subr_witness.c revision 83798
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 83798 2001-09-21 21:54:45Z 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 { "proctree", &lock_class_sx }, 192 { "allproc", &lock_class_sx }, 193 { "process lock", &lock_class_mtx_sleep }, 194 { "uidinfo hash", &lock_class_mtx_sleep }, 195 { "uidinfo struct", &lock_class_mtx_sleep }, 196 { NULL, NULL }, 197 /* 198 * spin locks 199 */ 200#if defined(__i386__) && defined (SMP) 201 { "com", &lock_class_mtx_spin }, 202#endif 203 { "sio", &lock_class_mtx_spin }, 204#ifdef __i386__ 205 { "cy", &lock_class_mtx_spin }, 206#endif 207 { "ng_node", &lock_class_mtx_spin }, 208 { "ng_worklist", &lock_class_mtx_spin }, 209 { "ithread table lock", &lock_class_mtx_spin }, 210 { "sched lock", &lock_class_mtx_spin }, 211 { "callout", &lock_class_mtx_spin }, 212 /* 213 * leaf locks 214 */ 215#ifdef SMP 216 { "ap boot", &lock_class_mtx_spin }, 217#ifdef __i386__ 218 { "imen", &lock_class_mtx_spin }, 219#endif 220 { "smp rendezvous", &lock_class_mtx_spin }, 221#endif 222 { "clk", &lock_class_mtx_spin }, 223 { NULL, NULL }, 224 { NULL, NULL } 225}; 226 227static const char *dup_list[] = { 228 "process lock", 229 NULL 230}; 231 232/* 233 * Pairs of locks which have been blessed 234 * Don't complain about order problems with blessed locks 235 */ 236static struct witness_blessed blessed_list[] = { 237}; 238static int blessed_count = 239 sizeof(blessed_list) / sizeof(struct witness_blessed); 240 241/* 242 * List of all locks in the system. 243 */ 244STAILQ_HEAD(, lock_object) all_locks = STAILQ_HEAD_INITIALIZER(all_locks); 245 246static struct mtx all_mtx = { 247 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 248 "All locks list", /* mtx_object.lo_name */ 249 LO_INITIALIZED, /* mtx_object.lo_flags */ 250 { NULL }, /* mtx_object.lo_list */ 251 NULL }, /* mtx_object.lo_witness */ 252 MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */ 253 0, /* mtx_savecrit */ 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 CTR0(KTR_WITNESS, __func__ ": initializing witness"); 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 CTR1(KTR_WITNESS, 386 __func__ ": marking witness %s as dead", 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 /* 480 * We have to hold a spinlock to keep lock_list valid across the check 481 * in the LC_SLEEPLOCK case. In the LC_SPINLOCK case, it is already 482 * protected by the spinlock we are currently performing the witness 483 * checks on, so it is ok to release the lock after performing this 484 * check. All we have to protect is the LC_SLEEPLOCK case when no 485 * spinlocks are held as we may get preempted during this check and 486 * lock_list could end up pointing to some other CPU's spinlock list. 487 */ 488 mtx_lock_spin(&w_mtx); 489 lock_list = PCPU_PTR(spinlocks); 490 if (class->lc_flags & LC_SLEEPLOCK) { 491 if (*lock_list != NULL && (flags & LOP_TRYLOCK) == 0) { 492 mtx_unlock_spin(&w_mtx); 493 panic("blockable sleep lock (%s) %s @ %s:%d", 494 class->lc_name, lock->lo_name, file, line); 495 } 496 lock_list = &td->td_sleeplocks; 497 } 498 mtx_unlock_spin(&w_mtx); 499 500 /* 501 * Try locks do not block if they fail to acquire the lock, thus 502 * there is no danger of deadlocks or of switching while holding a 503 * spin lock if we acquire a lock via a try operation. 504 */ 505 if (flags & LOP_TRYLOCK) 506 goto out; 507 508 /* 509 * Is this the first lock acquired? If so, then no order checking 510 * is needed. 511 */ 512 if (*lock_list == NULL) 513 goto out; 514 515 /* 516 * Check to see if we are recursing on a lock we already own. 517 */ 518 lock1 = find_instance(*lock_list, lock); 519 if (lock1 != NULL) { 520 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 521 (flags & LOP_EXCLUSIVE) == 0) { 522 printf("shared lock of (%s) %s @ %s:%d\n", 523 class->lc_name, lock->lo_name, file, line); 524 printf("while exclusively locked from %s:%d\n", 525 lock1->li_file, lock1->li_line); 526 panic("share->excl"); 527 } 528 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 529 (flags & LOP_EXCLUSIVE) != 0) { 530 printf("exclusive lock of (%s) %s @ %s:%d\n", 531 class->lc_name, lock->lo_name, file, line); 532 printf("while share locked from %s:%d\n", 533 lock1->li_file, lock1->li_line); 534 panic("excl->share"); 535 } 536 lock1->li_flags++; 537 if ((lock->lo_flags & LO_RECURSABLE) == 0) { 538 printf( 539 "recursed on non-recursive lock (%s) %s @ %s:%d\n", 540 class->lc_name, lock->lo_name, file, line); 541 printf("first acquired @ %s:%d\n", lock1->li_file, 542 lock1->li_line); 543 panic("recurse"); 544 } 545 CTR3(KTR_WITNESS, __func__ ": pid %d recursed on %s r=%d", 546 curproc->p_pid, lock->lo_name, 547 lock1->li_flags & LI_RECURSEMASK); 548 lock1->li_file = file; 549 lock1->li_line = line; 550 return; 551 } 552 553 /* 554 * Check for duplicate locks of the same type. Note that we only 555 * have to check for this on the last lock we just acquired. Any 556 * other cases will be caught as lock order violations. 557 */ 558 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 559 w1 = lock1->li_lock->lo_witness; 560 if (w1 == w) { 561 if (w->w_same_squawked || dup_ok(w)) 562 goto out; 563 w->w_same_squawked = 1; 564 printf("acquiring duplicate lock of same type: \"%s\"\n", 565 lock->lo_name); 566 printf(" 1st @ %s:%d\n", lock1->li_file, lock1->li_line); 567 printf(" 2nd @ %s:%d\n", file, line); 568#ifdef DDB 569 go_into_ddb = 1; 570#endif /* DDB */ 571 goto out; 572 } 573 MPASS(!mtx_owned(&w_mtx)); 574 mtx_lock_spin(&w_mtx); 575 /* 576 * If we have a known higher number just say ok 577 */ 578 if (witness_watch > 1 && w->w_level > w1->w_level) { 579 mtx_unlock_spin(&w_mtx); 580 goto out; 581 } 582 if (isitmydescendant(w1, w)) { 583 mtx_unlock_spin(&w_mtx); 584 goto out; 585 } 586 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 587 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 588 589 MPASS(j < WITNESS_COUNT); 590 lock1 = &lle->ll_children[i]; 591 w1 = lock1->li_lock->lo_witness; 592 593 /* 594 * If this lock doesn't undergo witness checking, 595 * then skip it. 596 */ 597 if (w1 == NULL) { 598 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 599 ("lock missing witness structure")); 600 continue; 601 } 602 /* 603 * If we are locking Giant and we slept with this 604 * lock, then skip it. 605 */ 606 if ((lock1->li_flags & LI_SLEPT) != 0 && 607 lock == &Giant.mtx_object) 608 continue; 609 if (!isitmydescendant(w, w1)) 610 continue; 611 /* 612 * We have a lock order violation, check to see if it 613 * is allowed or has already been yelled about. 614 */ 615 mtx_unlock_spin(&w_mtx); 616 if (blessed(w, w1)) 617 goto out; 618 if (lock1->li_lock == &Giant.mtx_object) { 619 if (w1->w_Giant_squawked) 620 goto out; 621 else 622 w1->w_Giant_squawked = 1; 623 } else { 624 if (w1->w_other_squawked) 625 goto out; 626 else 627 w1->w_other_squawked = 1; 628 } 629 /* 630 * Ok, yell about it. 631 */ 632 printf("lock order reversal\n"); 633 /* 634 * Try to locate an earlier lock with 635 * witness w in our list. 636 */ 637 do { 638 lock2 = &lle->ll_children[i]; 639 MPASS(lock2->li_lock != NULL); 640 if (lock2->li_lock->lo_witness == w) 641 break; 642 i--; 643 if (i == 0 && lle->ll_next != NULL) { 644 lle = lle->ll_next; 645 i = lle->ll_count - 1; 646 MPASS(i != 0); 647 } 648 } while (i >= 0); 649 if (i < 0) { 650 printf(" 1st %p %s @ %s:%d\n", lock1->li_lock, 651 lock1->li_lock->lo_name, lock1->li_file, 652 lock1->li_line); 653 printf(" 2nd %p %s @ %s:%d\n", lock, 654 lock->lo_name, file, line); 655 } else { 656 printf(" 1st %p %s @ %s:%d\n", lock2->li_lock, 657 lock2->li_lock->lo_name, lock2->li_file, 658 lock2->li_line); 659 printf(" 2nd %p %s @ %s:%d\n", lock1->li_lock, 660 lock1->li_lock->lo_name, lock1->li_file, 661 lock1->li_line); 662 printf(" 3rd %p %s @ %s:%d\n", lock, 663 lock->lo_name, file, line); 664 } 665#ifdef DDB 666 go_into_ddb = 1; 667#endif /* DDB */ 668 goto out; 669 } 670 } 671 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 672 /* 673 * Don't build a new relationship if we are locking Giant just 674 * after waking up and the previous lock in the list was acquired 675 * prior to blocking. 676 */ 677 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 678 mtx_unlock_spin(&w_mtx); 679 else { 680 CTR2(KTR_WITNESS, __func__ ": adding %s as a child of %s", 681 lock->lo_name, lock1->li_lock->lo_name); 682 if (!itismychild(lock1->li_lock->lo_witness, w)) 683 mtx_unlock_spin(&w_mtx); 684 } 685 686out: 687#ifdef DDB 688 if (witness_ddb && go_into_ddb) 689 Debugger(__func__); 690#endif /* DDB */ 691 w->w_file = file; 692 w->w_line = line; 693 694 lle = *lock_list; 695 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 696 lle = witness_lock_list_get(); 697 if (lle == NULL) 698 return; 699 lle->ll_next = *lock_list; 700 CTR2(KTR_WITNESS, __func__ ": pid %d added lle %p", 701 curproc->p_pid, lle); 702 *lock_list = lle; 703 } 704 lock1 = &lle->ll_children[lle->ll_count++]; 705 lock1->li_lock = lock; 706 lock1->li_line = line; 707 lock1->li_file = file; 708 if ((flags & LOP_EXCLUSIVE) != 0) 709 lock1->li_flags = LI_EXCLUSIVE; 710 else 711 lock1->li_flags = 0; 712 CTR3(KTR_WITNESS, __func__ ": pid %d added %s as lle[%d]", 713 curproc->p_pid, lock->lo_name, lle->ll_count - 1); 714} 715 716void 717witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 718{ 719 struct lock_instance *instance; 720 struct lock_class *class; 721 722 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 723 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 724 return; 725 class = lock->lo_class; 726 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 727 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 728 class->lc_name, lock->lo_name, file, line); 729 if ((flags & LOP_TRYLOCK) == 0) 730 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 731 lock->lo_name, file, line); 732 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 733 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 734 class->lc_name, lock->lo_name, file, line); 735 instance = find_instance(curthread->td_sleeplocks, lock); 736 if (instance == NULL) 737 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 738 class->lc_name, lock->lo_name, file, line); 739 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 740 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 741 class->lc_name, lock->lo_name, file, line); 742 if ((instance->li_flags & LI_RECURSEMASK) != 0) 743 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 744 class->lc_name, lock->lo_name, 745 instance->li_flags & LI_RECURSEMASK, file, line); 746 instance->li_flags |= LI_EXCLUSIVE; 747} 748 749void 750witness_downgrade(struct lock_object *lock, int flags, const char *file, 751 int line) 752{ 753 struct lock_instance *instance; 754 struct lock_class *class; 755 756 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 757 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 758 return; 759 class = lock->lo_class; 760 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 761 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 762 class->lc_name, lock->lo_name, file, line); 763 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 764 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 765 class->lc_name, lock->lo_name, file, line); 766 instance = find_instance(curthread->td_sleeplocks, lock); 767 if (instance == NULL) 768 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 769 class->lc_name, lock->lo_name, file, line); 770 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 771 panic("downgrade of shared lock (%s) %s @ %s:%d", 772 class->lc_name, lock->lo_name, file, line); 773 if ((instance->li_flags & LI_RECURSEMASK) != 0) 774 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 775 class->lc_name, lock->lo_name, 776 instance->li_flags & LI_RECURSEMASK, file, line); 777 instance->li_flags &= ~LI_EXCLUSIVE; 778} 779 780void 781witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 782{ 783 struct lock_list_entry **lock_list, *lle; 784 struct lock_instance *instance; 785 struct lock_class *class; 786 struct thread *td; 787 critical_t s; 788 int i, j; 789 790 if (witness_cold || witness_dead || lock->lo_witness == NULL || 791 panicstr != NULL) 792 return; 793 td = curthread; 794 class = lock->lo_class; 795 if (class->lc_flags & LC_SLEEPLOCK) 796 lock_list = &td->td_sleeplocks; 797 else 798 lock_list = PCPU_PTR(spinlocks); 799 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 800 for (i = 0; i < (*lock_list)->ll_count; i++) { 801 instance = &(*lock_list)->ll_children[i]; 802 if (instance->li_lock == lock) { 803 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 804 (flags & LOP_EXCLUSIVE) == 0) { 805 printf( 806 "shared unlock of (%s) %s @ %s:%d\n", 807 class->lc_name, lock->lo_name, 808 file, line); 809 printf( 810 "while exclusively locked from %s:%d\n", 811 instance->li_file, 812 instance->li_line); 813 panic("excl->ushare"); 814 } 815 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 816 (flags & LOP_EXCLUSIVE) != 0) { 817 printf( 818 "exclusive unlock of (%s) %s @ %s:%d\n", 819 class->lc_name, lock->lo_name, 820 file, line); 821 printf( 822 "while share locked from %s:%d\n", 823 instance->li_file, 824 instance->li_line); 825 panic("share->uexcl"); 826 } 827 /* If we are recursed, unrecurse. */ 828 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 829 CTR3(KTR_WITNESS, 830 __func__ ": pid %d unrecursed on %s r=%d", 831 curproc->p_pid, 832 instance->li_lock->lo_name, 833 instance->li_flags); 834 instance->li_flags--; 835 goto out; 836 } 837 s = critical_enter(); 838 CTR3(KTR_WITNESS, 839 __func__ ": pid %d removed %s from lle[%d]", 840 curproc->p_pid, instance->li_lock->lo_name, 841 (*lock_list)->ll_count - 1); 842 (*lock_list)->ll_count--; 843 for (j = i; j < (*lock_list)->ll_count; j++) 844 (*lock_list)->ll_children[j] = 845 (*lock_list)->ll_children[j + 1]; 846 critical_exit(s); 847 if ((*lock_list)->ll_count == 0) { 848 lle = *lock_list; 849 *lock_list = lle->ll_next; 850 CTR2(KTR_WITNESS, 851 __func__ ": pid %d removed lle %p", 852 curproc->p_pid, lle); 853 witness_lock_list_free(lle); 854 } 855 goto out; 856 } 857 } 858 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 859 file, line); 860out: 861 /* 862 * We don't need to protect this PCPU_GET() here against preemption 863 * because if we hold any spinlocks then we are already protected, 864 * and if we don't we will get NULL if we hold no spinlocks even if 865 * we switch CPU's while reading it. 866 */ 867 if (class->lc_flags & LC_SLEEPLOCK) { 868 if ((flags & LOP_NOSWITCH) == 0 && PCPU_GET(spinlocks) != NULL) 869 panic("switchable sleep unlock (%s) %s @ %s:%d", 870 class->lc_name, lock->lo_name, file, line); 871 } 872} 873 874/* 875 * Warn if any held locks are not sleepable. Note that Giant and the lock 876 * passed in are both special cases since they are both released during the 877 * sleep process and aren't actually held while the thread is asleep. 878 */ 879int 880witness_sleep(int check_only, struct lock_object *lock, const char *file, 881 int line) 882{ 883 struct lock_list_entry **lock_list, *lle; 884 struct lock_instance *lock1; 885 struct thread *td; 886 critical_t savecrit; 887 int i, n; 888 889 if (witness_dead || panicstr != NULL) 890 return (0); 891 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 892 n = 0; 893 /* 894 * Preemption bad because we need PCPU_PTR(spinlocks) to not change. 895 */ 896 savecrit = critical_enter(); 897 td = curthread; 898 lock_list = &td->td_sleeplocks; 899again: 900 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 901 for (i = lle->ll_count - 1; i >= 0; i--) { 902 lock1 = &lle->ll_children[i]; 903 if (lock1->li_lock == lock || 904 lock1->li_lock == &Giant.mtx_object) 905 continue; 906 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 907 if (check_only == 0) { 908 CTR3(KTR_WITNESS, 909 "pid %d: sleeping with lock (%s) %s held", 910 curproc->p_pid, 911 lock1->li_lock->lo_class->lc_name, 912 lock1->li_lock->lo_name); 913 lock1->li_flags |= LI_SLEPT; 914 } 915 continue; 916 } 917 n++; 918 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 919 file, line, check_only ? "could sleep" : "sleeping", 920 lock1->li_lock->lo_name, lock1->li_file, 921 lock1->li_line); 922 } 923 if (lock_list == &td->td_sleeplocks) { 924 lock_list = PCPU_PTR(spinlocks); 925 goto again; 926 } 927#ifdef DDB 928 if (witness_ddb && n) 929 Debugger(__func__); 930#endif /* DDB */ 931 critical_exit(savecrit); 932 return (n); 933} 934 935static struct witness * 936enroll(const char *description, struct lock_class *lock_class) 937{ 938 struct witness *w; 939 940 if (!witness_watch || witness_dead || panicstr != NULL) 941 return (NULL); 942 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 943 return (NULL); 944 mtx_lock_spin(&w_mtx); 945 STAILQ_FOREACH(w, &w_all, w_list) { 946 if (strcmp(description, w->w_name) == 0) { 947 w->w_refcount++; 948 mtx_unlock_spin(&w_mtx); 949 if (lock_class != w->w_class) 950 panic( 951 "lock (%s) %s does not match earlier (%s) lock", 952 description, lock_class->lc_name, 953 w->w_class->lc_name); 954 return (w); 955 } 956 } 957 /* 958 * This isn't quite right, as witness_cold is still 0 while we 959 * enroll all the locks initialized before witness_initialize(). 960 */ 961 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 962 mtx_unlock_spin(&w_mtx); 963 panic("spin lock %s not in order list", description); 964 } 965 if ((w = witness_get()) == NULL) 966 return (NULL); 967 w->w_name = description; 968 w->w_class = lock_class; 969 w->w_refcount = 1; 970 STAILQ_INSERT_HEAD(&w_all, w, w_list); 971 if (lock_class->lc_flags & LC_SPINLOCK) 972 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 973 else if (lock_class->lc_flags & LC_SLEEPLOCK) 974 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 975 else { 976 mtx_unlock_spin(&w_mtx); 977 panic("lock class %s is not sleep or spin", 978 lock_class->lc_name); 979 } 980 mtx_unlock_spin(&w_mtx); 981 return (w); 982} 983 984static int 985itismychild(struct witness *parent, struct witness *child) 986{ 987 static int recursed; 988 struct witness_child_list_entry **wcl; 989 struct witness_list *list; 990 991 MPASS(child != NULL && parent != NULL); 992 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 993 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 994 panic( 995 "%s: parent (%s) and child (%s) are not the same lock type", 996 __func__, parent->w_class->lc_name, 997 child->w_class->lc_name); 998 999 /* 1000 * Insert "child" after "parent" 1001 */ 1002 wcl = &parent->w_children; 1003 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1004 wcl = &(*wcl)->wcl_next; 1005 if (*wcl == NULL) { 1006 *wcl = witness_child_get(); 1007 if (*wcl == NULL) 1008 return (1); 1009 } 1010 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1011 1012 /* 1013 * Now prune whole tree. We look for cases where a lock is now 1014 * both a descendant and a direct child of a given lock. In that 1015 * case, we want to remove the direct child link from the tree. 1016 */ 1017 if (recursed) 1018 return (0); 1019 recursed = 1; 1020 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1021 list = &w_sleep; 1022 else 1023 list = &w_spin; 1024 STAILQ_FOREACH(child, list, w_typelist) { 1025 STAILQ_FOREACH(parent, list, w_typelist) { 1026 if (!isitmychild(parent, child)) 1027 continue; 1028 removechild(parent, child); 1029 if (isitmydescendant(parent, child)) 1030 continue; 1031 itismychild(parent, child); 1032 } 1033 } 1034 recursed = 0; 1035 witness_levelall(); 1036 return (0); 1037} 1038 1039static void 1040removechild(struct witness *parent, struct witness *child) 1041{ 1042 struct witness_child_list_entry **wcl, *wcl1; 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 goto found; 1049 return; 1050found: 1051 (*wcl)->wcl_count--; 1052 if ((*wcl)->wcl_count > i) 1053 (*wcl)->wcl_children[i] = 1054 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1055 MPASS((*wcl)->wcl_children[i] != NULL); 1056 if ((*wcl)->wcl_count != 0) 1057 return; 1058 wcl1 = *wcl; 1059 *wcl = wcl1->wcl_next; 1060 witness_child_free(wcl1); 1061} 1062 1063static int 1064isitmychild(struct witness *parent, struct witness *child) 1065{ 1066 struct witness_child_list_entry *wcl; 1067 int i; 1068 1069 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1070 for (i = 0; i < wcl->wcl_count; i++) { 1071 if (wcl->wcl_children[i] == child) 1072 return (1); 1073 } 1074 } 1075 return (0); 1076} 1077 1078static int 1079isitmydescendant(struct witness *parent, struct witness *child) 1080{ 1081 struct witness_child_list_entry *wcl; 1082 int i, j; 1083 1084 if (isitmychild(parent, child)) 1085 return (1); 1086 j = 0; 1087 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1088 MPASS(j < 1000); 1089 for (i = 0; i < wcl->wcl_count; i++) { 1090 if (isitmydescendant(wcl->wcl_children[i], child)) 1091 return (1); 1092 } 1093 j++; 1094 } 1095 return (0); 1096} 1097 1098void 1099witness_levelall (void) 1100{ 1101 struct witness_list *list; 1102 struct witness *w, *w1; 1103 1104 /* 1105 * First clear all levels. 1106 */ 1107 STAILQ_FOREACH(w, &w_all, w_list) { 1108 w->w_level = 0; 1109 } 1110 1111 /* 1112 * Look for locks with no parent and level all their descendants. 1113 */ 1114 STAILQ_FOREACH(w, &w_all, w_list) { 1115 /* 1116 * This is just an optimization, technically we could get 1117 * away just walking the all list each time. 1118 */ 1119 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1120 list = &w_sleep; 1121 else 1122 list = &w_spin; 1123 STAILQ_FOREACH(w1, list, w_typelist) { 1124 if (isitmychild(w1, w)) 1125 goto skip; 1126 } 1127 witness_leveldescendents(w, 0); 1128 skip: 1129 } 1130} 1131 1132static void 1133witness_leveldescendents(struct witness *parent, int level) 1134{ 1135 struct witness_child_list_entry *wcl; 1136 int i; 1137 1138 if (parent->w_level < level) 1139 parent->w_level = level; 1140 level++; 1141 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1142 for (i = 0; i < wcl->wcl_count; i++) 1143 witness_leveldescendents(wcl->wcl_children[i], level); 1144} 1145 1146static void 1147witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1148 struct witness *parent) 1149{ 1150 struct witness_child_list_entry *wcl; 1151 int i, level; 1152 1153 level = parent->w_level; 1154 prnt("%-2d", level); 1155 for (i = 0; i < level; i++) 1156 prnt(" "); 1157 prnt("%s", parent->w_name); 1158 if (parent->w_file != NULL) 1159 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1160 parent->w_line); 1161 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1162 for (i = 0; i < wcl->wcl_count; i++) 1163 witness_displaydescendants(prnt, 1164 wcl->wcl_children[i]); 1165} 1166 1167static int 1168dup_ok(struct witness *w) 1169{ 1170 const char **dup; 1171 1172 for (dup = dup_list; *dup != NULL; dup++) 1173 if (strcmp(w->w_name, *dup) == 0) 1174 return (1); 1175 return (0); 1176} 1177 1178static int 1179blessed(struct witness *w1, struct witness *w2) 1180{ 1181 int i; 1182 struct witness_blessed *b; 1183 1184 for (i = 0; i < blessed_count; i++) { 1185 b = &blessed_list[i]; 1186 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1187 if (strcmp(w2->w_name, b->b_lock2) == 0) 1188 return (1); 1189 continue; 1190 } 1191 if (strcmp(w1->w_name, b->b_lock2) == 0) 1192 if (strcmp(w2->w_name, b->b_lock1) == 0) 1193 return (1); 1194 } 1195 return (0); 1196} 1197 1198static struct witness * 1199witness_get(void) 1200{ 1201 struct witness *w; 1202 1203 if (witness_dead) { 1204 mtx_unlock_spin(&w_mtx); 1205 return (NULL); 1206 } 1207 if (STAILQ_EMPTY(&w_free)) { 1208 witness_dead = 1; 1209 mtx_unlock_spin(&w_mtx); 1210 printf("%s: witness exhausted\n", __func__); 1211 return (NULL); 1212 } 1213 w = STAILQ_FIRST(&w_free); 1214 STAILQ_REMOVE_HEAD(&w_free, w_list); 1215 bzero(w, sizeof(*w)); 1216 return (w); 1217} 1218 1219static void 1220witness_free(struct witness *w) 1221{ 1222 1223 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1224} 1225 1226static struct witness_child_list_entry * 1227witness_child_get(void) 1228{ 1229 struct witness_child_list_entry *wcl; 1230 1231 if (witness_dead) { 1232 mtx_unlock_spin(&w_mtx); 1233 return (NULL); 1234 } 1235 wcl = w_child_free; 1236 if (wcl == NULL) { 1237 witness_dead = 1; 1238 mtx_unlock_spin(&w_mtx); 1239 printf("%s: witness exhausted\n", __func__); 1240 return (NULL); 1241 } 1242 w_child_free = wcl->wcl_next; 1243 bzero(wcl, sizeof(*wcl)); 1244 return (wcl); 1245} 1246 1247static void 1248witness_child_free(struct witness_child_list_entry *wcl) 1249{ 1250 1251 wcl->wcl_next = w_child_free; 1252 w_child_free = wcl; 1253} 1254 1255static struct lock_list_entry * 1256witness_lock_list_get(void) 1257{ 1258 struct lock_list_entry *lle; 1259 1260 if (witness_dead) 1261 return (NULL); 1262 mtx_lock_spin(&w_mtx); 1263 lle = w_lock_list_free; 1264 if (lle == NULL) { 1265 witness_dead = 1; 1266 mtx_unlock_spin(&w_mtx); 1267 printf("%s: witness exhausted\n", __func__); 1268 return (NULL); 1269 } 1270 w_lock_list_free = lle->ll_next; 1271 mtx_unlock_spin(&w_mtx); 1272 bzero(lle, sizeof(*lle)); 1273 return (lle); 1274} 1275 1276static void 1277witness_lock_list_free(struct lock_list_entry *lle) 1278{ 1279 1280 mtx_lock_spin(&w_mtx); 1281 lle->ll_next = w_lock_list_free; 1282 w_lock_list_free = lle; 1283 mtx_unlock_spin(&w_mtx); 1284} 1285 1286static struct lock_instance * 1287find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1288{ 1289 struct lock_list_entry *lle; 1290 struct lock_instance *instance; 1291 int i; 1292 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 if (instance->li_lock == lock) 1297 return (instance); 1298 } 1299 return (NULL); 1300} 1301 1302int 1303witness_list_locks(struct lock_list_entry **lock_list) 1304{ 1305 struct lock_list_entry *lle; 1306 struct lock_instance *instance; 1307 struct lock_object *lock; 1308 int i, nheld; 1309 1310 nheld = 0; 1311 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1312 for (i = lle->ll_count - 1; i >= 0; i--) { 1313 instance = &lle->ll_children[i]; 1314 lock = instance->li_lock; 1315 printf("%s (%s) %s (%p) locked @ %s:%d\n", 1316 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1317 "exclusive" : "shared", 1318 lock->lo_class->lc_name, lock->lo_name, lock, 1319 instance->li_file, instance->li_line); 1320 nheld++; 1321 } 1322 return (nheld); 1323} 1324 1325/* 1326 * Calling this on td != curthread is bad unless we are in ddb. 1327 */ 1328int 1329witness_list(struct thread *td) 1330{ 1331 critical_t savecrit; 1332 int nheld; 1333 1334 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1335#ifdef DDB 1336 KASSERT(td == curthread || db_active, 1337 ("%s: td != curthread and we aren't in the debugger", __func__)); 1338 if (!db_active && witness_dead) 1339 return (0); 1340#else 1341 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1342 if (witness_dead) 1343 return (0); 1344#endif 1345 nheld = witness_list_locks(&td->td_sleeplocks); 1346 1347 /* 1348 * We only handle spinlocks if td == curthread. This is somewhat broken 1349 * if td is currently executing on some other CPU and holds spin locks 1350 * as we won't display those locks. If we had a MI way of getting 1351 * the per-cpu data for a given cpu then we could use 1352 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1353 * and "fix" this. 1354 */ 1355 if (td == curthread) { 1356 /* 1357 * Preemption bad because we need PCPU_PTR(spinlocks) to not 1358 * change. 1359 */ 1360 savecrit = critical_enter(); 1361 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1362 critical_exit(savecrit); 1363 } 1364 return (nheld); 1365} 1366 1367void 1368witness_save(struct lock_object *lock, const char **filep, int *linep) 1369{ 1370 struct lock_instance *instance; 1371 1372 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1373 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1374 return; 1375 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1376 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1377 lock->lo_class->lc_name, lock->lo_name); 1378 instance = find_instance(curthread->td_sleeplocks, lock); 1379 if (instance == NULL) 1380 panic("%s: lock (%s) %s not locked", __func__, 1381 lock->lo_class->lc_name, lock->lo_name); 1382 *filep = instance->li_file; 1383 *linep = instance->li_line; 1384} 1385 1386void 1387witness_restore(struct lock_object *lock, const char *file, int line) 1388{ 1389 struct lock_instance *instance; 1390 1391 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1392 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1393 return; 1394 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1395 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1396 lock->lo_class->lc_name, lock->lo_name); 1397 instance = find_instance(curthread->td_sleeplocks, lock); 1398 if (instance == NULL) 1399 panic("%s: lock (%s) %s not locked", __func__, 1400 lock->lo_class->lc_name, lock->lo_name); 1401 lock->lo_witness->w_file = file; 1402 lock->lo_witness->w_line = line; 1403 instance->li_file = file; 1404 instance->li_line = line; 1405} 1406 1407void 1408witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1409{ 1410#ifdef INVARIANT_SUPPORT 1411 struct lock_instance *instance; 1412 1413 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1414 return; 1415 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1416 instance = find_instance(curthread->td_sleeplocks, lock); 1417 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1418 instance = find_instance(PCPU_GET(spinlocks), lock); 1419 else 1420 panic("Lock (%s) %s is not sleep or spin!", 1421 lock->lo_class->lc_name, lock->lo_name); 1422 switch (flags) { 1423 case LA_UNLOCKED: 1424 if (instance != NULL) 1425 panic("Lock (%s) %s locked @ %s:%d.", 1426 lock->lo_class->lc_name, lock->lo_name, file, line); 1427 break; 1428 case LA_LOCKED: 1429 case LA_LOCKED | LA_RECURSED: 1430 case LA_LOCKED | LA_NOTRECURSED: 1431 case LA_SLOCKED: 1432 case LA_SLOCKED | LA_RECURSED: 1433 case LA_SLOCKED | LA_NOTRECURSED: 1434 case LA_XLOCKED: 1435 case LA_XLOCKED | LA_RECURSED: 1436 case LA_XLOCKED | LA_NOTRECURSED: 1437 if (instance == NULL) 1438 panic("Lock (%s) %s not locked @ %s:%d.", 1439 lock->lo_class->lc_name, lock->lo_name, file, line); 1440 if ((flags & LA_XLOCKED) != 0 && 1441 (instance->li_flags & LI_EXCLUSIVE) == 0) 1442 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1443 lock->lo_class->lc_name, lock->lo_name, file, line); 1444 if ((flags & LA_SLOCKED) != 0 && 1445 (instance->li_flags & LI_EXCLUSIVE) != 0) 1446 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1447 lock->lo_class->lc_name, lock->lo_name, file, line); 1448 if ((flags & LA_RECURSED) != 0 && 1449 (instance->li_flags & LI_RECURSEMASK) == 0) 1450 panic("Lock (%s) %s not recursed @ %s:%d.", 1451 lock->lo_class->lc_name, lock->lo_name, file, line); 1452 if ((flags & LA_NOTRECURSED) != 0 && 1453 (instance->li_flags & LI_RECURSEMASK) != 0) 1454 panic("Lock (%s) %s recursed @ %s:%d.", 1455 lock->lo_class->lc_name, lock->lo_name, file, line); 1456 break; 1457 default: 1458 panic("Invalid lock assertion at %s:%d.", file, line); 1459 1460 } 1461#endif /* INVARIANT_SUPPORT */ 1462} 1463 1464#ifdef DDB 1465 1466DB_SHOW_COMMAND(locks, db_witness_list) 1467{ 1468 struct thread *td; 1469 pid_t pid; 1470 struct proc *p; 1471 1472 if (have_addr) { 1473 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1474 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1475 ((addr >> 16) % 16) * 10000; 1476 /* sx_slock(&allproc_lock); */ 1477 FOREACH_PROC_IN_SYSTEM(p) { 1478 if (p->p_pid == pid) 1479 break; 1480 } 1481 /* sx_sunlock(&allproc_lock); */ 1482 if (p == NULL) { 1483 db_printf("pid %d not found\n", pid); 1484 return; 1485 } 1486 td = &p->p_thread; /* XXXKSE */ 1487 } else { 1488 td = curthread; 1489 } 1490 witness_list(td); 1491} 1492 1493DB_SHOW_COMMAND(witness, db_witness_display) 1494{ 1495 1496 witness_display(db_printf); 1497} 1498#endif 1499