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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/binfmts.h> |
24 | #include <linux/nsproxy.h> |
25 | #include <linux/pid_namespace.h> |
26 | #include <linux/ptrace.h> |
27 | #include <linux/profile.h> |
28 | #include <linux/mount.h> |
29 | #include <linux/proc_fs.h> |
30 | #include <linux/kthread.h> |
31 | #include <linux/mempolicy.h> |
32 | #include <linux/taskstats_kern.h> |
33 | #include <linux/delayacct.h> |
34 | #include <linux/freezer.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> /* for audit_free() */ |
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 | |
55 | #include <asm/uaccess.h> |
56 | #include <asm/unistd.h> |
57 | #include <asm/pgtable.h> |
58 | #include <asm/mmu_context.h> |
59 | |
60 | static void exit_mm(struct task_struct * tsk); |
61 | |
62 | static void __unhash_process(struct task_struct *p, bool group_dead) |
63 | { |
64 | nr_threads--; |
65 | detach_pid(p, PIDTYPE_PID); |
66 | if (group_dead) { |
67 | detach_pid(p, PIDTYPE_PGID); |
68 | detach_pid(p, PIDTYPE_SID); |
69 | |
70 | list_del_rcu(&p->tasks); |
71 | list_del_init(&p->sibling); |
72 | __this_cpu_dec(process_counts); |
73 | } |
74 | list_del_rcu(&p->thread_group); |
75 | } |
76 | |
77 | /* |
78 | * This function expects the tasklist_lock write-locked. |
79 | */ |
80 | static void __exit_signal(struct task_struct *tsk) |
81 | { |
82 | struct signal_struct *sig = tsk->signal; |
83 | bool group_dead = thread_group_leader(tsk); |
84 | struct sighand_struct *sighand; |
85 | struct tty_struct *uninitialized_var(tty); |
86 | |
87 | sighand = rcu_dereference_check(tsk->sighand, |
88 | rcu_read_lock_held() || |
89 | lockdep_tasklist_lock_is_held()); |
90 | spin_lock(&sighand->siglock); |
91 | |
92 | posix_cpu_timers_exit(tsk); |
93 | if (group_dead) { |
94 | posix_cpu_timers_exit_group(tsk); |
95 | tty = sig->tty; |
96 | sig->tty = NULL; |
97 | } else { |
98 | /* |
99 | * This can only happen if the caller is de_thread(). |
100 | * FIXME: this is the temporary hack, we should teach |
101 | * posix-cpu-timers to handle this case correctly. |
102 | */ |
103 | if (unlikely(has_group_leader_pid(tsk))) |
104 | posix_cpu_timers_exit_group(tsk); |
105 | |
106 | /* |
107 | * If there is any task waiting for the group exit |
108 | * then notify it: |
109 | */ |
110 | if (sig->notify_count > 0 && !--sig->notify_count) |
111 | wake_up_process(sig->group_exit_task); |
112 | |
113 | if (tsk == sig->curr_target) |
114 | sig->curr_target = next_thread(tsk); |
115 | /* |
116 | * Accumulate here the counters for all threads but the |
117 | * group leader as they die, so they can be added into |
118 | * the process-wide totals when those are taken. |
119 | * The group leader stays around as a zombie as long |
120 | * as there are other threads. When it gets reaped, |
121 | * the exit.c code will add its counts into these totals. |
122 | * We won't ever get here for the group leader, since it |
123 | * will have been the last reference on the signal_struct. |
124 | */ |
125 | sig->utime = cputime_add(sig->utime, tsk->utime); |
126 | sig->stime = cputime_add(sig->stime, tsk->stime); |
127 | sig->gtime = cputime_add(sig->gtime, tsk->gtime); |
128 | sig->min_flt += tsk->min_flt; |
129 | sig->maj_flt += tsk->maj_flt; |
130 | sig->nvcsw += tsk->nvcsw; |
131 | sig->nivcsw += tsk->nivcsw; |
132 | sig->inblock += task_io_get_inblock(tsk); |
133 | sig->oublock += task_io_get_oublock(tsk); |
134 | task_io_accounting_add(&sig->ioac, &tsk->ioac); |
135 | sig->sum_sched_runtime += tsk->se.sum_exec_runtime; |
136 | } |
137 | |
138 | sig->nr_threads--; |
139 | __unhash_process(tsk, group_dead); |
140 | |
141 | /* |
142 | * Do this under ->siglock, we can race with another thread |
143 | * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals. |
144 | */ |
145 | flush_sigqueue(&tsk->pending); |
146 | tsk->sighand = NULL; |
147 | spin_unlock(&sighand->siglock); |
148 | |
149 | __cleanup_sighand(sighand); |
150 | clear_tsk_thread_flag(tsk,TIF_SIGPENDING); |
151 | if (group_dead) { |
152 | flush_sigqueue(&sig->shared_pending); |
153 | tty_kref_put(tty); |
154 | } |
155 | } |
156 | |
157 | static void delayed_put_task_struct(struct rcu_head *rhp) |
158 | { |
159 | struct task_struct *tsk = container_of(rhp, struct task_struct, rcu); |
160 | |
161 | perf_event_delayed_put(tsk); |
162 | trace_sched_process_free(tsk); |
163 | put_task_struct(tsk); |
164 | } |
165 | |
166 | |
167 | void release_task(struct task_struct * p) |
168 | { |
169 | struct task_struct *leader; |
170 | int zap_leader; |
171 | repeat: |
172 | tracehook_prepare_release_task(p); |
173 | /* don't need to get the RCU readlock here - the process is dead and |
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 | tracehook_finish_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) && leader->exit_state == EXIT_ZOMBIE) { |
193 | BUG_ON(task_detached(leader)); |
194 | do_notify_parent(leader, leader->exit_signal); |
195 | /* |
196 | * If we were the last child thread and the leader has |
197 | * exited already, and the leader's parent ignores SIGCHLD, |
198 | * then we are the one who should release the leader. |
199 | * |
200 | * do_notify_parent() will have marked it self-reaping in |
201 | * that case. |
202 | */ |
203 | zap_leader = task_detached(leader); |
204 | |
205 | /* |
206 | * This maintains the invariant that release_task() |
207 | * only runs on a task in EXIT_DEAD, just for sanity. |
208 | */ |
209 | if (zap_leader) |
210 | leader->exit_state = EXIT_DEAD; |
211 | } |
212 | |
213 | write_unlock_irq(&tasklist_lock); |
214 | release_thread(p); |
215 | call_rcu(&p->rcu, delayed_put_task_struct); |
216 | |
217 | p = leader; |
218 | if (unlikely(zap_leader)) |
219 | goto repeat; |
220 | } |
221 | |
222 | /* |
223 | * This checks not only the pgrp, but falls back on the pid if no |
224 | * satisfactory pgrp is found. I dunno - gdb doesn't work correctly |
225 | * without this... |
226 | * |
227 | * The caller must hold rcu lock or the tasklist lock. |
228 | */ |
229 | struct pid *session_of_pgrp(struct pid *pgrp) |
230 | { |
231 | struct task_struct *p; |
232 | struct pid *sid = NULL; |
233 | |
234 | p = pid_task(pgrp, PIDTYPE_PGID); |
235 | if (p == NULL) |
236 | p = pid_task(pgrp, PIDTYPE_PID); |
237 | if (p != NULL) |
238 | sid = task_session(p); |
239 | |
240 | return sid; |
241 | } |
242 | |
243 | /* |
244 | * Determine if a process group is "orphaned", according to the POSIX |
245 | * definition in 2.2.2.52. Orphaned process groups are not to be affected |
246 | * by terminal-generated stop signals. Newly orphaned process groups are |
247 | * to receive a SIGHUP and a SIGCONT. |
248 | * |
249 | * "I ask you, have you ever known what it is to be an orphan?" |
250 | */ |
251 | static int will_become_orphaned_pgrp(struct pid *pgrp, struct task_struct *ignored_task) |
252 | { |
253 | struct task_struct *p; |
254 | |
255 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
256 | if ((p == ignored_task) || |
257 | (p->exit_state && thread_group_empty(p)) || |
258 | is_global_init(p->real_parent)) |
259 | continue; |
260 | |
261 | if (task_pgrp(p->real_parent) != pgrp && |
262 | task_session(p->real_parent) == task_session(p)) |
263 | return 0; |
264 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
265 | |
266 | return 1; |
267 | } |
268 | |
269 | int is_current_pgrp_orphaned(void) |
270 | { |
271 | int retval; |
272 | |
273 | read_lock(&tasklist_lock); |
274 | retval = will_become_orphaned_pgrp(task_pgrp(current), NULL); |
275 | read_unlock(&tasklist_lock); |
276 | |
277 | return retval; |
278 | } |
279 | |
280 | static int has_stopped_jobs(struct pid *pgrp) |
281 | { |
282 | int retval = 0; |
283 | struct task_struct *p; |
284 | |
285 | do_each_pid_task(pgrp, PIDTYPE_PGID, p) { |
286 | if (!task_is_stopped(p)) |
287 | continue; |
288 | retval = 1; |
289 | break; |
290 | } while_each_pid_task(pgrp, PIDTYPE_PGID, p); |
291 | return retval; |
292 | } |
293 | |
294 | /* |
295 | * Check to see if any process groups have become orphaned as |
296 | * a result of our exiting, and if they have any stopped jobs, |
297 | * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) |
298 | */ |
299 | static void |
300 | kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent) |
301 | { |
302 | struct pid *pgrp = task_pgrp(tsk); |
303 | struct task_struct *ignored_task = tsk; |
304 | |
305 | if (!parent) |
306 | /* exit: our father is in a different pgrp than |
307 | * we are and we were the only connection outside. |
308 | */ |
309 | parent = tsk->real_parent; |
310 | else |
311 | /* reparent: our child is in a different pgrp than |
312 | * we are, and it was the only connection outside. |
313 | */ |
314 | ignored_task = NULL; |
315 | |
316 | if (task_pgrp(parent) != pgrp && |
317 | task_session(parent) == task_session(tsk) && |
318 | will_become_orphaned_pgrp(pgrp, ignored_task) && |
319 | has_stopped_jobs(pgrp)) { |
320 | __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp); |
321 | __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp); |
322 | } |
323 | } |
324 | |
325 | /** |
326 | * reparent_to_kthreadd - Reparent the calling kernel thread to kthreadd |
327 | * |
328 | * If a kernel thread is launched as a result of a system call, or if |
329 | * it ever exits, it should generally reparent itself to kthreadd so it |
330 | * isn't in the way of other processes and is correctly cleaned up on exit. |
331 | * |
332 | * The various task state such as scheduling policy and priority may have |
333 | * been inherited from a user process, so we reset them to sane values here. |
334 | * |
335 | * NOTE that reparent_to_kthreadd() gives the caller full capabilities. |
336 | */ |
337 | static void reparent_to_kthreadd(void) |
338 | { |
339 | write_lock_irq(&tasklist_lock); |
340 | |
341 | ptrace_unlink(current); |
342 | /* Reparent to init */ |
343 | current->real_parent = current->parent = kthreadd_task; |
344 | list_move_tail(¤t->sibling, ¤t->real_parent->children); |
345 | |
346 | /* Set the exit signal to SIGCHLD so we signal init on exit */ |
347 | current->exit_signal = SIGCHLD; |
348 | |
349 | if (task_nice(current) < 0) |
350 | set_user_nice(current, 0); |
351 | /* cpus_allowed? */ |
352 | /* rt_priority? */ |
353 | /* signals? */ |
354 | memcpy(current->signal->rlim, init_task.signal->rlim, |
355 | sizeof(current->signal->rlim)); |
356 | |
357 | atomic_inc(&init_cred.usage); |
358 | commit_creds(&init_cred); |
359 | write_unlock_irq(&tasklist_lock); |
360 | } |
361 | |
362 | void __set_special_pids(struct pid *pid) |
363 | { |
364 | struct task_struct *curr = current->group_leader; |
365 | |
366 | if (task_session(curr) != pid) |
367 | change_pid(curr, PIDTYPE_SID, pid); |
368 | |
369 | if (task_pgrp(curr) != pid) |
370 | change_pid(curr, PIDTYPE_PGID, pid); |
371 | } |
372 | |
373 | static void set_special_pids(struct pid *pid) |
374 | { |
375 | write_lock_irq(&tasklist_lock); |
376 | __set_special_pids(pid); |
377 | write_unlock_irq(&tasklist_lock); |
378 | } |
379 | |
380 | /* |
381 | * Let kernel threads use this to say that they allow a certain signal. |
382 | * Must not be used if kthread was cloned with CLONE_SIGHAND. |
383 | */ |
384 | int allow_signal(int sig) |
385 | { |
386 | if (!valid_signal(sig) || sig < 1) |
387 | return -EINVAL; |
388 | |
389 | spin_lock_irq(¤t->sighand->siglock); |
390 | /* This is only needed for daemonize()'ed kthreads */ |
391 | sigdelset(¤t->blocked, sig); |
392 | /* |
393 | * Kernel threads handle their own signals. Let the signal code |
394 | * know it'll be handled, so that they don't get converted to |
395 | * SIGKILL or just silently dropped. |
396 | */ |
397 | current->sighand->action[(sig)-1].sa.sa_handler = (void __user *)2; |
398 | recalc_sigpending(); |
399 | spin_unlock_irq(¤t->sighand->siglock); |
400 | return 0; |
401 | } |
402 | |
403 | EXPORT_SYMBOL(allow_signal); |
404 | |
405 | int disallow_signal(int sig) |
406 | { |
407 | if (!valid_signal(sig) || sig < 1) |
408 | return -EINVAL; |
409 | |
410 | spin_lock_irq(¤t->sighand->siglock); |
411 | current->sighand->action[(sig)-1].sa.sa_handler = SIG_IGN; |
412 | recalc_sigpending(); |
413 | spin_unlock_irq(¤t->sighand->siglock); |
414 | return 0; |
415 | } |
416 | |
417 | EXPORT_SYMBOL(disallow_signal); |
418 | |
419 | /* |
420 | * Put all the gunge required to become a kernel thread without |
421 | * attached user resources in one place where it belongs. |
422 | */ |
423 | |
424 | void daemonize(const char *name, ...) |
425 | { |
426 | va_list args; |
427 | sigset_t blocked; |
428 | |
429 | va_start(args, name); |
430 | vsnprintf(current->comm, sizeof(current->comm), name, args); |
431 | va_end(args); |
432 | |
433 | /* |
434 | * If we were started as result of loading a module, close all of the |
435 | * user space pages. We don't need them, and if we didn't close them |
436 | * they would be locked into memory. |
437 | */ |
438 | exit_mm(current); |
439 | /* |
440 | * We don't want to have TIF_FREEZE set if the system-wide hibernation |
441 | * or suspend transition begins right now. |
442 | */ |
443 | current->flags |= (PF_NOFREEZE | PF_KTHREAD); |
444 | |
445 | if (current->nsproxy != &init_nsproxy) { |
446 | get_nsproxy(&init_nsproxy); |
447 | switch_task_namespaces(current, &init_nsproxy); |
448 | } |
449 | set_special_pids(&init_struct_pid); |
450 | proc_clear_tty(current); |
451 | |
452 | /* Block and flush all signals */ |
453 | sigfillset(&blocked); |
454 | sigprocmask(SIG_BLOCK, &blocked, NULL); |
455 | flush_signals(current); |
456 | |
457 | /* Become as one with the init task */ |
458 | |
459 | daemonize_fs_struct(); |
460 | exit_files(current); |
461 | current->files = init_task.files; |
462 | atomic_inc(¤t->files->count); |
463 | |
464 | reparent_to_kthreadd(); |
465 | } |
466 | |
467 | EXPORT_SYMBOL(daemonize); |
468 | |
469 | static void close_files(struct files_struct * files) |
470 | { |
471 | int i, j; |
472 | struct fdtable *fdt; |
473 | |
474 | j = 0; |
475 | |
476 | /* |
477 | * It is safe to dereference the fd table without RCU or |
478 | * ->file_lock because this is the last reference to the |
479 | * files structure. But use RCU to shut RCU-lockdep up. |
480 | */ |
481 | rcu_read_lock(); |
482 | fdt = files_fdtable(files); |
483 | rcu_read_unlock(); |
484 | for (;;) { |
485 | unsigned long set; |
486 | i = j * __NFDBITS; |
487 | if (i >= fdt->max_fds) |
488 | break; |
489 | set = fdt->open_fds->fds_bits[j++]; |
490 | while (set) { |
491 | if (set & 1) { |
492 | struct file * file = xchg(&fdt->fd[i], NULL); |
493 | if (file) { |
494 | filp_close(file, files); |
495 | cond_resched(); |
496 | } |
497 | } |
498 | i++; |
499 | set >>= 1; |
500 | } |
501 | } |
502 | } |
503 | |
504 | struct files_struct *get_files_struct(struct task_struct *task) |
505 | { |
506 | struct files_struct *files; |
507 | |
508 | task_lock(task); |
509 | files = task->files; |
510 | if (files) |
511 | atomic_inc(&files->count); |
512 | task_unlock(task); |
513 | |
514 | return files; |
515 | } |
516 | |
517 | void put_files_struct(struct files_struct *files) |
518 | { |
519 | struct fdtable *fdt; |
520 | |
521 | if (atomic_dec_and_test(&files->count)) { |
522 | close_files(files); |
523 | /* |
524 | * Free the fd and fdset arrays if we expanded them. |
525 | * If the fdtable was embedded, pass files for freeing |
526 | * at the end of the RCU grace period. Otherwise, |
527 | * you can free files immediately. |
528 | */ |
529 | rcu_read_lock(); |
530 | fdt = files_fdtable(files); |
531 | if (fdt != &files->fdtab) |
532 | kmem_cache_free(files_cachep, files); |
533 | free_fdtable(fdt); |
534 | rcu_read_unlock(); |
535 | } |
536 | } |
537 | |
538 | void reset_files_struct(struct files_struct *files) |
539 | { |
540 | struct task_struct *tsk = current; |
541 | struct files_struct *old; |
542 | |
543 | old = tsk->files; |
544 | task_lock(tsk); |
545 | tsk->files = files; |
546 | task_unlock(tsk); |
547 | put_files_struct(old); |
548 | } |
549 | |
550 | void exit_files(struct task_struct *tsk) |
551 | { |
552 | struct files_struct * files = tsk->files; |
553 | |
554 | if (files) { |
555 | task_lock(tsk); |
556 | tsk->files = NULL; |
557 | task_unlock(tsk); |
558 | put_files_struct(files); |
559 | } |
560 | } |
561 | |
562 | #ifdef CONFIG_MM_OWNER |
563 | /* |
564 | * Task p is exiting and it owned mm, lets find a new owner for it |
565 | */ |
566 | static inline int |
567 | mm_need_new_owner(struct mm_struct *mm, struct task_struct *p) |
568 | { |
569 | /* |
570 | * If there are other users of the mm and the owner (us) is exiting |
571 | * we need to find a new owner to take on the responsibility. |
572 | */ |
573 | if (atomic_read(&mm->mm_users) <= 1) |
574 | return 0; |
575 | if (mm->owner != p) |
576 | return 0; |
577 | return 1; |
578 | } |
579 | |
580 | void mm_update_next_owner(struct mm_struct *mm) |
581 | { |
582 | struct task_struct *c, *g, *p = current; |
583 | |
584 | retry: |
585 | if (!mm_need_new_owner(mm, p)) |
586 | return; |
587 | |
588 | read_lock(&tasklist_lock); |
589 | /* |
590 | * Search in the children |
591 | */ |
592 | list_for_each_entry(c, &p->children, sibling) { |
593 | if (c->mm == mm) |
594 | goto assign_new_owner; |
595 | } |
596 | |
597 | /* |
598 | * Search in the siblings |
599 | */ |
600 | list_for_each_entry(c, &p->real_parent->children, sibling) { |
601 | if (c->mm == mm) |
602 | goto assign_new_owner; |
603 | } |
604 | |
605 | /* |
606 | * Search through everything else. We should not get |
607 | * here often |
608 | */ |
609 | do_each_thread(g, c) { |
610 | if (c->mm == mm) |
611 | goto assign_new_owner; |
612 | } while_each_thread(g, c); |
613 | |
614 | read_unlock(&tasklist_lock); |
615 | /* |
616 | * We found no owner yet mm_users > 1: this implies that we are |
617 | * most likely racing with swapoff (try_to_unuse()) or /proc or |
618 | * ptrace or page migration (get_task_mm()). Mark owner as NULL. |
619 | */ |
620 | mm->owner = NULL; |
621 | return; |
622 | |
623 | assign_new_owner: |
624 | BUG_ON(c == p); |
625 | get_task_struct(c); |
626 | /* |
627 | * The task_lock protects c->mm from changing. |
628 | * We always want mm->owner->mm == mm |
629 | */ |
630 | task_lock(c); |
631 | /* |
632 | * Delay read_unlock() till we have the task_lock() |
633 | * to ensure that c does not slip away underneath us |
634 | */ |
635 | read_unlock(&tasklist_lock); |
636 | if (c->mm != mm) { |
637 | task_unlock(c); |
638 | put_task_struct(c); |
639 | goto retry; |
640 | } |
641 | mm->owner = c; |
642 | task_unlock(c); |
643 | put_task_struct(c); |
644 | } |
645 | #endif /* CONFIG_MM_OWNER */ |
646 | |
647 | /* |
648 | * Turn us into a lazy TLB process if we |
649 | * aren't already.. |
650 | */ |
651 | static void exit_mm(struct task_struct * tsk) |
652 | { |
653 | struct mm_struct *mm = tsk->mm; |
654 | struct core_state *core_state; |
655 | |
656 | mm_release(tsk, mm); |
657 | if (!mm) |
658 | return; |
659 | /* |
660 | * Serialize with any possible pending coredump. |
661 | * We must hold mmap_sem around checking core_state |
662 | * and clearing tsk->mm. The core-inducing thread |
663 | * will increment ->nr_threads for each thread in the |
664 | * group with ->mm != NULL. |
665 | */ |
666 | down_read(&mm->mmap_sem); |
667 | core_state = mm->core_state; |
668 | if (core_state) { |
669 | struct core_thread self; |
670 | up_read(&mm->mmap_sem); |
671 | |
672 | self.task = tsk; |
673 | self.next = xchg(&core_state->dumper.next, &self); |
674 | /* |
675 | * Implies mb(), the result of xchg() must be visible |
676 | * to core_state->dumper. |
677 | */ |
678 | if (atomic_dec_and_test(&core_state->nr_threads)) |
679 | complete(&core_state->startup); |
680 | |
681 | for (;;) { |
682 | set_task_state(tsk, TASK_UNINTERRUPTIBLE); |
683 | if (!self.task) /* see coredump_finish() */ |
684 | break; |
685 | schedule(); |
686 | } |
687 | __set_task_state(tsk, TASK_RUNNING); |
688 | down_read(&mm->mmap_sem); |
689 | } |
690 | atomic_inc(&mm->mm_count); |
691 | BUG_ON(mm != tsk->active_mm); |
692 | /* more a memory barrier than a real lock */ |
693 | task_lock(tsk); |
694 | tsk->mm = NULL; |
695 | up_read(&mm->mmap_sem); |
696 | enter_lazy_tlb(mm, current); |
697 | /* We don't want this task to be frozen prematurely */ |
698 | clear_freeze_flag(tsk); |
699 | if (tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) |
700 | atomic_dec(&mm->oom_disable_count); |
701 | task_unlock(tsk); |
702 | mm_update_next_owner(mm); |
703 | mmput(mm); |
704 | } |
705 | |
706 | /* |
707 | * When we die, we re-parent all our children. |
708 | * Try to give them to another thread in our thread |
709 | * group, and if no such member exists, give it to |
710 | * the child reaper process (ie "init") in our pid |
711 | * space. |
712 | */ |
713 | static struct task_struct *find_new_reaper(struct task_struct *father) |
714 | __releases(&tasklist_lock) |
715 | __acquires(&tasklist_lock) |
716 | { |
717 | struct pid_namespace *pid_ns = task_active_pid_ns(father); |
718 | struct task_struct *thread; |
719 | |
720 | thread = father; |
721 | while_each_thread(father, thread) { |
722 | if (thread->flags & PF_EXITING) |
723 | continue; |
724 | if (unlikely(pid_ns->child_reaper == father)) |
725 | pid_ns->child_reaper = thread; |
726 | return thread; |
727 | } |
728 | |
729 | if (unlikely(pid_ns->child_reaper == father)) { |
730 | write_unlock_irq(&tasklist_lock); |
731 | if (unlikely(pid_ns == &init_pid_ns)) |
732 | panic("Attempted to kill init!"); |
733 | |
734 | zap_pid_ns_processes(pid_ns); |
735 | write_lock_irq(&tasklist_lock); |
736 | /* |
737 | * We can not clear ->child_reaper or leave it alone. |
738 | * There may by stealth EXIT_DEAD tasks on ->children, |
739 | * forget_original_parent() must move them somewhere. |
740 | */ |
741 | pid_ns->child_reaper = init_pid_ns.child_reaper; |
742 | } |
743 | |
744 | return pid_ns->child_reaper; |
745 | } |
746 | |
747 | /* |
748 | * Any that need to be release_task'd are put on the @dead list. |
749 | */ |
750 | static void reparent_leader(struct task_struct *father, struct task_struct *p, |
751 | struct list_head *dead) |
752 | { |
753 | list_move_tail(&p->sibling, &p->real_parent->children); |
754 | |
755 | if (task_detached(p)) |
756 | return; |
757 | /* |
758 | * If this is a threaded reparent there is no need to |
759 | * notify anyone anything has happened. |
760 | */ |
761 | if (same_thread_group(p->real_parent, father)) |
762 | return; |
763 | |
764 | /* We don't want people slaying init. */ |
765 | p->exit_signal = SIGCHLD; |
766 | |
767 | /* If it has exited notify the new parent about this child's death. */ |
768 | if (!task_ptrace(p) && |
769 | p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) { |
770 | do_notify_parent(p, p->exit_signal); |
771 | if (task_detached(p)) { |
772 | p->exit_state = EXIT_DEAD; |
773 | list_move_tail(&p->sibling, dead); |
774 | } |
775 | } |
776 | |
777 | kill_orphaned_pgrp(p, father); |
778 | } |
779 | |
780 | static void forget_original_parent(struct task_struct *father) |
781 | { |
782 | struct task_struct *p, *n, *reaper; |
783 | LIST_HEAD(dead_children); |
784 | |
785 | write_lock_irq(&tasklist_lock); |
786 | /* |
787 | * Note that exit_ptrace() and find_new_reaper() might |
788 | * drop tasklist_lock and reacquire it. |
789 | */ |
790 | exit_ptrace(father); |
791 | reaper = find_new_reaper(father); |
792 | |
793 | list_for_each_entry_safe(p, n, &father->children, sibling) { |
794 | struct task_struct *t = p; |
795 | do { |
796 | t->real_parent = reaper; |
797 | if (t->parent == father) { |
798 | BUG_ON(task_ptrace(t)); |
799 | t->parent = t->real_parent; |
800 | } |
801 | if (t->pdeath_signal) |
802 | group_send_sig_info(t->pdeath_signal, |
803 | SEND_SIG_NOINFO, t); |
804 | } while_each_thread(p, t); |
805 | reparent_leader(father, p, &dead_children); |
806 | } |
807 | write_unlock_irq(&tasklist_lock); |
808 | |
809 | BUG_ON(!list_empty(&father->children)); |
810 | |
811 | list_for_each_entry_safe(p, n, &dead_children, sibling) { |
812 | list_del_init(&p->sibling); |
813 | release_task(p); |
814 | } |
815 | } |
816 | |
817 | /* |
818 | * Send signals to all our closest relatives so that they know |
819 | * to properly mourn us.. |
820 | */ |
821 | static void exit_notify(struct task_struct *tsk, int group_dead) |
822 | { |
823 | int signal; |
824 | void *cookie; |
825 | |
826 | /* |
827 | * This does two things: |
828 | * |
829 | * A. Make init inherit all the child processes |
830 | * B. Check to see if any process groups have become orphaned |
831 | * as a result of our exiting, and if they have any stopped |
832 | * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2) |
833 | */ |
834 | forget_original_parent(tsk); |
835 | exit_task_namespaces(tsk); |
836 | |
837 | write_lock_irq(&tasklist_lock); |
838 | if (group_dead) |
839 | kill_orphaned_pgrp(tsk->group_leader, NULL); |
840 | |
841 | /* Let father know we died |
842 | * |
843 | * Thread signals are configurable, but you aren't going to use |
844 | * that to send signals to arbitary processes. |
845 | * That stops right now. |
846 | * |
847 | * If the parent exec id doesn't match the exec id we saved |
848 | * when we started then we know the parent has changed security |
849 | * domain. |
850 | * |
851 | * If our self_exec id doesn't match our parent_exec_id then |
852 | * we have changed execution domain as these two values started |
853 | * the same after a fork. |
854 | */ |
855 | if (tsk->exit_signal != SIGCHLD && !task_detached(tsk) && |
856 | (tsk->parent_exec_id != tsk->real_parent->self_exec_id || |
857 | tsk->self_exec_id != tsk->parent_exec_id)) |
858 | tsk->exit_signal = SIGCHLD; |
859 | |
860 | signal = tracehook_notify_death(tsk, &cookie, group_dead); |
861 | if (signal >= 0) |
862 | signal = do_notify_parent(tsk, signal); |
863 | |
864 | tsk->exit_state = signal == DEATH_REAP ? EXIT_DEAD : EXIT_ZOMBIE; |
865 | |
866 | /* mt-exec, de_thread() is waiting for group leader */ |
867 | if (unlikely(tsk->signal->notify_count < 0)) |
868 | wake_up_process(tsk->signal->group_exit_task); |
869 | write_unlock_irq(&tasklist_lock); |
870 | |
871 | tracehook_report_death(tsk, signal, cookie, group_dead); |
872 | |
873 | /* If the process is dead, release it - nobody will wait for it */ |
874 | if (signal == DEATH_REAP) |
875 | release_task(tsk); |
876 | } |
877 | |
878 | #ifdef CONFIG_DEBUG_STACK_USAGE |
879 | static void check_stack_usage(void) |
880 | { |
881 | static DEFINE_SPINLOCK(low_water_lock); |
882 | static int lowest_to_date = THREAD_SIZE; |
883 | unsigned long free; |
884 | |
885 | free = stack_not_used(current); |
886 | |
887 | if (free >= lowest_to_date) |
888 | return; |
889 | |
890 | spin_lock(&low_water_lock); |
891 | if (free < lowest_to_date) { |
892 | printk(KERN_WARNING "%s used greatest stack depth: %lu bytes " |
893 | "left\n", |
894 | current->comm, free); |
895 | lowest_to_date = free; |
896 | } |
897 | spin_unlock(&low_water_lock); |
898 | } |
899 | #else |
900 | static inline void check_stack_usage(void) {} |
901 | #endif |
902 | |
903 | NORET_TYPE void do_exit(long code) |
904 | { |
905 | struct task_struct *tsk = current; |
906 | int group_dead; |
907 | |
908 | profile_task_exit(tsk); |
909 | |
910 | WARN_ON(atomic_read(&tsk->fs_excl)); |
911 | |
912 | if (unlikely(in_interrupt())) |
913 | panic("Aiee, killing interrupt handler!"); |
914 | if (unlikely(!tsk->pid)) |
915 | panic("Attempted to kill the idle task!"); |
916 | |
917 | /* |
918 | * If do_exit is called because this processes oopsed, it's possible |
919 | * that get_fs() was left as KERNEL_DS, so reset it to USER_DS before |
920 | * continuing. Amongst other possible reasons, this is to prevent |
921 | * mm_release()->clear_child_tid() from writing to a user-controlled |
922 | * kernel address. |
923 | */ |
924 | set_fs(USER_DS); |
925 | |
926 | tracehook_report_exit(&code); |
927 | |
928 | validate_creds_for_do_exit(tsk); |
929 | |
930 | /* |
931 | * We're taking recursive faults here in do_exit. Safest is to just |
932 | * leave this task alone and wait for reboot. |
933 | */ |
934 | if (unlikely(tsk->flags & PF_EXITING)) { |
935 | printk(KERN_ALERT |
936 | "Fixing recursive fault but reboot is needed!\n"); |
937 | /* |
938 | * We can do this unlocked here. The futex code uses |
939 | * this flag just to verify whether the pi state |
940 | * cleanup has been done or not. In the worst case it |
941 | * loops once more. We pretend that the cleanup was |
942 | * done as there is no way to return. Either the |
943 | * OWNER_DIED bit is set by now or we push the blocked |
944 | * task into the wait for ever nirwana as well. |
945 | */ |
946 | tsk->flags |= PF_EXITPIDONE; |
947 | set_current_state(TASK_UNINTERRUPTIBLE); |
948 | schedule(); |
949 | } |
950 | |
951 | exit_irq_thread(); |
952 | |
953 | exit_signals(tsk); /* sets PF_EXITING */ |
954 | /* |
955 | * tsk->flags are checked in the futex code to protect against |
956 | * an exiting task cleaning up the robust pi futexes. |
957 | */ |
958 | smp_mb(); |
959 | raw_spin_unlock_wait(&tsk->pi_lock); |
960 | |
961 | if (unlikely(in_atomic())) |
962 | printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", |
963 | current->comm, task_pid_nr(current), |
964 | preempt_count()); |
965 | |
966 | acct_update_integrals(tsk); |
967 | /* sync mm's RSS info before statistics gathering */ |
968 | if (tsk->mm) |
969 | sync_mm_rss(tsk, tsk->mm); |
970 | group_dead = atomic_dec_and_test(&tsk->signal->live); |
971 | if (group_dead) { |
972 | hrtimer_cancel(&tsk->signal->real_timer); |
973 | exit_itimers(tsk->signal); |
974 | if (tsk->mm) |
975 | setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm); |
976 | } |
977 | acct_collect(code, group_dead); |
978 | if (group_dead) |
979 | tty_audit_exit(); |
980 | if (unlikely(tsk->audit_context)) |
981 | audit_free(tsk); |
982 | |
983 | tsk->exit_code = code; |
984 | taskstats_exit(tsk, group_dead); |
985 | |
986 | exit_mm(tsk); |
987 | |
988 | if (group_dead) |
989 | acct_process(); |
990 | trace_sched_process_exit(tsk); |
991 | |
992 | exit_sem(tsk); |
993 | exit_files(tsk); |
994 | exit_fs(tsk); |
995 | check_stack_usage(); |
996 | exit_thread(); |
997 | |
998 | /* |
999 | * Flush inherited counters to the parent - before the parent |
1000 | * gets woken up by child-exit notifications. |
1001 | * |
1002 | * because of cgroup mode, must be called before cgroup_exit() |
1003 | */ |
1004 | perf_event_exit_task(tsk); |
1005 | |
1006 | cgroup_exit(tsk, 1); |
1007 | |
1008 | if (group_dead) |
1009 | disassociate_ctty(1); |
1010 | |
1011 | module_put(task_thread_info(tsk)->exec_domain->module); |
1012 | |
1013 | proc_exit_connector(tsk); |
1014 | |
1015 | /* |
1016 | * FIXME: do that only when needed, using sched_exit tracepoint |
1017 | */ |
1018 | flush_ptrace_hw_breakpoint(tsk); |
1019 | |
1020 | exit_notify(tsk, group_dead); |
1021 | #ifdef CONFIG_NUMA |
1022 | task_lock(tsk); |
1023 | mpol_put(tsk->mempolicy); |
1024 | tsk->mempolicy = NULL; |
1025 | task_unlock(tsk); |
1026 | #endif |
1027 | #ifdef CONFIG_FUTEX |
1028 | if (unlikely(current->pi_state_cache)) |
1029 | kfree(current->pi_state_cache); |
1030 | #endif |
1031 | /* |
1032 | * Make sure we are holding no locks: |
1033 | */ |
1034 | debug_check_no_locks_held(tsk); |
1035 | /* |
1036 | * We can do this unlocked here. The futex code uses this flag |
1037 | * just to verify whether the pi state cleanup has been done |
1038 | * or not. In the worst case it loops once more. |
1039 | */ |
1040 | tsk->flags |= PF_EXITPIDONE; |
1041 | |
1042 | if (tsk->io_context) |
1043 | exit_io_context(tsk); |
1044 | |
1045 | if (tsk->splice_pipe) |
1046 | __free_pipe_info(tsk->splice_pipe); |
1047 | |
1048 | validate_creds_for_do_exit(tsk); |
1049 | |
1050 | preempt_disable(); |
1051 | exit_rcu(); |
1052 | /* causes final put_task_struct in finish_task_switch(). */ |
1053 | tsk->state = TASK_DEAD; |
1054 | schedule(); |
1055 | BUG(); |
1056 | /* Avoid "noreturn function does return". */ |
1057 | for (;;) |
1058 | cpu_relax(); /* For when BUG is null */ |
1059 | } |
1060 | |
1061 | EXPORT_SYMBOL_GPL(do_exit); |
1062 | |
1063 | NORET_TYPE void complete_and_exit(struct completion *comp, long code) |
1064 | { |
1065 | if (comp) |
1066 | complete(comp); |
1067 | |
1068 | do_exit(code); |
1069 | } |
1070 | |
1071 | EXPORT_SYMBOL(complete_and_exit); |
1072 | |
1073 | SYSCALL_DEFINE1(exit, int, error_code) |
1074 | { |
1075 | do_exit((error_code&0xff)<<8); |
1076 | } |
1077 | |
1078 | /* |
1079 | * Take down every thread in the group. This is called by fatal signals |
1080 | * as well as by sys_exit_group (below). |
1081 | */ |
1082 | NORET_TYPE void |
1083 | do_group_exit(int exit_code) |
1084 | { |
1085 | struct signal_struct *sig = current->signal; |
1086 | |
1087 | BUG_ON(exit_code & 0x80); /* core dumps don't get here */ |
1088 | |
1089 | if (signal_group_exit(sig)) |
1090 | exit_code = sig->group_exit_code; |
1091 | else if (!thread_group_empty(current)) { |
1092 | struct sighand_struct *const sighand = current->sighand; |
1093 | spin_lock_irq(&sighand->siglock); |
1094 | if (signal_group_exit(sig)) |
1095 | /* Another thread got here before we took the lock. */ |
1096 | exit_code = sig->group_exit_code; |
1097 | else { |
1098 | sig->group_exit_code = exit_code; |
1099 | sig->flags = SIGNAL_GROUP_EXIT; |
1100 | zap_other_threads(current); |
1101 | } |
1102 | spin_unlock_irq(&sighand->siglock); |
1103 | } |
1104 | |
1105 | do_exit(exit_code); |
1106 | /* NOTREACHED */ |
1107 | } |
1108 | |
1109 | /* |
1110 | * this kills every thread in the thread group. Note that any externally |
1111 | * wait4()-ing process will get the correct exit code - even if this |
1112 | * thread is not the thread group leader. |
1113 | */ |
1114 | SYSCALL_DEFINE1(exit_group, int, error_code) |
1115 | { |
1116 | do_group_exit((error_code & 0xff) << 8); |
1117 | /* NOTREACHED */ |
1118 | return 0; |
1119 | } |
1120 | |
1121 | struct wait_opts { |
1122 | enum pid_type wo_type; |
1123 | int wo_flags; |
1124 | struct pid *wo_pid; |
1125 | |
1126 | struct siginfo __user *wo_info; |
1127 | int __user *wo_stat; |
1128 | struct rusage __user *wo_rusage; |
1129 | |
1130 | wait_queue_t child_wait; |
1131 | int notask_error; |
1132 | }; |
1133 | |
1134 | static inline |
1135 | struct pid *task_pid_type(struct task_struct *task, enum pid_type type) |
1136 | { |
1137 | if (type != PIDTYPE_PID) |
1138 | task = task->group_leader; |
1139 | return task->pids[type].pid; |
1140 | } |
1141 | |
1142 | static int eligible_pid(struct wait_opts *wo, struct task_struct *p) |
1143 | { |
1144 | return wo->wo_type == PIDTYPE_MAX || |
1145 | task_pid_type(p, wo->wo_type) == wo->wo_pid; |
1146 | } |
1147 | |
1148 | static int eligible_child(struct wait_opts *wo, struct task_struct *p) |
1149 | { |
1150 | if (!eligible_pid(wo, p)) |
1151 | return 0; |
1152 | /* Wait for all children (clone and not) if __WALL is set; |
1153 | * otherwise, wait for clone children *only* if __WCLONE is |
1154 | * set; otherwise, wait for non-clone children *only*. (Note: |
1155 | * A "clone" child here is one that reports to its parent |
1156 | * using a signal other than SIGCHLD.) */ |
1157 | if (((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE)) |
1158 | && !(wo->wo_flags & __WALL)) |
1159 | return 0; |
1160 | |
1161 | return 1; |
1162 | } |
1163 | |
1164 | static int wait_noreap_copyout(struct wait_opts *wo, struct task_struct *p, |
1165 | pid_t pid, uid_t uid, int why, int status) |
1166 | { |
1167 | struct siginfo __user *infop; |
1168 | int retval = wo->wo_rusage |
1169 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; |
1170 | |
1171 | put_task_struct(p); |
1172 | infop = wo->wo_info; |
1173 | if (infop) { |
1174 | if (!retval) |
1175 | retval = put_user(SIGCHLD, &infop->si_signo); |
1176 | if (!retval) |
1177 | retval = put_user(0, &infop->si_errno); |
1178 | if (!retval) |
1179 | retval = put_user((short)why, &infop->si_code); |
1180 | if (!retval) |
1181 | retval = put_user(pid, &infop->si_pid); |
1182 | if (!retval) |
1183 | retval = put_user(uid, &infop->si_uid); |
1184 | if (!retval) |
1185 | retval = put_user(status, &infop->si_status); |
1186 | } |
1187 | if (!retval) |
1188 | retval = pid; |
1189 | return retval; |
1190 | } |
1191 | |
1192 | /* |
1193 | * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold |
1194 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold |
1195 | * the lock and this task is uninteresting. If we return nonzero, we have |
1196 | * released the lock and the system call should return. |
1197 | */ |
1198 | static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p) |
1199 | { |
1200 | unsigned long state; |
1201 | int retval, status, traced; |
1202 | pid_t pid = task_pid_vnr(p); |
1203 | uid_t uid = __task_cred(p)->uid; |
1204 | struct siginfo __user *infop; |
1205 | |
1206 | if (!likely(wo->wo_flags & WEXITED)) |
1207 | return 0; |
1208 | |
1209 | if (unlikely(wo->wo_flags & WNOWAIT)) { |
1210 | int exit_code = p->exit_code; |
1211 | int why; |
1212 | |
1213 | get_task_struct(p); |
1214 | read_unlock(&tasklist_lock); |
1215 | if ((exit_code & 0x7f) == 0) { |
1216 | why = CLD_EXITED; |
1217 | status = exit_code >> 8; |
1218 | } else { |
1219 | why = (exit_code & 0x80) ? CLD_DUMPED : CLD_KILLED; |
1220 | status = exit_code & 0x7f; |
1221 | } |
1222 | return wait_noreap_copyout(wo, p, pid, uid, why, status); |
1223 | } |
1224 | |
1225 | /* |
1226 | * Try to move the task's state to DEAD |
1227 | * only one thread is allowed to do this: |
1228 | */ |
1229 | state = xchg(&p->exit_state, EXIT_DEAD); |
1230 | if (state != EXIT_ZOMBIE) { |
1231 | BUG_ON(state != EXIT_DEAD); |
1232 | return 0; |
1233 | } |
1234 | |
1235 | traced = ptrace_reparented(p); |
1236 | /* |
1237 | * It can be ptraced but not reparented, check |
1238 | * !task_detached() to filter out sub-threads. |
1239 | */ |
1240 | if (likely(!traced) && likely(!task_detached(p))) { |
1241 | struct signal_struct *psig; |
1242 | struct signal_struct *sig; |
1243 | unsigned long maxrss; |
1244 | cputime_t tgutime, tgstime; |
1245 | |
1246 | /* |
1247 | * The resource counters for the group leader are in its |
1248 | * own task_struct. Those for dead threads in the group |
1249 | * are in its signal_struct, as are those for the child |
1250 | * processes it has previously reaped. All these |
1251 | * accumulate in the parent's signal_struct c* fields. |
1252 | * |
1253 | * We don't bother to take a lock here to protect these |
1254 | * p->signal fields, because they are only touched by |
1255 | * __exit_signal, which runs with tasklist_lock |
1256 | * write-locked anyway, and so is excluded here. We do |
1257 | * need to protect the access to parent->signal fields, |
1258 | * as other threads in the parent group can be right |
1259 | * here reaping other children at the same time. |
1260 | * |
1261 | * We use thread_group_times() to get times for the thread |
1262 | * group, which consolidates times for all threads in the |
1263 | * group including the group leader. |
1264 | */ |
1265 | thread_group_times(p, &tgutime, &tgstime); |
1266 | spin_lock_irq(&p->real_parent->sighand->siglock); |
1267 | psig = p->real_parent->signal; |
1268 | sig = p->signal; |
1269 | psig->cutime = |
1270 | cputime_add(psig->cutime, |
1271 | cputime_add(tgutime, |
1272 | sig->cutime)); |
1273 | psig->cstime = |
1274 | cputime_add(psig->cstime, |
1275 | cputime_add(tgstime, |
1276 | sig->cstime)); |
1277 | psig->cgtime = |
1278 | cputime_add(psig->cgtime, |
1279 | cputime_add(p->gtime, |
1280 | cputime_add(sig->gtime, |
1281 | sig->cgtime))); |
1282 | psig->cmin_flt += |
1283 | p->min_flt + sig->min_flt + sig->cmin_flt; |
1284 | psig->cmaj_flt += |
1285 | p->maj_flt + sig->maj_flt + sig->cmaj_flt; |
1286 | psig->cnvcsw += |
1287 | p->nvcsw + sig->nvcsw + sig->cnvcsw; |
1288 | psig->cnivcsw += |
1289 | p->nivcsw + sig->nivcsw + sig->cnivcsw; |
1290 | psig->cinblock += |
1291 | task_io_get_inblock(p) + |
1292 | sig->inblock + sig->cinblock; |
1293 | psig->coublock += |
1294 | task_io_get_oublock(p) + |
1295 | sig->oublock + sig->coublock; |
1296 | maxrss = max(sig->maxrss, sig->cmaxrss); |
1297 | if (psig->cmaxrss < maxrss) |
1298 | psig->cmaxrss = maxrss; |
1299 | task_io_accounting_add(&psig->ioac, &p->ioac); |
1300 | task_io_accounting_add(&psig->ioac, &sig->ioac); |
1301 | spin_unlock_irq(&p->real_parent->sighand->siglock); |
1302 | } |
1303 | |
1304 | /* |
1305 | * Now we are sure this task is interesting, and no other |
1306 | * thread can reap it because we set its state to EXIT_DEAD. |
1307 | */ |
1308 | read_unlock(&tasklist_lock); |
1309 | |
1310 | retval = wo->wo_rusage |
1311 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; |
1312 | status = (p->signal->flags & SIGNAL_GROUP_EXIT) |
1313 | ? p->signal->group_exit_code : p->exit_code; |
1314 | if (!retval && wo->wo_stat) |
1315 | retval = put_user(status, wo->wo_stat); |
1316 | |
1317 | infop = wo->wo_info; |
1318 | if (!retval && infop) |
1319 | retval = put_user(SIGCHLD, &infop->si_signo); |
1320 | if (!retval && infop) |
1321 | retval = put_user(0, &infop->si_errno); |
1322 | if (!retval && infop) { |
1323 | int why; |
1324 | |
1325 | if ((status & 0x7f) == 0) { |
1326 | why = CLD_EXITED; |
1327 | status >>= 8; |
1328 | } else { |
1329 | why = (status & 0x80) ? CLD_DUMPED : CLD_KILLED; |
1330 | status &= 0x7f; |
1331 | } |
1332 | retval = put_user((short)why, &infop->si_code); |
1333 | if (!retval) |
1334 | retval = put_user(status, &infop->si_status); |
1335 | } |
1336 | if (!retval && infop) |
1337 | retval = put_user(pid, &infop->si_pid); |
1338 | if (!retval && infop) |
1339 | retval = put_user(uid, &infop->si_uid); |
1340 | if (!retval) |
1341 | retval = pid; |
1342 | |
1343 | if (traced) { |
1344 | write_lock_irq(&tasklist_lock); |
1345 | /* We dropped tasklist, ptracer could die and untrace */ |
1346 | ptrace_unlink(p); |
1347 | /* |
1348 | * If this is not a detached task, notify the parent. |
1349 | * If it's still not detached after that, don't release |
1350 | * it now. |
1351 | */ |
1352 | if (!task_detached(p)) { |
1353 | do_notify_parent(p, p->exit_signal); |
1354 | if (!task_detached(p)) { |
1355 | p->exit_state = EXIT_ZOMBIE; |
1356 | p = NULL; |
1357 | } |
1358 | } |
1359 | write_unlock_irq(&tasklist_lock); |
1360 | } |
1361 | if (p != NULL) |
1362 | release_task(p); |
1363 | |
1364 | return retval; |
1365 | } |
1366 | |
1367 | static int *task_stopped_code(struct task_struct *p, bool ptrace) |
1368 | { |
1369 | if (ptrace) { |
1370 | if (task_is_stopped_or_traced(p)) |
1371 | return &p->exit_code; |
1372 | } else { |
1373 | if (p->signal->flags & SIGNAL_STOP_STOPPED) |
1374 | return &p->signal->group_exit_code; |
1375 | } |
1376 | return NULL; |
1377 | } |
1378 | |
1379 | /* |
1380 | * Handle sys_wait4 work for one task in state TASK_STOPPED. We hold |
1381 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold |
1382 | * the lock and this task is uninteresting. If we return nonzero, we have |
1383 | * released the lock and the system call should return. |
1384 | */ |
1385 | static int wait_task_stopped(struct wait_opts *wo, |
1386 | int ptrace, struct task_struct *p) |
1387 | { |
1388 | struct siginfo __user *infop; |
1389 | int retval, exit_code, *p_code, why; |
1390 | uid_t uid = 0; /* unneeded, required by compiler */ |
1391 | pid_t pid; |
1392 | |
1393 | /* |
1394 | * Traditionally we see ptrace'd stopped tasks regardless of options. |
1395 | */ |
1396 | if (!ptrace && !(wo->wo_flags & WUNTRACED)) |
1397 | return 0; |
1398 | |
1399 | exit_code = 0; |
1400 | spin_lock_irq(&p->sighand->siglock); |
1401 | |
1402 | p_code = task_stopped_code(p, ptrace); |
1403 | if (unlikely(!p_code)) |
1404 | goto unlock_sig; |
1405 | |
1406 | exit_code = *p_code; |
1407 | if (!exit_code) |
1408 | goto unlock_sig; |
1409 | |
1410 | if (!unlikely(wo->wo_flags & WNOWAIT)) |
1411 | *p_code = 0; |
1412 | |
1413 | uid = task_uid(p); |
1414 | unlock_sig: |
1415 | spin_unlock_irq(&p->sighand->siglock); |
1416 | if (!exit_code) |
1417 | return 0; |
1418 | |
1419 | /* |
1420 | * Now we are pretty sure this task is interesting. |
1421 | * Make sure it doesn't get reaped out from under us while we |
1422 | * give up the lock and then examine it below. We don't want to |
1423 | * keep holding onto the tasklist_lock while we call getrusage and |
1424 | * possibly take page faults for user memory. |
1425 | */ |
1426 | get_task_struct(p); |
1427 | pid = task_pid_vnr(p); |
1428 | why = ptrace ? CLD_TRAPPED : CLD_STOPPED; |
1429 | read_unlock(&tasklist_lock); |
1430 | |
1431 | if (unlikely(wo->wo_flags & WNOWAIT)) |
1432 | return wait_noreap_copyout(wo, p, pid, uid, why, exit_code); |
1433 | |
1434 | retval = wo->wo_rusage |
1435 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; |
1436 | if (!retval && wo->wo_stat) |
1437 | retval = put_user((exit_code << 8) | 0x7f, wo->wo_stat); |
1438 | |
1439 | infop = wo->wo_info; |
1440 | if (!retval && infop) |
1441 | retval = put_user(SIGCHLD, &infop->si_signo); |
1442 | if (!retval && infop) |
1443 | retval = put_user(0, &infop->si_errno); |
1444 | if (!retval && infop) |
1445 | retval = put_user((short)why, &infop->si_code); |
1446 | if (!retval && infop) |
1447 | retval = put_user(exit_code, &infop->si_status); |
1448 | if (!retval && infop) |
1449 | retval = put_user(pid, &infop->si_pid); |
1450 | if (!retval && infop) |
1451 | retval = put_user(uid, &infop->si_uid); |
1452 | if (!retval) |
1453 | retval = pid; |
1454 | put_task_struct(p); |
1455 | |
1456 | BUG_ON(!retval); |
1457 | return retval; |
1458 | } |
1459 | |
1460 | /* |
1461 | * Handle do_wait work for one task in a live, non-stopped state. |
1462 | * read_lock(&tasklist_lock) on entry. If we return zero, we still hold |
1463 | * the lock and this task is uninteresting. If we return nonzero, we have |
1464 | * released the lock and the system call should return. |
1465 | */ |
1466 | static int wait_task_continued(struct wait_opts *wo, struct task_struct *p) |
1467 | { |
1468 | int retval; |
1469 | pid_t pid; |
1470 | uid_t uid; |
1471 | |
1472 | if (!unlikely(wo->wo_flags & WCONTINUED)) |
1473 | return 0; |
1474 | |
1475 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) |
1476 | return 0; |
1477 | |
1478 | spin_lock_irq(&p->sighand->siglock); |
1479 | /* Re-check with the lock held. */ |
1480 | if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) { |
1481 | spin_unlock_irq(&p->sighand->siglock); |
1482 | return 0; |
1483 | } |
1484 | if (!unlikely(wo->wo_flags & WNOWAIT)) |
1485 | p->signal->flags &= ~SIGNAL_STOP_CONTINUED; |
1486 | uid = task_uid(p); |
1487 | spin_unlock_irq(&p->sighand->siglock); |
1488 | |
1489 | pid = task_pid_vnr(p); |
1490 | get_task_struct(p); |
1491 | read_unlock(&tasklist_lock); |
1492 | |
1493 | if (!wo->wo_info) { |
1494 | retval = wo->wo_rusage |
1495 | ? getrusage(p, RUSAGE_BOTH, wo->wo_rusage) : 0; |
1496 | put_task_struct(p); |
1497 | if (!retval && wo->wo_stat) |
1498 | retval = put_user(0xffff, wo->wo_stat); |
1499 | if (!retval) |
1500 | retval = pid; |
1501 | } else { |
1502 | retval = wait_noreap_copyout(wo, p, pid, uid, |
1503 | CLD_CONTINUED, SIGCONT); |
1504 | BUG_ON(retval == 0); |
1505 | } |
1506 | |
1507 | return retval; |
1508 | } |
1509 | |
1510 | /* |
1511 | * Consider @p for a wait by @parent. |
1512 | * |
1513 | * -ECHILD should be in ->notask_error before the first call. |
1514 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. |
1515 | * Returns zero if the search for a child should continue; |
1516 | * then ->notask_error is 0 if @p is an eligible child, |
1517 | * or another error from security_task_wait(), or still -ECHILD. |
1518 | */ |
1519 | static int wait_consider_task(struct wait_opts *wo, int ptrace, |
1520 | struct task_struct *p) |
1521 | { |
1522 | int ret = eligible_child(wo, p); |
1523 | if (!ret) |
1524 | return ret; |
1525 | |
1526 | ret = security_task_wait(p); |
1527 | if (unlikely(ret < 0)) { |
1528 | /* |
1529 | * If we have not yet seen any eligible child, |
1530 | * then let this error code replace -ECHILD. |
1531 | * A permission error will give the user a clue |
1532 | * to look for security policy problems, rather |
1533 | * than for mysterious wait bugs. |
1534 | */ |
1535 | if (wo->notask_error) |
1536 | wo->notask_error = ret; |
1537 | return 0; |
1538 | } |
1539 | |
1540 | if (likely(!ptrace) && unlikely(task_ptrace(p))) { |
1541 | /* |
1542 | * This child is hidden by ptrace. |
1543 | * We aren't allowed to see it now, but eventually we will. |
1544 | */ |
1545 | wo->notask_error = 0; |
1546 | return 0; |
1547 | } |
1548 | |
1549 | if (p->exit_state == EXIT_DEAD) |
1550 | return 0; |
1551 | |
1552 | /* |
1553 | * We don't reap group leaders with subthreads. |
1554 | */ |
1555 | if (p->exit_state == EXIT_ZOMBIE && !delay_group_leader(p)) |
1556 | return wait_task_zombie(wo, p); |
1557 | |
1558 | /* |
1559 | * It's stopped or running now, so it might |
1560 | * later continue, exit, or stop again. |
1561 | */ |
1562 | wo->notask_error = 0; |
1563 | |
1564 | if (task_stopped_code(p, ptrace)) |
1565 | return wait_task_stopped(wo, ptrace, p); |
1566 | |
1567 | return wait_task_continued(wo, p); |
1568 | } |
1569 | |
1570 | /* |
1571 | * Do the work of do_wait() for one thread in the group, @tsk. |
1572 | * |
1573 | * -ECHILD should be in ->notask_error before the first call. |
1574 | * Returns nonzero for a final return, when we have unlocked tasklist_lock. |
1575 | * Returns zero if the search for a child should continue; then |
1576 | * ->notask_error is 0 if there were any eligible children, |
1577 | * or another error from security_task_wait(), or still -ECHILD. |
1578 | */ |
1579 | static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk) |
1580 | { |
1581 | struct task_struct *p; |
1582 | |
1583 | list_for_each_entry(p, &tsk->children, sibling) { |
1584 | int ret = wait_consider_task(wo, 0, p); |
1585 | if (ret) |
1586 | return ret; |
1587 | } |
1588 | |
1589 | return 0; |
1590 | } |
1591 | |
1592 | static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk) |
1593 | { |
1594 | struct task_struct *p; |
1595 | |
1596 | list_for_each_entry(p, &tsk->ptraced, ptrace_entry) { |
1597 | int ret = wait_consider_task(wo, 1, p); |
1598 | if (ret) |
1599 | return ret; |
1600 | } |
1601 | |
1602 | return 0; |
1603 | } |
1604 | |
1605 | static int child_wait_callback(wait_queue_t *wait, unsigned mode, |
1606 | int sync, void *key) |
1607 | { |
1608 | struct wait_opts *wo = container_of(wait, struct wait_opts, |
1609 | child_wait); |
1610 | struct task_struct *p = key; |
1611 | |
1612 | if (!eligible_pid(wo, p)) |
1613 | return 0; |
1614 | |
1615 | if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent) |
1616 | return 0; |
1617 | |
1618 | return default_wake_function(wait, mode, sync, key); |
1619 | } |
1620 | |
1621 | void __wake_up_parent(struct task_struct *p, struct task_struct *parent) |
1622 | { |
1623 | __wake_up_sync_key(&parent->signal->wait_chldexit, |
1624 | TASK_INTERRUPTIBLE, 1, p); |
1625 | } |
1626 | |
1627 | static long do_wait(struct wait_opts *wo) |
1628 | { |
1629 | struct task_struct *tsk; |
1630 | int retval; |
1631 | |
1632 | trace_sched_process_wait(wo->wo_pid); |
1633 | |
1634 | init_waitqueue_func_entry(&wo->child_wait, child_wait_callback); |
1635 | wo->child_wait.private = current; |
1636 | add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait); |
1637 | repeat: |
1638 | /* |
1639 | * If there is nothing that can match our critiera just get out. |
1640 | * We will clear ->notask_error to zero if we see any child that |
1641 | * might later match our criteria, even if we are not able to reap |
1642 | * it yet. |
1643 | */ |
1644 | wo->notask_error = -ECHILD; |
1645 | if ((wo->wo_type < PIDTYPE_MAX) && |
1646 | (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type]))) |
1647 | goto notask; |
1648 | |
1649 | set_current_state(TASK_INTERRUPTIBLE); |
1650 | read_lock(&tasklist_lock); |
1651 | tsk = current; |
1652 | do { |
1653 | retval = do_wait_thread(wo, tsk); |
1654 | if (retval) |
1655 | goto end; |
1656 | |
1657 | retval = ptrace_do_wait(wo, tsk); |
1658 | if (retval) |
1659 | goto end; |
1660 | |
1661 | if (wo->wo_flags & __WNOTHREAD) |
1662 | break; |
1663 | } while_each_thread(current, tsk); |
1664 | read_unlock(&tasklist_lock); |
1665 | |
1666 | notask: |
1667 | retval = wo->notask_error; |
1668 | if (!retval && !(wo->wo_flags & WNOHANG)) { |
1669 | retval = -ERESTARTSYS; |
1670 | if (!signal_pending(current)) { |
1671 | schedule(); |
1672 | goto repeat; |
1673 | } |
1674 | } |
1675 | end: |
1676 | __set_current_state(TASK_RUNNING); |
1677 | remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait); |
1678 | return retval; |
1679 | } |
1680 | |
1681 | SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *, |
1682 | infop, int, options, struct rusage __user *, ru) |
1683 | { |
1684 | struct wait_opts wo; |
1685 | struct pid *pid = NULL; |
1686 | enum pid_type type; |
1687 | long ret; |
1688 | |
1689 | if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED)) |
1690 | return -EINVAL; |
1691 | if (!(options & (WEXITED|WSTOPPED|WCONTINUED))) |
1692 | return -EINVAL; |
1693 | |
1694 | switch (which) { |
1695 | case P_ALL: |
1696 | type = PIDTYPE_MAX; |
1697 | break; |
1698 | case P_PID: |
1699 | type = PIDTYPE_PID; |
1700 | if (upid <= 0) |
1701 | return -EINVAL; |
1702 | break; |
1703 | case P_PGID: |
1704 | type = PIDTYPE_PGID; |
1705 | if (upid <= 0) |
1706 | return -EINVAL; |
1707 | break; |
1708 | default: |
1709 | return -EINVAL; |
1710 | } |
1711 | |
1712 | if (type < PIDTYPE_MAX) |
1713 | pid = find_get_pid(upid); |
1714 | |
1715 | wo.wo_type = type; |
1716 | wo.wo_pid = pid; |
1717 | wo.wo_flags = options; |
1718 | wo.wo_info = infop; |
1719 | wo.wo_stat = NULL; |
1720 | wo.wo_rusage = ru; |
1721 | ret = do_wait(&wo); |
1722 | |
1723 | if (ret > 0) { |
1724 | ret = 0; |
1725 | } else if (infop) { |
1726 | /* |
1727 | * For a WNOHANG return, clear out all the fields |
1728 | * we would set so the user can easily tell the |
1729 | * difference. |
1730 | */ |
1731 | if (!ret) |
1732 | ret = put_user(0, &infop->si_signo); |
1733 | if (!ret) |
1734 | ret = put_user(0, &infop->si_errno); |
1735 | if (!ret) |
1736 | ret = put_user(0, &infop->si_code); |
1737 | if (!ret) |
1738 | ret = put_user(0, &infop->si_pid); |
1739 | if (!ret) |
1740 | ret = put_user(0, &infop->si_uid); |
1741 | if (!ret) |
1742 | ret = put_user(0, &infop->si_status); |
1743 | } |
1744 | |
1745 | put_pid(pid); |
1746 | |
1747 | /* avoid REGPARM breakage on x86: */ |
1748 | asmlinkage_protect(5, ret, which, upid, infop, options, ru); |
1749 | return ret; |
1750 | } |
1751 | |
1752 | SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr, |
1753 | int, options, struct rusage __user *, ru) |
1754 | { |
1755 | struct wait_opts wo; |
1756 | struct pid *pid = NULL; |
1757 | enum pid_type type; |
1758 | long ret; |
1759 | |
1760 | if (options & ~(WNOHANG|WUNTRACED|WCONTINUED| |
1761 | __WNOTHREAD|__WCLONE|__WALL)) |
1762 | return -EINVAL; |
1763 | |
1764 | if (upid == -1) |
1765 | type = PIDTYPE_MAX; |
1766 | else if (upid < 0) { |
1767 | type = PIDTYPE_PGID; |
1768 | pid = find_get_pid(-upid); |
1769 | } else if (upid == 0) { |
1770 | type = PIDTYPE_PGID; |
1771 | pid = get_task_pid(current, PIDTYPE_PGID); |
1772 | } else /* upid > 0 */ { |
1773 | type = PIDTYPE_PID; |
1774 | pid = find_get_pid(upid); |
1775 | } |
1776 | |
1777 | wo.wo_type = type; |
1778 | wo.wo_pid = pid; |
1779 | wo.wo_flags = options | WEXITED; |
1780 | wo.wo_info = NULL; |
1781 | wo.wo_stat = stat_addr; |
1782 | wo.wo_rusage = ru; |
1783 | ret = do_wait(&wo); |
1784 | put_pid(pid); |
1785 | |
1786 | /* avoid REGPARM breakage on x86: */ |
1787 | asmlinkage_protect(4, ret, upid, stat_addr, options, ru); |
1788 | return ret; |
1789 | } |
1790 | |
1791 | #ifdef __ARCH_WANT_SYS_WAITPID |
1792 | |
1793 | /* |
1794 | * sys_waitpid() remains for compatibility. waitpid() should be |
1795 | * implemented by calling sys_wait4() from libc.a. |
1796 | */ |
1797 | SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options) |
1798 | { |
1799 | return sys_wait4(pid, stat_addr, options, NULL); |
1800 | } |
1801 | |
1802 | #endif |
1803 |
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javiroman/ks7010
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jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9