1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (c) 2016 Facebook 3 */ 4 #include <linux/bpf.h> 5 #include <linux/jhash.h> 6 #include <linux/filter.h> 7 #include <linux/kernel.h> 8 #include <linux/stacktrace.h> 9 #include <linux/perf_event.h> 10 #include <linux/btf_ids.h> 11 #include <linux/buildid.h> 12 #include "percpu_freelist.h" 13 #include "mmap_unlock_work.h" 14 15 #define STACK_CREATE_FLAG_MASK \ 16 (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY | \ 17 BPF_F_STACK_BUILD_ID) 18 19 struct stack_map_bucket { 20 struct pcpu_freelist_node fnode; 21 u32 hash; 22 u32 nr; 23 u64 data[]; 24 }; 25 26 struct bpf_stack_map { 27 struct bpf_map map; 28 void *elems; 29 struct pcpu_freelist freelist; 30 u32 n_buckets; 31 struct stack_map_bucket *buckets[]; 32 }; 33 34 static inline bool stack_map_use_build_id(struct bpf_map *map) 35 { 36 return (map->map_flags & BPF_F_STACK_BUILD_ID); 37 } 38 39 static inline int stack_map_data_size(struct bpf_map *map) 40 { 41 return stack_map_use_build_id(map) ? 42 sizeof(struct bpf_stack_build_id) : sizeof(u64); 43 } 44 45 static int prealloc_elems_and_freelist(struct bpf_stack_map *smap) 46 { 47 u64 elem_size = sizeof(struct stack_map_bucket) + 48 (u64)smap->map.value_size; 49 int err; 50 51 smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries, 52 smap->map.numa_node); 53 if (!smap->elems) 54 return -ENOMEM; 55 56 err = pcpu_freelist_init(&smap->freelist); 57 if (err) 58 goto free_elems; 59 60 pcpu_freelist_populate(&smap->freelist, smap->elems, elem_size, 61 smap->map.max_entries); 62 return 0; 63 64 free_elems: 65 bpf_map_area_free(smap->elems); 66 return err; 67 } 68 69 /* Called from syscall */ 70 static struct bpf_map *stack_map_alloc(union bpf_attr *attr) 71 { 72 u32 value_size = attr->value_size; 73 struct bpf_stack_map *smap; 74 u64 cost, n_buckets; 75 int err; 76 77 if (!bpf_capable()) 78 return ERR_PTR(-EPERM); 79 80 if (attr->map_flags & ~STACK_CREATE_FLAG_MASK) 81 return ERR_PTR(-EINVAL); 82 83 /* check sanity of attributes */ 84 if (attr->max_entries == 0 || attr->key_size != 4 || 85 value_size < 8 || value_size % 8) 86 return ERR_PTR(-EINVAL); 87 88 BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64)); 89 if (attr->map_flags & BPF_F_STACK_BUILD_ID) { 90 if (value_size % sizeof(struct bpf_stack_build_id) || 91 value_size / sizeof(struct bpf_stack_build_id) 92 > sysctl_perf_event_max_stack) 93 return ERR_PTR(-EINVAL); 94 } else if (value_size / 8 > sysctl_perf_event_max_stack) 95 return ERR_PTR(-EINVAL); 96 97 /* hash table size must be power of 2 */ 98 n_buckets = roundup_pow_of_two(attr->max_entries); 99 if (!n_buckets) 100 return ERR_PTR(-E2BIG); 101 102 cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap); 103 cost += n_buckets * (value_size + sizeof(struct stack_map_bucket)); 104 smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr)); 105 if (!smap) 106 return ERR_PTR(-ENOMEM); 107 108 bpf_map_init_from_attr(&smap->map, attr); 109 smap->map.value_size = value_size; 110 smap->n_buckets = n_buckets; 111 112 err = get_callchain_buffers(sysctl_perf_event_max_stack); 113 if (err) 114 goto free_smap; 115 116 err = prealloc_elems_and_freelist(smap); 117 if (err) 118 goto put_buffers; 119 120 return &smap->map; 121 122 put_buffers: 123 put_callchain_buffers(); 124 free_smap: 125 bpf_map_area_free(smap); 126 return ERR_PTR(err); 127 } 128 129 static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, 130 u64 *ips, u32 trace_nr, bool user) 131 { 132 int i; 133 struct mmap_unlock_irq_work *work = NULL; 134 bool irq_work_busy = bpf_mmap_unlock_get_irq_work(&work); 135 struct vm_area_struct *vma, *prev_vma = NULL; 136 const char *prev_build_id; 137 138 /* If the irq_work is in use, fall back to report ips. Same 139 * fallback is used for kernel stack (!user) on a stackmap with 140 * build_id. 141 */ 142 if (!user || !current || !current->mm || irq_work_busy || 143 !mmap_read_trylock(current->mm)) { 144 /* cannot access current->mm, fall back to ips */ 145 for (i = 0; i < trace_nr; i++) { 146 id_offs[i].status = BPF_STACK_BUILD_ID_IP; 147 id_offs[i].ip = ips[i]; 148 memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); 149 } 150 return; 151 } 152 153 for (i = 0; i < trace_nr; i++) { 154 if (range_in_vma(prev_vma, ips[i], ips[i])) { 155 vma = prev_vma; 156 memcpy(id_offs[i].build_id, prev_build_id, 157 BUILD_ID_SIZE_MAX); 158 goto build_id_valid; 159 } 160 vma = find_vma(current->mm, ips[i]); 161 if (!vma || build_id_parse(vma, id_offs[i].build_id, NULL)) { 162 /* per entry fall back to ips */ 163 id_offs[i].status = BPF_STACK_BUILD_ID_IP; 164 id_offs[i].ip = ips[i]; 165 memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); 166 continue; 167 } 168 build_id_valid: 169 id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i] 170 - vma->vm_start; 171 id_offs[i].status = BPF_STACK_BUILD_ID_VALID; 172 prev_vma = vma; 173 prev_build_id = id_offs[i].build_id; 174 } 175 bpf_mmap_unlock_mm(work, current->mm); 176 } 177 178 static struct perf_callchain_entry * 179 get_callchain_entry_for_task(struct task_struct *task, u32 init_nr) 180 { 181 #ifdef CONFIG_STACKTRACE 182 struct perf_callchain_entry *entry; 183 int rctx; 184 185 entry = get_callchain_entry(&rctx); 186 187 if (!entry) 188 return NULL; 189 190 entry->nr = init_nr + 191 stack_trace_save_tsk(task, (unsigned long *)(entry->ip + init_nr), 192 sysctl_perf_event_max_stack - init_nr, 0); 193 194 /* stack_trace_save_tsk() works on unsigned long array, while 195 * perf_callchain_entry uses u64 array. For 32-bit systems, it is 196 * necessary to fix this mismatch. 197 */ 198 if (__BITS_PER_LONG != 64) { 199 unsigned long *from = (unsigned long *) entry->ip; 200 u64 *to = entry->ip; 201 int i; 202 203 /* copy data from the end to avoid using extra buffer */ 204 for (i = entry->nr - 1; i >= (int)init_nr; i--) 205 to[i] = (u64)(from[i]); 206 } 207 208 put_callchain_entry(rctx); 209 210 return entry; 211 #else /* CONFIG_STACKTRACE */ 212 return NULL; 213 #endif 214 } 215 216 static long __bpf_get_stackid(struct bpf_map *map, 217 struct perf_callchain_entry *trace, u64 flags) 218 { 219 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 220 struct stack_map_bucket *bucket, *new_bucket, *old_bucket; 221 u32 max_depth = map->value_size / stack_map_data_size(map); 222 /* stack_map_alloc() checks that max_depth <= sysctl_perf_event_max_stack */ 223 u32 init_nr = sysctl_perf_event_max_stack - max_depth; 224 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 225 u32 hash, id, trace_nr, trace_len; 226 bool user = flags & BPF_F_USER_STACK; 227 u64 *ips; 228 bool hash_matches; 229 230 /* get_perf_callchain() guarantees that trace->nr >= init_nr 231 * and trace-nr <= sysctl_perf_event_max_stack, so trace_nr <= max_depth 232 */ 233 trace_nr = trace->nr - init_nr; 234 235 if (trace_nr <= skip) 236 /* skipping more than usable stack trace */ 237 return -EFAULT; 238 239 trace_nr -= skip; 240 trace_len = trace_nr * sizeof(u64); 241 ips = trace->ip + skip + init_nr; 242 hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0); 243 id = hash & (smap->n_buckets - 1); 244 bucket = READ_ONCE(smap->buckets[id]); 245 246 hash_matches = bucket && bucket->hash == hash; 247 /* fast cmp */ 248 if (hash_matches && flags & BPF_F_FAST_STACK_CMP) 249 return id; 250 251 if (stack_map_use_build_id(map)) { 252 /* for build_id+offset, pop a bucket before slow cmp */ 253 new_bucket = (struct stack_map_bucket *) 254 pcpu_freelist_pop(&smap->freelist); 255 if (unlikely(!new_bucket)) 256 return -ENOMEM; 257 new_bucket->nr = trace_nr; 258 stack_map_get_build_id_offset( 259 (struct bpf_stack_build_id *)new_bucket->data, 260 ips, trace_nr, user); 261 trace_len = trace_nr * sizeof(struct bpf_stack_build_id); 262 if (hash_matches && bucket->nr == trace_nr && 263 memcmp(bucket->data, new_bucket->data, trace_len) == 0) { 264 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); 265 return id; 266 } 267 if (bucket && !(flags & BPF_F_REUSE_STACKID)) { 268 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); 269 return -EEXIST; 270 } 271 } else { 272 if (hash_matches && bucket->nr == trace_nr && 273 memcmp(bucket->data, ips, trace_len) == 0) 274 return id; 275 if (bucket && !(flags & BPF_F_REUSE_STACKID)) 276 return -EEXIST; 277 278 new_bucket = (struct stack_map_bucket *) 279 pcpu_freelist_pop(&smap->freelist); 280 if (unlikely(!new_bucket)) 281 return -ENOMEM; 282 memcpy(new_bucket->data, ips, trace_len); 283 } 284 285 new_bucket->hash = hash; 286 new_bucket->nr = trace_nr; 287 288 old_bucket = xchg(&smap->buckets[id], new_bucket); 289 if (old_bucket) 290 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 291 return id; 292 } 293 294 BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, 295 u64, flags) 296 { 297 u32 max_depth = map->value_size / stack_map_data_size(map); 298 /* stack_map_alloc() checks that max_depth <= sysctl_perf_event_max_stack */ 299 u32 init_nr = sysctl_perf_event_max_stack - max_depth; 300 bool user = flags & BPF_F_USER_STACK; 301 struct perf_callchain_entry *trace; 302 bool kernel = !user; 303 304 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 305 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) 306 return -EINVAL; 307 308 trace = get_perf_callchain(regs, init_nr, kernel, user, 309 sysctl_perf_event_max_stack, false, false); 310 311 if (unlikely(!trace)) 312 /* couldn't fetch the stack trace */ 313 return -EFAULT; 314 315 return __bpf_get_stackid(map, trace, flags); 316 } 317 318 const struct bpf_func_proto bpf_get_stackid_proto = { 319 .func = bpf_get_stackid, 320 .gpl_only = true, 321 .ret_type = RET_INTEGER, 322 .arg1_type = ARG_PTR_TO_CTX, 323 .arg2_type = ARG_CONST_MAP_PTR, 324 .arg3_type = ARG_ANYTHING, 325 }; 326 327 static __u64 count_kernel_ip(struct perf_callchain_entry *trace) 328 { 329 __u64 nr_kernel = 0; 330 331 while (nr_kernel < trace->nr) { 332 if (trace->ip[nr_kernel] == PERF_CONTEXT_USER) 333 break; 334 nr_kernel++; 335 } 336 return nr_kernel; 337 } 338 339 BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, 340 struct bpf_map *, map, u64, flags) 341 { 342 struct perf_event *event = ctx->event; 343 struct perf_callchain_entry *trace; 344 bool kernel, user; 345 __u64 nr_kernel; 346 int ret; 347 348 /* perf_sample_data doesn't have callchain, use bpf_get_stackid */ 349 if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) 350 return bpf_get_stackid((unsigned long)(ctx->regs), 351 (unsigned long) map, flags, 0, 0); 352 353 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 354 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) 355 return -EINVAL; 356 357 user = flags & BPF_F_USER_STACK; 358 kernel = !user; 359 360 trace = ctx->data->callchain; 361 if (unlikely(!trace)) 362 return -EFAULT; 363 364 nr_kernel = count_kernel_ip(trace); 365 366 if (kernel) { 367 __u64 nr = trace->nr; 368 369 trace->nr = nr_kernel; 370 ret = __bpf_get_stackid(map, trace, flags); 371 372 /* restore nr */ 373 trace->nr = nr; 374 } else { /* user */ 375 u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 376 377 skip += nr_kernel; 378 if (skip > BPF_F_SKIP_FIELD_MASK) 379 return -EFAULT; 380 381 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; 382 ret = __bpf_get_stackid(map, trace, flags); 383 } 384 return ret; 385 } 386 387 const struct bpf_func_proto bpf_get_stackid_proto_pe = { 388 .func = bpf_get_stackid_pe, 389 .gpl_only = false, 390 .ret_type = RET_INTEGER, 391 .arg1_type = ARG_PTR_TO_CTX, 392 .arg2_type = ARG_CONST_MAP_PTR, 393 .arg3_type = ARG_ANYTHING, 394 }; 395 396 static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, 397 struct perf_callchain_entry *trace_in, 398 void *buf, u32 size, u64 flags) 399 { 400 u32 init_nr, trace_nr, copy_len, elem_size, num_elem; 401 bool user_build_id = flags & BPF_F_USER_BUILD_ID; 402 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 403 bool user = flags & BPF_F_USER_STACK; 404 struct perf_callchain_entry *trace; 405 bool kernel = !user; 406 int err = -EINVAL; 407 u64 *ips; 408 409 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 410 BPF_F_USER_BUILD_ID))) 411 goto clear; 412 if (kernel && user_build_id) 413 goto clear; 414 415 elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id) 416 : sizeof(u64); 417 if (unlikely(size % elem_size)) 418 goto clear; 419 420 /* cannot get valid user stack for task without user_mode regs */ 421 if (task && user && !user_mode(regs)) 422 goto err_fault; 423 424 num_elem = size / elem_size; 425 if (sysctl_perf_event_max_stack < num_elem) 426 init_nr = 0; 427 else 428 init_nr = sysctl_perf_event_max_stack - num_elem; 429 430 if (trace_in) 431 trace = trace_in; 432 else if (kernel && task) 433 trace = get_callchain_entry_for_task(task, init_nr); 434 else 435 trace = get_perf_callchain(regs, init_nr, kernel, user, 436 sysctl_perf_event_max_stack, 437 false, false); 438 if (unlikely(!trace)) 439 goto err_fault; 440 441 trace_nr = trace->nr - init_nr; 442 if (trace_nr < skip) 443 goto err_fault; 444 445 trace_nr -= skip; 446 trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem; 447 copy_len = trace_nr * elem_size; 448 ips = trace->ip + skip + init_nr; 449 if (user && user_build_id) 450 stack_map_get_build_id_offset(buf, ips, trace_nr, user); 451 else 452 memcpy(buf, ips, copy_len); 453 454 if (size > copy_len) 455 memset(buf + copy_len, 0, size - copy_len); 456 return copy_len; 457 458 err_fault: 459 err = -EFAULT; 460 clear: 461 memset(buf, 0, size); 462 return err; 463 } 464 465 BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size, 466 u64, flags) 467 { 468 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); 469 } 470 471 const struct bpf_func_proto bpf_get_stack_proto = { 472 .func = bpf_get_stack, 473 .gpl_only = true, 474 .ret_type = RET_INTEGER, 475 .arg1_type = ARG_PTR_TO_CTX, 476 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 477 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 478 .arg4_type = ARG_ANYTHING, 479 }; 480 481 BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf, 482 u32, size, u64, flags) 483 { 484 struct pt_regs *regs; 485 long res = -EINVAL; 486 487 if (!try_get_task_stack(task)) 488 return -EFAULT; 489 490 regs = task_pt_regs(task); 491 if (regs) 492 res = __bpf_get_stack(regs, task, NULL, buf, size, flags); 493 put_task_stack(task); 494 495 return res; 496 } 497 498 const struct bpf_func_proto bpf_get_task_stack_proto = { 499 .func = bpf_get_task_stack, 500 .gpl_only = false, 501 .ret_type = RET_INTEGER, 502 .arg1_type = ARG_PTR_TO_BTF_ID, 503 .arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], 504 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 505 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 506 .arg4_type = ARG_ANYTHING, 507 }; 508 509 BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, 510 void *, buf, u32, size, u64, flags) 511 { 512 struct pt_regs *regs = (struct pt_regs *)(ctx->regs); 513 struct perf_event *event = ctx->event; 514 struct perf_callchain_entry *trace; 515 bool kernel, user; 516 int err = -EINVAL; 517 __u64 nr_kernel; 518 519 if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) 520 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); 521 522 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 523 BPF_F_USER_BUILD_ID))) 524 goto clear; 525 526 user = flags & BPF_F_USER_STACK; 527 kernel = !user; 528 529 err = -EFAULT; 530 trace = ctx->data->callchain; 531 if (unlikely(!trace)) 532 goto clear; 533 534 nr_kernel = count_kernel_ip(trace); 535 536 if (kernel) { 537 __u64 nr = trace->nr; 538 539 trace->nr = nr_kernel; 540 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); 541 542 /* restore nr */ 543 trace->nr = nr; 544 } else { /* user */ 545 u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 546 547 skip += nr_kernel; 548 if (skip > BPF_F_SKIP_FIELD_MASK) 549 goto clear; 550 551 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; 552 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); 553 } 554 return err; 555 556 clear: 557 memset(buf, 0, size); 558 return err; 559 560 } 561 562 const struct bpf_func_proto bpf_get_stack_proto_pe = { 563 .func = bpf_get_stack_pe, 564 .gpl_only = true, 565 .ret_type = RET_INTEGER, 566 .arg1_type = ARG_PTR_TO_CTX, 567 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 568 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 569 .arg4_type = ARG_ANYTHING, 570 }; 571 572 /* Called from eBPF program */ 573 static void *stack_map_lookup_elem(struct bpf_map *map, void *key) 574 { 575 return ERR_PTR(-EOPNOTSUPP); 576 } 577 578 /* Called from syscall */ 579 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) 580 { 581 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 582 struct stack_map_bucket *bucket, *old_bucket; 583 u32 id = *(u32 *)key, trace_len; 584 585 if (unlikely(id >= smap->n_buckets)) 586 return -ENOENT; 587 588 bucket = xchg(&smap->buckets[id], NULL); 589 if (!bucket) 590 return -ENOENT; 591 592 trace_len = bucket->nr * stack_map_data_size(map); 593 memcpy(value, bucket->data, trace_len); 594 memset(value + trace_len, 0, map->value_size - trace_len); 595 596 old_bucket = xchg(&smap->buckets[id], bucket); 597 if (old_bucket) 598 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 599 return 0; 600 } 601 602 static int stack_map_get_next_key(struct bpf_map *map, void *key, 603 void *next_key) 604 { 605 struct bpf_stack_map *smap = container_of(map, 606 struct bpf_stack_map, map); 607 u32 id; 608 609 WARN_ON_ONCE(!rcu_read_lock_held()); 610 611 if (!key) { 612 id = 0; 613 } else { 614 id = *(u32 *)key; 615 if (id >= smap->n_buckets || !smap->buckets[id]) 616 id = 0; 617 else 618 id++; 619 } 620 621 while (id < smap->n_buckets && !smap->buckets[id]) 622 id++; 623 624 if (id >= smap->n_buckets) 625 return -ENOENT; 626 627 *(u32 *)next_key = id; 628 return 0; 629 } 630 631 static int stack_map_update_elem(struct bpf_map *map, void *key, void *value, 632 u64 map_flags) 633 { 634 return -EINVAL; 635 } 636 637 /* Called from syscall or from eBPF program */ 638 static int stack_map_delete_elem(struct bpf_map *map, void *key) 639 { 640 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 641 struct stack_map_bucket *old_bucket; 642 u32 id = *(u32 *)key; 643 644 if (unlikely(id >= smap->n_buckets)) 645 return -E2BIG; 646 647 old_bucket = xchg(&smap->buckets[id], NULL); 648 if (old_bucket) { 649 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 650 return 0; 651 } else { 652 return -ENOENT; 653 } 654 } 655 656 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */ 657 static void stack_map_free(struct bpf_map *map) 658 { 659 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 660 661 bpf_map_area_free(smap->elems); 662 pcpu_freelist_destroy(&smap->freelist); 663 bpf_map_area_free(smap); 664 put_callchain_buffers(); 665 } 666 667 static int stack_trace_map_btf_id; 668 const struct bpf_map_ops stack_trace_map_ops = { 669 .map_meta_equal = bpf_map_meta_equal, 670 .map_alloc = stack_map_alloc, 671 .map_free = stack_map_free, 672 .map_get_next_key = stack_map_get_next_key, 673 .map_lookup_elem = stack_map_lookup_elem, 674 .map_update_elem = stack_map_update_elem, 675 .map_delete_elem = stack_map_delete_elem, 676 .map_check_btf = map_check_no_btf, 677 .map_btf_name = "bpf_stack_map", 678 .map_btf_id = &stack_trace_map_btf_id, 679 }; 680