Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_witness.c
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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 */ 31 32 /* 33 * Implementation of the `witness' lock verifier. Originally implemented for 34 * mutexes in BSD/OS. Extended to handle generic lock objects and lock 35 * classes in FreeBSD. 36 */ 37 38 /* 39 * Main Entry: witness 40 * Pronunciation: 'wit-n&s 41 * Function: noun 42 * Etymology: Middle English witnesse, from Old English witnes knowledge, 43 * testimony, witness, from 2wit 44 * Date: before 12th century 45 * 1 : attestation of a fact or event : TESTIMONY 46 * 2 : one that gives evidence; specifically : one who testifies in 47 * a cause or before a judicial tribunal 48 * 3 : one asked to be present at a transaction so as to be able to 49 * testify to its having taken place 50 * 4 : one who has personal knowledge of something 51 * 5 a : something serving as evidence or proof : SIGN 52 * b : public affirmation by word or example of usually 53 * religious faith or conviction <the heroic witness to divine 54 * life -- Pilot> 55 * 6 capitalized : a member of the Jehovah's Witnesses 56 */ 57 58 /* 59 * Special rules concerning Giant and lock orders: 60 * 61 * 1) Giant must be acquired before any other mutexes. Stated another way, 62 * no other mutex may be held when Giant is acquired. 63 * 64 * 2) Giant must be released when blocking on a sleepable lock. 65 * 66 * This rule is less obvious, but is a result of Giant providing the same 67 * semantics as spl(). Basically, when a thread sleeps, it must release 68 * Giant. When a thread blocks on a sleepable lock, it sleeps. Hence rule 69 * 2). 70 * 71 * 3) Giant may be acquired before or after sleepable locks. 72 * 73 * This rule is also not quite as obvious. Giant may be acquired after 74 * a sleepable lock because it is a non-sleepable lock and non-sleepable 75 * locks may always be acquired while holding a sleepable lock. The second 76 * case, Giant before a sleepable lock, follows from rule 2) above. Suppose 77 * you have two threads T1 and T2 and a sleepable lock X. Suppose that T1 78 * acquires X and blocks on Giant. Then suppose that T2 acquires Giant and 79 * blocks on X. When T2 blocks on X, T2 will release Giant allowing T1 to 80 * execute. Thus, acquiring Giant both before and after a sleepable lock 81 * will not result in a lock order reversal. 82 */ 83 84 #include <sys/cdefs.h> 85 __FBSDID("$FreeBSD: src/sys/kern/subr_witness.c,v 1.178.2.10 2006/01/26 02:33:36 truckman Exp $"); 86 87 #include "opt_ddb.h" 88 #include "opt_witness.h" 89 90 #include <sys/param.h> 91 #include <sys/bus.h> 92 #include <sys/kdb.h> 93 #include <sys/kernel.h> 94 #include <sys/ktr.h> 95 #include <sys/lock.h> 96 #include <sys/malloc.h> 97 #include <sys/mutex.h> 98 #include <sys/proc.h> 99 #include <sys/sysctl.h> 100 #include <sys/systm.h> 101 102 #include <ddb/ddb.h> 103 104 #include <machine/stdarg.h> 105 106 /* Define this to check for blessed mutexes */ 107 #undef BLESSING 108 109 #define WITNESS_COUNT 200 110 #define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4) 111 /* 112 * XXX: This is somewhat bogus, as we assume here that at most 1024 threads 113 * will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should 114 * probably be safe for the most part, but it's still a SWAG. 115 */ 116 #define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2 117 118 #define WITNESS_NCHILDREN 6 119 120 struct witness_child_list_entry; 121 122 struct witness { 123 const char *w_name; 124 struct lock_class *w_class; 125 STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */ 126 STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ 127 struct witness_child_list_entry *w_children; /* Great evilness... */ 128 const char *w_file; 129 int w_line; 130 u_int w_level; 131 u_int w_refcount; 132 u_char w_Giant_squawked:1; 133 u_char w_other_squawked:1; 134 u_char w_same_squawked:1; 135 u_char w_displayed:1; 136 }; 137 138 struct witness_child_list_entry { 139 struct witness_child_list_entry *wcl_next; 140 struct witness *wcl_children[WITNESS_NCHILDREN]; 141 u_int wcl_count; 142 }; 143 144 STAILQ_HEAD(witness_list, witness); 145 146 #ifdef BLESSING 147 struct witness_blessed { 148 const char *b_lock1; 149 const char *b_lock2; 150 }; 151 #endif 152 153 struct witness_order_list_entry { 154 const char *w_name; 155 struct lock_class *w_class; 156 }; 157 158 #ifdef BLESSING 159 static int blessed(struct witness *, struct witness *); 160 #endif 161 static int depart(struct witness *w); 162 static struct witness *enroll(const char *description, 163 struct lock_class *lock_class); 164 static int insertchild(struct witness *parent, struct witness *child); 165 static int isitmychild(struct witness *parent, struct witness *child); 166 static int isitmydescendant(struct witness *parent, struct witness *child); 167 static int itismychild(struct witness *parent, struct witness *child); 168 static void removechild(struct witness *parent, struct witness *child); 169 static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS); 170 static const char *fixup_filename(const char *file); 171 static struct witness *witness_get(void); 172 static void witness_free(struct witness *m); 173 static struct witness_child_list_entry *witness_child_get(void); 174 static void witness_child_free(struct witness_child_list_entry *wcl); 175 static struct lock_list_entry *witness_lock_list_get(void); 176 static void witness_lock_list_free(struct lock_list_entry *lle); 177 static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 178 struct lock_object *lock); 179 static void witness_list_lock(struct lock_instance *instance); 180 #ifdef DDB 181 static void witness_leveldescendents(struct witness *parent, int level); 182 static void witness_levelall(void); 183 static void witness_displaydescendants(void(*)(const char *fmt, ...), 184 struct witness *, int indent); 185 static void witness_display_list(void(*prnt)(const char *fmt, ...), 186 struct witness_list *list); 187 static void witness_display(void(*)(const char *fmt, ...)); 188 static void witness_list(struct thread *td); 189 #endif 190 191 SYSCTL_NODE(_debug, OID_AUTO, witness, CTLFLAG_RW, 0, "Witness Locking"); 192 193 /* 194 * If set to 0, witness is disabled. If set to a non-zero value, witness 195 * performs full lock order checking for all locks. At runtime, this 196 * value may be set to 0 to turn off witness. witness is not allowed be 197 * turned on once it is turned off, however. 198 */ 199 static int witness_watch = 1; 200 TUNABLE_INT("debug.witness.watch", &witness_watch); 201 SYSCTL_PROC(_debug_witness, OID_AUTO, watch, CTLFLAG_RW | CTLTYPE_INT, NULL, 0, 202 sysctl_debug_witness_watch, "I", "witness is watching lock operations"); 203 204 #ifdef KDB 205 /* 206 * When KDB is enabled and witness_kdb is set to 1, it will cause the system 207 * to drop into kdebug() when: 208 * - a lock heirarchy violation occurs 209 * - locks are held when going to sleep. 210 */ 211 #ifdef WITNESS_KDB 212 int witness_kdb = 1; 213 #else 214 int witness_kdb = 0; 215 #endif 216 TUNABLE_INT("debug.witness.kdb", &witness_kdb); 217 SYSCTL_INT(_debug_witness, OID_AUTO, kdb, CTLFLAG_RW, &witness_kdb, 0, ""); 218 219 /* 220 * When KDB is enabled and witness_trace is set to 1, it will cause the system 221 * to print a stack trace: 222 * - a lock heirarchy violation occurs 223 * - locks are held when going to sleep. 224 */ 225 int witness_trace = 1; 226 TUNABLE_INT("debug.witness.trace", &witness_trace); 227 SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, ""); 228 #endif /* KDB */ 229 230 #ifdef WITNESS_SKIPSPIN 231 int witness_skipspin = 1; 232 #else 233 int witness_skipspin = 0; 234 #endif 235 TUNABLE_INT("debug.witness.skipspin", &witness_skipspin); 236 SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN, 237 &witness_skipspin, 0, ""); 238 239 static struct mtx w_mtx; 240 static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 241 static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 242 static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 243 static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 244 static struct witness_child_list_entry *w_child_free = NULL; 245 static struct lock_list_entry *w_lock_list_free = NULL; 246 247 static int w_free_cnt, w_spin_cnt, w_sleep_cnt, w_child_free_cnt, w_child_cnt; 248 SYSCTL_INT(_debug_witness, OID_AUTO, free_cnt, CTLFLAG_RD, &w_free_cnt, 0, ""); 249 SYSCTL_INT(_debug_witness, OID_AUTO, spin_cnt, CTLFLAG_RD, &w_spin_cnt, 0, ""); 250 SYSCTL_INT(_debug_witness, OID_AUTO, sleep_cnt, CTLFLAG_RD, &w_sleep_cnt, 0, 251 ""); 252 SYSCTL_INT(_debug_witness, OID_AUTO, child_free_cnt, CTLFLAG_RD, 253 &w_child_free_cnt, 0, ""); 254 SYSCTL_INT(_debug_witness, OID_AUTO, child_cnt, CTLFLAG_RD, &w_child_cnt, 0, 255 ""); 256 257 static struct witness w_data[WITNESS_COUNT]; 258 static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 259 static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 260 261 static struct witness_order_list_entry order_lists[] = { 262 { "proctree", &lock_class_sx }, 263 { "allproc", &lock_class_sx }, 264 { "Giant", &lock_class_mtx_sleep }, 265 { "filedesc structure", &lock_class_mtx_sleep }, 266 { "pipe mutex", &lock_class_mtx_sleep }, 267 { "sigio lock", &lock_class_mtx_sleep }, 268 { "process group", &lock_class_mtx_sleep }, 269 { "process lock", &lock_class_mtx_sleep }, 270 { "session", &lock_class_mtx_sleep }, 271 { "uidinfo hash", &lock_class_mtx_sleep }, 272 { "uidinfo struct", &lock_class_mtx_sleep }, 273 { "allprison", &lock_class_mtx_sleep }, 274 { NULL, NULL }, 275 /* 276 * Sockets 277 */ 278 { "filedesc structure", &lock_class_mtx_sleep }, 279 { "accept", &lock_class_mtx_sleep }, 280 { "so_snd", &lock_class_mtx_sleep }, 281 { "so_rcv", &lock_class_mtx_sleep }, 282 { "sellck", &lock_class_mtx_sleep }, 283 { NULL, NULL }, 284 /* 285 * Routing 286 */ 287 { "so_rcv", &lock_class_mtx_sleep }, 288 { "radix node head", &lock_class_mtx_sleep }, 289 { "rtentry", &lock_class_mtx_sleep }, 290 { "ifaddr", &lock_class_mtx_sleep }, 291 { NULL, NULL }, 292 /* 293 * Multicast - protocol locks before interface locks. 294 */ 295 { "in_multi_mtx", &lock_class_mtx_sleep }, 296 { "igmp_mtx", &lock_class_mtx_sleep }, 297 { "if_addr_mtx", &lock_class_mtx_sleep }, 298 { NULL, NULL }, 299 /* 300 * UNIX Domain Sockets 301 */ 302 { "unp", &lock_class_mtx_sleep }, 303 { "so_snd", &lock_class_mtx_sleep }, 304 { NULL, NULL }, 305 /* 306 * UDP/IP 307 */ 308 { "udp", &lock_class_mtx_sleep }, 309 { "udpinp", &lock_class_mtx_sleep }, 310 { "so_snd", &lock_class_mtx_sleep }, 311 { NULL, NULL }, 312 /* 313 * TCP/IP 314 */ 315 { "tcp", &lock_class_mtx_sleep }, 316 { "tcpinp", &lock_class_mtx_sleep }, 317 { "so_snd", &lock_class_mtx_sleep }, 318 { NULL, NULL }, 319 /* 320 * SLIP 321 */ 322 { "slip_mtx", &lock_class_mtx_sleep }, 323 { "slip sc_mtx", &lock_class_mtx_sleep }, 324 { NULL, NULL }, 325 /* 326 * netatalk 327 */ 328 { "ddp_list_mtx", &lock_class_mtx_sleep }, 329 { "ddp_mtx", &lock_class_mtx_sleep }, 330 { NULL, NULL }, 331 /* 332 * BPF 333 */ 334 { "bpf global lock", &lock_class_mtx_sleep }, 335 { "bpf interface lock", &lock_class_mtx_sleep }, 336 { "bpf cdev lock", &lock_class_mtx_sleep }, 337 { NULL, NULL }, 338 /* 339 * spin locks 340 */ 341 #ifdef SMP 342 { "ap boot", &lock_class_mtx_spin }, 343 #endif 344 { "sio", &lock_class_mtx_spin }, 345 #ifdef __i386__ 346 { "cy", &lock_class_mtx_spin }, 347 #endif 348 { "uart_hwmtx", &lock_class_mtx_spin }, 349 { "sabtty", &lock_class_mtx_spin }, 350 { "zstty", &lock_class_mtx_spin }, 351 { "ng_node", &lock_class_mtx_spin }, 352 { "ng_worklist", &lock_class_mtx_spin }, 353 { "taskqueue_fast", &lock_class_mtx_spin }, 354 { "intr table", &lock_class_mtx_spin }, 355 { "ithread table lock", &lock_class_mtx_spin }, 356 { "sleepq chain", &lock_class_mtx_spin }, 357 { "sched lock", &lock_class_mtx_spin }, 358 { "turnstile chain", &lock_class_mtx_spin }, 359 { "td_contested", &lock_class_mtx_spin }, 360 { "callout", &lock_class_mtx_spin }, 361 { "entropy harvest mutex", &lock_class_mtx_spin }, 362 /* 363 * leaf locks 364 */ 365 { "allpmaps", &lock_class_mtx_spin }, 366 { "vm page queue free mutex", &lock_class_mtx_spin }, 367 { "icu", &lock_class_mtx_spin }, 368 #ifdef SMP 369 { "smp rendezvous", &lock_class_mtx_spin }, 370 #if defined(__i386__) || defined(__amd64__) 371 { "tlb", &lock_class_mtx_spin }, 372 #endif 373 #ifdef __sparc64__ 374 { "ipi", &lock_class_mtx_spin }, 375 #endif 376 #endif 377 { "clk", &lock_class_mtx_spin }, 378 { "mutex profiling lock", &lock_class_mtx_spin }, 379 { "kse zombie lock", &lock_class_mtx_spin }, 380 { "ALD Queue", &lock_class_mtx_spin }, 381 #ifdef __ia64__ 382 { "MCA spin lock", &lock_class_mtx_spin }, 383 #endif 384 #if defined(__i386__) || defined(__amd64__) 385 { "pcicfg", &lock_class_mtx_spin }, 386 #endif 387 { "tw_osl_io_lock", &lock_class_mtx_spin }, 388 { "tw_osl_q_lock", &lock_class_mtx_spin }, 389 { "tw_cl_io_lock", &lock_class_mtx_spin }, 390 { "tw_cl_intr_lock", &lock_class_mtx_spin }, 391 { "tw_cl_gen_lock", &lock_class_mtx_spin }, 392 { NULL, NULL }, 393 { NULL, NULL } 394 }; 395 396 #ifdef BLESSING 397 /* 398 * Pairs of locks which have been blessed 399 * Don't complain about order problems with blessed locks 400 */ 401 static struct witness_blessed blessed_list[] = { 402 }; 403 static int blessed_count = 404 sizeof(blessed_list) / sizeof(struct witness_blessed); 405 #endif 406 407 /* 408 * List of all locks in the system. 409 */ 410 TAILQ_HEAD(, lock_object) all_locks = TAILQ_HEAD_INITIALIZER(all_locks); 411 412 static struct mtx all_mtx = { 413 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 414 "All locks list", /* mtx_object.lo_name */ 415 "All locks list", /* mtx_object.lo_type */ 416 LO_INITIALIZED, /* mtx_object.lo_flags */ 417 { NULL, NULL }, /* mtx_object.lo_list */ 418 NULL }, /* mtx_object.lo_witness */ 419 MTX_UNOWNED, 0 /* mtx_lock, mtx_recurse */ 420 }; 421 422 /* 423 * This global is set to 0 once it becomes safe to use the witness code. 424 */ 425 static int witness_cold = 1; 426 427 /* 428 * Global variables for book keeping. 429 */ 430 static int lock_cur_cnt; 431 static int lock_max_cnt; 432 433 /* 434 * The WITNESS-enabled diagnostic code. 435 */ 436 static void 437 witness_initialize(void *dummy __unused) 438 { 439 struct lock_object *lock; 440 struct witness_order_list_entry *order; 441 struct witness *w, *w1; 442 int i; 443 444 /* 445 * We have to release Giant before initializing its witness 446 * structure so that WITNESS doesn't get confused. 447 */ 448 mtx_unlock(&Giant); 449 mtx_assert(&Giant, MA_NOTOWNED); 450 451 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 452 TAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 453 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 454 MTX_NOWITNESS); 455 for (i = 0; i < WITNESS_COUNT; i++) 456 witness_free(&w_data[i]); 457 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 458 witness_child_free(&w_childdata[i]); 459 for (i = 0; i < LOCK_CHILDCOUNT; i++) 460 witness_lock_list_free(&w_locklistdata[i]); 461 462 /* First add in all the specified order lists. */ 463 for (order = order_lists; order->w_name != NULL; order++) { 464 w = enroll(order->w_name, order->w_class); 465 if (w == NULL) 466 continue; 467 w->w_file = "order list"; 468 for (order++; order->w_name != NULL; order++) { 469 w1 = enroll(order->w_name, order->w_class); 470 if (w1 == NULL) 471 continue; 472 w1->w_file = "order list"; 473 if (!itismychild(w, w1)) 474 panic("Not enough memory for static orders!"); 475 w = w1; 476 } 477 } 478 479 /* Iterate through all locks and add them to witness. */ 480 mtx_lock(&all_mtx); 481 TAILQ_FOREACH(lock, &all_locks, lo_list) { 482 if (lock->lo_flags & LO_WITNESS) 483 lock->lo_witness = enroll(lock->lo_type, 484 lock->lo_class); 485 else 486 lock->lo_witness = NULL; 487 } 488 mtx_unlock(&all_mtx); 489 490 /* Mark the witness code as being ready for use. */ 491 atomic_store_rel_int(&witness_cold, 0); 492 493 mtx_lock(&Giant); 494 } 495 SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 496 497 static int 498 sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS) 499 { 500 int error, value; 501 502 value = witness_watch; 503 error = sysctl_handle_int(oidp, &value, 0, req); 504 if (error != 0 || req->newptr == NULL) 505 return (error); 506 error = suser(req->td); 507 if (error != 0) 508 return (error); 509 if (value == witness_watch) 510 return (0); 511 if (value != 0) 512 return (EINVAL); 513 witness_watch = 0; 514 return (0); 515 } 516 517 void 518 witness_init(struct lock_object *lock) 519 { 520 struct lock_class *class; 521 522 class = lock->lo_class; 523 if (lock->lo_flags & LO_INITIALIZED) 524 panic("%s: lock (%s) %s is already initialized", __func__, 525 class->lc_name, lock->lo_name); 526 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 527 (class->lc_flags & LC_RECURSABLE) == 0) 528 panic("%s: lock (%s) %s can not be recursable", __func__, 529 class->lc_name, lock->lo_name); 530 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 531 (class->lc_flags & LC_SLEEPABLE) == 0) 532 panic("%s: lock (%s) %s can not be sleepable", __func__, 533 class->lc_name, lock->lo_name); 534 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 535 (class->lc_flags & LC_UPGRADABLE) == 0) 536 panic("%s: lock (%s) %s can not be upgradable", __func__, 537 class->lc_name, lock->lo_name); 538 539 mtx_lock(&all_mtx); 540 TAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 541 lock->lo_flags |= LO_INITIALIZED; 542 lock_cur_cnt++; 543 if (lock_cur_cnt > lock_max_cnt) 544 lock_max_cnt = lock_cur_cnt; 545 mtx_unlock(&all_mtx); 546 if (!witness_cold && witness_watch != 0 && panicstr == NULL && 547 (lock->lo_flags & LO_WITNESS) != 0) 548 lock->lo_witness = enroll(lock->lo_type, class); 549 else 550 lock->lo_witness = NULL; 551 } 552 553 void 554 witness_destroy(struct lock_object *lock) 555 { 556 struct witness *w; 557 558 if (witness_cold) 559 panic("lock (%s) %s destroyed while witness_cold", 560 lock->lo_class->lc_name, lock->lo_name); 561 if ((lock->lo_flags & LO_INITIALIZED) == 0) 562 panic("%s: lock (%s) %s is not initialized", __func__, 563 lock->lo_class->lc_name, lock->lo_name); 564 565 /* XXX: need to verify that no one holds the lock */ 566 w = lock->lo_witness; 567 if (w != NULL) { 568 mtx_lock_spin(&w_mtx); 569 MPASS(w->w_refcount > 0); 570 w->w_refcount--; 571 572 /* 573 * Lock is already released if we have an allocation failure 574 * and depart() fails. 575 */ 576 if (w->w_refcount != 0 || depart(w)) 577 mtx_unlock_spin(&w_mtx); 578 } 579 580 mtx_lock(&all_mtx); 581 lock_cur_cnt--; 582 TAILQ_REMOVE(&all_locks, lock, lo_list); 583 lock->lo_flags &= ~LO_INITIALIZED; 584 mtx_unlock(&all_mtx); 585 } 586 587 #ifdef DDB 588 static void 589 witness_levelall (void) 590 { 591 struct witness_list *list; 592 struct witness *w, *w1; 593 594 /* 595 * First clear all levels. 596 */ 597 STAILQ_FOREACH(w, &w_all, w_list) { 598 w->w_level = 0; 599 } 600 601 /* 602 * Look for locks with no parent and level all their descendants. 603 */ 604 STAILQ_FOREACH(w, &w_all, w_list) { 605 /* 606 * This is just an optimization, technically we could get 607 * away just walking the all list each time. 608 */ 609 if (w->w_class->lc_flags & LC_SLEEPLOCK) 610 list = &w_sleep; 611 else 612 list = &w_spin; 613 STAILQ_FOREACH(w1, list, w_typelist) { 614 if (isitmychild(w1, w)) 615 goto skip; 616 } 617 witness_leveldescendents(w, 0); 618 skip: 619 ; /* silence GCC 3.x */ 620 } 621 } 622 623 static void 624 witness_leveldescendents(struct witness *parent, int level) 625 { 626 struct witness_child_list_entry *wcl; 627 int i; 628 629 if (parent->w_level < level) 630 parent->w_level = level; 631 level++; 632 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 633 for (i = 0; i < wcl->wcl_count; i++) 634 witness_leveldescendents(wcl->wcl_children[i], level); 635 } 636 637 static void 638 witness_displaydescendants(void(*prnt)(const char *fmt, ...), 639 struct witness *parent, int indent) 640 { 641 struct witness_child_list_entry *wcl; 642 int i, level; 643 644 level = parent->w_level; 645 prnt("%-2d", level); 646 for (i = 0; i < indent; i++) 647 prnt(" "); 648 if (parent->w_refcount > 0) 649 prnt("%s", parent->w_name); 650 else 651 prnt("(dead)"); 652 if (parent->w_displayed) { 653 prnt(" -- (already displayed)\n"); 654 return; 655 } 656 parent->w_displayed = 1; 657 if (parent->w_refcount > 0) { 658 if (parent->w_file != NULL) 659 prnt(" -- last acquired @ %s:%d", parent->w_file, 660 parent->w_line); 661 } 662 prnt("\n"); 663 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 664 for (i = 0; i < wcl->wcl_count; i++) 665 witness_displaydescendants(prnt, 666 wcl->wcl_children[i], indent + 1); 667 } 668 669 static void 670 witness_display_list(void(*prnt)(const char *fmt, ...), 671 struct witness_list *list) 672 { 673 struct witness *w; 674 675 STAILQ_FOREACH(w, list, w_typelist) { 676 if (w->w_file == NULL || w->w_level > 0) 677 continue; 678 /* 679 * This lock has no anscestors, display its descendants. 680 */ 681 witness_displaydescendants(prnt, w, 0); 682 } 683 } 684 685 static void 686 witness_display(void(*prnt)(const char *fmt, ...)) 687 { 688 struct witness *w; 689 690 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 691 witness_levelall(); 692 693 /* Clear all the displayed flags. */ 694 STAILQ_FOREACH(w, &w_all, w_list) { 695 w->w_displayed = 0; 696 } 697 698 /* 699 * First, handle sleep locks which have been acquired at least 700 * once. 701 */ 702 prnt("Sleep locks:\n"); 703 witness_display_list(prnt, &w_sleep); 704 705 /* 706 * Now do spin locks which have been acquired at least once. 707 */ 708 prnt("\nSpin locks:\n"); 709 witness_display_list(prnt, &w_spin); 710 711 /* 712 * Finally, any locks which have not been acquired yet. 713 */ 714 prnt("\nLocks which were never acquired:\n"); 715 STAILQ_FOREACH(w, &w_all, w_list) { 716 if (w->w_file != NULL || w->w_refcount == 0) 717 continue; 718 prnt("%s\n", w->w_name); 719 } 720 } 721 #endif /* DDB */ 722 723 /* Trim useless garbage from filenames. */ 724 static const char * 725 fixup_filename(const char *file) 726 { 727 728 if (file == NULL) 729 return (NULL); 730 while (strncmp(file, "../", 3) == 0) 731 file += 3; 732 return (file); 733 } 734 735 int 736 witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) 737 { 738 739 if (witness_watch == 0 || panicstr != NULL) 740 return (0); 741 742 /* Require locks that witness knows about. */ 743 if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || 744 lock2->lo_witness == NULL) 745 return (EINVAL); 746 747 MPASS(!mtx_owned(&w_mtx)); 748 mtx_lock_spin(&w_mtx); 749 750 /* 751 * If we already have either an explicit or implied lock order that 752 * is the other way around, then return an error. 753 */ 754 if (isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { 755 mtx_unlock_spin(&w_mtx); 756 return (EDOOFUS); 757 } 758 759 /* Try to add the new order. */ 760 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 761 lock2->lo_type, lock1->lo_type); 762 if (!itismychild(lock1->lo_witness, lock2->lo_witness)) 763 return (ENOMEM); 764 mtx_unlock_spin(&w_mtx); 765 return (0); 766 } 767 768 void 769 witness_checkorder(struct lock_object *lock, int flags, const char *file, 770 int line) 771 { 772 struct lock_list_entry **lock_list, *lle; 773 struct lock_instance *lock1, *lock2; 774 struct lock_class *class; 775 struct witness *w, *w1; 776 struct thread *td; 777 int i, j; 778 779 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 780 panicstr != NULL) 781 return; 782 783 /* 784 * Try locks do not block if they fail to acquire the lock, thus 785 * there is no danger of deadlocks or of switching while holding a 786 * spin lock if we acquire a lock via a try operation. This 787 * function shouldn't even be called for try locks, so panic if 788 * that happens. 789 */ 790 if (flags & LOP_TRYLOCK) 791 panic("%s should not be called for try lock operations", 792 __func__); 793 794 w = lock->lo_witness; 795 class = lock->lo_class; 796 td = curthread; 797 file = fixup_filename(file); 798 799 if (class->lc_flags & LC_SLEEPLOCK) { 800 /* 801 * Since spin locks include a critical section, this check 802 * implicitly enforces a lock order of all sleep locks before 803 * all spin locks. 804 */ 805 if (td->td_critnest != 0) 806 panic("blockable sleep lock (%s) %s @ %s:%d", 807 class->lc_name, lock->lo_name, file, line); 808 809 /* 810 * If this is the first lock acquired then just return as 811 * no order checking is needed. 812 */ 813 if (td->td_sleeplocks == NULL) 814 return; 815 lock_list = &td->td_sleeplocks; 816 } else { 817 /* 818 * If this is the first lock, just return as no order 819 * checking is needed. We check this in both if clauses 820 * here as unifying the check would require us to use a 821 * critical section to ensure we don't migrate while doing 822 * the check. Note that if this is not the first lock, we 823 * are already in a critical section and are safe for the 824 * rest of the check. 825 */ 826 if (PCPU_GET(spinlocks) == NULL) 827 return; 828 lock_list = PCPU_PTR(spinlocks); 829 } 830 831 /* 832 * Check to see if we are recursing on a lock we already own. If 833 * so, make sure that we don't mismatch exclusive and shared lock 834 * acquires. 835 */ 836 lock1 = find_instance(*lock_list, lock); 837 if (lock1 != NULL) { 838 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 839 (flags & LOP_EXCLUSIVE) == 0) { 840 printf("shared lock of (%s) %s @ %s:%d\n", 841 class->lc_name, lock->lo_name, file, line); 842 printf("while exclusively locked from %s:%d\n", 843 lock1->li_file, lock1->li_line); 844 panic("share->excl"); 845 } 846 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 847 (flags & LOP_EXCLUSIVE) != 0) { 848 printf("exclusive lock of (%s) %s @ %s:%d\n", 849 class->lc_name, lock->lo_name, file, line); 850 printf("while share locked from %s:%d\n", 851 lock1->li_file, lock1->li_line); 852 panic("excl->share"); 853 } 854 return; 855 } 856 857 /* 858 * Try locks do not block if they fail to acquire the lock, thus 859 * there is no danger of deadlocks or of switching while holding a 860 * spin lock if we acquire a lock via a try operation. 861 */ 862 if (flags & LOP_TRYLOCK) 863 return; 864 865 /* 866 * Check for duplicate locks of the same type. Note that we only 867 * have to check for this on the last lock we just acquired. Any 868 * other cases will be caught as lock order violations. 869 */ 870 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 871 w1 = lock1->li_lock->lo_witness; 872 if (w1 == w) { 873 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK)) 874 return; 875 w->w_same_squawked = 1; 876 printf("acquiring duplicate lock of same type: \"%s\"\n", 877 lock->lo_type); 878 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 879 lock1->li_file, lock1->li_line); 880 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 881 #ifdef KDB 882 goto debugger; 883 #else 884 return; 885 #endif 886 } 887 MPASS(!mtx_owned(&w_mtx)); 888 mtx_lock_spin(&w_mtx); 889 /* 890 * If we know that the the lock we are acquiring comes after 891 * the lock we most recently acquired in the lock order tree, 892 * then there is no need for any further checks. 893 */ 894 if (isitmychild(w1, w)) { 895 mtx_unlock_spin(&w_mtx); 896 return; 897 } 898 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 899 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 900 901 MPASS(j < WITNESS_COUNT); 902 lock1 = &lle->ll_children[i]; 903 w1 = lock1->li_lock->lo_witness; 904 905 /* 906 * If this lock doesn't undergo witness checking, 907 * then skip it. 908 */ 909 if (w1 == NULL) { 910 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 911 ("lock missing witness structure")); 912 continue; 913 } 914 /* 915 * If we are locking Giant and this is a sleepable 916 * lock, then skip it. 917 */ 918 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && 919 lock == &Giant.mtx_object) 920 continue; 921 /* 922 * If we are locking a sleepable lock and this lock 923 * is Giant, then skip it. 924 */ 925 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 926 lock1->li_lock == &Giant.mtx_object) 927 continue; 928 /* 929 * If we are locking a sleepable lock and this lock 930 * isn't sleepable, we want to treat it as a lock 931 * order violation to enfore a general lock order of 932 * sleepable locks before non-sleepable locks. 933 */ 934 if (!((lock->lo_flags & LO_SLEEPABLE) != 0 && 935 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 936 /* 937 * Check the lock order hierarchy for a reveresal. 938 */ 939 if (!isitmydescendant(w, w1)) 940 continue; 941 /* 942 * We have a lock order violation, check to see if it 943 * is allowed or has already been yelled about. 944 */ 945 mtx_unlock_spin(&w_mtx); 946 #ifdef BLESSING 947 /* 948 * If the lock order is blessed, just bail. We don't 949 * look for other lock order violations though, which 950 * may be a bug. 951 */ 952 if (blessed(w, w1)) 953 return; 954 #endif 955 if (lock1->li_lock == &Giant.mtx_object) { 956 if (w1->w_Giant_squawked) 957 return; 958 else 959 w1->w_Giant_squawked = 1; 960 } else { 961 if (w1->w_other_squawked) 962 return; 963 else 964 w1->w_other_squawked = 1; 965 } 966 /* 967 * Ok, yell about it. 968 */ 969 printf("lock order reversal\n"); 970 /* 971 * Try to locate an earlier lock with 972 * witness w in our list. 973 */ 974 do { 975 lock2 = &lle->ll_children[i]; 976 MPASS(lock2->li_lock != NULL); 977 if (lock2->li_lock->lo_witness == w) 978 break; 979 if (i == 0 && lle->ll_next != NULL) { 980 lle = lle->ll_next; 981 i = lle->ll_count - 1; 982 MPASS(i >= 0 && i < LOCK_NCHILDREN); 983 } else 984 i--; 985 } while (i >= 0); 986 if (i < 0) { 987 printf(" 1st %p %s (%s) @ %s:%d\n", 988 lock1->li_lock, lock1->li_lock->lo_name, 989 lock1->li_lock->lo_type, lock1->li_file, 990 lock1->li_line); 991 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 992 lock->lo_name, lock->lo_type, file, line); 993 } else { 994 printf(" 1st %p %s (%s) @ %s:%d\n", 995 lock2->li_lock, lock2->li_lock->lo_name, 996 lock2->li_lock->lo_type, lock2->li_file, 997 lock2->li_line); 998 printf(" 2nd %p %s (%s) @ %s:%d\n", 999 lock1->li_lock, lock1->li_lock->lo_name, 1000 lock1->li_lock->lo_type, lock1->li_file, 1001 lock1->li_line); 1002 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 1003 lock->lo_name, lock->lo_type, file, line); 1004 } 1005 #ifdef KDB 1006 goto debugger; 1007 #else 1008 return; 1009 #endif 1010 } 1011 } 1012 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 1013 /* 1014 * If requested, build a new lock order. However, don't build a new 1015 * relationship between a sleepable lock and Giant if it is in the 1016 * wrong direction. The correct lock order is that sleepable locks 1017 * always come before Giant. 1018 */ 1019 if (flags & LOP_NEWORDER && 1020 !(lock1->li_lock == &Giant.mtx_object && 1021 (lock->lo_flags & LO_SLEEPABLE) != 0)) { 1022 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 1023 lock->lo_type, lock1->li_lock->lo_type); 1024 if (!itismychild(lock1->li_lock->lo_witness, w)) 1025 /* Witness is dead. */ 1026 return; 1027 } 1028 mtx_unlock_spin(&w_mtx); 1029 return; 1030 1031 #ifdef KDB 1032 debugger: 1033 if (witness_trace) 1034 kdb_backtrace(); 1035 if (witness_kdb) 1036 kdb_enter(__func__); 1037 #endif 1038 } 1039 1040 void 1041 witness_lock(struct lock_object *lock, int flags, const char *file, int line) 1042 { 1043 struct lock_list_entry **lock_list, *lle; 1044 struct lock_instance *instance; 1045 struct witness *w; 1046 struct thread *td; 1047 1048 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1049 panicstr != NULL) 1050 return; 1051 w = lock->lo_witness; 1052 td = curthread; 1053 file = fixup_filename(file); 1054 1055 /* Determine lock list for this lock. */ 1056 if (lock->lo_class->lc_flags & LC_SLEEPLOCK) 1057 lock_list = &td->td_sleeplocks; 1058 else 1059 lock_list = PCPU_PTR(spinlocks); 1060 1061 /* Check to see if we are recursing on a lock we already own. */ 1062 instance = find_instance(*lock_list, lock); 1063 if (instance != NULL) { 1064 instance->li_flags++; 1065 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 1066 td->td_proc->p_pid, lock->lo_name, 1067 instance->li_flags & LI_RECURSEMASK); 1068 instance->li_file = file; 1069 instance->li_line = line; 1070 return; 1071 } 1072 1073 /* Update per-witness last file and line acquire. */ 1074 w->w_file = file; 1075 w->w_line = line; 1076 1077 /* Find the next open lock instance in the list and fill it. */ 1078 lle = *lock_list; 1079 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 1080 lle = witness_lock_list_get(); 1081 if (lle == NULL) 1082 return; 1083 lle->ll_next = *lock_list; 1084 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 1085 td->td_proc->p_pid, lle); 1086 *lock_list = lle; 1087 } 1088 instance = &lle->ll_children[lle->ll_count++]; 1089 instance->li_lock = lock; 1090 instance->li_line = line; 1091 instance->li_file = file; 1092 if ((flags & LOP_EXCLUSIVE) != 0) 1093 instance->li_flags = LI_EXCLUSIVE; 1094 else 1095 instance->li_flags = 0; 1096 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 1097 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 1098 } 1099 1100 void 1101 witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 1102 { 1103 struct lock_instance *instance; 1104 struct lock_class *class; 1105 1106 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1107 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1108 return; 1109 class = lock->lo_class; 1110 file = fixup_filename(file); 1111 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1112 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 1113 class->lc_name, lock->lo_name, file, line); 1114 if ((flags & LOP_TRYLOCK) == 0) 1115 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 1116 lock->lo_name, file, line); 1117 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1118 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 1119 class->lc_name, lock->lo_name, file, line); 1120 instance = find_instance(curthread->td_sleeplocks, lock); 1121 if (instance == NULL) 1122 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 1123 class->lc_name, lock->lo_name, file, line); 1124 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 1125 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 1126 class->lc_name, lock->lo_name, file, line); 1127 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1128 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 1129 class->lc_name, lock->lo_name, 1130 instance->li_flags & LI_RECURSEMASK, file, line); 1131 instance->li_flags |= LI_EXCLUSIVE; 1132 } 1133 1134 void 1135 witness_downgrade(struct lock_object *lock, int flags, const char *file, 1136 int line) 1137 { 1138 struct lock_instance *instance; 1139 struct lock_class *class; 1140 1141 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1142 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1143 return; 1144 class = lock->lo_class; 1145 file = fixup_filename(file); 1146 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1147 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 1148 class->lc_name, lock->lo_name, file, line); 1149 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1150 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 1151 class->lc_name, lock->lo_name, file, line); 1152 instance = find_instance(curthread->td_sleeplocks, lock); 1153 if (instance == NULL) 1154 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 1155 class->lc_name, lock->lo_name, file, line); 1156 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 1157 panic("downgrade of shared lock (%s) %s @ %s:%d", 1158 class->lc_name, lock->lo_name, file, line); 1159 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1160 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 1161 class->lc_name, lock->lo_name, 1162 instance->li_flags & LI_RECURSEMASK, file, line); 1163 instance->li_flags &= ~LI_EXCLUSIVE; 1164 } 1165 1166 void 1167 witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 1168 { 1169 struct lock_list_entry **lock_list, *lle; 1170 struct lock_instance *instance; 1171 struct lock_class *class; 1172 struct thread *td; 1173 register_t s; 1174 int i, j; 1175 1176 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1177 panicstr != NULL) 1178 return; 1179 td = curthread; 1180 class = lock->lo_class; 1181 file = fixup_filename(file); 1182 1183 /* Find lock instance associated with this lock. */ 1184 if (class->lc_flags & LC_SLEEPLOCK) 1185 lock_list = &td->td_sleeplocks; 1186 else 1187 lock_list = PCPU_PTR(spinlocks); 1188 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 1189 for (i = 0; i < (*lock_list)->ll_count; i++) { 1190 instance = &(*lock_list)->ll_children[i]; 1191 if (instance->li_lock == lock) 1192 goto found; 1193 } 1194 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 1195 file, line); 1196 found: 1197 1198 /* First, check for shared/exclusive mismatches. */ 1199 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 1200 (flags & LOP_EXCLUSIVE) == 0) { 1201 printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name, 1202 lock->lo_name, file, line); 1203 printf("while exclusively locked from %s:%d\n", 1204 instance->li_file, instance->li_line); 1205 panic("excl->ushare"); 1206 } 1207 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 1208 (flags & LOP_EXCLUSIVE) != 0) { 1209 printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name, 1210 lock->lo_name, file, line); 1211 printf("while share locked from %s:%d\n", instance->li_file, 1212 instance->li_line); 1213 panic("share->uexcl"); 1214 } 1215 1216 /* If we are recursed, unrecurse. */ 1217 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 1218 CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, 1219 td->td_proc->p_pid, instance->li_lock->lo_name, 1220 instance->li_flags); 1221 instance->li_flags--; 1222 return; 1223 } 1224 1225 /* Otherwise, remove this item from the list. */ 1226 s = intr_disable(); 1227 CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, 1228 td->td_proc->p_pid, instance->li_lock->lo_name, 1229 (*lock_list)->ll_count - 1); 1230 for (j = i; j < (*lock_list)->ll_count - 1; j++) 1231 (*lock_list)->ll_children[j] = 1232 (*lock_list)->ll_children[j + 1]; 1233 (*lock_list)->ll_count--; 1234 intr_restore(s); 1235 1236 /* If this lock list entry is now empty, free it. */ 1237 if ((*lock_list)->ll_count == 0) { 1238 lle = *lock_list; 1239 *lock_list = lle->ll_next; 1240 CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, 1241 td->td_proc->p_pid, lle); 1242 witness_lock_list_free(lle); 1243 } 1244 } 1245 1246 /* 1247 * Warn if any locks other than 'lock' are held. Flags can be passed in to 1248 * exempt Giant and sleepable locks from the checks as well. If any 1249 * non-exempt locks are held, then a supplied message is printed to the 1250 * console along with a list of the offending locks. If indicated in the 1251 * flags then a failure results in a panic as well. 1252 */ 1253 int 1254 witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) 1255 { 1256 struct lock_list_entry *lle; 1257 struct lock_instance *lock1; 1258 struct thread *td; 1259 va_list ap; 1260 int i, n; 1261 1262 if (witness_cold || witness_watch == 0 || panicstr != NULL) 1263 return (0); 1264 n = 0; 1265 td = curthread; 1266 for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next) 1267 for (i = lle->ll_count - 1; i >= 0; i--) { 1268 lock1 = &lle->ll_children[i]; 1269 if (lock1->li_lock == lock) 1270 continue; 1271 if (flags & WARN_GIANTOK && 1272 lock1->li_lock == &Giant.mtx_object) 1273 continue; 1274 if (flags & WARN_SLEEPOK && 1275 (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) 1276 continue; 1277 if (n == 0) { 1278 va_start(ap, fmt); 1279 vprintf(fmt, ap); 1280 va_end(ap); 1281 printf(" with the following"); 1282 if (flags & WARN_SLEEPOK) 1283 printf(" non-sleepable"); 1284 printf(" locks held:\n"); 1285 } 1286 n++; 1287 witness_list_lock(lock1); 1288 } 1289 if (PCPU_GET(spinlocks) != NULL) { 1290 /* 1291 * Since we already hold a spinlock preemption is 1292 * already blocked. 1293 */ 1294 if (n == 0) { 1295 va_start(ap, fmt); 1296 vprintf(fmt, ap); 1297 va_end(ap); 1298 printf(" with the following"); 1299 if (flags & WARN_SLEEPOK) 1300 printf(" non-sleepable"); 1301 printf(" locks held:\n"); 1302 } 1303 n += witness_list_locks(PCPU_PTR(spinlocks)); 1304 } 1305 if (flags & WARN_PANIC && n) 1306 panic("witness_warn"); 1307 #ifdef KDB 1308 else if (witness_kdb && n) 1309 kdb_enter(__func__); 1310 else if (witness_trace && n) 1311 kdb_backtrace(); 1312 #endif 1313 return (n); 1314 } 1315 1316 const char * 1317 witness_file(struct lock_object *lock) 1318 { 1319 struct witness *w; 1320 1321 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1322 return ("?"); 1323 w = lock->lo_witness; 1324 return (w->w_file); 1325 } 1326 1327 int 1328 witness_line(struct lock_object *lock) 1329 { 1330 struct witness *w; 1331 1332 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1333 return (0); 1334 w = lock->lo_witness; 1335 return (w->w_line); 1336 } 1337 1338 static struct witness * 1339 enroll(const char *description, struct lock_class *lock_class) 1340 { 1341 struct witness *w; 1342 1343 if (witness_watch == 0 || panicstr != NULL) 1344 return (NULL); 1345 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 1346 return (NULL); 1347 mtx_lock_spin(&w_mtx); 1348 STAILQ_FOREACH(w, &w_all, w_list) { 1349 if (w->w_name == description || (w->w_refcount > 0 && 1350 strcmp(description, w->w_name) == 0)) { 1351 w->w_refcount++; 1352 mtx_unlock_spin(&w_mtx); 1353 if (lock_class != w->w_class) 1354 panic( 1355 "lock (%s) %s does not match earlier (%s) lock", 1356 description, lock_class->lc_name, 1357 w->w_class->lc_name); 1358 return (w); 1359 } 1360 } 1361 /* 1362 * This isn't quite right, as witness_cold is still 0 while we 1363 * enroll all the locks initialized before witness_initialize(). 1364 */ 1365 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 1366 mtx_unlock_spin(&w_mtx); 1367 panic("spin lock %s not in order list", description); 1368 } 1369 if ((w = witness_get()) == NULL) 1370 return (NULL); 1371 w->w_name = description; 1372 w->w_class = lock_class; 1373 w->w_refcount = 1; 1374 STAILQ_INSERT_HEAD(&w_all, w, w_list); 1375 if (lock_class->lc_flags & LC_SPINLOCK) { 1376 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 1377 w_spin_cnt++; 1378 } else if (lock_class->lc_flags & LC_SLEEPLOCK) { 1379 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 1380 w_sleep_cnt++; 1381 } else { 1382 mtx_unlock_spin(&w_mtx); 1383 panic("lock class %s is not sleep or spin", 1384 lock_class->lc_name); 1385 } 1386 mtx_unlock_spin(&w_mtx); 1387 return (w); 1388 } 1389 1390 /* Don't let the door bang you on the way out... */ 1391 static int 1392 depart(struct witness *w) 1393 { 1394 struct witness_child_list_entry *wcl, *nwcl; 1395 struct witness_list *list; 1396 struct witness *parent; 1397 1398 MPASS(w->w_refcount == 0); 1399 if (w->w_class->lc_flags & LC_SLEEPLOCK) { 1400 list = &w_sleep; 1401 w_sleep_cnt--; 1402 } else { 1403 list = &w_spin; 1404 w_spin_cnt--; 1405 } 1406 /* 1407 * First, we run through the entire tree looking for any 1408 * witnesses that the outgoing witness is a child of. For 1409 * each parent that we find, we reparent all the direct 1410 * children of the outgoing witness to its parent. 1411 */ 1412 STAILQ_FOREACH(parent, list, w_typelist) { 1413 if (!isitmychild(parent, w)) 1414 continue; 1415 removechild(parent, w); 1416 } 1417 1418 /* 1419 * Now we go through and free up the child list of the 1420 * outgoing witness. 1421 */ 1422 for (wcl = w->w_children; wcl != NULL; wcl = nwcl) { 1423 nwcl = wcl->wcl_next; 1424 w_child_cnt--; 1425 witness_child_free(wcl); 1426 } 1427 1428 /* 1429 * Detach from various lists and free. 1430 */ 1431 STAILQ_REMOVE(list, w, witness, w_typelist); 1432 STAILQ_REMOVE(&w_all, w, witness, w_list); 1433 witness_free(w); 1434 1435 return (1); 1436 } 1437 1438 /* 1439 * Add "child" as a direct child of "parent". Returns false if 1440 * we fail due to out of memory. 1441 */ 1442 static int 1443 insertchild(struct witness *parent, struct witness *child) 1444 { 1445 struct witness_child_list_entry **wcl; 1446 1447 MPASS(child != NULL && parent != NULL); 1448 1449 /* 1450 * Insert "child" after "parent" 1451 */ 1452 wcl = &parent->w_children; 1453 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1454 wcl = &(*wcl)->wcl_next; 1455 if (*wcl == NULL) { 1456 *wcl = witness_child_get(); 1457 if (*wcl == NULL) 1458 return (0); 1459 w_child_cnt++; 1460 } 1461 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1462 1463 return (1); 1464 } 1465 1466 1467 static int 1468 itismychild(struct witness *parent, struct witness *child) 1469 { 1470 struct witness_list *list; 1471 1472 MPASS(child != NULL && parent != NULL); 1473 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 1474 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 1475 panic( 1476 "%s: parent (%s) and child (%s) are not the same lock type", 1477 __func__, parent->w_class->lc_name, 1478 child->w_class->lc_name); 1479 1480 if (!insertchild(parent, child)) 1481 return (0); 1482 1483 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1484 list = &w_sleep; 1485 else 1486 list = &w_spin; 1487 return (1); 1488 } 1489 1490 static void 1491 removechild(struct witness *parent, struct witness *child) 1492 { 1493 struct witness_child_list_entry **wcl, *wcl1; 1494 int i; 1495 1496 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1497 for (i = 0; i < (*wcl)->wcl_count; i++) 1498 if ((*wcl)->wcl_children[i] == child) 1499 goto found; 1500 return; 1501 found: 1502 (*wcl)->wcl_count--; 1503 if ((*wcl)->wcl_count > i) 1504 (*wcl)->wcl_children[i] = 1505 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1506 MPASS((*wcl)->wcl_children[i] != NULL); 1507 if ((*wcl)->wcl_count != 0) 1508 return; 1509 wcl1 = *wcl; 1510 *wcl = wcl1->wcl_next; 1511 w_child_cnt--; 1512 witness_child_free(wcl1); 1513 } 1514 1515 static int 1516 isitmychild(struct witness *parent, struct witness *child) 1517 { 1518 struct witness_child_list_entry *wcl; 1519 int i; 1520 1521 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1522 for (i = 0; i < wcl->wcl_count; i++) { 1523 if (wcl->wcl_children[i] == child) 1524 return (1); 1525 } 1526 } 1527 return (0); 1528 } 1529 1530 static int 1531 isitmydescendant(struct witness *parent, struct witness *child) 1532 { 1533 struct witness_child_list_entry *wcl; 1534 int i, j; 1535 1536 if (isitmychild(parent, child)) 1537 return (1); 1538 j = 0; 1539 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1540 MPASS(j < 1000); 1541 for (i = 0; i < wcl->wcl_count; i++) { 1542 if (isitmydescendant(wcl->wcl_children[i], child)) 1543 return (1); 1544 } 1545 j++; 1546 } 1547 return (0); 1548 } 1549 1550 #ifdef BLESSING 1551 static int 1552 blessed(struct witness *w1, struct witness *w2) 1553 { 1554 int i; 1555 struct witness_blessed *b; 1556 1557 for (i = 0; i < blessed_count; i++) { 1558 b = &blessed_list[i]; 1559 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1560 if (strcmp(w2->w_name, b->b_lock2) == 0) 1561 return (1); 1562 continue; 1563 } 1564 if (strcmp(w1->w_name, b->b_lock2) == 0) 1565 if (strcmp(w2->w_name, b->b_lock1) == 0) 1566 return (1); 1567 } 1568 return (0); 1569 } 1570 #endif 1571 1572 static struct witness * 1573 witness_get(void) 1574 { 1575 struct witness *w; 1576 1577 if (witness_watch == 0) { 1578 mtx_unlock_spin(&w_mtx); 1579 return (NULL); 1580 } 1581 if (STAILQ_EMPTY(&w_free)) { 1582 witness_watch = 0; 1583 mtx_unlock_spin(&w_mtx); 1584 printf("%s: witness exhausted\n", __func__); 1585 return (NULL); 1586 } 1587 w = STAILQ_FIRST(&w_free); 1588 STAILQ_REMOVE_HEAD(&w_free, w_list); 1589 w_free_cnt--; 1590 bzero(w, sizeof(*w)); 1591 return (w); 1592 } 1593 1594 static void 1595 witness_free(struct witness *w) 1596 { 1597 1598 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1599 w_free_cnt++; 1600 } 1601 1602 static struct witness_child_list_entry * 1603 witness_child_get(void) 1604 { 1605 struct witness_child_list_entry *wcl; 1606 1607 if (witness_watch == 0) { 1608 mtx_unlock_spin(&w_mtx); 1609 return (NULL); 1610 } 1611 wcl = w_child_free; 1612 if (wcl == NULL) { 1613 witness_watch = 0; 1614 mtx_unlock_spin(&w_mtx); 1615 printf("%s: witness exhausted\n", __func__); 1616 return (NULL); 1617 } 1618 w_child_free = wcl->wcl_next; 1619 w_child_free_cnt--; 1620 bzero(wcl, sizeof(*wcl)); 1621 return (wcl); 1622 } 1623 1624 static void 1625 witness_child_free(struct witness_child_list_entry *wcl) 1626 { 1627 1628 wcl->wcl_next = w_child_free; 1629 w_child_free = wcl; 1630 w_child_free_cnt++; 1631 } 1632 1633 static struct lock_list_entry * 1634 witness_lock_list_get(void) 1635 { 1636 struct lock_list_entry *lle; 1637 1638 if (witness_watch == 0) 1639 return (NULL); 1640 mtx_lock_spin(&w_mtx); 1641 lle = w_lock_list_free; 1642 if (lle == NULL) { 1643 witness_watch = 0; 1644 mtx_unlock_spin(&w_mtx); 1645 printf("%s: witness exhausted\n", __func__); 1646 return (NULL); 1647 } 1648 w_lock_list_free = lle->ll_next; 1649 mtx_unlock_spin(&w_mtx); 1650 bzero(lle, sizeof(*lle)); 1651 return (lle); 1652 } 1653 1654 static void 1655 witness_lock_list_free(struct lock_list_entry *lle) 1656 { 1657 1658 mtx_lock_spin(&w_mtx); 1659 lle->ll_next = w_lock_list_free; 1660 w_lock_list_free = lle; 1661 mtx_unlock_spin(&w_mtx); 1662 } 1663 1664 static struct lock_instance * 1665 find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1666 { 1667 struct lock_list_entry *lle; 1668 struct lock_instance *instance; 1669 int i; 1670 1671 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1672 for (i = lle->ll_count - 1; i >= 0; i--) { 1673 instance = &lle->ll_children[i]; 1674 if (instance->li_lock == lock) 1675 return (instance); 1676 } 1677 return (NULL); 1678 } 1679 1680 static void 1681 witness_list_lock(struct lock_instance *instance) 1682 { 1683 struct lock_object *lock; 1684 1685 lock = instance->li_lock; 1686 printf("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1687 "exclusive" : "shared", lock->lo_class->lc_name, lock->lo_name); 1688 if (lock->lo_type != lock->lo_name) 1689 printf(" (%s)", lock->lo_type); 1690 printf(" r = %d (%p) locked @ %s:%d\n", 1691 instance->li_flags & LI_RECURSEMASK, lock, instance->li_file, 1692 instance->li_line); 1693 } 1694 1695 #ifdef DDB 1696 static int 1697 witness_thread_has_locks(struct thread *td) 1698 { 1699 1700 return (td->td_sleeplocks != NULL); 1701 } 1702 1703 static int 1704 witness_proc_has_locks(struct proc *p) 1705 { 1706 struct thread *td; 1707 1708 FOREACH_THREAD_IN_PROC(p, td) { 1709 if (witness_thread_has_locks(td)) 1710 return (1); 1711 } 1712 return (0); 1713 } 1714 #endif 1715 1716 int 1717 witness_list_locks(struct lock_list_entry **lock_list) 1718 { 1719 struct lock_list_entry *lle; 1720 int i, nheld; 1721 1722 nheld = 0; 1723 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1724 for (i = lle->ll_count - 1; i >= 0; i--) { 1725 witness_list_lock(&lle->ll_children[i]); 1726 nheld++; 1727 } 1728 return (nheld); 1729 } 1730 1731 /* 1732 * This is a bit risky at best. We call this function when we have timed 1733 * out acquiring a spin lock, and we assume that the other CPU is stuck 1734 * with this lock held. So, we go groveling around in the other CPU's 1735 * per-cpu data to try to find the lock instance for this spin lock to 1736 * see when it was last acquired. 1737 */ 1738 void 1739 witness_display_spinlock(struct lock_object *lock, struct thread *owner) 1740 { 1741 struct lock_instance *instance; 1742 struct pcpu *pc; 1743 1744 if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU) 1745 return; 1746 pc = pcpu_find(owner->td_oncpu); 1747 instance = find_instance(pc->pc_spinlocks, lock); 1748 if (instance != NULL) 1749 witness_list_lock(instance); 1750 } 1751 1752 void 1753 witness_save(struct lock_object *lock, const char **filep, int *linep) 1754 { 1755 struct lock_instance *instance; 1756 1757 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1758 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1759 return; 1760 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1761 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1762 lock->lo_class->lc_name, lock->lo_name); 1763 instance = find_instance(curthread->td_sleeplocks, lock); 1764 if (instance == NULL) 1765 panic("%s: lock (%s) %s not locked", __func__, 1766 lock->lo_class->lc_name, lock->lo_name); 1767 *filep = instance->li_file; 1768 *linep = instance->li_line; 1769 } 1770 1771 void 1772 witness_restore(struct lock_object *lock, const char *file, int line) 1773 { 1774 struct lock_instance *instance; 1775 1776 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1777 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1778 return; 1779 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1780 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1781 lock->lo_class->lc_name, lock->lo_name); 1782 instance = find_instance(curthread->td_sleeplocks, lock); 1783 if (instance == NULL) 1784 panic("%s: lock (%s) %s not locked", __func__, 1785 lock->lo_class->lc_name, lock->lo_name); 1786 lock->lo_witness->w_file = file; 1787 lock->lo_witness->w_line = line; 1788 instance->li_file = file; 1789 instance->li_line = line; 1790 } 1791 1792 void 1793 witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1794 { 1795 #ifdef INVARIANT_SUPPORT 1796 struct lock_instance *instance; 1797 1798 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1799 return; 1800 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1801 instance = find_instance(curthread->td_sleeplocks, lock); 1802 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1803 instance = find_instance(PCPU_GET(spinlocks), lock); 1804 else { 1805 panic("Lock (%s) %s is not sleep or spin!", 1806 lock->lo_class->lc_name, lock->lo_name); 1807 } 1808 file = fixup_filename(file); 1809 switch (flags) { 1810 case LA_UNLOCKED: 1811 if (instance != NULL) 1812 panic("Lock (%s) %s locked @ %s:%d.", 1813 lock->lo_class->lc_name, lock->lo_name, file, line); 1814 break; 1815 case LA_LOCKED: 1816 case LA_LOCKED | LA_RECURSED: 1817 case LA_LOCKED | LA_NOTRECURSED: 1818 case LA_SLOCKED: 1819 case LA_SLOCKED | LA_RECURSED: 1820 case LA_SLOCKED | LA_NOTRECURSED: 1821 case LA_XLOCKED: 1822 case LA_XLOCKED | LA_RECURSED: 1823 case LA_XLOCKED | LA_NOTRECURSED: 1824 if (instance == NULL) { 1825 panic("Lock (%s) %s not locked @ %s:%d.", 1826 lock->lo_class->lc_name, lock->lo_name, file, line); 1827 break; 1828 } 1829 if ((flags & LA_XLOCKED) != 0 && 1830 (instance->li_flags & LI_EXCLUSIVE) == 0) 1831 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1832 lock->lo_class->lc_name, lock->lo_name, file, line); 1833 if ((flags & LA_SLOCKED) != 0 && 1834 (instance->li_flags & LI_EXCLUSIVE) != 0) 1835 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1836 lock->lo_class->lc_name, lock->lo_name, file, line); 1837 if ((flags & LA_RECURSED) != 0 && 1838 (instance->li_flags & LI_RECURSEMASK) == 0) 1839 panic("Lock (%s) %s not recursed @ %s:%d.", 1840 lock->lo_class->lc_name, lock->lo_name, file, line); 1841 if ((flags & LA_NOTRECURSED) != 0 && 1842 (instance->li_flags & LI_RECURSEMASK) != 0) 1843 panic("Lock (%s) %s recursed @ %s:%d.", 1844 lock->lo_class->lc_name, lock->lo_name, file, line); 1845 break; 1846 default: 1847 panic("Invalid lock assertion at %s:%d.", file, line); 1848 1849 } 1850 #endif /* INVARIANT_SUPPORT */ 1851 } 1852 1853 #ifdef DDB 1854 static void 1855 witness_list(struct thread *td) 1856 { 1857 1858 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1859 KASSERT(kdb_active, ("%s: not in the debugger", __func__)); 1860 1861 if (witness_watch == 0) 1862 return; 1863 1864 witness_list_locks(&td->td_sleeplocks); 1865 1866 /* 1867 * We only handle spinlocks if td == curthread. This is somewhat broken 1868 * if td is currently executing on some other CPU and holds spin locks 1869 * as we won't display those locks. If we had a MI way of getting 1870 * the per-cpu data for a given cpu then we could use 1871 * td->td_oncpu to get the list of spinlocks for this thread 1872 * and "fix" this. 1873 * 1874 * That still wouldn't really fix this unless we locked sched_lock 1875 * or stopped the other CPU to make sure it wasn't changing the list 1876 * out from under us. It is probably best to just not try to handle 1877 * threads on other CPU's for now. 1878 */ 1879 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1880 witness_list_locks(PCPU_PTR(spinlocks)); 1881 } 1882 1883 DB_SHOW_COMMAND(locks, db_witness_list) 1884 { 1885 struct thread *td; 1886 pid_t pid; 1887 struct proc *p; 1888 1889 if (have_addr) { 1890 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1891 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1892 ((addr >> 16) % 16) * 10000; 1893 /* sx_slock(&allproc_lock); */ 1894 FOREACH_PROC_IN_SYSTEM(p) { 1895 if (p->p_pid == pid) 1896 break; 1897 } 1898 /* sx_sunlock(&allproc_lock); */ 1899 if (p == NULL) { 1900 db_printf("pid %d not found\n", pid); 1901 return; 1902 } 1903 FOREACH_THREAD_IN_PROC(p, td) { 1904 witness_list(td); 1905 } 1906 } else { 1907 td = curthread; 1908 witness_list(td); 1909 } 1910 } 1911 1912 DB_SHOW_COMMAND(alllocks, db_witness_list_all) 1913 { 1914 struct thread *td; 1915 struct proc *p; 1916 1917 /* 1918 * It would be nice to list only threads and processes that actually 1919 * held sleep locks, but that information is currently not exported 1920 * by WITNESS. 1921 */ 1922 FOREACH_PROC_IN_SYSTEM(p) { 1923 if (!witness_proc_has_locks(p)) 1924 continue; 1925 FOREACH_THREAD_IN_PROC(p, td) { 1926 if (!witness_thread_has_locks(td)) 1927 continue; 1928 printf("Process %d (%s) thread %p (%d)\n", p->p_pid, 1929 p->p_comm, td, td->td_tid); 1930 witness_list(td); 1931 } 1932 } 1933 } 1934 1935 DB_SHOW_COMMAND(witness, db_witness_display) 1936 { 1937 1938 witness_display(db_printf); 1939 } 1940 #endif
Cache object: ad7bbddad5462514c8616f9d2c4719c3
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