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>
72 #include <linux/uaccess.h>
74 #include <uapi/linux/wait.h>
76 #include <asm/unistd.h>
77 #include <asm/mmu_context.h>
82 * The default value should be high enough to not crash a system that randomly
83 * crashes its kernel from time to time, but low enough to at least not permit
84 * overflowing 32-bit refcounts or the ldsem writer count.
86 static unsigned int oops_limit
= 10000;
89 static struct ctl_table kern_exit_table
[] = {
91 .procname
= "oops_limit",
93 .maxlen
= sizeof(oops_limit
),
95 .proc_handler
= proc_douintvec
,
100 static __init
int kernel_exit_sysctls_init(void)
102 register_sysctl_init("kernel", kern_exit_table
);
105 late_initcall(kernel_exit_sysctls_init
);
108 static atomic_t oops_count
= ATOMIC_INIT(0);
111 static ssize_t
oops_count_show(struct kobject
*kobj
, struct kobj_attribute
*attr
,
114 return sysfs_emit(page
, "%d\n", atomic_read(&oops_count
));
117 static struct kobj_attribute oops_count_attr
= __ATTR_RO(oops_count
);
119 static __init
int kernel_exit_sysfs_init(void)
121 sysfs_add_file_to_group(kernel_kobj
, &oops_count_attr
.attr
, NULL
);
124 late_initcall(kernel_exit_sysfs_init
);
127 static void __unhash_process(struct task_struct
*p
, bool group_dead
)
130 detach_pid(p
, PIDTYPE_PID
);
132 detach_pid(p
, PIDTYPE_TGID
);
133 detach_pid(p
, PIDTYPE_PGID
);
134 detach_pid(p
, PIDTYPE_SID
);
136 list_del_rcu(&p
->tasks
);
137 list_del_init(&p
->sibling
);
138 __this_cpu_dec(process_counts
);
140 list_del_rcu(&p
->thread_node
);
144 * This function expects the tasklist_lock write-locked.
146 static void __exit_signal(struct task_struct
*tsk
)
148 struct signal_struct
*sig
= tsk
->signal
;
149 bool group_dead
= thread_group_leader(tsk
);
150 struct sighand_struct
*sighand
;
151 struct tty_struct
*tty
;
154 sighand
= rcu_dereference_check(tsk
->sighand
,
155 lockdep_tasklist_lock_is_held());
156 spin_lock(&sighand
->siglock
);
158 #ifdef CONFIG_POSIX_TIMERS
159 posix_cpu_timers_exit(tsk
);
161 posix_cpu_timers_exit_group(tsk
);
169 * If there is any task waiting for the group exit
172 if (sig
->notify_count
> 0 && !--sig
->notify_count
)
173 wake_up_process(sig
->group_exec_task
);
175 if (tsk
== sig
->curr_target
)
176 sig
->curr_target
= next_thread(tsk
);
179 add_device_randomness((const void*) &tsk
->se
.sum_exec_runtime
,
180 sizeof(unsigned long long));
183 * Accumulate here the counters for all threads as they die. We could
184 * skip the group leader because it is the last user of signal_struct,
185 * but we want to avoid the race with thread_group_cputime() which can
186 * see the empty ->thread_head list.
188 task_cputime(tsk
, &utime
, &stime
);
189 write_seqlock(&sig
->stats_lock
);
192 sig
->gtime
+= task_gtime(tsk
);
193 sig
->min_flt
+= tsk
->min_flt
;
194 sig
->maj_flt
+= tsk
->maj_flt
;
195 sig
->nvcsw
+= tsk
->nvcsw
;
196 sig
->nivcsw
+= tsk
->nivcsw
;
197 sig
->inblock
+= task_io_get_inblock(tsk
);
198 sig
->oublock
+= task_io_get_oublock(tsk
);
199 task_io_accounting_add(&sig
->ioac
, &tsk
->ioac
);
200 sig
->sum_sched_runtime
+= tsk
->se
.sum_exec_runtime
;
202 __unhash_process(tsk
, group_dead
);
203 write_sequnlock(&sig
->stats_lock
);
206 * Do this under ->siglock, we can race with another thread
207 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
209 flush_sigqueue(&tsk
->pending
);
211 spin_unlock(&sighand
->siglock
);
213 __cleanup_sighand(sighand
);
214 clear_tsk_thread_flag(tsk
, TIF_SIGPENDING
);
216 flush_sigqueue(&sig
->shared_pending
);
221 static void delayed_put_task_struct(struct rcu_head
*rhp
)
223 struct task_struct
*tsk
= container_of(rhp
, struct task_struct
, rcu
);
225 kprobe_flush_task(tsk
);
226 rethook_flush_task(tsk
);
227 perf_event_delayed_put(tsk
);
228 trace_sched_process_free(tsk
);
229 put_task_struct(tsk
);
232 void put_task_struct_rcu_user(struct task_struct
*task
)
234 if (refcount_dec_and_test(&task
->rcu_users
))
235 call_rcu(&task
->rcu
, delayed_put_task_struct
);
238 void __weak
release_thread(struct task_struct
*dead_task
)
242 void release_task(struct task_struct
*p
)
244 struct task_struct
*leader
;
245 struct pid
*thread_pid
;
248 /* don't need to get the RCU readlock here - the process is dead and
249 * can't be modifying its own credentials. But shut RCU-lockdep up */
251 dec_rlimit_ucounts(task_ucounts(p
), UCOUNT_RLIMIT_NPROC
, 1);
256 write_lock_irq(&tasklist_lock
);
257 ptrace_release_task(p
);
258 thread_pid
= get_pid(p
->thread_pid
);
262 * If we are the last non-leader member of the thread
263 * group, and the leader is zombie, then notify the
264 * group leader's parent process. (if it wants notification.)
267 leader
= p
->group_leader
;
268 if (leader
!= p
&& thread_group_empty(leader
)
269 && leader
->exit_state
== EXIT_ZOMBIE
) {
271 * If we were the last child thread and the leader has
272 * exited already, and the leader's parent ignores SIGCHLD,
273 * then we are the one who should release the leader.
275 zap_leader
= do_notify_parent(leader
, leader
->exit_signal
);
277 leader
->exit_state
= EXIT_DEAD
;
280 write_unlock_irq(&tasklist_lock
);
281 seccomp_filter_release(p
);
282 proc_flush_pid(thread_pid
);
285 put_task_struct_rcu_user(p
);
288 if (unlikely(zap_leader
))
292 int rcuwait_wake_up(struct rcuwait
*w
)
295 struct task_struct
*task
;
300 * Order condition vs @task, such that everything prior to the load
301 * of @task is visible. This is the condition as to why the user called
302 * rcuwait_wake() in the first place. Pairs with set_current_state()
303 * barrier (A) in rcuwait_wait_event().
306 * [S] tsk = current [S] cond = true
312 task
= rcu_dereference(w
->task
);
314 ret
= wake_up_process(task
);
319 EXPORT_SYMBOL_GPL(rcuwait_wake_up
);
322 * Determine if a process group is "orphaned", according to the POSIX
323 * definition in 2.2.2.52. Orphaned process groups are not to be affected
324 * by terminal-generated stop signals. Newly orphaned process groups are
325 * to receive a SIGHUP and a SIGCONT.
327 * "I ask you, have you ever known what it is to be an orphan?"
329 static int will_become_orphaned_pgrp(struct pid
*pgrp
,
330 struct task_struct
*ignored_task
)
332 struct task_struct
*p
;
334 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
335 if ((p
== ignored_task
) ||
336 (p
->exit_state
&& thread_group_empty(p
)) ||
337 is_global_init(p
->real_parent
))
340 if (task_pgrp(p
->real_parent
) != pgrp
&&
341 task_session(p
->real_parent
) == task_session(p
))
343 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
348 int is_current_pgrp_orphaned(void)
352 read_lock(&tasklist_lock
);
353 retval
= will_become_orphaned_pgrp(task_pgrp(current
), NULL
);
354 read_unlock(&tasklist_lock
);
359 static bool has_stopped_jobs(struct pid
*pgrp
)
361 struct task_struct
*p
;
363 do_each_pid_task(pgrp
, PIDTYPE_PGID
, p
) {
364 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
366 } while_each_pid_task(pgrp
, PIDTYPE_PGID
, p
);
372 * Check to see if any process groups have become orphaned as
373 * a result of our exiting, and if they have any stopped jobs,
374 * send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
377 kill_orphaned_pgrp(struct task_struct
*tsk
, struct task_struct
*parent
)
379 struct pid
*pgrp
= task_pgrp(tsk
);
380 struct task_struct
*ignored_task
= tsk
;
383 /* exit: our father is in a different pgrp than
384 * we are and we were the only connection outside.
386 parent
= tsk
->real_parent
;
388 /* reparent: our child is in a different pgrp than
389 * we are, and it was the only connection outside.
393 if (task_pgrp(parent
) != pgrp
&&
394 task_session(parent
) == task_session(tsk
) &&
395 will_become_orphaned_pgrp(pgrp
, ignored_task
) &&
396 has_stopped_jobs(pgrp
)) {
397 __kill_pgrp_info(SIGHUP
, SEND_SIG_PRIV
, pgrp
);
398 __kill_pgrp_info(SIGCONT
, SEND_SIG_PRIV
, pgrp
);
402 static void coredump_task_exit(struct task_struct
*tsk
)
404 struct core_state
*core_state
;
407 * Serialize with any possible pending coredump.
408 * We must hold siglock around checking core_state
409 * and setting PF_POSTCOREDUMP. The core-inducing thread
410 * will increment ->nr_threads for each thread in the
411 * group without PF_POSTCOREDUMP set.
413 spin_lock_irq(&tsk
->sighand
->siglock
);
414 tsk
->flags
|= PF_POSTCOREDUMP
;
415 core_state
= tsk
->signal
->core_state
;
416 spin_unlock_irq(&tsk
->sighand
->siglock
);
418 /* The vhost_worker does not particpate in coredumps */
420 ((tsk
->flags
& (PF_IO_WORKER
| PF_USER_WORKER
)) != PF_USER_WORKER
)) {
421 struct core_thread self
;
424 if (self
.task
->flags
& PF_SIGNALED
)
425 self
.next
= xchg(&core_state
->dumper
.next
, &self
);
429 * Implies mb(), the result of xchg() must be visible
430 * to core_state->dumper.
432 if (atomic_dec_and_test(&core_state
->nr_threads
))
433 complete(&core_state
->startup
);
436 set_current_state(TASK_UNINTERRUPTIBLE
|TASK_FREEZABLE
);
437 if (!self
.task
) /* see coredump_finish() */
441 __set_current_state(TASK_RUNNING
);
447 * A task is exiting. If it owned this mm, find a new owner for the mm.
449 void mm_update_next_owner(struct mm_struct
*mm
)
451 struct task_struct
*c
, *g
, *p
= current
;
455 * If the exiting or execing task is not the owner, it's
456 * someone else's problem.
461 * The current owner is exiting/execing and there are no other
462 * candidates. Do not leave the mm pointing to a possibly
463 * freed task structure.
465 if (atomic_read(&mm
->mm_users
) <= 1) {
466 WRITE_ONCE(mm
->owner
, NULL
);
470 read_lock(&tasklist_lock
);
472 * Search in the children
474 list_for_each_entry(c
, &p
->children
, sibling
) {
476 goto assign_new_owner
;
480 * Search in the siblings
482 list_for_each_entry(c
, &p
->real_parent
->children
, sibling
) {
484 goto assign_new_owner
;
488 * Search through everything else, we should not get here often.
490 for_each_process(g
) {
491 if (g
->flags
& PF_KTHREAD
)
493 for_each_thread(g
, c
) {
495 goto assign_new_owner
;
500 read_unlock(&tasklist_lock
);
502 * We found no owner yet mm_users > 1: this implies that we are
503 * most likely racing with swapoff (try_to_unuse()) or /proc or
504 * ptrace or page migration (get_task_mm()). Mark owner as NULL.
506 WRITE_ONCE(mm
->owner
, NULL
);
513 * The task_lock protects c->mm from changing.
514 * We always want mm->owner->mm == mm
518 * Delay read_unlock() till we have the task_lock()
519 * to ensure that c does not slip away underneath us
521 read_unlock(&tasklist_lock
);
527 WRITE_ONCE(mm
->owner
, c
);
528 lru_gen_migrate_mm(mm
);
532 #endif /* CONFIG_MEMCG */
535 * Turn us into a lazy TLB process if we
538 static void exit_mm(void)
540 struct mm_struct
*mm
= current
->mm
;
542 exit_mm_release(current
, mm
);
547 BUG_ON(mm
!= current
->active_mm
);
548 /* more a memory barrier than a real lock */
551 * When a thread stops operating on an address space, the loop
552 * in membarrier_private_expedited() may not observe that
553 * tsk->mm, and the loop in membarrier_global_expedited() may
554 * not observe a MEMBARRIER_STATE_GLOBAL_EXPEDITED
555 * rq->membarrier_state, so those would not issue an IPI.
556 * Membarrier requires a memory barrier after accessing
557 * user-space memory, before clearing tsk->mm or the
558 * rq->membarrier_state.
560 smp_mb__after_spinlock();
563 membarrier_update_current_mm(NULL
);
564 enter_lazy_tlb(mm
, current
);
566 task_unlock(current
);
567 mmap_read_unlock(mm
);
568 mm_update_next_owner(mm
);
570 if (test_thread_flag(TIF_MEMDIE
))
574 static struct task_struct
*find_alive_thread(struct task_struct
*p
)
576 struct task_struct
*t
;
578 for_each_thread(p
, t
) {
579 if (!(t
->flags
& PF_EXITING
))
585 static struct task_struct
*find_child_reaper(struct task_struct
*father
,
586 struct list_head
*dead
)
587 __releases(&tasklist_lock
)
588 __acquires(&tasklist_lock
)
590 struct pid_namespace
*pid_ns
= task_active_pid_ns(father
);
591 struct task_struct
*reaper
= pid_ns
->child_reaper
;
592 struct task_struct
*p
, *n
;
594 if (likely(reaper
!= father
))
597 reaper
= find_alive_thread(father
);
599 pid_ns
->child_reaper
= reaper
;
603 write_unlock_irq(&tasklist_lock
);
605 list_for_each_entry_safe(p
, n
, dead
, ptrace_entry
) {
606 list_del_init(&p
->ptrace_entry
);
610 zap_pid_ns_processes(pid_ns
);
611 write_lock_irq(&tasklist_lock
);
617 * When we die, we re-parent all our children, and try to:
618 * 1. give them to another thread in our thread group, if such a member exists
619 * 2. give it to the first ancestor process which prctl'd itself as a
620 * child_subreaper for its children (like a service manager)
621 * 3. give it to the init process (PID 1) in our pid namespace
623 static struct task_struct
*find_new_reaper(struct task_struct
*father
,
624 struct task_struct
*child_reaper
)
626 struct task_struct
*thread
, *reaper
;
628 thread
= find_alive_thread(father
);
632 if (father
->signal
->has_child_subreaper
) {
633 unsigned int ns_level
= task_pid(father
)->level
;
635 * Find the first ->is_child_subreaper ancestor in our pid_ns.
636 * We can't check reaper != child_reaper to ensure we do not
637 * cross the namespaces, the exiting parent could be injected
638 * by setns() + fork().
639 * We check pid->level, this is slightly more efficient than
640 * task_active_pid_ns(reaper) != task_active_pid_ns(father).
642 for (reaper
= father
->real_parent
;
643 task_pid(reaper
)->level
== ns_level
;
644 reaper
= reaper
->real_parent
) {
645 if (reaper
== &init_task
)
647 if (!reaper
->signal
->is_child_subreaper
)
649 thread
= find_alive_thread(reaper
);
659 * Any that need to be release_task'd are put on the @dead list.
661 static void reparent_leader(struct task_struct
*father
, struct task_struct
*p
,
662 struct list_head
*dead
)
664 if (unlikely(p
->exit_state
== EXIT_DEAD
))
667 /* We don't want people slaying init. */
668 p
->exit_signal
= SIGCHLD
;
670 /* If it has exited notify the new parent about this child's death. */
672 p
->exit_state
== EXIT_ZOMBIE
&& thread_group_empty(p
)) {
673 if (do_notify_parent(p
, p
->exit_signal
)) {
674 p
->exit_state
= EXIT_DEAD
;
675 list_add(&p
->ptrace_entry
, dead
);
679 kill_orphaned_pgrp(p
, father
);
683 * This does two things:
685 * A. Make init inherit all the child processes
686 * B. Check to see if any process groups have become orphaned
687 * as a result of our exiting, and if they have any stopped
688 * jobs, send them a SIGHUP and then a SIGCONT. (POSIX 3.2.2.2)
690 static void forget_original_parent(struct task_struct
*father
,
691 struct list_head
*dead
)
693 struct task_struct
*p
, *t
, *reaper
;
695 if (unlikely(!list_empty(&father
->ptraced
)))
696 exit_ptrace(father
, dead
);
698 /* Can drop and reacquire tasklist_lock */
699 reaper
= find_child_reaper(father
, dead
);
700 if (list_empty(&father
->children
))
703 reaper
= find_new_reaper(father
, reaper
);
704 list_for_each_entry(p
, &father
->children
, sibling
) {
705 for_each_thread(p
, t
) {
706 RCU_INIT_POINTER(t
->real_parent
, reaper
);
707 BUG_ON((!t
->ptrace
) != (rcu_access_pointer(t
->parent
) == father
));
708 if (likely(!t
->ptrace
))
709 t
->parent
= t
->real_parent
;
710 if (t
->pdeath_signal
)
711 group_send_sig_info(t
->pdeath_signal
,
716 * If this is a threaded reparent there is no need to
717 * notify anyone anything has happened.
719 if (!same_thread_group(reaper
, father
))
720 reparent_leader(father
, p
, dead
);
722 list_splice_tail_init(&father
->children
, &reaper
->children
);
726 * Send signals to all our closest relatives so that they know
727 * to properly mourn us..
729 static void exit_notify(struct task_struct
*tsk
, int group_dead
)
732 struct task_struct
*p
, *n
;
735 write_lock_irq(&tasklist_lock
);
736 forget_original_parent(tsk
, &dead
);
739 kill_orphaned_pgrp(tsk
->group_leader
, NULL
);
741 tsk
->exit_state
= EXIT_ZOMBIE
;
743 * sub-thread or delay_group_leader(), wake up the
744 * PIDFD_THREAD waiters.
746 if (!thread_group_empty(tsk
))
747 do_notify_pidfd(tsk
);
749 if (unlikely(tsk
->ptrace
)) {
750 int sig
= thread_group_leader(tsk
) &&
751 thread_group_empty(tsk
) &&
752 !ptrace_reparented(tsk
) ?
753 tsk
->exit_signal
: SIGCHLD
;
754 autoreap
= do_notify_parent(tsk
, sig
);
755 } else if (thread_group_leader(tsk
)) {
756 autoreap
= thread_group_empty(tsk
) &&
757 do_notify_parent(tsk
, tsk
->exit_signal
);
763 tsk
->exit_state
= EXIT_DEAD
;
764 list_add(&tsk
->ptrace_entry
, &dead
);
767 /* mt-exec, de_thread() is waiting for group leader */
768 if (unlikely(tsk
->signal
->notify_count
< 0))
769 wake_up_process(tsk
->signal
->group_exec_task
);
770 write_unlock_irq(&tasklist_lock
);
772 list_for_each_entry_safe(p
, n
, &dead
, ptrace_entry
) {
773 list_del_init(&p
->ptrace_entry
);
778 #ifdef CONFIG_DEBUG_STACK_USAGE
779 static void check_stack_usage(void)
781 static DEFINE_SPINLOCK(low_water_lock
);
782 static int lowest_to_date
= THREAD_SIZE
;
785 free
= stack_not_used(current
);
787 if (free
>= lowest_to_date
)
790 spin_lock(&low_water_lock
);
791 if (free
< lowest_to_date
) {
792 pr_info("%s (%d) used greatest stack depth: %lu bytes left\n",
793 current
->comm
, task_pid_nr(current
), free
);
794 lowest_to_date
= free
;
796 spin_unlock(&low_water_lock
);
799 static inline void check_stack_usage(void) {}
802 static void synchronize_group_exit(struct task_struct
*tsk
, long code
)
804 struct sighand_struct
*sighand
= tsk
->sighand
;
805 struct signal_struct
*signal
= tsk
->signal
;
807 spin_lock_irq(&sighand
->siglock
);
808 signal
->quick_threads
--;
809 if ((signal
->quick_threads
== 0) &&
810 !(signal
->flags
& SIGNAL_GROUP_EXIT
)) {
811 signal
->flags
= SIGNAL_GROUP_EXIT
;
812 signal
->group_exit_code
= code
;
813 signal
->group_stop_count
= 0;
815 spin_unlock_irq(&sighand
->siglock
);
818 void __noreturn
do_exit(long code
)
820 struct task_struct
*tsk
= current
;
823 WARN_ON(irqs_disabled());
825 synchronize_group_exit(tsk
, code
);
830 kmsan_task_exit(tsk
);
832 coredump_task_exit(tsk
);
833 ptrace_event(PTRACE_EVENT_EXIT
, code
);
834 user_events_exit(tsk
);
836 io_uring_files_cancel();
837 exit_signals(tsk
); /* sets PF_EXITING */
839 acct_update_integrals(tsk
);
840 group_dead
= atomic_dec_and_test(&tsk
->signal
->live
);
843 * If the last thread of global init has exited, panic
844 * immediately to get a useable coredump.
846 if (unlikely(is_global_init(tsk
)))
847 panic("Attempted to kill init! exitcode=0x%08x\n",
848 tsk
->signal
->group_exit_code
?: (int)code
);
850 #ifdef CONFIG_POSIX_TIMERS
851 hrtimer_cancel(&tsk
->signal
->real_timer
);
855 setmax_mm_hiwater_rss(&tsk
->signal
->maxrss
, tsk
->mm
);
857 acct_collect(code
, group_dead
);
862 tsk
->exit_code
= code
;
863 taskstats_exit(tsk
, group_dead
);
869 trace_sched_process_exit(tsk
);
876 disassociate_ctty(1);
877 exit_task_namespaces(tsk
);
882 * Flush inherited counters to the parent - before the parent
883 * gets woken up by child-exit notifications.
885 * because of cgroup mode, must be called before cgroup_exit()
887 perf_event_exit_task(tsk
);
889 sched_autogroup_exit_task(tsk
);
893 * FIXME: do that only when needed, using sched_exit tracepoint
895 flush_ptrace_hw_breakpoint(tsk
);
897 exit_tasks_rcu_start();
898 exit_notify(tsk
, group_dead
);
899 proc_exit_connector(tsk
);
900 mpol_put_task_policy(tsk
);
902 if (unlikely(current
->pi_state_cache
))
903 kfree(current
->pi_state_cache
);
906 * Make sure we are holding no locks:
908 debug_check_no_locks_held();
911 exit_io_context(tsk
);
913 if (tsk
->splice_pipe
)
914 free_pipe_info(tsk
->splice_pipe
);
916 if (tsk
->task_frag
.page
)
917 put_page(tsk
->task_frag
.page
);
919 exit_task_stack_account(tsk
);
924 __this_cpu_add(dirty_throttle_leaks
, tsk
->nr_dirtied
);
926 exit_tasks_rcu_finish();
928 lockdep_free_task(tsk
);
932 void __noreturn
make_task_dead(int signr
)
935 * Take the task off the cpu after something catastrophic has
938 * We can get here from a kernel oops, sometimes with preemption off.
939 * Start by checking for critical errors.
940 * Then fix up important state like USER_DS and preemption.
941 * Then do everything else.
943 struct task_struct
*tsk
= current
;
946 if (unlikely(in_interrupt()))
947 panic("Aiee, killing interrupt handler!");
948 if (unlikely(!tsk
->pid
))
949 panic("Attempted to kill the idle task!");
951 if (unlikely(irqs_disabled())) {
952 pr_info("note: %s[%d] exited with irqs disabled\n",
953 current
->comm
, task_pid_nr(current
));
956 if (unlikely(in_atomic())) {
957 pr_info("note: %s[%d] exited with preempt_count %d\n",
958 current
->comm
, task_pid_nr(current
),
960 preempt_count_set(PREEMPT_ENABLED
);
964 * Every time the system oopses, if the oops happens while a reference
965 * to an object was held, the reference leaks.
966 * If the oops doesn't also leak memory, repeated oopsing can cause
967 * reference counters to wrap around (if they're not using refcount_t).
968 * This means that repeated oopsing can make unexploitable-looking bugs
969 * exploitable through repeated oopsing.
970 * To make sure this can't happen, place an upper bound on how often the
971 * kernel may oops without panic().
973 limit
= READ_ONCE(oops_limit
);
974 if (atomic_inc_return(&oops_count
) >= limit
&& limit
)
975 panic("Oopsed too often (kernel.oops_limit is %d)", limit
);
978 * We're taking recursive faults here in make_task_dead. Safest is to just
979 * leave this task alone and wait for reboot.
981 if (unlikely(tsk
->flags
& PF_EXITING
)) {
982 pr_alert("Fixing recursive fault but reboot is needed!\n");
983 futex_exit_recursive(tsk
);
984 tsk
->exit_state
= EXIT_DEAD
;
985 refcount_inc(&tsk
->rcu_users
);
992 SYSCALL_DEFINE1(exit
, int, error_code
)
994 do_exit((error_code
&0xff)<<8);
998 * Take down every thread in the group. This is called by fatal signals
999 * as well as by sys_exit_group (below).
1002 do_group_exit(int exit_code
)
1004 struct signal_struct
*sig
= current
->signal
;
1006 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
1007 exit_code
= sig
->group_exit_code
;
1008 else if (sig
->group_exec_task
)
1011 struct sighand_struct
*const sighand
= current
->sighand
;
1013 spin_lock_irq(&sighand
->siglock
);
1014 if (sig
->flags
& SIGNAL_GROUP_EXIT
)
1015 /* Another thread got here before we took the lock. */
1016 exit_code
= sig
->group_exit_code
;
1017 else if (sig
->group_exec_task
)
1020 sig
->group_exit_code
= exit_code
;
1021 sig
->flags
= SIGNAL_GROUP_EXIT
;
1022 zap_other_threads(current
);
1024 spin_unlock_irq(&sighand
->siglock
);
1032 * this kills every thread in the thread group. Note that any externally
1033 * wait4()-ing process will get the correct exit code - even if this
1034 * thread is not the thread group leader.
1036 SYSCALL_DEFINE1(exit_group
, int, error_code
)
1038 do_group_exit((error_code
& 0xff) << 8);
1043 static int eligible_pid(struct wait_opts
*wo
, struct task_struct
*p
)
1045 return wo
->wo_type
== PIDTYPE_MAX
||
1046 task_pid_type(p
, wo
->wo_type
) == wo
->wo_pid
;
1050 eligible_child(struct wait_opts
*wo
, bool ptrace
, struct task_struct
*p
)
1052 if (!eligible_pid(wo
, p
))
1056 * Wait for all children (clone and not) if __WALL is set or
1057 * if it is traced by us.
1059 if (ptrace
|| (wo
->wo_flags
& __WALL
))
1063 * Otherwise, wait for clone children *only* if __WCLONE is set;
1064 * otherwise, wait for non-clone children *only*.
1066 * Note: a "clone" child here is one that reports to its parent
1067 * using a signal other than SIGCHLD, or a non-leader thread which
1068 * we can only see if it is traced by us.
1070 if ((p
->exit_signal
!= SIGCHLD
) ^ !!(wo
->wo_flags
& __WCLONE
))
1077 * Handle sys_wait4 work for one task in state EXIT_ZOMBIE. We hold
1078 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1079 * the lock and this task is uninteresting. If we return nonzero, we have
1080 * released the lock and the system call should return.
1082 static int wait_task_zombie(struct wait_opts
*wo
, struct task_struct
*p
)
1085 pid_t pid
= task_pid_vnr(p
);
1086 uid_t uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1087 struct waitid_info
*infop
;
1089 if (!likely(wo
->wo_flags
& WEXITED
))
1092 if (unlikely(wo
->wo_flags
& WNOWAIT
)) {
1093 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1094 ? p
->signal
->group_exit_code
: p
->exit_code
;
1096 read_unlock(&tasklist_lock
);
1097 sched_annotate_sleep();
1099 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1104 * Move the task's state to DEAD/TRACE, only one thread can do this.
1106 state
= (ptrace_reparented(p
) && thread_group_leader(p
)) ?
1107 EXIT_TRACE
: EXIT_DEAD
;
1108 if (cmpxchg(&p
->exit_state
, EXIT_ZOMBIE
, state
) != EXIT_ZOMBIE
)
1111 * We own this thread, nobody else can reap it.
1113 read_unlock(&tasklist_lock
);
1114 sched_annotate_sleep();
1117 * Check thread_group_leader() to exclude the traced sub-threads.
1119 if (state
== EXIT_DEAD
&& thread_group_leader(p
)) {
1120 struct signal_struct
*sig
= p
->signal
;
1121 struct signal_struct
*psig
= current
->signal
;
1122 unsigned long maxrss
;
1123 u64 tgutime
, tgstime
;
1126 * The resource counters for the group leader are in its
1127 * own task_struct. Those for dead threads in the group
1128 * are in its signal_struct, as are those for the child
1129 * processes it has previously reaped. All these
1130 * accumulate in the parent's signal_struct c* fields.
1132 * We don't bother to take a lock here to protect these
1133 * p->signal fields because the whole thread group is dead
1134 * and nobody can change them.
1136 * psig->stats_lock also protects us from our sub-threads
1137 * which can reap other children at the same time.
1139 * We use thread_group_cputime_adjusted() to get times for
1140 * the thread group, which consolidates times for all threads
1141 * in the group including the group leader.
1143 thread_group_cputime_adjusted(p
, &tgutime
, &tgstime
);
1144 write_seqlock_irq(&psig
->stats_lock
);
1145 psig
->cutime
+= tgutime
+ sig
->cutime
;
1146 psig
->cstime
+= tgstime
+ sig
->cstime
;
1147 psig
->cgtime
+= task_gtime(p
) + sig
->gtime
+ sig
->cgtime
;
1149 p
->min_flt
+ sig
->min_flt
+ sig
->cmin_flt
;
1151 p
->maj_flt
+ sig
->maj_flt
+ sig
->cmaj_flt
;
1153 p
->nvcsw
+ sig
->nvcsw
+ sig
->cnvcsw
;
1155 p
->nivcsw
+ sig
->nivcsw
+ sig
->cnivcsw
;
1157 task_io_get_inblock(p
) +
1158 sig
->inblock
+ sig
->cinblock
;
1160 task_io_get_oublock(p
) +
1161 sig
->oublock
+ sig
->coublock
;
1162 maxrss
= max(sig
->maxrss
, sig
->cmaxrss
);
1163 if (psig
->cmaxrss
< maxrss
)
1164 psig
->cmaxrss
= maxrss
;
1165 task_io_accounting_add(&psig
->ioac
, &p
->ioac
);
1166 task_io_accounting_add(&psig
->ioac
, &sig
->ioac
);
1167 write_sequnlock_irq(&psig
->stats_lock
);
1171 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1172 status
= (p
->signal
->flags
& SIGNAL_GROUP_EXIT
)
1173 ? p
->signal
->group_exit_code
: p
->exit_code
;
1174 wo
->wo_stat
= status
;
1176 if (state
== EXIT_TRACE
) {
1177 write_lock_irq(&tasklist_lock
);
1178 /* We dropped tasklist, ptracer could die and untrace */
1181 /* If parent wants a zombie, don't release it now */
1182 state
= EXIT_ZOMBIE
;
1183 if (do_notify_parent(p
, p
->exit_signal
))
1185 p
->exit_state
= state
;
1186 write_unlock_irq(&tasklist_lock
);
1188 if (state
== EXIT_DEAD
)
1192 infop
= wo
->wo_info
;
1194 if ((status
& 0x7f) == 0) {
1195 infop
->cause
= CLD_EXITED
;
1196 infop
->status
= status
>> 8;
1198 infop
->cause
= (status
& 0x80) ? CLD_DUMPED
: CLD_KILLED
;
1199 infop
->status
= status
& 0x7f;
1208 static int *task_stopped_code(struct task_struct
*p
, bool ptrace
)
1211 if (task_is_traced(p
) && !(p
->jobctl
& JOBCTL_LISTENING
))
1212 return &p
->exit_code
;
1214 if (p
->signal
->flags
& SIGNAL_STOP_STOPPED
)
1215 return &p
->signal
->group_exit_code
;
1221 * wait_task_stopped - Wait for %TASK_STOPPED or %TASK_TRACED
1223 * @ptrace: is the wait for ptrace
1224 * @p: task to wait for
1226 * Handle sys_wait4() work for %p in state %TASK_STOPPED or %TASK_TRACED.
1229 * read_lock(&tasklist_lock), which is released if return value is
1230 * non-zero. Also, grabs and releases @p->sighand->siglock.
1233 * 0 if wait condition didn't exist and search for other wait conditions
1234 * should continue. Non-zero return, -errno on failure and @p's pid on
1235 * success, implies that tasklist_lock is released and wait condition
1236 * search should terminate.
1238 static int wait_task_stopped(struct wait_opts
*wo
,
1239 int ptrace
, struct task_struct
*p
)
1241 struct waitid_info
*infop
;
1242 int exit_code
, *p_code
, why
;
1243 uid_t uid
= 0; /* unneeded, required by compiler */
1247 * Traditionally we see ptrace'd stopped tasks regardless of options.
1249 if (!ptrace
&& !(wo
->wo_flags
& WUNTRACED
))
1252 if (!task_stopped_code(p
, ptrace
))
1256 spin_lock_irq(&p
->sighand
->siglock
);
1258 p_code
= task_stopped_code(p
, ptrace
);
1259 if (unlikely(!p_code
))
1262 exit_code
= *p_code
;
1266 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1269 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1271 spin_unlock_irq(&p
->sighand
->siglock
);
1276 * Now we are pretty sure this task is interesting.
1277 * Make sure it doesn't get reaped out from under us while we
1278 * give up the lock and then examine it below. We don't want to
1279 * keep holding onto the tasklist_lock while we call getrusage and
1280 * possibly take page faults for user memory.
1283 pid
= task_pid_vnr(p
);
1284 why
= ptrace
? CLD_TRAPPED
: CLD_STOPPED
;
1285 read_unlock(&tasklist_lock
);
1286 sched_annotate_sleep();
1288 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1291 if (likely(!(wo
->wo_flags
& WNOWAIT
)))
1292 wo
->wo_stat
= (exit_code
<< 8) | 0x7f;
1294 infop
= wo
->wo_info
;
1297 infop
->status
= exit_code
;
1305 * Handle do_wait work for one task in a live, non-stopped state.
1306 * read_lock(&tasklist_lock) on entry. If we return zero, we still hold
1307 * the lock and this task is uninteresting. If we return nonzero, we have
1308 * released the lock and the system call should return.
1310 static int wait_task_continued(struct wait_opts
*wo
, struct task_struct
*p
)
1312 struct waitid_info
*infop
;
1316 if (!unlikely(wo
->wo_flags
& WCONTINUED
))
1319 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
))
1322 spin_lock_irq(&p
->sighand
->siglock
);
1323 /* Re-check with the lock held. */
1324 if (!(p
->signal
->flags
& SIGNAL_STOP_CONTINUED
)) {
1325 spin_unlock_irq(&p
->sighand
->siglock
);
1328 if (!unlikely(wo
->wo_flags
& WNOWAIT
))
1329 p
->signal
->flags
&= ~SIGNAL_STOP_CONTINUED
;
1330 uid
= from_kuid_munged(current_user_ns(), task_uid(p
));
1331 spin_unlock_irq(&p
->sighand
->siglock
);
1333 pid
= task_pid_vnr(p
);
1335 read_unlock(&tasklist_lock
);
1336 sched_annotate_sleep();
1338 getrusage(p
, RUSAGE_BOTH
, wo
->wo_rusage
);
1341 infop
= wo
->wo_info
;
1343 wo
->wo_stat
= 0xffff;
1345 infop
->cause
= CLD_CONTINUED
;
1348 infop
->status
= SIGCONT
;
1354 * Consider @p for a wait by @parent.
1356 * -ECHILD should be in ->notask_error before the first call.
1357 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1358 * Returns zero if the search for a child should continue;
1359 * then ->notask_error is 0 if @p is an eligible child,
1362 static int wait_consider_task(struct wait_opts
*wo
, int ptrace
,
1363 struct task_struct
*p
)
1366 * We can race with wait_task_zombie() from another thread.
1367 * Ensure that EXIT_ZOMBIE -> EXIT_DEAD/EXIT_TRACE transition
1368 * can't confuse the checks below.
1370 int exit_state
= READ_ONCE(p
->exit_state
);
1373 if (unlikely(exit_state
== EXIT_DEAD
))
1376 ret
= eligible_child(wo
, ptrace
, p
);
1380 if (unlikely(exit_state
== EXIT_TRACE
)) {
1382 * ptrace == 0 means we are the natural parent. In this case
1383 * we should clear notask_error, debugger will notify us.
1385 if (likely(!ptrace
))
1386 wo
->notask_error
= 0;
1390 if (likely(!ptrace
) && unlikely(p
->ptrace
)) {
1392 * If it is traced by its real parent's group, just pretend
1393 * the caller is ptrace_do_wait() and reap this child if it
1396 * This also hides group stop state from real parent; otherwise
1397 * a single stop can be reported twice as group and ptrace stop.
1398 * If a ptracer wants to distinguish these two events for its
1399 * own children it should create a separate process which takes
1400 * the role of real parent.
1402 if (!ptrace_reparented(p
))
1407 if (exit_state
== EXIT_ZOMBIE
) {
1408 /* we don't reap group leaders with subthreads */
1409 if (!delay_group_leader(p
)) {
1411 * A zombie ptracee is only visible to its ptracer.
1412 * Notification and reaping will be cascaded to the
1413 * real parent when the ptracer detaches.
1415 if (unlikely(ptrace
) || likely(!p
->ptrace
))
1416 return wait_task_zombie(wo
, p
);
1420 * Allow access to stopped/continued state via zombie by
1421 * falling through. Clearing of notask_error is complex.
1425 * If WEXITED is set, notask_error should naturally be
1426 * cleared. If not, subset of WSTOPPED|WCONTINUED is set,
1427 * so, if there are live subthreads, there are events to
1428 * wait for. If all subthreads are dead, it's still safe
1429 * to clear - this function will be called again in finite
1430 * amount time once all the subthreads are released and
1431 * will then return without clearing.
1435 * Stopped state is per-task and thus can't change once the
1436 * target task dies. Only continued and exited can happen.
1437 * Clear notask_error if WCONTINUED | WEXITED.
1439 if (likely(!ptrace
) || (wo
->wo_flags
& (WCONTINUED
| WEXITED
)))
1440 wo
->notask_error
= 0;
1443 * @p is alive and it's gonna stop, continue or exit, so
1444 * there always is something to wait for.
1446 wo
->notask_error
= 0;
1450 * Wait for stopped. Depending on @ptrace, different stopped state
1451 * is used and the two don't interact with each other.
1453 ret
= wait_task_stopped(wo
, ptrace
, p
);
1458 * Wait for continued. There's only one continued state and the
1459 * ptracer can consume it which can confuse the real parent. Don't
1460 * use WCONTINUED from ptracer. You don't need or want it.
1462 return wait_task_continued(wo
, p
);
1466 * Do the work of do_wait() for one thread in the group, @tsk.
1468 * -ECHILD should be in ->notask_error before the first call.
1469 * Returns nonzero for a final return, when we have unlocked tasklist_lock.
1470 * Returns zero if the search for a child should continue; then
1471 * ->notask_error is 0 if there were any eligible children,
1474 static int do_wait_thread(struct wait_opts
*wo
, struct task_struct
*tsk
)
1476 struct task_struct
*p
;
1478 list_for_each_entry(p
, &tsk
->children
, sibling
) {
1479 int ret
= wait_consider_task(wo
, 0, p
);
1488 static int ptrace_do_wait(struct wait_opts
*wo
, struct task_struct
*tsk
)
1490 struct task_struct
*p
;
1492 list_for_each_entry(p
, &tsk
->ptraced
, ptrace_entry
) {
1493 int ret
= wait_consider_task(wo
, 1, p
);
1502 bool pid_child_should_wake(struct wait_opts
*wo
, struct task_struct
*p
)
1504 if (!eligible_pid(wo
, p
))
1507 if ((wo
->wo_flags
& __WNOTHREAD
) && wo
->child_wait
.private != p
->parent
)
1513 static int child_wait_callback(wait_queue_entry_t
*wait
, unsigned mode
,
1514 int sync
, void *key
)
1516 struct wait_opts
*wo
= container_of(wait
, struct wait_opts
,
1518 struct task_struct
*p
= key
;
1520 if (pid_child_should_wake(wo
, p
))
1521 return default_wake_function(wait
, mode
, sync
, key
);
1526 void __wake_up_parent(struct task_struct
*p
, struct task_struct
*parent
)
1528 __wake_up_sync_key(&parent
->signal
->wait_chldexit
,
1529 TASK_INTERRUPTIBLE
, p
);
1532 static bool is_effectively_child(struct wait_opts
*wo
, bool ptrace
,
1533 struct task_struct
*target
)
1535 struct task_struct
*parent
=
1536 !ptrace
? target
->real_parent
: target
->parent
;
1538 return current
== parent
|| (!(wo
->wo_flags
& __WNOTHREAD
) &&
1539 same_thread_group(current
, parent
));
1543 * Optimization for waiting on PIDTYPE_PID. No need to iterate through child
1544 * and tracee lists to find the target task.
1546 static int do_wait_pid(struct wait_opts
*wo
)
1549 struct task_struct
*target
;
1553 target
= pid_task(wo
->wo_pid
, PIDTYPE_TGID
);
1554 if (target
&& is_effectively_child(wo
, ptrace
, target
)) {
1555 retval
= wait_consider_task(wo
, ptrace
, target
);
1561 target
= pid_task(wo
->wo_pid
, PIDTYPE_PID
);
1562 if (target
&& target
->ptrace
&&
1563 is_effectively_child(wo
, ptrace
, target
)) {
1564 retval
= wait_consider_task(wo
, ptrace
, target
);
1572 long __do_wait(struct wait_opts
*wo
)
1577 * If there is nothing that can match our criteria, just get out.
1578 * We will clear ->notask_error to zero if we see any child that
1579 * might later match our criteria, even if we are not able to reap
1582 wo
->notask_error
= -ECHILD
;
1583 if ((wo
->wo_type
< PIDTYPE_MAX
) &&
1584 (!wo
->wo_pid
|| !pid_has_task(wo
->wo_pid
, wo
->wo_type
)))
1587 read_lock(&tasklist_lock
);
1589 if (wo
->wo_type
== PIDTYPE_PID
) {
1590 retval
= do_wait_pid(wo
);
1594 struct task_struct
*tsk
= current
;
1597 retval
= do_wait_thread(wo
, tsk
);
1601 retval
= ptrace_do_wait(wo
, tsk
);
1605 if (wo
->wo_flags
& __WNOTHREAD
)
1607 } while_each_thread(current
, tsk
);
1609 read_unlock(&tasklist_lock
);
1612 retval
= wo
->notask_error
;
1613 if (!retval
&& !(wo
->wo_flags
& WNOHANG
))
1614 return -ERESTARTSYS
;
1619 static long do_wait(struct wait_opts
*wo
)
1623 trace_sched_process_wait(wo
->wo_pid
);
1625 init_waitqueue_func_entry(&wo
->child_wait
, child_wait_callback
);
1626 wo
->child_wait
.private = current
;
1627 add_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1630 set_current_state(TASK_INTERRUPTIBLE
);
1631 retval
= __do_wait(wo
);
1632 if (retval
!= -ERESTARTSYS
)
1634 if (signal_pending(current
))
1639 __set_current_state(TASK_RUNNING
);
1640 remove_wait_queue(¤t
->signal
->wait_chldexit
, &wo
->child_wait
);
1644 int kernel_waitid_prepare(struct wait_opts
*wo
, int which
, pid_t upid
,
1645 struct waitid_info
*infop
, int options
,
1648 unsigned int f_flags
= 0;
1649 struct pid
*pid
= NULL
;
1652 if (options
& ~(WNOHANG
|WNOWAIT
|WEXITED
|WSTOPPED
|WCONTINUED
|
1653 __WNOTHREAD
|__WCLONE
|__WALL
))
1655 if (!(options
& (WEXITED
|WSTOPPED
|WCONTINUED
)))
1667 pid
= find_get_pid(upid
);
1670 type
= PIDTYPE_PGID
;
1675 pid
= find_get_pid(upid
);
1677 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1684 pid
= pidfd_get_pid(upid
, &f_flags
);
1686 return PTR_ERR(pid
);
1695 wo
->wo_flags
= options
;
1696 wo
->wo_info
= infop
;
1698 if (f_flags
& O_NONBLOCK
)
1699 wo
->wo_flags
|= WNOHANG
;
1704 static long kernel_waitid(int which
, pid_t upid
, struct waitid_info
*infop
,
1705 int options
, struct rusage
*ru
)
1707 struct wait_opts wo
;
1710 ret
= kernel_waitid_prepare(&wo
, which
, upid
, infop
, options
, ru
);
1715 if (!ret
&& !(options
& WNOHANG
) && (wo
.wo_flags
& WNOHANG
))
1722 SYSCALL_DEFINE5(waitid
, int, which
, pid_t
, upid
, struct siginfo __user
*,
1723 infop
, int, options
, struct rusage __user
*, ru
)
1726 struct waitid_info info
= {.status
= 0};
1727 long err
= kernel_waitid(which
, upid
, &info
, options
, ru
? &r
: NULL
);
1733 if (ru
&& copy_to_user(ru
, &r
, sizeof(struct rusage
)))
1739 if (!user_write_access_begin(infop
, sizeof(*infop
)))
1742 unsafe_put_user(signo
, &infop
->si_signo
, Efault
);
1743 unsafe_put_user(0, &infop
->si_errno
, Efault
);
1744 unsafe_put_user(info
.cause
, &infop
->si_code
, Efault
);
1745 unsafe_put_user(info
.pid
, &infop
->si_pid
, Efault
);
1746 unsafe_put_user(info
.uid
, &infop
->si_uid
, Efault
);
1747 unsafe_put_user(info
.status
, &infop
->si_status
, Efault
);
1748 user_write_access_end();
1751 user_write_access_end();
1755 long kernel_wait4(pid_t upid
, int __user
*stat_addr
, int options
,
1758 struct wait_opts wo
;
1759 struct pid
*pid
= NULL
;
1763 if (options
& ~(WNOHANG
|WUNTRACED
|WCONTINUED
|
1764 __WNOTHREAD
|__WCLONE
|__WALL
))
1767 /* -INT_MIN is not defined */
1768 if (upid
== INT_MIN
)
1773 else if (upid
< 0) {
1774 type
= PIDTYPE_PGID
;
1775 pid
= find_get_pid(-upid
);
1776 } else if (upid
== 0) {
1777 type
= PIDTYPE_PGID
;
1778 pid
= get_task_pid(current
, PIDTYPE_PGID
);
1779 } else /* upid > 0 */ {
1781 pid
= find_get_pid(upid
);
1786 wo
.wo_flags
= options
| WEXITED
;
1792 if (ret
> 0 && stat_addr
&& put_user(wo
.wo_stat
, stat_addr
))
1798 int kernel_wait(pid_t pid
, int *stat
)
1800 struct wait_opts wo
= {
1801 .wo_type
= PIDTYPE_PID
,
1802 .wo_pid
= find_get_pid(pid
),
1803 .wo_flags
= WEXITED
,
1808 if (ret
> 0 && wo
.wo_stat
)
1814 SYSCALL_DEFINE4(wait4
, pid_t
, upid
, int __user
*, stat_addr
,
1815 int, options
, struct rusage __user
*, ru
)
1818 long err
= kernel_wait4(upid
, stat_addr
, options
, ru
? &r
: NULL
);
1821 if (ru
&& copy_to_user(ru
, &r
, sizeof(struct rusage
)))
1827 #ifdef __ARCH_WANT_SYS_WAITPID
1830 * sys_waitpid() remains for compatibility. waitpid() should be
1831 * implemented by calling sys_wait4() from libc.a.
1833 SYSCALL_DEFINE3(waitpid
, pid_t
, pid
, int __user
*, stat_addr
, int, options
)
1835 return kernel_wait4(pid
, stat_addr
, options
, NULL
);
1840 #ifdef CONFIG_COMPAT
1841 COMPAT_SYSCALL_DEFINE4(wait4
,
1843 compat_uint_t __user
*, stat_addr
,
1845 struct compat_rusage __user
*, ru
)
1848 long err
= kernel_wait4(pid
, stat_addr
, options
, ru
? &r
: NULL
);
1850 if (ru
&& put_compat_rusage(&r
, ru
))
1856 COMPAT_SYSCALL_DEFINE5(waitid
,
1857 int, which
, compat_pid_t
, pid
,
1858 struct compat_siginfo __user
*, infop
, int, options
,
1859 struct compat_rusage __user
*, uru
)
1862 struct waitid_info info
= {.status
= 0};
1863 long err
= kernel_waitid(which
, pid
, &info
, options
, uru
? &ru
: NULL
);
1869 /* kernel_waitid() overwrites everything in ru */
1870 if (COMPAT_USE_64BIT_TIME
)
1871 err
= copy_to_user(uru
, &ru
, sizeof(ru
));
1873 err
= put_compat_rusage(&ru
, uru
);
1882 if (!user_write_access_begin(infop
, sizeof(*infop
)))
1885 unsafe_put_user(signo
, &infop
->si_signo
, Efault
);
1886 unsafe_put_user(0, &infop
->si_errno
, Efault
);
1887 unsafe_put_user(info
.cause
, &infop
->si_code
, Efault
);
1888 unsafe_put_user(info
.pid
, &infop
->si_pid
, Efault
);
1889 unsafe_put_user(info
.uid
, &infop
->si_uid
, Efault
);
1890 unsafe_put_user(info
.status
, &infop
->si_status
, Efault
);
1891 user_write_access_end();
1894 user_write_access_end();
1900 * This needs to be __function_aligned as GCC implicitly makes any
1901 * implementation of abort() cold and drops alignment specified by
1902 * -falign-functions=N.
1904 * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345#c11
1906 __weak __function_aligned
void abort(void)
1910 /* if that doesn't kill us, halt */
1911 panic("Oops failed to kill thread");
1913 EXPORT_SYMBOL(abort
);