1 // SPDX-License-Identifier: GPL-2.0 2 #include <elf.h> 3 #include <errno.h> 4 #include <fcntl.h> 5 #include <stdlib.h> 6 #include <stdio.h> 7 #include <string.h> 8 #include <linux/kernel.h> 9 #include <linux/zalloc.h> 10 #include "dso.h" 11 #include "session.h" 12 #include "thread.h" 13 #include "thread-stack.h" 14 #include "debug.h" 15 #include "namespaces.h" 16 #include "comm.h" 17 #include "map.h" 18 #include "symbol.h" 19 #include "unwind.h" 20 #include "callchain.h" 21 #include "dwarf-regs.h" 22 23 #include <api/fs/fs.h> 24 25 int thread__init_maps(struct thread *thread, struct machine *machine) 26 { 27 pid_t pid = thread__pid(thread); 28 29 if (pid == thread__tid(thread) || pid == -1) { 30 thread__set_maps(thread, maps__new(machine)); 31 } else { 32 struct thread *leader = machine__findnew_thread(machine, pid, pid); 33 34 if (leader) { 35 thread__set_maps(thread, maps__get(thread__maps(leader))); 36 thread__put(leader); 37 } 38 } 39 40 return thread__maps(thread) ? 0 : -1; 41 } 42 43 struct thread *thread__new(pid_t pid, pid_t tid) 44 NO_THREAD_SAFETY_ANALYSIS /* Allocation/creation is inherently single threaded. */ 45 { 46 RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread)); 47 struct thread *thread; 48 49 if (ADD_RC_CHK(thread, _thread) != NULL) { 50 struct comm *comm; 51 char comm_str[32]; 52 53 thread__set_pid(thread, pid); 54 thread__set_tid(thread, tid); 55 thread__set_ppid(thread, -1); 56 thread__set_cpu(thread, -1); 57 thread__set_guest_cpu(thread, -1); 58 thread__set_e_machine(thread, EM_NONE); 59 thread__set_lbr_stitch_enable(thread, false); 60 INIT_LIST_HEAD(thread__namespaces_list(thread)); 61 INIT_LIST_HEAD(thread__comm_list(thread)); 62 init_rwsem(thread__namespaces_lock(thread)); 63 init_rwsem(thread__comm_lock(thread)); 64 65 snprintf(comm_str, sizeof(comm_str), ":%d", tid); 66 comm = comm__new(comm_str, 0, false); 67 if (!comm) 68 goto err_thread; 69 70 list_add(&comm->list, thread__comm_list(thread)); 71 refcount_set(thread__refcnt(thread), 1); 72 /* Thread holds first ref to nsdata. */ 73 RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid); 74 srccode_state_init(thread__srccode_state(thread)); 75 } 76 77 return thread; 78 79 err_thread: 80 thread__delete(thread); 81 return NULL; 82 } 83 84 static void (*thread__priv_destructor)(void *priv); 85 86 void thread__set_priv_destructor(void (*destructor)(void *priv)) 87 { 88 assert(thread__priv_destructor == NULL); 89 90 thread__priv_destructor = destructor; 91 } 92 93 void thread__delete(struct thread *thread) 94 { 95 struct namespaces *namespaces, *tmp_namespaces; 96 struct comm *comm, *tmp_comm; 97 98 thread_stack__free(thread); 99 100 if (thread__maps(thread)) { 101 maps__put(thread__maps(thread)); 102 thread__set_maps(thread, NULL); 103 } 104 down_write(thread__namespaces_lock(thread)); 105 list_for_each_entry_safe(namespaces, tmp_namespaces, 106 thread__namespaces_list(thread), list) { 107 list_del_init(&namespaces->list); 108 namespaces__free(namespaces); 109 } 110 up_write(thread__namespaces_lock(thread)); 111 112 down_write(thread__comm_lock(thread)); 113 list_for_each_entry_safe(comm, tmp_comm, thread__comm_list(thread), list) { 114 list_del_init(&comm->list); 115 comm__free(comm); 116 } 117 up_write(thread__comm_lock(thread)); 118 119 nsinfo__zput(RC_CHK_ACCESS(thread)->nsinfo); 120 srccode_state_free(thread__srccode_state(thread)); 121 122 exit_rwsem(thread__namespaces_lock(thread)); 123 exit_rwsem(thread__comm_lock(thread)); 124 thread__free_stitch_list(thread); 125 126 if (thread__priv_destructor) 127 thread__priv_destructor(thread__priv(thread)); 128 129 RC_CHK_FREE(thread); 130 } 131 132 struct thread *thread__get(struct thread *thread) 133 { 134 struct thread *result; 135 136 if (RC_CHK_GET(result, thread)) 137 refcount_inc(thread__refcnt(thread)); 138 139 return result; 140 } 141 142 void thread__put(struct thread *thread) 143 { 144 if (thread && refcount_dec_and_test(thread__refcnt(thread))) 145 thread__delete(thread); 146 else 147 RC_CHK_PUT(thread); 148 } 149 150 static struct namespaces *__thread__namespaces(struct thread *thread) 151 { 152 if (list_empty(thread__namespaces_list(thread))) 153 return NULL; 154 155 return list_first_entry(thread__namespaces_list(thread), struct namespaces, list); 156 } 157 158 struct namespaces *thread__namespaces(struct thread *thread) 159 { 160 struct namespaces *ns; 161 162 down_read(thread__namespaces_lock(thread)); 163 ns = __thread__namespaces(thread); 164 up_read(thread__namespaces_lock(thread)); 165 166 return ns; 167 } 168 169 static int __thread__set_namespaces(struct thread *thread, u64 timestamp, 170 struct perf_record_namespaces *event) 171 { 172 struct namespaces *new, *curr = __thread__namespaces(thread); 173 174 new = namespaces__new(event); 175 if (!new) 176 return -ENOMEM; 177 178 list_add(&new->list, thread__namespaces_list(thread)); 179 180 if (timestamp && curr) { 181 /* 182 * setns syscall must have changed few or all the namespaces 183 * of this thread. Update end time for the namespaces 184 * previously used. 185 */ 186 curr = list_next_entry(new, list); 187 curr->end_time = timestamp; 188 } 189 190 return 0; 191 } 192 193 int thread__set_namespaces(struct thread *thread, u64 timestamp, 194 struct perf_record_namespaces *event) 195 { 196 int ret; 197 198 down_write(thread__namespaces_lock(thread)); 199 ret = __thread__set_namespaces(thread, timestamp, event); 200 up_write(thread__namespaces_lock(thread)); 201 return ret; 202 } 203 204 static struct comm *__thread__comm(struct thread *thread) 205 SHARED_LOCKS_REQUIRED(thread__comm_lock(thread)) 206 { 207 if (list_empty(thread__comm_list(thread))) 208 return NULL; 209 210 return list_first_entry(thread__comm_list(thread), struct comm, list); 211 } 212 213 struct comm *thread__comm(struct thread *thread) 214 { 215 struct comm *res = NULL; 216 217 down_read(thread__comm_lock(thread)); 218 res = __thread__comm(thread); 219 up_read(thread__comm_lock(thread)); 220 return res; 221 } 222 223 struct comm *thread__exec_comm(struct thread *thread) 224 { 225 struct comm *comm, *last = NULL, *second_last = NULL; 226 227 down_read(thread__comm_lock(thread)); 228 list_for_each_entry(comm, thread__comm_list(thread), list) { 229 if (comm->exec) { 230 up_read(thread__comm_lock(thread)); 231 return comm; 232 } 233 second_last = last; 234 last = comm; 235 } 236 up_read(thread__comm_lock(thread)); 237 238 /* 239 * 'last' with no start time might be the parent's comm of a synthesized 240 * thread (created by processing a synthesized fork event). For a main 241 * thread, that is very probably wrong. Prefer a later comm to avoid 242 * that case. 243 */ 244 if (second_last && !last->start && thread__pid(thread) == thread__tid(thread)) 245 return second_last; 246 247 return last; 248 } 249 250 static int ____thread__set_comm(struct thread *thread, const char *str, 251 u64 timestamp, bool exec) 252 EXCLUSIVE_LOCKS_REQUIRED(thread__comm_lock(thread)) 253 { 254 struct comm *new, *curr = __thread__comm(thread); 255 256 /* Override the default :tid entry */ 257 if (!thread__comm_set(thread)) { 258 int err = comm__override(curr, str, timestamp, exec); 259 if (err) 260 return err; 261 } else { 262 new = comm__new(str, timestamp, exec); 263 if (!new) 264 return -ENOMEM; 265 list_add(&new->list, thread__comm_list(thread)); 266 267 if (exec) 268 unwind__flush_access(thread__maps(thread)); 269 } 270 271 thread__set_comm_set(thread, true); 272 273 return 0; 274 } 275 276 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp, 277 bool exec) 278 { 279 int ret; 280 281 down_write(thread__comm_lock(thread)); 282 ret = ____thread__set_comm(thread, str, timestamp, exec); 283 up_write(thread__comm_lock(thread)); 284 return ret; 285 } 286 287 int thread__set_comm_from_proc(struct thread *thread) 288 { 289 char path[64]; 290 char *comm = NULL; 291 size_t sz; 292 int err = -1; 293 294 if (!(snprintf(path, sizeof(path), "%d/task/%d/comm", 295 thread__pid(thread), thread__tid(thread)) >= (int)sizeof(path)) && 296 procfs__read_str(path, &comm, &sz) == 0) { 297 comm[sz - 1] = '\0'; 298 err = thread__set_comm(thread, comm, 0); 299 } 300 301 return err; 302 } 303 304 static const char *__thread__comm_str(struct thread *thread) 305 SHARED_LOCKS_REQUIRED(thread__comm_lock(thread)) 306 { 307 const struct comm *comm = __thread__comm(thread); 308 309 if (!comm) 310 return NULL; 311 312 return comm__str(comm); 313 } 314 315 const char *thread__comm_str(struct thread *thread) 316 { 317 const char *str; 318 319 down_read(thread__comm_lock(thread)); 320 str = __thread__comm_str(thread); 321 up_read(thread__comm_lock(thread)); 322 323 return str; 324 } 325 326 static int __thread__comm_len(struct thread *thread, const char *comm) 327 { 328 if (!comm) 329 return 0; 330 thread__set_comm_len(thread, strlen(comm)); 331 332 return thread__var_comm_len(thread); 333 } 334 335 /* CHECKME: it should probably better return the max comm len from its comm list */ 336 int thread__comm_len(struct thread *thread) 337 { 338 int comm_len = thread__var_comm_len(thread); 339 340 if (!comm_len) { 341 const char *comm; 342 343 down_read(thread__comm_lock(thread)); 344 comm = __thread__comm_str(thread); 345 comm_len = __thread__comm_len(thread, comm); 346 up_read(thread__comm_lock(thread)); 347 } 348 349 return comm_len; 350 } 351 352 size_t thread__fprintf(struct thread *thread, FILE *fp) 353 { 354 return fprintf(fp, "Thread %d %s\n", thread__tid(thread), thread__comm_str(thread)) + 355 maps__fprintf(thread__maps(thread), fp); 356 } 357 358 int thread__insert_map(struct thread *thread, struct map *map) 359 { 360 int ret; 361 uint16_t e_machine; 362 363 ret = maps__fixup_overlap_and_insert(thread__maps(thread), map); 364 if (ret) 365 return ret; 366 367 e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL); 368 return unwind__prepare_access(thread__maps(thread), e_machine); 369 } 370 371 static int thread__prepare_access(struct thread *thread) 372 { 373 uint16_t e_machine = thread__e_machine(thread, /*machine=*/NULL, /*e_flags=*/NULL); 374 375 return unwind__prepare_access(thread__maps(thread), e_machine); 376 } 377 378 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone) 379 { 380 /* This is new thread, we share map groups for process. */ 381 if (thread__pid(thread) == thread__pid(parent)) 382 return thread__prepare_access(thread); 383 384 if (maps__equal(thread__maps(thread), thread__maps(parent))) { 385 pr_debug("broken map groups on thread %d/%d parent %d/%d\n", 386 thread__pid(thread), thread__tid(thread), 387 thread__pid(parent), thread__tid(parent)); 388 return 0; 389 } 390 /* But this one is new process, copy maps. */ 391 return do_maps_clone ? maps__copy_from(thread__maps(thread), thread__maps(parent)) : 0; 392 } 393 394 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone) 395 { 396 if (thread__comm_set(parent)) { 397 const char *comm = thread__comm_str(parent); 398 int err; 399 if (!comm) 400 return -ENOMEM; 401 err = thread__set_comm(thread, comm, timestamp); 402 if (err) 403 return err; 404 } 405 406 thread__set_ppid(thread, thread__tid(parent)); 407 return thread__clone_maps(thread, parent, do_maps_clone); 408 } 409 410 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr, 411 bool symbols, struct addr_location *al) 412 { 413 size_t i; 414 const u8 cpumodes[] = { 415 PERF_RECORD_MISC_USER, 416 PERF_RECORD_MISC_KERNEL, 417 PERF_RECORD_MISC_GUEST_USER, 418 PERF_RECORD_MISC_GUEST_KERNEL 419 }; 420 421 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) { 422 if (symbols) 423 thread__find_symbol(thread, cpumodes[i], addr, al); 424 else 425 thread__find_map(thread, cpumodes[i], addr, al); 426 427 if (al->map) 428 break; 429 } 430 } 431 432 static uint16_t read_proc_e_machine_for_pid(pid_t pid, uint32_t *e_flags) 433 { 434 char path[6 /* "/proc/" */ + 11 /* max length of pid */ + 5 /* "/exe\0" */]; 435 int fd; 436 uint16_t e_machine = EM_NONE; 437 438 snprintf(path, sizeof(path), "/proc/%d/exe", pid); 439 fd = open(path, O_RDONLY); 440 if (fd >= 0) { 441 e_machine = dso__read_e_machine(/*optional_dso=*/NULL, fd, e_flags); 442 close(fd); 443 } 444 return e_machine; 445 } 446 447 struct thread__e_machine_callback_args { 448 struct machine *machine; 449 uint32_t e_flags; 450 uint16_t e_machine; 451 }; 452 453 static int thread__e_machine_callback(struct map *map, void *_args) 454 { 455 struct thread__e_machine_callback_args *args = _args; 456 struct dso *dso = map__dso(map); 457 458 if (!dso) 459 return 0; // No dso, continue search. 460 461 args->e_machine = dso__e_machine(dso, args->machine, &args->e_flags); 462 return args->e_machine != EM_NONE ? 1 /* stop search */ : 0 /* continue search */; 463 } 464 465 uint16_t thread__e_machine(struct thread *thread, struct machine *machine, uint32_t *e_flags) 466 { 467 pid_t tid, pid; 468 uint16_t e_machine = RC_CHK_ACCESS(thread)->e_machine; 469 uint32_t local_e_flags = 0; 470 struct thread__e_machine_callback_args args = { 471 .machine = machine, 472 .e_flags = 0, 473 .e_machine = EM_NONE, 474 }; 475 476 if (e_machine != EM_NONE) { 477 if (e_flags) 478 *e_flags = thread__e_flags(thread); 479 return e_machine; 480 } 481 482 if (machine == NULL) { 483 struct maps *maps = thread__maps(thread); 484 485 machine = maps__machine(maps); 486 } 487 tid = thread__tid(thread); 488 pid = thread__pid(thread); 489 if (pid != tid) { 490 struct thread *parent = machine__findnew_thread(machine, pid, pid); 491 492 if (parent) { 493 e_machine = thread__e_machine(parent, machine, &local_e_flags); 494 thread__put(parent); 495 goto out; 496 } 497 /* Something went wrong, fallback. */ 498 } 499 /* Reading on the PID thread. First try to find from the maps. */ 500 maps__for_each_map(thread__maps(thread), thread__e_machine_callback, &args); 501 502 if (args.e_machine != EM_NONE) { 503 e_machine = args.e_machine; 504 local_e_flags = args.e_flags; 505 } else { 506 /* Maps failed, perhaps we're live with map events disabled. */ 507 bool is_live = machine->machines == NULL; 508 509 if (!is_live) { 510 /* Check if the session has a data file. */ 511 struct perf_session *session = container_of(machine->machines, 512 struct perf_session, 513 machines); 514 515 is_live = !!session->data; 516 } 517 /* Read from /proc/pid/exe if live. */ 518 if (is_live) 519 e_machine = read_proc_e_machine_for_pid(pid, &local_e_flags); 520 } 521 out: 522 if (e_machine != EM_NONE) { 523 thread__set_e_machine(thread, e_machine); 524 thread__set_e_flags(thread, local_e_flags); 525 } else { 526 e_machine = EM_HOST; 527 local_e_flags = EF_HOST; 528 } 529 if (e_flags) 530 *e_flags = local_e_flags; 531 return e_machine; 532 } 533 534 struct thread *thread__main_thread(struct machine *machine, struct thread *thread) 535 { 536 if (thread__pid(thread) == thread__tid(thread)) 537 return thread__get(thread); 538 539 if (thread__pid(thread) == -1) 540 return NULL; 541 542 return machine__find_thread(machine, thread__pid(thread), thread__pid(thread)); 543 } 544 545 int thread__memcpy(struct thread *thread, struct machine *machine, 546 void *buf, u64 ip, int len, bool *is64bit) 547 { 548 u8 cpumode = PERF_RECORD_MISC_USER; 549 struct addr_location al; 550 struct dso *dso; 551 long offset; 552 553 if (machine__kernel_ip(machine, ip)) 554 cpumode = PERF_RECORD_MISC_KERNEL; 555 556 addr_location__init(&al); 557 if (!thread__find_map(thread, cpumode, ip, &al)) { 558 addr_location__exit(&al); 559 return -1; 560 } 561 562 dso = map__dso(al.map); 563 564 if (!dso || dso__data(dso)->status == DSO_DATA_STATUS_ERROR || map__load(al.map) < 0) { 565 addr_location__exit(&al); 566 return -1; 567 } 568 569 offset = map__map_ip(al.map, ip); 570 if (is64bit) 571 *is64bit = dso__is_64_bit(dso); 572 573 addr_location__exit(&al); 574 575 return dso__data_read_offset(dso, machine, offset, buf, len); 576 } 577 578 void thread__free_stitch_list(struct thread *thread) 579 { 580 struct lbr_stitch *lbr_stitch = thread__lbr_stitch(thread); 581 struct stitch_list *pos, *tmp; 582 583 if (!lbr_stitch) 584 return; 585 586 list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) { 587 map_symbol__exit(&pos->cursor.ms); 588 list_del_init(&pos->node); 589 free(pos); 590 } 591 592 list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) { 593 list_del_init(&pos->node); 594 free(pos); 595 } 596 597 for (unsigned int i = 0 ; i < lbr_stitch->prev_lbr_cursor_size; i++) 598 map_symbol__exit(&lbr_stitch->prev_lbr_cursor[i].ms); 599 600 zfree(&lbr_stitch->prev_lbr_cursor); 601 free(thread__lbr_stitch(thread)); 602 thread__set_lbr_stitch(thread, NULL); 603 } 604