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