230 NULL 231}; 232 233/* 234 * Pairs of locks which have been blessed 235 * Don't complain about order problems with blessed locks 236 */ 237static struct witness_blessed blessed_list[] = { 238}; 239static int blessed_count = 240 sizeof(blessed_list) / sizeof(struct witness_blessed); 241 242/* 243 * List of all locks in the system. 244 */ 245STAILQ_HEAD(, lock_object) all_locks = STAILQ_HEAD_INITIALIZER(all_locks); 246 247static struct mtx all_mtx = { 248 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 249 "All locks list", /* mtx_object.lo_name */ 250 LO_INITIALIZED, /* mtx_object.lo_flags */ 251 { 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 */ 261static int witness_cold = 1; 262 263/* 264 * Global variables for book keeping. 265 */ 266static int lock_cur_cnt; 267static int lock_max_cnt; 268 269/* 270 * The WITNESS-enabled diagnostic code. 271 */ 272static void 273witness_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 STAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 289 mtx_init(&w_mtx, "witness lock", MTX_SPIN | MTX_QUIET | MTX_NOWITNESS); 290 for (i = 0; i < WITNESS_COUNT; i++) 291 witness_free(&w_data[i]); 292 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 293 witness_child_free(&w_childdata[i]); 294 for (i = 0; i < LOCK_CHILDCOUNT; i++) 295 witness_lock_list_free(&w_locklistdata[i]); 296 297 /* First add in all the specified order lists. */ 298 for (order = order_lists; order->w_name != NULL; order++) { 299 w = enroll(order->w_name, order->w_class); 300 if (w == NULL) 301 continue; 302 w->w_file = "order list"; 303 for (order++; order->w_name != NULL; order++) { 304 w1 = enroll(order->w_name, order->w_class); 305 if (w1 == NULL) 306 continue; 307 w1->w_file = "order list"; 308 itismychild(w, w1); 309 w = w1; 310 } 311 } 312 313 /* Iterate through all locks and add them to witness. */ 314 mtx_lock(&all_mtx); 315 STAILQ_FOREACH(lock, &all_locks, lo_list) { 316 if (lock->lo_flags & LO_WITNESS) 317 lock->lo_witness = enroll(lock->lo_name, 318 lock->lo_class); 319 else 320 lock->lo_witness = NULL; 321 } 322 mtx_unlock(&all_mtx); 323 324 /* Mark the witness code as being ready for use. */ 325 atomic_store_rel_int(&witness_cold, 0); 326 327 mtx_lock(&Giant); 328} 329SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 330 331void 332witness_init(struct lock_object *lock) 333{ 334 struct lock_class *class; 335 336 class = lock->lo_class; 337 if (lock->lo_flags & LO_INITIALIZED) 338 panic("%s: lock (%s) %s is already initialized", __func__, 339 class->lc_name, lock->lo_name); 340 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 341 (class->lc_flags & LC_RECURSABLE) == 0) 342 panic("%s: lock (%s) %s can not be recursable", __func__, 343 class->lc_name, lock->lo_name); 344 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 345 (class->lc_flags & LC_SLEEPABLE) == 0) 346 panic("%s: lock (%s) %s can not be sleepable", __func__, 347 class->lc_name, lock->lo_name); 348 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 349 (class->lc_flags & LC_UPGRADABLE) == 0) 350 panic("%s: lock (%s) %s can not be upgradable", __func__, 351 class->lc_name, lock->lo_name); 352 353 mtx_lock(&all_mtx); 354 STAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 355 lock->lo_flags |= LO_INITIALIZED; 356 lock_cur_cnt++; 357 if (lock_cur_cnt > lock_max_cnt) 358 lock_max_cnt = lock_cur_cnt; 359 mtx_unlock(&all_mtx); 360 if (!witness_cold && !witness_dead && panicstr == NULL && 361 (lock->lo_flags & LO_WITNESS) != 0) 362 lock->lo_witness = enroll(lock->lo_name, class); 363 else 364 lock->lo_witness = NULL; 365} 366 367void 368witness_destroy(struct lock_object *lock) 369{ 370 struct witness *w; 371 372 if (witness_cold) 373 panic("lock (%s) %s destroyed while witness_cold", 374 lock->lo_class->lc_name, lock->lo_name); 375 if ((lock->lo_flags & LO_INITIALIZED) == 0) 376 panic("%s: lock (%s) %s is not initialized", __func__, 377 lock->lo_class->lc_name, lock->lo_name); 378 379 /* XXX: need to verify that no one holds the lock */ 380 w = lock->lo_witness; 381 if (w != NULL) { 382 mtx_lock_spin(&w_mtx); 383 w->w_refcount--; 384 if (w->w_refcount == 0) { 385 CTR2(KTR_WITNESS, 386 "%s: marking witness %s as dead", __func__, w->w_name); 387 w->w_name = "(dead)"; 388 w->w_file = "(dead)"; 389 w->w_line = 0; 390 } 391 mtx_unlock_spin(&w_mtx); 392 } 393 394 mtx_lock(&all_mtx); 395 lock_cur_cnt--; 396 STAILQ_REMOVE(&all_locks, lock, lock_object, lo_list); 397 lock->lo_flags &= ~LO_INITIALIZED; 398 mtx_unlock(&all_mtx); 399} 400 401static void 402witness_display_list(void(*prnt)(const char *fmt, ...), 403 struct witness_list *list) 404{ 405 struct witness *w, *w1; 406 int found; 407 408 STAILQ_FOREACH(w, list, w_typelist) { 409 if (w->w_file == NULL) 410 continue; 411 found = 0; 412 STAILQ_FOREACH(w1, list, w_typelist) { 413 if (isitmychild(w1, w)) { 414 found++; 415 break; 416 } 417 } 418 if (found) 419 continue; 420 /* 421 * This lock has no anscestors, display its descendants. 422 */ 423 witness_displaydescendants(prnt, w); 424 } 425} 426 427static void 428witness_display(void(*prnt)(const char *fmt, ...)) 429{ 430 struct witness *w; 431 432 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 433 witness_levelall(); 434 435 /* 436 * First, handle sleep locks which have been acquired at least 437 * once. 438 */ 439 prnt("Sleep locks:\n"); 440 witness_display_list(prnt, &w_sleep); 441 442 /* 443 * Now do spin locks which have been acquired at least once. 444 */ 445 prnt("\nSpin locks:\n"); 446 witness_display_list(prnt, &w_spin); 447 448 /* 449 * Finally, any locks which have not been acquired yet. 450 */ 451 prnt("\nLocks which were never acquired:\n"); 452 STAILQ_FOREACH(w, &w_all, w_list) { 453 if (w->w_file != NULL) 454 continue; 455 prnt("%s\n", w->w_name); 456 } 457} 458 459void 460witness_lock(struct lock_object *lock, int flags, const char *file, int line) 461{ 462 struct lock_list_entry **lock_list, *lle; 463 struct lock_instance *lock1, *lock2; 464 struct lock_class *class; 465 struct witness *w, *w1; 466 struct thread *td; 467 int i, j; 468#ifdef DDB 469 int go_into_ddb = 0; 470#endif /* DDB */ 471 472 if (witness_cold || witness_dead || lock->lo_witness == NULL || 473 panicstr != NULL) 474 return; 475 w = lock->lo_witness; 476 class = lock->lo_class; 477 td = curthread; 478 479 if (class->lc_flags & LC_SLEEPLOCK) { 480 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 || dup_ok(w)) 549 goto out; 550 w->w_same_squawked = 1; 551 printf("acquiring duplicate lock of same type: \"%s\"\n", 552 lock->lo_name); 553 printf(" 1st @ %s:%d\n", lock1->li_file, lock1->li_line); 554 printf(" 2nd @ %s:%d\n", file, line); 555#ifdef DDB 556 go_into_ddb = 1; 557#endif /* DDB */ 558 goto out; 559 } 560 MPASS(!mtx_owned(&w_mtx)); 561 mtx_lock_spin(&w_mtx); 562 /* 563 * If we have a known higher number just say ok 564 */ 565 if (witness_watch > 1 && w->w_level > w1->w_level) { 566 mtx_unlock_spin(&w_mtx); 567 goto out; 568 } 569 if (isitmydescendant(w1, w)) { 570 mtx_unlock_spin(&w_mtx); 571 goto out; 572 } 573 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 574 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 575 576 MPASS(j < WITNESS_COUNT); 577 lock1 = &lle->ll_children[i]; 578 w1 = lock1->li_lock->lo_witness; 579 580 /* 581 * If this lock doesn't undergo witness checking, 582 * then skip it. 583 */ 584 if (w1 == NULL) { 585 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 586 ("lock missing witness structure")); 587 continue; 588 } 589 /* 590 * If we are locking Giant and we slept with this 591 * lock, then skip it. 592 */ 593 if ((lock1->li_flags & LI_SLEPT) != 0 && 594 lock == &Giant.mtx_object) 595 continue; 596 if (!isitmydescendant(w, w1)) 597 continue; 598 /* 599 * We have a lock order violation, check to see if it 600 * is allowed or has already been yelled about. 601 */ 602 mtx_unlock_spin(&w_mtx); 603 if (blessed(w, w1)) 604 goto out; 605 if (lock1->li_lock == &Giant.mtx_object) { 606 if (w1->w_Giant_squawked) 607 goto out; 608 else 609 w1->w_Giant_squawked = 1; 610 } else { 611 if (w1->w_other_squawked) 612 goto out; 613 else 614 w1->w_other_squawked = 1; 615 } 616 /* 617 * Ok, yell about it. 618 */ 619 printf("lock order reversal\n"); 620 /* 621 * Try to locate an earlier lock with 622 * witness w in our list. 623 */ 624 do { 625 lock2 = &lle->ll_children[i]; 626 MPASS(lock2->li_lock != NULL); 627 if (lock2->li_lock->lo_witness == w) 628 break; 629 i--; 630 if (i == 0 && lle->ll_next != NULL) { 631 lle = lle->ll_next; 632 i = lle->ll_count - 1; 633 MPASS(i != 0); 634 } 635 } while (i >= 0); 636 if (i < 0) { 637 printf(" 1st %p %s @ %s:%d\n", lock1->li_lock, 638 lock1->li_lock->lo_name, lock1->li_file, 639 lock1->li_line); 640 printf(" 2nd %p %s @ %s:%d\n", lock, 641 lock->lo_name, file, line); 642 } else { 643 printf(" 1st %p %s @ %s:%d\n", lock2->li_lock, 644 lock2->li_lock->lo_name, lock2->li_file, 645 lock2->li_line); 646 printf(" 2nd %p %s @ %s:%d\n", lock1->li_lock, 647 lock1->li_lock->lo_name, lock1->li_file, 648 lock1->li_line); 649 printf(" 3rd %p %s @ %s:%d\n", lock, 650 lock->lo_name, file, line); 651 } 652#ifdef DDB 653 go_into_ddb = 1; 654#endif /* DDB */ 655 goto out; 656 } 657 } 658 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 659 /* 660 * Don't build a new relationship if we are locking Giant just 661 * after waking up and the previous lock in the list was acquired 662 * prior to blocking. 663 */ 664 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 665 mtx_unlock_spin(&w_mtx); 666 else { 667 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 668 lock->lo_name, lock1->li_lock->lo_name); 669 if (!itismychild(lock1->li_lock->lo_witness, w)) 670 mtx_unlock_spin(&w_mtx); 671 } 672 673out: 674#ifdef DDB 675 if (witness_ddb && go_into_ddb) 676 Debugger(__func__); 677#endif /* DDB */ 678 w->w_file = file; 679 w->w_line = line; 680 681 lle = *lock_list; 682 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 683 lle = witness_lock_list_get(); 684 if (lle == NULL) 685 return; 686 lle->ll_next = *lock_list; 687 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 688 td->td_proc->p_pid, lle); 689 *lock_list = lle; 690 } 691 lock1 = &lle->ll_children[lle->ll_count++]; 692 lock1->li_lock = lock; 693 lock1->li_line = line; 694 lock1->li_file = file; 695 if ((flags & LOP_EXCLUSIVE) != 0) 696 lock1->li_flags = LI_EXCLUSIVE; 697 else 698 lock1->li_flags = 0; 699 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 700 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 701} 702 703void 704witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 705{ 706 struct lock_instance *instance; 707 struct lock_class *class; 708 709 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 710 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 711 return; 712 class = lock->lo_class; 713 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 714 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 715 class->lc_name, lock->lo_name, file, line); 716 if ((flags & LOP_TRYLOCK) == 0) 717 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 718 lock->lo_name, file, line); 719 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 720 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 721 class->lc_name, lock->lo_name, file, line); 722 instance = find_instance(curthread->td_sleeplocks, lock); 723 if (instance == NULL) 724 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 725 class->lc_name, lock->lo_name, file, line); 726 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 727 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 728 class->lc_name, lock->lo_name, file, line); 729 if ((instance->li_flags & LI_RECURSEMASK) != 0) 730 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 731 class->lc_name, lock->lo_name, 732 instance->li_flags & LI_RECURSEMASK, file, line); 733 instance->li_flags |= LI_EXCLUSIVE; 734} 735 736void 737witness_downgrade(struct lock_object *lock, int flags, const char *file, 738 int line) 739{ 740 struct lock_instance *instance; 741 struct lock_class *class; 742 743 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 744 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 745 return; 746 class = lock->lo_class; 747 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 748 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 749 class->lc_name, lock->lo_name, file, line); 750 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 751 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 752 class->lc_name, lock->lo_name, file, line); 753 instance = find_instance(curthread->td_sleeplocks, lock); 754 if (instance == NULL) 755 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 756 class->lc_name, lock->lo_name, file, line); 757 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 758 panic("downgrade of shared lock (%s) %s @ %s:%d", 759 class->lc_name, lock->lo_name, file, line); 760 if ((instance->li_flags & LI_RECURSEMASK) != 0) 761 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 762 class->lc_name, lock->lo_name, 763 instance->li_flags & LI_RECURSEMASK, file, line); 764 instance->li_flags &= ~LI_EXCLUSIVE; 765} 766 767void 768witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 769{ 770 struct lock_list_entry **lock_list, *lle; 771 struct lock_instance *instance; 772 struct lock_class *class; 773 struct thread *td; 774 critical_t s; 775 int i, j; 776 777 if (witness_cold || witness_dead || lock->lo_witness == NULL || 778 panicstr != NULL) 779 return; 780 td = curthread; 781 class = lock->lo_class; 782 if (class->lc_flags & LC_SLEEPLOCK) 783 lock_list = &td->td_sleeplocks; 784 else 785 lock_list = PCPU_PTR(spinlocks); 786 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 787 for (i = 0; i < (*lock_list)->ll_count; i++) { 788 instance = &(*lock_list)->ll_children[i]; 789 if (instance->li_lock == lock) { 790 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 791 (flags & LOP_EXCLUSIVE) == 0) { 792 printf( 793 "shared unlock of (%s) %s @ %s:%d\n", 794 class->lc_name, lock->lo_name, 795 file, line); 796 printf( 797 "while exclusively locked from %s:%d\n", 798 instance->li_file, 799 instance->li_line); 800 panic("excl->ushare"); 801 } 802 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 803 (flags & LOP_EXCLUSIVE) != 0) { 804 printf( 805 "exclusive unlock of (%s) %s @ %s:%d\n", 806 class->lc_name, lock->lo_name, 807 file, line); 808 printf( 809 "while share locked from %s:%d\n", 810 instance->li_file, 811 instance->li_line); 812 panic("share->uexcl"); 813 } 814 /* If we are recursed, unrecurse. */ 815 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 816 CTR4(KTR_WITNESS, 817 "%s: pid %d unrecursed on %s r=%d", __func__, 818 td->td_proc->p_pid, 819 instance->li_lock->lo_name, 820 instance->li_flags); 821 instance->li_flags--; 822 return; 823 } 824 s = cpu_critical_enter(); 825 CTR4(KTR_WITNESS, 826 "%s: pid %d removed %s from lle[%d]", __func__, 827 td->td_proc->p_pid, 828 instance->li_lock->lo_name, 829 (*lock_list)->ll_count - 1); 830 (*lock_list)->ll_count--; 831 for (j = i; j < (*lock_list)->ll_count; j++) 832 (*lock_list)->ll_children[j] = 833 (*lock_list)->ll_children[j + 1]; 834 cpu_critical_exit(s); 835 if ((*lock_list)->ll_count == 0) { 836 lle = *lock_list; 837 *lock_list = lle->ll_next; 838 CTR3(KTR_WITNESS, 839 "%s: pid %d removed lle %p", __func__, 840 td->td_proc->p_pid, lle); 841 witness_lock_list_free(lle); 842 } 843 return; 844 } 845 } 846 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 847 file, line); 848} 849 850/* 851 * Warn if any held locks are not sleepable. Note that Giant and the lock 852 * passed in are both special cases since they are both released during the 853 * sleep process and aren't actually held while the thread is asleep. 854 */ 855int 856witness_sleep(int check_only, struct lock_object *lock, const char *file, 857 int line) 858{ 859 struct lock_list_entry **lock_list, *lle; 860 struct lock_instance *lock1; 861 struct thread *td; 862 critical_t savecrit; 863 int i, n; 864 865 if (witness_dead || panicstr != NULL) 866 return (0); 867 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 868 n = 0; 869 /* 870 * Preemption bad because we need PCPU_PTR(spinlocks) to not change. 871 */ 872 savecrit = cpu_critical_enter(); 873 td = curthread; 874 lock_list = &td->td_sleeplocks; 875again: 876 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 877 for (i = lle->ll_count - 1; i >= 0; i--) { 878 lock1 = &lle->ll_children[i]; 879 if (lock1->li_lock == lock || 880 lock1->li_lock == &Giant.mtx_object) 881 continue; 882 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 883 if (check_only == 0) { 884 CTR3(KTR_WITNESS, 885 "pid %d: sleeping with lock (%s) %s held", 886 td->td_proc->p_pid, 887 lock1->li_lock->lo_class->lc_name, 888 lock1->li_lock->lo_name); 889 lock1->li_flags |= LI_SLEPT; 890 } 891 continue; 892 } 893 n++; 894 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 895 file, line, check_only ? "could sleep" : "sleeping", 896 lock1->li_lock->lo_name, lock1->li_file, 897 lock1->li_line); 898 } 899 if (lock_list == &td->td_sleeplocks) { 900 lock_list = PCPU_PTR(spinlocks); 901 goto again; 902 } 903#ifdef DDB 904 if (witness_ddb && n) 905 Debugger(__func__); 906#endif /* DDB */ 907 cpu_critical_exit(savecrit); 908 return (n); 909} 910 911static struct witness * 912enroll(const char *description, struct lock_class *lock_class) 913{ 914 struct witness *w; 915 916 if (!witness_watch || witness_dead || panicstr != NULL) 917 return (NULL); 918 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 919 return (NULL); 920 mtx_lock_spin(&w_mtx); 921 STAILQ_FOREACH(w, &w_all, w_list) { 922 if (strcmp(description, w->w_name) == 0) { 923 w->w_refcount++; 924 mtx_unlock_spin(&w_mtx); 925 if (lock_class != w->w_class) 926 panic( 927 "lock (%s) %s does not match earlier (%s) lock", 928 description, lock_class->lc_name, 929 w->w_class->lc_name); 930 return (w); 931 } 932 } 933 /* 934 * This isn't quite right, as witness_cold is still 0 while we 935 * enroll all the locks initialized before witness_initialize(). 936 */ 937 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 938 mtx_unlock_spin(&w_mtx); 939 panic("spin lock %s not in order list", description); 940 } 941 if ((w = witness_get()) == NULL) 942 return (NULL); 943 w->w_name = description; 944 w->w_class = lock_class; 945 w->w_refcount = 1; 946 STAILQ_INSERT_HEAD(&w_all, w, w_list); 947 if (lock_class->lc_flags & LC_SPINLOCK) 948 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 949 else if (lock_class->lc_flags & LC_SLEEPLOCK) 950 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 951 else { 952 mtx_unlock_spin(&w_mtx); 953 panic("lock class %s is not sleep or spin", 954 lock_class->lc_name); 955 } 956 mtx_unlock_spin(&w_mtx); 957 return (w); 958} 959 960static int 961itismychild(struct witness *parent, struct witness *child) 962{ 963 static int recursed; 964 struct witness_child_list_entry **wcl; 965 struct witness_list *list; 966 967 MPASS(child != NULL && parent != NULL); 968 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 969 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 970 panic( 971 "%s: parent (%s) and child (%s) are not the same lock type", 972 __func__, parent->w_class->lc_name, 973 child->w_class->lc_name); 974 975 /* 976 * Insert "child" after "parent" 977 */ 978 wcl = &parent->w_children; 979 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 980 wcl = &(*wcl)->wcl_next; 981 if (*wcl == NULL) { 982 *wcl = witness_child_get(); 983 if (*wcl == NULL) 984 return (1); 985 } 986 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 987 988 /* 989 * Now prune whole tree. We look for cases where a lock is now 990 * both a descendant and a direct child of a given lock. In that 991 * case, we want to remove the direct child link from the tree. 992 */ 993 if (recursed) 994 return (0); 995 recursed = 1; 996 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 997 list = &w_sleep; 998 else 999 list = &w_spin; 1000 STAILQ_FOREACH(child, list, w_typelist) { 1001 STAILQ_FOREACH(parent, list, w_typelist) { 1002 if (!isitmychild(parent, child)) 1003 continue; 1004 removechild(parent, child); 1005 if (isitmydescendant(parent, child)) 1006 continue; 1007 itismychild(parent, child); 1008 } 1009 } 1010 recursed = 0; 1011 witness_levelall(); 1012 return (0); 1013} 1014 1015static void 1016removechild(struct witness *parent, struct witness *child) 1017{ 1018 struct witness_child_list_entry **wcl, *wcl1; 1019 int i; 1020 1021 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1022 for (i = 0; i < (*wcl)->wcl_count; i++) 1023 if ((*wcl)->wcl_children[i] == child) 1024 goto found; 1025 return; 1026found: 1027 (*wcl)->wcl_count--; 1028 if ((*wcl)->wcl_count > i) 1029 (*wcl)->wcl_children[i] = 1030 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1031 MPASS((*wcl)->wcl_children[i] != NULL); 1032 if ((*wcl)->wcl_count != 0) 1033 return; 1034 wcl1 = *wcl; 1035 *wcl = wcl1->wcl_next; 1036 witness_child_free(wcl1); 1037} 1038 1039static int 1040isitmychild(struct witness *parent, struct witness *child) 1041{ 1042 struct witness_child_list_entry *wcl; 1043 int i; 1044 1045 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1046 for (i = 0; i < wcl->wcl_count; i++) { 1047 if (wcl->wcl_children[i] == child) 1048 return (1); 1049 } 1050 } 1051 return (0); 1052} 1053 1054static int 1055isitmydescendant(struct witness *parent, struct witness *child) 1056{ 1057 struct witness_child_list_entry *wcl; 1058 int i, j; 1059 1060 if (isitmychild(parent, child)) 1061 return (1); 1062 j = 0; 1063 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1064 MPASS(j < 1000); 1065 for (i = 0; i < wcl->wcl_count; i++) { 1066 if (isitmydescendant(wcl->wcl_children[i], child)) 1067 return (1); 1068 } 1069 j++; 1070 } 1071 return (0); 1072} 1073 1074void 1075witness_levelall (void) 1076{ 1077 struct witness_list *list; 1078 struct witness *w, *w1; 1079 1080 /* 1081 * First clear all levels. 1082 */ 1083 STAILQ_FOREACH(w, &w_all, w_list) { 1084 w->w_level = 0; 1085 } 1086 1087 /* 1088 * Look for locks with no parent and level all their descendants. 1089 */ 1090 STAILQ_FOREACH(w, &w_all, w_list) { 1091 /* 1092 * This is just an optimization, technically we could get 1093 * away just walking the all list each time. 1094 */ 1095 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1096 list = &w_sleep; 1097 else 1098 list = &w_spin; 1099 STAILQ_FOREACH(w1, list, w_typelist) { 1100 if (isitmychild(w1, w)) 1101 goto skip; 1102 } 1103 witness_leveldescendents(w, 0); 1104 skip: 1105 } 1106} 1107 1108static void 1109witness_leveldescendents(struct witness *parent, int level) 1110{ 1111 struct witness_child_list_entry *wcl; 1112 int i; 1113 1114 if (parent->w_level < level) 1115 parent->w_level = level; 1116 level++; 1117 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1118 for (i = 0; i < wcl->wcl_count; i++) 1119 witness_leveldescendents(wcl->wcl_children[i], level); 1120} 1121 1122static void 1123witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1124 struct witness *parent) 1125{ 1126 struct witness_child_list_entry *wcl; 1127 int i, level; 1128 1129 level = parent->w_level; 1130 prnt("%-2d", level); 1131 for (i = 0; i < level; i++) 1132 prnt(" "); 1133 prnt("%s", parent->w_name); 1134 if (parent->w_file != NULL) 1135 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1136 parent->w_line); 1137 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1138 for (i = 0; i < wcl->wcl_count; i++) 1139 witness_displaydescendants(prnt, 1140 wcl->wcl_children[i]); 1141} 1142 1143static int 1144dup_ok(struct witness *w) 1145{ 1146 const char **dup; 1147 1148 for (dup = dup_list; *dup != NULL; dup++) 1149 if (strcmp(w->w_name, *dup) == 0) 1150 return (1); 1151 return (0); 1152} 1153 1154static int 1155blessed(struct witness *w1, struct witness *w2) 1156{ 1157 int i; 1158 struct witness_blessed *b; 1159 1160 for (i = 0; i < blessed_count; i++) { 1161 b = &blessed_list[i]; 1162 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1163 if (strcmp(w2->w_name, b->b_lock2) == 0) 1164 return (1); 1165 continue; 1166 } 1167 if (strcmp(w1->w_name, b->b_lock2) == 0) 1168 if (strcmp(w2->w_name, b->b_lock1) == 0) 1169 return (1); 1170 } 1171 return (0); 1172} 1173 1174static struct witness * 1175witness_get(void) 1176{ 1177 struct witness *w; 1178 1179 if (witness_dead) { 1180 mtx_unlock_spin(&w_mtx); 1181 return (NULL); 1182 } 1183 if (STAILQ_EMPTY(&w_free)) { 1184 witness_dead = 1; 1185 mtx_unlock_spin(&w_mtx); 1186 printf("%s: witness exhausted\n", __func__); 1187 return (NULL); 1188 } 1189 w = STAILQ_FIRST(&w_free); 1190 STAILQ_REMOVE_HEAD(&w_free, w_list); 1191 bzero(w, sizeof(*w)); 1192 return (w); 1193} 1194 1195static void 1196witness_free(struct witness *w) 1197{ 1198 1199 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1200} 1201 1202static struct witness_child_list_entry * 1203witness_child_get(void) 1204{ 1205 struct witness_child_list_entry *wcl; 1206 1207 if (witness_dead) { 1208 mtx_unlock_spin(&w_mtx); 1209 return (NULL); 1210 } 1211 wcl = w_child_free; 1212 if (wcl == NULL) { 1213 witness_dead = 1; 1214 mtx_unlock_spin(&w_mtx); 1215 printf("%s: witness exhausted\n", __func__); 1216 return (NULL); 1217 } 1218 w_child_free = wcl->wcl_next; 1219 bzero(wcl, sizeof(*wcl)); 1220 return (wcl); 1221} 1222 1223static void 1224witness_child_free(struct witness_child_list_entry *wcl) 1225{ 1226 1227 wcl->wcl_next = w_child_free; 1228 w_child_free = wcl; 1229} 1230 1231static struct lock_list_entry * 1232witness_lock_list_get(void) 1233{ 1234 struct lock_list_entry *lle; 1235 1236 if (witness_dead) 1237 return (NULL); 1238 mtx_lock_spin(&w_mtx); 1239 lle = w_lock_list_free; 1240 if (lle == NULL) { 1241 witness_dead = 1; 1242 mtx_unlock_spin(&w_mtx); 1243 printf("%s: witness exhausted\n", __func__); 1244 return (NULL); 1245 } 1246 w_lock_list_free = lle->ll_next; 1247 mtx_unlock_spin(&w_mtx); 1248 bzero(lle, sizeof(*lle)); 1249 return (lle); 1250} 1251 1252static void 1253witness_lock_list_free(struct lock_list_entry *lle) 1254{ 1255 1256 mtx_lock_spin(&w_mtx); 1257 lle->ll_next = w_lock_list_free; 1258 w_lock_list_free = lle; 1259 mtx_unlock_spin(&w_mtx); 1260} 1261 1262static struct lock_instance * 1263find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1264{ 1265 struct lock_list_entry *lle; 1266 struct lock_instance *instance; 1267 int i; 1268 1269 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1270 for (i = lle->ll_count - 1; i >= 0; i--) { 1271 instance = &lle->ll_children[i]; 1272 if (instance->li_lock == lock) 1273 return (instance); 1274 } 1275 return (NULL); 1276} 1277 1278int 1279witness_list_locks(struct lock_list_entry **lock_list) 1280{ 1281 struct lock_list_entry *lle; 1282 struct lock_instance *instance; 1283 struct lock_object *lock; 1284 int i, nheld; 1285 1286 nheld = 0; 1287 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1288 for (i = lle->ll_count - 1; i >= 0; i--) { 1289 instance = &lle->ll_children[i]; 1290 lock = instance->li_lock; 1291 printf("%s (%s) %s (%p) locked @ %s:%d\n", 1292 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1293 "exclusive" : "shared", 1294 lock->lo_class->lc_name, lock->lo_name, lock, 1295 instance->li_file, instance->li_line); 1296 nheld++; 1297 } 1298 return (nheld); 1299} 1300 1301/* 1302 * Calling this on td != curthread is bad unless we are in ddb. 1303 */ 1304int 1305witness_list(struct thread *td) 1306{ 1307 critical_t savecrit; 1308 int nheld; 1309 1310 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1311#ifdef DDB 1312 KASSERT(td == curthread || db_active, 1313 ("%s: td != curthread and we aren't in the debugger", __func__)); 1314 if (!db_active && witness_dead) 1315 return (0); 1316#else 1317 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1318 if (witness_dead) 1319 return (0); 1320#endif 1321 nheld = witness_list_locks(&td->td_sleeplocks); 1322 1323 /* 1324 * We only handle spinlocks if td == curthread. This is somewhat broken 1325 * if td is currently executing on some other CPU and holds spin locks 1326 * as we won't display those locks. If we had a MI way of getting 1327 * the per-cpu data for a given cpu then we could use 1328 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1329 * and "fix" this. 1330 */ 1331 if (td == curthread) { 1332 /* 1333 * Preemption bad because we need PCPU_PTR(spinlocks) to not 1334 * change. 1335 */ 1336 savecrit = cpu_critical_enter(); 1337 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1338 cpu_critical_exit(savecrit); 1339 } 1340 return (nheld); 1341} 1342 1343void 1344witness_save(struct lock_object *lock, const char **filep, int *linep) 1345{ 1346 struct lock_instance *instance; 1347 1348 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1349 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1350 return; 1351 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1352 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1353 lock->lo_class->lc_name, lock->lo_name); 1354 instance = find_instance(curthread->td_sleeplocks, lock); 1355 if (instance == NULL) 1356 panic("%s: lock (%s) %s not locked", __func__, 1357 lock->lo_class->lc_name, lock->lo_name); 1358 *filep = instance->li_file; 1359 *linep = instance->li_line; 1360} 1361 1362void 1363witness_restore(struct lock_object *lock, const char *file, int line) 1364{ 1365 struct lock_instance *instance; 1366 1367 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1368 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1369 return; 1370 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1371 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1372 lock->lo_class->lc_name, lock->lo_name); 1373 instance = find_instance(curthread->td_sleeplocks, lock); 1374 if (instance == NULL) 1375 panic("%s: lock (%s) %s not locked", __func__, 1376 lock->lo_class->lc_name, lock->lo_name); 1377 lock->lo_witness->w_file = file; 1378 lock->lo_witness->w_line = line; 1379 instance->li_file = file; 1380 instance->li_line = line; 1381} 1382 1383void 1384witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1385{ 1386#ifdef INVARIANT_SUPPORT 1387 struct lock_instance *instance; 1388 1389 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1390 return; 1391 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1392 instance = find_instance(curthread->td_sleeplocks, lock); 1393 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1394 instance = find_instance(PCPU_GET(spinlocks), lock); 1395 else { 1396 panic("Lock (%s) %s is not sleep or spin!", 1397 lock->lo_class->lc_name, lock->lo_name); 1398 return; 1399 } 1400 switch (flags) { 1401 case LA_UNLOCKED: 1402 if (instance != NULL) 1403 panic("Lock (%s) %s locked @ %s:%d.", 1404 lock->lo_class->lc_name, lock->lo_name, file, line); 1405 break; 1406 case LA_LOCKED: 1407 case LA_LOCKED | LA_RECURSED: 1408 case LA_LOCKED | LA_NOTRECURSED: 1409 case LA_SLOCKED: 1410 case LA_SLOCKED | LA_RECURSED: 1411 case LA_SLOCKED | LA_NOTRECURSED: 1412 case LA_XLOCKED: 1413 case LA_XLOCKED | LA_RECURSED: 1414 case LA_XLOCKED | LA_NOTRECURSED: 1415 if (instance == NULL) { 1416 panic("Lock (%s) %s not locked @ %s:%d.", 1417 lock->lo_class->lc_name, lock->lo_name, file, line); 1418 break; 1419 } 1420 if ((flags & LA_XLOCKED) != 0 && 1421 (instance->li_flags & LI_EXCLUSIVE) == 0) 1422 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1423 lock->lo_class->lc_name, lock->lo_name, file, line); 1424 if ((flags & LA_SLOCKED) != 0 && 1425 (instance->li_flags & LI_EXCLUSIVE) != 0) 1426 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1427 lock->lo_class->lc_name, lock->lo_name, file, line); 1428 if ((flags & LA_RECURSED) != 0 && 1429 (instance->li_flags & LI_RECURSEMASK) == 0) 1430 panic("Lock (%s) %s not recursed @ %s:%d.", 1431 lock->lo_class->lc_name, lock->lo_name, file, line); 1432 if ((flags & LA_NOTRECURSED) != 0 && 1433 (instance->li_flags & LI_RECURSEMASK) != 0) 1434 panic("Lock (%s) %s recursed @ %s:%d.", 1435 lock->lo_class->lc_name, lock->lo_name, file, line); 1436 break; 1437 default: 1438 panic("Invalid lock assertion at %s:%d.", file, line); 1439 1440 } 1441#endif /* INVARIANT_SUPPORT */ 1442} 1443 1444#ifdef DDB 1445 1446DB_SHOW_COMMAND(locks, db_witness_list) 1447{ 1448 struct thread *td; 1449 pid_t pid; 1450 struct proc *p; 1451 1452 if (have_addr) { 1453 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1454 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1455 ((addr >> 16) % 16) * 10000; 1456 /* sx_slock(&allproc_lock); */ 1457 FOREACH_PROC_IN_SYSTEM(p) { 1458 if (p->p_pid == pid) 1459 break; 1460 } 1461 /* sx_sunlock(&allproc_lock); */ 1462 if (p == NULL) { 1463 db_printf("pid %d not found\n", pid); 1464 return; 1465 } 1466 FOREACH_THREAD_IN_PROC(p, td) { 1467 witness_list(td); 1468 } 1469 } else { 1470 td = curthread; 1471 witness_list(td); 1472 } 1473} 1474 1475DB_SHOW_COMMAND(witness, db_witness_display) 1476{ 1477 1478 witness_display(db_printf); 1479} 1480#endif
| 234 NULL 235}; 236 237/* 238 * Pairs of locks which have been blessed 239 * Don't complain about order problems with blessed locks 240 */ 241static struct witness_blessed blessed_list[] = { 242}; 243static int blessed_count = 244 sizeof(blessed_list) / sizeof(struct witness_blessed); 245 246/* 247 * List of all locks in the system. 248 */ 249STAILQ_HEAD(, lock_object) all_locks = STAILQ_HEAD_INITIALIZER(all_locks); 250 251static struct mtx all_mtx = { 252 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 253 "All locks list", /* mtx_object.lo_name */ 254 LO_INITIALIZED, /* mtx_object.lo_flags */ 255 { NULL }, /* mtx_object.lo_list */ 256 NULL }, /* mtx_object.lo_witness */ 257 MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */ 258 TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked), 259 { NULL, NULL } /* mtx_contested */ 260}; 261 262/* 263 * This global is set to 0 once it becomes safe to use the witness code. 264 */ 265static int witness_cold = 1; 266 267/* 268 * Global variables for book keeping. 269 */ 270static int lock_cur_cnt; 271static int lock_max_cnt; 272 273/* 274 * The WITNESS-enabled diagnostic code. 275 */ 276static void 277witness_initialize(void *dummy __unused) 278{ 279 struct lock_object *lock; 280 struct witness_order_list_entry *order; 281 struct witness *w, *w1; 282 int i; 283 284 /* 285 * We have to release Giant before initializing its witness 286 * structure so that WITNESS doesn't get confused. 287 */ 288 mtx_unlock(&Giant); 289 mtx_assert(&Giant, MA_NOTOWNED); 290 291 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 292 STAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 293 mtx_init(&w_mtx, "witness lock", MTX_SPIN | MTX_QUIET | MTX_NOWITNESS); 294 for (i = 0; i < WITNESS_COUNT; i++) 295 witness_free(&w_data[i]); 296 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 297 witness_child_free(&w_childdata[i]); 298 for (i = 0; i < LOCK_CHILDCOUNT; i++) 299 witness_lock_list_free(&w_locklistdata[i]); 300 301 /* First add in all the specified order lists. */ 302 for (order = order_lists; order->w_name != NULL; order++) { 303 w = enroll(order->w_name, order->w_class); 304 if (w == NULL) 305 continue; 306 w->w_file = "order list"; 307 for (order++; order->w_name != NULL; order++) { 308 w1 = enroll(order->w_name, order->w_class); 309 if (w1 == NULL) 310 continue; 311 w1->w_file = "order list"; 312 itismychild(w, w1); 313 w = w1; 314 } 315 } 316 317 /* Iterate through all locks and add them to witness. */ 318 mtx_lock(&all_mtx); 319 STAILQ_FOREACH(lock, &all_locks, lo_list) { 320 if (lock->lo_flags & LO_WITNESS) 321 lock->lo_witness = enroll(lock->lo_name, 322 lock->lo_class); 323 else 324 lock->lo_witness = NULL; 325 } 326 mtx_unlock(&all_mtx); 327 328 /* Mark the witness code as being ready for use. */ 329 atomic_store_rel_int(&witness_cold, 0); 330 331 mtx_lock(&Giant); 332} 333SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 334 335void 336witness_init(struct lock_object *lock) 337{ 338 struct lock_class *class; 339 340 class = lock->lo_class; 341 if (lock->lo_flags & LO_INITIALIZED) 342 panic("%s: lock (%s) %s is already initialized", __func__, 343 class->lc_name, lock->lo_name); 344 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 345 (class->lc_flags & LC_RECURSABLE) == 0) 346 panic("%s: lock (%s) %s can not be recursable", __func__, 347 class->lc_name, lock->lo_name); 348 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 349 (class->lc_flags & LC_SLEEPABLE) == 0) 350 panic("%s: lock (%s) %s can not be sleepable", __func__, 351 class->lc_name, lock->lo_name); 352 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 353 (class->lc_flags & LC_UPGRADABLE) == 0) 354 panic("%s: lock (%s) %s can not be upgradable", __func__, 355 class->lc_name, lock->lo_name); 356 357 mtx_lock(&all_mtx); 358 STAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 359 lock->lo_flags |= LO_INITIALIZED; 360 lock_cur_cnt++; 361 if (lock_cur_cnt > lock_max_cnt) 362 lock_max_cnt = lock_cur_cnt; 363 mtx_unlock(&all_mtx); 364 if (!witness_cold && !witness_dead && panicstr == NULL && 365 (lock->lo_flags & LO_WITNESS) != 0) 366 lock->lo_witness = enroll(lock->lo_name, class); 367 else 368 lock->lo_witness = NULL; 369} 370 371void 372witness_destroy(struct lock_object *lock) 373{ 374 struct witness *w; 375 376 if (witness_cold) 377 panic("lock (%s) %s destroyed while witness_cold", 378 lock->lo_class->lc_name, lock->lo_name); 379 if ((lock->lo_flags & LO_INITIALIZED) == 0) 380 panic("%s: lock (%s) %s is not initialized", __func__, 381 lock->lo_class->lc_name, lock->lo_name); 382 383 /* XXX: need to verify that no one holds the lock */ 384 w = lock->lo_witness; 385 if (w != NULL) { 386 mtx_lock_spin(&w_mtx); 387 w->w_refcount--; 388 if (w->w_refcount == 0) { 389 CTR2(KTR_WITNESS, 390 "%s: marking witness %s as dead", __func__, w->w_name); 391 w->w_name = "(dead)"; 392 w->w_file = "(dead)"; 393 w->w_line = 0; 394 } 395 mtx_unlock_spin(&w_mtx); 396 } 397 398 mtx_lock(&all_mtx); 399 lock_cur_cnt--; 400 STAILQ_REMOVE(&all_locks, lock, lock_object, lo_list); 401 lock->lo_flags &= ~LO_INITIALIZED; 402 mtx_unlock(&all_mtx); 403} 404 405static void 406witness_display_list(void(*prnt)(const char *fmt, ...), 407 struct witness_list *list) 408{ 409 struct witness *w, *w1; 410 int found; 411 412 STAILQ_FOREACH(w, list, w_typelist) { 413 if (w->w_file == NULL) 414 continue; 415 found = 0; 416 STAILQ_FOREACH(w1, list, w_typelist) { 417 if (isitmychild(w1, w)) { 418 found++; 419 break; 420 } 421 } 422 if (found) 423 continue; 424 /* 425 * This lock has no anscestors, display its descendants. 426 */ 427 witness_displaydescendants(prnt, w); 428 } 429} 430 431static void 432witness_display(void(*prnt)(const char *fmt, ...)) 433{ 434 struct witness *w; 435 436 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 437 witness_levelall(); 438 439 /* 440 * First, handle sleep locks which have been acquired at least 441 * once. 442 */ 443 prnt("Sleep locks:\n"); 444 witness_display_list(prnt, &w_sleep); 445 446 /* 447 * Now do spin locks which have been acquired at least once. 448 */ 449 prnt("\nSpin locks:\n"); 450 witness_display_list(prnt, &w_spin); 451 452 /* 453 * Finally, any locks which have not been acquired yet. 454 */ 455 prnt("\nLocks which were never acquired:\n"); 456 STAILQ_FOREACH(w, &w_all, w_list) { 457 if (w->w_file != NULL) 458 continue; 459 prnt("%s\n", w->w_name); 460 } 461} 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 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 || dup_ok(w)) 553 goto out; 554 w->w_same_squawked = 1; 555 printf("acquiring duplicate lock of same type: \"%s\"\n", 556 lock->lo_name); 557 printf(" 1st @ %s:%d\n", lock1->li_file, lock1->li_line); 558 printf(" 2nd @ %s:%d\n", file, line); 559#ifdef DDB 560 go_into_ddb = 1; 561#endif /* DDB */ 562 goto out; 563 } 564 MPASS(!mtx_owned(&w_mtx)); 565 mtx_lock_spin(&w_mtx); 566 /* 567 * If we have a known higher number just say ok 568 */ 569 if (witness_watch > 1 && w->w_level > w1->w_level) { 570 mtx_unlock_spin(&w_mtx); 571 goto out; 572 } 573 if (isitmydescendant(w1, w)) { 574 mtx_unlock_spin(&w_mtx); 575 goto out; 576 } 577 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 578 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 579 580 MPASS(j < WITNESS_COUNT); 581 lock1 = &lle->ll_children[i]; 582 w1 = lock1->li_lock->lo_witness; 583 584 /* 585 * If this lock doesn't undergo witness checking, 586 * then skip it. 587 */ 588 if (w1 == NULL) { 589 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 590 ("lock missing witness structure")); 591 continue; 592 } 593 /* 594 * If we are locking Giant and we slept with this 595 * lock, then skip it. 596 */ 597 if ((lock1->li_flags & LI_SLEPT) != 0 && 598 lock == &Giant.mtx_object) 599 continue; 600 if (!isitmydescendant(w, w1)) 601 continue; 602 /* 603 * We have a lock order violation, check to see if it 604 * is allowed or has already been yelled about. 605 */ 606 mtx_unlock_spin(&w_mtx); 607 if (blessed(w, w1)) 608 goto out; 609 if (lock1->li_lock == &Giant.mtx_object) { 610 if (w1->w_Giant_squawked) 611 goto out; 612 else 613 w1->w_Giant_squawked = 1; 614 } else { 615 if (w1->w_other_squawked) 616 goto out; 617 else 618 w1->w_other_squawked = 1; 619 } 620 /* 621 * Ok, yell about it. 622 */ 623 printf("lock order reversal\n"); 624 /* 625 * Try to locate an earlier lock with 626 * witness w in our list. 627 */ 628 do { 629 lock2 = &lle->ll_children[i]; 630 MPASS(lock2->li_lock != NULL); 631 if (lock2->li_lock->lo_witness == w) 632 break; 633 i--; 634 if (i == 0 && lle->ll_next != NULL) { 635 lle = lle->ll_next; 636 i = lle->ll_count - 1; 637 MPASS(i != 0); 638 } 639 } while (i >= 0); 640 if (i < 0) { 641 printf(" 1st %p %s @ %s:%d\n", lock1->li_lock, 642 lock1->li_lock->lo_name, lock1->li_file, 643 lock1->li_line); 644 printf(" 2nd %p %s @ %s:%d\n", lock, 645 lock->lo_name, file, line); 646 } else { 647 printf(" 1st %p %s @ %s:%d\n", lock2->li_lock, 648 lock2->li_lock->lo_name, lock2->li_file, 649 lock2->li_line); 650 printf(" 2nd %p %s @ %s:%d\n", lock1->li_lock, 651 lock1->li_lock->lo_name, lock1->li_file, 652 lock1->li_line); 653 printf(" 3rd %p %s @ %s:%d\n", lock, 654 lock->lo_name, file, line); 655 } 656#ifdef DDB 657 go_into_ddb = 1; 658#endif /* DDB */ 659 goto out; 660 } 661 } 662 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 663 /* 664 * Don't build a new relationship if we are locking Giant just 665 * after waking up and the previous lock in the list was acquired 666 * prior to blocking. 667 */ 668 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 669 mtx_unlock_spin(&w_mtx); 670 else { 671 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 672 lock->lo_name, lock1->li_lock->lo_name); 673 if (!itismychild(lock1->li_lock->lo_witness, w)) 674 mtx_unlock_spin(&w_mtx); 675 } 676 677out: 678#ifdef DDB 679 if (witness_ddb && go_into_ddb) 680 Debugger(__func__); 681#endif /* DDB */ 682 w->w_file = file; 683 w->w_line = line; 684 685 lle = *lock_list; 686 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 687 lle = witness_lock_list_get(); 688 if (lle == NULL) 689 return; 690 lle->ll_next = *lock_list; 691 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 692 td->td_proc->p_pid, lle); 693 *lock_list = lle; 694 } 695 lock1 = &lle->ll_children[lle->ll_count++]; 696 lock1->li_lock = lock; 697 lock1->li_line = line; 698 lock1->li_file = file; 699 if ((flags & LOP_EXCLUSIVE) != 0) 700 lock1->li_flags = LI_EXCLUSIVE; 701 else 702 lock1->li_flags = 0; 703 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 704 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 705} 706 707void 708witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 709{ 710 struct lock_instance *instance; 711 struct lock_class *class; 712 713 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 714 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 715 return; 716 class = lock->lo_class; 717 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 718 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 719 class->lc_name, lock->lo_name, file, line); 720 if ((flags & LOP_TRYLOCK) == 0) 721 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 722 lock->lo_name, file, line); 723 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 724 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 725 class->lc_name, lock->lo_name, file, line); 726 instance = find_instance(curthread->td_sleeplocks, lock); 727 if (instance == NULL) 728 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 729 class->lc_name, lock->lo_name, file, line); 730 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 731 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 732 class->lc_name, lock->lo_name, file, line); 733 if ((instance->li_flags & LI_RECURSEMASK) != 0) 734 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 735 class->lc_name, lock->lo_name, 736 instance->li_flags & LI_RECURSEMASK, file, line); 737 instance->li_flags |= LI_EXCLUSIVE; 738} 739 740void 741witness_downgrade(struct lock_object *lock, int flags, const char *file, 742 int line) 743{ 744 struct lock_instance *instance; 745 struct lock_class *class; 746 747 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 748 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 749 return; 750 class = lock->lo_class; 751 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 752 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 753 class->lc_name, lock->lo_name, file, line); 754 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 755 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 756 class->lc_name, lock->lo_name, file, line); 757 instance = find_instance(curthread->td_sleeplocks, lock); 758 if (instance == NULL) 759 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 760 class->lc_name, lock->lo_name, file, line); 761 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 762 panic("downgrade of shared lock (%s) %s @ %s:%d", 763 class->lc_name, lock->lo_name, file, line); 764 if ((instance->li_flags & LI_RECURSEMASK) != 0) 765 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 766 class->lc_name, lock->lo_name, 767 instance->li_flags & LI_RECURSEMASK, file, line); 768 instance->li_flags &= ~LI_EXCLUSIVE; 769} 770 771void 772witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 773{ 774 struct lock_list_entry **lock_list, *lle; 775 struct lock_instance *instance; 776 struct lock_class *class; 777 struct thread *td; 778 critical_t s; 779 int i, j; 780 781 if (witness_cold || witness_dead || lock->lo_witness == NULL || 782 panicstr != NULL) 783 return; 784 td = curthread; 785 class = lock->lo_class; 786 if (class->lc_flags & LC_SLEEPLOCK) 787 lock_list = &td->td_sleeplocks; 788 else 789 lock_list = PCPU_PTR(spinlocks); 790 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 791 for (i = 0; i < (*lock_list)->ll_count; i++) { 792 instance = &(*lock_list)->ll_children[i]; 793 if (instance->li_lock == lock) { 794 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 795 (flags & LOP_EXCLUSIVE) == 0) { 796 printf( 797 "shared unlock of (%s) %s @ %s:%d\n", 798 class->lc_name, lock->lo_name, 799 file, line); 800 printf( 801 "while exclusively locked from %s:%d\n", 802 instance->li_file, 803 instance->li_line); 804 panic("excl->ushare"); 805 } 806 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 807 (flags & LOP_EXCLUSIVE) != 0) { 808 printf( 809 "exclusive unlock of (%s) %s @ %s:%d\n", 810 class->lc_name, lock->lo_name, 811 file, line); 812 printf( 813 "while share locked from %s:%d\n", 814 instance->li_file, 815 instance->li_line); 816 panic("share->uexcl"); 817 } 818 /* If we are recursed, unrecurse. */ 819 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 820 CTR4(KTR_WITNESS, 821 "%s: pid %d unrecursed on %s r=%d", __func__, 822 td->td_proc->p_pid, 823 instance->li_lock->lo_name, 824 instance->li_flags); 825 instance->li_flags--; 826 return; 827 } 828 s = cpu_critical_enter(); 829 CTR4(KTR_WITNESS, 830 "%s: pid %d removed %s from lle[%d]", __func__, 831 td->td_proc->p_pid, 832 instance->li_lock->lo_name, 833 (*lock_list)->ll_count - 1); 834 (*lock_list)->ll_count--; 835 for (j = i; j < (*lock_list)->ll_count; j++) 836 (*lock_list)->ll_children[j] = 837 (*lock_list)->ll_children[j + 1]; 838 cpu_critical_exit(s); 839 if ((*lock_list)->ll_count == 0) { 840 lle = *lock_list; 841 *lock_list = lle->ll_next; 842 CTR3(KTR_WITNESS, 843 "%s: pid %d removed lle %p", __func__, 844 td->td_proc->p_pid, lle); 845 witness_lock_list_free(lle); 846 } 847 return; 848 } 849 } 850 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 851 file, line); 852} 853 854/* 855 * Warn if any held locks are not sleepable. Note that Giant and the lock 856 * passed in are both special cases since they are both released during the 857 * sleep process and aren't actually held while the thread is asleep. 858 */ 859int 860witness_sleep(int check_only, struct lock_object *lock, const char *file, 861 int line) 862{ 863 struct lock_list_entry **lock_list, *lle; 864 struct lock_instance *lock1; 865 struct thread *td; 866 critical_t savecrit; 867 int i, n; 868 869 if (witness_dead || panicstr != NULL) 870 return (0); 871 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 872 n = 0; 873 /* 874 * Preemption bad because we need PCPU_PTR(spinlocks) to not change. 875 */ 876 savecrit = cpu_critical_enter(); 877 td = curthread; 878 lock_list = &td->td_sleeplocks; 879again: 880 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 881 for (i = lle->ll_count - 1; i >= 0; i--) { 882 lock1 = &lle->ll_children[i]; 883 if (lock1->li_lock == lock || 884 lock1->li_lock == &Giant.mtx_object) 885 continue; 886 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 887 if (check_only == 0) { 888 CTR3(KTR_WITNESS, 889 "pid %d: sleeping with lock (%s) %s held", 890 td->td_proc->p_pid, 891 lock1->li_lock->lo_class->lc_name, 892 lock1->li_lock->lo_name); 893 lock1->li_flags |= LI_SLEPT; 894 } 895 continue; 896 } 897 n++; 898 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 899 file, line, check_only ? "could sleep" : "sleeping", 900 lock1->li_lock->lo_name, lock1->li_file, 901 lock1->li_line); 902 } 903 if (lock_list == &td->td_sleeplocks) { 904 lock_list = PCPU_PTR(spinlocks); 905 goto again; 906 } 907#ifdef DDB 908 if (witness_ddb && n) 909 Debugger(__func__); 910#endif /* DDB */ 911 cpu_critical_exit(savecrit); 912 return (n); 913} 914 915static struct witness * 916enroll(const char *description, struct lock_class *lock_class) 917{ 918 struct witness *w; 919 920 if (!witness_watch || witness_dead || panicstr != NULL) 921 return (NULL); 922 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 923 return (NULL); 924 mtx_lock_spin(&w_mtx); 925 STAILQ_FOREACH(w, &w_all, w_list) { 926 if (strcmp(description, w->w_name) == 0) { 927 w->w_refcount++; 928 mtx_unlock_spin(&w_mtx); 929 if (lock_class != w->w_class) 930 panic( 931 "lock (%s) %s does not match earlier (%s) lock", 932 description, lock_class->lc_name, 933 w->w_class->lc_name); 934 return (w); 935 } 936 } 937 /* 938 * This isn't quite right, as witness_cold is still 0 while we 939 * enroll all the locks initialized before witness_initialize(). 940 */ 941 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 942 mtx_unlock_spin(&w_mtx); 943 panic("spin lock %s not in order list", description); 944 } 945 if ((w = witness_get()) == NULL) 946 return (NULL); 947 w->w_name = description; 948 w->w_class = lock_class; 949 w->w_refcount = 1; 950 STAILQ_INSERT_HEAD(&w_all, w, w_list); 951 if (lock_class->lc_flags & LC_SPINLOCK) 952 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 953 else if (lock_class->lc_flags & LC_SLEEPLOCK) 954 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 955 else { 956 mtx_unlock_spin(&w_mtx); 957 panic("lock class %s is not sleep or spin", 958 lock_class->lc_name); 959 } 960 mtx_unlock_spin(&w_mtx); 961 return (w); 962} 963 964static int 965itismychild(struct witness *parent, struct witness *child) 966{ 967 static int recursed; 968 struct witness_child_list_entry **wcl; 969 struct witness_list *list; 970 971 MPASS(child != NULL && parent != NULL); 972 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 973 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 974 panic( 975 "%s: parent (%s) and child (%s) are not the same lock type", 976 __func__, parent->w_class->lc_name, 977 child->w_class->lc_name); 978 979 /* 980 * Insert "child" after "parent" 981 */ 982 wcl = &parent->w_children; 983 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 984 wcl = &(*wcl)->wcl_next; 985 if (*wcl == NULL) { 986 *wcl = witness_child_get(); 987 if (*wcl == NULL) 988 return (1); 989 } 990 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 991 992 /* 993 * Now prune whole tree. We look for cases where a lock is now 994 * both a descendant and a direct child of a given lock. In that 995 * case, we want to remove the direct child link from the tree. 996 */ 997 if (recursed) 998 return (0); 999 recursed = 1; 1000 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1001 list = &w_sleep; 1002 else 1003 list = &w_spin; 1004 STAILQ_FOREACH(child, list, w_typelist) { 1005 STAILQ_FOREACH(parent, list, w_typelist) { 1006 if (!isitmychild(parent, child)) 1007 continue; 1008 removechild(parent, child); 1009 if (isitmydescendant(parent, child)) 1010 continue; 1011 itismychild(parent, child); 1012 } 1013 } 1014 recursed = 0; 1015 witness_levelall(); 1016 return (0); 1017} 1018 1019static void 1020removechild(struct witness *parent, struct witness *child) 1021{ 1022 struct witness_child_list_entry **wcl, *wcl1; 1023 int i; 1024 1025 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1026 for (i = 0; i < (*wcl)->wcl_count; i++) 1027 if ((*wcl)->wcl_children[i] == child) 1028 goto found; 1029 return; 1030found: 1031 (*wcl)->wcl_count--; 1032 if ((*wcl)->wcl_count > i) 1033 (*wcl)->wcl_children[i] = 1034 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1035 MPASS((*wcl)->wcl_children[i] != NULL); 1036 if ((*wcl)->wcl_count != 0) 1037 return; 1038 wcl1 = *wcl; 1039 *wcl = wcl1->wcl_next; 1040 witness_child_free(wcl1); 1041} 1042 1043static int 1044isitmychild(struct witness *parent, struct witness *child) 1045{ 1046 struct witness_child_list_entry *wcl; 1047 int i; 1048 1049 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1050 for (i = 0; i < wcl->wcl_count; i++) { 1051 if (wcl->wcl_children[i] == child) 1052 return (1); 1053 } 1054 } 1055 return (0); 1056} 1057 1058static int 1059isitmydescendant(struct witness *parent, struct witness *child) 1060{ 1061 struct witness_child_list_entry *wcl; 1062 int i, j; 1063 1064 if (isitmychild(parent, child)) 1065 return (1); 1066 j = 0; 1067 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1068 MPASS(j < 1000); 1069 for (i = 0; i < wcl->wcl_count; i++) { 1070 if (isitmydescendant(wcl->wcl_children[i], child)) 1071 return (1); 1072 } 1073 j++; 1074 } 1075 return (0); 1076} 1077 1078void 1079witness_levelall (void) 1080{ 1081 struct witness_list *list; 1082 struct witness *w, *w1; 1083 1084 /* 1085 * First clear all levels. 1086 */ 1087 STAILQ_FOREACH(w, &w_all, w_list) { 1088 w->w_level = 0; 1089 } 1090 1091 /* 1092 * Look for locks with no parent and level all their descendants. 1093 */ 1094 STAILQ_FOREACH(w, &w_all, w_list) { 1095 /* 1096 * This is just an optimization, technically we could get 1097 * away just walking the all list each time. 1098 */ 1099 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1100 list = &w_sleep; 1101 else 1102 list = &w_spin; 1103 STAILQ_FOREACH(w1, list, w_typelist) { 1104 if (isitmychild(w1, w)) 1105 goto skip; 1106 } 1107 witness_leveldescendents(w, 0); 1108 skip: 1109 } 1110} 1111 1112static void 1113witness_leveldescendents(struct witness *parent, int level) 1114{ 1115 struct witness_child_list_entry *wcl; 1116 int i; 1117 1118 if (parent->w_level < level) 1119 parent->w_level = level; 1120 level++; 1121 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1122 for (i = 0; i < wcl->wcl_count; i++) 1123 witness_leveldescendents(wcl->wcl_children[i], level); 1124} 1125 1126static void 1127witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1128 struct witness *parent) 1129{ 1130 struct witness_child_list_entry *wcl; 1131 int i, level; 1132 1133 level = parent->w_level; 1134 prnt("%-2d", level); 1135 for (i = 0; i < level; i++) 1136 prnt(" "); 1137 prnt("%s", parent->w_name); 1138 if (parent->w_file != NULL) 1139 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1140 parent->w_line); 1141 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1142 for (i = 0; i < wcl->wcl_count; i++) 1143 witness_displaydescendants(prnt, 1144 wcl->wcl_children[i]); 1145} 1146 1147static int 1148dup_ok(struct witness *w) 1149{ 1150 const char **dup; 1151 1152 for (dup = dup_list; *dup != NULL; dup++) 1153 if (strcmp(w->w_name, *dup) == 0) 1154 return (1); 1155 return (0); 1156} 1157 1158static int 1159blessed(struct witness *w1, struct witness *w2) 1160{ 1161 int i; 1162 struct witness_blessed *b; 1163 1164 for (i = 0; i < blessed_count; i++) { 1165 b = &blessed_list[i]; 1166 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1167 if (strcmp(w2->w_name, b->b_lock2) == 0) 1168 return (1); 1169 continue; 1170 } 1171 if (strcmp(w1->w_name, b->b_lock2) == 0) 1172 if (strcmp(w2->w_name, b->b_lock1) == 0) 1173 return (1); 1174 } 1175 return (0); 1176} 1177 1178static struct witness * 1179witness_get(void) 1180{ 1181 struct witness *w; 1182 1183 if (witness_dead) { 1184 mtx_unlock_spin(&w_mtx); 1185 return (NULL); 1186 } 1187 if (STAILQ_EMPTY(&w_free)) { 1188 witness_dead = 1; 1189 mtx_unlock_spin(&w_mtx); 1190 printf("%s: witness exhausted\n", __func__); 1191 return (NULL); 1192 } 1193 w = STAILQ_FIRST(&w_free); 1194 STAILQ_REMOVE_HEAD(&w_free, w_list); 1195 bzero(w, sizeof(*w)); 1196 return (w); 1197} 1198 1199static void 1200witness_free(struct witness *w) 1201{ 1202 1203 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1204} 1205 1206static struct witness_child_list_entry * 1207witness_child_get(void) 1208{ 1209 struct witness_child_list_entry *wcl; 1210 1211 if (witness_dead) { 1212 mtx_unlock_spin(&w_mtx); 1213 return (NULL); 1214 } 1215 wcl = w_child_free; 1216 if (wcl == NULL) { 1217 witness_dead = 1; 1218 mtx_unlock_spin(&w_mtx); 1219 printf("%s: witness exhausted\n", __func__); 1220 return (NULL); 1221 } 1222 w_child_free = wcl->wcl_next; 1223 bzero(wcl, sizeof(*wcl)); 1224 return (wcl); 1225} 1226 1227static void 1228witness_child_free(struct witness_child_list_entry *wcl) 1229{ 1230 1231 wcl->wcl_next = w_child_free; 1232 w_child_free = wcl; 1233} 1234 1235static struct lock_list_entry * 1236witness_lock_list_get(void) 1237{ 1238 struct lock_list_entry *lle; 1239 1240 if (witness_dead) 1241 return (NULL); 1242 mtx_lock_spin(&w_mtx); 1243 lle = w_lock_list_free; 1244 if (lle == NULL) { 1245 witness_dead = 1; 1246 mtx_unlock_spin(&w_mtx); 1247 printf("%s: witness exhausted\n", __func__); 1248 return (NULL); 1249 } 1250 w_lock_list_free = lle->ll_next; 1251 mtx_unlock_spin(&w_mtx); 1252 bzero(lle, sizeof(*lle)); 1253 return (lle); 1254} 1255 1256static void 1257witness_lock_list_free(struct lock_list_entry *lle) 1258{ 1259 1260 mtx_lock_spin(&w_mtx); 1261 lle->ll_next = w_lock_list_free; 1262 w_lock_list_free = lle; 1263 mtx_unlock_spin(&w_mtx); 1264} 1265 1266static struct lock_instance * 1267find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1268{ 1269 struct lock_list_entry *lle; 1270 struct lock_instance *instance; 1271 int i; 1272 1273 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1274 for (i = lle->ll_count - 1; i >= 0; i--) { 1275 instance = &lle->ll_children[i]; 1276 if (instance->li_lock == lock) 1277 return (instance); 1278 } 1279 return (NULL); 1280} 1281 1282int 1283witness_list_locks(struct lock_list_entry **lock_list) 1284{ 1285 struct lock_list_entry *lle; 1286 struct lock_instance *instance; 1287 struct lock_object *lock; 1288 int i, nheld; 1289 1290 nheld = 0; 1291 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1292 for (i = lle->ll_count - 1; i >= 0; i--) { 1293 instance = &lle->ll_children[i]; 1294 lock = instance->li_lock; 1295 printf("%s (%s) %s (%p) locked @ %s:%d\n", 1296 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1297 "exclusive" : "shared", 1298 lock->lo_class->lc_name, lock->lo_name, lock, 1299 instance->li_file, instance->li_line); 1300 nheld++; 1301 } 1302 return (nheld); 1303} 1304 1305/* 1306 * Calling this on td != curthread is bad unless we are in ddb. 1307 */ 1308int 1309witness_list(struct thread *td) 1310{ 1311 critical_t savecrit; 1312 int nheld; 1313 1314 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1315#ifdef DDB 1316 KASSERT(td == curthread || db_active, 1317 ("%s: td != curthread and we aren't in the debugger", __func__)); 1318 if (!db_active && witness_dead) 1319 return (0); 1320#else 1321 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1322 if (witness_dead) 1323 return (0); 1324#endif 1325 nheld = witness_list_locks(&td->td_sleeplocks); 1326 1327 /* 1328 * We only handle spinlocks if td == curthread. This is somewhat broken 1329 * if td is currently executing on some other CPU and holds spin locks 1330 * as we won't display those locks. If we had a MI way of getting 1331 * the per-cpu data for a given cpu then we could use 1332 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1333 * and "fix" this. 1334 */ 1335 if (td == curthread) { 1336 /* 1337 * Preemption bad because we need PCPU_PTR(spinlocks) to not 1338 * change. 1339 */ 1340 savecrit = cpu_critical_enter(); 1341 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1342 cpu_critical_exit(savecrit); 1343 } 1344 return (nheld); 1345} 1346 1347void 1348witness_save(struct lock_object *lock, const char **filep, int *linep) 1349{ 1350 struct lock_instance *instance; 1351 1352 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1353 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1354 return; 1355 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1356 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1357 lock->lo_class->lc_name, lock->lo_name); 1358 instance = find_instance(curthread->td_sleeplocks, lock); 1359 if (instance == NULL) 1360 panic("%s: lock (%s) %s not locked", __func__, 1361 lock->lo_class->lc_name, lock->lo_name); 1362 *filep = instance->li_file; 1363 *linep = instance->li_line; 1364} 1365 1366void 1367witness_restore(struct lock_object *lock, const char *file, int line) 1368{ 1369 struct lock_instance *instance; 1370 1371 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1372 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1373 return; 1374 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1375 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1376 lock->lo_class->lc_name, lock->lo_name); 1377 instance = find_instance(curthread->td_sleeplocks, lock); 1378 if (instance == NULL) 1379 panic("%s: lock (%s) %s not locked", __func__, 1380 lock->lo_class->lc_name, lock->lo_name); 1381 lock->lo_witness->w_file = file; 1382 lock->lo_witness->w_line = line; 1383 instance->li_file = file; 1384 instance->li_line = line; 1385} 1386 1387void 1388witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1389{ 1390#ifdef INVARIANT_SUPPORT 1391 struct lock_instance *instance; 1392 1393 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1394 return; 1395 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1396 instance = find_instance(curthread->td_sleeplocks, lock); 1397 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1398 instance = find_instance(PCPU_GET(spinlocks), lock); 1399 else { 1400 panic("Lock (%s) %s is not sleep or spin!", 1401 lock->lo_class->lc_name, lock->lo_name); 1402 return; 1403 } 1404 switch (flags) { 1405 case LA_UNLOCKED: 1406 if (instance != NULL) 1407 panic("Lock (%s) %s locked @ %s:%d.", 1408 lock->lo_class->lc_name, lock->lo_name, file, line); 1409 break; 1410 case LA_LOCKED: 1411 case LA_LOCKED | LA_RECURSED: 1412 case LA_LOCKED | LA_NOTRECURSED: 1413 case LA_SLOCKED: 1414 case LA_SLOCKED | LA_RECURSED: 1415 case LA_SLOCKED | LA_NOTRECURSED: 1416 case LA_XLOCKED: 1417 case LA_XLOCKED | LA_RECURSED: 1418 case LA_XLOCKED | LA_NOTRECURSED: 1419 if (instance == NULL) { 1420 panic("Lock (%s) %s not locked @ %s:%d.", 1421 lock->lo_class->lc_name, lock->lo_name, file, line); 1422 break; 1423 } 1424 if ((flags & LA_XLOCKED) != 0 && 1425 (instance->li_flags & LI_EXCLUSIVE) == 0) 1426 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1427 lock->lo_class->lc_name, lock->lo_name, file, line); 1428 if ((flags & LA_SLOCKED) != 0 && 1429 (instance->li_flags & LI_EXCLUSIVE) != 0) 1430 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1431 lock->lo_class->lc_name, lock->lo_name, file, line); 1432 if ((flags & LA_RECURSED) != 0 && 1433 (instance->li_flags & LI_RECURSEMASK) == 0) 1434 panic("Lock (%s) %s not recursed @ %s:%d.", 1435 lock->lo_class->lc_name, lock->lo_name, file, line); 1436 if ((flags & LA_NOTRECURSED) != 0 && 1437 (instance->li_flags & LI_RECURSEMASK) != 0) 1438 panic("Lock (%s) %s recursed @ %s:%d.", 1439 lock->lo_class->lc_name, lock->lo_name, file, line); 1440 break; 1441 default: 1442 panic("Invalid lock assertion at %s:%d.", file, line); 1443 1444 } 1445#endif /* INVARIANT_SUPPORT */ 1446} 1447 1448#ifdef DDB 1449 1450DB_SHOW_COMMAND(locks, db_witness_list) 1451{ 1452 struct thread *td; 1453 pid_t pid; 1454 struct proc *p; 1455 1456 if (have_addr) { 1457 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1458 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1459 ((addr >> 16) % 16) * 10000; 1460 /* sx_slock(&allproc_lock); */ 1461 FOREACH_PROC_IN_SYSTEM(p) { 1462 if (p->p_pid == pid) 1463 break; 1464 } 1465 /* sx_sunlock(&allproc_lock); */ 1466 if (p == NULL) { 1467 db_printf("pid %d not found\n", pid); 1468 return; 1469 } 1470 FOREACH_THREAD_IN_PROC(p, td) { 1471 witness_list(td); 1472 } 1473 } else { 1474 td = curthread; 1475 witness_list(td); 1476 } 1477} 1478 1479DB_SHOW_COMMAND(witness, db_witness_display) 1480{ 1481 1482 witness_display(db_printf); 1483} 1484#endif
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