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