subr_witness.c revision 149738
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 149738 2005-09-02 20:23:49Z jhb $"); 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 void removechild(struct witness *parent, struct witness *child); 169static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS); 170static void witness_displaydescendants(void(*)(const char *fmt, ...), 171 struct witness *, int indent); 172static const char *fixup_filename(const char *file); 173static void witness_leveldescendents(struct witness *parent, int level); 174static void witness_levelall(void); 175static struct witness *witness_get(void); 176static void witness_free(struct witness *m); 177static struct witness_child_list_entry *witness_child_get(void); 178static void witness_child_free(struct witness_child_list_entry *wcl); 179static struct lock_list_entry *witness_lock_list_get(void); 180static void witness_lock_list_free(struct lock_list_entry *lle); 181static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 182 struct lock_object *lock); 183static void witness_list_lock(struct lock_instance *instance); 184#ifdef DDB 185static void witness_list(struct thread *td); 186static void witness_display_list(void(*prnt)(const char *fmt, ...), 187 struct witness_list *list); 188static void witness_display(void(*)(const char *fmt, ...)); 189#endif 190 191SYSCTL_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 */ 199static int witness_watch = 1; 200TUNABLE_INT("debug.witness.watch", &witness_watch); 201SYSCTL_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 212int witness_kdb = 1; 213#else 214int witness_kdb = 0; 215#endif 216TUNABLE_INT("debug.witness.kdb", &witness_kdb); 217SYSCTL_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 */ 225int witness_trace = 1; 226TUNABLE_INT("debug.witness.trace", &witness_trace); 227SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, ""); 228#endif /* KDB */ 229 230#ifdef WITNESS_SKIPSPIN 231int witness_skipspin = 1; 232#else 233int witness_skipspin = 0; 234#endif 235TUNABLE_INT("debug.witness.skipspin", &witness_skipspin); 236SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN, 237 &witness_skipspin, 0, ""); 238 239static struct mtx w_mtx; 240static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 241static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 242static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 243static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 244static struct witness_child_list_entry *w_child_free = NULL; 245static struct lock_list_entry *w_lock_list_free = NULL; 246 247static int w_free_cnt, w_spin_cnt, w_sleep_cnt, w_child_free_cnt, w_child_cnt; 248SYSCTL_INT(_debug_witness, OID_AUTO, free_cnt, CTLFLAG_RD, &w_free_cnt, 0, ""); 249SYSCTL_INT(_debug_witness, OID_AUTO, spin_cnt, CTLFLAG_RD, &w_spin_cnt, 0, ""); 250SYSCTL_INT(_debug_witness, OID_AUTO, sleep_cnt, CTLFLAG_RD, &w_sleep_cnt, 0, 251 ""); 252SYSCTL_INT(_debug_witness, OID_AUTO, child_free_cnt, CTLFLAG_RD, 253 &w_child_free_cnt, 0, ""); 254SYSCTL_INT(_debug_witness, OID_AUTO, child_cnt, CTLFLAG_RD, &w_child_cnt, 0, 255 ""); 256 257static struct witness w_data[WITNESS_COUNT]; 258static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 259static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 260 261static struct witness_order_list_entry order_lists[] = { 262 /* 263 * sx locks 264 */ 265 { "proctree", &lock_class_sx }, 266 { "allproc", &lock_class_sx }, 267 { NULL, NULL }, 268 /* 269 * Various mutexes 270 */ 271 { "Giant", &lock_class_mtx_sleep }, 272 { "filedesc structure", &lock_class_mtx_sleep }, 273 { "pipe mutex", &lock_class_mtx_sleep }, 274 { "sigio lock", &lock_class_mtx_sleep }, 275 { "process group", &lock_class_mtx_sleep }, 276 { "process lock", &lock_class_mtx_sleep }, 277 { "session", &lock_class_mtx_sleep }, 278 { "uidinfo hash", &lock_class_mtx_sleep }, 279 { "uidinfo struct", &lock_class_mtx_sleep }, 280 { "allprison", &lock_class_mtx_sleep }, 281 { NULL, NULL }, 282 /* 283 * Sockets 284 */ 285 { "filedesc structure", &lock_class_mtx_sleep }, 286 { "accept", &lock_class_mtx_sleep }, 287 { "so_snd", &lock_class_mtx_sleep }, 288 { "so_rcv", &lock_class_mtx_sleep }, 289 { "sellck", &lock_class_mtx_sleep }, 290 { NULL, NULL }, 291 /* 292 * Routing 293 */ 294 { "so_rcv", &lock_class_mtx_sleep }, 295 { "radix node head", &lock_class_mtx_sleep }, 296 { "rtentry", &lock_class_mtx_sleep }, 297 { "ifaddr", &lock_class_mtx_sleep }, 298 { NULL, NULL }, 299 /* 300 * Multicast - protocol locks before interface locks, after UDP locks. 301 */ 302 { "udpinp", &lock_class_mtx_sleep }, 303 { "in_multi_mtx", &lock_class_mtx_sleep }, 304 { "igmp_mtx", &lock_class_mtx_sleep }, 305 { "if_addr_mtx", &lock_class_mtx_sleep }, 306 { NULL, NULL }, 307 /* 308 * UNIX Domain Sockets 309 */ 310 { "unp", &lock_class_mtx_sleep }, 311 { "so_snd", &lock_class_mtx_sleep }, 312 { NULL, NULL }, 313 /* 314 * UDP/IP 315 */ 316 { "udp", &lock_class_mtx_sleep }, 317 { "udpinp", &lock_class_mtx_sleep }, 318 { "so_snd", &lock_class_mtx_sleep }, 319 { NULL, NULL }, 320 /* 321 * TCP/IP 322 */ 323 { "tcp", &lock_class_mtx_sleep }, 324 { "tcpinp", &lock_class_mtx_sleep }, 325 { "so_snd", &lock_class_mtx_sleep }, 326 { NULL, NULL }, 327 /* 328 * SLIP 329 */ 330 { "slip_mtx", &lock_class_mtx_sleep }, 331 { "slip sc_mtx", &lock_class_mtx_sleep }, 332 { NULL, NULL }, 333 /* 334 * netatalk 335 */ 336 { "ddp_list_mtx", &lock_class_mtx_sleep }, 337 { "ddp_mtx", &lock_class_mtx_sleep }, 338 { NULL, NULL }, 339 /* 340 * BPF 341 */ 342 { "bpf global lock", &lock_class_mtx_sleep }, 343 { "bpf interface lock", &lock_class_mtx_sleep }, 344 { "bpf cdev lock", &lock_class_mtx_sleep }, 345 { NULL, NULL }, 346 /* 347 * NFS server 348 */ 349 { "nfsd_mtx", &lock_class_mtx_sleep }, 350 { "so_snd", &lock_class_mtx_sleep }, 351 { NULL, NULL }, 352 /* 353 * CDEV 354 */ 355 { "system map", &lock_class_mtx_sleep }, 356 { "vm page queue mutex", &lock_class_mtx_sleep }, 357 { "vnode interlock", &lock_class_mtx_sleep }, 358 { "cdev", &lock_class_mtx_sleep }, 359 { NULL, NULL }, 360 /* 361 * spin locks 362 */ 363#ifdef SMP 364 { "ap boot", &lock_class_mtx_spin }, 365#endif 366 { "sio", &lock_class_mtx_spin }, 367#ifdef __i386__ 368 { "cy", &lock_class_mtx_spin }, 369#endif 370 { "uart_hwmtx", &lock_class_mtx_spin }, 371 { "sabtty", &lock_class_mtx_spin }, 372 { "zstty", &lock_class_mtx_spin }, 373 { "ng_node", &lock_class_mtx_spin }, 374 { "ng_worklist", &lock_class_mtx_spin }, 375 { "taskqueue_fast", &lock_class_mtx_spin }, 376 { "intr table", &lock_class_mtx_spin }, 377 { "ithread table lock", &lock_class_mtx_spin }, 378 { "sleepq chain", &lock_class_mtx_spin }, 379 { "sched lock", &lock_class_mtx_spin }, 380 { "turnstile chain", &lock_class_mtx_spin }, 381 { "td_contested", &lock_class_mtx_spin }, 382 { "callout", &lock_class_mtx_spin }, 383 { "entropy harvest mutex", &lock_class_mtx_spin }, 384 /* 385 * leaf locks 386 */ 387 { "allpmaps", &lock_class_mtx_spin }, 388 { "vm page queue free mutex", &lock_class_mtx_spin }, 389 { "icu", &lock_class_mtx_spin }, 390#ifdef SMP 391 { "smp rendezvous", &lock_class_mtx_spin }, 392#if defined(__i386__) || defined(__amd64__) 393 { "tlb", &lock_class_mtx_spin }, 394#endif 395#ifdef __sparc64__ 396 { "ipi", &lock_class_mtx_spin }, 397 { "rtc_mtx", &lock_class_mtx_spin }, 398#endif 399#endif 400 { "clk", &lock_class_mtx_spin }, 401 { "mutex profiling lock", &lock_class_mtx_spin }, 402 { "kse zombie lock", &lock_class_mtx_spin }, 403 { "ALD Queue", &lock_class_mtx_spin }, 404#ifdef __ia64__ 405 { "MCA spin lock", &lock_class_mtx_spin }, 406#endif 407#if defined(__i386__) || defined(__amd64__) 408 { "pcicfg", &lock_class_mtx_spin }, 409 { "NDIS thread lock", &lock_class_mtx_spin }, 410#endif 411 { "tw_osl_io_lock", &lock_class_mtx_spin }, 412 { "tw_osl_q_lock", &lock_class_mtx_spin }, 413 { "tw_cl_io_lock", &lock_class_mtx_spin }, 414 { "tw_cl_intr_lock", &lock_class_mtx_spin }, 415 { "tw_cl_gen_lock", &lock_class_mtx_spin }, 416 { NULL, NULL }, 417 { NULL, NULL } 418}; 419 420#ifdef BLESSING 421/* 422 * Pairs of locks which have been blessed 423 * Don't complain about order problems with blessed locks 424 */ 425static struct witness_blessed blessed_list[] = { 426}; 427static int blessed_count = 428 sizeof(blessed_list) / sizeof(struct witness_blessed); 429#endif 430 431/* 432 * List of all locks in the system. 433 */ 434TAILQ_HEAD(, lock_object) all_locks = TAILQ_HEAD_INITIALIZER(all_locks); 435 436static struct mtx all_mtx = { 437 { &lock_class_mtx_sleep, /* mtx_object.lo_class */ 438 "All locks list", /* mtx_object.lo_name */ 439 "All locks list", /* mtx_object.lo_type */ 440 LO_INITIALIZED, /* mtx_object.lo_flags */ 441 { NULL, NULL }, /* mtx_object.lo_list */ 442 NULL }, /* mtx_object.lo_witness */ 443 MTX_UNOWNED, 0 /* mtx_lock, mtx_recurse */ 444}; 445 446/* 447 * This global is set to 0 once it becomes safe to use the witness code. 448 */ 449static int witness_cold = 1; 450 451/* 452 * Global variables for book keeping. 453 */ 454static int lock_cur_cnt; 455static int lock_max_cnt; 456 457/* 458 * The WITNESS-enabled diagnostic code. 459 */ 460static void 461witness_initialize(void *dummy __unused) 462{ 463 struct lock_object *lock; 464 struct witness_order_list_entry *order; 465 struct witness *w, *w1; 466 int i; 467 468 /* 469 * We have to release Giant before initializing its witness 470 * structure so that WITNESS doesn't get confused. 471 */ 472 mtx_unlock(&Giant); 473 mtx_assert(&Giant, MA_NOTOWNED); 474 475 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 476 TAILQ_INSERT_HEAD(&all_locks, &all_mtx.mtx_object, lo_list); 477 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 478 MTX_NOWITNESS); 479 for (i = 0; i < WITNESS_COUNT; i++) 480 witness_free(&w_data[i]); 481 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 482 witness_child_free(&w_childdata[i]); 483 for (i = 0; i < LOCK_CHILDCOUNT; i++) 484 witness_lock_list_free(&w_locklistdata[i]); 485 486 /* First add in all the specified order lists. */ 487 for (order = order_lists; order->w_name != NULL; order++) { 488 w = enroll(order->w_name, order->w_class); 489 if (w == NULL) 490 continue; 491 w->w_file = "order list"; 492 for (order++; order->w_name != NULL; order++) { 493 w1 = enroll(order->w_name, order->w_class); 494 if (w1 == NULL) 495 continue; 496 w1->w_file = "order list"; 497 if (!itismychild(w, w1)) 498 panic("Not enough memory for static orders!"); 499 w = w1; 500 } 501 } 502 503 /* Iterate through all locks and add them to witness. */ 504 mtx_lock(&all_mtx); 505 TAILQ_FOREACH(lock, &all_locks, lo_list) { 506 if (lock->lo_flags & LO_WITNESS) 507 lock->lo_witness = enroll(lock->lo_type, 508 lock->lo_class); 509 else 510 lock->lo_witness = NULL; 511 } 512 mtx_unlock(&all_mtx); 513 514 /* Mark the witness code as being ready for use. */ 515 atomic_store_rel_int(&witness_cold, 0); 516 517 mtx_lock(&Giant); 518} 519SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, NULL) 520 521static int 522sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS) 523{ 524 int error, value; 525 526 value = witness_watch; 527 error = sysctl_handle_int(oidp, &value, 0, req); 528 if (error != 0 || req->newptr == NULL) 529 return (error); 530 error = suser(req->td); 531 if (error != 0) 532 return (error); 533 if (value == witness_watch) 534 return (0); 535 if (value != 0) 536 return (EINVAL); 537 witness_watch = 0; 538 return (0); 539} 540 541void 542witness_init(struct lock_object *lock) 543{ 544 struct lock_class *class; 545 546 class = lock->lo_class; 547 if (lock->lo_flags & LO_INITIALIZED) 548 panic("%s: lock (%s) %s is already initialized", __func__, 549 class->lc_name, lock->lo_name); 550 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 551 (class->lc_flags & LC_RECURSABLE) == 0) 552 panic("%s: lock (%s) %s can not be recursable", __func__, 553 class->lc_name, lock->lo_name); 554 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 555 (class->lc_flags & LC_SLEEPABLE) == 0) 556 panic("%s: lock (%s) %s can not be sleepable", __func__, 557 class->lc_name, lock->lo_name); 558 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 559 (class->lc_flags & LC_UPGRADABLE) == 0) 560 panic("%s: lock (%s) %s can not be upgradable", __func__, 561 class->lc_name, lock->lo_name); 562 563 mtx_lock(&all_mtx); 564 TAILQ_INSERT_TAIL(&all_locks, lock, lo_list); 565 lock->lo_flags |= LO_INITIALIZED; 566 lock_cur_cnt++; 567 if (lock_cur_cnt > lock_max_cnt) 568 lock_max_cnt = lock_cur_cnt; 569 mtx_unlock(&all_mtx); 570 if (!witness_cold && witness_watch != 0 && panicstr == NULL && 571 (lock->lo_flags & LO_WITNESS) != 0) 572 lock->lo_witness = enroll(lock->lo_type, class); 573 else 574 lock->lo_witness = NULL; 575} 576 577void 578witness_destroy(struct lock_object *lock) 579{ 580 struct witness *w; 581 582 if (witness_cold) 583 panic("lock (%s) %s destroyed while witness_cold", 584 lock->lo_class->lc_name, lock->lo_name); 585 if ((lock->lo_flags & LO_INITIALIZED) == 0) 586 panic("%s: lock (%s) %s is not initialized", __func__, 587 lock->lo_class->lc_name, lock->lo_name); 588 589 /* XXX: need to verify that no one holds the lock */ 590 w = lock->lo_witness; 591 if (w != NULL) { 592 mtx_lock_spin(&w_mtx); 593 MPASS(w->w_refcount > 0); 594 w->w_refcount--; 595 596 /* 597 * Lock is already released if we have an allocation failure 598 * and depart() fails. 599 */ 600 if (w->w_refcount != 0 || depart(w)) 601 mtx_unlock_spin(&w_mtx); 602 } 603 604 mtx_lock(&all_mtx); 605 lock_cur_cnt--; 606 TAILQ_REMOVE(&all_locks, lock, lo_list); 607 lock->lo_flags &= ~LO_INITIALIZED; 608 mtx_unlock(&all_mtx); 609} 610 611#ifdef DDB 612static void 613witness_display_list(void(*prnt)(const char *fmt, ...), 614 struct witness_list *list) 615{ 616 struct witness *w; 617 618 STAILQ_FOREACH(w, list, w_typelist) { 619 if (w->w_file == NULL || w->w_level > 0) 620 continue; 621 /* 622 * This lock has no anscestors, display its descendants. 623 */ 624 witness_displaydescendants(prnt, w, 0); 625 } 626} 627 628static void 629witness_display(void(*prnt)(const char *fmt, ...)) 630{ 631 struct witness *w; 632 633 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 634 witness_levelall(); 635 636 /* Clear all the displayed flags. */ 637 STAILQ_FOREACH(w, &w_all, w_list) { 638 w->w_displayed = 0; 639 } 640 641 /* 642 * First, handle sleep locks which have been acquired at least 643 * once. 644 */ 645 prnt("Sleep locks:\n"); 646 witness_display_list(prnt, &w_sleep); 647 648 /* 649 * Now do spin locks which have been acquired at least once. 650 */ 651 prnt("\nSpin locks:\n"); 652 witness_display_list(prnt, &w_spin); 653 654 /* 655 * Finally, any locks which have not been acquired yet. 656 */ 657 prnt("\nLocks which were never acquired:\n"); 658 STAILQ_FOREACH(w, &w_all, w_list) { 659 if (w->w_file != NULL || w->w_refcount == 0) 660 continue; 661 prnt("%s\n", w->w_name); 662 } 663} 664#endif /* DDB */ 665 666/* Trim useless garbage from filenames. */ 667static const char * 668fixup_filename(const char *file) 669{ 670 671 if (file == NULL) 672 return (NULL); 673 while (strncmp(file, "../", 3) == 0) 674 file += 3; 675 return (file); 676} 677 678int 679witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) 680{ 681 682 if (witness_watch == 0 || panicstr != NULL) 683 return (0); 684 685 /* Require locks that witness knows about. */ 686 if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || 687 lock2->lo_witness == NULL) 688 return (EINVAL); 689 690 MPASS(!mtx_owned(&w_mtx)); 691 mtx_lock_spin(&w_mtx); 692 693 /* 694 * If we already have either an explicit or implied lock order that 695 * is the other way around, then return an error. 696 */ 697 if (isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { 698 mtx_unlock_spin(&w_mtx); 699 return (EDOOFUS); 700 } 701 702 /* Try to add the new order. */ 703 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 704 lock2->lo_type, lock1->lo_type); 705 if (!itismychild(lock1->lo_witness, lock2->lo_witness)) 706 return (ENOMEM); 707 mtx_unlock_spin(&w_mtx); 708 return (0); 709} 710 711void 712witness_checkorder(struct lock_object *lock, int flags, const char *file, 713 int line) 714{ 715 struct lock_list_entry **lock_list, *lle; 716 struct lock_instance *lock1, *lock2; 717 struct lock_class *class; 718 struct witness *w, *w1; 719 struct thread *td; 720 int i, j; 721 722 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 723 panicstr != NULL) 724 return; 725 726 /* 727 * Try locks do not block if they fail to acquire the lock, thus 728 * there is no danger of deadlocks or of switching while holding a 729 * spin lock if we acquire a lock via a try operation. This 730 * function shouldn't even be called for try locks, so panic if 731 * that happens. 732 */ 733 if (flags & LOP_TRYLOCK) 734 panic("%s should not be called for try lock operations", 735 __func__); 736 737 w = lock->lo_witness; 738 class = lock->lo_class; 739 td = curthread; 740 file = fixup_filename(file); 741 742 if (class->lc_flags & LC_SLEEPLOCK) { 743 /* 744 * Since spin locks include a critical section, this check 745 * implicitly enforces a lock order of all sleep locks before 746 * all spin locks. 747 */ 748 if (td->td_critnest != 0 && !kdb_active) 749 panic("blockable sleep lock (%s) %s @ %s:%d", 750 class->lc_name, lock->lo_name, file, line); 751 752 /* 753 * If this is the first lock acquired then just return as 754 * no order checking is needed. 755 */ 756 if (td->td_sleeplocks == NULL) 757 return; 758 lock_list = &td->td_sleeplocks; 759 } else { 760 /* 761 * If this is the first lock, just return as no order 762 * checking is needed. We check this in both if clauses 763 * here as unifying the check would require us to use a 764 * critical section to ensure we don't migrate while doing 765 * the check. Note that if this is not the first lock, we 766 * are already in a critical section and are safe for the 767 * rest of the check. 768 */ 769 if (PCPU_GET(spinlocks) == NULL) 770 return; 771 lock_list = PCPU_PTR(spinlocks); 772 } 773 774 /* 775 * Check to see if we are recursing on a lock we already own. If 776 * so, make sure that we don't mismatch exclusive and shared lock 777 * acquires. 778 */ 779 lock1 = find_instance(*lock_list, lock); 780 if (lock1 != NULL) { 781 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 782 (flags & LOP_EXCLUSIVE) == 0) { 783 printf("shared lock of (%s) %s @ %s:%d\n", 784 class->lc_name, lock->lo_name, file, line); 785 printf("while exclusively locked from %s:%d\n", 786 lock1->li_file, lock1->li_line); 787 panic("share->excl"); 788 } 789 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 790 (flags & LOP_EXCLUSIVE) != 0) { 791 printf("exclusive lock of (%s) %s @ %s:%d\n", 792 class->lc_name, lock->lo_name, file, line); 793 printf("while share locked from %s:%d\n", 794 lock1->li_file, lock1->li_line); 795 panic("excl->share"); 796 } 797 return; 798 } 799 800 /* 801 * Try locks do not block if they fail to acquire the lock, thus 802 * there is no danger of deadlocks or of switching while holding a 803 * spin lock if we acquire a lock via a try operation. 804 */ 805 if (flags & LOP_TRYLOCK) 806 return; 807 808 /* 809 * Check for duplicate locks of the same type. Note that we only 810 * have to check for this on the last lock we just acquired. Any 811 * other cases will be caught as lock order violations. 812 */ 813 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 814 w1 = lock1->li_lock->lo_witness; 815 if (w1 == w) { 816 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK) || 817 (flags & LOP_DUPOK)) 818 return; 819 w->w_same_squawked = 1; 820 printf("acquiring duplicate lock of same type: \"%s\"\n", 821 lock->lo_type); 822 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 823 lock1->li_file, lock1->li_line); 824 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 825#ifdef KDB 826 goto debugger; 827#else 828 return; 829#endif 830 } 831 MPASS(!mtx_owned(&w_mtx)); 832 mtx_lock_spin(&w_mtx); 833 /* 834 * If we know that the the lock we are acquiring comes after 835 * the lock we most recently acquired in the lock order tree, 836 * then there is no need for any further checks. 837 */ 838 if (isitmychild(w1, w)) { 839 mtx_unlock_spin(&w_mtx); 840 return; 841 } 842 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 843 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 844 845 MPASS(j < WITNESS_COUNT); 846 lock1 = &lle->ll_children[i]; 847 w1 = lock1->li_lock->lo_witness; 848 849 /* 850 * If this lock doesn't undergo witness checking, 851 * then skip it. 852 */ 853 if (w1 == NULL) { 854 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 855 ("lock missing witness structure")); 856 continue; 857 } 858 /* 859 * If we are locking Giant and this is a sleepable 860 * lock, then skip it. 861 */ 862 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && 863 lock == &Giant.mtx_object) 864 continue; 865 /* 866 * If we are locking a sleepable lock and this lock 867 * is Giant, then skip it. 868 */ 869 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 870 lock1->li_lock == &Giant.mtx_object) 871 continue; 872 /* 873 * If we are locking a sleepable lock and this lock 874 * isn't sleepable, we want to treat it as a lock 875 * order violation to enfore a general lock order of 876 * sleepable locks before non-sleepable locks. 877 */ 878 if (((lock->lo_flags & LO_SLEEPABLE) != 0 && 879 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 880 goto reversal; 881 /* 882 * Check the lock order hierarchy for a reveresal. 883 */ 884 if (!isitmydescendant(w, w1)) 885 continue; 886 reversal: 887 /* 888 * We have a lock order violation, check to see if it 889 * is allowed or has already been yelled about. 890 */ 891 mtx_unlock_spin(&w_mtx); 892#ifdef BLESSING 893 /* 894 * If the lock order is blessed, just bail. We don't 895 * look for other lock order violations though, which 896 * may be a bug. 897 */ 898 if (blessed(w, w1)) 899 return; 900#endif 901 if (lock1->li_lock == &Giant.mtx_object) { 902 if (w1->w_Giant_squawked) 903 return; 904 else 905 w1->w_Giant_squawked = 1; 906 } else { 907 if (w1->w_other_squawked) 908 return; 909 else 910 w1->w_other_squawked = 1; 911 } 912 /* 913 * Ok, yell about it. 914 */ 915 printf("lock order reversal\n"); 916 /* 917 * Try to locate an earlier lock with 918 * witness w in our list. 919 */ 920 do { 921 lock2 = &lle->ll_children[i]; 922 MPASS(lock2->li_lock != NULL); 923 if (lock2->li_lock->lo_witness == w) 924 break; 925 if (i == 0 && lle->ll_next != NULL) { 926 lle = lle->ll_next; 927 i = lle->ll_count - 1; 928 MPASS(i >= 0 && i < LOCK_NCHILDREN); 929 } else 930 i--; 931 } while (i >= 0); 932 if (i < 0) { 933 printf(" 1st %p %s (%s) @ %s:%d\n", 934 lock1->li_lock, lock1->li_lock->lo_name, 935 lock1->li_lock->lo_type, lock1->li_file, 936 lock1->li_line); 937 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 938 lock->lo_name, lock->lo_type, file, line); 939 } else { 940 printf(" 1st %p %s (%s) @ %s:%d\n", 941 lock2->li_lock, lock2->li_lock->lo_name, 942 lock2->li_lock->lo_type, lock2->li_file, 943 lock2->li_line); 944 printf(" 2nd %p %s (%s) @ %s:%d\n", 945 lock1->li_lock, lock1->li_lock->lo_name, 946 lock1->li_lock->lo_type, lock1->li_file, 947 lock1->li_line); 948 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 949 lock->lo_name, lock->lo_type, file, line); 950 } 951#ifdef KDB 952 goto debugger; 953#else 954 return; 955#endif 956 } 957 } 958 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 959 /* 960 * If requested, build a new lock order. However, don't build a new 961 * relationship between a sleepable lock and Giant if it is in the 962 * wrong direction. The correct lock order is that sleepable locks 963 * always come before Giant. 964 */ 965 if (flags & LOP_NEWORDER && 966 !(lock1->li_lock == &Giant.mtx_object && 967 (lock->lo_flags & LO_SLEEPABLE) != 0)) { 968 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 969 lock->lo_type, lock1->li_lock->lo_type); 970 if (!itismychild(lock1->li_lock->lo_witness, w)) 971 /* Witness is dead. */ 972 return; 973 } 974 mtx_unlock_spin(&w_mtx); 975 return; 976 977#ifdef KDB 978debugger: 979 if (witness_trace) 980 kdb_backtrace(); 981 if (witness_kdb) 982 kdb_enter(__func__); 983#endif 984} 985 986void 987witness_lock(struct lock_object *lock, int flags, const char *file, int line) 988{ 989 struct lock_list_entry **lock_list, *lle; 990 struct lock_instance *instance; 991 struct witness *w; 992 struct thread *td; 993 994 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 995 panicstr != NULL) 996 return; 997 w = lock->lo_witness; 998 td = curthread; 999 file = fixup_filename(file); 1000 1001 /* Determine lock list for this lock. */ 1002 if (lock->lo_class->lc_flags & LC_SLEEPLOCK) 1003 lock_list = &td->td_sleeplocks; 1004 else 1005 lock_list = PCPU_PTR(spinlocks); 1006 1007 /* Check to see if we are recursing on a lock we already own. */ 1008 instance = find_instance(*lock_list, lock); 1009 if (instance != NULL) { 1010 instance->li_flags++; 1011 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 1012 td->td_proc->p_pid, lock->lo_name, 1013 instance->li_flags & LI_RECURSEMASK); 1014 instance->li_file = file; 1015 instance->li_line = line; 1016 return; 1017 } 1018 1019 /* Update per-witness last file and line acquire. */ 1020 w->w_file = file; 1021 w->w_line = line; 1022 1023 /* Find the next open lock instance in the list and fill it. */ 1024 lle = *lock_list; 1025 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 1026 lle = witness_lock_list_get(); 1027 if (lle == NULL) 1028 return; 1029 lle->ll_next = *lock_list; 1030 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 1031 td->td_proc->p_pid, lle); 1032 *lock_list = lle; 1033 } 1034 instance = &lle->ll_children[lle->ll_count++]; 1035 instance->li_lock = lock; 1036 instance->li_line = line; 1037 instance->li_file = file; 1038 if ((flags & LOP_EXCLUSIVE) != 0) 1039 instance->li_flags = LI_EXCLUSIVE; 1040 else 1041 instance->li_flags = 0; 1042 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 1043 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 1044} 1045 1046void 1047witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 1048{ 1049 struct lock_instance *instance; 1050 struct lock_class *class; 1051 1052 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1053 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1054 return; 1055 class = lock->lo_class; 1056 file = fixup_filename(file); 1057 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1058 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 1059 class->lc_name, lock->lo_name, file, line); 1060 if ((flags & LOP_TRYLOCK) == 0) 1061 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 1062 lock->lo_name, file, line); 1063 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1064 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 1065 class->lc_name, lock->lo_name, file, line); 1066 instance = find_instance(curthread->td_sleeplocks, lock); 1067 if (instance == NULL) 1068 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 1069 class->lc_name, lock->lo_name, file, line); 1070 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 1071 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 1072 class->lc_name, lock->lo_name, file, line); 1073 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1074 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 1075 class->lc_name, lock->lo_name, 1076 instance->li_flags & LI_RECURSEMASK, file, line); 1077 instance->li_flags |= LI_EXCLUSIVE; 1078} 1079 1080void 1081witness_downgrade(struct lock_object *lock, int flags, const char *file, 1082 int line) 1083{ 1084 struct lock_instance *instance; 1085 struct lock_class *class; 1086 1087 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1088 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1089 return; 1090 class = lock->lo_class; 1091 file = fixup_filename(file); 1092 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1093 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 1094 class->lc_name, lock->lo_name, file, line); 1095 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1096 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 1097 class->lc_name, lock->lo_name, file, line); 1098 instance = find_instance(curthread->td_sleeplocks, lock); 1099 if (instance == NULL) 1100 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 1101 class->lc_name, lock->lo_name, file, line); 1102 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 1103 panic("downgrade of shared lock (%s) %s @ %s:%d", 1104 class->lc_name, lock->lo_name, file, line); 1105 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1106 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 1107 class->lc_name, lock->lo_name, 1108 instance->li_flags & LI_RECURSEMASK, file, line); 1109 instance->li_flags &= ~LI_EXCLUSIVE; 1110} 1111 1112void 1113witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 1114{ 1115 struct lock_list_entry **lock_list, *lle; 1116 struct lock_instance *instance; 1117 struct lock_class *class; 1118 struct thread *td; 1119 register_t s; 1120 int i, j; 1121 1122 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1123 panicstr != NULL) 1124 return; 1125 td = curthread; 1126 class = lock->lo_class; 1127 file = fixup_filename(file); 1128 1129 /* Find lock instance associated with this lock. */ 1130 if (class->lc_flags & LC_SLEEPLOCK) 1131 lock_list = &td->td_sleeplocks; 1132 else 1133 lock_list = PCPU_PTR(spinlocks); 1134 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 1135 for (i = 0; i < (*lock_list)->ll_count; i++) { 1136 instance = &(*lock_list)->ll_children[i]; 1137 if (instance->li_lock == lock) 1138 goto found; 1139 } 1140 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 1141 file, line); 1142found: 1143 1144 /* First, check for shared/exclusive mismatches. */ 1145 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 1146 (flags & LOP_EXCLUSIVE) == 0) { 1147 printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name, 1148 lock->lo_name, file, line); 1149 printf("while exclusively locked from %s:%d\n", 1150 instance->li_file, instance->li_line); 1151 panic("excl->ushare"); 1152 } 1153 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 1154 (flags & LOP_EXCLUSIVE) != 0) { 1155 printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name, 1156 lock->lo_name, file, line); 1157 printf("while share locked from %s:%d\n", instance->li_file, 1158 instance->li_line); 1159 panic("share->uexcl"); 1160 } 1161 1162 /* If we are recursed, unrecurse. */ 1163 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 1164 CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, 1165 td->td_proc->p_pid, instance->li_lock->lo_name, 1166 instance->li_flags); 1167 instance->li_flags--; 1168 return; 1169 } 1170 1171 /* Otherwise, remove this item from the list. */ 1172 s = intr_disable(); 1173 CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, 1174 td->td_proc->p_pid, instance->li_lock->lo_name, 1175 (*lock_list)->ll_count - 1); 1176 for (j = i; j < (*lock_list)->ll_count - 1; j++) 1177 (*lock_list)->ll_children[j] = 1178 (*lock_list)->ll_children[j + 1]; 1179 (*lock_list)->ll_count--; 1180 intr_restore(s); 1181 1182 /* If this lock list entry is now empty, free it. */ 1183 if ((*lock_list)->ll_count == 0) { 1184 lle = *lock_list; 1185 *lock_list = lle->ll_next; 1186 CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, 1187 td->td_proc->p_pid, lle); 1188 witness_lock_list_free(lle); 1189 } 1190} 1191 1192/* 1193 * Warn if any locks other than 'lock' are held. Flags can be passed in to 1194 * exempt Giant and sleepable locks from the checks as well. If any 1195 * non-exempt locks are held, then a supplied message is printed to the 1196 * console along with a list of the offending locks. If indicated in the 1197 * flags then a failure results in a panic as well. 1198 */ 1199int 1200witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) 1201{ 1202 struct lock_list_entry *lle; 1203 struct lock_instance *lock1; 1204 struct thread *td; 1205 va_list ap; 1206 int i, n; 1207 1208 if (witness_cold || witness_watch == 0 || panicstr != NULL) 1209 return (0); 1210 n = 0; 1211 td = curthread; 1212 for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next) 1213 for (i = lle->ll_count - 1; i >= 0; i--) { 1214 lock1 = &lle->ll_children[i]; 1215 if (lock1->li_lock == lock) 1216 continue; 1217 if (flags & WARN_GIANTOK && 1218 lock1->li_lock == &Giant.mtx_object) 1219 continue; 1220 if (flags & WARN_SLEEPOK && 1221 (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) 1222 continue; 1223 if (n == 0) { 1224 va_start(ap, fmt); 1225 vprintf(fmt, ap); 1226 va_end(ap); 1227 printf(" with the following"); 1228 if (flags & WARN_SLEEPOK) 1229 printf(" non-sleepable"); 1230 printf(" locks held:\n"); 1231 } 1232 n++; 1233 witness_list_lock(lock1); 1234 } 1235 if (PCPU_GET(spinlocks) != NULL) { 1236 /* 1237 * Since we already hold a spinlock preemption is 1238 * already blocked. 1239 */ 1240 if (n == 0) { 1241 va_start(ap, fmt); 1242 vprintf(fmt, ap); 1243 va_end(ap); 1244 printf(" with the following"); 1245 if (flags & WARN_SLEEPOK) 1246 printf(" non-sleepable"); 1247 printf(" locks held:\n"); 1248 } 1249 n += witness_list_locks(PCPU_PTR(spinlocks)); 1250 } 1251 if (flags & WARN_PANIC && n) 1252 panic("witness_warn"); 1253#ifdef KDB 1254 else if (witness_kdb && n) 1255 kdb_enter(__func__); 1256 else if (witness_trace && n) 1257 kdb_backtrace(); 1258#endif 1259 return (n); 1260} 1261 1262const char * 1263witness_file(struct lock_object *lock) 1264{ 1265 struct witness *w; 1266 1267 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1268 return ("?"); 1269 w = lock->lo_witness; 1270 return (w->w_file); 1271} 1272 1273int 1274witness_line(struct lock_object *lock) 1275{ 1276 struct witness *w; 1277 1278 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1279 return (0); 1280 w = lock->lo_witness; 1281 return (w->w_line); 1282} 1283 1284static struct witness * 1285enroll(const char *description, struct lock_class *lock_class) 1286{ 1287 struct witness *w; 1288 1289 if (witness_watch == 0 || panicstr != NULL) 1290 return (NULL); 1291 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 1292 return (NULL); 1293 mtx_lock_spin(&w_mtx); 1294 STAILQ_FOREACH(w, &w_all, w_list) { 1295 if (w->w_name == description || (w->w_refcount > 0 && 1296 strcmp(description, w->w_name) == 0)) { 1297 w->w_refcount++; 1298 mtx_unlock_spin(&w_mtx); 1299 if (lock_class != w->w_class) 1300 panic( 1301 "lock (%s) %s does not match earlier (%s) lock", 1302 description, lock_class->lc_name, 1303 w->w_class->lc_name); 1304 return (w); 1305 } 1306 } 1307 /* 1308 * This isn't quite right, as witness_cold is still 0 while we 1309 * enroll all the locks initialized before witness_initialize(). 1310 */ 1311 if ((lock_class->lc_flags & LC_SPINLOCK) && !witness_cold) { 1312 mtx_unlock_spin(&w_mtx); 1313 panic("spin lock %s not in order list", description); 1314 } 1315 if ((w = witness_get()) == NULL) 1316 return (NULL); 1317 w->w_name = description; 1318 w->w_class = lock_class; 1319 w->w_refcount = 1; 1320 STAILQ_INSERT_HEAD(&w_all, w, w_list); 1321 if (lock_class->lc_flags & LC_SPINLOCK) { 1322 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 1323 w_spin_cnt++; 1324 } else if (lock_class->lc_flags & LC_SLEEPLOCK) { 1325 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 1326 w_sleep_cnt++; 1327 } else { 1328 mtx_unlock_spin(&w_mtx); 1329 panic("lock class %s is not sleep or spin", 1330 lock_class->lc_name); 1331 } 1332 mtx_unlock_spin(&w_mtx); 1333 return (w); 1334} 1335 1336/* Don't let the door bang you on the way out... */ 1337static int 1338depart(struct witness *w) 1339{ 1340 struct witness_child_list_entry *wcl, *nwcl; 1341 struct witness_list *list; 1342 struct witness *parent; 1343 1344 MPASS(w->w_refcount == 0); 1345 if (w->w_class->lc_flags & LC_SLEEPLOCK) { 1346 list = &w_sleep; 1347 w_sleep_cnt--; 1348 } else { 1349 list = &w_spin; 1350 w_spin_cnt--; 1351 } 1352 /* 1353 * First, we run through the entire tree looking for any 1354 * witnesses that the outgoing witness is a child of. For 1355 * each parent that we find, we reparent all the direct 1356 * children of the outgoing witness to its parent. 1357 */ 1358 STAILQ_FOREACH(parent, list, w_typelist) { 1359 if (!isitmychild(parent, w)) 1360 continue; 1361 removechild(parent, w); 1362 } 1363 1364 /* 1365 * Now we go through and free up the child list of the 1366 * outgoing witness. 1367 */ 1368 for (wcl = w->w_children; wcl != NULL; wcl = nwcl) { 1369 nwcl = wcl->wcl_next; 1370 w_child_cnt--; 1371 witness_child_free(wcl); 1372 } 1373 1374 /* 1375 * Detach from various lists and free. 1376 */ 1377 STAILQ_REMOVE(list, w, witness, w_typelist); 1378 STAILQ_REMOVE(&w_all, w, witness, w_list); 1379 witness_free(w); 1380 1381 return (1); 1382} 1383 1384/* 1385 * Add "child" as a direct child of "parent". Returns false if 1386 * we fail due to out of memory. 1387 */ 1388static int 1389insertchild(struct witness *parent, struct witness *child) 1390{ 1391 struct witness_child_list_entry **wcl; 1392 1393 MPASS(child != NULL && parent != NULL); 1394 1395 /* 1396 * Insert "child" after "parent" 1397 */ 1398 wcl = &parent->w_children; 1399 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1400 wcl = &(*wcl)->wcl_next; 1401 if (*wcl == NULL) { 1402 *wcl = witness_child_get(); 1403 if (*wcl == NULL) 1404 return (0); 1405 w_child_cnt++; 1406 } 1407 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1408 1409 return (1); 1410} 1411 1412 1413static int 1414itismychild(struct witness *parent, struct witness *child) 1415{ 1416 struct witness_list *list; 1417 1418 MPASS(child != NULL && parent != NULL); 1419 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 1420 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 1421 panic( 1422 "%s: parent (%s) and child (%s) are not the same lock type", 1423 __func__, parent->w_class->lc_name, 1424 child->w_class->lc_name); 1425 1426 if (!insertchild(parent, child)) 1427 return (0); 1428 1429 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1430 list = &w_sleep; 1431 else 1432 list = &w_spin; 1433 return (1); 1434} 1435 1436static void 1437removechild(struct witness *parent, struct witness *child) 1438{ 1439 struct witness_child_list_entry **wcl, *wcl1; 1440 int i; 1441 1442 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1443 for (i = 0; i < (*wcl)->wcl_count; i++) 1444 if ((*wcl)->wcl_children[i] == child) 1445 goto found; 1446 return; 1447found: 1448 (*wcl)->wcl_count--; 1449 if ((*wcl)->wcl_count > i) 1450 (*wcl)->wcl_children[i] = 1451 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1452 MPASS((*wcl)->wcl_children[i] != NULL); 1453 if ((*wcl)->wcl_count != 0) 1454 return; 1455 wcl1 = *wcl; 1456 *wcl = wcl1->wcl_next; 1457 w_child_cnt--; 1458 witness_child_free(wcl1); 1459} 1460 1461static int 1462isitmychild(struct witness *parent, struct witness *child) 1463{ 1464 struct witness_child_list_entry *wcl; 1465 int i; 1466 1467 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1468 for (i = 0; i < wcl->wcl_count; i++) { 1469 if (wcl->wcl_children[i] == child) 1470 return (1); 1471 } 1472 } 1473 return (0); 1474} 1475 1476static int 1477isitmydescendant(struct witness *parent, struct witness *child) 1478{ 1479 struct witness_child_list_entry *wcl; 1480 int i, j; 1481 1482 if (isitmychild(parent, child)) 1483 return (1); 1484 j = 0; 1485 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1486 MPASS(j < 1000); 1487 for (i = 0; i < wcl->wcl_count; i++) { 1488 if (isitmydescendant(wcl->wcl_children[i], child)) 1489 return (1); 1490 } 1491 j++; 1492 } 1493 return (0); 1494} 1495 1496static void 1497witness_levelall (void) 1498{ 1499 struct witness_list *list; 1500 struct witness *w, *w1; 1501 1502 /* 1503 * First clear all levels. 1504 */ 1505 STAILQ_FOREACH(w, &w_all, w_list) { 1506 w->w_level = 0; 1507 } 1508 1509 /* 1510 * Look for locks with no parent and level all their descendants. 1511 */ 1512 STAILQ_FOREACH(w, &w_all, w_list) { 1513 /* 1514 * This is just an optimization, technically we could get 1515 * away just walking the all list each time. 1516 */ 1517 if (w->w_class->lc_flags & LC_SLEEPLOCK) 1518 list = &w_sleep; 1519 else 1520 list = &w_spin; 1521 STAILQ_FOREACH(w1, list, w_typelist) { 1522 if (isitmychild(w1, w)) 1523 goto skip; 1524 } 1525 witness_leveldescendents(w, 0); 1526 skip: 1527 ; /* silence GCC 3.x */ 1528 } 1529} 1530 1531static void 1532witness_leveldescendents(struct witness *parent, int level) 1533{ 1534 struct witness_child_list_entry *wcl; 1535 int i; 1536 1537 if (parent->w_level < level) 1538 parent->w_level = level; 1539 level++; 1540 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1541 for (i = 0; i < wcl->wcl_count; i++) 1542 witness_leveldescendents(wcl->wcl_children[i], level); 1543} 1544 1545static void 1546witness_displaydescendants(void(*prnt)(const char *fmt, ...), 1547 struct witness *parent, int indent) 1548{ 1549 struct witness_child_list_entry *wcl; 1550 int i, level; 1551 1552 level = parent->w_level; 1553 prnt("%-2d", level); 1554 for (i = 0; i < indent; i++) 1555 prnt(" "); 1556 if (parent->w_refcount > 0) 1557 prnt("%s", parent->w_name); 1558 else 1559 prnt("(dead)"); 1560 if (parent->w_displayed) { 1561 prnt(" -- (already displayed)\n"); 1562 return; 1563 } 1564 parent->w_displayed = 1; 1565 if (parent->w_refcount > 0) { 1566 if (parent->w_file != NULL) 1567 prnt(" -- last acquired @ %s:%d", parent->w_file, 1568 parent->w_line); 1569 } 1570 prnt("\n"); 1571 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 1572 for (i = 0; i < wcl->wcl_count; i++) 1573 witness_displaydescendants(prnt, 1574 wcl->wcl_children[i], indent + 1); 1575} 1576 1577#ifdef BLESSING 1578static int 1579blessed(struct witness *w1, struct witness *w2) 1580{ 1581 int i; 1582 struct witness_blessed *b; 1583 1584 for (i = 0; i < blessed_count; i++) { 1585 b = &blessed_list[i]; 1586 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1587 if (strcmp(w2->w_name, b->b_lock2) == 0) 1588 return (1); 1589 continue; 1590 } 1591 if (strcmp(w1->w_name, b->b_lock2) == 0) 1592 if (strcmp(w2->w_name, b->b_lock1) == 0) 1593 return (1); 1594 } 1595 return (0); 1596} 1597#endif 1598 1599static struct witness * 1600witness_get(void) 1601{ 1602 struct witness *w; 1603 1604 if (witness_watch == 0) { 1605 mtx_unlock_spin(&w_mtx); 1606 return (NULL); 1607 } 1608 if (STAILQ_EMPTY(&w_free)) { 1609 witness_watch = 0; 1610 mtx_unlock_spin(&w_mtx); 1611 printf("%s: witness exhausted\n", __func__); 1612 return (NULL); 1613 } 1614 w = STAILQ_FIRST(&w_free); 1615 STAILQ_REMOVE_HEAD(&w_free, w_list); 1616 w_free_cnt--; 1617 bzero(w, sizeof(*w)); 1618 return (w); 1619} 1620 1621static void 1622witness_free(struct witness *w) 1623{ 1624 1625 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1626 w_free_cnt++; 1627} 1628 1629static struct witness_child_list_entry * 1630witness_child_get(void) 1631{ 1632 struct witness_child_list_entry *wcl; 1633 1634 if (witness_watch == 0) { 1635 mtx_unlock_spin(&w_mtx); 1636 return (NULL); 1637 } 1638 wcl = w_child_free; 1639 if (wcl == NULL) { 1640 witness_watch = 0; 1641 mtx_unlock_spin(&w_mtx); 1642 printf("%s: witness exhausted\n", __func__); 1643 return (NULL); 1644 } 1645 w_child_free = wcl->wcl_next; 1646 w_child_free_cnt--; 1647 bzero(wcl, sizeof(*wcl)); 1648 return (wcl); 1649} 1650 1651static void 1652witness_child_free(struct witness_child_list_entry *wcl) 1653{ 1654 1655 wcl->wcl_next = w_child_free; 1656 w_child_free = wcl; 1657 w_child_free_cnt++; 1658} 1659 1660static struct lock_list_entry * 1661witness_lock_list_get(void) 1662{ 1663 struct lock_list_entry *lle; 1664 1665 if (witness_watch == 0) 1666 return (NULL); 1667 mtx_lock_spin(&w_mtx); 1668 lle = w_lock_list_free; 1669 if (lle == NULL) { 1670 witness_watch = 0; 1671 mtx_unlock_spin(&w_mtx); 1672 printf("%s: witness exhausted\n", __func__); 1673 return (NULL); 1674 } 1675 w_lock_list_free = lle->ll_next; 1676 mtx_unlock_spin(&w_mtx); 1677 bzero(lle, sizeof(*lle)); 1678 return (lle); 1679} 1680 1681static void 1682witness_lock_list_free(struct lock_list_entry *lle) 1683{ 1684 1685 mtx_lock_spin(&w_mtx); 1686 lle->ll_next = w_lock_list_free; 1687 w_lock_list_free = lle; 1688 mtx_unlock_spin(&w_mtx); 1689} 1690 1691static struct lock_instance * 1692find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1693{ 1694 struct lock_list_entry *lle; 1695 struct lock_instance *instance; 1696 int i; 1697 1698 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1699 for (i = lle->ll_count - 1; i >= 0; i--) { 1700 instance = &lle->ll_children[i]; 1701 if (instance->li_lock == lock) 1702 return (instance); 1703 } 1704 return (NULL); 1705} 1706 1707static void 1708witness_list_lock(struct lock_instance *instance) 1709{ 1710 struct lock_object *lock; 1711 1712 lock = instance->li_lock; 1713 printf("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1714 "exclusive" : "shared", lock->lo_class->lc_name, lock->lo_name); 1715 if (lock->lo_type != lock->lo_name) 1716 printf(" (%s)", lock->lo_type); 1717 printf(" r = %d (%p) locked @ %s:%d\n", 1718 instance->li_flags & LI_RECURSEMASK, lock, instance->li_file, 1719 instance->li_line); 1720} 1721 1722#ifdef DDB 1723static int 1724witness_thread_has_locks(struct thread *td) 1725{ 1726 1727 return (td->td_sleeplocks != NULL); 1728} 1729 1730static int 1731witness_proc_has_locks(struct proc *p) 1732{ 1733 struct thread *td; 1734 1735 FOREACH_THREAD_IN_PROC(p, td) { 1736 if (witness_thread_has_locks(td)) 1737 return (1); 1738 } 1739 return (0); 1740} 1741#endif 1742 1743int 1744witness_list_locks(struct lock_list_entry **lock_list) 1745{ 1746 struct lock_list_entry *lle; 1747 int i, nheld; 1748 1749 nheld = 0; 1750 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1751 for (i = lle->ll_count - 1; i >= 0; i--) { 1752 witness_list_lock(&lle->ll_children[i]); 1753 nheld++; 1754 } 1755 return (nheld); 1756} 1757 1758/* 1759 * This is a bit risky at best. We call this function when we have timed 1760 * out acquiring a spin lock, and we assume that the other CPU is stuck 1761 * with this lock held. So, we go groveling around in the other CPU's 1762 * per-cpu data to try to find the lock instance for this spin lock to 1763 * see when it was last acquired. 1764 */ 1765void 1766witness_display_spinlock(struct lock_object *lock, struct thread *owner) 1767{ 1768 struct lock_instance *instance; 1769 struct pcpu *pc; 1770 1771 if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU) 1772 return; 1773 pc = pcpu_find(owner->td_oncpu); 1774 instance = find_instance(pc->pc_spinlocks, lock); 1775 if (instance != NULL) 1776 witness_list_lock(instance); 1777} 1778 1779void 1780witness_save(struct lock_object *lock, const char **filep, int *linep) 1781{ 1782 struct lock_instance *instance; 1783 1784 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1785 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1786 return; 1787 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1788 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1789 lock->lo_class->lc_name, lock->lo_name); 1790 instance = find_instance(curthread->td_sleeplocks, lock); 1791 if (instance == NULL) 1792 panic("%s: lock (%s) %s not locked", __func__, 1793 lock->lo_class->lc_name, lock->lo_name); 1794 *filep = instance->li_file; 1795 *linep = instance->li_line; 1796} 1797 1798void 1799witness_restore(struct lock_object *lock, const char *file, int line) 1800{ 1801 struct lock_instance *instance; 1802 1803 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1804 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1805 return; 1806 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0) 1807 panic("%s: lock (%s) %s is not a sleep lock", __func__, 1808 lock->lo_class->lc_name, lock->lo_name); 1809 instance = find_instance(curthread->td_sleeplocks, lock); 1810 if (instance == NULL) 1811 panic("%s: lock (%s) %s not locked", __func__, 1812 lock->lo_class->lc_name, lock->lo_name); 1813 lock->lo_witness->w_file = file; 1814 lock->lo_witness->w_line = line; 1815 instance->li_file = file; 1816 instance->li_line = line; 1817} 1818 1819void 1820witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1821{ 1822#ifdef INVARIANT_SUPPORT 1823 struct lock_instance *instance; 1824 1825 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1826 return; 1827 if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) != 0) 1828 instance = find_instance(curthread->td_sleeplocks, lock); 1829 else if ((lock->lo_class->lc_flags & LC_SPINLOCK) != 0) 1830 instance = find_instance(PCPU_GET(spinlocks), lock); 1831 else { 1832 panic("Lock (%s) %s is not sleep or spin!", 1833 lock->lo_class->lc_name, lock->lo_name); 1834 } 1835 file = fixup_filename(file); 1836 switch (flags) { 1837 case LA_UNLOCKED: 1838 if (instance != NULL) 1839 panic("Lock (%s) %s locked @ %s:%d.", 1840 lock->lo_class->lc_name, lock->lo_name, file, line); 1841 break; 1842 case LA_LOCKED: 1843 case LA_LOCKED | LA_RECURSED: 1844 case LA_LOCKED | LA_NOTRECURSED: 1845 case LA_SLOCKED: 1846 case LA_SLOCKED | LA_RECURSED: 1847 case LA_SLOCKED | LA_NOTRECURSED: 1848 case LA_XLOCKED: 1849 case LA_XLOCKED | LA_RECURSED: 1850 case LA_XLOCKED | LA_NOTRECURSED: 1851 if (instance == NULL) { 1852 panic("Lock (%s) %s not locked @ %s:%d.", 1853 lock->lo_class->lc_name, lock->lo_name, file, line); 1854 break; 1855 } 1856 if ((flags & LA_XLOCKED) != 0 && 1857 (instance->li_flags & LI_EXCLUSIVE) == 0) 1858 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1859 lock->lo_class->lc_name, lock->lo_name, file, line); 1860 if ((flags & LA_SLOCKED) != 0 && 1861 (instance->li_flags & LI_EXCLUSIVE) != 0) 1862 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1863 lock->lo_class->lc_name, lock->lo_name, file, line); 1864 if ((flags & LA_RECURSED) != 0 && 1865 (instance->li_flags & LI_RECURSEMASK) == 0) 1866 panic("Lock (%s) %s not recursed @ %s:%d.", 1867 lock->lo_class->lc_name, lock->lo_name, file, line); 1868 if ((flags & LA_NOTRECURSED) != 0 && 1869 (instance->li_flags & LI_RECURSEMASK) != 0) 1870 panic("Lock (%s) %s recursed @ %s:%d.", 1871 lock->lo_class->lc_name, lock->lo_name, file, line); 1872 break; 1873 default: 1874 panic("Invalid lock assertion at %s:%d.", file, line); 1875 1876 } 1877#endif /* INVARIANT_SUPPORT */ 1878} 1879 1880#ifdef DDB 1881static void 1882witness_list(struct thread *td) 1883{ 1884 1885 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1886 KASSERT(kdb_active, ("%s: not in the debugger", __func__)); 1887 1888 if (witness_watch == 0) 1889 return; 1890 1891 witness_list_locks(&td->td_sleeplocks); 1892 1893 /* 1894 * We only handle spinlocks if td == curthread. This is somewhat broken 1895 * if td is currently executing on some other CPU and holds spin locks 1896 * as we won't display those locks. If we had a MI way of getting 1897 * the per-cpu data for a given cpu then we could use 1898 * td->td_oncpu to get the list of spinlocks for this thread 1899 * and "fix" this. 1900 * 1901 * That still wouldn't really fix this unless we locked sched_lock 1902 * or stopped the other CPU to make sure it wasn't changing the list 1903 * out from under us. It is probably best to just not try to handle 1904 * threads on other CPU's for now. 1905 */ 1906 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1907 witness_list_locks(PCPU_PTR(spinlocks)); 1908} 1909 1910DB_SHOW_COMMAND(locks, db_witness_list) 1911{ 1912 struct thread *td; 1913 pid_t pid; 1914 struct proc *p; 1915 1916 if (have_addr) { 1917 pid = (addr % 16) + ((addr >> 4) % 16) * 10 + 1918 ((addr >> 8) % 16) * 100 + ((addr >> 12) % 16) * 1000 + 1919 ((addr >> 16) % 16) * 10000; 1920 /* sx_slock(&allproc_lock); */ 1921 FOREACH_PROC_IN_SYSTEM(p) { 1922 if (p->p_pid == pid) 1923 break; 1924 } 1925 /* sx_sunlock(&allproc_lock); */ 1926 if (p == NULL) { 1927 db_printf("pid %d not found\n", pid); 1928 return; 1929 } 1930 FOREACH_THREAD_IN_PROC(p, td) { 1931 witness_list(td); 1932 } 1933 } else { 1934 td = curthread; 1935 witness_list(td); 1936 } 1937} 1938 1939DB_SHOW_COMMAND(alllocks, db_witness_list_all) 1940{ 1941 struct thread *td; 1942 struct proc *p; 1943 1944 /* 1945 * It would be nice to list only threads and processes that actually 1946 * held sleep locks, but that information is currently not exported 1947 * by WITNESS. 1948 */ 1949 FOREACH_PROC_IN_SYSTEM(p) { 1950 if (!witness_proc_has_locks(p)) 1951 continue; 1952 FOREACH_THREAD_IN_PROC(p, td) { 1953 if (!witness_thread_has_locks(td)) 1954 continue; 1955 printf("Process %d (%s) thread %p (%d)\n", p->p_pid, 1956 p->p_comm, td, td->td_tid); 1957 witness_list(td); 1958 } 1959 } 1960} 1961 1962DB_SHOW_COMMAND(witness, db_witness_display) 1963{ 1964 1965 witness_display(db_printf); 1966} 1967#endif 1968