Move zombie-reaping code out of kern_wait() and into its own function,
proc_reap(). Reviewed by: jhb MFC after: 3 days Sponsored by: Google, Inc.
This commit is contained in:
Robert Watson
parent
2d316c6d64
commit
324fb6be0f
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=193723
@ -682,11 +682,130 @@ wait4(struct thread *td, struct wait_args *uap)
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return (error);
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}
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/*
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* Reap the remains of a zombie process and optionally return status and
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* rusage. Asserts and will release both the proctree_lock and the process
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* lock as part of its work.
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*/
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static void
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proc_reap(struct thread *td, struct proc *p, int *status, int options,
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struct rusage *rusage)
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{
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INIT_VPROCG(P_TO_VPROCG(p));
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struct proc *q, *t;
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sx_assert(&proctree_lock, SA_XLOCKED);
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PROC_LOCK_ASSERT(p, MA_OWNED);
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PROC_SLOCK_ASSERT(p, MA_OWNED);
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KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
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q = td->td_proc;
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if (rusage) {
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*rusage = p->p_ru;
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calcru(p, &rusage->ru_utime, &rusage->ru_stime);
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}
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PROC_SUNLOCK(p);
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td->td_retval[0] = p->p_pid;
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if (status)
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*status = p->p_xstat; /* convert to int */
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if (options & WNOWAIT) {
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/*
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* Only poll, returning the status. Caller does not wish to
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* release the proc struct just yet.
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*/
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PROC_UNLOCK(p);
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sx_xunlock(&proctree_lock);
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return;
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}
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PROC_LOCK(q);
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sigqueue_take(p->p_ksi);
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PROC_UNLOCK(q);
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PROC_UNLOCK(p);
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/*
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* If we got the child via a ptrace 'attach', we need to give it back
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* to the old parent.
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*/
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if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
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PROC_LOCK(p);
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p->p_oppid = 0;
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proc_reparent(p, t);
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PROC_UNLOCK(p);
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tdsignal(t, NULL, SIGCHLD, p->p_ksi);
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wakeup(t);
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cv_broadcast(&p->p_pwait);
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PROC_UNLOCK(t);
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sx_xunlock(&proctree_lock);
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return;
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}
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/*
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* Remove other references to this process to ensure we have an
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* exclusive reference.
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*/
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sx_xlock(&allproc_lock);
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LIST_REMOVE(p, p_list); /* off zombproc */
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sx_xunlock(&allproc_lock);
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LIST_REMOVE(p, p_sibling);
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leavepgrp(p);
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sx_xunlock(&proctree_lock);
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/*
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* As a side effect of this lock, we know that all other writes to
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* this proc are visible now, so no more locking is needed for p.
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*/
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PROC_LOCK(p);
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p->p_xstat = 0; /* XXX: why? */
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PROC_UNLOCK(p);
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PROC_LOCK(q);
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ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
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PROC_UNLOCK(q);
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/*
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* Decrement the count of procs running with this uid.
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*/
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(void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
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/*
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* Free credentials, arguments, and sigacts.
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*/
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crfree(p->p_ucred);
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p->p_ucred = NULL;
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pargs_drop(p->p_args);
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p->p_args = NULL;
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sigacts_free(p->p_sigacts);
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p->p_sigacts = NULL;
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/*
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* Do any thread-system specific cleanups.
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*/
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thread_wait(p);
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/*
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* Give vm and machine-dependent layer a chance to free anything that
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* cpu_exit couldn't release while still running in process context.
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*/
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vm_waitproc(p);
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#ifdef MAC
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mac_proc_destroy(p);
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#endif
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KASSERT(FIRST_THREAD_IN_PROC(p),
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("proc_reap: no residual thread!"));
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uma_zfree(proc_zone, p);
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sx_xlock(&allproc_lock);
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nprocs--;
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#ifdef VIMAGE
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vprocg->nprocs--;
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#endif
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sx_xunlock(&allproc_lock);
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}
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int
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kern_wait(struct thread *td, pid_t pid, int *status, int options,
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struct rusage *rusage)
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{
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struct proc *p, *q, *t;
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struct proc *p, *q;
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int error, nfound;
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AUDIT_ARG(pid, pid);
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@ -736,111 +855,7 @@ kern_wait(struct thread *td, pid_t pid, int *status, int options,
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nfound++;
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PROC_SLOCK(p);
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if (p->p_state == PRS_ZOMBIE) {
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INIT_VPROCG(P_TO_VPROCG(p));
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if (rusage) {
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*rusage = p->p_ru;
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calcru(p, &rusage->ru_utime, &rusage->ru_stime);
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}
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PROC_SUNLOCK(p);
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td->td_retval[0] = p->p_pid;
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if (status)
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*status = p->p_xstat; /* convert to int */
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if (options & WNOWAIT) {
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/*
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* Only poll, returning the status.
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* Caller does not wish to release the proc
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* struct just yet.
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*/
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PROC_UNLOCK(p);
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sx_xunlock(&proctree_lock);
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return (0);
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}
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PROC_LOCK(q);
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sigqueue_take(p->p_ksi);
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PROC_UNLOCK(q);
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PROC_UNLOCK(p);
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/*
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* If we got the child via a ptrace 'attach',
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* we need to give it back to the old parent.
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*/
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if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
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PROC_LOCK(p);
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p->p_oppid = 0;
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proc_reparent(p, t);
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PROC_UNLOCK(p);
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tdsignal(t, NULL, SIGCHLD, p->p_ksi);
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wakeup(t);
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cv_broadcast(&p->p_pwait);
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PROC_UNLOCK(t);
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sx_xunlock(&proctree_lock);
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return (0);
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}
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/*
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* Remove other references to this process to ensure
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* we have an exclusive reference.
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*/
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sx_xlock(&allproc_lock);
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LIST_REMOVE(p, p_list); /* off zombproc */
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sx_xunlock(&allproc_lock);
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LIST_REMOVE(p, p_sibling);
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leavepgrp(p);
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sx_xunlock(&proctree_lock);
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/*
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* As a side effect of this lock, we know that
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* all other writes to this proc are visible now, so
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* no more locking is needed for p.
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*/
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PROC_LOCK(p);
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p->p_xstat = 0; /* XXX: why? */
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PROC_UNLOCK(p);
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PROC_LOCK(q);
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ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru,
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&p->p_rux);
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PROC_UNLOCK(q);
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/*
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* Decrement the count of procs running with this uid.
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*/
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(void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
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/*
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* Free credentials, arguments, and sigacts.
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*/
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crfree(p->p_ucred);
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p->p_ucred = NULL;
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pargs_drop(p->p_args);
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p->p_args = NULL;
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sigacts_free(p->p_sigacts);
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p->p_sigacts = NULL;
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/*
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* Do any thread-system specific cleanups.
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*/
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thread_wait(p);
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/*
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* Give vm and machine-dependent layer a chance
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* to free anything that cpu_exit couldn't
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* release while still running in process context.
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*/
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vm_waitproc(p);
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#ifdef MAC
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mac_proc_destroy(p);
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#endif
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KASSERT(FIRST_THREAD_IN_PROC(p),
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("kern_wait: no residual thread!"));
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uma_zfree(proc_zone, p);
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sx_xlock(&allproc_lock);
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nprocs--;
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#ifdef VIMAGE
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vprocg->nprocs--;
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#endif
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sx_xunlock(&allproc_lock);
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proc_reap(td, p, status, options, rusage);
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return (0);
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}
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if ((p->p_flag & P_STOPPED_SIG) &&
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