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 (attr->map_flags & ~STACK_CREATE_FLAG_MASK) 78 return ERR_PTR(-EINVAL); 79 80 /* check sanity of attributes */ 81 if (attr->max_entries == 0 || attr->key_size != 4 || 82 value_size < 8 || value_size % 8) 83 return ERR_PTR(-EINVAL); 84 85 BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64)); 86 if (attr->map_flags & BPF_F_STACK_BUILD_ID) { 87 if (value_size % sizeof(struct bpf_stack_build_id) || 88 value_size / sizeof(struct bpf_stack_build_id) 89 > sysctl_perf_event_max_stack) 90 return ERR_PTR(-EINVAL); 91 } else if (value_size / 8 > sysctl_perf_event_max_stack) 92 return ERR_PTR(-EINVAL); 93 94 /* hash table size must be power of 2 */ 95 n_buckets = roundup_pow_of_two(attr->max_entries); 96 if (!n_buckets) 97 return ERR_PTR(-E2BIG); 98 99 cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap); 100 smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr)); 101 if (!smap) 102 return ERR_PTR(-ENOMEM); 103 104 bpf_map_init_from_attr(&smap->map, attr); 105 smap->n_buckets = n_buckets; 106 107 err = get_callchain_buffers(sysctl_perf_event_max_stack); 108 if (err) 109 goto free_smap; 110 111 err = prealloc_elems_and_freelist(smap); 112 if (err) 113 goto put_buffers; 114 115 return &smap->map; 116 117 put_buffers: 118 put_callchain_buffers(); 119 free_smap: 120 bpf_map_area_free(smap); 121 return ERR_PTR(err); 122 } 123 124 static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs, 125 u64 *ips, u32 trace_nr, bool user) 126 { 127 int i; 128 struct mmap_unlock_irq_work *work = NULL; 129 bool irq_work_busy = bpf_mmap_unlock_get_irq_work(&work); 130 struct vm_area_struct *vma, *prev_vma = NULL; 131 const char *prev_build_id; 132 133 /* If the irq_work is in use, fall back to report ips. Same 134 * fallback is used for kernel stack (!user) on a stackmap with 135 * build_id. 136 */ 137 if (!user || !current || !current->mm || irq_work_busy || 138 !mmap_read_trylock(current->mm)) { 139 /* cannot access current->mm, fall back to ips */ 140 for (i = 0; i < trace_nr; i++) { 141 id_offs[i].status = BPF_STACK_BUILD_ID_IP; 142 id_offs[i].ip = ips[i]; 143 memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); 144 } 145 return; 146 } 147 148 for (i = 0; i < trace_nr; i++) { 149 if (range_in_vma(prev_vma, ips[i], ips[i])) { 150 vma = prev_vma; 151 memcpy(id_offs[i].build_id, prev_build_id, 152 BUILD_ID_SIZE_MAX); 153 goto build_id_valid; 154 } 155 vma = find_vma(current->mm, ips[i]); 156 if (!vma || build_id_parse(vma, id_offs[i].build_id, NULL)) { 157 /* per entry fall back to ips */ 158 id_offs[i].status = BPF_STACK_BUILD_ID_IP; 159 id_offs[i].ip = ips[i]; 160 memset(id_offs[i].build_id, 0, BUILD_ID_SIZE_MAX); 161 continue; 162 } 163 build_id_valid: 164 id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i] 165 - vma->vm_start; 166 id_offs[i].status = BPF_STACK_BUILD_ID_VALID; 167 prev_vma = vma; 168 prev_build_id = id_offs[i].build_id; 169 } 170 bpf_mmap_unlock_mm(work, current->mm); 171 } 172 173 static struct perf_callchain_entry * 174 get_callchain_entry_for_task(struct task_struct *task, u32 max_depth) 175 { 176 #ifdef CONFIG_STACKTRACE 177 struct perf_callchain_entry *entry; 178 int rctx; 179 180 entry = get_callchain_entry(&rctx); 181 182 if (!entry) 183 return NULL; 184 185 entry->nr = stack_trace_save_tsk(task, (unsigned long *)entry->ip, 186 max_depth, 0); 187 188 /* stack_trace_save_tsk() works on unsigned long array, while 189 * perf_callchain_entry uses u64 array. For 32-bit systems, it is 190 * necessary to fix this mismatch. 191 */ 192 if (__BITS_PER_LONG != 64) { 193 unsigned long *from = (unsigned long *) entry->ip; 194 u64 *to = entry->ip; 195 int i; 196 197 /* copy data from the end to avoid using extra buffer */ 198 for (i = entry->nr - 1; i >= 0; i--) 199 to[i] = (u64)(from[i]); 200 } 201 202 put_callchain_entry(rctx); 203 204 return entry; 205 #else /* CONFIG_STACKTRACE */ 206 return NULL; 207 #endif 208 } 209 210 static long __bpf_get_stackid(struct bpf_map *map, 211 struct perf_callchain_entry *trace, u64 flags) 212 { 213 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 214 struct stack_map_bucket *bucket, *new_bucket, *old_bucket; 215 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 216 u32 hash, id, trace_nr, trace_len; 217 bool user = flags & BPF_F_USER_STACK; 218 u64 *ips; 219 bool hash_matches; 220 221 if (trace->nr <= skip) 222 /* skipping more than usable stack trace */ 223 return -EFAULT; 224 225 trace_nr = trace->nr - skip; 226 trace_len = trace_nr * sizeof(u64); 227 ips = trace->ip + skip; 228 hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0); 229 id = hash & (smap->n_buckets - 1); 230 bucket = READ_ONCE(smap->buckets[id]); 231 232 hash_matches = bucket && bucket->hash == hash; 233 /* fast cmp */ 234 if (hash_matches && flags & BPF_F_FAST_STACK_CMP) 235 return id; 236 237 if (stack_map_use_build_id(map)) { 238 /* for build_id+offset, pop a bucket before slow cmp */ 239 new_bucket = (struct stack_map_bucket *) 240 pcpu_freelist_pop(&smap->freelist); 241 if (unlikely(!new_bucket)) 242 return -ENOMEM; 243 new_bucket->nr = trace_nr; 244 stack_map_get_build_id_offset( 245 (struct bpf_stack_build_id *)new_bucket->data, 246 ips, trace_nr, user); 247 trace_len = trace_nr * sizeof(struct bpf_stack_build_id); 248 if (hash_matches && bucket->nr == trace_nr && 249 memcmp(bucket->data, new_bucket->data, trace_len) == 0) { 250 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); 251 return id; 252 } 253 if (bucket && !(flags & BPF_F_REUSE_STACKID)) { 254 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); 255 return -EEXIST; 256 } 257 } else { 258 if (hash_matches && bucket->nr == trace_nr && 259 memcmp(bucket->data, ips, trace_len) == 0) 260 return id; 261 if (bucket && !(flags & BPF_F_REUSE_STACKID)) 262 return -EEXIST; 263 264 new_bucket = (struct stack_map_bucket *) 265 pcpu_freelist_pop(&smap->freelist); 266 if (unlikely(!new_bucket)) 267 return -ENOMEM; 268 memcpy(new_bucket->data, ips, trace_len); 269 } 270 271 new_bucket->hash = hash; 272 new_bucket->nr = trace_nr; 273 274 old_bucket = xchg(&smap->buckets[id], new_bucket); 275 if (old_bucket) 276 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 277 return id; 278 } 279 280 BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, 281 u64, flags) 282 { 283 u32 max_depth = map->value_size / stack_map_data_size(map); 284 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 285 bool user = flags & BPF_F_USER_STACK; 286 struct perf_callchain_entry *trace; 287 bool kernel = !user; 288 289 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 290 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) 291 return -EINVAL; 292 293 max_depth += skip; 294 if (max_depth > sysctl_perf_event_max_stack) 295 max_depth = sysctl_perf_event_max_stack; 296 297 trace = get_perf_callchain(regs, 0, kernel, user, max_depth, 298 false, false); 299 300 if (unlikely(!trace)) 301 /* couldn't fetch the stack trace */ 302 return -EFAULT; 303 304 return __bpf_get_stackid(map, trace, flags); 305 } 306 307 const struct bpf_func_proto bpf_get_stackid_proto = { 308 .func = bpf_get_stackid, 309 .gpl_only = true, 310 .ret_type = RET_INTEGER, 311 .arg1_type = ARG_PTR_TO_CTX, 312 .arg2_type = ARG_CONST_MAP_PTR, 313 .arg3_type = ARG_ANYTHING, 314 }; 315 316 static __u64 count_kernel_ip(struct perf_callchain_entry *trace) 317 { 318 __u64 nr_kernel = 0; 319 320 while (nr_kernel < trace->nr) { 321 if (trace->ip[nr_kernel] == PERF_CONTEXT_USER) 322 break; 323 nr_kernel++; 324 } 325 return nr_kernel; 326 } 327 328 BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, 329 struct bpf_map *, map, u64, flags) 330 { 331 struct perf_event *event = ctx->event; 332 struct perf_callchain_entry *trace; 333 bool kernel, user; 334 __u64 nr_kernel; 335 int ret; 336 337 /* perf_sample_data doesn't have callchain, use bpf_get_stackid */ 338 if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)) 339 return bpf_get_stackid((unsigned long)(ctx->regs), 340 (unsigned long) map, flags, 0, 0); 341 342 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 343 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) 344 return -EINVAL; 345 346 user = flags & BPF_F_USER_STACK; 347 kernel = !user; 348 349 trace = ctx->data->callchain; 350 if (unlikely(!trace)) 351 return -EFAULT; 352 353 nr_kernel = count_kernel_ip(trace); 354 355 if (kernel) { 356 __u64 nr = trace->nr; 357 358 trace->nr = nr_kernel; 359 ret = __bpf_get_stackid(map, trace, flags); 360 361 /* restore nr */ 362 trace->nr = nr; 363 } else { /* user */ 364 u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 365 366 skip += nr_kernel; 367 if (skip > BPF_F_SKIP_FIELD_MASK) 368 return -EFAULT; 369 370 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; 371 ret = __bpf_get_stackid(map, trace, flags); 372 } 373 return ret; 374 } 375 376 const struct bpf_func_proto bpf_get_stackid_proto_pe = { 377 .func = bpf_get_stackid_pe, 378 .gpl_only = false, 379 .ret_type = RET_INTEGER, 380 .arg1_type = ARG_PTR_TO_CTX, 381 .arg2_type = ARG_CONST_MAP_PTR, 382 .arg3_type = ARG_ANYTHING, 383 }; 384 385 static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, 386 struct perf_callchain_entry *trace_in, 387 void *buf, u32 size, u64 flags) 388 { 389 u32 trace_nr, copy_len, elem_size, num_elem, max_depth; 390 bool user_build_id = flags & BPF_F_USER_BUILD_ID; 391 bool crosstask = task && task != current; 392 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 393 bool user = flags & BPF_F_USER_STACK; 394 struct perf_callchain_entry *trace; 395 bool kernel = !user; 396 int err = -EINVAL; 397 u64 *ips; 398 399 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 400 BPF_F_USER_BUILD_ID))) 401 goto clear; 402 if (kernel && user_build_id) 403 goto clear; 404 405 elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id) 406 : sizeof(u64); 407 if (unlikely(size % elem_size)) 408 goto clear; 409 410 /* cannot get valid user stack for task without user_mode regs */ 411 if (task && user && !user_mode(regs)) 412 goto err_fault; 413 414 /* get_perf_callchain does not support crosstask user stack walking 415 * but returns an empty stack instead of NULL. 416 */ 417 if (crosstask && user) { 418 err = -EOPNOTSUPP; 419 goto clear; 420 } 421 422 num_elem = size / elem_size; 423 max_depth = num_elem + skip; 424 if (sysctl_perf_event_max_stack < max_depth) 425 max_depth = sysctl_perf_event_max_stack; 426 427 if (trace_in) 428 trace = trace_in; 429 else if (kernel && task) 430 trace = get_callchain_entry_for_task(task, max_depth); 431 else 432 trace = get_perf_callchain(regs, 0, kernel, user, max_depth, 433 crosstask, false); 434 if (unlikely(!trace)) 435 goto err_fault; 436 437 if (trace->nr < skip) 438 goto err_fault; 439 440 trace_nr = trace->nr - skip; 441 trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem; 442 copy_len = trace_nr * elem_size; 443 444 ips = trace->ip + skip; 445 if (user && user_build_id) 446 stack_map_get_build_id_offset(buf, ips, trace_nr, user); 447 else 448 memcpy(buf, ips, copy_len); 449 450 if (size > copy_len) 451 memset(buf + copy_len, 0, size - copy_len); 452 return copy_len; 453 454 err_fault: 455 err = -EFAULT; 456 clear: 457 memset(buf, 0, size); 458 return err; 459 } 460 461 BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size, 462 u64, flags) 463 { 464 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); 465 } 466 467 const struct bpf_func_proto bpf_get_stack_proto = { 468 .func = bpf_get_stack, 469 .gpl_only = true, 470 .ret_type = RET_INTEGER, 471 .arg1_type = ARG_PTR_TO_CTX, 472 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 473 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 474 .arg4_type = ARG_ANYTHING, 475 }; 476 477 BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf, 478 u32, size, u64, flags) 479 { 480 struct pt_regs *regs; 481 long res = -EINVAL; 482 483 if (!try_get_task_stack(task)) 484 return -EFAULT; 485 486 regs = task_pt_regs(task); 487 if (regs) 488 res = __bpf_get_stack(regs, task, NULL, buf, size, flags); 489 put_task_stack(task); 490 491 return res; 492 } 493 494 const struct bpf_func_proto bpf_get_task_stack_proto = { 495 .func = bpf_get_task_stack, 496 .gpl_only = false, 497 .ret_type = RET_INTEGER, 498 .arg1_type = ARG_PTR_TO_BTF_ID, 499 .arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], 500 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 501 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 502 .arg4_type = ARG_ANYTHING, 503 }; 504 505 BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, 506 void *, buf, u32, size, u64, flags) 507 { 508 struct pt_regs *regs = (struct pt_regs *)(ctx->regs); 509 struct perf_event *event = ctx->event; 510 struct perf_callchain_entry *trace; 511 bool kernel, user; 512 int err = -EINVAL; 513 __u64 nr_kernel; 514 515 if (!(event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)) 516 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); 517 518 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 519 BPF_F_USER_BUILD_ID))) 520 goto clear; 521 522 user = flags & BPF_F_USER_STACK; 523 kernel = !user; 524 525 err = -EFAULT; 526 trace = ctx->data->callchain; 527 if (unlikely(!trace)) 528 goto clear; 529 530 nr_kernel = count_kernel_ip(trace); 531 532 if (kernel) { 533 __u64 nr = trace->nr; 534 535 trace->nr = nr_kernel; 536 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); 537 538 /* restore nr */ 539 trace->nr = nr; 540 } else { /* user */ 541 u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 542 543 skip += nr_kernel; 544 if (skip > BPF_F_SKIP_FIELD_MASK) 545 goto clear; 546 547 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; 548 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); 549 } 550 return err; 551 552 clear: 553 memset(buf, 0, size); 554 return err; 555 556 } 557 558 const struct bpf_func_proto bpf_get_stack_proto_pe = { 559 .func = bpf_get_stack_pe, 560 .gpl_only = true, 561 .ret_type = RET_INTEGER, 562 .arg1_type = ARG_PTR_TO_CTX, 563 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 564 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 565 .arg4_type = ARG_ANYTHING, 566 }; 567 568 /* Called from eBPF program */ 569 static void *stack_map_lookup_elem(struct bpf_map *map, void *key) 570 { 571 return ERR_PTR(-EOPNOTSUPP); 572 } 573 574 /* Called from syscall */ 575 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) 576 { 577 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 578 struct stack_map_bucket *bucket, *old_bucket; 579 u32 id = *(u32 *)key, trace_len; 580 581 if (unlikely(id >= smap->n_buckets)) 582 return -ENOENT; 583 584 bucket = xchg(&smap->buckets[id], NULL); 585 if (!bucket) 586 return -ENOENT; 587 588 trace_len = bucket->nr * stack_map_data_size(map); 589 memcpy(value, bucket->data, trace_len); 590 memset(value + trace_len, 0, map->value_size - trace_len); 591 592 old_bucket = xchg(&smap->buckets[id], bucket); 593 if (old_bucket) 594 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 595 return 0; 596 } 597 598 static int stack_map_get_next_key(struct bpf_map *map, void *key, 599 void *next_key) 600 { 601 struct bpf_stack_map *smap = container_of(map, 602 struct bpf_stack_map, map); 603 u32 id; 604 605 WARN_ON_ONCE(!rcu_read_lock_held()); 606 607 if (!key) { 608 id = 0; 609 } else { 610 id = *(u32 *)key; 611 if (id >= smap->n_buckets || !smap->buckets[id]) 612 id = 0; 613 else 614 id++; 615 } 616 617 while (id < smap->n_buckets && !smap->buckets[id]) 618 id++; 619 620 if (id >= smap->n_buckets) 621 return -ENOENT; 622 623 *(u32 *)next_key = id; 624 return 0; 625 } 626 627 static long stack_map_update_elem(struct bpf_map *map, void *key, void *value, 628 u64 map_flags) 629 { 630 return -EINVAL; 631 } 632 633 /* Called from syscall or from eBPF program */ 634 static long stack_map_delete_elem(struct bpf_map *map, void *key) 635 { 636 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 637 struct stack_map_bucket *old_bucket; 638 u32 id = *(u32 *)key; 639 640 if (unlikely(id >= smap->n_buckets)) 641 return -E2BIG; 642 643 old_bucket = xchg(&smap->buckets[id], NULL); 644 if (old_bucket) { 645 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 646 return 0; 647 } else { 648 return -ENOENT; 649 } 650 } 651 652 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */ 653 static void stack_map_free(struct bpf_map *map) 654 { 655 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 656 657 bpf_map_area_free(smap->elems); 658 pcpu_freelist_destroy(&smap->freelist); 659 bpf_map_area_free(smap); 660 put_callchain_buffers(); 661 } 662 663 static u64 stack_map_mem_usage(const struct bpf_map *map) 664 { 665 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 666 u64 value_size = map->value_size; 667 u64 n_buckets = smap->n_buckets; 668 u64 enties = map->max_entries; 669 u64 usage = sizeof(*smap); 670 671 usage += n_buckets * sizeof(struct stack_map_bucket *); 672 usage += enties * (sizeof(struct stack_map_bucket) + value_size); 673 return usage; 674 } 675 676 BTF_ID_LIST_SINGLE(stack_trace_map_btf_ids, struct, bpf_stack_map) 677 const struct bpf_map_ops stack_trace_map_ops = { 678 .map_meta_equal = bpf_map_meta_equal, 679 .map_alloc = stack_map_alloc, 680 .map_free = stack_map_free, 681 .map_get_next_key = stack_map_get_next_key, 682 .map_lookup_elem = stack_map_lookup_elem, 683 .map_update_elem = stack_map_update_elem, 684 .map_delete_elem = stack_map_delete_elem, 685 .map_check_btf = map_check_no_btf, 686 .map_mem_usage = stack_map_mem_usage, 687 .map_btf_id = &stack_trace_map_btf_ids[0], 688 }; 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