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 * $FreeBSD$ 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 86 struct witness_child_list_entry; 87 88 struct 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 }; 102 103 struct 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 }; 108 109 STAILQ_HEAD(witness_list, witness); 110 111 struct witness_blessed { 112 const char *b_lock1; 113 const char *b_lock2; 114 }; 115 116 struct witness_order_list_entry { 117 const char *w_name; 118 struct lock_class *w_class; 119 }; 120 121 static struct witness *enroll(const char *description, 122 struct lock_class *lock_class); 123 static int itismychild(struct witness *parent, struct witness *child); 124 static void removechild(struct witness *parent, struct witness *child); 125 static int isitmychild(struct witness *parent, struct witness *child); 126 static int isitmydescendant(struct witness *parent, struct witness *child); 127 static int dup_ok(struct witness *); 128 static int blessed(struct witness *, struct witness *); 129 static void witness_display_list(void(*prnt)(const char *fmt, ...), 130 struct witness_list *list); 131 static void witness_displaydescendants(void(*)(const char *fmt, ...), 132 struct witness *); 133 static void witness_leveldescendents(struct witness *parent, int level); 134 static void witness_levelall(void); 135 static struct witness *witness_get(void); 136 static void witness_free(struct witness *m); 137 static struct witness_child_list_entry *witness_child_get(void); 138 static void witness_child_free(struct witness_child_list_entry *wcl); 139 static struct lock_list_entry *witness_lock_list_get(void); 140 static void witness_lock_list_free(struct lock_list_entry *lle); 141 static void witness_display(void(*)(const char *fmt, ...)); 142 static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 143 struct lock_object *lock); 144 145 MALLOC_DEFINE(M_WITNESS, "witness", "witness structure"); 146 147 static int witness_watch = 1; 148 TUNABLE_INT("debug.witness_watch", &witness_watch); 149 SYSCTL_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 159 int witness_ddb = 1; 160 #else 161 int witness_ddb = 0; 162 #endif 163 TUNABLE_INT("debug.witness_ddb", &witness_ddb); 164 SYSCTL_INT(_debug, OID_AUTO, witness_ddb, CTLFLAG_RW, &witness_ddb, 0, ""); 165 #endif /* DDB */ 166 167 #ifdef WITNESS_SKIPSPIN 168 int witness_skipspin = 1; 169 #else 170 int witness_skipspin = 0; 171 #endif 172 TUNABLE_INT("debug.witness_skipspin", &witness_skipspin); 173 SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0, 174 ""); 175 176 static struct mtx w_mtx; 177 static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 178 static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 179 static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 180 static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 181 static struct witness_child_list_entry *w_child_free = NULL; 182 static struct lock_list_entry *w_lock_list_free = NULL; 183 static int witness_dead; /* fatal error, probably no memory */ 184 185 static struct witness w_data[WITNESS_COUNT]; 186 static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 187 static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 188 189 static 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 #ifdef SMP 201 { "ap boot", &lock_class_mtx_spin }, 202 #ifdef __i386__ 203 { "com", &lock_class_mtx_spin }, 204 #endif 205 #endif 206 { "sio", &lock_class_mtx_spin }, 207 #ifdef __i386__ 208 { "cy", &lock_class_mtx_spin }, 209 #endif 210 { "ng_node", &lock_class_mtx_spin }, 211 { "ng_worklist", &lock_class_mtx_spin }, 212 { "ithread table lock", &lock_class_mtx_spin }, 213 { "sched lock", &lock_class_mtx_spin }, 214 { "callout", &lock_class_mtx_spin }, 215 /* 216 * leaf locks 217 */ 218 { "allpmaps", &lock_class_mtx_spin }, 219 { "icu", &lock_class_mtx_spin }, 220 #ifdef SMP 221 { "smp rendezvous", &lock_class_mtx_spin }, 222 #endif 223 { "clk", &lock_class_mtx_spin }, 224 { NULL, NULL }, 225 { NULL, NULL } 226 }; 227 228 static const char *dup_list[] = { 229 "process lock", 230 NULL 231 }; 232 233 /* 234 * Pairs of locks which have been blessed 235 * Don't complain about order problems with blessed locks 236 */ 237 static struct witness_blessed blessed_list[] = { 238 }; 239 static int blessed_count = 240 sizeof(blessed_list) / sizeof(struct witness_blessed); 241 242 /* 243 * List of all locks in the system. 244 */ 245 STAILQ_HEAD(, lock_object) all_locks = STAILQ_HEAD_INITIALIZER(all_locks); 246 247 static struct mtx all_mtx = { 248 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 249 "All locks list", /* mtx_object.lo_name */ 250 LO_INITIALIZED, /* mtx_object.lo_flags */ 251 { NULL }, /* mtx_object.lo_list */ 252 NULL }, /* mtx_object.lo_witness */ 253 MTX_UNOWNED, 0, /* mtx_lock, mtx_recurse */ 254 TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked), 255 { NULL, NULL } /* mtx_contested */ 256 }; 257 258 /* 259 * This global is set to 0 once it becomes safe to use the witness code. 260 */ 261 static int witness_cold = 1; 262 263 /* 264 * Global variables for book keeping. 265 */ 266 static int lock_cur_cnt; 267 static int lock_max_cnt; 268 269 /* 270 * The WITNESS-enabled diagnostic code. 271 */ 272 static void 273 witness_initialize(void *dummy __unused) 274 { 275 struct lock_object *lock; 276 struct witness_order_list_entry *order; 277 struct witness *w, *w1; 278 int i; 279 280 /* 281 * We have to release Giant before initializing its witness 282 * structure so that WITNESS doesn't get confused. 283 */ 284 mtx_unlock(&Giant); 285 mtx_assert(&Giant, MA_NOTOWNED); 286 287 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 288 STAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 289 mtx_init(&w_mtx, "witness lock", MTX_SPIN | MTX_QUIET | MTX_NOWITNESS); 290 for (i = 0; i < WITNESS_COUNT; i++) 291 witness_free(&w_data[i]); 292 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 293 witness_child_free(&w_childdata[i]); 294 for (i = 0; i < LOCK_CHILDCOUNT; i++) 295 witness_lock_list_free(&w_locklistdata[i]); 296 297 /* First add in all the specified order lists. */ 298 for (order = order_lists; order->w_name != NULL; order++) { 299 w = enroll(order->w_name, order->w_class); 300 if (w == NULL) 301 continue; 302 w->w_file = "order list"; 303 for (order++; order->w_name != NULL; order++) { 304 w1 = enroll(order->w_name, order->w_class); 305 if (w1 == NULL) 306 continue; 307 w1->w_file = "order list"; 308 itismychild(w, w1); 309 w = w1; 310 } 311 } 312 313 /* Iterate through all locks and add them to witness. */ 314 mtx_lock(&all_mtx); 315 STAILQ_FOREACH(lock, &all_locks, lo_list) { 316 if (lock->lo_flags & LO_WITNESS) 317 lock->lo_witness = enroll(lock->lo_name, 318 lock->lo_class); 319 else 320 lock->lo_witness = NULL; 321 } 322 mtx_unlock(&all_mtx); 323 324 /* Mark the witness code as being ready for use. */ 325 atomic_store_rel_int(&witness_cold, 0); 326 327 mtx_lock(&Giant); 328 } 329 SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 330 331 void 332 witness_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 } 366 367 void 368 witness_destroy(struct lock_object *lock) 369 { 370 struct witness *w; 371 372 if (witness_cold) 373 panic("lock (%s) %s destroyed while witness_cold", 374 lock->lo_class->lc_name, lock->lo_name); 375 if ((lock->lo_flags & LO_INITIALIZED) == 0) 376 panic("%s: lock (%s) %s is not initialized", __func__, 377 lock->lo_class->lc_name, lock->lo_name); 378 379 /* XXX: need to verify that no one holds the lock */ 380 w = lock->lo_witness; 381 if (w != NULL) { 382 mtx_lock_spin(&w_mtx); 383 w->w_refcount--; 384 if (w->w_refcount == 0) { 385 CTR2(KTR_WITNESS, 386 "%s: marking witness %s as dead", __func__, w->w_name); 387 w->w_name = "(dead)"; 388 w->w_file = "(dead)"; 389 w->w_line = 0; 390 } 391 mtx_unlock_spin(&w_mtx); 392 } 393 394 mtx_lock(&all_mtx); 395 lock_cur_cnt--; 396 STAILQ_REMOVE(&all_locks, lock, lock_object, lo_list); 397 lock->lo_flags &= ~LO_INITIALIZED; 398 mtx_unlock(&all_mtx); 399 } 400 401 static void 402 witness_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 } 426 427 static void 428 witness_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 } 458 459 void 460 witness_lock(struct lock_object *lock, int flags, const char *file, int line) 461 { 462 struct lock_list_entry **lock_list, *lle; 463 struct lock_instance *lock1, *lock2; 464 struct lock_class *class; 465 struct witness *w, *w1; 466 struct thread *td; 467 int i, j; 468 #ifdef DDB 469 int go_into_ddb = 0; 470 #endif /* DDB */ 471 472 if (witness_cold || witness_dead || lock->lo_witness == NULL || 473 panicstr != NULL) 474 return; 475 w = lock->lo_witness; 476 class = lock->lo_class; 477 td = curthread; 478 479 if (class->lc_flags & LC_SLEEPLOCK) { 480 if (td->td_critnest != 0 && (flags & LOP_TRYLOCK) == 0) 481 panic("blockable sleep lock (%s) %s @ %s:%d", 482 class->lc_name, lock->lo_name, file, line); 483 lock_list = &td->td_sleeplocks; 484 } else 485 lock_list = PCPU_PTR(spinlocks); 486 487 /* 488 * Try locks do not block if they fail to acquire the lock, thus 489 * there is no danger of deadlocks or of switching while holding a 490 * spin lock if we acquire a lock via a try operation. 491 */ 492 if (flags & LOP_TRYLOCK) 493 goto out; 494 495 /* 496 * Is this the first lock acquired? If so, then no order checking 497 * is needed. 498 */ 499 if (*lock_list == NULL) 500 goto out; 501 502 /* 503 * Check to see if we are recursing on a lock we already own. 504 */ 505 lock1 = find_instance(*lock_list, lock); 506 if (lock1 != NULL) { 507 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 508 (flags & LOP_EXCLUSIVE) == 0) { 509 printf("shared lock of (%s) %s @ %s:%d\n", 510 class->lc_name, lock->lo_name, file, line); 511 printf("while exclusively locked from %s:%d\n", 512 lock1->li_file, lock1->li_line); 513 panic("share->excl"); 514 } 515 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 516 (flags & LOP_EXCLUSIVE) != 0) { 517 printf("exclusive lock of (%s) %s @ %s:%d\n", 518 class->lc_name, lock->lo_name, file, line); 519 printf("while share locked from %s:%d\n", 520 lock1->li_file, lock1->li_line); 521 panic("excl->share"); 522 } 523 lock1->li_flags++; 524 if ((lock->lo_flags & LO_RECURSABLE) == 0) { 525 printf( 526 "recursed on non-recursive lock (%s) %s @ %s:%d\n", 527 class->lc_name, lock->lo_name, file, line); 528 printf("first acquired @ %s:%d\n", lock1->li_file, 529 lock1->li_line); 530 panic("recurse"); 531 } 532 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 533 td->td_proc->p_pid, lock->lo_name, 534 lock1->li_flags & LI_RECURSEMASK); 535 lock1->li_file = file; 536 lock1->li_line = line; 537 return; 538 } 539 540 /* 541 * Check for duplicate locks of the same type. Note that we only 542 * have to check for this on the last lock we just acquired. Any 543 * other cases will be caught as lock order violations. 544 */ 545 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 546 w1 = lock1->li_lock->lo_witness; 547 if (w1 == w) { 548 if (w->w_same_squawked || dup_ok(w)) 549 goto out; 550 w->w_same_squawked = 1; 551 printf("acquiring duplicate lock of same type: \"%s\"\n", 552 lock->lo_name); 553 printf(" 1st @ %s:%d\n", lock1->li_file, lock1->li_line); 554 printf(" 2nd @ %s:%d\n", file, line); 555 #ifdef DDB 556 go_into_ddb = 1; 557 #endif /* DDB */ 558 goto out; 559 } 560 MPASS(!mtx_owned(&w_mtx)); 561 mtx_lock_spin(&w_mtx); 562 /* 563 * If we have a known higher number just say ok 564 */ 565 if (witness_watch > 1 && w->w_level > w1->w_level) { 566 mtx_unlock_spin(&w_mtx); 567 goto out; 568 } 569 if (isitmydescendant(w1, w)) { 570 mtx_unlock_spin(&w_mtx); 571 goto out; 572 } 573 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 574 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 575 576 MPASS(j < WITNESS_COUNT); 577 lock1 = &lle->ll_children[i]; 578 w1 = lock1->li_lock->lo_witness; 579 580 /* 581 * If this lock doesn't undergo witness checking, 582 * then skip it. 583 */ 584 if (w1 == NULL) { 585 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 586 ("lock missing witness structure")); 587 continue; 588 } 589 /* 590 * If we are locking Giant and we slept with this 591 * lock, then skip it. 592 */ 593 if ((lock1->li_flags & LI_SLEPT) != 0 && 594 lock == &Giant.mtx_object) 595 continue; 596 if (!isitmydescendant(w, w1)) 597 continue; 598 /* 599 * We have a lock order violation, check to see if it 600 * is allowed or has already been yelled about. 601 */ 602 mtx_unlock_spin(&w_mtx); 603 if (blessed(w, w1)) 604 goto out; 605 if (lock1->li_lock == &Giant.mtx_object) { 606 if (w1->w_Giant_squawked) 607 goto out; 608 else 609 w1->w_Giant_squawked = 1; 610 } else { 611 if (w1->w_other_squawked) 612 goto out; 613 else 614 w1->w_other_squawked = 1; 615 } 616 /* 617 * Ok, yell about it. 618 */ 619 printf("lock order reversal\n"); 620 /* 621 * Try to locate an earlier lock with 622 * witness w in our list. 623 */ 624 do { 625 lock2 = &lle->ll_children[i]; 626 MPASS(lock2->li_lock != NULL); 627 if (lock2->li_lock->lo_witness == w) 628 break; 629 i--; 630 if (i == 0 && lle->ll_next != NULL) { 631 lle = lle->ll_next; 632 i = lle->ll_count - 1; 633 MPASS(i != 0); 634 } 635 } while (i >= 0); 636 if (i < 0) { 637 printf(" 1st %p %s @ %s:%d\n", lock1->li_lock, 638 lock1->li_lock->lo_name, lock1->li_file, 639 lock1->li_line); 640 printf(" 2nd %p %s @ %s:%d\n", lock, 641 lock->lo_name, file, line); 642 } else { 643 printf(" 1st %p %s @ %s:%d\n", lock2->li_lock, 644 lock2->li_lock->lo_name, lock2->li_file, 645 lock2->li_line); 646 printf(" 2nd %p %s @ %s:%d\n", lock1->li_lock, 647 lock1->li_lock->lo_name, lock1->li_file, 648 lock1->li_line); 649 printf(" 3rd %p %s @ %s:%d\n", lock, 650 lock->lo_name, file, line); 651 } 652 #ifdef DDB 653 go_into_ddb = 1; 654 #endif /* DDB */ 655 goto out; 656 } 657 } 658 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 659 /* 660 * Don't build a new relationship if we are locking Giant just 661 * after waking up and the previous lock in the list was acquired 662 * prior to blocking. 663 */ 664 if (lock == &Giant.mtx_object && (lock1->li_flags & LI_SLEPT) != 0) 665 mtx_unlock_spin(&w_mtx); 666 else { 667 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 668 lock->lo_name, lock1->li_lock->lo_name); 669 if (!itismychild(lock1->li_lock->lo_witness, w)) 670 mtx_unlock_spin(&w_mtx); 671 } 672 673 out: 674 #ifdef DDB 675 if (witness_ddb && go_into_ddb) 676 Debugger(__func__); 677 #endif /* DDB */ 678 w->w_file = file; 679 w->w_line = line; 680 681 lle = *lock_list; 682 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 683 lle = witness_lock_list_get(); 684 if (lle == NULL) 685 return; 686 lle->ll_next = *lock_list; 687 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 688 td->td_proc->p_pid, lle); 689 *lock_list = lle; 690 } 691 lock1 = &lle->ll_children[lle->ll_count++]; 692 lock1->li_lock = lock; 693 lock1->li_line = line; 694 lock1->li_file = file; 695 if ((flags & LOP_EXCLUSIVE) != 0) 696 lock1->li_flags = LI_EXCLUSIVE; 697 else 698 lock1->li_flags = 0; 699 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 700 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 701 } 702 703 void 704 witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 705 { 706 struct lock_instance *instance; 707 struct lock_class *class; 708 709 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 710 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 711 return; 712 class = lock->lo_class; 713 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 714 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 715 class->lc_name, lock->lo_name, file, line); 716 if ((flags & LOP_TRYLOCK) == 0) 717 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 718 lock->lo_name, file, line); 719 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 720 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 721 class->lc_name, lock->lo_name, file, line); 722 instance = find_instance(curthread->td_sleeplocks, lock); 723 if (instance == NULL) 724 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 725 class->lc_name, lock->lo_name, file, line); 726 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 727 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 728 class->lc_name, lock->lo_name, file, line); 729 if ((instance->li_flags & LI_RECURSEMASK) != 0) 730 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 731 class->lc_name, lock->lo_name, 732 instance->li_flags & LI_RECURSEMASK, file, line); 733 instance->li_flags |= LI_EXCLUSIVE; 734 } 735 736 void 737 witness_downgrade(struct lock_object *lock, int flags, const char *file, 738 int line) 739 { 740 struct lock_instance *instance; 741 struct lock_class *class; 742 743 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 744 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 745 return; 746 class = lock->lo_class; 747 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 748 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 749 class->lc_name, lock->lo_name, file, line); 750 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 751 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 752 class->lc_name, lock->lo_name, file, line); 753 instance = find_instance(curthread->td_sleeplocks, lock); 754 if (instance == NULL) 755 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 756 class->lc_name, lock->lo_name, file, line); 757 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 758 panic("downgrade of shared lock (%s) %s @ %s:%d", 759 class->lc_name, lock->lo_name, file, line); 760 if ((instance->li_flags & LI_RECURSEMASK) != 0) 761 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 762 class->lc_name, lock->lo_name, 763 instance->li_flags & LI_RECURSEMASK, file, line); 764 instance->li_flags &= ~LI_EXCLUSIVE; 765 } 766 767 void 768 witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 769 { 770 struct lock_list_entry **lock_list, *lle; 771 struct lock_instance *instance; 772 struct lock_class *class; 773 struct thread *td; 774 critical_t s; 775 int i, j; 776 777 if (witness_cold || witness_dead || lock->lo_witness == NULL || 778 panicstr != NULL) 779 return; 780 td = curthread; 781 class = lock->lo_class; 782 if (class->lc_flags & LC_SLEEPLOCK) 783 lock_list = &td->td_sleeplocks; 784 else 785 lock_list = PCPU_PTR(spinlocks); 786 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 787 for (i = 0; i < (*lock_list)->ll_count; i++) { 788 instance = &(*lock_list)->ll_children[i]; 789 if (instance->li_lock == lock) { 790 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 791 (flags & LOP_EXCLUSIVE) == 0) { 792 printf( 793 "shared unlock of (%s) %s @ %s:%d\n", 794 class->lc_name, lock->lo_name, 795 file, line); 796 printf( 797 "while exclusively locked from %s:%d\n", 798 instance->li_file, 799 instance->li_line); 800 panic("excl->ushare"); 801 } 802 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 803 (flags & LOP_EXCLUSIVE) != 0) { 804 printf( 805 "exclusive unlock of (%s) %s @ %s:%d\n", 806 class->lc_name, lock->lo_name, 807 file, line); 808 printf( 809 "while share locked from %s:%d\n", 810 instance->li_file, 811 instance->li_line); 812 panic("share->uexcl"); 813 } 814 /* If we are recursed, unrecurse. */ 815 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 816 CTR4(KTR_WITNESS, 817 "%s: pid %d unrecursed on %s r=%d", __func__, 818 td->td_proc->p_pid, 819 instance->li_lock->lo_name, 820 instance->li_flags); 821 instance->li_flags--; 822 return; 823 } 824 s = cpu_critical_enter(); 825 CTR4(KTR_WITNESS, 826 "%s: pid %d removed %s from lle[%d]", __func__, 827 td->td_proc->p_pid, 828 instance->li_lock->lo_name, 829 (*lock_list)->ll_count - 1); 830 (*lock_list)->ll_count--; 831 for (j = i; j < (*lock_list)->ll_count; j++) 832 (*lock_list)->ll_children[j] = 833 (*lock_list)->ll_children[j + 1]; 834 cpu_critical_exit(s); 835 if ((*lock_list)->ll_count == 0) { 836 lle = *lock_list; 837 *lock_list = lle->ll_next; 838 CTR3(KTR_WITNESS, 839 "%s: pid %d removed lle %p", __func__, 840 td->td_proc->p_pid, lle); 841 witness_lock_list_free(lle); 842 } 843 return; 844 } 845 } 846 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 847 file, line); 848 } 849 850 /* 851 * Warn if any held locks are not sleepable. Note that Giant and the lock 852 * passed in are both special cases since they are both released during the 853 * sleep process and aren't actually held while the thread is asleep. 854 */ 855 int 856 witness_sleep(int check_only, struct lock_object *lock, const char *file, 857 int line) 858 { 859 struct lock_list_entry **lock_list, *lle; 860 struct lock_instance *lock1; 861 struct thread *td; 862 critical_t savecrit; 863 int i, n; 864 865 if (witness_dead || panicstr != NULL) 866 return (0); 867 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 868 n = 0; 869 /* 870 * Preemption bad because we need PCPU_PTR(spinlocks) to not change. 871 */ 872 savecrit = cpu_critical_enter(); 873 td = curthread; 874 lock_list = &td->td_sleeplocks; 875 again: 876 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 877 for (i = lle->ll_count - 1; i >= 0; i--) { 878 lock1 = &lle->ll_children[i]; 879 if (lock1->li_lock == lock || 880 lock1->li_lock == &Giant.mtx_object) 881 continue; 882 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) { 883 if (check_only == 0) { 884 CTR3(KTR_WITNESS, 885 "pid %d: sleeping with lock (%s) %s held", 886 td->td_proc->p_pid, 887 lock1->li_lock->lo_class->lc_name, 888 lock1->li_lock->lo_name); 889 lock1->li_flags |= LI_SLEPT; 890 } 891 continue; 892 } 893 n++; 894 printf("%s:%d: %s with \"%s\" locked from %s:%d\n", 895 file, line, check_only ? "could sleep" : "sleeping", 896 lock1->li_lock->lo_name, lock1->li_file, 897 lock1->li_line); 898 } 899 if (lock_list == &td->td_sleeplocks) { 900 lock_list = PCPU_PTR(spinlocks); 901 goto again; 902 } 903 #ifdef DDB 904 if (witness_ddb && n) 905 Debugger(__func__); 906 #endif /* DDB */ 907 cpu_critical_exit(savecrit); 908 return (n); 909 } 910 911 static struct witness * 912 enroll(const char *description, struct lock_class *lock_class) 913 { 914 struct witness *w; 915 916 if (!witness_watch || witness_dead || panicstr != NULL) 917 return (NULL); 918 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 919 return (NULL); 920 mtx_lock_spin(&w_mtx); 921 STAILQ_FOREACH(w, &w_all, w_list) { 922 if (strcmp(description, w->w_name) == 0) { 923 w->w_refcount++; 924 mtx_unlock_spin(&w_mtx); 925 if (lock_class != w->w_class) 926 panic( 927 "lock (%s) %s does not match earlier (%s) lock", 928 description, lock_class->lc_name, 929 w->w_class->lc_name); 930 return (w); 931 } 932 } 933 /* 934 * This isn't quite right, as witness_cold is still 0 while we 935 * enroll all the locks initialized before witness_initialize(). 936 */ 937 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 938 mtx_unlock_spin(&w_mtx); 939 panic("spin lock %s not in order list", description); 940 } 941 if ((w = witness_get()) == NULL) 942 return (NULL); 943 w->w_name = description; 944 w->w_class = lock_class; 945 w->w_refcount = 1; 946 STAILQ_INSERT_HEAD(&w_all, w, w_list); 947 if (lock_class->lc_flags & LC_SPINLOCK) 948 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 949 else if (lock_class->lc_flags & LC_SLEEPLOCK) 950 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 951 else { 952 mtx_unlock_spin(&w_mtx); 953 panic("lock class %s is not sleep or spin", 954 lock_class->lc_name); 955 } 956 mtx_unlock_spin(&w_mtx); 957 return (w); 958 } 959 960 static int 961 itismychild(struct witness *parent, struct witness *child) 962 { 963 static int recursed; 964 struct witness_child_list_entry **wcl; 965 struct witness_list *list; 966 967 MPASS(child != NULL && parent != NULL); 968 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 969 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 970 panic( 971 "%s: parent (%s) and child (%s) are not the same lock type", 972 __func__, parent->w_class->lc_name, 973 child->w_class->lc_name); 974 975 /* 976 * Insert "child" after "parent" 977 */ 978 wcl = &parent->w_children; 979 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 980 wcl = &(*wcl)->wcl_next; 981 if (*wcl == NULL) { 982 *wcl = witness_child_get(); 983 if (*wcl == NULL) 984 return (1); 985 } 986 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 987 988 /* 989 * Now prune whole tree. We look for cases where a lock is now 990 * both a descendant and a direct child of a given lock. In that 991 * case, we want to remove the direct child link from the tree. 992 */ 993 if (recursed) 994 return (0); 995 recursed = 1; 996 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 997 list = &w_sleep; 998 else 999 list = &w_spin; 1000 STAILQ_FOREACH(child, list, w_typelist) { 1001 STAILQ_FOREACH(parent, list, w_typelist) { 1002 if (!isitmychild(parent, child)) 1003 continue; 1004 removechild(parent, child); 1005 if (isitmydescendant(parent, child)) 1006 continue; 1007 itismychild(parent, child); 1008 } 1009 } 1010 recursed = 0; 1011 witness_levelall(); 1012 return (0); 1013 } 1014 1015 static void 1016 removechild(struct witness *parent, struct witness *child) 1017 { 1018 struct witness_child_list_entry **wcl, *wcl1; 1019 int i; 1020 1021 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1022 for (i = 0; i < (*wcl)->wcl_count; i++) 1023 if ((*wcl)->wcl_children[i] == child) 1024 goto found; 1025 return; 1026 found: 1027 (*wcl)->wcl_count--; 1028 if ((*wcl)->wcl_count > i) 1029 (*wcl)->wcl_children[i] = 1030 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1031 MPASS((*wcl)->wcl_children[i] != NULL); 1032 if ((*wcl)->wcl_count != 0) 1033 return; 1034 wcl1 = *wcl; 1035 *wcl = wcl1->wcl_next; 1036 witness_child_free(wcl1); 1037 } 1038 1039 static int 1040 isitmychild(struct witness *parent, struct witness *child) 1041 { 1042 struct witness_child_list_entry *wcl; 1043 int i; 1044 1045 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1046 for (i = 0; i < wcl->wcl_count; i++) { 1047 if (wcl->wcl_children[i] == child) 1048 return (1); 1049 } 1050 } 1051 return (0); 1052 } 1053 1054 static int 1055 isitmydescendant(struct witness *parent, struct witness *child) 1056 { 1057 struct witness_child_list_entry *wcl; 1058 int i, j; 1059 1060 if (isitmychild(parent, child)) 1061 return (1); 1062 j = 0; 1063 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1064 MPASS(j < 1000); 1065 for (i = 0; i < wcl->wcl_count; i++) { 1066 if (isitmydescendant(wcl->wcl_children[i], child)) 1067 return (1); 1068 } 1069 j++; 1070 } 1071 return (0); 1072 } 1073 1074 void 1075 witness_levelall (void) 1076 { 1077 struct witness_list *list; 1078 struct witness *w, *w1; 1079 1080 /* 1081 * First clear all levels. 1082 */ 1083 STAILQ_FOREACH(w, &w_all, w_list) { 1084 w->w_level = 0; 1085 } 1086 1087 /* 1088 * Look for locks with no parent and level all their descendants. 1089 */ 1090 STAILQ_FOREACH(w, &w_all, w_list) { 1091 /* 1092 * This is just an optimization, technically we could get 1093 * away just walking the all list each time. 1094 */ 1095 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1096 list = &w_sleep; 1097 else 1098 list = &w_spin; 1099 STAILQ_FOREACH(w1, list, w_typelist) { 1100 if (isitmychild(w1, w)) 1101 goto skip; 1102 } 1103 witness_leveldescendents(w, 0); 1104 skip: 1105 } 1106 } 1107 1108 static void 1109 witness_leveldescendents(struct witness *parent, int level) 1110 { 1111 struct witness_child_list_entry *wcl; 1112 int i; 1113 1114 if (parent->w_level < level) 1115 parent->w_level = level; 1116 level++; 1117 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1118 for (i = 0; i < wcl->wcl_count; i++) 1119 witness_leveldescendents(wcl->wcl_children[i], level); 1120 } 1121 1122 static void 1123 witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1124 struct witness *parent) 1125 { 1126 struct witness_child_list_entry *wcl; 1127 int i, level; 1128 1129 level = parent->w_level; 1130 prnt("%-2d", level); 1131 for (i = 0; i < level; i++) 1132 prnt(" "); 1133 prnt("%s", parent->w_name); 1134 if (parent->w_file != NULL) 1135 prnt(" -- last acquired @ %s:%d\n", parent->w_file, 1136 parent->w_line); 1137 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1138 for (i = 0; i < wcl->wcl_count; i++) 1139 witness_displaydescendants(prnt, 1140 wcl->wcl_children[i]); 1141 } 1142 1143 static int 1144 dup_ok(struct witness *w) 1145 { 1146 const char **dup; 1147 1148 for (dup = dup_list; *dup != NULL; dup++) 1149 if (strcmp(w->w_name, *dup) == 0) 1150 return (1); 1151 return (0); 1152 } 1153 1154 static int 1155 blessed(struct witness *w1, struct witness *w2) 1156 { 1157 int i; 1158 struct witness_blessed *b; 1159 1160 for (i = 0; i < blessed_count; i++) { 1161 b = &blessed_list[i]; 1162 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1163 if (strcmp(w2->w_name, b->b_lock2) == 0) 1164 return (1); 1165 continue; 1166 } 1167 if (strcmp(w1->w_name, b->b_lock2) == 0) 1168 if (strcmp(w2->w_name, b->b_lock1) == 0) 1169 return (1); 1170 } 1171 return (0); 1172 } 1173 1174 static struct witness * 1175 witness_get(void) 1176 { 1177 struct witness *w; 1178 1179 if (witness_dead) { 1180 mtx_unlock_spin(&w_mtx); 1181 return (NULL); 1182 } 1183 if (STAILQ_EMPTY(&w_free)) { 1184 witness_dead = 1; 1185 mtx_unlock_spin(&w_mtx); 1186 printf("%s: witness exhausted\n", __func__); 1187 return (NULL); 1188 } 1189 w = STAILQ_FIRST(&w_free); 1190 STAILQ_REMOVE_HEAD(&w_free, w_list); 1191 bzero(w, sizeof(*w)); 1192 return (w); 1193 } 1194 1195 static void 1196 witness_free(struct witness *w) 1197 { 1198 1199 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1200 } 1201 1202 static struct witness_child_list_entry * 1203 witness_child_get(void) 1204 { 1205 struct witness_child_list_entry *wcl; 1206 1207 if (witness_dead) { 1208 mtx_unlock_spin(&w_mtx); 1209 return (NULL); 1210 } 1211 wcl = w_child_free; 1212 if (wcl == NULL) { 1213 witness_dead = 1; 1214 mtx_unlock_spin(&w_mtx); 1215 printf("%s: witness exhausted\n", __func__); 1216 return (NULL); 1217 } 1218 w_child_free = wcl->wcl_next; 1219 bzero(wcl, sizeof(*wcl)); 1220 return (wcl); 1221 } 1222 1223 static void 1224 witness_child_free(struct witness_child_list_entry *wcl) 1225 { 1226 1227 wcl->wcl_next = w_child_free; 1228 w_child_free = wcl; 1229 } 1230 1231 static struct lock_list_entry * 1232 witness_lock_list_get(void) 1233 { 1234 struct lock_list_entry *lle; 1235 1236 if (witness_dead) 1237 return (NULL); 1238 mtx_lock_spin(&w_mtx); 1239 lle = w_lock_list_free; 1240 if (lle == NULL) { 1241 witness_dead = 1; 1242 mtx_unlock_spin(&w_mtx); 1243 printf("%s: witness exhausted\n", __func__); 1244 return (NULL); 1245 } 1246 w_lock_list_free = lle->ll_next; 1247 mtx_unlock_spin(&w_mtx); 1248 bzero(lle, sizeof(*lle)); 1249 return (lle); 1250 } 1251 1252 static void 1253 witness_lock_list_free(struct lock_list_entry *lle) 1254 { 1255 1256 mtx_lock_spin(&w_mtx); 1257 lle->ll_next = w_lock_list_free; 1258 w_lock_list_free = lle; 1259 mtx_unlock_spin(&w_mtx); 1260 } 1261 1262 static struct lock_instance * 1263 find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1264 { 1265 struct lock_list_entry *lle; 1266 struct lock_instance *instance; 1267 int i; 1268 1269 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1270 for (i = lle->ll_count - 1; i >= 0; i--) { 1271 instance = &lle->ll_children[i]; 1272 if (instance->li_lock == lock) 1273 return (instance); 1274 } 1275 return (NULL); 1276 } 1277 1278 int 1279 witness_list_locks(struct lock_list_entry **lock_list) 1280 { 1281 struct lock_list_entry *lle; 1282 struct lock_instance *instance; 1283 struct lock_object *lock; 1284 int i, nheld; 1285 1286 nheld = 0; 1287 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1288 for (i = lle->ll_count - 1; i >= 0; i--) { 1289 instance = &lle->ll_children[i]; 1290 lock = instance->li_lock; 1291 printf("%s (%s) %s (%p) locked @ %s:%d\n", 1292 (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1293 "exclusive" : "shared", 1294 lock->lo_class->lc_name, lock->lo_name, lock, 1295 instance->li_file, instance->li_line); 1296 nheld++; 1297 } 1298 return (nheld); 1299 } 1300 1301 /* 1302 * Calling this on td != curthread is bad unless we are in ddb. 1303 */ 1304 int 1305 witness_list(struct thread *td) 1306 { 1307 critical_t savecrit; 1308 int nheld; 1309 1310 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1311 #ifdef DDB 1312 KASSERT(td == curthread || db_active, 1313 ("%s: td != curthread and we aren't in the debugger", __func__)); 1314 if (!db_active && witness_dead) 1315 return (0); 1316 #else 1317 KASSERT(td == curthread, ("%s: p != curthread", __func__)); 1318 if (witness_dead) 1319 return (0); 1320 #endif 1321 nheld = witness_list_locks(&td->td_sleeplocks); 1322 1323 /* 1324 * We only handle spinlocks if td == curthread. This is somewhat broken 1325 * if td is currently executing on some other CPU and holds spin locks 1326 * as we won't display those locks. If we had a MI way of getting 1327 * the per-cpu data for a given cpu then we could use 1328 * td->td_kse->ke_oncpu to get the list of spinlocks for this thread 1329 * and "fix" this. 1330 */ 1331 if (td == curthread) { 1332 /* 1333 * Preemption bad because we need PCPU_PTR(spinlocks) to not 1334 * change. 1335 */ 1336 savecrit = cpu_critical_enter(); 1337 nheld += witness_list_locks(PCPU_PTR(spinlocks)); 1338 cpu_critical_exit(savecrit); 1339 } 1340 return (nheld); 1341 } 1342 1343 void 1344 witness_save(struct lock_object *lock, const char **filep, int *linep) 1345 { 1346 struct lock_instance *instance; 1347 1348 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1349 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1350 return; 1351 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1352 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1353 lock->lo_class->lc_name, lock->lo_name); 1354 instance = find_instance(curthread->td_sleeplocks, lock); 1355 if (instance == NULL) 1356 panic("%s: lock (%s) %s not locked", __func__, 1357 lock->lo_class->lc_name, lock->lo_name); 1358 *filep = instance->li_file; 1359 *linep = instance->li_line; 1360 } 1361 1362 void 1363 witness_restore(struct lock_object *lock, const char *file, int line) 1364 { 1365 struct lock_instance *instance; 1366 1367 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1368 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1369 return; 1370 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1371 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1372 lock->lo_class->lc_name, lock->lo_name); 1373 instance = find_instance(curthread->td_sleeplocks, lock); 1374 if (instance == NULL) 1375 panic("%s: lock (%s) %s not locked", __func__, 1376 lock->lo_class->lc_name, lock->lo_name); 1377 lock->lo_witness->w_file = file; 1378 lock->lo_witness->w_line = line; 1379 instance->li_file = file; 1380 instance->li_line = line; 1381 } 1382 1383 void 1384 witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1385 { 1386 #ifdef INVARIANT_SUPPORT 1387 struct lock_instance *instance; 1388 1389 if (lock->lo_witness == NULL || witness_dead || panicstr != NULL) 1390 return; 1391 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1392 instance = find_instance(curthread->td_sleeplocks, lock); 1393 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1394 instance = find_instance(PCPU_GET(spinlocks), lock); 1395 else { 1396 panic("Lock (%s) %s is not sleep or spin!", 1397 lock->lo_class->lc_name, lock->lo_name); 1398 return; 1399 } 1400 switch (flags) { 1401 case LA_UNLOCKED: 1402 if (instance != NULL) 1403 panic("Lock (%s) %s locked @ %s:%d.", 1404 lock->lo_class->lc_name, lock->lo_name, file, line); 1405 break; 1406 case LA_LOCKED: 1407 case LA_LOCKED | LA_RECURSED: 1408 case LA_LOCKED | LA_NOTRECURSED: 1409 case LA_SLOCKED: 1410 case LA_SLOCKED | LA_RECURSED: 1411 case LA_SLOCKED | LA_NOTRECURSED: 1412 case LA_XLOCKED: 1413 case LA_XLOCKED | LA_RECURSED: 1414 case LA_XLOCKED | LA_NOTRECURSED: 1415 if (instance == NULL) { 1416 panic("Lock (%s) %s not locked @ %s:%d.", 1417 lock->lo_class->lc_name, lock->lo_name, file, line); 1418 break; 1419 } 1420 if ((flags & LA_XLOCKED) != 0 && 1421 (instance->li_flags & LI_EXCLUSIVE) == 0) 1422 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1423 lock->lo_class->lc_name, lock->lo_name, file, line); 1424 if ((flags & LA_SLOCKED) != 0 && 1425 (instance->li_flags & LI_EXCLUSIVE) != 0) 1426 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1427 lock->lo_class->lc_name, lock->lo_name, file, line); 1428 if ((flags & LA_RECURSED) != 0 && 1429 (instance->li_flags & LI_RECURSEMASK) == 0) 1430 panic("Lock (%s) %s not recursed @ %s:%d.", 1431 lock->lo_class->lc_name, lock->lo_name, file, line); 1432 if ((flags & LA_NOTRECURSED) != 0 && 1433 (instance->li_flags & LI_RECURSEMASK) != 0) 1434 panic("Lock (%s) %s recursed @ %s:%d.", 1435 lock->lo_class->lc_name, lock->lo_name, file, line); 1436 break; 1437 default: 1438 panic("Invalid lock assertion at %s:%d.", file, line); 1439 1440 } 1441 #endif /* INVARIANT_SUPPORT */ 1442 } 1443 1444 #ifdef DDB 1445 1446 DB_SHOW_COMMAND(locks, db_witness_list) 1447 { 1448 struct thread *td; 1449 pid_t pid; 1450 struct proc *p; 1451 1452 if (have_addr) { 1453 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1454 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1455 ((addr >> 16) % 16) * 10000; 1456 /* sx_slock(&allproc_lock); */ 1457 FOREACH_PROC_IN_SYSTEM(p) { 1458 if (p->p_pid == pid) 1459 break; 1460 } 1461 /* sx_sunlock(&allproc_lock); */ 1462 if (p == NULL) { 1463 db_printf("pid %d not found\n", pid); 1464 return; 1465 } 1466 FOREACH_THREAD_IN_PROC(p, td) { 1467 witness_list(td); 1468 } 1469 } else { 1470 td = curthread; 1471 witness_list(td); 1472 } 1473 } 1474 1475 DB_SHOW_COMMAND(witness, db_witness_display) 1476 { 1477 1478 witness_display(db_printf); 1479 } 1480 #endif 1481