subr_witness.c revision 94857
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 94857 2002-04-16 17:03:05Z jhb $ 31 */ 32 33/* 34 * Implementation of the `witness' lock verifier. Originally implemented for 35 * mutexes in BSD/OS. Extended to handle generic lock objects and lock 36 * classes in FreeBSD. 37 */ 38 39/* 40 * Main Entry: witness 41 * Pronunciation: 'wit-n&s 42 * Function: noun 43 * Etymology: Middle English witnesse, from Old English witnes knowledge, 44 * testimony, witness, from 2wit 45 * Date: before 12th century 46 * 1 : attestation of a fact or event : TESTIMONY 47 * 2 : one that gives evidence; specifically : one who testifies in 48 * a cause or before a judicial tribunal 49 * 3 : one asked to be present at a transaction so as to be able to 50 * testify to its having taken place 51 * 4 : one who has personal knowledge of something 52 * 5 a : something serving as evidence or proof : SIGN 53 * b : public affirmation by word or example of usually 54 * religious faith or conviction <the heroic witness to divine 55 * life -- Pilot> 56 * 6 capitalized : a member of the Jehovah's Witnesses 57 */ 58 59#include "opt_ddb.h" 60#include "opt_witness.h" 61 62#include <sys/param.h> 63#include <sys/bus.h> 64#include <sys/kernel.h> 65#include <sys/ktr.h> 66#include <sys/lock.h> 67#include <sys/malloc.h> 68#include <sys/mutex.h> 69#include <sys/proc.h> 70#include <sys/sysctl.h> 71#include <sys/systm.h> 72 73#include <ddb/ddb.h> 74 75#define WITNESS_COUNT 200 76#define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4) 77/* 78 * XXX: This is somewhat bogus, as we assume here that at most 1024 threads 79 * will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should 80 * probably be safe for the most part, but it's still a SWAG. 81 */ 82#define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2 83 84#define WITNESS_NCHILDREN 6 85 86struct witness_child_list_entry; 87 88struct witness { 89 const char *w_name; 90 struct lock_class *w_class; 91 STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */ 92 STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ 93 struct witness_child_list_entry *w_children; /* Great evilness... */ 94 const char *w_file; 95 int w_line; 96 u_int w_level; 97 u_int w_refcount; 98 u_char w_Giant_squawked:1; 99 u_char w_other_squawked:1; 100 u_char w_same_squawked:1; 101}; 102 103struct witness_child_list_entry { 104 struct witness_child_list_entry *wcl_next; 105 struct witness *wcl_children[WITNESS_NCHILDREN]; 106 u_int wcl_count; 107}; 108 109STAILQ_HEAD(witness_list, witness); 110 111struct witness_blessed { 112 const char *b_lock1; 113 const char *b_lock2; 114}; 115 116struct witness_order_list_entry { 117 const char *w_name; 118 struct lock_class *w_class; 119}; 120 121static struct witness *enroll(const char *description, 122 struct lock_class *lock_class); 123static int itismychild(struct witness *parent, struct witness *child); 124static void removechild(struct witness *parent, struct witness *child); 125static int isitmychild(struct witness *parent, struct witness *child); 126static int isitmydescendant(struct witness *parent, struct witness *child); 127static int blessed(struct witness *, struct witness *); 128static void witness_display_list(void(*prnt)(const char *fmt, ...), 129 struct witness_list *list); 130static void witness_displaydescendants(void(*)(const char *fmt, ...), 131 struct witness *); 132static void witness_leveldescendents(struct witness *parent, int level); 133static void witness_levelall(void); 134static struct witness *witness_get(void); 135static void witness_free(struct witness *m); 136static struct witness_child_list_entry *witness_child_get(void); 137static void witness_child_free(struct witness_child_list_entry *wcl); 138static struct lock_list_entry *witness_lock_list_get(void); 139static void witness_lock_list_free(struct lock_list_entry *lle); 140static void witness_display(void(*)(const char *fmt, ...)); 141static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 142 struct lock_object *lock); 143 144MALLOC_DEFINE(M_WITNESS, "witness", "witness structure"); 145 146static int witness_watch = 1; 147TUNABLE_INT("debug.witness_watch", &witness_watch); 148SYSCTL_INT(_debug, OID_AUTO, witness_watch, CTLFLAG_RD, &witness_watch, 0, ""); 149 150#ifdef DDB 151/* 152 * When DDB is enabled and witness_ddb is set to 1, it will cause the system to 153 * drop into kdebug() when: 154 * - a lock heirarchy violation occurs 155 * - locks are held when going to sleep. 156 */ 157#ifdef WITNESS_DDB 158int witness_ddb = 1; 159#else 160int witness_ddb = 0; 161#endif 162TUNABLE_INT("debug.witness_ddb", &witness_ddb); 163SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, ""); 164#endif /* DDB */ 165 166#ifdef WITNESS_SKIPSPIN 167int witness_skipspin = 1; 168#else 169int witness_skipspin = 0; 170#endif 171TUNABLE_INT("debug.witness_skipspin", &witness_skipspin); 172SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0, 173 ""); 174 175static struct mtx w_mtx; 176static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 177static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 178static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 179static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 180static struct witness_child_list_entry *w_child_free = NULL; 181static struct lock_list_entry *w_lock_list_free = NULL; 182static int witness_dead; /* fatal error, probably no memory */ 183 184static struct witness w_data[WITNESS_COUNT]; 185static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 186static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 187 188static struct witness_order_list_entry order_lists[] = { 189 { "Giant", &lock_class_mtx_sleep }, 190 { "proctree", &lock_class_sx }, 191 { "allproc", &lock_class_sx }, 192 { "process group", &lock_class_mtx_sleep }, 193 { "process lock", &lock_class_mtx_sleep }, 194 { "session", &lock_class_mtx_sleep }, 195 { "uidinfo hash", &lock_class_mtx_sleep }, 196 { "uidinfo struct", &lock_class_mtx_sleep }, 197 { NULL, NULL }, 198 /* 199 * spin locks 200 */ 201#ifdef SMP 202 { "ap boot", &lock_class_mtx_spin }, 203#ifdef __i386__ 204 { "com", &lock_class_mtx_spin }, 205#endif 206#endif 207 { "sio", &lock_class_mtx_spin }, 208#ifdef __i386__ 209 { "cy", &lock_class_mtx_spin }, 210#endif 211 { "ng_node", &lock_class_mtx_spin }, 212 { "ng_worklist", &lock_class_mtx_spin }, 213 { "ithread table lock", &lock_class_mtx_spin }, 214 { "sched lock", &lock_class_mtx_spin }, 215 { "callout", &lock_class_mtx_spin }, 216 /* 217 * leaf locks 218 */ 219 { "allpmaps", &lock_class_mtx_spin }, 220 { "icu", &lock_class_mtx_spin }, 221#ifdef SMP 222 { "smp rendezvous", &lock_class_mtx_spin }, 223#endif 224 { "clk", &lock_class_mtx_spin }, 225 { NULL, NULL }, 226 { NULL, NULL } 227}; 228 229/* 230 * Pairs of locks which have been blessed 231 * Don't complain about order problems with blessed locks 232 */ 233static struct witness_blessed blessed_list[] = { 234}; 235static int blessed_count = 236 sizeof(blessed_list) / sizeof(struct witness_blessed); 237 238/* 239 * List of all locks in the system. 240 */ 241STAILQ_HEAD(, lock_object) all_locks = STAILQ_HEAD_INITIALIZER(all_locks); 242 243static struct mtx all_mtx = { 244 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 245 "All locks list", /* mtx_object.lo_name */ 246 "All locks list", /* mtx_object.lo_type */ 247 LO_INITIALIZED, /* mtx_object.lo_flags */ 248 { NULL }, /* mtx_object.lo_list */ 249 NULL }, /* mtx_object.lo_witness */ 250 MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */ 251 TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked), 252 { NULL, NULL } /* mtx_contested */ 253}; 254 255/* 256 * This global is set to 0 once it becomes safe to use the witness code. 257 */ 258static int witness_cold = 1; 259 260/* 261 * Global variables for book keeping. 262 */ 263static int lock_cur_cnt; 264static int lock_max_cnt; 265 266/* 267 * The WITNESS-enabled diagnostic code. 268 */ 269static void 270witness_initialize(void *dummy __unused) 271{ 272 struct lock_object *lock; 273 struct witness_order_list_entry *order; 274 struct witness *w, *w1; 275 int i; 276 277 /* 278 * We have to release Giant before initializing its witness 279 * structure so that WITNESS doesn't get confused. 280 */ 281 mtx_unlock(&Giant); 282 mtx_assert(&Giant, MA_NOTOWNED); 283 284 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 285 STAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 286 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 287 MTX_NOWITNESS); 288 for (i = 0; i < WITNESS_COUNT; i++) 289 witness_free(&w_data[i]); 290 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 291 witness_child_free(&w_childdata[i]); 292 for (i = 0; i < LOCK_CHILDCOUNT; i++) 293 witness_lock_list_free(&w_locklistdata[i]); 294 295 /* First add in all the specified order lists. */ 296 for (order = order_lists; order->w_name != NULL; order++) { 297 w = enroll(order->w_name, order->w_class); 298 if (w == NULL) 299 continue; 300 w->w_file = "order list"; 301 for (order++; order->w_name != NULL; order++) { 302 w1 = enroll(order->w_name, order->w_class); 303 if (w1 == NULL) 304 continue; 305 w1->w_file = "order list"; 306 itismychild(w, w1); 307 w = w1; 308 } 309 } 310 311 /* Iterate through all locks and add them to witness. */ 312 mtx_lock(&all_mtx); 313 STAILQ_FOREACH(lock, &all_locks, lo_list) { 314 if (lock->lo_flags & LO_WITNESS) 315 lock->lo_witness = enroll(lock->lo_type, 316 lock->lo_class); 317 else 318 lock->lo_witness = NULL; 319 } 320 mtx_unlock(&all_mtx); 321 322 /* Mark the witness code as being ready for use. */ 323 atomic_store_rel_int(&witness_cold, 0); 324 325 mtx_lock(&Giant); 326} 327SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 328 329void 330witness_init(struct lock_object *lock) 331{ 332 struct lock_class *class; 333 334 class = lock->lo_class; 335 if (lock->lo_flags & LO_INITIALIZED) 336 panic("%s: lock (%s) %s is already initialized", __func__, 337 class->lc_name, lock->lo_name); 338 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 339 (class->lc_flags & LC_RECURSABLE) == 0) 340 panic("%s: lock (%s) %s can not be recursable", __func__, 341 class->lc_name, lock->lo_name); 342 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 343 (class->lc_flags & LC_SLEEPABLE) == 0) 344 panic("%s: lock (%s) %s can not be sleepable", __func__, 345 class->lc_name, lock->lo_name); 346 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 347 (class->lc_flags & LC_UPGRADABLE) == 0) 348 panic("%s: lock (%s) %s can not be upgradable", __func__, 349 class->lc_name, lock->lo_name); 350 351 mtx_lock(&all_mtx); 352 STAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 353 lock->lo_flags |= LO_INITIALIZED; 354 lock_cur_cnt++; 355 if (lock_cur_cnt > lock_max_cnt) 356 lock_max_cnt = lock_cur_cnt; 357 mtx_unlock(&all_mtx); 358 if (!witness_cold && !witness_dead && panicstr == NULL && 359 (lock->lo_flags & LO_WITNESS) != 0) 360 lock->lo_witness = enroll(lock->lo_type, class); 361 else 362 lock->lo_witness = NULL; 363} 364 365void 366witness_destroy(struct lock_object *lock) 367{ 368 struct witness *w; 369 370 if (witness_cold) 371 panic("lock (%s) %s destroyed while witness_cold", 372 lock->lo_class->lc_name, lock->lo_name); 373 if ((lock->lo_flags & LO_INITIALIZED) == 0) 374 panic("%s: lock (%s) %s is not initialized", __func__, 375 lock->lo_class->lc_name, lock->lo_name); 376 377 /* XXX: need to verify that no one holds the lock */ 378 w = lock->lo_witness; 379 if (w != NULL) { 380 mtx_lock_spin(&w_mtx); 381 w->w_refcount--; 382 if (w->w_refcount == 0) { 383 CTR2(KTR_WITNESS, 384 "%s: marking witness %s as dead", __func__, w->w_name); 385 w->w_name = "(dead)"; 386 w->w_file = "(dead)"; 387 w->w_line = 0; 388 } 389 mtx_unlock_spin(&w_mtx); 390 } 391 392 mtx_lock(&all_mtx); 393 lock_cur_cnt--; 394 STAILQ_REMOVE(&all_locks, lock, lock_object, lo_list); 395 lock->lo_flags &= ~LO_INITIALIZED; 396 mtx_unlock(&all_mtx); 397} 398 399static void 400witness_display_list(void(*prnt)(const char *fmt, ...), 401 struct witness_list *list) 402{ 403 struct witness *w, *w1; 404 int found; 405 406 STAILQ_FOREACH(w, list, w_typelist) { 407 if (w->w_file == NULL) 408 continue; 409 found = 0; 410 STAILQ_FOREACH(w1, list, w_typelist) { 411 if (isitmychild(w1, w)) { 412 found++; 413 break; 414 } 415 } 416 if (found) 417 continue; 418 /* 419 * This lock has no anscestors, display its descendants. 420 */ 421 witness_displaydescendants(prnt, w); 422 } 423} 424 425static void 426witness_display(void(*prnt)(const char *fmt, ...)) 427{ 428 struct witness *w; 429 430 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 431 witness_levelall(); 432 433 /* 434 * First, handle sleep locks which have been acquired at least 435 * once. 436 */ 437 prnt("Sleep locks:\n"); 438 witness_display_list(prnt, &w_sleep); 439 440 /* 441 * Now do spin locks which have been acquired at least once. 442 */ 443 prnt("\nSpin locks:\n"); 444 witness_display_list(prnt, &w_spin); 445 446 /* 447 * Finally, any locks which have not been acquired yet. 448 */ 449 prnt("\nLocks which were never acquired:\n"); 450 STAILQ_FOREACH(w, &w_all, w_list) { 451 if (w->w_file != NULL) 452 continue; 453 prnt("%s\n", w->w_name); 454 } 455} 456 457void 458witness_lock(struct lock_object *lock, int flags, const char *file, int line) 459{ 460 struct lock_list_entry **lock_list, *lle; 461 struct lock_instance *lock1, *lock2; 462 struct lock_class *class; 463 struct witness *w, *w1; 464 struct thread *td; 465 int i, j; 466#ifdef DDB 467 int go_into_ddb = 0; 468#endif /* DDB */ 469 470 if (witness_cold || witness_dead || lock->lo_witness == NULL || 471 panicstr != NULL) 472 return; 473 w = lock->lo_witness; 474 class = lock->lo_class; 475 td = curthread; 476 477 if (class->lc_flags & LC_SLEEPLOCK) { 478 /* 479 * Since spin locks include a critical section, this check 480 * impliclty enforces a lock order of all sleep locks before 481 * all spin locks. 482 */ 483 if (td->td_critnest != 0 && (flags & LOP_TRYLOCK) == 0) 484 panic("blockable sleep lock (%s) %s @ %s:%d", 485 class->lc_name, lock->lo_name, file, line); 486 lock_list = &td->td_sleeplocks; 487 } else 488 lock_list = PCPU_PTR(spinlocks); 489 490 /* 491 * Try locks do not block if they fail to acquire the lock, thus 492 * there is no danger of deadlocks or of switching while holding a 493 * spin lock if we acquire a lock via a try operation. 494 */ 495 if (flags & LOP_TRYLOCK) 496 goto out; 497 498 /* 499 * Is this the first lock acquired? If so, then no order checking 500 * is needed. 501 */ 502 if (*lock_list == NULL) 503 goto out; 504 505 /* 506 * Check to see if we are recursing on a lock we already own. 507 */ 508 lock1 = find_instance(*lock_list, lock); 509 if (lock1 != NULL) { 510 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 511 (flags & LOP_EXCLUSIVE) == 0) { 512 printf("shared lock of (%s) %s @ %s:%d\n", 513 class->lc_name, lock->lo_name, file, line); 514 printf("while exclusively locked from %s:%d\n", 515 lock1->li_file, lock1->li_line); 516 panic("share->excl"); 517 } 518 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 519 (flags & LOP_EXCLUSIVE) != 0) { 520 printf("exclusive lock of (%s) %s @ %s:%d\n", 521 class->lc_name, lock->lo_name, file, line); 522 printf("while share locked from %s:%d\n", 523 lock1->li_file, lock1->li_line); 524 panic("excl->share"); 525 } 526 lock1->li_flags++; 527 if ((lock->lo_flags & LO_RECURSABLE) == 0) { 528 printf( 529 "recursed on non-recursive lock (%s) %s @ %s:%d\n", 530 class->lc_name, lock->lo_name, file, line); 531 printf("first acquired @ %s:%d\n", lock1->li_file, 532 lock1->li_line); 533 panic("recurse"); 534 } 535 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 536 td->td_proc->p_pid, lock->lo_name, 537 lock1->li_flags & LI_RECURSEMASK); 538 lock1->li_file = file; 539 lock1->li_line = line; 540 return; 541 } 542 543 /* 544 * Check for duplicate locks of the same type. Note that we only 545 * have to check for this on the last lock we just acquired. Any 546 * other cases will be caught as lock order violations. 547 */ 548 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 549 w1 = lock1->li_lock->lo_witness; 550 if (w1 == w) { 551 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK)) 552 goto out; 553 w->w_same_squawked = 1; 554 printf("acquiring duplicate lock of same type: \"%s\"\n", 555 lock->lo_type); 556 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 557 lock1->li_file, lock1->li_line); 558 printf(" 2nd %s @ %s:%d\n", lock->lo_name, 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 /* 601 * If we are locking a sleepable lock and this lock 602 * isn't sleepable and isn't Giant, we want to treat 603 * it as a lock order violation to enfore a general 604 * lock order of sleepable locks before non-sleepable 605 * locks. Thus, we only bother checking the lock 606 * order hierarchy if we pass the initial test. 607 */ 608 if (!((lock->lo_flags & LO_SLEEPABLE) != 0 && 609 ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && 610 lock1->li_lock != &Giant.mtx_object)) && 611 !isitmydescendant(w, w1)) 612 continue; 613 /* 614 * We have a lock order violation, check to see if it 615 * is allowed or has already been yelled about. 616 */ 617 mtx_unlock_spin(&w_mtx); 618 if (blessed(w, w1)) 619 goto out; 620 if (lock1->li_lock == &Giant.mtx_object) { 621 if (w1->w_Giant_squawked) 622 goto out; 623 else 624 w1->w_Giant_squawked = 1; 625 } else { 626 if (w1->w_other_squawked) 627 goto out; 628 else 629 w1->w_other_squawked = 1; 630 } 631 /* 632 * Ok, yell about it. 633 */ 634 printf("lock order reversal\n"); 635 /* 636 * Try to locate an earlier lock with 637 * witness w in our list. 638 */ 639 do { 640 lock2 = &lle->ll_children[i]; 641 MPASS(lock2->li_lock != NULL); 642 if (lock2->li_lock->lo_witness == w) 643 break; 644 i--; 645 if (i == 0 && lle->ll_next != NULL) { 646 lle = lle->ll_next; 647 i = lle->ll_count - 1; 648 MPASS(i != 0); 649 } 650 } while (i >= 0); 651 if (i < 0) { 652 printf(" 1st %p %s (%s) @ %s:%d\n", 653 lock1->li_lock, lock1->li_lock->lo_name, 654 lock1->li_lock->lo_type, lock1->li_file, 655 lock1->li_line); 656 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 657 lock->lo_name, lock->lo_type, file, line); 658 } else { 659 printf(" 1st %p %s (%s) @ %s:%d\n", 660 lock2->li_lock, lock2->li_lock->lo_name, 661 lock2->li_lock->lo_type, lock2->li_file, 662 lock2->li_line); 663 printf(" 2nd %p %s (%s) @ %s:%d\n", 664 lock1->li_lock, lock1->li_lock->lo_name, 665 lock1->li_lock->lo_type, lock1->li_file, 666 lock1->li_line); 667 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 668 lock->lo_name, lock->lo_type, file, line); 669 } 670#ifdef DDB 671 go_into_ddb = 1; 672#endif /* DDB */ 673 goto out; 674 } 675 } 676 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 677 /* 678 * Don't build a new relationship if we are locking Giant just 679 * after waking up and the previous lock in the list was acquired 680 * prior to blocking. 681 */ 682 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 683 mtx_unlock_spin(&w_mtx); 684 else { 685 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 686 lock->lo_type, lock1->li_lock->lo_type); 687 if (!itismychild(lock1->li_lock->lo_witness, w)) 688 mtx_unlock_spin(&w_mtx); 689 } 690 691out: 692#ifdef DDB 693 if (witness_ddb && go_into_ddb) 694 Debugger(__func__); 695#endif /* DDB */ 696 w->w_file = file; 697 w->w_line = line; 698 699 lle = *lock_list; 700 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 701 lle = witness_lock_list_get(); 702 if (lle == NULL) 703 return; 704 lle->ll_next = *lock_list; 705 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 706 td->td_proc->p_pid, lle); 707 *lock_list = lle; 708 } 709 lock1 = &lle->ll_children[lle->ll_count++]; 710 lock1->li_lock = lock; 711 lock1->li_line = line; 712 lock1->li_file = file; 713 if ((flags & LOP_EXCLUSIVE) != 0) 714 lock1->li_flags = LI_EXCLUSIVE; 715 else 716 lock1->li_flags = 0; 717 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 718 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 719} 720 721void 722witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 723{ 724 struct lock_instance *instance; 725 struct lock_class *class; 726 727 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 728 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 729 return; 730 class = lock->lo_class; 731 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 732 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 733 class->lc_name, lock->lo_name, file, line); 734 if ((flags & LOP_TRYLOCK) == 0) 735 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 736 lock->lo_name, file, line); 737 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 738 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 739 class->lc_name, lock->lo_name, file, line); 740 instance = find_instance(curthread->td_sleeplocks, lock); 741 if (instance == NULL) 742 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 743 class->lc_name, lock->lo_name, file, line); 744 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 745 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 746 class->lc_name, lock->lo_name, file, line); 747 if ((instance->li_flags & LI_RECURSEMASK) != 0) 748 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 749 class->lc_name, lock->lo_name, 750 instance->li_flags & LI_RECURSEMASK, file, line); 751 instance->li_flags |= LI_EXCLUSIVE; 752} 753 754void 755witness_downgrade(struct lock_object *lock, int flags, const char *file, 756 int line) 757{ 758 struct lock_instance *instance; 759 struct lock_class *class; 760 761 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 762 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 763 return; 764 class = lock->lo_class; 765 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 766 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 767 class->lc_name, lock->lo_name, file, line); 768 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 769 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 770 class->lc_name, lock->lo_name, file, line); 771 instance = find_instance(curthread->td_sleeplocks, lock); 772 if (instance == NULL) 773 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 774 class->lc_name, lock->lo_name, file, line); 775 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 776 panic("downgrade of shared lock (%s) %s @ %s:%d", 777 class->lc_name, lock->lo_name, file, line); 778 if ((instance->li_flags & LI_RECURSEMASK) != 0) 779 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 780 class->lc_name, lock->lo_name, 781 instance->li_flags & LI_RECURSEMASK, file, line); 782 instance->li_flags &= ~LI_EXCLUSIVE; 783} 784 785void 786witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 787{ 788 struct lock_list_entry **lock_list, *lle; 789 struct lock_instance *instance; 790 struct lock_class *class; 791 struct thread *td; 792 register_t s; 793 int i, j; 794 795 if (witness_cold || witness_dead || lock->lo_witness == NULL || 796 panicstr != NULL) 797 return; 798 td = curthread; 799 class = lock->lo_class; 800 if (class->lc_flags & LC_SLEEPLOCK) 801 lock_list = &td->td_sleeplocks; 802 else 803 lock_list = PCPU_PTR(spinlocks); 804 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 805 for (i = 0; i < (*lock_list)->ll_count; i++) { 806 instance = &(*lock_list)->ll_children[i]; 807 if (instance->li_lock == lock) { 808 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 809 (flags & LOP_EXCLUSIVE) == 0) { 810 printf( 811 "shared unlock of (%s) %s @ %s:%d\n", 812 class->lc_name, lock->lo_name, 813 file, line); 814 printf( 815 "while exclusively locked from %s:%d\n", 816 instance->li_file, 817 instance->li_line); 818 panic("excl->ushare"); 819 } 820 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 821 (flags & LOP_EXCLUSIVE) != 0) { 822 printf( 823 "exclusive unlock of (%s) %s @ %s:%d\n", 824 class->lc_name, lock->lo_name, 825 file, line); 826 printf( 827 "while share locked from %s:%d\n", 828 instance->li_file, 829 instance->li_line); 830 panic("share->uexcl"); 831 } 832 /* If we are recursed, unrecurse. */ 833 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 834 CTR4(KTR_WITNESS, 835 "%s: pid %d unrecursed on %s r=%d", __func__, 836 td->td_proc->p_pid, 837 instance->li_lock->lo_name, 838 instance->li_flags); 839 instance->li_flags--; 840 return; 841 } 842 s = intr_disable(); 843 CTR4(KTR_WITNESS, 844 "%s: pid %d removed %s from lle[%d]", __func__, 845 td->td_proc->p_pid, 846 instance->li_lock->lo_name, 847 (*lock_list)->ll_count - 1); 848 (*lock_list)->ll_count--; 849 for (j = i; j < (*lock_list)->ll_count; j++) 850 (*lock_list)->ll_children[j] = 851 (*lock_list)->ll_children[j + 1]; 852 intr_restore(s); 853 if ((*lock_list)->ll_count == 0) { 854 lle = *lock_list; 855 *lock_list = lle->ll_next; 856 CTR3(KTR_WITNESS, 857 "%s: pid %d removed lle %p", __func__, 858 td->td_proc->p_pid, lle); 859 witness_lock_list_free(lle); 860 } 861 return; 862 } 863 } 864 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 865 file, line); 866} 867 868/* 869 * Warn if any held locks are not sleepable. Note that Giant and the lock 870 * passed in are both special cases since they are both released during the 871 * sleep process and aren't actually held while the thread is asleep. 872 */ 873int 874witness_sleep(int check_only, struct lock_object *lock, const char *file, 875 int line) 876{ 877 struct lock_list_entry **lock_list, *lle; 878 struct lock_instance *lock1; 879 struct thread *td; 880 int i, n; 881 882 if (witness_dead || panicstr != NULL) 883 return (0); 884 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 885 n = 0; 886 /* 887 * Preemption bad because we need PCPU_PTR(spinlocks) to not change. 888 */ 889 critical_enter(); 890 td = curthread; 891 lock_list = &td->td_sleeplocks; 892again: 893 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 894 for (i = lle->ll_count - 1; i >= 0; i--) { 895 lock1 = &lle->ll_children[i]; 896 if (lock1->li_lock == lock || 897 lock1->li_lock == &Giant.mtx_object) 898 continue; 899 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 900 if (check_only == 0) { 901 CTR3(KTR_WITNESS, 902 "pid %d: sleeping with lock (%s) %s held", 903 td->td_proc->p_pid, 904 lock1->li_lock->lo_class->lc_name, 905 lock1->li_lock->lo_name); 906 lock1->li_flags |= LI_SLEPT; 907 } 908 continue; 909 } 910 n++; 911 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 912 file, line, check_only ? "could sleep" : "sleeping", 913 lock1->li_lock->lo_name, lock1->li_file, 914 lock1->li_line); 915 } 916 if (lock_list == &td->td_sleeplocks) { 917 lock_list = PCPU_PTR(spinlocks); 918 goto again; 919 } 920#ifdef DDB 921 if (witness_ddb && n) 922 Debugger(__func__); 923#endif /* DDB */ 924 critical_exit(); 925 return (n); 926} 927 928static struct witness * 929enroll(const char *description, struct lock_class *lock_class) 930{ 931 struct witness *w; 932 933 if (!witness_watch || witness_dead || panicstr != NULL) 934 return (NULL); 935 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 936 return (NULL); 937 mtx_lock_spin(&w_mtx); 938 STAILQ_FOREACH(w, &w_all, w_list) { 939 if (strcmp(description, w->w_name) == 0) { 940 w->w_refcount++; 941 mtx_unlock_spin(&w_mtx); 942 if (lock_class != w->w_class) 943 panic( 944 "lock (%s) %s does not match earlier (%s) lock", 945 description, lock_class->lc_name, 946 w->w_class->lc_name); 947 return (w); 948 } 949 } 950 /* 951 * This isn't quite right, as witness_cold is still 0 while we 952 * enroll all the locks initialized before witness_initialize(). 953 */ 954 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 955 mtx_unlock_spin(&w_mtx); 956 panic("spin lock %s not in order list", description); 957 } 958 if ((w = witness_get()) == NULL) 959 return (NULL); 960 w->w_name = description; 961 w->w_class = lock_class; 962 w->w_refcount = 1; 963 STAILQ_INSERT_HEAD(&w_all, w, w_list); 964 if (lock_class->lc_flags & LC_SPINLOCK) 965 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 966 else if (lock_class->lc_flags & LC_SLEEPLOCK) 967 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 968 else { 969 mtx_unlock_spin(&w_mtx); 970 panic("lock class %s is not sleep or spin", 971 lock_class->lc_name); 972 } 973 mtx_unlock_spin(&w_mtx); 974 return (w); 975} 976 977static int 978itismychild(struct witness *parent, struct witness *child) 979{ 980 static int recursed; 981 struct witness_child_list_entry **wcl; 982 struct witness_list *list; 983 984 MPASS(child != NULL && parent != NULL); 985 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 986 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 987 panic( 988 "%s: parent (%s) and child (%s) are not the same lock type", 989 __func__, parent->w_class->lc_name, 990 child->w_class->lc_name); 991 992 /* 993 * Insert "child" after "parent" 994 */ 995 wcl = &parent->w_children; 996 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 997 wcl = &(*wcl)->wcl_next; 998 if (*wcl == NULL) { 999 *wcl = witness_child_get(); 1000 if (*wcl == NULL) 1001 return (1); 1002 } 1003 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1004 1005 /* 1006 * Now prune whole tree. We look for cases where a lock is now 1007 * both a descendant and a direct child of a given lock. In that 1008 * case, we want to remove the direct child link from the tree. 1009 */ 1010 if (recursed) 1011 return (0); 1012 recursed = 1; 1013 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1014 list = &w_sleep; 1015 else 1016 list = &w_spin; 1017 STAILQ_FOREACH(child, list, w_typelist) { 1018 STAILQ_FOREACH(parent, list, w_typelist) { 1019 if (!isitmychild(parent, child)) 1020 continue; 1021 removechild(parent, child); 1022 if (isitmydescendant(parent, child)) 1023 continue; 1024 itismychild(parent, child); 1025 } 1026 } 1027 recursed = 0; 1028 witness_levelall(); 1029 return (0); 1030} 1031 1032static void 1033removechild(struct witness *parent, struct witness *child) 1034{ 1035 struct witness_child_list_entry **wcl, *wcl1; 1036 int i; 1037 1038 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1039 for (i = 0; i < (*wcl)->wcl_count; i++) 1040 if ((*wcl)->wcl_children[i] == child) 1041 goto found; 1042 return; 1043found: 1044 (*wcl)->wcl_count--; 1045 if ((*wcl)->wcl_count > i) 1046 (*wcl)->wcl_children[i] = 1047 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1048 MPASS((*wcl)->wcl_children[i] != NULL); 1049 if ((*wcl)->wcl_count != 0) 1050 return; 1051 wcl1 = *wcl; 1052 *wcl = wcl1->wcl_next; 1053 witness_child_free(wcl1); 1054} 1055 1056static int 1057isitmychild(struct witness *parent, struct witness *child) 1058{ 1059 struct witness_child_list_entry *wcl; 1060 int i; 1061 1062 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1063 for (i = 0; i < wcl->wcl_count; i++) { 1064 if (wcl->wcl_children[i] == child) 1065 return (1); 1066 } 1067 } 1068 return (0); 1069} 1070 1071static int 1072isitmydescendant(struct witness *parent, struct witness *child) 1073{ 1074 struct witness_child_list_entry *wcl; 1075 int i, j; 1076 1077 if (isitmychild(parent, child)) 1078 return (1); 1079 j = 0; 1080 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1081 MPASS(j < 1000); 1082 for (i = 0; i < wcl->wcl_count; i++) { 1083 if (isitmydescendant(wcl->wcl_children[i], child)) 1084 return (1); 1085 } 1086 j++; 1087 } 1088 return (0); 1089} 1090 1091void 1092witness_levelall (void) 1093{ 1094 struct witness_list *list; 1095 struct witness *w, *w1; 1096 1097 /* 1098 * First clear all levels. 1099 */ 1100 STAILQ_FOREACH(w, &w_all, w_list) { 1101 w->w_level = 0; 1102 } 1103 1104 /* 1105 * Look for locks with no parent and level all their descendants. 1106 */ 1107 STAILQ_FOREACH(w, &w_all, w_list) { 1108 /* 1109 * This is just an optimization, technically we could get 1110 * away just walking the all list each time. 1111 */ 1112 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1113 list = &w_sleep; 1114 else 1115 list = &w_spin; 1116 STAILQ_FOREACH(w1, list, w_typelist) { 1117 if (isitmychild(w1, w)) 1118 goto skip; 1119 } 1120 witness_leveldescendents(w, 0); 1121 skip: 1122 } 1123} 1124 1125static void 1126witness_leveldescendents(struct witness *parent, int level) 1127{ 1128 struct witness_child_list_entry *wcl; 1129 int i; 1130 1131 if (parent->w_level < level) 1132 parent->w_level = level; 1133 level++; 1134 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1135 for (i = 0; i < wcl->wcl_count; i++) 1136 witness_leveldescendents(wcl->wcl_children[i], level); 1137} 1138 1139static void 1140witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1141 struct witness *parent) 1142{ 1143 struct witness_child_list_entry *wcl; 1144 int i, level; 1145 1146 level = parent->w_level; 1147 prnt("%-2d", level); 1148 for (i = 0; i < level; i++) 1149 prnt(" "); 1150 prnt("%s", parent->w_name); 1151 if (parent->w_file != NULL) 1152 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1153 parent->w_line); 1154 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1155 for (i = 0; i < wcl->wcl_count; i++) 1156 witness_displaydescendants(prnt, 1157 wcl->wcl_children[i]); 1158} 1159 1160static int 1161blessed(struct witness *w1, struct witness *w2) 1162{ 1163 int i; 1164 struct witness_blessed *b; 1165 1166 for (i = 0; i < blessed_count; i++) { 1167 b = &blessed_list[i]; 1168 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1169 if (strcmp(w2->w_name, b->b_lock2) == 0) 1170 return (1); 1171 continue; 1172 } 1173 if (strcmp(w1->w_name, b->b_lock2) == 0) 1174 if (strcmp(w2->w_name, b->b_lock1) == 0) 1175 return (1); 1176 } 1177 return (0); 1178} 1179 1180static struct witness * 1181witness_get(void) 1182{ 1183 struct witness *w; 1184 1185 if (witness_dead) { 1186 mtx_unlock_spin(&w_mtx); 1187 return (NULL); 1188 } 1189 if (STAILQ_EMPTY(&w_free)) { 1190 witness_dead = 1; 1191 mtx_unlock_spin(&w_mtx); 1192 printf("%s: witness exhausted\n", __func__); 1193 return (NULL); 1194 } 1195 w = STAILQ_FIRST(&w_free); 1196 STAILQ_REMOVE_HEAD(&w_free, w_list); 1197 bzero(w, sizeof(*w)); 1198 return (w); 1199} 1200 1201static void 1202witness_free(struct witness *w) 1203{ 1204 1205 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1206} 1207 1208static struct witness_child_list_entry * 1209witness_child_get(void) 1210{ 1211 struct witness_child_list_entry *wcl; 1212 1213 if (witness_dead) { 1214 mtx_unlock_spin(&w_mtx); 1215 return (NULL); 1216 } 1217 wcl = w_child_free; 1218 if (wcl == NULL) { 1219 witness_dead = 1; 1220 mtx_unlock_spin(&w_mtx); 1221 printf("%s: witness exhausted\n", __func__); 1222 return (NULL); 1223 } 1224 w_child_free = wcl->wcl_next; 1225 bzero(wcl, sizeof(*wcl)); 1226 return (wcl); 1227} 1228 1229static void 1230witness_child_free(struct witness_child_list_entry *wcl) 1231{ 1232 1233 wcl->wcl_next = w_child_free; 1234 w_child_free = wcl; 1235} 1236 1237static struct lock_list_entry * 1238witness_lock_list_get(void) 1239{ 1240 struct lock_list_entry *lle; 1241 1242 if (witness_dead) 1243 return (NULL); 1244 mtx_lock_spin(&w_mtx); 1245 lle = w_lock_list_free; 1246 if (lle == NULL) { 1247 witness_dead = 1; 1248 mtx_unlock_spin(&w_mtx); 1249 printf("%s: witness exhausted\n", __func__); 1250 return (NULL); 1251 } 1252 w_lock_list_free = lle->ll_next; 1253 mtx_unlock_spin(&w_mtx); 1254 bzero(lle, sizeof(*lle)); 1255 return (lle); 1256} 1257 1258static void 1259witness_lock_list_free(struct lock_list_entry *lle) 1260{ 1261 1262 mtx_lock_spin(&w_mtx); 1263 lle->ll_next = w_lock_list_free; 1264 w_lock_list_free = lle; 1265 mtx_unlock_spin(&w_mtx); 1266} 1267 1268static struct lock_instance * 1269find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1270{ 1271 struct lock_list_entry *lle; 1272 struct lock_instance *instance; 1273 int i; 1274 1275 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1276 for (i = lle->ll_count - 1; i >= 0; i--) { 1277 instance = &lle->ll_children[i]; 1278 if (instance->li_lock == lock) 1279 return (instance); 1280 } 1281 return (NULL); 1282} 1283 1284int 1285witness_list_locks(struct lock_list_entry **lock_list) 1286{ 1287 struct lock_list_entry *lle; 1288 struct lock_instance *instance; 1289 struct lock_object *lock; 1290 int i, nheld; 1291 1292 nheld = 0; 1293 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1294 for (i = lle->ll_count - 1; i >= 0; i--) { 1295 instance = &lle->ll_children[i]; 1296 lock = instance->li_lock; 1297 printf("%s %s %s", 1298 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1299 "exclusive" : "shared", 1300 lock->lo_class->lc_name, lock->lo_name); 1301 if (lock->lo_type != lock->lo_name) 1302 printf(" (%s)", lock->lo_type); 1303 printf(" r = %d (%p) locked @ %s:%d\n", 1304 instance->li_flags & LI_RECURSEMASK, lock, 1305 instance->li_file, instance->li_line); 1306 nheld++; 1307 } 1308 return (nheld); 1309} 1310 1311/* 1312 * Calling this on td != curthread is bad unless we are in ddb. 1313 */ 1314int 1315witness_list(struct thread *td) 1316{ 1317 int nheld; 1318 1319 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1320#ifdef DDB 1321 KASSERT(td == curthread || db_active, 1322 ("%s: td != curthread and we aren't in the debugger", __func__)); 1323 if (!db_active && witness_dead) 1324 return (0); 1325#else 1326 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1327 if (witness_dead) 1328 return (0); 1329#endif 1330 nheld = witness_list_locks(&td->td_sleeplocks); 1331 1332 /* 1333 * We only handle spinlocks if td == curthread. This is somewhat broken 1334 * if td is currently executing on some other CPU and holds spin locks 1335 * as we won't display those locks. If we had a MI way of getting 1336 * the per-cpu data for a given cpu then we could use 1337 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1338 * and "fix" this. 1339 * 1340 * That still wouldn't really fix this unless we locked sched_lock 1341 * or stopped the other CPU to make sure it wasn't changing the list 1342 * out from under us. It is probably best to just not try to handle 1343 * threads on other CPU's for now. 1344 */ 1345 if (td == curthread) { 1346 /* 1347 * Preemption bad because we need PCPU_PTR(spinlocks) to not 1348 * change. 1349 */ 1350 critical_enter(); 1351 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1352 critical_exit(); 1353 } 1354 return (nheld); 1355} 1356 1357void 1358witness_save(struct lock_object *lock, const char **filep, int *linep) 1359{ 1360 struct lock_instance *instance; 1361 1362 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1363 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1364 return; 1365 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1366 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1367 lock->lo_class->lc_name, lock->lo_name); 1368 instance = find_instance(curthread->td_sleeplocks, lock); 1369 if (instance == NULL) 1370 panic("%s: lock (%s) %s not locked", __func__, 1371 lock->lo_class->lc_name, lock->lo_name); 1372 *filep = instance->li_file; 1373 *linep = instance->li_line; 1374} 1375 1376void 1377witness_restore(struct lock_object *lock, const char *file, int line) 1378{ 1379 struct lock_instance *instance; 1380 1381 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1382 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1383 return; 1384 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1385 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1386 lock->lo_class->lc_name, lock->lo_name); 1387 instance = find_instance(curthread->td_sleeplocks, lock); 1388 if (instance == NULL) 1389 panic("%s: lock (%s) %s not locked", __func__, 1390 lock->lo_class->lc_name, lock->lo_name); 1391 lock->lo_witness->w_file = file; 1392 lock->lo_witness->w_line = line; 1393 instance->li_file = file; 1394 instance->li_line = line; 1395} 1396 1397void 1398witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1399{ 1400#ifdef INVARIANT_SUPPORT 1401 struct lock_instance *instance; 1402 1403 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1404 return; 1405 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1406 instance = find_instance(curthread->td_sleeplocks, lock); 1407 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1408 instance = find_instance(PCPU_GET(spinlocks), lock); 1409 else { 1410 panic("Lock (%s) %s is not sleep or spin!", 1411 lock->lo_class->lc_name, lock->lo_name); 1412 return; 1413 } 1414 switch (flags) { 1415 case LA_UNLOCKED: 1416 if (instance != NULL) 1417 panic("Lock (%s) %s locked @ %s:%d.", 1418 lock->lo_class->lc_name, lock->lo_name, file, line); 1419 break; 1420 case LA_LOCKED: 1421 case LA_LOCKED | LA_RECURSED: 1422 case LA_LOCKED | LA_NOTRECURSED: 1423 case LA_SLOCKED: 1424 case LA_SLOCKED | LA_RECURSED: 1425 case LA_SLOCKED | LA_NOTRECURSED: 1426 case LA_XLOCKED: 1427 case LA_XLOCKED | LA_RECURSED: 1428 case LA_XLOCKED | LA_NOTRECURSED: 1429 if (instance == NULL) { 1430 panic("Lock (%s) %s not locked @ %s:%d.", 1431 lock->lo_class->lc_name, lock->lo_name, file, line); 1432 break; 1433 } 1434 if ((flags & LA_XLOCKED) != 0 && 1435 (instance->li_flags & LI_EXCLUSIVE) == 0) 1436 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1437 lock->lo_class->lc_name, lock->lo_name, file, line); 1438 if ((flags & LA_SLOCKED) != 0 && 1439 (instance->li_flags & LI_EXCLUSIVE) != 0) 1440 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1441 lock->lo_class->lc_name, lock->lo_name, file, line); 1442 if ((flags & LA_RECURSED) != 0 && 1443 (instance->li_flags & LI_RECURSEMASK) == 0) 1444 panic("Lock (%s) %s not recursed @ %s:%d.", 1445 lock->lo_class->lc_name, lock->lo_name, file, line); 1446 if ((flags & LA_NOTRECURSED) != 0 && 1447 (instance->li_flags & LI_RECURSEMASK) != 0) 1448 panic("Lock (%s) %s recursed @ %s:%d.", 1449 lock->lo_class->lc_name, lock->lo_name, file, line); 1450 break; 1451 default: 1452 panic("Invalid lock assertion at %s:%d.", file, line); 1453 1454 } 1455#endif /* INVARIANT_SUPPORT */ 1456} 1457 1458#ifdef DDB 1459 1460DB_SHOW_COMMAND(locks, db_witness_list) 1461{ 1462 struct thread *td; 1463 pid_t pid; 1464 struct proc *p; 1465 1466 if (have_addr) { 1467 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1468 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1469 ((addr >> 16) % 16) * 10000; 1470 /* sx_slock(&allproc_lock); */ 1471 FOREACH_PROC_IN_SYSTEM(p) { 1472 if (p->p_pid == pid) 1473 break; 1474 } 1475 /* sx_sunlock(&allproc_lock); */ 1476 if (p == NULL) { 1477 db_printf("pid %d not found\n", pid); 1478 return; 1479 } 1480 FOREACH_THREAD_IN_PROC(p, td) { 1481 witness_list(td); 1482 } 1483 } else { 1484 td = curthread; 1485 witness_list(td); 1486 } 1487} 1488 1489DB_SHOW_COMMAND(witness, db_witness_display) 1490{ 1491 1492 witness_display(db_printf); 1493} 1494#endif 1495