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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_witness.c
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1 /*- 2 * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Berkeley Software Design Inc's name may not be used to endorse or 13 * promote products derived from this software without specific prior 14 * written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * from BSDI $Id: mutex_witness.c,v 1.1.2.20 2000/04/27 03:10:27 cp Exp $ 29 * and BSDI $Id: synch_machdep.c,v 2.3.2.39 2000/04/27 03:10:25 cp Exp $ 30 */ 31 32 /* 33 * Implementation of the `witness' lock verifier. Originally implemented for 34 * mutexes in BSD/OS. Extended to handle generic lock objects and lock 35 * classes in FreeBSD. 36 */ 37 38 /* 39 * Main Entry: witness 40 * Pronunciation: 'wit-n&s 41 * Function: noun 42 * Etymology: Middle English witnesse, from Old English witnes knowledge, 43 * testimony, witness, from 2wit 44 * Date: before 12th century 45 * 1 : attestation of a fact or event : TESTIMONY 46 * 2 : one that gives evidence; specifically : one who testifies in 47 * a cause or before a judicial tribunal 48 * 3 : one asked to be present at a transaction so as to be able to 49 * testify to its having taken place 50 * 4 : one who has personal knowledge of something 51 * 5 a : something serving as evidence or proof : SIGN 52 * b : public affirmation by word or example of usually 53 * religious faith or conviction <the heroic witness to divine 54 * life -- Pilot> 55 * 6 capitalized : a member of the Jehovah's Witnesses 56 */ 57 58 /* 59 * Special rules concerning Giant and lock orders: 60 * 61 * 1) Giant must be acquired before any other mutexes. Stated another way, 62 * no other mutex may be held when Giant is acquired. 63 * 64 * 2) Giant must be released when blocking on a sleepable lock. 65 * 66 * This rule is less obvious, but is a result of Giant providing the same 67 * semantics as spl(). Basically, when a thread sleeps, it must release 68 * Giant. When a thread blocks on a sleepable lock, it sleeps. Hence rule 69 * 2). 70 * 71 * 3) Giant may be acquired before or after sleepable locks. 72 * 73 * This rule is also not quite as obvious. Giant may be acquired after 74 * a sleepable lock because it is a non-sleepable lock and non-sleepable 75 * locks may always be acquired while holding a sleepable lock. The second 76 * case, Giant before a sleepable lock, follows from rule 2) above. Suppose 77 * you have two threads T1 and T2 and a sleepable lock X. Suppose that T1 78 * acquires X and blocks on Giant. Then suppose that T2 acquires Giant and 79 * blocks on X. When T2 blocks on X, T2 will release Giant allowing T1 to 80 * execute. Thus, acquiring Giant both before and after a sleepable lock 81 * will not result in a lock order reversal. 82 */ 83 84 #include <sys/cdefs.h> 85 __FBSDID("$FreeBSD: releng/5.4/sys/kern/subr_witness.c 145335 2005-04-20 19:11:07Z cvs2svn $"); 86 87 #include "opt_ddb.h" 88 #include "opt_witness.h" 89 90 #include <sys/param.h> 91 #include <sys/bus.h> 92 #include <sys/kdb.h> 93 #include <sys/kernel.h> 94 #include <sys/ktr.h> 95 #include <sys/lock.h> 96 #include <sys/malloc.h> 97 #include <sys/mutex.h> 98 #include <sys/proc.h> 99 #include <sys/sysctl.h> 100 #include <sys/systm.h> 101 102 #include <ddb/ddb.h> 103 104 #include <machine/stdarg.h> 105 106 /* Define this to check for blessed mutexes */ 107 #undef BLESSING 108 109 #define WITNESS_COUNT 200 110 #define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4) 111 /* 112 * XXX: This is somewhat bogus, as we assume here that at most 1024 threads 113 * will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should 114 * probably be safe for the most part, but it's still a SWAG. 115 */ 116 #define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2 117 118 #define WITNESS_NCHILDREN 6 119 120 struct witness_child_list_entry; 121 122 struct witness { 123 const char *w_name; 124 struct lock_class *w_class; 125 STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */ 126 STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ 127 struct witness_child_list_entry *w_children; /* Great evilness... */ 128 const char *w_file; 129 int w_line; 130 u_int w_level; 131 u_int w_refcount; 132 u_char w_Giant_squawked:1; 133 u_char w_other_squawked:1; 134 u_char w_same_squawked:1; 135 u_char w_displayed:1; 136 }; 137 138 struct witness_child_list_entry { 139 struct witness_child_list_entry *wcl_next; 140 struct witness *wcl_children[WITNESS_NCHILDREN]; 141 u_int wcl_count; 142 }; 143 144 STAILQ_HEAD(witness_list, witness); 145 146 #ifdef BLESSING 147 struct witness_blessed { 148 const char *b_lock1; 149 const char *b_lock2; 150 }; 151 #endif 152 153 struct witness_order_list_entry { 154 const char *w_name; 155 struct lock_class *w_class; 156 }; 157 158 #ifdef BLESSING 159 static int blessed(struct witness *, struct witness *); 160 #endif 161 static int depart(struct witness *w); 162 static struct witness *enroll(const char *description, 163 struct lock_class *lock_class); 164 static int insertchild(struct witness *parent, struct witness *child); 165 static int isitmychild(struct witness *parent, struct witness *child); 166 static int isitmydescendant(struct witness *parent, struct witness *child); 167 static int itismychild(struct witness *parent, struct witness *child); 168 static int rebalancetree(struct witness_list *list); 169 static void removechild(struct witness *parent, struct witness *child); 170 static int reparentchildren(struct witness *newparent, 171 struct witness *oldparent); 172 static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS); 173 static void witness_displaydescendants(void(*)(const char *fmt, ...), 174 struct witness *, int indent); 175 static const char *fixup_filename(const char *file); 176 static void witness_leveldescendents(struct witness *parent, int level); 177 static void witness_levelall(void); 178 static struct witness *witness_get(void); 179 static void witness_free(struct witness *m); 180 static struct witness_child_list_entry *witness_child_get(void); 181 static void witness_child_free(struct witness_child_list_entry *wcl); 182 static struct lock_list_entry *witness_lock_list_get(void); 183 static void witness_lock_list_free(struct lock_list_entry *lle); 184 static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 185 struct lock_object *lock); 186 static void witness_list_lock(struct lock_instance *instance); 187 #ifdef DDB 188 static void witness_list(struct thread *td); 189 static void witness_display_list(void(*prnt)(const char *fmt, ...), 190 struct witness_list *list); 191 static void witness_display(void(*)(const char *fmt, ...)); 192 #endif 193 194 SYSCTL_NODE(_debug, OID_AUTO, witness, CTLFLAG_RW, 0, "Witness Locking"); 195 196 /* 197 * If set to 0, witness is disabled. If set to 1, witness performs full lock 198 * order checking for all locks. If set to 2 or higher, then witness skips 199 * the full lock order check if the lock being acquired is at a higher level 200 * (i.e. farther down in the tree) than the current lock. This last mode is 201 * somewhat experimental and not considered fully safe. At runtime, this 202 * value may be set to 0 to turn off witness. witness is not allowed be 203 * turned on once it is turned off, however. 204 */ 205 static int witness_watch = 1; 206 TUNABLE_INT("debug.witness.watch", &witness_watch); 207 SYSCTL_PROC(_debug_witness, OID_AUTO, watch, CTLFLAG_RW | CTLTYPE_INT, NULL, 0, 208 sysctl_debug_witness_watch, "I", "witness is watching lock operations"); 209 210 #ifdef KDB 211 /* 212 * When KDB is enabled and witness_kdb is set to 1, it will cause the system 213 * to drop into kdebug() when: 214 * - a lock heirarchy violation occurs 215 * - locks are held when going to sleep. 216 */ 217 #ifdef WITNESS_KDB 218 int witness_kdb = 1; 219 #else 220 int witness_kdb = 0; 221 #endif 222 TUNABLE_INT("debug.witness.kdb", &witness_kdb); 223 SYSCTL_INT(_debug_witness, OID_AUTO, kdb, CTLFLAG_RW, &witness_kdb, 0, ""); 224 225 /* 226 * When KDB is enabled and witness_trace is set to 1, it will cause the system 227 * to print a stack trace: 228 * - a lock heirarchy violation occurs 229 * - locks are held when going to sleep. 230 */ 231 int witness_trace = 1; 232 TUNABLE_INT("debug.witness.trace", &witness_trace); 233 SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, ""); 234 #endif /* KDB */ 235 236 #ifdef WITNESS_SKIPSPIN 237 int witness_skipspin = 1; 238 #else 239 int witness_skipspin = 0; 240 #endif 241 TUNABLE_INT("debug.witness.skipspin", &witness_skipspin); 242 SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN, 243 &witness_skipspin, 0, ""); 244 245 static struct mtx w_mtx; 246 static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 247 static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 248 static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 249 static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 250 static struct witness_child_list_entry *w_child_free = NULL; 251 static struct lock_list_entry *w_lock_list_free = NULL; 252 253 static struct witness w_data[WITNESS_COUNT]; 254 static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 255 static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 256 257 static struct witness_order_list_entry order_lists[] = { 258 { "proctree", &lock_class_sx }, 259 { "allproc", &lock_class_sx }, 260 { "Giant", &lock_class_mtx_sleep }, 261 { "filedesc structure", &lock_class_mtx_sleep }, 262 { "pipe mutex", &lock_class_mtx_sleep }, 263 { "sigio lock", &lock_class_mtx_sleep }, 264 { "process group", &lock_class_mtx_sleep }, 265 { "process lock", &lock_class_mtx_sleep }, 266 { "session", &lock_class_mtx_sleep }, 267 { "uidinfo hash", &lock_class_mtx_sleep }, 268 { "uidinfo struct", &lock_class_mtx_sleep }, 269 { "allprison", &lock_class_mtx_sleep }, 270 { NULL, NULL }, 271 /* 272 * Sockets 273 */ 274 { "filedesc structure", &lock_class_mtx_sleep }, 275 { "accept", &lock_class_mtx_sleep }, 276 { "so_snd", &lock_class_mtx_sleep }, 277 { "so_rcv", &lock_class_mtx_sleep }, 278 { "sellck", &lock_class_mtx_sleep }, 279 { NULL, NULL }, 280 /* 281 * Routing 282 */ 283 { "so_rcv", &lock_class_mtx_sleep }, 284 { "radix node head", &lock_class_mtx_sleep }, 285 { "rtentry", &lock_class_mtx_sleep }, 286 { "ifaddr", &lock_class_mtx_sleep }, 287 { NULL, NULL }, 288 /* 289 * UNIX Domain Sockets 290 */ 291 { "unp", &lock_class_mtx_sleep }, 292 { "so_snd", &lock_class_mtx_sleep }, 293 { NULL, NULL }, 294 /* 295 * UDP/IP 296 */ 297 { "udp", &lock_class_mtx_sleep }, 298 { "udpinp", &lock_class_mtx_sleep }, 299 { "so_snd", &lock_class_mtx_sleep }, 300 { NULL, NULL }, 301 /* 302 * TCP/IP 303 */ 304 { "tcp", &lock_class_mtx_sleep }, 305 { "tcpinp", &lock_class_mtx_sleep }, 306 { "so_snd", &lock_class_mtx_sleep }, 307 { NULL, NULL }, 308 /* 309 * SLIP 310 */ 311 { "slip_mtx", &lock_class_mtx_sleep }, 312 { "slip sc_mtx", &lock_class_mtx_sleep }, 313 { NULL, NULL }, 314 /* 315 * netatalk 316 */ 317 { "ddp_list_mtx", &lock_class_mtx_sleep }, 318 { "ddp_mtx", &lock_class_mtx_sleep }, 319 { NULL, NULL }, 320 /* 321 * BPF 322 */ 323 { "bpf global lock", &lock_class_mtx_sleep }, 324 { "bpf interface lock", &lock_class_mtx_sleep }, 325 { "bpf cdev lock", &lock_class_mtx_sleep }, 326 { NULL, NULL }, 327 /* 328 * spin locks 329 */ 330 #ifdef SMP 331 { "ap boot", &lock_class_mtx_spin }, 332 #endif 333 { "sio", &lock_class_mtx_spin }, 334 #ifdef __i386__ 335 { "cy", &lock_class_mtx_spin }, 336 #endif 337 { "uart_hwmtx", &lock_class_mtx_spin }, 338 { "sabtty", &lock_class_mtx_spin }, 339 { "zstty", &lock_class_mtx_spin }, 340 { "ng_node", &lock_class_mtx_spin }, 341 { "ng_worklist", &lock_class_mtx_spin }, 342 { "taskqueue_fast", &lock_class_mtx_spin }, 343 { "intr table", &lock_class_mtx_spin }, 344 { "ithread table lock", &lock_class_mtx_spin }, 345 { "sleepq chain", &lock_class_mtx_spin }, 346 { "sched lock", &lock_class_mtx_spin }, 347 { "turnstile chain", &lock_class_mtx_spin }, 348 { "td_contested", &lock_class_mtx_spin }, 349 { "callout", &lock_class_mtx_spin }, 350 { "entropy harvest mutex", &lock_class_mtx_spin }, 351 /* 352 * leaf locks 353 */ 354 { "allpmaps", &lock_class_mtx_spin }, 355 { "vm page queue free mutex", &lock_class_mtx_spin }, 356 { "icu", &lock_class_mtx_spin }, 357 #ifdef SMP 358 { "smp rendezvous", &lock_class_mtx_spin }, 359 #if defined(__i386__) || defined(__amd64__) 360 { "tlb", &lock_class_mtx_spin }, 361 #endif 362 #ifdef __sparc64__ 363 { "ipi", &lock_class_mtx_spin }, 364 #endif 365 #endif 366 { "clk", &lock_class_mtx_spin }, 367 { "mutex profiling lock", &lock_class_mtx_spin }, 368 { "kse zombie lock", &lock_class_mtx_spin }, 369 { "ALD Queue", &lock_class_mtx_spin }, 370 #ifdef __ia64__ 371 { "MCA spin lock", &lock_class_mtx_spin }, 372 #endif 373 #if defined(__i386__) || defined(__amd64__) 374 { "pcicfg", &lock_class_mtx_spin }, 375 #endif 376 { NULL, NULL }, 377 { NULL, NULL } 378 }; 379 380 #ifdef BLESSING 381 /* 382 * Pairs of locks which have been blessed 383 * Don't complain about order problems with blessed locks 384 */ 385 static struct witness_blessed blessed_list[] = { 386 }; 387 static int blessed_count = 388 sizeof(blessed_list) / sizeof(struct witness_blessed); 389 #endif 390 391 /* 392 * List of all locks in the system. 393 */ 394 TAILQ_HEAD(, lock_object) all_locks = TAILQ_HEAD_INITIALIZER(all_locks); 395 396 static struct mtx all_mtx = { 397 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 398 "All locks list", /* mtx_object.lo_name */ 399 "All locks list", /* mtx_object.lo_type */ 400 LO_INITIALIZED, /* mtx_object.lo_flags */ 401 { NULL, NULL }, /* mtx_object.lo_list */ 402 NULL }, /* mtx_object.lo_witness */ 403 MTX_UNOWNED, 0 /* mtx_lock, mtx_recurse */ 404 }; 405 406 /* 407 * This global is set to 0 once it becomes safe to use the witness code. 408 */ 409 static int witness_cold = 1; 410 411 /* 412 * Global variables for book keeping. 413 */ 414 static int lock_cur_cnt; 415 static int lock_max_cnt; 416 417 /* 418 * The WITNESS-enabled diagnostic code. 419 */ 420 static void 421 witness_initialize(void *dummy __unused) 422 { 423 struct lock_object *lock; 424 struct witness_order_list_entry *order; 425 struct witness *w, *w1; 426 int i; 427 428 /* 429 * We have to release Giant before initializing its witness 430 * structure so that WITNESS doesn't get confused. 431 */ 432 mtx_unlock(&Giant); 433 mtx_assert(&Giant, MA_NOTOWNED); 434 435 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 436 TAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 437 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 438 MTX_NOWITNESS); 439 for (i = 0; i < WITNESS_COUNT; i++) 440 witness_free(&w_data[i]); 441 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 442 witness_child_free(&w_childdata[i]); 443 for (i = 0; i < LOCK_CHILDCOUNT; i++) 444 witness_lock_list_free(&w_locklistdata[i]); 445 446 /* First add in all the specified order lists. */ 447 for (order = order_lists; order->w_name != NULL; order++) { 448 w = enroll(order->w_name, order->w_class); 449 if (w == NULL) 450 continue; 451 w->w_file = "order list"; 452 for (order++; order->w_name != NULL; order++) { 453 w1 = enroll(order->w_name, order->w_class); 454 if (w1 == NULL) 455 continue; 456 w1->w_file = "order list"; 457 if (!itismychild(w, w1)) 458 panic("Not enough memory for static orders!"); 459 w = w1; 460 } 461 } 462 463 /* Iterate through all locks and add them to witness. */ 464 mtx_lock(&all_mtx); 465 TAILQ_FOREACH(lock, &all_locks, lo_list) { 466 if (lock->lo_flags & LO_WITNESS) 467 lock->lo_witness = enroll(lock->lo_type, 468 lock->lo_class); 469 else 470 lock->lo_witness = NULL; 471 } 472 mtx_unlock(&all_mtx); 473 474 /* Mark the witness code as being ready for use. */ 475 atomic_store_rel_int(&witness_cold, 0); 476 477 mtx_lock(&Giant); 478 } 479 SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 480 481 static int 482 sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS) 483 { 484 int error, value; 485 486 value = witness_watch; 487 error = sysctl_handle_int(oidp, &value, 0, req); 488 if (error != 0 || req->newptr == NULL) 489 return (error); 490 error = suser(req->td); 491 if (error != 0) 492 return (error); 493 if (value == witness_watch) 494 return (0); 495 if (value != 0) 496 return (EINVAL); 497 witness_watch = 0; 498 return (0); 499 } 500 501 void 502 witness_init(struct lock_object *lock) 503 { 504 struct lock_class *class; 505 506 class = lock->lo_class; 507 if (lock->lo_flags & LO_INITIALIZED) 508 panic("%s: lock (%s) %s is already initialized", __func__, 509 class->lc_name, lock->lo_name); 510 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 511 (class->lc_flags & LC_RECURSABLE) == 0) 512 panic("%s: lock (%s) %s can not be recursable", __func__, 513 class->lc_name, lock->lo_name); 514 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 515 (class->lc_flags & LC_SLEEPABLE) == 0) 516 panic("%s: lock (%s) %s can not be sleepable", __func__, 517 class->lc_name, lock->lo_name); 518 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 519 (class->lc_flags & LC_UPGRADABLE) == 0) 520 panic("%s: lock (%s) %s can not be upgradable", __func__, 521 class->lc_name, lock->lo_name); 522 523 mtx_lock(&all_mtx); 524 TAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 525 lock->lo_flags |= LO_INITIALIZED; 526 lock_cur_cnt++; 527 if (lock_cur_cnt > lock_max_cnt) 528 lock_max_cnt = lock_cur_cnt; 529 mtx_unlock(&all_mtx); 530 if (!witness_cold && witness_watch != 0 && panicstr == NULL && 531 (lock->lo_flags & LO_WITNESS) != 0) 532 lock->lo_witness = enroll(lock->lo_type, class); 533 else 534 lock->lo_witness = NULL; 535 } 536 537 void 538 witness_destroy(struct lock_object *lock) 539 { 540 struct witness *w; 541 542 if (witness_cold) 543 panic("lock (%s) %s destroyed while witness_cold", 544 lock->lo_class->lc_name, lock->lo_name); 545 if ((lock->lo_flags & LO_INITIALIZED) == 0) 546 panic("%s: lock (%s) %s is not initialized", __func__, 547 lock->lo_class->lc_name, lock->lo_name); 548 549 /* XXX: need to verify that no one holds the lock */ 550 w = lock->lo_witness; 551 if (w != NULL) { 552 mtx_lock_spin(&w_mtx); 553 MPASS(w->w_refcount > 0); 554 w->w_refcount--; 555 556 /* 557 * Lock is already released if we have an allocation failure 558 * and depart() fails. 559 */ 560 if (w->w_refcount != 0 || depart(w)) 561 mtx_unlock_spin(&w_mtx); 562 } 563 564 mtx_lock(&all_mtx); 565 lock_cur_cnt--; 566 TAILQ_REMOVE(&all_locks, lock, lo_list); 567 lock->lo_flags &= ~LO_INITIALIZED; 568 mtx_unlock(&all_mtx); 569 } 570 571 #ifdef DDB 572 static void 573 witness_display_list(void(*prnt)(const char *fmt, ...), 574 struct witness_list *list) 575 { 576 struct witness *w; 577 578 STAILQ_FOREACH(w, list, w_typelist) { 579 if (w->w_file == NULL || w->w_level > 0) 580 continue; 581 /* 582 * This lock has no anscestors, display its descendants. 583 */ 584 witness_displaydescendants(prnt, w, 0); 585 } 586 } 587 588 static void 589 witness_display(void(*prnt)(const char *fmt, ...)) 590 { 591 struct witness *w; 592 593 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 594 witness_levelall(); 595 596 /* Clear all the displayed flags. */ 597 STAILQ_FOREACH(w, &w_all, w_list) { 598 w->w_displayed = 0; 599 } 600 601 /* 602 * First, handle sleep locks which have been acquired at least 603 * once. 604 */ 605 prnt("Sleep locks:\n"); 606 witness_display_list(prnt, &w_sleep); 607 608 /* 609 * Now do spin locks which have been acquired at least once. 610 */ 611 prnt("\nSpin locks:\n"); 612 witness_display_list(prnt, &w_spin); 613 614 /* 615 * Finally, any locks which have not been acquired yet. 616 */ 617 prnt("\nLocks which were never acquired:\n"); 618 STAILQ_FOREACH(w, &w_all, w_list) { 619 if (w->w_file != NULL || w->w_refcount == 0) 620 continue; 621 prnt("%s\n", w->w_name); 622 } 623 } 624 #endif /* DDB */ 625 626 /* Trim useless garbage from filenames. */ 627 static const char * 628 fixup_filename(const char *file) 629 { 630 631 if (file == NULL) 632 return (NULL); 633 while (strncmp(file, "../", 3) == 0) 634 file += 3; 635 return (file); 636 } 637 638 int 639 witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) 640 { 641 642 if (witness_watch == 0 || panicstr != NULL) 643 return (0); 644 645 /* Require locks that witness knows about. */ 646 if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || 647 lock2->lo_witness == NULL) 648 return (EINVAL); 649 650 MPASS(!mtx_owned(&w_mtx)); 651 mtx_lock_spin(&w_mtx); 652 653 /* 654 * If we already have either an explicit or implied lock order that 655 * is the other way around, then return an error. 656 */ 657 if (isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { 658 mtx_unlock_spin(&w_mtx); 659 return (EDOOFUS); 660 } 661 662 /* Try to add the new order. */ 663 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 664 lock2->lo_type, lock1->lo_type); 665 if (!itismychild(lock1->lo_witness, lock2->lo_witness)) 666 return (ENOMEM); 667 mtx_unlock_spin(&w_mtx); 668 return (0); 669 } 670 671 void 672 witness_checkorder(struct lock_object *lock, int flags, const char *file, 673 int line) 674 { 675 struct lock_list_entry **lock_list, *lle; 676 struct lock_instance *lock1, *lock2; 677 struct lock_class *class; 678 struct witness *w, *w1; 679 struct thread *td; 680 int i, j; 681 682 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 683 panicstr != NULL) 684 return; 685 686 /* 687 * Try locks do not block if they fail to acquire the lock, thus 688 * there is no danger of deadlocks or of switching while holding a 689 * spin lock if we acquire a lock via a try operation. This 690 * function shouldn't even be called for try locks, so panic if 691 * that happens. 692 */ 693 if (flags & LOP_TRYLOCK) 694 panic("%s should not be called for try lock operations", 695 __func__); 696 697 w = lock->lo_witness; 698 class = lock->lo_class; 699 td = curthread; 700 file = fixup_filename(file); 701 702 if (class->lc_flags & LC_SLEEPLOCK) { 703 /* 704 * Since spin locks include a critical section, this check 705 * implicitly enforces a lock order of all sleep locks before 706 * all spin locks. 707 */ 708 if (td->td_critnest != 0) 709 panic("blockable sleep lock (%s) %s @ %s:%d", 710 class->lc_name, lock->lo_name, file, line); 711 712 /* 713 * If this is the first lock acquired then just return as 714 * no order checking is needed. 715 */ 716 if (td->td_sleeplocks == NULL) 717 return; 718 lock_list = &td->td_sleeplocks; 719 } else { 720 /* 721 * If this is the first lock, just return as no order 722 * checking is needed. We check this in both if clauses 723 * here as unifying the check would require us to use a 724 * critical section to ensure we don't migrate while doing 725 * the check. Note that if this is not the first lock, we 726 * are already in a critical section and are safe for the 727 * rest of the check. 728 */ 729 if (PCPU_GET(spinlocks) == NULL) 730 return; 731 lock_list = PCPU_PTR(spinlocks); 732 } 733 734 /* 735 * Check to see if we are recursing on a lock we already own. If 736 * so, make sure that we don't mismatch exclusive and shared lock 737 * acquires. 738 */ 739 lock1 = find_instance(*lock_list, lock); 740 if (lock1 != NULL) { 741 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 742 (flags & LOP_EXCLUSIVE) == 0) { 743 printf("shared lock of (%s) %s @ %s:%d\n", 744 class->lc_name, lock->lo_name, file, line); 745 printf("while exclusively locked from %s:%d\n", 746 lock1->li_file, lock1->li_line); 747 panic("share->excl"); 748 } 749 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 750 (flags & LOP_EXCLUSIVE) != 0) { 751 printf("exclusive lock of (%s) %s @ %s:%d\n", 752 class->lc_name, lock->lo_name, file, line); 753 printf("while share locked from %s:%d\n", 754 lock1->li_file, lock1->li_line); 755 panic("excl->share"); 756 } 757 return; 758 } 759 760 /* 761 * Try locks do not block if they fail to acquire the lock, thus 762 * there is no danger of deadlocks or of switching while holding a 763 * spin lock if we acquire a lock via a try operation. 764 */ 765 if (flags & LOP_TRYLOCK) 766 return; 767 768 /* 769 * Check for duplicate locks of the same type. Note that we only 770 * have to check for this on the last lock we just acquired. Any 771 * other cases will be caught as lock order violations. 772 */ 773 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 774 w1 = lock1->li_lock->lo_witness; 775 if (w1 == w) { 776 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK)) 777 return; 778 w->w_same_squawked = 1; 779 printf("acquiring duplicate lock of same type: \"%s\"\n", 780 lock->lo_type); 781 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 782 lock1->li_file, lock1->li_line); 783 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 784 #ifdef KDB 785 goto debugger; 786 #else 787 return; 788 #endif 789 } 790 MPASS(!mtx_owned(&w_mtx)); 791 mtx_lock_spin(&w_mtx); 792 /* 793 * If we have a known higher number just say ok 794 */ 795 if (witness_watch > 1 && w->w_level > w1->w_level) { 796 mtx_unlock_spin(&w_mtx); 797 return; 798 } 799 /* 800 * If we know that the the lock we are acquiring comes after 801 * the lock we most recently acquired in the lock order tree, 802 * then there is no need for any further checks. 803 */ 804 if (isitmydescendant(w1, w)) { 805 mtx_unlock_spin(&w_mtx); 806 return; 807 } 808 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 809 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 810 811 MPASS(j < WITNESS_COUNT); 812 lock1 = &lle->ll_children[i]; 813 w1 = lock1->li_lock->lo_witness; 814 815 /* 816 * If this lock doesn't undergo witness checking, 817 * then skip it. 818 */ 819 if (w1 == NULL) { 820 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 821 ("lock missing witness structure")); 822 continue; 823 } 824 /* 825 * If we are locking Giant and this is a sleepable 826 * lock, then skip it. 827 */ 828 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && 829 lock == &Giant.mtx_object) 830 continue; 831 /* 832 * If we are locking a sleepable lock and this lock 833 * is Giant, then skip it. 834 */ 835 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 836 lock1->li_lock == &Giant.mtx_object) 837 continue; 838 /* 839 * If we are locking a sleepable lock and this lock 840 * isn't sleepable, we want to treat it as a lock 841 * order violation to enfore a general lock order of 842 * sleepable locks before non-sleepable locks. 843 */ 844 if (!((lock->lo_flags & LO_SLEEPABLE) != 0 && 845 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 846 /* 847 * Check the lock order hierarchy for a reveresal. 848 */ 849 if (!isitmydescendant(w, w1)) 850 continue; 851 /* 852 * We have a lock order violation, check to see if it 853 * is allowed or has already been yelled about. 854 */ 855 mtx_unlock_spin(&w_mtx); 856 #ifdef BLESSING 857 /* 858 * If the lock order is blessed, just bail. We don't 859 * look for other lock order violations though, which 860 * may be a bug. 861 */ 862 if (blessed(w, w1)) 863 return; 864 #endif 865 if (lock1->li_lock == &Giant.mtx_object) { 866 if (w1->w_Giant_squawked) 867 return; 868 else 869 w1->w_Giant_squawked = 1; 870 } else { 871 if (w1->w_other_squawked) 872 return; 873 else 874 w1->w_other_squawked = 1; 875 } 876 /* 877 * Ok, yell about it. 878 */ 879 printf("lock order reversal\n"); 880 /* 881 * Try to locate an earlier lock with 882 * witness w in our list. 883 */ 884 do { 885 lock2 = &lle->ll_children[i]; 886 MPASS(lock2->li_lock != NULL); 887 if (lock2->li_lock->lo_witness == w) 888 break; 889 if (i == 0 && lle->ll_next != NULL) { 890 lle = lle->ll_next; 891 i = lle->ll_count - 1; 892 MPASS(i >= 0 && i < LOCK_NCHILDREN); 893 } else 894 i--; 895 } while (i >= 0); 896 if (i < 0) { 897 printf(" 1st %p %s (%s) @ %s:%d\n", 898 lock1->li_lock, lock1->li_lock->lo_name, 899 lock1->li_lock->lo_type, lock1->li_file, 900 lock1->li_line); 901 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 902 lock->lo_name, lock->lo_type, file, line); 903 } else { 904 printf(" 1st %p %s (%s) @ %s:%d\n", 905 lock2->li_lock, lock2->li_lock->lo_name, 906 lock2->li_lock->lo_type, lock2->li_file, 907 lock2->li_line); 908 printf(" 2nd %p %s (%s) @ %s:%d\n", 909 lock1->li_lock, lock1->li_lock->lo_name, 910 lock1->li_lock->lo_type, lock1->li_file, 911 lock1->li_line); 912 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 913 lock->lo_name, lock->lo_type, file, line); 914 } 915 #ifdef KDB 916 goto debugger; 917 #else 918 return; 919 #endif 920 } 921 } 922 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 923 /* 924 * If requested, build a new lock order. However, don't build a new 925 * relationship between a sleepable lock and Giant if it is in the 926 * wrong direction. The correct lock order is that sleepable locks 927 * always come before Giant. 928 */ 929 if (flags & LOP_NEWORDER && 930 !(lock1->li_lock == &Giant.mtx_object && 931 (lock->lo_flags & LO_SLEEPABLE) != 0)) { 932 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 933 lock->lo_type, lock1->li_lock->lo_type); 934 if (!itismychild(lock1->li_lock->lo_witness, w)) 935 /* Witness is dead. */ 936 return; 937 } 938 mtx_unlock_spin(&w_mtx); 939 return; 940 941 #ifdef KDB 942 debugger: 943 if (witness_trace) 944 kdb_backtrace(); 945 if (witness_kdb) 946 kdb_enter(__func__); 947 #endif 948 } 949 950 void 951 witness_lock(struct lock_object *lock, int flags, const char *file, int line) 952 { 953 struct lock_list_entry **lock_list, *lle; 954 struct lock_instance *instance; 955 struct witness *w; 956 struct thread *td; 957 958 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 959 panicstr != NULL) 960 return; 961 w = lock->lo_witness; 962 td = curthread; 963 file = fixup_filename(file); 964 965 /* Determine lock list for this lock. */ 966 if (lock->lo_class->lc_flags & LC_SLEEPLOCK) 967 lock_list = &td->td_sleeplocks; 968 else 969 lock_list = PCPU_PTR(spinlocks); 970 971 /* Check to see if we are recursing on a lock we already own. */ 972 instance = find_instance(*lock_list, lock); 973 if (instance != NULL) { 974 instance->li_flags++; 975 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 976 td->td_proc->p_pid, lock->lo_name, 977 instance->li_flags & LI_RECURSEMASK); 978 instance->li_file = file; 979 instance->li_line = line; 980 return; 981 } 982 983 /* Update per-witness last file and line acquire. */ 984 w->w_file = file; 985 w->w_line = line; 986 987 /* Find the next open lock instance in the list and fill it. */ 988 lle = *lock_list; 989 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 990 lle = witness_lock_list_get(); 991 if (lle == NULL) 992 return; 993 lle->ll_next = *lock_list; 994 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 995 td->td_proc->p_pid, lle); 996 *lock_list = lle; 997 } 998 instance = &lle->ll_children[lle->ll_count++]; 999 instance->li_lock = lock; 1000 instance->li_line = line; 1001 instance->li_file = file; 1002 if ((flags & LOP_EXCLUSIVE) != 0) 1003 instance->li_flags = LI_EXCLUSIVE; 1004 else 1005 instance->li_flags = 0; 1006 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 1007 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 1008 } 1009 1010 void 1011 witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 1012 { 1013 struct lock_instance *instance; 1014 struct lock_class *class; 1015 1016 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1017 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1018 return; 1019 class = lock->lo_class; 1020 file = fixup_filename(file); 1021 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1022 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 1023 class->lc_name, lock->lo_name, file, line); 1024 if ((flags & LOP_TRYLOCK) == 0) 1025 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 1026 lock->lo_name, file, line); 1027 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1028 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 1029 class->lc_name, lock->lo_name, file, line); 1030 instance = find_instance(curthread->td_sleeplocks, lock); 1031 if (instance == NULL) 1032 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 1033 class->lc_name, lock->lo_name, file, line); 1034 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 1035 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 1036 class->lc_name, lock->lo_name, file, line); 1037 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1038 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 1039 class->lc_name, lock->lo_name, 1040 instance->li_flags & LI_RECURSEMASK, file, line); 1041 instance->li_flags |= LI_EXCLUSIVE; 1042 } 1043 1044 void 1045 witness_downgrade(struct lock_object *lock, int flags, const char *file, 1046 int line) 1047 { 1048 struct lock_instance *instance; 1049 struct lock_class *class; 1050 1051 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1052 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1053 return; 1054 class = lock->lo_class; 1055 file = fixup_filename(file); 1056 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1057 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 1058 class->lc_name, lock->lo_name, file, line); 1059 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1060 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 1061 class->lc_name, lock->lo_name, file, line); 1062 instance = find_instance(curthread->td_sleeplocks, lock); 1063 if (instance == NULL) 1064 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 1065 class->lc_name, lock->lo_name, file, line); 1066 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 1067 panic("downgrade of shared lock (%s) %s @ %s:%d", 1068 class->lc_name, lock->lo_name, file, line); 1069 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1070 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 1071 class->lc_name, lock->lo_name, 1072 instance->li_flags & LI_RECURSEMASK, file, line); 1073 instance->li_flags &= ~LI_EXCLUSIVE; 1074 } 1075 1076 void 1077 witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 1078 { 1079 struct lock_list_entry **lock_list, *lle; 1080 struct lock_instance *instance; 1081 struct lock_class *class; 1082 struct thread *td; 1083 register_t s; 1084 int i, j; 1085 1086 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1087 panicstr != NULL) 1088 return; 1089 td = curthread; 1090 class = lock->lo_class; 1091 file = fixup_filename(file); 1092 1093 /* Find lock instance associated with this lock. */ 1094 if (class->lc_flags & LC_SLEEPLOCK) 1095 lock_list = &td->td_sleeplocks; 1096 else 1097 lock_list = PCPU_PTR(spinlocks); 1098 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 1099 for (i = 0; i < (*lock_list)->ll_count; i++) { 1100 instance = &(*lock_list)->ll_children[i]; 1101 if (instance->li_lock == lock) 1102 goto found; 1103 } 1104 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 1105 file, line); 1106 found: 1107 1108 /* First, check for shared/exclusive mismatches. */ 1109 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 1110 (flags & LOP_EXCLUSIVE) == 0) { 1111 printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name, 1112 lock->lo_name, file, line); 1113 printf("while exclusively locked from %s:%d\n", 1114 instance->li_file, instance->li_line); 1115 panic("excl->ushare"); 1116 } 1117 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 1118 (flags & LOP_EXCLUSIVE) != 0) { 1119 printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name, 1120 lock->lo_name, file, line); 1121 printf("while share locked from %s:%d\n", instance->li_file, 1122 instance->li_line); 1123 panic("share->uexcl"); 1124 } 1125 1126 /* If we are recursed, unrecurse. */ 1127 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 1128 CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, 1129 td->td_proc->p_pid, instance->li_lock->lo_name, 1130 instance->li_flags); 1131 instance->li_flags--; 1132 return; 1133 } 1134 1135 /* Otherwise, remove this item from the list. */ 1136 s = intr_disable(); 1137 CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, 1138 td->td_proc->p_pid, instance->li_lock->lo_name, 1139 (*lock_list)->ll_count - 1); 1140 for (j = i; j < (*lock_list)->ll_count - 1; j++) 1141 (*lock_list)->ll_children[j] = 1142 (*lock_list)->ll_children[j + 1]; 1143 (*lock_list)->ll_count--; 1144 intr_restore(s); 1145 1146 /* If this lock list entry is now empty, free it. */ 1147 if ((*lock_list)->ll_count == 0) { 1148 lle = *lock_list; 1149 *lock_list = lle->ll_next; 1150 CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, 1151 td->td_proc->p_pid, lle); 1152 witness_lock_list_free(lle); 1153 } 1154 } 1155 1156 /* 1157 * Warn if any locks other than 'lock' are held. Flags can be passed in to 1158 * exempt Giant and sleepable locks from the checks as well. If any 1159 * non-exempt locks are held, then a supplied message is printed to the 1160 * console along with a list of the offending locks. If indicated in the 1161 * flags then a failure results in a panic as well. 1162 */ 1163 int 1164 witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) 1165 { 1166 struct lock_list_entry *lle; 1167 struct lock_instance *lock1; 1168 struct thread *td; 1169 va_list ap; 1170 int i, n; 1171 1172 if (witness_cold || witness_watch == 0 || panicstr != NULL) 1173 return (0); 1174 n = 0; 1175 td = curthread; 1176 for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next) 1177 for (i = lle->ll_count - 1; i >= 0; i--) { 1178 lock1 = &lle->ll_children[i]; 1179 if (lock1->li_lock == lock) 1180 continue; 1181 if (flags & WARN_GIANTOK && 1182 lock1->li_lock == &Giant.mtx_object) 1183 continue; 1184 if (flags & WARN_SLEEPOK && 1185 (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) 1186 continue; 1187 if (n == 0) { 1188 va_start(ap, fmt); 1189 vprintf(fmt, ap); 1190 va_end(ap); 1191 printf(" with the following"); 1192 if (flags & WARN_SLEEPOK) 1193 printf(" non-sleepable"); 1194 printf(" locks held:\n"); 1195 } 1196 n++; 1197 witness_list_lock(lock1); 1198 } 1199 if (PCPU_GET(spinlocks) != NULL) { 1200 /* 1201 * Since we already hold a spinlock preemption is 1202 * already blocked. 1203 */ 1204 if (n == 0) { 1205 va_start(ap, fmt); 1206 vprintf(fmt, ap); 1207 va_end(ap); 1208 printf(" with the following"); 1209 if (flags & WARN_SLEEPOK) 1210 printf(" non-sleepable"); 1211 printf(" locks held:\n"); 1212 } 1213 n += witness_list_locks(PCPU_PTR(spinlocks)); 1214 } 1215 if (flags & WARN_PANIC && n) 1216 panic("witness_warn"); 1217 #ifdef KDB 1218 else if (witness_kdb && n) 1219 kdb_enter(__func__); 1220 else if (witness_trace && n) 1221 kdb_backtrace(); 1222 #endif 1223 return (n); 1224 } 1225 1226 const char * 1227 witness_file(struct lock_object *lock) 1228 { 1229 struct witness *w; 1230 1231 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1232 return ("?"); 1233 w = lock->lo_witness; 1234 return (w->w_file); 1235 } 1236 1237 int 1238 witness_line(struct lock_object *lock) 1239 { 1240 struct witness *w; 1241 1242 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1243 return (0); 1244 w = lock->lo_witness; 1245 return (w->w_line); 1246 } 1247 1248 static struct witness * 1249 enroll(const char *description, struct lock_class *lock_class) 1250 { 1251 struct witness *w; 1252 1253 if (witness_watch == 0 || panicstr != NULL) 1254 return (NULL); 1255 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 1256 return (NULL); 1257 mtx_lock_spin(&w_mtx); 1258 STAILQ_FOREACH(w, &w_all, w_list) { 1259 if (w->w_name == description || (w->w_refcount > 0 && 1260 strcmp(description, w->w_name) == 0)) { 1261 w->w_refcount++; 1262 mtx_unlock_spin(&w_mtx); 1263 if (lock_class != w->w_class) 1264 panic( 1265 "lock (%s) %s does not match earlier (%s) lock", 1266 description, lock_class->lc_name, 1267 w->w_class->lc_name); 1268 return (w); 1269 } 1270 } 1271 /* 1272 * This isn't quite right, as witness_cold is still 0 while we 1273 * enroll all the locks initialized before witness_initialize(). 1274 */ 1275 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 1276 mtx_unlock_spin(&w_mtx); 1277 panic("spin lock %s not in order list", description); 1278 } 1279 if ((w = witness_get()) == NULL) 1280 return (NULL); 1281 w->w_name = description; 1282 w->w_class = lock_class; 1283 w->w_refcount = 1; 1284 STAILQ_INSERT_HEAD(&w_all, w, w_list); 1285 if (lock_class->lc_flags & LC_SPINLOCK) 1286 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 1287 else if (lock_class->lc_flags & LC_SLEEPLOCK) 1288 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 1289 else { 1290 mtx_unlock_spin(&w_mtx); 1291 panic("lock class %s is not sleep or spin", 1292 lock_class->lc_name); 1293 } 1294 mtx_unlock_spin(&w_mtx); 1295 return (w); 1296 } 1297 1298 /* Don't let the door bang you on the way out... */ 1299 static int 1300 depart(struct witness *w) 1301 { 1302 struct witness_child_list_entry *wcl, *nwcl; 1303 struct witness_list *list; 1304 struct witness *parent; 1305 1306 MPASS(w->w_refcount == 0); 1307 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1308 list = &w_sleep; 1309 else 1310 list = &w_spin; 1311 /* 1312 * First, we run through the entire tree looking for any 1313 * witnesses that the outgoing witness is a child of. For 1314 * each parent that we find, we reparent all the direct 1315 * children of the outgoing witness to its parent. 1316 */ 1317 STAILQ_FOREACH(parent, list, w_typelist) { 1318 if (!isitmychild(parent, w)) 1319 continue; 1320 removechild(parent, w); 1321 if (!reparentchildren(parent, w)) 1322 return (0); 1323 } 1324 1325 /* 1326 * Now we go through and free up the child list of the 1327 * outgoing witness. 1328 */ 1329 for (wcl = w->w_children; wcl != NULL; wcl = nwcl) { 1330 nwcl = wcl->wcl_next; 1331 witness_child_free(wcl); 1332 } 1333 1334 /* 1335 * Detach from various lists and free. 1336 */ 1337 STAILQ_REMOVE(list, w, witness, w_typelist); 1338 STAILQ_REMOVE(&w_all, w, witness, w_list); 1339 witness_free(w); 1340 1341 /* Finally, fixup the tree. */ 1342 return (rebalancetree(list)); 1343 } 1344 1345 /* 1346 * Prune an entire lock order tree. We look for cases where a lock 1347 * is now both a descendant and a direct child of a given lock. In 1348 * that case, we want to remove the direct child link from the tree. 1349 * 1350 * Returns false if insertchild() fails. 1351 */ 1352 static int 1353 rebalancetree(struct witness_list *list) 1354 { 1355 struct witness *child, *parent; 1356 1357 STAILQ_FOREACH(child, list, w_typelist) { 1358 STAILQ_FOREACH(parent, list, w_typelist) { 1359 if (!isitmychild(parent, child)) 1360 continue; 1361 removechild(parent, child); 1362 if (isitmydescendant(parent, child)) 1363 continue; 1364 if (!insertchild(parent, child)) 1365 return (0); 1366 } 1367 } 1368 witness_levelall(); 1369 return (1); 1370 } 1371 1372 /* 1373 * Add "child" as a direct child of "parent". Returns false if 1374 * we fail due to out of memory. 1375 */ 1376 static int 1377 insertchild(struct witness *parent, struct witness *child) 1378 { 1379 struct witness_child_list_entry **wcl; 1380 1381 MPASS(child != NULL && parent != NULL); 1382 1383 /* 1384 * Insert "child" after "parent" 1385 */ 1386 wcl = &parent->w_children; 1387 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1388 wcl = &(*wcl)->wcl_next; 1389 if (*wcl == NULL) { 1390 *wcl = witness_child_get(); 1391 if (*wcl == NULL) 1392 return (0); 1393 } 1394 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1395 1396 return (1); 1397 } 1398 1399 /* 1400 * Make all the direct descendants of oldparent be direct descendants 1401 * of newparent. 1402 */ 1403 static int 1404 reparentchildren(struct witness *newparent, struct witness *oldparent) 1405 { 1406 struct witness_child_list_entry *wcl; 1407 int i; 1408 1409 /* Avoid making a witness a child of itself. */ 1410 MPASS(!isitmychild(oldparent, newparent)); 1411 1412 for (wcl = oldparent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1413 for (i = 0; i < wcl->wcl_count; i++) 1414 if (!insertchild(newparent, wcl->wcl_children[i])) 1415 return (0); 1416 return (1); 1417 } 1418 1419 static int 1420 itismychild(struct witness *parent, struct witness *child) 1421 { 1422 struct witness_list *list; 1423 1424 MPASS(child != NULL && parent != NULL); 1425 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 1426 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 1427 panic( 1428 "%s: parent (%s) and child (%s) are not the same lock type", 1429 __func__, parent->w_class->lc_name, 1430 child->w_class->lc_name); 1431 1432 if (!insertchild(parent, child)) 1433 return (0); 1434 1435 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1436 list = &w_sleep; 1437 else 1438 list = &w_spin; 1439 return (rebalancetree(list)); 1440 } 1441 1442 static void 1443 removechild(struct witness *parent, struct witness *child) 1444 { 1445 struct witness_child_list_entry **wcl, *wcl1; 1446 int i; 1447 1448 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1449 for (i = 0; i < (*wcl)->wcl_count; i++) 1450 if ((*wcl)->wcl_children[i] == child) 1451 goto found; 1452 return; 1453 found: 1454 (*wcl)->wcl_count--; 1455 if ((*wcl)->wcl_count > i) 1456 (*wcl)->wcl_children[i] = 1457 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1458 MPASS((*wcl)->wcl_children[i] != NULL); 1459 if ((*wcl)->wcl_count != 0) 1460 return; 1461 wcl1 = *wcl; 1462 *wcl = wcl1->wcl_next; 1463 witness_child_free(wcl1); 1464 } 1465 1466 static int 1467 isitmychild(struct witness *parent, struct witness *child) 1468 { 1469 struct witness_child_list_entry *wcl; 1470 int i; 1471 1472 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1473 for (i = 0; i < wcl->wcl_count; i++) { 1474 if (wcl->wcl_children[i] == child) 1475 return (1); 1476 } 1477 } 1478 return (0); 1479 } 1480 1481 static int 1482 isitmydescendant(struct witness *parent, struct witness *child) 1483 { 1484 struct witness_child_list_entry *wcl; 1485 int i, j; 1486 1487 if (isitmychild(parent, child)) 1488 return (1); 1489 j = 0; 1490 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1491 MPASS(j < 1000); 1492 for (i = 0; i < wcl->wcl_count; i++) { 1493 if (isitmydescendant(wcl->wcl_children[i], child)) 1494 return (1); 1495 } 1496 j++; 1497 } 1498 return (0); 1499 } 1500 1501 static void 1502 witness_levelall (void) 1503 { 1504 struct witness_list *list; 1505 struct witness *w, *w1; 1506 1507 /* 1508 * First clear all levels. 1509 */ 1510 STAILQ_FOREACH(w, &w_all, w_list) { 1511 w->w_level = 0; 1512 } 1513 1514 /* 1515 * Look for locks with no parent and level all their descendants. 1516 */ 1517 STAILQ_FOREACH(w, &w_all, w_list) { 1518 /* 1519 * This is just an optimization, technically we could get 1520 * away just walking the all list each time. 1521 */ 1522 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1523 list = &w_sleep; 1524 else 1525 list = &w_spin; 1526 STAILQ_FOREACH(w1, list, w_typelist) { 1527 if (isitmychild(w1, w)) 1528 goto skip; 1529 } 1530 witness_leveldescendents(w, 0); 1531 skip: 1532 ; /* silence GCC 3.x */ 1533 } 1534 } 1535 1536 static void 1537 witness_leveldescendents(struct witness *parent, int level) 1538 { 1539 struct witness_child_list_entry *wcl; 1540 int i; 1541 1542 if (parent->w_level < level) 1543 parent->w_level = level; 1544 level++; 1545 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1546 for (i = 0; i < wcl->wcl_count; i++) 1547 witness_leveldescendents(wcl->wcl_children[i], level); 1548 } 1549 1550 static void 1551 witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1552 struct witness *parent, int indent) 1553 { 1554 struct witness_child_list_entry *wcl; 1555 int i, level; 1556 1557 level = parent->w_level; 1558 prnt("%-2d", level); 1559 for (i = 0; i < indent; i++) 1560 prnt(" "); 1561 if (parent->w_refcount > 0) 1562 prnt("%s", parent->w_name); 1563 else 1564 prnt("(dead)"); 1565 if (parent->w_displayed) { 1566 prnt(" -- (already displayed)\n"); 1567 return; 1568 } 1569 parent->w_displayed = 1; 1570 if (parent->w_refcount > 0) { 1571 if (parent->w_file != NULL) 1572 prnt(" -- last acquired @ %s:%d", parent->w_file, 1573 parent->w_line); 1574 } 1575 prnt("\n"); 1576 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1577 for (i = 0; i < wcl->wcl_count; i++) 1578 witness_displaydescendants(prnt, 1579 wcl->wcl_children[i], indent + 1); 1580 } 1581 1582 #ifdef BLESSING 1583 static int 1584 blessed(struct witness *w1, struct witness *w2) 1585 { 1586 int i; 1587 struct witness_blessed *b; 1588 1589 for (i = 0; i < blessed_count; i++) { 1590 b = &blessed_list[i]; 1591 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1592 if (strcmp(w2->w_name, b->b_lock2) == 0) 1593 return (1); 1594 continue; 1595 } 1596 if (strcmp(w1->w_name, b->b_lock2) == 0) 1597 if (strcmp(w2->w_name, b->b_lock1) == 0) 1598 return (1); 1599 } 1600 return (0); 1601 } 1602 #endif 1603 1604 static struct witness * 1605 witness_get(void) 1606 { 1607 struct witness *w; 1608 1609 if (witness_watch == 0) { 1610 mtx_unlock_spin(&w_mtx); 1611 return (NULL); 1612 } 1613 if (STAILQ_EMPTY(&w_free)) { 1614 witness_watch = 0; 1615 mtx_unlock_spin(&w_mtx); 1616 printf("%s: witness exhausted\n", __func__); 1617 return (NULL); 1618 } 1619 w = STAILQ_FIRST(&w_free); 1620 STAILQ_REMOVE_HEAD(&w_free, w_list); 1621 bzero(w, sizeof(*w)); 1622 return (w); 1623 } 1624 1625 static void 1626 witness_free(struct witness *w) 1627 { 1628 1629 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1630 } 1631 1632 static struct witness_child_list_entry * 1633 witness_child_get(void) 1634 { 1635 struct witness_child_list_entry *wcl; 1636 1637 if (witness_watch == 0) { 1638 mtx_unlock_spin(&w_mtx); 1639 return (NULL); 1640 } 1641 wcl = w_child_free; 1642 if (wcl == NULL) { 1643 witness_watch = 0; 1644 mtx_unlock_spin(&w_mtx); 1645 printf("%s: witness exhausted\n", __func__); 1646 return (NULL); 1647 } 1648 w_child_free = wcl->wcl_next; 1649 bzero(wcl, sizeof(*wcl)); 1650 return (wcl); 1651 } 1652 1653 static void 1654 witness_child_free(struct witness_child_list_entry *wcl) 1655 { 1656 1657 wcl->wcl_next = w_child_free; 1658 w_child_free = wcl; 1659 } 1660 1661 static struct lock_list_entry * 1662 witness_lock_list_get(void) 1663 { 1664 struct lock_list_entry *lle; 1665 1666 if (witness_watch == 0) 1667 return (NULL); 1668 mtx_lock_spin(&w_mtx); 1669 lle = w_lock_list_free; 1670 if (lle == NULL) { 1671 witness_watch = 0; 1672 mtx_unlock_spin(&w_mtx); 1673 printf("%s: witness exhausted\n", __func__); 1674 return (NULL); 1675 } 1676 w_lock_list_free = lle->ll_next; 1677 mtx_unlock_spin(&w_mtx); 1678 bzero(lle, sizeof(*lle)); 1679 return (lle); 1680 } 1681 1682 static void 1683 witness_lock_list_free(struct lock_list_entry *lle) 1684 { 1685 1686 mtx_lock_spin(&w_mtx); 1687 lle->ll_next = w_lock_list_free; 1688 w_lock_list_free = lle; 1689 mtx_unlock_spin(&w_mtx); 1690 } 1691 1692 static struct lock_instance * 1693 find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1694 { 1695 struct lock_list_entry *lle; 1696 struct lock_instance *instance; 1697 int i; 1698 1699 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1700 for (i = lle->ll_count - 1; i >= 0; i--) { 1701 instance = &lle->ll_children[i]; 1702 if (instance->li_lock == lock) 1703 return (instance); 1704 } 1705 return (NULL); 1706 } 1707 1708 static void 1709 witness_list_lock(struct lock_instance *instance) 1710 { 1711 struct lock_object *lock; 1712 1713 lock = instance->li_lock; 1714 printf("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1715 "exclusive" : "shared", lock->lo_class->lc_name, lock->lo_name); 1716 if (lock->lo_type != lock->lo_name) 1717 printf(" (%s)", lock->lo_type); 1718 printf(" r = %d (%p) locked @ %s:%d\n", 1719 instance->li_flags & LI_RECURSEMASK, lock, instance->li_file, 1720 instance->li_line); 1721 } 1722 1723 #ifdef DDB 1724 static int 1725 witness_thread_has_locks(struct thread *td) 1726 { 1727 1728 return (td->td_sleeplocks != NULL); 1729 } 1730 1731 static int 1732 witness_proc_has_locks(struct proc *p) 1733 { 1734 struct thread *td; 1735 1736 FOREACH_THREAD_IN_PROC(p, td) { 1737 if (witness_thread_has_locks(td)) 1738 return (1); 1739 } 1740 return (0); 1741 } 1742 #endif 1743 1744 int 1745 witness_list_locks(struct lock_list_entry **lock_list) 1746 { 1747 struct lock_list_entry *lle; 1748 int i, nheld; 1749 1750 nheld = 0; 1751 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1752 for (i = lle->ll_count - 1; i >= 0; i--) { 1753 witness_list_lock(&lle->ll_children[i]); 1754 nheld++; 1755 } 1756 return (nheld); 1757 } 1758 1759 /* 1760 * This is a bit risky at best. We call this function when we have timed 1761 * out acquiring a spin lock, and we assume that the other CPU is stuck 1762 * with this lock held. So, we go groveling around in the other CPU's 1763 * per-cpu data to try to find the lock instance for this spin lock to 1764 * see when it was last acquired. 1765 */ 1766 void 1767 witness_display_spinlock(struct lock_object *lock, struct thread *owner) 1768 { 1769 struct lock_instance *instance; 1770 struct pcpu *pc; 1771 1772 if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU) 1773 return; 1774 pc = pcpu_find(owner->td_oncpu); 1775 instance = find_instance(pc->pc_spinlocks, lock); 1776 if (instance != NULL) 1777 witness_list_lock(instance); 1778 } 1779 1780 void 1781 witness_save(struct lock_object *lock, const char **filep, int *linep) 1782 { 1783 struct lock_instance *instance; 1784 1785 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1786 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1787 return; 1788 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1789 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1790 lock->lo_class->lc_name, lock->lo_name); 1791 instance = find_instance(curthread->td_sleeplocks, lock); 1792 if (instance == NULL) 1793 panic("%s: lock (%s) %s not locked", __func__, 1794 lock->lo_class->lc_name, lock->lo_name); 1795 *filep = instance->li_file; 1796 *linep = instance->li_line; 1797 } 1798 1799 void 1800 witness_restore(struct lock_object *lock, const char *file, int line) 1801 { 1802 struct lock_instance *instance; 1803 1804 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1805 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1806 return; 1807 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1808 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1809 lock->lo_class->lc_name, lock->lo_name); 1810 instance = find_instance(curthread->td_sleeplocks, lock); 1811 if (instance == NULL) 1812 panic("%s: lock (%s) %s not locked", __func__, 1813 lock->lo_class->lc_name, lock->lo_name); 1814 lock->lo_witness->w_file = file; 1815 lock->lo_witness->w_line = line; 1816 instance->li_file = file; 1817 instance->li_line = line; 1818 } 1819 1820 void 1821 witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1822 { 1823 #ifdef INVARIANT_SUPPORT 1824 struct lock_instance *instance; 1825 1826 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1827 return; 1828 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1829 instance = find_instance(curthread->td_sleeplocks, lock); 1830 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1831 instance = find_instance(PCPU_GET(spinlocks), lock); 1832 else { 1833 panic("Lock (%s) %s is not sleep or spin!", 1834 lock->lo_class->lc_name, lock->lo_name); 1835 } 1836 file = fixup_filename(file); 1837 switch (flags) { 1838 case LA_UNLOCKED: 1839 if (instance != NULL) 1840 panic("Lock (%s) %s locked @ %s:%d.", 1841 lock->lo_class->lc_name, lock->lo_name, file, line); 1842 break; 1843 case LA_LOCKED: 1844 case LA_LOCKED | LA_RECURSED: 1845 case LA_LOCKED | LA_NOTRECURSED: 1846 case LA_SLOCKED: 1847 case LA_SLOCKED | LA_RECURSED: 1848 case LA_SLOCKED | LA_NOTRECURSED: 1849 case LA_XLOCKED: 1850 case LA_XLOCKED | LA_RECURSED: 1851 case LA_XLOCKED | LA_NOTRECURSED: 1852 if (instance == NULL) { 1853 panic("Lock (%s) %s not locked @ %s:%d.", 1854 lock->lo_class->lc_name, lock->lo_name, file, line); 1855 break; 1856 } 1857 if ((flags & LA_XLOCKED) != 0 && 1858 (instance->li_flags & LI_EXCLUSIVE) == 0) 1859 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1860 lock->lo_class->lc_name, lock->lo_name, file, line); 1861 if ((flags & LA_SLOCKED) != 0 && 1862 (instance->li_flags & LI_EXCLUSIVE) != 0) 1863 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1864 lock->lo_class->lc_name, lock->lo_name, file, line); 1865 if ((flags & LA_RECURSED) != 0 && 1866 (instance->li_flags & LI_RECURSEMASK) == 0) 1867 panic("Lock (%s) %s not recursed @ %s:%d.", 1868 lock->lo_class->lc_name, lock->lo_name, file, line); 1869 if ((flags & LA_NOTRECURSED) != 0 && 1870 (instance->li_flags & LI_RECURSEMASK) != 0) 1871 panic("Lock (%s) %s recursed @ %s:%d.", 1872 lock->lo_class->lc_name, lock->lo_name, file, line); 1873 break; 1874 default: 1875 panic("Invalid lock assertion at %s:%d.", file, line); 1876 1877 } 1878 #endif /* INVARIANT_SUPPORT */ 1879 } 1880 1881 #ifdef DDB 1882 static void 1883 witness_list(struct thread *td) 1884 { 1885 1886 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1887 KASSERT(kdb_active, ("%s: not in the debugger", __func__)); 1888 1889 if (witness_watch == 0) 1890 return; 1891 1892 witness_list_locks(&td->td_sleeplocks); 1893 1894 /* 1895 * We only handle spinlocks if td == curthread. This is somewhat broken 1896 * if td is currently executing on some other CPU and holds spin locks 1897 * as we won't display those locks. If we had a MI way of getting 1898 * the per-cpu data for a given cpu then we could use 1899 * td->td_oncpu to get the list of spinlocks for this thread 1900 * and "fix" this. 1901 * 1902 * That still wouldn't really fix this unless we locked sched_lock 1903 * or stopped the other CPU to make sure it wasn't changing the list 1904 * out from under us. It is probably best to just not try to handle 1905 * threads on other CPU's for now. 1906 */ 1907 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1908 witness_list_locks(PCPU_PTR(spinlocks)); 1909 } 1910 1911 DB_SHOW_COMMAND(locks, db_witness_list) 1912 { 1913 struct thread *td; 1914 pid_t pid; 1915 struct proc *p; 1916 1917 if (have_addr) { 1918 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1919 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1920 ((addr >> 16) % 16) * 10000; 1921 /* sx_slock(&allproc_lock); */ 1922 FOREACH_PROC_IN_SYSTEM(p) { 1923 if (p->p_pid == pid) 1924 break; 1925 } 1926 /* sx_sunlock(&allproc_lock); */ 1927 if (p == NULL) { 1928 db_printf("pid %d not found\n", pid); 1929 return; 1930 } 1931 FOREACH_THREAD_IN_PROC(p, td) { 1932 witness_list(td); 1933 } 1934 } else { 1935 td = curthread; 1936 witness_list(td); 1937 } 1938 } 1939 1940 DB_SHOW_COMMAND(alllocks, db_witness_list_all) 1941 { 1942 struct thread *td; 1943 struct proc *p; 1944 1945 /* 1946 * It would be nice to list only threads and processes that actually 1947 * held sleep locks, but that information is currently not exported 1948 * by WITNESS. 1949 */ 1950 FOREACH_PROC_IN_SYSTEM(p) { 1951 if (!witness_proc_has_locks(p)) 1952 continue; 1953 FOREACH_THREAD_IN_PROC(p, td) { 1954 if (!witness_thread_has_locks(td)) 1955 continue; 1956 printf("Process %d (%s) thread %p (%d)\n", p->p_pid, 1957 p->p_comm, td, td->td_tid); 1958 witness_list(td); 1959 } 1960 } 1961 } 1962 1963 DB_SHOW_COMMAND(witness, db_witness_display) 1964 { 1965 1966 witness_display(db_printf); 1967 } 1968 #endif
Cache object: 6cb36304752d9e0dd97fc00e1eefb011
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