| 1 | |
| 2 | |
| 3 | * linux/kernel/exit.c
|
| 4 | *
|
| 5 | * Copyright (C) 1991, 1992 Linus Torvalds
|
| 6 |
|
| 7 |
|
| 8 | #include <linux/mm.h>
|
| 9 | #include <linux/slab.h>
|
| 10 | #include <linux/sched/autogroup.h>
|
| 11 | #include <linux/sched/mm.h>
|
| 12 | #include <linux/sched/stat.h>
|
| 13 | #include <linux/sched/task.h>
|
| 14 | #include <linux/sched/task_stack.h>
|
| 15 | #include <linux/sched/cputime.h>
|
| 16 | #include <linux/interrupt.h>
|
| 17 | #include <linux/module.h>
|
| 18 | #include <linux/capability.h>
|
| 19 | #include <linux/completion.h>
|
| 20 | #include <linux/personality.h>
|
| 21 | #include <linux/tty.h>
|
| 22 | #include <linux/iocontext.h>
|
| 23 | #include <linux/key.h>
|
| 24 | #include <linux/cpu.h>
|
| 25 | #include <linux/acct.h>
|
| 26 | #include <linux/tsacct_kern.h>
|
| 27 | #include <linux/file.h>
|
| 28 | #include <linux/fdtable.h>
|
| 29 | #include <linux/freezer.h>
|
| 30 | #include <linux/binfmts.h>
|
| 31 | #include <linux/nsproxy.h>
|
| 32 | #include <linux/pid_namespace.h>
|
| 33 | #include <linux/ptrace.h>
|
| 34 | #include <linux/profile.h>
|
| 35 | #include <linux/mount.h>
|
| 36 | #include <linux/proc_fs.h>
|
| 37 | #include <linux/kthread.h>
|
| 38 | #include <linux/mempolicy.h>
|
| 39 | #include <linux/taskstats_kern.h>
|
| 40 | #include <linux/delayacct.h>
|
| 41 | #include <linux/cgroup.h>
|
| 42 | #include <linux/syscalls.h>
|
| 43 | #include <linux/signal.h>
|
| 44 | #include <linux/posix-timers.h>
|
| 45 | #include <linux/cn_proc.h>
|
| 46 | #include <linux/mutex.h>
|
| 47 | #include <linux/futex.h>
|
| 48 | #include <linux/pipe_fs_i.h>
|
| 49 | #include <linux/audit.h>
|
| 50 | #include <linux/resource.h>
|
| 51 | #include <linux/task_io_accounting_ops.h>
|
| 52 | #include <linux/blkdev.h>
|
| 53 | #include <linux/task_work.h>
|
| 54 | #include <linux/fs_struct.h>
|
| 55 | #include <linux/init_task.h>
|
| 56 | #include <linux/perf_event.h>
|
| 57 | #include <trace/events/sched.h>
|
| 58 | #include <linux/hw_breakpoint.h>
|
| 59 | #include <linux/oom.h>
|
| 60 | #include <linux/writeback.h>
|
| 61 | #include <linux/shm.h>
|
| 62 | #include <linux/kcov.h>
|
| 63 | #include <linux/kmsan.h>
|
| 64 | #include <linux/random.h>
|
| 65 | #include <linux/rcuwait.h>
|
| 66 | #include <linux/compat.h>
|
| 67 | #include <linux/io_uring.h>
|
| 68 | #include <linux/kprobes.h>
|
| 69 | #include <linux/rethook.h>
|
| 70 | #include <linux/sysfs.h>
|
| 71 |
|
| 72 | #include <linux/uaccess.h>
|
| 73 | #include <asm/unistd.h>
|
| 74 | #include <asm/mmu_context.h>
|
| 75 |
|
| 76 | |
| 77 | * The default value should be high enough to not crash a system that randomly
|
| 78 | * crashes its kernel from time to time, but low enough to at least not permit
|
| 79 | * overflowing 32-bit refcounts or the ldsem writer count.
|
| 80 |
|
| 81 | static unsigned int oops_limit = 10000;
|
| 82 |
|
| 83 | #ifdef CONFIG_SYSCTL
|
| 84 | static struct ctl_table kern_exit_table[] = {
|
| 85 | {
|
| 86 | .procname = "oops_limit",
|
| 87 | .data = &oops_limit,
|
| 88 | .maxlen = sizeof(oops_limit),
|
| 89 | .mode = 0644,
|
| 90 | .proc_handler = proc_douintvec,
|
| 91 | },
|
| 92 | { }
|
| 93 | };
|
| 94 |
|
| 95 | static __init int kernel_exit_sysctls_init(void)
|
| 96 | {
|
| 97 | register_sysctl_init("kernel", kern_exit_table);
|
| 98 | return 0;
|
| 99 | }
|
| 100 | late_initcall(kernel_exit_sysctls_init);
|
| 101 | #endif
|
| 102 |
|
| 103 | static atomic_t oops_count = ATOMIC_INIT(0);
|
| 104 |
|
| 105 | #ifdef CONFIG_SYSFS
|
| 106 | static ssize_t oops_count_show(struct kobject *kobj, struct kobj_attribute *attr,
|
| 107 | char *page)
|
| 108 | {
|
| 109 | return sysfs_emit(page, "%d\n", atomic_read(&oops_count));
|
| 110 | }
|
| 111 |
|
| 112 | static struct kobj_attribute oops_count_attr = __ATTR_RO(oops_count);
|
| 113 |
|
| 114 | static __init int kernel_exit_sysfs_init(void)
|
| 115 | {
|
| 116 | sysfs_add_file_to_group(kernel_kobj, &oops_count_attr.attr, NULL);
|
| 117 | return 0;
|
| 118 | }
|
| 119 | late_initcall(kernel_exit_sysfs_init);
|
| 120 | #endif
|
| 121 |
|
| 122 | static void __unhash_process(struct task_struct *p, bool group_dead)
|
| 123 | {
|
| 124 | nr_threads--;
|
| 125 | detach_pid(p, PIDTYPE_PID);
|
| 126 | if (group_dead) {
|
| 127 | detach_pid(p, PIDTYPE_TGID);
|
| 128 | detach_pid(p, PIDTYPE_PGID);
|
| 129 | detach_pid(p, PIDTYPE_SID);
|
| 130 |
|
| 131 | list_del_rcu(&p->tasks);
|
| 132 | list_del_init(&p->sibling);
|
| 133 | __this_cpu_dec(process_counts);
|
| 134 | }
|
| 135 | list_del_rcu(&p->thread_group);
|
| 136 | list_del_rcu(&p->thread_node);
|
| 137 | }
|
| 138 |
|
| 139 | |
| 140 | * This function expects the tasklist_lock write-locked.
|
| 141 |
|
| 142 | static void __exit_signal(struct task_struct *tsk)
|
| 143 | {
|
| 144 | struct signal_struct *sig = tsk->signal;
|
| 145 | bool group_dead = thread_group_leader(tsk);
|
| 146 | struct sighand_struct *sighand;
|
| 147 | struct tty_struct *tty;
|
| 148 | u64 utime, stime;
|
| 149 |
|
| 150 | sighand = rcu_dereference_check(tsk->sighand,
|
| 151 | lockdep_tasklist_lock_is_held());
|
| 152 | spin_lock(&sighand->siglock);
|
| 153 |
|
| 154 | #ifdef CONFIG_POSIX_TIMERS
|
| 155 | posix_cpu_timers_exit(tsk);
|
| 156 | if (group_dead)
|
| 157 | posix_cpu_timers_exit_group(tsk);
|
| 158 | #endif
|
| 159 |
|
| 160 | if (group_dead) {
|
| 161 | tty = sig->tty;
|
| 162 | sig->tty = NULL;
|
| 163 | } else {
|
| 164 | |
| 165 | * If there is any task waiting for the group exit
|
| 166 | * then notify it:
|
| 167 |
|
| 168 | if (sig->notify_count > 0 && !--sig->notify_count)
|
| 169 | wake_up_process(sig->group_exec_task);
|
| 170 |
|
| 171 | if (tsk == sig->curr_target)
|
| 172 | sig->curr_target = next_thread(tsk);
|
| 173 | }
|
| 174 |
|
| 175 | add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
|
| 176 | sizeof(unsigned long long));
|
| 177 |
|
| 178 | |
| 179 | * Accumulate here the counters for all threads as they die. We could
|
| 180 | * skip the group leader because it is the last user of signal_struct,
|
| 181 | * but we want to avoid the race with thread_group_cputime() which can
|
| 182 | * see the empty ->thread_head list.
|
| 183 |
|
| 184 | task_cputime(tsk, &utime, &stime);
|
| 185 | write_seqlock(&sig->stats_lock);
|
| 186 | sig->utime += utime;
|
| 187 | sig->stime += stime;
|
| 188 | sig->gtime += task_gtime(tsk);
|
| 189 | sig->min_flt += tsk->min_flt;
|
| 190 | sig->maj_flt += tsk->maj_flt;
|
| 191 | sig->nvcsw += tsk->nvcsw;
|
| 192 | sig->nivcsw += tsk->nivcsw;
|
| 193 | sig->inblock += task_io_get_inblock(tsk);
|
| 194 | sig->oublock += task_io_get_oublock(tsk);
|
| 195 | task_io_accounting_add(&sig->ioac, &tsk->ioac);
|
| 196 | sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
|
| 197 | sig->nr_threads--;
|
| 198 | __unhash_process(tsk, group_dead);
|
| 199 | write_sequnlock(&sig->stats_lock);
|
| 200 |
|
| 201 | |
| 202 | * Do this under ->siglock, we can race with another thread
|
| 203 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
|
| 204 |
|
| 205 | flush_sigqueue(&tsk->pending);
|
| 206 | tsk->sighand = NULL;
|
| 207 | spin_unlock(&sighand->siglock);
|
| 208 |
|
| 209 | __cleanup_sighand(sighand);
|
| 210 | clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
|
| 211 | if (group_dead) {
|
| 212 | flush_sigqueue(&sig->shared_pending);
|
| 213 | tty_kref_put(tty);
|
| 214 | }
|
| 215 | }
|
| 216 |
|
| 217 | static void delayed_put_task_struct(struct rcu_head *rhp)
|
| 218 | {
|
| 219 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
|
| 220 |
|
| 221 | kprobe_flush_task(tsk);
|
| 222 | rethook_flush_task(tsk);
|
| 223 | perf_event_delayed_put(tsk);
|
| 224 | trace_sched_process_free(tsk);
|
| 225 | put_task_struct(tsk);
|
| 226 | }
|
| 227 |
|
| 228 | void put_task_struct_rcu_user(struct task_struct *task)
|
| 229 | {
|
| 230 | if (refcount_dec_and_test(&task->rcu_users))
|
| 231 | call_rcu(&task->rcu, delayed_put_task_struct);
|
| 232 | }
|
| 233 |
|
| 234 | void __weak release_thread(struct task_struct *dead_task)
|
| 235 | {
|
| 236 | }
|
| 237 |
|
| 238 | void release_task(struct task_struct *p)
|
| 239 | {
|
| 240 | struct task_struct *leader;
|
| 241 | struct pid *thread_pid;
|
| 242 | int zap_leader;
|
| 243 | repeat:
|
| 244 | |
| 245 | * can't be modifying its own credentials. But shut RCU-lockdep up
|
| 246 | rcu_read_lock();
|
| 247 | dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
|
| 248 | rcu_read_unlock();
|
| 249 |
|
| 250 | cgroup_release(p);
|
| 251 |
|
| 252 | write_lock_irq(&tasklist_lock);
|
| 253 | ptrace_release_task(p);
|
| 254 | thread_pid = get_pid(p->thread_pid);
|
| 255 | __exit_signal(p);
|
| 256 |
|
| 257 | |
| 258 | * If we are the last non-leader member of the thread
|
| 259 | * group, and the leader is zombie, then notify the
|
| 260 | * group leader's parent process. (if it wants notification.)
|
| 261 |
|
| 262 | zap_leader = 0;
|
| 263 | leader = p->group_leader;
|
| 264 | if (leader != p && thread_group_empty(leader)
|
| 265 | && leader->exit_state == EXIT_ZOMBIE) {
|
| 266 | |
| 267 | * If we were the last child thread and the leader has
|
| 268 | * exited already, and the leader's parent ignores SIGCHLD,
|
| 269 | * then we are the one who should release the leader.
|
| 270 |
|
| 271 | zap_leader = do_notify_parent(leader, leader->exit_signal);
|
| 272 | if (zap_leader)
|
| 273 | leader->exit_state = EXIT_DEAD;
|
| 274 | }
|
| 275 |
|
| 276 | write_unlock_irq(&tasklist_lock);
|
| 277 | seccomp_filter_release(p);
|
| 278 | proc_flush_pid(thread_pid);
|
| 279 | put_pid(thread_pid);
|
| 280 | release_thread(p);
|
| 281 | put_task_struct_rcu_user(p);
|
| 282 |
|
| 283 | p = leader;
|
| 284 | if (unlikely(zap_leader))
|
| 285 | goto repeat;
|
| 286 | }
|
| 287 |
|
| 288 | int rcuwait_wake_up(struct rcuwait *w)
|
| 289 | {
|
| 290 | int ret = 0;
|
| 291 | struct task_struct *task;
|
| 292 |
|
| 293 | rcu_read_lock();
|
| 294 |
|
| 295 | |
| 296 | * Order condition vs @task, such that everything prior to the load
|
| 297 | * of @task is visible. This is the condition as to why the user called
|
| 298 | * rcuwait_wake() in the first place. Pairs with set_current_state()
|
| 299 | * barrier (A) in rcuwait_wait_event().
|
| 300 | *
|
| 301 | * WAIT WAKE
|
| 302 | * [S] tsk = current [S] cond = true
|
| 303 | * MB (A) MB (B)
|
| 304 | * [L] cond [L] tsk
|
| 305 |
|
| 306 | smp_mb();
|
| 307 |
|
| 308 | task = rcu_dereference(w->task);
|
| 309 | if (task)
|
| 310 | ret = wake_up_process(task);
|
| 311 | rcu_read_unlock();
|
| 312 |
|
| 313 | return ret;
|
| 314 | }
|
| 315 | EXPORT_SYMBOL_GPL(rcuwait_wake_up);
|
| 316 |
|
| 317 | |
| 318 | * Determine if a process group is "orphaned", according to the POSIX
|
| 319 | * definition in 2.2.2.52. Orphaned process groups are not to be affected
|
| 320 | * by terminal-generated stop signals. Newly orphaned process groups are
|
| 321 | * to receive a SIGHUP and a SIGCONT.
|
| 322 | *
|
| 323 | * "I ask you, have you ever known what it is to be an orphan?"
|
| 324 |
|
| 325 | static int will_become_orphaned_pgrp(struct pid *pgrp,
|
| 326 | struct task_struct *ignored_task)
|
| 327 | {
|
| 328 | struct task_struct *p;
|
| 329 |
|
| 330 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
|
| 331 | if ((p == ignored_task) ||
|
| 332 | (p->exit_state && thread_group_empty(p)) ||
|
| 333 | is_global_init(p->real_parent))
|
| 334 | continue;
|
| 335 |
|
| 336 | if (task_pgrp(p->real_parent) != pgrp &&
|
| 337 | task_session(p->real_parent) == task_session(p))
|
| 338 | return 0;
|
| 339 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
|
| 340 |
|
| 341 | return 1;
|
| 342 | }
|
| 343 |
|
| 344 | int is_current_pgrp_orphaned(void)
|
| 345 | {
|
| 346 | int retval;
|
| 347 |
|
| 348 | read_lock(&tasklist_lock);
|
| 349 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
|
| 350 | read_unlock(&tasklist_lock);
|
| 351 |
|
| 352 | return retval;
|
| 353 | }
|
| 354 |
|
| 355 | static bool has_stopped_jobs(struct pid *pgrp)
|
| 356 | {
|
| 357 | struct task_struct *p;
|
| 358 |
|
| 359 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
|
| 360 | if (p->signal->flags & SIGNAL_STOP_STOPPED)
|
| 361 | return true;
|
| 362 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
|
| 363 |
|
| 364 | return false;
|
| 365 | }
|
| 366 |
|
| 367 | |
| 368 | * Check to see if any process groups have become orphaned as
|
| 369 | * a result of our exiting, and if they have any stopped jobs,
|
| 370 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
|
| 371 |
|
| 372 | static void
|
| 373 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
|
| 374 | {
|
| 375 | struct pid *pgrp = task_pgrp(tsk);
|
| 376 | struct task_struct *ignored_task = tsk;
|
| 377 |
|
| 378 | if (!parent)
|
| 379 | |
| 380 | * we are and we were the only connection outside.
|
| 381 |
|
| 382 | parent = tsk->real_parent;
|
| 383 | else
|
| 384 | |
| 385 | * we are, and it was the only connection outside.
|
| 386 |
|
| 387 | ignored_task = NULL;
|
| 388 |
|
| 389 | if (task_pgrp(parent) != pgrp &&
|
| 390 | task_session(parent) == task_session(tsk) &&
|
| 391 | will_become_orphaned_pgrp(pgrp, ignored_task) &&
|
| 392 | has_stopped_jobs(pgrp)) {
|
| 393 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
|
| 394 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
|
| 395 | }
|
| 396 | }
|
| 397 |
|
| 398 | static void coredump_task_exit(struct task_struct *tsk)
|
| 399 | {
|
| 400 | struct core_state *core_state;
|
| 401 |
|
| 402 | |
| 403 | * Serialize with any possible pending coredump.
|
| 404 | * We must hold siglock around checking core_state
|
| 405 | * and setting PF_POSTCOREDUMP. The core-inducing thread
|
| 406 | * will increment ->nr_threads for each thread in the
|
| 407 | * group without PF_POSTCOREDUMP set.
|
| 408 |
|
| 409 | spin_lock_irq(&tsk->sighand->siglock);
|
| 410 | tsk->flags |= PF_POSTCOREDUMP;
|
| 411 | core_state = tsk->signal->core_state;
|
| 412 | spin_unlock_irq(&tsk->sighand->siglock);
|
| 413 | if (core_state) {
|
| 414 | struct core_thread self;
|
| 415 |
|
| 416 | self.task = current;
|
| 417 | if (self.task->flags & PF_SIGNALED)
|
| 418 | self.next = xchg(&core_state->dumper.next, &self);
|
| 419 | else
|
| 420 | self.task = NULL;
|
| 421 | |
| 422 | * Implies mb(), the result of xchg() must be visible
|
| 423 | * to core_state->dumper.
|
| 424 |
|
| 425 | if (atomic_dec_and_test(&core_state->nr_threads))
|
| 426 | complete(&core_state->startup);
|
| 427 |
|
| 428 | for (;;) {
|
| 429 | set_current_state(TASK_UNINTERRUPTIBLE|TASK_FREEZABLE);
|
| 430 | if (!self.task)
|
| 431 | break;
|
| 432 | schedule();
|
| 433 | }
|
| 434 | __set_current_state(TASK_RUNNING);
|
| 435 | }
|
| 436 | }
|
| 437 |
|
| 438 | #ifdef CONFIG_MEMCG
|
| 439 | |
| 440 | * A task is exiting. If it owned this mm, find a new owner for the mm.
|
| 441 |
|
| 442 | void mm_update_next_owner(struct mm_struct *mm)
|
| 443 | {
|
| 444 | struct task_struct *c, *g, *p = current;
|
| 445 |
|
| 446 | retry:
|
| 447 | |
| 448 | * If the exiting or execing task is not the owner, it's
|
| 449 | * someone else's problem.
|
| 450 |
|
| 451 | if (mm->owner != p)
|
| 452 | return;
|
| 453 | |
| 454 | * The current owner is exiting/execing and there are no other
|
| 455 | * candidates. Do not leave the mm pointing to a possibly
|
| 456 | * freed task structure.
|
| 457 |
|
| 458 | if (atomic_read(&mm->mm_users) <= 1) {
|
| 459 | WRITE_ONCE(mm->owner, NULL);
|
| 460 | return;
|
| 461 | }
|
| 462 |
|
| 463 | read_lock(&tasklist_lock);
|
| 464 | |
| 465 | * Search in the children
|
| 466 |
|
| 467 | list_for_each_entry(c, &p->children, sibling) {
|
| 468 | if (c->mm == mm)
|
| 469 | goto assign_new_owner;
|
| 470 | }
|
| 471 |
|
| 472 | |
| 473 | * Search in the siblings
|
| 474 |
|
| 475 | list_for_each_entry(c, &p->real_parent->children, sibling) {
|
| 476 | if (c->mm == mm)
|
| 477 | goto assign_new_owner;
|
| 478 | }
|
| 479 |
|
| 480 | |
| 481 | * Search through everything else, we should not get here often.
|
| 482 |
|
| 483 | for_each_process(g) {
|
| 484 | if (g->flags & PF_KTHREAD)
|
| 485 | continue;
|
| 486 | for_each_thread(g, c) {
|
| 487 | if (c->mm == mm)
|
| 488 | goto assign_new_owner;
|
| 489 | if (c->mm)
|
| 490 | break;
|
| 491 | }
|
| 492 | }
|
| 493 | read_unlock(&tasklist_lock);
|
| 494 | |
| 495 | * We found no owner yet mm_users > 1: this implies that we are
|
| 496 | * most likely racing with swapoff (try_to_unuse()) or /proc or
|
| 497 | * ptrace or page migration (get_task_mm()). Mark owner as NULL.
|
| 498 |
|
| 499 | WRITE_ONCE(mm->owner, NULL);
|
| 500 | return;
|
| 501 |
|
| 502 | assign_new_owner:
|
| 503 | BUG_ON(c == p);
|
| 504 | get_task_struct(c);
|
| 505 | |
| 506 | * The task_lock protects c->mm from changing.
|
| 507 | * We always want mm->owner->mm == mm
|
| 508 |
|
| 509 | task_lock(c);
|
| 510 | |
| 511 | * Delay read_unlock() till we have the task_lock()
|
| 512 | * to ensure that c does not slip away underneath us
|
| 513 |
|
| 514 | read_unlock(&tasklist_lock);
|
| 515 | if (c->mm != mm) {
|
| 516 | task_unlock(c);
|
| 517 | put_task_struct(c);
|
| 518 | goto retry;
|
| 519 | }
|
| 520 | WRITE_ONCE(mm->owner, c);
|
| 521 | lru_gen_migrate_mm(mm);
|
| 522 | task_unlock(c);
|
| 523 | put_task_struct(c);
|
| 524 | }
|
| 525 | #endif
|
| 526 |
|
| 527 | |
| 528 | * Turn us into a lazy TLB process if we
|
| 529 | * aren't already..
|
| 530 |
|
| 531 | static void exit_mm(void)
|
| 532 | {
|
| 533 | struct mm_struct *mm = current->mm;
|
| 534 |
|
| 535 | exit_mm_release(current, mm);
|
| 536 | if (!mm)
|
| 537 | return;
|
| 538 | sync_mm_rss(mm);
|
| 539 | mmap_read_lock(mm);
|
| 540 | mmgrab(mm);
|
| 541 | BUG_ON(mm != current->active_mm);
|
| 542 |
|
| 543 | task_lock(current);
|
| 544 | |
| 545 | * When a thread stops operating on an address space, the loop
|
| 546 | * in membarrier_private_expedited() may not observe that
|
| 547 | * tsk->mm, and the loop in membarrier_global_expedited() may
|
| 548 | * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
|
| 549 | * rq->membarrier_state, so those would not issue an IPI.
|
| 550 | * Membarrier requires a memory barrier after accessing
|
| 551 | * user-space memory, before clearing tsk->mm or the
|
| 552 | * rq->membarrier_state.
|
| 553 |
|
| 554 | smp_mb__after_spinlock();
|
| 555 | local_irq_disable();
|
| 556 | current->mm = NULL;
|
| 557 | membarrier_update_current_mm(NULL);
|
| 558 | enter_lazy_tlb(mm, current);
|
| 559 | local_irq_enable();
|
| 560 | task_unlock(current);
|
| 561 | mmap_read_unlock(mm);
|
| 562 | mm_update_next_owner(mm);
|
| 563 | mmput(mm);
|
| 564 | if (test_thread_flag(TIF_MEMDIE))
|
| 565 | exit_oom_victim();
|
| 566 | }
|
| 567 |
|
| 568 | static struct task_struct *find_alive_thread(struct task_struct *p)
|
| 569 | {
|
| 570 | struct task_struct *t;
|
| 571 |
|
| 572 | for_each_thread(p, t) {
|
| 573 | if (!(t->flags & PF_EXITING))
|
| 574 | return t;
|
| 575 | }
|
| 576 | return NULL;
|
| 577 | }
|
| 578 |
|
| 579 | static struct task_struct *find_child_reaper(struct task_struct *father,
|
| 580 | struct list_head *dead)
|
| 581 | __releases(&tasklist_lock)
|
| 582 | __acquires(&tasklist_lock)
|
| 583 | {
|
| 584 | struct pid_namespace *pid_ns = task_active_pid_ns(father);
|
| 585 | struct task_struct *reaper = pid_ns->child_reaper;
|
| 586 | struct task_struct *p, *n;
|
| 587 |
|
| 588 | if (likely(reaper != father))
|
| 589 | return reaper;
|
| 590 |
|
| 591 | reaper = find_alive_thread(father);
|
| 592 | if (reaper) {
|
| 593 | pid_ns->child_reaper = reaper;
|
| 594 | return reaper;
|
| 595 | }
|
| 596 |
|
| 597 | write_unlock_irq(&tasklist_lock);
|
| 598 |
|
| 599 | list_for_each_entry_safe(p, n, dead, ptrace_entry) {
|
| 600 | list_del_init(&p->ptrace_entry);
|
| 601 | release_task(p);
|
| 602 | }
|
| 603 |
|
| 604 | zap_pid_ns_processes(pid_ns);
|
| 605 | write_lock_irq(&tasklist_lock);
|
| 606 |
|
| 607 | return father;
|
| 608 | }
|
| 609 |
|
| 610 | |
| 611 | * When we die, we re-parent all our children, and try to:
|
| 612 | * 1. give them to another thread in our thread group, if such a member exists
|
| 613 | * 2. give it to the first ancestor process which prctl'd itself as a
|
| 614 | * child_subreaper for its children (like a service manager)
|
| 615 | * 3. give it to the init process (PID 1) in our pid namespace
|
| 616 |
|
| 617 | static struct task_struct *find_new_reaper(struct task_struct *father,
|
| 618 | struct task_struct *child_reaper)
|
| 619 | {
|
| 620 | struct task_struct *thread, *reaper;
|
| 621 |
|
| 622 | thread = find_alive_thread(father);
|
| 623 | if (thread)
|
| 624 | return thread;
|
| 625 |
|
| 626 | if (father->signal->has_child_subreaper) {
|
| 627 | unsigned int ns_level = task_pid(father)->level;
|
| 628 | |
| 629 | * Find the first ->is_child_subreaper ancestor in our pid_ns.
|
| 630 | * We can't check reaper != child_reaper to ensure we do not
|
| 631 | * cross the namespaces, the exiting parent could be injected
|
| 632 | * by setns() + fork().
|
| 633 | * We check pid->level, this is slightly more efficient than
|
| 634 | * task_active_pid_ns(reaper) != task_active_pid_ns(father).
|
| 635 |
|
| 636 | for (reaper = father->real_parent;
|
| 637 | task_pid(reaper)->level == ns_level;
|
| 638 | reaper = reaper->real_parent) {
|
| 639 | if (reaper == &init_task)
|
| 640 | break;
|
| 641 | if (!reaper->signal->is_child_subreaper)
|
| 642 | continue;
|
| 643 | thread = find_alive_thread(reaper);
|
| 644 | if (thread)
|
| 645 | return thread;
|
| 646 | }
|
| 647 | }
|
| 648 |
|
| 649 | return child_reaper;
|
| 650 | }
|
| 651 |
|
| 652 | |
| 653 | * Any that need to be release_task'd are put on the @dead list.
|
| 654 |
|
| 655 | static void reparent_leader(struct task_struct *father, struct task_struct *p,
|
| 656 | struct list_head *dead)
|
| 657 | {
|
| 658 | if (unlikely(p->exit_state == EXIT_DEAD))
|
| 659 | return;
|
| 660 |
|
| 661 |
|
| 662 | p->exit_signal = SIGCHLD;
|
| 663 |
|
| 664 |
|
| 665 | if (!p->ptrace &&
|
| 666 | p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
|
| 667 | if (do_notify_parent(p, p->exit_signal)) {
|
| 668 | p->exit_state = EXIT_DEAD;
|
| 669 | list_add(&p->ptrace_entry, dead);
|
| 670 | }
|
| 671 | }
|
| 672 |
|
| 673 | kill_orphaned_pgrp(p, father);
|
| 674 | }
|
| 675 |
|
| 676 | |
| 677 | * This does two things:
|
| 678 | *
|
| 679 | * A. Make init inherit all the child processes
|
| 680 | * B. Check to see if any process groups have become orphaned
|
| 681 | * as a result of our exiting, and if they have any stopped
|
| 682 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
|
| 683 |
|
| 684 | static void forget_original_parent(struct task_struct *father,
|
| 685 | struct list_head *dead)
|
| 686 | {
|
| 687 | struct task_struct *p, *t, *reaper;
|
| 688 |
|
| 689 | if (unlikely(!list_empty(&father->ptraced)))
|
| 690 | exit_ptrace(father, dead);
|
| 691 |
|
| 692 |
|
| 693 | reaper = find_child_reaper(father, dead);
|
| 694 | if (list_empty(&father->children))
|
| 695 | return;
|
| 696 |
|
| 697 | reaper = find_new_reaper(father, reaper);
|
| 698 | list_for_each_entry(p, &father->children, sibling) {
|
| 699 | for_each_thread(p, t) {
|
| 700 | RCU_INIT_POINTER(t->real_parent, reaper);
|
| 701 | BUG_ON((!t->ptrace) != (rcu_access_pointer(t->parent) == father));
|
| 702 | if (likely(!t->ptrace))
|
| 703 | t->parent = t->real_parent;
|
| 704 | if (t->pdeath_signal)
|
| 705 | group_send_sig_info(t->pdeath_signal,
|
| 706 | SEND_SIG_NOINFO, t,
|
| 707 | PIDTYPE_TGID);
|
| 708 | }
|
| 709 | |
| 710 | * If this is a threaded reparent there is no need to
|
| 711 | * notify anyone anything has happened.
|
| 712 |
|
| 713 | if (!same_thread_group(reaper, father))
|
| 714 | reparent_leader(father, p, dead);
|
| 715 | }
|
| 716 | list_splice_tail_init(&father->children, &reaper->children);
|
| 717 | }
|
| 718 |
|
| 719 | |
| 720 | * Send signals to all our closest relatives so that they know
|
| 721 | * to properly mourn us..
|
| 722 |
|
| 723 | static void exit_notify(struct task_struct *tsk, int group_dead)
|
| 724 | {
|
| 725 | bool autoreap;
|
| 726 | struct task_struct *p, *n;
|
| 727 | LIST_HEAD(dead);
|
| 728 |
|
| 729 | write_lock_irq(&tasklist_lock);
|
| 730 | forget_original_parent(tsk, &dead);
|
| 731 |
|
| 732 | if (group_dead)
|
| 733 | kill_orphaned_pgrp(tsk->group_leader, NULL);
|
| 734 |
|
| 735 | tsk->exit_state = EXIT_ZOMBIE;
|
| 736 | if (unlikely(tsk->ptrace)) {
|
| 737 | int sig = thread_group_leader(tsk) &&
|
| 738 | thread_group_empty(tsk) &&
|
| 739 | !ptrace_reparented(tsk) ?
|
| 740 | tsk->exit_signal : SIGCHLD;
|
| 741 | autoreap = do_notify_parent(tsk, sig);
|
| 742 | } else if (thread_group_leader(tsk)) {
|
| 743 | autoreap = thread_group_empty(tsk) &&
|
| 744 | do_notify_parent(tsk, tsk->exit_signal);
|
| 745 | } else {
|
| 746 | autoreap = true;
|
| 747 | }
|
| 748 |
|
| 749 | if (autoreap) {
|
| 750 | tsk->exit_state = EXIT_DEAD;
|
| 751 | list_add(&tsk->ptrace_entry, &dead);
|
| 752 | }
|
| 753 |
|
| 754 |
|
| 755 | if (unlikely(tsk->signal->notify_count < 0))
|
| 756 | wake_up_process(tsk->signal->group_exec_task);
|
| 757 | write_unlock_irq(&tasklist_lock);
|
| 758 |
|
| 759 | list_for_each_entry_safe(p, n, &dead, ptrace_entry) {
|
| 760 | list_del_init(&p->ptrace_entry);
|
| 761 | release_task(p);
|
| 762 | }
|
| 763 | }
|
| 764 |
|
| 765 | #ifdef CONFIG_DEBUG_STACK_USAGE
|
| 766 | static void check_stack_usage(void)
|
| 767 | {
|
| 768 | static DEFINE_SPINLOCK(low_water_lock);
|
| 769 | static int lowest_to_date = THREAD_SIZE;
|
| 770 | unsigned long free;
|
| 771 |
|
| 772 | free = stack_not_used(current);
|
| 773 |
|
| 774 | if (free >= lowest_to_date)
|
| 775 | return;
|
| 776 |
|
| 777 | spin_lock(&low_water_lock);
|
| 778 | if (free < lowest_to_date) {
|
| 779 | pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
|
| 780 | current->comm, task_pid_nr(current), free);
|
| 781 | lowest_to_date = free;
|
| 782 | }
|
| 783 | spin_unlock(&low_water_lock);
|
| 784 | }
|
| 785 | #else
|
| 786 | static inline void check_stack_usage(void) {}
|
| 787 | #endif
|
| 788 |
|
| 789 | static void synchronize_group_exit(struct task_struct *tsk, long code)
|
| 790 | {
|
| 791 | struct sighand_struct *sighand = tsk->sighand;
|
| 792 | struct signal_struct *signal = tsk->signal;
|
| 793 |
|
| 794 | spin_lock_irq(&sighand->siglock);
|
| 795 | signal->quick_threads--;
|
| 796 | if ((signal->quick_threads == 0) &&
|
| 797 | !(signal->flags & SIGNAL_GROUP_EXIT)) {
|
| 798 | signal->flags = SIGNAL_GROUP_EXIT;
|
| 799 | signal->group_exit_code = code;
|
| 800 | signal->group_stop_count = 0;
|
| 801 | }
|
| 802 | spin_unlock_irq(&sighand->siglock);
|
| 803 | }
|
| 804 |
|
| 805 | void __noreturn do_exit(long code)
|
| 806 | {
|
| 807 | struct task_struct *tsk = current;
|
| 808 | int group_dead;
|
| 809 |
|
| 810 | synchronize_group_exit(tsk, code);
|
| 811 |
|
| 812 | WARN_ON(tsk->plug);
|
| 813 |
|
| 814 | kcov_task_exit(tsk);
|
| 815 | kmsan_task_exit(tsk);
|
| 816 |
|
| 817 | coredump_task_exit(tsk);
|
| 818 | ptrace_event(PTRACE_EVENT_EXIT, code);
|
| 819 |
|
| 820 | validate_creds_for_do_exit(tsk);
|
| 821 |
|
| 822 | io_uring_files_cancel();
|
| 823 | exit_signals(tsk);
|
| 824 |
|
| 825 |
|
| 826 | if (tsk->mm)
|
| 827 | sync_mm_rss(tsk->mm);
|
| 828 | acct_update_integrals(tsk);
|
| 829 | group_dead = atomic_dec_and_test(&tsk->signal->live);
|
| 830 | if (group_dead) {
|
| 831 | |
| 832 | * If the last thread of global init has exited, panic
|
| 833 | * immediately to get a useable coredump.
|
| 834 |
|
| 835 | if (unlikely(is_global_init(tsk)))
|
| 836 | panic("Attempted to kill init! exitcode=0x%08x\n",
|
| 837 | tsk->signal->group_exit_code ?: (int)code);
|
| 838 |
|
| 839 | #ifdef CONFIG_POSIX_TIMERS
|
| 840 | hrtimer_cancel(&tsk->signal->real_timer);
|
| 841 | exit_itimers(tsk);
|
| 842 | #endif
|
| 843 | if (tsk->mm)
|
| 844 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
|
| 845 | }
|
| 846 | acct_collect(code, group_dead);
|
| 847 | if (group_dead)
|
| 848 | tty_audit_exit();
|
| 849 | audit_free(tsk);
|
| 850 |
|
| 851 | tsk->exit_code = code;
|
| 852 | taskstats_exit(tsk, group_dead);
|
| 853 |
|
| 854 | exit_mm();
|
| 855 |
|
| 856 | if (group_dead)
|
| 857 | acct_process();
|
| 858 | trace_sched_process_exit(tsk);
|
| 859 |
|
| 860 | exit_sem(tsk);
|
| 861 | exit_shm(tsk);
|
| 862 | exit_files(tsk);
|
| 863 | exit_fs(tsk);
|
| 864 | if (group_dead)
|
| 865 | disassociate_ctty(1);
|
| 866 | exit_task_namespaces(tsk);
|
| 867 | exit_task_work(tsk);
|
| 868 | exit_thread(tsk);
|
| 869 |
|
| 870 | |
| 871 | * Flush inherited counters to the parent - before the parent
|
| 872 | * gets woken up by child-exit notifications.
|
| 873 | *
|
| 874 | * because of cgroup mode, must be called before cgroup_exit()
|
| 875 |
|
| 876 | perf_event_exit_task(tsk);
|
| 877 |
|
| 878 | sched_autogroup_exit_task(tsk);
|
| 879 | cgroup_exit(tsk);
|
| 880 |
|
| 881 | |
| 882 | * FIXME: do that only when needed, using sched_exit tracepoint
|
| 883 |
|
| 884 | flush_ptrace_hw_breakpoint(tsk);
|
| 885 |
|
| 886 | exit_tasks_rcu_start();
|
| 887 | exit_notify(tsk, group_dead);
|
| 888 | proc_exit_connector(tsk);
|
| 889 | mpol_put_task_policy(tsk);
|
| 890 | #ifdef CONFIG_FUTEX
|
| 891 | if (unlikely(current->pi_state_cache))
|
| 892 | kfree(current->pi_state_cache);
|
| 893 | #endif
|
| 894 | |
| 895 | * Make sure we are holding no locks:
|
| 896 |
|
| 897 | debug_check_no_locks_held();
|
| 898 |
|
| 899 | if (tsk->io_context)
|
| 900 | exit_io_context(tsk);
|
| 901 |
|
| 902 | if (tsk->splice_pipe)
|
| 903 | free_pipe_info(tsk->splice_pipe);
|
| 904 |
|
| 905 | if (tsk->task_frag.page)
|
| 906 | put_page(tsk->task_frag.page);
|
| 907 |
|
| 908 | validate_creds_for_do_exit(tsk);
|
| 909 | exit_task_stack_account(tsk);
|
| 910 |
|
| 911 | check_stack_usage();
|
| 912 | preempt_disable();
|
| 913 | if (tsk->nr_dirtied)
|
| 914 | __this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
|
| 915 | exit_rcu();
|
| 916 | exit_tasks_rcu_finish();
|
| 917 |
|
| 918 | lockdep_free_task(tsk);
|
| 919 | do_task_dead();
|
| 920 | }
|
| 921 |
|
| 922 | void __noreturn make_task_dead(int signr)
|
| 923 | {
|
| 924 | |
| 925 | * Take the task off the cpu after something catastrophic has
|
| 926 | * happened.
|
| 927 | *
|
| 928 | * We can get here from a kernel oops, sometimes with preemption off.
|
| 929 | * Start by checking for critical errors.
|
| 930 | * Then fix up important state like USER_DS and preemption.
|
| 931 | * Then do everything else.
|
| 932 |
|
| 933 | struct task_struct *tsk = current;
|
| 934 | unsigned int limit;
|
| 935 |
|
| 936 | if (unlikely(in_interrupt()))
|
| 937 | panic("Aiee, killing interrupt handler!");
|
| 938 | if (unlikely(!tsk->pid))
|
| 939 | panic("Attempted to kill the idle task!");
|
| 940 |
|
| 941 | if (unlikely(in_atomic())) {
|
| 942 | pr_info("note: %s[%d] exited with preempt_count %d\n",
|
| 943 | current->comm, task_pid_nr(current),
|
| 944 | preempt_count());
|
| 945 | preempt_count_set(PREEMPT_ENABLED);
|
| 946 | }
|
| 947 |
|
| 948 | |
| 949 | * Every time the system oopses, if the oops happens while a reference
|
| 950 | * to an object was held, the reference leaks.
|
| 951 | * If the oops doesn't also leak memory, repeated oopsing can cause
|
| 952 | * reference counters to wrap around (if they're not using refcount_t).
|
| 953 | * This means that repeated oopsing can make unexploitable-looking bugs
|
| 954 | * exploitable through repeated oopsing.
|
| 955 | * To make sure this can't happen, place an upper bound on how often the
|
| 956 | * kernel may oops without panic().
|
| 957 |
|
| 958 | limit = READ_ONCE(oops_limit);
|
| 959 | if (atomic_inc_return(&oops_count) >= limit && limit)
|
| 960 | panic("Oopsed too often (kernel.oops_limit is %d)", limit);
|
| 961 |
|
| 962 | |
| 963 | * We're taking recursive faults here in make_task_dead. Safest is to just
|
| 964 | * leave this task alone and wait for reboot.
|
| 965 |
|
| 966 | if (unlikely(tsk->flags & PF_EXITING)) {
|
| 967 | pr_alert("Fixing recursive fault but reboot is needed!\n");
|
| 968 | futex_exit_recursive(tsk);
|
| 969 | tsk->exit_state = EXIT_DEAD;
|
| 970 | refcount_inc(&tsk->rcu_users);
|
| 971 | do_task_dead();
|
| 972 | }
|
| 973 |
|
| 974 | do_exit(signr);
|
| 975 | }
|
| 976 |
|
| 977 | SYSCALL_DEFINE1(exit, int, error_code)
|
| 978 | {
|
| 979 | do_exit((error_code&0xff)<<8);
|
| 980 | }
|
| 981 |
|
| 982 | |
| 983 | * Take down every thread in the group. This is called by fatal signals
|
| 984 | * as well as by sys_exit_group (below).
|
| 985 |
|
| 986 | void __noreturn
|
| 987 | do_group_exit(int exit_code)
|
| 988 | {
|
| 989 | struct signal_struct *sig = current->signal;
|
| 990 |
|
| 991 | if (sig->flags & SIGNAL_GROUP_EXIT)
|
| 992 | exit_code = sig->group_exit_code;
|
| 993 | else if (sig->group_exec_task)
|
| 994 | exit_code = 0;
|
| 995 | else {
|
| 996 | struct sighand_struct *const sighand = current->sighand;
|
| 997 |
|
| 998 | spin_lock_irq(&sighand->siglock);
|
| 999 | if (sig->flags & SIGNAL_GROUP_EXIT)
|
| 1000 |
|
| 1001 | exit_code = sig->group_exit_code;
|
| 1002 | else if (sig->group_exec_task)
|
| 1003 | exit_code = 0;
|
| 1004 | else {
|
| 1005 | sig->group_exit_code = exit_code;
|
| 1006 | sig->flags = SIGNAL_GROUP_EXIT;
|
| 1007 | zap_other_threads(current);
|
| 1008 | }
|
| 1009 | spin_unlock_irq(&sighand->siglock);
|
| 1010 | }
|
| 1011 |
|
| 1012 | do_exit(exit_code);
|
| 1013 |
|
| 1014 | }
|
| 1015 |
|
| 1016 | |
| 1017 | * this kills every thread in the thread group. Note that any externally
|
| 1018 | * wait4()-ing process will get the correct exit code - even if this
|
| 1019 | * thread is not the thread group leader.
|
| 1020 |
|
| 1021 | SYSCALL_DEFINE1(exit_group, int, error_code)
|
| 1022 | {
|
| 1023 | do_group_exit((error_code & 0xff) << 8);
|
| 1024 |
|
| 1025 | return 0;
|
| 1026 | }
|
| 1027 |
|
| 1028 | struct waitid_info {
|
| 1029 | pid_t pid;
|
| 1030 | uid_t uid;
|
| 1031 | int status;
|
| 1032 | int cause;
|
| 1033 | };
|
| 1034 |
|
| 1035 | struct wait_opts {
|
| 1036 | enum pid_type wo_type;
|
| 1037 | int wo_flags;
|
| 1038 | struct pid *wo_pid;
|
| 1039 |
|
| 1040 | struct waitid_info *wo_info;
|
| 1041 | int wo_stat;
|
| 1042 | struct rusage *wo_rusage;
|
| 1043 |
|
| 1044 | wait_queue_entry_t child_wait;
|
| 1045 | int notask_error;
|
| 1046 | };
|
| 1047 |
|
| 1048 | static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
|
| 1049 | {
|
| 1050 | return wo->wo_type == PIDTYPE_MAX ||
|
| 1051 | task_pid_type(p, wo->wo_type) == wo->wo_pid;
|
| 1052 | }
|
| 1053 |
|
| 1054 | static int
|
| 1055 | eligible_child(struct wait_opts *wo, bool ptrace, struct task_struct *p)
|
| 1056 | {
|
| 1057 | if (!eligible_pid(wo, p))
|
| 1058 | return 0;
|
| 1059 |
|
| 1060 | |
| 1061 | * Wait for all children (clone and not) if __WALL is set or
|
| 1062 | * if it is traced by us.
|
| 1063 |
|
| 1064 | if (ptrace || (wo->wo_flags & __WALL))
|
| 1065 | return 1;
|
| 1066 |
|
| 1067 | |
| 1068 | * Otherwise, wait for clone children *only* if __WCLONE is set;
|
| 1069 | * otherwise, wait for non-clone children *only*.
|
| 1070 | *
|
| 1071 | * Note: a "clone" child here is one that reports to its parent
|
| 1072 | * using a signal other than SIGCHLD, or a non-leader thread which
|
| 1073 | * we can only see if it is traced by us.
|
| 1074 |
|
| 1075 | if ((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
|
| 1076 | return 0;
|
| 1077 |
|
| 1078 | return 1;
|
| 1079 | }
|
| 1080 |
|
| 1081 | |
| 1082 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
|
| 1083 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
| 1084 | * the lock and this task is uninteresting. If we return nonzero, we have
|
| 1085 | * released the lock and the system call should return.
|
| 1086 |
|
| 1087 | static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
|
| 1088 | {
|
| 1089 | int state, status;
|
| 1090 | pid_t pid = task_pid_vnr(p);
|
| 1091 | uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
|
| 1092 | struct waitid_info *infop;
|
| 1093 |
|
| 1094 | if (!likely(wo->wo_flags & WEXITED))
|
| 1095 | return 0;
|
| 1096 |
|
| 1097 | if (unlikely(wo->wo_flags & WNOWAIT)) {
|
| 1098 | status = (p->signal->flags & SIGNAL_GROUP_EXIT)
|
| 1099 | ? p->signal->group_exit_code : p->exit_code;
|
| 1100 | get_task_struct(p);
|
| 1101 | read_unlock(&tasklist_lock);
|
| 1102 | sched_annotate_sleep();
|
| 1103 | if (wo->wo_rusage)
|
| 1104 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1105 | put_task_struct(p);
|
| 1106 | goto out_info;
|
| 1107 | }
|
| 1108 | |
| 1109 | * Move the task's state to DEAD/TRACE, only one thread can do this.
|
| 1110 |
|
| 1111 | state = (ptrace_reparented(p) && thread_group_leader(p)) ?
|
| 1112 | EXIT_TRACE : EXIT_DEAD;
|
| 1113 | if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE)
|
| 1114 | return 0;
|
| 1115 | |
| 1116 | * We own this thread, nobody else can reap it.
|
| 1117 |
|
| 1118 | read_unlock(&tasklist_lock);
|
| 1119 | sched_annotate_sleep();
|
| 1120 |
|
| 1121 | |
| 1122 | * Check thread_group_leader() to exclude the traced sub-threads.
|
| 1123 |
|
| 1124 | if (state == EXIT_DEAD && thread_group_leader(p)) {
|
| 1125 | struct signal_struct *sig = p->signal;
|
| 1126 | struct signal_struct *psig = current->signal;
|
| 1127 | unsigned long maxrss;
|
| 1128 | u64 tgutime, tgstime;
|
| 1129 |
|
| 1130 | |
| 1131 | * The resource counters for the group leader are in its
|
| 1132 | * own task_struct. Those for dead threads in the group
|
| 1133 | * are in its signal_struct, as are those for the child
|
| 1134 | * processes it has previously reaped. All these
|
| 1135 | * accumulate in the parent's signal_struct c* fields.
|
| 1136 | *
|
| 1137 | * We don't bother to take a lock here to protect these
|
| 1138 | * p->signal fields because the whole thread group is dead
|
| 1139 | * and nobody can change them.
|
| 1140 | *
|
| 1141 | * psig->stats_lock also protects us from our sub-threads
|
| 1142 | * which can reap other children at the same time. Until
|
| 1143 | * we change k_getrusage()-like users to rely on this lock
|
| 1144 | * we have to take ->siglock as well.
|
| 1145 | *
|
| 1146 | * We use thread_group_cputime_adjusted() to get times for
|
| 1147 | * the thread group, which consolidates times for all threads
|
| 1148 | * in the group including the group leader.
|
| 1149 |
|
| 1150 | thread_group_cputime_adjusted(p, &tgutime, &tgstime);
|
| 1151 | spin_lock_irq(¤t->sighand->siglock);
|
| 1152 | write_seqlock(&psig->stats_lock);
|
| 1153 | psig->cutime += tgutime + sig->cutime;
|
| 1154 | psig->cstime += tgstime + sig->cstime;
|
| 1155 | psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
|
| 1156 | psig->cmin_flt +=
|
| 1157 | p->min_flt + sig->min_flt + sig->cmin_flt;
|
| 1158 | psig->cmaj_flt +=
|
| 1159 | p->maj_flt + sig->maj_flt + sig->cmaj_flt;
|
| 1160 | psig->cnvcsw +=
|
| 1161 | p->nvcsw + sig->nvcsw + sig->cnvcsw;
|
| 1162 | psig->cnivcsw +=
|
| 1163 | p->nivcsw + sig->nivcsw + sig->cnivcsw;
|
| 1164 | psig->cinblock +=
|
| 1165 | task_io_get_inblock(p) +
|
| 1166 | sig->inblock + sig->cinblock;
|
| 1167 | psig->coublock +=
|
| 1168 | task_io_get_oublock(p) +
|
| 1169 | sig->oublock + sig->coublock;
|
| 1170 | maxrss = max(sig->maxrss, sig->cmaxrss);
|
| 1171 | if (psig->cmaxrss < maxrss)
|
| 1172 | psig->cmaxrss = maxrss;
|
| 1173 | task_io_accounting_add(&psig->ioac, &p->ioac);
|
| 1174 | task_io_accounting_add(&psig->ioac, &sig->ioac);
|
| 1175 | write_sequnlock(&psig->stats_lock);
|
| 1176 | spin_unlock_irq(¤t->sighand->siglock);
|
| 1177 | }
|
| 1178 |
|
| 1179 | if (wo->wo_rusage)
|
| 1180 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1181 | status = (p->signal->flags & SIGNAL_GROUP_EXIT)
|
| 1182 | ? p->signal->group_exit_code : p->exit_code;
|
| 1183 | wo->wo_stat = status;
|
| 1184 |
|
| 1185 | if (state == EXIT_TRACE) {
|
| 1186 | write_lock_irq(&tasklist_lock);
|
| 1187 |
|
| 1188 | ptrace_unlink(p);
|
| 1189 |
|
| 1190 |
|
| 1191 | state = EXIT_ZOMBIE;
|
| 1192 | if (do_notify_parent(p, p->exit_signal))
|
| 1193 | state = EXIT_DEAD;
|
| 1194 | p->exit_state = state;
|
| 1195 | write_unlock_irq(&tasklist_lock);
|
| 1196 | }
|
| 1197 | if (state == EXIT_DEAD)
|
| 1198 | release_task(p);
|
| 1199 |
|
| 1200 | out_info:
|
| 1201 | infop = wo->wo_info;
|
| 1202 | if (infop) {
|
| 1203 | if ((status & 0x7f) == 0) {
|
| 1204 | infop->cause = CLD_EXITED;
|
| 1205 | infop->status = status >> 8;
|
| 1206 | } else {
|
| 1207 | infop->cause = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
|
| 1208 | infop->status = status & 0x7f;
|
| 1209 | }
|
| 1210 | infop->pid = pid;
|
| 1211 | infop->uid = uid;
|
| 1212 | }
|
| 1213 |
|
| 1214 | return pid;
|
| 1215 | }
|
| 1216 |
|
| 1217 | static int *task_stopped_code(struct task_struct *p, bool ptrace)
|
| 1218 | {
|
| 1219 | if (ptrace) {
|
| 1220 | if (task_is_traced(p) && !(p->jobctl & JOBCTL_LISTENING))
|
| 1221 | return &p->exit_code;
|
| 1222 | } else {
|
| 1223 | if (p->signal->flags & SIGNAL_STOP_STOPPED)
|
| 1224 | return &p->signal->group_exit_code;
|
| 1225 | }
|
| 1226 | return NULL;
|
| 1227 | }
|
| 1228 |
|
| 1229 | |
| 1230 | * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
|
| 1231 | * @wo: wait options
|
| 1232 | * @ptrace: is the wait for ptrace
|
| 1233 | * @p: task to wait for
|
| 1234 | *
|
| 1235 | * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
|
| 1236 | *
|
| 1237 | * CONTEXT:
|
| 1238 | * read_lock(&tasklist_lock), which is released if return value is
|
| 1239 | * non-zero. Also, grabs and releases @p->sighand->siglock.
|
| 1240 | *
|
| 1241 | * RETURNS:
|
| 1242 | * 0 if wait condition didn't exist and search for other wait conditions
|
| 1243 | * should continue. Non-zero return, -errno on failure and @p's pid on
|
| 1244 | * success, implies that tasklist_lock is released and wait condition
|
| 1245 | * search should terminate.
|
| 1246 |
|
| 1247 | static int wait_task_stopped(struct wait_opts *wo,
|
| 1248 | int ptrace, struct task_struct *p)
|
| 1249 | {
|
| 1250 | struct waitid_info *infop;
|
| 1251 | int exit_code, *p_code, why;
|
| 1252 | uid_t uid = 0;
|
| 1253 | pid_t pid;
|
| 1254 |
|
| 1255 | |
| 1256 | * Traditionally we see ptrace'd stopped tasks regardless of options.
|
| 1257 |
|
| 1258 | if (!ptrace && !(wo->wo_flags & WUNTRACED))
|
| 1259 | return 0;
|
| 1260 |
|
| 1261 | if (!task_stopped_code(p, ptrace))
|
| 1262 | return 0;
|
| 1263 |
|
| 1264 | exit_code = 0;
|
| 1265 | spin_lock_irq(&p->sighand->siglock);
|
| 1266 |
|
| 1267 | p_code = task_stopped_code(p, ptrace);
|
| 1268 | if (unlikely(!p_code))
|
| 1269 | goto unlock_sig;
|
| 1270 |
|
| 1271 | exit_code = *p_code;
|
| 1272 | if (!exit_code)
|
| 1273 | goto unlock_sig;
|
| 1274 |
|
| 1275 | if (!unlikely(wo->wo_flags & WNOWAIT))
|
| 1276 | *p_code = 0;
|
| 1277 |
|
| 1278 | uid = from_kuid_munged(current_user_ns(), task_uid(p));
|
| 1279 | unlock_sig:
|
| 1280 | spin_unlock_irq(&p->sighand->siglock);
|
| 1281 | if (!exit_code)
|
| 1282 | return 0;
|
| 1283 |
|
| 1284 | |
| 1285 | * Now we are pretty sure this task is interesting.
|
| 1286 | * Make sure it doesn't get reaped out from under us while we
|
| 1287 | * give up the lock and then examine it below. We don't want to
|
| 1288 | * keep holding onto the tasklist_lock while we call getrusage and
|
| 1289 | * possibly take page faults for user memory.
|
| 1290 |
|
| 1291 | get_task_struct(p);
|
| 1292 | pid = task_pid_vnr(p);
|
| 1293 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
|
| 1294 | read_unlock(&tasklist_lock);
|
| 1295 | sched_annotate_sleep();
|
| 1296 | if (wo->wo_rusage)
|
| 1297 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1298 | put_task_struct(p);
|
| 1299 |
|
| 1300 | if (likely(!(wo->wo_flags & WNOWAIT)))
|
| 1301 | wo->wo_stat = (exit_code << 8) | 0x7f;
|
| 1302 |
|
| 1303 | infop = wo->wo_info;
|
| 1304 | if (infop) {
|
| 1305 | infop->cause = why;
|
| 1306 | infop->status = exit_code;
|
| 1307 | infop->pid = pid;
|
| 1308 | infop->uid = uid;
|
| 1309 | }
|
| 1310 | return pid;
|
| 1311 | }
|
| 1312 |
|
| 1313 | |
| 1314 | * Handle do_wait work for one task in a live, non-stopped state.
|
| 1315 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
|
| 1316 | * the lock and this task is uninteresting. If we return nonzero, we have
|
| 1317 | * released the lock and the system call should return.
|
| 1318 |
|
| 1319 | static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
|
| 1320 | {
|
| 1321 | struct waitid_info *infop;
|
| 1322 | pid_t pid;
|
| 1323 | uid_t uid;
|
| 1324 |
|
| 1325 | if (!unlikely(wo->wo_flags & WCONTINUED))
|
| 1326 | return 0;
|
| 1327 |
|
| 1328 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
|
| 1329 | return 0;
|
| 1330 |
|
| 1331 | spin_lock_irq(&p->sighand->siglock);
|
| 1332 |
|
| 1333 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
|
| 1334 | spin_unlock_irq(&p->sighand->siglock);
|
| 1335 | return 0;
|
| 1336 | }
|
| 1337 | if (!unlikely(wo->wo_flags & WNOWAIT))
|
| 1338 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
|
| 1339 | uid = from_kuid_munged(current_user_ns(), task_uid(p));
|
| 1340 | spin_unlock_irq(&p->sighand->siglock);
|
| 1341 |
|
| 1342 | pid = task_pid_vnr(p);
|
| 1343 | get_task_struct(p);
|
| 1344 | read_unlock(&tasklist_lock);
|
| 1345 | sched_annotate_sleep();
|
| 1346 | if (wo->wo_rusage)
|
| 1347 | getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
|
| 1348 | put_task_struct(p);
|
| 1349 |
|
| 1350 | infop = wo->wo_info;
|
| 1351 | if (!infop) {
|
| 1352 | wo->wo_stat = 0xffff;
|
| 1353 | } else {
|
| 1354 | infop->cause = CLD_CONTINUED;
|
| 1355 | infop->pid = pid;
|
| 1356 | infop->uid = uid;
|
| 1357 | infop->status = SIGCONT;
|
| 1358 | }
|
| 1359 | return pid;
|
| 1360 | }
|
| 1361 |
|
| 1362 | |
| 1363 | * Consider @p for a wait by @parent.
|
| 1364 | *
|
| 1365 | * -ECHILD should be in ->notask_error before the first call.
|
| 1366 | * Returns nonzero for a final return, when we have unlocked tasklist_lock.
|
| 1367 | * Returns zero if the search for a child should continue;
|
| 1368 | * then ->notask_error is 0 if @p is an eligible child,
|
| 1369 | * or still -ECHILD.
|
| 1370 |
|
| 1371 | static int wait_consider_task(struct wait_opts *wo, int ptrace,
|
| 1372 | struct task_struct *p)
|
| 1373 | {
|
| 1374 | |
| 1375 | * We can race with wait_task_zombie() from another thread.
|
| 1376 | * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
|
| 1377 | * can't confuse the checks below.
|
| 1378 |
|
| 1379 | int exit_state = READ_ONCE(p->exit_state);
|
| 1380 | int ret;
|
| 1381 |
|
| 1382 | if (unlikely(exit_state == EXIT_DEAD))
|
| 1383 | return 0;
|
| 1384 |
|
| 1385 | ret = eligible_child(wo, ptrace, p);
|
| 1386 | if (!ret)
|
| 1387 | return ret;
|
| 1388 |
|
| 1389 | if (unlikely(exit_state == EXIT_TRACE)) {
|
| 1390 | |
| 1391 | * ptrace == 0 means we are the natural parent. In this case
|
| 1392 | * we should clear notask_error, debugger will notify us.
|
| 1393 |
|
| 1394 | if (likely(!ptrace))
|
| 1395 | wo->notask_error = 0;
|
| 1396 | return 0;
|
| 1397 | }
|
| 1398 |
|
| 1399 | if (likely(!ptrace) && unlikely(p->ptrace)) {
|
| 1400 | |
| 1401 | * If it is traced by its real parent's group, just pretend
|
| 1402 | * the caller is ptrace_do_wait() and reap this child if it
|
| 1403 | * is zombie.
|
| 1404 | *
|
| 1405 | * This also hides group stop state from real parent; otherwise
|
| 1406 | * a single stop can be reported twice as group and ptrace stop.
|
| 1407 | * If a ptracer wants to distinguish these two events for its
|
| 1408 | * own children it should create a separate process which takes
|
| 1409 | * the role of real parent.
|
| 1410 |
|
| 1411 | if (!ptrace_reparented(p))
|
| 1412 | ptrace = 1;
|
| 1413 | }
|
| 1414 |
|
| 1415 |
|
| 1416 | if (exit_state == EXIT_ZOMBIE) {
|
| 1417 |
|
| 1418 | if (!delay_group_leader(p)) {
|
| 1419 | |
| 1420 | * A zombie ptracee is only visible to its ptracer.
|
| 1421 | * Notification and reaping will be cascaded to the
|
| 1422 | * real parent when the ptracer detaches.
|
| 1423 |
|
| 1424 | if (unlikely(ptrace) || likely(!p->ptrace))
|
| 1425 | return wait_task_zombie(wo, p);
|
| 1426 | }
|
| 1427 |
|
| 1428 | |
| 1429 | * Allow access to stopped/continued state via zombie by
|
| 1430 | * falling through. Clearing of notask_error is complex.
|
| 1431 | *
|
| 1432 | * When !@ptrace:
|
| 1433 | *
|
| 1434 | * If WEXITED is set, notask_error should naturally be
|
| 1435 | * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
|
| 1436 | * so, if there are live subthreads, there are events to
|
| 1437 | * wait for. If all subthreads are dead, it's still safe
|
| 1438 | * to clear - this function will be called again in finite
|
| 1439 | * amount time once all the subthreads are released and
|
| 1440 | * will then return without clearing.
|
| 1441 | *
|
| 1442 | * When @ptrace:
|
| 1443 | *
|
| 1444 | * Stopped state is per-task and thus can't change once the
|
| 1445 | * target task dies. Only continued and exited can happen.
|
| 1446 | * Clear notask_error if WCONTINUED | WEXITED.
|
| 1447 |
|
| 1448 | if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
|
| 1449 | wo->notask_error = 0;
|
| 1450 | } else {
|
| 1451 | |
| 1452 | * @p is alive and it's gonna stop, continue or exit, so
|
| 1453 | * there always is something to wait for.
|
| 1454 |
|
| 1455 | wo->notask_error = 0;
|
| 1456 | }
|
| 1457 |
|
| 1458 | |
| 1459 | * Wait for stopped. Depending on @ptrace, different stopped state
|
| 1460 | * is used and the two don't interact with each other.
|
| 1461 |
|
| 1462 | ret = wait_task_stopped(wo, ptrace, p);
|
| 1463 | if (ret)
|
| 1464 | return ret;
|
| 1465 |
|
| 1466 | |
| 1467 | * Wait for continued. There's only one continued state and the
|
| 1468 | * ptracer can consume it which can confuse the real parent. Don't
|
| 1469 | * use WCONTINUED from ptracer. You don't need or want it.
|
| 1470 |
|
| 1471 | return wait_task_continued(wo, p);
|
| 1472 | }
|
| 1473 |
|
| 1474 | |
| 1475 | * Do the work of do_wait() for one thread in the group, @tsk.
|
| 1476 | *
|
| 1477 | * -ECHILD should be in ->notask_error before the first call.
|
| 1478 | * Returns nonzero for a final return, when we have unlocked tasklist_lock.
|
| 1479 | * Returns zero if the search for a child should continue; then
|
| 1480 | * ->notask_error is 0 if there were any eligible children,
|
| 1481 | * or still -ECHILD.
|
| 1482 |
|
| 1483 | static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
|
| 1484 | {
|
| 1485 | struct task_struct *p;
|
| 1486 |
|
| 1487 | list_for_each_entry(p, &tsk->children, sibling) {
|
| 1488 | int ret = wait_consider_task(wo, 0, p);
|
| 1489 |
|
| 1490 | if (ret)
|
| 1491 | return ret;
|
| 1492 | }
|
| 1493 |
|
| 1494 | return 0;
|
| 1495 | }
|
| 1496 |
|
| 1497 | static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
|
| 1498 | {
|
| 1499 | struct task_struct *p;
|
| 1500 |
|
| 1501 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
|
| 1502 | int ret = wait_consider_task(wo, 1, p);
|
| 1503 |
|
| 1504 | if (ret)
|
| 1505 | return ret;
|
| 1506 | }
|
| 1507 |
|
| 1508 | return 0;
|
| 1509 | }
|
| 1510 |
|
| 1511 | static int child_wait_callback(wait_queue_entry_t *wait, unsigned mode,
|
| 1512 | int sync, void *key)
|
| 1513 | {
|
| 1514 | struct wait_opts *wo = container_of(wait, struct wait_opts,
|
| 1515 | child_wait);
|
| 1516 | struct task_struct *p = key;
|
| 1517 |
|
| 1518 | if (!eligible_pid(wo, p))
|
| 1519 | return 0;
|
| 1520 |
|
| 1521 | if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
|
| 1522 | return 0;
|
| 1523 |
|
| 1524 | return default_wake_function(wait, mode, sync, key);
|
| 1525 | }
|
| 1526 |
|
| 1527 | void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
|
| 1528 | {
|
| 1529 | __wake_up_sync_key(&parent->signal->wait_chldexit,
|
| 1530 | TASK_INTERRUPTIBLE, p);
|
| 1531 | }
|
| 1532 |
|
| 1533 | static bool is_effectively_child(struct wait_opts *wo, bool ptrace,
|
| 1534 | struct task_struct *target)
|
| 1535 | {
|
| 1536 | struct task_struct *parent =
|
| 1537 | !ptrace ? target->real_parent : target->parent;
|
| 1538 |
|
| 1539 | return current == parent || (!(wo->wo_flags & __WNOTHREAD) &&
|
| 1540 | same_thread_group(current, parent));
|
| 1541 | }
|
| 1542 |
|
| 1543 | |
| 1544 | * Optimization for waiting on PIDTYPE_PID. No need to iterate through child
|
| 1545 | * and tracee lists to find the target task.
|
| 1546 |
|
| 1547 | static int do_wait_pid(struct wait_opts *wo)
|
| 1548 | {
|
| 1549 | bool ptrace;
|
| 1550 | struct task_struct *target;
|
| 1551 | int retval;
|
| 1552 |
|
| 1553 | ptrace = false;
|
| 1554 | target = pid_task(wo->wo_pid, PIDTYPE_TGID);
|
| 1555 | if (target && is_effectively_child(wo, ptrace, target)) {
|
| 1556 | retval = wait_consider_task(wo, ptrace, target);
|
| 1557 | if (retval)
|
| 1558 | return retval;
|
| 1559 | }
|
| 1560 |
|
| 1561 | ptrace = true;
|
| 1562 | target = pid_task(wo->wo_pid, PIDTYPE_PID);
|
| 1563 | if (target && target->ptrace &&
|
| 1564 | is_effectively_child(wo, ptrace, target)) {
|
| 1565 | retval = wait_consider_task(wo, ptrace, target);
|
| 1566 | if (retval)
|
| 1567 | return retval;
|
| 1568 | }
|
| 1569 |
|
| 1570 | return 0;
|
| 1571 | }
|
| 1572 |
|
| 1573 | static long do_wait(struct wait_opts *wo)
|
| 1574 | {
|
| 1575 | int retval;
|
| 1576 |
|
| 1577 | trace_sched_process_wait(wo->wo_pid);
|
| 1578 |
|
| 1579 | init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
|
| 1580 | wo->child_wait.private = current;
|
| 1581 | add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
|
| 1582 | repeat:
|
| 1583 | |
| 1584 | * If there is nothing that can match our criteria, just get out.
|
| 1585 | * We will clear ->notask_error to zero if we see any child that
|
| 1586 | * might later match our criteria, even if we are not able to reap
|
| 1587 | * it yet.
|
| 1588 |
|
| 1589 | wo->notask_error = -ECHILD;
|
| 1590 | if ((wo->wo_type < PIDTYPE_MAX) &&
|
| 1591 | (!wo->wo_pid || !pid_has_task(wo->wo_pid, wo->wo_type)))
|
| 1592 | goto notask;
|
| 1593 |
|
| 1594 | set_current_state(TASK_INTERRUPTIBLE);
|
| 1595 | read_lock(&tasklist_lock);
|
| 1596 |
|
| 1597 | if (wo->wo_type == PIDTYPE_PID) {
|
| 1598 | retval = do_wait_pid(wo);
|
| 1599 | if (retval)
|
| 1600 | goto end;
|
| 1601 | } else {
|
| 1602 | struct task_struct *tsk = current;
|
| 1603 |
|
| 1604 | do {
|
| 1605 | retval = do_wait_thread(wo, tsk);
|
| 1606 | if (retval)
|
| 1607 | goto end;
|
| 1608 |
|
| 1609 | retval = ptrace_do_wait(wo, tsk);
|
| 1610 | if (retval)
|
| 1611 | goto end;
|
| 1612 |
|
| 1613 | if (wo->wo_flags & __WNOTHREAD)
|
| 1614 | break;
|
| 1615 | } while_each_thread(current, tsk);
|
| 1616 | }
|
| 1617 | read_unlock(&tasklist_lock);
|
| 1618 |
|
| 1619 | notask:
|
| 1620 | retval = wo->notask_error;
|
| 1621 | if (!retval && !(wo->wo_flags & WNOHANG)) {
|
| 1622 | retval = -ERESTARTSYS;
|
| 1623 | if (!signal_pending(current)) {
|
| 1624 | schedule();
|
| 1625 | goto repeat;
|
| 1626 | }
|
| 1627 | }
|
| 1628 | end:
|
| 1629 | __set_current_state(TASK_RUNNING);
|
| 1630 | remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
|
| 1631 | return retval;
|
| 1632 | }
|
| 1633 |
|
| 1634 | static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
|
| 1635 | int options, struct rusage *ru)
|
| 1636 | {
|
| 1637 | struct wait_opts wo;
|
| 1638 | struct pid *pid = NULL;
|
| 1639 | enum pid_type type;
|
| 1640 | long ret;
|
| 1641 | unsigned int f_flags = 0;
|
| 1642 |
|
| 1643 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED|
|
| 1644 | __WNOTHREAD|__WCLONE|__WALL))
|
| 1645 | return -EINVAL;
|
| 1646 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
|
| 1647 | return -EINVAL;
|
| 1648 |
|
| 1649 | switch (which) {
|
| 1650 | case P_ALL:
|
| 1651 | type = PIDTYPE_MAX;
|
| 1652 | break;
|
| 1653 | case P_PID:
|
| 1654 | type = PIDTYPE_PID;
|
| 1655 | if (upid <= 0)
|
| 1656 | return -EINVAL;
|
| 1657 |
|
| 1658 | pid = find_get_pid(upid);
|
| 1659 | break;
|
| 1660 | case P_PGID:
|
| 1661 | type = PIDTYPE_PGID;
|
| 1662 | if (upid < 0)
|
| 1663 | return -EINVAL;
|
| 1664 |
|
| 1665 | if (upid)
|
| 1666 | pid = find_get_pid(upid);
|
| 1667 | else
|
| 1668 | pid = get_task_pid(current, PIDTYPE_PGID);
|
| 1669 | break;
|
| 1670 | case P_PIDFD:
|
| 1671 | type = PIDTYPE_PID;
|
| 1672 | if (upid < 0)
|
| 1673 | return -EINVAL;
|
| 1674 |
|
| 1675 | pid = pidfd_get_pid(upid, &f_flags);
|
| 1676 | if (IS_ERR(pid))
|
| 1677 | return PTR_ERR(pid);
|
| 1678 |
|
| 1679 | break;
|
| 1680 | default:
|
| 1681 | return -EINVAL;
|
| 1682 | }
|
| 1683 |
|
| 1684 | wo.wo_type = type;
|
| 1685 | wo.wo_pid = pid;
|
| 1686 | wo.wo_flags = options;
|
| 1687 | wo.wo_info = infop;
|
| 1688 | wo.wo_rusage = ru;
|
| 1689 | if (f_flags & O_NONBLOCK)
|
| 1690 | wo.wo_flags |= WNOHANG;
|
| 1691 |
|
| 1692 | ret = do_wait(&wo);
|
| 1693 | if (!ret && !(options & WNOHANG) && (f_flags & O_NONBLOCK))
|
| 1694 | ret = -EAGAIN;
|
| 1695 |
|
| 1696 | put_pid(pid);
|
| 1697 | return ret;
|
| 1698 | }
|
| 1699 |
|
| 1700 | SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
|
| 1701 | infop, int, options, struct rusage __user *, ru)
|
| 1702 | {
|
| 1703 | struct rusage r;
|
| 1704 | struct waitid_info info = {.status = 0};
|
| 1705 | long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
|
| 1706 | int signo = 0;
|
| 1707 |
|
| 1708 | if (err > 0) {
|
| 1709 | signo = SIGCHLD;
|
| 1710 | err = 0;
|
| 1711 | if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
|
| 1712 | return -EFAULT;
|
| 1713 | }
|
| 1714 | if (!infop)
|
| 1715 | return err;
|
| 1716 |
|
| 1717 | if (!user_write_access_begin(infop, sizeof(*infop)))
|
| 1718 | return -EFAULT;
|
| 1719 |
|
| 1720 | unsafe_put_user(signo, &infop->si_signo, Efault);
|
| 1721 | unsafe_put_user(0, &infop->si_errno, Efault);
|
| 1722 | unsafe_put_user(info.cause, &infop->si_code, Efault);
|
| 1723 | unsafe_put_user(info.pid, &infop->si_pid, Efault);
|
| 1724 | unsafe_put_user(info.uid, &infop->si_uid, Efault);
|
| 1725 | unsafe_put_user(info.status, &infop->si_status, Efault);
|
| 1726 | user_write_access_end();
|
| 1727 | return err;
|
| 1728 | Efault:
|
| 1729 | user_write_access_end();
|
| 1730 | return -EFAULT;
|
| 1731 | }
|
| 1732 |
|
| 1733 | long kernel_wait4(pid_t upid, int __user *stat_addr, int options,
|
| 1734 | struct rusage *ru)
|
| 1735 | {
|
| 1736 | struct wait_opts wo;
|
| 1737 | struct pid *pid = NULL;
|
| 1738 | enum pid_type type;
|
| 1739 | long ret;
|
| 1740 |
|
| 1741 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
|
| 1742 | __WNOTHREAD|__WCLONE|__WALL))
|
| 1743 | return -EINVAL;
|
| 1744 |
|
| 1745 |
|
| 1746 | if (upid == INT_MIN)
|
| 1747 | return -ESRCH;
|
| 1748 |
|
| 1749 | if (upid == -1)
|
| 1750 | type = PIDTYPE_MAX;
|
| 1751 | else if (upid < 0) {
|
| 1752 | type = PIDTYPE_PGID;
|
| 1753 | pid = find_get_pid(-upid);
|
| 1754 | } else if (upid == 0) {
|
| 1755 | type = PIDTYPE_PGID;
|
| 1756 | pid = get_task_pid(current, PIDTYPE_PGID);
|
| 1757 | } else {
|
| 1758 | type = PIDTYPE_PID;
|
| 1759 | pid = find_get_pid(upid);
|
| 1760 | }
|
| 1761 |
|
| 1762 | wo.wo_type = type;
|
| 1763 | wo.wo_pid = pid;
|
| 1764 | wo.wo_flags = options | WEXITED;
|
| 1765 | wo.wo_info = NULL;
|
| 1766 | wo.wo_stat = 0;
|
| 1767 | wo.wo_rusage = ru;
|
| 1768 | ret = do_wait(&wo);
|
| 1769 | put_pid(pid);
|
| 1770 | if (ret > 0 && stat_addr && put_user(wo.wo_stat, stat_addr))
|
| 1771 | ret = -EFAULT;
|
| 1772 |
|
| 1773 | return ret;
|
| 1774 | }
|
| 1775 |
|
| 1776 | int kernel_wait(pid_t pid, int *stat)
|
| 1777 | {
|
| 1778 | struct wait_opts wo = {
|
| 1779 | .wo_type = PIDTYPE_PID,
|
| 1780 | .wo_pid = find_get_pid(pid),
|
| 1781 | .wo_flags = WEXITED,
|
| 1782 | };
|
| 1783 | int ret;
|
| 1784 |
|
| 1785 | ret = do_wait(&wo);
|
| 1786 | if (ret > 0 && wo.wo_stat)
|
| 1787 | *stat = wo.wo_stat;
|
| 1788 | put_pid(wo.wo_pid);
|
| 1789 | return ret;
|
| 1790 | }
|
| 1791 |
|
| 1792 | SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
|
| 1793 | int, options, struct rusage __user *, ru)
|
| 1794 | {
|
| 1795 | struct rusage r;
|
| 1796 | long err = kernel_wait4(upid, stat_addr, options, ru ? &r : NULL);
|
| 1797 |
|
| 1798 | if (err > 0) {
|
| 1799 | if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
|
| 1800 | return -EFAULT;
|
| 1801 | }
|
| 1802 | return err;
|
| 1803 | }
|
| 1804 |
|
| 1805 | #ifdef __ARCH_WANT_SYS_WAITPID
|
| 1806 |
|
| 1807 | |
| 1808 | * sys_waitpid() remains for compatibility. waitpid() should be
|
| 1809 | * implemented by calling sys_wait4() from libc.a.
|
| 1810 |
|
| 1811 | SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
|
| 1812 | {
|
| 1813 | return kernel_wait4(pid, stat_addr, options, NULL);
|
| 1814 | }
|
| 1815 |
|
| 1816 | #endif
|
| 1817 |
|
| 1818 | #ifdef CONFIG_COMPAT
|
| 1819 | COMPAT_SYSCALL_DEFINE4(wait4,
|
| 1820 | compat_pid_t, pid,
|
| 1821 | compat_uint_t __user *, stat_addr,
|
| 1822 | int, options,
|
| 1823 | struct compat_rusage __user *, ru)
|
| 1824 | {
|
| 1825 | struct rusage r;
|
| 1826 | long err = kernel_wait4(pid, stat_addr, options, ru ? &r : NULL);
|
| 1827 | if (err > 0) {
|
| 1828 | if (ru && put_compat_rusage(&r, ru))
|
| 1829 | return -EFAULT;
|
| 1830 | }
|
| 1831 | return err;
|
| 1832 | }
|
| 1833 |
|
| 1834 | COMPAT_SYSCALL_DEFINE5(waitid,
|
| 1835 | int, which, compat_pid_t, pid,
|
| 1836 | struct compat_siginfo __user *, infop, int, options,
|
| 1837 | struct compat_rusage __user *, uru)
|
| 1838 | {
|
| 1839 | struct rusage ru;
|
| 1840 | struct waitid_info info = {.status = 0};
|
| 1841 | long err = kernel_waitid(which, pid, &info, options, uru ? &ru : NULL);
|
| 1842 | int signo = 0;
|
| 1843 | if (err > 0) {
|
| 1844 | signo = SIGCHLD;
|
| 1845 | err = 0;
|
| 1846 | if (uru) {
|
| 1847 |
|
| 1848 | if (COMPAT_USE_64BIT_TIME)
|
| 1849 | err = copy_to_user(uru, &ru, sizeof(ru));
|
| 1850 | else
|
| 1851 | err = put_compat_rusage(&ru, uru);
|
| 1852 | if (err)
|
| 1853 | return -EFAULT;
|
| 1854 | }
|
| 1855 | }
|
| 1856 |
|
| 1857 | if (!infop)
|
| 1858 | return err;
|
| 1859 |
|
| 1860 | if (!user_write_access_begin(infop, sizeof(*infop)))
|
| 1861 | return -EFAULT;
|
| 1862 |
|
| 1863 | unsafe_put_user(signo, &infop->si_signo, Efault);
|
| 1864 | unsafe_put_user(0, &infop->si_errno, Efault);
|
| 1865 | unsafe_put_user(info.cause, &infop->si_code, Efault);
|
| 1866 | unsafe_put_user(info.pid, &infop->si_pid, Efault);
|
| 1867 | unsafe_put_user(info.uid, &infop->si_uid, Efault);
|
| 1868 | unsafe_put_user(info.status, &infop->si_status, Efault);
|
| 1869 | user_write_access_end();
|
| 1870 | return err;
|
| 1871 | Efault:
|
| 1872 | user_write_access_end();
|
| 1873 | return -EFAULT;
|
| 1874 | }
|
| 1875 | #endif
|
| 1876 |
|
| 1877 | |
| 1878 | * thread_group_exited - check that a thread group has exited
|
| 1879 | * @pid: tgid of thread group to be checked.
|
| 1880 | *
|
| 1881 | * Test if the thread group represented by tgid has exited (all
|
| 1882 | * threads are zombies, dead or completely gone).
|
| 1883 | *
|
| 1884 | * Return: true if the thread group has exited. false otherwise.
|
| 1885 |
|
| 1886 | bool thread_group_exited(struct pid *pid)
|
| 1887 | {
|
| 1888 | struct task_struct *task;
|
| 1889 | bool exited;
|
| 1890 |
|
| 1891 | rcu_read_lock();
|
| 1892 | task = pid_task(pid, PIDTYPE_PID);
|
| 1893 | exited = !task ||
|
| 1894 | (READ_ONCE(task->exit_state) && thread_group_empty(task));
|
| 1895 | rcu_read_unlock();
|
| 1896 |
|
| 1897 | return exited;
|
| 1898 | }
|
| 1899 | EXPORT_SYMBOL(thread_group_exited);
|
| 1900 |
|
| 1901 | __weak void abort(void)
|
| 1902 | {
|
| 1903 | BUG();
|
| 1904 |
|
| 1905 |
|
| 1906 | panic("Oops failed to kill thread");
|
| 1907 | }
|
| 1908 | EXPORT_SYMBOL(abort);
|