sys/kern/kern_shutdown.c

   1 /*-
   2  * Copyright (c) 1986, 1988, 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * (c) UNIX System Laboratories, Inc.
   5  * All or some portions of this file are derived from material licensed
   6  * to the University of California by American Telephone and Telegraph
   7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   8  * the permission of UNIX System Laboratories, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *      This product includes software developed by the University of
  21  *      California, Berkeley and its contributors.
  22  * 4. Neither the name of the University nor the names of its contributors
  23  *    may be used to endorse or promote products derived from this software
  24  *    without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  *      @(#)kern_shutdown.c     8.3 (Berkeley) 1/21/94
  39  * $FreeBSD: src/sys/kern/kern_shutdown.c,v 1.72.2.12 2002/02/21 19:15:10 dillon Exp $
  40  * $DragonFly: src/sys/kern/kern_shutdown.c,v 1.19 2005/04/19 17:54:42 dillon Exp $
  41  */
  42
  43 #include "opt_ddb.h"
  44 #include "opt_ddb_trace.h"
  45 #include "opt_hw_wdog.h"
  46 #include "opt_panic.h"
  47 #include "opt_show_busybufs.h"
  48
  49 #include <sys/param.h>
  50 #include <sys/systm.h>
  51 #include <sys/eventhandler.h>
  52 #include <sys/buf.h>
  53 #include <sys/disklabel.h>
  54 #include <sys/reboot.h>
  55 #include <sys/proc.h>
  56 #include <sys/vnode.h>
  57 #include <sys/kernel.h>
  58 #include <sys/kthread.h>
  59 #include <sys/malloc.h>
  60 #include <sys/mount.h>
  61 #include <sys/queue.h>
  62 #include <sys/sysctl.h>
  63 #include <sys/conf.h>
  64 #include <sys/sysproto.h>
  65 #include <sys/device.h>
  66 #include <sys/cons.h>
  67 #include <sys/buf2.h>
  68
  69 #include <machine/pcb.h>
  70 #include <machine/clock.h>
  71 #include <machine/md_var.h>
  72 #include <machine/smp.h>                /* smp_active_mask, cpuid */
  73
  74 #include <sys/signalvar.h>
  75
  76 #ifndef PANIC_REBOOT_WAIT_TIME
  77 #define PANIC_REBOOT_WAIT_TIME 15 /* default to 15 seconds */
  78 #endif
  79
  80 /*
  81  * Note that stdarg.h and the ANSI style va_start macro is used for both
  82  * ANSI and traditional C compilers.  We use the machine version to stay
  83  * within the confines of the kernel header files.
  84  */
  85 #include <machine/stdarg.h>
  86
  87 #ifdef DDB
  88 #ifdef DDB_UNATTENDED
  89 int debugger_on_panic = 0;
  90 #else
  91 int debugger_on_panic = 1;
  92 #endif
  93 SYSCTL_INT(_debug, OID_AUTO, debugger_on_panic, CTLFLAG_RW,
  94         &debugger_on_panic, 0, "Run debugger on kernel panic");
  95
  96 extern void db_print_backtrace(void);
  97
  98 #ifdef DDB_TRACE
  99 int trace_on_panic = 1;
 100 #else
 101 int trace_on_panic = 0;
 102 #endif
 103 SYSCTL_INT(_debug, OID_AUTO, trace_on_panic, CTLFLAG_RW,
 104         &trace_on_panic, 0, "Print stack trace on kernel panic");
 105 #endif
 106
 107 static int sync_on_panic = 1;
 108 SYSCTL_INT(_kern, OID_AUTO, sync_on_panic, CTLFLAG_RW,
 109         &sync_on_panic, 0, "Do a sync before rebooting from a panic");
 110
 111 SYSCTL_NODE(_kern, OID_AUTO, shutdown, CTLFLAG_RW, 0, "Shutdown environment");
 112
 113 #ifdef  HW_WDOG
 114 /*
 115  * If there is a hardware watchdog, point this at the function needed to
 116  * hold it off.
 117  * It's needed when the kernel needs to do some lengthy operations.
 118  * e.g. in wd.c when dumping core.. It's most annoying to have
 119  * your precious core-dump only half written because the wdog kicked in.
 120  */
 121 watchdog_tickle_fn wdog_tickler = NULL;
 122 #endif  /* HW_WDOG */
 123
 124 /*
 125  * Variable panicstr contains argument to first call to panic; used as flag
 126  * to indicate that the kernel has already called panic.
 127  */
 128 const char *panicstr;
 129
 130 int dumping;                            /* system is dumping */
 131
 132 static void boot (int) __dead2;
 133 static void dumpsys (void);
 134 static int setdumpdev (dev_t dev);
 135 static void poweroff_wait (void *, int);
 136 static void print_uptime (void);
 137 static void shutdown_halt (void *junk, int howto);
 138 static void shutdown_panic (void *junk, int howto);
 139 static void shutdown_reset (void *junk, int howto);
 140
 141 /* register various local shutdown events */
 142 static void
 143 shutdown_conf(void *unused)
 144 {
 145         EVENTHANDLER_REGISTER(shutdown_final, poweroff_wait, NULL, SHUTDOWN_PRI_FIRST);
 146         EVENTHANDLER_REGISTER(shutdown_final, shutdown_halt, NULL, SHUTDOWN_PRI_LAST + 100);
 147         EVENTHANDLER_REGISTER(shutdown_final, shutdown_panic, NULL, SHUTDOWN_PRI_LAST + 100);
 148         EVENTHANDLER_REGISTER(shutdown_final, shutdown_reset, NULL, SHUTDOWN_PRI_LAST + 200);
 149 }
 150
 151 SYSINIT(shutdown_conf, SI_SUB_INTRINSIC, SI_ORDER_ANY, shutdown_conf, NULL)
 152
 153 /* ARGSUSED */
 154
 155 /*
 156  * The system call that results in a reboot
 157  */
 158 int
 159 reboot(struct reboot_args *uap)
 160 {
 161         struct thread *td = curthread;
 162         int error;
 163
 164         if ((error = suser(td)))
 165                 return (error);
 166
 167         boot(uap->opt);
 168         return (0);
 169 }
 170
 171 /*
 172  * Called by events that want to shut down.. e.g  <CTL><ALT><DEL> on a PC
 173  */
 174 static int shutdown_howto = 0;
 175
 176 void
 177 shutdown_nice(int howto)
 178 {
 179         shutdown_howto = howto;
 180
 181         /* Send a signal to init(8) and have it shutdown the world */
 182         if (initproc != NULL) {
 183                 psignal(initproc, SIGINT);
 184         } else {
 185                 /* No init(8) running, so simply reboot */
 186                 boot(RB_NOSYNC);
 187         }
 188         return;
 189 }
 190 static int      waittime = -1;
 191 static struct pcb dumppcb;
 192
 193 static void
 194 print_uptime()
 195 {
 196         int f;
 197         struct timespec ts;
 198
 199         getnanouptime(&ts);
 200         printf("Uptime: ");
 201         f = 0;
 202         if (ts.tv_sec >= 86400) {
 203                 printf("%ldd", ts.tv_sec / 86400);
 204                 ts.tv_sec %= 86400;
 205                 f = 1;
 206         }
 207         if (f || ts.tv_sec >= 3600) {
 208                 printf("%ldh", ts.tv_sec / 3600);
 209                 ts.tv_sec %= 3600;
 210                 f = 1;
 211         }
 212         if (f || ts.tv_sec >= 60) {
 213                 printf("%ldm", ts.tv_sec / 60);
 214                 ts.tv_sec %= 60;
 215                 f = 1;
 216         }
 217         printf("%lds\n", ts.tv_sec);
 218 }
 219
 220 /*
 221  *  Go through the rigmarole of shutting down..
 222  * this used to be in machdep.c but I'll be dammned if I could see
 223  * anything machine dependant in it.
 224  */
 225 static void
 226 boot(int howto)
 227 {
 228
 229         /* collect extra flags that shutdown_nice might have set */
 230         howto |= shutdown_howto;
 231
 232 #ifdef SMP
 233         if (smp_active_mask > 1) {
 234                 printf("boot() called on cpu#%d\n", mycpu->gd_cpuid);
 235         }
 236 #endif
 237         /*
 238          * Do any callouts that should be done BEFORE syncing the filesystems.
 239          */
 240         EVENTHANDLER_INVOKE(shutdown_pre_sync, howto);
 241
 242         /*
 243          * Now sync filesystems
 244          */
 245         if (!cold && (howto & RB_NOSYNC) == 0 && waittime < 0) {
 246                 struct buf *bp;
 247                 int iter, nbusy, pbusy;
 248
 249                 waittime = 0;
 250                 printf("\nsyncing disks... ");
 251
 252                 sync(NULL);     /* YYY was sync(&proc0, NULL). why proc0 ? */
 253
 254                 /*
 255                  * With soft updates, some buffers that are
 256                  * written will be remarked as dirty until other
 257                  * buffers are written.
 258                  */
 259                 for (iter = pbusy = 0; iter < 20; iter++) {
 260                         nbusy = 0;
 261                         for (bp = &buf[nbuf]; --bp >= buf; ) {
 262                                 if ((bp->b_flags & B_INVAL) == 0 &&
 263                                     BUF_REFCNT(bp) > 0) {
 264                                         nbusy++;
 265                                 } else if ((bp->b_flags & (B_DELWRI | B_INVAL))
 266                                                 == B_DELWRI) {
 267                                         /* bawrite(bp);*/
 268                                         nbusy++;
 269                                 }
 270                         }
 271                         if (nbusy == 0)
 272                                 break;
 273                         printf("%d ", nbusy);
 274                         if (nbusy < pbusy)
 275                                 iter = 0;
 276                         pbusy = nbusy;
 277                         /*
 278                          * XXX:
 279                          * Process soft update work queue if buffers don't sync
 280                          * after 6 iterations by permitting the syncer to run.
 281                          */
 282                         if (iter > 5 && bioops.io_sync)
 283                                 (*bioops.io_sync)(NULL);
 284                         sync(NULL); /* YYY was sync(&proc0, NULL). why proc0 ? */
 285                         DELAY(50000 * iter);
 286                 }
 287                 printf("\n");
 288                 /*
 289                  * Count only busy local buffers to prevent forcing
 290                  * a fsck if we're just a client of a wedged NFS server
 291                  */
 292                 nbusy = 0;
 293                 for (bp = &buf[nbuf]; --bp >= buf; ) {
 294                         if (((bp->b_flags&B_INVAL) == 0 && BUF_REFCNT(bp)) ||
 295                             ((bp->b_flags & (B_DELWRI|B_INVAL)) == B_DELWRI)) {
 296                                 if (bp->b_dev == NODEV) {
 297                                         mountlist_remove(bp->b_vp->v_mount);
 298                                         continue;
 299                                 }
 300                                 nbusy++;
 301 #if defined(SHOW_BUSYBUFS) || defined(DIAGNOSTIC)
 302                                 printf(
 303                             "%p %d: dev:%s, flags:%08lx, blkno:%ld, lblkno:%ld\n",
 304                                     bp, nbusy, devtoname(bp->b_dev),
 305                                     bp->b_flags, (long)bp->b_blkno,
 306                                     (long)bp->b_lblkno);
 307 #endif
 308                         }
 309                 }
 310                 if (nbusy) {
 311                         /*
 312                          * Failed to sync all blocks. Indicate this and don't
 313                          * unmount filesystems (thus forcing an fsck on reboot).
 314                          */
 315                         printf("giving up on %d buffers\n", nbusy);
 316 #ifdef DDB
 317                         Debugger("busy buffer problem");
 318 #endif /* DDB */
 319                         DELAY(5000000); /* 5 seconds */
 320                 } else {
 321                         printf("done\n");
 322                         /*
 323                          * Unmount filesystems
 324                          */
 325                         if (panicstr == 0)
 326                                 vfs_unmountall();
 327                 }
 328                 DELAY(100000);          /* wait for console output to finish */
 329         }
 330
 331         print_uptime();
 332
 333         /*
 334          * Ok, now do things that assume all filesystem activity has
 335          * been completed.
 336          */
 337         EVENTHANDLER_INVOKE(shutdown_post_sync, howto);
 338         splhigh();
 339         if ((howto & (RB_HALT|RB_DUMP)) == RB_DUMP && !cold)
 340                 dumpsys();
 341
 342         /* Now that we're going to really halt the system... */
 343         EVENTHANDLER_INVOKE(shutdown_final, howto);
 344
 345         for(;;) ;       /* safety against shutdown_reset not working */
 346         /* NOTREACHED */
 347 }
 348
 349 /*
 350  * If the shutdown was a clean halt, behave accordingly.
 351  */
 352 static void
 353 shutdown_halt(void *junk, int howto)
 354 {
 355         if (howto & RB_HALT) {
 356                 printf("\n");
 357                 printf("The operating system has halted.\n");
 358                 printf("Please press any key to reboot.\n\n");
 359                 switch (cngetc()) {
 360                 case -1:                /* No console, just die */
 361                         cpu_halt();
 362                         /* NOTREACHED */
 363                 default:
 364                         howto &= ~RB_HALT;
 365                         break;
 366                 }
 367         }
 368 }
 369
 370 /*
 371  * Check to see if the system paniced, pause and then reboot
 372  * according to the specified delay.
 373  */
 374 static void
 375 shutdown_panic(void *junk, int howto)
 376 {
 377         int loop;
 378
 379         if (howto & RB_DUMP) {
 380                 if (PANIC_REBOOT_WAIT_TIME != 0) {
 381                         if (PANIC_REBOOT_WAIT_TIME != -1) {
 382                                 printf("Automatic reboot in %d seconds - "
 383                                        "press a key on the console to abort\n",
 384                                         PANIC_REBOOT_WAIT_TIME);
 385                                 for (loop = PANIC_REBOOT_WAIT_TIME * 10;
 386                                      loop > 0; --loop) {
 387                                         DELAY(1000 * 100); /* 1/10th second */
 388                                         /* Did user type a key? */
 389                                         if (cncheckc() != -1)
 390                                                 break;
 391                                 }
 392                                 if (!loop)
 393                                         return;
 394                         }
 395                 } else { /* zero time specified - reboot NOW */
 396                         return;
 397                 }
 398                 printf("--> Press a key on the console to reboot,\n");
 399                 printf("--> or switch off the system now.\n");
 400                 cngetc();
 401         }
 402 }
 403
 404 /*
 405  * Everything done, now reset
 406  */
 407 static void
 408 shutdown_reset(void *junk, int howto)
 409 {
 410         printf("Rebooting...\n");
 411         DELAY(1000000); /* wait 1 sec for printf's to complete and be read */
 412         /* cpu_boot(howto); */ /* doesn't do anything at the moment */
 413         cpu_reset();
 414         /* NOTREACHED */ /* assuming reset worked */
 415 }
 416
 417 /*
 418  * Magic number for savecore
 419  *
 420  * exported (symorder) and used at least by savecore(8)
 421  *
 422  */
 423 static u_long const     dumpmag = 0x8fca0101UL;
 424
 425 static int      dumpsize = 0;           /* also for savecore */
 426
 427 static int      dodump = 1;
 428
 429 SYSCTL_INT(_machdep, OID_AUTO, do_dump, CTLFLAG_RW, &dodump, 0,
 430     "Try to perform coredump on kernel panic");
 431
 432 static int
 433 setdumpdev(dev)
 434         dev_t dev;
 435 {
 436         int psize;
 437         long newdumplo;
 438
 439         if (dev == NODEV) {
 440                 dumpdev = dev;
 441                 return (0);
 442         }
 443         psize = dev_dpsize(dev);
 444         if (psize == -1)
 445                 return (ENXIO);
 446         /*
 447          * XXX should clean up checking in dumpsys() to be more like this.
 448          */
 449         newdumplo = psize - Maxmem * (PAGE_SIZE / DEV_BSIZE);
 450         if (newdumplo <= LABELSECTOR)
 451                 return (ENOSPC);
 452         dumpdev = dev;
 453         dumplo = newdumplo;
 454         return (0);
 455 }
 456
 457
 458 /* ARGSUSED */
 459 static void dump_conf (void *dummy);
 460 static void
 461 dump_conf(dummy)
 462         void *dummy;
 463 {
 464         char *path;
 465         dev_t dev;
 466
 467         path = malloc(MNAMELEN, M_TEMP, M_WAITOK);
 468         if (TUNABLE_STR_FETCH("dumpdev", path, MNAMELEN) != 0) {
 469                 dev = getdiskbyname(path);
 470                 if (dev != NODEV)
 471                         dumpdev = dev;
 472         }
 473         free(path, M_TEMP);
 474         if (setdumpdev(dumpdev) != 0)
 475                 dumpdev = NODEV;
 476 }
 477
 478 SYSINIT(dump_conf, SI_SUB_DUMP_CONF, SI_ORDER_FIRST, dump_conf, NULL)
 479
 480 static int
 481 sysctl_kern_dumpdev(SYSCTL_HANDLER_ARGS)
 482 {
 483         int error;
 484         udev_t ndumpdev;
 485
 486         ndumpdev = dev2udev(dumpdev);
 487         error = sysctl_handle_opaque(oidp, &ndumpdev, sizeof ndumpdev, req);
 488         if (error == 0 && req->newptr != NULL)
 489                 error = setdumpdev(udev2dev(ndumpdev, 0));
 490         return (error);
 491 }
 492
 493 SYSCTL_PROC(_kern, KERN_DUMPDEV, dumpdev, CTLTYPE_OPAQUE|CTLFLAG_RW,
 494         0, sizeof dumpdev, sysctl_kern_dumpdev, "T,dev_t", "");
 495
 496 /*
 497  * Doadump comes here after turning off memory management and
 498  * getting on the dump stack, either when called above, or by
 499  * the auto-restart code.
 500  */
 501 static void
 502 dumpsys(void)
 503 {
 504         int     error;
 505
 506         savectx(&dumppcb);
 507         if (dumping++) {
 508                 printf("Dump already in progress, bailing...\n");
 509                 return;
 510         }
 511         if (!dodump)
 512                 return;
 513         if (dumpdev == NODEV)
 514                 return;
 515         dumpsize = Maxmem;
 516         printf("\ndumping to dev %s, offset %ld\n", devtoname(dumpdev), dumplo);
 517         printf("dump ");
 518         error = dev_ddump(dumpdev);
 519         if (error == 0) {
 520                 printf("succeeded\n");
 521                 return;
 522         }
 523         printf("failed, reason: ");
 524         switch (error) {
 525         case ENOSYS:
 526         case ENODEV:
 527                 printf("device doesn't support a dump routine\n");
 528                 break;
 529
 530         case ENXIO:
 531                 printf("device bad\n");
 532                 break;
 533
 534         case EFAULT:
 535                 printf("device not ready\n");
 536                 break;
 537
 538         case EINVAL:
 539                 printf("area improper\n");
 540                 break;
 541
 542         case EIO:
 543                 printf("i/o error\n");
 544                 break;
 545
 546         case EINTR:
 547                 printf("aborted from console\n");
 548                 break;
 549
 550         default:
 551                 printf("unknown, error = %d\n", error);
 552                 break;
 553         }
 554 }
 555
 556 int
 557 dumpstatus(vm_offset_t addr, off_t count)
 558 {
 559         int c;
 560
 561         if (addr % (1024 * 1024) == 0) {
 562 #ifdef HW_WDOG
 563                 if (wdog_tickler)
 564                         (*wdog_tickler)();
 565 #endif
 566                 printf("%ld ", (long)(count / (1024 * 1024)));
 567         }
 568
 569         if ((c = cncheckc()) == 0x03)
 570                 return -1;
 571         else if (c != -1)
 572                 printf("[CTRL-C to abort] ");
 573
 574         return 0;
 575 }
 576
 577 /*
 578  * Panic is called on unresolvable fatal errors.  It prints "panic: mesg",
 579  * and then reboots.  If we are called twice, then we avoid trying to sync
 580  * the disks as this often leads to recursive panics.
 581  */
 582 void
 583 panic(const char *fmt, ...)
 584 {
 585         int bootopt, newpanic;
 586         __va_list ap;
 587         static char buf[256];
 588
 589         bootopt = RB_AUTOBOOT | RB_DUMP;
 590         if (sync_on_panic == 0)
 591                 bootopt |= RB_NOSYNC;
 592         newpanic = 0;
 593         if (panicstr)
 594                 bootopt |= RB_NOSYNC;
 595         else {
 596                 panicstr = fmt;
 597                 newpanic = 1;
 598         }
 599
 600         __va_start(ap, fmt);
 601         (void)vsnprintf(buf, sizeof(buf), fmt, ap);
 602         if (panicstr == fmt)
 603                 panicstr = buf;
 604         __va_end(ap);
 605         printf("panic: %s\n", buf);
 606 #ifdef SMP
 607         /* three separate prints in case of an unmapped page and trap */
 608         printf("mp_lock = %08x; ", mp_lock);
 609         printf("cpuid = %d; ", mycpu->gd_cpuid);
 610         printf("lapic.id = %08x\n", lapic.id);
 611 #endif
 612
 613 #if defined(DDB)
 614         if (newpanic && trace_on_panic)
 615                 db_print_backtrace();
 616         if (debugger_on_panic)
 617                 Debugger ("panic");
 618 #endif
 619         boot(bootopt);
 620 }
 621
 622 /*
 623  * Support for poweroff delay.
 624  */
 625 #ifndef POWEROFF_DELAY
 626 # define POWEROFF_DELAY 5000
 627 #endif
 628 static int poweroff_delay = POWEROFF_DELAY;
 629
 630 SYSCTL_INT(_kern_shutdown, OID_AUTO, poweroff_delay, CTLFLAG_RW,
 631         &poweroff_delay, 0, "");
 632
 633 static void
 634 poweroff_wait(void *junk, int howto)
 635 {
 636         if(!(howto & RB_POWEROFF) || poweroff_delay <= 0)
 637                 return;
 638         DELAY(poweroff_delay * 1000);
 639 }
 640
 641 /*
 642  * Some system processes (e.g. syncer) need to be stopped at appropriate
 643  * points in their main loops prior to a system shutdown, so that they
 644  * won't interfere with the shutdown process (e.g. by holding a disk buf
 645  * to cause sync to fail).  For each of these system processes, register
 646  * shutdown_kproc() as a handler for one of shutdown events.
 647  */
 648 static int kproc_shutdown_wait = 60;
 649 SYSCTL_INT(_kern_shutdown, OID_AUTO, kproc_shutdown_wait, CTLFLAG_RW,
 650     &kproc_shutdown_wait, 0, "");
 651
 652 void
 653 shutdown_kproc(void *arg, int howto)
 654 {
 655         struct thread *td;
 656         struct proc *p;
 657         int error;
 658
 659         if (panicstr)
 660                 return;
 661
 662         td = (struct thread *)arg;
 663         if ((p = td->td_proc) != NULL) {
 664             printf("Waiting (max %d seconds) for system process `%s' to stop...",
 665                 kproc_shutdown_wait, p->p_comm);
 666         } else {
 667             printf("Waiting (max %d seconds) for system thread %s to stop...",
 668                 kproc_shutdown_wait, td->td_comm);
 669         }
 670         error = suspend_kproc(td, kproc_shutdown_wait * hz);
 671
 672         if (error == EWOULDBLOCK)
 673                 printf("timed out\n");
 674         else
 675                 printf("stopped\n");
 676 }