subr_witness.c revision 99862
1280849Scy/*- 2280849Scy * Copyright (c) 1998 Berkeley Software Design, Inc. All rights reserved. 3280849Scy * 4280849Scy * Redistribution and use in source and binary forms, with or without 554359Sroberto * modification, are permitted provided that the following conditions 654359Sroberto * are met: 7280849Scy * 1. Redistributions of source code must retain the above copyright 8316722Sdelphij * notice, this list of conditions and the following disclaimer. 9316722Sdelphij * 2. Redistributions in binary form must reproduce the above copyright 10280849Scy * notice, this list of conditions and the following disclaimer in the 11280849Scy * documentation and/or other materials provided with the distribution. 12280849Scy * 3. Berkeley Software Design Inc's name may not be used to endorse or 13316722Sdelphij * promote products derived from this software without specific prior 14280849Scy * written permission. 15316722Sdelphij * 16316722Sdelphij * THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND 17280849Scy * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18280849Scy * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 1954359Sroberto * ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE 2082498Sroberto * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2154359Sroberto * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22132451Sroberto * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23132451Sroberto * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24132451Sroberto * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25132451Sroberto * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26280849Scy * SUCH DAMAGE. 27280849Scy * 28280849Scy * 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 * $FreeBSD: head/sys/kern/subr_witness.c 99862 2002-07-12 07:56:11Z peter $ 31 */ 32 33/* 34 * Implementation of the `witness' lock verifier. Originally implemented for 35 * mutexes in BSD/OS. Extended to handle generic lock objects and lock 36 * classes in FreeBSD. 37 */ 38 39/* 40 * Main Entry: witness 41 * Pronunciation: 'wit-n&s 42 * Function: noun 43 * Etymology: Middle English witnesse, from Old English witnes knowledge, 44 * testimony, witness, from 2wit 45 * Date: before 12th century 46 * 1 : attestation of a fact or event : TESTIMONY 47 * 2 : one that gives evidence; specifically : one who testifies in 48 * a cause or before a judicial tribunal 49 * 3 : one asked to be present at a transaction so as to be able to 50 * testify to its having taken place 51 * 4 : one who has personal knowledge of something 52 * 5 a : something serving as evidence or proof : SIGN 53 * b : public affirmation by word or example of usually 54 * religious faith or conviction <the heroic witness to divine 55 * life -- Pilot> 56 * 6 capitalized : a member of the Jehovah's Witnesses 57 */ 58 59#include "opt_ddb.h" 60#include "opt_witness.h" 61 62#include <sys/param.h> 63#include <sys/bus.h> 64#include <sys/kernel.h> 65#include <sys/ktr.h> 66#include <sys/lock.h> 67#include <sys/malloc.h> 68#include <sys/mutex.h> 69#include <sys/proc.h> 70#include <sys/sysctl.h> 71#include <sys/systm.h> 72 73#include <ddb/ddb.h> 74 75#define WITNESS_COUNT 200 76#define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4) 77/* 78 * XXX: This is somewhat bogus, as we assume here that at most 1024 threads 79 * will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should 80 * probably be safe for the most part, but it's still a SWAG. 81 */ 82#define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2 83 84#define WITNESS_NCHILDREN 6 85 86struct witness_child_list_entry; 87 88struct witness { 89 const char *w_name; 90 struct lock_class *w_class; 91 STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */ 92 STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ 93 struct witness_child_list_entry *w_children; /* Great evilness... */ 94 const char *w_file; 95 int w_line; 96 u_int w_level; 97 u_int w_refcount; 98 u_char w_Giant_squawked:1; 99 u_char w_other_squawked:1; 100 u_char w_same_squawked:1; 101}; 102 103struct witness_child_list_entry { 104 struct witness_child_list_entry *wcl_next; 105 struct witness *wcl_children[WITNESS_NCHILDREN]; 106 u_int wcl_count; 107}; 108 109STAILQ_HEAD(witness_list, witness); 110 111struct witness_blessed { 112 const char *b_lock1; 113 const char *b_lock2; 114}; 115 116struct witness_order_list_entry { 117 const char *w_name; 118 struct lock_class *w_class; 119}; 120 121static struct witness *enroll(const char *description, 122 struct lock_class *lock_class); 123static int itismychild(struct witness *parent, struct witness *child); 124static void removechild(struct witness *parent, struct witness *child); 125static int isitmychild(struct witness *parent, struct witness *child); 126static int isitmydescendant(struct witness *parent, struct witness *child); 127static int blessed(struct witness *, struct witness *); 128static void witness_display_list(void(*prnt)(const char *fmt, ...), 129 struct witness_list *list); 130static void witness_displaydescendants(void(*)(const char *fmt, ...), 131 struct witness *); 132static void witness_leveldescendents(struct witness *parent, int level); 133static void witness_levelall(void); 134static struct witness *witness_get(void); 135static void witness_free(struct witness *m); 136static struct witness_child_list_entry *witness_child_get(void); 137static void witness_child_free(struct witness_child_list_entry *wcl); 138static struct lock_list_entry *witness_lock_list_get(void); 139static void witness_lock_list_free(struct lock_list_entry *lle); 140static void witness_display(void(*)(const char *fmt, ...)); 141static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 142 struct lock_object *lock); 143 144MALLOC_DEFINE(M_WITNESS, "witness", "witness structure"); 145 146static int witness_watch = 1; 147TUNABLE_INT("debug.witness_watch", &witness_watch); 148SYSCTL_INT(_debug, OID_AUTO, witness_watch, CTLFLAG_RD, &witness_watch, 0, ""); 149 150#ifdef DDB 151/* 152 * When DDB is enabled and witness_ddb is set to 1, it will cause the system to 153 * drop into kdebug() when: 154 * - a lock heirarchy violation occurs 155 * - locks are held when going to sleep. 156 */ 157#ifdef WITNESS_DDB 158int witness_ddb = 1; 159#else 160int witness_ddb = 0; 161#endif 162TUNABLE_INT("debug.witness_ddb", &witness_ddb); 163SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, ""); 164#endif /* DDB */ 165 166#ifdef WITNESS_SKIPSPIN 167int witness_skipspin = 1; 168#else 169int witness_skipspin = 0; 170#endif 171TUNABLE_INT("debug.witness_skipspin", &witness_skipspin); 172SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0, 173 ""); 174 175static struct mtx w_mtx; 176static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 177static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 178static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 179static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 180static struct witness_child_list_entry *w_child_free = NULL; 181static struct lock_list_entry *w_lock_list_free = NULL; 182static int witness_dead; /* fatal error, probably no memory */ 183 184static struct witness w_data[WITNESS_COUNT]; 185static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 186static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 187 188static struct witness_order_list_entry order_lists[] = { 189 { "Giant", &lock_class_mtx_sleep }, 190 { "proctree", &lock_class_sx }, 191 { "allproc", &lock_class_sx }, 192 { "sigio lock", &lock_class_mtx_sleep }, 193 { "process group", &lock_class_mtx_sleep }, 194 { "process lock", &lock_class_mtx_sleep }, 195 { "session", &lock_class_mtx_sleep }, 196 { "uidinfo hash", &lock_class_mtx_sleep }, 197 { "uidinfo struct", &lock_class_mtx_sleep }, 198 { NULL, NULL }, 199 /* 200 * spin locks 201 */ 202#ifdef SMP 203 { "ap boot", &lock_class_mtx_spin }, 204#ifdef __i386__ 205 { "com", &lock_class_mtx_spin }, 206#endif 207#endif 208 { "sio", &lock_class_mtx_spin }, 209#ifdef __i386__ 210 { "cy", &lock_class_mtx_spin }, 211#endif 212 { "ng_node", &lock_class_mtx_spin }, 213 { "ng_worklist", &lock_class_mtx_spin }, 214 { "ithread table lock", &lock_class_mtx_spin }, 215 { "sched lock", &lock_class_mtx_spin }, 216 { "callout", &lock_class_mtx_spin }, 217 /* 218 * leaf locks 219 */ 220 { "allpmaps", &lock_class_mtx_spin }, 221 { "vm page buckets mutex", &lock_class_mtx_spin }, 222 { "vm page queue free mutex", &lock_class_mtx_spin }, 223 { "icu", &lock_class_mtx_spin }, 224#ifdef SMP 225 { "smp rendezvous", &lock_class_mtx_spin }, 226#if defined(__i386__) && defined(APIC_IO) 227 { "tlb", &lock_class_mtx_spin }, 228#endif 229#endif 230 { "clk", &lock_class_mtx_spin }, 231 { "mutex profiling lock", &lock_class_mtx_spin }, 232 { "zombie_thread_lock", &lock_class_mtx_spin }, 233 { NULL, NULL }, 234 { NULL, NULL } 235}; 236 237/* 238 * Pairs of locks which have been blessed 239 * Don't complain about order problems with blessed locks 240 */ 241static struct witness_blessed blessed_list[] = { 242}; 243static int blessed_count = 244 sizeof(blessed_list) / sizeof(struct witness_blessed); 245 246/* 247 * List of all locks in the system. 248 */ 249TAILQ_HEAD(, lock_object) all_locks = TAILQ_HEAD_INITIALIZER(all_locks); 250 251static struct mtx all_mtx = { 252 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 253 "All locks list", /* mtx_object.lo_name */ 254 "All locks list", /* mtx_object.lo_type */ 255 LO_INITIALIZED, /* mtx_object.lo_flags */ 256 { NULL, NULL }, /* mtx_object.lo_list */ 257 NULL }, /* mtx_object.lo_witness */ 258 MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */ 259 TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked), 260 { NULL, NULL } /* mtx_contested */ 261}; 262 263/* 264 * This global is set to 0 once it becomes safe to use the witness code. 265 */ 266static int witness_cold = 1; 267 268/* 269 * Global variables for book keeping. 270 */ 271static int lock_cur_cnt; 272static int lock_max_cnt; 273 274/* 275 * The WITNESS-enabled diagnostic code. 276 */ 277static void 278witness_initialize(void *dummy __unused) 279{ 280 struct lock_object *lock; 281 struct witness_order_list_entry *order; 282 struct witness *w, *w1; 283 int i; 284 285 /* 286 * We have to release Giant before initializing its witness 287 * structure so that WITNESS doesn't get confused. 288 */ 289 mtx_unlock(&Giant); 290 mtx_assert(&Giant, MA_NOTOWNED); 291 292 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 293 TAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 294 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 295 MTX_NOWITNESS); 296 for (i = 0; i < WITNESS_COUNT; i++) 297 witness_free(&w_data[i]); 298 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 299 witness_child_free(&w_childdata[i]); 300 for (i = 0; i < LOCK_CHILDCOUNT; i++) 301 witness_lock_list_free(&w_locklistdata[i]); 302 303 /* First add in all the specified order lists. */ 304 for (order = order_lists; order->w_name != NULL; order++) { 305 w = enroll(order->w_name, order->w_class); 306 if (w == NULL) 307 continue; 308 w->w_file = "order list"; 309 for (order++; order->w_name != NULL; order++) { 310 w1 = enroll(order->w_name, order->w_class); 311 if (w1 == NULL) 312 continue; 313 w1->w_file = "order list"; 314 itismychild(w, w1); 315 w = w1; 316 } 317 } 318 319 /* Iterate through all locks and add them to witness. */ 320 mtx_lock(&all_mtx); 321 TAILQ_FOREACH(lock, &all_locks, lo_list) { 322 if (lock->lo_flags & LO_WITNESS) 323 lock->lo_witness = enroll(lock->lo_type, 324 lock->lo_class); 325 else 326 lock->lo_witness = NULL; 327 } 328 mtx_unlock(&all_mtx); 329 330 /* Mark the witness code as being ready for use. */ 331 atomic_store_rel_int(&witness_cold, 0); 332 333 mtx_lock(&Giant); 334} 335SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 336 337void 338witness_init(struct lock_object *lock) 339{ 340 struct lock_class *class; 341 342 class = lock->lo_class; 343 if (lock->lo_flags & LO_INITIALIZED) 344 panic("%s: lock (%s) %s is already initialized", __func__, 345 class->lc_name, lock->lo_name); 346 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 347 (class->lc_flags & LC_RECURSABLE) == 0) 348 panic("%s: lock (%s) %s can not be recursable", __func__, 349 class->lc_name, lock->lo_name); 350 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 351 (class->lc_flags & LC_SLEEPABLE) == 0) 352 panic("%s: lock (%s) %s can not be sleepable", __func__, 353 class->lc_name, lock->lo_name); 354 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 355 (class->lc_flags & LC_UPGRADABLE) == 0) 356 panic("%s: lock (%s) %s can not be upgradable", __func__, 357 class->lc_name, lock->lo_name); 358 359 mtx_lock(&all_mtx); 360 TAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 361 lock->lo_flags |= LO_INITIALIZED; 362 lock_cur_cnt++; 363 if (lock_cur_cnt > lock_max_cnt) 364 lock_max_cnt = lock_cur_cnt; 365 mtx_unlock(&all_mtx); 366 if (!witness_cold && !witness_dead && panicstr == NULL && 367 (lock->lo_flags & LO_WITNESS) != 0) 368 lock->lo_witness = enroll(lock->lo_type, class); 369 else 370 lock->lo_witness = NULL; 371} 372 373void 374witness_destroy(struct lock_object *lock) 375{ 376 struct witness *w; 377 378 if (witness_cold) 379 panic("lock (%s) %s destroyed while witness_cold", 380 lock->lo_class->lc_name, lock->lo_name); 381 if ((lock->lo_flags & LO_INITIALIZED) == 0) 382 panic("%s: lock (%s) %s is not initialized", __func__, 383 lock->lo_class->lc_name, lock->lo_name); 384 385 /* XXX: need to verify that no one holds the lock */ 386 w = lock->lo_witness; 387 if (w != NULL) { 388 mtx_lock_spin(&w_mtx); 389 MPASS(w->w_refcount > 0); 390 w->w_refcount--; 391 mtx_unlock_spin(&w_mtx); 392 } 393 394 mtx_lock(&all_mtx); 395 lock_cur_cnt--; 396 TAILQ_REMOVE(&all_locks, lock, lo_list); 397 lock->lo_flags &= ~LO_INITIALIZED; 398 mtx_unlock(&all_mtx); 399} 400 401static void 402witness_display_list(void(*prnt)(const char *fmt, ...), 403 struct witness_list *list) 404{ 405 struct witness *w, *w1; 406 int found; 407 408 STAILQ_FOREACH(w, list, w_typelist) { 409 if (w->w_file == NULL) 410 continue; 411 found = 0; 412 STAILQ_FOREACH(w1, list, w_typelist) { 413 if (isitmychild(w1, w)) { 414 found++; 415 break; 416 } 417 } 418 if (found) 419 continue; 420 /* 421 * This lock has no anscestors, display its descendants. 422 */ 423 witness_displaydescendants(prnt, w); 424 } 425} 426 427static void 428witness_display(void(*prnt)(const char *fmt, ...)) 429{ 430 struct witness *w; 431 432 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 433 witness_levelall(); 434 435 /* 436 * First, handle sleep locks which have been acquired at least 437 * once. 438 */ 439 prnt("Sleep locks:\n"); 440 witness_display_list(prnt, &w_sleep); 441 442 /* 443 * Now do spin locks which have been acquired at least once. 444 */ 445 prnt("\nSpin locks:\n"); 446 witness_display_list(prnt, &w_spin); 447 448 /* 449 * Finally, any locks which have not been acquired yet. 450 */ 451 prnt("\nLocks which were never acquired:\n"); 452 STAILQ_FOREACH(w, &w_all, w_list) { 453 if (w->w_file != NULL || w->w_refcount == 0) 454 continue; 455 prnt("%s\n", w->w_name); 456 } 457} 458 459void 460witness_lock(struct lock_object *lock, int flags, const char *file, int line) 461{ 462 struct lock_list_entry **lock_list, *lle; 463 struct lock_instance *lock1, *lock2; 464 struct lock_class *class; 465 struct witness *w, *w1; 466 struct thread *td; 467 int i, j; 468#ifdef DDB 469 int go_into_ddb = 0; 470#endif /* DDB */ 471 472 if (witness_cold || witness_dead || lock->lo_witness == NULL || 473 panicstr != NULL) 474 return; 475 w = lock->lo_witness; 476 class = lock->lo_class; 477 td = curthread; 478 479 if (class->lc_flags & LC_SLEEPLOCK) { 480 /* 481 * Since spin locks include a critical section, this check 482 * impliclty enforces a lock order of all sleep locks before 483 * all spin locks. 484 */ 485 if (td->td_critnest != 0 && (flags & LOP_TRYLOCK) == 0) 486 panic("blockable sleep lock (%s) %s @ %s:%d", 487 class->lc_name, lock->lo_name, file, line); 488 lock_list = &td->td_sleeplocks; 489 } else 490 lock_list = PCPU_PTR(spinlocks); 491 492 /* 493 * Try locks do not block if they fail to acquire the lock, thus 494 * there is no danger of deadlocks or of switching while holding a 495 * spin lock if we acquire a lock via a try operation. 496 */ 497 if (flags & LOP_TRYLOCK) 498 goto out; 499 500 /* 501 * Is this the first lock acquired? If so, then no order checking 502 * is needed. 503 */ 504 if (*lock_list == NULL) 505 goto out; 506 507 /* 508 * Check to see if we are recursing on a lock we already own. 509 */ 510 lock1 = find_instance(*lock_list, lock); 511 if (lock1 != NULL) { 512 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 513 (flags & LOP_EXCLUSIVE) == 0) { 514 printf("shared lock of (%s) %s @ %s:%d\n", 515 class->lc_name, lock->lo_name, file, line); 516 printf("while exclusively locked from %s:%d\n", 517 lock1->li_file, lock1->li_line); 518 panic("share->excl"); 519 } 520 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 521 (flags & LOP_EXCLUSIVE) != 0) { 522 printf("exclusive lock of (%s) %s @ %s:%d\n", 523 class->lc_name, lock->lo_name, file, line); 524 printf("while share locked from %s:%d\n", 525 lock1->li_file, lock1->li_line); 526 panic("excl->share"); 527 } 528 lock1->li_flags++; 529 if ((lock->lo_flags & LO_RECURSABLE) == 0) { 530 printf( 531 "recursed on non-recursive lock (%s) %s @ %s:%d\n", 532 class->lc_name, lock->lo_name, file, line); 533 printf("first acquired @ %s:%d\n", lock1->li_file, 534 lock1->li_line); 535 panic("recurse"); 536 } 537 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 538 td->td_proc->p_pid, lock->lo_name, 539 lock1->li_flags & LI_RECURSEMASK); 540 lock1->li_file = file; 541 lock1->li_line = line; 542 return; 543 } 544 545 /* 546 * Check for duplicate locks of the same type. Note that we only 547 * have to check for this on the last lock we just acquired. Any 548 * other cases will be caught as lock order violations. 549 */ 550 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 551 w1 = lock1->li_lock->lo_witness; 552 if (w1 == w) { 553 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK)) 554 goto out; 555 w->w_same_squawked = 1; 556 printf("acquiring duplicate lock of same type: \"%s\"\n", 557 lock->lo_type); 558 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 559 lock1->li_file, lock1->li_line); 560 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 561#ifdef DDB 562 go_into_ddb = 1; 563#endif /* DDB */ 564 goto out; 565 } 566 MPASS(!mtx_owned(&w_mtx)); 567 mtx_lock_spin(&w_mtx); 568 /* 569 * If we have a known higher number just say ok 570 */ 571 if (witness_watch > 1 && w->w_level > w1->w_level) { 572 mtx_unlock_spin(&w_mtx); 573 goto out; 574 } 575 if (isitmydescendant(w1, w)) { 576 mtx_unlock_spin(&w_mtx); 577 goto out; 578 } 579 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 580 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 581 582 MPASS(j < WITNESS_COUNT); 583 lock1 = &lle->ll_children[i]; 584 w1 = lock1->li_lock->lo_witness; 585 586 /* 587 * If this lock doesn't undergo witness checking, 588 * then skip it. 589 */ 590 if (w1 == NULL) { 591 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 592 ("lock missing witness structure")); 593 continue; 594 } 595 /* 596 * If we are locking Giant and we slept with this 597 * lock, then skip it. 598 */ 599 if ((lock1->li_flags & LI_SLEPT) != 0 && 600 lock == &Giant.mtx_object) 601 continue; 602 /* 603 * If we are locking a sleepable lock and this lock 604 * isn't sleepable and isn't Giant, we want to treat 605 * it as a lock order violation to enfore a general 606 * lock order of sleepable locks before non-sleepable 607 * locks. Thus, we only bother checking the lock 608 * order hierarchy if we pass the initial test. 609 */ 610 if (!((lock->lo_flags & LO_SLEEPABLE) != 0 && 611 ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && 612 lock1->li_lock != &Giant.mtx_object)) && 613 !isitmydescendant(w, w1)) 614 continue; 615 /* 616 * We have a lock order violation, check to see if it 617 * is allowed or has already been yelled about. 618 */ 619 mtx_unlock_spin(&w_mtx); 620 if (blessed(w, w1)) 621 goto out; 622 if (lock1->li_lock == &Giant.mtx_object) { 623 if (w1->w_Giant_squawked) 624 goto out; 625 else 626 w1->w_Giant_squawked = 1; 627 } else { 628 if (w1->w_other_squawked) 629 goto out; 630 else 631 w1->w_other_squawked = 1; 632 } 633 /* 634 * Ok, yell about it. 635 */ 636 printf("lock order reversal\n"); 637 /* 638 * Try to locate an earlier lock with 639 * witness w in our list. 640 */ 641 do { 642 lock2 = &lle->ll_children[i]; 643 MPASS(lock2->li_lock != NULL); 644 if (lock2->li_lock->lo_witness == w) 645 break; 646 i--; 647 if (i == 0 && lle->ll_next != NULL) { 648 lle = lle->ll_next; 649 i = lle->ll_count - 1; 650 MPASS(i != 0); 651 } 652 } while (i >= 0); 653 if (i < 0) { 654 printf(" 1st %p %s (%s) @ %s:%d\n", 655 lock1->li_lock, lock1->li_lock->lo_name, 656 lock1->li_lock->lo_type, lock1->li_file, 657 lock1->li_line); 658 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 659 lock->lo_name, lock->lo_type, file, line); 660 } else { 661 printf(" 1st %p %s (%s) @ %s:%d\n", 662 lock2->li_lock, lock2->li_lock->lo_name, 663 lock2->li_lock->lo_type, lock2->li_file, 664 lock2->li_line); 665 printf(" 2nd %p %s (%s) @ %s:%d\n", 666 lock1->li_lock, lock1->li_lock->lo_name, 667 lock1->li_lock->lo_type, lock1->li_file, 668 lock1->li_line); 669 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 670 lock->lo_name, lock->lo_type, file, line); 671 } 672#ifdef DDB 673 go_into_ddb = 1; 674#endif /* DDB */ 675 goto out; 676 } 677 } 678 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 679 /* 680 * Don't build a new relationship if we are locking Giant just 681 * after waking up and the previous lock in the list was acquired 682 * prior to blocking. 683 */ 684 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 685 mtx_unlock_spin(&w_mtx); 686 else { 687 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 688 lock->lo_type, lock1->li_lock->lo_type); 689 if (!itismychild(lock1->li_lock->lo_witness, w)) 690 mtx_unlock_spin(&w_mtx); 691 } 692 693out: 694#ifdef DDB 695 if (witness_ddb && go_into_ddb) 696 Debugger(__func__); 697#endif /* DDB */ 698 w->w_file = file; 699 w->w_line = line; 700 701 lle = *lock_list; 702 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 703 lle = witness_lock_list_get(); 704 if (lle == NULL) 705 return; 706 lle->ll_next = *lock_list; 707 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 708 td->td_proc->p_pid, lle); 709 *lock_list = lle; 710 } 711 lock1 = &lle->ll_children[lle->ll_count++]; 712 lock1->li_lock = lock; 713 lock1->li_line = line; 714 lock1->li_file = file; 715 if ((flags & LOP_EXCLUSIVE) != 0) 716 lock1->li_flags = LI_EXCLUSIVE; 717 else 718 lock1->li_flags = 0; 719 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 720 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 721} 722 723void 724witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 725{ 726 struct lock_instance *instance; 727 struct lock_class *class; 728 729 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 730 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 731 return; 732 class = lock->lo_class; 733 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 734 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 735 class->lc_name, lock->lo_name, file, line); 736 if ((flags & LOP_TRYLOCK) == 0) 737 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 738 lock->lo_name, file, line); 739 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 740 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 741 class->lc_name, lock->lo_name, file, line); 742 instance = find_instance(curthread->td_sleeplocks, lock); 743 if (instance == NULL) 744 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 745 class->lc_name, lock->lo_name, file, line); 746 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 747 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 748 class->lc_name, lock->lo_name, file, line); 749 if ((instance->li_flags & LI_RECURSEMASK) != 0) 750 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 751 class->lc_name, lock->lo_name, 752 instance->li_flags & LI_RECURSEMASK, file, line); 753 instance->li_flags |= LI_EXCLUSIVE; 754} 755 756void 757witness_downgrade(struct lock_object *lock, int flags, const char *file, 758 int line) 759{ 760 struct lock_instance *instance; 761 struct lock_class *class; 762 763 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 764 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 765 return; 766 class = lock->lo_class; 767 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 768 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 769 class->lc_name, lock->lo_name, file, line); 770 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 771 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 772 class->lc_name, lock->lo_name, file, line); 773 instance = find_instance(curthread->td_sleeplocks, lock); 774 if (instance == NULL) 775 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 776 class->lc_name, lock->lo_name, file, line); 777 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 778 panic("downgrade of shared lock (%s) %s @ %s:%d", 779 class->lc_name, lock->lo_name, file, line); 780 if ((instance->li_flags & LI_RECURSEMASK) != 0) 781 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 782 class->lc_name, lock->lo_name, 783 instance->li_flags & LI_RECURSEMASK, file, line); 784 instance->li_flags &= ~LI_EXCLUSIVE; 785} 786 787void 788witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 789{ 790 struct lock_list_entry **lock_list, *lle; 791 struct lock_instance *instance; 792 struct lock_class *class; 793 struct thread *td; 794 register_t s; 795 int i, j; 796 797 if (witness_cold || witness_dead || lock->lo_witness == NULL || 798 panicstr != NULL) 799 return; 800 td = curthread; 801 class = lock->lo_class; 802 if (class->lc_flags & LC_SLEEPLOCK) 803 lock_list = &td->td_sleeplocks; 804 else 805 lock_list = PCPU_PTR(spinlocks); 806 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 807 for (i = 0; i < (*lock_list)->ll_count; i++) { 808 instance = &(*lock_list)->ll_children[i]; 809 if (instance->li_lock == lock) { 810 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 811 (flags & LOP_EXCLUSIVE) == 0) { 812 printf( 813 "shared unlock of (%s) %s @ %s:%d\n", 814 class->lc_name, lock->lo_name, 815 file, line); 816 printf( 817 "while exclusively locked from %s:%d\n", 818 instance->li_file, 819 instance->li_line); 820 panic("excl->ushare"); 821 } 822 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 823 (flags & LOP_EXCLUSIVE) != 0) { 824 printf( 825 "exclusive unlock of (%s) %s @ %s:%d\n", 826 class->lc_name, lock->lo_name, 827 file, line); 828 printf( 829 "while share locked from %s:%d\n", 830 instance->li_file, 831 instance->li_line); 832 panic("share->uexcl"); 833 } 834 /* If we are recursed, unrecurse. */ 835 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 836 CTR4(KTR_WITNESS, 837 "%s: pid %d unrecursed on %s r=%d", __func__, 838 td->td_proc->p_pid, 839 instance->li_lock->lo_name, 840 instance->li_flags); 841 instance->li_flags--; 842 return; 843 } 844 s = intr_disable(); 845 CTR4(KTR_WITNESS, 846 "%s: pid %d removed %s from lle[%d]", __func__, 847 td->td_proc->p_pid, 848 instance->li_lock->lo_name, 849 (*lock_list)->ll_count - 1); 850 for (j = i; j < (*lock_list)->ll_count - 1; j++) 851 (*lock_list)->ll_children[j] = 852 (*lock_list)->ll_children[j + 1]; 853 (*lock_list)->ll_count--; 854 intr_restore(s); 855 if ((*lock_list)->ll_count == 0) { 856 lle = *lock_list; 857 *lock_list = lle->ll_next; 858 CTR3(KTR_WITNESS, 859 "%s: pid %d removed lle %p", __func__, 860 td->td_proc->p_pid, lle); 861 witness_lock_list_free(lle); 862 } 863 return; 864 } 865 } 866 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 867 file, line); 868} 869 870/* 871 * Warn if any held locks are not sleepable. Note that Giant and the lock 872 * passed in are both special cases since they are both released during the 873 * sleep process and aren't actually held while the thread is asleep. 874 */ 875int 876witness_sleep(int check_only, struct lock_object *lock, const char *file, 877 int line) 878{ 879 struct lock_list_entry **lock_list, *lle; 880 struct lock_instance *lock1; 881 struct thread *td; 882 int i, n; 883 884 if (witness_cold || witness_dead || panicstr != NULL) 885 return (0); 886 n = 0; 887 td = curthread; 888 lock_list = &td->td_sleeplocks; 889again: 890 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 891 for (i = lle->ll_count - 1; i >= 0; i--) { 892 lock1 = &lle->ll_children[i]; 893 if (lock1->li_lock == lock || 894 lock1->li_lock == &Giant.mtx_object) 895 continue; 896 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 897 if (check_only == 0) { 898 CTR3(KTR_WITNESS, 899 "pid %d: sleeping with lock (%s) %s held", 900 td->td_proc->p_pid, 901 lock1->li_lock->lo_class->lc_name, 902 lock1->li_lock->lo_name); 903 lock1->li_flags |= LI_SLEPT; 904 } 905 continue; 906 } 907 n++; 908 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 909 file, line, check_only ? "could sleep" : "sleeping", 910 lock1->li_lock->lo_name, lock1->li_file, 911 lock1->li_line); 912 } 913 if (lock_list == &td->td_sleeplocks && PCPU_GET(spinlocks) != NULL) { 914 /* 915 * Since we already hold a spinlock preemption is 916 * already blocked. 917 */ 918 lock_list = PCPU_PTR(spinlocks); 919 goto again; 920 } 921#ifdef DDB 922 if (witness_ddb && n) 923 Debugger(__func__); 924#endif /* DDB */ 925 return (n); 926} 927 928static struct witness * 929enroll(const char *description, struct lock_class *lock_class) 930{ 931 struct witness *w; 932 933 if (!witness_watch || witness_dead || panicstr != NULL) 934 return (NULL); 935 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 936 return (NULL); 937 mtx_lock_spin(&w_mtx); 938 STAILQ_FOREACH(w, &w_all, w_list) { 939 if (w->w_name == description || (w->w_refcount > 0 && 940 strcmp(description, w->w_name) == 0)) { 941 w->w_refcount++; 942 mtx_unlock_spin(&w_mtx); 943 if (lock_class != w->w_class) 944 panic( 945 "lock (%s) %s does not match earlier (%s) lock", 946 description, lock_class->lc_name, 947 w->w_class->lc_name); 948 return (w); 949 } 950 } 951 /* 952 * This isn't quite right, as witness_cold is still 0 while we 953 * enroll all the locks initialized before witness_initialize(). 954 */ 955 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 956 mtx_unlock_spin(&w_mtx); 957 panic("spin lock %s not in order list", description); 958 } 959 if ((w = witness_get()) == NULL) 960 return (NULL); 961 w->w_name = description; 962 w->w_class = lock_class; 963 w->w_refcount = 1; 964 STAILQ_INSERT_HEAD(&w_all, w, w_list); 965 if (lock_class->lc_flags & LC_SPINLOCK) 966 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 967 else if (lock_class->lc_flags & LC_SLEEPLOCK) 968 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 969 else { 970 mtx_unlock_spin(&w_mtx); 971 panic("lock class %s is not sleep or spin", 972 lock_class->lc_name); 973 } 974 mtx_unlock_spin(&w_mtx); 975 return (w); 976} 977 978static int 979itismychild(struct witness *parent, struct witness *child) 980{ 981 static int recursed; 982 struct witness_child_list_entry **wcl; 983 struct witness_list *list; 984 985 MPASS(child != NULL && parent != NULL); 986 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 987 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 988 panic( 989 "%s: parent (%s) and child (%s) are not the same lock type", 990 __func__, parent->w_class->lc_name, 991 child->w_class->lc_name); 992 993 /* 994 * Insert "child" after "parent" 995 */ 996 wcl = &parent->w_children; 997 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 998 wcl = &(*wcl)->wcl_next; 999 if (*wcl == NULL) { 1000 *wcl = witness_child_get(); 1001 if (*wcl == NULL) 1002 return (1); 1003 } 1004 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1005 1006 /* 1007 * Now prune whole tree. We look for cases where a lock is now 1008 * both a descendant and a direct child of a given lock. In that 1009 * case, we want to remove the direct child link from the tree. 1010 */ 1011 if (recursed) 1012 return (0); 1013 recursed = 1; 1014 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1015 list = &w_sleep; 1016 else 1017 list = &w_spin; 1018 STAILQ_FOREACH(child, list, w_typelist) { 1019 STAILQ_FOREACH(parent, list, w_typelist) { 1020 if (!isitmychild(parent, child)) 1021 continue; 1022 removechild(parent, child); 1023 if (isitmydescendant(parent, child)) 1024 continue; 1025 itismychild(parent, child); 1026 } 1027 } 1028 recursed = 0; 1029 witness_levelall(); 1030 return (0); 1031} 1032 1033static void 1034removechild(struct witness *parent, struct witness *child) 1035{ 1036 struct witness_child_list_entry **wcl, *wcl1; 1037 int i; 1038 1039 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1040 for (i = 0; i < (*wcl)->wcl_count; i++) 1041 if ((*wcl)->wcl_children[i] == child) 1042 goto found; 1043 return; 1044found: 1045 (*wcl)->wcl_count--; 1046 if ((*wcl)->wcl_count > i) 1047 (*wcl)->wcl_children[i] = 1048 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1049 MPASS((*wcl)->wcl_children[i] != NULL); 1050 if ((*wcl)->wcl_count != 0) 1051 return; 1052 wcl1 = *wcl; 1053 *wcl = wcl1->wcl_next; 1054 witness_child_free(wcl1); 1055} 1056 1057static int 1058isitmychild(struct witness *parent, struct witness *child) 1059{ 1060 struct witness_child_list_entry *wcl; 1061 int i; 1062 1063 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1064 for (i = 0; i < wcl->wcl_count; i++) { 1065 if (wcl->wcl_children[i] == child) 1066 return (1); 1067 } 1068 } 1069 return (0); 1070} 1071 1072static int 1073isitmydescendant(struct witness *parent, struct witness *child) 1074{ 1075 struct witness_child_list_entry *wcl; 1076 int i, j; 1077 1078 if (isitmychild(parent, child)) 1079 return (1); 1080 j = 0; 1081 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1082 MPASS(j < 1000); 1083 for (i = 0; i < wcl->wcl_count; i++) { 1084 if (isitmydescendant(wcl->wcl_children[i], child)) 1085 return (1); 1086 } 1087 j++; 1088 } 1089 return (0); 1090} 1091 1092void 1093witness_levelall (void) 1094{ 1095 struct witness_list *list; 1096 struct witness *w, *w1; 1097 1098 /* 1099 * First clear all levels. 1100 */ 1101 STAILQ_FOREACH(w, &w_all, w_list) { 1102 w->w_level = 0; 1103 } 1104 1105 /* 1106 * Look for locks with no parent and level all their descendants. 1107 */ 1108 STAILQ_FOREACH(w, &w_all, w_list) { 1109 /* 1110 * This is just an optimization, technically we could get 1111 * away just walking the all list each time. 1112 */ 1113 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1114 list = &w_sleep; 1115 else 1116 list = &w_spin; 1117 STAILQ_FOREACH(w1, list, w_typelist) { 1118 if (isitmychild(w1, w)) 1119 goto skip; 1120 } 1121 witness_leveldescendents(w, 0); 1122 skip: 1123 ; /* silence GCC 3.x */ 1124 } 1125} 1126 1127static void 1128witness_leveldescendents(struct witness *parent, int level) 1129{ 1130 struct witness_child_list_entry *wcl; 1131 int i; 1132 1133 if (parent->w_level < level) 1134 parent->w_level = level; 1135 level++; 1136 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1137 for (i = 0; i < wcl->wcl_count; i++) 1138 witness_leveldescendents(wcl->wcl_children[i], level); 1139} 1140 1141static void 1142witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1143 struct witness *parent) 1144{ 1145 struct witness_child_list_entry *wcl; 1146 int i, level; 1147 1148 level = parent->w_level; 1149 prnt("%-2d", level); 1150 for (i = 0; i < level; i++) 1151 prnt(" "); 1152 if (parent->w_refcount > 0) { 1153 prnt("%s", parent->w_name); 1154 if (parent->w_file != NULL) 1155 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1156 parent->w_line); 1157 } else 1158 prnt("(dead)\n"); 1159 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1160 for (i = 0; i < wcl->wcl_count; i++) 1161 witness_displaydescendants(prnt, 1162 wcl->wcl_children[i]); 1163} 1164 1165static int 1166blessed(struct witness *w1, struct witness *w2) 1167{ 1168 int i; 1169 struct witness_blessed *b; 1170 1171 for (i = 0; i < blessed_count; i++) { 1172 b = &blessed_list[i]; 1173 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1174 if (strcmp(w2->w_name, b->b_lock2) == 0) 1175 return (1); 1176 continue; 1177 } 1178 if (strcmp(w1->w_name, b->b_lock2) == 0) 1179 if (strcmp(w2->w_name, b->b_lock1) == 0) 1180 return (1); 1181 } 1182 return (0); 1183} 1184 1185static struct witness * 1186witness_get(void) 1187{ 1188 struct witness *w; 1189 1190 if (witness_dead) { 1191 mtx_unlock_spin(&w_mtx); 1192 return (NULL); 1193 } 1194 if (STAILQ_EMPTY(&w_free)) { 1195 witness_dead = 1; 1196 mtx_unlock_spin(&w_mtx); 1197 printf("%s: witness exhausted\n", __func__); 1198 return (NULL); 1199 } 1200 w = STAILQ_FIRST(&w_free); 1201 STAILQ_REMOVE_HEAD(&w_free, w_list); 1202 bzero(w, sizeof(*w)); 1203 return (w); 1204} 1205 1206static void 1207witness_free(struct witness *w) 1208{ 1209 1210 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1211} 1212 1213static struct witness_child_list_entry * 1214witness_child_get(void) 1215{ 1216 struct witness_child_list_entry *wcl; 1217 1218 if (witness_dead) { 1219 mtx_unlock_spin(&w_mtx); 1220 return (NULL); 1221 } 1222 wcl = w_child_free; 1223 if (wcl == NULL) { 1224 witness_dead = 1; 1225 mtx_unlock_spin(&w_mtx); 1226 printf("%s: witness exhausted\n", __func__); 1227 return (NULL); 1228 } 1229 w_child_free = wcl->wcl_next; 1230 bzero(wcl, sizeof(*wcl)); 1231 return (wcl); 1232} 1233 1234static void 1235witness_child_free(struct witness_child_list_entry *wcl) 1236{ 1237 1238 wcl->wcl_next = w_child_free; 1239 w_child_free = wcl; 1240} 1241 1242static struct lock_list_entry * 1243witness_lock_list_get(void) 1244{ 1245 struct lock_list_entry *lle; 1246 1247 if (witness_dead) 1248 return (NULL); 1249 mtx_lock_spin(&w_mtx); 1250 lle = w_lock_list_free; 1251 if (lle == NULL) { 1252 witness_dead = 1; 1253 mtx_unlock_spin(&w_mtx); 1254 printf("%s: witness exhausted\n", __func__); 1255 return (NULL); 1256 } 1257 w_lock_list_free = lle->ll_next; 1258 mtx_unlock_spin(&w_mtx); 1259 bzero(lle, sizeof(*lle)); 1260 return (lle); 1261} 1262 1263static void 1264witness_lock_list_free(struct lock_list_entry *lle) 1265{ 1266 1267 mtx_lock_spin(&w_mtx); 1268 lle->ll_next = w_lock_list_free; 1269 w_lock_list_free = lle; 1270 mtx_unlock_spin(&w_mtx); 1271} 1272 1273static struct lock_instance * 1274find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1275{ 1276 struct lock_list_entry *lle; 1277 struct lock_instance *instance; 1278 int i; 1279 1280 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1281 for (i = lle->ll_count - 1; i >= 0; i--) { 1282 instance = &lle->ll_children[i]; 1283 if (instance->li_lock == lock) 1284 return (instance); 1285 } 1286 return (NULL); 1287} 1288 1289int 1290witness_list_locks(struct lock_list_entry **lock_list) 1291{ 1292 struct lock_list_entry *lle; 1293 struct lock_instance *instance; 1294 struct lock_object *lock; 1295 int i, nheld; 1296 1297 nheld = 0; 1298 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1299 for (i = lle->ll_count - 1; i >= 0; i--) { 1300 instance = &lle->ll_children[i]; 1301 lock = instance->li_lock; 1302 printf("%s %s %s", 1303 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1304 "exclusive" : "shared", 1305 lock->lo_class->lc_name, lock->lo_name); 1306 if (lock->lo_type != lock->lo_name) 1307 printf(" (%s)", lock->lo_type); 1308 printf(" r = %d (%p) locked @ %s:%d\n", 1309 instance->li_flags & LI_RECURSEMASK, lock, 1310 instance->li_file, instance->li_line); 1311 nheld++; 1312 } 1313 return (nheld); 1314} 1315 1316/* 1317 * Calling this on td != curthread is bad unless we are in ddb. 1318 */ 1319int 1320witness_list(struct thread *td) 1321{ 1322 int nheld; 1323 1324 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1325#ifdef DDB 1326 KASSERT(td == curthread || db_active, 1327 ("%s: td != curthread and we aren't in the debugger", __func__)); 1328 if (!db_active && witness_dead) 1329 return (0); 1330#else 1331 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1332 if (witness_dead) 1333 return (0); 1334#endif 1335 nheld = witness_list_locks(&td->td_sleeplocks); 1336 1337 /* 1338 * We only handle spinlocks if td == curthread. This is somewhat broken 1339 * if td is currently executing on some other CPU and holds spin locks 1340 * as we won't display those locks. If we had a MI way of getting 1341 * the per-cpu data for a given cpu then we could use 1342 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1343 * and "fix" this. 1344 * 1345 * That still wouldn't really fix this unless we locked sched_lock 1346 * or stopped the other CPU to make sure it wasn't changing the list 1347 * out from under us. It is probably best to just not try to handle 1348 * threads on other CPU's for now. 1349 */ 1350 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1351 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1352 1353 return (nheld); 1354} 1355 1356void 1357witness_save(struct lock_object *lock, const char **filep, int *linep) 1358{ 1359 struct lock_instance *instance; 1360 1361 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1362 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1363 return; 1364 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1365 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1366 lock->lo_class->lc_name, lock->lo_name); 1367 instance = find_instance(curthread->td_sleeplocks, lock); 1368 if (instance == NULL) 1369 panic("%s: lock (%s) %s not locked", __func__, 1370 lock->lo_class->lc_name, lock->lo_name); 1371 *filep = instance->li_file; 1372 *linep = instance->li_line; 1373} 1374 1375void 1376witness_restore(struct lock_object *lock, const char *file, int line) 1377{ 1378 struct lock_instance *instance; 1379 1380 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1381 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1382 return; 1383 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1384 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1385 lock->lo_class->lc_name, lock->lo_name); 1386 instance = find_instance(curthread->td_sleeplocks, lock); 1387 if (instance == NULL) 1388 panic("%s: lock (%s) %s not locked", __func__, 1389 lock->lo_class->lc_name, lock->lo_name); 1390 lock->lo_witness->w_file = file; 1391 lock->lo_witness->w_line = line; 1392 instance->li_file = file; 1393 instance->li_line = line; 1394} 1395 1396void 1397witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1398{ 1399#ifdef INVARIANT_SUPPORT 1400 struct lock_instance *instance; 1401 1402 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1403 return; 1404 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1405 instance = find_instance(curthread->td_sleeplocks, lock); 1406 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1407 instance = find_instance(PCPU_GET(spinlocks), lock); 1408 else { 1409 panic("Lock (%s) %s is not sleep or spin!", 1410 lock->lo_class->lc_name, lock->lo_name); 1411 return; 1412 } 1413 switch (flags) { 1414 case LA_UNLOCKED: 1415 if (instance != NULL) 1416 panic("Lock (%s) %s locked @ %s:%d.", 1417 lock->lo_class->lc_name, lock->lo_name, file, line); 1418 break; 1419 case LA_LOCKED: 1420 case LA_LOCKED | LA_RECURSED: 1421 case LA_LOCKED | LA_NOTRECURSED: 1422 case LA_SLOCKED: 1423 case LA_SLOCKED | LA_RECURSED: 1424 case LA_SLOCKED | LA_NOTRECURSED: 1425 case LA_XLOCKED: 1426 case LA_XLOCKED | LA_RECURSED: 1427 case LA_XLOCKED | LA_NOTRECURSED: 1428 if (instance == NULL) { 1429 panic("Lock (%s) %s not locked @ %s:%d.", 1430 lock->lo_class->lc_name, lock->lo_name, file, line); 1431 break; 1432 } 1433 if ((flags & LA_XLOCKED) != 0 && 1434 (instance->li_flags & LI_EXCLUSIVE) == 0) 1435 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1436 lock->lo_class->lc_name, lock->lo_name, file, line); 1437 if ((flags & LA_SLOCKED) != 0 && 1438 (instance->li_flags & LI_EXCLUSIVE) != 0) 1439 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1440 lock->lo_class->lc_name, lock->lo_name, file, line); 1441 if ((flags & LA_RECURSED) != 0 && 1442 (instance->li_flags & LI_RECURSEMASK) == 0) 1443 panic("Lock (%s) %s not recursed @ %s:%d.", 1444 lock->lo_class->lc_name, lock->lo_name, file, line); 1445 if ((flags & LA_NOTRECURSED) != 0 && 1446 (instance->li_flags & LI_RECURSEMASK) != 0) 1447 panic("Lock (%s) %s recursed @ %s:%d.", 1448 lock->lo_class->lc_name, lock->lo_name, file, line); 1449 break; 1450 default: 1451 panic("Invalid lock assertion at %s:%d.", file, line); 1452 1453 } 1454#endif /* INVARIANT_SUPPORT */ 1455} 1456 1457#ifdef DDB 1458 1459DB_SHOW_COMMAND(locks, db_witness_list) 1460{ 1461 struct thread *td; 1462 pid_t pid; 1463 struct proc *p; 1464 1465 if (have_addr) { 1466 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1467 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1468 ((addr >> 16) % 16) * 10000; 1469 /* sx_slock(&allproc_lock); */ 1470 FOREACH_PROC_IN_SYSTEM(p) { 1471 if (p->p_pid == pid) 1472 break; 1473 } 1474 /* sx_sunlock(&allproc_lock); */ 1475 if (p == NULL) { 1476 db_printf("pid %d not found\n", pid); 1477 return; 1478 } 1479 FOREACH_THREAD_IN_PROC(p, td) { 1480 witness_list(td); 1481 } 1482 } else { 1483 td = curthread; 1484 witness_list(td); 1485 } 1486} 1487 1488DB_SHOW_COMMAND(witness, db_witness_display) 1489{ 1490 1491 witness_display(db_printf); 1492} 1493#endif 1494