subr_witness.c revision 91905
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 91905 2002-03-08 18:57:57Z 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 dup_ok(struct witness *); 128static int blessed(struct witness *, struct witness *); 129static void witness_display_list(void(*prnt)(const char *fmt, ...), 130 struct witness_list *list); 131static void witness_displaydescendants(void(*)(const char *fmt, ...), 132 struct witness *); 133static void witness_leveldescendents(struct witness *parent, int level); 134static void witness_levelall(void); 135static struct witness *witness_get(void); 136static void witness_free(struct witness *m); 137static struct witness_child_list_entry *witness_child_get(void); 138static void witness_child_free(struct witness_child_list_entry *wcl); 139static struct lock_list_entry *witness_lock_list_get(void); 140static void witness_lock_list_free(struct lock_list_entry *lle); 141static void witness_display(void(*)(const char *fmt, ...)); 142static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 143 struct lock_object *lock); 144 145MALLOC_DEFINE(M_WITNESS, "witness", "witness structure"); 146 147static int witness_watch = 1; 148TUNABLE_INT("debug.witness_watch", &witness_watch); 149SYSCTL_INT(_debug, OID_AUTO, witness_watch, CTLFLAG_RD, &witness_watch, 0, ""); 150 151#ifdef DDB 152/* 153 * When DDB is enabled and witness_ddb is set to 1, it will cause the system to 154 * drop into kdebug() when: 155 * - a lock heirarchy violation occurs 156 * - locks are held when going to sleep. 157 */ 158#ifdef WITNESS_DDB 159int witness_ddb = 1; 160#else 161int witness_ddb = 0; 162#endif 163TUNABLE_INT("debug.witness_ddb", &witness_ddb); 164SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, ""); 165#endif /* DDB */ 166 167#ifdef WITNESS_SKIPSPIN 168int witness_skipspin = 1; 169#else 170int witness_skipspin = 0; 171#endif 172TUNABLE_INT("debug.witness_skipspin", &witness_skipspin); 173SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0, 174 ""); 175 176static struct mtx w_mtx; 177static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 178static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 179static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 180static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 181static struct witness_child_list_entry *w_child_free = NULL; 182static struct lock_list_entry *w_lock_list_free = NULL; 183static int witness_dead; /* fatal error, probably no memory */ 184 185static struct witness w_data[WITNESS_COUNT]; 186static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 187static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 188 189static struct witness_order_list_entry order_lists[] = { 190 { "Giant", &lock_class_mtx_sleep }, 191 { "pgrpsess", &lock_class_sx }, 192 { "proctree", &lock_class_sx }, 193 { "allproc", &lock_class_sx }, 194 { "process group", &lock_class_mtx_sleep }, 195 { "process lock", &lock_class_mtx_sleep }, 196 { "session", &lock_class_mtx_sleep }, 197 { "uidinfo hash", &lock_class_mtx_sleep }, 198 { "uidinfo struct", &lock_class_mtx_sleep }, 199 { NULL, NULL }, 200 /* 201 * spin locks 202 */ 203#ifdef SMP 204 { "ap boot", &lock_class_mtx_spin }, 205#ifdef __i386__ 206 { "com", &lock_class_mtx_spin }, 207#endif 208#endif 209 { "sio", &lock_class_mtx_spin }, 210#ifdef __i386__ 211 { "cy", &lock_class_mtx_spin }, 212#endif 213 { "ng_node", &lock_class_mtx_spin }, 214 { "ng_worklist", &lock_class_mtx_spin }, 215 { "ithread table lock", &lock_class_mtx_spin }, 216 { "sched lock", &lock_class_mtx_spin }, 217 { "callout", &lock_class_mtx_spin }, 218 /* 219 * leaf locks 220 */ 221 { "allpmaps", &lock_class_mtx_spin }, 222 { "icu", &lock_class_mtx_spin }, 223#ifdef SMP 224 { "smp rendezvous", &lock_class_mtx_spin }, 225#endif 226 { "clk", &lock_class_mtx_spin }, 227 { NULL, NULL }, 228 { NULL, NULL } 229}; 230 231static const char *dup_list[] = { 232 "process lock", 233 "process group", 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 int i, n; 867 868 if (witness_dead || panicstr != NULL) 869 return (0); 870 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 871 n = 0; 872 /* 873 * Preemption bad because we need PCPU_PTR(spinlocks) to not change. 874 */ 875 critical_enter(); 876 td = curthread; 877 lock_list = &td->td_sleeplocks; 878again: 879 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 880 for (i = lle->ll_count - 1; i >= 0; i--) { 881 lock1 = &lle->ll_children[i]; 882 if (lock1->li_lock == lock || 883 lock1->li_lock == &Giant.mtx_object) 884 continue; 885 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 886 if (check_only == 0) { 887 CTR3(KTR_WITNESS, 888 "pid %d: sleeping with lock (%s) %s held", 889 td->td_proc->p_pid, 890 lock1->li_lock->lo_class->lc_name, 891 lock1->li_lock->lo_name); 892 lock1->li_flags |= LI_SLEPT; 893 } 894 continue; 895 } 896 n++; 897 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 898 file, line, check_only ? "could sleep" : "sleeping", 899 lock1->li_lock->lo_name, lock1->li_file, 900 lock1->li_line); 901 } 902 if (lock_list == &td->td_sleeplocks) { 903 lock_list = PCPU_PTR(spinlocks); 904 goto again; 905 } 906#ifdef DDB 907 if (witness_ddb && n) 908 Debugger(__func__); 909#endif /* DDB */ 910 critical_exit(); 911 return (n); 912} 913 914static struct witness * 915enroll(const char *description, struct lock_class *lock_class) 916{ 917 struct witness *w; 918 919 if (!witness_watch || witness_dead || panicstr != NULL) 920 return (NULL); 921 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 922 return (NULL); 923 mtx_lock_spin(&w_mtx); 924 STAILQ_FOREACH(w, &w_all, w_list) { 925 if (strcmp(description, w->w_name) == 0) { 926 w->w_refcount++; 927 mtx_unlock_spin(&w_mtx); 928 if (lock_class != w->w_class) 929 panic( 930 "lock (%s) %s does not match earlier (%s) lock", 931 description, lock_class->lc_name, 932 w->w_class->lc_name); 933 return (w); 934 } 935 } 936 /* 937 * This isn't quite right, as witness_cold is still 0 while we 938 * enroll all the locks initialized before witness_initialize(). 939 */ 940 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 941 mtx_unlock_spin(&w_mtx); 942 panic("spin lock %s not in order list", description); 943 } 944 if ((w = witness_get()) == NULL) 945 return (NULL); 946 w->w_name = description; 947 w->w_class = lock_class; 948 w->w_refcount = 1; 949 STAILQ_INSERT_HEAD(&w_all, w, w_list); 950 if (lock_class->lc_flags & LC_SPINLOCK) 951 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 952 else if (lock_class->lc_flags & LC_SLEEPLOCK) 953 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 954 else { 955 mtx_unlock_spin(&w_mtx); 956 panic("lock class %s is not sleep or spin", 957 lock_class->lc_name); 958 } 959 mtx_unlock_spin(&w_mtx); 960 return (w); 961} 962 963static int 964itismychild(struct witness *parent, struct witness *child) 965{ 966 static int recursed; 967 struct witness_child_list_entry **wcl; 968 struct witness_list *list; 969 970 MPASS(child != NULL && parent != NULL); 971 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 972 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 973 panic( 974 "%s: parent (%s) and child (%s) are not the same lock type", 975 __func__, parent->w_class->lc_name, 976 child->w_class->lc_name); 977 978 /* 979 * Insert "child" after "parent" 980 */ 981 wcl = &parent->w_children; 982 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 983 wcl = &(*wcl)->wcl_next; 984 if (*wcl == NULL) { 985 *wcl = witness_child_get(); 986 if (*wcl == NULL) 987 return (1); 988 } 989 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 990 991 /* 992 * Now prune whole tree. We look for cases where a lock is now 993 * both a descendant and a direct child of a given lock. In that 994 * case, we want to remove the direct child link from the tree. 995 */ 996 if (recursed) 997 return (0); 998 recursed = 1; 999 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1000 list = &w_sleep; 1001 else 1002 list = &w_spin; 1003 STAILQ_FOREACH(child, list, w_typelist) { 1004 STAILQ_FOREACH(parent, list, w_typelist) { 1005 if (!isitmychild(parent, child)) 1006 continue; 1007 removechild(parent, child); 1008 if (isitmydescendant(parent, child)) 1009 continue; 1010 itismychild(parent, child); 1011 } 1012 } 1013 recursed = 0; 1014 witness_levelall(); 1015 return (0); 1016} 1017 1018static void 1019removechild(struct witness *parent, struct witness *child) 1020{ 1021 struct witness_child_list_entry **wcl, *wcl1; 1022 int i; 1023 1024 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1025 for (i = 0; i < (*wcl)->wcl_count; i++) 1026 if ((*wcl)->wcl_children[i] == child) 1027 goto found; 1028 return; 1029found: 1030 (*wcl)->wcl_count--; 1031 if ((*wcl)->wcl_count > i) 1032 (*wcl)->wcl_children[i] = 1033 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1034 MPASS((*wcl)->wcl_children[i] != NULL); 1035 if ((*wcl)->wcl_count != 0) 1036 return; 1037 wcl1 = *wcl; 1038 *wcl = wcl1->wcl_next; 1039 witness_child_free(wcl1); 1040} 1041 1042static int 1043isitmychild(struct witness *parent, struct witness *child) 1044{ 1045 struct witness_child_list_entry *wcl; 1046 int i; 1047 1048 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1049 for (i = 0; i < wcl->wcl_count; i++) { 1050 if (wcl->wcl_children[i] == child) 1051 return (1); 1052 } 1053 } 1054 return (0); 1055} 1056 1057static int 1058isitmydescendant(struct witness *parent, struct witness *child) 1059{ 1060 struct witness_child_list_entry *wcl; 1061 int i, j; 1062 1063 if (isitmychild(parent, child)) 1064 return (1); 1065 j = 0; 1066 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1067 MPASS(j < 1000); 1068 for (i = 0; i < wcl->wcl_count; i++) { 1069 if (isitmydescendant(wcl->wcl_children[i], child)) 1070 return (1); 1071 } 1072 j++; 1073 } 1074 return (0); 1075} 1076 1077void 1078witness_levelall (void) 1079{ 1080 struct witness_list *list; 1081 struct witness *w, *w1; 1082 1083 /* 1084 * First clear all levels. 1085 */ 1086 STAILQ_FOREACH(w, &w_all, w_list) { 1087 w->w_level = 0; 1088 } 1089 1090 /* 1091 * Look for locks with no parent and level all their descendants. 1092 */ 1093 STAILQ_FOREACH(w, &w_all, w_list) { 1094 /* 1095 * This is just an optimization, technically we could get 1096 * away just walking the all list each time. 1097 */ 1098 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1099 list = &w_sleep; 1100 else 1101 list = &w_spin; 1102 STAILQ_FOREACH(w1, list, w_typelist) { 1103 if (isitmychild(w1, w)) 1104 goto skip; 1105 } 1106 witness_leveldescendents(w, 0); 1107 skip: 1108 } 1109} 1110 1111static void 1112witness_leveldescendents(struct witness *parent, int level) 1113{ 1114 struct witness_child_list_entry *wcl; 1115 int i; 1116 1117 if (parent->w_level < level) 1118 parent->w_level = level; 1119 level++; 1120 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1121 for (i = 0; i < wcl->wcl_count; i++) 1122 witness_leveldescendents(wcl->wcl_children[i], level); 1123} 1124 1125static void 1126witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1127 struct witness *parent) 1128{ 1129 struct witness_child_list_entry *wcl; 1130 int i, level; 1131 1132 level = parent->w_level; 1133 prnt("%-2d", level); 1134 for (i = 0; i < level; i++) 1135 prnt(" "); 1136 prnt("%s", parent->w_name); 1137 if (parent->w_file != NULL) 1138 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1139 parent->w_line); 1140 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1141 for (i = 0; i < wcl->wcl_count; i++) 1142 witness_displaydescendants(prnt, 1143 wcl->wcl_children[i]); 1144} 1145 1146static int 1147dup_ok(struct witness *w) 1148{ 1149 const char **dup; 1150 1151 for (dup = dup_list; *dup != NULL; dup++) 1152 if (strcmp(w->w_name, *dup) == 0) 1153 return (1); 1154 return (0); 1155} 1156 1157static int 1158blessed(struct witness *w1, struct witness *w2) 1159{ 1160 int i; 1161 struct witness_blessed *b; 1162 1163 for (i = 0; i < blessed_count; i++) { 1164 b = &blessed_list[i]; 1165 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1166 if (strcmp(w2->w_name, b->b_lock2) == 0) 1167 return (1); 1168 continue; 1169 } 1170 if (strcmp(w1->w_name, b->b_lock2) == 0) 1171 if (strcmp(w2->w_name, b->b_lock1) == 0) 1172 return (1); 1173 } 1174 return (0); 1175} 1176 1177static struct witness * 1178witness_get(void) 1179{ 1180 struct witness *w; 1181 1182 if (witness_dead) { 1183 mtx_unlock_spin(&w_mtx); 1184 return (NULL); 1185 } 1186 if (STAILQ_EMPTY(&w_free)) { 1187 witness_dead = 1; 1188 mtx_unlock_spin(&w_mtx); 1189 printf("%s: witness exhausted\n", __func__); 1190 return (NULL); 1191 } 1192 w = STAILQ_FIRST(&w_free); 1193 STAILQ_REMOVE_HEAD(&w_free, w_list); 1194 bzero(w, sizeof(*w)); 1195 return (w); 1196} 1197 1198static void 1199witness_free(struct witness *w) 1200{ 1201 1202 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1203} 1204 1205static struct witness_child_list_entry * 1206witness_child_get(void) 1207{ 1208 struct witness_child_list_entry *wcl; 1209 1210 if (witness_dead) { 1211 mtx_unlock_spin(&w_mtx); 1212 return (NULL); 1213 } 1214 wcl = w_child_free; 1215 if (wcl == NULL) { 1216 witness_dead = 1; 1217 mtx_unlock_spin(&w_mtx); 1218 printf("%s: witness exhausted\n", __func__); 1219 return (NULL); 1220 } 1221 w_child_free = wcl->wcl_next; 1222 bzero(wcl, sizeof(*wcl)); 1223 return (wcl); 1224} 1225 1226static void 1227witness_child_free(struct witness_child_list_entry *wcl) 1228{ 1229 1230 wcl->wcl_next = w_child_free; 1231 w_child_free = wcl; 1232} 1233 1234static struct lock_list_entry * 1235witness_lock_list_get(void) 1236{ 1237 struct lock_list_entry *lle; 1238 1239 if (witness_dead) 1240 return (NULL); 1241 mtx_lock_spin(&w_mtx); 1242 lle = w_lock_list_free; 1243 if (lle == NULL) { 1244 witness_dead = 1; 1245 mtx_unlock_spin(&w_mtx); 1246 printf("%s: witness exhausted\n", __func__); 1247 return (NULL); 1248 } 1249 w_lock_list_free = lle->ll_next; 1250 mtx_unlock_spin(&w_mtx); 1251 bzero(lle, sizeof(*lle)); 1252 return (lle); 1253} 1254 1255static void 1256witness_lock_list_free(struct lock_list_entry *lle) 1257{ 1258 1259 mtx_lock_spin(&w_mtx); 1260 lle->ll_next = w_lock_list_free; 1261 w_lock_list_free = lle; 1262 mtx_unlock_spin(&w_mtx); 1263} 1264 1265static struct lock_instance * 1266find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1267{ 1268 struct lock_list_entry *lle; 1269 struct lock_instance *instance; 1270 int i; 1271 1272 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1273 for (i = lle->ll_count - 1; i >= 0; i--) { 1274 instance = &lle->ll_children[i]; 1275 if (instance->li_lock == lock) 1276 return (instance); 1277 } 1278 return (NULL); 1279} 1280 1281int 1282witness_list_locks(struct lock_list_entry **lock_list) 1283{ 1284 struct lock_list_entry *lle; 1285 struct lock_instance *instance; 1286 struct lock_object *lock; 1287 int i, nheld; 1288 1289 nheld = 0; 1290 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1291 for (i = lle->ll_count - 1; i >= 0; i--) { 1292 instance = &lle->ll_children[i]; 1293 lock = instance->li_lock; 1294 printf("%s (%s) %s (%p) locked @ %s:%d\n", 1295 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1296 "exclusive" : "shared", 1297 lock->lo_class->lc_name, lock->lo_name, lock, 1298 instance->li_file, instance->li_line); 1299 nheld++; 1300 } 1301 return (nheld); 1302} 1303 1304/* 1305 * Calling this on td != curthread is bad unless we are in ddb. 1306 */ 1307int 1308witness_list(struct thread *td) 1309{ 1310 int nheld; 1311 1312 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1313#ifdef DDB 1314 KASSERT(td == curthread || db_active, 1315 ("%s: td != curthread and we aren't in the debugger", __func__)); 1316 if (!db_active && witness_dead) 1317 return (0); 1318#else 1319 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1320 if (witness_dead) 1321 return (0); 1322#endif 1323 nheld = witness_list_locks(&td->td_sleeplocks); 1324 1325 /* 1326 * We only handle spinlocks if td == curthread. This is somewhat broken 1327 * if td is currently executing on some other CPU and holds spin locks 1328 * as we won't display those locks. If we had a MI way of getting 1329 * the per-cpu data for a given cpu then we could use 1330 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1331 * and "fix" this. 1332 * 1333 * That still wouldn't really fix this unless we locked sched_lock 1334 * or stopped the other CPU to make sure it wasn't changing the list 1335 * out from under us. It is probably best to just not try to handle 1336 * threads on other CPU's for now. 1337 */ 1338 if (td == curthread) { 1339 /* 1340 * Preemption bad because we need PCPU_PTR(spinlocks) to not 1341 * change. 1342 */ 1343 critical_enter(); 1344 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1345 critical_exit(); 1346 } 1347 return (nheld); 1348} 1349 1350void 1351witness_save(struct lock_object *lock, const char **filep, int *linep) 1352{ 1353 struct lock_instance *instance; 1354 1355 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1356 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1357 return; 1358 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1359 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1360 lock->lo_class->lc_name, lock->lo_name); 1361 instance = find_instance(curthread->td_sleeplocks, lock); 1362 if (instance == NULL) 1363 panic("%s: lock (%s) %s not locked", __func__, 1364 lock->lo_class->lc_name, lock->lo_name); 1365 *filep = instance->li_file; 1366 *linep = instance->li_line; 1367} 1368 1369void 1370witness_restore(struct lock_object *lock, const char *file, int line) 1371{ 1372 struct lock_instance *instance; 1373 1374 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1375 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1376 return; 1377 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1378 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1379 lock->lo_class->lc_name, lock->lo_name); 1380 instance = find_instance(curthread->td_sleeplocks, lock); 1381 if (instance == NULL) 1382 panic("%s: lock (%s) %s not locked", __func__, 1383 lock->lo_class->lc_name, lock->lo_name); 1384 lock->lo_witness->w_file = file; 1385 lock->lo_witness->w_line = line; 1386 instance->li_file = file; 1387 instance->li_line = line; 1388} 1389 1390void 1391witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1392{ 1393#ifdef INVARIANT_SUPPORT 1394 struct lock_instance *instance; 1395 1396 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1397 return; 1398 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1399 instance = find_instance(curthread->td_sleeplocks, lock); 1400 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1401 instance = find_instance(PCPU_GET(spinlocks), lock); 1402 else { 1403 panic("Lock (%s) %s is not sleep or spin!", 1404 lock->lo_class->lc_name, lock->lo_name); 1405 return; 1406 } 1407 switch (flags) { 1408 case LA_UNLOCKED: 1409 if (instance != NULL) 1410 panic("Lock (%s) %s locked @ %s:%d.", 1411 lock->lo_class->lc_name, lock->lo_name, file, line); 1412 break; 1413 case LA_LOCKED: 1414 case LA_LOCKED | LA_RECURSED: 1415 case LA_LOCKED | LA_NOTRECURSED: 1416 case LA_SLOCKED: 1417 case LA_SLOCKED | LA_RECURSED: 1418 case LA_SLOCKED | LA_NOTRECURSED: 1419 case LA_XLOCKED: 1420 case LA_XLOCKED | LA_RECURSED: 1421 case LA_XLOCKED | LA_NOTRECURSED: 1422 if (instance == NULL) { 1423 panic("Lock (%s) %s not locked @ %s:%d.", 1424 lock->lo_class->lc_name, lock->lo_name, file, line); 1425 break; 1426 } 1427 if ((flags & LA_XLOCKED) != 0 && 1428 (instance->li_flags & LI_EXCLUSIVE) == 0) 1429 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1430 lock->lo_class->lc_name, lock->lo_name, file, line); 1431 if ((flags & LA_SLOCKED) != 0 && 1432 (instance->li_flags & LI_EXCLUSIVE) != 0) 1433 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1434 lock->lo_class->lc_name, lock->lo_name, file, line); 1435 if ((flags & LA_RECURSED) != 0 && 1436 (instance->li_flags & LI_RECURSEMASK) == 0) 1437 panic("Lock (%s) %s not recursed @ %s:%d.", 1438 lock->lo_class->lc_name, lock->lo_name, file, line); 1439 if ((flags & LA_NOTRECURSED) != 0 && 1440 (instance->li_flags & LI_RECURSEMASK) != 0) 1441 panic("Lock (%s) %s recursed @ %s:%d.", 1442 lock->lo_class->lc_name, lock->lo_name, file, line); 1443 break; 1444 default: 1445 panic("Invalid lock assertion at %s:%d.", file, line); 1446 1447 } 1448#endif /* INVARIANT_SUPPORT */ 1449} 1450 1451#ifdef DDB 1452 1453DB_SHOW_COMMAND(locks, db_witness_list) 1454{ 1455 struct thread *td; 1456 pid_t pid; 1457 struct proc *p; 1458 1459 if (have_addr) { 1460 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1461 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1462 ((addr >> 16) % 16) * 10000; 1463 /* sx_slock(&allproc_lock); */ 1464 FOREACH_PROC_IN_SYSTEM(p) { 1465 if (p->p_pid == pid) 1466 break; 1467 } 1468 /* sx_sunlock(&allproc_lock); */ 1469 if (p == NULL) { 1470 db_printf("pid %d not found\n", pid); 1471 return; 1472 } 1473 FOREACH_THREAD_IN_PROC(p, td) { 1474 witness_list(td); 1475 } 1476 } else { 1477 td = curthread; 1478 witness_list(td); 1479 } 1480} 1481 1482DB_SHOW_COMMAND(witness, db_witness_display) 1483{ 1484 1485 witness_display(db_printf); 1486} 1487#endif 1488