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 max_depth) 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 = stack_trace_save_tsk(task, (unsigned long *)entry->ip, 191 max_depth, 0); 192 193 /* stack_trace_save_tsk() works on unsigned long array, while 194 * perf_callchain_entry uses u64 array. For 32-bit systems, it is 195 * necessary to fix this mismatch. 196 */ 197 if (__BITS_PER_LONG != 64) { 198 unsigned long *from = (unsigned long *) entry->ip; 199 u64 *to = entry->ip; 200 int i; 201 202 /* copy data from the end to avoid using extra buffer */ 203 for (i = entry->nr - 1; i >= 0; i--) 204 to[i] = (u64)(from[i]); 205 } 206 207 put_callchain_entry(rctx); 208 209 return entry; 210 #else /* CONFIG_STACKTRACE */ 211 return NULL; 212 #endif 213 } 214 215 static long __bpf_get_stackid(struct bpf_map *map, 216 struct perf_callchain_entry *trace, u64 flags) 217 { 218 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 219 struct stack_map_bucket *bucket, *new_bucket, *old_bucket; 220 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 221 u32 hash, id, trace_nr, trace_len; 222 bool user = flags & BPF_F_USER_STACK; 223 u64 *ips; 224 bool hash_matches; 225 226 if (trace->nr <= skip) 227 /* skipping more than usable stack trace */ 228 return -EFAULT; 229 230 trace_nr = trace->nr - skip; 231 trace_len = trace_nr * sizeof(u64); 232 ips = trace->ip + skip; 233 hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0); 234 id = hash & (smap->n_buckets - 1); 235 bucket = READ_ONCE(smap->buckets[id]); 236 237 hash_matches = bucket && bucket->hash == hash; 238 /* fast cmp */ 239 if (hash_matches && flags & BPF_F_FAST_STACK_CMP) 240 return id; 241 242 if (stack_map_use_build_id(map)) { 243 /* for build_id+offset, pop a bucket before slow cmp */ 244 new_bucket = (struct stack_map_bucket *) 245 pcpu_freelist_pop(&smap->freelist); 246 if (unlikely(!new_bucket)) 247 return -ENOMEM; 248 new_bucket->nr = trace_nr; 249 stack_map_get_build_id_offset( 250 (struct bpf_stack_build_id *)new_bucket->data, 251 ips, trace_nr, user); 252 trace_len = trace_nr * sizeof(struct bpf_stack_build_id); 253 if (hash_matches && bucket->nr == trace_nr && 254 memcmp(bucket->data, new_bucket->data, trace_len) == 0) { 255 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); 256 return id; 257 } 258 if (bucket && !(flags & BPF_F_REUSE_STACKID)) { 259 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode); 260 return -EEXIST; 261 } 262 } else { 263 if (hash_matches && bucket->nr == trace_nr && 264 memcmp(bucket->data, ips, trace_len) == 0) 265 return id; 266 if (bucket && !(flags & BPF_F_REUSE_STACKID)) 267 return -EEXIST; 268 269 new_bucket = (struct stack_map_bucket *) 270 pcpu_freelist_pop(&smap->freelist); 271 if (unlikely(!new_bucket)) 272 return -ENOMEM; 273 memcpy(new_bucket->data, ips, trace_len); 274 } 275 276 new_bucket->hash = hash; 277 new_bucket->nr = trace_nr; 278 279 old_bucket = xchg(&smap->buckets[id], new_bucket); 280 if (old_bucket) 281 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 282 return id; 283 } 284 285 BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map, 286 u64, flags) 287 { 288 u32 max_depth = map->value_size / stack_map_data_size(map); 289 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 290 bool user = flags & BPF_F_USER_STACK; 291 struct perf_callchain_entry *trace; 292 bool kernel = !user; 293 294 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 295 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) 296 return -EINVAL; 297 298 max_depth += skip; 299 if (max_depth > sysctl_perf_event_max_stack) 300 max_depth = sysctl_perf_event_max_stack; 301 302 trace = get_perf_callchain(regs, 0, kernel, user, max_depth, 303 false, false); 304 305 if (unlikely(!trace)) 306 /* couldn't fetch the stack trace */ 307 return -EFAULT; 308 309 return __bpf_get_stackid(map, trace, flags); 310 } 311 312 const struct bpf_func_proto bpf_get_stackid_proto = { 313 .func = bpf_get_stackid, 314 .gpl_only = true, 315 .ret_type = RET_INTEGER, 316 .arg1_type = ARG_PTR_TO_CTX, 317 .arg2_type = ARG_CONST_MAP_PTR, 318 .arg3_type = ARG_ANYTHING, 319 }; 320 321 static __u64 count_kernel_ip(struct perf_callchain_entry *trace) 322 { 323 __u64 nr_kernel = 0; 324 325 while (nr_kernel < trace->nr) { 326 if (trace->ip[nr_kernel] == PERF_CONTEXT_USER) 327 break; 328 nr_kernel++; 329 } 330 return nr_kernel; 331 } 332 333 BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx, 334 struct bpf_map *, map, u64, flags) 335 { 336 struct perf_event *event = ctx->event; 337 struct perf_callchain_entry *trace; 338 bool kernel, user; 339 __u64 nr_kernel; 340 int ret; 341 342 /* perf_sample_data doesn't have callchain, use bpf_get_stackid */ 343 if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) 344 return bpf_get_stackid((unsigned long)(ctx->regs), 345 (unsigned long) map, flags, 0, 0); 346 347 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 348 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID))) 349 return -EINVAL; 350 351 user = flags & BPF_F_USER_STACK; 352 kernel = !user; 353 354 trace = ctx->data->callchain; 355 if (unlikely(!trace)) 356 return -EFAULT; 357 358 nr_kernel = count_kernel_ip(trace); 359 360 if (kernel) { 361 __u64 nr = trace->nr; 362 363 trace->nr = nr_kernel; 364 ret = __bpf_get_stackid(map, trace, flags); 365 366 /* restore nr */ 367 trace->nr = nr; 368 } else { /* user */ 369 u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 370 371 skip += nr_kernel; 372 if (skip > BPF_F_SKIP_FIELD_MASK) 373 return -EFAULT; 374 375 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; 376 ret = __bpf_get_stackid(map, trace, flags); 377 } 378 return ret; 379 } 380 381 const struct bpf_func_proto bpf_get_stackid_proto_pe = { 382 .func = bpf_get_stackid_pe, 383 .gpl_only = false, 384 .ret_type = RET_INTEGER, 385 .arg1_type = ARG_PTR_TO_CTX, 386 .arg2_type = ARG_CONST_MAP_PTR, 387 .arg3_type = ARG_ANYTHING, 388 }; 389 390 static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task, 391 struct perf_callchain_entry *trace_in, 392 void *buf, u32 size, u64 flags) 393 { 394 u32 trace_nr, copy_len, elem_size, num_elem, max_depth; 395 bool user_build_id = flags & BPF_F_USER_BUILD_ID; 396 u32 skip = flags & BPF_F_SKIP_FIELD_MASK; 397 bool user = flags & BPF_F_USER_STACK; 398 struct perf_callchain_entry *trace; 399 bool kernel = !user; 400 int err = -EINVAL; 401 u64 *ips; 402 403 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 404 BPF_F_USER_BUILD_ID))) 405 goto clear; 406 if (kernel && user_build_id) 407 goto clear; 408 409 elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id) 410 : sizeof(u64); 411 if (unlikely(size % elem_size)) 412 goto clear; 413 414 /* cannot get valid user stack for task without user_mode regs */ 415 if (task && user && !user_mode(regs)) 416 goto err_fault; 417 418 num_elem = size / elem_size; 419 max_depth = num_elem + skip; 420 if (sysctl_perf_event_max_stack < max_depth) 421 max_depth = sysctl_perf_event_max_stack; 422 423 if (trace_in) 424 trace = trace_in; 425 else if (kernel && task) 426 trace = get_callchain_entry_for_task(task, max_depth); 427 else 428 trace = get_perf_callchain(regs, 0, kernel, user, max_depth, 429 false, false); 430 if (unlikely(!trace)) 431 goto err_fault; 432 433 if (trace->nr < skip) 434 goto err_fault; 435 436 trace_nr = trace->nr - skip; 437 trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem; 438 copy_len = trace_nr * elem_size; 439 440 ips = trace->ip + skip; 441 if (user && user_build_id) 442 stack_map_get_build_id_offset(buf, ips, trace_nr, user); 443 else 444 memcpy(buf, ips, copy_len); 445 446 if (size > copy_len) 447 memset(buf + copy_len, 0, size - copy_len); 448 return copy_len; 449 450 err_fault: 451 err = -EFAULT; 452 clear: 453 memset(buf, 0, size); 454 return err; 455 } 456 457 BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size, 458 u64, flags) 459 { 460 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); 461 } 462 463 const struct bpf_func_proto bpf_get_stack_proto = { 464 .func = bpf_get_stack, 465 .gpl_only = true, 466 .ret_type = RET_INTEGER, 467 .arg1_type = ARG_PTR_TO_CTX, 468 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 469 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 470 .arg4_type = ARG_ANYTHING, 471 }; 472 473 BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf, 474 u32, size, u64, flags) 475 { 476 struct pt_regs *regs; 477 long res = -EINVAL; 478 479 if (!try_get_task_stack(task)) 480 return -EFAULT; 481 482 regs = task_pt_regs(task); 483 if (regs) 484 res = __bpf_get_stack(regs, task, NULL, buf, size, flags); 485 put_task_stack(task); 486 487 return res; 488 } 489 490 const struct bpf_func_proto bpf_get_task_stack_proto = { 491 .func = bpf_get_task_stack, 492 .gpl_only = false, 493 .ret_type = RET_INTEGER, 494 .arg1_type = ARG_PTR_TO_BTF_ID, 495 .arg1_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK], 496 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 497 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 498 .arg4_type = ARG_ANYTHING, 499 }; 500 501 BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx, 502 void *, buf, u32, size, u64, flags) 503 { 504 struct pt_regs *regs = (struct pt_regs *)(ctx->regs); 505 struct perf_event *event = ctx->event; 506 struct perf_callchain_entry *trace; 507 bool kernel, user; 508 int err = -EINVAL; 509 __u64 nr_kernel; 510 511 if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY)) 512 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags); 513 514 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK | 515 BPF_F_USER_BUILD_ID))) 516 goto clear; 517 518 user = flags & BPF_F_USER_STACK; 519 kernel = !user; 520 521 err = -EFAULT; 522 trace = ctx->data->callchain; 523 if (unlikely(!trace)) 524 goto clear; 525 526 nr_kernel = count_kernel_ip(trace); 527 528 if (kernel) { 529 __u64 nr = trace->nr; 530 531 trace->nr = nr_kernel; 532 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); 533 534 /* restore nr */ 535 trace->nr = nr; 536 } else { /* user */ 537 u64 skip = flags & BPF_F_SKIP_FIELD_MASK; 538 539 skip += nr_kernel; 540 if (skip > BPF_F_SKIP_FIELD_MASK) 541 goto clear; 542 543 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip; 544 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags); 545 } 546 return err; 547 548 clear: 549 memset(buf, 0, size); 550 return err; 551 552 } 553 554 const struct bpf_func_proto bpf_get_stack_proto_pe = { 555 .func = bpf_get_stack_pe, 556 .gpl_only = true, 557 .ret_type = RET_INTEGER, 558 .arg1_type = ARG_PTR_TO_CTX, 559 .arg2_type = ARG_PTR_TO_UNINIT_MEM, 560 .arg3_type = ARG_CONST_SIZE_OR_ZERO, 561 .arg4_type = ARG_ANYTHING, 562 }; 563 564 /* Called from eBPF program */ 565 static void *stack_map_lookup_elem(struct bpf_map *map, void *key) 566 { 567 return ERR_PTR(-EOPNOTSUPP); 568 } 569 570 /* Called from syscall */ 571 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value) 572 { 573 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 574 struct stack_map_bucket *bucket, *old_bucket; 575 u32 id = *(u32 *)key, trace_len; 576 577 if (unlikely(id >= smap->n_buckets)) 578 return -ENOENT; 579 580 bucket = xchg(&smap->buckets[id], NULL); 581 if (!bucket) 582 return -ENOENT; 583 584 trace_len = bucket->nr * stack_map_data_size(map); 585 memcpy(value, bucket->data, trace_len); 586 memset(value + trace_len, 0, map->value_size - trace_len); 587 588 old_bucket = xchg(&smap->buckets[id], bucket); 589 if (old_bucket) 590 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 591 return 0; 592 } 593 594 static int stack_map_get_next_key(struct bpf_map *map, void *key, 595 void *next_key) 596 { 597 struct bpf_stack_map *smap = container_of(map, 598 struct bpf_stack_map, map); 599 u32 id; 600 601 WARN_ON_ONCE(!rcu_read_lock_held()); 602 603 if (!key) { 604 id = 0; 605 } else { 606 id = *(u32 *)key; 607 if (id >= smap->n_buckets || !smap->buckets[id]) 608 id = 0; 609 else 610 id++; 611 } 612 613 while (id < smap->n_buckets && !smap->buckets[id]) 614 id++; 615 616 if (id >= smap->n_buckets) 617 return -ENOENT; 618 619 *(u32 *)next_key = id; 620 return 0; 621 } 622 623 static int stack_map_update_elem(struct bpf_map *map, void *key, void *value, 624 u64 map_flags) 625 { 626 return -EINVAL; 627 } 628 629 /* Called from syscall or from eBPF program */ 630 static int stack_map_delete_elem(struct bpf_map *map, void *key) 631 { 632 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 633 struct stack_map_bucket *old_bucket; 634 u32 id = *(u32 *)key; 635 636 if (unlikely(id >= smap->n_buckets)) 637 return -E2BIG; 638 639 old_bucket = xchg(&smap->buckets[id], NULL); 640 if (old_bucket) { 641 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode); 642 return 0; 643 } else { 644 return -ENOENT; 645 } 646 } 647 648 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */ 649 static void stack_map_free(struct bpf_map *map) 650 { 651 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map); 652 653 bpf_map_area_free(smap->elems); 654 pcpu_freelist_destroy(&smap->freelist); 655 bpf_map_area_free(smap); 656 put_callchain_buffers(); 657 } 658 659 static int stack_trace_map_btf_id; 660 const struct bpf_map_ops stack_trace_map_ops = { 661 .map_meta_equal = bpf_map_meta_equal, 662 .map_alloc = stack_map_alloc, 663 .map_free = stack_map_free, 664 .map_get_next_key = stack_map_get_next_key, 665 .map_lookup_elem = stack_map_lookup_elem, 666 .map_update_elem = stack_map_update_elem, 667 .map_delete_elem = stack_map_delete_elem, 668 .map_check_btf = map_check_no_btf, 669 .map_btf_name = "bpf_stack_map", 670 .map_btf_id = &stack_trace_map_btf_id, 671 }; 672