kernel/bpf/bpf_struct_ops.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2019 Facebook */
   3
   4 #include <linux/bpf.h>
   5 #include <linux/bpf_verifier.h>
   6 #include <linux/btf.h>
   7 #include <linux/filter.h>
   8 #include <linux/slab.h>
   9 #include <linux/numa.h>
  10 #include <linux/seq_file.h>
  11 #include <linux/refcount.h>
  12 #include <linux/mutex.h>
  13
  14 enum bpf_struct_ops_state {
  15         BPF_STRUCT_OPS_STATE_INIT,
  16         BPF_STRUCT_OPS_STATE_INUSE,
  17         BPF_STRUCT_OPS_STATE_TOBEFREE,
  18 };
  19
  20 #define BPF_STRUCT_OPS_COMMON_VALUE                     \
  21         refcount_t refcnt;                              \
  22         enum bpf_struct_ops_state state
  23
  24 struct bpf_struct_ops_value {
  25         BPF_STRUCT_OPS_COMMON_VALUE;
  26         char data[0] ____cacheline_aligned_in_smp;
  27 };
  28
  29 struct bpf_struct_ops_map {
  30         struct bpf_map map;
  31         const struct bpf_struct_ops *st_ops;
  32         /* protect map_update */
  33         struct mutex lock;
  34         /* progs has all the bpf_prog that is populated
  35          * to the func ptr of the kernel's struct
  36          * (in kvalue.data).
  37          */
  38         struct bpf_prog **progs;
  39         /* image is a page that has all the trampolines
  40          * that stores the func args before calling the bpf_prog.
  41          * A PAGE_SIZE "image" is enough to store all trampoline for
  42          * "progs[]".
  43          */
  44         void *image;
  45         /* uvalue->data stores the kernel struct
  46          * (e.g. tcp_congestion_ops) that is more useful
  47          * to userspace than the kvalue.  For example,
  48          * the bpf_prog's id is stored instead of the kernel
  49          * address of a func ptr.
  50          */
  51         struct bpf_struct_ops_value *uvalue;
  52         /* kvalue.data stores the actual kernel's struct
  53          * (e.g. tcp_congestion_ops) that will be
  54          * registered to the kernel subsystem.
  55          */
  56         struct bpf_struct_ops_value kvalue;
  57 };
  58
  59 #define VALUE_PREFIX "bpf_struct_ops_"
  60 #define VALUE_PREFIX_LEN (sizeof(VALUE_PREFIX) - 1)
  61
  62 /* bpf_struct_ops_##_name (e.g. bpf_struct_ops_tcp_congestion_ops) is
  63  * the map's value exposed to the userspace and its btf-type-id is
  64  * stored at the map->btf_vmlinux_value_type_id.
  65  *
  66  */
  67 #define BPF_STRUCT_OPS_TYPE(_name)                              \
  68 extern struct bpf_struct_ops bpf_##_name;                       \
  69                                                                 \
  70 struct bpf_struct_ops_##_name {                                         \
  71         BPF_STRUCT_OPS_COMMON_VALUE;                            \
  72         struct _name data ____cacheline_aligned_in_smp;         \
  73 };
  74 #include "bpf_struct_ops_types.h"
  75 #undef BPF_STRUCT_OPS_TYPE
  76
  77 enum {
  78 #define BPF_STRUCT_OPS_TYPE(_name) BPF_STRUCT_OPS_TYPE_##_name,
  79 #include "bpf_struct_ops_types.h"
  80 #undef BPF_STRUCT_OPS_TYPE
  81         __NR_BPF_STRUCT_OPS_TYPE,
  82 };
  83
  84 static struct bpf_struct_ops * const bpf_struct_ops[] = {
  85 #define BPF_STRUCT_OPS_TYPE(_name)                              \
  86         [BPF_STRUCT_OPS_TYPE_##_name] = &bpf_##_name,
  87 #include "bpf_struct_ops_types.h"
  88 #undef BPF_STRUCT_OPS_TYPE
  89 };
  90
  91 const struct bpf_verifier_ops bpf_struct_ops_verifier_ops = {
  92 };
  93
  94 const struct bpf_prog_ops bpf_struct_ops_prog_ops = {
  95 };
  96
  97 static const struct btf_type *module_type;
  98
  99 void bpf_struct_ops_init(struct btf *btf)
 100 {
 101         s32 type_id, value_id, module_id;
 102         const struct btf_member *member;
 103         struct bpf_struct_ops *st_ops;
 104         struct bpf_verifier_log log = {};
 105         const struct btf_type *t;
 106         char value_name[128];
 107         const char *mname;
 108         u32 i, j;
 109
 110         /* Ensure BTF type is emitted for "struct bpf_struct_ops_##_name" */
 111 #define BPF_STRUCT_OPS_TYPE(_name) BTF_TYPE_EMIT(struct bpf_struct_ops_##_name);
 112 #include "bpf_struct_ops_types.h"
 113 #undef BPF_STRUCT_OPS_TYPE
 114
 115         module_id = btf_find_by_name_kind(btf, "module", BTF_KIND_STRUCT);
 116         if (module_id < 0) {
 117                 pr_warn("Cannot find struct module in btf_vmlinux\n");
 118                 return;
 119         }
 120         module_type = btf_type_by_id(btf, module_id);
 121
 122         for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
 123                 st_ops = bpf_struct_ops[i];
 124
 125                 if (strlen(st_ops->name) + VALUE_PREFIX_LEN >=
 126                     sizeof(value_name)) {
 127                         pr_warn("struct_ops name %s is too long\n",
 128                                 st_ops->name);
 129                         continue;
 130                 }
 131                 sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
 132
 133                 value_id = btf_find_by_name_kind(btf, value_name,
 134                                                  BTF_KIND_STRUCT);
 135                 if (value_id < 0) {
 136                         pr_warn("Cannot find struct %s in btf_vmlinux\n",
 137                                 value_name);
 138                         continue;
 139                 }
 140
 141                 type_id = btf_find_by_name_kind(btf, st_ops->name,
 142                                                 BTF_KIND_STRUCT);
 143                 if (type_id < 0) {
 144                         pr_warn("Cannot find struct %s in btf_vmlinux\n",
 145                                 st_ops->name);
 146                         continue;
 147                 }
 148                 t = btf_type_by_id(btf, type_id);
 149                 if (btf_type_vlen(t) > BPF_STRUCT_OPS_MAX_NR_MEMBERS) {
 150                         pr_warn("Cannot support #%u members in struct %s\n",
 151                                 btf_type_vlen(t), st_ops->name);
 152                         continue;
 153                 }
 154
 155                 for_each_member(j, t, member) {
 156                         const struct btf_type *func_proto;
 157
 158                         mname = btf_name_by_offset(btf, member->name_off);
 159                         if (!*mname) {
 160                                 pr_warn("anon member in struct %s is not supported\n",
 161                                         st_ops->name);
 162                                 break;
 163                         }
 164
 165                         if (btf_member_bitfield_size(t, member)) {
 166                                 pr_warn("bit field member %s in struct %s is not supported\n",
 167                                         mname, st_ops->name);
 168                                 break;
 169                         }
 170
 171                         func_proto = btf_type_resolve_func_ptr(btf,
 172                                                                member->type,
 173                                                                NULL);
 174                         if (func_proto &&
 175                             btf_distill_func_proto(&log, btf,
 176                                                    func_proto, mname,
 177                                                    &st_ops->func_models[j])) {
 178                                 pr_warn("Error in parsing func ptr %s in struct %s\n",
 179                                         mname, st_ops->name);
 180                                 break;
 181                         }
 182                 }
 183
 184                 if (j == btf_type_vlen(t)) {
 185                         if (st_ops->init(btf)) {
 186                                 pr_warn("Error in init bpf_struct_ops %s\n",
 187                                         st_ops->name);
 188                         } else {
 189                                 st_ops->type_id = type_id;
 190                                 st_ops->type = t;
 191                                 st_ops->value_id = value_id;
 192                                 st_ops->value_type = btf_type_by_id(btf,
 193                                                                     value_id);
 194                         }
 195                 }
 196         }
 197 }
 198
 199 extern struct btf *btf_vmlinux;
 200
 201 static const struct bpf_struct_ops *
 202 bpf_struct_ops_find_value(u32 value_id)
 203 {
 204         unsigned int i;
 205
 206         if (!value_id || !btf_vmlinux)
 207                 return NULL;
 208
 209         for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
 210                 if (bpf_struct_ops[i]->value_id == value_id)
 211                         return bpf_struct_ops[i];
 212         }
 213
 214         return NULL;
 215 }
 216
 217 const struct bpf_struct_ops *bpf_struct_ops_find(u32 type_id)
 218 {
 219         unsigned int i;
 220
 221         if (!type_id || !btf_vmlinux)
 222                 return NULL;
 223
 224         for (i = 0; i < ARRAY_SIZE(bpf_struct_ops); i++) {
 225                 if (bpf_struct_ops[i]->type_id == type_id)
 226                         return bpf_struct_ops[i];
 227         }
 228
 229         return NULL;
 230 }
 231
 232 static int bpf_struct_ops_map_get_next_key(struct bpf_map *map, void *key,
 233                                            void *next_key)
 234 {
 235         if (key && *(u32 *)key == 0)
 236                 return -ENOENT;
 237
 238         *(u32 *)next_key = 0;
 239         return 0;
 240 }
 241
 242 int bpf_struct_ops_map_sys_lookup_elem(struct bpf_map *map, void *key,
 243                                        void *value)
 244 {
 245         struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
 246         struct bpf_struct_ops_value *uvalue, *kvalue;
 247         enum bpf_struct_ops_state state;
 248
 249         if (unlikely(*(u32 *)key != 0))
 250                 return -ENOENT;
 251
 252         kvalue = &st_map->kvalue;
 253         /* Pair with smp_store_release() during map_update */
 254         state = smp_load_acquire(&kvalue->state);
 255         if (state == BPF_STRUCT_OPS_STATE_INIT) {
 256                 memset(value, 0, map->value_size);
 257                 return 0;
 258         }
 259
 260         /* No lock is needed.  state and refcnt do not need
 261          * to be updated together under atomic context.
 262          */
 263         uvalue = (struct bpf_struct_ops_value *)value;
 264         memcpy(uvalue, st_map->uvalue, map->value_size);
 265         uvalue->state = state;
 266         refcount_set(&uvalue->refcnt, refcount_read(&kvalue->refcnt));
 267
 268         return 0;
 269 }
 270
 271 static void *bpf_struct_ops_map_lookup_elem(struct bpf_map *map, void *key)
 272 {
 273         return ERR_PTR(-EINVAL);
 274 }
 275
 276 static void bpf_struct_ops_map_put_progs(struct bpf_struct_ops_map *st_map)
 277 {
 278         const struct btf_type *t = st_map->st_ops->type;
 279         u32 i;
 280
 281         for (i = 0; i < btf_type_vlen(t); i++) {
 282                 if (st_map->progs[i]) {
 283                         bpf_prog_put(st_map->progs[i]);
 284                         st_map->progs[i] = NULL;
 285                 }
 286         }
 287 }
 288
 289 static int check_zero_holes(const struct btf_type *t, void *data)
 290 {
 291         const struct btf_member *member;
 292         u32 i, moff, msize, prev_mend = 0;
 293         const struct btf_type *mtype;
 294
 295         for_each_member(i, t, member) {
 296                 moff = btf_member_bit_offset(t, member) / 8;
 297                 if (moff > prev_mend &&
 298                     memchr_inv(data + prev_mend, 0, moff - prev_mend))
 299                         return -EINVAL;
 300
 301                 mtype = btf_type_by_id(btf_vmlinux, member->type);
 302                 mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
 303                                          NULL, NULL);
 304                 if (IS_ERR(mtype))
 305                         return PTR_ERR(mtype);
 306                 prev_mend = moff + msize;
 307         }
 308
 309         if (t->size > prev_mend &&
 310             memchr_inv(data + prev_mend, 0, t->size - prev_mend))
 311                 return -EINVAL;
 312
 313         return 0;
 314 }
 315
 316 static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
 317                                           void *value, u64 flags)
 318 {
 319         struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
 320         const struct bpf_struct_ops *st_ops = st_map->st_ops;
 321         struct bpf_struct_ops_value *uvalue, *kvalue;
 322         const struct btf_member *member;
 323         const struct btf_type *t = st_ops->type;
 324         void *udata, *kdata;
 325         int prog_fd, err = 0;
 326         void *image;
 327         u32 i;
 328
 329         if (flags)
 330                 return -EINVAL;
 331
 332         if (*(u32 *)key != 0)
 333                 return -E2BIG;
 334
 335         err = check_zero_holes(st_ops->value_type, value);
 336         if (err)
 337                 return err;
 338
 339         uvalue = (struct bpf_struct_ops_value *)value;
 340         err = check_zero_holes(t, uvalue->data);
 341         if (err)
 342                 return err;
 343
 344         if (uvalue->state || refcount_read(&uvalue->refcnt))
 345                 return -EINVAL;
 346
 347         uvalue = (struct bpf_struct_ops_value *)st_map->uvalue;
 348         kvalue = (struct bpf_struct_ops_value *)&st_map->kvalue;
 349
 350         mutex_lock(&st_map->lock);
 351
 352         if (kvalue->state != BPF_STRUCT_OPS_STATE_INIT) {
 353                 err = -EBUSY;
 354                 goto unlock;
 355         }
 356
 357         memcpy(uvalue, value, map->value_size);
 358
 359         udata = &uvalue->data;
 360         kdata = &kvalue->data;
 361         image = st_map->image;
 362
 363         for_each_member(i, t, member) {
 364                 const struct btf_type *mtype, *ptype;
 365                 struct bpf_prog *prog;
 366                 u32 moff;
 367
 368                 moff = btf_member_bit_offset(t, member) / 8;
 369                 ptype = btf_type_resolve_ptr(btf_vmlinux, member->type, NULL);
 370                 if (ptype == module_type) {
 371                         if (*(void **)(udata + moff))
 372                                 goto reset_unlock;
 373                         *(void **)(kdata + moff) = BPF_MODULE_OWNER;
 374                         continue;
 375                 }
 376
 377                 err = st_ops->init_member(t, member, kdata, udata);
 378                 if (err < 0)
 379                         goto reset_unlock;
 380
 381                 /* The ->init_member() has handled this member */
 382                 if (err > 0)
 383                         continue;
 384
 385                 /* If st_ops->init_member does not handle it,
 386                  * we will only handle func ptrs and zero-ed members
 387                  * here.  Reject everything else.
 388                  */
 389
 390                 /* All non func ptr member must be 0 */
 391                 if (!ptype || !btf_type_is_func_proto(ptype)) {
 392                         u32 msize;
 393
 394                         mtype = btf_type_by_id(btf_vmlinux, member->type);
 395                         mtype = btf_resolve_size(btf_vmlinux, mtype, &msize,
 396                                                  NULL, NULL);
 397                         if (IS_ERR(mtype)) {
 398                                 err = PTR_ERR(mtype);
 399                                 goto reset_unlock;
 400                         }
 401
 402                         if (memchr_inv(udata + moff, 0, msize)) {
 403                                 err = -EINVAL;
 404                                 goto reset_unlock;
 405                         }
 406
 407                         continue;
 408                 }
 409
 410                 prog_fd = (int)(*(unsigned long *)(udata + moff));
 411                 /* Similar check as the attr->attach_prog_fd */
 412                 if (!prog_fd)
 413                         continue;
 414
 415                 prog = bpf_prog_get(prog_fd);
 416                 if (IS_ERR(prog)) {
 417                         err = PTR_ERR(prog);
 418                         goto reset_unlock;
 419                 }
 420                 st_map->progs[i] = prog;
 421
 422                 if (prog->type != BPF_PROG_TYPE_STRUCT_OPS ||
 423                     prog->aux->attach_btf_id != st_ops->type_id ||
 424                     prog->expected_attach_type != i) {
 425                         err = -EINVAL;
 426                         goto reset_unlock;
 427                 }
 428
 429                 err = arch_prepare_bpf_trampoline(image,
 430                                                   st_map->image + PAGE_SIZE,
 431                                                   &st_ops->func_models[i], 0,
 432                                                   &prog, 1, NULL, 0, NULL);
 433                 if (err < 0)
 434                         goto reset_unlock;
 435
 436                 *(void **)(kdata + moff) = image;
 437                 image += err;
 438
 439                 /* put prog_id to udata */
 440                 *(unsigned long *)(udata + moff) = prog->aux->id;
 441         }
 442
 443         refcount_set(&kvalue->refcnt, 1);
 444         bpf_map_inc(map);
 445
 446         set_memory_ro((long)st_map->image, 1);
 447         set_memory_x((long)st_map->image, 1);
 448         err = st_ops->reg(kdata);
 449         if (likely(!err)) {
 450                 /* Pair with smp_load_acquire() during lookup_elem().
 451                  * It ensures the above udata updates (e.g. prog->aux->id)
 452                  * can be seen once BPF_STRUCT_OPS_STATE_INUSE is set.
 453                  */
 454                 smp_store_release(&kvalue->state, BPF_STRUCT_OPS_STATE_INUSE);
 455                 goto unlock;
 456         }
 457
 458         /* Error during st_ops->reg().  It is very unlikely since
 459          * the above init_member() should have caught it earlier
 460          * before reg().  The only possibility is if there was a race
 461          * in registering the struct_ops (under the same name) to
 462          * a sub-system through different struct_ops's maps.
 463          */
 464         set_memory_nx((long)st_map->image, 1);
 465         set_memory_rw((long)st_map->image, 1);
 466         bpf_map_put(map);
 467
 468 reset_unlock:
 469         bpf_struct_ops_map_put_progs(st_map);
 470         memset(uvalue, 0, map->value_size);
 471         memset(kvalue, 0, map->value_size);
 472 unlock:
 473         mutex_unlock(&st_map->lock);
 474         return err;
 475 }
 476
 477 static int bpf_struct_ops_map_delete_elem(struct bpf_map *map, void *key)
 478 {
 479         enum bpf_struct_ops_state prev_state;
 480         struct bpf_struct_ops_map *st_map;
 481
 482         st_map = (struct bpf_struct_ops_map *)map;
 483         prev_state = cmpxchg(&st_map->kvalue.state,
 484                              BPF_STRUCT_OPS_STATE_INUSE,
 485                              BPF_STRUCT_OPS_STATE_TOBEFREE);
 486         if (prev_state == BPF_STRUCT_OPS_STATE_INUSE) {
 487                 st_map->st_ops->unreg(&st_map->kvalue.data);
 488                 if (refcount_dec_and_test(&st_map->kvalue.refcnt))
 489                         bpf_map_put(map);
 490         }
 491
 492         return 0;
 493 }
 494
 495 static void bpf_struct_ops_map_seq_show_elem(struct bpf_map *map, void *key,
 496                                              struct seq_file *m)
 497 {
 498         void *value;
 499         int err;
 500
 501         value = kmalloc(map->value_size, GFP_USER | __GFP_NOWARN);
 502         if (!value)
 503                 return;
 504
 505         err = bpf_struct_ops_map_sys_lookup_elem(map, key, value);
 506         if (!err) {
 507                 btf_type_seq_show(btf_vmlinux, map->btf_vmlinux_value_type_id,
 508                                   value, m);
 509                 seq_puts(m, "\n");
 510         }
 511
 512         kfree(value);
 513 }
 514
 515 static void bpf_struct_ops_map_free(struct bpf_map *map)
 516 {
 517         struct bpf_struct_ops_map *st_map = (struct bpf_struct_ops_map *)map;
 518
 519         if (st_map->progs)
 520                 bpf_struct_ops_map_put_progs(st_map);
 521         bpf_map_area_free(st_map->progs);
 522         bpf_jit_free_exec(st_map->image);
 523         bpf_map_area_free(st_map->uvalue);
 524         bpf_map_area_free(st_map);
 525 }
 526
 527 static int bpf_struct_ops_map_alloc_check(union bpf_attr *attr)
 528 {
 529         if (attr->key_size != sizeof(unsigned int) || attr->max_entries != 1 ||
 530             attr->map_flags || !attr->btf_vmlinux_value_type_id)
 531                 return -EINVAL;
 532         return 0;
 533 }
 534
 535 static struct bpf_map *bpf_struct_ops_map_alloc(union bpf_attr *attr)
 536 {
 537         const struct bpf_struct_ops *st_ops;
 538         size_t map_total_size, st_map_size;
 539         struct bpf_struct_ops_map *st_map;
 540         const struct btf_type *t, *vt;
 541         struct bpf_map_memory mem;
 542         struct bpf_map *map;
 543         int err;
 544
 545         if (!capable(CAP_SYS_ADMIN))
 546                 return ERR_PTR(-EPERM);
 547
 548         st_ops = bpf_struct_ops_find_value(attr->btf_vmlinux_value_type_id);
 549         if (!st_ops)
 550                 return ERR_PTR(-ENOTSUPP);
 551
 552         vt = st_ops->value_type;
 553         if (attr->value_size != vt->size)
 554                 return ERR_PTR(-EINVAL);
 555
 556         t = st_ops->type;
 557
 558         st_map_size = sizeof(*st_map) +
 559                 /* kvalue stores the
 560                  * struct bpf_struct_ops_tcp_congestions_ops
 561                  */
 562                 (vt->size - sizeof(struct bpf_struct_ops_value));
 563         map_total_size = st_map_size +
 564                 /* uvalue */
 565                 sizeof(vt->size) +
 566                 /* struct bpf_progs **progs */
 567                  btf_type_vlen(t) * sizeof(struct bpf_prog *);
 568         err = bpf_map_charge_init(&mem, map_total_size);
 569         if (err < 0)
 570                 return ERR_PTR(err);
 571
 572         st_map = bpf_map_area_alloc(st_map_size, NUMA_NO_NODE);
 573         if (!st_map) {
 574                 bpf_map_charge_finish(&mem);
 575                 return ERR_PTR(-ENOMEM);
 576         }
 577         st_map->st_ops = st_ops;
 578         map = &st_map->map;
 579
 580         st_map->uvalue = bpf_map_area_alloc(vt->size, NUMA_NO_NODE);
 581         st_map->progs =
 582                 bpf_map_area_alloc(btf_type_vlen(t) * sizeof(struct bpf_prog *),
 583                                    NUMA_NO_NODE);
 584         st_map->image = bpf_jit_alloc_exec(PAGE_SIZE);
 585         if (!st_map->uvalue || !st_map->progs || !st_map->image) {
 586                 bpf_struct_ops_map_free(map);
 587                 bpf_map_charge_finish(&mem);
 588                 return ERR_PTR(-ENOMEM);
 589         }
 590
 591         mutex_init(&st_map->lock);
 592         set_vm_flush_reset_perms(st_map->image);
 593         bpf_map_init_from_attr(map, attr);
 594         bpf_map_charge_move(&map->memory, &mem);
 595
 596         return map;
 597 }
 598
 599 const struct bpf_map_ops bpf_struct_ops_map_ops = {
 600         .map_alloc_check = bpf_struct_ops_map_alloc_check,
 601         .map_alloc = bpf_struct_ops_map_alloc,
 602         .map_free = bpf_struct_ops_map_free,
 603         .map_get_next_key = bpf_struct_ops_map_get_next_key,
 604         .map_lookup_elem = bpf_struct_ops_map_lookup_elem,
 605         .map_delete_elem = bpf_struct_ops_map_delete_elem,
 606         .map_update_elem = bpf_struct_ops_map_update_elem,
 607         .map_seq_show_elem = bpf_struct_ops_map_seq_show_elem,
 608 };
 609
 610 /* "const void *" because some subsystem is
 611  * passing a const (e.g. const struct tcp_congestion_ops *)
 612  */
 613 bool bpf_struct_ops_get(const void *kdata)
 614 {
 615         struct bpf_struct_ops_value *kvalue;
 616
 617         kvalue = container_of(kdata, struct bpf_struct_ops_value, data);
 618
 619         return refcount_inc_not_zero(&kvalue->refcnt);
 620 }
 621
 622 void bpf_struct_ops_put(const void *kdata)
 623 {
 624         struct bpf_struct_ops_value *kvalue;
 625
 626         kvalue = container_of(kdata, struct bpf_struct_ops_value, data);
 627         if (refcount_dec_and_test(&kvalue->refcnt)) {
 628                 struct bpf_struct_ops_map *st_map;
 629
 630                 st_map = container_of(kvalue, struct bpf_struct_ops_map,
 631                                       kvalue);
 632                 bpf_map_put(&st_map->map);
 633         }
 634 }