subr_witness.c revision 102448
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 * $FreeBSD: head/sys/kern/subr_witness.c 102448 2002-08-26 18:31:26Z iedowse $ 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_displaydescendants(void(*)(const char *fmt, ...), 129 struct witness *); 130static void witness_leveldescendents(struct witness *parent, int level); 131static void witness_levelall(void); 132static struct witness *witness_get(void); 133static void witness_free(struct witness *m); 134static struct witness_child_list_entry *witness_child_get(void); 135static void witness_child_free(struct witness_child_list_entry *wcl); 136static struct lock_list_entry *witness_lock_list_get(void); 137static void witness_lock_list_free(struct lock_list_entry *lle); 138static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 139 struct lock_object *lock); 140#if defined(DDB) 141static void witness_display_list(void(*prnt)(const char *fmt, ...), 142 struct witness_list *list); 143static void witness_display(void(*)(const char *fmt, ...)); 144#endif 145 146MALLOC_DEFINE(M_WITNESS, "witness", "witness structure"); 147 148static int witness_watch = 1; 149TUNABLE_INT("debug.witness_watch", &witness_watch); 150SYSCTL_INT(_debug, OID_AUTO, witness_watch, CTLFLAG_RD, &witness_watch, 0, ""); 151 152#ifdef DDB 153/* 154 * When DDB is enabled and witness_ddb is set to 1, it will cause the system to 155 * drop into kdebug() when: 156 * - a lock heirarchy violation occurs 157 * - locks are held when going to sleep. 158 */ 159#ifdef WITNESS_DDB 160int witness_ddb = 1; 161#else 162int witness_ddb = 0; 163#endif 164TUNABLE_INT("debug.witness_ddb", &witness_ddb); 165SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, ""); 166#endif /* DDB */ 167 168#ifdef WITNESS_SKIPSPIN 169int witness_skipspin = 1; 170#else 171int witness_skipspin = 0; 172#endif 173TUNABLE_INT("debug.witness_skipspin", &witness_skipspin); 174SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0, 175 ""); 176 177static struct mtx w_mtx; 178static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 179static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 180static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 181static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 182static struct witness_child_list_entry *w_child_free = NULL; 183static struct lock_list_entry *w_lock_list_free = NULL; 184static int witness_dead; /* fatal error, probably no memory */ 185 186static struct witness w_data[WITNESS_COUNT]; 187static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 188static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 189 190static struct witness_order_list_entry order_lists[] = { 191 { "Giant", &lock_class_mtx_sleep }, 192 { "proctree", &lock_class_sx }, 193 { "allproc", &lock_class_sx }, 194 { "sigio lock", &lock_class_mtx_sleep }, 195 { "process group", &lock_class_mtx_sleep }, 196 { "process lock", &lock_class_mtx_sleep }, 197 { "session", &lock_class_mtx_sleep }, 198 { "uidinfo hash", &lock_class_mtx_sleep }, 199 { "uidinfo struct", &lock_class_mtx_sleep }, 200 { NULL, NULL }, 201 /* 202 * spin locks 203 */ 204#ifdef SMP 205 { "ap boot", &lock_class_mtx_spin }, 206#ifdef __i386__ 207 { "com", &lock_class_mtx_spin }, 208#endif 209#endif 210 { "sio", &lock_class_mtx_spin }, 211#ifdef __i386__ 212 { "cy", &lock_class_mtx_spin }, 213#endif 214 { "ng_node", &lock_class_mtx_spin }, 215 { "ng_worklist", &lock_class_mtx_spin }, 216 { "ithread table lock", &lock_class_mtx_spin }, 217 { "sched lock", &lock_class_mtx_spin }, 218 { "callout", &lock_class_mtx_spin }, 219 /* 220 * leaf locks 221 */ 222 { "allpmaps", &lock_class_mtx_spin }, 223 { "vm page buckets mutex", &lock_class_mtx_spin }, 224 { "vm page queue free mutex", &lock_class_mtx_spin }, 225 { "icu", &lock_class_mtx_spin }, 226#ifdef SMP 227 { "smp rendezvous", &lock_class_mtx_spin }, 228#if defined(__i386__) && defined(APIC_IO) 229 { "tlb", &lock_class_mtx_spin }, 230#endif 231#endif 232 { "clk", &lock_class_mtx_spin }, 233 { "mutex profiling lock", &lock_class_mtx_spin }, 234 { "zombie_thread_lock", &lock_class_mtx_spin }, 235 { NULL, NULL }, 236 { NULL, NULL } 237}; 238 239/* 240 * Pairs of locks which have been blessed 241 * Don't complain about order problems with blessed locks 242 */ 243static struct witness_blessed blessed_list[] = { 244}; 245static int blessed_count = 246 sizeof(blessed_list) / sizeof(struct witness_blessed); 247 248/* 249 * List of all locks in the system. 250 */ 251TAILQ_HEAD(, lock_object) all_locks = TAILQ_HEAD_INITIALIZER(all_locks); 252 253static struct mtx all_mtx = { 254 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 255 "All locks list", /* mtx_object.lo_name */ 256 "All locks list", /* mtx_object.lo_type */ 257 LO_INITIALIZED, /* mtx_object.lo_flags */ 258 { NULL, NULL }, /* mtx_object.lo_list */ 259 NULL }, /* mtx_object.lo_witness */ 260 MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */ 261 TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked), 262 { NULL, NULL } /* mtx_contested */ 263}; 264 265/* 266 * This global is set to 0 once it becomes safe to use the witness code. 267 */ 268static int witness_cold = 1; 269 270/* 271 * Global variables for book keeping. 272 */ 273static int lock_cur_cnt; 274static int lock_max_cnt; 275 276/* 277 * The WITNESS-enabled diagnostic code. 278 */ 279static void 280witness_initialize(void *dummy __unused) 281{ 282 struct lock_object *lock; 283 struct witness_order_list_entry *order; 284 struct witness *w, *w1; 285 int i; 286 287 /* 288 * We have to release Giant before initializing its witness 289 * structure so that WITNESS doesn't get confused. 290 */ 291 mtx_unlock(&Giant); 292 mtx_assert(&Giant, MA_NOTOWNED); 293 294 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 295 TAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 296 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 297 MTX_NOWITNESS); 298 for (i = 0; i < WITNESS_COUNT; i++) 299 witness_free(&w_data[i]); 300 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 301 witness_child_free(&w_childdata[i]); 302 for (i = 0; i < LOCK_CHILDCOUNT; i++) 303 witness_lock_list_free(&w_locklistdata[i]); 304 305 /* First add in all the specified order lists. */ 306 for (order = order_lists; order->w_name != NULL; order++) { 307 w = enroll(order->w_name, order->w_class); 308 if (w == NULL) 309 continue; 310 w->w_file = "order list"; 311 for (order++; order->w_name != NULL; order++) { 312 w1 = enroll(order->w_name, order->w_class); 313 if (w1 == NULL) 314 continue; 315 w1->w_file = "order list"; 316 itismychild(w, w1); 317 w = w1; 318 } 319 } 320 321 /* Iterate through all locks and add them to witness. */ 322 mtx_lock(&all_mtx); 323 TAILQ_FOREACH(lock, &all_locks, lo_list) { 324 if (lock->lo_flags & LO_WITNESS) 325 lock->lo_witness = enroll(lock->lo_type, 326 lock->lo_class); 327 else 328 lock->lo_witness = NULL; 329 } 330 mtx_unlock(&all_mtx); 331 332 /* Mark the witness code as being ready for use. */ 333 atomic_store_rel_int(&witness_cold, 0); 334 335 mtx_lock(&Giant); 336} 337SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 338 339void 340witness_init(struct lock_object *lock) 341{ 342 struct lock_class *class; 343 344 class = lock->lo_class; 345 if (lock->lo_flags & LO_INITIALIZED) 346 panic("%s: lock (%s) %s is already initialized", __func__, 347 class->lc_name, lock->lo_name); 348 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 349 (class->lc_flags & LC_RECURSABLE) == 0) 350 panic("%s: lock (%s) %s can not be recursable", __func__, 351 class->lc_name, lock->lo_name); 352 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 353 (class->lc_flags & LC_SLEEPABLE) == 0) 354 panic("%s: lock (%s) %s can not be sleepable", __func__, 355 class->lc_name, lock->lo_name); 356 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 357 (class->lc_flags & LC_UPGRADABLE) == 0) 358 panic("%s: lock (%s) %s can not be upgradable", __func__, 359 class->lc_name, lock->lo_name); 360 361 mtx_lock(&all_mtx); 362 TAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 363 lock->lo_flags |= LO_INITIALIZED; 364 lock_cur_cnt++; 365 if (lock_cur_cnt > lock_max_cnt) 366 lock_max_cnt = lock_cur_cnt; 367 mtx_unlock(&all_mtx); 368 if (!witness_cold && !witness_dead && panicstr == NULL && 369 (lock->lo_flags & LO_WITNESS) != 0) 370 lock->lo_witness = enroll(lock->lo_type, class); 371 else 372 lock->lo_witness = NULL; 373} 374 375void 376witness_destroy(struct lock_object *lock) 377{ 378 struct witness *w; 379 380 if (witness_cold) 381 panic("lock (%s) %s destroyed while witness_cold", 382 lock->lo_class->lc_name, lock->lo_name); 383 if ((lock->lo_flags & LO_INITIALIZED) == 0) 384 panic("%s: lock (%s) %s is not initialized", __func__, 385 lock->lo_class->lc_name, lock->lo_name); 386 387 /* XXX: need to verify that no one holds the lock */ 388 w = lock->lo_witness; 389 if (w != NULL) { 390 mtx_lock_spin(&w_mtx); 391 MPASS(w->w_refcount > 0); 392 w->w_refcount--; 393 mtx_unlock_spin(&w_mtx); 394 } 395 396 mtx_lock(&all_mtx); 397 lock_cur_cnt--; 398 TAILQ_REMOVE(&all_locks, lock, lo_list); 399 lock->lo_flags &= ~LO_INITIALIZED; 400 mtx_unlock(&all_mtx); 401} 402 403#if defined(DDB) 404static void 405witness_display_list(void(*prnt)(const char *fmt, ...), 406 struct witness_list *list) 407{ 408 struct witness *w, *w1; 409 int found; 410 411 STAILQ_FOREACH(w, list, w_typelist) { 412 if (w->w_file == NULL) 413 continue; 414 found = 0; 415 STAILQ_FOREACH(w1, list, w_typelist) { 416 if (isitmychild(w1, w)) { 417 found++; 418 break; 419 } 420 } 421 if (found) 422 continue; 423 /* 424 * This lock has no anscestors, display its descendants. 425 */ 426 witness_displaydescendants(prnt, w); 427 } 428} 429 430static void 431witness_display(void(*prnt)(const char *fmt, ...)) 432{ 433 struct witness *w; 434 435 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 436 witness_levelall(); 437 438 /* 439 * First, handle sleep locks which have been acquired at least 440 * once. 441 */ 442 prnt("Sleep locks:\n"); 443 witness_display_list(prnt, &w_sleep); 444 445 /* 446 * Now do spin locks which have been acquired at least once. 447 */ 448 prnt("\nSpin locks:\n"); 449 witness_display_list(prnt, &w_spin); 450 451 /* 452 * Finally, any locks which have not been acquired yet. 453 */ 454 prnt("\nLocks which were never acquired:\n"); 455 STAILQ_FOREACH(w, &w_all, w_list) { 456 if (w->w_file != NULL || w->w_refcount == 0) 457 continue; 458 prnt("%s\n", w->w_name); 459 } 460} 461#endif 462 463void 464witness_lock(struct lock_object *lock, int flags, const char *file, int line) 465{ 466 struct lock_list_entry **lock_list, *lle; 467 struct lock_instance *lock1, *lock2; 468 struct lock_class *class; 469 struct witness *w, *w1; 470 struct thread *td; 471 int i, j; 472#ifdef DDB 473 int go_into_ddb = 0; 474#endif /* DDB */ 475 476 if (witness_cold || witness_dead || lock->lo_witness == NULL || 477 panicstr != NULL) 478 return; 479 w = lock->lo_witness; 480 class = lock->lo_class; 481 td = curthread; 482 483 if (class->lc_flags & LC_SLEEPLOCK) { 484 /* 485 * Since spin locks include a critical section, this check 486 * impliclty enforces a lock order of all sleep locks before 487 * all spin locks. 488 */ 489 if (td->td_critnest != 0 && (flags & LOP_TRYLOCK) == 0) 490 panic("blockable sleep lock (%s) %s @ %s:%d", 491 class->lc_name, lock->lo_name, file, line); 492 lock_list = &td->td_sleeplocks; 493 } else 494 lock_list = PCPU_PTR(spinlocks); 495 496 /* 497 * Try locks do not block if they fail to acquire the lock, thus 498 * there is no danger of deadlocks or of switching while holding a 499 * spin lock if we acquire a lock via a try operation. 500 */ 501 if (flags & LOP_TRYLOCK) 502 goto out; 503 504 /* 505 * Is this the first lock acquired? If so, then no order checking 506 * is needed. 507 */ 508 if (*lock_list == NULL) 509 goto out; 510 511 /* 512 * Check to see if we are recursing on a lock we already own. 513 */ 514 lock1 = find_instance(*lock_list, lock); 515 if (lock1 != NULL) { 516 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 517 (flags & LOP_EXCLUSIVE) == 0) { 518 printf("shared lock of (%s) %s @ %s:%d\n", 519 class->lc_name, lock->lo_name, file, line); 520 printf("while exclusively locked from %s:%d\n", 521 lock1->li_file, lock1->li_line); 522 panic("share->excl"); 523 } 524 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 525 (flags & LOP_EXCLUSIVE) != 0) { 526 printf("exclusive lock of (%s) %s @ %s:%d\n", 527 class->lc_name, lock->lo_name, file, line); 528 printf("while share locked from %s:%d\n", 529 lock1->li_file, lock1->li_line); 530 panic("excl->share"); 531 } 532 lock1->li_flags++; 533 if ((lock->lo_flags & LO_RECURSABLE) == 0) { 534 printf( 535 "recursed on non-recursive lock (%s) %s @ %s:%d\n", 536 class->lc_name, lock->lo_name, file, line); 537 printf("first acquired @ %s:%d\n", lock1->li_file, 538 lock1->li_line); 539 panic("recurse"); 540 } 541 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 542 td->td_proc->p_pid, lock->lo_name, 543 lock1->li_flags & LI_RECURSEMASK); 544 lock1->li_file = file; 545 lock1->li_line = line; 546 return; 547 } 548 549 /* 550 * Check for duplicate locks of the same type. Note that we only 551 * have to check for this on the last lock we just acquired. Any 552 * other cases will be caught as lock order violations. 553 */ 554 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 555 w1 = lock1->li_lock->lo_witness; 556 if (w1 == w) { 557 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK)) 558 goto out; 559 w->w_same_squawked = 1; 560 printf("acquiring duplicate lock of same type: \"%s\"\n", 561 lock->lo_type); 562 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 563 lock1->li_file, lock1->li_line); 564 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 565#ifdef DDB 566 go_into_ddb = 1; 567#endif /* DDB */ 568 goto out; 569 } 570 MPASS(!mtx_owned(&w_mtx)); 571 mtx_lock_spin(&w_mtx); 572 /* 573 * If we have a known higher number just say ok 574 */ 575 if (witness_watch > 1 && w->w_level > w1->w_level) { 576 mtx_unlock_spin(&w_mtx); 577 goto out; 578 } 579 if (isitmydescendant(w1, w)) { 580 mtx_unlock_spin(&w_mtx); 581 goto out; 582 } 583 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 584 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 585 586 MPASS(j < WITNESS_COUNT); 587 lock1 = &lle->ll_children[i]; 588 w1 = lock1->li_lock->lo_witness; 589 590 /* 591 * If this lock doesn't undergo witness checking, 592 * then skip it. 593 */ 594 if (w1 == NULL) { 595 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 596 ("lock missing witness structure")); 597 continue; 598 } 599 /* 600 * If we are locking Giant and we slept with this 601 * lock, then skip it. 602 */ 603 if ((lock1->li_flags & LI_SLEPT) != 0 && 604 lock == &Giant.mtx_object) 605 continue; 606 /* 607 * If we are locking a sleepable lock and this lock 608 * isn't sleepable and isn't Giant, we want to treat 609 * it as a lock order violation to enfore a general 610 * lock order of sleepable locks before non-sleepable 611 * locks. Thus, we only bother checking the lock 612 * order hierarchy if we pass the initial test. 613 */ 614 if (!((lock->lo_flags & LO_SLEEPABLE) != 0 && 615 ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && 616 lock1->li_lock != &Giant.mtx_object)) && 617 !isitmydescendant(w, w1)) 618 continue; 619 /* 620 * We have a lock order violation, check to see if it 621 * is allowed or has already been yelled about. 622 */ 623 mtx_unlock_spin(&w_mtx); 624 if (blessed(w, w1)) 625 goto out; 626 if (lock1->li_lock == &Giant.mtx_object) { 627 if (w1->w_Giant_squawked) 628 goto out; 629 else 630 w1->w_Giant_squawked = 1; 631 } else { 632 if (w1->w_other_squawked) 633 goto out; 634 else 635 w1->w_other_squawked = 1; 636 } 637 /* 638 * Ok, yell about it. 639 */ 640 printf("lock order reversal\n"); 641 /* 642 * Try to locate an earlier lock with 643 * witness w in our list. 644 */ 645 do { 646 lock2 = &lle->ll_children[i]; 647 MPASS(lock2->li_lock != NULL); 648 if (lock2->li_lock->lo_witness == w) 649 break; 650 i--; 651 if (i == 0 && lle->ll_next != NULL) { 652 lle = lle->ll_next; 653 i = lle->ll_count - 1; 654 MPASS(i != 0); 655 } 656 } while (i >= 0); 657 if (i < 0) { 658 printf(" 1st %p %s (%s) @ %s:%d\n", 659 lock1->li_lock, lock1->li_lock->lo_name, 660 lock1->li_lock->lo_type, lock1->li_file, 661 lock1->li_line); 662 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 663 lock->lo_name, lock->lo_type, file, line); 664 } else { 665 printf(" 1st %p %s (%s) @ %s:%d\n", 666 lock2->li_lock, lock2->li_lock->lo_name, 667 lock2->li_lock->lo_type, lock2->li_file, 668 lock2->li_line); 669 printf(" 2nd %p %s (%s) @ %s:%d\n", 670 lock1->li_lock, lock1->li_lock->lo_name, 671 lock1->li_lock->lo_type, lock1->li_file, 672 lock1->li_line); 673 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 674 lock->lo_name, lock->lo_type, file, line); 675 } 676#ifdef DDB 677 go_into_ddb = 1; 678#endif /* DDB */ 679 goto out; 680 } 681 } 682 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 683 /* 684 * Don't build a new relationship if we are locking Giant just 685 * after waking up and the previous lock in the list was acquired 686 * prior to blocking. 687 */ 688 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 689 mtx_unlock_spin(&w_mtx); 690 else { 691 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 692 lock->lo_type, lock1->li_lock->lo_type); 693 if (!itismychild(lock1->li_lock->lo_witness, w)) 694 mtx_unlock_spin(&w_mtx); 695 } 696 697out: 698#ifdef DDB 699 if (witness_ddb && go_into_ddb) 700 Debugger(__func__); 701#endif /* DDB */ 702 w->w_file = file; 703 w->w_line = line; 704 705 lle = *lock_list; 706 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 707 lle = witness_lock_list_get(); 708 if (lle == NULL) 709 return; 710 lle->ll_next = *lock_list; 711 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 712 td->td_proc->p_pid, lle); 713 *lock_list = lle; 714 } 715 lock1 = &lle->ll_children[lle->ll_count++]; 716 lock1->li_lock = lock; 717 lock1->li_line = line; 718 lock1->li_file = file; 719 if ((flags & LOP_EXCLUSIVE) != 0) 720 lock1->li_flags = LI_EXCLUSIVE; 721 else 722 lock1->li_flags = 0; 723 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 724 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 725} 726 727void 728witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 729{ 730 struct lock_instance *instance; 731 struct lock_class *class; 732 733 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 734 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 735 return; 736 class = lock->lo_class; 737 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 738 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 739 class->lc_name, lock->lo_name, file, line); 740 if ((flags & LOP_TRYLOCK) == 0) 741 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 742 lock->lo_name, file, line); 743 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 744 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 745 class->lc_name, lock->lo_name, file, line); 746 instance = find_instance(curthread->td_sleeplocks, lock); 747 if (instance == NULL) 748 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 749 class->lc_name, lock->lo_name, file, line); 750 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 751 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 752 class->lc_name, lock->lo_name, file, line); 753 if ((instance->li_flags & LI_RECURSEMASK) != 0) 754 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 755 class->lc_name, lock->lo_name, 756 instance->li_flags & LI_RECURSEMASK, file, line); 757 instance->li_flags |= LI_EXCLUSIVE; 758} 759 760void 761witness_downgrade(struct lock_object *lock, int flags, const char *file, 762 int line) 763{ 764 struct lock_instance *instance; 765 struct lock_class *class; 766 767 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 768 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 769 return; 770 class = lock->lo_class; 771 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 772 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 773 class->lc_name, lock->lo_name, file, line); 774 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 775 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 776 class->lc_name, lock->lo_name, file, line); 777 instance = find_instance(curthread->td_sleeplocks, lock); 778 if (instance == NULL) 779 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 780 class->lc_name, lock->lo_name, file, line); 781 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 782 panic("downgrade of shared lock (%s) %s @ %s:%d", 783 class->lc_name, lock->lo_name, file, line); 784 if ((instance->li_flags & LI_RECURSEMASK) != 0) 785 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 786 class->lc_name, lock->lo_name, 787 instance->li_flags & LI_RECURSEMASK, file, line); 788 instance->li_flags &= ~LI_EXCLUSIVE; 789} 790 791void 792witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 793{ 794 struct lock_list_entry **lock_list, *lle; 795 struct lock_instance *instance; 796 struct lock_class *class; 797 struct thread *td; 798 register_t s; 799 int i, j; 800 801 if (witness_cold || witness_dead || lock->lo_witness == NULL || 802 panicstr != NULL) 803 return; 804 td = curthread; 805 class = lock->lo_class; 806 if (class->lc_flags & LC_SLEEPLOCK) 807 lock_list = &td->td_sleeplocks; 808 else 809 lock_list = PCPU_PTR(spinlocks); 810 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 811 for (i = 0; i < (*lock_list)->ll_count; i++) { 812 instance = &(*lock_list)->ll_children[i]; 813 if (instance->li_lock == lock) { 814 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 815 (flags & LOP_EXCLUSIVE) == 0) { 816 printf( 817 "shared unlock of (%s) %s @ %s:%d\n", 818 class->lc_name, lock->lo_name, 819 file, line); 820 printf( 821 "while exclusively locked from %s:%d\n", 822 instance->li_file, 823 instance->li_line); 824 panic("excl->ushare"); 825 } 826 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 827 (flags & LOP_EXCLUSIVE) != 0) { 828 printf( 829 "exclusive unlock of (%s) %s @ %s:%d\n", 830 class->lc_name, lock->lo_name, 831 file, line); 832 printf( 833 "while share locked from %s:%d\n", 834 instance->li_file, 835 instance->li_line); 836 panic("share->uexcl"); 837 } 838 /* If we are recursed, unrecurse. */ 839 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 840 CTR4(KTR_WITNESS, 841 "%s: pid %d unrecursed on %s r=%d", __func__, 842 td->td_proc->p_pid, 843 instance->li_lock->lo_name, 844 instance->li_flags); 845 instance->li_flags--; 846 return; 847 } 848 s = intr_disable(); 849 CTR4(KTR_WITNESS, 850 "%s: pid %d removed %s from lle[%d]", __func__, 851 td->td_proc->p_pid, 852 instance->li_lock->lo_name, 853 (*lock_list)->ll_count - 1); 854 for (j = i; j < (*lock_list)->ll_count - 1; j++) 855 (*lock_list)->ll_children[j] = 856 (*lock_list)->ll_children[j + 1]; 857 (*lock_list)->ll_count--; 858 intr_restore(s); 859 if ((*lock_list)->ll_count == 0) { 860 lle = *lock_list; 861 *lock_list = lle->ll_next; 862 CTR3(KTR_WITNESS, 863 "%s: pid %d removed lle %p", __func__, 864 td->td_proc->p_pid, lle); 865 witness_lock_list_free(lle); 866 } 867 return; 868 } 869 } 870 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 871 file, line); 872} 873 874/* 875 * Warn if any held locks are not sleepable. Note that Giant and the lock 876 * passed in are both special cases since they are both released during the 877 * sleep process and aren't actually held while the thread is asleep. 878 */ 879int 880witness_sleep(int check_only, struct lock_object *lock, const char *file, 881 int line) 882{ 883 struct lock_list_entry **lock_list, *lle; 884 struct lock_instance *lock1; 885 struct thread *td; 886 int i, n; 887 888 if (witness_cold || witness_dead || panicstr != NULL) 889 return (0); 890 n = 0; 891 td = curthread; 892 lock_list = &td->td_sleeplocks; 893again: 894 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 895 for (i = lle->ll_count - 1; i >= 0; i--) { 896 lock1 = &lle->ll_children[i]; 897 if (lock1->li_lock == lock || 898 lock1->li_lock == &Giant.mtx_object) 899 continue; 900 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 901 if (check_only == 0) { 902 CTR3(KTR_WITNESS, 903 "pid %d: sleeping with lock (%s) %s held", 904 td->td_proc->p_pid, 905 lock1->li_lock->lo_class->lc_name, 906 lock1->li_lock->lo_name); 907 lock1->li_flags |= LI_SLEPT; 908 } 909 continue; 910 } 911 n++; 912 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 913 file, line, check_only ? "could sleep" : "sleeping", 914 lock1->li_lock->lo_name, lock1->li_file, 915 lock1->li_line); 916 } 917 if (lock_list == &td->td_sleeplocks && PCPU_GET(spinlocks) != NULL) { 918 /* 919 * Since we already hold a spinlock preemption is 920 * already blocked. 921 */ 922 lock_list = PCPU_PTR(spinlocks); 923 goto again; 924 } 925#ifdef DDB 926 if (witness_ddb && n) 927 Debugger(__func__); 928#endif /* DDB */ 929 return (n); 930} 931 932const char * 933witness_file(struct lock_object *lock) 934{ 935 struct witness *w; 936 937 if (witness_cold || witness_dead || lock->lo_witness == NULL) 938 return ("?"); 939 w = lock->lo_witness; 940 return (w->w_file); 941} 942 943int 944witness_line(struct lock_object *lock) 945{ 946 struct witness *w; 947 948 if (witness_cold || witness_dead || lock->lo_witness == NULL) 949 return (0); 950 w = lock->lo_witness; 951 return (w->w_line); 952} 953 954static struct witness * 955enroll(const char *description, struct lock_class *lock_class) 956{ 957 struct witness *w; 958 959 if (!witness_watch || witness_dead || panicstr != NULL) 960 return (NULL); 961 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 962 return (NULL); 963 mtx_lock_spin(&w_mtx); 964 STAILQ_FOREACH(w, &w_all, w_list) { 965 if (w->w_name == description || (w->w_refcount > 0 && 966 strcmp(description, w->w_name) == 0)) { 967 w->w_refcount++; 968 mtx_unlock_spin(&w_mtx); 969 if (lock_class != w->w_class) 970 panic( 971 "lock (%s) %s does not match earlier (%s) lock", 972 description, lock_class->lc_name, 973 w->w_class->lc_name); 974 return (w); 975 } 976 } 977 /* 978 * This isn't quite right, as witness_cold is still 0 while we 979 * enroll all the locks initialized before witness_initialize(). 980 */ 981 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 982 mtx_unlock_spin(&w_mtx); 983 panic("spin lock %s not in order list", description); 984 } 985 if ((w = witness_get()) == NULL) 986 return (NULL); 987 w->w_name = description; 988 w->w_class = lock_class; 989 w->w_refcount = 1; 990 STAILQ_INSERT_HEAD(&w_all, w, w_list); 991 if (lock_class->lc_flags & LC_SPINLOCK) 992 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 993 else if (lock_class->lc_flags & LC_SLEEPLOCK) 994 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 995 else { 996 mtx_unlock_spin(&w_mtx); 997 panic("lock class %s is not sleep or spin", 998 lock_class->lc_name); 999 } 1000 mtx_unlock_spin(&w_mtx); 1001 return (w); 1002} 1003 1004static int 1005itismychild(struct witness *parent, struct witness *child) 1006{ 1007 static int recursed; 1008 struct witness_child_list_entry **wcl; 1009 struct witness_list *list; 1010 1011 MPASS(child != NULL && parent != NULL); 1012 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 1013 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 1014 panic( 1015 "%s: parent (%s) and child (%s) are not the same lock type", 1016 __func__, parent->w_class->lc_name, 1017 child->w_class->lc_name); 1018 1019 /* 1020 * Insert "child" after "parent" 1021 */ 1022 wcl = &parent->w_children; 1023 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1024 wcl = &(*wcl)->wcl_next; 1025 if (*wcl == NULL) { 1026 *wcl = witness_child_get(); 1027 if (*wcl == NULL) 1028 return (1); 1029 } 1030 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1031 1032 /* 1033 * Now prune whole tree. We look for cases where a lock is now 1034 * both a descendant and a direct child of a given lock. In that 1035 * case, we want to remove the direct child link from the tree. 1036 */ 1037 if (recursed) 1038 return (0); 1039 recursed = 1; 1040 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1041 list = &w_sleep; 1042 else 1043 list = &w_spin; 1044 STAILQ_FOREACH(child, list, w_typelist) { 1045 STAILQ_FOREACH(parent, list, w_typelist) { 1046 if (!isitmychild(parent, child)) 1047 continue; 1048 removechild(parent, child); 1049 if (isitmydescendant(parent, child)) 1050 continue; 1051 itismychild(parent, child); 1052 } 1053 } 1054 recursed = 0; 1055 witness_levelall(); 1056 return (0); 1057} 1058 1059static void 1060removechild(struct witness *parent, struct witness *child) 1061{ 1062 struct witness_child_list_entry **wcl, *wcl1; 1063 int i; 1064 1065 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1066 for (i = 0; i < (*wcl)->wcl_count; i++) 1067 if ((*wcl)->wcl_children[i] == child) 1068 goto found; 1069 return; 1070found: 1071 (*wcl)->wcl_count--; 1072 if ((*wcl)->wcl_count > i) 1073 (*wcl)->wcl_children[i] = 1074 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1075 MPASS((*wcl)->wcl_children[i] != NULL); 1076 if ((*wcl)->wcl_count != 0) 1077 return; 1078 wcl1 = *wcl; 1079 *wcl = wcl1->wcl_next; 1080 witness_child_free(wcl1); 1081} 1082 1083static int 1084isitmychild(struct witness *parent, struct witness *child) 1085{ 1086 struct witness_child_list_entry *wcl; 1087 int i; 1088 1089 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1090 for (i = 0; i < wcl->wcl_count; i++) { 1091 if (wcl->wcl_children[i] == child) 1092 return (1); 1093 } 1094 } 1095 return (0); 1096} 1097 1098static int 1099isitmydescendant(struct witness *parent, struct witness *child) 1100{ 1101 struct witness_child_list_entry *wcl; 1102 int i, j; 1103 1104 if (isitmychild(parent, child)) 1105 return (1); 1106 j = 0; 1107 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1108 MPASS(j < 1000); 1109 for (i = 0; i < wcl->wcl_count; i++) { 1110 if (isitmydescendant(wcl->wcl_children[i], child)) 1111 return (1); 1112 } 1113 j++; 1114 } 1115 return (0); 1116} 1117 1118void 1119witness_levelall (void) 1120{ 1121 struct witness_list *list; 1122 struct witness *w, *w1; 1123 1124 /* 1125 * First clear all levels. 1126 */ 1127 STAILQ_FOREACH(w, &w_all, w_list) { 1128 w->w_level = 0; 1129 } 1130 1131 /* 1132 * Look for locks with no parent and level all their descendants. 1133 */ 1134 STAILQ_FOREACH(w, &w_all, w_list) { 1135 /* 1136 * This is just an optimization, technically we could get 1137 * away just walking the all list each time. 1138 */ 1139 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1140 list = &w_sleep; 1141 else 1142 list = &w_spin; 1143 STAILQ_FOREACH(w1, list, w_typelist) { 1144 if (isitmychild(w1, w)) 1145 goto skip; 1146 } 1147 witness_leveldescendents(w, 0); 1148 skip: 1149 ; /* silence GCC 3.x */ 1150 } 1151} 1152 1153static void 1154witness_leveldescendents(struct witness *parent, int level) 1155{ 1156 struct witness_child_list_entry *wcl; 1157 int i; 1158 1159 if (parent->w_level < level) 1160 parent->w_level = level; 1161 level++; 1162 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1163 for (i = 0; i < wcl->wcl_count; i++) 1164 witness_leveldescendents(wcl->wcl_children[i], level); 1165} 1166 1167static void 1168witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1169 struct witness *parent) 1170{ 1171 struct witness_child_list_entry *wcl; 1172 int i, level; 1173 1174 level = parent->w_level; 1175 prnt("%-2d", level); 1176 for (i = 0; i < level; i++) 1177 prnt(" "); 1178 if (parent->w_refcount > 0) { 1179 prnt("%s", parent->w_name); 1180 if (parent->w_file != NULL) 1181 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1182 parent->w_line); 1183 } else 1184 prnt("(dead)\n"); 1185 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1186 for (i = 0; i < wcl->wcl_count; i++) 1187 witness_displaydescendants(prnt, 1188 wcl->wcl_children[i]); 1189} 1190 1191static int 1192blessed(struct witness *w1, struct witness *w2) 1193{ 1194 int i; 1195 struct witness_blessed *b; 1196 1197 for (i = 0; i < blessed_count; i++) { 1198 b = &blessed_list[i]; 1199 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1200 if (strcmp(w2->w_name, b->b_lock2) == 0) 1201 return (1); 1202 continue; 1203 } 1204 if (strcmp(w1->w_name, b->b_lock2) == 0) 1205 if (strcmp(w2->w_name, b->b_lock1) == 0) 1206 return (1); 1207 } 1208 return (0); 1209} 1210 1211static struct witness * 1212witness_get(void) 1213{ 1214 struct witness *w; 1215 1216 if (witness_dead) { 1217 mtx_unlock_spin(&w_mtx); 1218 return (NULL); 1219 } 1220 if (STAILQ_EMPTY(&w_free)) { 1221 witness_dead = 1; 1222 mtx_unlock_spin(&w_mtx); 1223 printf("%s: witness exhausted\n", __func__); 1224 return (NULL); 1225 } 1226 w = STAILQ_FIRST(&w_free); 1227 STAILQ_REMOVE_HEAD(&w_free, w_list); 1228 bzero(w, sizeof(*w)); 1229 return (w); 1230} 1231 1232static void 1233witness_free(struct witness *w) 1234{ 1235 1236 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1237} 1238 1239static struct witness_child_list_entry * 1240witness_child_get(void) 1241{ 1242 struct witness_child_list_entry *wcl; 1243 1244 if (witness_dead) { 1245 mtx_unlock_spin(&w_mtx); 1246 return (NULL); 1247 } 1248 wcl = w_child_free; 1249 if (wcl == NULL) { 1250 witness_dead = 1; 1251 mtx_unlock_spin(&w_mtx); 1252 printf("%s: witness exhausted\n", __func__); 1253 return (NULL); 1254 } 1255 w_child_free = wcl->wcl_next; 1256 bzero(wcl, sizeof(*wcl)); 1257 return (wcl); 1258} 1259 1260static void 1261witness_child_free(struct witness_child_list_entry *wcl) 1262{ 1263 1264 wcl->wcl_next = w_child_free; 1265 w_child_free = wcl; 1266} 1267 1268static struct lock_list_entry * 1269witness_lock_list_get(void) 1270{ 1271 struct lock_list_entry *lle; 1272 1273 if (witness_dead) 1274 return (NULL); 1275 mtx_lock_spin(&w_mtx); 1276 lle = w_lock_list_free; 1277 if (lle == NULL) { 1278 witness_dead = 1; 1279 mtx_unlock_spin(&w_mtx); 1280 printf("%s: witness exhausted\n", __func__); 1281 return (NULL); 1282 } 1283 w_lock_list_free = lle->ll_next; 1284 mtx_unlock_spin(&w_mtx); 1285 bzero(lle, sizeof(*lle)); 1286 return (lle); 1287} 1288 1289static void 1290witness_lock_list_free(struct lock_list_entry *lle) 1291{ 1292 1293 mtx_lock_spin(&w_mtx); 1294 lle->ll_next = w_lock_list_free; 1295 w_lock_list_free = lle; 1296 mtx_unlock_spin(&w_mtx); 1297} 1298 1299static struct lock_instance * 1300find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1301{ 1302 struct lock_list_entry *lle; 1303 struct lock_instance *instance; 1304 int i; 1305 1306 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1307 for (i = lle->ll_count - 1; i >= 0; i--) { 1308 instance = &lle->ll_children[i]; 1309 if (instance->li_lock == lock) 1310 return (instance); 1311 } 1312 return (NULL); 1313} 1314 1315int 1316witness_list_locks(struct lock_list_entry **lock_list) 1317{ 1318 struct lock_list_entry *lle; 1319 struct lock_instance *instance; 1320 struct lock_object *lock; 1321 int i, nheld; 1322 1323 nheld = 0; 1324 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1325 for (i = lle->ll_count - 1; i >= 0; i--) { 1326 instance = &lle->ll_children[i]; 1327 lock = instance->li_lock; 1328 printf("%s %s %s", 1329 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1330 "exclusive" : "shared", 1331 lock->lo_class->lc_name, lock->lo_name); 1332 if (lock->lo_type != lock->lo_name) 1333 printf(" (%s)", lock->lo_type); 1334 printf(" r = %d (%p) locked @ %s:%d\n", 1335 instance->li_flags & LI_RECURSEMASK, lock, 1336 instance->li_file, instance->li_line); 1337 nheld++; 1338 } 1339 return (nheld); 1340} 1341 1342/* 1343 * Calling this on td != curthread is bad unless we are in ddb. 1344 */ 1345int 1346witness_list(struct thread *td) 1347{ 1348 int nheld; 1349 1350 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1351#ifdef DDB 1352 KASSERT(td == curthread || db_active, 1353 ("%s: td != curthread and we aren't in the debugger", __func__)); 1354 if (!db_active && witness_dead) 1355 return (0); 1356#else 1357 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1358 if (witness_dead) 1359 return (0); 1360#endif 1361 nheld = witness_list_locks(&td->td_sleeplocks); 1362 1363 /* 1364 * We only handle spinlocks if td == curthread. This is somewhat broken 1365 * if td is currently executing on some other CPU and holds spin locks 1366 * as we won't display those locks. If we had a MI way of getting 1367 * the per-cpu data for a given cpu then we could use 1368 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1369 * and "fix" this. 1370 * 1371 * That still wouldn't really fix this unless we locked sched_lock 1372 * or stopped the other CPU to make sure it wasn't changing the list 1373 * out from under us. It is probably best to just not try to handle 1374 * threads on other CPU's for now. 1375 */ 1376 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1377 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1378 1379 return (nheld); 1380} 1381 1382void 1383witness_save(struct lock_object *lock, const char **filep, int *linep) 1384{ 1385 struct lock_instance *instance; 1386 1387 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1388 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1389 return; 1390 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1391 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1392 lock->lo_class->lc_name, lock->lo_name); 1393 instance = find_instance(curthread->td_sleeplocks, lock); 1394 if (instance == NULL) 1395 panic("%s: lock (%s) %s not locked", __func__, 1396 lock->lo_class->lc_name, lock->lo_name); 1397 *filep = instance->li_file; 1398 *linep = instance->li_line; 1399} 1400 1401void 1402witness_restore(struct lock_object *lock, const char *file, int line) 1403{ 1404 struct lock_instance *instance; 1405 1406 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1407 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1408 return; 1409 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1410 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1411 lock->lo_class->lc_name, lock->lo_name); 1412 instance = find_instance(curthread->td_sleeplocks, lock); 1413 if (instance == NULL) 1414 panic("%s: lock (%s) %s not locked", __func__, 1415 lock->lo_class->lc_name, lock->lo_name); 1416 lock->lo_witness->w_file = file; 1417 lock->lo_witness->w_line = line; 1418 instance->li_file = file; 1419 instance->li_line = line; 1420} 1421 1422void 1423witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1424{ 1425#ifdef INVARIANT_SUPPORT 1426 struct lock_instance *instance; 1427 1428 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1429 return; 1430 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1431 instance = find_instance(curthread->td_sleeplocks, lock); 1432 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1433 instance = find_instance(PCPU_GET(spinlocks), lock); 1434 else { 1435 panic("Lock (%s) %s is not sleep or spin!", 1436 lock->lo_class->lc_name, lock->lo_name); 1437 return; 1438 } 1439 switch (flags) { 1440 case LA_UNLOCKED: 1441 if (instance != NULL) 1442 panic("Lock (%s) %s locked @ %s:%d.", 1443 lock->lo_class->lc_name, lock->lo_name, file, line); 1444 break; 1445 case LA_LOCKED: 1446 case LA_LOCKED | LA_RECURSED: 1447 case LA_LOCKED | LA_NOTRECURSED: 1448 case LA_SLOCKED: 1449 case LA_SLOCKED | LA_RECURSED: 1450 case LA_SLOCKED | LA_NOTRECURSED: 1451 case LA_XLOCKED: 1452 case LA_XLOCKED | LA_RECURSED: 1453 case LA_XLOCKED | LA_NOTRECURSED: 1454 if (instance == NULL) { 1455 panic("Lock (%s) %s not locked @ %s:%d.", 1456 lock->lo_class->lc_name, lock->lo_name, file, line); 1457 break; 1458 } 1459 if ((flags & LA_XLOCKED) != 0 && 1460 (instance->li_flags & LI_EXCLUSIVE) == 0) 1461 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1462 lock->lo_class->lc_name, lock->lo_name, file, line); 1463 if ((flags & LA_SLOCKED) != 0 && 1464 (instance->li_flags & LI_EXCLUSIVE) != 0) 1465 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1466 lock->lo_class->lc_name, lock->lo_name, file, line); 1467 if ((flags & LA_RECURSED) != 0 && 1468 (instance->li_flags & LI_RECURSEMASK) == 0) 1469 panic("Lock (%s) %s not recursed @ %s:%d.", 1470 lock->lo_class->lc_name, lock->lo_name, file, line); 1471 if ((flags & LA_NOTRECURSED) != 0 && 1472 (instance->li_flags & LI_RECURSEMASK) != 0) 1473 panic("Lock (%s) %s recursed @ %s:%d.", 1474 lock->lo_class->lc_name, lock->lo_name, file, line); 1475 break; 1476 default: 1477 panic("Invalid lock assertion at %s:%d.", file, line); 1478 1479 } 1480#endif /* INVARIANT_SUPPORT */ 1481} 1482 1483#ifdef DDB 1484 1485DB_SHOW_COMMAND(locks, db_witness_list) 1486{ 1487 struct thread *td; 1488 pid_t pid; 1489 struct proc *p; 1490 1491 if (have_addr) { 1492 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1493 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1494 ((addr >> 16) % 16) * 10000; 1495 /* sx_slock(&allproc_lock); */ 1496 FOREACH_PROC_IN_SYSTEM(p) { 1497 if (p->p_pid == pid) 1498 break; 1499 } 1500 /* sx_sunlock(&allproc_lock); */ 1501 if (p == NULL) { 1502 db_printf("pid %d not found\n", pid); 1503 return; 1504 } 1505 FOREACH_THREAD_IN_PROC(p, td) { 1506 witness_list(td); 1507 } 1508 } else { 1509 td = curthread; 1510 witness_list(td); 1511 } 1512} 1513 1514DB_SHOW_COMMAND(witness, db_witness_display) 1515{ 1516 1517 witness_display(db_printf); 1518} 1519#endif 1520