tools/perf/util/bpf-event.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <errno.h>
   3 #include <stdlib.h>
   4 #include <bpf/bpf.h>
   5 #include <bpf/btf.h>
   6 #include <bpf/libbpf.h>
   7 #include <linux/btf.h>
   8 #include <linux/err.h>
   9 #include <linux/string.h>
  10 #include <internal/lib.h>
  11 #include <symbol/kallsyms.h>
  12 #include "bpf-event.h"
  13 #include "bpf-utils.h"
  14 #include "debug.h"
  15 #include "dso.h"
  16 #include "symbol.h"
  17 #include "machine.h"
  18 #include "env.h"
  19 #include "session.h"
  20 #include "map.h"
  21 #include "evlist.h"
  22 #include "record.h"
  23 #include "util/synthetic-events.h"
  24
  25 #ifndef HAVE_LIBBPF_BTF__LOAD_FROM_KERNEL_BY_ID
  26 struct btf *btf__load_from_kernel_by_id(__u32 id)
  27 {
  28        struct btf *btf;
  29 #pragma GCC diagnostic push
  30 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  31        int err = btf__get_from_id(id, &btf);
  32 #pragma GCC diagnostic pop
  33
  34        return err ? ERR_PTR(err) : btf;
  35 }
  36 #endif
  37
  38 #ifndef HAVE_LIBBPF_BPF_PROG_LOAD
  39 LIBBPF_API int bpf_load_program(enum bpf_prog_type type,
  40                                 const struct bpf_insn *insns, size_t insns_cnt,
  41                                 const char *license, __u32 kern_version,
  42                                 char *log_buf, size_t log_buf_sz);
  43
  44 int bpf_prog_load(enum bpf_prog_type prog_type,
  45                   const char *prog_name __maybe_unused,
  46                   const char *license,
  47                   const struct bpf_insn *insns, size_t insn_cnt,
  48                   const struct bpf_prog_load_opts *opts)
  49 {
  50 #pragma GCC diagnostic push
  51 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  52         return bpf_load_program(prog_type, insns, insn_cnt, license,
  53                                 opts->kern_version, opts->log_buf, opts->log_size);
  54 #pragma GCC diagnostic pop
  55 }
  56 #endif
  57
  58 #ifndef HAVE_LIBBPF_BPF_OBJECT__NEXT_PROGRAM
  59 struct bpf_program *
  60 bpf_object__next_program(const struct bpf_object *obj, struct bpf_program *prev)
  61 {
  62 #pragma GCC diagnostic push
  63 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  64         return bpf_program__next(prev, obj);
  65 #pragma GCC diagnostic pop
  66 }
  67 #endif
  68
  69 #ifndef HAVE_LIBBPF_BPF_OBJECT__NEXT_MAP
  70 struct bpf_map *
  71 bpf_object__next_map(const struct bpf_object *obj, const struct bpf_map *prev)
  72 {
  73 #pragma GCC diagnostic push
  74 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  75         return bpf_map__next(prev, obj);
  76 #pragma GCC diagnostic pop
  77 }
  78 #endif
  79
  80 #ifndef HAVE_LIBBPF_BTF__RAW_DATA
  81 const void *
  82 btf__raw_data(const struct btf *btf_ro, __u32 *size)
  83 {
  84 #pragma GCC diagnostic push
  85 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
  86         return btf__get_raw_data(btf_ro, size);
  87 #pragma GCC diagnostic pop
  88 }
  89 #endif
  90
  91 static int snprintf_hex(char *buf, size_t size, unsigned char *data, size_t len)
  92 {
  93         int ret = 0;
  94         size_t i;
  95
  96         for (i = 0; i < len; i++)
  97                 ret += snprintf(buf + ret, size - ret, "%02x", data[i]);
  98         return ret;
  99 }
 100
 101 static int machine__process_bpf_event_load(struct machine *machine,
 102                                            union perf_event *event,
 103                                            struct perf_sample *sample __maybe_unused)
 104 {
 105         struct bpf_prog_info_node *info_node;
 106         struct perf_env *env = machine->env;
 107         struct perf_bpil *info_linear;
 108         int id = event->bpf.id;
 109         unsigned int i;
 110
 111         /* perf-record, no need to handle bpf-event */
 112         if (env == NULL)
 113                 return 0;
 114
 115         info_node = perf_env__find_bpf_prog_info(env, id);
 116         if (!info_node)
 117                 return 0;
 118         info_linear = info_node->info_linear;
 119
 120         for (i = 0; i < info_linear->info.nr_jited_ksyms; i++) {
 121                 u64 *addrs = (u64 *)(uintptr_t)(info_linear->info.jited_ksyms);
 122                 u64 addr = addrs[i];
 123                 struct map *map = maps__find(machine__kernel_maps(machine), addr);
 124
 125                 if (map) {
 126                         map->dso->binary_type = DSO_BINARY_TYPE__BPF_PROG_INFO;
 127                         map->dso->bpf_prog.id = id;
 128                         map->dso->bpf_prog.sub_id = i;
 129                         map->dso->bpf_prog.env = env;
 130                 }
 131         }
 132         return 0;
 133 }
 134
 135 int machine__process_bpf(struct machine *machine, union perf_event *event,
 136                          struct perf_sample *sample)
 137 {
 138         if (dump_trace)
 139                 perf_event__fprintf_bpf(event, stdout);
 140
 141         switch (event->bpf.type) {
 142         case PERF_BPF_EVENT_PROG_LOAD:
 143                 return machine__process_bpf_event_load(machine, event, sample);
 144
 145         case PERF_BPF_EVENT_PROG_UNLOAD:
 146                 /*
 147                  * Do not free bpf_prog_info and btf of the program here,
 148                  * as annotation still need them. They will be freed at
 149                  * the end of the session.
 150                  */
 151                 break;
 152         default:
 153                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 154                 break;
 155         }
 156         return 0;
 157 }
 158
 159 static int perf_env__fetch_btf(struct perf_env *env,
 160                                u32 btf_id,
 161                                struct btf *btf)
 162 {
 163         struct btf_node *node;
 164         u32 data_size;
 165         const void *data;
 166
 167         data = btf__raw_data(btf, &data_size);
 168
 169         node = malloc(data_size + sizeof(struct btf_node));
 170         if (!node)
 171                 return -1;
 172
 173         node->id = btf_id;
 174         node->data_size = data_size;
 175         memcpy(node->data, data, data_size);
 176
 177         if (!perf_env__insert_btf(env, node)) {
 178                 /* Insertion failed because of a duplicate. */
 179                 free(node);
 180                 return -1;
 181         }
 182         return 0;
 183 }
 184
 185 static int synthesize_bpf_prog_name(char *buf, int size,
 186                                     struct bpf_prog_info *info,
 187                                     struct btf *btf,
 188                                     u32 sub_id)
 189 {
 190         u8 (*prog_tags)[BPF_TAG_SIZE] = (void *)(uintptr_t)(info->prog_tags);
 191         void *func_infos = (void *)(uintptr_t)(info->func_info);
 192         u32 sub_prog_cnt = info->nr_jited_ksyms;
 193         const struct bpf_func_info *finfo;
 194         const char *short_name = NULL;
 195         const struct btf_type *t;
 196         int name_len;
 197
 198         name_len = snprintf(buf, size, "bpf_prog_");
 199         name_len += snprintf_hex(buf + name_len, size - name_len,
 200                                  prog_tags[sub_id], BPF_TAG_SIZE);
 201         if (btf) {
 202                 finfo = func_infos + sub_id * info->func_info_rec_size;
 203                 t = btf__type_by_id(btf, finfo->type_id);
 204                 short_name = btf__name_by_offset(btf, t->name_off);
 205         } else if (sub_id == 0 && sub_prog_cnt == 1) {
 206                 /* no subprog */
 207                 if (info->name[0])
 208                         short_name = info->name;
 209         } else
 210                 short_name = "F";
 211         if (short_name)
 212                 name_len += snprintf(buf + name_len, size - name_len,
 213                                      "_%s", short_name);
 214         return name_len;
 215 }
 216
 217 /*
 218  * Synthesize PERF_RECORD_KSYMBOL and PERF_RECORD_BPF_EVENT for one bpf
 219  * program. One PERF_RECORD_BPF_EVENT is generated for the program. And
 220  * one PERF_RECORD_KSYMBOL is generated for each sub program.
 221  *
 222  * Returns:
 223  *    0 for success;
 224  *   -1 for failures;
 225  *   -2 for lack of kernel support.
 226  */
 227 static int perf_event__synthesize_one_bpf_prog(struct perf_session *session,
 228                                                perf_event__handler_t process,
 229                                                struct machine *machine,
 230                                                int fd,
 231                                                union perf_event *event,
 232                                                struct record_opts *opts)
 233 {
 234         struct perf_record_ksymbol *ksymbol_event = &event->ksymbol;
 235         struct perf_record_bpf_event *bpf_event = &event->bpf;
 236         struct perf_tool *tool = session->tool;
 237         struct bpf_prog_info_node *info_node;
 238         struct perf_bpil *info_linear;
 239         struct bpf_prog_info *info;
 240         struct btf *btf = NULL;
 241         struct perf_env *env;
 242         u32 sub_prog_cnt, i;
 243         int err = 0;
 244         u64 arrays;
 245
 246         /*
 247          * for perf-record and perf-report use header.env;
 248          * otherwise, use global perf_env.
 249          */
 250         env = session->data ? &session->header.env : &perf_env;
 251
 252         arrays = 1UL << PERF_BPIL_JITED_KSYMS;
 253         arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
 254         arrays |= 1UL << PERF_BPIL_FUNC_INFO;
 255         arrays |= 1UL << PERF_BPIL_PROG_TAGS;
 256         arrays |= 1UL << PERF_BPIL_JITED_INSNS;
 257         arrays |= 1UL << PERF_BPIL_LINE_INFO;
 258         arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
 259
 260         info_linear = get_bpf_prog_info_linear(fd, arrays);
 261         if (IS_ERR_OR_NULL(info_linear)) {
 262                 info_linear = NULL;
 263                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 264                 return -1;
 265         }
 266
 267         if (info_linear->info_len < offsetof(struct bpf_prog_info, prog_tags)) {
 268                 free(info_linear);
 269                 pr_debug("%s: the kernel is too old, aborting\n", __func__);
 270                 return -2;
 271         }
 272
 273         info = &info_linear->info;
 274         if (!info->jited_ksyms) {
 275                 free(info_linear);
 276                 return -1;
 277         }
 278
 279         /* number of ksyms, func_lengths, and tags should match */
 280         sub_prog_cnt = info->nr_jited_ksyms;
 281         if (sub_prog_cnt != info->nr_prog_tags ||
 282             sub_prog_cnt != info->nr_jited_func_lens) {
 283                 free(info_linear);
 284                 return -1;
 285         }
 286
 287         /* check BTF func info support */
 288         if (info->btf_id && info->nr_func_info && info->func_info_rec_size) {
 289                 /* btf func info number should be same as sub_prog_cnt */
 290                 if (sub_prog_cnt != info->nr_func_info) {
 291                         pr_debug("%s: mismatch in BPF sub program count and BTF function info count, aborting\n", __func__);
 292                         free(info_linear);
 293                         return -1;
 294                 }
 295                 btf = btf__load_from_kernel_by_id(info->btf_id);
 296                 if (libbpf_get_error(btf)) {
 297                         pr_debug("%s: failed to get BTF of id %u, aborting\n", __func__, info->btf_id);
 298                         err = -1;
 299                         goto out;
 300                 }
 301                 perf_env__fetch_btf(env, info->btf_id, btf);
 302         }
 303
 304         /* Synthesize PERF_RECORD_KSYMBOL */
 305         for (i = 0; i < sub_prog_cnt; i++) {
 306                 __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 307                 __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 308                 int name_len;
 309
 310                 *ksymbol_event = (struct perf_record_ksymbol) {
 311                         .header = {
 312                                 .type = PERF_RECORD_KSYMBOL,
 313                                 .size = offsetof(struct perf_record_ksymbol, name),
 314                         },
 315                         .addr = prog_addrs[i],
 316                         .len = prog_lens[i],
 317                         .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 318                         .flags = 0,
 319                 };
 320
 321                 name_len = synthesize_bpf_prog_name(ksymbol_event->name,
 322                                                     KSYM_NAME_LEN, info, btf, i);
 323                 ksymbol_event->header.size += PERF_ALIGN(name_len + 1,
 324                                                          sizeof(u64));
 325
 326                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 327                 event->header.size += machine->id_hdr_size;
 328                 err = perf_tool__process_synth_event(tool, event,
 329                                                      machine, process);
 330         }
 331
 332         if (!opts->no_bpf_event) {
 333                 /* Synthesize PERF_RECORD_BPF_EVENT */
 334                 *bpf_event = (struct perf_record_bpf_event) {
 335                         .header = {
 336                                 .type = PERF_RECORD_BPF_EVENT,
 337                                 .size = sizeof(struct perf_record_bpf_event),
 338                         },
 339                         .type = PERF_BPF_EVENT_PROG_LOAD,
 340                         .flags = 0,
 341                         .id = info->id,
 342                 };
 343                 memcpy(bpf_event->tag, info->tag, BPF_TAG_SIZE);
 344                 memset((void *)event + event->header.size, 0, machine->id_hdr_size);
 345                 event->header.size += machine->id_hdr_size;
 346
 347                 /* save bpf_prog_info to env */
 348                 info_node = malloc(sizeof(struct bpf_prog_info_node));
 349                 if (!info_node) {
 350                         err = -1;
 351                         goto out;
 352                 }
 353
 354                 info_node->info_linear = info_linear;
 355                 perf_env__insert_bpf_prog_info(env, info_node);
 356                 info_linear = NULL;
 357
 358                 /*
 359                  * process after saving bpf_prog_info to env, so that
 360                  * required information is ready for look up
 361                  */
 362                 err = perf_tool__process_synth_event(tool, event,
 363                                                      machine, process);
 364         }
 365
 366 out:
 367         free(info_linear);
 368         btf__free(btf);
 369         return err ? -1 : 0;
 370 }
 371
 372 struct kallsyms_parse {
 373         union perf_event        *event;
 374         perf_event__handler_t    process;
 375         struct machine          *machine;
 376         struct perf_tool        *tool;
 377 };
 378
 379 static int
 380 process_bpf_image(char *name, u64 addr, struct kallsyms_parse *data)
 381 {
 382         struct machine *machine = data->machine;
 383         union perf_event *event = data->event;
 384         struct perf_record_ksymbol *ksymbol;
 385         int len;
 386
 387         ksymbol = &event->ksymbol;
 388
 389         *ksymbol = (struct perf_record_ksymbol) {
 390                 .header = {
 391                         .type = PERF_RECORD_KSYMBOL,
 392                         .size = offsetof(struct perf_record_ksymbol, name),
 393                 },
 394                 .addr      = addr,
 395                 .len       = page_size,
 396                 .ksym_type = PERF_RECORD_KSYMBOL_TYPE_BPF,
 397                 .flags     = 0,
 398         };
 399
 400         len = scnprintf(ksymbol->name, KSYM_NAME_LEN, "%s", name);
 401         ksymbol->header.size += PERF_ALIGN(len + 1, sizeof(u64));
 402         memset((void *) event + event->header.size, 0, machine->id_hdr_size);
 403         event->header.size += machine->id_hdr_size;
 404
 405         return perf_tool__process_synth_event(data->tool, event, machine,
 406                                               data->process);
 407 }
 408
 409 static int
 410 kallsyms_process_symbol(void *data, const char *_name,
 411                         char type __maybe_unused, u64 start)
 412 {
 413         char disp[KSYM_NAME_LEN];
 414         char *module, *name;
 415         unsigned long id;
 416         int err = 0;
 417
 418         module = strchr(_name, '\t');
 419         if (!module)
 420                 return 0;
 421
 422         /* We are going after [bpf] module ... */
 423         if (strcmp(module + 1, "[bpf]"))
 424                 return 0;
 425
 426         name = memdup(_name, (module - _name) + 1);
 427         if (!name)
 428                 return -ENOMEM;
 429
 430         name[module - _name] = 0;
 431
 432         /* .. and only for trampolines and dispatchers */
 433         if ((sscanf(name, "bpf_trampoline_%lu", &id) == 1) ||
 434             (sscanf(name, "bpf_dispatcher_%s", disp) == 1))
 435                 err = process_bpf_image(name, start, data);
 436
 437         free(name);
 438         return err;
 439 }
 440
 441 int perf_event__synthesize_bpf_events(struct perf_session *session,
 442                                       perf_event__handler_t process,
 443                                       struct machine *machine,
 444                                       struct record_opts *opts)
 445 {
 446         const char *kallsyms_filename = "/proc/kallsyms";
 447         struct kallsyms_parse arg;
 448         union perf_event *event;
 449         __u32 id = 0;
 450         int err;
 451         int fd;
 452
 453         event = malloc(sizeof(event->bpf) + KSYM_NAME_LEN + machine->id_hdr_size);
 454         if (!event)
 455                 return -1;
 456
 457         /* Synthesize all the bpf programs in system. */
 458         while (true) {
 459                 err = bpf_prog_get_next_id(id, &id);
 460                 if (err) {
 461                         if (errno == ENOENT) {
 462                                 err = 0;
 463                                 break;
 464                         }
 465                         pr_debug("%s: can't get next program: %s%s\n",
 466                                  __func__, strerror(errno),
 467                                  errno == EINVAL ? " -- kernel too old?" : "");
 468                         /* don't report error on old kernel or EPERM  */
 469                         err = (errno == EINVAL || errno == EPERM) ? 0 : -1;
 470                         break;
 471                 }
 472                 fd = bpf_prog_get_fd_by_id(id);
 473                 if (fd < 0) {
 474                         pr_debug("%s: failed to get fd for prog_id %u\n",
 475                                  __func__, id);
 476                         continue;
 477                 }
 478
 479                 err = perf_event__synthesize_one_bpf_prog(session, process,
 480                                                           machine, fd,
 481                                                           event, opts);
 482                 close(fd);
 483                 if (err) {
 484                         /* do not return error for old kernel */
 485                         if (err == -2)
 486                                 err = 0;
 487                         break;
 488                 }
 489         }
 490
 491         /* Synthesize all the bpf images - trampolines/dispatchers. */
 492         if (symbol_conf.kallsyms_name != NULL)
 493                 kallsyms_filename = symbol_conf.kallsyms_name;
 494
 495         arg = (struct kallsyms_parse) {
 496                 .event   = event,
 497                 .process = process,
 498                 .machine = machine,
 499                 .tool    = session->tool,
 500         };
 501
 502         if (kallsyms__parse(kallsyms_filename, &arg, kallsyms_process_symbol)) {
 503                 pr_err("%s: failed to synthesize bpf images: %s\n",
 504                        __func__, strerror(errno));
 505         }
 506
 507         free(event);
 508         return err;
 509 }
 510
 511 static void perf_env__add_bpf_info(struct perf_env *env, u32 id)
 512 {
 513         struct bpf_prog_info_node *info_node;
 514         struct perf_bpil *info_linear;
 515         struct btf *btf = NULL;
 516         u64 arrays;
 517         u32 btf_id;
 518         int fd;
 519
 520         fd = bpf_prog_get_fd_by_id(id);
 521         if (fd < 0)
 522                 return;
 523
 524         arrays = 1UL << PERF_BPIL_JITED_KSYMS;
 525         arrays |= 1UL << PERF_BPIL_JITED_FUNC_LENS;
 526         arrays |= 1UL << PERF_BPIL_FUNC_INFO;
 527         arrays |= 1UL << PERF_BPIL_PROG_TAGS;
 528         arrays |= 1UL << PERF_BPIL_JITED_INSNS;
 529         arrays |= 1UL << PERF_BPIL_LINE_INFO;
 530         arrays |= 1UL << PERF_BPIL_JITED_LINE_INFO;
 531
 532         info_linear = get_bpf_prog_info_linear(fd, arrays);
 533         if (IS_ERR_OR_NULL(info_linear)) {
 534                 pr_debug("%s: failed to get BPF program info. aborting\n", __func__);
 535                 goto out;
 536         }
 537
 538         btf_id = info_linear->info.btf_id;
 539
 540         info_node = malloc(sizeof(struct bpf_prog_info_node));
 541         if (info_node) {
 542                 info_node->info_linear = info_linear;
 543                 perf_env__insert_bpf_prog_info(env, info_node);
 544         } else
 545                 free(info_linear);
 546
 547         if (btf_id == 0)
 548                 goto out;
 549
 550         btf = btf__load_from_kernel_by_id(btf_id);
 551         if (libbpf_get_error(btf)) {
 552                 pr_debug("%s: failed to get BTF of id %u, aborting\n",
 553                          __func__, btf_id);
 554                 goto out;
 555         }
 556         perf_env__fetch_btf(env, btf_id, btf);
 557
 558 out:
 559         btf__free(btf);
 560         close(fd);
 561 }
 562
 563 static int bpf_event__sb_cb(union perf_event *event, void *data)
 564 {
 565         struct perf_env *env = data;
 566
 567         if (event->header.type != PERF_RECORD_BPF_EVENT)
 568                 return -1;
 569
 570         switch (event->bpf.type) {
 571         case PERF_BPF_EVENT_PROG_LOAD:
 572                 perf_env__add_bpf_info(env, event->bpf.id);
 573
 574         case PERF_BPF_EVENT_PROG_UNLOAD:
 575                 /*
 576                  * Do not free bpf_prog_info and btf of the program here,
 577                  * as annotation still need them. They will be freed at
 578                  * the end of the session.
 579                  */
 580                 break;
 581         default:
 582                 pr_debug("unexpected bpf event type of %d\n", event->bpf.type);
 583                 break;
 584         }
 585
 586         return 0;
 587 }
 588
 589 int evlist__add_bpf_sb_event(struct evlist *evlist, struct perf_env *env)
 590 {
 591         struct perf_event_attr attr = {
 592                 .type             = PERF_TYPE_SOFTWARE,
 593                 .config           = PERF_COUNT_SW_DUMMY,
 594                 .sample_id_all    = 1,
 595                 .watermark        = 1,
 596                 .bpf_event        = 1,
 597                 .size      = sizeof(attr), /* to capture ABI version */
 598         };
 599
 600         /*
 601          * Older gcc versions don't support designated initializers, like above,
 602          * for unnamed union members, such as the following:
 603          */
 604         attr.wakeup_watermark = 1;
 605
 606         return evlist__add_sb_event(evlist, &attr, bpf_event__sb_cb, env);
 607 }
 608
 609 void bpf_event__print_bpf_prog_info(struct bpf_prog_info *info,
 610                                     struct perf_env *env,
 611                                     FILE *fp)
 612 {
 613         __u32 *prog_lens = (__u32 *)(uintptr_t)(info->jited_func_lens);
 614         __u64 *prog_addrs = (__u64 *)(uintptr_t)(info->jited_ksyms);
 615         char name[KSYM_NAME_LEN];
 616         struct btf *btf = NULL;
 617         u32 sub_prog_cnt, i;
 618
 619         sub_prog_cnt = info->nr_jited_ksyms;
 620         if (sub_prog_cnt != info->nr_prog_tags ||
 621             sub_prog_cnt != info->nr_jited_func_lens)
 622                 return;
 623
 624         if (info->btf_id) {
 625                 struct btf_node *node;
 626
 627                 node = perf_env__find_btf(env, info->btf_id);
 628                 if (node)
 629                         btf = btf__new((__u8 *)(node->data),
 630                                        node->data_size);
 631         }
 632
 633         if (sub_prog_cnt == 1) {
 634                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, 0);
 635                 fprintf(fp, "# bpf_prog_info %u: %s addr 0x%llx size %u\n",
 636                         info->id, name, prog_addrs[0], prog_lens[0]);
 637                 goto out;
 638         }
 639
 640         fprintf(fp, "# bpf_prog_info %u:\n", info->id);
 641         for (i = 0; i < sub_prog_cnt; i++) {
 642                 synthesize_bpf_prog_name(name, KSYM_NAME_LEN, info, btf, i);
 643
 644                 fprintf(fp, "# \tsub_prog %u: %s addr 0x%llx size %u\n",
 645                         i, name, prog_addrs[i], prog_lens[i]);
 646         }
 647 out:
 648         btf__free(btf);
 649 }