+	return 0;
+}
+
+int mark_chain_precision(struct bpf_verifier_env *env, int regno)
+{
+	return __mark_chain_precision(env, regno);
+}
+
+/* mark_chain_precision_batch() assumes that env->bt is set in the caller to
+ * desired reg and stack masks across all relevant frames
+ */
+static int mark_chain_precision_batch(struct bpf_verifier_env *env)
+{
+	return __mark_chain_precision(env, -1);
+}
+
+static bool is_spillable_regtype(enum bpf_reg_type type)
+{
+	switch (base_type(type)) {
+	case PTR_TO_MAP_VALUE:
+	case PTR_TO_STACK:
+	case PTR_TO_CTX:
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+	case PTR_TO_PACKET_END:
+	case PTR_TO_FLOW_KEYS:
+	case CONST_PTR_TO_MAP:
+	case PTR_TO_SOCKET:
+	case PTR_TO_SOCK_COMMON:
+	case PTR_TO_TCP_SOCK:
+	case PTR_TO_XDP_SOCK:
+	case PTR_TO_BTF_ID:
+	case PTR_TO_BUF:
+	case PTR_TO_MEM:
+	case PTR_TO_FUNC:
+	case PTR_TO_MAP_KEY:
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* Does this register contain a constant zero? */
+static bool register_is_null(struct bpf_reg_state *reg)
+{
+	return reg->type == SCALAR_VALUE && tnum_equals_const(reg->var_off, 0);
+}
+
+static bool register_is_const(struct bpf_reg_state *reg)
+{
+	return reg->type == SCALAR_VALUE && tnum_is_const(reg->var_off);
+}
+
+static bool __is_scalar_unbounded(struct bpf_reg_state *reg)
+{
+	return tnum_is_unknown(reg->var_off) &&
+	       reg->smin_value == S64_MIN && reg->smax_value == S64_MAX &&
+	       reg->umin_value == 0 && reg->umax_value == U64_MAX &&
+	       reg->s32_min_value == S32_MIN && reg->s32_max_value == S32_MAX &&
+	       reg->u32_min_value == 0 && reg->u32_max_value == U32_MAX;
+}
+
+static bool register_is_bounded(struct bpf_reg_state *reg)
+{
+	return reg->type == SCALAR_VALUE && !__is_scalar_unbounded(reg);
+}
+
+static bool __is_pointer_value(bool allow_ptr_leaks,
+			       const struct bpf_reg_state *reg)
+{
+	if (allow_ptr_leaks)
+		return false;
+
+	return reg->type != SCALAR_VALUE;
+}
+
+/* Copy src state preserving dst->parent and dst->live fields */
+static void copy_register_state(struct bpf_reg_state *dst, const struct bpf_reg_state *src)
+{
+	struct bpf_reg_state *parent = dst->parent;
+	enum bpf_reg_liveness live = dst->live;
+
+	*dst = *src;
+	dst->parent = parent;
+	dst->live = live;
+}
+
+static void save_register_state(struct bpf_func_state *state,
+				int spi, struct bpf_reg_state *reg,
+				int size)
+{
+	int i;
+
+	copy_register_state(&state->stack[spi].spilled_ptr, reg);
+	if (size == BPF_REG_SIZE)
+		state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+	for (i = BPF_REG_SIZE; i > BPF_REG_SIZE - size; i--)
+		state->stack[spi].slot_type[i - 1] = STACK_SPILL;
+
+	/* size < 8 bytes spill */
+	for (; i; i--)
+		scrub_spilled_slot(&state->stack[spi].slot_type[i - 1]);
+}
+
+static bool is_bpf_st_mem(struct bpf_insn *insn)
+{
+	return BPF_CLASS(insn->code) == BPF_ST && BPF_MODE(insn->code) == BPF_MEM;
+}
+
+/* check_stack_{read,write}_fixed_off functions track spill/fill of registers,
+ * stack boundary and alignment are checked in check_mem_access()
+ */
+static int check_stack_write_fixed_off(struct bpf_verifier_env *env,
+				       /* stack frame we're writing to */
+				       struct bpf_func_state *state,
+				       int off, int size, int value_regno,
+				       int insn_idx)
+{
+	struct bpf_func_state *cur; /* state of the current function */
+	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE, err;
+	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+	struct bpf_reg_state *reg = NULL;
+	u32 dst_reg = insn->dst_reg;
+
+	/* caller checked that off % size == 0 and -MAX_BPF_STACK <= off < 0,
+	 * so it's aligned access and [off, off + size) are within stack limits
+	 */
+	if (!env->allow_ptr_leaks &&
+	    is_spilled_reg(&state->stack[spi]) &&
+	    size != BPF_REG_SIZE) {
+		verbose(env, "attempt to corrupt spilled pointer on stack\n");
+		return -EACCES;
+	}
+
+	cur = env->cur_state->frame[env->cur_state->curframe];
+	if (value_regno >= 0)
+		reg = &cur->regs[value_regno];
+	if (!env->bypass_spec_v4) {
+		bool sanitize = reg && is_spillable_regtype(reg->type);
+
+		for (i = 0; i < size; i++) {
+			u8 type = state->stack[spi].slot_type[i];
+
+			if (type != STACK_MISC && type != STACK_ZERO) {
+				sanitize = true;
+				break;
+			}
+		}
+
+		if (sanitize)
+			env->insn_aux_data[insn_idx].sanitize_stack_spill = true;
+	}
+
+	err = destroy_if_dynptr_stack_slot(env, state, spi);
+	if (err)
+		return err;
+
+	mark_stack_slot_scratched(env, spi);
+	if (reg && !(off % BPF_REG_SIZE) && register_is_bounded(reg) &&
+	    !register_is_null(reg) && env->bpf_capable) {
+		if (dst_reg != BPF_REG_FP) {
+			/* The backtracking logic can only recognize explicit
+			 * stack slot address like [fp - 8]. Other spill of
+			 * scalar via different register has to be conservative.
+			 * Backtrack from here and mark all registers as precise
+			 * that contributed into 'reg' being a constant.
+			 */
+			err = mark_chain_precision(env, value_regno);
+			if (err)
+				return err;
+		}
+		save_register_state(state, spi, reg, size);
+		/* Break the relation on a narrowing spill. */
+		if (fls64(reg->umax_value) > BITS_PER_BYTE * size)
+			state->stack[spi].spilled_ptr.id = 0;
+	} else if (!reg && !(off % BPF_REG_SIZE) && is_bpf_st_mem(insn) &&
+		   insn->imm != 0 && env->bpf_capable) {
+		struct bpf_reg_state fake_reg = {};
+
+		__mark_reg_known(&fake_reg, insn->imm);
+		fake_reg.type = SCALAR_VALUE;
+		save_register_state(state, spi, &fake_reg, size);
+	} else if (reg && is_spillable_regtype(reg->type)) {
+		/* register containing pointer is being spilled into stack */
+		if (size != BPF_REG_SIZE) {
+			verbose_linfo(env, insn_idx, "; ");
+			verbose(env, "invalid size of register spill\n");
+			return -EACCES;
+		}
+		if (state != cur && reg->type == PTR_TO_STACK) {
+			verbose(env, "cannot spill pointers to stack into stack frame of the caller\n");
+			return -EINVAL;
+		}
+		save_register_state(state, spi, reg, size);
+	} else {
+		u8 type = STACK_MISC;
+
+		/* regular write of data into stack destroys any spilled ptr */
+		state->stack[spi].spilled_ptr.type = NOT_INIT;
+		/* Mark slots as STACK_MISC if they belonged to spilled ptr/dynptr/iter. */
+		if (is_stack_slot_special(&state->stack[spi]))
+			for (i = 0; i < BPF_REG_SIZE; i++)
+				scrub_spilled_slot(&state->stack[spi].slot_type[i]);
+
+		/* only mark the slot as written if all 8 bytes were written
+		 * otherwise read propagation may incorrectly stop too soon
+		 * when stack slots are partially written.
+		 * This heuristic means that read propagation will be
+		 * conservative, since it will add reg_live_read marks
+		 * to stack slots all the way to first state when programs
+		 * writes+reads less than 8 bytes
+		 */
+		if (size == BPF_REG_SIZE)
+			state->stack[spi].spilled_ptr.live |= REG_LIVE_WRITTEN;
+
+		/* when we zero initialize stack slots mark them as such */
+		if ((reg && register_is_null(reg)) ||
+		    (!reg && is_bpf_st_mem(insn) && insn->imm == 0)) {
+			/* backtracking doesn't work for STACK_ZERO yet. */
+			err = mark_chain_precision(env, value_regno);
+			if (err)
+				return err;
+			type = STACK_ZERO;
+		}
+
+		/* Mark slots affected by this stack write. */
+		for (i = 0; i < size; i++)
+			state->stack[spi].slot_type[(slot - i) % BPF_REG_SIZE] =
+				type;
+	}
+	return 0;
+}
+
+/* Write the stack: 'stack[ptr_regno + off] = value_regno'. 'ptr_regno' is
+ * known to contain a variable offset.
+ * This function checks whether the write is permitted and conservatively
+ * tracks the effects of the write, considering that each stack slot in the
+ * dynamic range is potentially written to.
+ *
+ * 'off' includes 'regno->off'.
+ * 'value_regno' can be -1, meaning that an unknown value is being written to
+ * the stack.
+ *
+ * Spilled pointers in range are not marked as written because we don't know
+ * what's going to be actually written. This means that read propagation for
+ * future reads cannot be terminated by this write.
+ *
+ * For privileged programs, uninitialized stack slots are considered
+ * initialized by this write (even though we don't know exactly what offsets
+ * are going to be written to). The idea is that we don't want the verifier to
+ * reject future reads that access slots written to through variable offsets.
+ */
+static int check_stack_write_var_off(struct bpf_verifier_env *env,
+				     /* func where register points to */
+				     struct bpf_func_state *state,
+				     int ptr_regno, int off, int size,
+				     int value_regno, int insn_idx)
+{
+	struct bpf_func_state *cur; /* state of the current function */
+	int min_off, max_off;
+	int i, err;
+	struct bpf_reg_state *ptr_reg = NULL, *value_reg = NULL;
+	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+	bool writing_zero = false;
+	/* set if the fact that we're writing a zero is used to let any
+	 * stack slots remain STACK_ZERO
+	 */
+	bool zero_used = false;
+
+	cur = env->cur_state->frame[env->cur_state->curframe];
+	ptr_reg = &cur->regs[ptr_regno];
+	min_off = ptr_reg->smin_value + off;
+	max_off = ptr_reg->smax_value + off + size;
+	if (value_regno >= 0)
+		value_reg = &cur->regs[value_regno];
+	if ((value_reg && register_is_null(value_reg)) ||
+	    (!value_reg && is_bpf_st_mem(insn) && insn->imm == 0))
+		writing_zero = true;
+
+	for (i = min_off; i < max_off; i++) {
+		int spi;
+
+		spi = __get_spi(i);
+		err = destroy_if_dynptr_stack_slot(env, state, spi);
+		if (err)
+			return err;
+	}
+
+	/* Variable offset writes destroy any spilled pointers in range. */
+	for (i = min_off; i < max_off; i++) {
+		u8 new_type, *stype;
+		int slot, spi;
+
+		slot = -i - 1;
+		spi = slot / BPF_REG_SIZE;
+		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
+		mark_stack_slot_scratched(env, spi);
+
+		if (!env->allow_ptr_leaks && *stype != STACK_MISC && *stype != STACK_ZERO) {
+			/* Reject the write if range we may write to has not
+			 * been initialized beforehand. If we didn't reject
+			 * here, the ptr status would be erased below (even
+			 * though not all slots are actually overwritten),
+			 * possibly opening the door to leaks.
+			 *
+			 * We do however catch STACK_INVALID case below, and
+			 * only allow reading possibly uninitialized memory
+			 * later for CAP_PERFMON, as the write may not happen to
+			 * that slot.
+			 */
+			verbose(env, "spilled ptr in range of var-offset stack write; insn %d, ptr off: %d",
+				insn_idx, i);
+			return -EINVAL;
+		}
+
+		/* Erase all spilled pointers. */
+		state->stack[spi].spilled_ptr.type = NOT_INIT;
+
+		/* Update the slot type. */
+		new_type = STACK_MISC;
+		if (writing_zero && *stype == STACK_ZERO) {
+			new_type = STACK_ZERO;
+			zero_used = true;
+		}
+		/* If the slot is STACK_INVALID, we check whether it's OK to
+		 * pretend that it will be initialized by this write. The slot
+		 * might not actually be written to, and so if we mark it as
+		 * initialized future reads might leak uninitialized memory.
+		 * For privileged programs, we will accept such reads to slots
+		 * that may or may not be written because, if we're reject
+		 * them, the error would be too confusing.
+		 */
+		if (*stype == STACK_INVALID && !env->allow_uninit_stack) {
+			verbose(env, "uninit stack in range of var-offset write prohibited for !root; insn %d, off: %d",
+					insn_idx, i);
+			return -EINVAL;
+		}
+		*stype = new_type;
+	}
+	if (zero_used) {
+		/* backtracking doesn't work for STACK_ZERO yet. */
+		err = mark_chain_precision(env, value_regno);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+/* When register 'dst_regno' is assigned some values from stack[min_off,
+ * max_off), we set the register's type according to the types of the
+ * respective stack slots. If all the stack values are known to be zeros, then
+ * so is the destination reg. Otherwise, the register is considered to be
+ * SCALAR. This function does not deal with register filling; the caller must
+ * ensure that all spilled registers in the stack range have been marked as
+ * read.
+ */
+static void mark_reg_stack_read(struct bpf_verifier_env *env,
+				/* func where src register points to */
+				struct bpf_func_state *ptr_state,
+				int min_off, int max_off, int dst_regno)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	int i, slot, spi;
+	u8 *stype;
+	int zeros = 0;
+
+	for (i = min_off; i < max_off; i++) {
+		slot = -i - 1;
+		spi = slot / BPF_REG_SIZE;
+		mark_stack_slot_scratched(env, spi);
+		stype = ptr_state->stack[spi].slot_type;
+		if (stype[slot % BPF_REG_SIZE] != STACK_ZERO)
+			break;
+		zeros++;
+	}
+	if (zeros == max_off - min_off) {
+		/* any access_size read into register is zero extended,
+		 * so the whole register == const_zero
+		 */
+		__mark_reg_const_zero(&state->regs[dst_regno]);
+		/* backtracking doesn't support STACK_ZERO yet,
+		 * so mark it precise here, so that later
+		 * backtracking can stop here.
+		 * Backtracking may not need this if this register
+		 * doesn't participate in pointer adjustment.
+		 * Forward propagation of precise flag is not
+		 * necessary either. This mark is only to stop
+		 * backtracking. Any register that contributed
+		 * to const 0 was marked precise before spill.
+		 */
+		state->regs[dst_regno].precise = true;
+	} else {
+		/* have read misc data from the stack */
+		mark_reg_unknown(env, state->regs, dst_regno);
+	}
+	state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+}
+
+/* Read the stack at 'off' and put the results into the register indicated by
+ * 'dst_regno'. It handles reg filling if the addressed stack slot is a
+ * spilled reg.
+ *
+ * 'dst_regno' can be -1, meaning that the read value is not going to a
+ * register.
+ *
+ * The access is assumed to be within the current stack bounds.
+ */
+static int check_stack_read_fixed_off(struct bpf_verifier_env *env,
+				      /* func where src register points to */
+				      struct bpf_func_state *reg_state,
+				      int off, int size, int dst_regno)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	int i, slot = -off - 1, spi = slot / BPF_REG_SIZE;
+	struct bpf_reg_state *reg;
+	u8 *stype, type;
+
+	stype = reg_state->stack[spi].slot_type;
+	reg = &reg_state->stack[spi].spilled_ptr;
+
+	mark_stack_slot_scratched(env, spi);
+
+	if (is_spilled_reg(&reg_state->stack[spi])) {
+		u8 spill_size = 1;
+
+		for (i = BPF_REG_SIZE - 1; i > 0 && stype[i - 1] == STACK_SPILL; i--)
+			spill_size++;
+
+		if (size != BPF_REG_SIZE || spill_size != BPF_REG_SIZE) {
+			if (reg->type != SCALAR_VALUE) {
+				verbose_linfo(env, env->insn_idx, "; ");
+				verbose(env, "invalid size of register fill\n");
+				return -EACCES;
+			}
+
+			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+			if (dst_regno < 0)
+				return 0;
+
+			if (!(off % BPF_REG_SIZE) && size == spill_size) {
+				/* The earlier check_reg_arg() has decided the
+				 * subreg_def for this insn.  Save it first.
+				 */
+				s32 subreg_def = state->regs[dst_regno].subreg_def;
+
+				copy_register_state(&state->regs[dst_regno], reg);
+				state->regs[dst_regno].subreg_def = subreg_def;
+			} else {
+				for (i = 0; i < size; i++) {
+					type = stype[(slot - i) % BPF_REG_SIZE];
+					if (type == STACK_SPILL)
+						continue;
+					if (type == STACK_MISC)
+						continue;
+					if (type == STACK_INVALID && env->allow_uninit_stack)
+						continue;
+					verbose(env, "invalid read from stack off %d+%d size %d\n",
+						off, i, size);
+					return -EACCES;
+				}
+				mark_reg_unknown(env, state->regs, dst_regno);
+			}
+			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+			return 0;
+		}
+
+		if (dst_regno >= 0) {
+			/* restore register state from stack */
+			copy_register_state(&state->regs[dst_regno], reg);
+			/* mark reg as written since spilled pointer state likely
+			 * has its liveness marks cleared by is_state_visited()
+			 * which resets stack/reg liveness for state transitions
+			 */
+			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
+		} else if (__is_pointer_value(env->allow_ptr_leaks, reg)) {
+			/* If dst_regno==-1, the caller is asking us whether
+			 * it is acceptable to use this value as a SCALAR_VALUE
+			 * (e.g. for XADD).
+			 * We must not allow unprivileged callers to do that
+			 * with spilled pointers.
+			 */
+			verbose(env, "leaking pointer from stack off %d\n",
+				off);
+			return -EACCES;
+		}
+		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+	} else {
+		for (i = 0; i < size; i++) {
+			type = stype[(slot - i) % BPF_REG_SIZE];
+			if (type == STACK_MISC)
+				continue;
+			if (type == STACK_ZERO)
+				continue;
+			if (type == STACK_INVALID && env->allow_uninit_stack)
+				continue;
+			verbose(env, "invalid read from stack off %d+%d size %d\n",
+				off, i, size);
+			return -EACCES;
+		}
+		mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+		if (dst_regno >= 0)
+			mark_reg_stack_read(env, reg_state, off, off + size, dst_regno);
+	}
+	return 0;
+}
+
+enum bpf_access_src {
+	ACCESS_DIRECT = 1,  /* the access is performed by an instruction */
+	ACCESS_HELPER = 2,  /* the access is performed by a helper */
+};
+
+static int check_stack_range_initialized(struct bpf_verifier_env *env,
+					 int regno, int off, int access_size,
+					 bool zero_size_allowed,
+					 enum bpf_access_src type,
+					 struct bpf_call_arg_meta *meta);
+
+static struct bpf_reg_state *reg_state(struct bpf_verifier_env *env, int regno)
+{
+	return cur_regs(env) + regno;
+}
+
+/* Read the stack at 'ptr_regno + off' and put the result into the register
+ * 'dst_regno'.
+ * 'off' includes the pointer register's fixed offset(i.e. 'ptr_regno.off'),
+ * but not its variable offset.
+ * 'size' is assumed to be <= reg size and the access is assumed to be aligned.
+ *
+ * As opposed to check_stack_read_fixed_off, this function doesn't deal with
+ * filling registers (i.e. reads of spilled register cannot be detected when
+ * the offset is not fixed). We conservatively mark 'dst_regno' as containing
+ * SCALAR_VALUE. That's why we assert that the 'ptr_regno' has a variable
+ * offset; for a fixed offset check_stack_read_fixed_off should be used
+ * instead.
+ */
+static int check_stack_read_var_off(struct bpf_verifier_env *env,
+				    int ptr_regno, int off, int size, int dst_regno)
+{
+	/* The state of the source register. */
+	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+	struct bpf_func_state *ptr_state = func(env, reg);
+	int err;
+	int min_off, max_off;
+
+	/* Note that we pass a NULL meta, so raw access will not be permitted.
+	 */
+	err = check_stack_range_initialized(env, ptr_regno, off, size,
+					    false, ACCESS_DIRECT, NULL);
+	if (err)
+		return err;
+
+	min_off = reg->smin_value + off;
+	max_off = reg->smax_value + off;
+	mark_reg_stack_read(env, ptr_state, min_off, max_off + size, dst_regno);
+	return 0;
+}
+
+/* check_stack_read dispatches to check_stack_read_fixed_off or
+ * check_stack_read_var_off.
+ *
+ * The caller must ensure that the offset falls within the allocated stack
+ * bounds.
+ *
+ * 'dst_regno' is a register which will receive the value from the stack. It
+ * can be -1, meaning that the read value is not going to a register.
+ */
+static int check_stack_read(struct bpf_verifier_env *env,
+			    int ptr_regno, int off, int size,
+			    int dst_regno)
+{
+	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+	struct bpf_func_state *state = func(env, reg);
+	int err;
+	/* Some accesses are only permitted with a static offset. */
+	bool var_off = !tnum_is_const(reg->var_off);
+
+	/* The offset is required to be static when reads don't go to a
+	 * register, in order to not leak pointers (see
+	 * check_stack_read_fixed_off).
+	 */
+	if (dst_regno < 0 && var_off) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "variable offset stack pointer cannot be passed into helper function; var_off=%s off=%d size=%d\n",
+			tn_buf, off, size);
+		return -EACCES;
+	}
+	/* Variable offset is prohibited for unprivileged mode for simplicity
+	 * since it requires corresponding support in Spectre masking for stack
+	 * ALU. See also retrieve_ptr_limit(). The check in
+	 * check_stack_access_for_ptr_arithmetic() called by
+	 * adjust_ptr_min_max_vals() prevents users from creating stack pointers
+	 * with variable offsets, therefore no check is required here. Further,
+	 * just checking it here would be insufficient as speculative stack
+	 * writes could still lead to unsafe speculative behaviour.
+	 */
+	if (!var_off) {
+		off += reg->var_off.value;
+		err = check_stack_read_fixed_off(env, state, off, size,
+						 dst_regno);
+	} else {
+		/* Variable offset stack reads need more conservative handling
+		 * than fixed offset ones. Note that dst_regno >= 0 on this
+		 * branch.
+		 */
+		err = check_stack_read_var_off(env, ptr_regno, off, size,
+					       dst_regno);
+	}
+	return err;
+}
+
+
+/* check_stack_write dispatches to check_stack_write_fixed_off or
+ * check_stack_write_var_off.
+ *
+ * 'ptr_regno' is the register used as a pointer into the stack.
+ * 'off' includes 'ptr_regno->off', but not its variable offset (if any).
+ * 'value_regno' is the register whose value we're writing to the stack. It can
+ * be -1, meaning that we're not writing from a register.
+ *
+ * The caller must ensure that the offset falls within the maximum stack size.
+ */
+static int check_stack_write(struct bpf_verifier_env *env,
+			     int ptr_regno, int off, int size,
+			     int value_regno, int insn_idx)
+{
+	struct bpf_reg_state *reg = reg_state(env, ptr_regno);
+	struct bpf_func_state *state = func(env, reg);
+	int err;
+
+	if (tnum_is_const(reg->var_off)) {
+		off += reg->var_off.value;
+		err = check_stack_write_fixed_off(env, state, off, size,
+						  value_regno, insn_idx);
+	} else {
+		/* Variable offset stack reads need more conservative handling
+		 * than fixed offset ones.
+		 */
+		err = check_stack_write_var_off(env, state,
+						ptr_regno, off, size,
+						value_regno, insn_idx);
+	}
+	return err;
+}
+
+static int check_map_access_type(struct bpf_verifier_env *env, u32 regno,
+				 int off, int size, enum bpf_access_type type)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_map *map = regs[regno].map_ptr;
+	u32 cap = bpf_map_flags_to_cap(map);
+
+	if (type == BPF_WRITE && !(cap & BPF_MAP_CAN_WRITE)) {
+		verbose(env, "write into map forbidden, value_size=%d off=%d size=%d\n",
+			map->value_size, off, size);
+		return -EACCES;
+	}
+
+	if (type == BPF_READ && !(cap & BPF_MAP_CAN_READ)) {
+		verbose(env, "read from map forbidden, value_size=%d off=%d size=%d\n",
+			map->value_size, off, size);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+/* check read/write into memory region (e.g., map value, ringbuf sample, etc) */
+static int __check_mem_access(struct bpf_verifier_env *env, int regno,
+			      int off, int size, u32 mem_size,
+			      bool zero_size_allowed)
+{
+	bool size_ok = size > 0 || (size == 0 && zero_size_allowed);
+	struct bpf_reg_state *reg;
+
+	if (off >= 0 && size_ok && (u64)off + size <= mem_size)
+		return 0;
+
+	reg = &cur_regs(env)[regno];
+	switch (reg->type) {
+	case PTR_TO_MAP_KEY:
+		verbose(env, "invalid access to map key, key_size=%d off=%d size=%d\n",
+			mem_size, off, size);
+		break;
+	case PTR_TO_MAP_VALUE:
+		verbose(env, "invalid access to map value, value_size=%d off=%d size=%d\n",
+			mem_size, off, size);
+		break;
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+	case PTR_TO_PACKET_END:
+		verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
+			off, size, regno, reg->id, off, mem_size);
+		break;
+	case PTR_TO_MEM:
+	default:
+		verbose(env, "invalid access to memory, mem_size=%u off=%d size=%d\n",
+			mem_size, off, size);
+	}
+
+	return -EACCES;
+}
+
+/* check read/write into a memory region with possible variable offset */
+static int check_mem_region_access(struct bpf_verifier_env *env, u32 regno,
+				   int off, int size, u32 mem_size,
+				   bool zero_size_allowed)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *reg = &state->regs[regno];
+	int err;
+
+	/* We may have adjusted the register pointing to memory region, so we
+	 * need to try adding each of min_value and max_value to off
+	 * to make sure our theoretical access will be safe.
+	 *
+	 * The minimum value is only important with signed
+	 * comparisons where we can't assume the floor of a
+	 * value is 0.  If we are using signed variables for our
+	 * index'es we need to make sure that whatever we use
+	 * will have a set floor within our range.
+	 */
+	if (reg->smin_value < 0 &&
+	    (reg->smin_value == S64_MIN ||
+	     (off + reg->smin_value != (s64)(s32)(off + reg->smin_value)) ||
+	      reg->smin_value + off < 0)) {
+		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+			regno);
+		return -EACCES;
+	}
+	err = __check_mem_access(env, regno, reg->smin_value + off, size,
+				 mem_size, zero_size_allowed);
+	if (err) {
+		verbose(env, "R%d min value is outside of the allowed memory range\n",
+			regno);
+		return err;
+	}
+
+	/* If we haven't set a max value then we need to bail since we can't be
+	 * sure we won't do bad things.
+	 * If reg->umax_value + off could overflow, treat that as unbounded too.
+	 */
+	if (reg->umax_value >= BPF_MAX_VAR_OFF) {
+		verbose(env, "R%d unbounded memory access, make sure to bounds check any such access\n",
+			regno);
+		return -EACCES;
+	}
+	err = __check_mem_access(env, regno, reg->umax_value + off, size,
+				 mem_size, zero_size_allowed);
+	if (err) {
+		verbose(env, "R%d max value is outside of the allowed memory range\n",
+			regno);
+		return err;
+	}
+
+	return 0;
+}
+
+static int __check_ptr_off_reg(struct bpf_verifier_env *env,
+			       const struct bpf_reg_state *reg, int regno,
+			       bool fixed_off_ok)
+{
+	/* Access to this pointer-typed register or passing it to a helper
+	 * is only allowed in its original, unmodified form.
+	 */
+
+	if (reg->off < 0) {
+		verbose(env, "negative offset %s ptr R%d off=%d disallowed\n",
+			reg_type_str(env, reg->type), regno, reg->off);
+		return -EACCES;
+	}
+
+	if (!fixed_off_ok && reg->off) {
+		verbose(env, "dereference of modified %s ptr R%d off=%d disallowed\n",
+			reg_type_str(env, reg->type), regno, reg->off);
+		return -EACCES;
+	}
+
+	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "variable %s access var_off=%s disallowed\n",
+			reg_type_str(env, reg->type), tn_buf);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+int check_ptr_off_reg(struct bpf_verifier_env *env,
+		      const struct bpf_reg_state *reg, int regno)
+{
+	return __check_ptr_off_reg(env, reg, regno, false);
+}
+
+static int map_kptr_match_type(struct bpf_verifier_env *env,
+			       struct btf_field *kptr_field,
+			       struct bpf_reg_state *reg, u32 regno)
+{
+	const char *targ_name = btf_type_name(kptr_field->kptr.btf, kptr_field->kptr.btf_id);
+	int perm_flags;
+	const char *reg_name = "";
+
+	if (btf_is_kernel(reg->btf)) {
+		perm_flags = PTR_MAYBE_NULL | PTR_TRUSTED | MEM_RCU;
+
+		/* Only unreferenced case accepts untrusted pointers */
+		if (kptr_field->type == BPF_KPTR_UNREF)
+			perm_flags |= PTR_UNTRUSTED;
+	} else {
+		perm_flags = PTR_MAYBE_NULL | MEM_ALLOC;
+	}
+
+	if (base_type(reg->type) != PTR_TO_BTF_ID || (type_flag(reg->type) & ~perm_flags))
+		goto bad_type;
+
+	/* We need to verify reg->type and reg->btf, before accessing reg->btf */
+	reg_name = btf_type_name(reg->btf, reg->btf_id);
+
+	/* For ref_ptr case, release function check should ensure we get one
+	 * referenced PTR_TO_BTF_ID, and that its fixed offset is 0. For the
+	 * normal store of unreferenced kptr, we must ensure var_off is zero.
+	 * Since ref_ptr cannot be accessed directly by BPF insns, checks for
+	 * reg->off and reg->ref_obj_id are not needed here.
+	 */
+	if (__check_ptr_off_reg(env, reg, regno, true))
+		return -EACCES;
+
+	/* A full type match is needed, as BTF can be vmlinux, module or prog BTF, and
+	 * we also need to take into account the reg->off.
+	 *
+	 * We want to support cases like:
+	 *
+	 * struct foo {
+	 *         struct bar br;
+	 *         struct baz bz;
+	 * };
+	 *
+	 * struct foo *v;
+	 * v = func();	      // PTR_TO_BTF_ID
+	 * val->foo = v;      // reg->off is zero, btf and btf_id match type
+	 * val->bar = &v->br; // reg->off is still zero, but we need to retry with
+	 *                    // first member type of struct after comparison fails
+	 * val->baz = &v->bz; // reg->off is non-zero, so struct needs to be walked
+	 *                    // to match type
+	 *
+	 * In the kptr_ref case, check_func_arg_reg_off already ensures reg->off
+	 * is zero. We must also ensure that btf_struct_ids_match does not walk
+	 * the struct to match type against first member of struct, i.e. reject
+	 * second case from above. Hence, when type is BPF_KPTR_REF, we set
+	 * strict mode to true for type match.
+	 */
+	if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+				  kptr_field->kptr.btf, kptr_field->kptr.btf_id,
+				  kptr_field->type == BPF_KPTR_REF))
+		goto bad_type;
+	return 0;
+bad_type:
+	verbose(env, "invalid kptr access, R%d type=%s%s ", regno,
+		reg_type_str(env, reg->type), reg_name);
+	verbose(env, "expected=%s%s", reg_type_str(env, PTR_TO_BTF_ID), targ_name);
+	if (kptr_field->type == BPF_KPTR_UNREF)
+		verbose(env, " or %s%s\n", reg_type_str(env, PTR_TO_BTF_ID | PTR_UNTRUSTED),
+			targ_name);
+	else
+		verbose(env, "\n");
+	return -EINVAL;
+}
+
+/* The non-sleepable programs and sleepable programs with explicit bpf_rcu_read_lock()
+ * can dereference RCU protected pointers and result is PTR_TRUSTED.
+ */
+static bool in_rcu_cs(struct bpf_verifier_env *env)
+{
+	return env->cur_state->active_rcu_lock ||
+	       env->cur_state->active_lock.ptr ||
+	       !env->prog->aux->sleepable;
+}
+
+/* Once GCC supports btf_type_tag the following mechanism will be replaced with tag check */
+BTF_SET_START(rcu_protected_types)
+BTF_ID(struct, prog_test_ref_kfunc)
+BTF_ID(struct, cgroup)
+BTF_ID(struct, bpf_cpumask)
+BTF_ID(struct, task_struct)
+BTF_SET_END(rcu_protected_types)
+
+static bool rcu_protected_object(const struct btf *btf, u32 btf_id)
+{
+	if (!btf_is_kernel(btf))
+		return false;
+	return btf_id_set_contains(&rcu_protected_types, btf_id);
+}
+
+static bool rcu_safe_kptr(const struct btf_field *field)
+{
+	const struct btf_field_kptr *kptr = &field->kptr;
+
+	return field->type == BPF_KPTR_REF && rcu_protected_object(kptr->btf, kptr->btf_id);
+}
+
+static int check_map_kptr_access(struct bpf_verifier_env *env, u32 regno,
+				 int value_regno, int insn_idx,
+				 struct btf_field *kptr_field)
+{
+	struct bpf_insn *insn = &env->prog->insnsi[insn_idx];
+	int class = BPF_CLASS(insn->code);
+	struct bpf_reg_state *val_reg;
+
+	/* Things we already checked for in check_map_access and caller:
+	 *  - Reject cases where variable offset may touch kptr
+	 *  - size of access (must be BPF_DW)
+	 *  - tnum_is_const(reg->var_off)
+	 *  - kptr_field->offset == off + reg->var_off.value
+	 */
+	/* Only BPF_[LDX,STX,ST] | BPF_MEM | BPF_DW is supported */
+	if (BPF_MODE(insn->code) != BPF_MEM) {
+		verbose(env, "kptr in map can only be accessed using BPF_MEM instruction mode\n");
+		return -EACCES;
+	}
+
+	/* We only allow loading referenced kptr, since it will be marked as
+	 * untrusted, similar to unreferenced kptr.
+	 */
+	if (class != BPF_LDX && kptr_field->type == BPF_KPTR_REF) {
+		verbose(env, "store to referenced kptr disallowed\n");
+		return -EACCES;
+	}
+
+	if (class == BPF_LDX) {
+		val_reg = reg_state(env, value_regno);
+		/* We can simply mark the value_regno receiving the pointer
+		 * value from map as PTR_TO_BTF_ID, with the correct type.
+		 */
+		mark_btf_ld_reg(env, cur_regs(env), value_regno, PTR_TO_BTF_ID, kptr_field->kptr.btf,
+				kptr_field->kptr.btf_id,
+				rcu_safe_kptr(kptr_field) && in_rcu_cs(env) ?
+				PTR_MAYBE_NULL | MEM_RCU :
+				PTR_MAYBE_NULL | PTR_UNTRUSTED);
+		/* For mark_ptr_or_null_reg */
+		val_reg->id = ++env->id_gen;
+	} else if (class == BPF_STX) {
+		val_reg = reg_state(env, value_regno);
+		if (!register_is_null(val_reg) &&
+		    map_kptr_match_type(env, kptr_field, val_reg, value_regno))
+			return -EACCES;
+	} else if (class == BPF_ST) {
+		if (insn->imm) {
+			verbose(env, "BPF_ST imm must be 0 when storing to kptr at off=%u\n",
+				kptr_field->offset);
+			return -EACCES;
+		}
+	} else {
+		verbose(env, "kptr in map can only be accessed using BPF_LDX/BPF_STX/BPF_ST\n");
+		return -EACCES;
+	}
+	return 0;
+}
+
+/* check read/write into a map element with possible variable offset */
+static int check_map_access(struct bpf_verifier_env *env, u32 regno,
+			    int off, int size, bool zero_size_allowed,
+			    enum bpf_access_src src)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *reg = &state->regs[regno];
+	struct bpf_map *map = reg->map_ptr;
+	struct btf_record *rec;
+	int err, i;
+
+	err = check_mem_region_access(env, regno, off, size, map->value_size,
+				      zero_size_allowed);
+	if (err)
+		return err;
+
+	if (IS_ERR_OR_NULL(map->record))
+		return 0;
+	rec = map->record;
+	for (i = 0; i < rec->cnt; i++) {
+		struct btf_field *field = &rec->fields[i];
+		u32 p = field->offset;
+
+		/* If any part of a field  can be touched by load/store, reject
+		 * this program. To check that [x1, x2) overlaps with [y1, y2),
+		 * it is sufficient to check x1 < y2 && y1 < x2.
+		 */
+		if (reg->smin_value + off < p + btf_field_type_size(field->type) &&
+		    p < reg->umax_value + off + size) {
+			switch (field->type) {
+			case BPF_KPTR_UNREF:
+			case BPF_KPTR_REF:
+				if (src != ACCESS_DIRECT) {
+					verbose(env, "kptr cannot be accessed indirectly by helper\n");
+					return -EACCES;
+				}
+				if (!tnum_is_const(reg->var_off)) {
+					verbose(env, "kptr access cannot have variable offset\n");
+					return -EACCES;
+				}
+				if (p != off + reg->var_off.value) {
+					verbose(env, "kptr access misaligned expected=%u off=%llu\n",
+						p, off + reg->var_off.value);
+					return -EACCES;
+				}
+				if (size != bpf_size_to_bytes(BPF_DW)) {
+					verbose(env, "kptr access size must be BPF_DW\n");
+					return -EACCES;
+				}
+				break;
+			default:
+				verbose(env, "%s cannot be accessed directly by load/store\n",
+					btf_field_type_name(field->type));
+				return -EACCES;
+			}
+		}
+	}
+	return 0;
+}
+
+#define MAX_PACKET_OFF 0xffff
+
+static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
+				       const struct bpf_call_arg_meta *meta,
+				       enum bpf_access_type t)
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+
+	switch (prog_type) {
+	/* Program types only with direct read access go here! */
+	case BPF_PROG_TYPE_LWT_IN:
+	case BPF_PROG_TYPE_LWT_OUT:
+	case BPF_PROG_TYPE_LWT_SEG6LOCAL:
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_CGROUP_SKB:
+		if (t == BPF_WRITE)
+			return false;
+		fallthrough;
+
+	/* Program types with direct read + write access go here! */
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_XDP:
+	case BPF_PROG_TYPE_LWT_XMIT:
+	case BPF_PROG_TYPE_SK_SKB:
+	case BPF_PROG_TYPE_SK_MSG:
+		if (meta)
+			return meta->pkt_access;
+
+		env->seen_direct_write = true;
+		return true;
+
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+		if (t == BPF_WRITE)
+			env->seen_direct_write = true;
+
+		return true;
+
+	default:
+		return false;
+	}
+}
+
+static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
+			       int size, bool zero_size_allowed)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = &regs[regno];
+	int err;
+
+	/* We may have added a variable offset to the packet pointer; but any
+	 * reg->range we have comes after that.  We are only checking the fixed
+	 * offset.
+	 */
+
+	/* We don't allow negative numbers, because we aren't tracking enough
+	 * detail to prove they're safe.
+	 */
+	if (reg->smin_value < 0) {
+		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+			regno);
+		return -EACCES;
+	}
+
+	err = reg->range < 0 ? -EINVAL :
+	      __check_mem_access(env, regno, off, size, reg->range,
+				 zero_size_allowed);
+	if (err) {
+		verbose(env, "R%d offset is outside of the packet\n", regno);
+		return err;
+	}
+
+	/* __check_mem_access has made sure "off + size - 1" is within u16.
+	 * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
+	 * otherwise find_good_pkt_pointers would have refused to set range info
+	 * that __check_mem_access would have rejected this pkt access.
+	 * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
+	 */
+	env->prog->aux->max_pkt_offset =
+		max_t(u32, env->prog->aux->max_pkt_offset,
+		      off + reg->umax_value + size - 1);
+
+	return err;
+}
+
+/* check access to 'struct bpf_context' fields.  Supports fixed offsets only */
+static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
+			    enum bpf_access_type t, enum bpf_reg_type *reg_type,
+			    struct btf **btf, u32 *btf_id)
+{
+	struct bpf_insn_access_aux info = {
+		.reg_type = *reg_type,
+		.log = &env->log,
+	};
+
+	if (env->ops->is_valid_access &&
+	    env->ops->is_valid_access(off, size, t, env->prog, &info)) {
+		/* A non zero info.ctx_field_size indicates that this field is a
+		 * candidate for later verifier transformation to load the whole
+		 * field and then apply a mask when accessed with a narrower
+		 * access than actual ctx access size. A zero info.ctx_field_size
+		 * will only allow for whole field access and rejects any other
+		 * type of narrower access.
+		 */
+		*reg_type = info.reg_type;
+
+		if (base_type(*reg_type) == PTR_TO_BTF_ID) {
+			*btf = info.btf;
+			*btf_id = info.btf_id;
+		} else {
+			env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
+		}
+		/* remember the offset of last byte accessed in ctx */
+		if (env->prog->aux->max_ctx_offset < off + size)
+			env->prog->aux->max_ctx_offset = off + size;
+		return 0;
+	}
+
+	verbose(env, "invalid bpf_context access off=%d size=%d\n", off, size);
+	return -EACCES;
+}
+
+static int check_flow_keys_access(struct bpf_verifier_env *env, int off,
+				  int size)
+{
+	if (size < 0 || off < 0 ||
+	    (u64)off + size > sizeof(struct bpf_flow_keys)) {
+		verbose(env, "invalid access to flow keys off=%d size=%d\n",
+			off, size);
+		return -EACCES;
+	}
+	return 0;
+}
+
+static int check_sock_access(struct bpf_verifier_env *env, int insn_idx,
+			     u32 regno, int off, int size,
+			     enum bpf_access_type t)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = &regs[regno];
+	struct bpf_insn_access_aux info = {};
+	bool valid;
+
+	if (reg->smin_value < 0) {
+		verbose(env, "R%d min value is negative, either use unsigned index or do a if (index >=0) check.\n",
+			regno);
+		return -EACCES;
+	}
+
+	switch (reg->type) {
+	case PTR_TO_SOCK_COMMON:
+		valid = bpf_sock_common_is_valid_access(off, size, t, &info);
+		break;
+	case PTR_TO_SOCKET:
+		valid = bpf_sock_is_valid_access(off, size, t, &info);
+		break;
+	case PTR_TO_TCP_SOCK:
+		valid = bpf_tcp_sock_is_valid_access(off, size, t, &info);
+		break;
+	case PTR_TO_XDP_SOCK:
+		valid = bpf_xdp_sock_is_valid_access(off, size, t, &info);
+		break;
+	default:
+		valid = false;
+	}
+
+
+	if (valid) {
+		env->insn_aux_data[insn_idx].ctx_field_size =
+			info.ctx_field_size;
+		return 0;
+	}
+
+	verbose(env, "R%d invalid %s access off=%d size=%d\n",
+		regno, reg_type_str(env, reg->type), off, size);
+
+	return -EACCES;
+}
+
+static bool is_pointer_value(struct bpf_verifier_env *env, int regno)
+{
+	return __is_pointer_value(env->allow_ptr_leaks, reg_state(env, regno));
+}
+
+static bool is_ctx_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	return reg->type == PTR_TO_CTX;
+}
+
+static bool is_sk_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	return type_is_sk_pointer(reg->type);
+}
+
+static bool is_pkt_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	return type_is_pkt_pointer(reg->type);
+}
+
+static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno)
+{
+	const struct bpf_reg_state *reg = reg_state(env, regno);
+
+	/* Separate to is_ctx_reg() since we still want to allow BPF_ST here. */
+	return reg->type == PTR_TO_FLOW_KEYS;
+}
+
+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
+	[CONST_PTR_TO_MAP] = btf_bpf_map_id,
+};
+
+static bool is_trusted_reg(const struct bpf_reg_state *reg)
+{
+	/* A referenced register is always trusted. */
+	if (reg->ref_obj_id)
+		return true;
+
+	/* Types listed in the reg2btf_ids are always trusted */
+	if (reg2btf_ids[base_type(reg->type)])
+		return true;
+
+	/* If a register is not referenced, it is trusted if it has the
+	 * MEM_ALLOC or PTR_TRUSTED type modifiers, and no others. Some of the
+	 * other type modifiers may be safe, but we elect to take an opt-in
+	 * approach here as some (e.g. PTR_UNTRUSTED and PTR_MAYBE_NULL) are
+	 * not.
+	 *
+	 * Eventually, we should make PTR_TRUSTED the single source of truth
+	 * for whether a register is trusted.
+	 */
+	return type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS &&
+	       !bpf_type_has_unsafe_modifiers(reg->type);
+}
+
+static bool is_rcu_reg(const struct bpf_reg_state *reg)
+{
+	return reg->type & MEM_RCU;
+}
+
+static void clear_trusted_flags(enum bpf_type_flag *flag)
+{
+	*flag &= ~(BPF_REG_TRUSTED_MODIFIERS | MEM_RCU);
+}
+
+static int check_pkt_ptr_alignment(struct bpf_verifier_env *env,
+				   const struct bpf_reg_state *reg,
+				   int off, int size, bool strict)
+{
+	struct tnum reg_off;
+	int ip_align;
+
+	/* Byte size accesses are always allowed. */
+	if (!strict || size == 1)
+		return 0;
+
+	/* For platforms that do not have a Kconfig enabling
+	 * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of
+	 * NET_IP_ALIGN is universally set to '2'.  And on platforms
+	 * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get
+	 * to this code only in strict mode where we want to emulate
+	 * the NET_IP_ALIGN==2 checking.  Therefore use an
+	 * unconditional IP align value of '2'.
+	 */
+	ip_align = 2;
+
+	reg_off = tnum_add(reg->var_off, tnum_const(ip_align + reg->off + off));
+	if (!tnum_is_aligned(reg_off, size)) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env,
+			"misaligned packet access off %d+%s+%d+%d size %d\n",
+			ip_align, tn_buf, reg->off, off, size);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int check_generic_ptr_alignment(struct bpf_verifier_env *env,
+				       const struct bpf_reg_state *reg,
+				       const char *pointer_desc,
+				       int off, int size, bool strict)
+{
+	struct tnum reg_off;
+
+	/* Byte size accesses are always allowed. */
+	if (!strict || size == 1)
+		return 0;
+
+	reg_off = tnum_add(reg->var_off, tnum_const(reg->off + off));
+	if (!tnum_is_aligned(reg_off, size)) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "misaligned %saccess off %s+%d+%d size %d\n",
+			pointer_desc, tn_buf, reg->off, off, size);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int check_ptr_alignment(struct bpf_verifier_env *env,
+			       const struct bpf_reg_state *reg, int off,
+			       int size, bool strict_alignment_once)
+{
+	bool strict = env->strict_alignment || strict_alignment_once;
+	const char *pointer_desc = "";
+
+	switch (reg->type) {
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+		/* Special case, because of NET_IP_ALIGN. Given metadata sits
+		 * right in front, treat it the very same way.
+		 */
+		return check_pkt_ptr_alignment(env, reg, off, size, strict);
+	case PTR_TO_FLOW_KEYS:
+		pointer_desc = "flow keys ";
+		break;
+	case PTR_TO_MAP_KEY:
+		pointer_desc = "key ";
+		break;
+	case PTR_TO_MAP_VALUE:
+		pointer_desc = "value ";
+		break;
+	case PTR_TO_CTX:
+		pointer_desc = "context ";
+		break;
+	case PTR_TO_STACK:
+		pointer_desc = "stack ";
+		/* The stack spill tracking logic in check_stack_write_fixed_off()
+		 * and check_stack_read_fixed_off() relies on stack accesses being
+		 * aligned.
+		 */
+		strict = true;
+		break;
+	case PTR_TO_SOCKET:
+		pointer_desc = "sock ";
+		break;
+	case PTR_TO_SOCK_COMMON:
+		pointer_desc = "sock_common ";
+		break;
+	case PTR_TO_TCP_SOCK:
+		pointer_desc = "tcp_sock ";
+		break;
+	case PTR_TO_XDP_SOCK:
+		pointer_desc = "xdp_sock ";
+		break;
+	default:
+		break;
+	}
+	return check_generic_ptr_alignment(env, reg, pointer_desc, off, size,
+					   strict);
+}
+
+/* starting from main bpf function walk all instructions of the function
+ * and recursively walk all callees that given function can call.
+ * Ignore jump and exit insns.
+ * Since recursion is prevented by check_cfg() this algorithm
+ * only needs a local stack of MAX_CALL_FRAMES to remember callsites
+ */
+static int check_max_stack_depth_subprog(struct bpf_verifier_env *env, int idx)
+{
+	struct bpf_subprog_info *subprog = env->subprog_info;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int depth = 0, frame = 0, i, subprog_end;
+	bool tail_call_reachable = false;
+	int ret_insn[MAX_CALL_FRAMES];
+	int ret_prog[MAX_CALL_FRAMES];
+	int j;
+
+	i = subprog[idx].start;
+process_func:
+	/* protect against potential stack overflow that might happen when
+	 * bpf2bpf calls get combined with tailcalls. Limit the caller's stack
+	 * depth for such case down to 256 so that the worst case scenario
+	 * would result in 8k stack size (32 which is tailcall limit * 256 =
+	 * 8k).
+	 *
+	 * To get the idea what might happen, see an example:
+	 * func1 -> sub rsp, 128
+	 *  subfunc1 -> sub rsp, 256
+	 *  tailcall1 -> add rsp, 256
+	 *   func2 -> sub rsp, 192 (total stack size = 128 + 192 = 320)
+	 *   subfunc2 -> sub rsp, 64
+	 *   subfunc22 -> sub rsp, 128
+	 *   tailcall2 -> add rsp, 128
+	 *    func3 -> sub rsp, 32 (total stack size 128 + 192 + 64 + 32 = 416)
+	 *
+	 * tailcall will unwind the current stack frame but it will not get rid
+	 * of caller's stack as shown on the example above.
+	 */
+	if (idx && subprog[idx].has_tail_call && depth >= 256) {
+		verbose(env,
+			"tail_calls are not allowed when call stack of previous frames is %d bytes. Too large\n",
+			depth);
+		return -EACCES;
+	}
+	/* round up to 32-bytes, since this is granularity
+	 * of interpreter stack size
+	 */
+	depth += round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
+	if (depth > MAX_BPF_STACK) {
+		verbose(env, "combined stack size of %d calls is %d. Too large\n",
+			frame + 1, depth);
+		return -EACCES;
+	}
+continue_func:
+	subprog_end = subprog[idx + 1].start;
+	for (; i < subprog_end; i++) {
+		int next_insn, sidx;
+
+		if (!bpf_pseudo_call(insn + i) && !bpf_pseudo_func(insn + i))
+			continue;
+		/* remember insn and function to return to */
+		ret_insn[frame] = i + 1;
+		ret_prog[frame] = idx;
+
+		/* find the callee */
+		next_insn = i + insn[i].imm + 1;
+		sidx = find_subprog(env, next_insn);
+		if (sidx < 0) {
+			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+				  next_insn);
+			return -EFAULT;
+		}
+		if (subprog[sidx].is_async_cb) {
+			if (subprog[sidx].has_tail_call) {
+				verbose(env, "verifier bug. subprog has tail_call and async cb\n");
+				return -EFAULT;
+			}
+			/* async callbacks don't increase bpf prog stack size unless called directly */
+			if (!bpf_pseudo_call(insn + i))
+				continue;
+		}
+		i = next_insn;
+		idx = sidx;
+
+		if (subprog[idx].has_tail_call)
+			tail_call_reachable = true;
+
+		frame++;
+		if (frame >= MAX_CALL_FRAMES) {
+			verbose(env, "the call stack of %d frames is too deep !\n",
+				frame);
+			return -E2BIG;
+		}
+		goto process_func;
+	}
+	/* if tail call got detected across bpf2bpf calls then mark each of the
+	 * currently present subprog frames as tail call reachable subprogs;
+	 * this info will be utilized by JIT so that we will be preserving the
+	 * tail call counter throughout bpf2bpf calls combined with tailcalls
+	 */
+	if (tail_call_reachable)
+		for (j = 0; j < frame; j++)
+			subprog[ret_prog[j]].tail_call_reachable = true;
+	if (subprog[0].tail_call_reachable)
+		env->prog->aux->tail_call_reachable = true;
+
+	/* end of for() loop means the last insn of the 'subprog'
+	 * was reached. Doesn't matter whether it was JA or EXIT
+	 */
+	if (frame == 0)
+		return 0;
+	depth -= round_up(max_t(u32, subprog[idx].stack_depth, 1), 32);
+	frame--;
+	i = ret_insn[frame];
+	idx = ret_prog[frame];
+	goto continue_func;
+}
+
+static int check_max_stack_depth(struct bpf_verifier_env *env)
+{
+	struct bpf_subprog_info *si = env->subprog_info;
+	int ret;
+
+	for (int i = 0; i < env->subprog_cnt; i++) {
+		if (!i || si[i].is_async_cb) {
+			ret = check_max_stack_depth_subprog(env, i);
+			if (ret < 0)
+				return ret;
+		}
+		continue;
+	}
+	return 0;
+}
+
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+static int get_callee_stack_depth(struct bpf_verifier_env *env,
+				  const struct bpf_insn *insn, int idx)
+{
+	int start = idx + insn->imm + 1, subprog;
+
+	subprog = find_subprog(env, start);
+	if (subprog < 0) {
+		WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+			  start);
+		return -EFAULT;
+	}
+	return env->subprog_info[subprog].stack_depth;
+}
+#endif
+
+static int __check_buffer_access(struct bpf_verifier_env *env,
+				 const char *buf_info,
+				 const struct bpf_reg_state *reg,
+				 int regno, int off, int size)
+{
+	if (off < 0) {
+		verbose(env,
+			"R%d invalid %s buffer access: off=%d, size=%d\n",
+			regno, buf_info, off, size);
+		return -EACCES;
+	}
+	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env,
+			"R%d invalid variable buffer offset: off=%d, var_off=%s\n",
+			regno, off, tn_buf);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int check_tp_buffer_access(struct bpf_verifier_env *env,
+				  const struct bpf_reg_state *reg,
+				  int regno, int off, int size)
+{
+	int err;
+
+	err = __check_buffer_access(env, "tracepoint", reg, regno, off, size);
+	if (err)
+		return err;
+
+	if (off + size > env->prog->aux->max_tp_access)
+		env->prog->aux->max_tp_access = off + size;
+
+	return 0;
+}
+
+static int check_buffer_access(struct bpf_verifier_env *env,
+			       const struct bpf_reg_state *reg,
+			       int regno, int off, int size,
+			       bool zero_size_allowed,
+			       u32 *max_access)
+{
+	const char *buf_info = type_is_rdonly_mem(reg->type) ? "rdonly" : "rdwr";
+	int err;
+
+	err = __check_buffer_access(env, buf_info, reg, regno, off, size);
+	if (err)
+		return err;
+
+	if (off + size > *max_access)
+		*max_access = off + size;
+
+	return 0;
+}
+
+/* BPF architecture zero extends alu32 ops into 64-bit registesr */
+static void zext_32_to_64(struct bpf_reg_state *reg)
+{
+	reg->var_off = tnum_subreg(reg->var_off);
+	__reg_assign_32_into_64(reg);
+}
+
+/* truncate register to smaller size (in bytes)
+ * must be called with size < BPF_REG_SIZE
+ */
+static void coerce_reg_to_size(struct bpf_reg_state *reg, int size)
+{
+	u64 mask;
+
+	/* clear high bits in bit representation */
+	reg->var_off = tnum_cast(reg->var_off, size);
+
+	/* fix arithmetic bounds */
+	mask = ((u64)1 << (size * 8)) - 1;
+	if ((reg->umin_value & ~mask) == (reg->umax_value & ~mask)) {
+		reg->umin_value &= mask;
+		reg->umax_value &= mask;
+	} else {
+		reg->umin_value = 0;
+		reg->umax_value = mask;
+	}
+	reg->smin_value = reg->umin_value;
+	reg->smax_value = reg->umax_value;
+
+	/* If size is smaller than 32bit register the 32bit register
+	 * values are also truncated so we push 64-bit bounds into
+	 * 32-bit bounds. Above were truncated < 32-bits already.
+	 */
+	if (size >= 4)
+		return;
+	__reg_combine_64_into_32(reg);
+}
+
+static void set_sext64_default_val(struct bpf_reg_state *reg, int size)
+{
+	if (size == 1) {
+		reg->smin_value = reg->s32_min_value = S8_MIN;
+		reg->smax_value = reg->s32_max_value = S8_MAX;
+	} else if (size == 2) {
+		reg->smin_value = reg->s32_min_value = S16_MIN;
+		reg->smax_value = reg->s32_max_value = S16_MAX;
+	} else {
+		/* size == 4 */
+		reg->smin_value = reg->s32_min_value = S32_MIN;
+		reg->smax_value = reg->s32_max_value = S32_MAX;
+	}
+	reg->umin_value = reg->u32_min_value = 0;
+	reg->umax_value = U64_MAX;
+	reg->u32_max_value = U32_MAX;
+	reg->var_off = tnum_unknown;
+}
+
+static void coerce_reg_to_size_sx(struct bpf_reg_state *reg, int size)
+{
+	s64 init_s64_max, init_s64_min, s64_max, s64_min, u64_cval;
+	u64 top_smax_value, top_smin_value;
+	u64 num_bits = size * 8;
+
+	if (tnum_is_const(reg->var_off)) {
+		u64_cval = reg->var_off.value;
+		if (size == 1)
+			reg->var_off = tnum_const((s8)u64_cval);
+		else if (size == 2)
+			reg->var_off = tnum_const((s16)u64_cval);
+		else
+			/* size == 4 */
+			reg->var_off = tnum_const((s32)u64_cval);
+
+		u64_cval = reg->var_off.value;
+		reg->smax_value = reg->smin_value = u64_cval;
+		reg->umax_value = reg->umin_value = u64_cval;
+		reg->s32_max_value = reg->s32_min_value = u64_cval;
+		reg->u32_max_value = reg->u32_min_value = u64_cval;
+		return;
+	}
+
+	top_smax_value = ((u64)reg->smax_value >> num_bits) << num_bits;
+	top_smin_value = ((u64)reg->smin_value >> num_bits) << num_bits;
+
+	if (top_smax_value != top_smin_value)
+		goto out;
+
+	/* find the s64_min and s64_min after sign extension */
+	if (size == 1) {
+		init_s64_max = (s8)reg->smax_value;
+		init_s64_min = (s8)reg->smin_value;
+	} else if (size == 2) {
+		init_s64_max = (s16)reg->smax_value;
+		init_s64_min = (s16)reg->smin_value;
+	} else {
+		init_s64_max = (s32)reg->smax_value;
+		init_s64_min = (s32)reg->smin_value;
+	}
+
+	s64_max = max(init_s64_max, init_s64_min);
+	s64_min = min(init_s64_max, init_s64_min);
+
+	/* both of s64_max/s64_min positive or negative */
+	if ((s64_max >= 0) == (s64_min >= 0)) {
+		reg->smin_value = reg->s32_min_value = s64_min;
+		reg->smax_value = reg->s32_max_value = s64_max;
+		reg->umin_value = reg->u32_min_value = s64_min;
+		reg->umax_value = reg->u32_max_value = s64_max;
+		reg->var_off = tnum_range(s64_min, s64_max);
+		return;
+	}
+
+out:
+	set_sext64_default_val(reg, size);
+}
+
+static void set_sext32_default_val(struct bpf_reg_state *reg, int size)
+{
+	if (size == 1) {
+		reg->s32_min_value = S8_MIN;
+		reg->s32_max_value = S8_MAX;
+	} else {
+		/* size == 2 */
+		reg->s32_min_value = S16_MIN;
+		reg->s32_max_value = S16_MAX;
+	}
+	reg->u32_min_value = 0;
+	reg->u32_max_value = U32_MAX;
+}
+
+static void coerce_subreg_to_size_sx(struct bpf_reg_state *reg, int size)
+{
+	s32 init_s32_max, init_s32_min, s32_max, s32_min, u32_val;
+	u32 top_smax_value, top_smin_value;
+	u32 num_bits = size * 8;
+
+	if (tnum_is_const(reg->var_off)) {
+		u32_val = reg->var_off.value;
+		if (size == 1)
+			reg->var_off = tnum_const((s8)u32_val);
+		else
+			reg->var_off = tnum_const((s16)u32_val);
+
+		u32_val = reg->var_off.value;
+		reg->s32_min_value = reg->s32_max_value = u32_val;
+		reg->u32_min_value = reg->u32_max_value = u32_val;
+		return;
+	}
+
+	top_smax_value = ((u32)reg->s32_max_value >> num_bits) << num_bits;
+	top_smin_value = ((u32)reg->s32_min_value >> num_bits) << num_bits;
+
+	if (top_smax_value != top_smin_value)
+		goto out;
+
+	/* find the s32_min and s32_min after sign extension */
+	if (size == 1) {
+		init_s32_max = (s8)reg->s32_max_value;
+		init_s32_min = (s8)reg->s32_min_value;
+	} else {
+		/* size == 2 */
+		init_s32_max = (s16)reg->s32_max_value;
+		init_s32_min = (s16)reg->s32_min_value;
+	}
+	s32_max = max(init_s32_max, init_s32_min);
+	s32_min = min(init_s32_max, init_s32_min);
+
+	if ((s32_min >= 0) == (s32_max >= 0)) {
+		reg->s32_min_value = s32_min;
+		reg->s32_max_value = s32_max;
+		reg->u32_min_value = (u32)s32_min;
+		reg->u32_max_value = (u32)s32_max;
+		return;
+	}
+
+out:
+	set_sext32_default_val(reg, size);
+}
+
+static bool bpf_map_is_rdonly(const struct bpf_map *map)
+{
+	/* A map is considered read-only if the following condition are true:
+	 *
+	 * 1) BPF program side cannot change any of the map content. The
+	 *    BPF_F_RDONLY_PROG flag is throughout the lifetime of a map
+	 *    and was set at map creation time.
+	 * 2) The map value(s) have been initialized from user space by a
+	 *    loader and then "frozen", such that no new map update/delete
+	 *    operations from syscall side are possible for the rest of
+	 *    the map's lifetime from that point onwards.
+	 * 3) Any parallel/pending map update/delete operations from syscall
+	 *    side have been completed. Only after that point, it's safe to
+	 *    assume that map value(s) are immutable.
+	 */
+	return (map->map_flags & BPF_F_RDONLY_PROG) &&
+	       READ_ONCE(map->frozen) &&
+	       !bpf_map_write_active(map);
+}
+
+static int bpf_map_direct_read(struct bpf_map *map, int off, int size, u64 *val,
+			       bool is_ldsx)
+{
+	void *ptr;
+	u64 addr;
+	int err;
+
+	err = map->ops->map_direct_value_addr(map, &addr, off);
+	if (err)
+		return err;
+	ptr = (void *)(long)addr + off;
+
+	switch (size) {
+	case sizeof(u8):
+		*val = is_ldsx ? (s64)*(s8 *)ptr : (u64)*(u8 *)ptr;
+		break;
+	case sizeof(u16):
+		*val = is_ldsx ? (s64)*(s16 *)ptr : (u64)*(u16 *)ptr;
+		break;
+	case sizeof(u32):
+		*val = is_ldsx ? (s64)*(s32 *)ptr : (u64)*(u32 *)ptr;
+		break;
+	case sizeof(u64):
+		*val = *(u64 *)ptr;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+#define BTF_TYPE_SAFE_RCU(__type)  __PASTE(__type, __safe_rcu)
+#define BTF_TYPE_SAFE_RCU_OR_NULL(__type)  __PASTE(__type, __safe_rcu_or_null)
+#define BTF_TYPE_SAFE_TRUSTED(__type)  __PASTE(__type, __safe_trusted)
+
+/*
+ * Allow list few fields as RCU trusted or full trusted.
+ * This logic doesn't allow mix tagging and will be removed once GCC supports
+ * btf_type_tag.
+ */
+
+/* RCU trusted: these fields are trusted in RCU CS and never NULL */
+BTF_TYPE_SAFE_RCU(struct task_struct) {
+	const cpumask_t *cpus_ptr;
+	struct css_set __rcu *cgroups;
+	struct task_struct __rcu *real_parent;
+	struct task_struct *group_leader;
+};
+
+BTF_TYPE_SAFE_RCU(struct cgroup) {
+	/* cgrp->kn is always accessible as documented in kernel/cgroup/cgroup.c */
+	struct kernfs_node *kn;
+};
+
+BTF_TYPE_SAFE_RCU(struct css_set) {
+	struct cgroup *dfl_cgrp;
+};
+
+/* RCU trusted: these fields are trusted in RCU CS and can be NULL */
+BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct) {
+	struct file __rcu *exe_file;
+};
+
+/* skb->sk, req->sk are not RCU protected, but we mark them as such
+ * because bpf prog accessible sockets are SOCK_RCU_FREE.
+ */
+BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff) {
+	struct sock *sk;
+};
+
+BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock) {
+	struct sock *sk;
+};
+
+/* full trusted: these fields are trusted even outside of RCU CS and never NULL */
+BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta) {
+	struct seq_file *seq;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task) {
+	struct bpf_iter_meta *meta;
+	struct task_struct *task;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct linux_binprm) {
+	struct file *file;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct file) {
+	struct inode *f_inode;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct dentry) {
+	/* no negative dentry-s in places where bpf can see it */
+	struct inode *d_inode;
+};
+
+BTF_TYPE_SAFE_TRUSTED(struct socket) {
+	struct sock *sk;
+};
+
+static bool type_is_rcu(struct bpf_verifier_env *env,
+			struct bpf_reg_state *reg,
+			const char *field_name, u32 btf_id)
+{
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct task_struct));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct cgroup));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU(struct css_set));
+
+	return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu");
+}
+
+static bool type_is_rcu_or_null(struct bpf_verifier_env *env,
+				struct bpf_reg_state *reg,
+				const char *field_name, u32 btf_id)
+{
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct mm_struct));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct sk_buff));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_RCU_OR_NULL(struct request_sock));
+
+	return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_rcu_or_null");
+}
+
+static bool type_is_trusted(struct bpf_verifier_env *env,
+			    struct bpf_reg_state *reg,
+			    const char *field_name, u32 btf_id)
+{
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter_meta));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct bpf_iter__task));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct linux_binprm));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct file));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct dentry));
+	BTF_TYPE_EMIT(BTF_TYPE_SAFE_TRUSTED(struct socket));
+
+	return btf_nested_type_is_trusted(&env->log, reg, field_name, btf_id, "__safe_trusted");
+}
+
+static int check_ptr_to_btf_access(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *regs,
+				   int regno, int off, int size,
+				   enum bpf_access_type atype,
+				   int value_regno)
+{
+	struct bpf_reg_state *reg = regs + regno;
+	const struct btf_type *t = btf_type_by_id(reg->btf, reg->btf_id);
+	const char *tname = btf_name_by_offset(reg->btf, t->name_off);
+	const char *field_name = NULL;
+	enum bpf_type_flag flag = 0;
+	u32 btf_id = 0;
+	int ret;
+
+	if (!env->allow_ptr_leaks) {
+		verbose(env,
+			"'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
+			tname);
+		return -EPERM;
+	}
+	if (!env->prog->gpl_compatible && btf_is_kernel(reg->btf)) {
+		verbose(env,
+			"Cannot access kernel 'struct %s' from non-GPL compatible program\n",
+			tname);
+		return -EINVAL;
+	}
+	if (off < 0) {
+		verbose(env,
+			"R%d is ptr_%s invalid negative access: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+	if (!tnum_is_const(reg->var_off) || reg->var_off.value) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env,
+			"R%d is ptr_%s invalid variable offset: off=%d, var_off=%s\n",
+			regno, tname, off, tn_buf);
+		return -EACCES;
+	}
+
+	if (reg->type & MEM_USER) {
+		verbose(env,
+			"R%d is ptr_%s access user memory: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+
+	if (reg->type & MEM_PERCPU) {
+		verbose(env,
+			"R%d is ptr_%s access percpu memory: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+
+	if (env->ops->btf_struct_access && !type_is_alloc(reg->type) && atype == BPF_WRITE) {
+		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);
+	} else {
+		/* 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 && !type_is_ptr_alloc_obj(reg->type)) {
+			verbose(env, "only read is supported\n");
+			return -EACCES;
+		}
+
+		if (type_is_alloc(reg->type) && !type_is_non_owning_ref(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, &field_name);
+	}
+
+	if (ret < 0)
+		return ret;
+
+	if (ret != PTR_TO_BTF_ID) {
+		/* just mark; */
+
+	} else if (type_flag(reg->type) & PTR_UNTRUSTED) {
+		/* If this is an untrusted pointer, all pointers formed by walking it
+		 * also inherit the untrusted flag.
+		 */
+		flag = PTR_UNTRUSTED;
+
+	} else if (is_trusted_reg(reg) || is_rcu_reg(reg)) {
+		/* By default any pointer obtained from walking a trusted pointer is no
+		 * longer trusted, unless the field being accessed has explicitly been
+		 * marked as inheriting its parent's state of trust (either full or RCU).
+		 * For example:
+		 * 'cgroups' pointer is untrusted if task->cgroups dereference
+		 * happened in a sleepable program outside of bpf_rcu_read_lock()
+		 * section. In a non-sleepable program it's trusted while in RCU CS (aka MEM_RCU).
+		 * Note bpf_rcu_read_unlock() converts MEM_RCU pointers to PTR_UNTRUSTED.
+		 *
+		 * A regular RCU-protected pointer with __rcu tag can also be deemed
+		 * trusted if we are in an RCU CS. Such pointer can be NULL.
+		 */
+		if (type_is_trusted(env, reg, field_name, btf_id)) {
+			flag |= PTR_TRUSTED;
+		} else if (in_rcu_cs(env) && !type_may_be_null(reg->type)) {
+			if (type_is_rcu(env, reg, field_name, btf_id)) {
+				/* ignore __rcu tag and mark it MEM_RCU */
+				flag |= MEM_RCU;
+			} else if (flag & MEM_RCU ||
+				   type_is_rcu_or_null(env, reg, field_name, btf_id)) {
+				/* __rcu tagged pointers can be NULL */
+				flag |= MEM_RCU | PTR_MAYBE_NULL;
+
+				/* We always trust them */
+				if (type_is_rcu_or_null(env, reg, field_name, btf_id) &&
+				    flag & PTR_UNTRUSTED)
+					flag &= ~PTR_UNTRUSTED;
+			} else if (flag & (MEM_PERCPU | MEM_USER)) {
+				/* keep as-is */
+			} else {
+				/* walking unknown pointers yields old deprecated PTR_TO_BTF_ID */
+				clear_trusted_flags(&flag);
+			}
+		} else {
+			/*
+			 * If not in RCU CS or MEM_RCU pointer can be NULL then
+			 * aggressively mark as untrusted otherwise such
+			 * pointers will be plain PTR_TO_BTF_ID without flags
+			 * and will be allowed to be passed into helpers for
+			 * compat reasons.
+			 */
+			flag = PTR_UNTRUSTED;
+		}
+	} else {
+		/* Old compat. Deprecated */
+		clear_trusted_flags(&flag);
+	}
+
+	if (atype == BPF_READ && value_regno >= 0)
+		mark_btf_ld_reg(env, regs, value_regno, ret, reg->btf, btf_id, flag);
+
+	return 0;
+}
+
+static int check_ptr_to_map_access(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *regs,
+				   int regno, int off, int size,
+				   enum bpf_access_type atype,
+				   int value_regno)
+{
+	struct bpf_reg_state *reg = regs + regno;
+	struct bpf_map *map = reg->map_ptr;
+	struct bpf_reg_state map_reg;
+	enum bpf_type_flag flag = 0;
+	const struct btf_type *t;
+	const char *tname;
+	u32 btf_id;
+	int ret;
+
+	if (!btf_vmlinux) {
+		verbose(env, "map_ptr access not supported without CONFIG_DEBUG_INFO_BTF\n");
+		return -ENOTSUPP;
+	}
+
+	if (!map->ops->map_btf_id || !*map->ops->map_btf_id) {
+		verbose(env, "map_ptr access not supported for map type %d\n",
+			map->map_type);
+		return -ENOTSUPP;
+	}
+
+	t = btf_type_by_id(btf_vmlinux, *map->ops->map_btf_id);
+	tname = btf_name_by_offset(btf_vmlinux, t->name_off);
+
+	if (!env->allow_ptr_leaks) {
+		verbose(env,
+			"'struct %s' access is allowed only to CAP_PERFMON and CAP_SYS_ADMIN\n",
+			tname);
+		return -EPERM;
+	}
+
+	if (off < 0) {
+		verbose(env, "R%d is %s invalid negative access: off=%d\n",
+			regno, tname, off);
+		return -EACCES;
+	}
+
+	if (atype != BPF_READ) {
+		verbose(env, "only read from %s is supported\n", tname);
+		return -EACCES;
+	}
+
+	/* Simulate access to a PTR_TO_BTF_ID */
+	memset(&map_reg, 0, sizeof(map_reg));
+	mark_btf_ld_reg(env, &map_reg, 0, PTR_TO_BTF_ID, btf_vmlinux, *map->ops->map_btf_id, 0);
+	ret = btf_struct_access(&env->log, &map_reg, off, size, atype, &btf_id, &flag, NULL);
+	if (ret < 0)
+		return ret;
+
+	if (value_regno >= 0)
+		mark_btf_ld_reg(env, regs, value_regno, ret, btf_vmlinux, btf_id, flag);
+
+	return 0;
+}
+
+/* Check that the stack access at the given offset is within bounds. The
+ * maximum valid offset is -1.
+ *
+ * The minimum valid offset is -MAX_BPF_STACK for writes, and
+ * -state->allocated_stack for reads.
+ */
+static int check_stack_slot_within_bounds(struct bpf_verifier_env *env,
+                                          s64 off,
+                                          struct bpf_func_state *state,
+                                          enum bpf_access_type t)
+{
+	int min_valid_off;
+
+	if (t == BPF_WRITE || env->allow_uninit_stack)
+		min_valid_off = -MAX_BPF_STACK;
+	else
+		min_valid_off = -state->allocated_stack;
+
+	if (off < min_valid_off || off > -1)
+		return -EACCES;
+	return 0;
+}
+
+/* Check that the stack access at 'regno + off' falls within the maximum stack
+ * bounds.
+ *
+ * 'off' includes `regno->offset`, but not its dynamic part (if any).
+ */
+static int check_stack_access_within_bounds(
+		struct bpf_verifier_env *env,
+		int regno, int off, int access_size,
+		enum bpf_access_src src, enum bpf_access_type type)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = regs + regno;
+	struct bpf_func_state *state = func(env, reg);
+	s64 min_off, max_off;
+	int err;
+	char *err_extra;
+
+	if (src == ACCESS_HELPER)
+		/* We don't know if helpers are reading or writing (or both). */
+		err_extra = " indirect access to";
+	else if (type == BPF_READ)
+		err_extra = " read from";
+	else
+		err_extra = " write to";
+
+	if (tnum_is_const(reg->var_off)) {
+		min_off = (s64)reg->var_off.value + off;
+		max_off = min_off + access_size;
+	} else {
+		if (reg->smax_value >= BPF_MAX_VAR_OFF ||
+		    reg->smin_value <= -BPF_MAX_VAR_OFF) {
+			verbose(env, "invalid unbounded variable-offset%s stack R%d\n",
+				err_extra, regno);
+			return -EACCES;
+		}
+		min_off = reg->smin_value + off;
+		max_off = reg->smax_value + off + access_size;
+	}
+
+	err = check_stack_slot_within_bounds(env, min_off, state, type);
+	if (!err && max_off > 0)
+		err = -EINVAL; /* out of stack access into non-negative offsets */
+
+	if (err) {
+		if (tnum_is_const(reg->var_off)) {
+			verbose(env, "invalid%s stack R%d off=%d size=%d\n",
+				err_extra, regno, off, access_size);
+		} else {
+			char tn_buf[48];
+
+			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+			verbose(env, "invalid variable-offset%s stack R%d var_off=%s size=%d\n",
+				err_extra, regno, tn_buf, access_size);
+		}
+		return err;
+	}
+
+	return grow_stack_state(env, state, round_up(-min_off, BPF_REG_SIZE));
+}
+
+/* check whether memory at (regno + off) is accessible for t = (read | write)
+ * if t==write, value_regno is a register which value is stored into memory
+ * if t==read, value_regno is a register which will receive the value from memory
+ * if t==write && value_regno==-1, some unknown value is stored into memory
+ * if t==read && value_regno==-1, don't care what we read from memory
+ */
+static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regno,
+			    int off, int bpf_size, enum bpf_access_type t,
+			    int value_regno, bool strict_alignment_once, bool is_ldsx)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = regs + regno;
+	int size, err = 0;
+
+	size = bpf_size_to_bytes(bpf_size);
+	if (size < 0)
+		return size;
+
+	/* alignment checks will add in reg->off themselves */
+	err = check_ptr_alignment(env, reg, off, size, strict_alignment_once);
+	if (err)
+		return err;
+
+	/* for access checks, reg->off is just part of off */
+	off += reg->off;
+
+	if (reg->type == PTR_TO_MAP_KEY) {
+		if (t == BPF_WRITE) {
+			verbose(env, "write to change key R%d not allowed\n", regno);
+			return -EACCES;
+		}
+
+		err = check_mem_region_access(env, regno, off, size,
+					      reg->map_ptr->key_size, false);
+		if (err)
+			return err;
+		if (value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_MAP_VALUE) {
+		struct btf_field *kptr_field = NULL;
+
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into map\n", value_regno);
+			return -EACCES;
+		}
+		err = check_map_access_type(env, regno, off, size, t);
+		if (err)
+			return err;
+		err = check_map_access(env, regno, off, size, false, ACCESS_DIRECT);
+		if (err)
+			return err;
+		if (tnum_is_const(reg->var_off))
+			kptr_field = btf_record_find(reg->map_ptr->record,
+						     off + reg->var_off.value, BPF_KPTR);
+		if (kptr_field) {
+			err = check_map_kptr_access(env, regno, value_regno, insn_idx, kptr_field);
+		} else if (t == BPF_READ && value_regno >= 0) {
+			struct bpf_map *map = reg->map_ptr;
+
+			/* if map is read-only, track its contents as scalars */
+			if (tnum_is_const(reg->var_off) &&
+			    bpf_map_is_rdonly(map) &&
+			    map->ops->map_direct_value_addr) {
+				int map_off = off + reg->var_off.value;
+				u64 val = 0;
+
+				err = bpf_map_direct_read(map, map_off, size,
+							  &val, is_ldsx);
+				if (err)
+					return err;
+
+				regs[value_regno].type = SCALAR_VALUE;
+				__mark_reg_known(&regs[value_regno], val);
+			} else {
+				mark_reg_unknown(env, regs, value_regno);
+			}
+		}
+	} else if (base_type(reg->type) == PTR_TO_MEM) {
+		bool rdonly_mem = type_is_rdonly_mem(reg->type);
+
+		if (type_may_be_null(reg->type)) {
+			verbose(env, "R%d invalid mem access '%s'\n", regno,
+				reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+
+		if (t == BPF_WRITE && rdonly_mem) {
+			verbose(env, "R%d cannot write into %s\n",
+				regno, reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into mem\n", value_regno);
+			return -EACCES;
+		}
+
+		err = check_mem_region_access(env, regno, off, size,
+					      reg->mem_size, false);
+		if (!err && value_regno >= 0 && (t == BPF_READ || rdonly_mem))
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_CTX) {
+		enum bpf_reg_type reg_type = SCALAR_VALUE;
+		struct btf *btf = NULL;
+		u32 btf_id = 0;
+
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into ctx\n", value_regno);
+			return -EACCES;
+		}
+
+		err = check_ptr_off_reg(env, reg, regno);
+		if (err < 0)
+			return err;
+
+		err = check_ctx_access(env, insn_idx, off, size, t, &reg_type, &btf,
+				       &btf_id);
+		if (err)
+			verbose_linfo(env, insn_idx, "; ");
+		if (!err && t == BPF_READ && value_regno >= 0) {
+			/* ctx access returns either a scalar, or a
+			 * PTR_TO_PACKET[_META,_END]. In the latter
+			 * case, we know the offset is zero.
+			 */
+			if (reg_type == SCALAR_VALUE) {
+				mark_reg_unknown(env, regs, value_regno);
+			} else {
+				mark_reg_known_zero(env, regs,
+						    value_regno);
+				if (type_may_be_null(reg_type))
+					regs[value_regno].id = ++env->id_gen;
+				/* A load of ctx field could have different
+				 * actual load size with the one encoded in the
+				 * insn. When the dst is PTR, it is for sure not
+				 * a sub-register.
+				 */
+				regs[value_regno].subreg_def = DEF_NOT_SUBREG;
+				if (base_type(reg_type) == PTR_TO_BTF_ID) {
+					regs[value_regno].btf = btf;
+					regs[value_regno].btf_id = btf_id;
+				}
+			}
+			regs[value_regno].type = reg_type;
+		}
+
+	} else if (reg->type == PTR_TO_STACK) {
+		/* Basic bounds checks. */
+		err = check_stack_access_within_bounds(env, regno, off, size, ACCESS_DIRECT, t);
+		if (err)
+			return err;
+
+		if (t == BPF_READ)
+			err = check_stack_read(env, regno, off, size,
+					       value_regno);
+		else
+			err = check_stack_write(env, regno, off, size,
+						value_regno, insn_idx);
+	} else if (reg_is_pkt_pointer(reg)) {
+		if (t == BPF_WRITE && !may_access_direct_pkt_data(env, NULL, t)) {
+			verbose(env, "cannot write into packet\n");
+			return -EACCES;
+		}
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into packet\n",
+				value_regno);
+			return -EACCES;
+		}
+		err = check_packet_access(env, regno, off, size, false);
+		if (!err && t == BPF_READ && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_FLOW_KEYS) {
+		if (t == BPF_WRITE && value_regno >= 0 &&
+		    is_pointer_value(env, value_regno)) {
+			verbose(env, "R%d leaks addr into flow keys\n",
+				value_regno);
+			return -EACCES;
+		}
+
+		err = check_flow_keys_access(env, off, size);
+		if (!err && t == BPF_READ && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (type_is_sk_pointer(reg->type)) {
+		if (t == BPF_WRITE) {
+			verbose(env, "R%d cannot write into %s\n",
+				regno, reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+		err = check_sock_access(env, insn_idx, regno, off, size, t);
+		if (!err && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (reg->type == PTR_TO_TP_BUFFER) {
+		err = check_tp_buffer_access(env, reg, regno, off, size);
+		if (!err && t == BPF_READ && value_regno >= 0)
+			mark_reg_unknown(env, regs, value_regno);
+	} else if (base_type(reg->type) == PTR_TO_BTF_ID &&
+		   !type_may_be_null(reg->type)) {
+		err = check_ptr_to_btf_access(env, regs, regno, off, size, t,
+					      value_regno);
+	} else if (reg->type == CONST_PTR_TO_MAP) {
+		err = check_ptr_to_map_access(env, regs, regno, off, size, t,
+					      value_regno);
+	} else if (base_type(reg->type) == PTR_TO_BUF) {
+		bool rdonly_mem = type_is_rdonly_mem(reg->type);
+		u32 *max_access;
+
+		if (rdonly_mem) {
+			if (t == BPF_WRITE) {
+				verbose(env, "R%d cannot write into %s\n",
+					regno, reg_type_str(env, reg->type));
+				return -EACCES;
+			}
+			max_access = &env->prog->aux->max_rdonly_access;
+		} else {
+			max_access = &env->prog->aux->max_rdwr_access;
+		}
+
+		err = check_buffer_access(env, reg, regno, off, size, false,
+					  max_access);
+
+		if (!err && value_regno >= 0 && (rdonly_mem || t == BPF_READ))
+			mark_reg_unknown(env, regs, value_regno);
+	} else {
+		verbose(env, "R%d invalid mem access '%s'\n", regno,
+			reg_type_str(env, reg->type));
+		return -EACCES;
+	}
+
+	if (!err && size < BPF_REG_SIZE && value_regno >= 0 && t == BPF_READ &&
+	    regs[value_regno].type == SCALAR_VALUE) {
+		if (!is_ldsx)
+			/* b/h/w load zero-extends, mark upper bits as known 0 */
+			coerce_reg_to_size(&regs[value_regno], size);
+		else
+			coerce_reg_to_size_sx(&regs[value_regno], size);
+	}
+	return err;
+}
+
+static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_insn *insn)
+{
+	int load_reg;
+	int err;
+
+	switch (insn->imm) {
+	case BPF_ADD:
+	case BPF_ADD | BPF_FETCH:
+	case BPF_AND:
+	case BPF_AND | BPF_FETCH:
+	case BPF_OR:
+	case BPF_OR | BPF_FETCH:
+	case BPF_XOR:
+	case BPF_XOR | BPF_FETCH:
+	case BPF_XCHG:
+	case BPF_CMPXCHG:
+		break;
+	default:
+		verbose(env, "BPF_ATOMIC uses invalid atomic opcode %02x\n", insn->imm);
+		return -EINVAL;
+	}
+
+	if (BPF_SIZE(insn->code) != BPF_W && BPF_SIZE(insn->code) != BPF_DW) {
+		verbose(env, "invalid atomic operand size\n");
+		return -EINVAL;
+	}
+
+	/* check src1 operand */
+	err = check_reg_arg(env, insn->src_reg, SRC_OP);
+	if (err)
+		return err;
+
+	/* check src2 operand */
+	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+	if (err)
+		return err;
+
+	if (insn->imm == BPF_CMPXCHG) {
+		/* Check comparison of R0 with memory location */
+		const u32 aux_reg = BPF_REG_0;
+
+		err = check_reg_arg(env, aux_reg, SRC_OP);
+		if (err)
+			return err;
+
+		if (is_pointer_value(env, aux_reg)) {
+			verbose(env, "R%d leaks addr into mem\n", aux_reg);
+			return -EACCES;
+		}
+	}
+
+	if (is_pointer_value(env, insn->src_reg)) {
+		verbose(env, "R%d leaks addr into mem\n", insn->src_reg);
+		return -EACCES;
+	}
+
+	if (is_ctx_reg(env, insn->dst_reg) ||
+	    is_pkt_reg(env, insn->dst_reg) ||
+	    is_flow_key_reg(env, insn->dst_reg) ||
+	    is_sk_reg(env, insn->dst_reg)) {
+		verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n",
+			insn->dst_reg,
+			reg_type_str(env, reg_state(env, insn->dst_reg)->type));
+		return -EACCES;
+	}
+
+	if (insn->imm & BPF_FETCH) {
+		if (insn->imm == BPF_CMPXCHG)
+			load_reg = BPF_REG_0;
+		else
+			load_reg = insn->src_reg;
+
+		/* check and record load of old value */
+		err = check_reg_arg(env, load_reg, DST_OP);
+		if (err)
+			return err;
+	} else {
+		/* This instruction accesses a memory location but doesn't
+		 * actually load it into a register.
+		 */
+		load_reg = -1;
+	}
+
+	/* Check whether we can read the memory, with second call for fetch
+	 * case to simulate the register fill.
+	 */
+	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+			       BPF_SIZE(insn->code), BPF_READ, -1, true, false);
+	if (!err && load_reg >= 0)
+		err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+				       BPF_SIZE(insn->code), BPF_READ, load_reg,
+				       true, false);
+	if (err)
+		return err;
+
+	/* Check whether we can write into the same memory. */
+	err = check_mem_access(env, insn_idx, insn->dst_reg, insn->off,
+			       BPF_SIZE(insn->code), BPF_WRITE, -1, true, false);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/* When register 'regno' is used to read the stack (either directly or through
+ * a helper function) make sure that it's within stack boundary and, depending
+ * on the access type and privileges, that all elements of the stack are
+ * initialized.
+ *
+ * 'off' includes 'regno->off', but not its dynamic part (if any).
+ *
+ * All registers that have been spilled on the stack in the slots within the
+ * read offsets are marked as read.
+ */
+static int check_stack_range_initialized(
+		struct bpf_verifier_env *env, int regno, int off,
+		int access_size, bool zero_size_allowed,
+		enum bpf_access_src type, struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *reg = reg_state(env, regno);
+	struct bpf_func_state *state = func(env, reg);
+	int err, min_off, max_off, i, j, slot, spi;
+	char *err_extra = type == ACCESS_HELPER ? " indirect" : "";
+	enum bpf_access_type bounds_check_type;
+	/* Some accesses can write anything into the stack, others are
+	 * read-only.
+	 */
+	bool clobber = false;
+
+	if (access_size == 0 && !zero_size_allowed) {
+		verbose(env, "invalid zero-sized read\n");
+		return -EACCES;
+	}
+
+	if (type == ACCESS_HELPER) {
+		/* The bounds checks for writes are more permissive than for
+		 * reads. However, if raw_mode is not set, we'll do extra
+		 * checks below.
+		 */
+		bounds_check_type = BPF_WRITE;
+		clobber = true;
+	} else {
+		bounds_check_type = BPF_READ;
+	}
+	err = check_stack_access_within_bounds(env, regno, off, access_size,
+					       type, bounds_check_type);
+	if (err)
+		return err;
+
+
+	if (tnum_is_const(reg->var_off)) {
+		min_off = max_off = reg->var_off.value + off;
+	} else {
+		/* Variable offset is prohibited for unprivileged mode for
+		 * simplicity since it requires corresponding support in
+		 * Spectre masking for stack ALU.
+		 * See also retrieve_ptr_limit().
+		 */
+		if (!env->bypass_spec_v1) {
+			char tn_buf[48];
+
+			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+			verbose(env, "R%d%s variable offset stack access prohibited for !root, var_off=%s\n",
+				regno, err_extra, tn_buf);
+			return -EACCES;
+		}
+		/* Only initialized buffer on stack is allowed to be accessed
+		 * with variable offset. With uninitialized buffer it's hard to
+		 * guarantee that whole memory is marked as initialized on
+		 * helper return since specific bounds are unknown what may
+		 * cause uninitialized stack leaking.
+		 */
+		if (meta && meta->raw_mode)
+			meta = NULL;
+
+		min_off = reg->smin_value + off;
+		max_off = reg->smax_value + off;
+	}
+
+	if (meta && meta->raw_mode) {
+		/* Ensure we won't be overwriting dynptrs when simulating byte
+		 * by byte access in check_helper_call using meta.access_size.
+		 * This would be a problem if we have a helper in the future
+		 * which takes:
+		 *
+		 *	helper(uninit_mem, len, dynptr)
+		 *
+		 * Now, uninint_mem may overlap with dynptr pointer. Hence, it
+		 * may end up writing to dynptr itself when touching memory from
+		 * arg 1. This can be relaxed on a case by case basis for known
+		 * safe cases, but reject due to the possibilitiy of aliasing by
+		 * default.
+		 */
+		for (i = min_off; i < max_off + access_size; i++) {
+			int stack_off = -i - 1;
+
+			spi = __get_spi(i);
+			/* raw_mode may write past allocated_stack */
+			if (state->allocated_stack <= stack_off)
+				continue;
+			if (state->stack[spi].slot_type[stack_off % BPF_REG_SIZE] == STACK_DYNPTR) {
+				verbose(env, "potential write to dynptr at off=%d disallowed\n", i);
+				return -EACCES;
+			}
+		}
+		meta->access_size = access_size;
+		meta->regno = regno;
+		return 0;
+	}
+
+	for (i = min_off; i < max_off + access_size; i++) {
+		u8 *stype;
+
+		slot = -i - 1;
+		spi = slot / BPF_REG_SIZE;
+		if (state->allocated_stack <= slot) {
+			verbose(env, "verifier bug: allocated_stack too small");
+			return -EFAULT;
+		}
+
+		stype = &state->stack[spi].slot_type[slot % BPF_REG_SIZE];
+		if (*stype == STACK_MISC)
+			goto mark;
+		if ((*stype == STACK_ZERO) ||
+		    (*stype == STACK_INVALID && env->allow_uninit_stack)) {
+			if (clobber) {
+				/* helper can write anything into the stack */
+				*stype = STACK_MISC;
+			}
+			goto mark;
+		}
+
+		if (is_spilled_reg(&state->stack[spi]) &&
+		    (state->stack[spi].spilled_ptr.type == SCALAR_VALUE ||
+		     env->allow_ptr_leaks)) {
+			if (clobber) {
+				__mark_reg_unknown(env, &state->stack[spi].spilled_ptr);
+				for (j = 0; j < BPF_REG_SIZE; j++)
+					scrub_spilled_slot(&state->stack[spi].slot_type[j]);
+			}
+			goto mark;
+		}
+
+		if (tnum_is_const(reg->var_off)) {
+			verbose(env, "invalid%s read from stack R%d off %d+%d size %d\n",
+				err_extra, regno, min_off, i - min_off, access_size);
+		} else {
+			char tn_buf[48];
+
+			tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+			verbose(env, "invalid%s read from stack R%d var_off %s+%d size %d\n",
+				err_extra, regno, tn_buf, i - min_off, access_size);
+		}
+		return -EACCES;
+mark:
+		/* reading any byte out of 8-byte 'spill_slot' will cause
+		 * the whole slot to be marked as 'read'
+		 */
+		mark_reg_read(env, &state->stack[spi].spilled_ptr,
+			      state->stack[spi].spilled_ptr.parent,
+			      REG_LIVE_READ64);
+		/* We do not set REG_LIVE_WRITTEN for stack slot, as we can not
+		 * be sure that whether stack slot is written to or not. Hence,
+		 * we must still conservatively propagate reads upwards even if
+		 * helper may write to the entire memory range.
+		 */
+	}
+	return 0;
+}
+
+static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
+				   int access_size, bool zero_size_allowed,
+				   struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	u32 *max_access;
+
+	switch (base_type(reg->type)) {
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+		return check_packet_access(env, regno, reg->off, access_size,
+					   zero_size_allowed);
+	case PTR_TO_MAP_KEY:
+		if (meta && meta->raw_mode) {
+			verbose(env, "R%d cannot write into %s\n", regno,
+				reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+		return check_mem_region_access(env, regno, reg->off, access_size,
+					       reg->map_ptr->key_size, false);
+	case PTR_TO_MAP_VALUE:
+		if (check_map_access_type(env, regno, reg->off, access_size,
+					  meta && meta->raw_mode ? BPF_WRITE :
+					  BPF_READ))
+			return -EACCES;
+		return check_map_access(env, regno, reg->off, access_size,
+					zero_size_allowed, ACCESS_HELPER);
+	case PTR_TO_MEM:
+		if (type_is_rdonly_mem(reg->type)) {
+			if (meta && meta->raw_mode) {
+				verbose(env, "R%d cannot write into %s\n", regno,
+					reg_type_str(env, reg->type));
+				return -EACCES;
+			}
+		}
+		return check_mem_region_access(env, regno, reg->off,
+					       access_size, reg->mem_size,
+					       zero_size_allowed);
+	case PTR_TO_BUF:
+		if (type_is_rdonly_mem(reg->type)) {
+			if (meta && meta->raw_mode) {
+				verbose(env, "R%d cannot write into %s\n", regno,
+					reg_type_str(env, reg->type));
+				return -EACCES;
+			}
+
+			max_access = &env->prog->aux->max_rdonly_access;
+		} else {
+			max_access = &env->prog->aux->max_rdwr_access;
+		}
+		return check_buffer_access(env, reg, regno, reg->off,
+					   access_size, zero_size_allowed,
+					   max_access);
+	case PTR_TO_STACK:
+		return check_stack_range_initialized(
+				env,
+				regno, reg->off, access_size,
+				zero_size_allowed, ACCESS_HELPER, meta);
+	case PTR_TO_BTF_ID:
+		return check_ptr_to_btf_access(env, regs, regno, reg->off,
+					       access_size, BPF_READ, -1);
+	case PTR_TO_CTX:
+		/* in case the function doesn't know how to access the context,
+		 * (because we are in a program of type SYSCALL for example), we
+		 * can not statically check its size.
+		 * Dynamically check it now.
+		 */
+		if (!env->ops->convert_ctx_access) {
+			enum bpf_access_type atype = meta && meta->raw_mode ? BPF_WRITE : BPF_READ;
+			int offset = access_size - 1;
+
+			/* Allow zero-byte read from PTR_TO_CTX */
+			if (access_size == 0)
+				return zero_size_allowed ? 0 : -EACCES;
+
+			return check_mem_access(env, env->insn_idx, regno, offset, BPF_B,
+						atype, -1, false, false);
+		}
+
+		fallthrough;
+	default: /* scalar_value or invalid ptr */
+		/* Allow zero-byte read from NULL, regardless of pointer type */
+		if (zero_size_allowed && access_size == 0 &&
+		    register_is_null(reg))
+			return 0;
+
+		verbose(env, "R%d type=%s ", regno,
+			reg_type_str(env, reg->type));
+		verbose(env, "expected=%s\n", reg_type_str(env, PTR_TO_STACK));
+		return -EACCES;
+	}
+}
+
+static int check_mem_size_reg(struct bpf_verifier_env *env,
+			      struct bpf_reg_state *reg, u32 regno,
+			      bool zero_size_allowed,
+			      struct bpf_call_arg_meta *meta)
+{
+	int err;
+
+	/* This is used to refine r0 return value bounds for helpers
+	 * that enforce this value as an upper bound on return values.
+	 * See do_refine_retval_range() for helpers that can refine
+	 * the return value. C type of helper is u32 so we pull register
+	 * bound from umax_value however, if negative verifier errors
+	 * out. Only upper bounds can be learned because retval is an
+	 * int type and negative retvals are allowed.
+	 */
+	meta->msize_max_value = reg->umax_value;
+
+	/* The register is SCALAR_VALUE; the access check
+	 * happens using its boundaries.
+	 */
+	if (!tnum_is_const(reg->var_off))
+		/* For unprivileged variable accesses, disable raw
+		 * mode so that the program is required to
+		 * initialize all the memory that the helper could
+		 * just partially fill up.
+		 */
+		meta = NULL;
+
+	if (reg->smin_value < 0) {
+		verbose(env, "R%d min value is negative, either use unsigned or 'var &= const'\n",
+			regno);
+		return -EACCES;
+	}
+
+	if (reg->umin_value == 0) {
+		err = check_helper_mem_access(env, regno - 1, 0,
+					      zero_size_allowed,
+					      meta);
+		if (err)
+			return err;
+	}
+
+	if (reg->umax_value >= BPF_MAX_VAR_SIZ) {
+		verbose(env, "R%d unbounded memory access, use 'var &= const' or 'if (var < const)'\n",
+			regno);
+		return -EACCES;
+	}
+	err = check_helper_mem_access(env, regno - 1,
+				      reg->umax_value,
+				      zero_size_allowed, meta);
+	if (!err)
+		err = mark_chain_precision(env, regno);
+	return err;
+}
+
+int check_mem_reg(struct bpf_verifier_env *env, struct bpf_reg_state *reg,
+		   u32 regno, u32 mem_size)
+{
+	bool may_be_null = type_may_be_null(reg->type);
+	struct bpf_reg_state saved_reg;
+	struct bpf_call_arg_meta meta;
+	int err;
+
+	if (register_is_null(reg))
+		return 0;
+
+	memset(&meta, 0, sizeof(meta));
+	/* Assuming that the register contains a value check if the memory
+	 * access is safe. Temporarily save and restore the register's state as
+	 * the conversion shouldn't be visible to a caller.
+	 */
+	if (may_be_null) {
+		saved_reg = *reg;
+		mark_ptr_not_null_reg(reg);
+	}
+
+	err = check_helper_mem_access(env, regno, mem_size, true, &meta);
+	/* Check access for BPF_WRITE */
+	meta.raw_mode = true;
+	err = err ?: check_helper_mem_access(env, regno, mem_size, true, &meta);
+
+	if (may_be_null)
+		*reg = saved_reg;
+
+	return err;
+}
+
+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);
+	struct bpf_reg_state saved_reg;
+	struct bpf_call_arg_meta meta;
+	int err;
+
+	WARN_ON_ONCE(regno < BPF_REG_2 || regno > BPF_REG_5);
+
+	memset(&meta, 0, sizeof(meta));
+
+	if (may_be_null) {
+		saved_reg = *mem_reg;
+		mark_ptr_not_null_reg(mem_reg);
+	}
+
+	err = check_mem_size_reg(env, reg, regno, true, &meta);
+	/* Check access for BPF_WRITE */
+	meta.raw_mode = true;
+	err = err ?: check_mem_size_reg(env, reg, regno, true, &meta);
+
+	if (may_be_null)
+		*mem_reg = saved_reg;
+	return err;
+}
+
+/* Implementation details:
+ * 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.
+ * 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. 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_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);
+	u64 val = reg->var_off.value;
+	struct bpf_map *map = NULL;
+	struct btf *btf = NULL;
+	struct btf_record *rec;
+
+	if (!is_const) {
+		verbose(env,
+			"R%d doesn't have constant offset. bpf_spin_lock has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+	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 (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, rec->spin_lock_off);
+		return -EINVAL;
+	}
+	if (is_lock) {
+		if (cur->active_lock.ptr) {
+			verbose(env,
+				"Locking two bpf_spin_locks are not allowed\n");
+			return -EINVAL;
+		}
+		if (map)
+			cur->active_lock.ptr = map;
+		else
+			cur->active_lock.ptr = btf;
+		cur->active_lock.id = reg->id;
+	} else {
+		void *ptr;
+
+		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_lock.ptr != ptr ||
+		    cur->active_lock.id != reg->id) {
+			verbose(env, "bpf_spin_unlock of different lock\n");
+			return -EINVAL;
+		}
+
+		invalidate_non_owning_refs(env);
+
+		cur->active_lock.ptr = NULL;
+		cur->active_lock.id = 0;
+	}
+	return 0;
+}
+
+static int process_timer_func(struct bpf_verifier_env *env, int regno,
+			      struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	bool is_const = tnum_is_const(reg->var_off);
+	struct bpf_map *map = reg->map_ptr;
+	u64 val = reg->var_off.value;
+
+	if (!is_const) {
+		verbose(env,
+			"R%d doesn't have constant offset. bpf_timer has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+	if (!map->btf) {
+		verbose(env, "map '%s' has to have BTF in order to use bpf_timer\n",
+			map->name);
+		return -EINVAL;
+	}
+	if (!btf_record_has_field(map->record, BPF_TIMER)) {
+		verbose(env, "map '%s' has no valid bpf_timer\n", map->name);
+		return -EINVAL;
+	}
+	if (map->record->timer_off != val + reg->off) {
+		verbose(env, "off %lld doesn't point to 'struct bpf_timer' that is at %d\n",
+			val + reg->off, map->record->timer_off);
+		return -EINVAL;
+	}
+	if (meta->map_ptr) {
+		verbose(env, "verifier bug. Two map pointers in a timer helper\n");
+		return -EFAULT;
+	}
+	meta->map_uid = reg->map_uid;
+	meta->map_ptr = map;
+	return 0;
+}
+
+static int process_kptr_func(struct bpf_verifier_env *env, int regno,
+			     struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	struct bpf_map *map_ptr = reg->map_ptr;
+	struct btf_field *kptr_field;
+	u32 kptr_off;
+
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env,
+			"R%d doesn't have constant offset. kptr has to be at the constant offset\n",
+			regno);
+		return -EINVAL;
+	}
+	if (!map_ptr->btf) {
+		verbose(env, "map '%s' has to have BTF in order to use bpf_kptr_xchg\n",
+			map_ptr->name);
+		return -EINVAL;
+	}
+	if (!btf_record_has_field(map_ptr->record, BPF_KPTR)) {
+		verbose(env, "map '%s' has no valid kptr\n", map_ptr->name);
+		return -EINVAL;
+	}
+
+	meta->map_ptr = map_ptr;
+	kptr_off = reg->off + reg->var_off.value;
+	kptr_field = btf_record_find(map_ptr->record, kptr_off, BPF_KPTR);
+	if (!kptr_field) {
+		verbose(env, "off=%d doesn't point to kptr\n", kptr_off);
+		return -EACCES;
+	}
+	if (kptr_field->type != BPF_KPTR_REF) {
+		verbose(env, "off=%d kptr isn't referenced kptr\n", kptr_off);
+		return -EACCES;
+	}
+	meta->kptr_field = kptr_field;
+	return 0;
+}
+
+/* There are two register types representing a bpf_dynptr, one is PTR_TO_STACK
+ * which points to a stack slot, and the other is CONST_PTR_TO_DYNPTR.
+ *
+ * In both cases we deal with the first 8 bytes, but need to mark the next 8
+ * bytes as STACK_DYNPTR in case of PTR_TO_STACK. In case of
+ * CONST_PTR_TO_DYNPTR, we are guaranteed to get the beginning of the object.
+ *
+ * Mutability of bpf_dynptr is at two levels, one is at the level of struct
+ * bpf_dynptr itself, i.e. whether the helper is receiving a pointer to struct
+ * bpf_dynptr or pointer to const struct bpf_dynptr. In the former case, it can
+ * mutate the view of the dynptr and also possibly destroy it. In the latter
+ * case, it cannot mutate the bpf_dynptr itself but it can still mutate the
+ * memory that dynptr points to.
+ *
+ * The verifier will keep track both levels of mutation (bpf_dynptr's in
+ * reg->type and the memory's in reg->dynptr.type), but there is no support for
+ * readonly dynptr view yet, hence only the first case is tracked and checked.
+ *
+ * This is consistent with how C applies the const modifier to a struct object,
+ * where the pointer itself inside bpf_dynptr becomes const but not what it
+ * points to.
+ *
+ * Helpers which do not mutate the bpf_dynptr set MEM_RDONLY in their argument
+ * type, and declare it as 'const struct bpf_dynptr *' in their prototype.
+ */
+static int process_dynptr_func(struct bpf_verifier_env *env, int regno, int insn_idx,
+			       enum bpf_arg_type arg_type, int clone_ref_obj_id)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	int err;
+
+	/* MEM_UNINIT and MEM_RDONLY are exclusive, when applied to an
+	 * ARG_PTR_TO_DYNPTR (or ARG_PTR_TO_DYNPTR | DYNPTR_TYPE_*):
+	 */
+	if ((arg_type & (MEM_UNINIT | MEM_RDONLY)) == (MEM_UNINIT | MEM_RDONLY)) {
+		verbose(env, "verifier internal error: misconfigured dynptr helper type flags\n");
+		return -EFAULT;
+	}
+
+	/*  MEM_UNINIT - Points to memory that is an appropriate candidate for
+	 *		 constructing a mutable bpf_dynptr object.
+	 *
+	 *		 Currently, this is only possible with PTR_TO_STACK
+	 *		 pointing to a region of at least 16 bytes which doesn't
+	 *		 contain an existing bpf_dynptr.
+	 *
+	 *  MEM_RDONLY - Points to a initialized bpf_dynptr that will not be
+	 *		 mutated or destroyed. However, the memory it points to
+	 *		 may be mutated.
+	 *
+	 *  None       - Points to a initialized dynptr that can be mutated and
+	 *		 destroyed, including mutation of the memory it points
+	 *		 to.
+	 */
+	if (arg_type & MEM_UNINIT) {
+		int i;
+
+		if (!is_dynptr_reg_valid_uninit(env, reg)) {
+			verbose(env, "Dynptr has to be an uninitialized dynptr\n");
+			return -EINVAL;
+		}
+
+		/* we write BPF_DW bits (8 bytes) at a time */
+		for (i = 0; i < BPF_DYNPTR_SIZE; i += 8) {
+			err = check_mem_access(env, insn_idx, regno,
+					       i, BPF_DW, BPF_WRITE, -1, false, false);
+			if (err)
+				return err;
+		}
+
+		err = mark_stack_slots_dynptr(env, reg, arg_type, insn_idx, clone_ref_obj_id);
+	} else /* MEM_RDONLY and None case from above */ {
+		/* For the reg->type == PTR_TO_STACK case, bpf_dynptr is never const */
+		if (reg->type == CONST_PTR_TO_DYNPTR && !(arg_type & MEM_RDONLY)) {
+			verbose(env, "cannot pass pointer to const bpf_dynptr, the helper mutates it\n");
+			return -EINVAL;
+		}
+
+		if (!is_dynptr_reg_valid_init(env, reg)) {
+			verbose(env,
+				"Expected an initialized dynptr as arg #%d\n",
+				regno);
+			return -EINVAL;
+		}
+
+		/* Fold modifiers (in this case, MEM_RDONLY) when checking expected type */
+		if (!is_dynptr_type_expected(env, reg, arg_type & ~MEM_RDONLY)) {
+			verbose(env,
+				"Expected a dynptr of type %s as arg #%d\n",
+				dynptr_type_str(arg_to_dynptr_type(arg_type)), regno);
+			return -EINVAL;
+		}
+
+		err = mark_dynptr_read(env, reg);
+	}
+	return err;
+}
+
+static u32 iter_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg, int spi)
+{
+	struct bpf_func_state *state = func(env, reg);
+
+	return state->stack[spi].spilled_ptr.ref_obj_id;
+}
+
+static bool is_iter_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & (KF_ITER_NEW | KF_ITER_NEXT | KF_ITER_DESTROY);
+}
+
+static bool is_iter_new_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_ITER_NEW;
+}
+
+static bool is_iter_next_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_ITER_NEXT;
+}
+
+static bool is_iter_destroy_kfunc(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_ITER_DESTROY;
+}
+
+static bool is_kfunc_arg_iter(struct bpf_kfunc_call_arg_meta *meta, int arg)
+{
+	/* btf_check_iter_kfuncs() guarantees that first argument of any iter
+	 * kfunc is iter state pointer
+	 */
+	return arg == 0 && is_iter_kfunc(meta);
+}
+
+static int process_iter_arg(struct bpf_verifier_env *env, int regno, int insn_idx,
+			    struct bpf_kfunc_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	const struct btf_type *t;
+	const struct btf_param *arg;
+	int spi, err, i, nr_slots;
+	u32 btf_id;
+
+	/* btf_check_iter_kfuncs() ensures we don't need to validate anything here */
+	arg = &btf_params(meta->func_proto)[0];
+	t = btf_type_skip_modifiers(meta->btf, arg->type, NULL);	/* PTR */
+	t = btf_type_skip_modifiers(meta->btf, t->type, &btf_id);	/* STRUCT */
+	nr_slots = t->size / BPF_REG_SIZE;
+
+	if (is_iter_new_kfunc(meta)) {
+		/* bpf_iter_<type>_new() expects pointer to uninit iter state */
+		if (!is_iter_reg_valid_uninit(env, reg, nr_slots)) {
+			verbose(env, "expected uninitialized iter_%s as arg #%d\n",
+				iter_type_str(meta->btf, btf_id), regno);
+			return -EINVAL;
+		}
+
+		for (i = 0; i < nr_slots * 8; i += BPF_REG_SIZE) {
+			err = check_mem_access(env, insn_idx, regno,
+					       i, BPF_DW, BPF_WRITE, -1, false, false);
+			if (err)
+				return err;
+		}
+
+		err = mark_stack_slots_iter(env, reg, insn_idx, meta->btf, btf_id, nr_slots);
+		if (err)
+			return err;
+	} else {
+		/* iter_next() or iter_destroy() expect initialized iter state*/
+		if (!is_iter_reg_valid_init(env, reg, meta->btf, btf_id, nr_slots)) {
+			verbose(env, "expected an initialized iter_%s as arg #%d\n",
+				iter_type_str(meta->btf, btf_id), regno);
+			return -EINVAL;
+		}
+
+		spi = iter_get_spi(env, reg, nr_slots);
+		if (spi < 0)
+			return spi;
+
+		err = mark_iter_read(env, reg, spi, nr_slots);
+		if (err)
+			return err;
+
+		/* remember meta->iter info for process_iter_next_call() */
+		meta->iter.spi = spi;
+		meta->iter.frameno = reg->frameno;
+		meta->ref_obj_id = iter_ref_obj_id(env, reg, spi);
+
+		if (is_iter_destroy_kfunc(meta)) {
+			err = unmark_stack_slots_iter(env, reg, nr_slots);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+/* Look for a previous loop entry at insn_idx: nearest parent state
+ * stopped at insn_idx with callsites matching those in cur->frame.
+ */
+static struct bpf_verifier_state *find_prev_entry(struct bpf_verifier_env *env,
+						  struct bpf_verifier_state *cur,
+						  int insn_idx)
+{
+	struct bpf_verifier_state_list *sl;
+	struct bpf_verifier_state *st;
+
+	/* Explored states are pushed in stack order, most recent states come first */
+	sl = *explored_state(env, insn_idx);
+	for (; sl; sl = sl->next) {
+		/* If st->branches != 0 state is a part of current DFS verification path,
+		 * hence cur & st for a loop.
+		 */
+		st = &sl->state;
+		if (st->insn_idx == insn_idx && st->branches && same_callsites(st, cur) &&
+		    st->dfs_depth < cur->dfs_depth)
+			return st;
+	}
+
+	return NULL;
+}
+
+static void reset_idmap_scratch(struct bpf_verifier_env *env);
+static bool regs_exact(const struct bpf_reg_state *rold,
+		       const struct bpf_reg_state *rcur,
+		       struct bpf_idmap *idmap);
+
+static void maybe_widen_reg(struct bpf_verifier_env *env,
+			    struct bpf_reg_state *rold, struct bpf_reg_state *rcur,
+			    struct bpf_idmap *idmap)
+{
+	if (rold->type != SCALAR_VALUE)
+		return;
+	if (rold->type != rcur->type)
+		return;
+	if (rold->precise || rcur->precise || regs_exact(rold, rcur, idmap))
+		return;
+	__mark_reg_unknown(env, rcur);
+}
+
+static int widen_imprecise_scalars(struct bpf_verifier_env *env,
+				   struct bpf_verifier_state *old,
+				   struct bpf_verifier_state *cur)
+{
+	struct bpf_func_state *fold, *fcur;
+	int i, fr;
+
+	reset_idmap_scratch(env);
+	for (fr = old->curframe; fr >= 0; fr--) {
+		fold = old->frame[fr];
+		fcur = cur->frame[fr];
+
+		for (i = 0; i < MAX_BPF_REG; i++)
+			maybe_widen_reg(env,
+					&fold->regs[i],
+					&fcur->regs[i],
+					&env->idmap_scratch);
+
+		for (i = 0; i < fold->allocated_stack / BPF_REG_SIZE; i++) {
+			if (!is_spilled_reg(&fold->stack[i]) ||
+			    !is_spilled_reg(&fcur->stack[i]))
+				continue;
+
+			maybe_widen_reg(env,
+					&fold->stack[i].spilled_ptr,
+					&fcur->stack[i].spilled_ptr,
+					&env->idmap_scratch);
+		}
+	}
+	return 0;
+}
+
+/* process_iter_next_call() is called when verifier gets to iterator's next
+ * "method" (e.g., bpf_iter_num_next() for numbers iterator) call. We'll refer
+ * to it as just "iter_next()" in comments below.
+ *
+ * BPF verifier relies on a crucial contract for any iter_next()
+ * implementation: it should *eventually* return NULL, and once that happens
+ * it should keep returning NULL. That is, once iterator exhausts elements to
+ * iterate, it should never reset or spuriously return new elements.
+ *
+ * With the assumption of such contract, process_iter_next_call() simulates
+ * a fork in the verifier state to validate loop logic correctness and safety
+ * without having to simulate infinite amount of iterations.
+ *
+ * In current state, we first assume that iter_next() returned NULL and
+ * iterator state is set to DRAINED (BPF_ITER_STATE_DRAINED). In such
+ * conditions we should not form an infinite loop and should eventually reach
+ * exit.
+ *
+ * Besides that, we also fork current state and enqueue it for later
+ * verification. In a forked state we keep iterator state as ACTIVE
+ * (BPF_ITER_STATE_ACTIVE) and assume non-NULL return from iter_next(). We
+ * also bump iteration depth to prevent erroneous infinite loop detection
+ * later on (see iter_active_depths_differ() comment for details). In this
+ * state we assume that we'll eventually loop back to another iter_next()
+ * calls (it could be in exactly same location or in some other instruction,
+ * it doesn't matter, we don't make any unnecessary assumptions about this,
+ * everything revolves around iterator state in a stack slot, not which
+ * instruction is calling iter_next()). When that happens, we either will come
+ * to iter_next() with equivalent state and can conclude that next iteration
+ * will proceed in exactly the same way as we just verified, so it's safe to
+ * assume that loop converges. If not, we'll go on another iteration
+ * simulation with a different input state, until all possible starting states
+ * are validated or we reach maximum number of instructions limit.
+ *
+ * This way, we will either exhaustively discover all possible input states
+ * that iterator loop can start with and eventually will converge, or we'll
+ * effectively regress into bounded loop simulation logic and either reach
+ * maximum number of instructions if loop is not provably convergent, or there
+ * is some statically known limit on number of iterations (e.g., if there is
+ * an explicit `if n > 100 then break;` statement somewhere in the loop).
+ *
+ * Iteration convergence logic in is_state_visited() relies on exact
+ * states comparison, which ignores read and precision marks.
+ * This is necessary because read and precision marks are not finalized
+ * while in the loop. Exact comparison might preclude convergence for
+ * simple programs like below:
+ *
+ *     i = 0;
+ *     while(iter_next(&it))
+ *       i++;
+ *
+ * At each iteration step i++ would produce a new distinct state and
+ * eventually instruction processing limit would be reached.
+ *
+ * To avoid such behavior speculatively forget (widen) range for
+ * imprecise scalar registers, if those registers were not precise at the
+ * end of the previous iteration and do not match exactly.
+ *
+ * This is a conservative heuristic that allows to verify wide range of programs,
+ * however it precludes verification of programs that conjure an
+ * imprecise value on the first loop iteration and use it as precise on a second.
+ * For example, the following safe program would fail to verify:
+ *
+ *     struct bpf_num_iter it;
+ *     int arr[10];
+ *     int i = 0, a = 0;
+ *     bpf_iter_num_new(&it, 0, 10);
+ *     while (bpf_iter_num_next(&it)) {
+ *       if (a == 0) {
+ *         a = 1;
+ *         i = 7; // Because i changed verifier would forget
+ *                // it's range on second loop entry.
+ *       } else {
+ *         arr[i] = 42; // This would fail to verify.
+ *       }
+ *     }
+ *     bpf_iter_num_destroy(&it);
+ */
+static int process_iter_next_call(struct bpf_verifier_env *env, int insn_idx,
+				  struct bpf_kfunc_call_arg_meta *meta)
+{
+	struct bpf_verifier_state *cur_st = env->cur_state, *queued_st, *prev_st;
+	struct bpf_func_state *cur_fr = cur_st->frame[cur_st->curframe], *queued_fr;
+	struct bpf_reg_state *cur_iter, *queued_iter;
+	int iter_frameno = meta->iter.frameno;
+	int iter_spi = meta->iter.spi;
+
+	BTF_TYPE_EMIT(struct bpf_iter);
+
+	cur_iter = &env->cur_state->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
+
+	if (cur_iter->iter.state != BPF_ITER_STATE_ACTIVE &&
+	    cur_iter->iter.state != BPF_ITER_STATE_DRAINED) {
+		verbose(env, "verifier internal error: unexpected iterator state %d (%s)\n",
+			cur_iter->iter.state, iter_state_str(cur_iter->iter.state));
+		return -EFAULT;
+	}
+
+	if (cur_iter->iter.state == BPF_ITER_STATE_ACTIVE) {
+		/* Because iter_next() call is a checkpoint is_state_visitied()
+		 * should guarantee parent state with same call sites and insn_idx.
+		 */
+		if (!cur_st->parent || cur_st->parent->insn_idx != insn_idx ||
+		    !same_callsites(cur_st->parent, cur_st)) {
+			verbose(env, "bug: bad parent state for iter next call");
+			return -EFAULT;
+		}
+		/* Note cur_st->parent in the call below, it is necessary to skip
+		 * checkpoint created for cur_st by is_state_visited()
+		 * right at this instruction.
+		 */
+		prev_st = find_prev_entry(env, cur_st->parent, insn_idx);
+		/* branch out active iter state */
+		queued_st = push_stack(env, insn_idx + 1, insn_idx, false);
+		if (!queued_st)
+			return -ENOMEM;
+
+		queued_iter = &queued_st->frame[iter_frameno]->stack[iter_spi].spilled_ptr;
+		queued_iter->iter.state = BPF_ITER_STATE_ACTIVE;
+		queued_iter->iter.depth++;
+		if (prev_st)
+			widen_imprecise_scalars(env, prev_st, queued_st);
+
+		queued_fr = queued_st->frame[queued_st->curframe];
+		mark_ptr_not_null_reg(&queued_fr->regs[BPF_REG_0]);
+	}
+
+	/* switch to DRAINED state, but keep the depth unchanged */
+	/* mark current iter state as drained and assume returned NULL */
+	cur_iter->iter.state = BPF_ITER_STATE_DRAINED;
+	__mark_reg_const_zero(&cur_fr->regs[BPF_REG_0]);
+
+	return 0;
+}
+
+static bool arg_type_is_mem_size(enum bpf_arg_type type)
+{
+	return type == ARG_CONST_SIZE ||
+	       type == ARG_CONST_SIZE_OR_ZERO;
+}
+
+static bool arg_type_is_release(enum bpf_arg_type type)
+{
+	return type & OBJ_RELEASE;
+}
+
+static bool arg_type_is_dynptr(enum bpf_arg_type type)
+{
+	return base_type(type) == ARG_PTR_TO_DYNPTR;
+}
+
+static int int_ptr_type_to_size(enum bpf_arg_type type)
+{
+	if (type == ARG_PTR_TO_INT)
+		return sizeof(u32);
+	else if (type == ARG_PTR_TO_LONG)
+		return sizeof(u64);
+
+	return -EINVAL;
+}
+
+static int resolve_map_arg_type(struct bpf_verifier_env *env,
+				 const struct bpf_call_arg_meta *meta,
+				 enum bpf_arg_type *arg_type)
+{
+	if (!meta->map_ptr) {
+		/* kernel subsystem misconfigured verifier */
+		verbose(env, "invalid map_ptr to access map->type\n");
+		return -EACCES;
+	}
+
+	switch (meta->map_ptr->map_type) {
+	case BPF_MAP_TYPE_SOCKMAP:
+	case BPF_MAP_TYPE_SOCKHASH:
+		if (*arg_type == ARG_PTR_TO_MAP_VALUE) {
+			*arg_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON;
+		} else {
+			verbose(env, "invalid arg_type for sockmap/sockhash\n");
+			return -EINVAL;
+		}
+		break;
+	case BPF_MAP_TYPE_BLOOM_FILTER:
+		if (meta->func_id == BPF_FUNC_map_peek_elem)
+			*arg_type = ARG_PTR_TO_MAP_VALUE;
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+
+struct bpf_reg_types {
+	const enum bpf_reg_type types[10];
+	u32 *btf_id;
+};
+
+static const struct bpf_reg_types sock_types = {
+	.types = {
+		PTR_TO_SOCK_COMMON,
+		PTR_TO_SOCKET,
+		PTR_TO_TCP_SOCK,
+		PTR_TO_XDP_SOCK,
+	},
+};
+
+#ifdef CONFIG_NET
+static const struct bpf_reg_types btf_id_sock_common_types = {
+	.types = {
+		PTR_TO_SOCK_COMMON,
+		PTR_TO_SOCKET,
+		PTR_TO_TCP_SOCK,
+		PTR_TO_XDP_SOCK,
+		PTR_TO_BTF_ID,
+		PTR_TO_BTF_ID | PTR_TRUSTED,
+	},
+	.btf_id = &btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON],
+};
+#endif
+
+static const struct bpf_reg_types mem_types = {
+	.types = {
+		PTR_TO_STACK,
+		PTR_TO_PACKET,
+		PTR_TO_PACKET_META,
+		PTR_TO_MAP_KEY,
+		PTR_TO_MAP_VALUE,
+		PTR_TO_MEM,
+		PTR_TO_MEM | MEM_RINGBUF,
+		PTR_TO_BUF,
+		PTR_TO_BTF_ID | PTR_TRUSTED,
+	},
+};
+
+static const struct bpf_reg_types int_ptr_types = {
+	.types = {
+		PTR_TO_STACK,
+		PTR_TO_PACKET,
+		PTR_TO_PACKET_META,
+		PTR_TO_MAP_KEY,
+		PTR_TO_MAP_VALUE,
+	},
+};
+
+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,
+		PTR_TO_BTF_ID | PTR_TRUSTED,
+		PTR_TO_BTF_ID | MEM_RCU,
+	},
+};
+static const struct bpf_reg_types percpu_btf_ptr_types = {
+	.types = {
+		PTR_TO_BTF_ID | MEM_PERCPU,
+		PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED,
+	}
+};
+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 } };
+static const struct bpf_reg_types const_str_ptr_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types timer_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types kptr_types = { .types = { PTR_TO_MAP_VALUE } };
+static const struct bpf_reg_types dynptr_types = {
+	.types = {
+		PTR_TO_STACK,
+		CONST_PTR_TO_DYNPTR,
+	}
+};
+
+static const struct bpf_reg_types *compatible_reg_types[__BPF_ARG_TYPE_MAX] = {
+	[ARG_PTR_TO_MAP_KEY]		= &mem_types,
+	[ARG_PTR_TO_MAP_VALUE]		= &mem_types,
+	[ARG_CONST_SIZE]		= &scalar_types,
+	[ARG_CONST_SIZE_OR_ZERO]	= &scalar_types,
+	[ARG_CONST_ALLOC_SIZE_OR_ZERO]	= &scalar_types,
+	[ARG_CONST_MAP_PTR]		= &const_map_ptr_types,
+	[ARG_PTR_TO_CTX]		= &context_types,
+	[ARG_PTR_TO_SOCK_COMMON]	= &sock_types,
+#ifdef CONFIG_NET
+	[ARG_PTR_TO_BTF_ID_SOCK_COMMON]	= &btf_id_sock_common_types,
+#endif
+	[ARG_PTR_TO_SOCKET]		= &fullsock_types,
+	[ARG_PTR_TO_BTF_ID]		= &btf_ptr_types,
+	[ARG_PTR_TO_SPIN_LOCK]		= &spin_lock_types,
+	[ARG_PTR_TO_MEM]		= &mem_types,
+	[ARG_PTR_TO_RINGBUF_MEM]	= &ringbuf_mem_types,
+	[ARG_PTR_TO_INT]		= &int_ptr_types,
+	[ARG_PTR_TO_LONG]		= &int_ptr_types,
+	[ARG_PTR_TO_PERCPU_BTF_ID]	= &percpu_btf_ptr_types,
+	[ARG_PTR_TO_FUNC]		= &func_ptr_types,
+	[ARG_PTR_TO_STACK]		= &stack_ptr_types,
+	[ARG_PTR_TO_CONST_STR]		= &const_str_ptr_types,
+	[ARG_PTR_TO_TIMER]		= &timer_types,
+	[ARG_PTR_TO_KPTR]		= &kptr_types,
+	[ARG_PTR_TO_DYNPTR]		= &dynptr_types,
+};
+
+static int check_reg_type(struct bpf_verifier_env *env, u32 regno,
+			  enum bpf_arg_type arg_type,
+			  const u32 *arg_btf_id,
+			  struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	enum bpf_reg_type expected, type = reg->type;
+	const struct bpf_reg_types *compatible;
+	int i, j;
+
+	compatible = compatible_reg_types[base_type(arg_type)];
+	if (!compatible) {
+		verbose(env, "verifier internal error: unsupported arg type %d\n", arg_type);
+		return -EFAULT;
+	}
+
+	/* ARG_PTR_TO_MEM + RDONLY is compatible with PTR_TO_MEM and PTR_TO_MEM + RDONLY,
+	 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM and NOT with PTR_TO_MEM + RDONLY
+	 *
+	 * Same for MAYBE_NULL:
+	 *
+	 * ARG_PTR_TO_MEM + MAYBE_NULL is compatible with PTR_TO_MEM and PTR_TO_MEM + MAYBE_NULL,
+	 * but ARG_PTR_TO_MEM is compatible only with PTR_TO_MEM but NOT with PTR_TO_MEM + MAYBE_NULL
+	 *
+	 * ARG_PTR_TO_MEM is compatible with PTR_TO_MEM that is tagged with a dynptr type.
+	 *
+	 * Therefore we fold these flags depending on the arg_type before comparison.
+	 */
+	if (arg_type & MEM_RDONLY)
+		type &= ~MEM_RDONLY;
+	if (arg_type & PTR_MAYBE_NULL)
+		type &= ~PTR_MAYBE_NULL;
+	if (base_type(arg_type) == ARG_PTR_TO_MEM)
+		type &= ~DYNPTR_TYPE_FLAG_MASK;
+
+	if (meta->func_id == BPF_FUNC_kptr_xchg && type_is_alloc(type))
+		type &= ~MEM_ALLOC;
+
+	for (i = 0; i < ARRAY_SIZE(compatible->types); i++) {
+		expected = compatible->types[i];
+		if (expected == NOT_INIT)
+			break;
+
+		if (type == expected)
+			goto found;
+	}
+
+	verbose(env, "R%d type=%s expected=", regno, reg_type_str(env, reg->type));
+	for (j = 0; j + 1 < i; j++)
+		verbose(env, "%s, ", reg_type_str(env, compatible->types[j]));
+	verbose(env, "%s\n", reg_type_str(env, compatible->types[j]));
+	return -EACCES;
+
+found:
+	if (base_type(reg->type) != PTR_TO_BTF_ID)
+		return 0;
+
+	if (compatible == &mem_types) {
+		if (!(arg_type & MEM_RDONLY)) {
+			verbose(env,
+				"%s() may write into memory pointed by R%d type=%s\n",
+				func_id_name(meta->func_id),
+				regno, reg_type_str(env, reg->type));
+			return -EACCES;
+		}
+		return 0;
+	}
+
+	switch ((int)reg->type) {
+	case PTR_TO_BTF_ID:
+	case PTR_TO_BTF_ID | PTR_TRUSTED:
+	case PTR_TO_BTF_ID | MEM_RCU:
+	case PTR_TO_BTF_ID | PTR_MAYBE_NULL:
+	case PTR_TO_BTF_ID | PTR_MAYBE_NULL | MEM_RCU:
+	{
+		/* For bpf_sk_release, it needs to match against first member
+		 * 'struct sock_common', hence make an exception for it. This
+		 * allows bpf_sk_release to work for multiple socket types.
+		 */
+		bool strict_type_match = arg_type_is_release(arg_type) &&
+					 meta->func_id != BPF_FUNC_sk_release;
+
+		if (type_may_be_null(reg->type) &&
+		    (!type_may_be_null(arg_type) || arg_type_is_release(arg_type))) {
+			verbose(env, "Possibly NULL pointer passed to helper arg%d\n", regno);
+			return -EACCES;
+		}
+
+		if (!arg_btf_id) {
+			if (!compatible->btf_id) {
+				verbose(env, "verifier internal error: missing arg compatible BTF ID\n");
+				return -EFAULT;
+			}
+			arg_btf_id = compatible->btf_id;
+		}
+
+		if (meta->func_id == BPF_FUNC_kptr_xchg) {
+			if (map_kptr_match_type(env, meta->kptr_field, reg, regno))
+				return -EACCES;
+		} else {
+			if (arg_btf_id == BPF_PTR_POISON) {
+				verbose(env, "verifier internal error:");
+				verbose(env, "R%d has non-overwritten BPF_PTR_POISON type\n",
+					regno);
+				return -EACCES;
+			}
+
+			if (!btf_struct_ids_match(&env->log, reg->btf, reg->btf_id, reg->off,
+						  btf_vmlinux, *arg_btf_id,
+						  strict_type_match)) {
+				verbose(env, "R%d is of type %s but %s is expected\n",
+					regno, btf_type_name(reg->btf, reg->btf_id),
+					btf_type_name(btf_vmlinux, *arg_btf_id));
+				return -EACCES;
+			}
+		}
+		break;
+	}
+	case PTR_TO_BTF_ID | MEM_ALLOC:
+		if (meta->func_id != BPF_FUNC_spin_lock && meta->func_id != BPF_FUNC_spin_unlock &&
+		    meta->func_id != BPF_FUNC_kptr_xchg) {
+			verbose(env, "verifier internal error: unimplemented handling of MEM_ALLOC\n");
+			return -EFAULT;
+		}
+		if (meta->func_id == BPF_FUNC_kptr_xchg) {
+			if (map_kptr_match_type(env, meta->kptr_field, reg, regno))
+				return -EACCES;
+		}
+		break;
+	case PTR_TO_BTF_ID | MEM_PERCPU:
+	case PTR_TO_BTF_ID | MEM_PERCPU | PTR_TRUSTED:
+		/* Handled by helper specific checks */
+		break;
+	default:
+		verbose(env, "verifier internal error: invalid PTR_TO_BTF_ID register for type match\n");
+		return -EFAULT;
+	}
+	return 0;
+}
+
+static struct btf_field *
+reg_find_field_offset(const struct bpf_reg_state *reg, s32 off, u32 fields)
+{
+	struct btf_field *field;
+	struct btf_record *rec;
+
+	rec = reg_btf_record(reg);
+	if (!rec)
+		return NULL;
+
+	field = btf_record_find(rec, off, fields);
+	if (!field)
+		return NULL;
+
+	return field;
+}
+
+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)
+{
+	u32 type = reg->type;
+
+	/* When referenced register is passed to release function, its fixed
+	 * offset must be 0.
+	 *
+	 * We will check arg_type_is_release reg has ref_obj_id when storing
+	 * meta->release_regno.
+	 */
+	if (arg_type_is_release(arg_type)) {
+		/* ARG_PTR_TO_DYNPTR with OBJ_RELEASE is a bit special, as it
+		 * may not directly point to the object being released, but to
+		 * dynptr pointing to such object, which might be at some offset
+		 * on the stack. In that case, we simply to fallback to the
+		 * default handling.
+		 */
+		if (arg_type_is_dynptr(arg_type) && type == PTR_TO_STACK)
+			return 0;
+
+		/* Doing check_ptr_off_reg check for the offset will catch this
+		 * because fixed_off_ok is false, but checking here allows us
+		 * to give the user a better error message.
+		 */
+		if (reg->off) {
+			verbose(env, "R%d must have zero offset when passed to release func or trusted arg to kfunc\n",
+				regno);
+			return -EINVAL;
+		}
+		return __check_ptr_off_reg(env, reg, regno, false);
+	}
+
+	switch (type) {
+	/* Pointer types where both fixed and variable offset is explicitly allowed: */
+	case PTR_TO_STACK:
+	case PTR_TO_PACKET:
+	case PTR_TO_PACKET_META:
+	case PTR_TO_MAP_KEY:
+	case PTR_TO_MAP_VALUE:
+	case PTR_TO_MEM:
+	case PTR_TO_MEM | MEM_RDONLY:
+	case PTR_TO_MEM | MEM_RINGBUF:
+	case PTR_TO_BUF:
+	case PTR_TO_BUF | MEM_RDONLY:
+	case SCALAR_VALUE:
+		return 0;
+	/* All the rest must be rejected, except PTR_TO_BTF_ID which allows
+	 * fixed offset.
+	 */
+	case PTR_TO_BTF_ID:
+	case PTR_TO_BTF_ID | MEM_ALLOC:
+	case PTR_TO_BTF_ID | PTR_TRUSTED:
+	case PTR_TO_BTF_ID | MEM_RCU:
+	case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF:
+	case PTR_TO_BTF_ID | MEM_ALLOC | NON_OWN_REF | MEM_RCU:
+		/* When referenced PTR_TO_BTF_ID is passed to release function,
+		 * its fixed offset must be 0. In the other cases, fixed offset
+		 * can be non-zero. This was already checked above. So pass
+		 * fixed_off_ok as true to allow fixed offset for all other
+		 * cases. var_off always must be 0 for PTR_TO_BTF_ID, hence we
+		 * still need to do checks instead of returning.
+		 */
+		return __check_ptr_off_reg(env, reg, regno, true);
+	default:
+		return __check_ptr_off_reg(env, reg, regno, false);
+	}
+}
+
+static struct bpf_reg_state *get_dynptr_arg_reg(struct bpf_verifier_env *env,
+						const struct bpf_func_proto *fn,
+						struct bpf_reg_state *regs)
+{
+	struct bpf_reg_state *state = NULL;
+	int i;
+
+	for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++)
+		if (arg_type_is_dynptr(fn->arg_type[i])) {
+			if (state) {
+				verbose(env, "verifier internal error: multiple dynptr args\n");
+				return NULL;
+			}
+			state = &regs[BPF_REG_1 + i];
+		}
+
+	if (!state)
+		verbose(env, "verifier internal error: no dynptr arg found\n");
+
+	return state;
+}
+
+static int dynptr_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi;
+
+	if (reg->type == CONST_PTR_TO_DYNPTR)
+		return reg->id;
+	spi = dynptr_get_spi(env, reg);
+	if (spi < 0)
+		return spi;
+	return state->stack[spi].spilled_ptr.id;
+}
+
+static int dynptr_ref_obj_id(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi;
+
+	if (reg->type == CONST_PTR_TO_DYNPTR)
+		return reg->ref_obj_id;
+	spi = dynptr_get_spi(env, reg);
+	if (spi < 0)
+		return spi;
+	return state->stack[spi].spilled_ptr.ref_obj_id;
+}
+
+static enum bpf_dynptr_type dynptr_get_type(struct bpf_verifier_env *env,
+					    struct bpf_reg_state *reg)
+{
+	struct bpf_func_state *state = func(env, reg);
+	int spi;
+
+	if (reg->type == CONST_PTR_TO_DYNPTR)
+		return reg->dynptr.type;
+
+	spi = __get_spi(reg->off);
+	if (spi < 0) {
+		verbose(env, "verifier internal error: invalid spi when querying dynptr type\n");
+		return BPF_DYNPTR_TYPE_INVALID;
+	}
+
+	return state->stack[spi].spilled_ptr.dynptr.type;
+}
+
+static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
+			  struct bpf_call_arg_meta *meta,
+			  const struct bpf_func_proto *fn,
+			  int insn_idx)
+{
+	u32 regno = BPF_REG_1 + arg;
+	struct bpf_reg_state *regs = cur_regs(env), *reg = &regs[regno];
+	enum bpf_arg_type arg_type = fn->arg_type[arg];
+	enum bpf_reg_type type = reg->type;
+	u32 *arg_btf_id = NULL;
+	int err = 0;
+
+	if (arg_type == ARG_DONTCARE)
+		return 0;
+
+	err = check_reg_arg(env, regno, SRC_OP);
+	if (err)
+		return err;
+
+	if (arg_type == ARG_ANYTHING) {
+		if (is_pointer_value(env, regno)) {
+			verbose(env, "R%d leaks addr into helper function\n",
+				regno);
+			return -EACCES;
+		}
+		return 0;
+	}
+
+	if (type_is_pkt_pointer(type) &&
+	    !may_access_direct_pkt_data(env, meta, BPF_READ)) {
+		verbose(env, "helper access to the packet is not allowed\n");
+		return -EACCES;
+	}
+
+	if (base_type(arg_type) == ARG_PTR_TO_MAP_VALUE) {
+		err = resolve_map_arg_type(env, meta, &arg_type);
+		if (err)
+			return err;
+	}
+
+	if (register_is_null(reg) && type_may_be_null(arg_type))
+		/* A NULL register has a SCALAR_VALUE type, so skip
+		 * type checking.
+		 */
+		goto skip_type_check;
+
+	/* arg_btf_id and arg_size are in a union. */
+	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);
+	if (err)
+		return err;
+
+	err = check_func_arg_reg_off(env, reg, regno, arg_type);
+	if (err)
+		return err;
+
+skip_type_check:
+	if (arg_type_is_release(arg_type)) {
+		if (arg_type_is_dynptr(arg_type)) {
+			struct bpf_func_state *state = func(env, reg);
+			int spi;
+
+			/* Only dynptr created on stack can be released, thus
+			 * the get_spi and stack state checks for spilled_ptr
+			 * should only be done before process_dynptr_func for
+			 * PTR_TO_STACK.
+			 */
+			if (reg->type == PTR_TO_STACK) {
+				spi = dynptr_get_spi(env, reg);
+				if (spi < 0 || !state->stack[spi].spilled_ptr.ref_obj_id) {
+					verbose(env, "arg %d is an unacquired reference\n", regno);
+					return -EINVAL;
+				}
+			} else {
+				verbose(env, "cannot release unowned const bpf_dynptr\n");
+				return -EINVAL;
+			}
+		} else if (!reg->ref_obj_id && !register_is_null(reg)) {
+			verbose(env, "R%d must be referenced when passed to release function\n",
+				regno);
+			return -EINVAL;
+		}
+		if (meta->release_regno) {
+			verbose(env, "verifier internal error: more than one release argument\n");
+			return -EFAULT;
+		}
+		meta->release_regno = regno;
+	}
+
+	if (reg->ref_obj_id) {
+		if (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;
+	}
+
+	switch (base_type(arg_type)) {
+	case ARG_CONST_MAP_PTR:
+		/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
+		if (meta->map_ptr) {
+			/* Use map_uid (which is unique id of inner map) to reject:
+			 * inner_map1 = bpf_map_lookup_elem(outer_map, key1)
+			 * inner_map2 = bpf_map_lookup_elem(outer_map, key2)
+			 * if (inner_map1 && inner_map2) {
+			 *     timer = bpf_map_lookup_elem(inner_map1);
+			 *     if (timer)
+			 *         // mismatch would have been allowed
+			 *         bpf_timer_init(timer, inner_map2);
+			 * }
+			 *
+			 * Comparing map_ptr is enough to distinguish normal and outer maps.
+			 */
+			if (meta->map_ptr != reg->map_ptr ||
+			    meta->map_uid != reg->map_uid) {
+				verbose(env,
+					"timer pointer in R1 map_uid=%d doesn't match map pointer in R2 map_uid=%d\n",
+					meta->map_uid, reg->map_uid);
+				return -EINVAL;
+			}
+		}
+		meta->map_ptr = reg->map_ptr;
+		meta->map_uid = reg->map_uid;
+		break;
+	case ARG_PTR_TO_MAP_KEY:
+		/* bpf_map_xxx(..., map_ptr, ..., key) call:
+		 * check that [key, key + map->key_size) are within
+		 * stack limits and initialized
+		 */
+		if (!meta->map_ptr) {
+			/* in function declaration map_ptr must come before
+			 * map_key, so that it's verified and known before
+			 * we have to check map_key here. Otherwise it means
+			 * that kernel subsystem misconfigured verifier
+			 */
+			verbose(env, "invalid map_ptr to access map->key\n");
+			return -EACCES;
+		}
+		err = check_helper_mem_access(env, regno,
+					      meta->map_ptr->key_size, false,
+					      NULL);
+		break;
+	case ARG_PTR_TO_MAP_VALUE:
+		if (type_may_be_null(arg_type) && register_is_null(reg))
+			return 0;
+
+		/* bpf_map_xxx(..., map_ptr, ..., value) call:
+		 * check [value, value + map->value_size) validity
+		 */
+		if (!meta->map_ptr) {
+			/* kernel subsystem misconfigured verifier */
+			verbose(env, "invalid map_ptr to access map->value\n");
+			return -EACCES;
+		}
+		meta->raw_mode = arg_type & MEM_UNINIT;
+		err = check_helper_mem_access(env, regno,
+					      meta->map_ptr->value_size, false,
+					      meta);
+		break;
+	case ARG_PTR_TO_PERCPU_BTF_ID:
+		if (!reg->btf_id) {
+			verbose(env, "Helper has invalid btf_id in R%d\n", regno);
+			return -EACCES;
+		}
+		meta->ret_btf = reg->btf;
+		meta->ret_btf_id = reg->btf_id;
+		break;
+	case ARG_PTR_TO_SPIN_LOCK:
+		if (in_rbtree_lock_required_cb(env)) {
+			verbose(env, "can't spin_{lock,unlock} in rbtree cb\n");
+			return -EACCES;
+		}
+		if (meta->func_id == BPF_FUNC_spin_lock) {
+			err = process_spin_lock(env, regno, true);
+			if (err)
+				return err;
+		} else if (meta->func_id == BPF_FUNC_spin_unlock) {
+			err = process_spin_lock(env, regno, false);
+			if (err)
+				return err;
+		} else {
+			verbose(env, "verifier internal error\n");
+			return -EFAULT;
+		}
+		break;
+	case ARG_PTR_TO_TIMER:
+		err = process_timer_func(env, regno, meta);
+		if (err)
+			return err;
+		break;
+	case ARG_PTR_TO_FUNC:
+		meta->subprogno = reg->subprogno;
+		break;
+	case ARG_PTR_TO_MEM:
+		/* The access to this pointer is only checked when we hit the
+		 * next is_mem_size argument below.
+		 */
+		meta->raw_mode = arg_type & MEM_UNINIT;
+		if (arg_type & MEM_FIXED_SIZE) {
+			err = check_helper_mem_access(env, regno,
+						      fn->arg_size[arg], false,
+						      meta);
+		}
+		break;
+	case ARG_CONST_SIZE:
+		err = check_mem_size_reg(env, reg, regno, false, meta);
+		break;
+	case ARG_CONST_SIZE_OR_ZERO:
+		err = check_mem_size_reg(env, reg, regno, true, meta);
+		break;
+	case ARG_PTR_TO_DYNPTR:
+		err = process_dynptr_func(env, regno, insn_idx, arg_type, 0);
+		if (err)
+			return err;
+		break;
+	case ARG_CONST_ALLOC_SIZE_OR_ZERO:
+		if (!tnum_is_const(reg->var_off)) {
+			verbose(env, "R%d is not a known constant'\n",
+				regno);
+			return -EACCES;
+		}
+		meta->mem_size = reg->var_off.value;
+		err = mark_chain_precision(env, regno);
+		if (err)
+			return err;
+		break;
+	case ARG_PTR_TO_INT:
+	case ARG_PTR_TO_LONG:
+	{
+		int size = int_ptr_type_to_size(arg_type);
+
+		err = check_helper_mem_access(env, regno, size, false, meta);
+		if (err)
+			return err;
+		err = check_ptr_alignment(env, reg, 0, size, true);
+		break;
+	}
+	case ARG_PTR_TO_CONST_STR:
+	{
+		struct bpf_map *map = reg->map_ptr;
+		int map_off;
+		u64 map_addr;
+		char *str_ptr;
+
+		if (!bpf_map_is_rdonly(map)) {
+			verbose(env, "R%d does not point to a readonly map'\n", regno);
+			return -EACCES;
+		}
+
+		if (!tnum_is_const(reg->var_off)) {
+			verbose(env, "R%d is not a constant address'\n", regno);
+			return -EACCES;
+		}
+
+		if (!map->ops->map_direct_value_addr) {
+			verbose(env, "no direct value access support for this map type\n");
+			return -EACCES;
+		}
+
+		err = check_map_access(env, regno, reg->off,
+				       map->value_size - reg->off, false,
+				       ACCESS_HELPER);
+		if (err)
+			return err;
+
+		map_off = reg->off + reg->var_off.value;
+		err = map->ops->map_direct_value_addr(map, &map_addr, map_off);
+		if (err) {
+			verbose(env, "direct value access on string failed\n");
+			return err;
+		}
+
+		str_ptr = (char *)(long)(map_addr);
+		if (!strnchr(str_ptr + map_off, map->value_size - map_off, 0)) {
+			verbose(env, "string is not zero-terminated\n");
+			return -EINVAL;
+		}
+		break;
+	}
+	case ARG_PTR_TO_KPTR:
+		err = process_kptr_func(env, regno, meta);
+		if (err)
+			return err;
+		break;
+	}
+
+	return err;
+}
+
+static bool may_update_sockmap(struct bpf_verifier_env *env, int func_id)
+{
+	enum bpf_attach_type eatype = env->prog->expected_attach_type;
+	enum bpf_prog_type type = resolve_prog_type(env->prog);
+
+	if (func_id != BPF_FUNC_map_update_elem)
+		return false;
+
+	/* It's not possible to get access to a locked struct sock in these
+	 * contexts, so updating is safe.
+	 */
+	switch (type) {
+	case BPF_PROG_TYPE_TRACING:
+		if (eatype == BPF_TRACE_ITER)
+			return true;
+		break;
+	case BPF_PROG_TYPE_SOCKET_FILTER:
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+	case BPF_PROG_TYPE_XDP:
+	case BPF_PROG_TYPE_SK_REUSEPORT:
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		return true;
+	default:
+		break;
+	}
+
+	verbose(env, "cannot update sockmap in this context\n");
+	return false;
+}
+
+static bool allow_tail_call_in_subprogs(struct bpf_verifier_env *env)
+{
+	return env->prog->jit_requested &&
+	       bpf_jit_supports_subprog_tailcalls();
+}
+
+static int check_map_func_compatibility(struct bpf_verifier_env *env,
+					struct bpf_map *map, int func_id)
+{
+	if (!map)
+		return 0;
+
+	/* We need a two way check, first is from map perspective ... */
+	switch (map->map_type) {
+	case BPF_MAP_TYPE_PROG_ARRAY:
+		if (func_id != BPF_FUNC_tail_call)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_PERF_EVENT_ARRAY:
+		if (func_id != BPF_FUNC_perf_event_read &&
+		    func_id != BPF_FUNC_perf_event_output &&
+		    func_id != BPF_FUNC_skb_output &&
+		    func_id != BPF_FUNC_perf_event_read_value &&
+		    func_id != BPF_FUNC_xdp_output)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_RINGBUF:
+		if (func_id != BPF_FUNC_ringbuf_output &&
+		    func_id != BPF_FUNC_ringbuf_reserve &&
+		    func_id != BPF_FUNC_ringbuf_query &&
+		    func_id != BPF_FUNC_ringbuf_reserve_dynptr &&
+		    func_id != BPF_FUNC_ringbuf_submit_dynptr &&
+		    func_id != BPF_FUNC_ringbuf_discard_dynptr)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_USER_RINGBUF:
+		if (func_id != BPF_FUNC_user_ringbuf_drain)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_STACK_TRACE:
+		if (func_id != BPF_FUNC_get_stackid)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_CGROUP_ARRAY:
+		if (func_id != BPF_FUNC_skb_under_cgroup &&
+		    func_id != BPF_FUNC_current_task_under_cgroup)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_CGROUP_STORAGE:
+	case BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE:
+		if (func_id != BPF_FUNC_get_local_storage)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_DEVMAP:
+	case BPF_MAP_TYPE_DEVMAP_HASH:
+		if (func_id != BPF_FUNC_redirect_map &&
+		    func_id != BPF_FUNC_map_lookup_elem)
+			goto error;
+		break;
+	/* Restrict bpf side of cpumap and xskmap, open when use-cases
+	 * appear.
+	 */
+	case BPF_MAP_TYPE_CPUMAP:
+		if (func_id != BPF_FUNC_redirect_map)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_XSKMAP:
+		if (func_id != BPF_FUNC_redirect_map &&
+		    func_id != BPF_FUNC_map_lookup_elem)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+	case BPF_MAP_TYPE_HASH_OF_MAPS:
+		if (func_id != BPF_FUNC_map_lookup_elem)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_SOCKMAP:
+		if (func_id != BPF_FUNC_sk_redirect_map &&
+		    func_id != BPF_FUNC_sock_map_update &&
+		    func_id != BPF_FUNC_map_delete_elem &&
+		    func_id != BPF_FUNC_msg_redirect_map &&
+		    func_id != BPF_FUNC_sk_select_reuseport &&
+		    func_id != BPF_FUNC_map_lookup_elem &&
+		    !may_update_sockmap(env, func_id))
+			goto error;
+		break;
+	case BPF_MAP_TYPE_SOCKHASH:
+		if (func_id != BPF_FUNC_sk_redirect_hash &&
+		    func_id != BPF_FUNC_sock_hash_update &&
+		    func_id != BPF_FUNC_map_delete_elem &&
+		    func_id != BPF_FUNC_msg_redirect_hash &&
+		    func_id != BPF_FUNC_sk_select_reuseport &&
+		    func_id != BPF_FUNC_map_lookup_elem &&
+		    !may_update_sockmap(env, func_id))
+			goto error;
+		break;
+	case BPF_MAP_TYPE_REUSEPORT_SOCKARRAY:
+		if (func_id != BPF_FUNC_sk_select_reuseport)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_QUEUE:
+	case BPF_MAP_TYPE_STACK:
+		if (func_id != BPF_FUNC_map_peek_elem &&
+		    func_id != BPF_FUNC_map_pop_elem &&
+		    func_id != BPF_FUNC_map_push_elem)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_SK_STORAGE:
+		if (func_id != BPF_FUNC_sk_storage_get &&
+		    func_id != BPF_FUNC_sk_storage_delete &&
+		    func_id != BPF_FUNC_kptr_xchg)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_INODE_STORAGE:
+		if (func_id != BPF_FUNC_inode_storage_get &&
+		    func_id != BPF_FUNC_inode_storage_delete &&
+		    func_id != BPF_FUNC_kptr_xchg)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_TASK_STORAGE:
+		if (func_id != BPF_FUNC_task_storage_get &&
+		    func_id != BPF_FUNC_task_storage_delete &&
+		    func_id != BPF_FUNC_kptr_xchg)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_CGRP_STORAGE:
+		if (func_id != BPF_FUNC_cgrp_storage_get &&
+		    func_id != BPF_FUNC_cgrp_storage_delete &&
+		    func_id != BPF_FUNC_kptr_xchg)
+			goto error;
+		break;
+	case BPF_MAP_TYPE_BLOOM_FILTER:
+		if (func_id != BPF_FUNC_map_peek_elem &&
+		    func_id != BPF_FUNC_map_push_elem)
+			goto error;
+		break;
+	default:
+		break;
+	}
+
+	/* ... and second from the function itself. */
+	switch (func_id) {
+	case BPF_FUNC_tail_call:
+		if (map->map_type != BPF_MAP_TYPE_PROG_ARRAY)
+			goto error;
+		if (env->subprog_cnt > 1 && !allow_tail_call_in_subprogs(env)) {
+			verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
+			return -EINVAL;
+		}
+		break;
+	case BPF_FUNC_perf_event_read:
+	case BPF_FUNC_perf_event_output:
+	case BPF_FUNC_perf_event_read_value:
+	case BPF_FUNC_skb_output:
+	case BPF_FUNC_xdp_output:
+		if (map->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY)
+			goto error;
+		break;
+	case BPF_FUNC_ringbuf_output:
+	case BPF_FUNC_ringbuf_reserve:
+	case BPF_FUNC_ringbuf_query:
+	case BPF_FUNC_ringbuf_reserve_dynptr:
+	case BPF_FUNC_ringbuf_submit_dynptr:
+	case BPF_FUNC_ringbuf_discard_dynptr:
+		if (map->map_type != BPF_MAP_TYPE_RINGBUF)
+			goto error;
+		break;
+	case BPF_FUNC_user_ringbuf_drain:
+		if (map->map_type != BPF_MAP_TYPE_USER_RINGBUF)
+			goto error;
+		break;
+	case BPF_FUNC_get_stackid:
+		if (map->map_type != BPF_MAP_TYPE_STACK_TRACE)
+			goto error;
+		break;
+	case BPF_FUNC_current_task_under_cgroup:
+	case BPF_FUNC_skb_under_cgroup:
+		if (map->map_type != BPF_MAP_TYPE_CGROUP_ARRAY)
+			goto error;
+		break;
+	case BPF_FUNC_redirect_map:
+		if (map->map_type != BPF_MAP_TYPE_DEVMAP &&
+		    map->map_type != BPF_MAP_TYPE_DEVMAP_HASH &&
+		    map->map_type != BPF_MAP_TYPE_CPUMAP &&
+		    map->map_type != BPF_MAP_TYPE_XSKMAP)
+			goto error;
+		break;
+	case BPF_FUNC_sk_redirect_map:
+	case BPF_FUNC_msg_redirect_map:
+	case BPF_FUNC_sock_map_update:
+		if (map->map_type != BPF_MAP_TYPE_SOCKMAP)
+			goto error;
+		break;
+	case BPF_FUNC_sk_redirect_hash:
+	case BPF_FUNC_msg_redirect_hash:
+	case BPF_FUNC_sock_hash_update:
+		if (map->map_type != BPF_MAP_TYPE_SOCKHASH)
+			goto error;
+		break;
+	case BPF_FUNC_get_local_storage:
+		if (map->map_type != BPF_MAP_TYPE_CGROUP_STORAGE &&
+		    map->map_type != BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE)
+			goto error;
+		break;
+	case BPF_FUNC_sk_select_reuseport:
+		if (map->map_type != BPF_MAP_TYPE_REUSEPORT_SOCKARRAY &&
+		    map->map_type != BPF_MAP_TYPE_SOCKMAP &&
+		    map->map_type != BPF_MAP_TYPE_SOCKHASH)
+			goto error;
+		break;
+	case BPF_FUNC_map_pop_elem:
+		if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+		    map->map_type != BPF_MAP_TYPE_STACK)
+			goto error;
+		break;
+	case BPF_FUNC_map_peek_elem:
+	case BPF_FUNC_map_push_elem:
+		if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+		    map->map_type != BPF_MAP_TYPE_STACK &&
+		    map->map_type != BPF_MAP_TYPE_BLOOM_FILTER)
+			goto error;
+		break;
+	case BPF_FUNC_map_lookup_percpu_elem:
+		if (map->map_type != BPF_MAP_TYPE_PERCPU_ARRAY &&
+		    map->map_type != BPF_MAP_TYPE_PERCPU_HASH &&
+		    map->map_type != BPF_MAP_TYPE_LRU_PERCPU_HASH)
+			goto error;
+		break;
+	case BPF_FUNC_sk_storage_get:
+	case BPF_FUNC_sk_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
+			goto error;
+		break;
+	case BPF_FUNC_inode_storage_get:
+	case BPF_FUNC_inode_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_INODE_STORAGE)
+			goto error;
+		break;
+	case BPF_FUNC_task_storage_get:
+	case BPF_FUNC_task_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_TASK_STORAGE)
+			goto error;
+		break;
+	case BPF_FUNC_cgrp_storage_get:
+	case BPF_FUNC_cgrp_storage_delete:
+		if (map->map_type != BPF_MAP_TYPE_CGRP_STORAGE)
+			goto error;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+error:
+	verbose(env, "cannot pass map_type %d into func %s#%d\n",
+		map->map_type, func_id_name(func_id), func_id);
+	return -EINVAL;
+}
+
+static bool check_raw_mode_ok(const struct bpf_func_proto *fn)
+{
+	int count = 0;
+
+	if (fn->arg1_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg2_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg3_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg4_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+	if (fn->arg5_type == ARG_PTR_TO_UNINIT_MEM)
+		count++;
+
+	/* We only support one arg being in raw mode at the moment,
+	 * which is sufficient for the helper functions we have
+	 * right now.
+	 */
+	return count <= 1;
+}
+
+static bool check_args_pair_invalid(const struct bpf_func_proto *fn, int arg)
+{
+	bool is_fixed = fn->arg_type[arg] & MEM_FIXED_SIZE;
+	bool has_size = fn->arg_size[arg] != 0;
+	bool is_next_size = false;
+
+	if (arg + 1 < ARRAY_SIZE(fn->arg_type))
+		is_next_size = arg_type_is_mem_size(fn->arg_type[arg + 1]);
+
+	if (base_type(fn->arg_type[arg]) != ARG_PTR_TO_MEM)
+		return is_next_size;
+
+	return has_size == is_next_size || is_next_size == is_fixed;
+}
+
+static bool check_arg_pair_ok(const struct bpf_func_proto *fn)
+{
+	/* bpf_xxx(..., buf, len) call will access 'len'
+	 * bytes from memory 'buf'. Both arg types need
+	 * to be paired, so make sure there's no buggy
+	 * helper function specification.
+	 */
+	if (arg_type_is_mem_size(fn->arg1_type) ||
+	    check_args_pair_invalid(fn, 0) ||
+	    check_args_pair_invalid(fn, 1) ||
+	    check_args_pair_invalid(fn, 2) ||
+	    check_args_pair_invalid(fn, 3) ||
+	    check_args_pair_invalid(fn, 4))
+		return false;
+
+	return true;
+}
+
+static bool check_btf_id_ok(const struct bpf_func_proto *fn)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(fn->arg_type); i++) {
+		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 ||
+		     !(fn->arg_type[i] & MEM_FIXED_SIZE)))
+			return false;
+	}
+
+	return true;
+}
+
+static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
+{
+	return check_raw_mode_ok(fn) &&
+	       check_arg_pair_ok(fn) &&
+	       check_btf_id_ok(fn) ? 0 : -EINVAL;
+}
+
+/* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
+ * are now invalid, so turn them into unknown SCALAR_VALUE.
+ *
+ * This also applies to dynptr slices belonging to skb and xdp dynptrs,
+ * since these slices point to packet data.
+ */
+static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+
+	bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+		if (reg_is_pkt_pointer_any(reg) || reg_is_dynptr_slice_pkt(reg))
+			mark_reg_invalid(env, reg);
+	}));
+}
+
+enum {
+	AT_PKT_END = -1,
+	BEYOND_PKT_END = -2,
+};
+
+static void mark_pkt_end(struct bpf_verifier_state *vstate, int regn, bool range_open)
+{
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *reg = &state->regs[regn];
+
+	if (reg->type != PTR_TO_PACKET)
+		/* PTR_TO_PACKET_META is not supported yet */
+		return;
+
+	/* The 'reg' is pkt > pkt_end or pkt >= pkt_end.
+	 * How far beyond pkt_end it goes is unknown.
+	 * if (!range_open) it's the case of pkt >= pkt_end
+	 * if (range_open) it's the case of pkt > pkt_end
+	 * hence this pointer is at least 1 byte bigger than pkt_end
+	 */
+	if (range_open)
+		reg->range = BEYOND_PKT_END;
+	else
+		reg->range = AT_PKT_END;
+}
+
+/* The pointer with the specified id has released its reference to kernel
+ * resources. Identify all copies of the same pointer and clear the reference.
+ */
+static int release_reference(struct bpf_verifier_env *env,
+			     int ref_obj_id)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+	int err;
+
+	err = release_reference_state(cur_func(env), ref_obj_id);
+	if (err)
+		return err;
+
+	bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+		if (reg->ref_obj_id == ref_obj_id)
+			mark_reg_invalid(env, reg);
+	}));
+
+	return 0;
+}
+
+static void invalidate_non_owning_refs(struct bpf_verifier_env *env)
+{
+	struct bpf_func_state *unused;
+	struct bpf_reg_state *reg;
+
+	bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
+		if (type_is_non_owning_ref(reg->type))
+			mark_reg_invalid(env, reg);
+	}));
+}
+
+static void clear_caller_saved_regs(struct bpf_verifier_env *env,
+				    struct bpf_reg_state *regs)
+{
+	int i;
+
+	/* after the call registers r0 - r5 were scratched */
+	for (i = 0; i < CALLER_SAVED_REGS; i++) {
+		mark_reg_not_init(env, regs, caller_saved[i]);
+		__check_reg_arg(env, regs, caller_saved[i], DST_OP_NO_MARK);
+	}
+}
+
+typedef int (*set_callee_state_fn)(struct bpf_verifier_env *env,
+				   struct bpf_func_state *caller,
+				   struct bpf_func_state *callee,
+				   int insn_idx);
+
+static int set_callee_state(struct bpf_verifier_env *env,
+			    struct bpf_func_state *caller,
+			    struct bpf_func_state *callee, int insn_idx);
+
+static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int callsite,
+			    set_callee_state_fn set_callee_state_cb,
+			    struct bpf_verifier_state *state)
+{
+	struct bpf_func_state *caller, *callee;
+	int err;
+
+	if (state->curframe + 1 >= MAX_CALL_FRAMES) {
+		verbose(env, "the call stack of %d frames is too deep\n",
+			state->curframe + 2);
+		return -E2BIG;
+	}
+
+	if (state->frame[state->curframe + 1]) {
+		verbose(env, "verifier bug. Frame %d already allocated\n",
+			state->curframe + 1);
+		return -EFAULT;
+	}
+
+	caller = state->frame[state->curframe];
+	callee = kzalloc(sizeof(*callee), GFP_KERNEL);
+	if (!callee)
+		return -ENOMEM;
+	state->frame[state->curframe + 1] = callee;
+
+	/* callee cannot access r0, r6 - r9 for reading and has to write
+	 * into its own stack before reading from it.
+	 * callee can read/write into caller's stack
+	 */
+	init_func_state(env, callee,
+			/* remember the callsite, it will be used by bpf_exit */
+			callsite,
+			state->curframe + 1 /* frameno within this callchain */,
+			subprog /* subprog number within this prog */);
+	/* Transfer references to the callee */
+	err = copy_reference_state(callee, caller);
+	err = err ?: set_callee_state_cb(env, caller, callee, callsite);
+	if (err)
+		goto err_out;
+
+	/* only increment it after check_reg_arg() finished */
+	state->curframe++;
+
+	return 0;
+
+err_out:
+	free_func_state(callee);
+	state->frame[state->curframe + 1] = NULL;
+	return err;
+}
+
+static int push_callback_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			      int insn_idx, int subprog,
+			      set_callee_state_fn set_callee_state_cb)
+{
+	struct bpf_verifier_state *state = env->cur_state, *callback_state;
+	struct bpf_func_state *caller, *callee;
+	int err;
+
+	caller = state->frame[state->curframe];
+	err = btf_check_subprog_call(env, subprog, caller->regs);
+	if (err == -EFAULT)
+		return err;
+
+	/* set_callee_state is used for direct subprog calls, but we are
+	 * interested in validating only BPF helpers that can call subprogs as
+	 * callbacks
+	 */
+	if (bpf_pseudo_kfunc_call(insn) &&
+	    !is_sync_callback_calling_kfunc(insn->imm)) {
+		verbose(env, "verifier bug: kfunc %s#%d not marked as callback-calling\n",
+			func_id_name(insn->imm), insn->imm);
+		return -EFAULT;
+	} else if (!bpf_pseudo_kfunc_call(insn) &&
+		   !is_callback_calling_function(insn->imm)) { /* helper */
+		verbose(env, "verifier bug: helper %s#%d not marked as callback-calling\n",
+			func_id_name(insn->imm), insn->imm);
+		return -EFAULT;
+	}
+
+	if (insn->code == (BPF_JMP | BPF_CALL) &&
+	    insn->src_reg == 0 &&
+	    insn->imm == BPF_FUNC_timer_set_callback) {
+		struct bpf_verifier_state *async_cb;
+
+		/* there is no real recursion here. timer callbacks are async */
+		env->subprog_info[subprog].is_async_cb = true;
+		async_cb = push_async_cb(env, env->subprog_info[subprog].start,
+					 insn_idx, subprog);
+		if (!async_cb)
+			return -EFAULT;
+		callee = async_cb->frame[0];
+		callee->async_entry_cnt = caller->async_entry_cnt + 1;
+
+		/* Convert bpf_timer_set_callback() args into timer callback args */
+		err = set_callee_state_cb(env, caller, callee, insn_idx);
+		if (err)
+			return err;
+
+		return 0;
+	}
+
+	/* for callback functions enqueue entry to callback and
+	 * proceed with next instruction within current frame.
+	 */
+	callback_state = push_stack(env, env->subprog_info[subprog].start, insn_idx, false);
+	if (!callback_state)
+		return -ENOMEM;
+
+	err = setup_func_entry(env, subprog, insn_idx, set_callee_state_cb,
+			       callback_state);
+	if (err)
+		return err;
+
+	callback_state->callback_unroll_depth++;
+	callback_state->frame[callback_state->curframe - 1]->callback_depth++;
+	caller->callback_depth = 0;
+	return 0;
+}
+
+static int check_func_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			   int *insn_idx)
+{
+	struct bpf_verifier_state *state = env->cur_state;
+	struct bpf_func_state *caller;
+	int err, subprog, target_insn;
+
+	target_insn = *insn_idx + insn->imm + 1;
+	subprog = find_subprog(env, target_insn);
+	if (subprog < 0) {
+		verbose(env, "verifier bug. No program starts at insn %d\n", target_insn);
+		return -EFAULT;
+	}
+
+	caller = state->frame[state->curframe];
+	err = btf_check_subprog_call(env, subprog, caller->regs);
+	if (err == -EFAULT)
+		return err;
+	if (subprog_is_global(env, subprog)) {
+		if (err) {
+			verbose(env, "Caller passes invalid args into func#%d\n", subprog);
+			return err;
+		}
+
+		if (env->log.level & BPF_LOG_LEVEL)
+			verbose(env, "Func#%d is global and valid. Skipping.\n", subprog);
+		clear_caller_saved_regs(env, caller->regs);
+
+		/* All global functions return a 64-bit SCALAR_VALUE */
+		mark_reg_unknown(env, caller->regs, BPF_REG_0);
+		caller->regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
+		/* continue with next insn after call */
+		return 0;
+	}
+
+	/* for regular function entry setup new frame and continue
+	 * from that frame.
+	 */
+	err = setup_func_entry(env, subprog, *insn_idx, set_callee_state, state);
+	if (err)
+		return err;
+
+	clear_caller_saved_regs(env, caller->regs);
+
+	/* and go analyze first insn of the callee */
+	*insn_idx = env->subprog_info[subprog].start - 1;
+
+	if (env->log.level & BPF_LOG_LEVEL) {
+		verbose(env, "caller:\n");
+		print_verifier_state(env, caller, true);
+		verbose(env, "callee:\n");
+		print_verifier_state(env, state->frame[state->curframe], true);
+	}
+
+	return 0;
+}
+
+int map_set_for_each_callback_args(struct bpf_verifier_env *env,
+				   struct bpf_func_state *caller,
+				   struct bpf_func_state *callee)
+{
+	/* bpf_for_each_map_elem(struct bpf_map *map, void *callback_fn,
+	 *      void *callback_ctx, u64 flags);
+	 * callback_fn(struct bpf_map *map, void *key, void *value,
+	 *      void *callback_ctx);
+	 */
+	callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
+
+	callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+	callee->regs[BPF_REG_2].map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+	callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_3]);
+	callee->regs[BPF_REG_3].map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+	/* pointer to stack or null */
+	callee->regs[BPF_REG_4] = caller->regs[BPF_REG_3];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	return 0;
+}
+
+static int set_callee_state(struct bpf_verifier_env *env,
+			    struct bpf_func_state *caller,
+			    struct bpf_func_state *callee, int insn_idx)
+{
+	int i;
+
+	/* copy r1 - r5 args that callee can access.  The copy includes parent
+	 * pointers, which connects us up to the liveness chain
+	 */
+	for (i = BPF_REG_1; i <= BPF_REG_5; i++)
+		callee->regs[i] = caller->regs[i];
+	return 0;
+}
+
+static int set_map_elem_callback_state(struct bpf_verifier_env *env,
+				       struct bpf_func_state *caller,
+				       struct bpf_func_state *callee,
+				       int insn_idx)
+{
+	struct bpf_insn_aux_data *insn_aux = &env->insn_aux_data[insn_idx];
+	struct bpf_map *map;
+	int err;
+
+	if (bpf_map_ptr_poisoned(insn_aux)) {
+		verbose(env, "tail_call abusing map_ptr\n");
+		return -EINVAL;
+	}
+
+	map = BPF_MAP_PTR(insn_aux->map_ptr_state);
+	if (!map->ops->map_set_for_each_callback_args ||
+	    !map->ops->map_for_each_callback) {
+		verbose(env, "callback function not allowed for map\n");
+		return -ENOTSUPP;
+	}
+
+	err = map->ops->map_set_for_each_callback_args(env, caller, callee);
+	if (err)
+		return err;
+
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_loop_callback_state(struct bpf_verifier_env *env,
+				   struct bpf_func_state *caller,
+				   struct bpf_func_state *callee,
+				   int insn_idx)
+{
+	/* bpf_loop(u32 nr_loops, void *callback_fn, void *callback_ctx,
+	 *	    u64 flags);
+	 * callback_fn(u32 index, void *callback_ctx);
+	 */
+	callee->regs[BPF_REG_1].type = SCALAR_VALUE;
+	callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_timer_callback_state(struct bpf_verifier_env *env,
+				    struct bpf_func_state *caller,
+				    struct bpf_func_state *callee,
+				    int insn_idx)
+{
+	struct bpf_map *map_ptr = caller->regs[BPF_REG_1].map_ptr;
+
+	/* bpf_timer_set_callback(struct bpf_timer *timer, void *callback_fn);
+	 * callback_fn(struct bpf_map *map, void *key, void *value);
+	 */
+	callee->regs[BPF_REG_1].type = CONST_PTR_TO_MAP;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_1]);
+	callee->regs[BPF_REG_1].map_ptr = map_ptr;
+
+	callee->regs[BPF_REG_2].type = PTR_TO_MAP_KEY;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+	callee->regs[BPF_REG_2].map_ptr = map_ptr;
+
+	callee->regs[BPF_REG_3].type = PTR_TO_MAP_VALUE;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_3]);
+	callee->regs[BPF_REG_3].map_ptr = map_ptr;
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	callee->in_async_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_find_vma_callback_state(struct bpf_verifier_env *env,
+				       struct bpf_func_state *caller,
+				       struct bpf_func_state *callee,
+				       int insn_idx)
+{
+	/* bpf_find_vma(struct task_struct *task, u64 addr,
+	 *               void *callback_fn, void *callback_ctx, u64 flags)
+	 * (callback_fn)(struct task_struct *task,
+	 *               struct vm_area_struct *vma, void *callback_ctx);
+	 */
+	callee->regs[BPF_REG_1] = caller->regs[BPF_REG_1];
+
+	callee->regs[BPF_REG_2].type = PTR_TO_BTF_ID;
+	__mark_reg_known_zero(&callee->regs[BPF_REG_2]);
+	callee->regs[BPF_REG_2].btf =  btf_vmlinux;
+	callee->regs[BPF_REG_2].btf_id = btf_tracing_ids[BTF_TRACING_TYPE_VMA],
+
+	/* pointer to stack or null */
+	callee->regs[BPF_REG_3] = caller->regs[BPF_REG_4];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_user_ringbuf_callback_state(struct bpf_verifier_env *env,
+					   struct bpf_func_state *caller,
+					   struct bpf_func_state *callee,
+					   int insn_idx)
+{
+	/* bpf_user_ringbuf_drain(struct bpf_map *map, void *callback_fn, void
+	 *			  callback_ctx, u64 flags);
+	 * callback_fn(const struct bpf_dynptr_t* dynptr, void *callback_ctx);
+	 */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_0]);
+	mark_dynptr_cb_reg(env, &callee->regs[BPF_REG_1], BPF_DYNPTR_TYPE_LOCAL);
+	callee->regs[BPF_REG_2] = caller->regs[BPF_REG_3];
+
+	/* unused */
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static int set_rbtree_add_callback_state(struct bpf_verifier_env *env,
+					 struct bpf_func_state *caller,
+					 struct bpf_func_state *callee,
+					 int insn_idx)
+{
+	/* void bpf_rbtree_add_impl(struct bpf_rb_root *root, struct bpf_rb_node *node,
+	 *                     bool (less)(struct bpf_rb_node *a, const struct bpf_rb_node *b));
+	 *
+	 * 'struct bpf_rb_node *node' arg to bpf_rbtree_add_impl is the same PTR_TO_BTF_ID w/ offset
+	 * that 'less' callback args will be receiving. However, 'node' arg was release_reference'd
+	 * by this point, so look at 'root'
+	 */
+	struct btf_field *field;
+
+	field = reg_find_field_offset(&caller->regs[BPF_REG_1], caller->regs[BPF_REG_1].off,
+				      BPF_RB_ROOT);
+	if (!field || !field->graph_root.value_btf_id)
+		return -EFAULT;
+
+	mark_reg_graph_node(callee->regs, BPF_REG_1, &field->graph_root);
+	ref_set_non_owning(env, &callee->regs[BPF_REG_1]);
+	mark_reg_graph_node(callee->regs, BPF_REG_2, &field->graph_root);
+	ref_set_non_owning(env, &callee->regs[BPF_REG_2]);
+
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_3]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_4]);
+	__mark_reg_not_init(env, &callee->regs[BPF_REG_5]);
+	callee->in_callback_fn = true;
+	callee->callback_ret_range = tnum_range(0, 1);
+	return 0;
+}
+
+static bool is_rbtree_lock_required_kfunc(u32 btf_id);
+
+/* Are we currently verifying the callback for a rbtree helper that must
+ * be called with lock held? If so, no need to complain about unreleased
+ * lock
+ */
+static bool in_rbtree_lock_required_cb(struct bpf_verifier_env *env)
+{
+	struct bpf_verifier_state *state = env->cur_state;
+	struct bpf_insn *insn = env->prog->insnsi;
+	struct bpf_func_state *callee;
+	int kfunc_btf_id;
+
+	if (!state->curframe)
+		return false;
+
+	callee = state->frame[state->curframe];
+
+	if (!callee->in_callback_fn)
+		return false;
+
+	kfunc_btf_id = insn[callee->callsite].imm;
+	return is_rbtree_lock_required_kfunc(kfunc_btf_id);
+}
+
+static int prepare_func_exit(struct bpf_verifier_env *env, int *insn_idx)
+{
+	struct bpf_verifier_state *state = env->cur_state, *prev_st;
+	struct bpf_func_state *caller, *callee;
+	struct bpf_reg_state *r0;
+	bool in_callback_fn;
+	int err;
+
+	callee = state->frame[state->curframe];
+	r0 = &callee->regs[BPF_REG_0];
+	if (r0->type == PTR_TO_STACK) {
+		/* technically it's ok to return caller's stack pointer
+		 * (or caller's caller's pointer) back to the caller,
+		 * since these pointers are valid. Only current stack
+		 * pointer will be invalid as soon as function exits,
+		 * but let's be conservative
+		 */
+		verbose(env, "cannot return stack pointer to the caller\n");
+		return -EINVAL;
+	}
+
+	caller = state->frame[state->curframe - 1];
+	if (callee->in_callback_fn) {
+		/* enforce R0 return value range [0, 1]. */
+		struct tnum range = callee->callback_ret_range;
+
+		if (r0->type != SCALAR_VALUE) {
+			verbose(env, "R0 not a scalar value\n");
+			return -EACCES;
+		}
+
+		/* we are going to rely on register's precise value */
+		err = mark_reg_read(env, r0, r0->parent, REG_LIVE_READ64);
+		err = err ?: mark_chain_precision(env, BPF_REG_0);
+		if (err)
+			return err;
+
+		if (!tnum_in(range, r0->var_off)) {
+			verbose_invalid_scalar(env, r0, &range, "callback return", "R0");
+			return -EINVAL;
+		}
+		if (!calls_callback(env, callee->callsite)) {
+			verbose(env, "BUG: in callback at %d, callsite %d !calls_callback\n",
+				*insn_idx, callee->callsite);
+			return -EFAULT;
+		}
+	} else {
+		/* return to the caller whatever r0 had in the callee */
+		caller->regs[BPF_REG_0] = *r0;
+	}
+
+	/* callback_fn frame should have released its own additions to parent's
+	 * reference state at this point, or check_reference_leak would
+	 * complain, hence it must be the same as the caller. There is no need
+	 * to copy it back.
+	 */
+	if (!callee->in_callback_fn) {
+		/* Transfer references to the caller */
+		err = copy_reference_state(caller, callee);
+		if (err)
+			return err;
+	}
+
+	/* for callbacks like bpf_loop or bpf_for_each_map_elem go back to callsite,
+	 * there function call logic would reschedule callback visit. If iteration
+	 * converges is_state_visited() would prune that visit eventually.
+	 */
+	in_callback_fn = callee->in_callback_fn;
+	if (in_callback_fn)
+		*insn_idx = callee->callsite;
+	else
+		*insn_idx = callee->callsite + 1;
+
+	if (env->log.level & BPF_LOG_LEVEL) {
+		verbose(env, "returning from callee:\n");
+		print_verifier_state(env, callee, true);
+		verbose(env, "to caller at %d:\n", *insn_idx);
+		print_verifier_state(env, caller, true);
+	}
+	/* clear everything in the callee */
+	free_func_state(callee);
+	state->frame[state->curframe--] = NULL;
+
+	/* for callbacks widen imprecise scalars to make programs like below verify:
+	 *
+	 *   struct ctx { int i; }
+	 *   void cb(int idx, struct ctx *ctx) { ctx->i++; ... }
+	 *   ...
+	 *   struct ctx = { .i = 0; }
+	 *   bpf_loop(100, cb, &ctx, 0);
+	 *
+	 * This is similar to what is done in process_iter_next_call() for open
+	 * coded iterators.
+	 */
+	prev_st = in_callback_fn ? find_prev_entry(env, state, *insn_idx) : NULL;
+	if (prev_st) {
+		err = widen_imprecise_scalars(env, prev_st, state);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+static void do_refine_retval_range(struct bpf_reg_state *regs, int ret_type,
+				   int func_id,
+				   struct bpf_call_arg_meta *meta)
+{
+	struct bpf_reg_state *ret_reg = &regs[BPF_REG_0];
+
+	if (ret_type != RET_INTEGER)
+		return;
+
+	switch (func_id) {
+	case BPF_FUNC_get_stack:
+	case BPF_FUNC_get_task_stack:
+	case BPF_FUNC_probe_read_str:
+	case BPF_FUNC_probe_read_kernel_str:
+	case BPF_FUNC_probe_read_user_str:
+		ret_reg->smax_value = meta->msize_max_value;
+		ret_reg->s32_max_value = meta->msize_max_value;
+		ret_reg->smin_value = -MAX_ERRNO;
+		ret_reg->s32_min_value = -MAX_ERRNO;
+		reg_bounds_sync(ret_reg);
+		break;
+	case BPF_FUNC_get_smp_processor_id:
+		ret_reg->umax_value = nr_cpu_ids - 1;
+		ret_reg->u32_max_value = nr_cpu_ids - 1;
+		ret_reg->smax_value = nr_cpu_ids - 1;
+		ret_reg->s32_max_value = nr_cpu_ids - 1;
+		ret_reg->umin_value = 0;
+		ret_reg->u32_min_value = 0;
+		ret_reg->smin_value = 0;
+		ret_reg->s32_min_value = 0;
+		reg_bounds_sync(ret_reg);
+		break;
+	}
+}
+
+static int
+record_func_map(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+		int func_id, int insn_idx)
+{
+	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+	struct bpf_map *map = meta->map_ptr;
+
+	if (func_id != BPF_FUNC_tail_call &&
+	    func_id != BPF_FUNC_map_lookup_elem &&
+	    func_id != BPF_FUNC_map_update_elem &&
+	    func_id != BPF_FUNC_map_delete_elem &&
+	    func_id != BPF_FUNC_map_push_elem &&
+	    func_id != BPF_FUNC_map_pop_elem &&
+	    func_id != BPF_FUNC_map_peek_elem &&
+	    func_id != BPF_FUNC_for_each_map_elem &&
+	    func_id != BPF_FUNC_redirect_map &&
+	    func_id != BPF_FUNC_map_lookup_percpu_elem)
+		return 0;
+
+	if (map == NULL) {
+		verbose(env, "kernel subsystem misconfigured verifier\n");
+		return -EINVAL;
+	}
+
+	/* In case of read-only, some additional restrictions
+	 * need to be applied in order to prevent altering the
+	 * state of the map from program side.
+	 */
+	if ((map->map_flags & BPF_F_RDONLY_PROG) &&
+	    (func_id == BPF_FUNC_map_delete_elem ||
+	     func_id == BPF_FUNC_map_update_elem ||
+	     func_id == BPF_FUNC_map_push_elem ||
+	     func_id == BPF_FUNC_map_pop_elem)) {
+		verbose(env, "write into map forbidden\n");
+		return -EACCES;
+	}
+
+	if (!BPF_MAP_PTR(aux->map_ptr_state))
+		bpf_map_ptr_store(aux, meta->map_ptr,
+				  !meta->map_ptr->bypass_spec_v1);
+	else if (BPF_MAP_PTR(aux->map_ptr_state) != meta->map_ptr)
+		bpf_map_ptr_store(aux, BPF_MAP_PTR_POISON,
+				  !meta->map_ptr->bypass_spec_v1);
+	return 0;
+}
+
+static int
+record_func_key(struct bpf_verifier_env *env, struct bpf_call_arg_meta *meta,
+		int func_id, int insn_idx)
+{
+	struct bpf_insn_aux_data *aux = &env->insn_aux_data[insn_idx];
+	struct bpf_reg_state *regs = cur_regs(env), *reg;
+	struct bpf_map *map = meta->map_ptr;
+	u64 val, max;
+	int err;
+
+	if (func_id != BPF_FUNC_tail_call)
+		return 0;
+	if (!map || map->map_type != BPF_MAP_TYPE_PROG_ARRAY) {
+		verbose(env, "kernel subsystem misconfigured verifier\n");
+		return -EINVAL;
+	}
+
+	reg = &regs[BPF_REG_3];
+	val = reg->var_off.value;
+	max = map->max_entries;
+
+	if (!(register_is_const(reg) && val < max)) {
+		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+		return 0;
+	}
+
+	err = mark_chain_precision(env, BPF_REG_3);
+	if (err)
+		return err;
+	if (bpf_map_key_unseen(aux))
+		bpf_map_key_store(aux, val);
+	else if (!bpf_map_key_poisoned(aux) &&
+		  bpf_map_key_immediate(aux) != val)
+		bpf_map_key_store(aux, BPF_MAP_KEY_POISON);
+	return 0;
+}
+
+static int check_reference_leak(struct bpf_verifier_env *env)
+{
+	struct bpf_func_state *state = cur_func(env);
+	bool refs_lingering = false;
+	int i;
+
+	if (state->frameno && !state->in_callback_fn)
+		return 0;
+
+	for (i = 0; i < state->acquired_refs; i++) {
+		if (state->in_callback_fn && state->refs[i].callback_ref != state->frameno)
+			continue;
+		verbose(env, "Unreleased reference id=%d alloc_insn=%d\n",
+			state->refs[i].id, state->refs[i].insn_idx);
+		refs_lingering = true;
+	}
+	return refs_lingering ? -EINVAL : 0;
+}
+
+static int check_bpf_snprintf_call(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *regs)
+{
+	struct bpf_reg_state *fmt_reg = &regs[BPF_REG_3];
+	struct bpf_reg_state *data_len_reg = &regs[BPF_REG_5];
+	struct bpf_map *fmt_map = fmt_reg->map_ptr;
+	struct bpf_bprintf_data data = {};
+	int err, fmt_map_off, num_args;
+	u64 fmt_addr;
+	char *fmt;
+
+	/* data must be an array of u64 */
+	if (data_len_reg->var_off.value % 8)
+		return -EINVAL;
+	num_args = data_len_reg->var_off.value / 8;
+
+	/* fmt being ARG_PTR_TO_CONST_STR guarantees that var_off is const
+	 * and map_direct_value_addr is set.
+	 */
+	fmt_map_off = fmt_reg->off + fmt_reg->var_off.value;
+	err = fmt_map->ops->map_direct_value_addr(fmt_map, &fmt_addr,
+						  fmt_map_off);
+	if (err) {
+		verbose(env, "verifier bug\n");
+		return -EFAULT;
+	}
+	fmt = (char *)(long)fmt_addr + fmt_map_off;
+
+	/* We are also guaranteed that fmt+fmt_map_off is NULL terminated, we
+	 * can focus on validating the format specifiers.
+	 */
+	err = bpf_bprintf_prepare(fmt, UINT_MAX, NULL, num_args, &data);
+	if (err < 0)
+		verbose(env, "Invalid format string\n");
+
+	return err;
+}
+
+static int check_get_func_ip(struct bpf_verifier_env *env)
+{
+	enum bpf_prog_type type = resolve_prog_type(env->prog);
+	int func_id = BPF_FUNC_get_func_ip;
+
+	if (type == BPF_PROG_TYPE_TRACING) {
+		if (!bpf_prog_has_trampoline(env->prog)) {
+			verbose(env, "func %s#%d supported only for fentry/fexit/fmod_ret programs\n",
+				func_id_name(func_id), func_id);
+			return -ENOTSUPP;
+		}
+		return 0;
+	} else if (type == BPF_PROG_TYPE_KPROBE) {
+		return 0;
+	}
+
+	verbose(env, "func %s#%d not supported for program type %d\n",
+		func_id_name(func_id), func_id, type);
+	return -ENOTSUPP;
+}
+
+static struct bpf_insn_aux_data *cur_aux(struct bpf_verifier_env *env)
+{
+	return &env->insn_aux_data[env->insn_idx];
+}
+
+static bool loop_flag_is_zero(struct bpf_verifier_env *env)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *reg = &regs[BPF_REG_4];
+	bool reg_is_null = register_is_null(reg);
+
+	if (reg_is_null)
+		mark_chain_precision(env, BPF_REG_4);
+
+	return reg_is_null;
+}
+
+static void update_loop_inline_state(struct bpf_verifier_env *env, u32 subprogno)
+{
+	struct bpf_loop_inline_state *state = &cur_aux(env)->loop_inline_state;
+
+	if (!state->initialized) {
+		state->initialized = 1;
+		state->fit_for_inline = loop_flag_is_zero(env);
+		state->callback_subprogno = subprogno;
+		return;
+	}
+
+	if (!state->fit_for_inline)
+		return;
+
+	state->fit_for_inline = (loop_flag_is_zero(env) &&
+				 state->callback_subprogno == subprogno);
+}
+
+static int check_helper_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
+			     int *insn_idx_p)
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+	const struct bpf_func_proto *fn = NULL;
+	enum bpf_return_type ret_type;
+	enum bpf_type_flag ret_flag;
+	struct bpf_reg_state *regs;
+	struct bpf_call_arg_meta meta;
+	int insn_idx = *insn_idx_p;
+	bool changes_data;
+	int i, err, func_id;
+
+	/* find function prototype */
+	func_id = insn->imm;
+	if (func_id < 0 || func_id >= __BPF_FUNC_MAX_ID) {
+		verbose(env, "invalid func %s#%d\n", func_id_name(func_id),
+			func_id);
+		return -EINVAL;
+	}
+
+	if (env->ops->get_func_proto)
+		fn = env->ops->get_func_proto(func_id, env->prog);
+	if (!fn) {
+		verbose(env, "unknown func %s#%d\n", func_id_name(func_id),
+			func_id);
+		return -EINVAL;
+	}
+
+	/* eBPF programs must be GPL compatible to use GPL-ed functions */
+	if (!env->prog->gpl_compatible && fn->gpl_only) {
+		verbose(env, "cannot call GPL-restricted function from non-GPL compatible program\n");
+		return -EINVAL;
+	}
+
+	if (fn->allowed && !fn->allowed(env->prog)) {
+		verbose(env, "helper call is not allowed in probe\n");
+		return -EINVAL;
+	}
+
+	if (!env->prog->aux->sleepable && fn->might_sleep) {
+		verbose(env, "helper call might sleep in a non-sleepable prog\n");
+		return -EINVAL;
+	}
+
+	/* With LD_ABS/IND some JITs save/restore skb from r1. */
+	changes_data = bpf_helper_changes_pkt_data(fn->func);
+	if (changes_data && fn->arg1_type != ARG_PTR_TO_CTX) {
+		verbose(env, "kernel subsystem misconfigured func %s#%d: r1 != ctx\n",
+			func_id_name(func_id), func_id);
+		return -EINVAL;
+	}
+
+	memset(&meta, 0, sizeof(meta));
+	meta.pkt_access = fn->pkt_access;
+
+	err = check_func_proto(fn, func_id);
+	if (err) {
+		verbose(env, "kernel subsystem misconfigured func %s#%d\n",
+			func_id_name(func_id), func_id);
+		return err;
+	}
+
+	if (env->cur_state->active_rcu_lock) {
+		if (fn->might_sleep) {
+			verbose(env, "sleepable helper %s#%d in rcu_read_lock region\n",
+				func_id_name(func_id), func_id);
+			return -EINVAL;
+		}
+
+		if (env->prog->aux->sleepable && is_storage_get_function(func_id))
+			env->insn_aux_data[insn_idx].storage_get_func_atomic = true;
+	}
+
+	meta.func_id = func_id;
+	/* check args */
+	for (i = 0; i < MAX_BPF_FUNC_REG_ARGS; i++) {
+		err = check_func_arg(env, i, &meta, fn, insn_idx);
+		if (err)
+			return err;
+	}
+
+	err = record_func_map(env, &meta, func_id, insn_idx);
+	if (err)
+		return err;
+
+	err = record_func_key(env, &meta, func_id, insn_idx);
+	if (err)
+		return err;
+
+	/* Mark slots with STACK_MISC in case of raw mode, stack offset
+	 * is inferred from register state.
+	 */
+	for (i = 0; i < meta.access_size; i++) {
+		err = check_mem_access(env, insn_idx, meta.regno, i, BPF_B,
+				       BPF_WRITE, -1, false, false);
+		if (err)
+			return err;
+	}
+
+	regs = cur_regs(env);
+
+	if (meta.release_regno) {
+		err = -EINVAL;
+		/* This can only be set for PTR_TO_STACK, as CONST_PTR_TO_DYNPTR cannot
+		 * be released by any dynptr helper. Hence, unmark_stack_slots_dynptr
+		 * is safe to do directly.
+		 */
+		if (arg_type_is_dynptr(fn->arg_type[meta.release_regno - BPF_REG_1])) {
+			if (regs[meta.release_regno].type == CONST_PTR_TO_DYNPTR) {
+				verbose(env, "verifier internal error: CONST_PTR_TO_DYNPTR cannot be released\n");
+				return -EFAULT;
+			}
+			err = unmark_stack_slots_dynptr(env, &regs[meta.release_regno]);
+		} else if (meta.ref_obj_id) {
+			err = release_reference(env, meta.ref_obj_id);
+		} else if (register_is_null(&regs[meta.release_regno])) {
+			/* meta.ref_obj_id can only be 0 if register that is meant to be
+			 * released is NULL, which must be > R0.
+			 */
+			err = 0;
+		}
+		if (err) {
+			verbose(env, "func %s#%d reference has not been acquired before\n",
+				func_id_name(func_id), func_id);
+			return err;
+		}
+	}
+
+	switch (func_id) {
+	case BPF_FUNC_tail_call:
+		err = check_reference_leak(env);
+		if (err) {
+			verbose(env, "tail_call would lead to reference leak\n");
+			return err;
+		}
+		break;
+	case BPF_FUNC_get_local_storage:
+		/* check that flags argument in get_local_storage(map, flags) is 0,
+		 * this is required because get_local_storage() can't return an error.
+		 */
+		if (!register_is_null(&regs[BPF_REG_2])) {
+			verbose(env, "get_local_storage() doesn't support non-zero flags\n");
+			return -EINVAL;
+		}
+		break;
+	case BPF_FUNC_for_each_map_elem:
+		err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+					 set_map_elem_callback_state);
+		break;
+	case BPF_FUNC_timer_set_callback:
+		err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+					 set_timer_callback_state);
+		break;
+	case BPF_FUNC_find_vma:
+		err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+					 set_find_vma_callback_state);
+		break;
+	case BPF_FUNC_snprintf:
+		err = check_bpf_snprintf_call(env, regs);
+		break;
+	case BPF_FUNC_loop:
+		update_loop_inline_state(env, meta.subprogno);
+		/* Verifier relies on R1 value to determine if bpf_loop() iteration
+		 * is finished, thus mark it precise.
+		 */
+		err = mark_chain_precision(env, BPF_REG_1);
+		if (err)
+			return err;
+		if (cur_func(env)->callback_depth < regs[BPF_REG_1].umax_value) {
+			err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+						 set_loop_callback_state);
+		} else {
+			cur_func(env)->callback_depth = 0;
+			if (env->log.level & BPF_LOG_LEVEL2)
+				verbose(env, "frame%d bpf_loop iteration limit reached\n",
+					env->cur_state->curframe);
+		}
+		break;
+	case BPF_FUNC_dynptr_from_mem:
+		if (regs[BPF_REG_1].type != PTR_TO_MAP_VALUE) {
+			verbose(env, "Unsupported reg type %s for bpf_dynptr_from_mem data\n",
+				reg_type_str(env, regs[BPF_REG_1].type));
+			return -EACCES;
+		}
+		break;
+	case BPF_FUNC_set_retval:
+		if (prog_type == BPF_PROG_TYPE_LSM &&
+		    env->prog->expected_attach_type == BPF_LSM_CGROUP) {
+			if (!env->prog->aux->attach_func_proto->type) {
+				/* Make sure programs that attach to void
+				 * hooks don't try to modify return value.
+				 */
+				verbose(env, "BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
+				return -EINVAL;
+			}
+		}
+		break;
+	case BPF_FUNC_dynptr_data:
+	{
+		struct bpf_reg_state *reg;
+		int id, ref_obj_id;
+
+		reg = get_dynptr_arg_reg(env, fn, regs);
+		if (!reg)
+			return -EFAULT;
+
+
+		if (meta.dynptr_id) {
+			verbose(env, "verifier internal error: meta.dynptr_id already set\n");
+			return -EFAULT;
+		}
+		if (meta.ref_obj_id) {
+			verbose(env, "verifier internal error: meta.ref_obj_id already set\n");
+			return -EFAULT;
+		}
+
+		id = dynptr_id(env, reg);
+		if (id < 0) {
+			verbose(env, "verifier internal error: failed to obtain dynptr id\n");
+			return id;
+		}
+
+		ref_obj_id = dynptr_ref_obj_id(env, reg);
+		if (ref_obj_id < 0) {
+			verbose(env, "verifier internal error: failed to obtain dynptr ref_obj_id\n");
+			return ref_obj_id;
+		}
+
+		meta.dynptr_id = id;
+		meta.ref_obj_id = ref_obj_id;
+
+		break;
+	}
+	case BPF_FUNC_dynptr_write:
+	{
+		enum bpf_dynptr_type dynptr_type;
+		struct bpf_reg_state *reg;
+
+		reg = get_dynptr_arg_reg(env, fn, regs);
+		if (!reg)
+			return -EFAULT;
+
+		dynptr_type = dynptr_get_type(env, reg);
+		if (dynptr_type == BPF_DYNPTR_TYPE_INVALID)
+			return -EFAULT;
+
+		if (dynptr_type == BPF_DYNPTR_TYPE_SKB)
+			/* this will trigger clear_all_pkt_pointers(), which will
+			 * invalidate all dynptr slices associated with the skb
+			 */
+			changes_data = true;
+
+		break;
+	}
+	case BPF_FUNC_user_ringbuf_drain:
+		err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+					 set_user_ringbuf_callback_state);
+		break;
+	}
+
+	if (err)
+		return err;
+
+	/* reset caller saved regs */
+	for (i = 0; i < CALLER_SAVED_REGS; i++) {
+		mark_reg_not_init(env, regs, caller_saved[i]);
+		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+	}
+
+	/* helper call returns 64-bit value. */
+	regs[BPF_REG_0].subreg_def = DEF_NOT_SUBREG;
+
+	/* update return register (already marked as written above) */
+	ret_type = fn->ret_type;
+	ret_flag = type_flag(ret_type);
+
+	switch (base_type(ret_type)) {
+	case RET_INTEGER:
+		/* sets type to SCALAR_VALUE */
+		mark_reg_unknown(env, regs, BPF_REG_0);
+		break;
+	case RET_VOID:
+		regs[BPF_REG_0].type = NOT_INIT;
+		break;
+	case RET_PTR_TO_MAP_VALUE:
+		/* There is no offset yet applied, variable or fixed */
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		/* remember map_ptr, so that check_map_access()
+		 * can check 'value_size' boundary of memory access
+		 * to map element returned from bpf_map_lookup_elem()
+		 */
+		if (meta.map_ptr == NULL) {
+			verbose(env,
+				"kernel subsystem misconfigured verifier\n");
+			return -EINVAL;
+		}
+		regs[BPF_REG_0].map_ptr = meta.map_ptr;
+		regs[BPF_REG_0].map_uid = meta.map_uid;
+		regs[BPF_REG_0].type = PTR_TO_MAP_VALUE | ret_flag;
+		if (!type_may_be_null(ret_type) &&
+		    btf_record_has_field(meta.map_ptr->record, BPF_SPIN_LOCK)) {
+			regs[BPF_REG_0].id = ++env->id_gen;
+		}
+		break;
+	case RET_PTR_TO_SOCKET:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_SOCKET | ret_flag;
+		break;
+	case RET_PTR_TO_SOCK_COMMON:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_SOCK_COMMON | ret_flag;
+		break;
+	case RET_PTR_TO_TCP_SOCK:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_TCP_SOCK | ret_flag;
+		break;
+	case RET_PTR_TO_MEM:
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
+		regs[BPF_REG_0].mem_size = meta.mem_size;
+		break;
+	case RET_PTR_TO_MEM_OR_BTF_ID:
+	{
+		const struct btf_type *t;
+
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		t = btf_type_skip_modifiers(meta.ret_btf, meta.ret_btf_id, NULL);
+		if (!btf_type_is_struct(t)) {
+			u32 tsize;
+			const struct btf_type *ret;
+			const char *tname;
+
+			/* resolve the type size of ksym. */
+			ret = btf_resolve_size(meta.ret_btf, t, &tsize);
+			if (IS_ERR(ret)) {
+				tname = btf_name_by_offset(meta.ret_btf, t->name_off);
+				verbose(env, "unable to resolve the size of type '%s': %ld\n",
+					tname, PTR_ERR(ret));
+				return -EINVAL;
+			}
+			regs[BPF_REG_0].type = PTR_TO_MEM | ret_flag;
+			regs[BPF_REG_0].mem_size = tsize;
+		} else {
+			/* MEM_RDONLY may be carried from ret_flag, but it
+			 * doesn't apply on PTR_TO_BTF_ID. Fold it, otherwise
+			 * it will confuse the check of PTR_TO_BTF_ID in
+			 * check_mem_access().
+			 */
+			ret_flag &= ~MEM_RDONLY;
+
+			regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
+			regs[BPF_REG_0].btf = meta.ret_btf;
+			regs[BPF_REG_0].btf_id = meta.ret_btf_id;
+		}
+		break;
+	}
+	case RET_PTR_TO_BTF_ID:
+	{
+		struct btf *ret_btf;
+		int ret_btf_id;
+
+		mark_reg_known_zero(env, regs, BPF_REG_0);
+		regs[BPF_REG_0].type = PTR_TO_BTF_ID | ret_flag;
+		if (func_id == BPF_FUNC_kptr_xchg) {
+			ret_btf = meta.kptr_field->kptr.btf;
+			ret_btf_id = meta.kptr_field->kptr.btf_id;
+			if (!btf_is_kernel(ret_btf))
+				regs[BPF_REG_0].type |= MEM_ALLOC;
+		} else {
+			if (fn->ret_btf_id == BPF_PTR_POISON) {
+				verbose(env, "verifier internal error:");
+				verbose(env, "func %s has non-overwritten BPF_PTR_POISON return type\n",
+					func_id_name(func_id));
+				return -EINVAL;
+			}
+			ret_btf = btf_vmlinux;
+			ret_btf_id = *fn->ret_btf_id;
+		}
+		if (ret_btf_id == 0) {
+			verbose(env, "invalid return type %u of func %s#%d\n",
+				base_type(ret_type), func_id_name(func_id),
+				func_id);
+			return -EINVAL;
+		}
+		regs[BPF_REG_0].btf = ret_btf;
+		regs[BPF_REG_0].btf_id = ret_btf_id;
+		break;
+	}
+	default:
+		verbose(env, "unknown return type %u of func %s#%d\n",
+			base_type(ret_type), func_id_name(func_id), func_id);
+		return -EINVAL;
+	}
+
+	if (type_may_be_null(regs[BPF_REG_0].type))
+		regs[BPF_REG_0].id = ++env->id_gen;
+
+	if (helper_multiple_ref_obj_use(func_id, meta.map_ptr)) {
+		verbose(env, "verifier internal error: func %s#%d sets ref_obj_id more than once\n",
+			func_id_name(func_id), func_id);
+		return -EFAULT;
+	}
+
+	if (is_dynptr_ref_function(func_id))
+		regs[BPF_REG_0].dynptr_id = meta.dynptr_id;
+
+	if (is_ptr_cast_function(func_id) || is_dynptr_ref_function(func_id)) {
+		/* For release_reference() */
+		regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+	} else if (is_acquire_function(func_id, meta.map_ptr)) {
+		int id = acquire_reference_state(env, insn_idx);
+
+		if (id < 0)
+			return id;
+		/* For mark_ptr_or_null_reg() */
+		regs[BPF_REG_0].id = id;
+		/* For release_reference() */
+		regs[BPF_REG_0].ref_obj_id = id;
+	}
+
+	do_refine_retval_range(regs, fn->ret_type, func_id, &meta);
+
+	err = check_map_func_compatibility(env, meta.map_ptr, func_id);
+	if (err)
+		return err;
+
+	if ((func_id == BPF_FUNC_get_stack ||
+	     func_id == BPF_FUNC_get_task_stack) &&
+	    !env->prog->has_callchain_buf) {
+		const char *err_str;
+
+#ifdef CONFIG_PERF_EVENTS
+		err = get_callchain_buffers(sysctl_perf_event_max_stack);
+		err_str = "cannot get callchain buffer for func %s#%d\n";
+#else
+		err = -ENOTSUPP;
+		err_str = "func %s#%d not supported without CONFIG_PERF_EVENTS\n";
+#endif
+		if (err) {
+			verbose(env, err_str, func_id_name(func_id), func_id);
+			return err;
+		}
+
+		env->prog->has_callchain_buf = true;
+	}
+
+	if (func_id == BPF_FUNC_get_stackid || func_id == BPF_FUNC_get_stack)
+		env->prog->call_get_stack = true;
+
+	if (func_id == BPF_FUNC_get_func_ip) {
+		if (check_get_func_ip(env))
+			return -ENOTSUPP;
+		env->prog->call_get_func_ip = true;
+	}
+
+	if (changes_data)
+		clear_all_pkt_pointers(env);
+	return 0;
+}
+
+/* mark_btf_func_reg_size() is used when the reg size is determined by
+ * the BTF func_proto's return value size and argument.
+ */
+static void mark_btf_func_reg_size(struct bpf_verifier_env *env, u32 regno,
+				   size_t reg_size)
+{
+	struct bpf_reg_state *reg = &cur_regs(env)[regno];
+
+	if (regno == BPF_REG_0) {
+		/* Function return value */
+		reg->live |= REG_LIVE_WRITTEN;
+		reg->subreg_def = reg_size == sizeof(u64) ?
+			DEF_NOT_SUBREG : env->insn_idx + 1;
+	} else {
+		/* Function argument */
+		if (reg_size == sizeof(u64)) {
+			mark_insn_zext(env, reg);
+			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ64);
+		} else {
+			mark_reg_read(env, reg, reg->parent, REG_LIVE_READ32);
+		}
+	}
+}
+
+static bool is_kfunc_acquire(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_ACQUIRE;
+}
+
+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) || is_kfunc_release(meta);
+}
+
+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_rcu(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->kfunc_flags & KF_RCU;
+}
+
+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_const_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, "__szk");
+}
+
+static bool is_kfunc_arg_optional(const struct btf *btf, const struct btf_param *arg)
+{
+	return __kfunc_param_match_suffix(btf, arg, "__opt");
+}
+
+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_uninit(const struct btf *btf, const struct btf_param *arg)
+{
+	return __kfunc_param_match_suffix(btf, arg, "__uninit");
+}
+
+static bool is_kfunc_arg_refcounted_kptr(const struct btf *btf, const struct btf_param *arg)
+{
+	return __kfunc_param_match_suffix(btf, arg, "__refcounted_kptr");
+}
+
+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,
+	KF_ARG_RB_ROOT_ID,
+	KF_ARG_RB_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)
+BTF_ID(struct, bpf_rb_root)
+BTF_ID(struct, bpf_rb_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);
+}
+
+static bool is_kfunc_arg_rbtree_root(const struct btf *btf, const struct btf_param *arg)
+{
+	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_ROOT_ID);
+}
+
+static bool is_kfunc_arg_rbtree_node(const struct btf *btf, const struct btf_param *arg)
+{
+	return __is_kfunc_ptr_arg_type(btf, arg, KF_ARG_RB_NODE_ID);
+}
+
+static bool is_kfunc_arg_callback(struct bpf_verifier_env *env, const struct btf *btf,
+				  const struct btf_param *arg)
+{
+	const struct btf_type *t;
+
+	t = btf_type_resolve_func_ptr(btf, arg->type, NULL);
+	if (!t)
+		return false;
+
+	return true;
+}
+
+/* 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;
+}
+
+enum kfunc_ptr_arg_type {
+	KF_ARG_PTR_TO_CTX,
+	KF_ARG_PTR_TO_ALLOC_BTF_ID,    /* Allocated object */
+	KF_ARG_PTR_TO_REFCOUNTED_KPTR, /* Refcounted local kptr */
+	KF_ARG_PTR_TO_DYNPTR,
+	KF_ARG_PTR_TO_ITER,
+	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 */
+	KF_ARG_PTR_TO_CALLBACK,
+	KF_ARG_PTR_TO_RB_ROOT,
+	KF_ARG_PTR_TO_RB_NODE,
+};
+
+enum special_kfunc_type {
+	KF_bpf_obj_new_impl,
+	KF_bpf_obj_drop_impl,
+	KF_bpf_refcount_acquire_impl,
+	KF_bpf_list_push_front_impl,
+	KF_bpf_list_push_back_impl,
+	KF_bpf_list_pop_front,
+	KF_bpf_list_pop_back,
+	KF_bpf_cast_to_kern_ctx,
+	KF_bpf_rdonly_cast,
+	KF_bpf_rcu_read_lock,
+	KF_bpf_rcu_read_unlock,
+	KF_bpf_rbtree_remove,
+	KF_bpf_rbtree_add_impl,
+	KF_bpf_rbtree_first,
+	KF_bpf_dynptr_from_skb,
+	KF_bpf_dynptr_from_xdp,
+	KF_bpf_dynptr_slice,
+	KF_bpf_dynptr_slice_rdwr,
+	KF_bpf_dynptr_clone,
+};
+
+BTF_SET_START(special_kfunc_set)
+BTF_ID(func, bpf_obj_new_impl)
+BTF_ID(func, bpf_obj_drop_impl)
+BTF_ID(func, bpf_refcount_acquire_impl)
+BTF_ID(func, bpf_list_push_front_impl)
+BTF_ID(func, bpf_list_push_back_impl)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+BTF_ID(func, bpf_cast_to_kern_ctx)
+BTF_ID(func, bpf_rdonly_cast)
+BTF_ID(func, bpf_rbtree_remove)
+BTF_ID(func, bpf_rbtree_add_impl)
+BTF_ID(func, bpf_rbtree_first)
+BTF_ID(func, bpf_dynptr_from_skb)
+BTF_ID(func, bpf_dynptr_from_xdp)
+BTF_ID(func, bpf_dynptr_slice)
+BTF_ID(func, bpf_dynptr_slice_rdwr)
+BTF_ID(func, bpf_dynptr_clone)
+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_refcount_acquire_impl)
+BTF_ID(func, bpf_list_push_front_impl)
+BTF_ID(func, bpf_list_push_back_impl)
+BTF_ID(func, bpf_list_pop_front)
+BTF_ID(func, bpf_list_pop_back)
+BTF_ID(func, bpf_cast_to_kern_ctx)
+BTF_ID(func, bpf_rdonly_cast)
+BTF_ID(func, bpf_rcu_read_lock)
+BTF_ID(func, bpf_rcu_read_unlock)
+BTF_ID(func, bpf_rbtree_remove)
+BTF_ID(func, bpf_rbtree_add_impl)
+BTF_ID(func, bpf_rbtree_first)
+BTF_ID(func, bpf_dynptr_from_skb)
+BTF_ID(func, bpf_dynptr_from_xdp)
+BTF_ID(func, bpf_dynptr_slice)
+BTF_ID(func, bpf_dynptr_slice_rdwr)
+BTF_ID(func, bpf_dynptr_clone)
+
+static bool is_kfunc_ret_null(struct bpf_kfunc_call_arg_meta *meta)
+{
+	if (meta->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
+	    meta->arg_owning_ref) {
+		return false;
+	}
+
+	return meta->kfunc_flags & KF_RET_NULL;
+}
+
+static bool is_kfunc_bpf_rcu_read_lock(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_lock];
+}
+
+static bool is_kfunc_bpf_rcu_read_unlock(struct bpf_kfunc_call_arg_meta *meta)
+{
+	return meta->func_id == special_kfunc_list[KF_bpf_rcu_read_unlock];
+}
+
+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;
+
+	if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx])
+		return KF_ARG_PTR_TO_CTX;
+
+	/* 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_refcounted_kptr(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_REFCOUNTED_KPTR;
+
+	if (is_kfunc_arg_dynptr(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_DYNPTR;
+
+	if (is_kfunc_arg_iter(meta, argno))
+		return KF_ARG_PTR_TO_ITER;
+
+	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 (is_kfunc_arg_rbtree_root(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_RB_ROOT;
+
+	if (is_kfunc_arg_rbtree_node(meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_RB_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 (is_kfunc_arg_callback(env, meta->btf, &args[argno]))
+		return KF_ARG_PTR_TO_CALLBACK;
+
+
+	if (argno + 1 < nargs &&
+	    (is_kfunc_arg_mem_size(meta->btf, &args[argno + 1], &regs[regno + 1]) ||
+	     is_kfunc_arg_const_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 (base_type(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)];
+	}
+
+	/* Enforce strict type matching for calls to kfuncs that are acquiring
+	 * or releasing a reference, or are no-cast aliases. We do _not_
+	 * enforce strict matching for plain KF_TRUSTED_ARGS kfuncs by default,
+	 * as we want to enable BPF programs to pass types that are bitwise
+	 * equivalent without forcing them to explicitly cast with something
+	 * like bpf_cast_to_kern_ctx().
+	 *
+	 * For example, say we had a type like the following:
+	 *
+	 * struct bpf_cpumask {
+	 *	cpumask_t cpumask;
+	 *	refcount_t usage;
+	 * };
+	 *
+	 * Note that as specified in <linux/cpumask.h>, cpumask_t is typedef'ed
+	 * to a struct cpumask, so it would be safe to pass a struct
+	 * bpf_cpumask * to a kfunc expecting a struct cpumask *.
+	 *
+	 * The philosophy here is similar to how we allow scalars of different
+	 * types to be passed to kfuncs as long as the size is the same. The
+	 * only difference here is that we're simply allowing
+	 * btf_struct_ids_match() to walk the struct at the 0th offset, and
+	 * resolve types.
+	 */
+	if (is_kfunc_acquire(meta) ||
+	    (is_kfunc_release(meta) && reg->ref_obj_id) ||
+	    btf_type_ids_nocast_alias(&env->log, reg_btf, reg_ref_id, meta->btf, ref_id))
+		strict_type_match = true;
+
+	WARN_ON_ONCE(is_kfunc_trusted_args(meta) && reg->off);
+
+	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 ref_set_non_owning(struct bpf_verifier_env *env, struct bpf_reg_state *reg)
+{
+	struct bpf_verifier_state *state = env->cur_state;
+	struct btf_record *rec = reg_btf_record(reg);
+
+	if (!state->active_lock.ptr) {
+		verbose(env, "verifier internal error: ref_set_non_owning w/o active lock\n");
+		return -EFAULT;
+	}
+
+	if (type_flag(reg->type) & NON_OWN_REF) {
+		verbose(env, "verifier internal error: NON_OWN_REF already set\n");
+		return -EFAULT;
+	}
+
+	reg->type |= NON_OWN_REF;
+	if (rec->refcount_off >= 0)
+		reg->type |= MEM_RCU;
+
+	return 0;
+}
+
+static int ref_convert_owning_non_owning(struct bpf_verifier_env *env, u32 ref_obj_id)
+{
+	struct bpf_func_state *state, *unused;
+	struct bpf_reg_state *reg;
+	int i;
+
+	state = cur_func(env);
+
+	if (!ref_obj_id) {
+		verbose(env, "verifier internal error: ref_obj_id is zero for "
+			     "owning -> non-owning conversion\n");
+		return -EFAULT;
+	}
+
+	for (i = 0; i < state->acquired_refs; i++) {
+		if (state->refs[i].id != ref_obj_id)
+			continue;
+
+		/* Clear ref_obj_id here so release_reference doesn't clobber
+		 * the whole reg
+		 */
+		bpf_for_each_reg_in_vstate(env->cur_state, unused, reg, ({
+			if (reg->ref_obj_id == ref_obj_id) {
+				reg->ref_obj_id = 0;
+				ref_set_non_owning(env, reg);
+			}
+		}));
+		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_impl] ||
+	       btf_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+	       btf_id == special_kfunc_list[KF_bpf_list_pop_front] ||
+	       btf_id == special_kfunc_list[KF_bpf_list_pop_back];
+}
+
+static bool is_bpf_rbtree_api_kfunc(u32 btf_id)
+{
+	return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl] ||
+	       btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
+	       btf_id == special_kfunc_list[KF_bpf_rbtree_first];
+}
+
+static bool is_bpf_graph_api_kfunc(u32 btf_id)
+{
+	return is_bpf_list_api_kfunc(btf_id) || is_bpf_rbtree_api_kfunc(btf_id) ||
+	       btf_id == special_kfunc_list[KF_bpf_refcount_acquire_impl];
+}
+
+static bool is_sync_callback_calling_kfunc(u32 btf_id)
+{
+	return btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl];
+}
+
+static bool is_rbtree_lock_required_kfunc(u32 btf_id)
+{
+	return is_bpf_rbtree_api_kfunc(btf_id);
+}
+
+static bool check_kfunc_is_graph_root_api(struct bpf_verifier_env *env,
+					  enum btf_field_type head_field_type,
+					  u32 kfunc_btf_id)
+{
+	bool ret;
+
+	switch (head_field_type) {
+	case BPF_LIST_HEAD:
+		ret = is_bpf_list_api_kfunc(kfunc_btf_id);
+		break;
+	case BPF_RB_ROOT:
+		ret = is_bpf_rbtree_api_kfunc(kfunc_btf_id);
+		break;
+	default:
+		verbose(env, "verifier internal error: unexpected graph root argument type %s\n",
+			btf_field_type_name(head_field_type));
+		return false;
+	}
+
+	if (!ret)
+		verbose(env, "verifier internal error: %s head arg for unknown kfunc\n",
+			btf_field_type_name(head_field_type));
+	return ret;
+}
+
+static bool check_kfunc_is_graph_node_api(struct bpf_verifier_env *env,
+					  enum btf_field_type node_field_type,
+					  u32 kfunc_btf_id)
+{
+	bool ret;
+
+	switch (node_field_type) {
+	case BPF_LIST_NODE:
+		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+		       kfunc_btf_id == special_kfunc_list[KF_bpf_list_push_back_impl]);
+		break;
+	case BPF_RB_NODE:
+		ret = (kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
+		       kfunc_btf_id == special_kfunc_list[KF_bpf_rbtree_add_impl]);
+		break;
+	default:
+		verbose(env, "verifier internal error: unexpected graph node argument type %s\n",
+			btf_field_type_name(node_field_type));
+		return false;
+	}
+
+	if (!ret)
+		verbose(env, "verifier internal error: %s node arg for unknown kfunc\n",
+			btf_field_type_name(node_field_type));
+	return ret;
+}
+
+static int
+__process_kf_arg_ptr_to_graph_root(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *reg, u32 regno,
+				   struct bpf_kfunc_call_arg_meta *meta,
+				   enum btf_field_type head_field_type,
+				   struct btf_field **head_field)
+{
+	const char *head_type_name;
+	struct btf_field *field;
+	struct btf_record *rec;
+	u32 head_off;
+
+	if (meta->btf != btf_vmlinux) {
+		verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
+		return -EFAULT;
+	}
+
+	if (!check_kfunc_is_graph_root_api(env, head_field_type, meta->func_id))
+		return -EFAULT;
+
+	head_type_name = btf_field_type_name(head_field_type);
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env,
+			"R%d doesn't have constant offset. %s has to be at the constant offset\n",
+			regno, head_type_name);
+		return -EINVAL;
+	}
+
+	rec = reg_btf_record(reg);
+	head_off = reg->off + reg->var_off.value;
+	field = btf_record_find(rec, head_off, head_field_type);
+	if (!field) {
+		verbose(env, "%s not found at offset=%u\n", head_type_name, 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 %s\n",
+			rec->spin_lock_off, head_type_name);
+		return -EINVAL;
+	}
+
+	if (*head_field) {
+		verbose(env, "verifier internal error: repeating %s arg\n", head_type_name);
+		return -EFAULT;
+	}
+	*head_field = field;
+	return 0;
+}
+
+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)
+{
+	return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_LIST_HEAD,
+							  &meta->arg_list_head.field);
+}
+
+static int process_kf_arg_ptr_to_rbtree_root(struct bpf_verifier_env *env,
+					     struct bpf_reg_state *reg, u32 regno,
+					     struct bpf_kfunc_call_arg_meta *meta)
+{
+	return __process_kf_arg_ptr_to_graph_root(env, reg, regno, meta, BPF_RB_ROOT,
+							  &meta->arg_rbtree_root.field);
+}
+
+static int
+__process_kf_arg_ptr_to_graph_node(struct bpf_verifier_env *env,
+				   struct bpf_reg_state *reg, u32 regno,
+				   struct bpf_kfunc_call_arg_meta *meta,
+				   enum btf_field_type head_field_type,
+				   enum btf_field_type node_field_type,
+				   struct btf_field **node_field)
+{
+	const char *node_type_name;
+	const struct btf_type *et, *t;
+	struct btf_field *field;
+	u32 node_off;
+
+	if (meta->btf != btf_vmlinux) {
+		verbose(env, "verifier internal error: unexpected btf mismatch in kfunc call\n");
+		return -EFAULT;
+	}
+
+	if (!check_kfunc_is_graph_node_api(env, node_field_type, meta->func_id))
+		return -EFAULT;
+
+	node_type_name = btf_field_type_name(node_field_type);
+	if (!tnum_is_const(reg->var_off)) {
+		verbose(env,
+			"R%d doesn't have constant offset. %s has to be at the constant offset\n",
+			regno, node_type_name);
+		return -EINVAL;
+	}
+
+	node_off = reg->off + reg->var_off.value;
+	field = reg_find_field_offset(reg, node_off, node_field_type);
+	if (!field || field->offset != node_off) {
+		verbose(env, "%s not found at offset=%u\n", node_type_name, node_off);
+		return -EINVAL;
+	}
+
+	field = *node_field;
+
+	et = btf_type_by_id(field->graph_root.btf, field->graph_root.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->graph_root.btf,
+				  field->graph_root.value_btf_id, true)) {
+		verbose(env, "operation on %s expects arg#1 %s at offset=%d "
+			"in struct %s, but arg is at offset=%d in struct %s\n",
+			btf_field_type_name(head_field_type),
+			btf_field_type_name(node_field_type),
+			field->graph_root.node_offset,
+			btf_name_by_offset(field->graph_root.btf, et->name_off),
+			node_off, btf_name_by_offset(reg->btf, t->name_off));
+		return -EINVAL;
+	}
+	meta->arg_btf = reg->btf;
+	meta->arg_btf_id = reg->btf_id;
+
+	if (node_off != field->graph_root.node_offset) {
+		verbose(env, "arg#1 offset=%d, but expected %s at offset=%d in struct %s\n",
+			node_off, btf_field_type_name(node_field_type),
+			field->graph_root.node_offset,
+			btf_name_by_offset(field->graph_root.btf, et->name_off));
+		return -EINVAL;
+	}
+
+	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)
+{
+	return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
+						  BPF_LIST_HEAD, BPF_LIST_NODE,
+						  &meta->arg_list_head.field);
+}
+
+static int process_kf_arg_ptr_to_rbtree_node(struct bpf_verifier_env *env,
+					     struct bpf_reg_state *reg, u32 regno,
+					     struct bpf_kfunc_call_arg_meta *meta)
+{
+	return __process_kf_arg_ptr_to_graph_node(env, reg, regno, meta,
+						  BPF_RB_ROOT, BPF_RB_NODE,
+						  &meta->arg_rbtree_root.field);
+}
+
+static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_arg_meta *meta,
+			    int insn_idx)
+{
+	const char *func_name = meta->func_name, *ref_tname;
+	const struct btf *btf = meta->btf;
+	const struct btf_param *args;
+	struct btf_record *rec;
+	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 ((is_kfunc_trusted_args(meta) || is_kfunc_rcu(meta)) &&
+		    (register_is_null(reg) || type_may_be_null(reg->type))) {
+			verbose(env, "Possibly NULL pointer passed to trusted arg%d\n", i);
+			return -EACCES;
+		}
+
+		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) && !is_kfunc_rcu(meta))
+				break;
+
+			if (!is_trusted_reg(reg)) {
+				if (!is_kfunc_rcu(meta)) {
+					verbose(env, "R%d must be referenced or trusted\n", regno);
+					return -EINVAL;
+				}
+				if (!is_rcu_reg(reg)) {
+					verbose(env, "R%d must be a rcu pointer\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_DYNPTR:
+		case KF_ARG_PTR_TO_ITER:
+		case KF_ARG_PTR_TO_LIST_HEAD:
+		case KF_ARG_PTR_TO_LIST_NODE:
+		case KF_ARG_PTR_TO_RB_ROOT:
+		case KF_ARG_PTR_TO_RB_NODE:
+		case KF_ARG_PTR_TO_MEM:
+		case KF_ARG_PTR_TO_MEM_SIZE:
+		case KF_ARG_PTR_TO_CALLBACK:
+		case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
+			/* 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;
+			}
+
+			if (meta->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
+				ret = get_kern_ctx_btf_id(&env->log, resolve_prog_type(env->prog));
+				if (ret < 0)
+					return -EINVAL;
+				meta->ret_btf_id  = ret;
+			}
+			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_btf = reg->btf;
+				meta->arg_btf_id = reg->btf_id;
+			}
+			break;
+		case KF_ARG_PTR_TO_DYNPTR:
+		{
+			enum bpf_arg_type dynptr_arg_type = ARG_PTR_TO_DYNPTR;
+			int clone_ref_obj_id = 0;
+
+			if (reg->type != PTR_TO_STACK &&
+			    reg->type != CONST_PTR_TO_DYNPTR) {
+				verbose(env, "arg#%d expected pointer to stack or dynptr_ptr\n", i);
+				return -EINVAL;
+			}
+
+			if (reg->type == CONST_PTR_TO_DYNPTR)
+				dynptr_arg_type |= MEM_RDONLY;
+
+			if (is_kfunc_arg_uninit(btf, &args[i]))
+				dynptr_arg_type |= MEM_UNINIT;
+
+			if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) {
+				dynptr_arg_type |= DYNPTR_TYPE_SKB;
+			} else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_from_xdp]) {
+				dynptr_arg_type |= DYNPTR_TYPE_XDP;
+			} else if (meta->func_id == special_kfunc_list[KF_bpf_dynptr_clone] &&
+				   (dynptr_arg_type & MEM_UNINIT)) {
+				enum bpf_dynptr_type parent_type = meta->initialized_dynptr.type;
+
+				if (parent_type == BPF_DYNPTR_TYPE_INVALID) {
+					verbose(env, "verifier internal error: no dynptr type for parent of clone\n");
+					return -EFAULT;
+				}
+
+				dynptr_arg_type |= (unsigned int)get_dynptr_type_flag(parent_type);
+				clone_ref_obj_id = meta->initialized_dynptr.ref_obj_id;
+				if (dynptr_type_refcounted(parent_type) && !clone_ref_obj_id) {
+					verbose(env, "verifier internal error: missing ref obj id for parent of clone\n");
+					return -EFAULT;
+				}
+			}
+
+			ret = process_dynptr_func(env, regno, insn_idx, dynptr_arg_type, clone_ref_obj_id);
+			if (ret < 0)
+				return ret;
+
+			if (!(dynptr_arg_type & MEM_UNINIT)) {
+				int id = dynptr_id(env, reg);
+
+				if (id < 0) {
+					verbose(env, "verifier internal error: failed to obtain dynptr id\n");
+					return id;
+				}
+				meta->initialized_dynptr.id = id;
+				meta->initialized_dynptr.type = dynptr_get_type(env, reg);
+				meta->initialized_dynptr.ref_obj_id = dynptr_ref_obj_id(env, reg);
+			}
+
+			break;
+		}
+		case KF_ARG_PTR_TO_ITER:
+			ret = process_iter_arg(env, regno, insn_idx, meta);
+			if (ret < 0)
+				return ret;
+			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_RB_ROOT:
+			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_rbtree_root(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_RB_NODE:
+			if (meta->func_id == special_kfunc_list[KF_bpf_rbtree_remove]) {
+				if (!type_is_non_owning_ref(reg->type) || reg->ref_obj_id) {
+					verbose(env, "rbtree_remove node input must be non-owning ref\n");
+					return -EINVAL;
+				}
+				if (in_rbtree_lock_required_cb(env)) {
+					verbose(env, "rbtree_remove not allowed in rbtree cb\n");
+					return -EINVAL;
+				}
+			} else {
+				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_rbtree_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 ((base_type(reg->type) != PTR_TO_BTF_ID ||
+			     (bpf_type_has_unsafe_modifiers(reg->type) && !is_rcu_reg(reg))) &&
+			    !reg2btf_ids[base_type(reg->type)]) {
+				verbose(env, "arg#%d is %s ", i, reg_type_str(env, reg->type));
+				verbose(env, "expected %s or socket\n",
+					reg_type_str(env, base_type(reg->type) |
+							  (type_flag(reg->type) & BPF_REG_TRUSTED_MODIFIERS)));
+				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:
+		{
+			struct bpf_reg_state *buff_reg = &regs[regno];
+			const struct btf_param *buff_arg = &args[i];
+			struct bpf_reg_state *size_reg = &regs[regno + 1];
+			const struct btf_param *size_arg = &args[i + 1];
+
+			if (!register_is_null(buff_reg) || !is_kfunc_arg_optional(meta->btf, buff_arg)) {
+				ret = check_kfunc_mem_size_reg(env, size_reg, 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;
+				}
+			}
+
+			if (is_kfunc_arg_const_mem_size(meta->btf, size_arg, size_reg)) {
+				if (meta->arg_constant.found) {
+					verbose(env, "verifier internal error: only one constant argument permitted\n");
+					return -EFAULT;
+				}
+				if (!tnum_is_const(size_reg->var_off)) {
+					verbose(env, "R%d must be a known constant\n", regno + 1);
+					return -EINVAL;
+				}
+				meta->arg_constant.found = true;
+				meta->arg_constant.value = size_reg->var_off.value;
+			}
+
+			/* Skip next '__sz' or '__szk' argument */
+			i++;
+			break;
+		}
+		case KF_ARG_PTR_TO_CALLBACK:
+			if (reg->type != PTR_TO_FUNC) {
+				verbose(env, "arg%d expected pointer to func\n", i);
+				return -EINVAL;
+			}
+			meta->subprogno = reg->subprogno;
+			break;
+		case KF_ARG_PTR_TO_REFCOUNTED_KPTR:
+			if (!type_is_ptr_alloc_obj(reg->type)) {
+				verbose(env, "arg#%d is neither owning or non-owning ref\n", i);
+				return -EINVAL;
+			}
+			if (!type_is_non_owning_ref(reg->type))
+				meta->arg_owning_ref = true;
+
+			rec = reg_btf_record(reg);
+			if (!rec) {
+				verbose(env, "verifier internal error: Couldn't find btf_record\n");
+				return -EFAULT;
+			}
+
+			if (rec->refcount_off < 0) {
+				verbose(env, "arg#%d doesn't point to a type with bpf_refcount field\n", i);
+				return -EINVAL;
+			}
+
+			meta->arg_btf = reg->btf;
+			meta->arg_btf_id = reg->btf_id;
+			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 fetch_kfunc_meta(struct bpf_verifier_env *env,
+			    struct bpf_insn *insn,
+			    struct bpf_kfunc_call_arg_meta *meta,
+			    const char **kfunc_name)
+{
+	const struct btf_type *func, *func_proto;
+	u32 func_id, *kfunc_flags;
+	const char *func_name;
+	struct btf *desc_btf;
+
+	if (kfunc_name)
+		*kfunc_name = NULL;
+
+	if (!insn->imm)
+		return -EINVAL;
+
+	desc_btf = find_kfunc_desc_btf(env, insn->off);
+	if (IS_ERR(desc_btf))
+		return PTR_ERR(desc_btf);
+
+	func_id = insn->imm;
+	func = btf_type_by_id(desc_btf, func_id);
+	func_name = btf_name_by_offset(desc_btf, func->name_off);
+	if (kfunc_name)
+		*kfunc_name = func_name;
+	func_proto = btf_type_by_id(desc_btf, func->type);
+
+	kfunc_flags = btf_kfunc_id_set_contains(desc_btf, func_id, env->prog);
+	if (!kfunc_flags) {
+		return -EACCES;
+	}
+
+	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;
+
+	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, *ptr_type;
+	u32 i, nargs, ptr_type_id, release_ref_obj_id;
+	struct bpf_reg_state *regs = cur_regs(env);
+	const char *func_name, *ptr_type_name;
+	bool sleepable, rcu_lock, rcu_unlock;
+	struct bpf_kfunc_call_arg_meta meta;
+	struct bpf_insn_aux_data *insn_aux;
+	int err, insn_idx = *insn_idx_p;
+	const struct btf_param *args;
+	const struct btf_type *ret_t;
+	struct btf *desc_btf;
+
+	/* skip for now, but return error when we find this in fixup_kfunc_call */
+	if (!insn->imm)
+		return 0;
+
+	err = fetch_kfunc_meta(env, insn, &meta, &func_name);
+	if (err == -EACCES && func_name)
+		verbose(env, "calling kernel function %s is not allowed\n", func_name);
+	if (err)
+		return err;
+	desc_btf = meta.btf;
+	insn_aux = &env->insn_aux_data[insn_idx];
+
+	insn_aux->is_iter_next = is_iter_next_kfunc(&meta);
+
+	if (is_kfunc_destructive(&meta) && !capable(CAP_SYS_BOOT)) {
+		verbose(env, "destructive kfunc calls require CAP_SYS_BOOT capability\n");
+		return -EACCES;
+	}
+
+	sleepable = is_kfunc_sleepable(&meta);
+	if (sleepable && !env->prog->aux->sleepable) {
+		verbose(env, "program must be sleepable to call sleepable kfunc %s\n", func_name);
+		return -EACCES;
+	}
+
+	/* Check the arguments */
+	err = check_kfunc_args(env, &meta, insn_idx);
+	if (err < 0)
+		return err;
+
+	if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+		err = push_callback_call(env, insn, insn_idx, meta.subprogno,
+					 set_rbtree_add_callback_state);
+		if (err) {
+			verbose(env, "kfunc %s#%d failed callback verification\n",
+				func_name, meta.func_id);
+			return err;
+		}
+	}
+
+	rcu_lock = is_kfunc_bpf_rcu_read_lock(&meta);
+	rcu_unlock = is_kfunc_bpf_rcu_read_unlock(&meta);
+
+	if (env->cur_state->active_rcu_lock) {
+		struct bpf_func_state *state;
+		struct bpf_reg_state *reg;
+
+		if (in_rbtree_lock_required_cb(env) && (rcu_lock || rcu_unlock)) {
+			verbose(env, "Calling bpf_rcu_read_{lock,unlock} in unnecessary rbtree callback\n");
+			return -EACCES;
+		}
+
+		if (rcu_lock) {
+			verbose(env, "nested rcu read lock (kernel function %s)\n", func_name);
+			return -EINVAL;
+		} else if (rcu_unlock) {
+			bpf_for_each_reg_in_vstate(env->cur_state, state, reg, ({
+				if (reg->type & MEM_RCU) {
+					reg->type &= ~(MEM_RCU | PTR_MAYBE_NULL);
+					reg->type |= PTR_UNTRUSTED;
+				}
+			}));
+			env->cur_state->active_rcu_lock = false;
+		} else if (sleepable) {
+			verbose(env, "kernel func %s is sleepable within rcu_read_lock region\n", func_name);
+			return -EACCES;
+		}
+	} else if (rcu_lock) {
+		env->cur_state->active_rcu_lock = true;
+	} else if (rcu_unlock) {
+		verbose(env, "unmatched rcu read unlock (kernel function %s)\n", func_name);
+		return -EINVAL;
+	}
+
+	/* In case of release function, we get register number of refcounted
+	 * PTR_TO_BTF_ID in bpf_kfunc_arg_meta, do the release now.
+	 */
+	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, meta.func_id);
+			return err;
+		}
+	}
+
+	if (meta.func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+	    meta.func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+	    meta.func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+		release_ref_obj_id = regs[BPF_REG_2].ref_obj_id;
+		insn_aux->insert_off = regs[BPF_REG_2].off;
+		insn_aux->kptr_struct_meta = btf_find_struct_meta(meta.arg_btf, meta.arg_btf_id);
+		err = ref_convert_owning_non_owning(env, release_ref_obj_id);
+		if (err) {
+			verbose(env, "kfunc %s#%d conversion of owning ref to non-owning failed\n",
+				func_name, meta.func_id);
+			return err;
+		}
+
+		err = release_reference(env, release_ref_obj_id);
+		if (err) {
+			verbose(env, "kfunc %s#%d reference has not been acquired before\n",
+				func_name, meta.func_id);
+			return err;
+		}
+	}
+
+	for (i = 0; i < CALLER_SAVED_REGS; i++)
+		mark_reg_not_init(env, regs, caller_saved[i]);
+
+	/* Check return type */
+	t = btf_type_skip_modifiers(desc_btf, meta.func_proto->type, NULL);
+
+	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] &&
+		     meta.func_id != special_kfunc_list[KF_bpf_refcount_acquire_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 (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]) {
+				struct btf *ret_btf;
+				u32 ret_btf_id;
+
+				if (unlikely(!bpf_global_ma_set))
+					return -ENOMEM;
+
+				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;
+
+				insn_aux->obj_new_size = ret_t->size;
+				insn_aux->kptr_struct_meta =
+					btf_find_struct_meta(ret_btf, ret_btf_id);
+			} else if (meta.func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl]) {
+				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 = meta.arg_btf;
+				regs[BPF_REG_0].btf_id = meta.arg_btf_id;
+
+				insn_aux->kptr_struct_meta =
+					btf_find_struct_meta(meta.arg_btf,
+							     meta.arg_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_graph_node(regs, BPF_REG_0, &field->graph_root);
+			} else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_remove] ||
+				   meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
+				struct btf_field *field = meta.arg_rbtree_root.field;
+
+				mark_reg_graph_node(regs, BPF_REG_0, &field->graph_root);
+			} else if (meta.func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx]) {
+				mark_reg_known_zero(env, regs, BPF_REG_0);
+				regs[BPF_REG_0].type = PTR_TO_BTF_ID | PTR_TRUSTED;
+				regs[BPF_REG_0].btf = desc_btf;
+				regs[BPF_REG_0].btf_id = meta.ret_btf_id;
+			} else if (meta.func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
+				ret_t = btf_type_by_id(desc_btf, meta.arg_constant.value);
+				if (!ret_t || !btf_type_is_struct(ret_t)) {
+					verbose(env,
+						"kfunc bpf_rdonly_cast 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 | PTR_UNTRUSTED;
+				regs[BPF_REG_0].btf = desc_btf;
+				regs[BPF_REG_0].btf_id = meta.arg_constant.value;
+			} else if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice] ||
+				   meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice_rdwr]) {
+				enum bpf_type_flag type_flag = get_dynptr_type_flag(meta.initialized_dynptr.type);
+
+				mark_reg_known_zero(env, regs, BPF_REG_0);
+
+				if (!meta.arg_constant.found) {
+					verbose(env, "verifier internal error: bpf_dynptr_slice(_rdwr) no constant size\n");
+					return -EFAULT;
+				}
+
+				regs[BPF_REG_0].mem_size = meta.arg_constant.value;
+
+				/* PTR_MAYBE_NULL will be added when is_kfunc_ret_null is checked */
+				regs[BPF_REG_0].type = PTR_TO_MEM | type_flag;
+
+				if (meta.func_id == special_kfunc_list[KF_bpf_dynptr_slice]) {
+					regs[BPF_REG_0].type |= MEM_RDONLY;
+				} else {
+					/* this will set env->seen_direct_write to true */
+					if (!may_access_direct_pkt_data(env, NULL, BPF_WRITE)) {
+						verbose(env, "the prog does not allow writes to packet data\n");
+						return -EINVAL;
+					}
+				}
+
+				if (!meta.initialized_dynptr.id) {
+					verbose(env, "verifier internal error: no dynptr id\n");
+					return -EFAULT;
+				}
+				regs[BPF_REG_0].dynptr_id = meta.initialized_dynptr.id;
+
+				/* we don't need to set BPF_REG_0's ref obj id
+				 * because packet slices are not refcounted (see
+				 * dynptr_type_refcounted)
+				 */
+			} 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) {
+				__u32 sz;
+
+				if (!IS_ERR(btf_resolve_size(desc_btf, ptr_type, &sz))) {
+					meta.r0_size = sz;
+					meta.r0_rdonly = true;
+				}
+			}
+			if (!meta.r0_size) {
+				ptr_type_name = btf_name_by_offset(desc_btf,
+								   ptr_type->name_off);
+				verbose(env,
+					"kernel function %s returns pointer type %s %s is not supported\n",
+					func_name,
+					btf_type_str(ptr_type),
+					ptr_type_name);
+				return -EINVAL;
+			}
+
+			mark_reg_known_zero(env, regs, BPF_REG_0);
+			regs[BPF_REG_0].type = PTR_TO_MEM;
+			regs[BPF_REG_0].mem_size = meta.r0_size;
+
+			if (meta.r0_rdonly)
+				regs[BPF_REG_0].type |= MEM_RDONLY;
+
+			/* Ensures we don't access the memory after a release_reference() */
+			if (meta.ref_obj_id)
+				regs[BPF_REG_0].ref_obj_id = meta.ref_obj_id;
+		} else {
+			mark_reg_known_zero(env, regs, BPF_REG_0);
+			regs[BPF_REG_0].btf = desc_btf;
+			regs[BPF_REG_0].type = PTR_TO_BTF_ID;
+			regs[BPF_REG_0].btf_id = ptr_type_id;
+		}
+
+		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 (is_kfunc_acquire(&meta)) {
+			int id = acquire_reference_state(env, insn_idx);
+
+			if (id < 0)
+				return id;
+			if (is_kfunc_ret_null(&meta))
+				regs[BPF_REG_0].id = id;
+			regs[BPF_REG_0].ref_obj_id = id;
+		} else if (meta.func_id == special_kfunc_list[KF_bpf_rbtree_first]) {
+			ref_set_non_owning(env, &regs[BPF_REG_0]);
+		}
+
+		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 if (btf_type_is_void(t)) {
+		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_drop_impl]) {
+				insn_aux->kptr_struct_meta =
+					btf_find_struct_meta(meta.arg_btf,
+							     meta.arg_btf_id);
+			}
+		}
+	}
+
+	nargs = btf_type_vlen(meta.func_proto);
+	args = (const struct btf_param *)(meta.func_proto + 1);
+	for (i = 0; i < nargs; i++) {
+		u32 regno = i + 1;
+
+		t = btf_type_skip_modifiers(desc_btf, args[i].type, NULL);
+		if (btf_type_is_ptr(t))
+			mark_btf_func_reg_size(env, regno, sizeof(void *));
+		else
+			/* scalar. ensured by btf_check_kfunc_arg_match() */
+			mark_btf_func_reg_size(env, regno, t->size);
+	}
+
+	if (is_iter_next_kfunc(&meta)) {
+		err = process_iter_next_call(env, insn_idx, &meta);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static bool signed_add_overflows(s64 a, s64 b)
+{
+	/* Do the add in u64, where overflow is well-defined */
+	s64 res = (s64)((u64)a + (u64)b);
+
+	if (b < 0)
+		return res > a;
+	return res < a;
+}
+
+static bool signed_add32_overflows(s32 a, s32 b)
+{
+	/* Do the add in u32, where overflow is well-defined */
+	s32 res = (s32)((u32)a + (u32)b);
+
+	if (b < 0)
+		return res > a;
+	return res < a;
+}
+
+static bool signed_sub_overflows(s64 a, s64 b)
+{
+	/* Do the sub in u64, where overflow is well-defined */
+	s64 res = (s64)((u64)a - (u64)b);
+
+	if (b < 0)
+		return res < a;
+	return res > a;
+}
+
+static bool signed_sub32_overflows(s32 a, s32 b)
+{
+	/* Do the sub in u32, where overflow is well-defined */
+	s32 res = (s32)((u32)a - (u32)b);
+
+	if (b < 0)
+		return res < a;
+	return res > a;
+}
+
+static bool check_reg_sane_offset(struct bpf_verifier_env *env,
+				  const struct bpf_reg_state *reg,
+				  enum bpf_reg_type type)
+{
+	bool known = tnum_is_const(reg->var_off);
+	s64 val = reg->var_off.value;
+	s64 smin = reg->smin_value;
+
+	if (known && (val >= BPF_MAX_VAR_OFF || val <= -BPF_MAX_VAR_OFF)) {
+		verbose(env, "math between %s pointer and %lld is not allowed\n",
+			reg_type_str(env, type), val);
+		return false;
+	}
+
+	if (reg->off >= BPF_MAX_VAR_OFF || reg->off <= -BPF_MAX_VAR_OFF) {
+		verbose(env, "%s pointer offset %d is not allowed\n",
+			reg_type_str(env, type), reg->off);
+		return false;
+	}
+
+	if (smin == S64_MIN) {
+		verbose(env, "math between %s pointer and register with unbounded min value is not allowed\n",
+			reg_type_str(env, type));
+		return false;
+	}
+
+	if (smin >= BPF_MAX_VAR_OFF || smin <= -BPF_MAX_VAR_OFF) {
+		verbose(env, "value %lld makes %s pointer be out of bounds\n",
+			smin, reg_type_str(env, type));
+		return false;
+	}
+
+	return true;
+}
+
+enum {
+	REASON_BOUNDS	= -1,
+	REASON_TYPE	= -2,
+	REASON_PATHS	= -3,
+	REASON_LIMIT	= -4,
+	REASON_STACK	= -5,
+};
+
+static int retrieve_ptr_limit(const struct bpf_reg_state *ptr_reg,
+			      u32 *alu_limit, bool mask_to_left)
+{
+	u32 max = 0, ptr_limit = 0;
+
+	switch (ptr_reg->type) {
+	case PTR_TO_STACK:
+		/* Offset 0 is out-of-bounds, but acceptable start for the
+		 * left direction, see BPF_REG_FP. Also, unknown scalar
+		 * offset where we would need to deal with min/max bounds is
+		 * currently prohibited for unprivileged.
+		 */
+		max = MAX_BPF_STACK + mask_to_left;
+		ptr_limit = -(ptr_reg->var_off.value + ptr_reg->off);
+		break;
+	case PTR_TO_MAP_VALUE:
+		max = ptr_reg->map_ptr->value_size;
+		ptr_limit = (mask_to_left ?
+			     ptr_reg->smin_value :
+			     ptr_reg->umax_value) + ptr_reg->off;
+		break;
+	default:
+		return REASON_TYPE;
+	}
+
+	if (ptr_limit >= max)
+		return REASON_LIMIT;
+	*alu_limit = ptr_limit;
+	return 0;
+}
+
+static bool can_skip_alu_sanitation(const struct bpf_verifier_env *env,
+				    const struct bpf_insn *insn)
+{
+	return env->bypass_spec_v1 || BPF_SRC(insn->code) == BPF_K;
+}
+
+static int update_alu_sanitation_state(struct bpf_insn_aux_data *aux,
+				       u32 alu_state, u32 alu_limit)
+{
+	/* If we arrived here from different branches with different
+	 * state or limits to sanitize, then this won't work.
+	 */
+	if (aux->alu_state &&
+	    (aux->alu_state != alu_state ||
+	     aux->alu_limit != alu_limit))
+		return REASON_PATHS;
+
+	/* Corresponding fixup done in do_misc_fixups(). */
+	aux->alu_state = alu_state;
+	aux->alu_limit = alu_limit;
+	return 0;
+}
+
+static int sanitize_val_alu(struct bpf_verifier_env *env,
+			    struct bpf_insn *insn)
+{
+	struct bpf_insn_aux_data *aux = cur_aux(env);
+
+	if (can_skip_alu_sanitation(env, insn))
+		return 0;
+
+	return update_alu_sanitation_state(aux, BPF_ALU_NON_POINTER, 0);
+}
+
+static bool sanitize_needed(u8 opcode)
+{
+	return opcode == BPF_ADD || opcode == BPF_SUB;
+}
+
+struct bpf_sanitize_info {
+	struct bpf_insn_aux_data aux;
+	bool mask_to_left;
+};
+
+static struct bpf_verifier_state *
+sanitize_speculative_path(struct bpf_verifier_env *env,
+			  const struct bpf_insn *insn,
+			  u32 next_idx, u32 curr_idx)
+{
+	struct bpf_verifier_state *branch;
+	struct bpf_reg_state *regs;
+
+	branch = push_stack(env, next_idx, curr_idx, true);
+	if (branch && insn) {
+		regs = branch->frame[branch->curframe]->regs;
+		if (BPF_SRC(insn->code) == BPF_K) {
+			mark_reg_unknown(env, regs, insn->dst_reg);
+		} else if (BPF_SRC(insn->code) == BPF_X) {
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			mark_reg_unknown(env, regs, insn->src_reg);
+		}
+	}
+	return branch;
+}
+
+static int sanitize_ptr_alu(struct bpf_verifier_env *env,
+			    struct bpf_insn *insn,
+			    const struct bpf_reg_state *ptr_reg,
+			    const struct bpf_reg_state *off_reg,
+			    struct bpf_reg_state *dst_reg,
+			    struct bpf_sanitize_info *info,
+			    const bool commit_window)
+{
+	struct bpf_insn_aux_data *aux = commit_window ? cur_aux(env) : &info->aux;
+	struct bpf_verifier_state *vstate = env->cur_state;
+	bool off_is_imm = tnum_is_const(off_reg->var_off);
+	bool off_is_neg = off_reg->smin_value < 0;
+	bool ptr_is_dst_reg = ptr_reg == dst_reg;
+	u8 opcode = BPF_OP(insn->code);
+	u32 alu_state, alu_limit;
+	struct bpf_reg_state tmp;
+	bool ret;
+	int err;
+
+	if (can_skip_alu_sanitation(env, insn))
+		return 0;
+
+	/* We already marked aux for masking from non-speculative
+	 * paths, thus we got here in the first place. We only care
+	 * to explore bad access from here.
+	 */
+	if (vstate->speculative)
+		goto do_sim;
+
+	if (!commit_window) {
+		if (!tnum_is_const(off_reg->var_off) &&
+		    (off_reg->smin_value < 0) != (off_reg->smax_value < 0))
+			return REASON_BOUNDS;
+
+		info->mask_to_left = (opcode == BPF_ADD &&  off_is_neg) ||
+				     (opcode == BPF_SUB && !off_is_neg);
+	}
+
+	err = retrieve_ptr_limit(ptr_reg, &alu_limit, info->mask_to_left);
+	if (err < 0)
+		return err;
+
+	if (commit_window) {
+		/* In commit phase we narrow the masking window based on
+		 * the observed pointer move after the simulated operation.
+		 */
+		alu_state = info->aux.alu_state;
+		alu_limit = abs(info->aux.alu_limit - alu_limit);
+	} else {
+		alu_state  = off_is_neg ? BPF_ALU_NEG_VALUE : 0;
+		alu_state |= off_is_imm ? BPF_ALU_IMMEDIATE : 0;
+		alu_state |= ptr_is_dst_reg ?
+			     BPF_ALU_SANITIZE_SRC : BPF_ALU_SANITIZE_DST;
+
+		/* Limit pruning on unknown scalars to enable deep search for
+		 * potential masking differences from other program paths.
+		 */
+		if (!off_is_imm)
+			env->explore_alu_limits = true;
+	}
+
+	err = update_alu_sanitation_state(aux, alu_state, alu_limit);
+	if (err < 0)
+		return err;
+do_sim:
+	/* If we're in commit phase, we're done here given we already
+	 * pushed the truncated dst_reg into the speculative verification
+	 * stack.
+	 *
+	 * Also, when register is a known constant, we rewrite register-based
+	 * operation to immediate-based, and thus do not need masking (and as
+	 * a consequence, do not need to simulate the zero-truncation either).
+	 */
+	if (commit_window || off_is_imm)
+		return 0;
+
+	/* Simulate and find potential out-of-bounds access under
+	 * speculative execution from truncation as a result of
+	 * masking when off was not within expected range. If off
+	 * sits in dst, then we temporarily need to move ptr there
+	 * to simulate dst (== 0) +/-= ptr. Needed, for example,
+	 * for cases where we use K-based arithmetic in one direction
+	 * and truncated reg-based in the other in order to explore
+	 * bad access.
+	 */
+	if (!ptr_is_dst_reg) {
+		tmp = *dst_reg;
+		copy_register_state(dst_reg, ptr_reg);
+	}
+	ret = sanitize_speculative_path(env, NULL, env->insn_idx + 1,
+					env->insn_idx);
+	if (!ptr_is_dst_reg && ret)
+		*dst_reg = tmp;
+	return !ret ? REASON_STACK : 0;
+}
+
+static void sanitize_mark_insn_seen(struct bpf_verifier_env *env)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+
+	/* If we simulate paths under speculation, we don't update the
+	 * insn as 'seen' such that when we verify unreachable paths in
+	 * the non-speculative domain, sanitize_dead_code() can still
+	 * rewrite/sanitize them.
+	 */
+	if (!vstate->speculative)
+		env->insn_aux_data[env->insn_idx].seen = env->pass_cnt;
+}
+
+static int sanitize_err(struct bpf_verifier_env *env,
+			const struct bpf_insn *insn, int reason,
+			const struct bpf_reg_state *off_reg,
+			const struct bpf_reg_state *dst_reg)
+{
+	static const char *err = "pointer arithmetic with it prohibited for !root";
+	const char *op = BPF_OP(insn->code) == BPF_ADD ? "add" : "sub";
+	u32 dst = insn->dst_reg, src = insn->src_reg;
+
+	switch (reason) {
+	case REASON_BOUNDS:
+		verbose(env, "R%d has unknown scalar with mixed signed bounds, %s\n",
+			off_reg == dst_reg ? dst : src, err);
+		break;
+	case REASON_TYPE:
+		verbose(env, "R%d has pointer with unsupported alu operation, %s\n",
+			off_reg == dst_reg ? src : dst, err);
+		break;
+	case REASON_PATHS:
+		verbose(env, "R%d tried to %s from different maps, paths or scalars, %s\n",
+			dst, op, err);
+		break;
+	case REASON_LIMIT:
+		verbose(env, "R%d tried to %s beyond pointer bounds, %s\n",
+			dst, op, err);
+		break;
+	case REASON_STACK:
+		verbose(env, "R%d could not be pushed for speculative verification, %s\n",
+			dst, err);
+		break;
+	default:
+		verbose(env, "verifier internal error: unknown reason (%d)\n",
+			reason);
+		break;
+	}
+
+	return -EACCES;
+}
+
+/* check that stack access falls within stack limits and that 'reg' doesn't
+ * have a variable offset.
+ *
+ * Variable offset is prohibited for unprivileged mode for simplicity since it
+ * requires corresponding support in Spectre masking for stack ALU.  See also
+ * retrieve_ptr_limit().
+ *
+ *
+ * 'off' includes 'reg->off'.
+ */
+static int check_stack_access_for_ptr_arithmetic(
+				struct bpf_verifier_env *env,
+				int regno,
+				const struct bpf_reg_state *reg,
+				int off)
+{
+	if (!tnum_is_const(reg->var_off)) {
+		char tn_buf[48];
+
+		tnum_strn(tn_buf, sizeof(tn_buf), reg->var_off);
+		verbose(env, "R%d variable stack access prohibited for !root, var_off=%s off=%d\n",
+			regno, tn_buf, off);
+		return -EACCES;
+	}
+
+	if (off >= 0 || off < -MAX_BPF_STACK) {
+		verbose(env, "R%d stack pointer arithmetic goes out of range, "
+			"prohibited for !root; off=%d\n", regno, off);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int sanitize_check_bounds(struct bpf_verifier_env *env,
+				 const struct bpf_insn *insn,
+				 const struct bpf_reg_state *dst_reg)
+{
+	u32 dst = insn->dst_reg;
+
+	/* For unprivileged we require that resulting offset must be in bounds
+	 * in order to be able to sanitize access later on.
+	 */
+	if (env->bypass_spec_v1)
+		return 0;
+
+	switch (dst_reg->type) {
+	case PTR_TO_STACK:
+		if (check_stack_access_for_ptr_arithmetic(env, dst, dst_reg,
+					dst_reg->off + dst_reg->var_off.value))
+			return -EACCES;
+		break;
+	case PTR_TO_MAP_VALUE:
+		if (check_map_access(env, dst, dst_reg->off, 1, false, ACCESS_HELPER)) {
+			verbose(env, "R%d pointer arithmetic of map value goes out of range, "
+				"prohibited for !root\n", dst);
+			return -EACCES;
+		}
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* Handles arithmetic on a pointer and a scalar: computes new min/max and var_off.
+ * Caller should also handle BPF_MOV case separately.
+ * If we return -EACCES, caller may want to try again treating pointer as a
+ * scalar.  So we only emit a diagnostic if !env->allow_ptr_leaks.
+ */
+static int adjust_ptr_min_max_vals(struct bpf_verifier_env *env,
+				   struct bpf_insn *insn,
+				   const struct bpf_reg_state *ptr_reg,
+				   const struct bpf_reg_state *off_reg)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *regs = state->regs, *dst_reg;
+	bool known = tnum_is_const(off_reg->var_off);
+	s64 smin_val = off_reg->smin_value, smax_val = off_reg->smax_value,
+	    smin_ptr = ptr_reg->smin_value, smax_ptr = ptr_reg->smax_value;
+	u64 umin_val = off_reg->umin_value, umax_val = off_reg->umax_value,
+	    umin_ptr = ptr_reg->umin_value, umax_ptr = ptr_reg->umax_value;
+	struct bpf_sanitize_info info = {};
+	u8 opcode = BPF_OP(insn->code);
+	u32 dst = insn->dst_reg;
+	int ret;
+
+	dst_reg = &regs[dst];
+
+	if ((known && (smin_val != smax_val || umin_val != umax_val)) ||
+	    smin_val > smax_val || umin_val > umax_val) {
+		/* Taint dst register if offset had invalid bounds derived from
+		 * e.g. dead branches.
+		 */
+		__mark_reg_unknown(env, dst_reg);
+		return 0;
+	}
+
+	if (BPF_CLASS(insn->code) != BPF_ALU64) {
+		/* 32-bit ALU ops on pointers produce (meaningless) scalars */
+		if (opcode == BPF_SUB && env->allow_ptr_leaks) {
+			__mark_reg_unknown(env, dst_reg);
+			return 0;
+		}
+
+		verbose(env,
+			"R%d 32-bit pointer arithmetic prohibited\n",
+			dst);
+		return -EACCES;
+	}
+
+	if (ptr_reg->type & PTR_MAYBE_NULL) {
+		verbose(env, "R%d pointer arithmetic on %s prohibited, null-check it first\n",
+			dst, reg_type_str(env, ptr_reg->type));
+		return -EACCES;
+	}
+
+	switch (base_type(ptr_reg->type)) {
+	case PTR_TO_FLOW_KEYS:
+		if (known)
+			break;
+		fallthrough;
+	case CONST_PTR_TO_MAP:
+		/* smin_val represents the known value */
+		if (known && smin_val == 0 && opcode == BPF_ADD)
+			break;
+		fallthrough;
+	case PTR_TO_PACKET_END:
+	case PTR_TO_SOCKET:
+	case PTR_TO_SOCK_COMMON:
+	case PTR_TO_TCP_SOCK:
+	case PTR_TO_XDP_SOCK:
+		verbose(env, "R%d pointer arithmetic on %s prohibited\n",
+			dst, reg_type_str(env, ptr_reg->type));
+		return -EACCES;
+	default:
+		break;
+	}
+
+	/* In case of 'scalar += pointer', dst_reg inherits pointer type and id.
+	 * The id may be overwritten later if we create a new variable offset.
+	 */
+	dst_reg->type = ptr_reg->type;
+	dst_reg->id = ptr_reg->id;
+
+	if (!check_reg_sane_offset(env, off_reg, ptr_reg->type) ||
+	    !check_reg_sane_offset(env, ptr_reg, ptr_reg->type))
+		return -EINVAL;
+
+	/* pointer types do not carry 32-bit bounds at the moment. */
+	__mark_reg32_unbounded(dst_reg);
+
+	if (sanitize_needed(opcode)) {
+		ret = sanitize_ptr_alu(env, insn, ptr_reg, off_reg, dst_reg,
+				       &info, false);
+		if (ret < 0)
+			return sanitize_err(env, insn, ret, off_reg, dst_reg);
+	}
+
+	switch (opcode) {
+	case BPF_ADD:
+		/* We can take a fixed offset as long as it doesn't overflow
+		 * the s32 'off' field
+		 */
+		if (known && (ptr_reg->off + smin_val ==
+			      (s64)(s32)(ptr_reg->off + smin_val))) {
+			/* pointer += K.  Accumulate it into fixed offset */
+			dst_reg->smin_value = smin_ptr;
+			dst_reg->smax_value = smax_ptr;
+			dst_reg->umin_value = umin_ptr;
+			dst_reg->umax_value = umax_ptr;
+			dst_reg->var_off = ptr_reg->var_off;
+			dst_reg->off = ptr_reg->off + smin_val;
+			dst_reg->raw = ptr_reg->raw;
+			break;
+		}
+		/* A new variable offset is created.  Note that off_reg->off
+		 * == 0, since it's a scalar.
+		 * dst_reg gets the pointer type and since some positive
+		 * integer value was added to the pointer, give it a new 'id'
+		 * if it's a PTR_TO_PACKET.
+		 * this creates a new 'base' pointer, off_reg (variable) gets
+		 * added into the variable offset, and we copy the fixed offset
+		 * from ptr_reg.
+		 */
+		if (signed_add_overflows(smin_ptr, smin_val) ||
+		    signed_add_overflows(smax_ptr, smax_val)) {
+			dst_reg->smin_value = S64_MIN;
+			dst_reg->smax_value = S64_MAX;
+		} else {
+			dst_reg->smin_value = smin_ptr + smin_val;
+			dst_reg->smax_value = smax_ptr + smax_val;
+		}
+		if (umin_ptr + umin_val < umin_ptr ||
+		    umax_ptr + umax_val < umax_ptr) {
+			dst_reg->umin_value = 0;
+			dst_reg->umax_value = U64_MAX;
+		} else {
+			dst_reg->umin_value = umin_ptr + umin_val;
+			dst_reg->umax_value = umax_ptr + umax_val;
+		}
+		dst_reg->var_off = tnum_add(ptr_reg->var_off, off_reg->var_off);
+		dst_reg->off = ptr_reg->off;
+		dst_reg->raw = ptr_reg->raw;
+		if (reg_is_pkt_pointer(ptr_reg)) {
+			dst_reg->id = ++env->id_gen;
+			/* something was added to pkt_ptr, set range to zero */
+			memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
+		}
+		break;
+	case BPF_SUB:
+		if (dst_reg == off_reg) {
+			/* scalar -= pointer.  Creates an unknown scalar */
+			verbose(env, "R%d tried to subtract pointer from scalar\n",
+				dst);
+			return -EACCES;
+		}
+		/* We don't allow subtraction from FP, because (according to
+		 * test_verifier.c test "invalid fp arithmetic", JITs might not
+		 * be able to deal with it.
+		 */
+		if (ptr_reg->type == PTR_TO_STACK) {
+			verbose(env, "R%d subtraction from stack pointer prohibited\n",
+				dst);
+			return -EACCES;
+		}
+		if (known && (ptr_reg->off - smin_val ==
+			      (s64)(s32)(ptr_reg->off - smin_val))) {
+			/* pointer -= K.  Subtract it from fixed offset */
+			dst_reg->smin_value = smin_ptr;
+			dst_reg->smax_value = smax_ptr;
+			dst_reg->umin_value = umin_ptr;
+			dst_reg->umax_value = umax_ptr;
+			dst_reg->var_off = ptr_reg->var_off;
+			dst_reg->id = ptr_reg->id;
+			dst_reg->off = ptr_reg->off - smin_val;
+			dst_reg->raw = ptr_reg->raw;
+			break;
+		}
+		/* A new variable offset is created.  If the subtrahend is known
+		 * nonnegative, then any reg->range we had before is still good.
+		 */
+		if (signed_sub_overflows(smin_ptr, smax_val) ||
+		    signed_sub_overflows(smax_ptr, smin_val)) {
+			/* Overflow possible, we know nothing */
+			dst_reg->smin_value = S64_MIN;
+			dst_reg->smax_value = S64_MAX;
+		} else {
+			dst_reg->smin_value = smin_ptr - smax_val;
+			dst_reg->smax_value = smax_ptr - smin_val;
+		}
+		if (umin_ptr < umax_val) {
+			/* Overflow possible, we know nothing */
+			dst_reg->umin_value = 0;
+			dst_reg->umax_value = U64_MAX;
+		} else {
+			/* Cannot overflow (as long as bounds are consistent) */
+			dst_reg->umin_value = umin_ptr - umax_val;
+			dst_reg->umax_value = umax_ptr - umin_val;
+		}
+		dst_reg->var_off = tnum_sub(ptr_reg->var_off, off_reg->var_off);
+		dst_reg->off = ptr_reg->off;
+		dst_reg->raw = ptr_reg->raw;
+		if (reg_is_pkt_pointer(ptr_reg)) {
+			dst_reg->id = ++env->id_gen;
+			/* something was added to pkt_ptr, set range to zero */
+			if (smin_val < 0)
+				memset(&dst_reg->raw, 0, sizeof(dst_reg->raw));
+		}
+		break;
+	case BPF_AND:
+	case BPF_OR:
+	case BPF_XOR:
+		/* bitwise ops on pointers are troublesome, prohibit. */
+		verbose(env, "R%d bitwise operator %s on pointer prohibited\n",
+			dst, bpf_alu_string[opcode >> 4]);
+		return -EACCES;
+	default:
+		/* other operators (e.g. MUL,LSH) produce non-pointer results */
+		verbose(env, "R%d pointer arithmetic with %s operator prohibited\n",
+			dst, bpf_alu_string[opcode >> 4]);
+		return -EACCES;
+	}
+
+	if (!check_reg_sane_offset(env, dst_reg, ptr_reg->type))
+		return -EINVAL;
+	reg_bounds_sync(dst_reg);
+	if (sanitize_check_bounds(env, insn, dst_reg) < 0)
+		return -EACCES;
+	if (sanitize_needed(opcode)) {
+		ret = sanitize_ptr_alu(env, insn, dst_reg, off_reg, dst_reg,
+				       &info, true);
+		if (ret < 0)
+			return sanitize_err(env, insn, ret, off_reg, dst_reg);
+	}
+
+	return 0;
+}
+
+static void scalar32_min_max_add(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	s32 smin_val = src_reg->s32_min_value;
+	s32 smax_val = src_reg->s32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (signed_add32_overflows(dst_reg->s32_min_value, smin_val) ||
+	    signed_add32_overflows(dst_reg->s32_max_value, smax_val)) {
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		dst_reg->s32_min_value += smin_val;
+		dst_reg->s32_max_value += smax_val;
+	}
+	if (dst_reg->u32_min_value + umin_val < umin_val ||
+	    dst_reg->u32_max_value + umax_val < umax_val) {
+		dst_reg->u32_min_value = 0;
+		dst_reg->u32_max_value = U32_MAX;
+	} else {
+		dst_reg->u32_min_value += umin_val;
+		dst_reg->u32_max_value += umax_val;
+	}
+}
+
+static void scalar_min_max_add(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	s64 smin_val = src_reg->smin_value;
+	s64 smax_val = src_reg->smax_value;
+	u64 umin_val = src_reg->umin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (signed_add_overflows(dst_reg->smin_value, smin_val) ||
+	    signed_add_overflows(dst_reg->smax_value, smax_val)) {
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		dst_reg->smin_value += smin_val;
+		dst_reg->smax_value += smax_val;
+	}
+	if (dst_reg->umin_value + umin_val < umin_val ||
+	    dst_reg->umax_value + umax_val < umax_val) {
+		dst_reg->umin_value = 0;
+		dst_reg->umax_value = U64_MAX;
+	} else {
+		dst_reg->umin_value += umin_val;
+		dst_reg->umax_value += umax_val;
+	}
+}
+
+static void scalar32_min_max_sub(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	s32 smin_val = src_reg->s32_min_value;
+	s32 smax_val = src_reg->s32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (signed_sub32_overflows(dst_reg->s32_min_value, smax_val) ||
+	    signed_sub32_overflows(dst_reg->s32_max_value, smin_val)) {
+		/* Overflow possible, we know nothing */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		dst_reg->s32_min_value -= smax_val;
+		dst_reg->s32_max_value -= smin_val;
+	}
+	if (dst_reg->u32_min_value < umax_val) {
+		/* Overflow possible, we know nothing */
+		dst_reg->u32_min_value = 0;
+		dst_reg->u32_max_value = U32_MAX;
+	} else {
+		/* Cannot overflow (as long as bounds are consistent) */
+		dst_reg->u32_min_value -= umax_val;
+		dst_reg->u32_max_value -= umin_val;
+	}
+}
+
+static void scalar_min_max_sub(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	s64 smin_val = src_reg->smin_value;
+	s64 smax_val = src_reg->smax_value;
+	u64 umin_val = src_reg->umin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (signed_sub_overflows(dst_reg->smin_value, smax_val) ||
+	    signed_sub_overflows(dst_reg->smax_value, smin_val)) {
+		/* Overflow possible, we know nothing */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		dst_reg->smin_value -= smax_val;
+		dst_reg->smax_value -= smin_val;
+	}
+	if (dst_reg->umin_value < umax_val) {
+		/* Overflow possible, we know nothing */
+		dst_reg->umin_value = 0;
+		dst_reg->umax_value = U64_MAX;
+	} else {
+		/* Cannot overflow (as long as bounds are consistent) */
+		dst_reg->umin_value -= umax_val;
+		dst_reg->umax_value -= umin_val;
+	}
+}
+
+static void scalar32_min_max_mul(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	s32 smin_val = src_reg->s32_min_value;
+	u32 umin_val = src_reg->u32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (smin_val < 0 || dst_reg->s32_min_value < 0) {
+		/* Ain't nobody got time to multiply that sign */
+		__mark_reg32_unbounded(dst_reg);
+		return;
+	}
+	/* Both values are positive, so we can work with unsigned and
+	 * copy the result to signed (unless it exceeds S32_MAX).
+	 */
+	if (umax_val > U16_MAX || dst_reg->u32_max_value > U16_MAX) {
+		/* Potential overflow, we know nothing */
+		__mark_reg32_unbounded(dst_reg);
+		return;
+	}
+	dst_reg->u32_min_value *= umin_val;
+	dst_reg->u32_max_value *= umax_val;
+	if (dst_reg->u32_max_value > S32_MAX) {
+		/* Overflow possible, we know nothing */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	}
+}
+
+static void scalar_min_max_mul(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	s64 smin_val = src_reg->smin_value;
+	u64 umin_val = src_reg->umin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (smin_val < 0 || dst_reg->smin_value < 0) {
+		/* Ain't nobody got time to multiply that sign */
+		__mark_reg64_unbounded(dst_reg);
+		return;
+	}
+	/* Both values are positive, so we can work with unsigned and
+	 * copy the result to signed (unless it exceeds S64_MAX).
+	 */
+	if (umax_val > U32_MAX || dst_reg->umax_value > U32_MAX) {
+		/* Potential overflow, we know nothing */
+		__mark_reg64_unbounded(dst_reg);
+		return;
+	}
+	dst_reg->umin_value *= umin_val;
+	dst_reg->umax_value *= umax_val;
+	if (dst_reg->umax_value > S64_MAX) {
+		/* Overflow possible, we know nothing */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	}
+}
+
+static void scalar32_min_max_and(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_subreg_is_const(src_reg->var_off);
+	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+	s32 smin_val = src_reg->s32_min_value;
+	u32 umax_val = src_reg->u32_max_value;
+
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
+		return;
+	}
+
+	/* We get our minimum from the var_off, since that's inherently
+	 * bitwise.  Our maximum is the minimum of the operands' maxima.
+	 */
+	dst_reg->u32_min_value = var32_off.value;
+	dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val);
+	if (dst_reg->s32_min_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ANDing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		/* ANDing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	}
+}
+
+static void scalar_min_max_and(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_is_const(src_reg->var_off);
+	bool dst_known = tnum_is_const(dst_reg->var_off);
+	s64 smin_val = src_reg->smin_value;
+	u64 umax_val = src_reg->umax_value;
+
+	if (src_known && dst_known) {
+		__mark_reg_known(dst_reg, dst_reg->var_off.value);
+		return;
+	}
+
+	/* We get our minimum from the var_off, since that's inherently
+	 * bitwise.  Our maximum is the minimum of the operands' maxima.
+	 */
+	dst_reg->umin_value = dst_reg->var_off.value;
+	dst_reg->umax_value = min(dst_reg->umax_value, umax_val);
+	if (dst_reg->smin_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ANDing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		/* ANDing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	}
+	/* We may learn something more from the var_off */
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_or(struct bpf_reg_state *dst_reg,
+				struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_subreg_is_const(src_reg->var_off);
+	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+	s32 smin_val = src_reg->s32_min_value;
+	u32 umin_val = src_reg->u32_min_value;
+
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
+		return;
+	}
+
+	/* We get our maximum from the var_off, and our minimum is the
+	 * maximum of the operands' minima
+	 */
+	dst_reg->u32_min_value = max(dst_reg->u32_min_value, umin_val);
+	dst_reg->u32_max_value = var32_off.value | var32_off.mask;
+	if (dst_reg->s32_min_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ORing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	} else {
+		/* ORing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	}
+}
+
+static void scalar_min_max_or(struct bpf_reg_state *dst_reg,
+			      struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_is_const(src_reg->var_off);
+	bool dst_known = tnum_is_const(dst_reg->var_off);
+	s64 smin_val = src_reg->smin_value;
+	u64 umin_val = src_reg->umin_value;
+
+	if (src_known && dst_known) {
+		__mark_reg_known(dst_reg, dst_reg->var_off.value);
+		return;
+	}
+
+	/* We get our maximum from the var_off, and our minimum is the
+	 * maximum of the operands' minima
+	 */
+	dst_reg->umin_value = max(dst_reg->umin_value, umin_val);
+	dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
+	if (dst_reg->smin_value < 0 || smin_val < 0) {
+		/* Lose signed bounds when ORing negative numbers,
+		 * ain't nobody got time for that.
+		 */
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	} else {
+		/* ORing two positives gives a positive, so safe to
+		 * cast result into s64.
+		 */
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	}
+	/* We may learn something more from the var_off */
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_xor(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_subreg_is_const(src_reg->var_off);
+	bool dst_known = tnum_subreg_is_const(dst_reg->var_off);
+	struct tnum var32_off = tnum_subreg(dst_reg->var_off);
+	s32 smin_val = src_reg->s32_min_value;
+
+	if (src_known && dst_known) {
+		__mark_reg32_known(dst_reg, var32_off.value);
+		return;
+	}
+
+	/* We get both minimum and maximum from the var32_off. */
+	dst_reg->u32_min_value = var32_off.value;
+	dst_reg->u32_max_value = var32_off.value | var32_off.mask;
+
+	if (dst_reg->s32_min_value >= 0 && smin_val >= 0) {
+		/* XORing two positive sign numbers gives a positive,
+		 * so safe to cast u32 result into s32.
+		 */
+		dst_reg->s32_min_value = dst_reg->u32_min_value;
+		dst_reg->s32_max_value = dst_reg->u32_max_value;
+	} else {
+		dst_reg->s32_min_value = S32_MIN;
+		dst_reg->s32_max_value = S32_MAX;
+	}
+}
+
+static void scalar_min_max_xor(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	bool src_known = tnum_is_const(src_reg->var_off);
+	bool dst_known = tnum_is_const(dst_reg->var_off);
+	s64 smin_val = src_reg->smin_value;
+
+	if (src_known && dst_known) {
+		/* dst_reg->var_off.value has been updated earlier */
+		__mark_reg_known(dst_reg, dst_reg->var_off.value);
+		return;
+	}
+
+	/* We get both minimum and maximum from the var_off. */
+	dst_reg->umin_value = dst_reg->var_off.value;
+	dst_reg->umax_value = dst_reg->var_off.value | dst_reg->var_off.mask;
+
+	if (dst_reg->smin_value >= 0 && smin_val >= 0) {
+		/* XORing two positive sign numbers gives a positive,
+		 * so safe to cast u64 result into s64.
+		 */
+		dst_reg->smin_value = dst_reg->umin_value;
+		dst_reg->smax_value = dst_reg->umax_value;
+	} else {
+		dst_reg->smin_value = S64_MIN;
+		dst_reg->smax_value = S64_MAX;
+	}
+
+	__update_reg_bounds(dst_reg);
+}
+
+static void __scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
+				   u64 umin_val, u64 umax_val)
+{
+	/* We lose all sign bit information (except what we can pick
+	 * up from var_off)
+	 */
+	dst_reg->s32_min_value = S32_MIN;
+	dst_reg->s32_max_value = S32_MAX;
+	/* If we might shift our top bit out, then we know nothing */
+	if (umax_val > 31 || dst_reg->u32_max_value > 1ULL << (31 - umax_val)) {
+		dst_reg->u32_min_value = 0;
+		dst_reg->u32_max_value = U32_MAX;
+	} else {
+		dst_reg->u32_min_value <<= umin_val;
+		dst_reg->u32_max_value <<= umax_val;
+	}
+}
+
+static void scalar32_min_max_lsh(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	u32 umax_val = src_reg->u32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+	/* u32 alu operation will zext upper bits */
+	struct tnum subreg = tnum_subreg(dst_reg->var_off);
+
+	__scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
+	dst_reg->var_off = tnum_subreg(tnum_lshift(subreg, umin_val));
+	/* Not required but being careful mark reg64 bounds as unknown so
+	 * that we are forced to pick them up from tnum and zext later and
+	 * if some path skips this step we are still safe.
+	 */
+	__mark_reg64_unbounded(dst_reg);
+	__update_reg32_bounds(dst_reg);
+}
+
+static void __scalar64_min_max_lsh(struct bpf_reg_state *dst_reg,
+				   u64 umin_val, u64 umax_val)
+{
+	/* Special case <<32 because it is a common compiler pattern to sign
+	 * extend subreg by doing <<32 s>>32. In this case if 32bit bounds are
+	 * positive we know this shift will also be positive so we can track
+	 * bounds correctly. Otherwise we lose all sign bit information except
+	 * what we can pick up from var_off. Perhaps we can generalize this
+	 * later to shifts of any length.
+	 */
+	if (umin_val == 32 && umax_val == 32 && dst_reg->s32_max_value >= 0)
+		dst_reg->smax_value = (s64)dst_reg->s32_max_value << 32;
+	else
+		dst_reg->smax_value = S64_MAX;
+
+	if (umin_val == 32 && umax_val == 32 && dst_reg->s32_min_value >= 0)
+		dst_reg->smin_value = (s64)dst_reg->s32_min_value << 32;
+	else
+		dst_reg->smin_value = S64_MIN;
+
+	/* If we might shift our top bit out, then we know nothing */
+	if (dst_reg->umax_value > 1ULL << (63 - umax_val)) {
+		dst_reg->umin_value = 0;
+		dst_reg->umax_value = U64_MAX;
+	} else {
+		dst_reg->umin_value <<= umin_val;
+		dst_reg->umax_value <<= umax_val;
+	}
+}
+
+static void scalar_min_max_lsh(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	u64 umax_val = src_reg->umax_value;
+	u64 umin_val = src_reg->umin_value;
+
+	/* scalar64 calc uses 32bit unshifted bounds so must be called first */
+	__scalar64_min_max_lsh(dst_reg, umin_val, umax_val);
+	__scalar32_min_max_lsh(dst_reg, umin_val, umax_val);
+
+	dst_reg->var_off = tnum_lshift(dst_reg->var_off, umin_val);
+	/* We may learn something more from the var_off */
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_rsh(struct bpf_reg_state *dst_reg,
+				 struct bpf_reg_state *src_reg)
+{
+	struct tnum subreg = tnum_subreg(dst_reg->var_off);
+	u32 umax_val = src_reg->u32_max_value;
+	u32 umin_val = src_reg->u32_min_value;
+
+	/* BPF_RSH is an unsigned shift.  If the value in dst_reg might
+	 * be negative, then either:
+	 * 1) src_reg might be zero, so the sign bit of the result is
+	 *    unknown, so we lose our signed bounds
+	 * 2) it's known negative, thus the unsigned bounds capture the
+	 *    signed bounds
+	 * 3) the signed bounds cross zero, so they tell us nothing
+	 *    about the result
+	 * If the value in dst_reg is known nonnegative, then again the
+	 * unsigned bounds capture the signed bounds.
+	 * Thus, in all cases it suffices to blow away our signed bounds
+	 * and rely on inferring new ones from the unsigned bounds and
+	 * var_off of the result.
+	 */
+	dst_reg->s32_min_value = S32_MIN;
+	dst_reg->s32_max_value = S32_MAX;
+
+	dst_reg->var_off = tnum_rshift(subreg, umin_val);
+	dst_reg->u32_min_value >>= umax_val;
+	dst_reg->u32_max_value >>= umin_val;
+
+	__mark_reg64_unbounded(dst_reg);
+	__update_reg32_bounds(dst_reg);
+}
+
+static void scalar_min_max_rsh(struct bpf_reg_state *dst_reg,
+			       struct bpf_reg_state *src_reg)
+{
+	u64 umax_val = src_reg->umax_value;
+	u64 umin_val = src_reg->umin_value;
+
+	/* BPF_RSH is an unsigned shift.  If the value in dst_reg might
+	 * be negative, then either:
+	 * 1) src_reg might be zero, so the sign bit of the result is
+	 *    unknown, so we lose our signed bounds
+	 * 2) it's known negative, thus the unsigned bounds capture the
+	 *    signed bounds
+	 * 3) the signed bounds cross zero, so they tell us nothing
+	 *    about the result
+	 * If the value in dst_reg is known nonnegative, then again the
+	 * unsigned bounds capture the signed bounds.
+	 * Thus, in all cases it suffices to blow away our signed bounds
+	 * and rely on inferring new ones from the unsigned bounds and
+	 * var_off of the result.
+	 */
+	dst_reg->smin_value = S64_MIN;
+	dst_reg->smax_value = S64_MAX;
+	dst_reg->var_off = tnum_rshift(dst_reg->var_off, umin_val);
+	dst_reg->umin_value >>= umax_val;
+	dst_reg->umax_value >>= umin_val;
+
+	/* Its not easy to operate on alu32 bounds here because it depends
+	 * on bits being shifted in. Take easy way out and mark unbounded
+	 * so we can recalculate later from tnum.
+	 */
+	__mark_reg32_unbounded(dst_reg);
+	__update_reg_bounds(dst_reg);
+}
+
+static void scalar32_min_max_arsh(struct bpf_reg_state *dst_reg,
+				  struct bpf_reg_state *src_reg)
+{
+	u64 umin_val = src_reg->u32_min_value;
+
+	/* Upon reaching here, src_known is true and
+	 * umax_val is equal to umin_val.
+	 */
+	dst_reg->s32_min_value = (u32)(((s32)dst_reg->s32_min_value) >> umin_val);
+	dst_reg->s32_max_value = (u32)(((s32)dst_reg->s32_max_value) >> umin_val);
+
+	dst_reg->var_off = tnum_arshift(tnum_subreg(dst_reg->var_off), umin_val, 32);
+
+	/* blow away the dst_reg umin_value/umax_value and rely on
+	 * dst_reg var_off to refine the result.
+	 */
+	dst_reg->u32_min_value = 0;
+	dst_reg->u32_max_value = U32_MAX;
+
+	__mark_reg64_unbounded(dst_reg);
+	__update_reg32_bounds(dst_reg);
+}
+
+static void scalar_min_max_arsh(struct bpf_reg_state *dst_reg,
+				struct bpf_reg_state *src_reg)
+{
+	u64 umin_val = src_reg->umin_value;
+
+	/* Upon reaching here, src_known is true and umax_val is equal
+	 * to umin_val.
+	 */
+	dst_reg->smin_value >>= umin_val;
+	dst_reg->smax_value >>= umin_val;
+
+	dst_reg->var_off = tnum_arshift(dst_reg->var_off, umin_val, 64);
+
+	/* blow away the dst_reg umin_value/umax_value and rely on
+	 * dst_reg var_off to refine the result.
+	 */
+	dst_reg->umin_value = 0;
+	dst_reg->umax_value = U64_MAX;
+
+	/* Its not easy to operate on alu32 bounds here because it depends
+	 * on bits being shifted in from upper 32-bits. Take easy way out
+	 * and mark unbounded so we can recalculate later from tnum.
+	 */
+	__mark_reg32_unbounded(dst_reg);
+	__update_reg_bounds(dst_reg);
+}
+
+/* WARNING: This function does calculations on 64-bit values, but the actual
+ * execution may occur on 32-bit values. Therefore, things like bitshifts
+ * need extra checks in the 32-bit case.
+ */
+static int adjust_scalar_min_max_vals(struct bpf_verifier_env *env,
+				      struct bpf_insn *insn,
+				      struct bpf_reg_state *dst_reg,
+				      struct bpf_reg_state src_reg)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	u8 opcode = BPF_OP(insn->code);
+	bool src_known;
+	s64 smin_val, smax_val;
+	u64 umin_val, umax_val;
+	s32 s32_min_val, s32_max_val;
+	u32 u32_min_val, u32_max_val;
+	u64 insn_bitness = (BPF_CLASS(insn->code) == BPF_ALU64) ? 64 : 32;
+	bool alu32 = (BPF_CLASS(insn->code) != BPF_ALU64);
+	int ret;
+
+	smin_val = src_reg.smin_value;
+	smax_val = src_reg.smax_value;
+	umin_val = src_reg.umin_value;
+	umax_val = src_reg.umax_value;
+
+	s32_min_val = src_reg.s32_min_value;
+	s32_max_val = src_reg.s32_max_value;
+	u32_min_val = src_reg.u32_min_value;
+	u32_max_val = src_reg.u32_max_value;
+
+	if (alu32) {
+		src_known = tnum_subreg_is_const(src_reg.var_off);
+		if ((src_known &&
+		     (s32_min_val != s32_max_val || u32_min_val != u32_max_val)) ||
+		    s32_min_val > s32_max_val || u32_min_val > u32_max_val) {
+			/* Taint dst register if offset had invalid bounds
+			 * derived from e.g. dead branches.
+			 */
+			__mark_reg_unknown(env, dst_reg);
+			return 0;
+		}
+	} else {
+		src_known = tnum_is_const(src_reg.var_off);
+		if ((src_known &&
+		     (smin_val != smax_val || umin_val != umax_val)) ||
+		    smin_val > smax_val || umin_val > umax_val) {
+			/* Taint dst register if offset had invalid bounds
+			 * derived from e.g. dead branches.
+			 */
+			__mark_reg_unknown(env, dst_reg);
+			return 0;
+		}
+	}
+
+	if (!src_known &&
+	    opcode != BPF_ADD && opcode != BPF_SUB && opcode != BPF_AND) {
+		__mark_reg_unknown(env, dst_reg);
+		return 0;
+	}
+
+	if (sanitize_needed(opcode)) {
+		ret = sanitize_val_alu(env, insn);
+		if (ret < 0)
+			return sanitize_err(env, insn, ret, NULL, NULL);
+	}
+
+	/* Calculate sign/unsigned bounds and tnum for alu32 and alu64 bit ops.
+	 * There are two classes of instructions: The first class we track both
+	 * alu32 and alu64 sign/unsigned bounds independently this provides the
+	 * greatest amount of precision when alu operations are mixed with jmp32
+	 * operations. These operations are BPF_ADD, BPF_SUB, BPF_MUL, BPF_ADD,
+	 * and BPF_OR. This is possible because these ops have fairly easy to
+	 * understand and calculate behavior in both 32-bit and 64-bit alu ops.
+	 * See alu32 verifier tests for examples. The second class of
+	 * operations, BPF_LSH, BPF_RSH, and BPF_ARSH, however are not so easy
+	 * with regards to tracking sign/unsigned bounds because the bits may
+	 * cross subreg boundaries in the alu64 case. When this happens we mark
+	 * the reg unbounded in the subreg bound space and use the resulting
+	 * tnum to calculate an approximation of the sign/unsigned bounds.
+	 */
+	switch (opcode) {
+	case BPF_ADD:
+		scalar32_min_max_add(dst_reg, &src_reg);
+		scalar_min_max_add(dst_reg, &src_reg);
+		dst_reg->var_off = tnum_add(dst_reg->var_off, src_reg.var_off);
+		break;
+	case BPF_SUB:
+		scalar32_min_max_sub(dst_reg, &src_reg);
+		scalar_min_max_sub(dst_reg, &src_reg);
+		dst_reg->var_off = tnum_sub(dst_reg->var_off, src_reg.var_off);
+		break;
+	case BPF_MUL:
+		dst_reg->var_off = tnum_mul(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_mul(dst_reg, &src_reg);
+		scalar_min_max_mul(dst_reg, &src_reg);
+		break;
+	case BPF_AND:
+		dst_reg->var_off = tnum_and(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_and(dst_reg, &src_reg);
+		scalar_min_max_and(dst_reg, &src_reg);
+		break;
+	case BPF_OR:
+		dst_reg->var_off = tnum_or(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_or(dst_reg, &src_reg);
+		scalar_min_max_or(dst_reg, &src_reg);
+		break;
+	case BPF_XOR:
+		dst_reg->var_off = tnum_xor(dst_reg->var_off, src_reg.var_off);
+		scalar32_min_max_xor(dst_reg, &src_reg);
+		scalar_min_max_xor(dst_reg, &src_reg);
+		break;
+	case BPF_LSH:
+		if (umax_val >= insn_bitness) {
+			/* Shifts greater than 31 or 63 are undefined.
+			 * This includes shifts by a negative number.
+			 */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			break;
+		}
+		if (alu32)
+			scalar32_min_max_lsh(dst_reg, &src_reg);
+		else
+			scalar_min_max_lsh(dst_reg, &src_reg);
+		break;
+	case BPF_RSH:
+		if (umax_val >= insn_bitness) {
+			/* Shifts greater than 31 or 63 are undefined.
+			 * This includes shifts by a negative number.
+			 */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			break;
+		}
+		if (alu32)
+			scalar32_min_max_rsh(dst_reg, &src_reg);
+		else
+			scalar_min_max_rsh(dst_reg, &src_reg);
+		break;
+	case BPF_ARSH:
+		if (umax_val >= insn_bitness) {
+			/* Shifts greater than 31 or 63 are undefined.
+			 * This includes shifts by a negative number.
+			 */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			break;
+		}
+		if (alu32)
+			scalar32_min_max_arsh(dst_reg, &src_reg);
+		else
+			scalar_min_max_arsh(dst_reg, &src_reg);
+		break;
+	default:
+		mark_reg_unknown(env, regs, insn->dst_reg);
+		break;
+	}
+
+	/* ALU32 ops are zero extended into 64bit register */
+	if (alu32)
+		zext_32_to_64(dst_reg);
+	reg_bounds_sync(dst_reg);
+	return 0;
+}
+
+/* Handles ALU ops other than BPF_END, BPF_NEG and BPF_MOV: computes new min/max
+ * and var_off.
+ */
+static int adjust_reg_min_max_vals(struct bpf_verifier_env *env,
+				   struct bpf_insn *insn)
+{
+	struct bpf_verifier_state *vstate = env->cur_state;
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *regs = state->regs, *dst_reg, *src_reg;
+	struct bpf_reg_state *ptr_reg = NULL, off_reg = {0};
+	u8 opcode = BPF_OP(insn->code);
+	int err;
+
+	dst_reg = &regs[insn->dst_reg];
+	src_reg = NULL;
+	if (dst_reg->type != SCALAR_VALUE)
+		ptr_reg = dst_reg;
+	else
+		/* Make sure ID is cleared otherwise dst_reg min/max could be
+		 * incorrectly propagated into other registers by find_equal_scalars()
+		 */
+		dst_reg->id = 0;
+	if (BPF_SRC(insn->code) == BPF_X) {
+		src_reg = &regs[insn->src_reg];
+		if (src_reg->type != SCALAR_VALUE) {
+			if (dst_reg->type != SCALAR_VALUE) {
+				/* Combining two pointers by any ALU op yields
+				 * an arbitrary scalar. Disallow all math except
+				 * pointer subtraction
+				 */
+				if (opcode == BPF_SUB && env->allow_ptr_leaks) {
+					mark_reg_unknown(env, regs, insn->dst_reg);
+					return 0;
+				}
+				verbose(env, "R%d pointer %s pointer prohibited\n",
+					insn->dst_reg,
+					bpf_alu_string[opcode >> 4]);
+				return -EACCES;
+			} else {
+				/* scalar += pointer
+				 * This is legal, but we have to reverse our
+				 * src/dest handling in computing the range
+				 */
+				err = mark_chain_precision(env, insn->dst_reg);
+				if (err)
+					return err;
+				return adjust_ptr_min_max_vals(env, insn,
+							       src_reg, dst_reg);
+			}
+		} else if (ptr_reg) {
+			/* pointer += scalar */
+			err = mark_chain_precision(env, insn->src_reg);
+			if (err)
+				return err;
+			return adjust_ptr_min_max_vals(env, insn,
+						       dst_reg, src_reg);
+		} else if (dst_reg->precise) {
+			/* if dst_reg is precise, src_reg should be precise as well */
+			err = mark_chain_precision(env, insn->src_reg);
+			if (err)
+				return err;
+		}
+	} else {
+		/* Pretend the src is a reg with a known value, since we only
+		 * need to be able to read from this state.
+		 */
+		off_reg.type = SCALAR_VALUE;
+		__mark_reg_known(&off_reg, insn->imm);
+		src_reg = &off_reg;
+		if (ptr_reg) /* pointer += K */
+			return adjust_ptr_min_max_vals(env, insn,
+						       ptr_reg, src_reg);
+	}
+
+	/* Got here implies adding two SCALAR_VALUEs */
+	if (WARN_ON_ONCE(ptr_reg)) {
+		print_verifier_state(env, state, true);
+		verbose(env, "verifier internal error: unexpected ptr_reg\n");
+		return -EINVAL;
+	}
+	if (WARN_ON(!src_reg)) {
+		print_verifier_state(env, state, true);
+		verbose(env, "verifier internal error: no src_reg\n");
+		return -EINVAL;
+	}
+	return adjust_scalar_min_max_vals(env, insn, dst_reg, *src_reg);
+}
+
+/* check validity of 32-bit and 64-bit arithmetic operations */
+static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	u8 opcode = BPF_OP(insn->code);
+	int err;
+
+	if (opcode == BPF_END || opcode == BPF_NEG) {
+		if (opcode == BPF_NEG) {
+			if (BPF_SRC(insn->code) != BPF_K ||
+			    insn->src_reg != BPF_REG_0 ||
+			    insn->off != 0 || insn->imm != 0) {
+				verbose(env, "BPF_NEG uses reserved fields\n");
+				return -EINVAL;
+			}
+		} else {
+			if (insn->src_reg != BPF_REG_0 || insn->off != 0 ||
+			    (insn->imm != 16 && insn->imm != 32 && insn->imm != 64) ||
+			    (BPF_CLASS(insn->code) == BPF_ALU64 &&
+			     BPF_SRC(insn->code) != BPF_TO_LE)) {
+				verbose(env, "BPF_END uses reserved fields\n");
+				return -EINVAL;
+			}
+		}
+
+		/* check src operand */
+		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+		if (err)
+			return err;
+
+		if (is_pointer_value(env, insn->dst_reg)) {
+			verbose(env, "R%d pointer arithmetic prohibited\n",
+				insn->dst_reg);
+			return -EACCES;
+		}
+
+		/* check dest operand */
+		err = check_reg_arg(env, insn->dst_reg, DST_OP);
+		if (err)
+			return err;
+
+	} else if (opcode == BPF_MOV) {
+
+		if (BPF_SRC(insn->code) == BPF_X) {
+			if (insn->imm != 0) {
+				verbose(env, "BPF_MOV uses reserved fields\n");
+				return -EINVAL;
+			}
+
+			if (BPF_CLASS(insn->code) == BPF_ALU) {
+				if (insn->off != 0 && insn->off != 8 && insn->off != 16) {
+					verbose(env, "BPF_MOV uses reserved fields\n");
+					return -EINVAL;
+				}
+			} else {
+				if (insn->off != 0 && insn->off != 8 && insn->off != 16 &&
+				    insn->off != 32) {
+					verbose(env, "BPF_MOV uses reserved fields\n");
+					return -EINVAL;
+				}
+			}
+
+			/* check src operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+		} else {
+			if (insn->src_reg != BPF_REG_0 || insn->off != 0) {
+				verbose(env, "BPF_MOV uses reserved fields\n");
+				return -EINVAL;
+			}
+		}
+
+		/* check dest operand, mark as required later */
+		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+		if (err)
+			return err;
+
+		if (BPF_SRC(insn->code) == BPF_X) {
+			struct bpf_reg_state *src_reg = regs + insn->src_reg;
+			struct bpf_reg_state *dst_reg = regs + insn->dst_reg;
+			bool need_id = src_reg->type == SCALAR_VALUE && !src_reg->id &&
+				       !tnum_is_const(src_reg->var_off);
+
+			if (BPF_CLASS(insn->code) == BPF_ALU64) {
+				if (insn->off == 0) {
+					/* case: R1 = R2
+					 * copy register state to dest reg
+					 */
+					if (need_id)
+						/* Assign src and dst registers the same ID
+						 * that will be used by find_equal_scalars()
+						 * to propagate min/max range.
+						 */
+						src_reg->id = ++env->id_gen;
+					copy_register_state(dst_reg, src_reg);
+					dst_reg->live |= REG_LIVE_WRITTEN;
+					dst_reg->subreg_def = DEF_NOT_SUBREG;
+				} else {
+					/* case: R1 = (s8, s16 s32)R2 */
+					if (is_pointer_value(env, insn->src_reg)) {
+						verbose(env,
+							"R%d sign-extension part of pointer\n",
+							insn->src_reg);
+						return -EACCES;
+					} else if (src_reg->type == SCALAR_VALUE) {
+						bool no_sext;
+
+						no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
+						if (no_sext && need_id)
+							src_reg->id = ++env->id_gen;
+						copy_register_state(dst_reg, src_reg);
+						if (!no_sext)
+							dst_reg->id = 0;
+						coerce_reg_to_size_sx(dst_reg, insn->off >> 3);
+						dst_reg->live |= REG_LIVE_WRITTEN;
+						dst_reg->subreg_def = DEF_NOT_SUBREG;
+					} else {
+						mark_reg_unknown(env, regs, insn->dst_reg);
+					}
+				}
+			} else {
+				/* R1 = (u32) R2 */
+				if (is_pointer_value(env, insn->src_reg)) {
+					verbose(env,
+						"R%d partial copy of pointer\n",
+						insn->src_reg);
+					return -EACCES;
+				} else if (src_reg->type == SCALAR_VALUE) {
+					if (insn->off == 0) {
+						bool is_src_reg_u32 = src_reg->umax_value <= U32_MAX;
+
+						if (is_src_reg_u32 && need_id)
+							src_reg->id = ++env->id_gen;
+						copy_register_state(dst_reg, src_reg);
+						/* Make sure ID is cleared if src_reg is not in u32
+						 * range otherwise dst_reg min/max could be incorrectly
+						 * propagated into src_reg by find_equal_scalars()
+						 */
+						if (!is_src_reg_u32)
+							dst_reg->id = 0;
+						dst_reg->live |= REG_LIVE_WRITTEN;
+						dst_reg->subreg_def = env->insn_idx + 1;
+					} else {
+						/* case: W1 = (s8, s16)W2 */
+						bool no_sext = src_reg->umax_value < (1ULL << (insn->off - 1));
+
+						if (no_sext && need_id)
+							src_reg->id = ++env->id_gen;
+						copy_register_state(dst_reg, src_reg);
+						if (!no_sext)
+							dst_reg->id = 0;
+						dst_reg->live |= REG_LIVE_WRITTEN;
+						dst_reg->subreg_def = env->insn_idx + 1;
+						coerce_subreg_to_size_sx(dst_reg, insn->off >> 3);
+					}
+				} else {
+					mark_reg_unknown(env, regs,
+							 insn->dst_reg);
+				}
+				zext_32_to_64(dst_reg);
+				reg_bounds_sync(dst_reg);
+			}
+		} else {
+			/* case: R = imm
+			 * remember the value we stored into this reg
+			 */
+			/* clear any state __mark_reg_known doesn't set */
+			mark_reg_unknown(env, regs, insn->dst_reg);
+			regs[insn->dst_reg].type = SCALAR_VALUE;
+			if (BPF_CLASS(insn->code) == BPF_ALU64) {
+				__mark_reg_known(regs + insn->dst_reg,
+						 insn->imm);
+			} else {
+				__mark_reg_known(regs + insn->dst_reg,
+						 (u32)insn->imm);
+			}
+		}
+
+	} else if (opcode > BPF_END) {
+		verbose(env, "invalid BPF_ALU opcode %x\n", opcode);
+		return -EINVAL;
+
+	} else {	/* all other ALU ops: and, sub, xor, add, ... */
+
+		if (BPF_SRC(insn->code) == BPF_X) {
+			if (insn->imm != 0 || insn->off > 1 ||
+			    (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) {
+				verbose(env, "BPF_ALU uses reserved fields\n");
+				return -EINVAL;
+			}
+			/* check src1 operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+		} else {
+			if (insn->src_reg != BPF_REG_0 || insn->off > 1 ||
+			    (insn->off == 1 && opcode != BPF_MOD && opcode != BPF_DIV)) {
+				verbose(env, "BPF_ALU uses reserved fields\n");
+				return -EINVAL;
+			}
+		}
+
+		/* check src2 operand */
+		err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+		if (err)
+			return err;
+
+		if ((opcode == BPF_MOD || opcode == BPF_DIV) &&
+		    BPF_SRC(insn->code) == BPF_K && insn->imm == 0) {
+			verbose(env, "div by zero\n");
+			return -EINVAL;
+		}
+
+		if ((opcode == BPF_LSH || opcode == BPF_RSH ||
+		     opcode == BPF_ARSH) && BPF_SRC(insn->code) == BPF_K) {
+			int size = BPF_CLASS(insn->code) == BPF_ALU64 ? 64 : 32;
+
+			if (insn->imm < 0 || insn->imm >= size) {
+				verbose(env, "invalid shift %d\n", insn->imm);
+				return -EINVAL;
+			}
+		}
+
+		/* check dest operand */
+		err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+		if (err)
+			return err;
+
+		return adjust_reg_min_max_vals(env, insn);
+	}
+
+	return 0;
+}
+
+static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
+				   struct bpf_reg_state *dst_reg,
+				   enum bpf_reg_type type,
+				   bool range_right_open)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+	int new_range;
+
+	if (dst_reg->off < 0 ||
+	    (dst_reg->off == 0 && range_right_open))
+		/* This doesn't give us any range */
+		return;
+
+	if (dst_reg->umax_value > MAX_PACKET_OFF ||
+	    dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF)
+		/* Risk of overflow.  For instance, ptr + (1<<63) may be less
+		 * than pkt_end, but that's because it's also less than pkt.
+		 */
+		return;
+
+	new_range = dst_reg->off;
+	if (range_right_open)
+		new_range++;
+
+	/* Examples for register markings:
+	 *
+	 * pkt_data in dst register:
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (r2 > pkt_end) goto <handle exception>
+	 *   <access okay>
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (r2 < pkt_end) goto <access okay>
+	 *   <handle exception>
+	 *
+	 *   Where:
+	 *     r2 == dst_reg, pkt_end == src_reg
+	 *     r2=pkt(id=n,off=8,r=0)
+	 *     r3=pkt(id=n,off=0,r=0)
+	 *
+	 * pkt_data in src register:
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (pkt_end >= r2) goto <access okay>
+	 *   <handle exception>
+	 *
+	 *   r2 = r3;
+	 *   r2 += 8;
+	 *   if (pkt_end <= r2) goto <handle exception>
+	 *   <access okay>
+	 *
+	 *   Where:
+	 *     pkt_end == dst_reg, r2 == src_reg
+	 *     r2=pkt(id=n,off=8,r=0)
+	 *     r3=pkt(id=n,off=0,r=0)
+	 *
+	 * Find register r3 and mark its range as r3=pkt(id=n,off=0,r=8)
+	 * or r3=pkt(id=n,off=0,r=8-1), so that range of bytes [r3, r3 + 8)
+	 * and [r3, r3 + 8-1) respectively is safe to access depending on
+	 * the check.
+	 */
+
+	/* If our ids match, then we must have the same max_value.  And we
+	 * don't care about the other reg's fixed offset, since if it's too big
+	 * the range won't allow anything.
+	 * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
+	 */
+	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+		if (reg->type == type && reg->id == dst_reg->id)
+			/* keep the maximum range already checked */
+			reg->range = max(reg->range, new_range);
+	}));
+}
+
+static int is_branch32_taken(struct bpf_reg_state *reg, u32 val, u8 opcode)
+{
+	struct tnum subreg = tnum_subreg(reg->var_off);
+	s32 sval = (s32)val;
+
+	switch (opcode) {
+	case BPF_JEQ:
+		if (tnum_is_const(subreg))
+			return !!tnum_equals_const(subreg, val);
+		else if (val < reg->u32_min_value || val > reg->u32_max_value)
+			return 0;
+		break;
+	case BPF_JNE:
+		if (tnum_is_const(subreg))
+			return !tnum_equals_const(subreg, val);
+		else if (val < reg->u32_min_value || val > reg->u32_max_value)
+			return 1;
+		break;
+	case BPF_JSET:
+		if ((~subreg.mask & subreg.value) & val)
+			return 1;
+		if (!((subreg.mask | subreg.value) & val))
+			return 0;
+		break;
+	case BPF_JGT:
+		if (reg->u32_min_value > val)
+			return 1;
+		else if (reg->u32_max_value <= val)
+			return 0;
+		break;
+	case BPF_JSGT:
+		if (reg->s32_min_value > sval)
+			return 1;
+		else if (reg->s32_max_value <= sval)
+			return 0;
+		break;
+	case BPF_JLT:
+		if (reg->u32_max_value < val)
+			return 1;
+		else if (reg->u32_min_value >= val)
+			return 0;
+		break;
+	case BPF_JSLT:
+		if (reg->s32_max_value < sval)
+			return 1;
+		else if (reg->s32_min_value >= sval)
+			return 0;
+		break;
+	case BPF_JGE:
+		if (reg->u32_min_value >= val)
+			return 1;
+		else if (reg->u32_max_value < val)
+			return 0;
+		break;
+	case BPF_JSGE:
+		if (reg->s32_min_value >= sval)
+			return 1;
+		else if (reg->s32_max_value < sval)
+			return 0;
+		break;
+	case BPF_JLE:
+		if (reg->u32_max_value <= val)
+			return 1;
+		else if (reg->u32_min_value > val)
+			return 0;
+		break;
+	case BPF_JSLE:
+		if (reg->s32_max_value <= sval)
+			return 1;
+		else if (reg->s32_min_value > sval)
+			return 0;
+		break;
+	}
+
+	return -1;
+}
+
+
+static int is_branch64_taken(struct bpf_reg_state *reg, u64 val, u8 opcode)
+{
+	s64 sval = (s64)val;
+
+	switch (opcode) {
+	case BPF_JEQ:
+		if (tnum_is_const(reg->var_off))
+			return !!tnum_equals_const(reg->var_off, val);
+		else if (val < reg->umin_value || val > reg->umax_value)
+			return 0;
+		break;
+	case BPF_JNE:
+		if (tnum_is_const(reg->var_off))
+			return !tnum_equals_const(reg->var_off, val);
+		else if (val < reg->umin_value || val > reg->umax_value)
+			return 1;
+		break;
+	case BPF_JSET:
+		if ((~reg->var_off.mask & reg->var_off.value) & val)
+			return 1;
+		if (!((reg->var_off.mask | reg->var_off.value) & val))
+			return 0;
+		break;
+	case BPF_JGT:
+		if (reg->umin_value > val)
+			return 1;
+		else if (reg->umax_value <= val)
+			return 0;
+		break;
+	case BPF_JSGT:
+		if (reg->smin_value > sval)
+			return 1;
+		else if (reg->smax_value <= sval)
+			return 0;
+		break;
+	case BPF_JLT:
+		if (reg->umax_value < val)
+			return 1;
+		else if (reg->umin_value >= val)
+			return 0;
+		break;
+	case BPF_JSLT:
+		if (reg->smax_value < sval)
+			return 1;
+		else if (reg->smin_value >= sval)
+			return 0;
+		break;
+	case BPF_JGE:
+		if (reg->umin_value >= val)
+			return 1;
+		else if (reg->umax_value < val)
+			return 0;
+		break;
+	case BPF_JSGE:
+		if (reg->smin_value >= sval)
+			return 1;
+		else if (reg->smax_value < sval)
+			return 0;
+		break;
+	case BPF_JLE:
+		if (reg->umax_value <= val)
+			return 1;
+		else if (reg->umin_value > val)
+			return 0;
+		break;
+	case BPF_JSLE:
+		if (reg->smax_value <= sval)
+			return 1;
+		else if (reg->smin_value > sval)
+			return 0;
+		break;
+	}
+
+	return -1;
+}
+
+/* compute branch direction of the expression "if (reg opcode val) goto target;"
+ * and return:
+ *  1 - branch will be taken and "goto target" will be executed
+ *  0 - branch will not be taken and fall-through to next insn
+ * -1 - unknown. Example: "if (reg < 5)" is unknown when register value
+ *      range [0,10]
+ */
+static int is_branch_taken(struct bpf_reg_state *reg, u64 val, u8 opcode,
+			   bool is_jmp32)
+{
+	if (__is_pointer_value(false, reg)) {
+		if (!reg_not_null(reg))
+			return -1;
+
+		/* If pointer is valid tests against zero will fail so we can
+		 * use this to direct branch taken.
+		 */
+		if (val != 0)
+			return -1;
+
+		switch (opcode) {
+		case BPF_JEQ:
+			return 0;
+		case BPF_JNE:
+			return 1;
+		default:
+			return -1;
+		}
+	}
+
+	if (is_jmp32)
+		return is_branch32_taken(reg, val, opcode);
+	return is_branch64_taken(reg, val, opcode);
+}
+
+static int flip_opcode(u32 opcode)
+{
+	/* How can we transform "a <op> b" into "b <op> a"? */
+	static const u8 opcode_flip[16] = {
+		/* these stay the same */
+		[BPF_JEQ  >> 4] = BPF_JEQ,
+		[BPF_JNE  >> 4] = BPF_JNE,
+		[BPF_JSET >> 4] = BPF_JSET,
+		/* these swap "lesser" and "greater" (L and G in the opcodes) */
+		[BPF_JGE  >> 4] = BPF_JLE,
+		[BPF_JGT  >> 4] = BPF_JLT,
+		[BPF_JLE  >> 4] = BPF_JGE,
+		[BPF_JLT  >> 4] = BPF_JGT,
+		[BPF_JSGE >> 4] = BPF_JSLE,
+		[BPF_JSGT >> 4] = BPF_JSLT,
+		[BPF_JSLE >> 4] = BPF_JSGE,
+		[BPF_JSLT >> 4] = BPF_JSGT
+	};
+	return opcode_flip[opcode >> 4];
+}
+
+static int is_pkt_ptr_branch_taken(struct bpf_reg_state *dst_reg,
+				   struct bpf_reg_state *src_reg,
+				   u8 opcode)
+{
+	struct bpf_reg_state *pkt;
+
+	if (src_reg->type == PTR_TO_PACKET_END) {
+		pkt = dst_reg;
+	} else if (dst_reg->type == PTR_TO_PACKET_END) {
+		pkt = src_reg;
+		opcode = flip_opcode(opcode);
+	} else {
+		return -1;
+	}
+
+	if (pkt->range >= 0)
+		return -1;
+
+	switch (opcode) {
+	case BPF_JLE:
+		/* pkt <= pkt_end */
+		fallthrough;
+	case BPF_JGT:
+		/* pkt > pkt_end */
+		if (pkt->range == BEYOND_PKT_END)
+			/* pkt has at last one extra byte beyond pkt_end */
+			return opcode == BPF_JGT;
+		break;
+	case BPF_JLT:
+		/* pkt < pkt_end */
+		fallthrough;
+	case BPF_JGE:
+		/* pkt >= pkt_end */
+		if (pkt->range == BEYOND_PKT_END || pkt->range == AT_PKT_END)
+			return opcode == BPF_JGE;
+		break;
+	}
+	return -1;
+}
+
+/* Adjusts the register min/max values in the case that the dst_reg is the
+ * variable register that we are working on, and src_reg is a constant or we're
+ * simply doing a BPF_K check.
+ * In JEQ/JNE cases we also adjust the var_off values.
+ */
+static void reg_set_min_max(struct bpf_reg_state *true_reg,
+			    struct bpf_reg_state *false_reg,
+			    u64 val, u32 val32,
+			    u8 opcode, bool is_jmp32)
+{
+	struct tnum false_32off = tnum_subreg(false_reg->var_off);
+	struct tnum false_64off = false_reg->var_off;
+	struct tnum true_32off = tnum_subreg(true_reg->var_off);
+	struct tnum true_64off = true_reg->var_off;
+	s64 sval = (s64)val;
+	s32 sval32 = (s32)val32;
+
+	/* If the dst_reg is a pointer, we can't learn anything about its
+	 * variable offset from the compare (unless src_reg were a pointer into
+	 * the same object, but we don't bother with that.
+	 * Since false_reg and true_reg have the same type by construction, we
+	 * only need to check one of them for pointerness.
+	 */
+	if (__is_pointer_value(false, false_reg))
+		return;
+
+	switch (opcode) {
+	/* JEQ/JNE comparison doesn't change the register equivalence.
+	 *
+	 * r1 = r2;
+	 * if (r1 == 42) goto label;
+	 * ...
+	 * label: // here both r1 and r2 are known to be 42.
+	 *
+	 * Hence when marking register as known preserve it's ID.
+	 */
+	case BPF_JEQ:
+		if (is_jmp32) {
+			__mark_reg32_known(true_reg, val32);
+			true_32off = tnum_subreg(true_reg->var_off);
+		} else {
+			___mark_reg_known(true_reg, val);
+			true_64off = true_reg->var_off;
+		}
+		break;
+	case BPF_JNE:
+		if (is_jmp32) {
+			__mark_reg32_known(false_reg, val32);
+			false_32off = tnum_subreg(false_reg->var_off);
+		} else {
+			___mark_reg_known(false_reg, val);
+			false_64off = false_reg->var_off;
+		}
+		break;
+	case BPF_JSET:
+		if (is_jmp32) {
+			false_32off = tnum_and(false_32off, tnum_const(~val32));
+			if (is_power_of_2(val32))
+				true_32off = tnum_or(true_32off,
+						     tnum_const(val32));
+		} else {
+			false_64off = tnum_and(false_64off, tnum_const(~val));
+			if (is_power_of_2(val))
+				true_64off = tnum_or(true_64off,
+						     tnum_const(val));
+		}
+		break;
+	case BPF_JGE:
+	case BPF_JGT:
+	{
+		if (is_jmp32) {
+			u32 false_umax = opcode == BPF_JGT ? val32  : val32 - 1;
+			u32 true_umin = opcode == BPF_JGT ? val32 + 1 : val32;
+
+			false_reg->u32_max_value = min(false_reg->u32_max_value,
+						       false_umax);
+			true_reg->u32_min_value = max(true_reg->u32_min_value,
+						      true_umin);
+		} else {
+			u64 false_umax = opcode == BPF_JGT ? val    : val - 1;
+			u64 true_umin = opcode == BPF_JGT ? val + 1 : val;
+
+			false_reg->umax_value = min(false_reg->umax_value, false_umax);
+			true_reg->umin_value = max(true_reg->umin_value, true_umin);
+		}
+		break;
+	}
+	case BPF_JSGE:
+	case BPF_JSGT:
+	{
+		if (is_jmp32) {
+			s32 false_smax = opcode == BPF_JSGT ? sval32    : sval32 - 1;
+			s32 true_smin = opcode == BPF_JSGT ? sval32 + 1 : sval32;
+
+			false_reg->s32_max_value = min(false_reg->s32_max_value, false_smax);
+			true_reg->s32_min_value = max(true_reg->s32_min_value, true_smin);
+		} else {
+			s64 false_smax = opcode == BPF_JSGT ? sval    : sval - 1;
+			s64 true_smin = opcode == BPF_JSGT ? sval + 1 : sval;
+
+			false_reg->smax_value = min(false_reg->smax_value, false_smax);
+			true_reg->smin_value = max(true_reg->smin_value, true_smin);
+		}
+		break;
+	}
+	case BPF_JLE:
+	case BPF_JLT:
+	{
+		if (is_jmp32) {
+			u32 false_umin = opcode == BPF_JLT ? val32  : val32 + 1;
+			u32 true_umax = opcode == BPF_JLT ? val32 - 1 : val32;
+
+			false_reg->u32_min_value = max(false_reg->u32_min_value,
+						       false_umin);
+			true_reg->u32_max_value = min(true_reg->u32_max_value,
+						      true_umax);
+		} else {
+			u64 false_umin = opcode == BPF_JLT ? val    : val + 1;
+			u64 true_umax = opcode == BPF_JLT ? val - 1 : val;
+
+			false_reg->umin_value = max(false_reg->umin_value, false_umin);
+			true_reg->umax_value = min(true_reg->umax_value, true_umax);
+		}
+		break;
+	}
+	case BPF_JSLE:
+	case BPF_JSLT:
+	{
+		if (is_jmp32) {
+			s32 false_smin = opcode == BPF_JSLT ? sval32    : sval32 + 1;
+			s32 true_smax = opcode == BPF_JSLT ? sval32 - 1 : sval32;
+
+			false_reg->s32_min_value = max(false_reg->s32_min_value, false_smin);
+			true_reg->s32_max_value = min(true_reg->s32_max_value, true_smax);
+		} else {
+			s64 false_smin = opcode == BPF_JSLT ? sval    : sval + 1;
+			s64 true_smax = opcode == BPF_JSLT ? sval - 1 : sval;
+
+			false_reg->smin_value = max(false_reg->smin_value, false_smin);
+			true_reg->smax_value = min(true_reg->smax_value, true_smax);
+		}
+		break;
+	}
+	default:
+		return;
+	}
+
+	if (is_jmp32) {
+		false_reg->var_off = tnum_or(tnum_clear_subreg(false_64off),
+					     tnum_subreg(false_32off));
+		true_reg->var_off = tnum_or(tnum_clear_subreg(true_64off),
+					    tnum_subreg(true_32off));
+		__reg_combine_32_into_64(false_reg);
+		__reg_combine_32_into_64(true_reg);
+	} else {
+		false_reg->var_off = false_64off;
+		true_reg->var_off = true_64off;
+		__reg_combine_64_into_32(false_reg);
+		__reg_combine_64_into_32(true_reg);
+	}
+}
+
+/* Same as above, but for the case that dst_reg holds a constant and src_reg is
+ * the variable reg.
+ */
+static void reg_set_min_max_inv(struct bpf_reg_state *true_reg,
+				struct bpf_reg_state *false_reg,
+				u64 val, u32 val32,
+				u8 opcode, bool is_jmp32)
+{
+	opcode = flip_opcode(opcode);
+	/* This uses zero as "not present in table"; luckily the zero opcode,
+	 * BPF_JA, can't get here.
+	 */
+	if (opcode)
+		reg_set_min_max(true_reg, false_reg, val, val32, opcode, is_jmp32);
+}
+
+/* Regs are known to be equal, so intersect their min/max/var_off */
+static void __reg_combine_min_max(struct bpf_reg_state *src_reg,
+				  struct bpf_reg_state *dst_reg)
+{
+	src_reg->umin_value = dst_reg->umin_value = max(src_reg->umin_value,
+							dst_reg->umin_value);
+	src_reg->umax_value = dst_reg->umax_value = min(src_reg->umax_value,
+							dst_reg->umax_value);
+	src_reg->smin_value = dst_reg->smin_value = max(src_reg->smin_value,
+							dst_reg->smin_value);
+	src_reg->smax_value = dst_reg->smax_value = min(src_reg->smax_value,
+							dst_reg->smax_value);
+	src_reg->var_off = dst_reg->var_off = tnum_intersect(src_reg->var_off,
+							     dst_reg->var_off);
+	reg_bounds_sync(src_reg);
+	reg_bounds_sync(dst_reg);
+}
+
+static void reg_combine_min_max(struct bpf_reg_state *true_src,
+				struct bpf_reg_state *true_dst,
+				struct bpf_reg_state *false_src,
+				struct bpf_reg_state *false_dst,
+				u8 opcode)
+{
+	switch (opcode) {
+	case BPF_JEQ:
+		__reg_combine_min_max(true_src, true_dst);
+		break;
+	case BPF_JNE:
+		__reg_combine_min_max(false_src, false_dst);
+		break;
+	}
+}
+
+static void mark_ptr_or_null_reg(struct bpf_func_state *state,
+				 struct bpf_reg_state *reg, u32 id,
+				 bool is_null)
+{
+	if (type_may_be_null(reg->type) && reg->id == id &&
+	    (is_rcu_reg(reg) || !WARN_ON_ONCE(!reg->id))) {
+		/* 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 (!(type_is_ptr_alloc_obj(reg->type) || type_is_non_owning_ref(reg->type)) &&
+		    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
+			 * onwards anymore, thus we should better reset it,
+			 * so that state pruning has chances to take effect.
+			 */
+			reg->id = 0;
+			reg->ref_obj_id = 0;
+
+			return;
+		}
+
+		mark_ptr_not_null_reg(reg);
+
+		if (!reg_may_point_to_spin_lock(reg)) {
+			/* For not-NULL ptr, reg->ref_obj_id will be reset
+			 * in release_reference().
+			 *
+			 * reg->id is still used by spin_lock ptr. Other
+			 * than spin_lock ptr type, reg->id can be reset.
+			 */
+			reg->id = 0;
+		}
+	}
+}
+
+/* The logic is similar to find_good_pkt_pointers(), both could eventually
+ * be folded together at some point.
+ */
+static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
+				  bool is_null)
+{
+	struct bpf_func_state *state = vstate->frame[vstate->curframe];
+	struct bpf_reg_state *regs = state->regs, *reg;
+	u32 ref_obj_id = regs[regno].ref_obj_id;
+	u32 id = regs[regno].id;
+
+	if (ref_obj_id && ref_obj_id == id && is_null)
+		/* regs[regno] is in the " == NULL" branch.
+		 * No one could have freed the reference state before
+		 * doing the NULL check.
+		 */
+		WARN_ON_ONCE(release_reference_state(state, id));
+
+	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+		mark_ptr_or_null_reg(state, reg, id, is_null);
+	}));
+}
+
+static bool try_match_pkt_pointers(const struct bpf_insn *insn,
+				   struct bpf_reg_state *dst_reg,
+				   struct bpf_reg_state *src_reg,
+				   struct bpf_verifier_state *this_branch,
+				   struct bpf_verifier_state *other_branch)
+{
+	if (BPF_SRC(insn->code) != BPF_X)
+		return false;
+
+	/* Pointers are always 64-bit. */
+	if (BPF_CLASS(insn->code) == BPF_JMP32)
+		return false;
+
+	switch (BPF_OP(insn->code)) {
+	case BPF_JGT:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' > pkt_end, pkt_meta' > pkt_data */
+			find_good_pkt_pointers(this_branch, dst_reg,
+					       dst_reg->type, false);
+			mark_pkt_end(other_branch, insn->dst_reg, true);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end > pkt_data', pkt_data > pkt_meta' */
+			find_good_pkt_pointers(other_branch, src_reg,
+					       src_reg->type, true);
+			mark_pkt_end(this_branch, insn->src_reg, false);
+		} else {
+			return false;
+		}
+		break;
+	case BPF_JLT:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' < pkt_end, pkt_meta' < pkt_data */
+			find_good_pkt_pointers(other_branch, dst_reg,
+					       dst_reg->type, true);
+			mark_pkt_end(this_branch, insn->dst_reg, false);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end < pkt_data', pkt_data > pkt_meta' */
+			find_good_pkt_pointers(this_branch, src_reg,
+					       src_reg->type, false);
+			mark_pkt_end(other_branch, insn->src_reg, true);
+		} else {
+			return false;
+		}
+		break;
+	case BPF_JGE:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
+			find_good_pkt_pointers(this_branch, dst_reg,
+					       dst_reg->type, true);
+			mark_pkt_end(other_branch, insn->dst_reg, false);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
+			find_good_pkt_pointers(other_branch, src_reg,
+					       src_reg->type, false);
+			mark_pkt_end(this_branch, insn->src_reg, true);
+		} else {
+			return false;
+		}
+		break;
+	case BPF_JLE:
+		if ((dst_reg->type == PTR_TO_PACKET &&
+		     src_reg->type == PTR_TO_PACKET_END) ||
+		    (dst_reg->type == PTR_TO_PACKET_META &&
+		     reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
+			/* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
+			find_good_pkt_pointers(other_branch, dst_reg,
+					       dst_reg->type, false);
+			mark_pkt_end(this_branch, insn->dst_reg, true);
+		} else if ((dst_reg->type == PTR_TO_PACKET_END &&
+			    src_reg->type == PTR_TO_PACKET) ||
+			   (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
+			    src_reg->type == PTR_TO_PACKET_META)) {
+			/* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
+			find_good_pkt_pointers(this_branch, src_reg,
+					       src_reg->type, true);
+			mark_pkt_end(other_branch, insn->src_reg, false);
+		} else {
+			return false;
+		}
+		break;
+	default:
+		return false;
+	}
+
+	return true;
+}
+
+static void find_equal_scalars(struct bpf_verifier_state *vstate,
+			       struct bpf_reg_state *known_reg)
+{
+	struct bpf_func_state *state;
+	struct bpf_reg_state *reg;
+
+	bpf_for_each_reg_in_vstate(vstate, state, reg, ({
+		if (reg->type == SCALAR_VALUE && reg->id == known_reg->id)
+			copy_register_state(reg, known_reg);
+	}));
+}
+
+static int check_cond_jmp_op(struct bpf_verifier_env *env,
+			     struct bpf_insn *insn, int *insn_idx)
+{
+	struct bpf_verifier_state *this_branch = env->cur_state;
+	struct bpf_verifier_state *other_branch;
+	struct bpf_reg_state *regs = this_branch->frame[this_branch->curframe]->regs;
+	struct bpf_reg_state *dst_reg, *other_branch_regs, *src_reg = NULL;
+	struct bpf_reg_state *eq_branch_regs;
+	u8 opcode = BPF_OP(insn->code);
+	bool is_jmp32;
+	int pred = -1;
+	int err;
+
+	/* Only conditional jumps are expected to reach here. */
+	if (opcode == BPF_JA || opcode > BPF_JSLE) {
+		verbose(env, "invalid BPF_JMP/JMP32 opcode %x\n", opcode);
+		return -EINVAL;
+	}
+
+	/* check src2 operand */
+	err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+	if (err)
+		return err;
+
+	dst_reg = &regs[insn->dst_reg];
+	if (BPF_SRC(insn->code) == BPF_X) {
+		if (insn->imm != 0) {
+			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
+			return -EINVAL;
+		}
+
+		/* check src1 operand */
+		err = check_reg_arg(env, insn->src_reg, SRC_OP);
+		if (err)
+			return err;
+
+		src_reg = &regs[insn->src_reg];
+		if (!(reg_is_pkt_pointer_any(dst_reg) && reg_is_pkt_pointer_any(src_reg)) &&
+		    is_pointer_value(env, insn->src_reg)) {
+			verbose(env, "R%d pointer comparison prohibited\n",
+				insn->src_reg);
+			return -EACCES;
+		}
+	} else {
+		if (insn->src_reg != BPF_REG_0) {
+			verbose(env, "BPF_JMP/JMP32 uses reserved fields\n");
+			return -EINVAL;
+		}
+	}
+
+	is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
+
+	if (BPF_SRC(insn->code) == BPF_K) {
+		pred = is_branch_taken(dst_reg, insn->imm, opcode, is_jmp32);
+	} else if (src_reg->type == SCALAR_VALUE &&
+		   is_jmp32 && tnum_is_const(tnum_subreg(src_reg->var_off))) {
+		pred = is_branch_taken(dst_reg,
+				       tnum_subreg(src_reg->var_off).value,
+				       opcode,
+				       is_jmp32);
+	} else if (src_reg->type == SCALAR_VALUE &&
+		   !is_jmp32 && tnum_is_const(src_reg->var_off)) {
+		pred = is_branch_taken(dst_reg,
+				       src_reg->var_off.value,
+				       opcode,
+				       is_jmp32);
+	} else if (dst_reg->type == SCALAR_VALUE &&
+		   is_jmp32 && tnum_is_const(tnum_subreg(dst_reg->var_off))) {
+		pred = is_branch_taken(src_reg,
+				       tnum_subreg(dst_reg->var_off).value,
+				       flip_opcode(opcode),
+				       is_jmp32);
+	} else if (dst_reg->type == SCALAR_VALUE &&
+		   !is_jmp32 && tnum_is_const(dst_reg->var_off)) {
+		pred = is_branch_taken(src_reg,
+				       dst_reg->var_off.value,
+				       flip_opcode(opcode),
+				       is_jmp32);
+	} else if (reg_is_pkt_pointer_any(dst_reg) &&
+		   reg_is_pkt_pointer_any(src_reg) &&
+		   !is_jmp32) {
+		pred = is_pkt_ptr_branch_taken(dst_reg, src_reg, opcode);
+	}
+
+	if (pred >= 0) {
+		/* If we get here with a dst_reg pointer type it is because
+		 * above is_branch_taken() special cased the 0 comparison.
+		 */
+		if (!__is_pointer_value(false, dst_reg))
+			err = mark_chain_precision(env, insn->dst_reg);
+		if (BPF_SRC(insn->code) == BPF_X && !err &&
+		    !__is_pointer_value(false, src_reg))
+			err = mark_chain_precision(env, insn->src_reg);
+		if (err)
+			return err;
+	}
+
+	if (pred == 1) {
+		/* Only follow the goto, ignore fall-through. If needed, push
+		 * the fall-through branch for simulation under speculative
+		 * execution.
+		 */
+		if (!env->bypass_spec_v1 &&
+		    !sanitize_speculative_path(env, insn, *insn_idx + 1,
+					       *insn_idx))
+			return -EFAULT;
+		if (env->log.level & BPF_LOG_LEVEL)
+			print_insn_state(env, this_branch->frame[this_branch->curframe]);
+		*insn_idx += insn->off;
+		return 0;
+	} else if (pred == 0) {
+		/* Only follow the fall-through branch, since that's where the
+		 * program will go. If needed, push the goto branch for
+		 * simulation under speculative execution.
+		 */
+		if (!env->bypass_spec_v1 &&
+		    !sanitize_speculative_path(env, insn,
+					       *insn_idx + insn->off + 1,
+					       *insn_idx))
+			return -EFAULT;
+		if (env->log.level & BPF_LOG_LEVEL)
+			print_insn_state(env, this_branch->frame[this_branch->curframe]);
+		return 0;
+	}
+
+	other_branch = push_stack(env, *insn_idx + insn->off + 1, *insn_idx,
+				  false);
+	if (!other_branch)
+		return -EFAULT;
+	other_branch_regs = other_branch->frame[other_branch->curframe]->regs;
+
+	/* detect if we are comparing against a constant value so we can adjust
+	 * our min/max values for our dst register.
+	 * this is only legit if both are scalars (or pointers to the same
+	 * object, I suppose, see the PTR_MAYBE_NULL related if block below),
+	 * because otherwise the different base pointers mean the offsets aren't
+	 * comparable.
+	 */
+	if (BPF_SRC(insn->code) == BPF_X) {
+		struct bpf_reg_state *src_reg = &regs[insn->src_reg];
+
+		if (dst_reg->type == SCALAR_VALUE &&
+		    src_reg->type == SCALAR_VALUE) {
+			if (tnum_is_const(src_reg->var_off) ||
+			    (is_jmp32 &&
+			     tnum_is_const(tnum_subreg(src_reg->var_off))))
+				reg_set_min_max(&other_branch_regs[insn->dst_reg],
+						dst_reg,
+						src_reg->var_off.value,
+						tnum_subreg(src_reg->var_off).value,
+						opcode, is_jmp32);
+			else if (tnum_is_const(dst_reg->var_off) ||
+				 (is_jmp32 &&
+				  tnum_is_const(tnum_subreg(dst_reg->var_off))))
+				reg_set_min_max_inv(&other_branch_regs[insn->src_reg],
+						    src_reg,
+						    dst_reg->var_off.value,
+						    tnum_subreg(dst_reg->var_off).value,
+						    opcode, is_jmp32);
+			else if (!is_jmp32 &&
+				 (opcode == BPF_JEQ || opcode == BPF_JNE))
+				/* Comparing for equality, we can combine knowledge */
+				reg_combine_min_max(&other_branch_regs[insn->src_reg],
+						    &other_branch_regs[insn->dst_reg],
+						    src_reg, dst_reg, opcode);
+			if (src_reg->id &&
+			    !WARN_ON_ONCE(src_reg->id != other_branch_regs[insn->src_reg].id)) {
+				find_equal_scalars(this_branch, src_reg);
+				find_equal_scalars(other_branch, &other_branch_regs[insn->src_reg]);
+			}
+
+		}
+	} else if (dst_reg->type == SCALAR_VALUE) {
+		reg_set_min_max(&other_branch_regs[insn->dst_reg],
+					dst_reg, insn->imm, (u32)insn->imm,
+					opcode, is_jmp32);
+	}
+
+	if (dst_reg->type == SCALAR_VALUE && dst_reg->id &&
+	    !WARN_ON_ONCE(dst_reg->id != other_branch_regs[insn->dst_reg].id)) {
+		find_equal_scalars(this_branch, dst_reg);
+		find_equal_scalars(other_branch, &other_branch_regs[insn->dst_reg]);
+	}
+
+	/* if one pointer register is compared to another pointer
+	 * register check if PTR_MAYBE_NULL could be lifted.
+	 * E.g. register A - maybe null
+	 *      register B - not null
+	 * for JNE A, B, ... - A is not null in the false branch;
+	 * for JEQ A, B, ... - A is not null in the true branch.
+	 *
+	 * Since PTR_TO_BTF_ID points to a kernel struct that does
+	 * not need to be null checked by the BPF program, i.e.,
+	 * could be null even without PTR_MAYBE_NULL marking, so
+	 * only propagate nullness when neither reg is that type.
+	 */
+	if (!is_jmp32 && BPF_SRC(insn->code) == BPF_X &&
+	    __is_pointer_value(false, src_reg) && __is_pointer_value(false, dst_reg) &&
+	    type_may_be_null(src_reg->type) != type_may_be_null(dst_reg->type) &&
+	    base_type(src_reg->type) != PTR_TO_BTF_ID &&
+	    base_type(dst_reg->type) != PTR_TO_BTF_ID) {
+		eq_branch_regs = NULL;
+		switch (opcode) {
+		case BPF_JEQ:
+			eq_branch_regs = other_branch_regs;
+			break;
+		case BPF_JNE:
+			eq_branch_regs = regs;
+			break;
+		default:
+			/* do nothing */
+			break;
+		}
+		if (eq_branch_regs) {
+			if (type_may_be_null(src_reg->type))
+				mark_ptr_not_null_reg(&eq_branch_regs[insn->src_reg]);
+			else
+				mark_ptr_not_null_reg(&eq_branch_regs[insn->dst_reg]);
+		}
+	}
+
+	/* detect if R == 0 where R is returned from bpf_map_lookup_elem().
+	 * NOTE: these optimizations below are related with pointer comparison
+	 *       which will never be JMP32.
+	 */
+	if (!is_jmp32 && BPF_SRC(insn->code) == BPF_K &&
+	    insn->imm == 0 && (opcode == BPF_JEQ || opcode == BPF_JNE) &&
+	    type_may_be_null(dst_reg->type)) {
+		/* Mark all identical registers in each branch as either
+		 * safe or unknown depending R == 0 or R != 0 conditional.
+		 */
+		mark_ptr_or_null_regs(this_branch, insn->dst_reg,
+				      opcode == BPF_JNE);
+		mark_ptr_or_null_regs(other_branch, insn->dst_reg,
+				      opcode == BPF_JEQ);
+	} else if (!try_match_pkt_pointers(insn, dst_reg, &regs[insn->src_reg],
+					   this_branch, other_branch) &&
+		   is_pointer_value(env, insn->dst_reg)) {
+		verbose(env, "R%d pointer comparison prohibited\n",
+			insn->dst_reg);
+		return -EACCES;
+	}
+	if (env->log.level & BPF_LOG_LEVEL)
+		print_insn_state(env, this_branch->frame[this_branch->curframe]);
+	return 0;
+}
+
+/* verify BPF_LD_IMM64 instruction */
+static int check_ld_imm(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	struct bpf_insn_aux_data *aux = cur_aux(env);
+	struct bpf_reg_state *regs = cur_regs(env);
+	struct bpf_reg_state *dst_reg;
+	struct bpf_map *map;
+	int err;
+
+	if (BPF_SIZE(insn->code) != BPF_DW) {
+		verbose(env, "invalid BPF_LD_IMM insn\n");
+		return -EINVAL;
+	}
+	if (insn->off != 0) {
+		verbose(env, "BPF_LD_IMM64 uses reserved fields\n");
+		return -EINVAL;
+	}
+
+	err = check_reg_arg(env, insn->dst_reg, DST_OP);
+	if (err)
+		return err;
+
+	dst_reg = &regs[insn->dst_reg];
+	if (insn->src_reg == 0) {
+		u64 imm = ((u64)(insn + 1)->imm << 32) | (u32)insn->imm;
+
+		dst_reg->type = SCALAR_VALUE;
+		__mark_reg_known(&regs[insn->dst_reg], imm);
+		return 0;
+	}
+
+	/* All special src_reg cases are listed below. From this point onwards
+	 * we either succeed and assign a corresponding dst_reg->type after
+	 * zeroing the offset, or fail and reject the program.
+	 */
+	mark_reg_known_zero(env, regs, insn->dst_reg);
+
+	if (insn->src_reg == BPF_PSEUDO_BTF_ID) {
+		dst_reg->type = aux->btf_var.reg_type;
+		switch (base_type(dst_reg->type)) {
+		case PTR_TO_MEM:
+			dst_reg->mem_size = aux->btf_var.mem_size;
+			break;
+		case PTR_TO_BTF_ID:
+			dst_reg->btf = aux->btf_var.btf;
+			dst_reg->btf_id = aux->btf_var.btf_id;
+			break;
+		default:
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EFAULT;
+		}
+		return 0;
+	}
+
+	if (insn->src_reg == BPF_PSEUDO_FUNC) {
+		struct bpf_prog_aux *aux = env->prog->aux;
+		u32 subprogno = find_subprog(env,
+					     env->insn_idx + insn->imm + 1);
+
+		if (!aux->func_info) {
+			verbose(env, "missing btf func_info\n");
+			return -EINVAL;
+		}
+		if (aux->func_info_aux[subprogno].linkage != BTF_FUNC_STATIC) {
+			verbose(env, "callback function not static\n");
+			return -EINVAL;
+		}
+
+		dst_reg->type = PTR_TO_FUNC;
+		dst_reg->subprogno = subprogno;
+		return 0;
+	}
+
+	map = env->used_maps[aux->map_index];
+	dst_reg->map_ptr = map;
+
+	if (insn->src_reg == BPF_PSEUDO_MAP_VALUE ||
+	    insn->src_reg == BPF_PSEUDO_MAP_IDX_VALUE) {
+		dst_reg->type = PTR_TO_MAP_VALUE;
+		dst_reg->off = aux->map_off;
+		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;
+	} else {
+		verbose(env, "bpf verifier is misconfigured\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static bool may_access_skb(enum bpf_prog_type type)
+{
+	switch (type) {
+	case BPF_PROG_TYPE_SOCKET_FILTER:
+	case BPF_PROG_TYPE_SCHED_CLS:
+	case BPF_PROG_TYPE_SCHED_ACT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+/* verify safety of LD_ABS|LD_IND instructions:
+ * - they can only appear in the programs where ctx == skb
+ * - since they are wrappers of function calls, they scratch R1-R5 registers,
+ *   preserve R6-R9, and store return value into R0
+ *
+ * Implicit input:
+ *   ctx == skb == R6 == CTX
+ *
+ * Explicit input:
+ *   SRC == any register
+ *   IMM == 32-bit immediate
+ *
+ * Output:
+ *   R0 - 8/16/32-bit skb data converted to cpu endianness
+ */
+static int check_ld_abs(struct bpf_verifier_env *env, struct bpf_insn *insn)
+{
+	struct bpf_reg_state *regs = cur_regs(env);
+	static const int ctx_reg = BPF_REG_6;
+	u8 mode = BPF_MODE(insn->code);
+	int i, err;
+
+	if (!may_access_skb(resolve_prog_type(env->prog))) {
+		verbose(env, "BPF_LD_[ABS|IND] instructions not allowed for this program type\n");
+		return -EINVAL;
+	}
+
+	if (!env->ops->gen_ld_abs) {
+		verbose(env, "bpf verifier is misconfigured\n");
+		return -EINVAL;
+	}
+
+	if (insn->dst_reg != BPF_REG_0 || insn->off != 0 ||
+	    BPF_SIZE(insn->code) == BPF_DW ||
+	    (mode == BPF_ABS && insn->src_reg != BPF_REG_0)) {
+		verbose(env, "BPF_LD_[ABS|IND] uses reserved fields\n");
+		return -EINVAL;
+	}
+
+	/* check whether implicit source operand (register R6) is readable */
+	err = check_reg_arg(env, ctx_reg, SRC_OP);
+	if (err)
+		return err;
+
+	/* Disallow usage of BPF_LD_[ABS|IND] with reference tracking, as
+	 * gen_ld_abs() may terminate the program at runtime, leading to
+	 * reference leak.
+	 */
+	err = check_reference_leak(env);
+	if (err) {
+		verbose(env, "BPF_LD_[ABS|IND] cannot be mixed with socket references\n");
+		return err;
+	}
+
+	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 (env->cur_state->active_rcu_lock) {
+		verbose(env, "BPF_LD_[ABS|IND] cannot be used inside bpf_rcu_read_lock-ed region\n");
+		return -EINVAL;
+	}
+
+	if (regs[ctx_reg].type != PTR_TO_CTX) {
+		verbose(env,
+			"at the time of BPF_LD_ABS|IND R6 != pointer to skb\n");
+		return -EINVAL;
+	}
+
+	if (mode == BPF_IND) {
+		/* check explicit source operand */
+		err = check_reg_arg(env, insn->src_reg, SRC_OP);
+		if (err)
+			return err;
+	}
+
+	err = check_ptr_off_reg(env, &regs[ctx_reg], ctx_reg);
+	if (err < 0)
+		return err;
+
+	/* reset caller saved regs to unreadable */
+	for (i = 0; i < CALLER_SAVED_REGS; i++) {
+		mark_reg_not_init(env, regs, caller_saved[i]);
+		check_reg_arg(env, caller_saved[i], DST_OP_NO_MARK);
+	}
+
+	/* mark destination R0 register as readable, since it contains
+	 * the value fetched from the packet.
+	 * Already marked as written above.
+	 */
+	mark_reg_unknown(env, regs, BPF_REG_0);
+	/* ld_abs load up to 32-bit skb data. */
+	regs[BPF_REG_0].subreg_def = env->insn_idx + 1;
+	return 0;
+}
+
+static int check_return_code(struct bpf_verifier_env *env)
+{
+	struct tnum enforce_attach_type_range = tnum_unknown;
+	const struct bpf_prog *prog = env->prog;
+	struct bpf_reg_state *reg;
+	struct tnum range = tnum_range(0, 1), const_0 = tnum_const(0);
+	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
+	int err;
+	struct bpf_func_state *frame = env->cur_state->frame[0];
+	const bool is_subprog = frame->subprogno;
+
+	/* LSM and struct_ops func-ptr's return type could be "void" */
+	if (!is_subprog) {
+		switch (prog_type) {
+		case BPF_PROG_TYPE_LSM:
+			if (prog->expected_attach_type == BPF_LSM_CGROUP)
+				/* See below, can be 0 or 0-1 depending on hook. */
+				break;
+			fallthrough;
+		case BPF_PROG_TYPE_STRUCT_OPS:
+			if (!prog->aux->attach_func_proto->type)
+				return 0;
+			break;
+		default:
+			break;
+		}
+	}
+
+	/* eBPF calling convention is such that R0 is used
+	 * to return the value from eBPF program.
+	 * Make sure that it's readable at this time
+	 * of bpf_exit, which means that program wrote
+	 * something into it earlier
+	 */
+	err = check_reg_arg(env, BPF_REG_0, SRC_OP);
+	if (err)
+		return err;
+
+	if (is_pointer_value(env, BPF_REG_0)) {
+		verbose(env, "R0 leaks addr as return value\n");
+		return -EACCES;
+	}
+
+	reg = cur_regs(env) + BPF_REG_0;
+
+	if (frame->in_async_callback_fn) {
+		/* enforce return zero from async callbacks like timer */
+		if (reg->type != SCALAR_VALUE) {
+			verbose(env, "In async callback the register R0 is not a known value (%s)\n",
+				reg_type_str(env, reg->type));
+			return -EINVAL;
+		}
+
+		if (!tnum_in(const_0, reg->var_off)) {
+			verbose_invalid_scalar(env, reg, &const_0, "async callback", "R0");
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	if (is_subprog) {
+		if (reg->type != SCALAR_VALUE) {
+			verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n",
+				reg_type_str(env, reg->type));
+			return -EINVAL;
+		}
+		return 0;
+	}
+
+	switch (prog_type) {
+	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
+		if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
+		    env->prog->expected_attach_type == BPF_CGROUP_UDP6_RECVMSG ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET4_GETPEERNAME ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET6_GETPEERNAME ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET4_GETSOCKNAME ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET6_GETSOCKNAME)
+			range = tnum_range(1, 1);
+		if (env->prog->expected_attach_type == BPF_CGROUP_INET4_BIND ||
+		    env->prog->expected_attach_type == BPF_CGROUP_INET6_BIND)
+			range = tnum_range(0, 3);
+		break;
+	case BPF_PROG_TYPE_CGROUP_SKB:
+		if (env->prog->expected_attach_type == BPF_CGROUP_INET_EGRESS) {
+			range = tnum_range(0, 3);
+			enforce_attach_type_range = tnum_range(2, 3);
+		}
+		break;
+	case BPF_PROG_TYPE_CGROUP_SOCK:
+	case BPF_PROG_TYPE_SOCK_OPS:
+	case BPF_PROG_TYPE_CGROUP_DEVICE:
+	case BPF_PROG_TYPE_CGROUP_SYSCTL:
+	case BPF_PROG_TYPE_CGROUP_SOCKOPT:
+		break;
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+		if (!env->prog->aux->attach_btf_id)
+			return 0;
+		range = tnum_const(0);
+		break;
+	case BPF_PROG_TYPE_TRACING:
+		switch (env->prog->expected_attach_type) {
+		case BPF_TRACE_FENTRY:
+		case BPF_TRACE_FEXIT:
+			range = tnum_const(0);
+			break;
+		case BPF_TRACE_RAW_TP:
+		case BPF_MODIFY_RETURN:
+			return 0;
+		case BPF_TRACE_ITER:
+			break;
+		default:
+			return -ENOTSUPP;
+		}
+		break;
+	case BPF_PROG_TYPE_SK_LOOKUP:
+		range = tnum_range(SK_DROP, SK_PASS);
+		break;
+
+	case BPF_PROG_TYPE_LSM:
+		if (env->prog->expected_attach_type != BPF_LSM_CGROUP) {
+			/* Regular BPF_PROG_TYPE_LSM programs can return
+			 * any value.
+			 */
+			return 0;
+		}
+		if (!env->prog->aux->attach_func_proto->type) {
+			/* Make sure programs that attach to void
+			 * hooks don't try to modify return value.
+			 */
+			range = tnum_range(1, 1);
+		}
+		break;
+
+	case BPF_PROG_TYPE_NETFILTER:
+		range = tnum_range(NF_DROP, NF_ACCEPT);
+		break;
+	case BPF_PROG_TYPE_EXT:
+		/* freplace program can return anything as its return value
+		 * depends on the to-be-replaced kernel func or bpf program.
+		 */
+	default:
+		return 0;
+	}
+
+	if (reg->type != SCALAR_VALUE) {
+		verbose(env, "At program exit the register R0 is not a known value (%s)\n",
+			reg_type_str(env, reg->type));
+		return -EINVAL;
+	}
+
+	if (!tnum_in(range, reg->var_off)) {
+		verbose_invalid_scalar(env, reg, &range, "program exit", "R0");
+		if (prog->expected_attach_type == BPF_LSM_CGROUP &&
+		    prog_type == BPF_PROG_TYPE_LSM &&
+		    !prog->aux->attach_func_proto->type)
+			verbose(env, "Note, BPF_LSM_CGROUP that attach to void LSM hooks can't modify return value!\n");
+		return -EINVAL;
+	}
+
+	if (!tnum_is_unknown(enforce_attach_type_range) &&
+	    tnum_in(enforce_attach_type_range, reg->var_off))
+		env->prog->enforce_expected_attach_type = 1;
+	return 0;
+}
+
+/* non-recursive DFS pseudo code
+ * 1  procedure DFS-iterative(G,v):
+ * 2      label v as discovered
+ * 3      let S be a stack
+ * 4      S.push(v)
+ * 5      while S is not empty
+ * 6            t <- S.peek()
+ * 7            if t is what we're looking for:
+ * 8                return t
+ * 9            for all edges e in G.adjacentEdges(t) do
+ * 10               if edge e is already labelled
+ * 11                   continue with the next edge
+ * 12               w <- G.adjacentVertex(t,e)
+ * 13               if vertex w is not discovered and not explored
+ * 14                   label e as tree-edge
+ * 15                   label w as discovered
+ * 16                   S.push(w)
+ * 17                   continue at 5
+ * 18               else if vertex w is discovered
+ * 19                   label e as back-edge
+ * 20               else
+ * 21                   // vertex w is explored
+ * 22                   label e as forward- or cross-edge
+ * 23           label t as explored
+ * 24           S.pop()
+ *
+ * convention:
+ * 0x10 - discovered
+ * 0x11 - discovered and fall-through edge labelled
+ * 0x12 - discovered and fall-through and branch edges labelled
+ * 0x20 - explored
+ */
+
+enum {
+	DISCOVERED = 0x10,
+	EXPLORED = 0x20,
+	FALLTHROUGH = 1,
+	BRANCH = 2,
+};
+
+static void mark_prune_point(struct bpf_verifier_env *env, int idx)
+{
+	env->insn_aux_data[idx].prune_point = true;
+}
+
+static bool is_prune_point(struct bpf_verifier_env *env, int insn_idx)
+{
+	return env->insn_aux_data[insn_idx].prune_point;
+}
+
+static void mark_force_checkpoint(struct bpf_verifier_env *env, int idx)
+{
+	env->insn_aux_data[idx].force_checkpoint = true;
+}
+
+static bool is_force_checkpoint(struct bpf_verifier_env *env, int insn_idx)
+{
+	return env->insn_aux_data[insn_idx].force_checkpoint;
+}
+
+static void mark_calls_callback(struct bpf_verifier_env *env, int idx)
+{
+	env->insn_aux_data[idx].calls_callback = true;
+}
+
+static bool calls_callback(struct bpf_verifier_env *env, int insn_idx)
+{
+	return env->insn_aux_data[insn_idx].calls_callback;
+}
+
+enum {
+	DONE_EXPLORING = 0,
+	KEEP_EXPLORING = 1,
+};
+
+/* t, w, e - match pseudo-code above:
+ * t - index of current instruction
+ * w - next instruction
+ * e - edge
+ */
+static int push_insn(int t, int w, int e, struct bpf_verifier_env *env)
+{
+	int *insn_stack = env->cfg.insn_stack;
+	int *insn_state = env->cfg.insn_state;
+
+	if (e == FALLTHROUGH && insn_state[t] >= (DISCOVERED | FALLTHROUGH))
+		return DONE_EXPLORING;
+
+	if (e == BRANCH && insn_state[t] >= (DISCOVERED | BRANCH))
+		return DONE_EXPLORING;
+
+	if (w < 0 || w >= env->prog->len) {
+		verbose_linfo(env, t, "%d: ", t);
+		verbose(env, "jump out of range from insn %d to %d\n", t, w);
+		return -EINVAL;
+	}
+
+	if (e == BRANCH) {
+		/* mark branch target for state pruning */
+		mark_prune_point(env, w);
+		mark_jmp_point(env, w);
+	}
+
+	if (insn_state[w] == 0) {
+		/* tree-edge */
+		insn_state[t] = DISCOVERED | e;
+		insn_state[w] = DISCOVERED;
+		if (env->cfg.cur_stack >= env->prog->len)
+			return -E2BIG;
+		insn_stack[env->cfg.cur_stack++] = w;
+		return KEEP_EXPLORING;
+	} else if ((insn_state[w] & 0xF0) == DISCOVERED) {
+		if (env->bpf_capable)
+			return DONE_EXPLORING;
+		verbose_linfo(env, t, "%d: ", t);
+		verbose_linfo(env, w, "%d: ", w);
+		verbose(env, "back-edge from insn %d to %d\n", t, w);
+		return -EINVAL;
+	} else if (insn_state[w] == EXPLORED) {
+		/* forward- or cross-edge */
+		insn_state[t] = DISCOVERED | e;
+	} else {
+		verbose(env, "insn state internal bug\n");
+		return -EFAULT;
+	}
+	return DONE_EXPLORING;
+}
+
+static int visit_func_call_insn(int t, struct bpf_insn *insns,
+				struct bpf_verifier_env *env,
+				bool visit_callee)
+{
+	int ret, insn_sz;
+
+	insn_sz = bpf_is_ldimm64(&insns[t]) ? 2 : 1;
+	ret = push_insn(t, t + insn_sz, FALLTHROUGH, env);
+	if (ret)
+		return ret;
+
+	mark_prune_point(env, t + insn_sz);
+	/* when we exit from subprog, we need to record non-linear history */
+	mark_jmp_point(env, t + insn_sz);
+
+	if (visit_callee) {
+		mark_prune_point(env, t);
+		ret = push_insn(t, t + insns[t].imm + 1, BRANCH, env);
+	}
+	return ret;
+}
+
+/* Visits the instruction at index t and returns one of the following:
+ *  < 0 - an error occurred
+ *  DONE_EXPLORING - the instruction was fully explored
+ *  KEEP_EXPLORING - there is still work to be done before it is fully explored
+ */
+static int visit_insn(int t, struct bpf_verifier_env *env)
+{
+	struct bpf_insn *insns = env->prog->insnsi, *insn = &insns[t];
+	int ret, off, insn_sz;
+
+	if (bpf_pseudo_func(insn))
+		return visit_func_call_insn(t, insns, env, true);
+
+	/* All non-branch instructions have a single fall-through edge. */
+	if (BPF_CLASS(insn->code) != BPF_JMP &&
+	    BPF_CLASS(insn->code) != BPF_JMP32) {
+		insn_sz = bpf_is_ldimm64(insn) ? 2 : 1;
+		return push_insn(t, t + insn_sz, FALLTHROUGH, env);
+	}
+
+	switch (BPF_OP(insn->code)) {
+	case BPF_EXIT:
+		return DONE_EXPLORING;
+
+	case BPF_CALL:
+		if (insn->src_reg == 0 && insn->imm == BPF_FUNC_timer_set_callback)
+			/* Mark this call insn as a prune point to trigger
+			 * is_state_visited() check before call itself is
+			 * processed by __check_func_call(). Otherwise new
+			 * async state will be pushed for further exploration.
+			 */
+			mark_prune_point(env, t);
+		/* For functions that invoke callbacks it is not known how many times
+		 * callback would be called. Verifier models callback calling functions
+		 * by repeatedly visiting callback bodies and returning to origin call
+		 * instruction.
+		 * In order to stop such iteration verifier needs to identify when a
+		 * state identical some state from a previous iteration is reached.
+		 * Check below forces creation of checkpoint before callback calling
+		 * instruction to allow search for such identical states.
+		 */
+		if (is_sync_callback_calling_insn(insn)) {
+			mark_calls_callback(env, t);
+			mark_force_checkpoint(env, t);
+			mark_prune_point(env, t);
+			mark_jmp_point(env, t);
+		}
+		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
+			struct bpf_kfunc_call_arg_meta meta;
+
+			ret = fetch_kfunc_meta(env, insn, &meta, NULL);
+			if (ret == 0 && is_iter_next_kfunc(&meta)) {
+				mark_prune_point(env, t);
+				/* Checking and saving state checkpoints at iter_next() call
+				 * is crucial for fast convergence of open-coded iterator loop
+				 * logic, so we need to force it. If we don't do that,
+				 * is_state_visited() might skip saving a checkpoint, causing
+				 * unnecessarily long sequence of not checkpointed
+				 * instructions and jumps, leading to exhaustion of jump
+				 * history buffer, and potentially other undesired outcomes.
+				 * It is expected that with correct open-coded iterators
+				 * convergence will happen quickly, so we don't run a risk of
+				 * exhausting memory.
+				 */
+				mark_force_checkpoint(env, t);
+			}
+		}
+		return visit_func_call_insn(t, insns, env, insn->src_reg == BPF_PSEUDO_CALL);
+
+	case BPF_JA:
+		if (BPF_SRC(insn->code) != BPF_K)
+			return -EINVAL;
+
+		if (BPF_CLASS(insn->code) == BPF_JMP)
+			off = insn->off;
+		else
+			off = insn->imm;
+
+		/* unconditional jump with single edge */
+		ret = push_insn(t, t + off + 1, FALLTHROUGH, env);
+		if (ret)
+			return ret;
+
+		mark_prune_point(env, t + off + 1);
+		mark_jmp_point(env, t + off + 1);
+
+		return ret;
+
+	default:
+		/* conditional jump with two edges */
+		mark_prune_point(env, t);
+
+		ret = push_insn(t, t + 1, FALLTHROUGH, env);
+		if (ret)
+			return ret;
+
+		return push_insn(t, t + insn->off + 1, BRANCH, env);
+	}
+}
+
+/* non-recursive depth-first-search to detect loops in BPF program
+ * loop == back-edge in directed graph
+ */
+static int check_cfg(struct bpf_verifier_env *env)
+{
+	int insn_cnt = env->prog->len;
+	int *insn_stack, *insn_state;
+	int ret = 0;
+	int i;
+
+	insn_state = env->cfg.insn_state = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+	if (!insn_state)
+		return -ENOMEM;
+
+	insn_stack = env->cfg.insn_stack = kvcalloc(insn_cnt, sizeof(int), GFP_KERNEL);
+	if (!insn_stack) {
+		kvfree(insn_state);
+		return -ENOMEM;
+	}
+
+	insn_state[0] = DISCOVERED; /* mark 1st insn as discovered */
+	insn_stack[0] = 0; /* 0 is the first instruction */
+	env->cfg.cur_stack = 1;
+
+	while (env->cfg.cur_stack > 0) {
+		int t = insn_stack[env->cfg.cur_stack - 1];
+
+		ret = visit_insn(t, env);
+		switch (ret) {
+		case DONE_EXPLORING:
+			insn_state[t] = EXPLORED;
+			env->cfg.cur_stack--;
+			break;
+		case KEEP_EXPLORING:
+			break;
+		default:
+			if (ret > 0) {
+				verbose(env, "visit_insn internal bug\n");
+				ret = -EFAULT;
+			}
+			goto err_free;
+		}
+	}
+
+	if (env->cfg.cur_stack < 0) {
+		verbose(env, "pop stack internal bug\n");
+		ret = -EFAULT;
+		goto err_free;
+	}
+
+	for (i = 0; i < insn_cnt; i++) {
+		struct bpf_insn *insn = &env->prog->insnsi[i];
+
+		if (insn_state[i] != EXPLORED) {
+			verbose(env, "unreachable insn %d\n", i);
+			ret = -EINVAL;
+			goto err_free;
+		}
+		if (bpf_is_ldimm64(insn)) {
+			if (insn_state[i + 1] != 0) {
+				verbose(env, "jump into the middle of ldimm64 insn %d\n", i);
+				ret = -EINVAL;
+				goto err_free;
+			}
+			i++; /* skip second half of ldimm64 */
+		}
+	}
+	ret = 0; /* cfg looks good */
+
+err_free:
+	kvfree(insn_state);
+	kvfree(insn_stack);
+	env->cfg.insn_state = env->cfg.insn_stack = NULL;
+	return ret;
+}
+
+static int check_abnormal_return(struct bpf_verifier_env *env)
+{
+	int i;
+
+	for (i = 1; i < env->subprog_cnt; i++) {
+		if (env->subprog_info[i].has_ld_abs) {
+			verbose(env, "LD_ABS is not allowed in subprogs without BTF\n");
+			return -EINVAL;
+		}
+		if (env->subprog_info[i].has_tail_call) {
+			verbose(env, "tail_call is not allowed in subprogs without BTF\n");
+			return -EINVAL;
+		}
+	}
+	return 0;
+}
+
+/* The minimum supported BTF func info size */
+#define MIN_BPF_FUNCINFO_SIZE	8
+#define MAX_FUNCINFO_REC_SIZE	252
+
+static int check_btf_func(struct bpf_verifier_env *env,
+			  const union bpf_attr *attr,
+			  bpfptr_t uattr)
+{
+	const struct btf_type *type, *func_proto, *ret_type;
+	u32 i, nfuncs, urec_size, min_size;
+	u32 krec_size = sizeof(struct bpf_func_info);
+	struct bpf_func_info *krecord;
+	struct bpf_func_info_aux *info_aux = NULL;
+	struct bpf_prog *prog;
+	const struct btf *btf;
+	bpfptr_t urecord;
+	u32 prev_offset = 0;
+	bool scalar_return;
+	int ret = -ENOMEM;
+
+	nfuncs = attr->func_info_cnt;
+	if (!nfuncs) {
+		if (check_abnormal_return(env))
+			return -EINVAL;
+		return 0;
+	}
+
+	if (nfuncs != env->subprog_cnt) {
+		verbose(env, "number of funcs in func_info doesn't match number of subprogs\n");
+		return -EINVAL;
+	}
+
+	urec_size = attr->func_info_rec_size;
+	if (urec_size < MIN_BPF_FUNCINFO_SIZE ||
+	    urec_size > MAX_FUNCINFO_REC_SIZE ||
+	    urec_size % sizeof(u32)) {
+		verbose(env, "invalid func info rec size %u\n", urec_size);
+		return -EINVAL;
+	}
+
+	prog = env->prog;
+	btf = prog->aux->btf;
+
+	urecord = make_bpfptr(attr->func_info, uattr.is_kernel);
+	min_size = min_t(u32, krec_size, urec_size);
+
+	krecord = kvcalloc(nfuncs, krec_size, GFP_KERNEL | __GFP_NOWARN);
+	if (!krecord)
+		return -ENOMEM;
+	info_aux = kcalloc(nfuncs, sizeof(*info_aux), GFP_KERNEL | __GFP_NOWARN);
+	if (!info_aux)
+		goto err_free;
+
+	for (i = 0; i < nfuncs; i++) {
+		ret = bpf_check_uarg_tail_zero(urecord, krec_size, urec_size);
+		if (ret) {
+			if (ret == -E2BIG) {
+				verbose(env, "nonzero tailing record in func info");
+				/* set the size kernel expects so loader can zero
+				 * out the rest of the record.
+				 */
+				if (copy_to_bpfptr_offset(uattr,
+							  offsetof(union bpf_attr, func_info_rec_size),
+							  &min_size, sizeof(min_size)))
+					ret = -EFAULT;
+			}
+			goto err_free;
+		}
+
+		if (copy_from_bpfptr(&krecord[i], urecord, min_size)) {
+			ret = -EFAULT;
+			goto err_free;
+		}
+
+		/* check insn_off */
+		ret = -EINVAL;
+		if (i == 0) {
+			if (krecord[i].insn_off) {
+				verbose(env,
+					"nonzero insn_off %u for the first func info record",
+					krecord[i].insn_off);
+				goto err_free;
+			}
+		} else if (krecord[i].insn_off <= prev_offset) {
+			verbose(env,
+				"same or smaller insn offset (%u) than previous func info record (%u)",
+				krecord[i].insn_off, prev_offset);
+			goto err_free;
+		}
+
+		if (env->subprog_info[i].start != krecord[i].insn_off) {
+			verbose(env, "func_info BTF section doesn't match subprog layout in BPF program\n");
+			goto err_free;
+		}
+
+		/* check type_id */
+		type = btf_type_by_id(btf, krecord[i].type_id);
+		if (!type || !btf_type_is_func(type)) {
+			verbose(env, "invalid type id %d in func info",
+				krecord[i].type_id);
+			goto err_free;
+		}
+		info_aux[i].linkage = BTF_INFO_VLEN(type->info);
+
+		func_proto = btf_type_by_id(btf, type->type);
+		if (unlikely(!func_proto || !btf_type_is_func_proto(func_proto)))
+			/* btf_func_check() already verified it during BTF load */
+			goto err_free;
+		ret_type = btf_type_skip_modifiers(btf, func_proto->type, NULL);
+		scalar_return =
+			btf_type_is_small_int(ret_type) || btf_is_any_enum(ret_type);
+		if (i && !scalar_return && env->subprog_info[i].has_ld_abs) {
+			verbose(env, "LD_ABS is only allowed in functions that return 'int'.\n");
+			goto err_free;
+		}
+		if (i && !scalar_return && env->subprog_info[i].has_tail_call) {
+			verbose(env, "tail_call is only allowed in functions that return 'int'.\n");
+			goto err_free;
+		}
+
+		prev_offset = krecord[i].insn_off;
+		bpfptr_add(&urecord, urec_size);
+	}
+
+	prog->aux->func_info = krecord;
+	prog->aux->func_info_cnt = nfuncs;
+	prog->aux->func_info_aux = info_aux;
+	return 0;
+
+err_free:
+	kvfree(krecord);
+	kfree(info_aux);
+	return ret;
+}
+
+static void adjust_btf_func(struct bpf_verifier_env *env)
+{
+	struct bpf_prog_aux *aux = env->prog->aux;
+	int i;
+
+	if (!aux->func_info)
+		return;
+
+	for (i = 0; i < env->subprog_cnt; i++)
+		aux->func_info[i].insn_off = env->subprog_info[i].start;
+}
+
+#define MIN_BPF_LINEINFO_SIZE	offsetofend(struct bpf_line_info, line_col)
+#define MAX_LINEINFO_REC_SIZE	MAX_FUNCINFO_REC_SIZE
+
+static int check_btf_line(struct bpf_verifier_env *env,
+			  const union bpf_attr *attr,
+			  bpfptr_t uattr)
+{
+	u32 i, s, nr_linfo, ncopy, expected_size, rec_size, prev_offset = 0;
+	struct bpf_subprog_info *sub;
+	struct bpf_line_info *linfo;
+	struct bpf_prog *prog;
+	const struct btf *btf;
+	bpfptr_t ulinfo;
+	int err;
+
+	nr_linfo = attr->line_info_cnt;
+	if (!nr_linfo)
+		return 0;
+	if (nr_linfo > INT_MAX / sizeof(struct bpf_line_info))
+		return -EINVAL;
+
+	rec_size = attr->line_info_rec_size;
+	if (rec_size < MIN_BPF_LINEINFO_SIZE ||
+	    rec_size > MAX_LINEINFO_REC_SIZE ||
+	    rec_size & (sizeof(u32) - 1))
+		return -EINVAL;
+
+	/* Need to zero it in case the userspace may
+	 * pass in a smaller bpf_line_info object.
+	 */
+	linfo = kvcalloc(nr_linfo, sizeof(struct bpf_line_info),
+			 GFP_KERNEL | __GFP_NOWARN);
+	if (!linfo)
+		return -ENOMEM;
+
+	prog = env->prog;
+	btf = prog->aux->btf;
+
+	s = 0;
+	sub = env->subprog_info;
+	ulinfo = make_bpfptr(attr->line_info, uattr.is_kernel);
+	expected_size = sizeof(struct bpf_line_info);
+	ncopy = min_t(u32, expected_size, rec_size);
+	for (i = 0; i < nr_linfo; i++) {
+		err = bpf_check_uarg_tail_zero(ulinfo, expected_size, rec_size);
+		if (err) {
+			if (err == -E2BIG) {
+				verbose(env, "nonzero tailing record in line_info");
+				if (copy_to_bpfptr_offset(uattr,
+							  offsetof(union bpf_attr, line_info_rec_size),
+							  &expected_size, sizeof(expected_size)))
+					err = -EFAULT;
+			}
+			goto err_free;
+		}
+
+		if (copy_from_bpfptr(&linfo[i], ulinfo, ncopy)) {
+			err = -EFAULT;
+			goto err_free;
+		}
+
+		/*
+		 * Check insn_off to ensure
+		 * 1) strictly increasing AND
+		 * 2) bounded by prog->len
+		 *
+		 * The linfo[0].insn_off == 0 check logically falls into
+		 * the later "missing bpf_line_info for func..." case
+		 * because the first linfo[0].insn_off must be the
+		 * first sub also and the first sub must have
+		 * subprog_info[0].start == 0.
+		 */
+		if ((i && linfo[i].insn_off <= prev_offset) ||
+		    linfo[i].insn_off >= prog->len) {
+			verbose(env, "Invalid line_info[%u].insn_off:%u (prev_offset:%u prog->len:%u)\n",
+				i, linfo[i].insn_off, prev_offset,
+				prog->len);
+			err = -EINVAL;
+			goto err_free;
+		}
+
+		if (!prog->insnsi[linfo[i].insn_off].code) {
+			verbose(env,
+				"Invalid insn code at line_info[%u].insn_off\n",
+				i);
+			err = -EINVAL;
+			goto err_free;
+		}
+
+		if (!btf_name_by_offset(btf, linfo[i].line_off) ||
+		    !btf_name_by_offset(btf, linfo[i].file_name_off)) {
+			verbose(env, "Invalid line_info[%u].line_off or .file_name_off\n", i);
+			err = -EINVAL;
+			goto err_free;
+		}
+
+		if (s != env->subprog_cnt) {
+			if (linfo[i].insn_off == sub[s].start) {
+				sub[s].linfo_idx = i;
+				s++;
+			} else if (sub[s].start < linfo[i].insn_off) {
+				verbose(env, "missing bpf_line_info for func#%u\n", s);
+				err = -EINVAL;
+				goto err_free;
+			}
+		}
+
+		prev_offset = linfo[i].insn_off;
+		bpfptr_add(&ulinfo, rec_size);
+	}
+
+	if (s != env->subprog_cnt) {
+		verbose(env, "missing bpf_line_info for %u funcs starting from func#%u\n",
+			env->subprog_cnt - s, s);
+		err = -EINVAL;
+		goto err_free;
+	}
+
+	prog->aux->linfo = linfo;
+	prog->aux->nr_linfo = nr_linfo;
+
+	return 0;
+
+err_free:
+	kvfree(linfo);
+	return err;
+}
+
+#define MIN_CORE_RELO_SIZE	sizeof(struct bpf_core_relo)
+#define MAX_CORE_RELO_SIZE	MAX_FUNCINFO_REC_SIZE
+
+static int check_core_relo(struct bpf_verifier_env *env,
+			   const union bpf_attr *attr,
+			   bpfptr_t uattr)
+{
+	u32 i, nr_core_relo, ncopy, expected_size, rec_size;
+	struct bpf_core_relo core_relo = {};
+	struct bpf_prog *prog = env->prog;
+	const struct btf *btf = prog->aux->btf;
+	struct bpf_core_ctx ctx = {
+		.log = &env->log,
+		.btf = btf,
+	};
+	bpfptr_t u_core_relo;
+	int err;
+
+	nr_core_relo = attr->core_relo_cnt;
+	if (!nr_core_relo)
+		return 0;
+	if (nr_core_relo > INT_MAX / sizeof(struct bpf_core_relo))
+		return -EINVAL;
+
+	rec_size = attr->core_relo_rec_size;
+	if (rec_size < MIN_CORE_RELO_SIZE ||
+	    rec_size > MAX_CORE_RELO_SIZE ||
+	    rec_size % sizeof(u32))
+		return -EINVAL;
+
+	u_core_relo = make_bpfptr(attr->core_relos, uattr.is_kernel);
+	expected_size = sizeof(struct bpf_core_relo);
+	ncopy = min_t(u32, expected_size, rec_size);
+
+	/* Unlike func_info and line_info, copy and apply each CO-RE
+	 * relocation record one at a time.
+	 */
+	for (i = 0; i < nr_core_relo; i++) {
+		/* future proofing when sizeof(bpf_core_relo) changes */
+		err = bpf_check_uarg_tail_zero(u_core_relo, expected_size, rec_size);
+		if (err) {
+			if (err == -E2BIG) {
+				verbose(env, "nonzero tailing record in core_relo");
+				if (copy_to_bpfptr_offset(uattr,
+							  offsetof(union bpf_attr, core_relo_rec_size),
+							  &expected_size, sizeof(expected_size)))
+					err = -EFAULT;
+			}
+			break;
+		}
+
+		if (copy_from_bpfptr(&core_relo, u_core_relo, ncopy)) {
+			err = -EFAULT;
+			break;
+		}
+
+		if (core_relo.insn_off % 8 || core_relo.insn_off / 8 >= prog->len) {
+			verbose(env, "Invalid core_relo[%u].insn_off:%u prog->len:%u\n",
+				i, core_relo.insn_off, prog->len);
+			err = -EINVAL;
+			break;
+		}
+
+		err = bpf_core_apply(&ctx, &core_relo, i,
+				     &prog->insnsi[core_relo.insn_off / 8]);
+		if (err)
+			break;
+		bpfptr_add(&u_core_relo, rec_size);
+	}
+	return err;
+}
+
+static int check_btf_info(struct bpf_verifier_env *env,
+			  const union bpf_attr *attr,
+			  bpfptr_t uattr)
+{
+	struct btf *btf;
+	int err;
+
+	if (!attr->func_info_cnt && !attr->line_info_cnt) {
+		if (check_abnormal_return(env))
+			return -EINVAL;
+		return 0;
+	}
+
+	btf = btf_get_by_fd(attr->prog_btf_fd);
+	if (IS_ERR(btf))
+		return PTR_ERR(btf);
+	if (btf_is_kernel(btf)) {
+		btf_put(btf);
+		return -EACCES;
+	}
+	env->prog->aux->btf = btf;
+
+	err = check_btf_func(env, attr, uattr);
+	if (err)
+		return err;
+
+	err = check_btf_line(env, attr, uattr);
+	if (err)
+		return err;
+
+	err = check_core_relo(env, attr, uattr);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+/* check %cur's range satisfies %old's */
+static bool range_within(struct bpf_reg_state *old,
+			 struct bpf_reg_state *cur)
+{
+	return old->umin_value <= cur->umin_value &&
+	       old->umax_value >= cur->umax_value &&
+	       old->smin_value <= cur->smin_value &&
+	       old->smax_value >= cur->smax_value &&
+	       old->u32_min_value <= cur->u32_min_value &&
+	       old->u32_max_value >= cur->u32_max_value &&
+	       old->s32_min_value <= cur->s32_min_value &&
+	       old->s32_max_value >= cur->s32_max_value;
+}
+
+/* If in the old state two registers had the same id, then they need to have
+ * the same id in the new state as well.  But that id could be different from
+ * the old state, so we need to track the mapping from old to new ids.
+ * Once we have seen that, say, a reg with old id 5 had new id 9, any subsequent
+ * regs with old id 5 must also have new id 9 for the new state to be safe.  But
+ * regs with a different old id could still have new id 9, we don't care about
+ * that.
+ * So we look through our idmap to see if this old id has been seen before.  If
+ * so, we require the new id to match; otherwise, we add the id pair to the map.
+ */
+static bool check_ids(u32 old_id, u32 cur_id, struct bpf_idmap *idmap)
+{
+	struct bpf_id_pair *map = idmap->map;
+	unsigned int i;
+
+	/* either both IDs should be set or both should be zero */
+	if (!!old_id != !!cur_id)
+		return false;
+
+	if (old_id == 0) /* cur_id == 0 as well */
+		return true;
+
+	for (i = 0; i < BPF_ID_MAP_SIZE; i++) {
+		if (!map[i].old) {
+			/* Reached an empty slot; haven't seen this id before */
+			map[i].old = old_id;
+			map[i].cur = cur_id;
+			return true;
+		}
+		if (map[i].old == old_id)
+			return map[i].cur == cur_id;
+		if (map[i].cur == cur_id)
+			return false;
+	}
+	/* We ran out of idmap slots, which should be impossible */
+	WARN_ON_ONCE(1);
+	return false;
+}
+
+/* Similar to check_ids(), but allocate a unique temporary ID
+ * for 'old_id' or 'cur_id' of zero.
+ * This makes pairs like '0 vs unique ID', 'unique ID vs 0' valid.
+ */
+static bool check_scalar_ids(u32 old_id, u32 cur_id, struct bpf_idmap *idmap)
+{
+	old_id = old_id ? old_id : ++idmap->tmp_id_gen;
+	cur_id = cur_id ? cur_id : ++idmap->tmp_id_gen;
+
+	return check_ids(old_id, cur_id, idmap);
+}
+
+static void clean_func_state(struct bpf_verifier_env *env,
+			     struct bpf_func_state *st)
+{
+	enum bpf_reg_liveness live;
+	int i, j;
+
+	for (i = 0; i < BPF_REG_FP; i++) {
+		live = st->regs[i].live;
+		/* liveness must not touch this register anymore */
+		st->regs[i].live |= REG_LIVE_DONE;
+		if (!(live & REG_LIVE_READ))
+			/* since the register is unused, clear its state
+			 * to make further comparison simpler
+			 */
+			__mark_reg_not_init(env, &st->regs[i]);
+	}
+
+	for (i = 0; i < st->allocated_stack / BPF_REG_SIZE; i++) {
+		live = st->stack[i].spilled_ptr.live;
+		/* liveness must not touch this stack slot anymore */
+		st->stack[i].spilled_ptr.live |= REG_LIVE_DONE;
+		if (!(live & REG_LIVE_READ)) {
+			__mark_reg_not_init(env, &st->stack[i].spilled_ptr);
+			for (j = 0; j < BPF_REG_SIZE; j++)
+				st->stack[i].slot_type[j] = STACK_INVALID;
+		}
+	}
+}
+
+static void clean_verifier_state(struct bpf_verifier_env *env,
+				 struct bpf_verifier_state *st)
+{
+	int i;
+
+	if (st->frame[0]->regs[0].live & REG_LIVE_DONE)
+		/* all regs in this state in all frames were already marked */
+		return;
+
+	for (i = 0; i <= st->curframe; i++)
+		clean_func_state(env, st->frame[i]);
+}
+
+/* the parentage chains form a tree.
+ * the verifier states are added to state lists at given insn and
+ * pushed into state stack for future exploration.
+ * when the verifier reaches bpf_exit insn some of the verifer states
+ * stored in the state lists have their final liveness state already,
+ * but a lot of states will get revised from liveness point of view when
+ * the verifier explores other branches.
+ * Example:
+ * 1: r0 = 1
+ * 2: if r1 == 100 goto pc+1
+ * 3: r0 = 2
+ * 4: exit
+ * when the verifier reaches exit insn the register r0 in the state list of
+ * insn 2 will be seen as !REG_LIVE_READ. Then the verifier pops the other_branch
+ * of insn 2 and goes exploring further. At the insn 4 it will walk the
+ * parentage chain from insn 4 into insn 2 and will mark r0 as REG_LIVE_READ.
+ *
+ * Since the verifier pushes the branch states as it sees them while exploring
+ * the program the condition of walking the branch instruction for the second
+ * time means that all states below this branch were already explored and
+ * their final liveness marks are already propagated.
+ * Hence when the verifier completes the search of state list in is_state_visited()
+ * we can call this clean_live_states() function to mark all liveness states
+ * as REG_LIVE_DONE to indicate that 'parent' pointers of 'struct bpf_reg_state'
+ * will not be used.
+ * This function also clears the registers and stack for states that !READ
+ * to simplify state merging.
+ *
+ * Important note here that walking the same branch instruction in the callee
+ * doesn't meant that the states are DONE. The verifier has to compare
+ * the callsites
+ */
+static void clean_live_states(struct bpf_verifier_env *env, int insn,
+			      struct bpf_verifier_state *cur)
+{
+	struct bpf_verifier_state_list *sl;
+
+	sl = *explored_state(env, insn);
+	while (sl) {
+		if (sl->state.branches)
+			goto next;
+		if (sl->state.insn_idx != insn ||
+		    !same_callsites(&sl->state, cur))
+			goto next;
+		clean_verifier_state(env, &sl->state);
+next:
+		sl = sl->next;
+	}
+}
+
+static bool regs_exact(const struct bpf_reg_state *rold,
+		       const struct bpf_reg_state *rcur,
+		       struct bpf_idmap *idmap)
+{
+	return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
+	       check_ids(rold->id, rcur->id, idmap) &&
+	       check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
+}
+
+/* Returns true if (rold safe implies rcur safe) */
+static bool regsafe(struct bpf_verifier_env *env, struct bpf_reg_state *rold,
+		    struct bpf_reg_state *rcur, struct bpf_idmap *idmap, bool exact)
+{
+	if (exact)
+		return regs_exact(rold, rcur, idmap);
+
+	if (!(rold->live & REG_LIVE_READ))
+		/* explored state didn't use this */
+		return true;
+	if (rold->type == NOT_INIT)
+		/* explored state can't have used this */
+		return true;
+	if (rcur->type == NOT_INIT)
+		return false;
+
+	/* Enforce that register types have to match exactly, including their
+	 * modifiers (like PTR_MAYBE_NULL, MEM_RDONLY, etc), as a general
+	 * rule.
+	 *
+	 * One can make a point that using a pointer register as unbounded
+	 * SCALAR would be technically acceptable, but this could lead to
+	 * pointer leaks because scalars are allowed to leak while pointers
+	 * are not. We could make this safe in special cases if root is
+	 * calling us, but it's probably not worth the hassle.
+	 *
+	 * Also, register types that are *not* MAYBE_NULL could technically be
+	 * safe to use as their MAYBE_NULL variants (e.g., PTR_TO_MAP_VALUE
+	 * is safe to be used as PTR_TO_MAP_VALUE_OR_NULL, provided both point
+	 * to the same map).
+	 * However, if the old MAYBE_NULL register then got NULL checked,
+	 * doing so could have affected others with the same id, and we can't
+	 * check for that because we lost the id when we converted to
+	 * a non-MAYBE_NULL variant.
+	 * So, as a general rule we don't allow mixing MAYBE_NULL and
+	 * non-MAYBE_NULL registers as well.
+	 */
+	if (rold->type != rcur->type)
+		return false;
+
+	switch (base_type(rold->type)) {
+	case SCALAR_VALUE:
+		if (env->explore_alu_limits) {
+			/* explore_alu_limits disables tnum_in() and range_within()
+			 * logic and requires everything to be strict
+			 */
+			return memcmp(rold, rcur, offsetof(struct bpf_reg_state, id)) == 0 &&
+			       check_scalar_ids(rold->id, rcur->id, idmap);
+		}
+		if (!rold->precise)
+			return true;
+		/* Why check_ids() for scalar registers?
+		 *
+		 * Consider the following BPF code:
+		 *   1: r6 = ... unbound scalar, ID=a ...
+		 *   2: r7 = ... unbound scalar, ID=b ...
+		 *   3: if (r6 > r7) goto +1
+		 *   4: r6 = r7
+		 *   5: if (r6 > X) goto ...
+		 *   6: ... memory operation using r7 ...
+		 *
+		 * First verification path is [1-6]:
+		 * - at (4) same bpf_reg_state::id (b) would be assigned to r6 and r7;
+		 * - at (5) r6 would be marked <= X, find_equal_scalars() would also mark
+		 *   r7 <= X, because r6 and r7 share same id.
+		 * Next verification path is [1-4, 6].
+		 *
+		 * Instruction (6) would be reached in two states:
+		 *   I.  r6{.id=b}, r7{.id=b} via path 1-6;
+		 *   II. r6{.id=a}, r7{.id=b} via path 1-4, 6.
+		 *
+		 * Use check_ids() to distinguish these states.
+		 * ---
+		 * Also verify that new value satisfies old value range knowledge.
+		 */
+		return range_within(rold, rcur) &&
+		       tnum_in(rold->var_off, rcur->var_off) &&
+		       check_scalar_ids(rold->id, rcur->id, idmap);
+	case PTR_TO_MAP_KEY:
+	case PTR_TO_MAP_VALUE:
+	case PTR_TO_MEM:
+	case PTR_TO_BUF:
+	case PTR_TO_TP_BUFFER:
+		/* If the new min/max/var_off satisfy the old ones and
+		 * everything else matches, we are OK.
+		 */
+		return memcmp(rold, rcur, offsetof(struct bpf_reg_state, var_off)) == 0 &&
+		       range_within(rold, rcur) &&
+		       tnum_in(rold->var_off, rcur->var_off) &&
+		       check_ids(rold->id, rcur->id, idmap) &&
+		       check_ids(rold->ref_obj_id, rcur->ref_obj_id, idmap);
+	case PTR_TO_PACKET_META:
+	case PTR_TO_PACKET:
+		/* We must have at least as much range as the old ptr
+		 * did, so that any accesses which were safe before are
+		 * still safe.  This is true even if old range < old off,
+		 * since someone could have accessed through (ptr - k), or
+		 * even done ptr -= k in a register, to get a safe access.
+		 */
+		if (rold->range > rcur->range)
+			return false;
+		/* If the offsets don't match, we can't trust our alignment;
+		 * nor can we be sure that we won't fall out of range.
+		 */
+		if (rold->off != rcur->off)
+			return false;
+		/* id relations must be preserved */
+		if (!check_ids(rold->id, rcur->id, idmap))
+			return false;
+		/* new val must satisfy old val knowledge */
+		return range_within(rold, rcur) &&
+		       tnum_in(rold->var_off, rcur->var_off);
+	case PTR_TO_STACK:
+		/* two stack pointers are equal only if they're pointing to
+		 * the same stack frame, since fp-8 in foo != fp-8 in bar
+		 */
+		return regs_exact(rold, rcur, idmap) && rold->frameno == rcur->frameno;
+	default:
+		return regs_exact(rold, rcur, idmap);
+	}
+}
+
+static bool stacksafe(struct bpf_verifier_env *env, struct bpf_func_state *old,
+		      struct bpf_func_state *cur, struct bpf_idmap *idmap, bool exact)
+{
+	int i, spi;
+
+	/* walk slots of the explored stack and ignore any additional
+	 * slots in the current stack, since explored(safe) state
+	 * didn't use them
+	 */
+	for (i = 0; i < old->allocated_stack; i++) {
+		struct bpf_reg_state *old_reg, *cur_reg;
+
+		spi = i / BPF_REG_SIZE;
+
+		if (exact &&
+		    old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
+		    cur->stack[spi].slot_type[i % BPF_REG_SIZE])
+			return false;
+
+		if (!(old->stack[spi].spilled_ptr.live & REG_LIVE_READ) && !exact) {
+			i += BPF_REG_SIZE - 1;
+			/* explored state didn't use this */
+			continue;
+		}
+
+		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_INVALID)
+			continue;
+
+		if (env->allow_uninit_stack &&
+		    old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC)
+			continue;
+
+		/* explored stack has more populated slots than current stack
+		 * and these slots were used
+		 */
+		if (i >= cur->allocated_stack)
+			return false;
+
+		/* if old state was safe with misc data in the stack
+		 * it will be safe with zero-initialized stack.
+		 * The opposite is not true
+		 */
+		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_MISC &&
+		    cur->stack[spi].slot_type[i % BPF_REG_SIZE] == STACK_ZERO)
+			continue;
+		if (old->stack[spi].slot_type[i % BPF_REG_SIZE] !=
+		    cur->stack[spi].slot_type[i % BPF_REG_SIZE])
+			/* Ex: old explored (safe) state has STACK_SPILL in
+			 * this stack slot, but current has STACK_MISC ->
+			 * this verifier states are not equivalent,
+			 * return false to continue verification of this path
+			 */
+			return false;
+		if (i % BPF_REG_SIZE != BPF_REG_SIZE - 1)
+			continue;
+		/* Both old and cur are having same slot_type */
+		switch (old->stack[spi].slot_type[BPF_REG_SIZE - 1]) {
+		case STACK_SPILL:
+			/* when explored and current stack slot are both storing
+			 * spilled registers, check that stored pointers types
+			 * are the same as well.
+			 * Ex: explored safe path could have stored
+			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -8}
+			 * but current path has stored:
+			 * (bpf_reg_state) {.type = PTR_TO_STACK, .off = -16}
+			 * such verifier states are not equivalent.
+			 * return false to continue verification of this path
+			 */
+			if (!regsafe(env, &old->stack[spi].spilled_ptr,
+				     &cur->stack[spi].spilled_ptr, idmap, exact))
+				return false;
+			break;
+		case STACK_DYNPTR:
+			old_reg = &old->stack[spi].spilled_ptr;
+			cur_reg = &cur->stack[spi].spilled_ptr;
+			if (old_reg->dynptr.type != cur_reg->dynptr.type ||
+			    old_reg->dynptr.first_slot != cur_reg->dynptr.first_slot ||
+			    !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
+				return false;
+			break;
+		case STACK_ITER:
+			old_reg = &old->stack[spi].spilled_ptr;
+			cur_reg = &cur->stack[spi].spilled_ptr;
+			/* iter.depth is not compared between states as it
+			 * doesn't matter for correctness and would otherwise
+			 * prevent convergence; we maintain it only to prevent
+			 * infinite loop check triggering, see
+			 * iter_active_depths_differ()
+			 */
+			if (old_reg->iter.btf != cur_reg->iter.btf ||
+			    old_reg->iter.btf_id != cur_reg->iter.btf_id ||
+			    old_reg->iter.state != cur_reg->iter.state ||
+			    /* ignore {old_reg,cur_reg}->iter.depth, see above */
+			    !check_ids(old_reg->ref_obj_id, cur_reg->ref_obj_id, idmap))
+				return false;
+			break;
+		case STACK_MISC:
+		case STACK_ZERO:
+		case STACK_INVALID:
+			continue;
+		/* Ensure that new unhandled slot types return false by default */
+		default:
+			return false;
+		}
+	}
+	return true;
+}
+
+static bool refsafe(struct bpf_func_state *old, struct bpf_func_state *cur,
+		    struct bpf_idmap *idmap)
+{
+	int i;
+
+	if (old->acquired_refs != cur->acquired_refs)
+		return false;
+
+	for (i = 0; i < old->acquired_refs; i++) {
+		if (!check_ids(old->refs[i].id, cur->refs[i].id, idmap))
+			return false;
+	}
+
+	return true;
+}
+
+/* compare two verifier states
+ *
+ * all states stored in state_list are known to be valid, since
+ * verifier reached 'bpf_exit' instruction through them
+ *
+ * this function is called when verifier exploring different branches of
+ * execution popped from the state stack. If it sees an old state that has
+ * more strict register state and more strict stack state then this execution
+ * branch doesn't need to be explored further, since verifier already
+ * concluded that more strict state leads to valid finish.
+ *
+ * Therefore two states are equivalent if register state is more conservative
+ * and explored stack state is more conservative than the current one.
+ * Example:
+ *       explored                   current
+ * (slot1=INV slot2=MISC) == (slot1=MISC slot2=MISC)
+ * (slot1=MISC slot2=MISC) != (slot1=INV slot2=MISC)
+ *
+ * In other words if current stack state (one being explored) has more
+ * valid slots than old one that already passed validation, it means
+ * the verifier can stop exploring and conclude that current state is valid too
+ *
+ * Similarly with registers. If explored state has register type as invalid
+ * whereas register type in current state is meaningful, it means that
+ * the current state will reach 'bpf_exit' instruction safely
+ */
+static bool func_states_equal(struct bpf_verifier_env *env, struct bpf_func_state *old,
+			      struct bpf_func_state *cur, bool exact)
+{
+	int i;
+
+	for (i = 0; i < MAX_BPF_REG; i++)
+		if (!regsafe(env, &old->regs[i], &cur->regs[i],
+			     &env->idmap_scratch, exact))
+			return false;
+
+	if (!stacksafe(env, old, cur, &env->idmap_scratch, exact))
+		return false;
+
+	if (!refsafe(old, cur, &env->idmap_scratch))
+		return false;
+
+	return true;
+}
+
+static void reset_idmap_scratch(struct bpf_verifier_env *env)
+{
+	env->idmap_scratch.tmp_id_gen = env->id_gen;
+	memset(&env->idmap_scratch.map, 0, sizeof(env->idmap_scratch.map));
+}
+
+static bool states_equal(struct bpf_verifier_env *env,
+			 struct bpf_verifier_state *old,
+			 struct bpf_verifier_state *cur,
+			 bool exact)
+{
+	int i;
+
+	if (old->curframe != cur->curframe)
+		return false;
+
+	reset_idmap_scratch(env);
+
+	/* Verification state from speculative execution simulation
+	 * must never prune a non-speculative execution one.
+	 */
+	if (old->speculative && !cur->speculative)
+		return false;
+
+	if (old->active_lock.ptr != cur->active_lock.ptr)
+		return false;
+
+	/* Old and cur active_lock's have to be either both present
+	 * or both absent.
+	 */
+	if (!!old->active_lock.id != !!cur->active_lock.id)
+		return false;
+
+	if (old->active_lock.id &&
+	    !check_ids(old->active_lock.id, cur->active_lock.id, &env->idmap_scratch))
+		return false;
+
+	if (old->active_rcu_lock != cur->active_rcu_lock)
+		return false;
+
+	/* for states to be equal callsites have to be the same
+	 * and all frame states need to be equivalent
+	 */
+	for (i = 0; i <= old->curframe; i++) {
+		if (old->frame[i]->callsite != cur->frame[i]->callsite)
+			return false;
+		if (!func_states_equal(env, old->frame[i], cur->frame[i], exact))
+			return false;
+	}
+	return true;
+}
+
+/* Return 0 if no propagation happened. Return negative error code if error
+ * happened. Otherwise, return the propagated bit.
+ */
+static int propagate_liveness_reg(struct bpf_verifier_env *env,
+				  struct bpf_reg_state *reg,
+				  struct bpf_reg_state *parent_reg)
+{
+	u8 parent_flag = parent_reg->live & REG_LIVE_READ;
+	u8 flag = reg->live & REG_LIVE_READ;
+	int err;
+
+	/* When comes here, read flags of PARENT_REG or REG could be any of
+	 * REG_LIVE_READ64, REG_LIVE_READ32, REG_LIVE_NONE. There is no need
+	 * of propagation if PARENT_REG has strongest REG_LIVE_READ64.
+	 */
+	if (parent_flag == REG_LIVE_READ64 ||
+	    /* Or if there is no read flag from REG. */
+	    !flag ||
+	    /* Or if the read flag from REG is the same as PARENT_REG. */
+	    parent_flag == flag)
+		return 0;
+
+	err = mark_reg_read(env, reg, parent_reg, flag);
+	if (err)
+		return err;
+
+	return flag;
+}
+
+/* A write screens off any subsequent reads; but write marks come from the
+ * straight-line code between a state and its parent.  When we arrive at an
+ * equivalent state (jump target or such) we didn't arrive by the straight-line
+ * code, so read marks in the state must propagate to the parent regardless
+ * of the state's write marks. That's what 'parent == state->parent' comparison
+ * in mark_reg_read() is for.
+ */
+static int propagate_liveness(struct bpf_verifier_env *env,
+			      const struct bpf_verifier_state *vstate,
+			      struct bpf_verifier_state *vparent)
+{
+	struct bpf_reg_state *state_reg, *parent_reg;
+	struct bpf_func_state *state, *parent;
+	int i, frame, err = 0;
+
+	if (vparent->curframe != vstate->curframe) {
+		WARN(1, "propagate_live: parent frame %d current frame %d\n",
+		     vparent->curframe, vstate->curframe);
+		return -EFAULT;
+	}
+	/* Propagate read liveness of registers... */
+	BUILD_BUG_ON(BPF_REG_FP + 1 != MAX_BPF_REG);
+	for (frame = 0; frame <= vstate->curframe; frame++) {
+		parent = vparent->frame[frame];
+		state = vstate->frame[frame];
+		parent_reg = parent->regs;
+		state_reg = state->regs;
+		/* We don't need to worry about FP liveness, it's read-only */
+		for (i = frame < vstate->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++) {
+			err = propagate_liveness_reg(env, &state_reg[i],
+						     &parent_reg[i]);
+			if (err < 0)
+				return err;
+			if (err == REG_LIVE_READ64)
+				mark_insn_zext(env, &parent_reg[i]);
+		}
+
+		/* Propagate stack slots. */
+		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE &&
+			    i < parent->allocated_stack / BPF_REG_SIZE; i++) {
+			parent_reg = &parent->stack[i].spilled_ptr;
+			state_reg = &state->stack[i].spilled_ptr;
+			err = propagate_liveness_reg(env, state_reg,
+						     parent_reg);
+			if (err < 0)
+				return err;
+		}
+	}
+	return 0;
+}
+
+/* find precise scalars in the previous equivalent state and
+ * propagate them into the current state
+ */
+static int propagate_precision(struct bpf_verifier_env *env,
+			       const struct bpf_verifier_state *old)
+{
+	struct bpf_reg_state *state_reg;
+	struct bpf_func_state *state;
+	int i, err = 0, fr;
+	bool first;
+
+	for (fr = old->curframe; fr >= 0; fr--) {
+		state = old->frame[fr];
+		state_reg = state->regs;
+		first = true;
+		for (i = 0; i < BPF_REG_FP; i++, state_reg++) {
+			if (state_reg->type != SCALAR_VALUE ||
+			    !state_reg->precise ||
+			    !(state_reg->live & REG_LIVE_READ))
+				continue;
+			if (env->log.level & BPF_LOG_LEVEL2) {
+				if (first)
+					verbose(env, "frame %d: propagating r%d", fr, i);
+				else
+					verbose(env, ",r%d", i);
+			}
+			bt_set_frame_reg(&env->bt, fr, i);
+			first = false;
+		}
+
+		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+			if (!is_spilled_reg(&state->stack[i]))
+				continue;
+			state_reg = &state->stack[i].spilled_ptr;
+			if (state_reg->type != SCALAR_VALUE ||
+			    !state_reg->precise ||
+			    !(state_reg->live & REG_LIVE_READ))
+				continue;
+			if (env->log.level & BPF_LOG_LEVEL2) {
+				if (first)
+					verbose(env, "frame %d: propagating fp%d",
+						fr, (-i - 1) * BPF_REG_SIZE);
+				else
+					verbose(env, ",fp%d", (-i - 1) * BPF_REG_SIZE);
+			}
+			bt_set_frame_slot(&env->bt, fr, i);
+			first = false;
+		}
+		if (!first)
+			verbose(env, "\n");
+	}
+
+	err = mark_chain_precision_batch(env);
+	if (err < 0)
+		return err;
+
+	return 0;
+}
+
+static bool states_maybe_looping(struct bpf_verifier_state *old,
+				 struct bpf_verifier_state *cur)
+{
+	struct bpf_func_state *fold, *fcur;
+	int i, fr = cur->curframe;
+
+	if (old->curframe != fr)
+		return false;
+
+	fold = old->frame[fr];
+	fcur = cur->frame[fr];
+	for (i = 0; i < MAX_BPF_REG; i++)
+		if (memcmp(&fold->regs[i], &fcur->regs[i],
+			   offsetof(struct bpf_reg_state, parent)))
+			return false;
+	return true;
+}
+
+static bool is_iter_next_insn(struct bpf_verifier_env *env, int insn_idx)
+{
+	return env->insn_aux_data[insn_idx].is_iter_next;
+}
+
+/* is_state_visited() handles iter_next() (see process_iter_next_call() for
+ * terminology) calls specially: as opposed to bounded BPF loops, it *expects*
+ * states to match, which otherwise would look like an infinite loop. So while
+ * iter_next() calls are taken care of, we still need to be careful and
+ * prevent erroneous and too eager declaration of "ininite loop", when
+ * iterators are involved.
+ *
+ * Here's a situation in pseudo-BPF assembly form:
+ *
+ *   0: again:                          ; set up iter_next() call args
+ *   1:   r1 = &it                      ; <CHECKPOINT HERE>
+ *   2:   call bpf_iter_num_next        ; this is iter_next() call
+ *   3:   if r0 == 0 goto done
+ *   4:   ... something useful here ...
+ *   5:   goto again                    ; another iteration
+ *   6: done:
+ *   7:   r1 = &it
+ *   8:   call bpf_iter_num_destroy     ; clean up iter state
+ *   9:   exit
+ *
+ * This is a typical loop. Let's assume that we have a prune point at 1:,
+ * before we get to `call bpf_iter_num_next` (e.g., because of that `goto
+ * again`, assuming other heuristics don't get in a way).
+ *
+ * When we first time come to 1:, let's say we have some state X. We proceed
+ * to 2:, fork states, enqueue ACTIVE, validate NULL case successfully, exit.
+ * Now we come back to validate that forked ACTIVE state. We proceed through
+ * 3-5, come to goto, jump to 1:. Let's assume our state didn't change, so we
+ * are converging. But the problem is that we don't know that yet, as this
+ * convergence has to happen at iter_next() call site only. So if nothing is
+ * done, at 1: verifier will use bounded loop logic and declare infinite
+ * looping (and would be *technically* correct, if not for iterator's
+ * "eventual sticky NULL" contract, see process_iter_next_call()). But we
+ * don't want that. So what we do in process_iter_next_call() when we go on
+ * another ACTIVE iteration, we bump slot->iter.depth, to mark that it's
+ * a different iteration. So when we suspect an infinite loop, we additionally
+ * check if any of the *ACTIVE* iterator states depths differ. If yes, we
+ * pretend we are not looping and wait for next iter_next() call.
+ *
+ * This only applies to ACTIVE state. In DRAINED state we don't expect to
+ * loop, because that would actually mean infinite loop, as DRAINED state is
+ * "sticky", and so we'll keep returning into the same instruction with the
+ * same state (at least in one of possible code paths).
+ *
+ * This approach allows to keep infinite loop heuristic even in the face of
+ * active iterator. E.g., C snippet below is and will be detected as
+ * inifintely looping:
+ *
+ *   struct bpf_iter_num it;
+ *   int *p, x;
+ *
+ *   bpf_iter_num_new(&it, 0, 10);
+ *   while ((p = bpf_iter_num_next(&t))) {
+ *       x = p;
+ *       while (x--) {} // <<-- infinite loop here
+ *   }
+ *
+ */
+static bool iter_active_depths_differ(struct bpf_verifier_state *old, struct bpf_verifier_state *cur)
+{
+	struct bpf_reg_state *slot, *cur_slot;
+	struct bpf_func_state *state;
+	int i, fr;
+
+	for (fr = old->curframe; fr >= 0; fr--) {
+		state = old->frame[fr];
+		for (i = 0; i < state->allocated_stack / BPF_REG_SIZE; i++) {
+			if (state->stack[i].slot_type[0] != STACK_ITER)
+				continue;
+
+			slot = &state->stack[i].spilled_ptr;
+			if (slot->iter.state != BPF_ITER_STATE_ACTIVE)
+				continue;
+
+			cur_slot = &cur->frame[fr]->stack[i].spilled_ptr;
+			if (cur_slot->iter.depth != slot->iter.depth)
+				return true;
+		}
+	}
+	return false;
+}
+
+static int is_state_visited(struct bpf_verifier_env *env, int insn_idx)
+{
+	struct bpf_verifier_state_list *new_sl;
+	struct bpf_verifier_state_list *sl, **pprev;
+	struct bpf_verifier_state *cur = env->cur_state, *new, *loop_entry;
+	int i, j, n, err, states_cnt = 0;
+	bool force_new_state = env->test_state_freq || is_force_checkpoint(env, insn_idx);
+	bool add_new_state = force_new_state;
+	bool force_exact;
+
+	/* bpf progs typically have pruning point every 4 instructions
+	 * http://vger.kernel.org/bpfconf2019.html#session-1
+	 * Do not add new state for future pruning if the verifier hasn't seen
+	 * at least 2 jumps and at least 8 instructions.
+	 * This heuristics helps decrease 'total_states' and 'peak_states' metric.
+	 * In tests that amounts to up to 50% reduction into total verifier
+	 * memory consumption and 20% verifier time speedup.
+	 */
+	if (env->jmps_processed - env->prev_jmps_processed >= 2 &&
+	    env->insn_processed - env->prev_insn_processed >= 8)
+		add_new_state = true;
+
+	pprev = explored_state(env, insn_idx);
+	sl = *pprev;
+
+	clean_live_states(env, insn_idx, cur);
+
+	while (sl) {
+		states_cnt++;
+		if (sl->state.insn_idx != insn_idx)
+			goto next;
+
+		if (sl->state.branches) {
+			struct bpf_func_state *frame = sl->state.frame[sl->state.curframe];
+
+			if (frame->in_async_callback_fn &&
+			    frame->async_entry_cnt != cur->frame[cur->curframe]->async_entry_cnt) {
+				/* Different async_entry_cnt means that the verifier is
+				 * processing another entry into async callback.
+				 * Seeing the same state is not an indication of infinite
+				 * loop or infinite recursion.
+				 * But finding the same state doesn't mean that it's safe
+				 * to stop processing the current state. The previous state
+				 * hasn't yet reached bpf_exit, since state.branches > 0.
+				 * Checking in_async_callback_fn alone is not enough either.
+				 * Since the verifier still needs to catch infinite loops
+				 * inside async callbacks.
+				 */
+				goto skip_inf_loop_check;
+			}
+			/* BPF open-coded iterators loop detection is special.
+			 * states_maybe_looping() logic is too simplistic in detecting
+			 * states that *might* be equivalent, because it doesn't know
+			 * about ID remapping, so don't even perform it.
+			 * See process_iter_next_call() and iter_active_depths_differ()
+			 * for overview of the logic. When current and one of parent
+			 * states are detected as equivalent, it's a good thing: we prove
+			 * convergence and can stop simulating further iterations.
+			 * It's safe to assume that iterator loop will finish, taking into
+			 * account iter_next() contract of eventually returning
+			 * sticky NULL result.
+			 *
+			 * Note, that states have to be compared exactly in this case because
+			 * read and precision marks might not be finalized inside the loop.
+			 * E.g. as in the program below:
+			 *
+			 *     1. r7 = -16
+			 *     2. r6 = bpf_get_prandom_u32()
+			 *     3. while (bpf_iter_num_next(&fp[-8])) {
+			 *     4.   if (r6 != 42) {
+			 *     5.     r7 = -32
+			 *     6.     r6 = bpf_get_prandom_u32()
+			 *     7.     continue
+			 *     8.   }
+			 *     9.   r0 = r10
+			 *    10.   r0 += r7
+			 *    11.   r8 = *(u64 *)(r0 + 0)
+			 *    12.   r6 = bpf_get_prandom_u32()
+			 *    13. }
+			 *
+			 * Here verifier would first visit path 1-3, create a checkpoint at 3
+			 * with r7=-16, continue to 4-7,3. Existing checkpoint at 3 does
+			 * not have read or precision mark for r7 yet, thus inexact states
+			 * comparison would discard current state with r7=-32
+			 * => unsafe memory access at 11 would not be caught.
+			 */
+			if (is_iter_next_insn(env, insn_idx)) {
+				if (states_equal(env, &sl->state, cur, true)) {
+					struct bpf_func_state *cur_frame;
+					struct bpf_reg_state *iter_state, *iter_reg;
+					int spi;
+
+					cur_frame = cur->frame[cur->curframe];
+					/* btf_check_iter_kfuncs() enforces that
+					 * iter state pointer is always the first arg
+					 */
+					iter_reg = &cur_frame->regs[BPF_REG_1];
+					/* current state is valid due to states_equal(),
+					 * so we can assume valid iter and reg state,
+					 * no need for extra (re-)validations
+					 */
+					spi = __get_spi(iter_reg->off + iter_reg->var_off.value);
+					iter_state = &func(env, iter_reg)->stack[spi].spilled_ptr;
+					if (iter_state->iter.state == BPF_ITER_STATE_ACTIVE) {
+						update_loop_entry(cur, &sl->state);
+						goto hit;
+					}
+				}
+				goto skip_inf_loop_check;
+			}
+			if (calls_callback(env, insn_idx)) {
+				if (states_equal(env, &sl->state, cur, true))
+					goto hit;
+				goto skip_inf_loop_check;
+			}
+			/* attempt to detect infinite loop to avoid unnecessary doomed work */
+			if (states_maybe_looping(&sl->state, cur) &&
+			    states_equal(env, &sl->state, cur, false) &&
+			    !iter_active_depths_differ(&sl->state, cur) &&
+			    sl->state.callback_unroll_depth == cur->callback_unroll_depth) {
+				verbose_linfo(env, insn_idx, "; ");
+				verbose(env, "infinite loop detected at insn %d\n", insn_idx);
+				verbose(env, "cur state:");
+				print_verifier_state(env, cur->frame[cur->curframe], true);
+				verbose(env, "old state:");
+				print_verifier_state(env, sl->state.frame[cur->curframe], true);
+				return -EINVAL;
+			}
+			/* if the verifier is processing a loop, avoid adding new state
+			 * too often, since different loop iterations have distinct
+			 * states and may not help future pruning.
+			 * This threshold shouldn't be too low to make sure that
+			 * a loop with large bound will be rejected quickly.
+			 * The most abusive loop will be:
+			 * r1 += 1
+			 * if r1 < 1000000 goto pc-2
+			 * 1M insn_procssed limit / 100 == 10k peak states.
+			 * This threshold shouldn't be too high either, since states
+			 * at the end of the loop are likely to be useful in pruning.
+			 */
+skip_inf_loop_check:
+			if (!force_new_state &&
+			    env->jmps_processed - env->prev_jmps_processed < 20 &&
+			    env->insn_processed - env->prev_insn_processed < 100)
+				add_new_state = false;
+			goto miss;
+		}
+		/* If sl->state is a part of a loop and this loop's entry is a part of
+		 * current verification path then states have to be compared exactly.
+		 * 'force_exact' is needed to catch the following case:
+		 *
+		 *                initial     Here state 'succ' was processed first,
+		 *                  |         it was eventually tracked to produce a
+		 *                  V         state identical to 'hdr'.
+		 *     .---------> hdr        All branches from 'succ' had been explored
+		 *     |            |         and thus 'succ' has its .branches == 0.
+		 *     |            V
+		 *     |    .------...        Suppose states 'cur' and 'succ' correspond
+		 *     |    |       |         to the same instruction + callsites.
+		 *     |    V       V         In such case it is necessary to check
+		 *     |   ...     ...        if 'succ' and 'cur' are states_equal().
+		 *     |    |       |         If 'succ' and 'cur' are a part of the
+		 *     |    V       V         same loop exact flag has to be set.
+		 *     |   succ <- cur        To check if that is the case, verify
+		 *     |    |                 if loop entry of 'succ' is in current
+		 *     |    V                 DFS path.
+		 *     |   ...
+		 *     |    |
+		 *     '----'
+		 *
+		 * Additional details are in the comment before get_loop_entry().
+		 */
+		loop_entry = get_loop_entry(&sl->state);
+		force_exact = loop_entry && loop_entry->branches > 0;
+		if (states_equal(env, &sl->state, cur, force_exact)) {
+			if (force_exact)
+				update_loop_entry(cur, loop_entry);
+hit:
+			sl->hit_cnt++;
+			/* reached equivalent register/stack state,
+			 * prune the search.
+			 * Registers read by the continuation are read by us.
+			 * If we have any write marks in env->cur_state, they
+			 * will prevent corresponding reads in the continuation
+			 * from reaching our parent (an explored_state).  Our
+			 * own state will get the read marks recorded, but
+			 * they'll be immediately forgotten as we're pruning
+			 * this state and will pop a new one.
+			 */
+			err = propagate_liveness(env, &sl->state, cur);
+
+			/* if previous state reached the exit with precision and
+			 * current state is equivalent to it (except precsion marks)
+			 * the precision needs to be propagated back in
+			 * the current state.
+			 */
+			err = err ? : push_jmp_history(env, cur);
+			err = err ? : propagate_precision(env, &sl->state);
+			if (err)
+				return err;
+			return 1;
+		}
+miss:
+		/* when new state is not going to be added do not increase miss count.
+		 * Otherwise several loop iterations will remove the state
+		 * recorded earlier. The goal of these heuristics is to have
+		 * states from some iterations of the loop (some in the beginning
+		 * and some at the end) to help pruning.
+		 */
+		if (add_new_state)
+			sl->miss_cnt++;
+		/* heuristic to determine whether this state is beneficial
+		 * to keep checking from state equivalence point of view.
+		 * Higher numbers increase max_states_per_insn and verification time,
+		 * but do not meaningfully decrease insn_processed.
+		 * 'n' controls how many times state could miss before eviction.
+		 * Use bigger 'n' for checkpoints because evicting checkpoint states
+		 * too early would hinder iterator convergence.
+		 */
+		n = is_force_checkpoint(env, insn_idx) && sl->state.branches > 0 ? 64 : 3;
+		if (sl->miss_cnt > sl->hit_cnt * n + n) {
+			/* the state is unlikely to be useful. Remove it to
+			 * speed up verification
+			 */
+			*pprev = sl->next;
+			if (sl->state.frame[0]->regs[0].live & REG_LIVE_DONE &&
+			    !sl->state.used_as_loop_entry) {
+				u32 br = sl->state.branches;
+
+				WARN_ONCE(br,
+					  "BUG live_done but branches_to_explore %d\n",
+					  br);
+				free_verifier_state(&sl->state, false);
+				kfree(sl);
+				env->peak_states--;
+			} else {
+				/* cannot free this state, since parentage chain may
+				 * walk it later. Add it for free_list instead to
+				 * be freed at the end of verification
+				 */
+				sl->next = env->free_list;
+				env->free_list = sl;
+			}
+			sl = *pprev;
+			continue;
+		}
+next:
+		pprev = &sl->next;
+		sl = *pprev;
+	}
+
+	if (env->max_states_per_insn < states_cnt)
+		env->max_states_per_insn = states_cnt;
+
+	if (!env->bpf_capable && states_cnt > BPF_COMPLEXITY_LIMIT_STATES)
+		return 0;
+
+	if (!add_new_state)
+		return 0;
+
+	/* There were no equivalent states, remember the current one.
+	 * Technically the current state is not proven to be safe yet,
+	 * but it will either reach outer most bpf_exit (which means it's safe)
+	 * or it will be rejected. When there are no loops the verifier won't be
+	 * seeing this tuple (frame[0].callsite, frame[1].callsite, .. insn_idx)
+	 * again on the way to bpf_exit.
+	 * When looping the sl->state.branches will be > 0 and this state
+	 * will not be considered for equivalence until branches == 0.
+	 */
+	new_sl = kzalloc(sizeof(struct bpf_verifier_state_list), GFP_KERNEL);
+	if (!new_sl)
+		return -ENOMEM;
+	env->total_states++;
+	env->peak_states++;
+	env->prev_jmps_processed = env->jmps_processed;
+	env->prev_insn_processed = env->insn_processed;
+
+	/* forget precise markings we inherited, see __mark_chain_precision */
+	if (env->bpf_capable)
+		mark_all_scalars_imprecise(env, cur);
+
+	/* add new state to the head of linked list */
+	new = &new_sl->state;
+	err = copy_verifier_state(new, cur);
+	if (err) {
+		free_verifier_state(new, false);
+		kfree(new_sl);
+		return err;
+	}
+	new->insn_idx = insn_idx;
+	WARN_ONCE(new->branches != 1,
+		  "BUG is_state_visited:branches_to_explore=%d insn %d\n", new->branches, insn_idx);
+
+	cur->parent = new;
+	cur->first_insn_idx = insn_idx;
+	cur->dfs_depth = new->dfs_depth + 1;
+	clear_jmp_history(cur);
+	new_sl->next = *explored_state(env, insn_idx);
+	*explored_state(env, insn_idx) = new_sl;
+	/* connect new state to parentage chain. Current frame needs all
+	 * registers connected. Only r6 - r9 of the callers are alive (pushed
+	 * to the stack implicitly by JITs) so in callers' frames connect just
+	 * r6 - r9 as an optimization. Callers will have r1 - r5 connected to
+	 * the state of the call instruction (with WRITTEN set), and r0 comes
+	 * from callee with its full parentage chain, anyway.
+	 */
+	/* clear write marks in current state: the writes we did are not writes
+	 * our child did, so they don't screen off its reads from us.
+	 * (There are no read marks in current state, because reads always mark
+	 * their parent and current state never has children yet.  Only
+	 * explored_states can get read marks.)
+	 */
+	for (j = 0; j <= cur->curframe; j++) {
+		for (i = j < cur->curframe ? BPF_REG_6 : 0; i < BPF_REG_FP; i++)
+			cur->frame[j]->regs[i].parent = &new->frame[j]->regs[i];
+		for (i = 0; i < BPF_REG_FP; i++)
+			cur->frame[j]->regs[i].live = REG_LIVE_NONE;
+	}
+
+	/* all stack frames are accessible from callee, clear them all */
+	for (j = 0; j <= cur->curframe; j++) {
+		struct bpf_func_state *frame = cur->frame[j];
+		struct bpf_func_state *newframe = new->frame[j];
+
+		for (i = 0; i < frame->allocated_stack / BPF_REG_SIZE; i++) {
+			frame->stack[i].spilled_ptr.live = REG_LIVE_NONE;
+			frame->stack[i].spilled_ptr.parent =
+						&newframe->stack[i].spilled_ptr;
+		}
+	}
+	return 0;
+}
+
+/* Return true if it's OK to have the same insn return a different type. */
+static bool reg_type_mismatch_ok(enum bpf_reg_type type)
+{
+	switch (base_type(type)) {
+	case PTR_TO_CTX:
+	case PTR_TO_SOCKET:
+	case PTR_TO_SOCK_COMMON:
+	case PTR_TO_TCP_SOCK:
+	case PTR_TO_XDP_SOCK:
+	case PTR_TO_BTF_ID:
+		return false;
+	default:
+		return true;
+	}
+}
+
+/* If an instruction was previously used with particular pointer types, then we
+ * need to be careful to avoid cases such as the below, where it may be ok
+ * for one branch accessing the pointer, but not ok for the other branch:
+ *
+ * R1 = sock_ptr
+ * goto X;
+ * ...
+ * R1 = some_other_valid_ptr;
+ * goto X;
+ * ...
+ * R2 = *(u32 *)(R1 + 0);
+ */
+static bool reg_type_mismatch(enum bpf_reg_type src, enum bpf_reg_type prev)
+{
+	return src != prev && (!reg_type_mismatch_ok(src) ||
+			       !reg_type_mismatch_ok(prev));
+}
+
+static int save_aux_ptr_type(struct bpf_verifier_env *env, enum bpf_reg_type type,
+			     bool allow_trust_missmatch)
+{
+	enum bpf_reg_type *prev_type = &env->insn_aux_data[env->insn_idx].ptr_type;
+
+	if (*prev_type == NOT_INIT) {
+		/* Saw a valid insn
+		 * dst_reg = *(u32 *)(src_reg + off)
+		 * save type to validate intersecting paths
+		 */
+		*prev_type = type;
+	} else if (reg_type_mismatch(type, *prev_type)) {
+		/* Abuser program is trying to use the same insn
+		 * dst_reg = *(u32*) (src_reg + off)
+		 * with different pointer types:
+		 * src_reg == ctx in one branch and
+		 * src_reg == stack|map in some other branch.
+		 * Reject it.
+		 */
+		if (allow_trust_missmatch &&
+		    base_type(type) == PTR_TO_BTF_ID &&
+		    base_type(*prev_type) == PTR_TO_BTF_ID) {
+			/*
+			 * Have to support a use case when one path through
+			 * the program yields TRUSTED pointer while another
+			 * is UNTRUSTED. Fallback to UNTRUSTED to generate
+			 * BPF_PROBE_MEM/BPF_PROBE_MEMSX.
+			 */
+			*prev_type = PTR_TO_BTF_ID | PTR_UNTRUSTED;
+		} else {
+			verbose(env, "same insn cannot be used with different pointers\n");
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static int do_check(struct bpf_verifier_env *env)
+{
+	bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
+	struct bpf_verifier_state *state = env->cur_state;
+	struct bpf_insn *insns = env->prog->insnsi;
+	struct bpf_reg_state *regs;
+	int insn_cnt = env->prog->len;
+	bool do_print_state = false;
+	int prev_insn_idx = -1;
+
+	for (;;) {
+		struct bpf_insn *insn;
+		u8 class;
+		int err;
+
+		env->prev_insn_idx = prev_insn_idx;
+		if (env->insn_idx >= insn_cnt) {
+			verbose(env, "invalid insn idx %d insn_cnt %d\n",
+				env->insn_idx, insn_cnt);
+			return -EFAULT;
+		}
+
+		insn = &insns[env->insn_idx];
+		class = BPF_CLASS(insn->code);
+
+		if (++env->insn_processed > BPF_COMPLEXITY_LIMIT_INSNS) {
+			verbose(env,
+				"BPF program is too large. Processed %d insn\n",
+				env->insn_processed);
+			return -E2BIG;
+		}
+
+		state->last_insn_idx = env->prev_insn_idx;
+
+		if (is_prune_point(env, env->insn_idx)) {
+			err = is_state_visited(env, env->insn_idx);
+			if (err < 0)
+				return err;
+			if (err == 1) {
+				/* found equivalent state, can prune the search */
+				if (env->log.level & BPF_LOG_LEVEL) {
+					if (do_print_state)
+						verbose(env, "\nfrom %d to %d%s: safe\n",
+							env->prev_insn_idx, env->insn_idx,
+							env->cur_state->speculative ?
+							" (speculative execution)" : "");
+					else
+						verbose(env, "%d: safe\n", env->insn_idx);
+				}
+				goto process_bpf_exit;
+			}
+		}
+
+		if (is_jmp_point(env, env->insn_idx)) {
+			err = push_jmp_history(env, state);
+			if (err)
+				return err;
+		}
+
+		if (signal_pending(current))
+			return -EAGAIN;
+
+		if (need_resched())
+			cond_resched();
+
+		if (env->log.level & BPF_LOG_LEVEL2 && do_print_state) {
+			verbose(env, "\nfrom %d to %d%s:",
+				env->prev_insn_idx, env->insn_idx,
+				env->cur_state->speculative ?
+				" (speculative execution)" : "");
+			print_verifier_state(env, state->frame[state->curframe], true);
+			do_print_state = false;
+		}
+
+		if (env->log.level & BPF_LOG_LEVEL) {
+			const struct bpf_insn_cbs cbs = {
+				.cb_call	= disasm_kfunc_name,
+				.cb_print	= verbose,
+				.private_data	= env,
+			};
+
+			if (verifier_state_scratched(env))
+				print_insn_state(env, state->frame[state->curframe]);
+
+			verbose_linfo(env, env->insn_idx, "; ");
+			env->prev_log_pos = env->log.end_pos;
+			verbose(env, "%d: ", env->insn_idx);
+			print_bpf_insn(&cbs, insn, env->allow_ptr_leaks);
+			env->prev_insn_print_pos = env->log.end_pos - env->prev_log_pos;
+			env->prev_log_pos = env->log.end_pos;
+		}
+
+		if (bpf_prog_is_offloaded(env->prog->aux)) {
+			err = bpf_prog_offload_verify_insn(env, env->insn_idx,
+							   env->prev_insn_idx);
+			if (err)
+				return err;
+		}
+
+		regs = cur_regs(env);
+		sanitize_mark_insn_seen(env);
+		prev_insn_idx = env->insn_idx;
+
+		if (class == BPF_ALU || class == BPF_ALU64) {
+			err = check_alu_op(env, insn);
+			if (err)
+				return err;
+
+		} else if (class == BPF_LDX) {
+			enum bpf_reg_type src_reg_type;
+
+			/* check for reserved fields is already done */
+
+			/* check src operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+
+			err = check_reg_arg(env, insn->dst_reg, DST_OP_NO_MARK);
+			if (err)
+				return err;
+
+			src_reg_type = regs[insn->src_reg].type;
+
+			/* check that memory (src_reg + off) is readable,
+			 * the state of dst_reg will be updated by this func
+			 */
+			err = check_mem_access(env, env->insn_idx, insn->src_reg,
+					       insn->off, BPF_SIZE(insn->code),
+					       BPF_READ, insn->dst_reg, false,
+					       BPF_MODE(insn->code) == BPF_MEMSX);
+			if (err)
+				return err;
+
+			err = save_aux_ptr_type(env, src_reg_type, true);
+			if (err)
+				return err;
+		} else if (class == BPF_STX) {
+			enum bpf_reg_type dst_reg_type;
+
+			if (BPF_MODE(insn->code) == BPF_ATOMIC) {
+				err = check_atomic(env, env->insn_idx, insn);
+				if (err)
+					return err;
+				env->insn_idx++;
+				continue;
+			}
+
+			if (BPF_MODE(insn->code) != BPF_MEM || insn->imm != 0) {
+				verbose(env, "BPF_STX uses reserved fields\n");
+				return -EINVAL;
+			}
+
+			/* check src1 operand */
+			err = check_reg_arg(env, insn->src_reg, SRC_OP);
+			if (err)
+				return err;
+			/* check src2 operand */
+			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+			if (err)
+				return err;
+
+			dst_reg_type = regs[insn->dst_reg].type;
+
+			/* check that memory (dst_reg + off) is writeable */
+			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+					       insn->off, BPF_SIZE(insn->code),
+					       BPF_WRITE, insn->src_reg, false, false);
+			if (err)
+				return err;
+
+			err = save_aux_ptr_type(env, dst_reg_type, false);
+			if (err)
+				return err;
+		} else if (class == BPF_ST) {
+			enum bpf_reg_type dst_reg_type;
+
+			if (BPF_MODE(insn->code) != BPF_MEM ||
+			    insn->src_reg != BPF_REG_0) {
+				verbose(env, "BPF_ST uses reserved fields\n");
+				return -EINVAL;
+			}
+			/* check src operand */
+			err = check_reg_arg(env, insn->dst_reg, SRC_OP);
+			if (err)
+				return err;
+
+			dst_reg_type = regs[insn->dst_reg].type;
+
+			/* check that memory (dst_reg + off) is writeable */
+			err = check_mem_access(env, env->insn_idx, insn->dst_reg,
+					       insn->off, BPF_SIZE(insn->code),
+					       BPF_WRITE, -1, false, false);
+			if (err)
+				return err;
+
+			err = save_aux_ptr_type(env, dst_reg_type, false);
+			if (err)
+				return err;
+		} else if (class == BPF_JMP || class == BPF_JMP32) {
+			u8 opcode = BPF_OP(insn->code);
+
+			env->jmps_processed++;
+			if (opcode == BPF_CALL) {
+				if (BPF_SRC(insn->code) != BPF_K ||
+				    (insn->src_reg != BPF_PSEUDO_KFUNC_CALL
+				     && insn->off != 0) ||
+				    (insn->src_reg != BPF_REG_0 &&
+				     insn->src_reg != BPF_PSEUDO_CALL &&
+				     insn->src_reg != BPF_PSEUDO_KFUNC_CALL) ||
+				    insn->dst_reg != BPF_REG_0 ||
+				    class == BPF_JMP32) {
+					verbose(env, "BPF_CALL uses reserved fields\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_graph_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);
+				else if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
+					err = check_kfunc_call(env, insn, &env->insn_idx);
+				else
+					err = check_helper_call(env, insn, &env->insn_idx);
+				if (err)
+					return err;
+
+				mark_reg_scratched(env, BPF_REG_0);
+			} else if (opcode == BPF_JA) {
+				if (BPF_SRC(insn->code) != BPF_K ||
+				    insn->src_reg != BPF_REG_0 ||
+				    insn->dst_reg != BPF_REG_0 ||
+				    (class == BPF_JMP && insn->imm != 0) ||
+				    (class == BPF_JMP32 && insn->off != 0)) {
+					verbose(env, "BPF_JA uses reserved fields\n");
+					return -EINVAL;
+				}
+
+				if (class == BPF_JMP)
+					env->insn_idx += insn->off + 1;
+				else
+					env->insn_idx += insn->imm + 1;
+				continue;
+
+			} else if (opcode == BPF_EXIT) {
+				if (BPF_SRC(insn->code) != BPF_K ||
+				    insn->imm != 0 ||
+				    insn->src_reg != BPF_REG_0 ||
+				    insn->dst_reg != BPF_REG_0 ||
+				    class == BPF_JMP32) {
+					verbose(env, "BPF_EXIT uses reserved fields\n");
+					return -EINVAL;
+				}
+
+				if (env->cur_state->active_lock.ptr &&
+				    !in_rbtree_lock_required_cb(env)) {
+					verbose(env, "bpf_spin_unlock is missing\n");
+					return -EINVAL;
+				}
+
+				if (env->cur_state->active_rcu_lock &&
+				    !in_rbtree_lock_required_cb(env)) {
+					verbose(env, "bpf_rcu_read_unlock is missing\n");
+					return -EINVAL;
+				}
+
+				/* We must do check_reference_leak here before
+				 * prepare_func_exit to handle the case when
+				 * state->curframe > 0, it may be a callback
+				 * function, for which reference_state must
+				 * match caller reference state when it exits.
+				 */
+				err = check_reference_leak(env);
+				if (err)
+					return err;
+
+				if (state->curframe) {
+					/* exit from nested function */
+					err = prepare_func_exit(env, &env->insn_idx);
+					if (err)
+						return err;
+					do_print_state = true;
+					continue;
+				}
+
+				err = check_return_code(env);
+				if (err)
+					return err;
+process_bpf_exit:
+				mark_verifier_state_scratched(env);
+				update_branch_counts(env, env->cur_state);
+				err = pop_stack(env, &prev_insn_idx,
+						&env->insn_idx, pop_log);
+				if (err < 0) {
+					if (err != -ENOENT)
+						return err;
+					break;
+				} else {
+					do_print_state = true;
+					continue;
+				}
+			} else {
+				err = check_cond_jmp_op(env, insn, &env->insn_idx);
+				if (err)
+					return err;
+			}
+		} else if (class == BPF_LD) {
+			u8 mode = BPF_MODE(insn->code);
+
+			if (mode == BPF_ABS || mode == BPF_IND) {
+				err = check_ld_abs(env, insn);
+				if (err)
+					return err;
+
+			} else if (mode == BPF_IMM) {
+				err = check_ld_imm(env, insn);
+				if (err)
+					return err;
+
+				env->insn_idx++;
+				sanitize_mark_insn_seen(env);
+			} else {
+				verbose(env, "invalid BPF_LD mode\n");
+				return -EINVAL;
+			}
+		} else {
+			verbose(env, "unknown insn class %d\n", class);
+			return -EINVAL;
+		}
+
+		env->insn_idx++;
+	}
+
+	return 0;
+}
+
+static int find_btf_percpu_datasec(struct btf *btf)
+{
+	const struct btf_type *t;
+	const char *tname;
+	int i, n;
+
+	/*
+	 * Both vmlinux and module each have their own ".data..percpu"
+	 * DATASECs in BTF. So for module's case, we need to skip vmlinux BTF
+	 * types to look at only module's own BTF types.
+	 */
+	n = btf_nr_types(btf);
+	if (btf_is_module(btf))
+		i = btf_nr_types(btf_vmlinux);
+	else
+		i = 1;
+
+	for(; i < n; i++) {
+		t = btf_type_by_id(btf, i);
+		if (BTF_INFO_KIND(t->info) != BTF_KIND_DATASEC)
+			continue;
+
+		tname = btf_name_by_offset(btf, t->name_off);
+		if (!strcmp(tname, ".data..percpu"))
+			return i;
+	}
+
+	return -ENOENT;
+}
+
+/* replace pseudo btf_id with kernel symbol address */
+static int check_pseudo_btf_id(struct bpf_verifier_env *env,
+			       struct bpf_insn *insn,
+			       struct bpf_insn_aux_data *aux)
+{
+	const struct btf_var_secinfo *vsi;
+	const struct btf_type *datasec;
+	struct btf_mod_pair *btf_mod;
+	const struct btf_type *t;
+	const char *sym_name;
+	bool percpu = false;
+	u32 type, id = insn->imm;
+	struct btf *btf;
+	s32 datasec_id;
+	u64 addr;
+	int i, btf_fd, err;
+
+	btf_fd = insn[1].imm;
+	if (btf_fd) {
+		btf = btf_get_by_fd(btf_fd);
+		if (IS_ERR(btf)) {
+			verbose(env, "invalid module BTF object FD specified.\n");
+			return -EINVAL;
+		}
+	} else {
+		if (!btf_vmlinux) {
+			verbose(env, "kernel is missing BTF, make sure CONFIG_DEBUG_INFO_BTF=y is specified in Kconfig.\n");
+			return -EINVAL;
+		}
+		btf = btf_vmlinux;
+		btf_get(btf);
+	}
+
+	t = btf_type_by_id(btf, id);
+	if (!t) {
+		verbose(env, "ldimm64 insn specifies invalid btf_id %d.\n", id);
+		err = -ENOENT;
+		goto err_put;
+	}
+
+	if (!btf_type_is_var(t) && !btf_type_is_func(t)) {
+		verbose(env, "pseudo btf_id %d in ldimm64 isn't KIND_VAR or KIND_FUNC\n", id);
+		err = -EINVAL;
+		goto err_put;
+	}
+
+	sym_name = btf_name_by_offset(btf, t->name_off);
+	addr = kallsyms_lookup_name(sym_name);
+	if (!addr) {
+		verbose(env, "ldimm64 failed to find the address for kernel symbol '%s'.\n",
+			sym_name);
+		err = -ENOENT;
+		goto err_put;
+	}
+	insn[0].imm = (u32)addr;
+	insn[1].imm = addr >> 32;
+
+	if (btf_type_is_func(t)) {
+		aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
+		aux->btf_var.mem_size = 0;
+		goto check_btf;
+	}
+
+	datasec_id = find_btf_percpu_datasec(btf);
+	if (datasec_id > 0) {
+		datasec = btf_type_by_id(btf, datasec_id);
+		for_each_vsi(i, datasec, vsi) {
+			if (vsi->type == id) {
+				percpu = true;
+				break;
+			}
+		}
+	}
+
+	type = t->type;
+	t = btf_type_skip_modifiers(btf, type, NULL);
+	if (percpu) {
+		aux->btf_var.reg_type = PTR_TO_BTF_ID | MEM_PERCPU;
+		aux->btf_var.btf = btf;
+		aux->btf_var.btf_id = type;
+	} else if (!btf_type_is_struct(t)) {
+		const struct btf_type *ret;
+		const char *tname;
+		u32 tsize;
+
+		/* resolve the type size of ksym. */
+		ret = btf_resolve_size(btf, t, &tsize);
+		if (IS_ERR(ret)) {
+			tname = btf_name_by_offset(btf, t->name_off);
+			verbose(env, "ldimm64 unable to resolve the size of type '%s': %ld\n",
+				tname, PTR_ERR(ret));
+			err = -EINVAL;
+			goto err_put;
+		}
+		aux->btf_var.reg_type = PTR_TO_MEM | MEM_RDONLY;
+		aux->btf_var.mem_size = tsize;
+	} else {
+		aux->btf_var.reg_type = PTR_TO_BTF_ID;
+		aux->btf_var.btf = btf;
+		aux->btf_var.btf_id = type;
+	}
+check_btf:
+	/* check whether we recorded this BTF (and maybe module) already */
+	for (i = 0; i < env->used_btf_cnt; i++) {
+		if (env->used_btfs[i].btf == btf) {
+			btf_put(btf);
+			return 0;
+		}
+	}
+
+	if (env->used_btf_cnt >= MAX_USED_BTFS) {
+		err = -E2BIG;
+		goto err_put;
+	}
+
+	btf_mod = &env->used_btfs[env->used_btf_cnt];
+	btf_mod->btf = btf;
+	btf_mod->module = NULL;
+
+	/* if we reference variables from kernel module, bump its refcount */
+	if (btf_is_module(btf)) {
+		btf_mod->module = btf_try_get_module(btf);
+		if (!btf_mod->module) {
+			err = -ENXIO;
+			goto err_put;
+		}
+	}
+
+	env->used_btf_cnt++;
+
+	return 0;
+err_put:
+	btf_put(btf);
+	return err;
+}
+
+static bool is_tracing_prog_type(enum bpf_prog_type type)
+{
+	switch (type) {
+	case BPF_PROG_TYPE_KPROBE:
+	case BPF_PROG_TYPE_TRACEPOINT:
+	case BPF_PROG_TYPE_PERF_EVENT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT:
+	case BPF_PROG_TYPE_RAW_TRACEPOINT_WRITABLE:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static int check_map_prog_compatibility(struct bpf_verifier_env *env,
+					struct bpf_map *map,
+					struct bpf_prog *prog)
+
+{
+	enum bpf_prog_type prog_type = resolve_prog_type(prog);
+
+	if (btf_record_has_field(map->record, BPF_LIST_HEAD) ||
+	    btf_record_has_field(map->record, BPF_RB_ROOT)) {
+		if (is_tracing_prog_type(prog_type)) {
+			verbose(env, "tracing progs cannot use bpf_{list_head,rb_root} yet\n");
+			return -EINVAL;
+		}
+	}
+
+	if (btf_record_has_field(map->record, BPF_SPIN_LOCK)) {
+		if (prog_type == BPF_PROG_TYPE_SOCKET_FILTER) {
+			verbose(env, "socket filter progs cannot use bpf_spin_lock yet\n");
+			return -EINVAL;
+		}
+
+		if (is_tracing_prog_type(prog_type)) {
+			verbose(env, "tracing progs cannot use bpf_spin_lock yet\n");
+			return -EINVAL;
+		}
+	}
+
+	if (btf_record_has_field(map->record, BPF_TIMER)) {
+		if (is_tracing_prog_type(prog_type)) {
+			verbose(env, "tracing progs cannot use bpf_timer yet\n");
+			return -EINVAL;
+		}
+	}
+
+	if ((bpf_prog_is_offloaded(prog->aux) || bpf_map_is_offloaded(map)) &&
+	    !bpf_offload_prog_map_match(prog, map)) {
+		verbose(env, "offload device mismatch between prog and map\n");
+		return -EINVAL;
+	}
+
+	if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
+		verbose(env, "bpf_struct_ops map cannot be used in prog\n");
+		return -EINVAL;
+	}
+
+	if (prog->aux->sleepable)
+		switch (map->map_type) {
+		case BPF_MAP_TYPE_HASH:
+		case BPF_MAP_TYPE_LRU_HASH:
+		case BPF_MAP_TYPE_ARRAY:
+		case BPF_MAP_TYPE_PERCPU_HASH:
+		case BPF_MAP_TYPE_PERCPU_ARRAY:
+		case BPF_MAP_TYPE_LRU_PERCPU_HASH:
+		case BPF_MAP_TYPE_ARRAY_OF_MAPS:
+		case BPF_MAP_TYPE_HASH_OF_MAPS:
+		case BPF_MAP_TYPE_RINGBUF:
+		case BPF_MAP_TYPE_USER_RINGBUF:
+		case BPF_MAP_TYPE_INODE_STORAGE:
+		case BPF_MAP_TYPE_SK_STORAGE:
+		case BPF_MAP_TYPE_TASK_STORAGE:
+		case BPF_MAP_TYPE_CGRP_STORAGE:
+			break;
+		default:
+			verbose(env,
+				"Sleepable programs can only use array, hash, ringbuf and local storage maps\n");
+			return -EINVAL;
+		}
+
+	return 0;
+}
+
+static bool bpf_map_is_cgroup_storage(struct bpf_map *map)
+{
+	return (map->map_type == BPF_MAP_TYPE_CGROUP_STORAGE ||
+		map->map_type == BPF_MAP_TYPE_PERCPU_CGROUP_STORAGE);
+}
+
+/* find and rewrite pseudo imm in ld_imm64 instructions:
+ *
+ * 1. if it accesses map FD, replace it with actual map pointer.
+ * 2. if it accesses btf_id of a VAR, replace it with pointer to the var.
+ *
+ * NOTE: btf_vmlinux is required for converting pseudo btf_id.
+ */
+static int resolve_pseudo_ldimm64(struct bpf_verifier_env *env)
+{
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	int i, j, err;
+
+	err = bpf_prog_calc_tag(env->prog);
+	if (err)
+		return err;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (BPF_CLASS(insn->code) == BPF_LDX &&
+		    ((BPF_MODE(insn->code) != BPF_MEM && BPF_MODE(insn->code) != BPF_MEMSX) ||
+		    insn->imm != 0)) {
+			verbose(env, "BPF_LDX uses reserved fields\n");
+			return -EINVAL;
+		}
+
+		if (insn[0].code == (BPF_LD | BPF_IMM | BPF_DW)) {
+			struct bpf_insn_aux_data *aux;
+			struct bpf_map *map;
+			struct fd f;
+			u64 addr;
+			u32 fd;
+
+			if (i == insn_cnt - 1 || insn[1].code != 0 ||
+			    insn[1].dst_reg != 0 || insn[1].src_reg != 0 ||
+			    insn[1].off != 0) {
+				verbose(env, "invalid bpf_ld_imm64 insn\n");
+				return -EINVAL;
+			}
+
+			if (insn[0].src_reg == 0)
+				/* valid generic load 64-bit imm */
+				goto next_insn;
+
+			if (insn[0].src_reg == BPF_PSEUDO_BTF_ID) {
+				aux = &env->insn_aux_data[i];
+				err = check_pseudo_btf_id(env, insn, aux);
+				if (err)
+					return err;
+				goto next_insn;
+			}
+
+			if (insn[0].src_reg == BPF_PSEUDO_FUNC) {
+				aux = &env->insn_aux_data[i];
+				aux->ptr_type = PTR_TO_FUNC;
+				goto next_insn;
+			}
+
+			/* In final convert_pseudo_ld_imm64() step, this is
+			 * converted into regular 64-bit imm load insn.
+			 */
+			switch (insn[0].src_reg) {
+			case BPF_PSEUDO_MAP_VALUE:
+			case BPF_PSEUDO_MAP_IDX_VALUE:
+				break;
+			case BPF_PSEUDO_MAP_FD:
+			case BPF_PSEUDO_MAP_IDX:
+				if (insn[1].imm == 0)
+					break;
+				fallthrough;
+			default:
+				verbose(env, "unrecognized bpf_ld_imm64 insn\n");
+				return -EINVAL;
+			}
+
+			switch (insn[0].src_reg) {
+			case BPF_PSEUDO_MAP_IDX_VALUE:
+			case BPF_PSEUDO_MAP_IDX:
+				if (bpfptr_is_null(env->fd_array)) {
+					verbose(env, "fd_idx without fd_array is invalid\n");
+					return -EPROTO;
+				}
+				if (copy_from_bpfptr_offset(&fd, env->fd_array,
+							    insn[0].imm * sizeof(fd),
+							    sizeof(fd)))
+					return -EFAULT;
+				break;
+			default:
+				fd = insn[0].imm;
+				break;
+			}
+
+			f = fdget(fd);
+			map = __bpf_map_get(f);
+			if (IS_ERR(map)) {
+				verbose(env, "fd %d is not pointing to valid bpf_map\n",
+					insn[0].imm);
+				return PTR_ERR(map);
+			}
+
+			err = check_map_prog_compatibility(env, map, env->prog);
+			if (err) {
+				fdput(f);
+				return err;
+			}
+
+			aux = &env->insn_aux_data[i];
+			if (insn[0].src_reg == BPF_PSEUDO_MAP_FD ||
+			    insn[0].src_reg == BPF_PSEUDO_MAP_IDX) {
+				addr = (unsigned long)map;
+			} else {
+				u32 off = insn[1].imm;
+
+				if (off >= BPF_MAX_VAR_OFF) {
+					verbose(env, "direct value offset of %u is not allowed\n", off);
+					fdput(f);
+					return -EINVAL;
+				}
+
+				if (!map->ops->map_direct_value_addr) {
+					verbose(env, "no direct value access support for this map type\n");
+					fdput(f);
+					return -EINVAL;
+				}
+
+				err = map->ops->map_direct_value_addr(map, &addr, off);
+				if (err) {
+					verbose(env, "invalid access to map value pointer, value_size=%u off=%u\n",
+						map->value_size, off);
+					fdput(f);
+					return err;
+				}
+
+				aux->map_off = off;
+				addr += off;
+			}
+
+			insn[0].imm = (u32)addr;
+			insn[1].imm = addr >> 32;
+
+			/* check whether we recorded this map already */
+			for (j = 0; j < env->used_map_cnt; j++) {
+				if (env->used_maps[j] == map) {
+					aux->map_index = j;
+					fdput(f);
+					goto next_insn;
+				}
+			}
+
+			if (env->used_map_cnt >= MAX_USED_MAPS) {
+				fdput(f);
+				return -E2BIG;
+			}
+
+			/* hold the map. If the program is rejected by verifier,
+			 * the map will be released by release_maps() or it
+			 * will be used by the valid program until it's unloaded
+			 * and all maps are released in free_used_maps()
+			 */
+			bpf_map_inc(map);
+
+			aux->map_index = env->used_map_cnt;
+			env->used_maps[env->used_map_cnt++] = map;
+
+			if (bpf_map_is_cgroup_storage(map) &&
+			    bpf_cgroup_storage_assign(env->prog->aux, map)) {
+				verbose(env, "only one cgroup storage of each type is allowed\n");
+				fdput(f);
+				return -EBUSY;
+			}
+
+			fdput(f);
+next_insn:
+			insn++;
+			i++;
+			continue;
+		}
+
+		/* Basic sanity check before we invest more work here. */
+		if (!bpf_opcode_in_insntable(insn->code)) {
+			verbose(env, "unknown opcode %02x\n", insn->code);
+			return -EINVAL;
+		}
+	}
+
+	/* now all pseudo BPF_LD_IMM64 instructions load valid
+	 * 'struct bpf_map *' into a register instead of user map_fd.
+	 * These pointers will be used later by verifier to validate map access.
+	 */
+	return 0;
+}
+
+/* drop refcnt of maps used by the rejected program */
+static void release_maps(struct bpf_verifier_env *env)
+{
+	__bpf_free_used_maps(env->prog->aux, env->used_maps,
+			     env->used_map_cnt);
+}
+
+/* drop refcnt of maps used by the rejected program */
+static void release_btfs(struct bpf_verifier_env *env)
+{
+	__bpf_free_used_btfs(env->prog->aux, env->used_btfs,
+			     env->used_btf_cnt);
+}
+
+/* convert pseudo BPF_LD_IMM64 into generic BPF_LD_IMM64 */
+static void convert_pseudo_ld_imm64(struct bpf_verifier_env *env)
+{
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	int i;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (insn->code != (BPF_LD | BPF_IMM | BPF_DW))
+			continue;
+		if (insn->src_reg == BPF_PSEUDO_FUNC)
+			continue;
+		insn->src_reg = 0;
+	}
+}
+
+/* single env->prog->insni[off] instruction was replaced with the range
+ * insni[off, off + cnt).  Adjust corresponding insn_aux_data by copying
+ * [0, off) and [off, end) to new locations, so the patched range stays zero
+ */
+static void adjust_insn_aux_data(struct bpf_verifier_env *env,
+				 struct bpf_insn_aux_data *new_data,
+				 struct bpf_prog *new_prog, u32 off, u32 cnt)
+{
+	struct bpf_insn_aux_data *old_data = env->insn_aux_data;
+	struct bpf_insn *insn = new_prog->insnsi;
+	u32 old_seen = old_data[off].seen;
+	u32 prog_len;
+	int i;
+
+	/* aux info at OFF always needs adjustment, no matter fast path
+	 * (cnt == 1) is taken or not. There is no guarantee INSN at OFF is the
+	 * original insn at old prog.
+	 */
+	old_data[off].zext_dst = insn_has_def32(env, insn + off + cnt - 1);
+
+	if (cnt == 1)
+		return;
+	prog_len = new_prog->len;
+
+	memcpy(new_data, old_data, sizeof(struct bpf_insn_aux_data) * off);
+	memcpy(new_data + off + cnt - 1, old_data + off,
+	       sizeof(struct bpf_insn_aux_data) * (prog_len - off - cnt + 1));
+	for (i = off; i < off + cnt - 1; i++) {
+		/* Expand insni[off]'s seen count to the patched range. */
+		new_data[i].seen = old_seen;
+		new_data[i].zext_dst = insn_has_def32(env, insn + i);
+	}
+	env->insn_aux_data = new_data;
+	vfree(old_data);
+}
+
+static void adjust_subprog_starts(struct bpf_verifier_env *env, u32 off, u32 len)
+{
+	int i;
+
+	if (len == 1)
+		return;
+	/* NOTE: fake 'exit' subprog should be updated as well. */
+	for (i = 0; i <= env->subprog_cnt; i++) {
+		if (env->subprog_info[i].start <= off)
+			continue;
+		env->subprog_info[i].start += len - 1;
+	}
+}
+
+static void adjust_poke_descs(struct bpf_prog *prog, u32 off, u32 len)
+{
+	struct bpf_jit_poke_descriptor *tab = prog->aux->poke_tab;
+	int i, sz = prog->aux->size_poke_tab;
+	struct bpf_jit_poke_descriptor *desc;
+
+	for (i = 0; i < sz; i++) {
+		desc = &tab[i];
+		if (desc->insn_idx <= off)
+			continue;
+		desc->insn_idx += len - 1;
+	}
+}
+
+static struct bpf_prog *bpf_patch_insn_data(struct bpf_verifier_env *env, u32 off,
+					    const struct bpf_insn *patch, u32 len)
+{
+	struct bpf_prog *new_prog;
+	struct bpf_insn_aux_data *new_data = NULL;
+
+	if (len > 1) {
+		new_data = vzalloc(array_size(env->prog->len + len - 1,
+					      sizeof(struct bpf_insn_aux_data)));
+		if (!new_data)
+			return NULL;
+	}
+
+	new_prog = bpf_patch_insn_single(env->prog, off, patch, len);
+	if (IS_ERR(new_prog)) {
+		if (PTR_ERR(new_prog) == -ERANGE)
+			verbose(env,
+				"insn %d cannot be patched due to 16-bit range\n",
+				env->insn_aux_data[off].orig_idx);
+		vfree(new_data);
+		return NULL;
+	}
+	adjust_insn_aux_data(env, new_data, new_prog, off, len);
+	adjust_subprog_starts(env, off, len);
+	adjust_poke_descs(new_prog, off, len);
+	return new_prog;
+}
+
+static int adjust_subprog_starts_after_remove(struct bpf_verifier_env *env,
+					      u32 off, u32 cnt)
+{
+	int i, j;
+
+	/* find first prog starting at or after off (first to remove) */
+	for (i = 0; i < env->subprog_cnt; i++)
+		if (env->subprog_info[i].start >= off)
+			break;
+	/* find first prog starting at or after off + cnt (first to stay) */
+	for (j = i; j < env->subprog_cnt; j++)
+		if (env->subprog_info[j].start >= off + cnt)
+			break;
+	/* if j doesn't start exactly at off + cnt, we are just removing
+	 * the front of previous prog
+	 */
+	if (env->subprog_info[j].start != off + cnt)
+		j--;
+
+	if (j > i) {
+		struct bpf_prog_aux *aux = env->prog->aux;
+		int move;
+
+		/* move fake 'exit' subprog as well */
+		move = env->subprog_cnt + 1 - j;
+
+		memmove(env->subprog_info + i,
+			env->subprog_info + j,
+			sizeof(*env->subprog_info) * move);
+		env->subprog_cnt -= j - i;
+
+		/* remove func_info */
+		if (aux->func_info) {
+			move = aux->func_info_cnt - j;
+
+			memmove(aux->func_info + i,
+				aux->func_info + j,
+				sizeof(*aux->func_info) * move);
+			aux->func_info_cnt -= j - i;
+			/* func_info->insn_off is set after all code rewrites,
+			 * in adjust_btf_func() - no need to adjust
+			 */
+		}
+	} else {
+		/* convert i from "first prog to remove" to "first to adjust" */
+		if (env->subprog_info[i].start == off)
+			i++;
+	}
+
+	/* update fake 'exit' subprog as well */
+	for (; i <= env->subprog_cnt; i++)
+		env->subprog_info[i].start -= cnt;
+
+	return 0;
+}
+
+static int bpf_adj_linfo_after_remove(struct bpf_verifier_env *env, u32 off,
+				      u32 cnt)
+{
+	struct bpf_prog *prog = env->prog;
+	u32 i, l_off, l_cnt, nr_linfo;
+	struct bpf_line_info *linfo;
+
+	nr_linfo = prog->aux->nr_linfo;
+	if (!nr_linfo)
+		return 0;
+
+	linfo = prog->aux->linfo;
+
+	/* find first line info to remove, count lines to be removed */
+	for (i = 0; i < nr_linfo; i++)
+		if (linfo[i].insn_off >= off)
+			break;
+
+	l_off = i;
+	l_cnt = 0;
+	for (; i < nr_linfo; i++)
+		if (linfo[i].insn_off < off + cnt)
+			l_cnt++;
+		else
+			break;
+
+	/* First live insn doesn't match first live linfo, it needs to "inherit"
+	 * last removed linfo.  prog is already modified, so prog->len == off
+	 * means no live instructions after (tail of the program was removed).
+	 */
+	if (prog->len != off && l_cnt &&
+	    (i == nr_linfo || linfo[i].insn_off != off + cnt)) {
+		l_cnt--;
+		linfo[--i].insn_off = off + cnt;
+	}
+
+	/* remove the line info which refer to the removed instructions */
+	if (l_cnt) {
+		memmove(linfo + l_off, linfo + i,
+			sizeof(*linfo) * (nr_linfo - i));
+
+		prog->aux->nr_linfo -= l_cnt;
+		nr_linfo = prog->aux->nr_linfo;
+	}
+
+	/* pull all linfo[i].insn_off >= off + cnt in by cnt */
+	for (i = l_off; i < nr_linfo; i++)
+		linfo[i].insn_off -= cnt;
+
+	/* fix up all subprogs (incl. 'exit') which start >= off */
+	for (i = 0; i <= env->subprog_cnt; i++)
+		if (env->subprog_info[i].linfo_idx > l_off) {
+			/* program may have started in the removed region but
+			 * may not be fully removed
+			 */
+			if (env->subprog_info[i].linfo_idx >= l_off + l_cnt)
+				env->subprog_info[i].linfo_idx -= l_cnt;
+			else
+				env->subprog_info[i].linfo_idx = l_off;
+		}
+
+	return 0;
+}
+
+static int verifier_remove_insns(struct bpf_verifier_env *env, u32 off, u32 cnt)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	unsigned int orig_prog_len = env->prog->len;
+	int err;
+
+	if (bpf_prog_is_offloaded(env->prog->aux))
+		bpf_prog_offload_remove_insns(env, off, cnt);
+
+	err = bpf_remove_insns(env->prog, off, cnt);
+	if (err)
+		return err;
+
+	err = adjust_subprog_starts_after_remove(env, off, cnt);
+	if (err)
+		return err;
+
+	err = bpf_adj_linfo_after_remove(env, off, cnt);
+	if (err)
+		return err;
+
+	memmove(aux_data + off,	aux_data + off + cnt,
+		sizeof(*aux_data) * (orig_prog_len - off - cnt));
+
+	return 0;
+}
+
+/* The verifier does more data flow analysis than llvm and will not
+ * explore branches that are dead at run time. Malicious programs can
+ * have dead code too. Therefore replace all dead at-run-time code
+ * with 'ja -1'.
+ *
+ * Just nops are not optimal, e.g. if they would sit at the end of the
+ * program and through another bug we would manage to jump there, then
+ * we'd execute beyond program memory otherwise. Returning exception
+ * code also wouldn't work since we can have subprogs where the dead
+ * code could be located.
+ */
+static void sanitize_dead_code(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	struct bpf_insn trap = BPF_JMP_IMM(BPF_JA, 0, 0, -1);
+	struct bpf_insn *insn = env->prog->insnsi;
+	const int insn_cnt = env->prog->len;
+	int i;
+
+	for (i = 0; i < insn_cnt; i++) {
+		if (aux_data[i].seen)
+			continue;
+		memcpy(insn + i, &trap, sizeof(trap));
+		aux_data[i].zext_dst = false;
+	}
+}
+
+static bool insn_is_cond_jump(u8 code)
+{
+	u8 op;
+
+	op = BPF_OP(code);
+	if (BPF_CLASS(code) == BPF_JMP32)
+		return op != BPF_JA;
+
+	if (BPF_CLASS(code) != BPF_JMP)
+		return false;
+
+	return op != BPF_JA && op != BPF_EXIT && op != BPF_CALL;
+}
+
+static void opt_hard_wire_dead_code_branches(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+	struct bpf_insn *insn = env->prog->insnsi;
+	const int insn_cnt = env->prog->len;
+	int i;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		if (!insn_is_cond_jump(insn->code))
+			continue;
+
+		if (!aux_data[i + 1].seen)
+			ja.off = insn->off;
+		else if (!aux_data[i + 1 + insn->off].seen)
+			ja.off = 0;
+		else
+			continue;
+
+		if (bpf_prog_is_offloaded(env->prog->aux))
+			bpf_prog_offload_replace_insn(env, i, &ja);
+
+		memcpy(insn, &ja, sizeof(ja));
+	}
+}
+
+static int opt_remove_dead_code(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *aux_data = env->insn_aux_data;
+	int insn_cnt = env->prog->len;
+	int i, err;
+
+	for (i = 0; i < insn_cnt; i++) {
+		int j;
+
+		j = 0;
+		while (i + j < insn_cnt && !aux_data[i + j].seen)
+			j++;
+		if (!j)
+			continue;
+
+		err = verifier_remove_insns(env, i, j);
+		if (err)
+			return err;
+		insn_cnt = env->prog->len;
+	}
+
+	return 0;
+}
+
+static int opt_remove_nops(struct bpf_verifier_env *env)
+{
+	const struct bpf_insn ja = BPF_JMP_IMM(BPF_JA, 0, 0, 0);
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	int i, err;
+
+	for (i = 0; i < insn_cnt; i++) {
+		if (memcmp(&insn[i], &ja, sizeof(ja)))
+			continue;
+
+		err = verifier_remove_insns(env, i, 1);
+		if (err)
+			return err;
+		insn_cnt--;
+		i--;
+	}
+
+	return 0;
+}
+
+static int opt_subreg_zext_lo32_rnd_hi32(struct bpf_verifier_env *env,
+					 const union bpf_attr *attr)
+{
+	struct bpf_insn *patch, zext_patch[2], rnd_hi32_patch[4];
+	struct bpf_insn_aux_data *aux = env->insn_aux_data;
+	int i, patch_len, delta = 0, len = env->prog->len;
+	struct bpf_insn *insns = env->prog->insnsi;
+	struct bpf_prog *new_prog;
+	bool rnd_hi32;
+
+	rnd_hi32 = attr->prog_flags & BPF_F_TEST_RND_HI32;
+	zext_patch[1] = BPF_ZEXT_REG(0);
+	rnd_hi32_patch[1] = BPF_ALU64_IMM(BPF_MOV, BPF_REG_AX, 0);
+	rnd_hi32_patch[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_AX, 32);
+	rnd_hi32_patch[3] = BPF_ALU64_REG(BPF_OR, 0, BPF_REG_AX);
+	for (i = 0; i < len; i++) {
+		int adj_idx = i + delta;
+		struct bpf_insn insn;
+		int load_reg;
+
+		insn = insns[adj_idx];
+		load_reg = insn_def_regno(&insn);
+		if (!aux[adj_idx].zext_dst) {
+			u8 code, class;
+			u32 imm_rnd;
+
+			if (!rnd_hi32)
+				continue;
+
+			code = insn.code;
+			class = BPF_CLASS(code);
+			if (load_reg == -1)
+				continue;
+
+			/* NOTE: arg "reg" (the fourth one) is only used for
+			 *       BPF_STX + SRC_OP, so it is safe to pass NULL
+			 *       here.
+			 */
+			if (is_reg64(env, &insn, load_reg, NULL, DST_OP)) {
+				if (class == BPF_LD &&
+				    BPF_MODE(code) == BPF_IMM)
+					i++;
+				continue;
+			}
+
+			/* ctx load could be transformed into wider load. */
+			if (class == BPF_LDX &&
+			    aux[adj_idx].ptr_type == PTR_TO_CTX)
+				continue;
+
+			imm_rnd = get_random_u32();
+			rnd_hi32_patch[0] = insn;
+			rnd_hi32_patch[1].imm = imm_rnd;
+			rnd_hi32_patch[3].dst_reg = load_reg;
+			patch = rnd_hi32_patch;
+			patch_len = 4;
+			goto apply_patch_buffer;
+		}
+
+		/* Add in an zero-extend instruction if a) the JIT has requested
+		 * it or b) it's a CMPXCHG.
+		 *
+		 * The latter is because: BPF_CMPXCHG always loads a value into
+		 * R0, therefore always zero-extends. However some archs'
+		 * equivalent instruction only does this load when the
+		 * comparison is successful. This detail of CMPXCHG is
+		 * orthogonal to the general zero-extension behaviour of the
+		 * CPU, so it's treated independently of bpf_jit_needs_zext.
+		 */
+		if (!bpf_jit_needs_zext() && !is_cmpxchg_insn(&insn))
+			continue;
+
+		/* Zero-extension is done by the caller. */
+		if (bpf_pseudo_kfunc_call(&insn))
+			continue;
+
+		if (WARN_ON(load_reg == -1)) {
+			verbose(env, "verifier bug. zext_dst is set, but no reg is defined\n");
+			return -EFAULT;
+		}
+
+		zext_patch[0] = insn;
+		zext_patch[1].dst_reg = load_reg;
+		zext_patch[1].src_reg = load_reg;
+		patch = zext_patch;
+		patch_len = 2;
+apply_patch_buffer:
+		new_prog = bpf_patch_insn_data(env, adj_idx, patch, patch_len);
+		if (!new_prog)
+			return -ENOMEM;
+		env->prog = new_prog;
+		insns = new_prog->insnsi;
+		aux = env->insn_aux_data;
+		delta += patch_len - 1;
+	}
+
+	return 0;
+}
+
+/* convert load instructions that access fields of a context type into a
+ * sequence of instructions that access fields of the underlying structure:
+ *     struct __sk_buff    -> struct sk_buff
+ *     struct bpf_sock_ops -> struct sock
+ */
+static int convert_ctx_accesses(struct bpf_verifier_env *env)
+{
+	const struct bpf_verifier_ops *ops = env->ops;
+	int i, cnt, size, ctx_field_size, delta = 0;
+	const int insn_cnt = env->prog->len;
+	struct bpf_insn insn_buf[16], *insn;
+	u32 target_size, size_default, off;
+	struct bpf_prog *new_prog;
+	enum bpf_access_type type;
+	bool is_narrower_load;
+
+	if (ops->gen_prologue || env->seen_direct_write) {
+		if (!ops->gen_prologue) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		}
+		cnt = ops->gen_prologue(insn_buf, env->seen_direct_write,
+					env->prog);
+		if (cnt >= ARRAY_SIZE(insn_buf)) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		} else if (cnt) {
+			new_prog = bpf_patch_insn_data(env, 0, insn_buf, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			env->prog = new_prog;
+			delta += cnt - 1;
+		}
+	}
+
+	if (bpf_prog_is_offloaded(env->prog->aux))
+		return 0;
+
+	insn = env->prog->insnsi + delta;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		bpf_convert_ctx_access_t convert_ctx_access;
+		u8 mode;
+
+		if (insn->code == (BPF_LDX | BPF_MEM | BPF_B) ||
+		    insn->code == (BPF_LDX | BPF_MEM | BPF_H) ||
+		    insn->code == (BPF_LDX | BPF_MEM | BPF_W) ||
+		    insn->code == (BPF_LDX | BPF_MEM | BPF_DW) ||
+		    insn->code == (BPF_LDX | BPF_MEMSX | BPF_B) ||
+		    insn->code == (BPF_LDX | BPF_MEMSX | BPF_H) ||
+		    insn->code == (BPF_LDX | BPF_MEMSX | BPF_W)) {
+			type = BPF_READ;
+		} else if (insn->code == (BPF_STX | BPF_MEM | BPF_B) ||
+			   insn->code == (BPF_STX | BPF_MEM | BPF_H) ||
+			   insn->code == (BPF_STX | BPF_MEM | BPF_W) ||
+			   insn->code == (BPF_STX | BPF_MEM | BPF_DW) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_B) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_H) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_W) ||
+			   insn->code == (BPF_ST | BPF_MEM | BPF_DW)) {
+			type = BPF_WRITE;
+		} else {
+			continue;
+		}
+
+		if (type == BPF_WRITE &&
+		    env->insn_aux_data[i + delta].sanitize_stack_spill) {
+			struct bpf_insn patch[] = {
+				*insn,
+				BPF_ST_NOSPEC(),
+			};
+
+			cnt = ARRAY_SIZE(patch);
+			new_prog = bpf_patch_insn_data(env, i + delta, patch, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		switch ((int)env->insn_aux_data[i + delta].ptr_type) {
+		case PTR_TO_CTX:
+			if (!ops->convert_ctx_access)
+				continue;
+			convert_ctx_access = ops->convert_ctx_access;
+			break;
+		case PTR_TO_SOCKET:
+		case PTR_TO_SOCK_COMMON:
+			convert_ctx_access = bpf_sock_convert_ctx_access;
+			break;
+		case PTR_TO_TCP_SOCK:
+			convert_ctx_access = bpf_tcp_sock_convert_ctx_access;
+			break;
+		case PTR_TO_XDP_SOCK:
+			convert_ctx_access = bpf_xdp_sock_convert_ctx_access;
+			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) {
+				if (BPF_MODE(insn->code) == BPF_MEM)
+					insn->code = BPF_LDX | BPF_PROBE_MEM |
+						     BPF_SIZE((insn)->code);
+				else
+					insn->code = BPF_LDX | BPF_PROBE_MEMSX |
+						     BPF_SIZE((insn)->code);
+				env->prog->aux->num_exentries++;
+			}
+			continue;
+		default:
+			continue;
+		}
+
+		ctx_field_size = env->insn_aux_data[i + delta].ctx_field_size;
+		size = BPF_LDST_BYTES(insn);
+		mode = BPF_MODE(insn->code);
+
+		/* If the read access is a narrower load of the field,
+		 * convert to a 4/8-byte load, to minimum program type specific
+		 * convert_ctx_access changes. If conversion is successful,
+		 * we will apply proper mask to the result.
+		 */
+		is_narrower_load = size < ctx_field_size;
+		size_default = bpf_ctx_off_adjust_machine(ctx_field_size);
+		off = insn->off;
+		if (is_narrower_load) {
+			u8 size_code;
+
+			if (type == BPF_WRITE) {
+				verbose(env, "bpf verifier narrow ctx access misconfigured\n");
+				return -EINVAL;
+			}
+
+			size_code = BPF_H;
+			if (ctx_field_size == 4)
+				size_code = BPF_W;
+			else if (ctx_field_size == 8)
+				size_code = BPF_DW;
+
+			insn->off = off & ~(size_default - 1);
+			insn->code = BPF_LDX | BPF_MEM | size_code;
+		}
+
+		target_size = 0;
+		cnt = convert_ctx_access(type, insn, insn_buf, env->prog,
+					 &target_size);
+		if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf) ||
+		    (ctx_field_size && !target_size)) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		}
+
+		if (is_narrower_load && size < target_size) {
+			u8 shift = bpf_ctx_narrow_access_offset(
+				off, size, size_default) * 8;
+			if (shift && cnt + 1 >= ARRAY_SIZE(insn_buf)) {
+				verbose(env, "bpf verifier narrow ctx load misconfigured\n");
+				return -EINVAL;
+			}
+			if (ctx_field_size <= 4) {
+				if (shift)
+					insn_buf[cnt++] = BPF_ALU32_IMM(BPF_RSH,
+									insn->dst_reg,
+									shift);
+				insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
+								(1 << size * 8) - 1);
+			} else {
+				if (shift)
+					insn_buf[cnt++] = BPF_ALU64_IMM(BPF_RSH,
+									insn->dst_reg,
+									shift);
+				insn_buf[cnt++] = BPF_ALU32_IMM(BPF_AND, insn->dst_reg,
+								(1ULL << size * 8) - 1);
+			}
+		}
+		if (mode == BPF_MEMSX)
+			insn_buf[cnt++] = BPF_RAW_INSN(BPF_ALU64 | BPF_MOV | BPF_X,
+						       insn->dst_reg, insn->dst_reg,
+						       size * 8, 0);
+
+		new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, cnt);
+		if (!new_prog)
+			return -ENOMEM;
+
+		delta += cnt - 1;
+
+		/* keep walking new program and skip insns we just inserted */
+		env->prog = new_prog;
+		insn      = new_prog->insnsi + i + delta;
+	}
+
+	return 0;
+}
+
+static int jit_subprogs(struct bpf_verifier_env *env)
+{
+	struct bpf_prog *prog = env->prog, **func, *tmp;
+	int i, j, subprog_start, subprog_end = 0, len, subprog;
+	struct bpf_map *map_ptr;
+	struct bpf_insn *insn;
+	void *old_bpf_func;
+	int err, num_exentries;
+
+	if (env->subprog_cnt <= 1)
+		return 0;
+
+	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+		if (!bpf_pseudo_func(insn) && !bpf_pseudo_call(insn))
+			continue;
+
+		/* Upon error here we cannot fall back to interpreter but
+		 * need a hard reject of the program. Thus -EFAULT is
+		 * propagated in any case.
+		 */
+		subprog = find_subprog(env, i + insn->imm + 1);
+		if (subprog < 0) {
+			WARN_ONCE(1, "verifier bug. No program starts at insn %d\n",
+				  i + insn->imm + 1);
+			return -EFAULT;
+		}
+		/* temporarily remember subprog id inside insn instead of
+		 * aux_data, since next loop will split up all insns into funcs
+		 */
+		insn->off = subprog;
+		/* remember original imm in case JIT fails and fallback
+		 * to interpreter will be needed
+		 */
+		env->insn_aux_data[i].call_imm = insn->imm;
+		/* point imm to __bpf_call_base+1 from JITs point of view */
+		insn->imm = 1;
+		if (bpf_pseudo_func(insn))
+			/* jit (e.g. x86_64) may emit fewer instructions
+			 * if it learns a u32 imm is the same as a u64 imm.
+			 * Force a non zero here.
+			 */
+			insn[1].imm = 1;
+	}
+
+	err = bpf_prog_alloc_jited_linfo(prog);
+	if (err)
+		goto out_undo_insn;
+
+	err = -ENOMEM;
+	func = kcalloc(env->subprog_cnt, sizeof(prog), GFP_KERNEL);
+	if (!func)
+		goto out_undo_insn;
+
+	for (i = 0; i < env->subprog_cnt; i++) {
+		subprog_start = subprog_end;
+		subprog_end = env->subprog_info[i + 1].start;
+
+		len = subprog_end - subprog_start;
+		/* bpf_prog_run() doesn't call subprogs directly,
+		 * hence main prog stats include the runtime of subprogs.
+		 * subprogs don't have IDs and not reachable via prog_get_next_id
+		 * func[i]->stats will never be accessed and stays NULL
+		 */
+		func[i] = bpf_prog_alloc_no_stats(bpf_prog_size(len), GFP_USER);
+		if (!func[i])
+			goto out_free;
+		memcpy(func[i]->insnsi, &prog->insnsi[subprog_start],
+		       len * sizeof(struct bpf_insn));
+		func[i]->type = prog->type;
+		func[i]->len = len;
+		if (bpf_prog_calc_tag(func[i]))
+			goto out_free;
+		func[i]->is_func = 1;
+		func[i]->aux->func_idx = i;
+		/* Below members will be freed only at prog->aux */
+		func[i]->aux->btf = prog->aux->btf;
+		func[i]->aux->func_info = prog->aux->func_info;
+		func[i]->aux->func_info_cnt = prog->aux->func_info_cnt;
+		func[i]->aux->poke_tab = prog->aux->poke_tab;
+		func[i]->aux->size_poke_tab = prog->aux->size_poke_tab;
+
+		for (j = 0; j < prog->aux->size_poke_tab; j++) {
+			struct bpf_jit_poke_descriptor *poke;
+
+			poke = &prog->aux->poke_tab[j];
+			if (poke->insn_idx < subprog_end &&
+			    poke->insn_idx >= subprog_start)
+				poke->aux = func[i]->aux;
+		}
+
+		func[i]->aux->name[0] = 'F';
+		func[i]->aux->stack_depth = env->subprog_info[i].stack_depth;
+		func[i]->jit_requested = 1;
+		func[i]->blinding_requested = prog->blinding_requested;
+		func[i]->aux->kfunc_tab = prog->aux->kfunc_tab;
+		func[i]->aux->kfunc_btf_tab = prog->aux->kfunc_btf_tab;
+		func[i]->aux->linfo = prog->aux->linfo;
+		func[i]->aux->nr_linfo = prog->aux->nr_linfo;
+		func[i]->aux->jited_linfo = prog->aux->jited_linfo;
+		func[i]->aux->linfo_idx = env->subprog_info[i].linfo_idx;
+		num_exentries = 0;
+		insn = func[i]->insnsi;
+		for (j = 0; j < func[i]->len; j++, insn++) {
+			if (BPF_CLASS(insn->code) == BPF_LDX &&
+			    (BPF_MODE(insn->code) == BPF_PROBE_MEM ||
+			     BPF_MODE(insn->code) == BPF_PROBE_MEMSX))
+				num_exentries++;
+		}
+		func[i]->aux->num_exentries = num_exentries;
+		func[i]->aux->tail_call_reachable = env->subprog_info[i].tail_call_reachable;
+		func[i] = bpf_int_jit_compile(func[i]);
+		if (!func[i]->jited) {
+			err = -ENOTSUPP;
+			goto out_free;
+		}
+		cond_resched();
+	}
+
+	/* at this point all bpf functions were successfully JITed
+	 * now populate all bpf_calls with correct addresses and
+	 * run last pass of JIT
+	 */
+	for (i = 0; i < env->subprog_cnt; i++) {
+		insn = func[i]->insnsi;
+		for (j = 0; j < func[i]->len; j++, insn++) {
+			if (bpf_pseudo_func(insn)) {
+				subprog = insn->off;
+				insn[0].imm = (u32)(long)func[subprog]->bpf_func;
+				insn[1].imm = ((u64)(long)func[subprog]->bpf_func) >> 32;
+				continue;
+			}
+			if (!bpf_pseudo_call(insn))
+				continue;
+			subprog = insn->off;
+			insn->imm = BPF_CALL_IMM(func[subprog]->bpf_func);
+		}
+
+		/* we use the aux data to keep a list of the start addresses
+		 * of the JITed images for each function in the program
+		 *
+		 * for some architectures, such as powerpc64, the imm field
+		 * might not be large enough to hold the offset of the start
+		 * address of the callee's JITed image from __bpf_call_base
+		 *
+		 * in such cases, we can lookup the start address of a callee
+		 * by using its subprog id, available from the off field of
+		 * the call instruction, as an index for this list
+		 */
+		func[i]->aux->func = func;
+		func[i]->aux->func_cnt = env->subprog_cnt;
+	}
+	for (i = 0; i < env->subprog_cnt; i++) {
+		old_bpf_func = func[i]->bpf_func;
+		tmp = bpf_int_jit_compile(func[i]);
+		if (tmp != func[i] || func[i]->bpf_func != old_bpf_func) {
+			verbose(env, "JIT doesn't support bpf-to-bpf calls\n");
+			err = -ENOTSUPP;
+			goto out_free;
+		}
+		cond_resched();
+	}
+
+	/* finally lock prog and jit images for all functions and
+	 * populate kallsysm. Begin at the first subprogram, since
+	 * bpf_prog_load will add the kallsyms for the main program.
+	 */
+	for (i = 1; i < env->subprog_cnt; i++) {
+		bpf_prog_lock_ro(func[i]);
+		bpf_prog_kallsyms_add(func[i]);
+	}
+
+	/* Last step: make now unused interpreter insns from main
+	 * prog consistent for later dump requests, so they can
+	 * later look the same as if they were interpreted only.
+	 */
+	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+		if (bpf_pseudo_func(insn)) {
+			insn[0].imm = env->insn_aux_data[i].call_imm;
+			insn[1].imm = insn->off;
+			insn->off = 0;
+			continue;
+		}
+		if (!bpf_pseudo_call(insn))
+			continue;
+		insn->off = env->insn_aux_data[i].call_imm;
+		subprog = find_subprog(env, i + insn->off + 1);
+		insn->imm = subprog;
+	}
+
+	prog->jited = 1;
+	prog->bpf_func = func[0]->bpf_func;
+	prog->jited_len = func[0]->jited_len;
+	prog->aux->extable = func[0]->aux->extable;
+	prog->aux->num_exentries = func[0]->aux->num_exentries;
+	prog->aux->func = func;
+	prog->aux->func_cnt = env->subprog_cnt;
+	bpf_prog_jit_attempt_done(prog);
+	return 0;
+out_free:
+	/* We failed JIT'ing, so at this point we need to unregister poke
+	 * descriptors from subprogs, so that kernel is not attempting to
+	 * patch it anymore as we're freeing the subprog JIT memory.
+	 */
+	for (i = 0; i < prog->aux->size_poke_tab; i++) {
+		map_ptr = prog->aux->poke_tab[i].tail_call.map;
+		map_ptr->ops->map_poke_untrack(map_ptr, prog->aux);
+	}
+	/* At this point we're guaranteed that poke descriptors are not
+	 * live anymore. We can just unlink its descriptor table as it's
+	 * released with the main prog.
+	 */
+	for (i = 0; i < env->subprog_cnt; i++) {
+		if (!func[i])
+			continue;
+		func[i]->aux->poke_tab = NULL;
+		bpf_jit_free(func[i]);
+	}
+	kfree(func);
+out_undo_insn:
+	/* cleanup main prog to be interpreted */
+	prog->jit_requested = 0;
+	prog->blinding_requested = 0;
+	for (i = 0, insn = prog->insnsi; i < prog->len; i++, insn++) {
+		if (!bpf_pseudo_call(insn))
+			continue;
+		insn->off = 0;
+		insn->imm = env->insn_aux_data[i].call_imm;
+	}
+	bpf_prog_jit_attempt_done(prog);
+	return err;
+}
+
+static int fixup_call_args(struct bpf_verifier_env *env)
+{
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+	struct bpf_prog *prog = env->prog;
+	struct bpf_insn *insn = prog->insnsi;
+	bool has_kfunc_call = bpf_prog_has_kfunc_call(prog);
+	int i, depth;
+#endif
+	int err = 0;
+
+	if (env->prog->jit_requested &&
+	    !bpf_prog_is_offloaded(env->prog->aux)) {
+		err = jit_subprogs(env);
+		if (err == 0)
+			return 0;
+		if (err == -EFAULT)
+			return err;
+	}
+#ifndef CONFIG_BPF_JIT_ALWAYS_ON
+	if (has_kfunc_call) {
+		verbose(env, "calling kernel functions are not allowed in non-JITed programs\n");
+		return -EINVAL;
+	}
+	if (env->subprog_cnt > 1 && env->prog->aux->tail_call_reachable) {
+		/* When JIT fails the progs with bpf2bpf calls and tail_calls
+		 * have to be rejected, since interpreter doesn't support them yet.
+		 */
+		verbose(env, "tail_calls are not allowed in non-JITed programs with bpf-to-bpf calls\n");
+		return -EINVAL;
+	}
+	for (i = 0; i < prog->len; i++, insn++) {
+		if (bpf_pseudo_func(insn)) {
+			/* When JIT fails the progs with callback calls
+			 * have to be rejected, since interpreter doesn't support them yet.
+			 */
+			verbose(env, "callbacks are not allowed in non-JITed programs\n");
+			return -EINVAL;
+		}
+
+		if (!bpf_pseudo_call(insn))
+			continue;
+		depth = get_callee_stack_depth(env, insn, i);
+		if (depth < 0)
+			return depth;
+		bpf_patch_call_args(insn, depth);
+	}
+	err = 0;
+#endif
+	return err;
+}
+
+/* replace a generic kfunc with a specialized version if necessary */
+static void specialize_kfunc(struct bpf_verifier_env *env,
+			     u32 func_id, u16 offset, unsigned long *addr)
+{
+	struct bpf_prog *prog = env->prog;
+	bool seen_direct_write;
+	void *xdp_kfunc;
+	bool is_rdonly;
+
+	if (bpf_dev_bound_kfunc_id(func_id)) {
+		xdp_kfunc = bpf_dev_bound_resolve_kfunc(prog, func_id);
+		if (xdp_kfunc) {
+			*addr = (unsigned long)xdp_kfunc;
+			return;
+		}
+		/* fallback to default kfunc when not supported by netdev */
+	}
+
+	if (offset)
+		return;
+
+	if (func_id == special_kfunc_list[KF_bpf_dynptr_from_skb]) {
+		seen_direct_write = env->seen_direct_write;
+		is_rdonly = !may_access_direct_pkt_data(env, NULL, BPF_WRITE);
+
+		if (is_rdonly)
+			*addr = (unsigned long)bpf_dynptr_from_skb_rdonly;
+
+		/* restore env->seen_direct_write to its original value, since
+		 * may_access_direct_pkt_data mutates it
+		 */
+		env->seen_direct_write = seen_direct_write;
+	}
+}
+
+static void __fixup_collection_insert_kfunc(struct bpf_insn_aux_data *insn_aux,
+					    u16 struct_meta_reg,
+					    u16 node_offset_reg,
+					    struct bpf_insn *insn,
+					    struct bpf_insn *insn_buf,
+					    int *cnt)
+{
+	struct btf_struct_meta *kptr_struct_meta = insn_aux->kptr_struct_meta;
+	struct bpf_insn addr[2] = { BPF_LD_IMM64(struct_meta_reg, (long)kptr_struct_meta) };
+
+	insn_buf[0] = addr[0];
+	insn_buf[1] = addr[1];
+	insn_buf[2] = BPF_MOV64_IMM(node_offset_reg, insn_aux->insert_off);
+	insn_buf[3] = *insn;
+	*cnt = 4;
+}
+
+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;
+
+	if (!insn->imm) {
+		verbose(env, "invalid kernel function call not eliminated in verifier pass\n");
+		return -EINVAL;
+	}
+
+	*cnt = 0;
+
+	/* insn->imm has the btf func_id. Replace it with an offset relative to
+	 * __bpf_call_base, unless the JIT needs to call functions that are
+	 * further than 32 bits away (bpf_jit_supports_far_kfunc_call()).
+	 */
+	desc = find_kfunc_desc(env->prog, insn->imm, insn->off);
+	if (!desc) {
+		verbose(env, "verifier internal error: kernel function descriptor not found for func_id %u\n",
+			insn->imm);
+		return -EFAULT;
+	}
+
+	if (!bpf_jit_supports_far_kfunc_call())
+		insn->imm = BPF_CALL_IMM(desc->addr);
+	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] ||
+		   desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_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) };
+
+		if (desc->func_id == special_kfunc_list[KF_bpf_refcount_acquire_impl] &&
+		    !kptr_struct_meta) {
+			verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n",
+				insn_idx);
+			return -EFAULT;
+		}
+
+		insn_buf[0] = addr[0];
+		insn_buf[1] = addr[1];
+		insn_buf[2] = *insn;
+		*cnt = 3;
+	} else if (desc->func_id == special_kfunc_list[KF_bpf_list_push_back_impl] ||
+		   desc->func_id == special_kfunc_list[KF_bpf_list_push_front_impl] ||
+		   desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+		struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
+		int struct_meta_reg = BPF_REG_3;
+		int node_offset_reg = BPF_REG_4;
+
+		/* rbtree_add has extra 'less' arg, so args-to-fixup are in diff regs */
+		if (desc->func_id == special_kfunc_list[KF_bpf_rbtree_add_impl]) {
+			struct_meta_reg = BPF_REG_4;
+			node_offset_reg = BPF_REG_5;
+		}
+
+		if (!kptr_struct_meta) {
+			verbose(env, "verifier internal error: kptr_struct_meta expected at insn_idx %d\n",
+				insn_idx);
+			return -EFAULT;
+		}
+
+		__fixup_collection_insert_kfunc(&env->insn_aux_data[insn_idx], struct_meta_reg,
+						node_offset_reg, insn, insn_buf, cnt);
+	} else if (desc->func_id == special_kfunc_list[KF_bpf_cast_to_kern_ctx] ||
+		   desc->func_id == special_kfunc_list[KF_bpf_rdonly_cast]) {
+		insn_buf[0] = BPF_MOV64_REG(BPF_REG_0, BPF_REG_1);
+		*cnt = 1;
+	}
+	return 0;
+}
+
+/* Do various post-verification rewrites in a single program pass.
+ * These rewrites simplify JIT and interpreter implementations.
+ */
+static int do_misc_fixups(struct bpf_verifier_env *env)
+{
+	struct bpf_prog *prog = env->prog;
+	enum bpf_attach_type eatype = prog->expected_attach_type;
+	enum bpf_prog_type prog_type = resolve_prog_type(prog);
+	struct bpf_insn *insn = prog->insnsi;
+	const struct bpf_func_proto *fn;
+	const int insn_cnt = prog->len;
+	const struct bpf_map_ops *ops;
+	struct bpf_insn_aux_data *aux;
+	struct bpf_insn insn_buf[16];
+	struct bpf_prog *new_prog;
+	struct bpf_map *map_ptr;
+	int i, ret, cnt, delta = 0;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		/* Make divide-by-zero exceptions impossible. */
+		if (insn->code == (BPF_ALU64 | BPF_MOD | BPF_X) ||
+		    insn->code == (BPF_ALU64 | BPF_DIV | BPF_X) ||
+		    insn->code == (BPF_ALU | BPF_MOD | BPF_X) ||
+		    insn->code == (BPF_ALU | BPF_DIV | BPF_X)) {
+			bool is64 = BPF_CLASS(insn->code) == BPF_ALU64;
+			bool isdiv = BPF_OP(insn->code) == BPF_DIV;
+			struct bpf_insn *patchlet;
+			struct bpf_insn chk_and_div[] = {
+				/* [R,W]x div 0 -> 0 */
+				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+					     BPF_JNE | BPF_K, insn->src_reg,
+					     0, 2, 0),
+				BPF_ALU32_REG(BPF_XOR, insn->dst_reg, insn->dst_reg),
+				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+				*insn,
+			};
+			struct bpf_insn chk_and_mod[] = {
+				/* [R,W]x mod 0 -> [R,W]x */
+				BPF_RAW_INSN((is64 ? BPF_JMP : BPF_JMP32) |
+					     BPF_JEQ | BPF_K, insn->src_reg,
+					     0, 1 + (is64 ? 0 : 1), 0),
+				*insn,
+				BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+				BPF_MOV32_REG(insn->dst_reg, insn->dst_reg),
+			};
+
+			patchlet = isdiv ? chk_and_div : chk_and_mod;
+			cnt = isdiv ? ARRAY_SIZE(chk_and_div) :
+				      ARRAY_SIZE(chk_and_mod) - (is64 ? 2 : 0);
+
+			new_prog = bpf_patch_insn_data(env, i + delta, patchlet, cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta    += cnt - 1;
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Implement LD_ABS and LD_IND with a rewrite, if supported by the program type. */
+		if (BPF_CLASS(insn->code) == BPF_LD &&
+		    (BPF_MODE(insn->code) == BPF_ABS ||
+		     BPF_MODE(insn->code) == BPF_IND)) {
+			cnt = env->ops->gen_ld_abs(insn, insn_buf);
+			if (cnt == 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+				verbose(env, "bpf verifier is misconfigured\n");
+				return -EINVAL;
+			}
+
+			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;
+		}
+
+		/* Rewrite pointer arithmetic to mitigate speculation attacks. */
+		if (insn->code == (BPF_ALU64 | BPF_ADD | BPF_X) ||
+		    insn->code == (BPF_ALU64 | BPF_SUB | BPF_X)) {
+			const u8 code_add = BPF_ALU64 | BPF_ADD | BPF_X;
+			const u8 code_sub = BPF_ALU64 | BPF_SUB | BPF_X;
+			struct bpf_insn *patch = &insn_buf[0];
+			bool issrc, isneg, isimm;
+			u32 off_reg;
+
+			aux = &env->insn_aux_data[i + delta];
+			if (!aux->alu_state ||
+			    aux->alu_state == BPF_ALU_NON_POINTER)
+				continue;
+
+			isneg = aux->alu_state & BPF_ALU_NEG_VALUE;
+			issrc = (aux->alu_state & BPF_ALU_SANITIZE) ==
+				BPF_ALU_SANITIZE_SRC;
+			isimm = aux->alu_state & BPF_ALU_IMMEDIATE;
+
+			off_reg = issrc ? insn->src_reg : insn->dst_reg;
+			if (isimm) {
+				*patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+			} else {
+				if (isneg)
+					*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+				*patch++ = BPF_MOV32_IMM(BPF_REG_AX, aux->alu_limit);
+				*patch++ = BPF_ALU64_REG(BPF_SUB, BPF_REG_AX, off_reg);
+				*patch++ = BPF_ALU64_REG(BPF_OR, BPF_REG_AX, off_reg);
+				*patch++ = BPF_ALU64_IMM(BPF_NEG, BPF_REG_AX, 0);
+				*patch++ = BPF_ALU64_IMM(BPF_ARSH, BPF_REG_AX, 63);
+				*patch++ = BPF_ALU64_REG(BPF_AND, BPF_REG_AX, off_reg);
+			}
+			if (!issrc)
+				*patch++ = BPF_MOV64_REG(insn->dst_reg, insn->src_reg);
+			insn->src_reg = BPF_REG_AX;
+			if (isneg)
+				insn->code = insn->code == code_add ?
+					     code_sub : code_add;
+			*patch++ = *insn;
+			if (issrc && isneg && !isimm)
+				*patch++ = BPF_ALU64_IMM(BPF_MUL, off_reg, -1);
+			cnt = patch - insn_buf;
+
+			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;
+		}
+
+		if (insn->code != (BPF_JMP | BPF_CALL))
+			continue;
+		if (insn->src_reg == BPF_PSEUDO_CALL)
+			continue;
+		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
+			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;
+		}
+
+		if (insn->imm == BPF_FUNC_get_route_realm)
+			prog->dst_needed = 1;
+		if (insn->imm == BPF_FUNC_get_prandom_u32)
+			bpf_user_rnd_init_once();
+		if (insn->imm == BPF_FUNC_override_return)
+			prog->kprobe_override = 1;
+		if (insn->imm == BPF_FUNC_tail_call) {
+			/* If we tail call into other programs, we
+			 * cannot make any assumptions since they can
+			 * be replaced dynamically during runtime in
+			 * the program array.
+			 */
+			prog->cb_access = 1;
+			if (!allow_tail_call_in_subprogs(env))
+				prog->aux->stack_depth = MAX_BPF_STACK;
+			prog->aux->max_pkt_offset = MAX_PACKET_OFF;
+
+			/* mark bpf_tail_call as different opcode to avoid
+			 * conditional branch in the interpreter for every normal
+			 * call and to prevent accidental JITing by JIT compiler
+			 * that doesn't support bpf_tail_call yet
+			 */
+			insn->imm = 0;
+			insn->code = BPF_JMP | BPF_TAIL_CALL;
+
+			aux = &env->insn_aux_data[i + delta];
+			if (env->bpf_capable && !prog->blinding_requested &&
+			    prog->jit_requested &&
+			    !bpf_map_key_poisoned(aux) &&
+			    !bpf_map_ptr_poisoned(aux) &&
+			    !bpf_map_ptr_unpriv(aux)) {
+				struct bpf_jit_poke_descriptor desc = {
+					.reason = BPF_POKE_REASON_TAIL_CALL,
+					.tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
+					.tail_call.key = bpf_map_key_immediate(aux),
+					.insn_idx = i + delta,
+				};
+
+				ret = bpf_jit_add_poke_descriptor(prog, &desc);
+				if (ret < 0) {
+					verbose(env, "adding tail call poke descriptor failed\n");
+					return ret;
+				}
+
+				insn->imm = ret + 1;
+				continue;
+			}
+
+			if (!bpf_map_ptr_unpriv(aux))
+				continue;
+
+			/* instead of changing every JIT dealing with tail_call
+			 * emit two extra insns:
+			 * if (index >= max_entries) goto out;
+			 * index &= array->index_mask;
+			 * to avoid out-of-bounds cpu speculation
+			 */
+			if (bpf_map_ptr_poisoned(aux)) {
+				verbose(env, "tail_call abusing map_ptr\n");
+				return -EINVAL;
+			}
+
+			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
+			insn_buf[0] = BPF_JMP_IMM(BPF_JGE, BPF_REG_3,
+						  map_ptr->max_entries, 2);
+			insn_buf[1] = BPF_ALU32_IMM(BPF_AND, BPF_REG_3,
+						    container_of(map_ptr,
+								 struct bpf_array,
+								 map)->index_mask);
+			insn_buf[2] = *insn;
+			cnt = 3;
+			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;
+		}
+
+		if (insn->imm == BPF_FUNC_timer_set_callback) {
+			/* The verifier will process callback_fn as many times as necessary
+			 * with different maps and the register states prepared by
+			 * set_timer_callback_state will be accurate.
+			 *
+			 * The following use case is valid:
+			 *   map1 is shared by prog1, prog2, prog3.
+			 *   prog1 calls bpf_timer_init for some map1 elements
+			 *   prog2 calls bpf_timer_set_callback for some map1 elements.
+			 *     Those that were not bpf_timer_init-ed will return -EINVAL.
+			 *   prog3 calls bpf_timer_start for some map1 elements.
+			 *     Those that were not both bpf_timer_init-ed and
+			 *     bpf_timer_set_callback-ed will return -EINVAL.
+			 */
+			struct bpf_insn ld_addrs[2] = {
+				BPF_LD_IMM64(BPF_REG_3, (long)prog->aux),
+			};
+
+			insn_buf[0] = ld_addrs[0];
+			insn_buf[1] = ld_addrs[1];
+			insn_buf[2] = *insn;
+			cnt = 3;
+
+			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;
+			goto patch_call_imm;
+		}
+
+		if (is_storage_get_function(insn->imm)) {
+			if (!env->prog->aux->sleepable ||
+			    env->insn_aux_data[i + delta].storage_get_func_atomic)
+				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_ATOMIC);
+			else
+				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_5, (__force __s32)GFP_KERNEL);
+			insn_buf[1] = *insn;
+			cnt = 2;
+
+			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;
+			goto patch_call_imm;
+		}
+
+		/* BPF_EMIT_CALL() assumptions in some of the map_gen_lookup
+		 * and other inlining handlers are currently limited to 64 bit
+		 * only.
+		 */
+		if (prog->jit_requested && BITS_PER_LONG == 64 &&
+		    (insn->imm == BPF_FUNC_map_lookup_elem ||
+		     insn->imm == BPF_FUNC_map_update_elem ||
+		     insn->imm == BPF_FUNC_map_delete_elem ||
+		     insn->imm == BPF_FUNC_map_push_elem   ||
+		     insn->imm == BPF_FUNC_map_pop_elem    ||
+		     insn->imm == BPF_FUNC_map_peek_elem   ||
+		     insn->imm == BPF_FUNC_redirect_map    ||
+		     insn->imm == BPF_FUNC_for_each_map_elem ||
+		     insn->imm == BPF_FUNC_map_lookup_percpu_elem)) {
+			aux = &env->insn_aux_data[i + delta];
+			if (bpf_map_ptr_poisoned(aux))
+				goto patch_call_imm;
+
+			map_ptr = BPF_MAP_PTR(aux->map_ptr_state);
+			ops = map_ptr->ops;
+			if (insn->imm == BPF_FUNC_map_lookup_elem &&
+			    ops->map_gen_lookup) {
+				cnt = ops->map_gen_lookup(map_ptr, insn_buf);
+				if (cnt == -EOPNOTSUPP)
+					goto patch_map_ops_generic;
+				if (cnt <= 0 || cnt >= ARRAY_SIZE(insn_buf)) {
+					verbose(env, "bpf verifier is misconfigured\n");
+					return -EINVAL;
+				}
+
+				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;
+			}
+
+			BUILD_BUG_ON(!__same_type(ops->map_lookup_elem,
+				     (void *(*)(struct bpf_map *map, void *key))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_delete_elem,
+				     (long (*)(struct bpf_map *map, void *key))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_update_elem,
+				     (long (*)(struct bpf_map *map, void *key, void *value,
+					      u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_push_elem,
+				     (long (*)(struct bpf_map *map, void *value,
+					      u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_pop_elem,
+				     (long (*)(struct bpf_map *map, void *value))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_peek_elem,
+				     (long (*)(struct bpf_map *map, void *value))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_redirect,
+				     (long (*)(struct bpf_map *map, u64 index, u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_for_each_callback,
+				     (long (*)(struct bpf_map *map,
+					      bpf_callback_t callback_fn,
+					      void *callback_ctx,
+					      u64 flags))NULL));
+			BUILD_BUG_ON(!__same_type(ops->map_lookup_percpu_elem,
+				     (void *(*)(struct bpf_map *map, void *key, u32 cpu))NULL));
+
+patch_map_ops_generic:
+			switch (insn->imm) {
+			case BPF_FUNC_map_lookup_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_lookup_elem);
+				continue;
+			case BPF_FUNC_map_update_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_update_elem);
+				continue;
+			case BPF_FUNC_map_delete_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_delete_elem);
+				continue;
+			case BPF_FUNC_map_push_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_push_elem);
+				continue;
+			case BPF_FUNC_map_pop_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_pop_elem);
+				continue;
+			case BPF_FUNC_map_peek_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_peek_elem);
+				continue;
+			case BPF_FUNC_redirect_map:
+				insn->imm = BPF_CALL_IMM(ops->map_redirect);
+				continue;
+			case BPF_FUNC_for_each_map_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_for_each_callback);
+				continue;
+			case BPF_FUNC_map_lookup_percpu_elem:
+				insn->imm = BPF_CALL_IMM(ops->map_lookup_percpu_elem);
+				continue;
+			}
+
+			goto patch_call_imm;
+		}
+
+		/* Implement bpf_jiffies64 inline. */
+		if (prog->jit_requested && BITS_PER_LONG == 64 &&
+		    insn->imm == BPF_FUNC_jiffies64) {
+			struct bpf_insn ld_jiffies_addr[2] = {
+				BPF_LD_IMM64(BPF_REG_0,
+					     (unsigned long)&jiffies),
+			};
+
+			insn_buf[0] = ld_jiffies_addr[0];
+			insn_buf[1] = ld_jiffies_addr[1];
+			insn_buf[2] = BPF_LDX_MEM(BPF_DW, BPF_REG_0,
+						  BPF_REG_0, 0);
+			cnt = 3;
+
+			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;
+		}
+
+		/* Implement bpf_get_func_arg inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_arg) {
+			/* Load nr_args from ctx - 8 */
+			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+			insn_buf[1] = BPF_JMP32_REG(BPF_JGE, BPF_REG_2, BPF_REG_0, 6);
+			insn_buf[2] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_2, 3);
+			insn_buf[3] = BPF_ALU64_REG(BPF_ADD, BPF_REG_2, BPF_REG_1);
+			insn_buf[4] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_2, 0);
+			insn_buf[5] = BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
+			insn_buf[6] = BPF_MOV64_IMM(BPF_REG_0, 0);
+			insn_buf[7] = BPF_JMP_A(1);
+			insn_buf[8] = BPF_MOV64_IMM(BPF_REG_0, -EINVAL);
+			cnt = 9;
+
+			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;
+		}
+
+		/* Implement bpf_get_func_ret inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_ret) {
+			if (eatype == BPF_TRACE_FEXIT ||
+			    eatype == BPF_MODIFY_RETURN) {
+				/* Load nr_args from ctx - 8 */
+				insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+				insn_buf[1] = BPF_ALU64_IMM(BPF_LSH, BPF_REG_0, 3);
+				insn_buf[2] = BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1);
+				insn_buf[3] = BPF_LDX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, 0);
+				insn_buf[4] = BPF_STX_MEM(BPF_DW, BPF_REG_2, BPF_REG_3, 0);
+				insn_buf[5] = BPF_MOV64_IMM(BPF_REG_0, 0);
+				cnt = 6;
+			} else {
+				insn_buf[0] = BPF_MOV64_IMM(BPF_REG_0, -EOPNOTSUPP);
+				cnt = 1;
+			}
+
+			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;
+		}
+
+		/* Implement get_func_arg_cnt inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_arg_cnt) {
+			/* Load nr_args from ctx - 8 */
+			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -8);
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
+			if (!new_prog)
+				return -ENOMEM;
+
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+		/* Implement bpf_get_func_ip inline. */
+		if (prog_type == BPF_PROG_TYPE_TRACING &&
+		    insn->imm == BPF_FUNC_get_func_ip) {
+			/* Load IP address from ctx - 16 */
+			insn_buf[0] = BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_1, -16);
+
+			new_prog = bpf_patch_insn_data(env, i + delta, insn_buf, 1);
+			if (!new_prog)
+				return -ENOMEM;
+
+			env->prog = prog = new_prog;
+			insn      = new_prog->insnsi + i + delta;
+			continue;
+		}
+
+patch_call_imm:
+		fn = env->ops->get_func_proto(insn->imm, env->prog);
+		/* all functions that have prototype and verifier allowed
+		 * programs to call them, must be real in-kernel functions
+		 */
+		if (!fn->func) {
+			verbose(env,
+				"kernel subsystem misconfigured func %s#%d\n",
+				func_id_name(insn->imm), insn->imm);
+			return -EFAULT;
+		}
+		insn->imm = fn->func - __bpf_call_base;
+	}
+
+	/* Since poke tab is now finalized, publish aux to tracker. */
+	for (i = 0; i < prog->aux->size_poke_tab; i++) {
+		map_ptr = prog->aux->poke_tab[i].tail_call.map;
+		if (!map_ptr->ops->map_poke_track ||
+		    !map_ptr->ops->map_poke_untrack ||
+		    !map_ptr->ops->map_poke_run) {
+			verbose(env, "bpf verifier is misconfigured\n");
+			return -EINVAL;
+		}
+
+		ret = map_ptr->ops->map_poke_track(map_ptr, prog->aux);
+		if (ret < 0) {
+			verbose(env, "tracking tail call prog failed\n");
+			return ret;
+		}
+	}
+
+	sort_kfunc_descs_by_imm_off(env->prog);
+
+	return 0;
+}
+
+static struct bpf_prog *inline_bpf_loop(struct bpf_verifier_env *env,
+					int position,
+					s32 stack_base,
+					u32 callback_subprogno,
+					u32 *cnt)
+{
+	s32 r6_offset = stack_base + 0 * BPF_REG_SIZE;
+	s32 r7_offset = stack_base + 1 * BPF_REG_SIZE;
+	s32 r8_offset = stack_base + 2 * BPF_REG_SIZE;
+	int reg_loop_max = BPF_REG_6;
+	int reg_loop_cnt = BPF_REG_7;
+	int reg_loop_ctx = BPF_REG_8;
+
+	struct bpf_prog *new_prog;
+	u32 callback_start;
+	u32 call_insn_offset;
+	s32 callback_offset;
+
+	/* This represents an inlined version of bpf_iter.c:bpf_loop,
+	 * be careful to modify this code in sync.
+	 */
+	struct bpf_insn insn_buf[] = {
+		/* Return error and jump to the end of the patch if
+		 * expected number of iterations is too big.
+		 */
+		BPF_JMP_IMM(BPF_JLE, BPF_REG_1, BPF_MAX_LOOPS, 2),
+		BPF_MOV32_IMM(BPF_REG_0, -E2BIG),
+		BPF_JMP_IMM(BPF_JA, 0, 0, 16),
+		/* spill R6, R7, R8 to use these as loop vars */
+		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_6, r6_offset),
+		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_7, r7_offset),
+		BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_8, r8_offset),
+		/* initialize loop vars */
+		BPF_MOV64_REG(reg_loop_max, BPF_REG_1),
+		BPF_MOV32_IMM(reg_loop_cnt, 0),
+		BPF_MOV64_REG(reg_loop_ctx, BPF_REG_3),
+		/* loop header,
+		 * if reg_loop_cnt >= reg_loop_max skip the loop body
+		 */
+		BPF_JMP_REG(BPF_JGE, reg_loop_cnt, reg_loop_max, 5),
+		/* callback call,
+		 * correct callback offset would be set after patching
+		 */
+		BPF_MOV64_REG(BPF_REG_1, reg_loop_cnt),
+		BPF_MOV64_REG(BPF_REG_2, reg_loop_ctx),
+		BPF_CALL_REL(0),
+		/* increment loop counter */
+		BPF_ALU64_IMM(BPF_ADD, reg_loop_cnt, 1),
+		/* jump to loop header if callback returned 0 */
+		BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -6),
+		/* return value of bpf_loop,
+		 * set R0 to the number of iterations
+		 */
+		BPF_MOV64_REG(BPF_REG_0, reg_loop_cnt),
+		/* restore original values of R6, R7, R8 */
+		BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_10, r6_offset),
+		BPF_LDX_MEM(BPF_DW, BPF_REG_7, BPF_REG_10, r7_offset),
+		BPF_LDX_MEM(BPF_DW, BPF_REG_8, BPF_REG_10, r8_offset),
+	};
+
+	*cnt = ARRAY_SIZE(insn_buf);
+	new_prog = bpf_patch_insn_data(env, position, insn_buf, *cnt);
+	if (!new_prog)
+		return new_prog;
+
+	/* callback start is known only after patching */
+	callback_start = env->subprog_info[callback_subprogno].start;
+	/* Note: insn_buf[12] is an offset of BPF_CALL_REL instruction */
+	call_insn_offset = position + 12;
+	callback_offset = callback_start - call_insn_offset - 1;
+	new_prog->insnsi[call_insn_offset].imm = callback_offset;
+
+	return new_prog;
+}
+
+static bool is_bpf_loop_call(struct bpf_insn *insn)
+{
+	return insn->code == (BPF_JMP | BPF_CALL) &&
+		insn->src_reg == 0 &&
+		insn->imm == BPF_FUNC_loop;
+}
+
+/* For all sub-programs in the program (including main) check
+ * insn_aux_data to see if there are bpf_loop calls that require
+ * inlining. If such calls are found the calls are replaced with a
+ * sequence of instructions produced by `inline_bpf_loop` function and
+ * subprog stack_depth is increased by the size of 3 registers.
+ * This stack space is used to spill values of the R6, R7, R8.  These
+ * registers are used to store the loop bound, counter and context
+ * variables.
+ */
+static int optimize_bpf_loop(struct bpf_verifier_env *env)
+{
+	struct bpf_subprog_info *subprogs = env->subprog_info;
+	int i, cur_subprog = 0, cnt, delta = 0;
+	struct bpf_insn *insn = env->prog->insnsi;
+	int insn_cnt = env->prog->len;
+	u16 stack_depth = subprogs[cur_subprog].stack_depth;
+	u16 stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
+	u16 stack_depth_extra = 0;
+
+	for (i = 0; i < insn_cnt; i++, insn++) {
+		struct bpf_loop_inline_state *inline_state =
+			&env->insn_aux_data[i + delta].loop_inline_state;
+
+		if (is_bpf_loop_call(insn) && inline_state->fit_for_inline) {
+			struct bpf_prog *new_prog;
+
+			stack_depth_extra = BPF_REG_SIZE * 3 + stack_depth_roundup;
+			new_prog = inline_bpf_loop(env,
+						   i + delta,
+						   -(stack_depth + stack_depth_extra),
+						   inline_state->callback_subprogno,
+						   &cnt);
+			if (!new_prog)
+				return -ENOMEM;
+
+			delta     += cnt - 1;
+			env->prog  = new_prog;
+			insn       = new_prog->insnsi + i + delta;
+		}
+
+		if (subprogs[cur_subprog + 1].start == i + delta + 1) {
+			subprogs[cur_subprog].stack_depth += stack_depth_extra;
+			cur_subprog++;
+			stack_depth = subprogs[cur_subprog].stack_depth;
+			stack_depth_roundup = round_up(stack_depth, 8) - stack_depth;
+			stack_depth_extra = 0;
+		}
+	}
+
+	env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
+
+	return 0;
+}
+
+static void free_states(struct bpf_verifier_env *env)
+{
+	struct bpf_verifier_state_list *sl, *sln;
+	int i;
+
+	sl = env->free_list;
+	while (sl) {
+		sln = sl->next;
+		free_verifier_state(&sl->state, false);
+		kfree(sl);
+		sl = sln;
+	}
+	env->free_list = NULL;
+
+	if (!env->explored_states)
+		return;
+
+	for (i = 0; i < state_htab_size(env); i++) {
+		sl = env->explored_states[i];
+
+		while (sl) {
+			sln = sl->next;
+			free_verifier_state(&sl->state, false);
+			kfree(sl);
+			sl = sln;
+		}
+		env->explored_states[i] = NULL;
+	}
+}
+
+static int do_check_common(struct bpf_verifier_env *env, int subprog)
+{
+	bool pop_log = !(env->log.level & BPF_LOG_LEVEL2);
+	struct bpf_verifier_state *state;
+	struct bpf_reg_state *regs;
+	int ret, i;
+
+	env->prev_linfo = NULL;
+	env->pass_cnt++;
+
+	state = kzalloc(sizeof(struct bpf_verifier_state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+	state->curframe = 0;
+	state->speculative = false;
+	state->branches = 1;
+	state->frame[0] = kzalloc(sizeof(struct bpf_func_state), GFP_KERNEL);
+	if (!state->frame[0]) {
+		kfree(state);
+		return -ENOMEM;
+	}
+	env->cur_state = state;
+	init_func_state(env, state->frame[0],
+			BPF_MAIN_FUNC /* callsite */,
+			0 /* frameno */,
+			subprog);
+	state->first_insn_idx = env->subprog_info[subprog].start;
+	state->last_insn_idx = -1;
+
+	regs = state->frame[state->curframe]->regs;
+	if (subprog || env->prog->type == BPF_PROG_TYPE_EXT) {
+		ret = btf_prepare_func_args(env, subprog, regs);
+		if (ret)
+			goto out;
+		for (i = BPF_REG_1; i <= BPF_REG_5; i++) {
+			if (regs[i].type == PTR_TO_CTX)
+				mark_reg_known_zero(env, regs, i);
+			else if (regs[i].type == SCALAR_VALUE)
+				mark_reg_unknown(env, regs, i);
+			else if (base_type(regs[i].type) == PTR_TO_MEM) {
+				const u32 mem_size = regs[i].mem_size;
+
+				mark_reg_known_zero(env, regs, i);
+				regs[i].mem_size = mem_size;
+				regs[i].id = ++env->id_gen;
+			}
+		}
+	} else {
+		/* 1st arg to a function */
+		regs[BPF_REG_1].type = PTR_TO_CTX;
+		mark_reg_known_zero(env, regs, BPF_REG_1);
+		ret = btf_check_subprog_arg_match(env, subprog, regs);
+		if (ret == -EFAULT)
+			/* unlikely verifier bug. abort.
+			 * ret == 0 and ret < 0 are sadly acceptable for
+			 * main() function due to backward compatibility.
+			 * Like socket filter program may be written as:
+			 * int bpf_prog(struct pt_regs *ctx)
+			 * and never dereference that ctx in the program.
+			 * 'struct pt_regs' is a type mismatch for socket
+			 * filter that should be using 'struct __sk_buff'.
+			 */
+			goto out;
+	}
+
+	ret = do_check(env);
+out:
+	/* check for NULL is necessary, since cur_state can be freed inside
+	 * do_check() under memory pressure.
+	 */
+	if (env->cur_state) {
+		free_verifier_state(env->cur_state, true);
+		env->cur_state = NULL;
+	}
+	while (!pop_stack(env, NULL, NULL, false));
+	if (!ret && pop_log)
+		bpf_vlog_reset(&env->log, 0);
+	free_states(env);
+	return ret;
+}
+
+/* Verify all global functions in a BPF program one by one based on their BTF.
+ * All global functions must pass verification. Otherwise the whole program is rejected.
+ * Consider:
+ * int bar(int);
+ * int foo(int f)
+ * {
+ *    return bar(f);
+ * }
+ * int bar(int b)
+ * {
+ *    ...
+ * }
+ * foo() will be verified first for R1=any_scalar_value. During verification it
+ * will be assumed that bar() already verified successfully and call to bar()
+ * from foo() will be checked for type match only. Later bar() will be verified
+ * independently to check that it's safe for R1=any_scalar_value.
+ */
+static int do_check_subprogs(struct bpf_verifier_env *env)
+{
+	struct bpf_prog_aux *aux = env->prog->aux;
+	int i, ret;
+
+	if (!aux->func_info)
+		return 0;
+
+	for (i = 1; i < env->subprog_cnt; i++) {
+		if (aux->func_info_aux[i].linkage != BTF_FUNC_GLOBAL)
+			continue;
+		env->insn_idx = env->subprog_info[i].start;
+		WARN_ON_ONCE(env->insn_idx == 0);
+		ret = do_check_common(env, i);
+		if (ret) {
+			return ret;
+		} else if (env->log.level & BPF_LOG_LEVEL) {
+			verbose(env,
+				"Func#%d is safe for any args that match its prototype\n",
+				i);
+		}
+	}
+	return 0;
+}
+
+static int do_check_main(struct bpf_verifier_env *env)
+{
+	int ret;
+
+	env->insn_idx = 0;
+	ret = do_check_common(env, 0);
+	if (!ret)
+		env->prog->aux->stack_depth = env->subprog_info[0].stack_depth;
+	return ret;
+}
+
+
+static void print_verification_stats(struct bpf_verifier_env *env)
+{
+	int i;
+
+	if (env->log.level & BPF_LOG_STATS) {
+		verbose(env, "verification time %lld usec\n",
+			div_u64(env->verification_time, 1000));
+		verbose(env, "stack depth ");
+		for (i = 0; i < env->subprog_cnt; i++) {
+			u32 depth = env->subprog_info[i].stack_depth;
+
+			verbose(env, "%d", depth);
+			if (i + 1 < env->subprog_cnt)
+				verbose(env, "+");
+		}
+		verbose(env, "\n");
+	}
+	verbose(env, "processed %d insns (limit %d) max_states_per_insn %d "
+		"total_states %d peak_states %d mark_read %d\n",
+		env->insn_processed, BPF_COMPLEXITY_LIMIT_INSNS,
+		env->max_states_per_insn, env->total_states,
+		env->peak_states, env->longest_mark_read_walk);
+}
+
+static int check_struct_ops_btf_id(struct bpf_verifier_env *env)
+{
+	const struct btf_type *t, *func_proto;
+	const struct bpf_struct_ops *st_ops;
+	const struct btf_member *member;
+	struct bpf_prog *prog = env->prog;
+	u32 btf_id, member_idx;
+	const char *mname;
+
+	if (!prog->gpl_compatible) {
+		verbose(env, "struct ops programs must have a GPL compatible license\n");
+		return -EINVAL;
+	}
+
+	btf_id = prog->aux->attach_btf_id;
+	st_ops = bpf_struct_ops_find(btf_id);
+	if (!st_ops) {
+		verbose(env, "attach_btf_id %u is not a supported struct\n",
+			btf_id);
+		return -ENOTSUPP;
+	}
+
+	t = st_ops->type;
+	member_idx = prog->expected_attach_type;
+	if (member_idx >= btf_type_vlen(t)) {
+		verbose(env, "attach to invalid member idx %u of struct %s\n",
+			member_idx, st_ops->name);
+		return -EINVAL;
+	}
+
+	member = &btf_type_member(t)[member_idx];
+	mname = btf_name_by_offset(btf_vmlinux, member->name_off);
+	func_proto = btf_type_resolve_func_ptr(btf_vmlinux, member->type,
+					       NULL);
+	if (!func_proto) {
+		verbose(env, "attach to invalid member %s(@idx %u) of struct %s\n",
+			mname, member_idx, st_ops->name);
+		return -EINVAL;
+	}
+
+	if (st_ops->check_member) {
+		int err = st_ops->check_member(t, member, prog);
+
+		if (err) {
+			verbose(env, "attach to unsupported member %s of struct %s\n",
+				mname, st_ops->name);
+			return err;
+		}
+	}
+
+	prog->aux->attach_func_proto = func_proto;
+	prog->aux->attach_func_name = mname;
+	env->ops = st_ops->verifier_ops;
+
+	return 0;
+}
+#define SECURITY_PREFIX "security_"
+
+static int check_attach_modify_return(unsigned long addr, const char *func_name)
+{
+	if (within_error_injection_list(addr) ||
+	    !strncmp(SECURITY_PREFIX, func_name, sizeof(SECURITY_PREFIX) - 1))
+		return 0;
+
+	return -EINVAL;
+}
+
+/* list of non-sleepable functions that are otherwise on
+ * ALLOW_ERROR_INJECTION list
+ */
+BTF_SET_START(btf_non_sleepable_error_inject)
+/* Three functions below can be called from sleepable and non-sleepable context.
+ * Assume non-sleepable from bpf safety point of view.
+ */
+BTF_ID(func, __filemap_add_folio)
+BTF_ID(func, should_fail_alloc_page)
+BTF_ID(func, should_failslab)
+BTF_SET_END(btf_non_sleepable_error_inject)
+
+static int check_non_sleepable_error_inject(u32 btf_id)
+{
+	return btf_id_set_contains(&btf_non_sleepable_error_inject, btf_id);
+}
+
+int bpf_check_attach_target(struct bpf_verifier_log *log,
+			    const struct bpf_prog *prog,
+			    const struct bpf_prog *tgt_prog,
+			    u32 btf_id,
+			    struct bpf_attach_target_info *tgt_info)
+{
+	bool prog_extension = prog->type == BPF_PROG_TYPE_EXT;
+	const char prefix[] = "btf_trace_";
+	int ret = 0, subprog = -1, i;
+	const struct btf_type *t;
+	bool conservative = true;
+	const char *tname;
+	struct btf *btf;
+	long addr = 0;
+	struct module *mod = NULL;
+
+	if (!btf_id) {
+		bpf_log(log, "Tracing programs must provide btf_id\n");
+		return -EINVAL;
+	}
+	btf = tgt_prog ? tgt_prog->aux->btf : prog->aux->attach_btf;
+	if (!btf) {
+		bpf_log(log,
+			"FENTRY/FEXIT program can only be attached to another program annotated with BTF\n");
+		return -EINVAL;
+	}
+	t = btf_type_by_id(btf, btf_id);
+	if (!t) {
+		bpf_log(log, "attach_btf_id %u is invalid\n", btf_id);
+		return -EINVAL;
+	}
+	tname = btf_name_by_offset(btf, t->name_off);
+	if (!tname) {
+		bpf_log(log, "attach_btf_id %u doesn't have a name\n", btf_id);
+		return -EINVAL;
+	}
+	if (tgt_prog) {
+		struct bpf_prog_aux *aux = tgt_prog->aux;
+
+		if (bpf_prog_is_dev_bound(prog->aux) &&
+		    !bpf_prog_dev_bound_match(prog, tgt_prog)) {
+			bpf_log(log, "Target program bound device mismatch");
+			return -EINVAL;
+		}
+
+		for (i = 0; i < aux->func_info_cnt; i++)
+			if (aux->func_info[i].type_id == btf_id) {
+				subprog = i;
+				break;
+			}
+		if (subprog == -1) {
+			bpf_log(log, "Subprog %s doesn't exist\n", tname);
+			return -EINVAL;
+		}
+		conservative = aux->func_info_aux[subprog].unreliable;
+		if (prog_extension) {
+			if (conservative) {
+				bpf_log(log,
+					"Cannot replace static functions\n");
+				return -EINVAL;
+			}
+			if (!prog->jit_requested) {
+				bpf_log(log,
+					"Extension programs should be JITed\n");
+				return -EINVAL;
+			}
+		}
+		if (!tgt_prog->jited) {
+			bpf_log(log, "Can attach to only JITed progs\n");
+			return -EINVAL;
+		}
+		if (tgt_prog->type == prog->type) {
+			/* Cannot fentry/fexit another fentry/fexit program.
+			 * Cannot attach program extension to another extension.
+			 * It's ok to attach fentry/fexit to extension program.
+			 */
+			bpf_log(log, "Cannot recursively attach\n");
+			return -EINVAL;
+		}
+		if (tgt_prog->type == BPF_PROG_TYPE_TRACING &&
+		    prog_extension &&
+		    (tgt_prog->expected_attach_type == BPF_TRACE_FENTRY ||
+		     tgt_prog->expected_attach_type == BPF_TRACE_FEXIT)) {
+			/* Program extensions can extend all program types
+			 * except fentry/fexit. The reason is the following.
+			 * The fentry/fexit programs are used for performance
+			 * analysis, stats and can be attached to any program
+			 * type except themselves. When extension program is
+			 * replacing XDP function it is necessary to allow
+			 * performance analysis of all functions. Both original
+			 * XDP program and its program extension. Hence
+			 * attaching fentry/fexit to BPF_PROG_TYPE_EXT is
+			 * allowed. If extending of fentry/fexit was allowed it
+			 * would be possible to create long call chain
+			 * fentry->extension->fentry->extension beyond
+			 * reasonable stack size. Hence extending fentry is not
+			 * allowed.
+			 */
+			bpf_log(log, "Cannot extend fentry/fexit\n");
+			return -EINVAL;
+		}
+	} else {
+		if (prog_extension) {
+			bpf_log(log, "Cannot replace kernel functions\n");
+			return -EINVAL;
+		}
+	}
+
+	switch (prog->expected_attach_type) {
+	case BPF_TRACE_RAW_TP:
+		if (tgt_prog) {
+			bpf_log(log,
+				"Only FENTRY/FEXIT progs are attachable to another BPF prog\n");
+			return -EINVAL;
+		}
+		if (!btf_type_is_typedef(t)) {
+			bpf_log(log, "attach_btf_id %u is not a typedef\n",
+				btf_id);
+			return -EINVAL;
+		}
+		if (strncmp(prefix, tname, sizeof(prefix) - 1)) {
+			bpf_log(log, "attach_btf_id %u points to wrong type name %s\n",
+				btf_id, tname);
+			return -EINVAL;
+		}
+		tname += sizeof(prefix) - 1;
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_ptr(t))
+			/* should never happen in valid vmlinux build */
+			return -EINVAL;
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_func_proto(t))
+			/* should never happen in valid vmlinux build */
+			return -EINVAL;
+
+		break;
+	case BPF_TRACE_ITER:
+		if (!btf_type_is_func(t)) {
+			bpf_log(log, "attach_btf_id %u is not a function\n",
+				btf_id);
+			return -EINVAL;
+		}
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_func_proto(t))
+			return -EINVAL;
+		ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
+		if (ret)
+			return ret;
+		break;
+	default:
+		if (!prog_extension)
+			return -EINVAL;
+		fallthrough;
+	case BPF_MODIFY_RETURN:
+	case BPF_LSM_MAC:
+	case BPF_LSM_CGROUP:
+	case BPF_TRACE_FENTRY:
+	case BPF_TRACE_FEXIT:
+		if (!btf_type_is_func(t)) {
+			bpf_log(log, "attach_btf_id %u is not a function\n",
+				btf_id);
+			return -EINVAL;
+		}
+		if (prog_extension &&
+		    btf_check_type_match(log, prog, btf, t))
+			return -EINVAL;
+		t = btf_type_by_id(btf, t->type);
+		if (!btf_type_is_func_proto(t))
+			return -EINVAL;
+
+		if ((prog->aux->saved_dst_prog_type || prog->aux->saved_dst_attach_type) &&
+		    (!tgt_prog || prog->aux->saved_dst_prog_type != tgt_prog->type ||
+		     prog->aux->saved_dst_attach_type != tgt_prog->expected_attach_type))
+			return -EINVAL;
+
+		if (tgt_prog && conservative)
+			t = NULL;
+
+		ret = btf_distill_func_proto(log, btf, t, tname, &tgt_info->fmodel);
+		if (ret < 0)
+			return ret;
+
+		if (tgt_prog) {
+			if (subprog == 0)
+				addr = (long) tgt_prog->bpf_func;
+			else
+				addr = (long) tgt_prog->aux->func[subprog]->bpf_func;
+		} else {
+			if (btf_is_module(btf)) {
+				mod = btf_try_get_module(btf);
+				if (mod)
+					addr = find_kallsyms_symbol_value(mod, tname);
+				else
+					addr = 0;
+			} else {
+				addr = kallsyms_lookup_name(tname);
+			}
+			if (!addr) {
+				module_put(mod);
+				bpf_log(log,
+					"The address of function %s cannot be found\n",
+					tname);
+				return -ENOENT;
+			}
+		}
+
+		if (prog->aux->sleepable) {
+			ret = -EINVAL;
+			switch (prog->type) {
+			case BPF_PROG_TYPE_TRACING:
+
+				/* fentry/fexit/fmod_ret progs can be sleepable if they are
+				 * attached to ALLOW_ERROR_INJECTION and are not in denylist.
+				 */
+				if (!check_non_sleepable_error_inject(btf_id) &&
+				    within_error_injection_list(addr))
+					ret = 0;
+				/* fentry/fexit/fmod_ret progs can also be sleepable if they are
+				 * in the fmodret id set with the KF_SLEEPABLE flag.
+				 */
+				else {
+					u32 *flags = btf_kfunc_is_modify_return(btf, btf_id,
+										prog);
+
+					if (flags && (*flags & KF_SLEEPABLE))
+						ret = 0;
+				}
+				break;
+			case BPF_PROG_TYPE_LSM:
+				/* LSM progs check that they are attached to bpf_lsm_*() funcs.
+				 * Only some of them are sleepable.
+				 */
+				if (bpf_lsm_is_sleepable_hook(btf_id))
+					ret = 0;
+				break;
+			default:
+				break;
+			}
+			if (ret) {
+				module_put(mod);
+				bpf_log(log, "%s is not sleepable\n", tname);
+				return ret;
+			}
+		} else if (prog->expected_attach_type == BPF_MODIFY_RETURN) {
+			if (tgt_prog) {
+				module_put(mod);
+				bpf_log(log, "can't modify return codes of BPF programs\n");
+				return -EINVAL;
+			}
+			ret = -EINVAL;
+			if (btf_kfunc_is_modify_return(btf, btf_id, prog) ||
+			    !check_attach_modify_return(addr, tname))
+				ret = 0;
+			if (ret) {
+				module_put(mod);
+				bpf_log(log, "%s() is not modifiable\n", tname);
+				return ret;
+			}
+		}
+
+		break;
+	}
+	tgt_info->tgt_addr = addr;
+	tgt_info->tgt_name = tname;
+	tgt_info->tgt_type = t;
+	tgt_info->tgt_mod = mod;
+	return 0;
+}
+
+BTF_SET_START(btf_id_deny)
+BTF_ID_UNUSED
+#ifdef CONFIG_SMP
+BTF_ID(func, migrate_disable)
+BTF_ID(func, migrate_enable)
+#endif
+#if !defined CONFIG_PREEMPT_RCU && !defined CONFIG_TINY_RCU
+BTF_ID(func, rcu_read_unlock_strict)
+#endif
+#if defined(CONFIG_DEBUG_PREEMPT) || defined(CONFIG_TRACE_PREEMPT_TOGGLE)
+BTF_ID(func, preempt_count_add)
+BTF_ID(func, preempt_count_sub)
+#endif
+#ifdef CONFIG_PREEMPT_RCU
+BTF_ID(func, __rcu_read_lock)
+BTF_ID(func, __rcu_read_unlock)
+#endif
+BTF_SET_END(btf_id_deny)
+
+static bool can_be_sleepable(struct bpf_prog *prog)
+{
+	if (prog->type == BPF_PROG_TYPE_TRACING) {
+		switch (prog->expected_attach_type) {
+		case BPF_TRACE_FENTRY:
+		case BPF_TRACE_FEXIT:
+		case BPF_MODIFY_RETURN:
+		case BPF_TRACE_ITER:
+			return true;
+		default:
+			return false;
+		}
+	}
+	return prog->type == BPF_PROG_TYPE_LSM ||
+	       prog->type == BPF_PROG_TYPE_KPROBE /* only for uprobes */ ||
+	       prog->type == BPF_PROG_TYPE_STRUCT_OPS;
+}
+
+static int check_attach_btf_id(struct bpf_verifier_env *env)
+{
+	struct bpf_prog *prog = env->prog;
+	struct bpf_prog *tgt_prog = prog->aux->dst_prog;
+	struct bpf_attach_target_info tgt_info = {};
+	u32 btf_id = prog->aux->attach_btf_id;
+	struct bpf_trampoline *tr;
+	int ret;
+	u64 key;
+
+	if (prog->type == BPF_PROG_TYPE_SYSCALL) {
+		if (prog->aux->sleepable)
+			/* attach_btf_id checked to be zero already */
+			return 0;
+		verbose(env, "Syscall programs can only be sleepable\n");
+		return -EINVAL;
+	}
+
+	if (prog->aux->sleepable && !can_be_sleepable(prog)) {
+		verbose(env, "Only fentry/fexit/fmod_ret, lsm, iter, uprobe, and struct_ops programs can be sleepable\n");
+		return -EINVAL;
+	}
+
+	if (prog->type == BPF_PROG_TYPE_STRUCT_OPS)
+		return check_struct_ops_btf_id(env);
+
+	if (prog->type != BPF_PROG_TYPE_TRACING &&
+	    prog->type != BPF_PROG_TYPE_LSM &&
+	    prog->type != BPF_PROG_TYPE_EXT)
+		return 0;
+
+	ret = bpf_check_attach_target(&env->log, prog, tgt_prog, btf_id, &tgt_info);
+	if (ret)
+		return ret;
+
+	if (tgt_prog && prog->type == BPF_PROG_TYPE_EXT) {
+		/* to make freplace equivalent to their targets, they need to
+		 * inherit env->ops and expected_attach_type for the rest of the
+		 * verification
+		 */
+		env->ops = bpf_verifier_ops[tgt_prog->type];
+		prog->expected_attach_type = tgt_prog->expected_attach_type;
+	}
+
+	/* store info about the attachment target that will be used later */
+	prog->aux->attach_func_proto = tgt_info.tgt_type;
+	prog->aux->attach_func_name = tgt_info.tgt_name;
+	prog->aux->mod = tgt_info.tgt_mod;
+
+	if (tgt_prog) {
+		prog->aux->saved_dst_prog_type = tgt_prog->type;
+		prog->aux->saved_dst_attach_type = tgt_prog->expected_attach_type;
+	}
+
+	if (prog->expected_attach_type == BPF_TRACE_RAW_TP) {
+		prog->aux->attach_btf_trace = true;
+		return 0;
+	} else if (prog->expected_attach_type == BPF_TRACE_ITER) {
+		if (!bpf_iter_prog_supported(prog))
+			return -EINVAL;
+		return 0;
+	}
+
+	if (prog->type == BPF_PROG_TYPE_LSM) {
+		ret = bpf_lsm_verify_prog(&env->log, prog);
+		if (ret < 0)
+			return ret;
+	} else if (prog->type == BPF_PROG_TYPE_TRACING &&
+		   btf_id_set_contains(&btf_id_deny, btf_id)) {
+		return -EINVAL;
+	}
+
+	key = bpf_trampoline_compute_key(tgt_prog, prog->aux->attach_btf, btf_id);
+	tr = bpf_trampoline_get(key, &tgt_info);
+	if (!tr)
+		return -ENOMEM;
+
+	if (tgt_prog && tgt_prog->aux->tail_call_reachable)
+		tr->flags = BPF_TRAMP_F_TAIL_CALL_CTX;
+
+	prog->aux->dst_trampoline = tr;
+	return 0;
+}
+
+struct btf *bpf_get_btf_vmlinux(void)
+{
+	if (!btf_vmlinux && IS_ENABLED(CONFIG_DEBUG_INFO_BTF)) {
+		mutex_lock(&bpf_verifier_lock);
+		if (!btf_vmlinux)
+			btf_vmlinux = btf_parse_vmlinux();
+		mutex_unlock(&bpf_verifier_lock);
+	}
+	return btf_vmlinux;
+}
+
+int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr, __u32 uattr_size)
+{
+	u64 start_time = ktime_get_ns();
+	struct bpf_verifier_env *env;
+	int i, len, ret = -EINVAL, err;
+	u32 log_true_size;
+	bool is_priv;
+
+	/* no program is valid */
+	if (ARRAY_SIZE(bpf_verifier_ops) == 0)
+		return -EINVAL;
+
+	/* 'struct bpf_verifier_env' can be global, but since it's not small,
+	 * allocate/free it every time bpf_check() is called
+	 */
+	env = kzalloc(sizeof(struct bpf_verifier_env), GFP_KERNEL);
+	if (!env)
+		return -ENOMEM;
+
+	env->bt.env = env;
+
+	len = (*prog)->len;
+	env->insn_aux_data =
+		vzalloc(array_size(sizeof(struct bpf_insn_aux_data), len));
+	ret = -ENOMEM;
+	if (!env->insn_aux_data)
+		goto err_free_env;
+	for (i = 0; i < len; i++)
+		env->insn_aux_data[i].orig_idx = i;
+	env->prog = *prog;
+	env->ops = bpf_verifier_ops[env->prog->type];
+	env->fd_array = make_bpfptr(attr->fd_array, uattr.is_kernel);
+	is_priv = bpf_capable();
+
+	bpf_get_btf_vmlinux();
+
+	/* grab the mutex to protect few globals used by verifier */
+	if (!is_priv)
+		mutex_lock(&bpf_verifier_lock);
+
+	/* user could have requested verbose verifier output
+	 * and supplied buffer to store the verification trace
+	 */
+	ret = bpf_vlog_init(&env->log, attr->log_level,
+			    (char __user *) (unsigned long) attr->log_buf,
+			    attr->log_size);
+	if (ret)
+		goto err_unlock;
+
+	mark_verifier_state_clean(env);
+
+	if (IS_ERR(btf_vmlinux)) {
+		/* Either gcc or pahole or kernel are broken. */
+		verbose(env, "in-kernel BTF is malformed\n");
+		ret = PTR_ERR(btf_vmlinux);
+		goto skip_full_check;
+	}
+
+	env->strict_alignment = !!(attr->prog_flags & BPF_F_STRICT_ALIGNMENT);
+	if (!IS_ENABLED(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS))
+		env->strict_alignment = true;
+	if (attr->prog_flags & BPF_F_ANY_ALIGNMENT)
+		env->strict_alignment = false;
+
+	env->allow_ptr_leaks = bpf_allow_ptr_leaks();
+	env->allow_uninit_stack = bpf_allow_uninit_stack();
+	env->bypass_spec_v1 = bpf_bypass_spec_v1();
+	env->bypass_spec_v4 = bpf_bypass_spec_v4();
+	env->bpf_capable = bpf_capable();
+
+	if (is_priv)
+		env->test_state_freq = attr->prog_flags & BPF_F_TEST_STATE_FREQ;
+
+	env->explored_states = kvcalloc(state_htab_size(env),
+				       sizeof(struct bpf_verifier_state_list *),
+				       GFP_USER);
+	ret = -ENOMEM;
+	if (!env->explored_states)
+		goto skip_full_check;
+
+	ret = add_subprog_and_kfunc(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = check_subprogs(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = check_btf_info(env, attr, uattr);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = check_attach_btf_id(env);
+	if (ret)
+		goto skip_full_check;
+
+	ret = resolve_pseudo_ldimm64(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	if (bpf_prog_is_offloaded(env->prog->aux)) {
+		ret = bpf_prog_offload_verifier_prep(env->prog);
+		if (ret)
+			goto skip_full_check;
+	}
+
+	ret = check_cfg(env);
+	if (ret < 0)
+		goto skip_full_check;
+
+	ret = do_check_subprogs(env);
+	ret = ret ?: do_check_main(env);
+
+	if (ret == 0 && bpf_prog_is_offloaded(env->prog->aux))
+		ret = bpf_prog_offload_finalize(env);
+
+skip_full_check:
+	kvfree(env->explored_states);
+
+	if (ret == 0)
+		ret = check_max_stack_depth(env);
+
+	/* instruction rewrites happen after this point */
+	if (ret == 0)
+		ret = optimize_bpf_loop(env);
+
+	if (is_priv) {
+		if (ret == 0)
+			opt_hard_wire_dead_code_branches(env);
+		if (ret == 0)
+			ret = opt_remove_dead_code(env);
+		if (ret == 0)
+			ret = opt_remove_nops(env);
+	} else {
+		if (ret == 0)
+			sanitize_dead_code(env);
+	}
+
+	if (ret == 0)
+		/* program is valid, convert *(u32*)(ctx + off) accesses */
+		ret = convert_ctx_accesses(env);
+
+	if (ret == 0)
+		ret = do_misc_fixups(env);
+
+	/* do 32-bit optimization after insn patching has done so those patched
+	 * insns could be handled correctly.
+	 */
+	if (ret == 0 && !bpf_prog_is_offloaded(env->prog->aux)) {
+		ret = opt_subreg_zext_lo32_rnd_hi32(env, attr);
+		env->prog->aux->verifier_zext = bpf_jit_needs_zext() ? !ret
+								     : false;
+	}
+
+	if (ret == 0)
+		ret = fixup_call_args(env);
+
+	env->verification_time = ktime_get_ns() - start_time;
+	print_verification_stats(env);
+	env->prog->aux->verified_insns = env->insn_processed;
+
+	/* preserve original error even if log finalization is successful */
+	err = bpf_vlog_finalize(&env->log, &log_true_size);
+	if (err)
+		ret = err;
+
+	if (uattr_size >= offsetofend(union bpf_attr, log_true_size) &&
+	    copy_to_bpfptr_offset(uattr, offsetof(union bpf_attr, log_true_size),
+				  &log_true_size, sizeof(log_true_size))) {
+		ret = -EFAULT;
+		goto err_release_maps;
+	}
+
+	if (ret)
+		goto err_release_maps;
+
+	if (env->used_map_cnt) {
+		/* if program passed verifier, update used_maps in bpf_prog_info */
+		env->prog->aux->used_maps = kmalloc_array(env->used_map_cnt,
+							  sizeof(env->used_maps[0]),
+							  GFP_KERNEL);
+
+		if (!env->prog->aux->used_maps) {
+			ret = -ENOMEM;
+			goto err_release_maps;
+		}
+
+		memcpy(env->prog->aux->used_maps, env->used_maps,
+		       sizeof(env->used_maps[0]) * env->used_map_cnt);
+		env->prog->aux->used_map_cnt = env->used_map_cnt;
+	}
+	if (env->used_btf_cnt) {
+		/* if program passed verifier, update used_btfs in bpf_prog_aux */
+		env->prog->aux->used_btfs = kmalloc_array(env->used_btf_cnt,
+							  sizeof(env->used_btfs[0]),
+							  GFP_KERNEL);
+		if (!env->prog->aux->used_btfs) {
+			ret = -ENOMEM;
+			goto err_release_maps;
+		}
+
+		memcpy(env->prog->aux->used_btfs, env->used_btfs,
+		       sizeof(env->used_btfs[0]) * env->used_btf_cnt);
+		env->prog->aux->used_btf_cnt = env->used_btf_cnt;
+	}
+	if (env->used_map_cnt || env->used_btf_cnt) {
+		/* program is valid. Convert pseudo bpf_ld_imm64 into generic
+		 * bpf_ld_imm64 instructions
+		 */
+		convert_pseudo_ld_imm64(env);
+	}
+
+	adjust_btf_func(env);
+
+err_release_maps:
+	if (!env->prog->aux->used_maps)
+		/* if we didn't copy map pointers into bpf_prog_info, release
+		 * them now. Otherwise free_used_maps() will release them.
+		 */
+		release_maps(env);
+	if (!env->prog->aux->used_btfs)
+		release_btfs(env);
+
+	/* extension progs temporarily inherit the attach_type of their targets
+	   for verification purposes, so set it back to zero before returning
+	 */
+	if (env->prog->type == BPF_PROG_TYPE_EXT)
+		env->prog->expected_attach_type = 0;
+
+	*prog = env->prog;
+err_unlock:
+	if (!is_priv)
+		mutex_unlock(&bpf_verifier_lock);
+	vfree(env->insn_aux_data);
+err_free_env:
+	kfree(env);
+	return ret;
+}