1 // SPDX-License-Identifier: GPL-2.0-only
5 * Copyright (C) 1991, 1992 Linus Torvalds
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> /* for audit_free() */
50 #include <linux/resource.h>
51 #include <linux/task_io_accounting_ops.h>
52 #include <linux/blkdev.h>
53 #include <linux/task_work.h>
54 #include <linux/fs_struct.h>
55 #include <linux/init_task.h>
56 #include <linux/perf_event.h>
57 #include <trace/events/sched.h>
58 #include <linux/hw_breakpoint.h>
59 #include <linux/oom.h>
60 #include <linux/writeback.h>
61 #include <linux/shm.h>
62 #include <linux/kcov.h>
63 #include <linux/kmsan.h>
64 #include <linux/random.h>
65 #include <linux/rcuwait.h>
66 #include <linux/compat.h>
67 #include <linux/io_uring.h>
68 #include <linux/kprobes.h>
69 #include <linux/rethook.h>
70 #include <linux/sysfs.h>
71 #include <linux/user_events.h>
73 #include <linux/uaccess.h>
74 #include <asm/unistd.h>
75 #include <asm/mmu_context.h>
78 * The default value should be high enough to not crash a system that randomly
79 * crashes its kernel from time to time, but low enough to at least not permit
80 * overflowing 32-bit refcounts or the ldsem writer count.
82 static unsigned int oops_limit
= 10000;
85 static struct ctl_table kern_exit_table
[] = {
87 .procname
= "oops_limit",
89 .maxlen
= sizeof(oops_limit
),
91 .proc_handler
= proc_douintvec
,
96 static __init
int kernel_exit_sysctls_init(void)
98 register_sysctl_init("kernel", kern_exit_table
);
101 late_initcall(kernel_exit_sysctls_init
);
104 static atomic_t oops_count
= ATOMIC_INIT(0);
107 static ssize_t
oops_count_show(struct kobject
*kobj
, struct kobj_attribute
*attr
,
110 return sysfs_emit(page
, "%d\n", atomic_read(&oops_count
));
113 static struct kobj_attribute oops_count_attr
= __ATTR_RO(oops_count
);
115 static __init
int kernel_exit_sysfs_init(void)
117 sysfs_add_file_to_group(kernel_kobj
, &oops_count_attr
.attr
, NULL
);
120 late_initcall(kernel_exit_sysfs_init
);
123 static void __unhash_process(struct task_struct
*p
, bool group_dead
)
126 detach_pid(p
, PIDTYPE_PID
);
128 detach_pid(p
, PIDTYPE_TGID
);
129 detach_pid(p
, PIDTYPE_PGID
);
130 detach_pid(p
, PIDTYPE_SID
);
132 list_del_rcu(&p
->tasks
);
133 list_del_init(&p
->sibling
);
134 __this_cpu_dec(process_counts
);
136 list_del_rcu(&p
->thread_group
);
137 list_del_rcu(&p
->thread_node
);
141 * This function expects the tasklist_lock write-locked.
143 static void __exit_signal(struct task_struct
*tsk
)
145 struct signal_struct
*sig
= tsk
->signal
;
146 bool group_dead
= thread_group_leader(tsk
);
147 struct sighand_struct
*sighand
;
148 struct tty_struct
*tty
;
151 sighand
= rcu_dereference_check(tsk
->sighand
,
152 lockdep_tasklist_lock_is_held());
153 spin_lock(&sighand
->siglock
);
155 #ifdef CONFIG_POSIX_TIMERS
156 posix_cpu_timers_exit(tsk
);
158 posix_cpu_timers_exit_group(tsk
);
166 * If there is any task waiting for the group exit
169 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
170 wake_up_process(sig
->group_exec_task
);
172 if (tsk
== sig
->curr_target
)
173 sig
->curr_target
= next_thread(tsk
);
176 add_device_randomness((const void*) &tsk
->se
.sum_exec_runtime
,
177 sizeof(unsigned long long));
180 * Accumulate here the counters for all threads as they die. We could
181 * skip the group leader because it is the last user of signal_struct,
182 * but we want to avoid the race with thread_group_cputime() which can
183 * see the empty ->thread_head list.
185 task_cputime(tsk
, &utime
, &stime
);
186 write_seqlock(&sig
->stats_lock
);
189 sig
->gtime
+= task_gtime(tsk
);
190 sig
->min_flt
+= tsk
->min_flt
;
191 sig
->maj_flt
+= tsk
->maj_flt
;
192 sig
->nvcsw
+= tsk
->nvcsw
;
193 sig
->nivcsw
+= tsk
->nivcsw
;
194 sig
->inblock
+= task_io_get_inblock(tsk
);
195 sig
->oublock
+= task_io_get_oublock(tsk
);
196 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
197 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
199 __unhash_process(tsk
, group_dead
);
200 write_sequnlock(&sig
->stats_lock
);
203 * Do this under ->siglock, we can race with another thread
204 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
206 flush_sigqueue(&tsk
->pending
);
208 spin_unlock(&sighand
->siglock
);
210 __cleanup_sighand(sighand
);
211 clear_tsk_thread_flag(tsk
, TIF_SIGPENDING
);
213 flush_sigqueue(&sig
->shared_pending
);
218 static void delayed_put_task_struct(struct rcu_head
*rhp
)
220 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
222 kprobe_flush_task(tsk
);
223 rethook_flush_task(tsk
);
224 perf_event_delayed_put(tsk
);
225 trace_sched_process_free(tsk
);
226 put_task_struct(tsk
);
229 void put_task_struct_rcu_user(struct task_struct
*task
)
231 if (refcount_dec_and_test(&task
->rcu_users
))
232 call_rcu(&task
->rcu
, delayed_put_task_struct
);
235 void __weak
release_thread(struct task_struct
*dead_task
)
239 void release_task(struct task_struct
*p
)
241 struct task_struct
*leader
;
242 struct pid
*thread_pid
;
245 /* don't need to get the RCU readlock here - the process is dead and
246 * can't be modifying its own credentials. But shut RCU-lockdep up */
248 dec_rlimit_ucounts(task_ucounts(p
), UCOUNT_RLIMIT_NPROC
, 1);
253 write_lock_irq(&tasklist_lock
);
254 ptrace_release_task(p
);
255 thread_pid
= get_pid(p
->thread_pid
);
259 * If we are the last non-leader member of the thread
260 * group, and the leader is zombie, then notify the
261 * group leader's parent process. (if it wants notification.)
264 leader
= p
->group_leader
;
265 if (leader
!= p
&& thread_group_empty(leader
)
266 && leader
->exit_state
== EXIT_ZOMBIE
) {
268 * If we were the last child thread and the leader has
269 * exited already, and the leader's parent ignores SIGCHLD,
270 * then we are the one who should release the leader.
272 zap_leader
= do_notify_parent(leader
, leader
->exit_signal
);
274 leader
->exit_state
= EXIT_DEAD
;
277 write_unlock_irq(&tasklist_lock
);
278 seccomp_filter_release(p
);
279 proc_flush_pid(thread_pid
);
282 put_task_struct_rcu_user(p
);
285 if (unlikely(zap_leader
))
289 int rcuwait_wake_up(struct rcuwait
*w
)
292 struct task_struct
*task
;
297 * Order condition vs @task, such that everything prior to the load
298 * of @task is visible. This is the condition as to why the user called
299 * rcuwait_wake() in the first place. Pairs with set_current_state()
300 * barrier (A) in rcuwait_wait_event().
303 * [S] tsk = current [S] cond = true
309 task
= rcu_dereference(w
->task
);
311 ret
= wake_up_process(task
);
316 EXPORT_SYMBOL_GPL(rcuwait_wake_up
);
319 * Determine if a process group is "orphaned", according to the POSIX
320 * definition in 2.2.2.52. Orphaned process groups are not to be affected
321 * by terminal-generated stop signals. Newly orphaned process groups are
322 * to receive a SIGHUP and a SIGCONT.
324 * "I ask you, have you ever known what it is to be an orphan?"
326 static int will_become_orphaned_pgrp(struct pid
*pgrp
,
327 struct task_struct
*ignored_task
)
329 struct task_struct
*p
;
331 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
332 if ((p
== ignored_task
) ||
333 (p
->exit_state
&& thread_group_empty(p
)) ||
334 is_global_init(p
->real_parent
))
337 if (task_pgrp(p
->real_parent
) != pgrp
&&
338 task_session(p
->real_parent
) == task_session(p
))
340 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
345 int is_current_pgrp_orphaned(void)
349 read_lock(&tasklist_lock
);
350 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
351 read_unlock(&tasklist_lock
);
356 static bool has_stopped_jobs(struct pid
*pgrp
)
358 struct task_struct
*p
;
360 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
361 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
363 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
369 * Check to see if any process groups have become orphaned as
370 * a result of our exiting, and if they have any stopped jobs,
371 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
374 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
376 struct pid
*pgrp
= task_pgrp(tsk
);
377 struct task_struct
*ignored_task
= tsk
;
380 /* exit: our father is in a different pgrp than
381 * we are and we were the only connection outside.
383 parent
= tsk
->real_parent
;
385 /* reparent: our child is in a different pgrp than
386 * we are, and it was the only connection outside.
390 if (task_pgrp(parent
) != pgrp
&&
391 task_session(parent
) == task_session(tsk
) &&
392 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
393 has_stopped_jobs(pgrp
)) {
394 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
395 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
399 static void coredump_task_exit(struct task_struct
*tsk
)
401 struct core_state
*core_state
;
404 * Serialize with any possible pending coredump.
405 * We must hold siglock around checking core_state
406 * and setting PF_POSTCOREDUMP. The core-inducing thread
407 * will increment ->nr_threads for each thread in the
408 * group without PF_POSTCOREDUMP set.
410 spin_lock_irq(&tsk
->sighand
->siglock
);
411 tsk
->flags
|= PF_POSTCOREDUMP
;
412 core_state
= tsk
->signal
->core_state
;
413 spin_unlock_irq(&tsk
->sighand
->siglock
);
415 /* The vhost_worker does not particpate in coredumps */
417 ((tsk
->flags
& (PF_IO_WORKER
| PF_USER_WORKER
)) != PF_USER_WORKER
)) {
418 struct core_thread self
;
421 if (self
.task
->flags
& PF_SIGNALED
)
422 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
426 * Implies mb(), the result of xchg() must be visible
427 * to core_state->dumper.
429 if (atomic_dec_and_test(&core_state
->nr_threads
))
430 complete(&core_state
->startup
);
433 set_current_state(TASK_UNINTERRUPTIBLE
|TASK_FREEZABLE
);
434 if (!self
.task
) /* see coredump_finish() */
438 __set_current_state(TASK_RUNNING
);
444 * A task is exiting. If it owned this mm, find a new owner for the mm.
446 void mm_update_next_owner(struct mm_struct
*mm
)
448 struct task_struct
*c
, *g
, *p
= current
;
452 * If the exiting or execing task is not the owner, it's
453 * someone else's problem.
458 * The current owner is exiting/execing and there are no other
459 * candidates. Do not leave the mm pointing to a possibly
460 * freed task structure.
462 if (atomic_read(&mm
->mm_users
) <= 1) {
463 WRITE_ONCE(mm
->owner
, NULL
);
467 read_lock(&tasklist_lock
);
469 * Search in the children
471 list_for_each_entry(c
, &p
->children
, sibling
) {
473 goto assign_new_owner
;
477 * Search in the siblings
479 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
481 goto assign_new_owner
;
485 * Search through everything else, we should not get here often.
487 for_each_process(g
) {
488 if (g
->flags
& PF_KTHREAD
)
490 for_each_thread(g
, c
) {
492 goto assign_new_owner
;
497 read_unlock(&tasklist_lock
);
499 * We found no owner yet mm_users > 1: this implies that we are
500 * most likely racing with swapoff (try_to_unuse()) or /proc or
501 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
503 WRITE_ONCE(mm
->owner
, NULL
);
510 * The task_lock protects c->mm from changing.
511 * We always want mm->owner->mm == mm
515 * Delay read_unlock() till we have the task_lock()
516 * to ensure that c does not slip away underneath us
518 read_unlock(&tasklist_lock
);
524 WRITE_ONCE(mm
->owner
, c
);
525 lru_gen_migrate_mm(mm
);
529 #endif /* CONFIG_MEMCG */
532 * Turn us into a lazy TLB process if we
535 static void exit_mm(void)
537 struct mm_struct
*mm
= current
->mm
;
539 exit_mm_release(current
, mm
);
545 BUG_ON(mm
!= current
->active_mm
);
546 /* more a memory barrier than a real lock */
549 * When a thread stops operating on an address space, the loop
550 * in membarrier_private_expedited() may not observe that
551 * tsk->mm, and the loop in membarrier_global_expedited() may
552 * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
553 * rq->membarrier_state, so those would not issue an IPI.
554 * Membarrier requires a memory barrier after accessing
555 * user-space memory, before clearing tsk->mm or the
556 * rq->membarrier_state.
558 smp_mb__after_spinlock();
561 membarrier_update_current_mm(NULL
);
562 enter_lazy_tlb(mm
, current
);
564 task_unlock(current
);
565 mmap_read_unlock(mm
);
566 mm_update_next_owner(mm
);
568 if (test_thread_flag(TIF_MEMDIE
))
572 static struct task_struct
*find_alive_thread(struct task_struct
*p
)
574 struct task_struct
*t
;
576 for_each_thread(p
, t
) {
577 if (!(t
->flags
& PF_EXITING
))
583 static struct task_struct
*find_child_reaper(struct task_struct
*father
,
584 struct list_head
*dead
)
585 __releases(&tasklist_lock
)
586 __acquires(&tasklist_lock
)
588 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
589 struct task_struct
*reaper
= pid_ns
->child_reaper
;
590 struct task_struct
*p
, *n
;
592 if (likely(reaper
!= father
))
595 reaper
= find_alive_thread(father
);
597 pid_ns
->child_reaper
= reaper
;
601 write_unlock_irq(&tasklist_lock
);
603 list_for_each_entry_safe(p
, n
, dead
, ptrace_entry
) {
604 list_del_init(&p
->ptrace_entry
);
608 zap_pid_ns_processes(pid_ns
);
609 write_lock_irq(&tasklist_lock
);
615 * When we die, we re-parent all our children, and try to:
616 * 1. give them to another thread in our thread group, if such a member exists
617 * 2. give it to the first ancestor process which prctl'd itself as a
618 * child_subreaper for its children (like a service manager)
619 * 3. give it to the init process (PID 1) in our pid namespace
621 static struct task_struct
*find_new_reaper(struct task_struct
*father
,
622 struct task_struct
*child_reaper
)
624 struct task_struct
*thread
, *reaper
;
626 thread
= find_alive_thread(father
);
630 if (father
->signal
->has_child_subreaper
) {
631 unsigned int ns_level
= task_pid(father
)->level
;
633 * Find the first ->is_child_subreaper ancestor in our pid_ns.
634 * We can't check reaper != child_reaper to ensure we do not
635 * cross the namespaces, the exiting parent could be injected
636 * by setns() + fork().
637 * We check pid->level, this is slightly more efficient than
638 * task_active_pid_ns(reaper) != task_active_pid_ns(father).
640 for (reaper
= father
->real_parent
;
641 task_pid(reaper
)->level
== ns_level
;
642 reaper
= reaper
->real_parent
) {
643 if (reaper
== &init_task
)
645 if (!reaper
->signal
->is_child_subreaper
)
647 thread
= find_alive_thread(reaper
);
657 * Any that need to be release_task'd are put on the @dead list.
659 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
660 struct list_head
*dead
)
662 if (unlikely(p
->exit_state
== EXIT_DEAD
))
665 /* We don't want people slaying init. */
666 p
->exit_signal
= SIGCHLD
;
668 /* If it has exited notify the new parent about this child's death. */
670 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
671 if (do_notify_parent(p
, p
->exit_signal
)) {
672 p
->exit_state
= EXIT_DEAD
;
673 list_add(&p
->ptrace_entry
, dead
);
677 kill_orphaned_pgrp(p
, father
);
681 * This does two things:
683 * A. Make init inherit all the child processes
684 * B. Check to see if any process groups have become orphaned
685 * as a result of our exiting, and if they have any stopped
686 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
688 static void forget_original_parent(struct task_struct
*father
,
689 struct list_head
*dead
)
691 struct task_struct
*p
, *t
, *reaper
;
693 if (unlikely(!list_empty(&father
->ptraced
)))
694 exit_ptrace(father
, dead
);
696 /* Can drop and reacquire tasklist_lock */
697 reaper
= find_child_reaper(father
, dead
);
698 if (list_empty(&father
->children
))
701 reaper
= find_new_reaper(father
, reaper
);
702 list_for_each_entry(p
, &father
->children
, sibling
) {
703 for_each_thread(p
, t
) {
704 RCU_INIT_POINTER(t
->real_parent
, reaper
);
705 BUG_ON((!t
->ptrace
) != (rcu_access_pointer(t
->parent
) == father
));
706 if (likely(!t
->ptrace
))
707 t
->parent
= t
->real_parent
;
708 if (t
->pdeath_signal
)
709 group_send_sig_info(t
->pdeath_signal
,
714 * If this is a threaded reparent there is no need to
715 * notify anyone anything has happened.
717 if (!same_thread_group(reaper
, father
))
718 reparent_leader(father
, p
, dead
);
720 list_splice_tail_init(&father
->children
, &reaper
->children
);
724 * Send signals to all our closest relatives so that they know
725 * to properly mourn us..
727 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
730 struct task_struct
*p
, *n
;
733 write_lock_irq(&tasklist_lock
);
734 forget_original_parent(tsk
, &dead
);
737 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
739 tsk
->exit_state
= EXIT_ZOMBIE
;
740 if (unlikely(tsk
->ptrace
)) {
741 int sig
= thread_group_leader(tsk
) &&
742 thread_group_empty(tsk
) &&
743 !ptrace_reparented(tsk
) ?
744 tsk
->exit_signal
: SIGCHLD
;
745 autoreap
= do_notify_parent(tsk
, sig
);
746 } else if (thread_group_leader(tsk
)) {
747 autoreap
= thread_group_empty(tsk
) &&
748 do_notify_parent(tsk
, tsk
->exit_signal
);
754 tsk
->exit_state
= EXIT_DEAD
;
755 list_add(&tsk
->ptrace_entry
, &dead
);
758 /* mt-exec, de_thread() is waiting for group leader */
759 if (unlikely(tsk
->signal
->notify_count
< 0))
760 wake_up_process(tsk
->signal
->group_exec_task
);
761 write_unlock_irq(&tasklist_lock
);
763 list_for_each_entry_safe(p
, n
, &dead
, ptrace_entry
) {
764 list_del_init(&p
->ptrace_entry
);
769 #ifdef CONFIG_DEBUG_STACK_USAGE
770 static void check_stack_usage(void)
772 static DEFINE_SPINLOCK(low_water_lock
);
773 static int lowest_to_date
= THREAD_SIZE
;
776 free
= stack_not_used(current
);
778 if (free
>= lowest_to_date
)
781 spin_lock(&low_water_lock
);
782 if (free
< lowest_to_date
) {
783 pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
784 current
->comm
, task_pid_nr(current
), free
);
785 lowest_to_date
= free
;
787 spin_unlock(&low_water_lock
);
790 static inline void check_stack_usage(void) {}
793 static void synchronize_group_exit(struct task_struct
*tsk
, long code
)
795 struct sighand_struct
*sighand
= tsk
->sighand
;
796 struct signal_struct
*signal
= tsk
->signal
;
798 spin_lock_irq(&sighand
->siglock
);
799 signal
->quick_threads
--;
800 if ((signal
->quick_threads
== 0) &&
801 !(signal
->flags
& SIGNAL_GROUP_EXIT
)) {
802 signal
->flags
= SIGNAL_GROUP_EXIT
;
803 signal
->group_exit_code
= code
;
804 signal
->group_stop_count
= 0;
806 spin_unlock_irq(&sighand
->siglock
);
809 void __noreturn
do_exit(long code
)
811 struct task_struct
*tsk
= current
;
814 WARN_ON(irqs_disabled());
816 synchronize_group_exit(tsk
, code
);
821 kmsan_task_exit(tsk
);
823 coredump_task_exit(tsk
);
824 ptrace_event(PTRACE_EVENT_EXIT
, code
);
825 user_events_exit(tsk
);
827 validate_creds_for_do_exit(tsk
);
829 io_uring_files_cancel();
830 exit_signals(tsk
); /* sets PF_EXITING */
832 /* sync mm's RSS info before statistics gathering */
834 sync_mm_rss(tsk
->mm
);
835 acct_update_integrals(tsk
);
836 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
839 * If the last thread of global init has exited, panic
840 * immediately to get a useable coredump.
842 if (unlikely(is_global_init(tsk
)))
843 panic("Attempted to kill init! exitcode=0x%08x\n",
844 tsk
->signal
->group_exit_code
?: (int)code
);
846 #ifdef CONFIG_POSIX_TIMERS
847 hrtimer_cancel(&tsk
->signal
->real_timer
);
851 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
853 acct_collect(code
, group_dead
);
858 tsk
->exit_code
= code
;
859 taskstats_exit(tsk
, group_dead
);
865 trace_sched_process_exit(tsk
);
872 disassociate_ctty(1);
873 exit_task_namespaces(tsk
);
878 * Flush inherited counters to the parent - before the parent
879 * gets woken up by child-exit notifications.
881 * because of cgroup mode, must be called before cgroup_exit()
883 perf_event_exit_task(tsk
);
885 sched_autogroup_exit_task(tsk
);
889 * FIXME: do that only when needed, using sched_exit tracepoint
891 flush_ptrace_hw_breakpoint(tsk
);
893 exit_tasks_rcu_start();
894 exit_notify(tsk
, group_dead
);
895 proc_exit_connector(tsk
);
896 mpol_put_task_policy(tsk
);
898 if (unlikely(current
->pi_state_cache
))
899 kfree(current
->pi_state_cache
);
902 * Make sure we are holding no locks:
904 debug_check_no_locks_held();
907 exit_io_context(tsk
);
909 if (tsk
->splice_pipe
)
910 free_pipe_info(tsk
->splice_pipe
);
912 if (tsk
->task_frag
.page
)
913 put_page(tsk
->task_frag
.page
);
915 validate_creds_for_do_exit(tsk
);
916 exit_task_stack_account(tsk
);
921 __this_cpu_add(dirty_throttle_leaks
, tsk
->nr_dirtied
);
923 exit_tasks_rcu_finish();
925 lockdep_free_task(tsk
);
929 void __noreturn
make_task_dead(int signr
)
932 * Take the task off the cpu after something catastrophic has
935 * We can get here from a kernel oops, sometimes with preemption off.
936 * Start by checking for critical errors.
937 * Then fix up important state like USER_DS and preemption.
938 * Then do everything else.
940 struct task_struct
*tsk
= current
;
943 if (unlikely(in_interrupt()))
944 panic("Aiee, killing interrupt handler!");
945 if (unlikely(!tsk
->pid
))
946 panic("Attempted to kill the idle task!");
948 if (unlikely(irqs_disabled())) {
949 pr_info("note: %s[%d] exited with irqs disabled\n",
950 current
->comm
, task_pid_nr(current
));
953 if (unlikely(in_atomic())) {
954 pr_info("note: %s[%d] exited with preempt_count %d\n",
955 current
->comm
, task_pid_nr(current
),
957 preempt_count_set(PREEMPT_ENABLED
);
961 * Every time the system oopses, if the oops happens while a reference
962 * to an object was held, the reference leaks.
963 * If the oops doesn't also leak memory, repeated oopsing can cause
964 * reference counters to wrap around (if they're not using refcount_t).
965 * This means that repeated oopsing can make unexploitable-looking bugs
966 * exploitable through repeated oopsing.
967 * To make sure this can't happen, place an upper bound on how often the
968 * kernel may oops without panic().
970 limit
= READ_ONCE(oops_limit
);
971 if (atomic_inc_return(&oops_count
) >= limit
&& limit
)
972 panic("Oopsed too often (kernel.oops_limit is %d)", limit
);
975 * We're taking recursive faults here in make_task_dead. Safest is to just
976 * leave this task alone and wait for reboot.
978 if (unlikely(tsk
->flags
& PF_EXITING
)) {
979 pr_alert("Fixing recursive fault but reboot is needed!\n");
980 futex_exit_recursive(tsk
);
981 tsk
->exit_state
= EXIT_DEAD
;
982 refcount_inc(&tsk
->rcu_users
);
989 SYSCALL_DEFINE1(exit
, int, error_code
)
991 do_exit((error_code
&0xff)<<8);
995 * Take down every thread in the group. This is called by fatal signals
996 * as well as by sys_exit_group (below).
999 do_group_exit(int exit_code
)
1001 struct signal_struct
*sig
= current
->signal
;
1003 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
1004 exit_code
= sig
->group_exit_code
;
1005 else if (sig
->group_exec_task
)
1008 struct sighand_struct
*const sighand
= current
->sighand
;
1010 spin_lock_irq(&sighand
->siglock
);
1011 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
1012 /* Another thread got here before we took the lock. */
1013 exit_code
= sig
->group_exit_code
;
1014 else if (sig
->group_exec_task
)
1017 sig
->group_exit_code
= exit_code
;
1018 sig
->flags
= SIGNAL_GROUP_EXIT
;
1019 zap_other_threads(current
);
1021 spin_unlock_irq(&sighand
->siglock
);
1029 * this kills every thread in the thread group. Note that any externally
1030 * wait4()-ing process will get the correct exit code - even if this
1031 * thread is not the thread group leader.
1033 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1035 do_group_exit((error_code
& 0xff) << 8);
1040 struct waitid_info
{
1048 enum pid_type wo_type
;
1052 struct waitid_info
*wo_info
;
1054 struct rusage
*wo_rusage
;
1056 wait_queue_entry_t child_wait
;
1060 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1062 return wo
->wo_type
== PIDTYPE_MAX
||
1063 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1067 eligible_child(struct wait_opts
*wo
, bool ptrace
, struct task_struct
*p
)
1069 if (!eligible_pid(wo
, p
))
1073 * Wait for all children (clone and not) if __WALL is set or
1074 * if it is traced by us.
1076 if (ptrace
|| (wo
->wo_flags
& __WALL
))
1080 * Otherwise, wait for clone children *only* if __WCLONE is set;
1081 * otherwise, wait for non-clone children *only*.
1083 * Note: a "clone" child here is one that reports to its parent
1084 * using a signal other than SIGCHLD, or a non-leader thread which
1085 * we can only see if it is traced by us.
1087 if ((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1094 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1095 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1096 * the lock and this task is uninteresting. If we return nonzero, we have
1097 * released the lock and the system call should return.
1099 static int wait_task_zombie(struct wait_opts
*wo
, struct task_struct
*p
)
1102 pid_t pid
= task_pid_vnr(p
);
1103 uid_t uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1104 struct waitid_info
*infop
;
1106 if (!likely(wo
->wo_flags
& WEXITED
))
1109 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1110 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1111 ? p
->signal
->group_exit_code
: p
->exit_code
;
1113 read_unlock(&tasklist_lock
);
1114 sched_annotate_sleep();
1116 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1121 * Move the task's state to DEAD/TRACE, only one thread can do this.
1123 state
= (ptrace_reparented(p
) && thread_group_leader(p
)) ?
1124 EXIT_TRACE
: EXIT_DEAD
;
1125 if (cmpxchg(&p
->exit_state
, EXIT_ZOMBIE
, state
) != EXIT_ZOMBIE
)
1128 * We own this thread, nobody else can reap it.
1130 read_unlock(&tasklist_lock
);
1131 sched_annotate_sleep();
1134 * Check thread_group_leader() to exclude the traced sub-threads.
1136 if (state
== EXIT_DEAD
&& thread_group_leader(p
)) {
1137 struct signal_struct
*sig
= p
->signal
;
1138 struct signal_struct
*psig
= current
->signal
;
1139 unsigned long maxrss
;
1140 u64 tgutime
, tgstime
;
1143 * The resource counters for the group leader are in its
1144 * own task_struct. Those for dead threads in the group
1145 * are in its signal_struct, as are those for the child
1146 * processes it has previously reaped. All these
1147 * accumulate in the parent's signal_struct c* fields.
1149 * We don't bother to take a lock here to protect these
1150 * p->signal fields because the whole thread group is dead
1151 * and nobody can change them.
1153 * psig->stats_lock also protects us from our sub-threads
1154 * which can reap other children at the same time. Until
1155 * we change k_getrusage()-like users to rely on this lock
1156 * we have to take ->siglock as well.
1158 * We use thread_group_cputime_adjusted() to get times for
1159 * the thread group, which consolidates times for all threads
1160 * in the group including the group leader.
1162 thread_group_cputime_adjusted(p
, &tgutime
, &tgstime
);
1163 spin_lock_irq(¤t
->sighand
->siglock
);
1164 write_seqlock(&psig
->stats_lock
);
1165 psig
->cutime
+= tgutime
+ sig
->cutime
;
1166 psig
->cstime
+= tgstime
+ sig
->cstime
;
1167 psig
->cgtime
+= task_gtime(p
) + sig
->gtime
+ sig
->cgtime
;
1169 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1171 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1173 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1175 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1177 task_io_get_inblock(p
) +
1178 sig
->inblock
+ sig
->cinblock
;
1180 task_io_get_oublock(p
) +
1181 sig
->oublock
+ sig
->coublock
;
1182 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1183 if (psig
->cmaxrss
< maxrss
)
1184 psig
->cmaxrss
= maxrss
;
1185 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1186 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1187 write_sequnlock(&psig
->stats_lock
);
1188 spin_unlock_irq(¤t
->sighand
->siglock
);
1192 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1193 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1194 ? p
->signal
->group_exit_code
: p
->exit_code
;
1195 wo
->wo_stat
= status
;
1197 if (state
== EXIT_TRACE
) {
1198 write_lock_irq(&tasklist_lock
);
1199 /* We dropped tasklist, ptracer could die and untrace */
1202 /* If parent wants a zombie, don't release it now */
1203 state
= EXIT_ZOMBIE
;
1204 if (do_notify_parent(p
, p
->exit_signal
))
1206 p
->exit_state
= state
;
1207 write_unlock_irq(&tasklist_lock
);
1209 if (state
== EXIT_DEAD
)
1213 infop
= wo
->wo_info
;
1215 if ((status
& 0x7f) == 0) {
1216 infop
->cause
= CLD_EXITED
;
1217 infop
->status
= status
>> 8;
1219 infop
->cause
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1220 infop
->status
= status
& 0x7f;
1229 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1232 if (task_is_traced(p
) && !(p
->jobctl
& JOBCTL_LISTENING
))
1233 return &p
->exit_code
;
1235 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1236 return &p
->signal
->group_exit_code
;
1242 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1244 * @ptrace: is the wait for ptrace
1245 * @p: task to wait for
1247 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1250 * read_lock(&tasklist_lock), which is released if return value is
1251 * non-zero. Also, grabs and releases @p->sighand->siglock.
1254 * 0 if wait condition didn't exist and search for other wait conditions
1255 * should continue. Non-zero return, -errno on failure and @p's pid on
1256 * success, implies that tasklist_lock is released and wait condition
1257 * search should terminate.
1259 static int wait_task_stopped(struct wait_opts
*wo
,
1260 int ptrace
, struct task_struct
*p
)
1262 struct waitid_info
*infop
;
1263 int exit_code
, *p_code
, why
;
1264 uid_t uid
= 0; /* unneeded, required by compiler */
1268 * Traditionally we see ptrace'd stopped tasks regardless of options.
1270 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1273 if (!task_stopped_code(p
, ptrace
))
1277 spin_lock_irq(&p
->sighand
->siglock
);
1279 p_code
= task_stopped_code(p
, ptrace
);
1280 if (unlikely(!p_code
))
1283 exit_code
= *p_code
;
1287 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1290 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1292 spin_unlock_irq(&p
->sighand
->siglock
);
1297 * Now we are pretty sure this task is interesting.
1298 * Make sure it doesn't get reaped out from under us while we
1299 * give up the lock and then examine it below. We don't want to
1300 * keep holding onto the tasklist_lock while we call getrusage and
1301 * possibly take page faults for user memory.
1304 pid
= task_pid_vnr(p
);
1305 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1306 read_unlock(&tasklist_lock
);
1307 sched_annotate_sleep();
1309 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1312 if (likely(!(wo
->wo_flags
& WNOWAIT
)))
1313 wo
->wo_stat
= (exit_code
<< 8) | 0x7f;
1315 infop
= wo
->wo_info
;
1318 infop
->status
= exit_code
;
1326 * Handle do_wait work for one task in a live, non-stopped state.
1327 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1328 * the lock and this task is uninteresting. If we return nonzero, we have
1329 * released the lock and the system call should return.
1331 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1333 struct waitid_info
*infop
;
1337 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1340 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1343 spin_lock_irq(&p
->sighand
->siglock
);
1344 /* Re-check with the lock held. */
1345 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1346 spin_unlock_irq(&p
->sighand
->siglock
);
1349 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1350 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1351 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1352 spin_unlock_irq(&p
->sighand
->siglock
);
1354 pid
= task_pid_vnr(p
);
1356 read_unlock(&tasklist_lock
);
1357 sched_annotate_sleep();
1359 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1362 infop
= wo
->wo_info
;
1364 wo
->wo_stat
= 0xffff;
1366 infop
->cause
= CLD_CONTINUED
;
1369 infop
->status
= SIGCONT
;
1375 * Consider @p for a wait by @parent.
1377 * -ECHILD should be in ->notask_error before the first call.
1378 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1379 * Returns zero if the search for a child should continue;
1380 * then ->notask_error is 0 if @p is an eligible child,
1383 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1384 struct task_struct
*p
)
1387 * We can race with wait_task_zombie() from another thread.
1388 * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
1389 * can't confuse the checks below.
1391 int exit_state
= READ_ONCE(p
->exit_state
);
1394 if (unlikely(exit_state
== EXIT_DEAD
))
1397 ret
= eligible_child(wo
, ptrace
, p
);
1401 if (unlikely(exit_state
== EXIT_TRACE
)) {
1403 * ptrace == 0 means we are the natural parent. In this case
1404 * we should clear notask_error, debugger will notify us.
1406 if (likely(!ptrace
))
1407 wo
->notask_error
= 0;
1411 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1413 * If it is traced by its real parent's group, just pretend
1414 * the caller is ptrace_do_wait() and reap this child if it
1417 * This also hides group stop state from real parent; otherwise
1418 * a single stop can be reported twice as group and ptrace stop.
1419 * If a ptracer wants to distinguish these two events for its
1420 * own children it should create a separate process which takes
1421 * the role of real parent.
1423 if (!ptrace_reparented(p
))
1428 if (exit_state
== EXIT_ZOMBIE
) {
1429 /* we don't reap group leaders with subthreads */
1430 if (!delay_group_leader(p
)) {
1432 * A zombie ptracee is only visible to its ptracer.
1433 * Notification and reaping will be cascaded to the
1434 * real parent when the ptracer detaches.
1436 if (unlikely(ptrace
) || likely(!p
->ptrace
))
1437 return wait_task_zombie(wo
, p
);
1441 * Allow access to stopped/continued state via zombie by
1442 * falling through. Clearing of notask_error is complex.
1446 * If WEXITED is set, notask_error should naturally be
1447 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1448 * so, if there are live subthreads, there are events to
1449 * wait for. If all subthreads are dead, it's still safe
1450 * to clear - this function will be called again in finite
1451 * amount time once all the subthreads are released and
1452 * will then return without clearing.
1456 * Stopped state is per-task and thus can't change once the
1457 * target task dies. Only continued and exited can happen.
1458 * Clear notask_error if WCONTINUED | WEXITED.
1460 if (likely(!ptrace
) || (wo
->wo_flags
& (WCONTINUED
| WEXITED
)))
1461 wo
->notask_error
= 0;
1464 * @p is alive and it's gonna stop, continue or exit, so
1465 * there always is something to wait for.
1467 wo
->notask_error
= 0;
1471 * Wait for stopped. Depending on @ptrace, different stopped state
1472 * is used and the two don't interact with each other.
1474 ret
= wait_task_stopped(wo
, ptrace
, p
);
1479 * Wait for continued. There's only one continued state and the
1480 * ptracer can consume it which can confuse the real parent. Don't
1481 * use WCONTINUED from ptracer. You don't need or want it.
1483 return wait_task_continued(wo
, p
);
1487 * Do the work of do_wait() for one thread in the group, @tsk.
1489 * -ECHILD should be in ->notask_error before the first call.
1490 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1491 * Returns zero if the search for a child should continue; then
1492 * ->notask_error is 0 if there were any eligible children,
1495 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1497 struct task_struct
*p
;
1499 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1500 int ret
= wait_consider_task(wo
, 0, p
);
1509 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1511 struct task_struct
*p
;
1513 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1514 int ret
= wait_consider_task(wo
, 1, p
);
1523 static int child_wait_callback(wait_queue_entry_t
*wait
, unsigned mode
,
1524 int sync
, void *key
)
1526 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1528 struct task_struct
*p
= key
;
1530 if (!eligible_pid(wo
, p
))
1533 if ((wo
->wo_flags
& __WNOTHREAD
) && wait
->private != p
->parent
)
1536 return default_wake_function(wait
, mode
, sync
, key
);
1539 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1541 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1542 TASK_INTERRUPTIBLE
, p
);
1545 static bool is_effectively_child(struct wait_opts
*wo
, bool ptrace
,
1546 struct task_struct
*target
)
1548 struct task_struct
*parent
=
1549 !ptrace
? target
->real_parent
: target
->parent
;
1551 return current
== parent
|| (!(wo
->wo_flags
& __WNOTHREAD
) &&
1552 same_thread_group(current
, parent
));
1556 * Optimization for waiting on PIDTYPE_PID. No need to iterate through child
1557 * and tracee lists to find the target task.
1559 static int do_wait_pid(struct wait_opts
*wo
)
1562 struct task_struct
*target
;
1566 target
= pid_task(wo
->wo_pid
, PIDTYPE_TGID
);
1567 if (target
&& is_effectively_child(wo
, ptrace
, target
)) {
1568 retval
= wait_consider_task(wo
, ptrace
, target
);
1574 target
= pid_task(wo
->wo_pid
, PIDTYPE_PID
);
1575 if (target
&& target
->ptrace
&&
1576 is_effectively_child(wo
, ptrace
, target
)) {
1577 retval
= wait_consider_task(wo
, ptrace
, target
);
1585 static long do_wait(struct wait_opts
*wo
)
1589 trace_sched_process_wait(wo
->wo_pid
);
1591 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1592 wo
->child_wait
.private = current
;
1593 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1596 * If there is nothing that can match our criteria, just get out.
1597 * We will clear ->notask_error to zero if we see any child that
1598 * might later match our criteria, even if we are not able to reap
1601 wo
->notask_error
= -ECHILD
;
1602 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1603 (!wo
->wo_pid
|| !pid_has_task(wo
->wo_pid
, wo
->wo_type
)))
1606 set_current_state(TASK_INTERRUPTIBLE
);
1607 read_lock(&tasklist_lock
);
1609 if (wo
->wo_type
== PIDTYPE_PID
) {
1610 retval
= do_wait_pid(wo
);
1614 struct task_struct
*tsk
= current
;
1617 retval
= do_wait_thread(wo
, tsk
);
1621 retval
= ptrace_do_wait(wo
, tsk
);
1625 if (wo
->wo_flags
& __WNOTHREAD
)
1627 } while_each_thread(current
, tsk
);
1629 read_unlock(&tasklist_lock
);
1632 retval
= wo
->notask_error
;
1633 if (!retval
&& !(wo
->wo_flags
& WNOHANG
)) {
1634 retval
= -ERESTARTSYS
;
1635 if (!signal_pending(current
)) {
1641 __set_current_state(TASK_RUNNING
);
1642 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1646 static long kernel_waitid(int which
, pid_t upid
, struct waitid_info
*infop
,
1647 int options
, struct rusage
*ru
)
1649 struct wait_opts wo
;
1650 struct pid
*pid
= NULL
;
1653 unsigned int f_flags
= 0;
1655 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
|
1656 __WNOTHREAD
|__WCLONE
|__WALL
))
1658 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1670 pid
= find_get_pid(upid
);
1673 type
= PIDTYPE_PGID
;
1678 pid
= find_get_pid(upid
);
1680 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1687 pid
= pidfd_get_pid(upid
, &f_flags
);
1689 return PTR_ERR(pid
);
1698 wo
.wo_flags
= options
;
1701 if (f_flags
& O_NONBLOCK
)
1702 wo
.wo_flags
|= WNOHANG
;
1705 if (!ret
&& !(options
& WNOHANG
) && (f_flags
& O_NONBLOCK
))
1712 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1713 infop
, int, options
, struct rusage __user
*, ru
)
1716 struct waitid_info info
= {.status
= 0};
1717 long err
= kernel_waitid(which
, upid
, &info
, options
, ru
? &r
: NULL
);
1723 if (ru
&& copy_to_user(ru
, &r
, sizeof(struct rusage
)))
1729 if (!user_write_access_begin(infop
, sizeof(*infop
)))
1732 unsafe_put_user(signo
, &infop
->si_signo
, Efault
);
1733 unsafe_put_user(0, &infop
->si_errno
, Efault
);
1734 unsafe_put_user(info
.cause
, &infop
->si_code
, Efault
);
1735 unsafe_put_user(info
.pid
, &infop
->si_pid
, Efault
);
1736 unsafe_put_user(info
.uid
, &infop
->si_uid
, Efault
);
1737 unsafe_put_user(info
.status
, &infop
->si_status
, Efault
);
1738 user_write_access_end();
1741 user_write_access_end();
1745 long kernel_wait4(pid_t upid
, int __user
*stat_addr
, int options
,
1748 struct wait_opts wo
;
1749 struct pid
*pid
= NULL
;
1753 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1754 __WNOTHREAD
|__WCLONE
|__WALL
))
1757 /* -INT_MIN is not defined */
1758 if (upid
== INT_MIN
)
1763 else if (upid
< 0) {
1764 type
= PIDTYPE_PGID
;
1765 pid
= find_get_pid(-upid
);
1766 } else if (upid
== 0) {
1767 type
= PIDTYPE_PGID
;
1768 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1769 } else /* upid > 0 */ {
1771 pid
= find_get_pid(upid
);
1776 wo
.wo_flags
= options
| WEXITED
;
1782 if (ret
> 0 && stat_addr
&& put_user(wo
.wo_stat
, stat_addr
))
1788 int kernel_wait(pid_t pid
, int *stat
)
1790 struct wait_opts wo
= {
1791 .wo_type
= PIDTYPE_PID
,
1792 .wo_pid
= find_get_pid(pid
),
1793 .wo_flags
= WEXITED
,
1798 if (ret
> 0 && wo
.wo_stat
)
1804 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1805 int, options
, struct rusage __user
*, ru
)
1808 long err
= kernel_wait4(upid
, stat_addr
, options
, ru
? &r
: NULL
);
1811 if (ru
&& copy_to_user(ru
, &r
, sizeof(struct rusage
)))
1817 #ifdef __ARCH_WANT_SYS_WAITPID
1820 * sys_waitpid() remains for compatibility. waitpid() should be
1821 * implemented by calling sys_wait4() from libc.a.
1823 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1825 return kernel_wait4(pid
, stat_addr
, options
, NULL
);
1830 #ifdef CONFIG_COMPAT
1831 COMPAT_SYSCALL_DEFINE4(wait4
,
1833 compat_uint_t __user
*, stat_addr
,
1835 struct compat_rusage __user
*, ru
)
1838 long err
= kernel_wait4(pid
, stat_addr
, options
, ru
? &r
: NULL
);
1840 if (ru
&& put_compat_rusage(&r
, ru
))
1846 COMPAT_SYSCALL_DEFINE5(waitid
,
1847 int, which
, compat_pid_t
, pid
,
1848 struct compat_siginfo __user
*, infop
, int, options
,
1849 struct compat_rusage __user
*, uru
)
1852 struct waitid_info info
= {.status
= 0};
1853 long err
= kernel_waitid(which
, pid
, &info
, options
, uru
? &ru
: NULL
);
1859 /* kernel_waitid() overwrites everything in ru */
1860 if (COMPAT_USE_64BIT_TIME
)
1861 err
= copy_to_user(uru
, &ru
, sizeof(ru
));
1863 err
= put_compat_rusage(&ru
, uru
);
1872 if (!user_write_access_begin(infop
, sizeof(*infop
)))
1875 unsafe_put_user(signo
, &infop
->si_signo
, Efault
);
1876 unsafe_put_user(0, &infop
->si_errno
, Efault
);
1877 unsafe_put_user(info
.cause
, &infop
->si_code
, Efault
);
1878 unsafe_put_user(info
.pid
, &infop
->si_pid
, Efault
);
1879 unsafe_put_user(info
.uid
, &infop
->si_uid
, Efault
);
1880 unsafe_put_user(info
.status
, &infop
->si_status
, Efault
);
1881 user_write_access_end();
1884 user_write_access_end();
1890 * thread_group_exited - check that a thread group has exited
1891 * @pid: tgid of thread group to be checked.
1893 * Test if the thread group represented by tgid has exited (all
1894 * threads are zombies, dead or completely gone).
1896 * Return: true if the thread group has exited. false otherwise.
1898 bool thread_group_exited(struct pid
*pid
)
1900 struct task_struct
*task
;
1904 task
= pid_task(pid
, PIDTYPE_PID
);
1906 (READ_ONCE(task
->exit_state
) && thread_group_empty(task
));
1911 EXPORT_SYMBOL(thread_group_exited
);
1914 * This needs to be __function_aligned as GCC implicitly makes any
1915 * implementation of abort() cold and drops alignment specified by
1916 * -falign-functions=N.
1918 * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c11
1920 __weak __function_aligned
void abort(void)
1924 /* if that doesn't kill us, halt */
1925 panic("Oops failed to kill thread");
1927 EXPORT_SYMBOL(abort
);