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