bsd/kern/kern_fork.c

   1 /*
   2  * Copyright (c) 2000-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
  23 /*
  24  * Copyright (c) 1982, 1986, 1989, 1991, 1993
  25  *      The Regents of the University of California.  All rights reserved.
  26  * (c) UNIX System Laboratories, Inc.
  27  * All or some portions of this file are derived from material licensed
  28  * to the University of California by American Telephone and Telegraph
  29  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
  30  * the permission of UNIX System Laboratories, Inc.
  31  *
  32  * Redistribution and use in source and binary forms, with or without
  33  * modification, are permitted provided that the following conditions
  34  * are met:
  35  * 1. Redistributions of source code must retain the above copyright
  36  *    notice, this list of conditions and the following disclaimer.
  37  * 2. Redistributions in binary form must reproduce the above copyright
  38  *    notice, this list of conditions and the following disclaimer in the
  39  *    documentation and/or other materials provided with the distribution.
  40  * 3. All advertising materials mentioning features or use of this software
  41  *    must display the following acknowledgement:
  42  *      This product includes software developed by the University of
  43  *      California, Berkeley and its contributors.
  44  * 4. Neither the name of the University nor the names of its contributors
  45  *    may be used to endorse or promote products derived from this software
  46  *    without specific prior written permission.
  47  *
  48  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  49  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  50  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  51  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  52  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  53  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  54  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  55  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  56  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  57  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  58  * SUCH DAMAGE.
  59  *
  60  *      @(#)kern_fork.c 8.8 (Berkeley) 2/14/95
  61  */
  62
  63 #include <sys/param.h>
  64 #include <sys/systm.h>
  65 #include <sys/filedesc.h>
  66 #include <sys/kernel.h>
  67 #include <sys/malloc.h>
  68 #include <sys/proc.h>
  69 #include <sys/user.h>
  70 #include <sys/resourcevar.h>
  71 #include <sys/vnode.h>
  72 #include <sys/file.h>
  73 #include <sys/acct.h>
  74 #if KTRACE
  75 #include <sys/ktrace.h>
  76 #endif
  77
  78 #include <mach/mach_types.h>
  79 #include <kern/mach_param.h>
  80
  81 #include <machine/spl.h>
  82
  83 thread_act_t cloneproc(struct proc *, int);
  84 struct proc * forkproc(struct proc *, int);
  85 thread_act_t procdup();
  86
  87 #define DOFORK  0x1     /* fork() system call */
  88 #define DOVFORK 0x2     /* vfork() system call */
  89 static int fork1(struct proc *, long, register_t *);
  90
  91 /*
  92  * fork system call.
  93  */
  94 int
  95 fork(p, uap, retval)
  96         struct proc *p;
  97         void *uap;
  98         register_t *retval;
  99 {
 100         return (fork1(p, (long)DOFORK, retval));
 101 }
 102
 103 /*
 104  * vfork system call
 105  */
 106 int
 107 vfork(p, uap, retval)
 108         struct proc *p;
 109         void *uap;
 110         register_t *retval;
 111 {
 112         register struct proc * newproc;
 113         register uid_t uid;
 114         thread_act_t cur_act = (thread_act_t)current_act();
 115         int count;
 116         task_t t;
 117         uthread_t ut;
 118
 119         /*
 120          * Although process entries are dynamically created, we still keep
 121          * a global limit on the maximum number we will create.  Don't allow
 122          * a nonprivileged user to use the last process; don't let root
 123          * exceed the limit. The variable nprocs is the current number of
 124          * processes, maxproc is the limit.
 125          */
 126         uid = p->p_cred->p_ruid;
 127         if ((nprocs >= maxproc - 1 && uid != 0) || nprocs >= maxproc) {
 128                 tablefull("proc");
 129                 retval[1] = 0;
 130                 return (EAGAIN);
 131         }
 132
 133         /*
 134          * Increment the count of procs running with this uid. Don't allow
 135          * a nonprivileged user to exceed their current limit.
 136          */
 137         count = chgproccnt(uid, 1);
 138         if (uid != 0 && count > p->p_rlimit[RLIMIT_NPROC].rlim_cur) {
 139                 (void)chgproccnt(uid, -1);
 140                 return (EAGAIN);
 141         }
 142
 143         ut = (struct uthread *)get_bsdthread_info(cur_act);
 144         if (ut->uu_flag & P_VFORK) {
 145                 printf("vfork called recursively by %s\n", p->p_comm);
 146                 return (EINVAL);
 147         }
 148         p->p_flag  |= P_VFORK;
 149         p->p_vforkcnt++;
 150
 151         /* The newly created process comes with signal lock held */
 152         newproc = (struct proc *)forkproc(p,1);
 153
 154         LIST_INSERT_AFTER(p, newproc, p_pglist);
 155         newproc->p_pptr = p;
 156         newproc->task = p->task;
 157         LIST_INSERT_HEAD(&p->p_children, newproc, p_sibling);
 158         LIST_INIT(&newproc->p_children);
 159         LIST_INSERT_HEAD(&allproc, newproc, p_list);
 160         LIST_INSERT_HEAD(PIDHASH(newproc->p_pid), newproc, p_hash);
 161         TAILQ_INIT(& newproc->p_evlist);
 162         newproc->p_stat = SRUN;
 163         newproc->p_flag  |= P_INVFORK;
 164         newproc->p_vforkact = cur_act;
 165
 166         ut->uu_flag |= P_VFORK;
 167         ut->uu_proc = newproc;
 168         ut->uu_userstate = (void *)act_thread_csave();
 169         ut->uu_vforkmask = ut->uu_sigmask;
 170
 171         thread_set_child(cur_act, newproc->p_pid);
 172
 173         newproc->p_stats->p_start = time;
 174         newproc->p_acflag = AFORK;
 175
 176         /*
 177          * Preserve synchronization semantics of vfork.  If waiting for
 178          * child to exec or exit, set P_PPWAIT on child, and sleep on our
 179          * proc (in case of exit).
 180          */
 181         newproc->p_flag |= P_PPWAIT;
 182
 183         /* drop the signal lock on the child */
 184         signal_unlock(newproc);
 185
 186         retval[0] = newproc->p_pid;
 187         retval[1] = 1;                  /* mark child */
 188
 189         return (0);
 190 }
 191
 192 /*
 193  * Return to parent vfork ehread()
 194  */
 195 void
 196 vfork_return(th_act, p, p2, retval)
 197         thread_act_t th_act;
 198         struct proc * p;
 199         struct proc *p2;
 200         register_t *retval;
 201 {
 202         long flags;
 203         register uid_t uid;
 204         thread_t newth, self = current_thread();
 205         thread_act_t cur_act = (thread_act_t)current_act();
 206         int s, count;
 207         task_t t;
 208         uthread_t ut;
 209
 210         ut = (struct uthread *)get_bsdthread_info(cur_act);
 211
 212         act_thread_catt(ut->uu_userstate);
 213
 214         /* Make sure only one at this time */
 215         p->p_vforkcnt--;
 216         if (p->p_vforkcnt <0)
 217                 panic("vfork cnt is -ve");
 218         if (p->p_vforkcnt <=0)
 219                 p->p_flag  &= ~P_VFORK;
 220         ut->uu_userstate = 0;
 221         ut->uu_flag &= ~P_VFORK;
 222         ut->uu_proc = 0;
 223         ut->uu_sigmask = ut->uu_vforkmask;
 224         p2->p_flag  &= ~P_INVFORK;
 225         p2->p_vforkact = (void *)0;
 226
 227         thread_set_parent(cur_act, p2->p_pid);
 228
 229         if (retval) {
 230                 retval[0] = p2->p_pid;
 231                 retval[1] = 0;                  /* mark parent */
 232         }
 233
 234         return;
 235 }
 236
 237 thread_act_t
 238 procdup(
 239         struct proc             *child,
 240         struct proc             *parent)
 241 {
 242         thread_act_t            thread;
 243         task_t                  task;
 244         kern_return_t   result;
 245         extern task_t kernel_task;
 246
 247         if (parent->task == kernel_task)
 248                 result = task_create_local(TASK_NULL, FALSE, FALSE, &task);
 249         else
 250                 result = task_create_local(parent->task, TRUE, FALSE, &task);
 251         if (result != KERN_SUCCESS)
 252             printf("fork/procdup: task_create failed. Code: 0x%x\n", result);
 253         child->task = task;
 254         /* task->proc = child; */
 255         set_bsdtask_info(task, child);
 256         if (child->p_nice != 0)
 257                 resetpriority(child);
 258         result = thread_create(task, &thread);
 259         if (result != KERN_SUCCESS)
 260             printf("fork/procdup: thread_create failed. Code: 0x%x\n", result);
 261
 262         return(thread);
 263 }
 264
 265
 266 static int
 267 fork1(p1, flags, retval)
 268         struct proc *p1;
 269         long flags;
 270         register_t *retval;
 271 {
 272         register struct proc *p2;
 273         register uid_t uid;
 274         thread_act_t newth;
 275         int s, count;
 276         task_t t;
 277
 278         /*
 279          * Although process entries are dynamically created, we still keep
 280          * a global limit on the maximum number we will create.  Don't allow
 281          * a nonprivileged user to use the last process; don't let root
 282          * exceed the limit. The variable nprocs is the current number of
 283          * processes, maxproc is the limit.
 284          */
 285         uid = p1->p_cred->p_ruid;
 286         if ((nprocs >= maxproc - 1 && uid != 0) || nprocs >= maxproc) {
 287                 tablefull("proc");
 288                 retval[1] = 0;
 289                 return (EAGAIN);
 290         }
 291
 292         /*
 293          * Increment the count of procs running with this uid. Don't allow
 294          * a nonprivileged user to exceed their current limit.
 295          */
 296         count = chgproccnt(uid, 1);
 297         if (uid != 0 && count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur) {
 298                 (void)chgproccnt(uid, -1);
 299                 return (EAGAIN);
 300         }
 301
 302         /* The newly created process comes with signal lock held */
 303         newth = cloneproc(p1, 1);
 304         thread_dup(newth);
 305         /* p2 = newth->task->proc; */
 306         p2 = (struct proc *)(get_bsdtask_info(get_threadtask(newth)));
 307
 308         thread_set_child(newth, p2->p_pid);
 309
 310         s = splhigh();
 311         p2->p_stats->p_start = time;
 312         splx(s);
 313         p2->p_acflag = AFORK;
 314
 315         /*
 316          * Preserve synchronization semantics of vfork.  If waiting for
 317          * child to exec or exit, set P_PPWAIT on child, and sleep on our
 318          * proc (in case of exit).
 319          */
 320         if (flags == DOVFORK)
 321                 p2->p_flag |= P_PPWAIT;
 322         /* drop the signal lock on the child */
 323         signal_unlock(p2);
 324
 325         (void) thread_resume(newth);
 326
 327         /* drop the extra references we got during the creation */
 328         if (t = (task_t)get_threadtask(newth)) {
 329                 task_deallocate(t);
 330         }
 331         act_deallocate(newth);
 332
 333         while (p2->p_flag & P_PPWAIT)
 334                 tsleep(p1, PWAIT, "ppwait", 0);
 335
 336         retval[0] = p2->p_pid;
 337         retval[1] = 0;                  /* mark parent */
 338
 339         return (0);
 340 }
 341
 342 /*
 343  * cloneproc()
 344  *
 345  * Create a new process from a specified process.
 346  * On return newly created child process has signal
 347  * lock held to block delivery of signal to it if called with
 348  * lock set. fork() code needs to explicity remove this lock
 349  * before signals can be delivered
 350  */
 351 thread_act_t
 352 cloneproc(p1, lock)
 353         register struct proc *p1;
 354         register int lock;
 355 {
 356         register struct proc *p2;
 357         thread_act_t th;
 358
 359         p2 = (struct proc *)forkproc(p1,lock);
 360
 361
 362         th = procdup(p2, p1);   /* child, parent */
 363
 364         LIST_INSERT_AFTER(p1, p2, p_pglist);
 365         p2->p_pptr = p1;
 366         LIST_INSERT_HEAD(&p1->p_children, p2, p_sibling);
 367         LIST_INIT(&p2->p_children);
 368         LIST_INSERT_HEAD(&allproc, p2, p_list);
 369         LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash);
 370         TAILQ_INIT(&p2->p_evlist);
 371         /*
 372          * Make child runnable, set start time.
 373          */
 374         p2->p_stat = SRUN;
 375
 376         return(th);
 377 }
 378
 379 struct proc *
 380 forkproc(p1, lock)
 381         register struct proc *p1;
 382         register int lock;
 383 {
 384         register struct proc *p2, *newproc;
 385         static int nextpid = 0, pidchecked = 0;
 386         thread_t th;
 387
 388         /* Allocate new proc. */
 389         MALLOC_ZONE(newproc, struct proc *,
 390                         sizeof *newproc, M_PROC, M_WAITOK);
 391         MALLOC_ZONE(newproc->p_cred, struct pcred *,
 392                         sizeof *newproc->p_cred, M_SUBPROC, M_WAITOK);
 393         MALLOC_ZONE(newproc->p_stats, struct pstats *,
 394                         sizeof *newproc->p_stats, M_SUBPROC, M_WAITOK);
 395         MALLOC_ZONE(newproc->p_sigacts, struct sigacts *,
 396                         sizeof *newproc->p_sigacts, M_SUBPROC, M_WAITOK);
 397
 398         /*
 399          * Find an unused process ID.  We remember a range of unused IDs
 400          * ready to use (from nextpid+1 through pidchecked-1).
 401          */
 402         nextpid++;
 403 retry:
 404         /*
 405          * If the process ID prototype has wrapped around,
 406          * restart somewhat above 0, as the low-numbered procs
 407          * tend to include daemons that don't exit.
 408          */
 409         if (nextpid >= PID_MAX) {
 410                 nextpid = 100;
 411                 pidchecked = 0;
 412         }
 413         if (nextpid >= pidchecked) {
 414                 int doingzomb = 0;
 415
 416                 pidchecked = PID_MAX;
 417                 /*
 418                  * Scan the active and zombie procs to check whether this pid
 419                  * is in use.  Remember the lowest pid that's greater
 420                  * than nextpid, so we can avoid checking for a while.
 421                  */
 422                 p2 = allproc.lh_first;
 423 again:
 424                 for (; p2 != 0; p2 = p2->p_list.le_next) {
 425                         while (p2->p_pid == nextpid ||
 426                             p2->p_pgrp->pg_id == nextpid ||
 427                                 p2->p_session->s_sid == nextpid) {
 428                                 nextpid++;
 429                                 if (nextpid >= pidchecked)
 430                                         goto retry;
 431                         }
 432                         if (p2->p_pid > nextpid && pidchecked > p2->p_pid)
 433                                 pidchecked = p2->p_pid;
 434                         if (p2->p_pgrp && p2->p_pgrp->pg_id > nextpid &&
 435                             pidchecked > p2->p_pgrp->pg_id)
 436                                 pidchecked = p2->p_pgrp->pg_id;
 437                         if (p2->p_session->s_sid > nextpid &&
 438                                 pidchecked > p2->p_session->s_sid)
 439                                 pidchecked = p2->p_session->s_sid;
 440                 }
 441                 if (!doingzomb) {
 442                         doingzomb = 1;
 443                         p2 = zombproc.lh_first;
 444                         goto again;
 445                 }
 446         }
 447
 448         nprocs++;
 449         p2 = newproc;
 450         p2->p_stat = SIDL;
 451         p2->p_pid = nextpid;
 452
 453         /*
 454          * Make a proc table entry for the new process.
 455          * Start by zeroing the section of proc that is zero-initialized,
 456          * then copy the section that is copied directly from the parent.
 457          */
 458         bzero(&p2->p_startzero,
 459             (unsigned) ((caddr_t)&p2->p_endzero - (caddr_t)&p2->p_startzero));
 460         bcopy(&p1->p_startcopy, &p2->p_startcopy,
 461             (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy));
 462         p2->vm_shm = (void *)NULL; /* Make sure it is zero */
 463
 464         /*
 465          * Duplicate sub-structures as needed.
 466          * Increase reference counts on shared objects.
 467          * The p_stats and p_sigacts substructs are set in vm_fork.
 468          */
 469         p2->p_flag = P_INMEM;
 470         if (p1->p_flag & P_PROFIL)
 471                 startprofclock(p2);
 472         bcopy(p1->p_cred, p2->p_cred, sizeof(*p2->p_cred));
 473         p2->p_cred->p_refcnt = 1;
 474         crhold(p1->p_ucred);
 475         lockinit(&p2->p_cred->pc_lock, PLOCK, "proc cred", 0, 0);
 476
 477         /* bump references to the text vnode */
 478         p2->p_textvp = p1->p_textvp;
 479         if (p2->p_textvp)
 480                 VREF(p2->p_textvp);
 481
 482         p2->p_fd = fdcopy(p1);
 483         if (p1->vm_shm) {
 484                 shmfork(p1,p2);
 485         }
 486         /*
 487          * If p_limit is still copy-on-write, bump refcnt,
 488          * otherwise get a copy that won't be modified.
 489          * (If PL_SHAREMOD is clear, the structure is shared
 490          * copy-on-write.)
 491          */
 492         if (p1->p_limit->p_lflags & PL_SHAREMOD)
 493                 p2->p_limit = limcopy(p1->p_limit);
 494         else {
 495                 p2->p_limit = p1->p_limit;
 496                 p2->p_limit->p_refcnt++;
 497         }
 498
 499         bzero(&p2->p_stats->pstat_startzero,
 500             (unsigned) ((caddr_t)&p2->p_stats->pstat_endzero -
 501             (caddr_t)&p2->p_stats->pstat_startzero));
 502         bcopy(&p1->p_stats->pstat_startcopy, &p2->p_stats->pstat_startcopy,
 503             ((caddr_t)&p2->p_stats->pstat_endcopy -
 504              (caddr_t)&p2->p_stats->pstat_startcopy));
 505
 506         if (p1->p_sigacts != NULL)
 507                 (void)memcpy(p2->p_sigacts,
 508                                 p1->p_sigacts, sizeof *p2->p_sigacts);
 509         else
 510                 (void)memset(p2->p_sigacts, 0, sizeof *p2->p_sigacts);
 511
 512         if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT)
 513                 p2->p_flag |= P_CONTROLT;
 514
 515         p2->p_xstat = 0;
 516         p2->p_ru = NULL;
 517
 518         p2->p_debugger = 0;     /* don't inherit */
 519         lockinit(&p2->signal_lock, PVM, "signal", 0, 0);
 520         /* block all signals to reach the process */
 521         if (lock)
 522                 signal_lock(p2);
 523         p2->sigwait = FALSE;
 524         p2->sigwait_thread = NULL;
 525         p2->exit_thread = NULL;
 526         p2->user_stack = p1->user_stack;
 527         p2->p_xxxsigpending = 0;
 528         p2->p_vforkcnt = 0;
 529         p2->p_vforkact = 0;
 530         TAILQ_INIT(&p2->p_uthlist);
 531
 532 #if KTRACE
 533         /*
 534          * Copy traceflag and tracefile if enabled.
 535          * If not inherited, these were zeroed above.
 536          */
 537         if (p1->p_traceflag&KTRFAC_INHERIT) {
 538                 p2->p_traceflag = p1->p_traceflag;
 539                 if ((p2->p_tracep = p1->p_tracep) != NULL)
 540                         VREF(p2->p_tracep);
 541         }
 542 #endif
 543         return(p2);
 544
 545 }
 546
 547 #include <kern/zalloc.h>
 548
 549 struct zone     *uthread_zone;
 550 int uthread_zone_inited = 0;
 551
 552 void
 553 uthread_zone_init()
 554 {
 555         if (!uthread_zone_inited) {
 556                 uthread_zone = zinit(sizeof(struct uthread),
 557                                                         THREAD_MAX * sizeof(struct uthread),
 558                                                         THREAD_CHUNK * sizeof(struct uthread),
 559                                                         "uthreads");
 560                 uthread_zone_inited = 1;
 561         }
 562 }
 563
 564 void *
 565 uthread_alloc(task_t task, thread_act_t thr_act )
 566 {
 567         struct proc *p;
 568         struct uthread *uth, *uth_parent;
 569         void *ut;
 570         extern task_t kernel_task;
 571         boolean_t funnel_state;
 572
 573         if (!uthread_zone_inited)
 574                 uthread_zone_init();
 575
 576         ut = (void *)zalloc(uthread_zone);
 577         bzero(ut, sizeof(struct uthread));
 578
 579         if (task != kernel_task) {
 580                 uth = (struct uthread *)ut;
 581                 p = get_bsdtask_info(task);
 582
 583                 funnel_state = thread_funnel_set(kernel_flock, TRUE);
 584                 uth_parent = (struct uthread *)get_bsdthread_info(current_act());
 585                 if (uth_parent) {
 586                         if (uth_parent->uu_flag & USAS_OLDMASK)
 587                                 uth->uu_sigmask = uth_parent->uu_oldmask;
 588                         else
 589                                 uth->uu_sigmask = uth_parent->uu_sigmask;
 590                 }
 591                 uth->uu_act = thr_act;
 592                 //signal_lock(p);
 593                 if (p)
 594                         TAILQ_INSERT_TAIL(&p->p_uthlist, uth, uu_list);
 595                 //signal_unlock(p);
 596                 (void)thread_funnel_set(kernel_flock, funnel_state);
 597         }
 598
 599         return (ut);
 600 }
 601
 602
 603 void
 604 uthread_free(task_t task, void *uthread, void * bsd_info)
 605 {
 606         struct _select *sel;
 607         struct uthread *uth = (struct uthread *)uthread;
 608         struct proc * p = (struct proc *)bsd_info;
 609         extern task_t kernel_task;
 610         int size;
 611         boolean_t funnel_state;
 612
 613         sel = &uth->uu_state.ss_select;
 614         /* cleanup the select bit space */
 615         if (sel->nbytes) {
 616                 FREE(sel->ibits, M_TEMP);
 617                 FREE(sel->obits, M_TEMP);
 618         }
 619
 620         if (sel->allocsize && uth->uu_wqsub){
 621                 kfree(uth->uu_wqsub, sel->allocsize);
 622                 sel->count = sel->nfcount = 0;
 623                 sel->allocsize = 0;
 624                 uth->uu_wqsub = 0;
 625                 sel->wql = 0;
 626         }
 627
 628         if ((task != kernel_task) && p) {
 629                 funnel_state = thread_funnel_set(kernel_flock, TRUE);
 630                 //signal_lock(p);
 631                 TAILQ_REMOVE(&p->p_uthlist, uth, uu_list);
 632                 //signal_unlock(p);
 633                 (void)thread_funnel_set(kernel_flock, funnel_state);
 634         }
 635         /* and free the uthread itself */
 636         zfree(uthread_zone, (vm_offset_t)uthread);
 637 }