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6
7
8#include <linux/mm.h>
9#include <linux/slab.h>
10#include <linux/sched/autogroup.h>
11#include <linux/sched/mm.h>
12#include <linux/sched/stat.h>
13#include <linux/sched/task.h>
14#include <linux/sched/task_stack.h>
15#include <linux/sched/cputime.h>
16#include <linux/interrupt.h>
17#include <linux/module.h>
18#include <linux/capability.h>
19#include <linux/completion.h>
20#include <linux/personality.h>
21#include <linux/tty.h>
22#include <linux/iocontext.h>
23#include <linux/key.h>
24#include <linux/cpu.h>
25#include <linux/acct.h>
26#include <linux/tsacct_kern.h>
27#include <linux/file.h>
28#include <linux/fdtable.h>
29#include <linux/freezer.h>
30#include <linux/binfmts.h>
31#include <linux/nsproxy.h>
32#include <linux/pid_namespace.h>
33#include <linux/ptrace.h>
34#include <linux/profile.h>
35#include <linux/mount.h>
36#include <linux/proc_fs.h>
37#include <linux/kthread.h>
38#include <linux/mempolicy.h>
39#include <linux/taskstats_kern.h>
40#include <linux/delayacct.h>
41#include <linux/cgroup.h>
42#include <linux/syscalls.h>
43#include <linux/signal.h>
44#include <linux/posix-timers.h>
45#include <linux/cn_proc.h>
46#include <linux/mutex.h>
47#include <linux/futex.h>
48#include <linux/pipe_fs_i.h>
49#include <linux/audit.h>
50#include <linux/resource.h>
51#include <linux/blkdev.h>
52#include <linux/task_io_accounting_ops.h>
53#include <linux/tracehook.h>
54#include <linux/fs_struct.h>
55#include <linux/init_task.h>
56#include <linux/perf_event.h>
57#include <trace/events/sched.h>
58#include <linux/hw_breakpoint.h>
59#include <linux/oom.h>
60#include <linux/writeback.h>
61#include <linux/shm.h>
62#include <linux/kcov.h>
63#include <linux/random.h>
64#include <linux/rcuwait.h>
65#include <linux/compat.h>
66#include <linux/io_uring.h>
67
68#include <linux/uaccess.h>
69#include <asm/unistd.h>
70#include <asm/mmu_context.h>
71
72static void __unhash_process(struct task_struct *p, bool group_dead)
73{
74 nr_threads--;
75 detach_pid(p, PIDTYPE_PID);
76 if (group_dead) {
77 detach_pid(p, PIDTYPE_TGID);
78 detach_pid(p, PIDTYPE_PGID);
79 detach_pid(p, PIDTYPE_SID);
80
81 list_del_rcu(&p->tasks);
82 list_del_init(&p->sibling);
83 __this_cpu_dec(process_counts);
84 }
85 list_del_rcu(&p->thread_group);
86 list_del_rcu(&p->thread_node);
87}
88
89
90
91
92static void __exit_signal(struct task_struct *tsk)
93{
94 struct signal_struct *sig = tsk->signal;
95 bool group_dead = thread_group_leader(tsk);
96 struct sighand_struct *sighand;
97 struct tty_struct *tty;
98 u64 utime, stime;
99
100 sighand = rcu_dereference_check(tsk->sighand,
101 lockdep_tasklist_lock_is_held());
102 spin_lock(&sighand->siglock);
103
104#ifdef CONFIG_POSIX_TIMERS
105 posix_cpu_timers_exit(tsk);
106 if (group_dead)
107 posix_cpu_timers_exit_group(tsk);
108#endif
109
110 if (group_dead) {
111 tty = sig->tty;
112 sig->tty = NULL;
113 } else {
114
115
116
117
118 if (sig->notify_count > 0 && !--sig->notify_count)
119 wake_up_process(sig->group_exit_task);
120
121 if (tsk == sig->curr_target)
122 sig->curr_target = next_thread(tsk);
123 }
124
125 add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
126 sizeof(unsigned long long));
127
128
129
130
131
132
133
134 task_cputime(tsk, &utime, &stime);
135 write_seqlock(&sig->stats_lock);
136 sig->utime += utime;
137 sig->stime += stime;
138 sig->gtime += task_gtime(tsk);
139 sig->min_flt += tsk->min_flt;
140 sig->maj_flt += tsk->maj_flt;
141 sig->nvcsw += tsk->nvcsw;
142 sig->nivcsw += tsk->nivcsw;
143 sig->inblock += task_io_get_inblock(tsk);
144 sig->oublock += task_io_get_oublock(tsk);
145 task_io_accounting_add(&sig->ioac, &tsk->ioac);
146 sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
147 sig->nr_threads--;
148 __unhash_process(tsk, group_dead);
149 write_sequnlock(&sig->stats_lock);
150
151
152
153
154
155 flush_sigqueue(&tsk->pending);
156 tsk->sighand = NULL;
157 spin_unlock(&sighand->siglock);
158
159 __cleanup_sighand(sighand);
160 clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
161 if (group_dead) {
162 flush_sigqueue(&sig->shared_pending);
163 tty_kref_put(tty);
164 }
165}
166
167static void delayed_put_task_struct(struct rcu_head *rhp)
168{
169 struct task_struct *tsk = container_of(rhp, struct task_struct, rcu);
170
171 perf_event_delayed_put(tsk);
172 trace_sched_process_free(tsk);
173 put_task_struct(tsk);
174}
175
176void put_task_struct_rcu_user(struct task_struct *task)
177{
178 if (refcount_dec_and_test(&task->rcu_users))
179 call_rcu(&task->rcu, delayed_put_task_struct);
180}
181
182void release_task(struct task_struct *p)
183{
184 struct task_struct *leader;
185 struct pid *thread_pid;
186 int zap_leader;
187repeat:
188
189
190 rcu_read_lock();
191 dec_rlimit_ucounts(task_ucounts(p), UCOUNT_RLIMIT_NPROC, 1);
192 rcu_read_unlock();
193
194 cgroup_release(p);
195
196 write_lock_irq(&tasklist_lock);
197 ptrace_release_task(p);
198 thread_pid = get_pid(p->thread_pid);
199 __exit_signal(p);
200
201
202
203
204
205
206 zap_leader = 0;
207 leader = p->group_leader;
208 if (leader != p && thread_group_empty(leader)
209 && leader->exit_state == EXIT_ZOMBIE) {
210
211
212
213
214
215 zap_leader = do_notify_parent(leader, leader->exit_signal);
216 if (zap_leader)
217 leader->exit_state = EXIT_DEAD;
218 }
219
220 write_unlock_irq(&tasklist_lock);
221 seccomp_filter_release(p);
222 proc_flush_pid(thread_pid);
223 put_pid(thread_pid);
224 release_thread(p);
225 put_task_struct_rcu_user(p);
226
227 p = leader;
228 if (unlikely(zap_leader))
229 goto repeat;
230}
231
232int rcuwait_wake_up(struct rcuwait *w)
233{
234 int ret = 0;
235 struct task_struct *task;
236
237 rcu_read_lock();
238
239
240
241
242
243
244
245
246
247
248
249
250 smp_mb();
251
252 task = rcu_dereference(w->task);
253 if (task)
254 ret = wake_up_process(task);
255 rcu_read_unlock();
256
257 return ret;
258}
259EXPORT_SYMBOL_GPL(rcuwait_wake_up);
260
261
262
263
264
265
266
267
268
269static int will_become_orphaned_pgrp(struct pid *pgrp,
270 struct task_struct *ignored_task)
271{
272 struct task_struct *p;
273
274 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
275 if ((p == ignored_task) ||
276 (p->exit_state && thread_group_empty(p)) ||
277 is_global_init(p->real_parent))
278 continue;
279
280 if (task_pgrp(p->real_parent) != pgrp &&
281 task_session(p->real_parent) == task_session(p))
282 return 0;
283 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
284
285 return 1;
286}
287
288int is_current_pgrp_orphaned(void)
289{
290 int retval;
291
292 read_lock(&tasklist_lock);
293 retval = will_become_orphaned_pgrp(task_pgrp(current), NULL);
294 read_unlock(&tasklist_lock);
295
296 return retval;
297}
298
299static bool has_stopped_jobs(struct pid *pgrp)
300{
301 struct task_struct *p;
302
303 do_each_pid_task(pgrp, PIDTYPE_PGID, p) {
304 if (p->signal->flags & SIGNAL_STOP_STOPPED)
305 return true;
306 } while_each_pid_task(pgrp, PIDTYPE_PGID, p);
307
308 return false;
309}
310
311
312
313
314
315
316static void
317kill_orphaned_pgrp(struct task_struct *tsk, struct task_struct *parent)
318{
319 struct pid *pgrp = task_pgrp(tsk);
320 struct task_struct *ignored_task = tsk;
321
322 if (!parent)
323
324
325
326 parent = tsk->real_parent;
327 else
328
329
330
331 ignored_task = NULL;
332
333 if (task_pgrp(parent) != pgrp &&
334 task_session(parent) == task_session(tsk) &&
335 will_become_orphaned_pgrp(pgrp, ignored_task) &&
336 has_stopped_jobs(pgrp)) {
337 __kill_pgrp_info(SIGHUP, SEND_SIG_PRIV, pgrp);
338 __kill_pgrp_info(SIGCONT, SEND_SIG_PRIV, pgrp);
339 }
340}
341
342#ifdef CONFIG_MEMCG
343
344
345
346void mm_update_next_owner(struct mm_struct *mm)
347{
348 struct task_struct *c, *g, *p = current;
349
350retry:
351
352
353
354
355 if (mm->owner != p)
356 return;
357
358
359
360
361
362 if (atomic_read(&mm->mm_users) <= 1) {
363 WRITE_ONCE(mm->owner, NULL);
364 return;
365 }
366
367 read_lock(&tasklist_lock);
368
369
370
371 list_for_each_entry(c, &p->children, sibling) {
372 if (c->mm == mm)
373 goto assign_new_owner;
374 }
375
376
377
378
379 list_for_each_entry(c, &p->real_parent->children, sibling) {
380 if (c->mm == mm)
381 goto assign_new_owner;
382 }
383
384
385
386
387 for_each_process(g) {
388 if (g->flags & PF_KTHREAD)
389 continue;
390 for_each_thread(g, c) {
391 if (c->mm == mm)
392 goto assign_new_owner;
393 if (c->mm)
394 break;
395 }
396 }
397 read_unlock(&tasklist_lock);
398
399
400
401
402
403 WRITE_ONCE(mm->owner, NULL);
404 return;
405
406assign_new_owner:
407 BUG_ON(c == p);
408 get_task_struct(c);
409
410
411
412
413 task_lock(c);
414
415
416
417
418 read_unlock(&tasklist_lock);
419 if (c->mm != mm) {
420 task_unlock(c);
421 put_task_struct(c);
422 goto retry;
423 }
424 WRITE_ONCE(mm->owner, c);
425 task_unlock(c);
426 put_task_struct(c);
427}
428#endif
429
430
431
432
433
434static void exit_mm(void)
435{
436 struct mm_struct *mm = current->mm;
437 struct core_state *core_state;
438
439 exit_mm_release(current, mm);
440 if (!mm)
441 return;
442 sync_mm_rss(mm);
443
444
445
446
447
448
449
450 mmap_read_lock(mm);
451 core_state = mm->core_state;
452 if (core_state) {
453 struct core_thread self;
454
455 mmap_read_unlock(mm);
456
457 self.task = current;
458 if (self.task->flags & PF_SIGNALED)
459 self.next = xchg(&core_state->dumper.next, &self);
460 else
461 self.task = NULL;
462
463
464
465
466 if (atomic_dec_and_test(&core_state->nr_threads))
467 complete(&core_state->startup);
468
469 for (;;) {
470 set_current_state(TASK_UNINTERRUPTIBLE);
471 if (!self.task)
472 break;
473 freezable_schedule();
474 }
475 __set_current_state(TASK_RUNNING);
476 mmap_read_lock(mm);
477 }
478 mmgrab(mm);
479 BUG_ON(mm != current->active_mm);
480
481 task_lock(current);
482
483
484
485
486
487
488
489
490
491
492 smp_mb__after_spinlock();
493 local_irq_disable();
494 current->mm = NULL;
495 membarrier_update_current_mm(NULL);
496 enter_lazy_tlb(mm, current);
497 local_irq_enable();
498 task_unlock(current);
499 mmap_read_unlock(mm);
500 mm_update_next_owner(mm);
501 mmput(mm);
502 if (test_thread_flag(TIF_MEMDIE))
503 exit_oom_victim();
504}
505
506static struct task_struct *find_alive_thread(struct task_struct *p)
507{
508 struct task_struct *t;
509
510 for_each_thread(p, t) {
511 if (!(t->flags & PF_EXITING))
512 return t;
513 }
514 return NULL;
515}
516
517static struct task_struct *find_child_reaper(struct task_struct *father,
518 struct list_head *dead)
519 __releases(&tasklist_lock)
520 __acquires(&tasklist_lock)
521{
522 struct pid_namespace *pid_ns = task_active_pid_ns(father);
523 struct task_struct *reaper = pid_ns->child_reaper;
524 struct task_struct *p, *n;
525
526 if (likely(reaper != father))
527 return reaper;
528
529 reaper = find_alive_thread(father);
530 if (reaper) {
531 pid_ns->child_reaper = reaper;
532 return reaper;
533 }
534
535 write_unlock_irq(&tasklist_lock);
536
537 list_for_each_entry_safe(p, n, dead, ptrace_entry) {
538 list_del_init(&p->ptrace_entry);
539 release_task(p);
540 }
541
542 zap_pid_ns_processes(pid_ns);
543 write_lock_irq(&tasklist_lock);
544
545 return father;
546}
547
548
549
550
551
552
553
554
555static struct task_struct *find_new_reaper(struct task_struct *father,
556 struct task_struct *child_reaper)
557{
558 struct task_struct *thread, *reaper;
559
560 thread = find_alive_thread(father);
561 if (thread)
562 return thread;
563
564 if (father->signal->has_child_subreaper) {
565 unsigned int ns_level = task_pid(father)->level;
566
567
568
569
570
571
572
573
574 for (reaper = father->real_parent;
575 task_pid(reaper)->level == ns_level;
576 reaper = reaper->real_parent) {
577 if (reaper == &init_task)
578 break;
579 if (!reaper->signal->is_child_subreaper)
580 continue;
581 thread = find_alive_thread(reaper);
582 if (thread)
583 return thread;
584 }
585 }
586
587 return child_reaper;
588}
589
590
591
592
593static void reparent_leader(struct task_struct *father, struct task_struct *p,
594 struct list_head *dead)
595{
596 if (unlikely(p->exit_state == EXIT_DEAD))
597 return;
598
599
600 p->exit_signal = SIGCHLD;
601
602
603 if (!p->ptrace &&
604 p->exit_state == EXIT_ZOMBIE && thread_group_empty(p)) {
605 if (do_notify_parent(p, p->exit_signal)) {
606 p->exit_state = EXIT_DEAD;
607 list_add(&p->ptrace_entry, dead);
608 }
609 }
610
611 kill_orphaned_pgrp(p, father);
612}
613
614
615
616
617
618
619
620
621
622static void forget_original_parent(struct task_struct *father,
623 struct list_head *dead)
624{
625 struct task_struct *p, *t, *reaper;
626
627 if (unlikely(!list_empty(&father->ptraced)))
628 exit_ptrace(father, dead);
629
630
631 reaper = find_child_reaper(father, dead);
632 if (list_empty(&father->children))
633 return;
634
635 reaper = find_new_reaper(father, reaper);
636 list_for_each_entry(p, &father->children, sibling) {
637 for_each_thread(p, t) {
638 RCU_INIT_POINTER(t->real_parent, reaper);
639 BUG_ON((!t->ptrace) != (rcu_access_pointer(t->parent) == father));
640 if (likely(!t->ptrace))
641 t->parent = t->real_parent;
642 if (t->pdeath_signal)
643 group_send_sig_info(t->pdeath_signal,
644 SEND_SIG_NOINFO, t,
645 PIDTYPE_TGID);
646 }
647
648
649
650
651 if (!same_thread_group(reaper, father))
652 reparent_leader(father, p, dead);
653 }
654 list_splice_tail_init(&father->children, &reaper->children);
655}
656
657
658
659
660
661static void exit_notify(struct task_struct *tsk, int group_dead)
662{
663 bool autoreap;
664 struct task_struct *p, *n;
665 LIST_HEAD(dead);
666
667 write_lock_irq(&tasklist_lock);
668 forget_original_parent(tsk, &dead);
669
670 if (group_dead)
671 kill_orphaned_pgrp(tsk->group_leader, NULL);
672
673 tsk->exit_state = EXIT_ZOMBIE;
674 if (unlikely(tsk->ptrace)) {
675 int sig = thread_group_leader(tsk) &&
676 thread_group_empty(tsk) &&
677 !ptrace_reparented(tsk) ?
678 tsk->exit_signal : SIGCHLD;
679 autoreap = do_notify_parent(tsk, sig);
680 } else if (thread_group_leader(tsk)) {
681 autoreap = thread_group_empty(tsk) &&
682 do_notify_parent(tsk, tsk->exit_signal);
683 } else {
684 autoreap = true;
685 }
686
687 if (autoreap) {
688 tsk->exit_state = EXIT_DEAD;
689 list_add(&tsk->ptrace_entry, &dead);
690 }
691
692
693 if (unlikely(tsk->signal->notify_count < 0))
694 wake_up_process(tsk->signal->group_exit_task);
695 write_unlock_irq(&tasklist_lock);
696
697 list_for_each_entry_safe(p, n, &dead, ptrace_entry) {
698 list_del_init(&p->ptrace_entry);
699 release_task(p);
700 }
701}
702
703#ifdef CONFIG_DEBUG_STACK_USAGE
704static void check_stack_usage(void)
705{
706 static DEFINE_SPINLOCK(low_water_lock);
707 static int lowest_to_date = THREAD_SIZE;
708 unsigned long free;
709
710 free = stack_not_used(current);
711
712 if (free >= lowest_to_date)
713 return;
714
715 spin_lock(&low_water_lock);
716 if (free < lowest_to_date) {
717 pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
718 current->comm, task_pid_nr(current), free);
719 lowest_to_date = free;
720 }
721 spin_unlock(&low_water_lock);
722}
723#else
724static inline void check_stack_usage(void) {}
725#endif
726
727void __noreturn do_exit(long code)
728{
729 struct task_struct *tsk = current;
730 int group_dead;
731
732
733
734
735
736
737
738
739 WARN_ON(blk_needs_flush_plug(tsk));
740
741 if (unlikely(in_interrupt()))
742 panic("Aiee, killing interrupt handler!");
743 if (unlikely(!tsk->pid))
744 panic("Attempted to kill the idle task!");
745
746
747
748
749
750
751
752
753 force_uaccess_begin();
754
755 if (unlikely(in_atomic())) {
756 pr_info("note: %s[%d] exited with preempt_count %d\n",
757 current->comm, task_pid_nr(current),
758 preempt_count());
759 preempt_count_set(PREEMPT_ENABLED);
760 }
761
762 profile_task_exit(tsk);
763 kcov_task_exit(tsk);
764
765 ptrace_event(PTRACE_EVENT_EXIT, code);
766
767 validate_creds_for_do_exit(tsk);
768
769
770
771
772
773 if (unlikely(tsk->flags & PF_EXITING)) {
774 pr_alert("Fixing recursive fault but reboot is needed!\n");
775 futex_exit_recursive(tsk);
776 set_current_state(TASK_UNINTERRUPTIBLE);
777 schedule();
778 }
779
780 io_uring_files_cancel(tsk->files);
781 exit_signals(tsk);
782
783
784 if (tsk->mm)
785 sync_mm_rss(tsk->mm);
786 acct_update_integrals(tsk);
787 group_dead = atomic_dec_and_test(&tsk->signal->live);
788 if (group_dead) {
789
790
791
792
793 if (unlikely(is_global_init(tsk)))
794 panic("Attempted to kill init! exitcode=0x%08x\n",
795 tsk->signal->group_exit_code ?: (int)code);
796
797#ifdef CONFIG_POSIX_TIMERS
798 hrtimer_cancel(&tsk->signal->real_timer);
799 exit_itimers(tsk->signal);
800#endif
801 if (tsk->mm)
802 setmax_mm_hiwater_rss(&tsk->signal->maxrss, tsk->mm);
803 }
804 acct_collect(code, group_dead);
805 if (group_dead)
806 tty_audit_exit();
807 audit_free(tsk);
808
809 tsk->exit_code = code;
810 taskstats_exit(tsk, group_dead);
811
812 exit_mm();
813
814 if (group_dead)
815 acct_process();
816 trace_sched_process_exit(tsk);
817
818 exit_sem(tsk);
819 exit_shm(tsk);
820 exit_files(tsk);
821 exit_fs(tsk);
822 if (group_dead)
823 disassociate_ctty(1);
824 exit_task_namespaces(tsk);
825 exit_task_work(tsk);
826 exit_thread(tsk);
827
828
829
830
831
832
833
834 perf_event_exit_task(tsk);
835
836 sched_autogroup_exit_task(tsk);
837 cgroup_exit(tsk);
838
839
840
841
842 flush_ptrace_hw_breakpoint(tsk);
843
844 exit_tasks_rcu_start();
845 exit_notify(tsk, group_dead);
846 proc_exit_connector(tsk);
847 mpol_put_task_policy(tsk);
848#ifdef CONFIG_FUTEX
849 if (unlikely(current->pi_state_cache))
850 kfree(current->pi_state_cache);
851#endif
852
853
854
855 debug_check_no_locks_held();
856
857 if (tsk->io_context)
858 exit_io_context(tsk);
859
860 if (tsk->splice_pipe)
861 free_pipe_info(tsk->splice_pipe);
862
863 if (tsk->task_frag.page)
864 put_page(tsk->task_frag.page);
865
866 validate_creds_for_do_exit(tsk);
867
868 check_stack_usage();
869 preempt_disable();
870 if (tsk->nr_dirtied)
871 __this_cpu_add(dirty_throttle_leaks, tsk->nr_dirtied);
872 exit_rcu();
873 exit_tasks_rcu_finish();
874
875 lockdep_free_task(tsk);
876 do_task_dead();
877}
878EXPORT_SYMBOL_GPL(do_exit);
879
880void complete_and_exit(struct completion *comp, long code)
881{
882 if (comp)
883 complete(comp);
884
885 do_exit(code);
886}
887EXPORT_SYMBOL(complete_and_exit);
888
889SYSCALL_DEFINE1(exit, int, error_code)
890{
891 do_exit((error_code&0xff)<<8);
892}
893
894
895
896
897
898void
899do_group_exit(int exit_code)
900{
901 struct signal_struct *sig = current->signal;
902
903 BUG_ON(exit_code & 0x80);
904
905 if (signal_group_exit(sig))
906 exit_code = sig->group_exit_code;
907 else if (!thread_group_empty(current)) {
908 struct sighand_struct *const sighand = current->sighand;
909
910 spin_lock_irq(&sighand->siglock);
911 if (signal_group_exit(sig))
912
913 exit_code = sig->group_exit_code;
914 else {
915 sig->group_exit_code = exit_code;
916 sig->flags = SIGNAL_GROUP_EXIT;
917 zap_other_threads(current);
918 }
919 spin_unlock_irq(&sighand->siglock);
920 }
921
922 do_exit(exit_code);
923
924}
925
926
927
928
929
930
931SYSCALL_DEFINE1(exit_group, int, error_code)
932{
933 do_group_exit((error_code & 0xff) << 8);
934
935 return 0;
936}
937
938struct waitid_info {
939 pid_t pid;
940 uid_t uid;
941 int status;
942 int cause;
943};
944
945struct wait_opts {
946 enum pid_type wo_type;
947 int wo_flags;
948 struct pid *wo_pid;
949
950 struct waitid_info *wo_info;
951 int wo_stat;
952 struct rusage *wo_rusage;
953
954 wait_queue_entry_t child_wait;
955 int notask_error;
956};
957
958static int eligible_pid(struct wait_opts *wo, struct task_struct *p)
959{
960 return wo->wo_type == PIDTYPE_MAX ||
961 task_pid_type(p, wo->wo_type) == wo->wo_pid;
962}
963
964static int
965eligible_child(struct wait_opts *wo, bool ptrace, struct task_struct *p)
966{
967 if (!eligible_pid(wo, p))
968 return 0;
969
970
971
972
973
974 if (ptrace || (wo->wo_flags & __WALL))
975 return 1;
976
977
978
979
980
981
982
983
984
985 if ((p->exit_signal != SIGCHLD) ^ !!(wo->wo_flags & __WCLONE))
986 return 0;
987
988 return 1;
989}
990
991
992
993
994
995
996
997static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
998{
999 int state, status;
1000 pid_t pid = task_pid_vnr(p);
1001 uid_t uid = from_kuid_munged(current_user_ns(), task_uid(p));
1002 struct waitid_info *infop;
1003
1004 if (!likely(wo->wo_flags & WEXITED))
1005 return 0;
1006
1007 if (unlikely(wo->wo_flags & WNOWAIT)) {
1008 status = p->exit_code;
1009 get_task_struct(p);
1010 read_unlock(&tasklist_lock);
1011 sched_annotate_sleep();
1012 if (wo->wo_rusage)
1013 getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
1014 put_task_struct(p);
1015 goto out_info;
1016 }
1017
1018
1019
1020 state = (ptrace_reparented(p) && thread_group_leader(p)) ?
1021 EXIT_TRACE : EXIT_DEAD;
1022 if (cmpxchg(&p->exit_state, EXIT_ZOMBIE, state) != EXIT_ZOMBIE)
1023 return 0;
1024
1025
1026
1027 read_unlock(&tasklist_lock);
1028 sched_annotate_sleep();
1029
1030
1031
1032
1033 if (state == EXIT_DEAD && thread_group_leader(p)) {
1034 struct signal_struct *sig = p->signal;
1035 struct signal_struct *psig = current->signal;
1036 unsigned long maxrss;
1037 u64 tgutime, tgstime;
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059 thread_group_cputime_adjusted(p, &tgutime, &tgstime);
1060 spin_lock_irq(¤t->sighand->siglock);
1061 write_seqlock(&psig->stats_lock);
1062 psig->cutime += tgutime + sig->cutime;
1063 psig->cstime += tgstime + sig->cstime;
1064 psig->cgtime += task_gtime(p) + sig->gtime + sig->cgtime;
1065 psig->cmin_flt +=
1066 p->min_flt + sig->min_flt + sig->cmin_flt;
1067 psig->cmaj_flt +=
1068 p->maj_flt + sig->maj_flt + sig->cmaj_flt;
1069 psig->cnvcsw +=
1070 p->nvcsw + sig->nvcsw + sig->cnvcsw;
1071 psig->cnivcsw +=
1072 p->nivcsw + sig->nivcsw + sig->cnivcsw;
1073 psig->cinblock +=
1074 task_io_get_inblock(p) +
1075 sig->inblock + sig->cinblock;
1076 psig->coublock +=
1077 task_io_get_oublock(p) +
1078 sig->oublock + sig->coublock;
1079 maxrss = max(sig->maxrss, sig->cmaxrss);
1080 if (psig->cmaxrss < maxrss)
1081 psig->cmaxrss = maxrss;
1082 task_io_accounting_add(&psig->ioac, &p->ioac);
1083 task_io_accounting_add(&psig->ioac, &sig->ioac);
1084 write_sequnlock(&psig->stats_lock);
1085 spin_unlock_irq(¤t->sighand->siglock);
1086 }
1087
1088 if (wo->wo_rusage)
1089 getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
1090 status = (p->signal->flags & SIGNAL_GROUP_EXIT)
1091 ? p->signal->group_exit_code : p->exit_code;
1092 wo->wo_stat = status;
1093
1094 if (state == EXIT_TRACE) {
1095 write_lock_irq(&tasklist_lock);
1096
1097 ptrace_unlink(p);
1098
1099
1100 state = EXIT_ZOMBIE;
1101 if (do_notify_parent(p, p->exit_signal))
1102 state = EXIT_DEAD;
1103 p->exit_state = state;
1104 write_unlock_irq(&tasklist_lock);
1105 }
1106 if (state == EXIT_DEAD)
1107 release_task(p);
1108
1109out_info:
1110 infop = wo->wo_info;
1111 if (infop) {
1112 if ((status & 0x7f) == 0) {
1113 infop->cause = CLD_EXITED;
1114 infop->status = status >> 8;
1115 } else {
1116 infop->cause = (status & 0x80) ? CLD_DUMPED : CLD_KILLED;
1117 infop->status = status & 0x7f;
1118 }
1119 infop->pid = pid;
1120 infop->uid = uid;
1121 }
1122
1123 return pid;
1124}
1125
1126static int *task_stopped_code(struct task_struct *p, bool ptrace)
1127{
1128 if (ptrace) {
1129 if (task_is_traced(p) && !(p->jobctl & JOBCTL_LISTENING))
1130 return &p->exit_code;
1131 } else {
1132 if (p->signal->flags & SIGNAL_STOP_STOPPED)
1133 return &p->signal->group_exit_code;
1134 }
1135 return NULL;
1136}
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156static int wait_task_stopped(struct wait_opts *wo,
1157 int ptrace, struct task_struct *p)
1158{
1159 struct waitid_info *infop;
1160 int exit_code, *p_code, why;
1161 uid_t uid = 0;
1162 pid_t pid;
1163
1164
1165
1166
1167 if (!ptrace && !(wo->wo_flags & WUNTRACED))
1168 return 0;
1169
1170 if (!task_stopped_code(p, ptrace))
1171 return 0;
1172
1173 exit_code = 0;
1174 spin_lock_irq(&p->sighand->siglock);
1175
1176 p_code = task_stopped_code(p, ptrace);
1177 if (unlikely(!p_code))
1178 goto unlock_sig;
1179
1180 exit_code = *p_code;
1181 if (!exit_code)
1182 goto unlock_sig;
1183
1184 if (!unlikely(wo->wo_flags & WNOWAIT))
1185 *p_code = 0;
1186
1187 uid = from_kuid_munged(current_user_ns(), task_uid(p));
1188unlock_sig:
1189 spin_unlock_irq(&p->sighand->siglock);
1190 if (!exit_code)
1191 return 0;
1192
1193
1194
1195
1196
1197
1198
1199
1200 get_task_struct(p);
1201 pid = task_pid_vnr(p);
1202 why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
1203 read_unlock(&tasklist_lock);
1204 sched_annotate_sleep();
1205 if (wo->wo_rusage)
1206 getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
1207 put_task_struct(p);
1208
1209 if (likely(!(wo->wo_flags & WNOWAIT)))
1210 wo->wo_stat = (exit_code << 8) | 0x7f;
1211
1212 infop = wo->wo_info;
1213 if (infop) {
1214 infop->cause = why;
1215 infop->status = exit_code;
1216 infop->pid = pid;
1217 infop->uid = uid;
1218 }
1219 return pid;
1220}
1221
1222
1223
1224
1225
1226
1227
1228static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
1229{
1230 struct waitid_info *infop;
1231 pid_t pid;
1232 uid_t uid;
1233
1234 if (!unlikely(wo->wo_flags & WCONTINUED))
1235 return 0;
1236
1237 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED))
1238 return 0;
1239
1240 spin_lock_irq(&p->sighand->siglock);
1241
1242 if (!(p->signal->flags & SIGNAL_STOP_CONTINUED)) {
1243 spin_unlock_irq(&p->sighand->siglock);
1244 return 0;
1245 }
1246 if (!unlikely(wo->wo_flags & WNOWAIT))
1247 p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
1248 uid = from_kuid_munged(current_user_ns(), task_uid(p));
1249 spin_unlock_irq(&p->sighand->siglock);
1250
1251 pid = task_pid_vnr(p);
1252 get_task_struct(p);
1253 read_unlock(&tasklist_lock);
1254 sched_annotate_sleep();
1255 if (wo->wo_rusage)
1256 getrusage(p, RUSAGE_BOTH, wo->wo_rusage);
1257 put_task_struct(p);
1258
1259 infop = wo->wo_info;
1260 if (!infop) {
1261 wo->wo_stat = 0xffff;
1262 } else {
1263 infop->cause = CLD_CONTINUED;
1264 infop->pid = pid;
1265 infop->uid = uid;
1266 infop->status = SIGCONT;
1267 }
1268 return pid;
1269}
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280static int wait_consider_task(struct wait_opts *wo, int ptrace,
1281 struct task_struct *p)
1282{
1283
1284
1285
1286
1287
1288 int exit_state = READ_ONCE(p->exit_state);
1289 int ret;
1290
1291 if (unlikely(exit_state == EXIT_DEAD))
1292 return 0;
1293
1294 ret = eligible_child(wo, ptrace, p);
1295 if (!ret)
1296 return ret;
1297
1298 if (unlikely(exit_state == EXIT_TRACE)) {
1299
1300
1301
1302
1303 if (likely(!ptrace))
1304 wo->notask_error = 0;
1305 return 0;
1306 }
1307
1308 if (likely(!ptrace) && unlikely(p->ptrace)) {
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320 if (!ptrace_reparented(p))
1321 ptrace = 1;
1322 }
1323
1324
1325 if (exit_state == EXIT_ZOMBIE) {
1326
1327 if (!delay_group_leader(p)) {
1328
1329
1330
1331
1332
1333 if (unlikely(ptrace) || likely(!p->ptrace))
1334 return wait_task_zombie(wo, p);
1335 }
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357 if (likely(!ptrace) || (wo->wo_flags & (WCONTINUED | WEXITED)))
1358 wo->notask_error = 0;
1359 } else {
1360
1361
1362
1363
1364 wo->notask_error = 0;
1365 }
1366
1367
1368
1369
1370
1371 ret = wait_task_stopped(wo, ptrace, p);
1372 if (ret)
1373 return ret;
1374
1375
1376
1377
1378
1379
1380 return wait_task_continued(wo, p);
1381}
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392static int do_wait_thread(struct wait_opts *wo, struct task_struct *tsk)
1393{
1394 struct task_struct *p;
1395
1396 list_for_each_entry(p, &tsk->children, sibling) {
1397 int ret = wait_consider_task(wo, 0, p);
1398
1399 if (ret)
1400 return ret;
1401 }
1402
1403 return 0;
1404}
1405
1406static int ptrace_do_wait(struct wait_opts *wo, struct task_struct *tsk)
1407{
1408 struct task_struct *p;
1409
1410 list_for_each_entry(p, &tsk->ptraced, ptrace_entry) {
1411 int ret = wait_consider_task(wo, 1, p);
1412
1413 if (ret)
1414 return ret;
1415 }
1416
1417 return 0;
1418}
1419
1420static int child_wait_callback(wait_queue_entry_t *wait, unsigned mode,
1421 int sync, void *key)
1422{
1423 struct wait_opts *wo = container_of(wait, struct wait_opts,
1424 child_wait);
1425 struct task_struct *p = key;
1426
1427 if (!eligible_pid(wo, p))
1428 return 0;
1429
1430 if ((wo->wo_flags & __WNOTHREAD) && wait->private != p->parent)
1431 return 0;
1432
1433 return default_wake_function(wait, mode, sync, key);
1434}
1435
1436void __wake_up_parent(struct task_struct *p, struct task_struct *parent)
1437{
1438 __wake_up_sync_key(&parent->signal->wait_chldexit,
1439 TASK_INTERRUPTIBLE, p);
1440}
1441
1442static bool is_effectively_child(struct wait_opts *wo, bool ptrace,
1443 struct task_struct *target)
1444{
1445 struct task_struct *parent =
1446 !ptrace ? target->real_parent : target->parent;
1447
1448 return current == parent || (!(wo->wo_flags & __WNOTHREAD) &&
1449 same_thread_group(current, parent));
1450}
1451
1452
1453
1454
1455
1456static int do_wait_pid(struct wait_opts *wo)
1457{
1458 bool ptrace;
1459 struct task_struct *target;
1460 int retval;
1461
1462 ptrace = false;
1463 target = pid_task(wo->wo_pid, PIDTYPE_TGID);
1464 if (target && is_effectively_child(wo, ptrace, target)) {
1465 retval = wait_consider_task(wo, ptrace, target);
1466 if (retval)
1467 return retval;
1468 }
1469
1470 ptrace = true;
1471 target = pid_task(wo->wo_pid, PIDTYPE_PID);
1472 if (target && target->ptrace &&
1473 is_effectively_child(wo, ptrace, target)) {
1474 retval = wait_consider_task(wo, ptrace, target);
1475 if (retval)
1476 return retval;
1477 }
1478
1479 return 0;
1480}
1481
1482static long do_wait(struct wait_opts *wo)
1483{
1484 int retval;
1485
1486 trace_sched_process_wait(wo->wo_pid);
1487
1488 init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
1489 wo->child_wait.private = current;
1490 add_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
1491repeat:
1492
1493
1494
1495
1496
1497
1498 wo->notask_error = -ECHILD;
1499 if ((wo->wo_type < PIDTYPE_MAX) &&
1500 (!wo->wo_pid || !pid_has_task(wo->wo_pid, wo->wo_type)))
1501 goto notask;
1502
1503 set_current_state(TASK_INTERRUPTIBLE);
1504 read_lock(&tasklist_lock);
1505
1506 if (wo->wo_type == PIDTYPE_PID) {
1507 retval = do_wait_pid(wo);
1508 if (retval)
1509 goto end;
1510 } else {
1511 struct task_struct *tsk = current;
1512
1513 do {
1514 retval = do_wait_thread(wo, tsk);
1515 if (retval)
1516 goto end;
1517
1518 retval = ptrace_do_wait(wo, tsk);
1519 if (retval)
1520 goto end;
1521
1522 if (wo->wo_flags & __WNOTHREAD)
1523 break;
1524 } while_each_thread(current, tsk);
1525 }
1526 read_unlock(&tasklist_lock);
1527
1528notask:
1529 retval = wo->notask_error;
1530 if (!retval && !(wo->wo_flags & WNOHANG)) {
1531 retval = -ERESTARTSYS;
1532 if (!signal_pending(current)) {
1533 schedule();
1534 goto repeat;
1535 }
1536 }
1537end:
1538 __set_current_state(TASK_RUNNING);
1539 remove_wait_queue(¤t->signal->wait_chldexit, &wo->child_wait);
1540 return retval;
1541}
1542
1543static long kernel_waitid(int which, pid_t upid, struct waitid_info *infop,
1544 int options, struct rusage *ru)
1545{
1546 struct wait_opts wo;
1547 struct pid *pid = NULL;
1548 enum pid_type type;
1549 long ret;
1550 unsigned int f_flags = 0;
1551
1552 if (options & ~(WNOHANG|WNOWAIT|WEXITED|WSTOPPED|WCONTINUED|
1553 __WNOTHREAD|__WCLONE|__WALL))
1554 return -EINVAL;
1555 if (!(options & (WEXITED|WSTOPPED|WCONTINUED)))
1556 return -EINVAL;
1557
1558 switch (which) {
1559 case P_ALL:
1560 type = PIDTYPE_MAX;
1561 break;
1562 case P_PID:
1563 type = PIDTYPE_PID;
1564 if (upid <= 0)
1565 return -EINVAL;
1566
1567 pid = find_get_pid(upid);
1568 break;
1569 case P_PGID:
1570 type = PIDTYPE_PGID;
1571 if (upid < 0)
1572 return -EINVAL;
1573
1574 if (upid)
1575 pid = find_get_pid(upid);
1576 else
1577 pid = get_task_pid(current, PIDTYPE_PGID);
1578 break;
1579 case P_PIDFD:
1580 type = PIDTYPE_PID;
1581 if (upid < 0)
1582 return -EINVAL;
1583
1584 pid = pidfd_get_pid(upid, &f_flags);
1585 if (IS_ERR(pid))
1586 return PTR_ERR(pid);
1587
1588 break;
1589 default:
1590 return -EINVAL;
1591 }
1592
1593 wo.wo_type = type;
1594 wo.wo_pid = pid;
1595 wo.wo_flags = options;
1596 wo.wo_info = infop;
1597 wo.wo_rusage = ru;
1598 if (f_flags & O_NONBLOCK)
1599 wo.wo_flags |= WNOHANG;
1600
1601 ret = do_wait(&wo);
1602 if (!ret && !(options & WNOHANG) && (f_flags & O_NONBLOCK))
1603 ret = -EAGAIN;
1604
1605 put_pid(pid);
1606 return ret;
1607}
1608
1609SYSCALL_DEFINE5(waitid, int, which, pid_t, upid, struct siginfo __user *,
1610 infop, int, options, struct rusage __user *, ru)
1611{
1612 struct rusage r;
1613 struct waitid_info info = {.status = 0};
1614 long err = kernel_waitid(which, upid, &info, options, ru ? &r : NULL);
1615 int signo = 0;
1616
1617 if (err > 0) {
1618 signo = SIGCHLD;
1619 err = 0;
1620 if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
1621 return -EFAULT;
1622 }
1623 if (!infop)
1624 return err;
1625
1626 if (!user_write_access_begin(infop, sizeof(*infop)))
1627 return -EFAULT;
1628
1629 unsafe_put_user(signo, &infop->si_signo, Efault);
1630 unsafe_put_user(0, &infop->si_errno, Efault);
1631 unsafe_put_user(info.cause, &infop->si_code, Efault);
1632 unsafe_put_user(info.pid, &infop->si_pid, Efault);
1633 unsafe_put_user(info.uid, &infop->si_uid, Efault);
1634 unsafe_put_user(info.status, &infop->si_status, Efault);
1635 user_write_access_end();
1636 return err;
1637Efault:
1638 user_write_access_end();
1639 return -EFAULT;
1640}
1641
1642long kernel_wait4(pid_t upid, int __user *stat_addr, int options,
1643 struct rusage *ru)
1644{
1645 struct wait_opts wo;
1646 struct pid *pid = NULL;
1647 enum pid_type type;
1648 long ret;
1649
1650 if (options & ~(WNOHANG|WUNTRACED|WCONTINUED|
1651 __WNOTHREAD|__WCLONE|__WALL))
1652 return -EINVAL;
1653
1654
1655 if (upid == INT_MIN)
1656 return -ESRCH;
1657
1658 if (upid == -1)
1659 type = PIDTYPE_MAX;
1660 else if (upid < 0) {
1661 type = PIDTYPE_PGID;
1662 pid = find_get_pid(-upid);
1663 } else if (upid == 0) {
1664 type = PIDTYPE_PGID;
1665 pid = get_task_pid(current, PIDTYPE_PGID);
1666 } else {
1667 type = PIDTYPE_PID;
1668 pid = find_get_pid(upid);
1669 }
1670
1671 wo.wo_type = type;
1672 wo.wo_pid = pid;
1673 wo.wo_flags = options | WEXITED;
1674 wo.wo_info = NULL;
1675 wo.wo_stat = 0;
1676 wo.wo_rusage = ru;
1677 ret = do_wait(&wo);
1678 put_pid(pid);
1679 if (ret > 0 && stat_addr && put_user(wo.wo_stat, stat_addr))
1680 ret = -EFAULT;
1681
1682 return ret;
1683}
1684
1685int kernel_wait(pid_t pid, int *stat)
1686{
1687 struct wait_opts wo = {
1688 .wo_type = PIDTYPE_PID,
1689 .wo_pid = find_get_pid(pid),
1690 .wo_flags = WEXITED,
1691 };
1692 int ret;
1693
1694 ret = do_wait(&wo);
1695 if (ret > 0 && wo.wo_stat)
1696 *stat = wo.wo_stat;
1697 put_pid(wo.wo_pid);
1698 return ret;
1699}
1700
1701SYSCALL_DEFINE4(wait4, pid_t, upid, int __user *, stat_addr,
1702 int, options, struct rusage __user *, ru)
1703{
1704 struct rusage r;
1705 long err = kernel_wait4(upid, stat_addr, options, ru ? &r : NULL);
1706
1707 if (err > 0) {
1708 if (ru && copy_to_user(ru, &r, sizeof(struct rusage)))
1709 return -EFAULT;
1710 }
1711 return err;
1712}
1713
1714#ifdef __ARCH_WANT_SYS_WAITPID
1715
1716
1717
1718
1719
1720SYSCALL_DEFINE3(waitpid, pid_t, pid, int __user *, stat_addr, int, options)
1721{
1722 return kernel_wait4(pid, stat_addr, options, NULL);
1723}
1724
1725#endif
1726
1727#ifdef CONFIG_COMPAT
1728COMPAT_SYSCALL_DEFINE4(wait4,
1729 compat_pid_t, pid,
1730 compat_uint_t __user *, stat_addr,
1731 int, options,
1732 struct compat_rusage __user *, ru)
1733{
1734 struct rusage r;
1735 long err = kernel_wait4(pid, stat_addr, options, ru ? &r : NULL);
1736 if (err > 0) {
1737 if (ru && put_compat_rusage(&r, ru))
1738 return -EFAULT;
1739 }
1740 return err;
1741}
1742
1743COMPAT_SYSCALL_DEFINE5(waitid,
1744 int, which, compat_pid_t, pid,
1745 struct compat_siginfo __user *, infop, int, options,
1746 struct compat_rusage __user *, uru)
1747{
1748 struct rusage ru;
1749 struct waitid_info info = {.status = 0};
1750 long err = kernel_waitid(which, pid, &info, options, uru ? &ru : NULL);
1751 int signo = 0;
1752 if (err > 0) {
1753 signo = SIGCHLD;
1754 err = 0;
1755 if (uru) {
1756
1757 if (COMPAT_USE_64BIT_TIME)
1758 err = copy_to_user(uru, &ru, sizeof(ru));
1759 else
1760 err = put_compat_rusage(&ru, uru);
1761 if (err)
1762 return -EFAULT;
1763 }
1764 }
1765
1766 if (!infop)
1767 return err;
1768
1769 if (!user_write_access_begin(infop, sizeof(*infop)))
1770 return -EFAULT;
1771
1772 unsafe_put_user(signo, &infop->si_signo, Efault);
1773 unsafe_put_user(0, &infop->si_errno, Efault);
1774 unsafe_put_user(info.cause, &infop->si_code, Efault);
1775 unsafe_put_user(info.pid, &infop->si_pid, Efault);
1776 unsafe_put_user(info.uid, &infop->si_uid, Efault);
1777 unsafe_put_user(info.status, &infop->si_status, Efault);
1778 user_write_access_end();
1779 return err;
1780Efault:
1781 user_write_access_end();
1782 return -EFAULT;
1783}
1784#endif
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795bool thread_group_exited(struct pid *pid)
1796{
1797 struct task_struct *task;
1798 bool exited;
1799
1800 rcu_read_lock();
1801 task = pid_task(pid, PIDTYPE_PID);
1802 exited = !task ||
1803 (READ_ONCE(task->exit_state) && thread_group_empty(task));
1804 rcu_read_unlock();
1805
1806 return exited;
1807}
1808EXPORT_SYMBOL(thread_group_exited);
1809
1810__weak void abort(void)
1811{
1812 BUG();
1813
1814
1815 panic("Oops failed to kill thread");
1816}
1817EXPORT_SYMBOL(abort);
1818