subr_witness.c revision 148896
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: head/sys/kern/subr_witness.c 148896 2005-08-09 13:27:50Z rwatson $"); 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 1024 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 120struct witness_child_list_entry; 121 122struct 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 138struct 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 144STAILQ_HEAD(witness_list, witness); 145 146#ifdef BLESSING 147struct witness_blessed { 148 const char *b_lock1; 149 const char *b_lock2; 150}; 151#endif 152 153struct witness_order_list_entry { 154 const char *w_name; 155 struct lock_class *w_class; 156}; 157 158#ifdef BLESSING 159static int blessed(struct witness *, struct witness *); 160#endif 161static int depart(struct witness *w); 162static struct witness *enroll(const char *description, 163 struct lock_class *lock_class); 164static int insertchild(struct witness *parent, struct witness *child); 165static int isitmychild(struct witness *parent, struct witness *child); 166static int isitmydescendant(struct witness *parent, struct witness *child); 167static int itismychild(struct witness *parent, struct witness *child); 168static int rebalancetree(struct witness_list *list); 169static void removechild(struct witness *parent, struct witness *child); 170static int reparentchildren(struct witness *newparent, 171 struct witness *oldparent); 172static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS); 173static void witness_displaydescendants(void(*)(const char *fmt, ...), 174 struct witness *, int indent); 175static const char *fixup_filename(const char *file); 176static void witness_leveldescendents(struct witness *parent, int level); 177static void witness_levelall(void); 178static struct witness *witness_get(void); 179static void witness_free(struct witness *m); 180static struct witness_child_list_entry *witness_child_get(void); 181static void witness_child_free(struct witness_child_list_entry *wcl); 182static struct lock_list_entry *witness_lock_list_get(void); 183static void witness_lock_list_free(struct lock_list_entry *lle); 184static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 185 struct lock_object *lock); 186static void witness_list_lock(struct lock_instance *instance); 187#ifdef DDB 188static void witness_list(struct thread *td); 189static void witness_display_list(void(*prnt)(const char *fmt, ...), 190 struct witness_list *list); 191static void witness_display(void(*)(const char *fmt, ...)); 192#endif 193 194SYSCTL_NODE(_debug, OID_AUTO, witness, CTLFLAG_RW, 0, "Witness Locking"); 195 196/* 197 * If set to 0, witness is disabled. If set to 1, witness performs full lock 198 * order checking for all locks. If set to 2 or higher, then witness skips 199 * the full lock order check if the lock being acquired is at a higher level 200 * (i.e. farther down in the tree) than the current lock. This last mode is 201 * somewhat experimental and not considered fully safe. At runtime, this 202 * value may be set to 0 to turn off witness. witness is not allowed be 203 * turned on once it is turned off, however. 204 */ 205static int witness_watch = 1; 206TUNABLE_INT("debug.witness.watch", &witness_watch); 207SYSCTL_PROC(_debug_witness, OID_AUTO, watch, CTLFLAG_RW | CTLTYPE_INT, NULL, 0, 208 sysctl_debug_witness_watch, "I", "witness is watching lock operations"); 209 210#ifdef KDB 211/* 212 * When KDB is enabled and witness_kdb is set to 1, it will cause the system 213 * to drop into kdebug() when: 214 * - a lock heirarchy violation occurs 215 * - locks are held when going to sleep. 216 */ 217#ifdef WITNESS_KDB 218int witness_kdb = 1; 219#else 220int witness_kdb = 0; 221#endif 222TUNABLE_INT("debug.witness.kdb", &witness_kdb); 223SYSCTL_INT(_debug_witness, OID_AUTO, kdb, CTLFLAG_RW, &witness_kdb, 0, ""); 224 225/* 226 * When KDB is enabled and witness_trace is set to 1, it will cause the system 227 * to print a stack trace: 228 * - a lock heirarchy violation occurs 229 * - locks are held when going to sleep. 230 */ 231int witness_trace = 1; 232TUNABLE_INT("debug.witness.trace", &witness_trace); 233SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, ""); 234#endif /* KDB */ 235 236#ifdef WITNESS_SKIPSPIN 237int witness_skipspin = 1; 238#else 239int witness_skipspin = 0; 240#endif 241TUNABLE_INT("debug.witness.skipspin", &witness_skipspin); 242SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN, 243 &witness_skipspin, 0, ""); 244 245static struct mtx w_mtx; 246static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 247static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 248static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 249static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 250static struct witness_child_list_entry *w_child_free = NULL; 251static struct lock_list_entry *w_lock_list_free = NULL; 252 253static struct witness w_data[WITNESS_COUNT]; 254static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 255static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 256 257static struct witness_order_list_entry order_lists[] = { 258 { "proctree", &lock_class_sx }, 259 { "allproc", &lock_class_sx }, 260 { "Giant", &lock_class_mtx_sleep }, 261 { "filedesc structure", &lock_class_mtx_sleep }, 262 { "pipe mutex", &lock_class_mtx_sleep }, 263 { "sigio lock", &lock_class_mtx_sleep }, 264 { "process group", &lock_class_mtx_sleep }, 265 { "process lock", &lock_class_mtx_sleep }, 266 { "session", &lock_class_mtx_sleep }, 267 { "uidinfo hash", &lock_class_mtx_sleep }, 268 { "uidinfo struct", &lock_class_mtx_sleep }, 269 { "allprison", &lock_class_mtx_sleep }, 270 { NULL, NULL }, 271 /* 272 * Sockets 273 */ 274 { "filedesc structure", &lock_class_mtx_sleep }, 275 { "accept", &lock_class_mtx_sleep }, 276 { "so_snd", &lock_class_mtx_sleep }, 277 { "so_rcv", &lock_class_mtx_sleep }, 278 { "sellck", &lock_class_mtx_sleep }, 279 { NULL, NULL }, 280 /* 281 * Routing 282 */ 283 { "so_rcv", &lock_class_mtx_sleep }, 284 { "radix node head", &lock_class_mtx_sleep }, 285 { "rtentry", &lock_class_mtx_sleep }, 286 { "ifaddr", &lock_class_mtx_sleep }, 287 { NULL, NULL }, 288 /* 289 * Multicast - protocol locks before interface locks, after UDP locks. 290 */ 291 { "udpinp", &lock_class_mtx_sleep }, 292 { "in_multi_mtx", &lock_class_mtx_sleep }, 293 { "igmp_mtx", &lock_class_mtx_sleep }, 294 { "if_addr_mtx", &lock_class_mtx_sleep }, 295 { NULL, NULL }, 296 /* 297 * UNIX Domain Sockets 298 */ 299 { "unp", &lock_class_mtx_sleep }, 300 { "so_snd", &lock_class_mtx_sleep }, 301 { NULL, NULL }, 302 /* 303 * UDP/IP 304 */ 305 { "udp", &lock_class_mtx_sleep }, 306 { "udpinp", &lock_class_mtx_sleep }, 307 { "so_snd", &lock_class_mtx_sleep }, 308 { NULL, NULL }, 309 /* 310 * TCP/IP 311 */ 312 { "tcp", &lock_class_mtx_sleep }, 313 { "tcpinp", &lock_class_mtx_sleep }, 314 { "so_snd", &lock_class_mtx_sleep }, 315 { NULL, NULL }, 316 /* 317 * SLIP 318 */ 319 { "slip_mtx", &lock_class_mtx_sleep }, 320 { "slip sc_mtx", &lock_class_mtx_sleep }, 321 { NULL, NULL }, 322 /* 323 * netatalk 324 */ 325 { "ddp_list_mtx", &lock_class_mtx_sleep }, 326 { "ddp_mtx", &lock_class_mtx_sleep }, 327 { NULL, NULL }, 328 /* 329 * BPF 330 */ 331 { "bpf global lock", &lock_class_mtx_sleep }, 332 { "bpf interface lock", &lock_class_mtx_sleep }, 333 { "bpf cdev lock", &lock_class_mtx_sleep }, 334 { NULL, NULL }, 335 /* 336 * NFS server 337 */ 338 { "nfsd_mtx", &lock_class_mtx_sleep }, 339 { "so_snd", &lock_class_mtx_sleep }, 340 { NULL, NULL }, 341 /* 342 * CDEV 343 */ 344 { "system map", &lock_class_mtx_sleep }, 345 { "vm page queue mutex", &lock_class_mtx_sleep }, 346 { "vnode interlock", &lock_class_mtx_sleep }, 347 { "cdev", &lock_class_mtx_sleep }, 348 { NULL, NULL }, 349 /* 350 * spin locks 351 */ 352#ifdef SMP 353 { "ap boot", &lock_class_mtx_spin }, 354#endif 355 { "sio", &lock_class_mtx_spin }, 356#ifdef __i386__ 357 { "cy", &lock_class_mtx_spin }, 358#endif 359 { "uart_hwmtx", &lock_class_mtx_spin }, 360 { "sabtty", &lock_class_mtx_spin }, 361 { "zstty", &lock_class_mtx_spin }, 362 { "ng_node", &lock_class_mtx_spin }, 363 { "ng_worklist", &lock_class_mtx_spin }, 364 { "taskqueue_fast", &lock_class_mtx_spin }, 365 { "intr table", &lock_class_mtx_spin }, 366 { "ithread table lock", &lock_class_mtx_spin }, 367 { "sleepq chain", &lock_class_mtx_spin }, 368 { "sched lock", &lock_class_mtx_spin }, 369 { "turnstile chain", &lock_class_mtx_spin }, 370 { "td_contested", &lock_class_mtx_spin }, 371 { "callout", &lock_class_mtx_spin }, 372 { "entropy harvest mutex", &lock_class_mtx_spin }, 373 /* 374 * leaf locks 375 */ 376 { "allpmaps", &lock_class_mtx_spin }, 377 { "vm page queue free mutex", &lock_class_mtx_spin }, 378 { "icu", &lock_class_mtx_spin }, 379#ifdef SMP 380 { "smp rendezvous", &lock_class_mtx_spin }, 381#if defined(__i386__) || defined(__amd64__) 382 { "tlb", &lock_class_mtx_spin }, 383#endif 384#ifdef __sparc64__ 385 { "ipi", &lock_class_mtx_spin }, 386 { "rtc_mtx", &lock_class_mtx_spin }, 387#endif 388#endif 389 { "clk", &lock_class_mtx_spin }, 390 { "mutex profiling lock", &lock_class_mtx_spin }, 391 { "kse zombie lock", &lock_class_mtx_spin }, 392 { "ALD Queue", &lock_class_mtx_spin }, 393#ifdef __ia64__ 394 { "MCA spin lock", &lock_class_mtx_spin }, 395#endif 396#if defined(__i386__) || defined(__amd64__) 397 { "pcicfg", &lock_class_mtx_spin }, 398 { "NDIS thread lock", &lock_class_mtx_spin }, 399#endif 400 { "tw_osl_io_lock", &lock_class_mtx_spin }, 401 { "tw_osl_q_lock", &lock_class_mtx_spin }, 402 { "tw_cl_io_lock", &lock_class_mtx_spin }, 403 { "tw_cl_intr_lock", &lock_class_mtx_spin }, 404 { "tw_cl_gen_lock", &lock_class_mtx_spin }, 405 { NULL, NULL }, 406 { NULL, NULL } 407}; 408 409#ifdef BLESSING 410/* 411 * Pairs of locks which have been blessed 412 * Don't complain about order problems with blessed locks 413 */ 414static struct witness_blessed blessed_list[] = { 415}; 416static int blessed_count = 417 sizeof(blessed_list) / sizeof(struct witness_blessed); 418#endif 419 420/* 421 * List of all locks in the system. 422 */ 423TAILQ_HEAD(, lock_object) all_locks = TAILQ_HEAD_INITIALIZER(all_locks); 424 425static struct mtx all_mtx = { 426 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 427 "All locks list", /* mtx_object.lo_name */ 428 "All locks list", /* mtx_object.lo_type */ 429 LO_INITIALIZED, /* mtx_object.lo_flags */ 430 { NULL, NULL }, /* mtx_object.lo_list */ 431 NULL }, /* mtx_object.lo_witness */ 432 MTX_UNOWNED, 0 /* mtx_lock, mtx_recurse */ 433}; 434 435/* 436 * This global is set to 0 once it becomes safe to use the witness code. 437 */ 438static int witness_cold = 1; 439 440/* 441 * Global variables for book keeping. 442 */ 443static int lock_cur_cnt; 444static int lock_max_cnt; 445 446/* 447 * The WITNESS-enabled diagnostic code. 448 */ 449static void 450witness_initialize(void *dummy __unused) 451{ 452 struct lock_object *lock; 453 struct witness_order_list_entry *order; 454 struct witness *w, *w1; 455 int i; 456 457 /* 458 * We have to release Giant before initializing its witness 459 * structure so that WITNESS doesn't get confused. 460 */ 461 mtx_unlock(&Giant); 462 mtx_assert(&Giant, MA_NOTOWNED); 463 464 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 465 TAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 466 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 467 MTX_NOWITNESS); 468 for (i = 0; i < WITNESS_COUNT; i++) 469 witness_free(&w_data[i]); 470 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 471 witness_child_free(&w_childdata[i]); 472 for (i = 0; i < LOCK_CHILDCOUNT; i++) 473 witness_lock_list_free(&w_locklistdata[i]); 474 475 /* First add in all the specified order lists. */ 476 for (order = order_lists; order->w_name != NULL; order++) { 477 w = enroll(order->w_name, order->w_class); 478 if (w == NULL) 479 continue; 480 w->w_file = "order list"; 481 for (order++; order->w_name != NULL; order++) { 482 w1 = enroll(order->w_name, order->w_class); 483 if (w1 == NULL) 484 continue; 485 w1->w_file = "order list"; 486 if (!itismychild(w, w1)) 487 panic("Not enough memory for static orders!"); 488 w = w1; 489 } 490 } 491 492 /* Iterate through all locks and add them to witness. */ 493 mtx_lock(&all_mtx); 494 TAILQ_FOREACH(lock, &all_locks, lo_list) { 495 if (lock->lo_flags & LO_WITNESS) 496 lock->lo_witness = enroll(lock->lo_type, 497 lock->lo_class); 498 else 499 lock->lo_witness = NULL; 500 } 501 mtx_unlock(&all_mtx); 502 503 /* Mark the witness code as being ready for use. */ 504 atomic_store_rel_int(&witness_cold, 0); 505 506 mtx_lock(&Giant); 507} 508SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 509 510static int 511sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS) 512{ 513 int error, value; 514 515 value = witness_watch; 516 error = sysctl_handle_int(oidp, &value, 0, req); 517 if (error != 0 || req->newptr == NULL) 518 return (error); 519 error = suser(req->td); 520 if (error != 0) 521 return (error); 522 if (value == witness_watch) 523 return (0); 524 if (value != 0) 525 return (EINVAL); 526 witness_watch = 0; 527 return (0); 528} 529 530void 531witness_init(struct lock_object *lock) 532{ 533 struct lock_class *class; 534 535 class = lock->lo_class; 536 if (lock->lo_flags & LO_INITIALIZED) 537 panic("%s: lock (%s) %s is already initialized", __func__, 538 class->lc_name, lock->lo_name); 539 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 540 (class->lc_flags & LC_RECURSABLE) == 0) 541 panic("%s: lock (%s) %s can not be recursable", __func__, 542 class->lc_name, lock->lo_name); 543 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 544 (class->lc_flags & LC_SLEEPABLE) == 0) 545 panic("%s: lock (%s) %s can not be sleepable", __func__, 546 class->lc_name, lock->lo_name); 547 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 548 (class->lc_flags & LC_UPGRADABLE) == 0) 549 panic("%s: lock (%s) %s can not be upgradable", __func__, 550 class->lc_name, lock->lo_name); 551 552 mtx_lock(&all_mtx); 553 TAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 554 lock->lo_flags |= LO_INITIALIZED; 555 lock_cur_cnt++; 556 if (lock_cur_cnt > lock_max_cnt) 557 lock_max_cnt = lock_cur_cnt; 558 mtx_unlock(&all_mtx); 559 if (!witness_cold && witness_watch != 0 && panicstr == NULL && 560 (lock->lo_flags & LO_WITNESS) != 0) 561 lock->lo_witness = enroll(lock->lo_type, class); 562 else 563 lock->lo_witness = NULL; 564} 565 566void 567witness_destroy(struct lock_object *lock) 568{ 569 struct witness *w; 570 571 if (witness_cold) 572 panic("lock (%s) %s destroyed while witness_cold", 573 lock->lo_class->lc_name, lock->lo_name); 574 if ((lock->lo_flags & LO_INITIALIZED) == 0) 575 panic("%s: lock (%s) %s is not initialized", __func__, 576 lock->lo_class->lc_name, lock->lo_name); 577 578 /* XXX: need to verify that no one holds the lock */ 579 w = lock->lo_witness; 580 if (w != NULL) { 581 mtx_lock_spin(&w_mtx); 582 MPASS(w->w_refcount > 0); 583 w->w_refcount--; 584 585 /* 586 * Lock is already released if we have an allocation failure 587 * and depart() fails. 588 */ 589 if (w->w_refcount != 0 || depart(w)) 590 mtx_unlock_spin(&w_mtx); 591 } 592 593 mtx_lock(&all_mtx); 594 lock_cur_cnt--; 595 TAILQ_REMOVE(&all_locks, lock, lo_list); 596 lock->lo_flags &= ~LO_INITIALIZED; 597 mtx_unlock(&all_mtx); 598} 599 600#ifdef DDB 601static void 602witness_display_list(void(*prnt)(const char *fmt, ...), 603 struct witness_list *list) 604{ 605 struct witness *w; 606 607 STAILQ_FOREACH(w, list, w_typelist) { 608 if (w->w_file == NULL || w->w_level > 0) 609 continue; 610 /* 611 * This lock has no anscestors, display its descendants. 612 */ 613 witness_displaydescendants(prnt, w, 0); 614 } 615} 616 617static void 618witness_display(void(*prnt)(const char *fmt, ...)) 619{ 620 struct witness *w; 621 622 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 623 witness_levelall(); 624 625 /* Clear all the displayed flags. */ 626 STAILQ_FOREACH(w, &w_all, w_list) { 627 w->w_displayed = 0; 628 } 629 630 /* 631 * First, handle sleep locks which have been acquired at least 632 * once. 633 */ 634 prnt("Sleep locks:\n"); 635 witness_display_list(prnt, &w_sleep); 636 637 /* 638 * Now do spin locks which have been acquired at least once. 639 */ 640 prnt("\nSpin locks:\n"); 641 witness_display_list(prnt, &w_spin); 642 643 /* 644 * Finally, any locks which have not been acquired yet. 645 */ 646 prnt("\nLocks which were never acquired:\n"); 647 STAILQ_FOREACH(w, &w_all, w_list) { 648 if (w->w_file != NULL || w->w_refcount == 0) 649 continue; 650 prnt("%s\n", w->w_name); 651 } 652} 653#endif /* DDB */ 654 655/* Trim useless garbage from filenames. */ 656static const char * 657fixup_filename(const char *file) 658{ 659 660 if (file == NULL) 661 return (NULL); 662 while (strncmp(file, "../", 3) == 0) 663 file += 3; 664 return (file); 665} 666 667int 668witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) 669{ 670 671 if (witness_watch == 0 || panicstr != NULL) 672 return (0); 673 674 /* Require locks that witness knows about. */ 675 if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || 676 lock2->lo_witness == NULL) 677 return (EINVAL); 678 679 MPASS(!mtx_owned(&w_mtx)); 680 mtx_lock_spin(&w_mtx); 681 682 /* 683 * If we already have either an explicit or implied lock order that 684 * is the other way around, then return an error. 685 */ 686 if (isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { 687 mtx_unlock_spin(&w_mtx); 688 return (EDOOFUS); 689 } 690 691 /* Try to add the new order. */ 692 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 693 lock2->lo_type, lock1->lo_type); 694 if (!itismychild(lock1->lo_witness, lock2->lo_witness)) 695 return (ENOMEM); 696 mtx_unlock_spin(&w_mtx); 697 return (0); 698} 699 700void 701witness_checkorder(struct lock_object *lock, int flags, const char *file, 702 int line) 703{ 704 struct lock_list_entry **lock_list, *lle; 705 struct lock_instance *lock1, *lock2; 706 struct lock_class *class; 707 struct witness *w, *w1; 708 struct thread *td; 709 int i, j; 710 711 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 712 panicstr != NULL) 713 return; 714 715 /* 716 * Try locks do not block if they fail to acquire the lock, thus 717 * there is no danger of deadlocks or of switching while holding a 718 * spin lock if we acquire a lock via a try operation. This 719 * function shouldn't even be called for try locks, so panic if 720 * that happens. 721 */ 722 if (flags & LOP_TRYLOCK) 723 panic("%s should not be called for try lock operations", 724 __func__); 725 726 w = lock->lo_witness; 727 class = lock->lo_class; 728 td = curthread; 729 file = fixup_filename(file); 730 731 if (class->lc_flags & LC_SLEEPLOCK) { 732 /* 733 * Since spin locks include a critical section, this check 734 * implicitly enforces a lock order of all sleep locks before 735 * all spin locks. 736 */ 737 if (td->td_critnest != 0 && !kdb_active) 738 panic("blockable sleep lock (%s) %s @ %s:%d", 739 class->lc_name, lock->lo_name, file, line); 740 741 /* 742 * If this is the first lock acquired then just return as 743 * no order checking is needed. 744 */ 745 if (td->td_sleeplocks == NULL) 746 return; 747 lock_list = &td->td_sleeplocks; 748 } else { 749 /* 750 * If this is the first lock, just return as no order 751 * checking is needed. We check this in both if clauses 752 * here as unifying the check would require us to use a 753 * critical section to ensure we don't migrate while doing 754 * the check. Note that if this is not the first lock, we 755 * are already in a critical section and are safe for the 756 * rest of the check. 757 */ 758 if (PCPU_GET(spinlocks) == NULL) 759 return; 760 lock_list = PCPU_PTR(spinlocks); 761 } 762 763 /* 764 * Check to see if we are recursing on a lock we already own. If 765 * so, make sure that we don't mismatch exclusive and shared lock 766 * acquires. 767 */ 768 lock1 = find_instance(*lock_list, lock); 769 if (lock1 != NULL) { 770 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 771 (flags & LOP_EXCLUSIVE) == 0) { 772 printf("shared lock of (%s) %s @ %s:%d\n", 773 class->lc_name, lock->lo_name, file, line); 774 printf("while exclusively locked from %s:%d\n", 775 lock1->li_file, lock1->li_line); 776 panic("share->excl"); 777 } 778 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 779 (flags & LOP_EXCLUSIVE) != 0) { 780 printf("exclusive lock of (%s) %s @ %s:%d\n", 781 class->lc_name, lock->lo_name, file, line); 782 printf("while share locked from %s:%d\n", 783 lock1->li_file, lock1->li_line); 784 panic("excl->share"); 785 } 786 return; 787 } 788 789 /* 790 * Try locks do not block if they fail to acquire the lock, thus 791 * there is no danger of deadlocks or of switching while holding a 792 * spin lock if we acquire a lock via a try operation. 793 */ 794 if (flags & LOP_TRYLOCK) 795 return; 796 797 /* 798 * Check for duplicate locks of the same type. Note that we only 799 * have to check for this on the last lock we just acquired. Any 800 * other cases will be caught as lock order violations. 801 */ 802 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 803 w1 = lock1->li_lock->lo_witness; 804 if (w1 == w) { 805 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK) || 806 (flags & LOP_DUPOK)) 807 return; 808 w->w_same_squawked = 1; 809 printf("acquiring duplicate lock of same type: \"%s\"\n", 810 lock->lo_type); 811 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 812 lock1->li_file, lock1->li_line); 813 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 814#ifdef KDB 815 goto debugger; 816#else 817 return; 818#endif 819 } 820 MPASS(!mtx_owned(&w_mtx)); 821 mtx_lock_spin(&w_mtx); 822 /* 823 * If we have a known higher number just say ok 824 */ 825 if (witness_watch > 1 && w->w_level > w1->w_level) { 826 mtx_unlock_spin(&w_mtx); 827 return; 828 } 829 /* 830 * If we know that the the lock we are acquiring comes after 831 * the lock we most recently acquired in the lock order tree, 832 * then there is no need for any further checks. 833 */ 834 if (isitmydescendant(w1, w)) { 835 mtx_unlock_spin(&w_mtx); 836 return; 837 } 838 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 839 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 840 841 MPASS(j < WITNESS_COUNT); 842 lock1 = &lle->ll_children[i]; 843 w1 = lock1->li_lock->lo_witness; 844 845 /* 846 * If this lock doesn't undergo witness checking, 847 * then skip it. 848 */ 849 if (w1 == NULL) { 850 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 851 ("lock missing witness structure")); 852 continue; 853 } 854 /* 855 * If we are locking Giant and this is a sleepable 856 * lock, then skip it. 857 */ 858 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && 859 lock == &Giant.mtx_object) 860 continue; 861 /* 862 * If we are locking a sleepable lock and this lock 863 * is Giant, then skip it. 864 */ 865 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 866 lock1->li_lock == &Giant.mtx_object) 867 continue; 868 /* 869 * If we are locking a sleepable lock and this lock 870 * isn't sleepable, we want to treat it as a lock 871 * order violation to enfore a general lock order of 872 * sleepable locks before non-sleepable locks. 873 */ 874 if (!((lock->lo_flags & LO_SLEEPABLE) != 0 && 875 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 876 /* 877 * Check the lock order hierarchy for a reveresal. 878 */ 879 if (!isitmydescendant(w, w1)) 880 continue; 881 /* 882 * We have a lock order violation, check to see if it 883 * is allowed or has already been yelled about. 884 */ 885 mtx_unlock_spin(&w_mtx); 886#ifdef BLESSING 887 /* 888 * If the lock order is blessed, just bail. We don't 889 * look for other lock order violations though, which 890 * may be a bug. 891 */ 892 if (blessed(w, w1)) 893 return; 894#endif 895 if (lock1->li_lock == &Giant.mtx_object) { 896 if (w1->w_Giant_squawked) 897 return; 898 else 899 w1->w_Giant_squawked = 1; 900 } else { 901 if (w1->w_other_squawked) 902 return; 903 else 904 w1->w_other_squawked = 1; 905 } 906 /* 907 * Ok, yell about it. 908 */ 909 printf("lock order reversal\n"); 910 /* 911 * Try to locate an earlier lock with 912 * witness w in our list. 913 */ 914 do { 915 lock2 = &lle->ll_children[i]; 916 MPASS(lock2->li_lock != NULL); 917 if (lock2->li_lock->lo_witness == w) 918 break; 919 if (i == 0 && lle->ll_next != NULL) { 920 lle = lle->ll_next; 921 i = lle->ll_count - 1; 922 MPASS(i >= 0 && i < LOCK_NCHILDREN); 923 } else 924 i--; 925 } while (i >= 0); 926 if (i < 0) { 927 printf(" 1st %p %s (%s) @ %s:%d\n", 928 lock1->li_lock, lock1->li_lock->lo_name, 929 lock1->li_lock->lo_type, lock1->li_file, 930 lock1->li_line); 931 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 932 lock->lo_name, lock->lo_type, file, line); 933 } else { 934 printf(" 1st %p %s (%s) @ %s:%d\n", 935 lock2->li_lock, lock2->li_lock->lo_name, 936 lock2->li_lock->lo_type, lock2->li_file, 937 lock2->li_line); 938 printf(" 2nd %p %s (%s) @ %s:%d\n", 939 lock1->li_lock, lock1->li_lock->lo_name, 940 lock1->li_lock->lo_type, lock1->li_file, 941 lock1->li_line); 942 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 943 lock->lo_name, lock->lo_type, file, line); 944 } 945#ifdef KDB 946 goto debugger; 947#else 948 return; 949#endif 950 } 951 } 952 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 953 /* 954 * If requested, build a new lock order. However, don't build a new 955 * relationship between a sleepable lock and Giant if it is in the 956 * wrong direction. The correct lock order is that sleepable locks 957 * always come before Giant. 958 */ 959 if (flags & LOP_NEWORDER && 960 !(lock1->li_lock == &Giant.mtx_object && 961 (lock->lo_flags & LO_SLEEPABLE) != 0)) { 962 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 963 lock->lo_type, lock1->li_lock->lo_type); 964 if (!itismychild(lock1->li_lock->lo_witness, w)) 965 /* Witness is dead. */ 966 return; 967 } 968 mtx_unlock_spin(&w_mtx); 969 return; 970 971#ifdef KDB 972debugger: 973 if (witness_trace) 974 kdb_backtrace(); 975 if (witness_kdb) 976 kdb_enter(__func__); 977#endif 978} 979 980void 981witness_lock(struct lock_object *lock, int flags, const char *file, int line) 982{ 983 struct lock_list_entry **lock_list, *lle; 984 struct lock_instance *instance; 985 struct witness *w; 986 struct thread *td; 987 988 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 989 panicstr != NULL) 990 return; 991 w = lock->lo_witness; 992 td = curthread; 993 file = fixup_filename(file); 994 995 /* Determine lock list for this lock. */ 996 if (lock->lo_class->lc_flags & LC_SLEEPLOCK) 997 lock_list = &td->td_sleeplocks; 998 else 999 lock_list = PCPU_PTR(spinlocks); 1000 1001 /* Check to see if we are recursing on a lock we already own. */ 1002 instance = find_instance(*lock_list, lock); 1003 if (instance != NULL) { 1004 instance->li_flags++; 1005 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 1006 td->td_proc->p_pid, lock->lo_name, 1007 instance->li_flags & LI_RECURSEMASK); 1008 instance->li_file = file; 1009 instance->li_line = line; 1010 return; 1011 } 1012 1013 /* Update per-witness last file and line acquire. */ 1014 w->w_file = file; 1015 w->w_line = line; 1016 1017 /* Find the next open lock instance in the list and fill it. */ 1018 lle = *lock_list; 1019 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 1020 lle = witness_lock_list_get(); 1021 if (lle == NULL) 1022 return; 1023 lle->ll_next = *lock_list; 1024 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 1025 td->td_proc->p_pid, lle); 1026 *lock_list = lle; 1027 } 1028 instance = &lle->ll_children[lle->ll_count++]; 1029 instance->li_lock = lock; 1030 instance->li_line = line; 1031 instance->li_file = file; 1032 if ((flags & LOP_EXCLUSIVE) != 0) 1033 instance->li_flags = LI_EXCLUSIVE; 1034 else 1035 instance->li_flags = 0; 1036 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 1037 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 1038} 1039 1040void 1041witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 1042{ 1043 struct lock_instance *instance; 1044 struct lock_class *class; 1045 1046 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1047 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1048 return; 1049 class = lock->lo_class; 1050 file = fixup_filename(file); 1051 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1052 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 1053 class->lc_name, lock->lo_name, file, line); 1054 if ((flags & LOP_TRYLOCK) == 0) 1055 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 1056 lock->lo_name, file, line); 1057 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1058 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 1059 class->lc_name, lock->lo_name, file, line); 1060 instance = find_instance(curthread->td_sleeplocks, lock); 1061 if (instance == NULL) 1062 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 1063 class->lc_name, lock->lo_name, file, line); 1064 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 1065 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 1066 class->lc_name, lock->lo_name, file, line); 1067 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1068 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 1069 class->lc_name, lock->lo_name, 1070 instance->li_flags & LI_RECURSEMASK, file, line); 1071 instance->li_flags |= LI_EXCLUSIVE; 1072} 1073 1074void 1075witness_downgrade(struct lock_object *lock, int flags, const char *file, 1076 int line) 1077{ 1078 struct lock_instance *instance; 1079 struct lock_class *class; 1080 1081 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1082 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1083 return; 1084 class = lock->lo_class; 1085 file = fixup_filename(file); 1086 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1087 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 1088 class->lc_name, lock->lo_name, file, line); 1089 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1090 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 1091 class->lc_name, lock->lo_name, file, line); 1092 instance = find_instance(curthread->td_sleeplocks, lock); 1093 if (instance == NULL) 1094 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 1095 class->lc_name, lock->lo_name, file, line); 1096 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 1097 panic("downgrade of shared lock (%s) %s @ %s:%d", 1098 class->lc_name, lock->lo_name, file, line); 1099 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1100 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 1101 class->lc_name, lock->lo_name, 1102 instance->li_flags & LI_RECURSEMASK, file, line); 1103 instance->li_flags &= ~LI_EXCLUSIVE; 1104} 1105 1106void 1107witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 1108{ 1109 struct lock_list_entry **lock_list, *lle; 1110 struct lock_instance *instance; 1111 struct lock_class *class; 1112 struct thread *td; 1113 register_t s; 1114 int i, j; 1115 1116 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1117 panicstr != NULL) 1118 return; 1119 td = curthread; 1120 class = lock->lo_class; 1121 file = fixup_filename(file); 1122 1123 /* Find lock instance associated with this lock. */ 1124 if (class->lc_flags & LC_SLEEPLOCK) 1125 lock_list = &td->td_sleeplocks; 1126 else 1127 lock_list = PCPU_PTR(spinlocks); 1128 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 1129 for (i = 0; i < (*lock_list)->ll_count; i++) { 1130 instance = &(*lock_list)->ll_children[i]; 1131 if (instance->li_lock == lock) 1132 goto found; 1133 } 1134 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 1135 file, line); 1136found: 1137 1138 /* First, check for shared/exclusive mismatches. */ 1139 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 1140 (flags & LOP_EXCLUSIVE) == 0) { 1141 printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name, 1142 lock->lo_name, file, line); 1143 printf("while exclusively locked from %s:%d\n", 1144 instance->li_file, instance->li_line); 1145 panic("excl->ushare"); 1146 } 1147 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 1148 (flags & LOP_EXCLUSIVE) != 0) { 1149 printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name, 1150 lock->lo_name, file, line); 1151 printf("while share locked from %s:%d\n", instance->li_file, 1152 instance->li_line); 1153 panic("share->uexcl"); 1154 } 1155 1156 /* If we are recursed, unrecurse. */ 1157 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 1158 CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, 1159 td->td_proc->p_pid, instance->li_lock->lo_name, 1160 instance->li_flags); 1161 instance->li_flags--; 1162 return; 1163 } 1164 1165 /* Otherwise, remove this item from the list. */ 1166 s = intr_disable(); 1167 CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, 1168 td->td_proc->p_pid, instance->li_lock->lo_name, 1169 (*lock_list)->ll_count - 1); 1170 for (j = i; j < (*lock_list)->ll_count - 1; j++) 1171 (*lock_list)->ll_children[j] = 1172 (*lock_list)->ll_children[j + 1]; 1173 (*lock_list)->ll_count--; 1174 intr_restore(s); 1175 1176 /* If this lock list entry is now empty, free it. */ 1177 if ((*lock_list)->ll_count == 0) { 1178 lle = *lock_list; 1179 *lock_list = lle->ll_next; 1180 CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, 1181 td->td_proc->p_pid, lle); 1182 witness_lock_list_free(lle); 1183 } 1184} 1185 1186/* 1187 * Warn if any locks other than 'lock' are held. Flags can be passed in to 1188 * exempt Giant and sleepable locks from the checks as well. If any 1189 * non-exempt locks are held, then a supplied message is printed to the 1190 * console along with a list of the offending locks. If indicated in the 1191 * flags then a failure results in a panic as well. 1192 */ 1193int 1194witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) 1195{ 1196 struct lock_list_entry *lle; 1197 struct lock_instance *lock1; 1198 struct thread *td; 1199 va_list ap; 1200 int i, n; 1201 1202 if (witness_cold || witness_watch == 0 || panicstr != NULL) 1203 return (0); 1204 n = 0; 1205 td = curthread; 1206 for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next) 1207 for (i = lle->ll_count - 1; i >= 0; i--) { 1208 lock1 = &lle->ll_children[i]; 1209 if (lock1->li_lock == lock) 1210 continue; 1211 if (flags & WARN_GIANTOK && 1212 lock1->li_lock == &Giant.mtx_object) 1213 continue; 1214 if (flags & WARN_SLEEPOK && 1215 (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) 1216 continue; 1217 if (n == 0) { 1218 va_start(ap, fmt); 1219 vprintf(fmt, ap); 1220 va_end(ap); 1221 printf(" with the following"); 1222 if (flags & WARN_SLEEPOK) 1223 printf(" non-sleepable"); 1224 printf(" locks held:\n"); 1225 } 1226 n++; 1227 witness_list_lock(lock1); 1228 } 1229 if (PCPU_GET(spinlocks) != NULL) { 1230 /* 1231 * Since we already hold a spinlock preemption is 1232 * already blocked. 1233 */ 1234 if (n == 0) { 1235 va_start(ap, fmt); 1236 vprintf(fmt, ap); 1237 va_end(ap); 1238 printf(" with the following"); 1239 if (flags & WARN_SLEEPOK) 1240 printf(" non-sleepable"); 1241 printf(" locks held:\n"); 1242 } 1243 n += witness_list_locks(PCPU_PTR(spinlocks)); 1244 } 1245 if (flags & WARN_PANIC && n) 1246 panic("witness_warn"); 1247#ifdef KDB 1248 else if (witness_kdb && n) 1249 kdb_enter(__func__); 1250 else if (witness_trace && n) 1251 kdb_backtrace(); 1252#endif 1253 return (n); 1254} 1255 1256const char * 1257witness_file(struct lock_object *lock) 1258{ 1259 struct witness *w; 1260 1261 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1262 return ("?"); 1263 w = lock->lo_witness; 1264 return (w->w_file); 1265} 1266 1267int 1268witness_line(struct lock_object *lock) 1269{ 1270 struct witness *w; 1271 1272 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1273 return (0); 1274 w = lock->lo_witness; 1275 return (w->w_line); 1276} 1277 1278static struct witness * 1279enroll(const char *description, struct lock_class *lock_class) 1280{ 1281 struct witness *w; 1282 1283 if (witness_watch == 0 || panicstr != NULL) 1284 return (NULL); 1285 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 1286 return (NULL); 1287 mtx_lock_spin(&w_mtx); 1288 STAILQ_FOREACH(w, &w_all, w_list) { 1289 if (w->w_name == description || (w->w_refcount > 0 && 1290 strcmp(description, w->w_name) == 0)) { 1291 w->w_refcount++; 1292 mtx_unlock_spin(&w_mtx); 1293 if (lock_class != w->w_class) 1294 panic( 1295 "lock (%s) %s does not match earlier (%s) lock", 1296 description, lock_class->lc_name, 1297 w->w_class->lc_name); 1298 return (w); 1299 } 1300 } 1301 /* 1302 * This isn't quite right, as witness_cold is still 0 while we 1303 * enroll all the locks initialized before witness_initialize(). 1304 */ 1305 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 1306 mtx_unlock_spin(&w_mtx); 1307 panic("spin lock %s not in order list", description); 1308 } 1309 if ((w = witness_get()) == NULL) 1310 return (NULL); 1311 w->w_name = description; 1312 w->w_class = lock_class; 1313 w->w_refcount = 1; 1314 STAILQ_INSERT_HEAD(&w_all, w, w_list); 1315 if (lock_class->lc_flags & LC_SPINLOCK) 1316 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 1317 else if (lock_class->lc_flags & LC_SLEEPLOCK) 1318 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 1319 else { 1320 mtx_unlock_spin(&w_mtx); 1321 panic("lock class %s is not sleep or spin", 1322 lock_class->lc_name); 1323 } 1324 mtx_unlock_spin(&w_mtx); 1325 return (w); 1326} 1327 1328/* Don't let the door bang you on the way out... */ 1329static int 1330depart(struct witness *w) 1331{ 1332 struct witness_child_list_entry *wcl, *nwcl; 1333 struct witness_list *list; 1334 struct witness *parent; 1335 1336 MPASS(w->w_refcount == 0); 1337 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1338 list = &w_sleep; 1339 else 1340 list = &w_spin; 1341 /* 1342 * First, we run through the entire tree looking for any 1343 * witnesses that the outgoing witness is a child of. For 1344 * each parent that we find, we reparent all the direct 1345 * children of the outgoing witness to its parent. 1346 */ 1347 STAILQ_FOREACH(parent, list, w_typelist) { 1348 if (!isitmychild(parent, w)) 1349 continue; 1350 removechild(parent, w); 1351 if (!reparentchildren(parent, w)) 1352 return (0); 1353 } 1354 1355 /* 1356 * Now we go through and free up the child list of the 1357 * outgoing witness. 1358 */ 1359 for (wcl = w->w_children; wcl != NULL; wcl = nwcl) { 1360 nwcl = wcl->wcl_next; 1361 witness_child_free(wcl); 1362 } 1363 1364 /* 1365 * Detach from various lists and free. 1366 */ 1367 STAILQ_REMOVE(list, w, witness, w_typelist); 1368 STAILQ_REMOVE(&w_all, w, witness, w_list); 1369 witness_free(w); 1370 1371 /* Finally, fixup the tree. */ 1372 return (rebalancetree(list)); 1373} 1374 1375/* 1376 * Prune an entire lock order tree. We look for cases where a lock 1377 * is now both a descendant and a direct child of a given lock. In 1378 * that case, we want to remove the direct child link from the tree. 1379 * 1380 * Returns false if insertchild() fails. 1381 */ 1382static int 1383rebalancetree(struct witness_list *list) 1384{ 1385 struct witness *child, *parent; 1386 1387 STAILQ_FOREACH(child, list, w_typelist) { 1388 STAILQ_FOREACH(parent, list, w_typelist) { 1389 if (!isitmychild(parent, child)) 1390 continue; 1391 removechild(parent, child); 1392 if (isitmydescendant(parent, child)) 1393 continue; 1394 if (!insertchild(parent, child)) 1395 return (0); 1396 } 1397 } 1398 witness_levelall(); 1399 return (1); 1400} 1401 1402/* 1403 * Add "child" as a direct child of "parent". Returns false if 1404 * we fail due to out of memory. 1405 */ 1406static int 1407insertchild(struct witness *parent, struct witness *child) 1408{ 1409 struct witness_child_list_entry **wcl; 1410 1411 MPASS(child != NULL && parent != NULL); 1412 1413 /* 1414 * Insert "child" after "parent" 1415 */ 1416 wcl = &parent->w_children; 1417 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1418 wcl = &(*wcl)->wcl_next; 1419 if (*wcl == NULL) { 1420 *wcl = witness_child_get(); 1421 if (*wcl == NULL) 1422 return (0); 1423 } 1424 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1425 1426 return (1); 1427} 1428 1429/* 1430 * Make all the direct descendants of oldparent be direct descendants 1431 * of newparent. 1432 */ 1433static int 1434reparentchildren(struct witness *newparent, struct witness *oldparent) 1435{ 1436 struct witness_child_list_entry *wcl; 1437 int i; 1438 1439 /* Avoid making a witness a child of itself. */ 1440 MPASS(!isitmychild(oldparent, newparent)); 1441 1442 for (wcl = oldparent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1443 for (i = 0; i < wcl->wcl_count; i++) 1444 if (!insertchild(newparent, wcl->wcl_children[i])) 1445 return (0); 1446 return (1); 1447} 1448 1449static int 1450itismychild(struct witness *parent, struct witness *child) 1451{ 1452 struct witness_list *list; 1453 1454 MPASS(child != NULL && parent != NULL); 1455 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 1456 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 1457 panic( 1458 "%s: parent (%s) and child (%s) are not the same lock type", 1459 __func__, parent->w_class->lc_name, 1460 child->w_class->lc_name); 1461 1462 if (!insertchild(parent, child)) 1463 return (0); 1464 1465 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1466 list = &w_sleep; 1467 else 1468 list = &w_spin; 1469 return (rebalancetree(list)); 1470} 1471 1472static void 1473removechild(struct witness *parent, struct witness *child) 1474{ 1475 struct witness_child_list_entry **wcl, *wcl1; 1476 int i; 1477 1478 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1479 for (i = 0; i < (*wcl)->wcl_count; i++) 1480 if ((*wcl)->wcl_children[i] == child) 1481 goto found; 1482 return; 1483found: 1484 (*wcl)->wcl_count--; 1485 if ((*wcl)->wcl_count > i) 1486 (*wcl)->wcl_children[i] = 1487 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1488 MPASS((*wcl)->wcl_children[i] != NULL); 1489 if ((*wcl)->wcl_count != 0) 1490 return; 1491 wcl1 = *wcl; 1492 *wcl = wcl1->wcl_next; 1493 witness_child_free(wcl1); 1494} 1495 1496static int 1497isitmychild(struct witness *parent, struct witness *child) 1498{ 1499 struct witness_child_list_entry *wcl; 1500 int i; 1501 1502 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1503 for (i = 0; i < wcl->wcl_count; i++) { 1504 if (wcl->wcl_children[i] == child) 1505 return (1); 1506 } 1507 } 1508 return (0); 1509} 1510 1511static int 1512isitmydescendant(struct witness *parent, struct witness *child) 1513{ 1514 struct witness_child_list_entry *wcl; 1515 int i, j; 1516 1517 if (isitmychild(parent, child)) 1518 return (1); 1519 j = 0; 1520 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1521 MPASS(j < 1000); 1522 for (i = 0; i < wcl->wcl_count; i++) { 1523 if (isitmydescendant(wcl->wcl_children[i], child)) 1524 return (1); 1525 } 1526 j++; 1527 } 1528 return (0); 1529} 1530 1531static void 1532witness_levelall (void) 1533{ 1534 struct witness_list *list; 1535 struct witness *w, *w1; 1536 1537 /* 1538 * First clear all levels. 1539 */ 1540 STAILQ_FOREACH(w, &w_all, w_list) { 1541 w->w_level = 0; 1542 } 1543 1544 /* 1545 * Look for locks with no parent and level all their descendants. 1546 */ 1547 STAILQ_FOREACH(w, &w_all, w_list) { 1548 /* 1549 * This is just an optimization, technically we could get 1550 * away just walking the all list each time. 1551 */ 1552 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1553 list = &w_sleep; 1554 else 1555 list = &w_spin; 1556 STAILQ_FOREACH(w1, list, w_typelist) { 1557 if (isitmychild(w1, w)) 1558 goto skip; 1559 } 1560 witness_leveldescendents(w, 0); 1561 skip: 1562 ; /* silence GCC 3.x */ 1563 } 1564} 1565 1566static void 1567witness_leveldescendents(struct witness *parent, int level) 1568{ 1569 struct witness_child_list_entry *wcl; 1570 int i; 1571 1572 if (parent->w_level < level) 1573 parent->w_level = level; 1574 level++; 1575 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1576 for (i = 0; i < wcl->wcl_count; i++) 1577 witness_leveldescendents(wcl->wcl_children[i], level); 1578} 1579 1580static void 1581witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1582 struct witness *parent, int indent) 1583{ 1584 struct witness_child_list_entry *wcl; 1585 int i, level; 1586 1587 level = parent->w_level; 1588 prnt("%-2d", level); 1589 for (i = 0; i < indent; i++) 1590 prnt(" "); 1591 if (parent->w_refcount > 0) 1592 prnt("%s", parent->w_name); 1593 else 1594 prnt("(dead)"); 1595 if (parent->w_displayed) { 1596 prnt(" -- (already displayed)\n"); 1597 return; 1598 } 1599 parent->w_displayed = 1; 1600 if (parent->w_refcount > 0) { 1601 if (parent->w_file != NULL) 1602 prnt(" -- last acquired @ %s:%d", parent->w_file, 1603 parent->w_line); 1604 } 1605 prnt("\n"); 1606 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1607 for (i = 0; i < wcl->wcl_count; i++) 1608 witness_displaydescendants(prnt, 1609 wcl->wcl_children[i], indent + 1); 1610} 1611 1612#ifdef BLESSING 1613static int 1614blessed(struct witness *w1, struct witness *w2) 1615{ 1616 int i; 1617 struct witness_blessed *b; 1618 1619 for (i = 0; i < blessed_count; i++) { 1620 b = &blessed_list[i]; 1621 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1622 if (strcmp(w2->w_name, b->b_lock2) == 0) 1623 return (1); 1624 continue; 1625 } 1626 if (strcmp(w1->w_name, b->b_lock2) == 0) 1627 if (strcmp(w2->w_name, b->b_lock1) == 0) 1628 return (1); 1629 } 1630 return (0); 1631} 1632#endif 1633 1634static struct witness * 1635witness_get(void) 1636{ 1637 struct witness *w; 1638 1639 if (witness_watch == 0) { 1640 mtx_unlock_spin(&w_mtx); 1641 return (NULL); 1642 } 1643 if (STAILQ_EMPTY(&w_free)) { 1644 witness_watch = 0; 1645 mtx_unlock_spin(&w_mtx); 1646 printf("%s: witness exhausted\n", __func__); 1647 return (NULL); 1648 } 1649 w = STAILQ_FIRST(&w_free); 1650 STAILQ_REMOVE_HEAD(&w_free, w_list); 1651 bzero(w, sizeof(*w)); 1652 return (w); 1653} 1654 1655static void 1656witness_free(struct witness *w) 1657{ 1658 1659 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1660} 1661 1662static struct witness_child_list_entry * 1663witness_child_get(void) 1664{ 1665 struct witness_child_list_entry *wcl; 1666 1667 if (witness_watch == 0) { 1668 mtx_unlock_spin(&w_mtx); 1669 return (NULL); 1670 } 1671 wcl = w_child_free; 1672 if (wcl == NULL) { 1673 witness_watch = 0; 1674 mtx_unlock_spin(&w_mtx); 1675 printf("%s: witness exhausted\n", __func__); 1676 return (NULL); 1677 } 1678 w_child_free = wcl->wcl_next; 1679 bzero(wcl, sizeof(*wcl)); 1680 return (wcl); 1681} 1682 1683static void 1684witness_child_free(struct witness_child_list_entry *wcl) 1685{ 1686 1687 wcl->wcl_next = w_child_free; 1688 w_child_free = wcl; 1689} 1690 1691static struct lock_list_entry * 1692witness_lock_list_get(void) 1693{ 1694 struct lock_list_entry *lle; 1695 1696 if (witness_watch == 0) 1697 return (NULL); 1698 mtx_lock_spin(&w_mtx); 1699 lle = w_lock_list_free; 1700 if (lle == NULL) { 1701 witness_watch = 0; 1702 mtx_unlock_spin(&w_mtx); 1703 printf("%s: witness exhausted\n", __func__); 1704 return (NULL); 1705 } 1706 w_lock_list_free = lle->ll_next; 1707 mtx_unlock_spin(&w_mtx); 1708 bzero(lle, sizeof(*lle)); 1709 return (lle); 1710} 1711 1712static void 1713witness_lock_list_free(struct lock_list_entry *lle) 1714{ 1715 1716 mtx_lock_spin(&w_mtx); 1717 lle->ll_next = w_lock_list_free; 1718 w_lock_list_free = lle; 1719 mtx_unlock_spin(&w_mtx); 1720} 1721 1722static struct lock_instance * 1723find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1724{ 1725 struct lock_list_entry *lle; 1726 struct lock_instance *instance; 1727 int i; 1728 1729 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1730 for (i = lle->ll_count - 1; i >= 0; i--) { 1731 instance = &lle->ll_children[i]; 1732 if (instance->li_lock == lock) 1733 return (instance); 1734 } 1735 return (NULL); 1736} 1737 1738static void 1739witness_list_lock(struct lock_instance *instance) 1740{ 1741 struct lock_object *lock; 1742 1743 lock = instance->li_lock; 1744 printf("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1745 "exclusive" : "shared", lock->lo_class->lc_name, lock->lo_name); 1746 if (lock->lo_type != lock->lo_name) 1747 printf(" (%s)", lock->lo_type); 1748 printf(" r = %d (%p) locked @ %s:%d\n", 1749 instance->li_flags & LI_RECURSEMASK, lock, instance->li_file, 1750 instance->li_line); 1751} 1752 1753#ifdef DDB 1754static int 1755witness_thread_has_locks(struct thread *td) 1756{ 1757 1758 return (td->td_sleeplocks != NULL); 1759} 1760 1761static int 1762witness_proc_has_locks(struct proc *p) 1763{ 1764 struct thread *td; 1765 1766 FOREACH_THREAD_IN_PROC(p, td) { 1767 if (witness_thread_has_locks(td)) 1768 return (1); 1769 } 1770 return (0); 1771} 1772#endif 1773 1774int 1775witness_list_locks(struct lock_list_entry **lock_list) 1776{ 1777 struct lock_list_entry *lle; 1778 int i, nheld; 1779 1780 nheld = 0; 1781 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1782 for (i = lle->ll_count - 1; i >= 0; i--) { 1783 witness_list_lock(&lle->ll_children[i]); 1784 nheld++; 1785 } 1786 return (nheld); 1787} 1788 1789/* 1790 * This is a bit risky at best. We call this function when we have timed 1791 * out acquiring a spin lock, and we assume that the other CPU is stuck 1792 * with this lock held. So, we go groveling around in the other CPU's 1793 * per-cpu data to try to find the lock instance for this spin lock to 1794 * see when it was last acquired. 1795 */ 1796void 1797witness_display_spinlock(struct lock_object *lock, struct thread *owner) 1798{ 1799 struct lock_instance *instance; 1800 struct pcpu *pc; 1801 1802 if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU) 1803 return; 1804 pc = pcpu_find(owner->td_oncpu); 1805 instance = find_instance(pc->pc_spinlocks, lock); 1806 if (instance != NULL) 1807 witness_list_lock(instance); 1808} 1809 1810void 1811witness_save(struct lock_object *lock, const char **filep, int *linep) 1812{ 1813 struct lock_instance *instance; 1814 1815 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1816 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1817 return; 1818 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1819 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1820 lock->lo_class->lc_name, lock->lo_name); 1821 instance = find_instance(curthread->td_sleeplocks, lock); 1822 if (instance == NULL) 1823 panic("%s: lock (%s) %s not locked", __func__, 1824 lock->lo_class->lc_name, lock->lo_name); 1825 *filep = instance->li_file; 1826 *linep = instance->li_line; 1827} 1828 1829void 1830witness_restore(struct lock_object *lock, const char *file, int line) 1831{ 1832 struct lock_instance *instance; 1833 1834 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1835 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1836 return; 1837 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1838 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1839 lock->lo_class->lc_name, lock->lo_name); 1840 instance = find_instance(curthread->td_sleeplocks, lock); 1841 if (instance == NULL) 1842 panic("%s: lock (%s) %s not locked", __func__, 1843 lock->lo_class->lc_name, lock->lo_name); 1844 lock->lo_witness->w_file = file; 1845 lock->lo_witness->w_line = line; 1846 instance->li_file = file; 1847 instance->li_line = line; 1848} 1849 1850void 1851witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1852{ 1853#ifdef INVARIANT_SUPPORT 1854 struct lock_instance *instance; 1855 1856 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1857 return; 1858 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1859 instance = find_instance(curthread->td_sleeplocks, lock); 1860 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1861 instance = find_instance(PCPU_GET(spinlocks), lock); 1862 else { 1863 panic("Lock (%s) %s is not sleep or spin!", 1864 lock->lo_class->lc_name, lock->lo_name); 1865 } 1866 file = fixup_filename(file); 1867 switch (flags) { 1868 case LA_UNLOCKED: 1869 if (instance != NULL) 1870 panic("Lock (%s) %s locked @ %s:%d.", 1871 lock->lo_class->lc_name, lock->lo_name, file, line); 1872 break; 1873 case LA_LOCKED: 1874 case LA_LOCKED | LA_RECURSED: 1875 case LA_LOCKED | LA_NOTRECURSED: 1876 case LA_SLOCKED: 1877 case LA_SLOCKED | LA_RECURSED: 1878 case LA_SLOCKED | LA_NOTRECURSED: 1879 case LA_XLOCKED: 1880 case LA_XLOCKED | LA_RECURSED: 1881 case LA_XLOCKED | LA_NOTRECURSED: 1882 if (instance == NULL) { 1883 panic("Lock (%s) %s not locked @ %s:%d.", 1884 lock->lo_class->lc_name, lock->lo_name, file, line); 1885 break; 1886 } 1887 if ((flags & LA_XLOCKED) != 0 && 1888 (instance->li_flags & LI_EXCLUSIVE) == 0) 1889 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1890 lock->lo_class->lc_name, lock->lo_name, file, line); 1891 if ((flags & LA_SLOCKED) != 0 && 1892 (instance->li_flags & LI_EXCLUSIVE) != 0) 1893 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1894 lock->lo_class->lc_name, lock->lo_name, file, line); 1895 if ((flags & LA_RECURSED) != 0 && 1896 (instance->li_flags & LI_RECURSEMASK) == 0) 1897 panic("Lock (%s) %s not recursed @ %s:%d.", 1898 lock->lo_class->lc_name, lock->lo_name, file, line); 1899 if ((flags & LA_NOTRECURSED) != 0 && 1900 (instance->li_flags & LI_RECURSEMASK) != 0) 1901 panic("Lock (%s) %s recursed @ %s:%d.", 1902 lock->lo_class->lc_name, lock->lo_name, file, line); 1903 break; 1904 default: 1905 panic("Invalid lock assertion at %s:%d.", file, line); 1906 1907 } 1908#endif /* INVARIANT_SUPPORT */ 1909} 1910 1911#ifdef DDB 1912static void 1913witness_list(struct thread *td) 1914{ 1915 1916 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1917 KASSERT(kdb_active, ("%s: not in the debugger", __func__)); 1918 1919 if (witness_watch == 0) 1920 return; 1921 1922 witness_list_locks(&td->td_sleeplocks); 1923 1924 /* 1925 * We only handle spinlocks if td == curthread. This is somewhat broken 1926 * if td is currently executing on some other CPU and holds spin locks 1927 * as we won't display those locks. If we had a MI way of getting 1928 * the per-cpu data for a given cpu then we could use 1929 * td->td_oncpu to get the list of spinlocks for this thread 1930 * and "fix" this. 1931 * 1932 * That still wouldn't really fix this unless we locked sched_lock 1933 * or stopped the other CPU to make sure it wasn't changing the list 1934 * out from under us. It is probably best to just not try to handle 1935 * threads on other CPU's for now. 1936 */ 1937 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1938 witness_list_locks(PCPU_PTR(spinlocks)); 1939} 1940 1941DB_SHOW_COMMAND(locks, db_witness_list) 1942{ 1943 struct thread *td; 1944 pid_t pid; 1945 struct proc *p; 1946 1947 if (have_addr) { 1948 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1949 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1950 ((addr >> 16) % 16) * 10000; 1951 /* sx_slock(&allproc_lock); */ 1952 FOREACH_PROC_IN_SYSTEM(p) { 1953 if (p->p_pid == pid) 1954 break; 1955 } 1956 /* sx_sunlock(&allproc_lock); */ 1957 if (p == NULL) { 1958 db_printf("pid %d not found\n", pid); 1959 return; 1960 } 1961 FOREACH_THREAD_IN_PROC(p, td) { 1962 witness_list(td); 1963 } 1964 } else { 1965 td = curthread; 1966 witness_list(td); 1967 } 1968} 1969 1970DB_SHOW_COMMAND(alllocks, db_witness_list_all) 1971{ 1972 struct thread *td; 1973 struct proc *p; 1974 1975 /* 1976 * It would be nice to list only threads and processes that actually 1977 * held sleep locks, but that information is currently not exported 1978 * by WITNESS. 1979 */ 1980 FOREACH_PROC_IN_SYSTEM(p) { 1981 if (!witness_proc_has_locks(p)) 1982 continue; 1983 FOREACH_THREAD_IN_PROC(p, td) { 1984 if (!witness_thread_has_locks(td)) 1985 continue; 1986 printf("Process %d (%s) thread %p (%d)\n", p->p_pid, 1987 p->p_comm, td, td->td_tid); 1988 witness_list(td); 1989 } 1990 } 1991} 1992 1993DB_SHOW_COMMAND(witness, db_witness_display) 1994{ 1995 1996 witness_display(db_printf); 1997} 1998#endif 1999