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