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34 * @(#)kern_exit.c 8.7 (Berkeley) 2/12/94
35 * $FreeBSD: src/sys/kern/kern_exit.c,v 1.92.2.11 2003/01/13 22:51:16 dillon Exp $
38 #include "opt_compat.h"
39 #include "opt_ktrace.h"
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/sysproto.h>
44 #include <sys/kernel.h>
45 #include <sys/malloc.h>
47 #include <sys/ktrace.h>
48 #include <sys/pioctl.h>
51 #include <sys/vnode.h>
52 #include <sys/resourcevar.h>
53 #include <sys/signalvar.h>
54 #include <sys/taskqueue.h>
55 #include <sys/ptrace.h>
56 #include <sys/acct.h> /* for acct_process() function prototype */
57 #include <sys/filedesc.h>
61 #include <sys/kern_syscall.h>
62 #include <sys/unistd.h>
63 #include <sys/eventhandler.h>
64 #include <sys/dsched.h>
67 #include <vm/vm_param.h>
70 #include <vm/vm_map.h>
71 #include <vm/vm_extern.h>
74 #include <sys/refcount.h>
75 #include <sys/thread2.h>
76 #include <sys/sysref2.h>
77 #include <sys/mplock2.h>
79 #include <machine/vmm.h>
81 static void reaplwps(void *context, int dummy);
82 static void reaplwp(struct lwp *lp);
83 static void killlwps(struct lwp *lp);
85 static MALLOC_DEFINE(M_ATEXIT, "atexit", "atexit callback");
88 * callout list for things to do at exit time
92 TAILQ_ENTRY(exitlist) next;
95 TAILQ_HEAD(exit_list_head, exitlist);
96 static struct exit_list_head exit_list = TAILQ_HEAD_INITIALIZER(exit_list);
101 static struct task *deadlwp_task[MAXCPU];
102 static struct lwplist deadlwp_list[MAXCPU];
103 static struct lwkt_token deadlwp_token[MAXCPU];
109 * SYS_EXIT_ARGS(int rval)
112 sys_exit(struct exit_args *uap)
114 exit1(W_EXITCODE(uap->rval, 0));
120 * Death of a lwp or process with optional bells and whistles.
123 sys_extexit(struct extexit_args *uap)
125 struct proc *p = curproc;
129 action = EXTEXIT_ACTION(uap->how);
130 who = EXTEXIT_WHO(uap->how);
132 /* Check parameters before we might perform some action */
145 error = copyout(&uap->status, uap->addr, sizeof(uap->status));
153 lwkt_gettoken(&p->p_token);
158 * Be sure only to perform a simple lwp exit if there is at
159 * least one more lwp in the proc, which will call exit1()
160 * later, otherwise the proc will be an UNDEAD and not even a
163 if (p->p_nthreads > 1) {
164 lwp_exit(0, NULL); /* called w/ p_token held */
167 /* else last lwp in proc: do the real thing */
169 default: /* to help gcc */
171 lwkt_reltoken(&p->p_token);
172 exit1(W_EXITCODE(uap->status, 0));
177 lwkt_reltoken(&p->p_token); /* safety */
181 * Kill all lwps associated with the current process except the
182 * current lwp. Return an error if we race another thread trying to
183 * do the same thing and lose the race.
185 * If forexec is non-zero the current thread and process flags are
186 * cleaned up so they can be reused.
188 * Caller must hold curproc->p_token
191 killalllwps(int forexec)
193 struct lwp *lp = curthread->td_lwp;
194 struct proc *p = lp->lwp_proc;
198 * Interlock against P_WEXIT. Only one of the process's thread
199 * is allowed to do the master exit.
201 if (p->p_flags & P_WEXIT)
203 p->p_flags |= P_WEXIT;
206 * Set temporary stopped state in case we are racing a coredump.
207 * Otherwise the coredump may hang forever.
209 if (lp->lwp_mpflags & LWP_MP_WSTOP) {
212 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WSTOP);
215 wakeup(&p->p_nstopped);
219 * Interlock with LWP_MP_WEXIT and kill any remaining LWPs
221 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
222 if (p->p_nthreads > 1)
226 * Undo temporary stopped state
229 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_WSTOP);
234 * If doing this for an exec, clean up the remaining thread
235 * (us) for continuing operation after all the other threads
239 atomic_clear_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
240 p->p_flags &= ~P_WEXIT;
246 * Kill all LWPs except the current one. Do not try to signal
247 * LWPs which have exited on their own or have already been
251 killlwps(struct lwp *lp)
253 struct proc *p = lp->lwp_proc;
257 * Kill the remaining LWPs. We must send the signal before setting
258 * LWP_MP_WEXIT. The setting of WEXIT is optional but helps reduce
259 * races. tlp must be held across the call as it might block and
260 * allow the target lwp to rip itself out from under our loop.
262 FOREACH_LWP_IN_PROC(tlp, p) {
264 lwkt_gettoken(&tlp->lwp_token);
265 if ((tlp->lwp_mpflags & LWP_MP_WEXIT) == 0) {
266 lwpsignal(p, tlp, SIGKILL);
267 atomic_set_int(&tlp->lwp_mpflags, LWP_MP_WEXIT);
269 lwkt_reltoken(&tlp->lwp_token);
274 * Wait for everything to clear out.
276 while (p->p_nthreads > 1)
277 tsleep(&p->p_nthreads, 0, "killlwps", 0);
281 * Exit: deallocate address space and other resources, change proc state
282 * to zombie, and unlink proc from allproc and parent's lists. Save exit
283 * status and rusage for wait(). Check for child processes and orphan them.
288 struct thread *td = curthread;
289 struct proc *p = td->td_proc;
290 struct lwp *lp = td->td_lwp;
294 struct sysreaper *reap;
300 lwkt_gettoken(&p->p_token);
303 kprintf("init died (signal %d, exit %d)\n",
304 WTERMSIG(rv), WEXITSTATUS(rv));
305 panic("Going nowhere without my init!");
307 varsymset_clean(&p->p_varsymset);
308 lockuninit(&p->p_varsymset.vx_lock);
311 * Kill all lwps associated with the current process, return an
312 * error if we race another thread trying to do the same thing
315 error = killalllwps(0);
321 /* are we a task leader? */
322 if (p == p->p_leader) {
323 struct kill_args killArgs;
324 killArgs.signum = SIGKILL;
327 killArgs.pid = q->p_pid;
329 * The interface for kill is better
330 * than the internal signal
336 tsleep((caddr_t)p, 0, "exit1", 0);
342 STOPEVENT(p, S_EXIT, rv);
343 p->p_flags |= P_POSTEXIT; /* stop procfs stepping */
346 * Check if any loadable modules need anything done at process exit.
347 * e.g. SYSV IPC stuff
348 * XXX what if one of these generates an error?
351 EVENTHANDLER_INVOKE(process_exit, p);
354 * XXX: imho, the eventhandler stuff is much cleaner than this.
355 * Maybe we should move everything to use eventhandler.
357 TAILQ_FOREACH(ep, &exit_list, next)
360 if (p->p_flags & P_PROFIL)
363 SIGEMPTYSET(p->p_siglist);
364 SIGEMPTYSET(lp->lwp_siglist);
365 if (timevalisset(&p->p_realtimer.it_value))
366 callout_stop_sync(&p->p_ithandle);
369 * Reset any sigio structures pointing to us as a result of
370 * F_SETOWN with our pid.
372 funsetownlst(&p->p_sigiolst);
375 * Close open files and release open-file table.
380 if (p->p_leader->p_peers) {
382 while(q->p_peers != p)
384 q->p_peers = p->p_peers;
385 wakeup((caddr_t)p->p_leader);
389 * XXX Shutdown SYSV semaphores
393 KKASSERT(p->p_numposixlocks == 0);
395 /* The next two chunks should probably be moved to vmspace_exit. */
399 * Clean up data related to virtual kernel operation. Clean up
400 * any vkernel context related to the current lwp now so we can
404 vkernel_lwp_exit(lp);
409 * Release the user portion of address space. The exitbump prevents
410 * the vmspace from being completely eradicated (using holdcnt).
411 * This releases references to vnodes, which could cause I/O if the
412 * file has been unlinked. We need to do this early enough that
413 * we can still sleep.
415 * We can't free the entire vmspace as the kernel stack may be mapped
416 * within that space also.
418 * Processes sharing the same vmspace may exit in one order, and
419 * get cleaned up by vmspace_exit() in a different order. The
420 * last exiting process to reach this point releases as much of
421 * the environment as it can, and the last process cleaned up
422 * by vmspace_exit() (which decrements exitingcnt) cleans up the
427 if (SESS_LEADER(p)) {
428 struct session *sp = p->p_session;
432 * We are the controlling process. Signal the
433 * foreground process group, drain the controlling
434 * terminal, and revoke access to the controlling
437 * NOTE: while waiting for the process group to exit
438 * it is possible that one of the processes in the
439 * group will revoke the tty, so the ttyclosesession()
440 * function will re-check sp->s_ttyvp.
442 if (sp->s_ttyp && (sp->s_ttyp->t_session == sp)) {
443 if (sp->s_ttyp->t_pgrp)
444 pgsignal(sp->s_ttyp->t_pgrp, SIGHUP, 1);
446 ttyclosesession(sp, 1); /* also revoke */
449 * Release the tty. If someone has it open via
450 * /dev/tty then close it (since they no longer can
451 * once we've NULL'd it out).
453 ttyclosesession(sp, 0);
456 * s_ttyp is not zero'd; we use this to indicate
457 * that the session once had a controlling terminal.
458 * (for logging and informational purposes)
463 fixjobc(p, p->p_pgrp, 0);
464 (void)acct_process(p);
470 ktrdestroy(&p->p_tracenode);
474 * Release reference to text vnode
476 if ((vtmp = p->p_textvp) != NULL) {
481 /* Release namecache handle to text file */
482 if (p->p_textnch.ncp)
483 cache_drop(&p->p_textnch);
486 * We have to handle PPWAIT here or proc_move_allproc_zombie()
487 * will block on the PHOLD() the parent is doing.
489 * We are using the flag as an interlock so an atomic op is
490 * necessary to synchronize with the parent's cpu.
492 if (p->p_flags & P_PPWAIT) {
493 if (p->p_pptr && p->p_pptr->p_upmap)
494 p->p_pptr->p_upmap->invfork = 0;
495 atomic_clear_int(&p->p_flags, P_PPWAIT);
500 * Move the process to the zombie list. This will block
501 * until the process p_lock count reaches 0. The process will
502 * not be reaped until TDF_EXITING is set by cpu_thread_exit(),
503 * which is called from cpu_proc_exit().
505 * Interlock against waiters using p_waitgen. We increment
506 * p_waitgen after completing the move of our process to the
509 * WARNING: pp becomes stale when we block, clear it now as a
512 proc_move_allproc_zombie(p);
514 atomic_add_long(&pp->p_waitgen, 1);
518 * release controlled reaper for exit if we own it and return the
519 * remaining reaper (the one for us), which we will drop after we
522 reap = reaper_exit(p);
525 * Reparent all of this process's children to the init process or
526 * to the designated reaper. We must hold the reaper's p_token in
527 * order to safely mess with p_children.
529 * We already hold p->p_token (to remove the children from our list).
532 q = LIST_FIRST(&p->p_children);
534 reproc = reaper_get(reap);
535 lwkt_gettoken(&reproc->p_token);
536 while ((q = LIST_FIRST(&p->p_children)) != NULL) {
538 lwkt_gettoken(&q->p_token);
539 if (q != LIST_FIRST(&p->p_children)) {
540 lwkt_reltoken(&q->p_token);
544 LIST_REMOVE(q, p_sibling);
545 LIST_INSERT_HEAD(&reproc->p_children, q, p_sibling);
547 q->p_sigparent = SIGCHLD;
550 * Traced processes are killed
551 * since their existence means someone is screwing up.
553 if (q->p_flags & P_TRACED) {
554 q->p_flags &= ~P_TRACED;
557 lwkt_reltoken(&q->p_token);
560 lwkt_reltoken(&reproc->p_token);
565 * Save exit status and final rusage info, adding in child rusage
566 * info and self times.
568 calcru_proc(p, &p->p_ru);
569 ruadd(&p->p_ru, &p->p_cru);
572 * notify interested parties of our demise.
574 KNOTE(&p->p_klist, NOTE_EXIT);
577 * Notify parent that we're gone. If parent has the PS_NOCLDWAIT
578 * flag set, or if the handler is set to SIG_IGN, notify the reaper
579 * instead (it will handle this situation).
581 * NOTE: The reaper can still be the parent process.
585 if (p->p_pptr->p_sigacts->ps_flag & (PS_NOCLDWAIT | PS_CLDSIGIGN)) {
587 reproc = reaper_get(reap);
588 proc_reparent(p, reproc);
596 * Signal (possibly new) parent.
600 if (p->p_sigparent && pp != initproc) {
601 int sig = p->p_sigparent;
603 if (sig != SIGUSR1 && sig != SIGCHLD)
607 ksignal(pp, SIGCHLD);
609 p->p_flags &= ~P_TRACED;
613 * cpu_exit is responsible for clearing curproc, since
614 * it is heavily integrated with the thread/switching sequence.
616 * Other substructures are freed from wait().
621 * Finally, call machine-dependent code to release as many of the
622 * lwp's resources as we can and halt execution of this thread.
624 * pp is a wild pointer now but still the correct wakeup() target.
625 * lwp_exit() only uses it to send the wakeup() signal to the likely
626 * parent. Any reparenting race that occurs will get a signal
627 * automatically and not be an issue.
633 * Eventually called by every exiting LWP
635 * p->p_token must be held. mplock may be held and will be released.
638 lwp_exit(int masterexit, void *waddr)
640 struct thread *td = curthread;
641 struct lwp *lp = td->td_lwp;
642 struct proc *p = lp->lwp_proc;
646 * Release the current user process designation on the process so
647 * the userland scheduler can work in someone else.
649 p->p_usched->release_curproc(lp);
652 * lwp_exit() may be called without setting LWP_MP_WEXIT, so
653 * make sure it is set here.
655 ASSERT_LWKT_TOKEN_HELD(&p->p_token);
656 atomic_set_int(&lp->lwp_mpflags, LWP_MP_WEXIT);
659 * Clean up any virtualization
662 vkernel_lwp_exit(lp);
668 * Clean up select/poll support
670 kqueue_terminate(&lp->lwp_kqueue);
673 * Clean up any syscall-cached ucred
676 crfree(td->td_ucred);
681 * Nobody actually wakes us when the lock
682 * count reaches zero, so just wait one tick.
684 while (lp->lwp_lock > 0)
685 tsleep(lp, 0, "lwpexit", 1);
687 /* Hand down resource usage to our proc */
688 ruadd(&p->p_ru, &lp->lwp_ru);
691 * If we don't hold the process until the LWP is reaped wait*()
692 * may try to dispose of its vmspace before all the LWPs have
693 * actually terminated.
698 * Do any remaining work that might block on us. We should be
699 * coded such that further blocking is ok after decrementing
700 * p_nthreads but don't take the chance.
702 dsched_exit_thread(td);
703 biosched_done(curthread);
706 * We have to use the reaper for all the LWPs except the one doing
707 * the master exit. The LWP doing the master exit can just be
708 * left on p_lwps and the process reaper will deal with it
709 * synchronously, which is much faster.
711 * Wakeup anyone waiting on p_nthreads to drop to 1 or 0.
713 * The process is left held until the reaper calls lwp_dispose() on
714 * the lp (after calling lwp_wait()).
716 if (masterexit == 0) {
719 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
721 if ((p->p_flags & P_MAYBETHREADED) && p->p_nthreads <= 1)
723 lwkt_gettoken(&deadlwp_token[cpu]);
724 LIST_INSERT_HEAD(&deadlwp_list[cpu], lp, u.lwp_reap_entry);
725 taskqueue_enqueue(taskqueue_thread[cpu], deadlwp_task[cpu]);
726 lwkt_reltoken(&deadlwp_token[cpu]);
729 if ((p->p_flags & P_MAYBETHREADED) && p->p_nthreads <= 1)
734 * We no longer need p_token.
736 * Tell the userland scheduler that we are going away
738 lwkt_reltoken(&p->p_token);
739 p->p_usched->heuristic_exiting(lp, p);
742 * Issue late wakeups after releasing our token to give us a chance
743 * to deschedule and switch away before another cpu in a wait*()
744 * reaps us. This is done as late as possible to reduce contention.
747 wakeup(&p->p_nthreads);
755 * Wait until a lwp is completely dead. The final interlock in this drama
756 * is when TDF_EXITING is set in cpu_thread_exit() just before the final
759 * At the point TDF_EXITING is set a complete exit is accomplished when
760 * TDF_RUNNING and TDF_PREEMPT_LOCK are both clear. td_mpflags has two
761 * post-switch interlock flags that can be used to wait for the TDF_
764 * Returns non-zero on success, and zero if the caller needs to retry
768 lwp_wait(struct lwp *lp)
770 struct thread *td = lp->lwp_thread;
773 KKASSERT(lwkt_preempted_proc() != lp);
776 * This bit of code uses the thread destruction interlock
777 * managed by lwkt_switch_return() to wait for the lwp's
778 * thread to completely disengage.
780 * It is possible for us to race another cpu core so we
781 * have to do this correctly.
784 mpflags = td->td_mpflags;
786 if (mpflags & TDF_MP_EXITSIG)
788 tsleep_interlock(td, 0);
789 if (atomic_cmpset_int(&td->td_mpflags, mpflags,
790 mpflags | TDF_MP_EXITWAIT)) {
791 tsleep(td, PINTERLOCKED, "lwpxt", 0);
796 * We've already waited for the core exit but there can still
797 * be other refs from e.g. process scans and such.
799 if (lp->lwp_lock > 0) {
800 tsleep(lp, 0, "lwpwait1", 1);
804 tsleep(td, 0, "lwpwait2", 1);
809 * Now that we have the thread destruction interlock these flags
810 * really should already be cleaned up, keep a check for safety.
812 * We can't rip its stack out from under it until TDF_EXITING is
813 * set and both TDF_RUNNING and TDF_PREEMPT_LOCK are clear.
814 * TDF_PREEMPT_LOCK must be checked because TDF_RUNNING
815 * will be cleared temporarily if a thread gets preempted.
817 while ((td->td_flags & (TDF_RUNNING |
820 TDF_EXITING)) != TDF_EXITING) {
821 tsleep(lp, 0, "lwpwait3", 1);
825 KASSERT((td->td_flags & (TDF_RUNQ|TDF_TSLEEPQ)) == 0,
826 ("lwp_wait: td %p (%s) still on run or sleep queue",
832 * Release the resources associated with a lwp.
833 * The lwp must be completely dead.
836 lwp_dispose(struct lwp *lp)
838 struct thread *td = lp->lwp_thread;
840 KKASSERT(lwkt_preempted_proc() != lp);
841 KKASSERT(td->td_refs == 0);
842 KKASSERT((td->td_flags & (TDF_RUNNING |
845 TDF_EXITING)) == TDF_EXITING);
852 lp->lwp_thread = NULL;
853 lwkt_free_thread(td);
859 sys_wait4(struct wait_args *uap)
861 struct rusage rusage;
864 error = kern_wait(uap->pid, (uap->status ? &status : NULL),
865 uap->options, (uap->rusage ? &rusage : NULL),
866 &uap->sysmsg_result);
868 if (error == 0 && uap->status)
869 error = copyout(&status, uap->status, sizeof(*uap->status));
870 if (error == 0 && uap->rusage)
871 error = copyout(&rusage, uap->rusage, sizeof(*uap->rusage));
878 * wait_args(int pid, int *status, int options, struct rusage *rusage)
881 kern_wait(pid_t pid, int *status, int options, struct rusage *rusage, int *res)
883 struct thread *td = curthread;
885 struct proc *q = td->td_proc;
894 if (options &~ (WUNTRACED|WNOHANG|WCONTINUED|WLINUXCLONE))
898 * Protect the q->p_children list
900 lwkt_gettoken(&q->p_token);
903 * All sorts of things can change due to blocking so we have to loop
904 * all the way back up here.
906 * The problem is that if a process group is stopped and the parent
907 * is doing a wait*(..., WUNTRACED, ...), it will see the STOP
908 * of the child and then stop itself when it tries to return from the
909 * system call. When the process group is resumed the parent will
910 * then get the STOP status even though the child has now resumed
911 * (a followup wait*() will get the CONT status).
913 * Previously the CONT would overwrite the STOP because the tstop
914 * was handled within tsleep(), and the parent would only see
915 * the CONT when both are stopped and continued together. This little
916 * two-line hack restores this effect.
918 while (q->p_stat == SSTOP || q->p_stat == SCORE)
926 * NOTE: We don't want to break q's p_token in the loop for the
927 * case where no children are found or we risk breaking the
928 * interlock between child and parent.
930 waitgen = atomic_fetchadd_long(&q->p_waitgen, 0x80000000);
931 LIST_FOREACH(p, &q->p_children, p_sibling) {
932 if (pid != WAIT_ANY &&
933 p->p_pid != pid && p->p_pgid != -pid) {
938 * This special case handles a kthread spawned by linux_clone
939 * (see linux_misc.c). The linux_wait4 and linux_waitpid
940 * functions need to be able to distinguish between waiting
941 * on a process and waiting on a thread. It is a thread if
942 * p_sigparent is not SIGCHLD, and the WLINUXCLONE option
943 * signifies we want to wait for threads and not processes.
945 if ((p->p_sigparent != SIGCHLD) ^
946 ((options & WLINUXCLONE) != 0)) {
951 if (p->p_stat == SZOMB) {
953 * We may go into SZOMB with threads still present.
954 * We must wait for them to exit before we can reap
955 * the master thread, otherwise we may race reaping
956 * non-master threads.
958 * Only this routine can remove a process from
959 * the zombie list and destroy it, use PACQUIREZOMB()
960 * to serialize us and loop if it blocks (interlocked
961 * by the parent's q->p_token).
963 * WARNING! (p) can be invalid when PHOLDZOMB(p)
964 * returns non-zero. Be sure not to
969 lwkt_gettoken(&p->p_token);
970 if (p->p_pptr != q) {
971 lwkt_reltoken(&p->p_token);
975 while (p->p_nthreads > 0) {
976 tsleep(&p->p_nthreads, 0, "lwpzomb", hz);
980 * Reap any LWPs left in p->p_lwps. This is usually
981 * just the last LWP. This must be done before
982 * we loop on p_lock since the lwps hold a ref on
983 * it as a vmspace interlock.
985 * Once that is accomplished p_nthreads had better
988 while ((lp = RB_ROOT(&p->p_lwp_tree)) != NULL) {
989 lwp_rb_tree_RB_REMOVE(&p->p_lwp_tree, lp);
992 KKASSERT(p->p_nthreads == 0);
995 * Don't do anything really bad until all references
996 * to the process go away. This may include other
997 * LWPs which are still in the process of being
998 * reaped. We can't just pull the rug out from under
999 * them because they may still be using the VM space.
1001 * Certain kernel facilities such as /proc will also
1002 * put a hold on the process for short periods of
1006 PSTALL(p, "reap3", 0);
1008 /* Take care of our return values. */
1012 *status = p->p_xstat;
1017 * If we got the child via a ptrace 'attach',
1018 * we need to give it back to the old parent.
1020 if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
1023 proc_reparent(p, t);
1024 ksignal(t, SIGCHLD);
1028 lwkt_reltoken(&p->p_token);
1034 * Unlink the proc from its process group so that
1035 * the following operations won't lead to an
1036 * inconsistent state for processes running down
1039 proc_remove_zombie(p);
1041 lwkt_reltoken(&p->p_token);
1045 ruadd(&q->p_cru, &p->p_ru);
1048 * Decrement the count of procs running with this uid.
1050 chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
1053 * Free up credentials.
1059 * Remove unused arguments
1063 if (pa && refcount_release(&pa->ar_ref)) {
1069 p->p_sigacts = NULL;
1070 if (ps && refcount_release(&ps->ps_refcnt)) {
1071 kfree(ps, M_SUBPROC);
1076 * Our exitingcount was incremented when the process
1077 * became a zombie, now that the process has been
1078 * removed from (almost) all lists we should be able
1079 * to safely destroy its vmspace. Wait for any current
1080 * holders to go away (so the vmspace remains stable),
1083 PSTALL(p, "reap4", 0);
1084 vmspace_exitfree(p);
1085 PSTALL(p, "reap5", 0);
1088 * NOTE: We have to officially release ZOMB in order
1089 * to ensure that a racing thread in kern_wait()
1090 * which blocked on ZOMB is woken up.
1095 atomic_add_int(&nprocs, -1);
1099 if ((p->p_stat == SSTOP || p->p_stat == SCORE) &&
1100 (p->p_flags & P_WAITED) == 0 &&
1101 ((p->p_flags & P_TRACED) || (options & WUNTRACED))) {
1103 lwkt_gettoken(&p->p_token);
1104 if (p->p_pptr != q) {
1105 lwkt_reltoken(&p->p_token);
1109 if ((p->p_stat != SSTOP && p->p_stat != SCORE) ||
1110 (p->p_flags & P_WAITED) != 0 ||
1111 ((p->p_flags & P_TRACED) == 0 &&
1112 (options & WUNTRACED) == 0)) {
1113 lwkt_reltoken(&p->p_token);
1118 p->p_flags |= P_WAITED;
1122 *status = W_STOPCODE(p->p_xstat);
1123 /* Zero rusage so we get something consistent. */
1125 bzero(rusage, sizeof(*rusage));
1127 lwkt_reltoken(&p->p_token);
1131 if ((options & WCONTINUED) && (p->p_flags & P_CONTINUED)) {
1133 lwkt_gettoken(&p->p_token);
1134 if (p->p_pptr != q) {
1135 lwkt_reltoken(&p->p_token);
1139 if ((p->p_flags & P_CONTINUED) == 0) {
1140 lwkt_reltoken(&p->p_token);
1146 p->p_flags &= ~P_CONTINUED;
1151 lwkt_reltoken(&p->p_token);
1160 if (options & WNOHANG) {
1167 * Wait for signal - interlocked using q->p_waitgen.
1170 while ((waitgen & 0x7FFFFFFF) == (q->p_waitgen & 0x7FFFFFFF)) {
1171 tsleep_interlock(q, PCATCH);
1172 waitgen = atomic_fetchadd_long(&q->p_waitgen, 0x80000000);
1173 if ((waitgen & 0x7FFFFFFF) == (q->p_waitgen & 0x7FFFFFFF)) {
1174 error = tsleep(q, PCATCH | PINTERLOCKED, "wait", 0);
1180 lwkt_reltoken(&q->p_token);
1187 * Change child's parent process to parent.
1189 * p_children/p_sibling requires the parent's token, and
1190 * changing pptr requires the child's token, so we have to
1191 * get three tokens to do this operation. We also need to
1192 * hold pointers that might get ripped out from under us to
1193 * preserve structural integrity.
1195 * It is possible to race another reparent or disconnect or other
1196 * similar operation. We must retry when this situation occurs.
1197 * Once we successfully reparent the process we no longer care
1201 proc_reparent(struct proc *child, struct proc *parent)
1206 while ((opp = child->p_pptr) != parent) {
1208 lwkt_gettoken(&opp->p_token);
1209 lwkt_gettoken(&child->p_token);
1210 lwkt_gettoken(&parent->p_token);
1211 if (child->p_pptr != opp) {
1212 lwkt_reltoken(&parent->p_token);
1213 lwkt_reltoken(&child->p_token);
1214 lwkt_reltoken(&opp->p_token);
1218 LIST_REMOVE(child, p_sibling);
1219 LIST_INSERT_HEAD(&parent->p_children, child, p_sibling);
1220 child->p_pptr = parent;
1221 lwkt_reltoken(&parent->p_token);
1222 lwkt_reltoken(&child->p_token);
1223 lwkt_reltoken(&opp->p_token);
1224 if (LIST_EMPTY(&opp->p_children))
1233 * The next two functions are to handle adding/deleting items on the
1237 * Take the arguments given and put them onto the exit callout list,
1238 * However first make sure that it's not already there.
1239 * returns 0 on success.
1243 at_exit(exitlist_fn function)
1245 struct exitlist *ep;
1248 /* Be noisy if the programmer has lost track of things */
1249 if (rm_at_exit(function))
1250 kprintf("WARNING: exit callout entry (%p) already present\n",
1253 ep = kmalloc(sizeof(*ep), M_ATEXIT, M_NOWAIT);
1256 ep->function = function;
1257 TAILQ_INSERT_TAIL(&exit_list, ep, next);
1262 * Scan the exit callout list for the given item and remove it.
1263 * Returns the number of items removed (0 or 1)
1266 rm_at_exit(exitlist_fn function)
1268 struct exitlist *ep;
1270 TAILQ_FOREACH(ep, &exit_list, next) {
1271 if (ep->function == function) {
1272 TAILQ_REMOVE(&exit_list, ep, next);
1273 kfree(ep, M_ATEXIT);
1281 * LWP reaper related code.
1284 reaplwps(void *context, int dummy)
1286 struct lwplist *lwplist = context;
1290 lwkt_gettoken(&deadlwp_token[cpu]);
1291 while ((lp = LIST_FIRST(lwplist))) {
1292 LIST_REMOVE(lp, u.lwp_reap_entry);
1295 lwkt_reltoken(&deadlwp_token[cpu]);
1299 reaplwp(struct lwp *lp)
1301 while (lwp_wait(lp) == 0)
1311 for (cpu = 0; cpu < ncpus; cpu++) {
1312 lwkt_token_init(&deadlwp_token[cpu], "deadlwpl");
1313 LIST_INIT(&deadlwp_list[cpu]);
1314 deadlwp_task[cpu] = kmalloc(sizeof(*deadlwp_task[cpu]),
1315 M_DEVBUF, M_WAITOK);
1316 TASK_INIT(deadlwp_task[cpu], 0, reaplwps, &deadlwp_list[cpu]);
1320 SYSINIT(deadlwpinit, SI_SUB_CONFIGURE, SI_ORDER_ANY, deadlwp_init, NULL);