subr_witness.c revision 93811
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 93811 2002-04-04 20:45:21Z jhb $ 31 */ 32 33/* 34 * Implementation of the `witness' lock verifier. Originally implemented for 35 * mutexes in BSD/OS. Extended to handle generic lock objects and lock 36 * classes in FreeBSD. 37 */ 38 39/* 40 * Main Entry: witness 41 * Pronunciation: 'wit-n&s 42 * Function: noun 43 * Etymology: Middle English witnesse, from Old English witnes knowledge, 44 * testimony, witness, from 2wit 45 * Date: before 12th century 46 * 1 : attestation of a fact or event : TESTIMONY 47 * 2 : one that gives evidence; specifically : one who testifies in 48 * a cause or before a judicial tribunal 49 * 3 : one asked to be present at a transaction so as to be able to 50 * testify to its having taken place 51 * 4 : one who has personal knowledge of something 52 * 5 a : something serving as evidence or proof : SIGN 53 * b : public affirmation by word or example of usually 54 * religious faith or conviction <the heroic witness to divine 55 * life -- Pilot> 56 * 6 capitalized : a member of the Jehovah's Witnesses 57 */ 58 59#include "opt_ddb.h" 60#include "opt_witness.h" 61 62#include <sys/param.h> 63#include <sys/bus.h> 64#include <sys/kernel.h> 65#include <sys/ktr.h> 66#include <sys/lock.h> 67#include <sys/malloc.h> 68#include <sys/mutex.h> 69#include <sys/proc.h> 70#include <sys/sysctl.h> 71#include <sys/systm.h> 72 73#include <ddb/ddb.h> 74 75#define WITNESS_COUNT 200 76#define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4) 77/* 78 * XXX: This is somewhat bogus, as we assume here that at most 1024 threads 79 * will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should 80 * probably be safe for the most part, but it's still a SWAG. 81 */ 82#define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2 83 84#define WITNESS_NCHILDREN 6 85 86struct witness_child_list_entry; 87 88struct witness { 89 const char *w_name; 90 struct lock_class *w_class; 91 STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */ 92 STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ 93 struct witness_child_list_entry *w_children; /* Great evilness... */ 94 const char *w_file; 95 int w_line; 96 u_int w_level; 97 u_int w_refcount; 98 u_char w_Giant_squawked:1; 99 u_char w_other_squawked:1; 100 u_char w_same_squawked:1; 101}; 102 103struct witness_child_list_entry { 104 struct witness_child_list_entry *wcl_next; 105 struct witness *wcl_children[WITNESS_NCHILDREN]; 106 u_int wcl_count; 107}; 108 109STAILQ_HEAD(witness_list, witness); 110 111struct witness_blessed { 112 const char *b_lock1; 113 const char *b_lock2; 114}; 115 116struct witness_order_list_entry { 117 const char *w_name; 118 struct lock_class *w_class; 119}; 120 121static struct witness *enroll(const char *description, 122 struct lock_class *lock_class); 123static int itismychild(struct witness *parent, struct witness *child); 124static void removechild(struct witness *parent, struct witness *child); 125static int isitmychild(struct witness *parent, struct witness *child); 126static int isitmydescendant(struct witness *parent, struct witness *child); 127static int blessed(struct witness *, struct witness *); 128static void witness_display_list(void(*prnt)(const char *fmt, ...), 129 struct witness_list *list); 130static void witness_displaydescendants(void(*)(const char *fmt, ...), 131 struct witness *); 132static void witness_leveldescendents(struct witness *parent, int level); 133static void witness_levelall(void); 134static struct witness *witness_get(void); 135static void witness_free(struct witness *m); 136static struct witness_child_list_entry *witness_child_get(void); 137static void witness_child_free(struct witness_child_list_entry *wcl); 138static struct lock_list_entry *witness_lock_list_get(void); 139static void witness_lock_list_free(struct lock_list_entry *lle); 140static void witness_display(void(*)(const char *fmt, ...)); 141static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 142 struct lock_object *lock); 143 144MALLOC_DEFINE(M_WITNESS, "witness", "witness structure"); 145 146static int witness_watch = 1; 147TUNABLE_INT("debug.witness_watch", &witness_watch); 148SYSCTL_INT(_debug, OID_AUTO, witness_watch, CTLFLAG_RD, &witness_watch, 0, ""); 149 150#ifdef DDB 151/* 152 * When DDB is enabled and witness_ddb is set to 1, it will cause the system to 153 * drop into kdebug() when: 154 * - a lock heirarchy violation occurs 155 * - locks are held when going to sleep. 156 */ 157#ifdef WITNESS_DDB 158int witness_ddb = 1; 159#else 160int witness_ddb = 0; 161#endif 162TUNABLE_INT("debug.witness_ddb", &witness_ddb); 163SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, ""); 164#endif /* DDB */ 165 166#ifdef WITNESS_SKIPSPIN 167int witness_skipspin = 1; 168#else 169int witness_skipspin = 0; 170#endif 171TUNABLE_INT("debug.witness_skipspin", &witness_skipspin); 172SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0, 173 ""); 174 175static struct mtx w_mtx; 176static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 177static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 178static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 179static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 180static struct witness_child_list_entry *w_child_free = NULL; 181static struct lock_list_entry *w_lock_list_free = NULL; 182static int witness_dead; /* fatal error, probably no memory */ 183 184static struct witness w_data[WITNESS_COUNT]; 185static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 186static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 187 188static struct witness_order_list_entry order_lists[] = { 189 { "Giant", &lock_class_mtx_sleep }, 190 { "pgrpsess", &lock_class_sx }, 191 { "proctree", &lock_class_sx }, 192 { "allproc", &lock_class_sx }, 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 { "icu", &lock_class_mtx_spin }, 222#ifdef SMP 223 { "smp rendezvous", &lock_class_mtx_spin }, 224#endif 225 { "clk", &lock_class_mtx_spin }, 226 { NULL, NULL }, 227 { NULL, NULL } 228}; 229 230/* 231 * Pairs of locks which have been blessed 232 * Don't complain about order problems with blessed locks 233 */ 234static struct witness_blessed blessed_list[] = { 235}; 236static int blessed_count = 237 sizeof(blessed_list) / sizeof(struct witness_blessed); 238 239/* 240 * List of all locks in the system. 241 */ 242STAILQ_HEAD(, lock_object) all_locks = STAILQ_HEAD_INITIALIZER(all_locks); 243 244static struct mtx all_mtx = { 245 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 246 "All locks list", /* mtx_object.lo_name */ 247 "All locks list", /* mtx_object.lo_type */ 248 LO_INITIALIZED, /* mtx_object.lo_flags */ 249 { NULL }, /* mtx_object.lo_list */ 250 NULL }, /* mtx_object.lo_witness */ 251 MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */ 252 TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked), 253 { NULL, NULL } /* mtx_contested */ 254}; 255 256/* 257 * This global is set to 0 once it becomes safe to use the witness code. 258 */ 259static int witness_cold = 1; 260 261/* 262 * Global variables for book keeping. 263 */ 264static int lock_cur_cnt; 265static int lock_max_cnt; 266 267/* 268 * The WITNESS-enabled diagnostic code. 269 */ 270static void 271witness_initialize(void *dummy __unused) 272{ 273 struct lock_object *lock; 274 struct witness_order_list_entry *order; 275 struct witness *w, *w1; 276 int i; 277 278 /* 279 * We have to release Giant before initializing its witness 280 * structure so that WITNESS doesn't get confused. 281 */ 282 mtx_unlock(&Giant); 283 mtx_assert(&Giant, MA_NOTOWNED); 284 285 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 286 STAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 287 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 288 MTX_NOWITNESS); 289 for (i = 0; i < WITNESS_COUNT; i++) 290 witness_free(&w_data[i]); 291 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 292 witness_child_free(&w_childdata[i]); 293 for (i = 0; i < LOCK_CHILDCOUNT; i++) 294 witness_lock_list_free(&w_locklistdata[i]); 295 296 /* First add in all the specified order lists. */ 297 for (order = order_lists; order->w_name != NULL; order++) { 298 w = enroll(order->w_name, order->w_class); 299 if (w == NULL) 300 continue; 301 w->w_file = "order list"; 302 for (order++; order->w_name != NULL; order++) { 303 w1 = enroll(order->w_name, order->w_class); 304 if (w1 == NULL) 305 continue; 306 w1->w_file = "order list"; 307 itismychild(w, w1); 308 w = w1; 309 } 310 } 311 312 /* Iterate through all locks and add them to witness. */ 313 mtx_lock(&all_mtx); 314 STAILQ_FOREACH(lock, &all_locks, lo_list) { 315 if (lock->lo_flags & LO_WITNESS) 316 lock->lo_witness = enroll(lock->lo_type, 317 lock->lo_class); 318 else 319 lock->lo_witness = NULL; 320 } 321 mtx_unlock(&all_mtx); 322 323 /* Mark the witness code as being ready for use. */ 324 atomic_store_rel_int(&witness_cold, 0); 325 326 mtx_lock(&Giant); 327} 328SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 329 330void 331witness_init(struct lock_object *lock) 332{ 333 struct lock_class *class; 334 335 class = lock->lo_class; 336 if (lock->lo_flags & LO_INITIALIZED) 337 panic("%s: lock (%s) %s is already initialized", __func__, 338 class->lc_name, lock->lo_name); 339 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 340 (class->lc_flags & LC_RECURSABLE) == 0) 341 panic("%s: lock (%s) %s can not be recursable", __func__, 342 class->lc_name, lock->lo_name); 343 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 344 (class->lc_flags & LC_SLEEPABLE) == 0) 345 panic("%s: lock (%s) %s can not be sleepable", __func__, 346 class->lc_name, lock->lo_name); 347 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 348 (class->lc_flags & LC_UPGRADABLE) == 0) 349 panic("%s: lock (%s) %s can not be upgradable", __func__, 350 class->lc_name, lock->lo_name); 351 352 mtx_lock(&all_mtx); 353 STAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 354 lock->lo_flags |= LO_INITIALIZED; 355 lock_cur_cnt++; 356 if (lock_cur_cnt > lock_max_cnt) 357 lock_max_cnt = lock_cur_cnt; 358 mtx_unlock(&all_mtx); 359 if (!witness_cold && !witness_dead && panicstr == NULL && 360 (lock->lo_flags & LO_WITNESS) != 0) 361 lock->lo_witness = enroll(lock->lo_type, class); 362 else 363 lock->lo_witness = NULL; 364} 365 366void 367witness_destroy(struct lock_object *lock) 368{ 369 struct witness *w; 370 371 if (witness_cold) 372 panic("lock (%s) %s destroyed while witness_cold", 373 lock->lo_class->lc_name, lock->lo_name); 374 if ((lock->lo_flags & LO_INITIALIZED) == 0) 375 panic("%s: lock (%s) %s is not initialized", __func__, 376 lock->lo_class->lc_name, lock->lo_name); 377 378 /* XXX: need to verify that no one holds the lock */ 379 w = lock->lo_witness; 380 if (w != NULL) { 381 mtx_lock_spin(&w_mtx); 382 w->w_refcount--; 383 if (w->w_refcount == 0) { 384 CTR2(KTR_WITNESS, 385 "%s: marking witness %s as dead", __func__, w->w_name); 386 w->w_name = "(dead)"; 387 w->w_file = "(dead)"; 388 w->w_line = 0; 389 } 390 mtx_unlock_spin(&w_mtx); 391 } 392 393 mtx_lock(&all_mtx); 394 lock_cur_cnt--; 395 STAILQ_REMOVE(&all_locks, lock, lock_object, lo_list); 396 lock->lo_flags &= ~LO_INITIALIZED; 397 mtx_unlock(&all_mtx); 398} 399 400static void 401witness_display_list(void(*prnt)(const char *fmt, ...), 402 struct witness_list *list) 403{ 404 struct witness *w, *w1; 405 int found; 406 407 STAILQ_FOREACH(w, list, w_typelist) { 408 if (w->w_file == NULL) 409 continue; 410 found = 0; 411 STAILQ_FOREACH(w1, list, w_typelist) { 412 if (isitmychild(w1, w)) { 413 found++; 414 break; 415 } 416 } 417 if (found) 418 continue; 419 /* 420 * This lock has no anscestors, display its descendants. 421 */ 422 witness_displaydescendants(prnt, w); 423 } 424} 425 426static void 427witness_display(void(*prnt)(const char *fmt, ...)) 428{ 429 struct witness *w; 430 431 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 432 witness_levelall(); 433 434 /* 435 * First, handle sleep locks which have been acquired at least 436 * once. 437 */ 438 prnt("Sleep locks:\n"); 439 witness_display_list(prnt, &w_sleep); 440 441 /* 442 * Now do spin locks which have been acquired at least once. 443 */ 444 prnt("\nSpin locks:\n"); 445 witness_display_list(prnt, &w_spin); 446 447 /* 448 * Finally, any locks which have not been acquired yet. 449 */ 450 prnt("\nLocks which were never acquired:\n"); 451 STAILQ_FOREACH(w, &w_all, w_list) { 452 if (w->w_file != NULL) 453 continue; 454 prnt("%s\n", w->w_name); 455 } 456} 457 458void 459witness_lock(struct lock_object *lock, int flags, const char *file, int line) 460{ 461 struct lock_list_entry **lock_list, *lle; 462 struct lock_instance *lock1, *lock2; 463 struct lock_class *class; 464 struct witness *w, *w1; 465 struct thread *td; 466 int i, j; 467#ifdef DDB 468 int go_into_ddb = 0; 469#endif /* DDB */ 470 471 if (witness_cold || witness_dead || lock->lo_witness == NULL || 472 panicstr != NULL) 473 return; 474 w = lock->lo_witness; 475 class = lock->lo_class; 476 td = curthread; 477 478 if (class->lc_flags & LC_SLEEPLOCK) { 479 /* 480 * Since spin locks include a critical section, this check 481 * impliclty enforces a lock order of all sleep locks before 482 * all spin locks. 483 */ 484 if (td->td_critnest != 0 && (flags & LOP_TRYLOCK) == 0) 485 panic("blockable sleep lock (%s) %s @ %s:%d", 486 class->lc_name, lock->lo_name, file, line); 487 lock_list = &td->td_sleeplocks; 488 } else 489 lock_list = PCPU_PTR(spinlocks); 490 491 /* 492 * Try locks do not block if they fail to acquire the lock, thus 493 * there is no danger of deadlocks or of switching while holding a 494 * spin lock if we acquire a lock via a try operation. 495 */ 496 if (flags & LOP_TRYLOCK) 497 goto out; 498 499 /* 500 * Is this the first lock acquired? If so, then no order checking 501 * is needed. 502 */ 503 if (*lock_list == NULL) 504 goto out; 505 506 /* 507 * Check to see if we are recursing on a lock we already own. 508 */ 509 lock1 = find_instance(*lock_list, lock); 510 if (lock1 != NULL) { 511 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 512 (flags & LOP_EXCLUSIVE) == 0) { 513 printf("shared lock of (%s) %s @ %s:%d\n", 514 class->lc_name, lock->lo_name, file, line); 515 printf("while exclusively locked from %s:%d\n", 516 lock1->li_file, lock1->li_line); 517 panic("share->excl"); 518 } 519 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 520 (flags & LOP_EXCLUSIVE) != 0) { 521 printf("exclusive lock of (%s) %s @ %s:%d\n", 522 class->lc_name, lock->lo_name, file, line); 523 printf("while share locked from %s:%d\n", 524 lock1->li_file, lock1->li_line); 525 panic("excl->share"); 526 } 527 lock1->li_flags++; 528 if ((lock->lo_flags & LO_RECURSABLE) == 0) { 529 printf( 530 "recursed on non-recursive lock (%s) %s @ %s:%d\n", 531 class->lc_name, lock->lo_name, file, line); 532 printf("first acquired @ %s:%d\n", lock1->li_file, 533 lock1->li_line); 534 panic("recurse"); 535 } 536 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 537 td->td_proc->p_pid, lock->lo_name, 538 lock1->li_flags & LI_RECURSEMASK); 539 lock1->li_file = file; 540 lock1->li_line = line; 541 return; 542 } 543 544 /* 545 * Check for duplicate locks of the same type. Note that we only 546 * have to check for this on the last lock we just acquired. Any 547 * other cases will be caught as lock order violations. 548 */ 549 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 550 w1 = lock1->li_lock->lo_witness; 551 if (w1 == w) { 552 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK)) 553 goto out; 554 w->w_same_squawked = 1; 555 printf("acquiring duplicate lock of same type: \"%s\"\n", 556 lock->lo_type); 557 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 558 lock1->li_file, lock1->li_line); 559 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 560#ifdef DDB 561 go_into_ddb = 1; 562#endif /* DDB */ 563 goto out; 564 } 565 MPASS(!mtx_owned(&w_mtx)); 566 mtx_lock_spin(&w_mtx); 567 /* 568 * If we have a known higher number just say ok 569 */ 570 if (witness_watch > 1 && w->w_level > w1->w_level) { 571 mtx_unlock_spin(&w_mtx); 572 goto out; 573 } 574 if (isitmydescendant(w1, w)) { 575 mtx_unlock_spin(&w_mtx); 576 goto out; 577 } 578 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 579 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 580 581 MPASS(j < WITNESS_COUNT); 582 lock1 = &lle->ll_children[i]; 583 w1 = lock1->li_lock->lo_witness; 584 585 /* 586 * If this lock doesn't undergo witness checking, 587 * then skip it. 588 */ 589 if (w1 == NULL) { 590 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 591 ("lock missing witness structure")); 592 continue; 593 } 594 /* 595 * If we are locking Giant and we slept with this 596 * lock, then skip it. 597 */ 598 if ((lock1->li_flags & LI_SLEPT) != 0 && 599 lock == &Giant.mtx_object) 600 continue; 601 /* 602 * If we are locking a sleepable lock and this lock 603 * isn't sleepable and isn't Giant, we want to treat 604 * it as a lock order violation to enfore a general 605 * lock order of sleepable locks before non-sleepable 606 * locks. Thus, we only bother checking the lock 607 * order hierarchy if we pass the initial test. 608 */ 609 if (!((lock->lo_flags & LO_SLEEPABLE) != 0 && 610 ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && 611 lock1->li_lock != &Giant.mtx_object)) && 612 !isitmydescendant(w, w1)) 613 continue; 614 /* 615 * We have a lock order violation, check to see if it 616 * is allowed or has already been yelled about. 617 */ 618 mtx_unlock_spin(&w_mtx); 619 if (blessed(w, w1)) 620 goto out; 621 if (lock1->li_lock == &Giant.mtx_object) { 622 if (w1->w_Giant_squawked) 623 goto out; 624 else 625 w1->w_Giant_squawked = 1; 626 } else { 627 if (w1->w_other_squawked) 628 goto out; 629 else 630 w1->w_other_squawked = 1; 631 } 632 /* 633 * Ok, yell about it. 634 */ 635 printf("lock order reversal\n"); 636 /* 637 * Try to locate an earlier lock with 638 * witness w in our list. 639 */ 640 do { 641 lock2 = &lle->ll_children[i]; 642 MPASS(lock2->li_lock != NULL); 643 if (lock2->li_lock->lo_witness == w) 644 break; 645 i--; 646 if (i == 0 && lle->ll_next != NULL) { 647 lle = lle->ll_next; 648 i = lle->ll_count - 1; 649 MPASS(i != 0); 650 } 651 } while (i >= 0); 652 if (i < 0) { 653 printf(" 1st %p %s (%s) @ %s:%d\n", 654 lock1->li_lock, lock1->li_lock->lo_name, 655 lock1->li_lock->lo_type, lock1->li_file, 656 lock1->li_line); 657 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 658 lock->lo_name, lock->lo_type, file, line); 659 } else { 660 printf(" 1st %p %s (%s) @ %s:%d\n", 661 lock2->li_lock, lock2->li_lock->lo_name, 662 lock2->li_lock->lo_type, lock2->li_file, 663 lock2->li_line); 664 printf(" 2nd %p %s (%s) @ %s:%d\n", 665 lock1->li_lock, lock1->li_lock->lo_name, 666 lock1->li_lock->lo_type, lock1->li_file, 667 lock1->li_line); 668 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 669 lock->lo_name, lock->lo_type, file, line); 670 } 671#ifdef DDB 672 go_into_ddb = 1; 673#endif /* DDB */ 674 goto out; 675 } 676 } 677 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 678 /* 679 * Don't build a new relationship if we are locking Giant just 680 * after waking up and the previous lock in the list was acquired 681 * prior to blocking. 682 */ 683 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 684 mtx_unlock_spin(&w_mtx); 685 else { 686 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 687 lock->lo_type, lock1->li_lock->lo_type); 688 if (!itismychild(lock1->li_lock->lo_witness, w)) 689 mtx_unlock_spin(&w_mtx); 690 } 691 692out: 693#ifdef DDB 694 if (witness_ddb && go_into_ddb) 695 Debugger(__func__); 696#endif /* DDB */ 697 w->w_file = file; 698 w->w_line = line; 699 700 lle = *lock_list; 701 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 702 lle = witness_lock_list_get(); 703 if (lle == NULL) 704 return; 705 lle->ll_next = *lock_list; 706 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 707 td->td_proc->p_pid, lle); 708 *lock_list = lle; 709 } 710 lock1 = &lle->ll_children[lle->ll_count++]; 711 lock1->li_lock = lock; 712 lock1->li_line = line; 713 lock1->li_file = file; 714 if ((flags & LOP_EXCLUSIVE) != 0) 715 lock1->li_flags = LI_EXCLUSIVE; 716 else 717 lock1->li_flags = 0; 718 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 719 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 720} 721 722void 723witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 724{ 725 struct lock_instance *instance; 726 struct lock_class *class; 727 728 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 729 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 730 return; 731 class = lock->lo_class; 732 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 733 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 734 class->lc_name, lock->lo_name, file, line); 735 if ((flags & LOP_TRYLOCK) == 0) 736 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 737 lock->lo_name, file, line); 738 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 739 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 740 class->lc_name, lock->lo_name, file, line); 741 instance = find_instance(curthread->td_sleeplocks, lock); 742 if (instance == NULL) 743 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 744 class->lc_name, lock->lo_name, file, line); 745 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 746 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 747 class->lc_name, lock->lo_name, file, line); 748 if ((instance->li_flags & LI_RECURSEMASK) != 0) 749 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 750 class->lc_name, lock->lo_name, 751 instance->li_flags & LI_RECURSEMASK, file, line); 752 instance->li_flags |= LI_EXCLUSIVE; 753} 754 755void 756witness_downgrade(struct lock_object *lock, int flags, const char *file, 757 int line) 758{ 759 struct lock_instance *instance; 760 struct lock_class *class; 761 762 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 763 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 764 return; 765 class = lock->lo_class; 766 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 767 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 768 class->lc_name, lock->lo_name, file, line); 769 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 770 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 771 class->lc_name, lock->lo_name, file, line); 772 instance = find_instance(curthread->td_sleeplocks, lock); 773 if (instance == NULL) 774 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 775 class->lc_name, lock->lo_name, file, line); 776 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 777 panic("downgrade of shared lock (%s) %s @ %s:%d", 778 class->lc_name, lock->lo_name, file, line); 779 if ((instance->li_flags & LI_RECURSEMASK) != 0) 780 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 781 class->lc_name, lock->lo_name, 782 instance->li_flags & LI_RECURSEMASK, file, line); 783 instance->li_flags &= ~LI_EXCLUSIVE; 784} 785 786void 787witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 788{ 789 struct lock_list_entry **lock_list, *lle; 790 struct lock_instance *instance; 791 struct lock_class *class; 792 struct thread *td; 793 register_t s; 794 int i, j; 795 796 if (witness_cold || witness_dead || lock->lo_witness == NULL || 797 panicstr != NULL) 798 return; 799 td = curthread; 800 class = lock->lo_class; 801 if (class->lc_flags & LC_SLEEPLOCK) 802 lock_list = &td->td_sleeplocks; 803 else 804 lock_list = PCPU_PTR(spinlocks); 805 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 806 for (i = 0; i < (*lock_list)->ll_count; i++) { 807 instance = &(*lock_list)->ll_children[i]; 808 if (instance->li_lock == lock) { 809 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 810 (flags & LOP_EXCLUSIVE) == 0) { 811 printf( 812 "shared unlock of (%s) %s @ %s:%d\n", 813 class->lc_name, lock->lo_name, 814 file, line); 815 printf( 816 "while exclusively locked from %s:%d\n", 817 instance->li_file, 818 instance->li_line); 819 panic("excl->ushare"); 820 } 821 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 822 (flags & LOP_EXCLUSIVE) != 0) { 823 printf( 824 "exclusive unlock of (%s) %s @ %s:%d\n", 825 class->lc_name, lock->lo_name, 826 file, line); 827 printf( 828 "while share locked from %s:%d\n", 829 instance->li_file, 830 instance->li_line); 831 panic("share->uexcl"); 832 } 833 /* If we are recursed, unrecurse. */ 834 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 835 CTR4(KTR_WITNESS, 836 "%s: pid %d unrecursed on %s r=%d", __func__, 837 td->td_proc->p_pid, 838 instance->li_lock->lo_name, 839 instance->li_flags); 840 instance->li_flags--; 841 return; 842 } 843 s = intr_disable(); 844 CTR4(KTR_WITNESS, 845 "%s: pid %d removed %s from lle[%d]", __func__, 846 td->td_proc->p_pid, 847 instance->li_lock->lo_name, 848 (*lock_list)->ll_count - 1); 849 (*lock_list)->ll_count--; 850 for (j = i; j < (*lock_list)->ll_count; j++) 851 (*lock_list)->ll_children[j] = 852 (*lock_list)->ll_children[j + 1]; 853 intr_restore(s); 854 if ((*lock_list)->ll_count == 0) { 855 lle = *lock_list; 856 *lock_list = lle->ll_next; 857 CTR3(KTR_WITNESS, 858 "%s: pid %d removed lle %p", __func__, 859 td->td_proc->p_pid, lle); 860 witness_lock_list_free(lle); 861 } 862 return; 863 } 864 } 865 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 866 file, line); 867} 868 869/* 870 * Warn if any held locks are not sleepable. Note that Giant and the lock 871 * passed in are both special cases since they are both released during the 872 * sleep process and aren't actually held while the thread is asleep. 873 */ 874int 875witness_sleep(int check_only, struct lock_object *lock, const char *file, 876 int line) 877{ 878 struct lock_list_entry **lock_list, *lle; 879 struct lock_instance *lock1; 880 struct thread *td; 881 int i, n; 882 883 if (witness_dead || panicstr != NULL) 884 return (0); 885 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 886 n = 0; 887 /* 888 * Preemption bad because we need PCPU_PTR(spinlocks) to not change. 889 */ 890 critical_enter(); 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) { 918 lock_list = PCPU_PTR(spinlocks); 919 goto again; 920 } 921#ifdef DDB 922 if (witness_ddb && n) 923 Debugger(__func__); 924#endif /* DDB */ 925 critical_exit(); 926 return (n); 927} 928 929static struct witness * 930enroll(const char *description, struct lock_class *lock_class) 931{ 932 struct witness *w; 933 934 if (!witness_watch || witness_dead || panicstr != NULL) 935 return (NULL); 936 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 937 return (NULL); 938 mtx_lock_spin(&w_mtx); 939 STAILQ_FOREACH(w, &w_all, w_list) { 940 if (strcmp(description, w->w_name) == 0) { 941 w->w_refcount++; 942 mtx_unlock_spin(&w_mtx); 943 if (lock_class != w->w_class) 944 panic( 945 "lock (%s) %s does not match earlier (%s) lock", 946 description, lock_class->lc_name, 947 w->w_class->lc_name); 948 return (w); 949 } 950 } 951 /* 952 * This isn't quite right, as witness_cold is still 0 while we 953 * enroll all the locks initialized before witness_initialize(). 954 */ 955 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 956 mtx_unlock_spin(&w_mtx); 957 panic("spin lock %s not in order list", description); 958 } 959 if ((w = witness_get()) == NULL) 960 return (NULL); 961 w->w_name = description; 962 w->w_class = lock_class; 963 w->w_refcount = 1; 964 STAILQ_INSERT_HEAD(&w_all, w, w_list); 965 if (lock_class->lc_flags & LC_SPINLOCK) 966 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 967 else if (lock_class->lc_flags & LC_SLEEPLOCK) 968 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 969 else { 970 mtx_unlock_spin(&w_mtx); 971 panic("lock class %s is not sleep or spin", 972 lock_class->lc_name); 973 } 974 mtx_unlock_spin(&w_mtx); 975 return (w); 976} 977 978static int 979itismychild(struct witness *parent, struct witness *child) 980{ 981 static int recursed; 982 struct witness_child_list_entry **wcl; 983 struct witness_list *list; 984 985 MPASS(child != NULL && parent != NULL); 986 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 987 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 988 panic( 989 "%s: parent (%s) and child (%s) are not the same lock type", 990 __func__, parent->w_class->lc_name, 991 child->w_class->lc_name); 992 993 /* 994 * Insert "child" after "parent" 995 */ 996 wcl = &parent->w_children; 997 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 998 wcl = &(*wcl)->wcl_next; 999 if (*wcl == NULL) { 1000 *wcl = witness_child_get(); 1001 if (*wcl == NULL) 1002 return (1); 1003 } 1004 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1005 1006 /* 1007 * Now prune whole tree. We look for cases where a lock is now 1008 * both a descendant and a direct child of a given lock. In that 1009 * case, we want to remove the direct child link from the tree. 1010 */ 1011 if (recursed) 1012 return (0); 1013 recursed = 1; 1014 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1015 list = &w_sleep; 1016 else 1017 list = &w_spin; 1018 STAILQ_FOREACH(child, list, w_typelist) { 1019 STAILQ_FOREACH(parent, list, w_typelist) { 1020 if (!isitmychild(parent, child)) 1021 continue; 1022 removechild(parent, child); 1023 if (isitmydescendant(parent, child)) 1024 continue; 1025 itismychild(parent, child); 1026 } 1027 } 1028 recursed = 0; 1029 witness_levelall(); 1030 return (0); 1031} 1032 1033static void 1034removechild(struct witness *parent, struct witness *child) 1035{ 1036 struct witness_child_list_entry **wcl, *wcl1; 1037 int i; 1038 1039 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1040 for (i = 0; i < (*wcl)->wcl_count; i++) 1041 if ((*wcl)->wcl_children[i] == child) 1042 goto found; 1043 return; 1044found: 1045 (*wcl)->wcl_count--; 1046 if ((*wcl)->wcl_count > i) 1047 (*wcl)->wcl_children[i] = 1048 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1049 MPASS((*wcl)->wcl_children[i] != NULL); 1050 if ((*wcl)->wcl_count != 0) 1051 return; 1052 wcl1 = *wcl; 1053 *wcl = wcl1->wcl_next; 1054 witness_child_free(wcl1); 1055} 1056 1057static int 1058isitmychild(struct witness *parent, struct witness *child) 1059{ 1060 struct witness_child_list_entry *wcl; 1061 int i; 1062 1063 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1064 for (i = 0; i < wcl->wcl_count; i++) { 1065 if (wcl->wcl_children[i] == child) 1066 return (1); 1067 } 1068 } 1069 return (0); 1070} 1071 1072static int 1073isitmydescendant(struct witness *parent, struct witness *child) 1074{ 1075 struct witness_child_list_entry *wcl; 1076 int i, j; 1077 1078 if (isitmychild(parent, child)) 1079 return (1); 1080 j = 0; 1081 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1082 MPASS(j < 1000); 1083 for (i = 0; i < wcl->wcl_count; i++) { 1084 if (isitmydescendant(wcl->wcl_children[i], child)) 1085 return (1); 1086 } 1087 j++; 1088 } 1089 return (0); 1090} 1091 1092void 1093witness_levelall (void) 1094{ 1095 struct witness_list *list; 1096 struct witness *w, *w1; 1097 1098 /* 1099 * First clear all levels. 1100 */ 1101 STAILQ_FOREACH(w, &w_all, w_list) { 1102 w->w_level = 0; 1103 } 1104 1105 /* 1106 * Look for locks with no parent and level all their descendants. 1107 */ 1108 STAILQ_FOREACH(w, &w_all, w_list) { 1109 /* 1110 * This is just an optimization, technically we could get 1111 * away just walking the all list each time. 1112 */ 1113 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1114 list = &w_sleep; 1115 else 1116 list = &w_spin; 1117 STAILQ_FOREACH(w1, list, w_typelist) { 1118 if (isitmychild(w1, w)) 1119 goto skip; 1120 } 1121 witness_leveldescendents(w, 0); 1122 skip: 1123 } 1124} 1125 1126static void 1127witness_leveldescendents(struct witness *parent, int level) 1128{ 1129 struct witness_child_list_entry *wcl; 1130 int i; 1131 1132 if (parent->w_level < level) 1133 parent->w_level = level; 1134 level++; 1135 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1136 for (i = 0; i < wcl->wcl_count; i++) 1137 witness_leveldescendents(wcl->wcl_children[i], level); 1138} 1139 1140static void 1141witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1142 struct witness *parent) 1143{ 1144 struct witness_child_list_entry *wcl; 1145 int i, level; 1146 1147 level = parent->w_level; 1148 prnt("%-2d", level); 1149 for (i = 0; i < level; i++) 1150 prnt(" "); 1151 prnt("%s", parent->w_name); 1152 if (parent->w_file != NULL) 1153 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1154 parent->w_line); 1155 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1156 for (i = 0; i < wcl->wcl_count; i++) 1157 witness_displaydescendants(prnt, 1158 wcl->wcl_children[i]); 1159} 1160 1161static int 1162blessed(struct witness *w1, struct witness *w2) 1163{ 1164 int i; 1165 struct witness_blessed *b; 1166 1167 for (i = 0; i < blessed_count; i++) { 1168 b = &blessed_list[i]; 1169 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1170 if (strcmp(w2->w_name, b->b_lock2) == 0) 1171 return (1); 1172 continue; 1173 } 1174 if (strcmp(w1->w_name, b->b_lock2) == 0) 1175 if (strcmp(w2->w_name, b->b_lock1) == 0) 1176 return (1); 1177 } 1178 return (0); 1179} 1180 1181static struct witness * 1182witness_get(void) 1183{ 1184 struct witness *w; 1185 1186 if (witness_dead) { 1187 mtx_unlock_spin(&w_mtx); 1188 return (NULL); 1189 } 1190 if (STAILQ_EMPTY(&w_free)) { 1191 witness_dead = 1; 1192 mtx_unlock_spin(&w_mtx); 1193 printf("%s: witness exhausted\n", __func__); 1194 return (NULL); 1195 } 1196 w = STAILQ_FIRST(&w_free); 1197 STAILQ_REMOVE_HEAD(&w_free, w_list); 1198 bzero(w, sizeof(*w)); 1199 return (w); 1200} 1201 1202static void 1203witness_free(struct witness *w) 1204{ 1205 1206 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1207} 1208 1209static struct witness_child_list_entry * 1210witness_child_get(void) 1211{ 1212 struct witness_child_list_entry *wcl; 1213 1214 if (witness_dead) { 1215 mtx_unlock_spin(&w_mtx); 1216 return (NULL); 1217 } 1218 wcl = w_child_free; 1219 if (wcl == NULL) { 1220 witness_dead = 1; 1221 mtx_unlock_spin(&w_mtx); 1222 printf("%s: witness exhausted\n", __func__); 1223 return (NULL); 1224 } 1225 w_child_free = wcl->wcl_next; 1226 bzero(wcl, sizeof(*wcl)); 1227 return (wcl); 1228} 1229 1230static void 1231witness_child_free(struct witness_child_list_entry *wcl) 1232{ 1233 1234 wcl->wcl_next = w_child_free; 1235 w_child_free = wcl; 1236} 1237 1238static struct lock_list_entry * 1239witness_lock_list_get(void) 1240{ 1241 struct lock_list_entry *lle; 1242 1243 if (witness_dead) 1244 return (NULL); 1245 mtx_lock_spin(&w_mtx); 1246 lle = w_lock_list_free; 1247 if (lle == NULL) { 1248 witness_dead = 1; 1249 mtx_unlock_spin(&w_mtx); 1250 printf("%s: witness exhausted\n", __func__); 1251 return (NULL); 1252 } 1253 w_lock_list_free = lle->ll_next; 1254 mtx_unlock_spin(&w_mtx); 1255 bzero(lle, sizeof(*lle)); 1256 return (lle); 1257} 1258 1259static void 1260witness_lock_list_free(struct lock_list_entry *lle) 1261{ 1262 1263 mtx_lock_spin(&w_mtx); 1264 lle->ll_next = w_lock_list_free; 1265 w_lock_list_free = lle; 1266 mtx_unlock_spin(&w_mtx); 1267} 1268 1269static struct lock_instance * 1270find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1271{ 1272 struct lock_list_entry *lle; 1273 struct lock_instance *instance; 1274 int i; 1275 1276 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1277 for (i = lle->ll_count - 1; i >= 0; i--) { 1278 instance = &lle->ll_children[i]; 1279 if (instance->li_lock == lock) 1280 return (instance); 1281 } 1282 return (NULL); 1283} 1284 1285int 1286witness_list_locks(struct lock_list_entry **lock_list) 1287{ 1288 struct lock_list_entry *lle; 1289 struct lock_instance *instance; 1290 struct lock_object *lock; 1291 int i, nheld; 1292 1293 nheld = 0; 1294 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1295 for (i = lle->ll_count - 1; i >= 0; i--) { 1296 instance = &lle->ll_children[i]; 1297 lock = instance->li_lock; 1298 printf("%s %s %s", 1299 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1300 "exclusive" : "shared", 1301 lock->lo_class->lc_name, lock->lo_name); 1302 if (lock->lo_type != lock->lo_name) 1303 printf("(%s) ", lock->lo_type); 1304 printf(" (%p) locked @ %s:%d\n", 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 */ 1314int 1315witness_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) { 1346 /* 1347 * Preemption bad because we need PCPU_PTR(spinlocks) to not 1348 * change. 1349 */ 1350 critical_enter(); 1351 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1352 critical_exit(); 1353 } 1354 return (nheld); 1355} 1356 1357void 1358witness_save(struct lock_object *lock, const char **filep, int *linep) 1359{ 1360 struct lock_instance *instance; 1361 1362 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1363 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1364 return; 1365 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1366 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1367 lock->lo_class->lc_name, lock->lo_name); 1368 instance = find_instance(curthread->td_sleeplocks, lock); 1369 if (instance == NULL) 1370 panic("%s: lock (%s) %s not locked", __func__, 1371 lock->lo_class->lc_name, lock->lo_name); 1372 *filep = instance->li_file; 1373 *linep = instance->li_line; 1374} 1375 1376void 1377witness_restore(struct lock_object *lock, const char *file, int line) 1378{ 1379 struct lock_instance *instance; 1380 1381 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1382 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1383 return; 1384 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1385 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1386 lock->lo_class->lc_name, lock->lo_name); 1387 instance = find_instance(curthread->td_sleeplocks, lock); 1388 if (instance == NULL) 1389 panic("%s: lock (%s) %s not locked", __func__, 1390 lock->lo_class->lc_name, lock->lo_name); 1391 lock->lo_witness->w_file = file; 1392 lock->lo_witness->w_line = line; 1393 instance->li_file = file; 1394 instance->li_line = line; 1395} 1396 1397void 1398witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1399{ 1400#ifdef INVARIANT_SUPPORT 1401 struct lock_instance *instance; 1402 1403 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1404 return; 1405 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1406 instance = find_instance(curthread->td_sleeplocks, lock); 1407 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1408 instance = find_instance(PCPU_GET(spinlocks), lock); 1409 else { 1410 panic("Lock (%s) %s is not sleep or spin!", 1411 lock->lo_class->lc_name, lock->lo_name); 1412 return; 1413 } 1414 switch (flags) { 1415 case LA_UNLOCKED: 1416 if (instance != NULL) 1417 panic("Lock (%s) %s locked @ %s:%d.", 1418 lock->lo_class->lc_name, lock->lo_name, file, line); 1419 break; 1420 case LA_LOCKED: 1421 case LA_LOCKED | LA_RECURSED: 1422 case LA_LOCKED | LA_NOTRECURSED: 1423 case LA_SLOCKED: 1424 case LA_SLOCKED | LA_RECURSED: 1425 case LA_SLOCKED | LA_NOTRECURSED: 1426 case LA_XLOCKED: 1427 case LA_XLOCKED | LA_RECURSED: 1428 case LA_XLOCKED | LA_NOTRECURSED: 1429 if (instance == NULL) { 1430 panic("Lock (%s) %s not locked @ %s:%d.", 1431 lock->lo_class->lc_name, lock->lo_name, file, line); 1432 break; 1433 } 1434 if ((flags & LA_XLOCKED) != 0 && 1435 (instance->li_flags & LI_EXCLUSIVE) == 0) 1436 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1437 lock->lo_class->lc_name, lock->lo_name, file, line); 1438 if ((flags & LA_SLOCKED) != 0 && 1439 (instance->li_flags & LI_EXCLUSIVE) != 0) 1440 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1441 lock->lo_class->lc_name, lock->lo_name, file, line); 1442 if ((flags & LA_RECURSED) != 0 && 1443 (instance->li_flags & LI_RECURSEMASK) == 0) 1444 panic("Lock (%s) %s not recursed @ %s:%d.", 1445 lock->lo_class->lc_name, lock->lo_name, file, line); 1446 if ((flags & LA_NOTRECURSED) != 0 && 1447 (instance->li_flags & LI_RECURSEMASK) != 0) 1448 panic("Lock (%s) %s recursed @ %s:%d.", 1449 lock->lo_class->lc_name, lock->lo_name, file, line); 1450 break; 1451 default: 1452 panic("Invalid lock assertion at %s:%d.", file, line); 1453 1454 } 1455#endif /* INVARIANT_SUPPORT */ 1456} 1457 1458#ifdef DDB 1459 1460DB_SHOW_COMMAND(locks, db_witness_list) 1461{ 1462 struct thread *td; 1463 pid_t pid; 1464 struct proc *p; 1465 1466 if (have_addr) { 1467 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1468 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1469 ((addr >> 16) % 16) * 10000; 1470 /* sx_slock(&allproc_lock); */ 1471 FOREACH_PROC_IN_SYSTEM(p) { 1472 if (p->p_pid == pid) 1473 break; 1474 } 1475 /* sx_sunlock(&allproc_lock); */ 1476 if (p == NULL) { 1477 db_printf("pid %d not found\n", pid); 1478 return; 1479 } 1480 FOREACH_THREAD_IN_PROC(p, td) { 1481 witness_list(td); 1482 } 1483 } else { 1484 td = curthread; 1485 witness_list(td); 1486 } 1487} 1488 1489DB_SHOW_COMMAND(witness, db_witness_display) 1490{ 1491 1492 witness_display(db_printf); 1493} 1494#endif 1495