1 // SPDX-License-Identifier: GPL-2.0 2 #include <errno.h> 3 #include <stdlib.h> 4 #include <stdio.h> 5 #include <string.h> 6 #include <linux/kernel.h> 7 #include <linux/zalloc.h> 8 #include "dso.h" 9 #include "session.h" 10 #include "thread.h" 11 #include "thread-stack.h" 12 #include "debug.h" 13 #include "namespaces.h" 14 #include "comm.h" 15 #include "map.h" 16 #include "symbol.h" 17 #include "unwind.h" 18 #include "callchain.h" 19 20 #include <api/fs/fs.h> 21 22 int thread__init_maps(struct thread *thread, struct machine *machine) 23 { 24 pid_t pid = thread->pid_; 25 26 if (pid == thread->tid || pid == -1) { 27 thread->maps = maps__new(machine); 28 } else { 29 struct thread *leader = __machine__findnew_thread(machine, pid, pid); 30 if (leader) { 31 thread->maps = maps__get(leader->maps); 32 thread__put(leader); 33 } 34 } 35 36 return thread->maps ? 0 : -1; 37 } 38 39 struct thread *thread__new(pid_t pid, pid_t tid) 40 { 41 char *comm_str; 42 struct comm *comm; 43 struct thread *thread = zalloc(sizeof(*thread)); 44 45 if (thread != NULL) { 46 thread->pid_ = pid; 47 thread->tid = tid; 48 thread->ppid = -1; 49 thread->cpu = -1; 50 thread->guest_cpu = -1; 51 thread->lbr_stitch_enable = false; 52 INIT_LIST_HEAD(&thread->namespaces_list); 53 INIT_LIST_HEAD(&thread->comm_list); 54 init_rwsem(&thread->namespaces_lock); 55 init_rwsem(&thread->comm_lock); 56 57 comm_str = malloc(32); 58 if (!comm_str) 59 goto err_thread; 60 61 snprintf(comm_str, 32, ":%d", tid); 62 comm = comm__new(comm_str, 0, false); 63 free(comm_str); 64 if (!comm) 65 goto err_thread; 66 67 list_add(&comm->list, &thread->comm_list); 68 refcount_set(&thread->refcnt, 1); 69 RB_CLEAR_NODE(&thread->rb_node); 70 /* Thread holds first ref to nsdata. */ 71 thread->nsinfo = nsinfo__new(pid); 72 srccode_state_init(&thread->srccode_state); 73 } 74 75 return thread; 76 77 err_thread: 78 free(thread); 79 return NULL; 80 } 81 82 void thread__delete(struct thread *thread) 83 { 84 struct namespaces *namespaces, *tmp_namespaces; 85 struct comm *comm, *tmp_comm; 86 87 BUG_ON(!RB_EMPTY_NODE(&thread->rb_node)); 88 89 thread_stack__free(thread); 90 91 if (thread->maps) { 92 maps__put(thread->maps); 93 thread->maps = NULL; 94 } 95 down_write(&thread->namespaces_lock); 96 list_for_each_entry_safe(namespaces, tmp_namespaces, 97 &thread->namespaces_list, list) { 98 list_del_init(&namespaces->list); 99 namespaces__free(namespaces); 100 } 101 up_write(&thread->namespaces_lock); 102 103 down_write(&thread->comm_lock); 104 list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) { 105 list_del_init(&comm->list); 106 comm__free(comm); 107 } 108 up_write(&thread->comm_lock); 109 110 nsinfo__zput(thread->nsinfo); 111 srccode_state_free(&thread->srccode_state); 112 113 exit_rwsem(&thread->namespaces_lock); 114 exit_rwsem(&thread->comm_lock); 115 thread__free_stitch_list(thread); 116 free(thread); 117 } 118 119 struct thread *thread__get(struct thread *thread) 120 { 121 if (thread) 122 refcount_inc(&thread->refcnt); 123 return thread; 124 } 125 126 void thread__put(struct thread *thread) 127 { 128 if (thread && refcount_dec_and_test(&thread->refcnt)) { 129 /* 130 * Remove it from the dead threads list, as last reference is 131 * gone, if it is in a dead threads list. 132 * 133 * We may not be there anymore if say, the machine where it was 134 * stored was already deleted, so we already removed it from 135 * the dead threads and some other piece of code still keeps a 136 * reference. 137 * 138 * This is what 'perf sched' does and finally drops it in 139 * perf_sched__lat(), where it calls perf_sched__read_events(), 140 * that processes the events by creating a session and deleting 141 * it, which ends up destroying the list heads for the dead 142 * threads, but before it does that it removes all threads from 143 * it using list_del_init(). 144 * 145 * So we need to check here if it is in a dead threads list and 146 * if so, remove it before finally deleting the thread, to avoid 147 * an use after free situation. 148 */ 149 if (!list_empty(&thread->node)) 150 list_del_init(&thread->node); 151 thread__delete(thread); 152 } 153 } 154 155 static struct namespaces *__thread__namespaces(const struct thread *thread) 156 { 157 if (list_empty(&thread->namespaces_list)) 158 return NULL; 159 160 return list_first_entry(&thread->namespaces_list, struct namespaces, list); 161 } 162 163 struct namespaces *thread__namespaces(struct thread *thread) 164 { 165 struct namespaces *ns; 166 167 down_read(&thread->namespaces_lock); 168 ns = __thread__namespaces(thread); 169 up_read(&thread->namespaces_lock); 170 171 return ns; 172 } 173 174 static int __thread__set_namespaces(struct thread *thread, u64 timestamp, 175 struct perf_record_namespaces *event) 176 { 177 struct namespaces *new, *curr = __thread__namespaces(thread); 178 179 new = namespaces__new(event); 180 if (!new) 181 return -ENOMEM; 182 183 list_add(&new->list, &thread->namespaces_list); 184 185 if (timestamp && curr) { 186 /* 187 * setns syscall must have changed few or all the namespaces 188 * of this thread. Update end time for the namespaces 189 * previously used. 190 */ 191 curr = list_next_entry(new, list); 192 curr->end_time = timestamp; 193 } 194 195 return 0; 196 } 197 198 int thread__set_namespaces(struct thread *thread, u64 timestamp, 199 struct perf_record_namespaces *event) 200 { 201 int ret; 202 203 down_write(&thread->namespaces_lock); 204 ret = __thread__set_namespaces(thread, timestamp, event); 205 up_write(&thread->namespaces_lock); 206 return ret; 207 } 208 209 struct comm *thread__comm(const struct thread *thread) 210 { 211 if (list_empty(&thread->comm_list)) 212 return NULL; 213 214 return list_first_entry(&thread->comm_list, struct comm, list); 215 } 216 217 struct comm *thread__exec_comm(const struct thread *thread) 218 { 219 struct comm *comm, *last = NULL, *second_last = NULL; 220 221 list_for_each_entry(comm, &thread->comm_list, list) { 222 if (comm->exec) 223 return comm; 224 second_last = last; 225 last = comm; 226 } 227 228 /* 229 * 'last' with no start time might be the parent's comm of a synthesized 230 * thread (created by processing a synthesized fork event). For a main 231 * thread, that is very probably wrong. Prefer a later comm to avoid 232 * that case. 233 */ 234 if (second_last && !last->start && thread->pid_ == thread->tid) 235 return second_last; 236 237 return last; 238 } 239 240 static int ____thread__set_comm(struct thread *thread, const char *str, 241 u64 timestamp, bool exec) 242 { 243 struct comm *new, *curr = thread__comm(thread); 244 245 /* Override the default :tid entry */ 246 if (!thread->comm_set) { 247 int err = comm__override(curr, str, timestamp, exec); 248 if (err) 249 return err; 250 } else { 251 new = comm__new(str, timestamp, exec); 252 if (!new) 253 return -ENOMEM; 254 list_add(&new->list, &thread->comm_list); 255 256 if (exec) 257 unwind__flush_access(thread->maps); 258 } 259 260 thread->comm_set = true; 261 262 return 0; 263 } 264 265 int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp, 266 bool exec) 267 { 268 int ret; 269 270 down_write(&thread->comm_lock); 271 ret = ____thread__set_comm(thread, str, timestamp, exec); 272 up_write(&thread->comm_lock); 273 return ret; 274 } 275 276 int thread__set_comm_from_proc(struct thread *thread) 277 { 278 char path[64]; 279 char *comm = NULL; 280 size_t sz; 281 int err = -1; 282 283 if (!(snprintf(path, sizeof(path), "%d/task/%d/comm", 284 thread->pid_, thread->tid) >= (int)sizeof(path)) && 285 procfs__read_str(path, &comm, &sz) == 0) { 286 comm[sz - 1] = '\0'; 287 err = thread__set_comm(thread, comm, 0); 288 } 289 290 return err; 291 } 292 293 static const char *__thread__comm_str(const struct thread *thread) 294 { 295 const struct comm *comm = thread__comm(thread); 296 297 if (!comm) 298 return NULL; 299 300 return comm__str(comm); 301 } 302 303 const char *thread__comm_str(struct thread *thread) 304 { 305 const char *str; 306 307 down_read(&thread->comm_lock); 308 str = __thread__comm_str(thread); 309 up_read(&thread->comm_lock); 310 311 return str; 312 } 313 314 static int __thread__comm_len(struct thread *thread, const char *comm) 315 { 316 if (!comm) 317 return 0; 318 thread->comm_len = strlen(comm); 319 320 return thread->comm_len; 321 } 322 323 /* CHECKME: it should probably better return the max comm len from its comm list */ 324 int thread__comm_len(struct thread *thread) 325 { 326 int comm_len = thread->comm_len; 327 328 if (!comm_len) { 329 const char *comm; 330 331 down_read(&thread->comm_lock); 332 comm = __thread__comm_str(thread); 333 comm_len = __thread__comm_len(thread, comm); 334 up_read(&thread->comm_lock); 335 } 336 337 return comm_len; 338 } 339 340 size_t thread__fprintf(struct thread *thread, FILE *fp) 341 { 342 return fprintf(fp, "Thread %d %s\n", thread->tid, thread__comm_str(thread)) + 343 maps__fprintf(thread->maps, fp); 344 } 345 346 int thread__insert_map(struct thread *thread, struct map *map) 347 { 348 int ret; 349 350 ret = unwind__prepare_access(thread->maps, map, NULL); 351 if (ret) 352 return ret; 353 354 maps__fixup_overlappings(thread->maps, map, stderr); 355 maps__insert(thread->maps, map); 356 357 return 0; 358 } 359 360 static int __thread__prepare_access(struct thread *thread) 361 { 362 bool initialized = false; 363 int err = 0; 364 struct maps *maps = thread->maps; 365 struct map *map; 366 367 down_read(&maps->lock); 368 369 maps__for_each_entry(maps, map) { 370 err = unwind__prepare_access(thread->maps, map, &initialized); 371 if (err || initialized) 372 break; 373 } 374 375 up_read(&maps->lock); 376 377 return err; 378 } 379 380 static int thread__prepare_access(struct thread *thread) 381 { 382 int err = 0; 383 384 if (dwarf_callchain_users) 385 err = __thread__prepare_access(thread); 386 387 return err; 388 } 389 390 static int thread__clone_maps(struct thread *thread, struct thread *parent, bool do_maps_clone) 391 { 392 /* This is new thread, we share map groups for process. */ 393 if (thread->pid_ == parent->pid_) 394 return thread__prepare_access(thread); 395 396 if (thread->maps == parent->maps) { 397 pr_debug("broken map groups on thread %d/%d parent %d/%d\n", 398 thread->pid_, thread->tid, parent->pid_, parent->tid); 399 return 0; 400 } 401 /* But this one is new process, copy maps. */ 402 return do_maps_clone ? maps__clone(thread, parent->maps) : 0; 403 } 404 405 int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp, bool do_maps_clone) 406 { 407 if (parent->comm_set) { 408 const char *comm = thread__comm_str(parent); 409 int err; 410 if (!comm) 411 return -ENOMEM; 412 err = thread__set_comm(thread, comm, timestamp); 413 if (err) 414 return err; 415 } 416 417 thread->ppid = parent->tid; 418 return thread__clone_maps(thread, parent, do_maps_clone); 419 } 420 421 void thread__find_cpumode_addr_location(struct thread *thread, u64 addr, 422 struct addr_location *al) 423 { 424 size_t i; 425 const u8 cpumodes[] = { 426 PERF_RECORD_MISC_USER, 427 PERF_RECORD_MISC_KERNEL, 428 PERF_RECORD_MISC_GUEST_USER, 429 PERF_RECORD_MISC_GUEST_KERNEL 430 }; 431 432 for (i = 0; i < ARRAY_SIZE(cpumodes); i++) { 433 thread__find_symbol(thread, cpumodes[i], addr, al); 434 if (al->map) 435 break; 436 } 437 } 438 439 struct thread *thread__main_thread(struct machine *machine, struct thread *thread) 440 { 441 if (thread->pid_ == thread->tid) 442 return thread__get(thread); 443 444 if (thread->pid_ == -1) 445 return NULL; 446 447 return machine__find_thread(machine, thread->pid_, thread->pid_); 448 } 449 450 int thread__memcpy(struct thread *thread, struct machine *machine, 451 void *buf, u64 ip, int len, bool *is64bit) 452 { 453 u8 cpumode = PERF_RECORD_MISC_USER; 454 struct addr_location al; 455 long offset; 456 457 if (machine__kernel_ip(machine, ip)) 458 cpumode = PERF_RECORD_MISC_KERNEL; 459 460 if (!thread__find_map(thread, cpumode, ip, &al) || !al.map->dso || 461 al.map->dso->data.status == DSO_DATA_STATUS_ERROR || 462 map__load(al.map) < 0) 463 return -1; 464 465 offset = al.map->map_ip(al.map, ip); 466 if (is64bit) 467 *is64bit = al.map->dso->is_64_bit; 468 469 return dso__data_read_offset(al.map->dso, machine, offset, buf, len); 470 } 471 472 void thread__free_stitch_list(struct thread *thread) 473 { 474 struct lbr_stitch *lbr_stitch = thread->lbr_stitch; 475 struct stitch_list *pos, *tmp; 476 477 if (!lbr_stitch) 478 return; 479 480 list_for_each_entry_safe(pos, tmp, &lbr_stitch->lists, node) { 481 list_del_init(&pos->node); 482 free(pos); 483 } 484 485 list_for_each_entry_safe(pos, tmp, &lbr_stitch->free_lists, node) { 486 list_del_init(&pos->node); 487 free(pos); 488 } 489 490 zfree(&lbr_stitch->prev_lbr_cursor); 491 zfree(&thread->lbr_stitch); 492 } 493