subr_witness.c revision 177299
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 177299 2008-03-17 11:48:40Z pjd $"); 86 87#include "opt_ddb.h" 88#include "opt_hwpmc_hooks.h" 89#include "opt_witness.h" 90 91#include <sys/param.h> 92#include <sys/bus.h> 93#include <sys/kdb.h> 94#include <sys/kernel.h> 95#include <sys/ktr.h> 96#include <sys/lock.h> 97#include <sys/malloc.h> 98#include <sys/mutex.h> 99#include <sys/priv.h> 100#include <sys/proc.h> 101#include <sys/sysctl.h> 102#include <sys/systm.h> 103 104#include <ddb/ddb.h> 105 106#include <machine/stdarg.h> 107 108/* Note that these traces do not work with KTR_ALQ. */ 109#if 0 110#define KTR_WITNESS KTR_SUBSYS 111#else 112#define KTR_WITNESS 0 113#endif 114 115/* Easier to stay with the old names. */ 116#define lo_list lo_witness_data.lod_list 117#define lo_witness lo_witness_data.lod_witness 118 119/* Define this to check for blessed mutexes */ 120#undef BLESSING 121 122#define WITNESS_COUNT 1024 123#define WITNESS_CHILDCOUNT (WITNESS_COUNT * 4) 124/* 125 * XXX: This is somewhat bogus, as we assume here that at most 1024 threads 126 * will hold LOCK_NCHILDREN * 2 locks. We handle failure ok, and we should 127 * probably be safe for the most part, but it's still a SWAG. 128 */ 129#define LOCK_CHILDCOUNT (MAXCPU + 1024) * 2 130 131#define WITNESS_NCHILDREN 6 132 133struct witness_child_list_entry; 134 135struct witness { 136 const char *w_name; 137 struct lock_class *w_class; 138 STAILQ_ENTRY(witness) w_list; /* List of all witnesses. */ 139 STAILQ_ENTRY(witness) w_typelist; /* Witnesses of a type. */ 140 struct witness_child_list_entry *w_children; /* Great evilness... */ 141 const char *w_file; 142 int w_line; 143 u_int w_level; 144 u_int w_refcount; 145 u_char w_Giant_squawked:1; 146 u_char w_other_squawked:1; 147 u_char w_same_squawked:1; 148 u_char w_displayed:1; 149}; 150 151struct witness_child_list_entry { 152 struct witness_child_list_entry *wcl_next; 153 struct witness *wcl_children[WITNESS_NCHILDREN]; 154 u_int wcl_count; 155}; 156 157STAILQ_HEAD(witness_list, witness); 158 159#ifdef BLESSING 160struct witness_blessed { 161 const char *b_lock1; 162 const char *b_lock2; 163}; 164#endif 165 166struct witness_order_list_entry { 167 const char *w_name; 168 struct lock_class *w_class; 169}; 170 171#ifdef BLESSING 172static int blessed(struct witness *, struct witness *); 173#endif 174static int depart(struct witness *w); 175static struct witness *enroll(const char *description, 176 struct lock_class *lock_class); 177static int insertchild(struct witness *parent, struct witness *child); 178static int isitmychild(struct witness *parent, struct witness *child); 179static int isitmydescendant(struct witness *parent, struct witness *child); 180static int itismychild(struct witness *parent, struct witness *child); 181static void removechild(struct witness *parent, struct witness *child); 182static int sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS); 183static const char *fixup_filename(const char *file); 184static struct witness *witness_get(void); 185static void witness_free(struct witness *m); 186static struct witness_child_list_entry *witness_child_get(void); 187static void witness_child_free(struct witness_child_list_entry *wcl); 188static struct lock_list_entry *witness_lock_list_get(void); 189static void witness_lock_list_free(struct lock_list_entry *lle); 190static struct lock_instance *find_instance(struct lock_list_entry *lock_list, 191 struct lock_object *lock); 192static void witness_list_lock(struct lock_instance *instance); 193#ifdef DDB 194static void witness_leveldescendents(struct witness *parent, int level); 195static void witness_levelall(void); 196static void witness_displaydescendants(void(*)(const char *fmt, ...), 197 struct witness *, int indent); 198static void witness_display_list(void(*prnt)(const char *fmt, ...), 199 struct witness_list *list); 200static void witness_display(void(*)(const char *fmt, ...)); 201static void witness_list(struct thread *td); 202#endif 203 204SYSCTL_NODE(_debug, OID_AUTO, witness, CTLFLAG_RW, 0, "Witness Locking"); 205 206/* 207 * If set to 0, witness is disabled. If set to a non-zero value, witness 208 * performs full lock order checking for all locks. At runtime, this 209 * value may be set to 0 to turn off witness. witness is not allowed be 210 * turned on once it is turned off, however. 211 */ 212static int witness_watch = 1; 213TUNABLE_INT("debug.witness.watch", &witness_watch); 214SYSCTL_PROC(_debug_witness, OID_AUTO, watch, CTLFLAG_RW | CTLTYPE_INT, NULL, 0, 215 sysctl_debug_witness_watch, "I", "witness is watching lock operations"); 216 217#ifdef KDB 218/* 219 * When KDB is enabled and witness_kdb is set to 1, it will cause the system 220 * to drop into kdebug() when: 221 * - a lock hierarchy violation occurs 222 * - locks are held when going to sleep. 223 */ 224#ifdef WITNESS_KDB 225int witness_kdb = 1; 226#else 227int witness_kdb = 0; 228#endif 229TUNABLE_INT("debug.witness.kdb", &witness_kdb); 230SYSCTL_INT(_debug_witness, OID_AUTO, kdb, CTLFLAG_RW, &witness_kdb, 0, ""); 231 232/* 233 * When KDB is enabled and witness_trace is set to 1, it will cause the system 234 * to print a stack trace: 235 * - a lock hierarchy violation occurs 236 * - locks are held when going to sleep. 237 */ 238int witness_trace = 1; 239TUNABLE_INT("debug.witness.trace", &witness_trace); 240SYSCTL_INT(_debug_witness, OID_AUTO, trace, CTLFLAG_RW, &witness_trace, 0, ""); 241#endif /* KDB */ 242 243#ifdef WITNESS_SKIPSPIN 244int witness_skipspin = 1; 245#else 246int witness_skipspin = 0; 247#endif 248TUNABLE_INT("debug.witness.skipspin", &witness_skipspin); 249SYSCTL_INT(_debug_witness, OID_AUTO, skipspin, CTLFLAG_RDTUN, 250 &witness_skipspin, 0, ""); 251 252static struct mtx w_mtx; 253static struct witness_list w_free = STAILQ_HEAD_INITIALIZER(w_free); 254static struct witness_list w_all = STAILQ_HEAD_INITIALIZER(w_all); 255static struct witness_list w_spin = STAILQ_HEAD_INITIALIZER(w_spin); 256static struct witness_list w_sleep = STAILQ_HEAD_INITIALIZER(w_sleep); 257static struct witness_child_list_entry *w_child_free = NULL; 258static struct lock_list_entry *w_lock_list_free = NULL; 259 260static int w_free_cnt, w_spin_cnt, w_sleep_cnt, w_child_free_cnt, w_child_cnt; 261SYSCTL_INT(_debug_witness, OID_AUTO, free_cnt, CTLFLAG_RD, &w_free_cnt, 0, ""); 262SYSCTL_INT(_debug_witness, OID_AUTO, spin_cnt, CTLFLAG_RD, &w_spin_cnt, 0, ""); 263SYSCTL_INT(_debug_witness, OID_AUTO, sleep_cnt, CTLFLAG_RD, &w_sleep_cnt, 0, 264 ""); 265SYSCTL_INT(_debug_witness, OID_AUTO, child_free_cnt, CTLFLAG_RD, 266 &w_child_free_cnt, 0, ""); 267SYSCTL_INT(_debug_witness, OID_AUTO, child_cnt, CTLFLAG_RD, &w_child_cnt, 0, 268 ""); 269 270static struct witness w_data[WITNESS_COUNT]; 271static struct witness_child_list_entry w_childdata[WITNESS_CHILDCOUNT]; 272static struct lock_list_entry w_locklistdata[LOCK_CHILDCOUNT]; 273 274static struct witness_order_list_entry order_lists[] = { 275 /* 276 * sx locks 277 */ 278 { "proctree", &lock_class_sx }, 279 { "allproc", &lock_class_sx }, 280 { "allprison", &lock_class_sx }, 281 { NULL, NULL }, 282 /* 283 * Various mutexes 284 */ 285 { "Giant", &lock_class_mtx_sleep }, 286 { "pipe mutex", &lock_class_mtx_sleep }, 287 { "sigio lock", &lock_class_mtx_sleep }, 288 { "process group", &lock_class_mtx_sleep }, 289 { "process lock", &lock_class_mtx_sleep }, 290 { "session", &lock_class_mtx_sleep }, 291 { "uidinfo hash", &lock_class_rw }, 292#ifdef HWPMC_HOOKS 293 { "pmc-sleep", &lock_class_mtx_sleep }, 294#endif 295 { NULL, NULL }, 296 /* 297 * Sockets 298 */ 299 { "accept", &lock_class_mtx_sleep }, 300 { "so_snd", &lock_class_mtx_sleep }, 301 { "so_rcv", &lock_class_mtx_sleep }, 302 { "sellck", &lock_class_mtx_sleep }, 303 { NULL, NULL }, 304 /* 305 * Routing 306 */ 307 { "so_rcv", &lock_class_mtx_sleep }, 308 { "radix node head", &lock_class_mtx_sleep }, 309 { "rtentry", &lock_class_mtx_sleep }, 310 { "ifaddr", &lock_class_mtx_sleep }, 311 { NULL, NULL }, 312 /* 313 * Multicast - protocol locks before interface locks, after UDP locks. 314 */ 315 { "udpinp", &lock_class_mtx_sleep }, 316 { "in_multi_mtx", &lock_class_mtx_sleep }, 317 { "igmp_mtx", &lock_class_mtx_sleep }, 318 { "if_addr_mtx", &lock_class_mtx_sleep }, 319 { NULL, NULL }, 320 /* 321 * UNIX Domain Sockets 322 */ 323 { "unp", &lock_class_mtx_sleep }, 324 { "so_snd", &lock_class_mtx_sleep }, 325 { NULL, NULL }, 326 /* 327 * UDP/IP 328 */ 329 { "udp", &lock_class_mtx_sleep }, 330 { "udpinp", &lock_class_mtx_sleep }, 331 { "so_snd", &lock_class_mtx_sleep }, 332 { NULL, NULL }, 333 /* 334 * TCP/IP 335 */ 336 { "tcp", &lock_class_mtx_sleep }, 337 { "tcpinp", &lock_class_mtx_sleep }, 338 { "so_snd", &lock_class_mtx_sleep }, 339 { NULL, NULL }, 340 /* 341 * SLIP 342 */ 343 { "slip_mtx", &lock_class_mtx_sleep }, 344 { "slip sc_mtx", &lock_class_mtx_sleep }, 345 { NULL, NULL }, 346 /* 347 * netatalk 348 */ 349 { "ddp_list_mtx", &lock_class_mtx_sleep }, 350 { "ddp_mtx", &lock_class_mtx_sleep }, 351 { NULL, NULL }, 352 /* 353 * BPF 354 */ 355 { "bpf global lock", &lock_class_mtx_sleep }, 356 { "bpf interface lock", &lock_class_mtx_sleep }, 357 { "bpf cdev lock", &lock_class_mtx_sleep }, 358 { NULL, NULL }, 359 /* 360 * NFS server 361 */ 362 { "nfsd_mtx", &lock_class_mtx_sleep }, 363 { "so_snd", &lock_class_mtx_sleep }, 364 { NULL, NULL }, 365 366 /* 367 * IEEE 802.11 368 */ 369 { "802.11 com lock", &lock_class_mtx_sleep}, 370 { NULL, NULL }, 371 /* 372 * Network drivers 373 */ 374 { "network driver", &lock_class_mtx_sleep}, 375 { NULL, NULL }, 376 377 /* 378 * Netgraph 379 */ 380 { "ng_node", &lock_class_mtx_sleep }, 381 { "ng_worklist", &lock_class_mtx_sleep }, 382 { NULL, NULL }, 383 /* 384 * CDEV 385 */ 386 { "system map", &lock_class_mtx_sleep }, 387 { "vm page queue mutex", &lock_class_mtx_sleep }, 388 { "vnode interlock", &lock_class_mtx_sleep }, 389 { "cdev", &lock_class_mtx_sleep }, 390 { NULL, NULL }, 391 /* 392 * kqueue/VFS interaction 393 */ 394 { "kqueue", &lock_class_mtx_sleep }, 395 { "struct mount mtx", &lock_class_mtx_sleep }, 396 { "vnode interlock", &lock_class_mtx_sleep }, 397 { NULL, NULL }, 398 /* 399 * spin locks 400 */ 401#ifdef SMP 402 { "ap boot", &lock_class_mtx_spin }, 403#endif 404 { "rm.mutex_mtx", &lock_class_mtx_spin }, 405 { "sio", &lock_class_mtx_spin }, 406 { "scrlock", &lock_class_mtx_spin }, 407#ifdef __i386__ 408 { "cy", &lock_class_mtx_spin }, 409#endif 410#ifdef __sparc64__ 411 { "pcib_mtx", &lock_class_mtx_spin }, 412 { "rtc_mtx", &lock_class_mtx_spin }, 413#endif 414 { "scc_hwmtx", &lock_class_mtx_spin }, 415 { "uart_hwmtx", &lock_class_mtx_spin }, 416 { "fast_taskqueue", &lock_class_mtx_spin }, 417 { "intr table", &lock_class_mtx_spin }, 418#ifdef HWPMC_HOOKS 419 { "pmc-per-proc", &lock_class_mtx_spin }, 420#endif 421 { "process slock", &lock_class_mtx_spin }, 422 { "sleepq chain", &lock_class_mtx_spin }, 423 { "umtx lock", &lock_class_mtx_spin }, 424 { "rm_spinlock", &lock_class_mtx_spin }, 425 { "turnstile chain", &lock_class_mtx_spin }, 426 { "turnstile lock", &lock_class_mtx_spin }, 427 { "sched lock", &lock_class_mtx_spin }, 428 { "td_contested", &lock_class_mtx_spin }, 429 { "callout", &lock_class_mtx_spin }, 430 { "entropy harvest mutex", &lock_class_mtx_spin }, 431 { "syscons video lock", &lock_class_mtx_spin }, 432 { "time lock", &lock_class_mtx_spin }, 433#ifdef SMP 434 { "smp rendezvous", &lock_class_mtx_spin }, 435#endif 436#ifdef __powerpc__ 437 { "tlb0", &lock_class_mtx_spin }, 438#endif 439 /* 440 * leaf locks 441 */ 442 { "icu", &lock_class_mtx_spin }, 443#if defined(SMP) && defined(__sparc64__) 444 { "ipi", &lock_class_mtx_spin }, 445#endif 446#ifdef __i386__ 447 { "allpmaps", &lock_class_mtx_spin }, 448 { "descriptor tables", &lock_class_mtx_spin }, 449#endif 450 { "clk", &lock_class_mtx_spin }, 451 { "mprof lock", &lock_class_mtx_spin }, 452 { "zombie lock", &lock_class_mtx_spin }, 453 { "ALD Queue", &lock_class_mtx_spin }, 454#ifdef __ia64__ 455 { "MCA spin lock", &lock_class_mtx_spin }, 456#endif 457#if defined(__i386__) || defined(__amd64__) 458 { "pcicfg", &lock_class_mtx_spin }, 459 { "NDIS thread lock", &lock_class_mtx_spin }, 460#endif 461 { "tw_osl_io_lock", &lock_class_mtx_spin }, 462 { "tw_osl_q_lock", &lock_class_mtx_spin }, 463 { "tw_cl_io_lock", &lock_class_mtx_spin }, 464 { "tw_cl_intr_lock", &lock_class_mtx_spin }, 465 { "tw_cl_gen_lock", &lock_class_mtx_spin }, 466#ifdef HWPMC_HOOKS 467 { "pmc-leaf", &lock_class_mtx_spin }, 468#endif 469 { "blocked lock", &lock_class_mtx_spin }, 470 { NULL, NULL }, 471 { NULL, NULL } 472}; 473 474#ifdef BLESSING 475/* 476 * Pairs of locks which have been blessed 477 * Don't complain about order problems with blessed locks 478 */ 479static struct witness_blessed blessed_list[] = { 480}; 481static int blessed_count = 482 sizeof(blessed_list) / sizeof(struct witness_blessed); 483#endif 484 485/* 486 * List of locks initialized prior to witness being initialized whose 487 * enrollment is currently deferred. 488 */ 489STAILQ_HEAD(, lock_object) pending_locks = 490 STAILQ_HEAD_INITIALIZER(pending_locks); 491 492/* 493 * This global is set to 0 once it becomes safe to use the witness code. 494 */ 495static int witness_cold = 1; 496 497/* 498 * This global is set to 1 once the static lock orders have been enrolled 499 * so that a warning can be issued for any spin locks enrolled later. 500 */ 501static int witness_spin_warn = 0; 502 503/* 504 * The WITNESS-enabled diagnostic code. Note that the witness code does 505 * assume that the early boot is single-threaded at least until after this 506 * routine is completed. 507 */ 508static void 509witness_initialize(void *dummy __unused) 510{ 511 struct lock_object *lock; 512 struct witness_order_list_entry *order; 513 struct witness *w, *w1; 514 int i; 515 516 /* 517 * We have to release Giant before initializing its witness 518 * structure so that WITNESS doesn't get confused. 519 */ 520 mtx_unlock(&Giant); 521 mtx_assert(&Giant, MA_NOTOWNED); 522 523 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 524 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 525 MTX_NOWITNESS | MTX_NOPROFILE); 526 for (i = 0; i < WITNESS_COUNT; i++) 527 witness_free(&w_data[i]); 528 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 529 witness_child_free(&w_childdata[i]); 530 for (i = 0; i < LOCK_CHILDCOUNT; i++) 531 witness_lock_list_free(&w_locklistdata[i]); 532 533 /* First add in all the specified order lists. */ 534 for (order = order_lists; order->w_name != NULL; order++) { 535 w = enroll(order->w_name, order->w_class); 536 if (w == NULL) 537 continue; 538 w->w_file = "order list"; 539 for (order++; order->w_name != NULL; order++) { 540 w1 = enroll(order->w_name, order->w_class); 541 if (w1 == NULL) 542 continue; 543 w1->w_file = "order list"; 544 if (!itismychild(w, w1)) 545 panic("Not enough memory for static orders!"); 546 w = w1; 547 } 548 } 549 witness_spin_warn = 1; 550 551 /* Iterate through all locks and add them to witness. */ 552 while (!STAILQ_EMPTY(&pending_locks)) { 553 lock = STAILQ_FIRST(&pending_locks); 554 STAILQ_REMOVE_HEAD(&pending_locks, lo_list); 555 KASSERT(lock->lo_flags & LO_WITNESS, 556 ("%s: lock %s is on pending list but not LO_WITNESS", 557 __func__, lock->lo_name)); 558 lock->lo_witness = enroll(lock->lo_type, LOCK_CLASS(lock)); 559 } 560 561 /* Mark the witness code as being ready for use. */ 562 witness_cold = 0; 563 564 mtx_lock(&Giant); 565} 566SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, 567 NULL); 568 569static int 570sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS) 571{ 572 int error, value; 573 574 value = witness_watch; 575 error = sysctl_handle_int(oidp, &value, 0, req); 576 if (error != 0 || req->newptr == NULL) 577 return (error); 578 if (value == witness_watch) 579 return (0); 580 if (value != 0) 581 return (EINVAL); 582 witness_watch = 0; 583 return (0); 584} 585 586void 587witness_init(struct lock_object *lock) 588{ 589 struct lock_class *class; 590 591 /* Various sanity checks. */ 592 class = LOCK_CLASS(lock); 593 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 594 (class->lc_flags & LC_RECURSABLE) == 0) 595 panic("%s: lock (%s) %s can not be recursable", __func__, 596 class->lc_name, lock->lo_name); 597 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 598 (class->lc_flags & LC_SLEEPABLE) == 0) 599 panic("%s: lock (%s) %s can not be sleepable", __func__, 600 class->lc_name, lock->lo_name); 601 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 602 (class->lc_flags & LC_UPGRADABLE) == 0) 603 panic("%s: lock (%s) %s can not be upgradable", __func__, 604 class->lc_name, lock->lo_name); 605 606 /* 607 * If we shouldn't watch this lock, then just clear lo_witness. 608 * Otherwise, if witness_cold is set, then it is too early to 609 * enroll this lock, so defer it to witness_initialize() by adding 610 * it to the pending_locks list. If it is not too early, then enroll 611 * the lock now. 612 */ 613 if (witness_watch == 0 || panicstr != NULL || 614 (lock->lo_flags & LO_WITNESS) == 0) 615 lock->lo_witness = NULL; 616 else if (witness_cold) { 617 STAILQ_INSERT_TAIL(&pending_locks, lock, lo_list); 618 lock->lo_flags |= LO_ENROLLPEND; 619 } else 620 lock->lo_witness = enroll(lock->lo_type, class); 621} 622 623void 624witness_destroy(struct lock_object *lock) 625{ 626 struct lock_class *class; 627 struct witness *w; 628 629 class = LOCK_CLASS(lock); 630 if (witness_cold) 631 panic("lock (%s) %s destroyed while witness_cold", 632 class->lc_name, lock->lo_name); 633 634 /* XXX: need to verify that no one holds the lock */ 635 if ((lock->lo_flags & (LO_WITNESS | LO_ENROLLPEND)) == LO_WITNESS && 636 lock->lo_witness != NULL) { 637 w = lock->lo_witness; 638 mtx_lock_spin(&w_mtx); 639 MPASS(w->w_refcount > 0); 640 w->w_refcount--; 641 642 /* 643 * Lock is already released if we have an allocation failure 644 * and depart() fails. 645 */ 646 if (w->w_refcount != 0 || depart(w)) 647 mtx_unlock_spin(&w_mtx); 648 } 649 650 /* 651 * If this lock is destroyed before witness is up and running, 652 * remove it from the pending list. 653 */ 654 if (lock->lo_flags & LO_ENROLLPEND) { 655 STAILQ_REMOVE(&pending_locks, lock, lock_object, lo_list); 656 lock->lo_flags &= ~LO_ENROLLPEND; 657 } 658} 659 660#ifdef DDB 661static void 662witness_levelall (void) 663{ 664 struct witness_list *list; 665 struct witness *w, *w1; 666 667 /* 668 * First clear all levels. 669 */ 670 STAILQ_FOREACH(w, &w_all, w_list) { 671 w->w_level = 0; 672 } 673 674 /* 675 * Look for locks with no parent and level all their descendants. 676 */ 677 STAILQ_FOREACH(w, &w_all, w_list) { 678 /* 679 * This is just an optimization, technically we could get 680 * away just walking the all list each time. 681 */ 682 if (w->w_class->lc_flags & LC_SLEEPLOCK) 683 list = &w_sleep; 684 else 685 list = &w_spin; 686 STAILQ_FOREACH(w1, list, w_typelist) { 687 if (isitmychild(w1, w)) 688 goto skip; 689 } 690 witness_leveldescendents(w, 0); 691 skip: 692 ; /* silence GCC 3.x */ 693 } 694} 695 696static void 697witness_leveldescendents(struct witness *parent, int level) 698{ 699 struct witness_child_list_entry *wcl; 700 int i; 701 702 if (parent->w_level < level) 703 parent->w_level = level; 704 level++; 705 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 706 for (i = 0; i < wcl->wcl_count; i++) 707 witness_leveldescendents(wcl->wcl_children[i], level); 708} 709 710static void 711witness_displaydescendants(void(*prnt)(const char *fmt, ...), 712 struct witness *parent, int indent) 713{ 714 struct witness_child_list_entry *wcl; 715 int i, level; 716 717 level = parent->w_level; 718 prnt("%-2d", level); 719 for (i = 0; i < indent; i++) 720 prnt(" "); 721 if (parent->w_refcount > 0) 722 prnt("%s", parent->w_name); 723 else 724 prnt("(dead)"); 725 if (parent->w_displayed) { 726 prnt(" -- (already displayed)\n"); 727 return; 728 } 729 parent->w_displayed = 1; 730 if (parent->w_refcount > 0) { 731 if (parent->w_file != NULL) 732 prnt(" -- last acquired @ %s:%d", parent->w_file, 733 parent->w_line); 734 } 735 prnt("\n"); 736 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 737 for (i = 0; i < wcl->wcl_count; i++) 738 witness_displaydescendants(prnt, 739 wcl->wcl_children[i], indent + 1); 740} 741 742static void 743witness_display_list(void(*prnt)(const char *fmt, ...), 744 struct witness_list *list) 745{ 746 struct witness *w; 747 748 STAILQ_FOREACH(w, list, w_typelist) { 749 if (w->w_file == NULL || w->w_level > 0) 750 continue; 751 /* 752 * This lock has no anscestors, display its descendants. 753 */ 754 witness_displaydescendants(prnt, w, 0); 755 } 756} 757 758static void 759witness_display(void(*prnt)(const char *fmt, ...)) 760{ 761 struct witness *w; 762 763 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 764 witness_levelall(); 765 766 /* Clear all the displayed flags. */ 767 STAILQ_FOREACH(w, &w_all, w_list) { 768 w->w_displayed = 0; 769 } 770 771 /* 772 * First, handle sleep locks which have been acquired at least 773 * once. 774 */ 775 prnt("Sleep locks:\n"); 776 witness_display_list(prnt, &w_sleep); 777 778 /* 779 * Now do spin locks which have been acquired at least once. 780 */ 781 prnt("\nSpin locks:\n"); 782 witness_display_list(prnt, &w_spin); 783 784 /* 785 * Finally, any locks which have not been acquired yet. 786 */ 787 prnt("\nLocks which were never acquired:\n"); 788 STAILQ_FOREACH(w, &w_all, w_list) { 789 if (w->w_file != NULL || w->w_refcount == 0) 790 continue; 791 prnt("%s\n", w->w_name); 792 } 793} 794#endif /* DDB */ 795 796/* Trim useless garbage from filenames. */ 797static const char * 798fixup_filename(const char *file) 799{ 800 801 if (file == NULL) 802 return (NULL); 803 while (strncmp(file, "../", 3) == 0) 804 file += 3; 805 return (file); 806} 807 808int 809witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) 810{ 811 812 if (witness_watch == 0 || panicstr != NULL) 813 return (0); 814 815 /* Require locks that witness knows about. */ 816 if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || 817 lock2->lo_witness == NULL) 818 return (EINVAL); 819 820 MPASS(!mtx_owned(&w_mtx)); 821 mtx_lock_spin(&w_mtx); 822 823 /* 824 * If we already have either an explicit or implied lock order that 825 * is the other way around, then return an error. 826 */ 827 if (isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { 828 mtx_unlock_spin(&w_mtx); 829 return (EDOOFUS); 830 } 831 832 /* Try to add the new order. */ 833 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 834 lock2->lo_type, lock1->lo_type); 835 if (!itismychild(lock1->lo_witness, lock2->lo_witness)) 836 return (ENOMEM); 837 mtx_unlock_spin(&w_mtx); 838 return (0); 839} 840 841void 842witness_checkorder(struct lock_object *lock, int flags, const char *file, 843 int line) 844{ 845 struct lock_list_entry **lock_list, *lle; 846 struct lock_instance *lock1, *lock2; 847 struct lock_class *class; 848 struct witness *w, *w1; 849 struct thread *td; 850 int i, j; 851 852 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 853 panicstr != NULL) 854 return; 855 856 /* 857 * Try locks do not block if they fail to acquire the lock, thus 858 * there is no danger of deadlocks or of switching while holding a 859 * spin lock if we acquire a lock via a try operation. This 860 * function shouldn't even be called for try locks, so panic if 861 * that happens. 862 */ 863 if (flags & LOP_TRYLOCK) 864 panic("%s should not be called for try lock operations", 865 __func__); 866 867 w = lock->lo_witness; 868 class = LOCK_CLASS(lock); 869 td = curthread; 870 file = fixup_filename(file); 871 872 if (class->lc_flags & LC_SLEEPLOCK) { 873 /* 874 * Since spin locks include a critical section, this check 875 * implicitly enforces a lock order of all sleep locks before 876 * all spin locks. 877 */ 878 if (td->td_critnest != 0 && !kdb_active) 879 panic("blockable sleep lock (%s) %s @ %s:%d", 880 class->lc_name, lock->lo_name, file, line); 881 882 /* 883 * If this is the first lock acquired then just return as 884 * no order checking is needed. 885 */ 886 if (td->td_sleeplocks == NULL) 887 return; 888 lock_list = &td->td_sleeplocks; 889 } else { 890 /* 891 * If this is the first lock, just return as no order 892 * checking is needed. We check this in both if clauses 893 * here as unifying the check would require us to use a 894 * critical section to ensure we don't migrate while doing 895 * the check. Note that if this is not the first lock, we 896 * are already in a critical section and are safe for the 897 * rest of the check. 898 */ 899 if (PCPU_GET(spinlocks) == NULL) 900 return; 901 lock_list = PCPU_PTR(spinlocks); 902 } 903 904 /* 905 * Check to see if we are recursing on a lock we already own. If 906 * so, make sure that we don't mismatch exclusive and shared lock 907 * acquires. 908 */ 909 lock1 = find_instance(*lock_list, lock); 910 if (lock1 != NULL) { 911 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 912 (flags & LOP_EXCLUSIVE) == 0) { 913 printf("shared lock of (%s) %s @ %s:%d\n", 914 class->lc_name, lock->lo_name, file, line); 915 printf("while exclusively locked from %s:%d\n", 916 lock1->li_file, lock1->li_line); 917 panic("share->excl"); 918 } 919 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 920 (flags & LOP_EXCLUSIVE) != 0) { 921 printf("exclusive lock of (%s) %s @ %s:%d\n", 922 class->lc_name, lock->lo_name, file, line); 923 printf("while share locked from %s:%d\n", 924 lock1->li_file, lock1->li_line); 925 panic("excl->share"); 926 } 927 return; 928 } 929 930 /* 931 * Try locks do not block if they fail to acquire the lock, thus 932 * there is no danger of deadlocks or of switching while holding a 933 * spin lock if we acquire a lock via a try operation. 934 */ 935 if (flags & LOP_TRYLOCK) 936 return; 937 938 /* 939 * Check for duplicate locks of the same type. Note that we only 940 * have to check for this on the last lock we just acquired. Any 941 * other cases will be caught as lock order violations. 942 */ 943 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 944 w1 = lock1->li_lock->lo_witness; 945 if (w1 == w) { 946 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK) || 947 (flags & LOP_DUPOK)) 948 return; 949 w->w_same_squawked = 1; 950 printf("acquiring duplicate lock of same type: \"%s\"\n", 951 lock->lo_type); 952 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 953 lock1->li_file, lock1->li_line); 954 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 955#ifdef KDB 956 goto debugger; 957#else 958 return; 959#endif 960 } 961 MPASS(!mtx_owned(&w_mtx)); 962 mtx_lock_spin(&w_mtx); 963 /* 964 * If we know that the the lock we are acquiring comes after 965 * the lock we most recently acquired in the lock order tree, 966 * then there is no need for any further checks. 967 */ 968 if (isitmychild(w1, w)) { 969 mtx_unlock_spin(&w_mtx); 970 return; 971 } 972 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 973 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 974 975 MPASS(j < WITNESS_COUNT); 976 lock1 = &lle->ll_children[i]; 977 w1 = lock1->li_lock->lo_witness; 978 979 /* 980 * If this lock doesn't undergo witness checking, 981 * then skip it. 982 */ 983 if (w1 == NULL) { 984 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 985 ("lock missing witness structure")); 986 continue; 987 } 988 /* 989 * If we are locking Giant and this is a sleepable 990 * lock, then skip it. 991 */ 992 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && 993 lock == &Giant.lock_object) 994 continue; 995 /* 996 * If we are locking a sleepable lock and this lock 997 * is Giant, then skip it. 998 */ 999 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 1000 lock1->li_lock == &Giant.lock_object) 1001 continue; 1002 /* 1003 * If we are locking a sleepable lock and this lock 1004 * isn't sleepable, we want to treat it as a lock 1005 * order violation to enfore a general lock order of 1006 * sleepable locks before non-sleepable locks. 1007 */ 1008 if (((lock->lo_flags & LO_SLEEPABLE) != 0 && 1009 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 1010 goto reversal; 1011 /* 1012 * If we are locking Giant and this is a non-sleepable 1013 * lock, then treat it as a reversal. 1014 */ 1015 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && 1016 lock == &Giant.lock_object) 1017 goto reversal; 1018 /* 1019 * Check the lock order hierarchy for a reveresal. 1020 */ 1021 if (!isitmydescendant(w, w1)) 1022 continue; 1023 reversal: 1024 /* 1025 * We have a lock order violation, check to see if it 1026 * is allowed or has already been yelled about. 1027 */ 1028 mtx_unlock_spin(&w_mtx); 1029#ifdef BLESSING 1030 /* 1031 * If the lock order is blessed, just bail. We don't 1032 * look for other lock order violations though, which 1033 * may be a bug. 1034 */ 1035 if (blessed(w, w1)) 1036 return; 1037#endif 1038 if (lock1->li_lock == &Giant.lock_object) { 1039 if (w1->w_Giant_squawked) 1040 return; 1041 else 1042 w1->w_Giant_squawked = 1; 1043 } else { 1044 if (w1->w_other_squawked) 1045 return; 1046 else 1047 w1->w_other_squawked = 1; 1048 } 1049 /* 1050 * Ok, yell about it. 1051 */ 1052 if (((lock->lo_flags & LO_SLEEPABLE) != 0 && 1053 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 1054 printf( 1055 "lock order reversal: (sleepable after non-sleepable)\n"); 1056 else if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 1057 && lock == &Giant.lock_object) 1058 printf( 1059 "lock order reversal: (Giant after non-sleepable)\n"); 1060 else 1061 printf("lock order reversal:\n"); 1062 /* 1063 * Try to locate an earlier lock with 1064 * witness w in our list. 1065 */ 1066 do { 1067 lock2 = &lle->ll_children[i]; 1068 MPASS(lock2->li_lock != NULL); 1069 if (lock2->li_lock->lo_witness == w) 1070 break; 1071 if (i == 0 && lle->ll_next != NULL) { 1072 lle = lle->ll_next; 1073 i = lle->ll_count - 1; 1074 MPASS(i >= 0 && i < LOCK_NCHILDREN); 1075 } else 1076 i--; 1077 } while (i >= 0); 1078 if (i < 0) { 1079 printf(" 1st %p %s (%s) @ %s:%d\n", 1080 lock1->li_lock, lock1->li_lock->lo_name, 1081 lock1->li_lock->lo_type, lock1->li_file, 1082 lock1->li_line); 1083 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 1084 lock->lo_name, lock->lo_type, file, line); 1085 } else { 1086 printf(" 1st %p %s (%s) @ %s:%d\n", 1087 lock2->li_lock, lock2->li_lock->lo_name, 1088 lock2->li_lock->lo_type, lock2->li_file, 1089 lock2->li_line); 1090 printf(" 2nd %p %s (%s) @ %s:%d\n", 1091 lock1->li_lock, lock1->li_lock->lo_name, 1092 lock1->li_lock->lo_type, lock1->li_file, 1093 lock1->li_line); 1094 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 1095 lock->lo_name, lock->lo_type, file, line); 1096 } 1097#ifdef KDB 1098 goto debugger; 1099#else 1100 return; 1101#endif 1102 } 1103 } 1104 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 1105 /* 1106 * If requested, build a new lock order. However, don't build a new 1107 * relationship between a sleepable lock and Giant if it is in the 1108 * wrong direction. The correct lock order is that sleepable locks 1109 * always come before Giant. 1110 */ 1111 if (flags & LOP_NEWORDER && 1112 !(lock1->li_lock == &Giant.lock_object && 1113 (lock->lo_flags & LO_SLEEPABLE) != 0)) { 1114 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 1115 lock->lo_type, lock1->li_lock->lo_type); 1116 if (!itismychild(lock1->li_lock->lo_witness, w)) 1117 /* Witness is dead. */ 1118 return; 1119 } 1120 mtx_unlock_spin(&w_mtx); 1121 return; 1122 1123#ifdef KDB 1124debugger: 1125 if (witness_trace) 1126 kdb_backtrace(); 1127 if (witness_kdb) 1128 kdb_enter(KDB_WHY_WITNESS, __func__); 1129#endif 1130} 1131 1132void 1133witness_lock(struct lock_object *lock, int flags, const char *file, int line) 1134{ 1135 struct lock_list_entry **lock_list, *lle; 1136 struct lock_instance *instance; 1137 struct witness *w; 1138 struct thread *td; 1139 1140 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1141 panicstr != NULL) 1142 return; 1143 w = lock->lo_witness; 1144 td = curthread; 1145 file = fixup_filename(file); 1146 1147 /* Determine lock list for this lock. */ 1148 if (LOCK_CLASS(lock)->lc_flags & LC_SLEEPLOCK) 1149 lock_list = &td->td_sleeplocks; 1150 else 1151 lock_list = PCPU_PTR(spinlocks); 1152 1153 /* Check to see if we are recursing on a lock we already own. */ 1154 instance = find_instance(*lock_list, lock); 1155 if (instance != NULL) { 1156 instance->li_flags++; 1157 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 1158 td->td_proc->p_pid, lock->lo_name, 1159 instance->li_flags & LI_RECURSEMASK); 1160 instance->li_file = file; 1161 instance->li_line = line; 1162 return; 1163 } 1164 1165 /* Update per-witness last file and line acquire. */ 1166 w->w_file = file; 1167 w->w_line = line; 1168 1169 /* Find the next open lock instance in the list and fill it. */ 1170 lle = *lock_list; 1171 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 1172 lle = witness_lock_list_get(); 1173 if (lle == NULL) 1174 return; 1175 lle->ll_next = *lock_list; 1176 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 1177 td->td_proc->p_pid, lle); 1178 *lock_list = lle; 1179 } 1180 instance = &lle->ll_children[lle->ll_count++]; 1181 instance->li_lock = lock; 1182 instance->li_line = line; 1183 instance->li_file = file; 1184 if ((flags & LOP_EXCLUSIVE) != 0) 1185 instance->li_flags = LI_EXCLUSIVE; 1186 else 1187 instance->li_flags = 0; 1188 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 1189 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 1190} 1191 1192void 1193witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 1194{ 1195 struct lock_instance *instance; 1196 struct lock_class *class; 1197 1198 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1199 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1200 return; 1201 class = LOCK_CLASS(lock); 1202 file = fixup_filename(file); 1203 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1204 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 1205 class->lc_name, lock->lo_name, file, line); 1206 if ((flags & LOP_TRYLOCK) == 0) 1207 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 1208 lock->lo_name, file, line); 1209 if ((class->lc_flags & LC_SLEEPLOCK) == 0) 1210 panic("upgrade of non-sleep lock (%s) %s @ %s:%d", 1211 class->lc_name, lock->lo_name, file, line); 1212 instance = find_instance(curthread->td_sleeplocks, lock); 1213 if (instance == NULL) 1214 panic("upgrade of unlocked lock (%s) %s @ %s:%d", 1215 class->lc_name, lock->lo_name, file, line); 1216 if ((instance->li_flags & LI_EXCLUSIVE) != 0) 1217 panic("upgrade of exclusive lock (%s) %s @ %s:%d", 1218 class->lc_name, lock->lo_name, file, line); 1219 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1220 panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d", 1221 class->lc_name, lock->lo_name, 1222 instance->li_flags & LI_RECURSEMASK, file, line); 1223 instance->li_flags |= LI_EXCLUSIVE; 1224} 1225 1226void 1227witness_downgrade(struct lock_object *lock, int flags, const char *file, 1228 int line) 1229{ 1230 struct lock_instance *instance; 1231 struct lock_class *class; 1232 1233 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1234 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1235 return; 1236 class = LOCK_CLASS(lock); 1237 file = fixup_filename(file); 1238 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1239 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 1240 class->lc_name, lock->lo_name, file, line); 1241 if ((class->lc_flags & LC_SLEEPLOCK) == 0) 1242 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 1243 class->lc_name, lock->lo_name, file, line); 1244 instance = find_instance(curthread->td_sleeplocks, lock); 1245 if (instance == NULL) 1246 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 1247 class->lc_name, lock->lo_name, file, line); 1248 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 1249 panic("downgrade of shared lock (%s) %s @ %s:%d", 1250 class->lc_name, lock->lo_name, file, line); 1251 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1252 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 1253 class->lc_name, lock->lo_name, 1254 instance->li_flags & LI_RECURSEMASK, file, line); 1255 instance->li_flags &= ~LI_EXCLUSIVE; 1256} 1257 1258void 1259witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 1260{ 1261 struct lock_list_entry **lock_list, *lle; 1262 struct lock_instance *instance; 1263 struct lock_class *class; 1264 struct thread *td; 1265 register_t s; 1266 int i, j; 1267 1268 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1269 panicstr != NULL) 1270 return; 1271 td = curthread; 1272 class = LOCK_CLASS(lock); 1273 file = fixup_filename(file); 1274 1275 /* Find lock instance associated with this lock. */ 1276 if (class->lc_flags & LC_SLEEPLOCK) 1277 lock_list = &td->td_sleeplocks; 1278 else 1279 lock_list = PCPU_PTR(spinlocks); 1280 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 1281 for (i = 0; i < (*lock_list)->ll_count; i++) { 1282 instance = &(*lock_list)->ll_children[i]; 1283 if (instance->li_lock == lock) 1284 goto found; 1285 } 1286 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 1287 file, line); 1288found: 1289 1290 /* First, check for shared/exclusive mismatches. */ 1291 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 1292 (flags & LOP_EXCLUSIVE) == 0) { 1293 printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name, 1294 lock->lo_name, file, line); 1295 printf("while exclusively locked from %s:%d\n", 1296 instance->li_file, instance->li_line); 1297 panic("excl->ushare"); 1298 } 1299 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 1300 (flags & LOP_EXCLUSIVE) != 0) { 1301 printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name, 1302 lock->lo_name, file, line); 1303 printf("while share locked from %s:%d\n", instance->li_file, 1304 instance->li_line); 1305 panic("share->uexcl"); 1306 } 1307 1308 /* If we are recursed, unrecurse. */ 1309 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 1310 CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, 1311 td->td_proc->p_pid, instance->li_lock->lo_name, 1312 instance->li_flags); 1313 instance->li_flags--; 1314 return; 1315 } 1316 1317 /* Otherwise, remove this item from the list. */ 1318 s = intr_disable(); 1319 CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, 1320 td->td_proc->p_pid, instance->li_lock->lo_name, 1321 (*lock_list)->ll_count - 1); 1322 for (j = i; j < (*lock_list)->ll_count - 1; j++) 1323 (*lock_list)->ll_children[j] = 1324 (*lock_list)->ll_children[j + 1]; 1325 (*lock_list)->ll_count--; 1326 intr_restore(s); 1327 1328 /* If this lock list entry is now empty, free it. */ 1329 if ((*lock_list)->ll_count == 0) { 1330 lle = *lock_list; 1331 *lock_list = lle->ll_next; 1332 CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, 1333 td->td_proc->p_pid, lle); 1334 witness_lock_list_free(lle); 1335 } 1336} 1337 1338/* 1339 * Warn if any locks other than 'lock' are held. Flags can be passed in to 1340 * exempt Giant and sleepable locks from the checks as well. If any 1341 * non-exempt locks are held, then a supplied message is printed to the 1342 * console along with a list of the offending locks. If indicated in the 1343 * flags then a failure results in a panic as well. 1344 */ 1345int 1346witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) 1347{ 1348 struct lock_list_entry *lle; 1349 struct lock_instance *lock1; 1350 struct thread *td; 1351 va_list ap; 1352 int i, n; 1353 1354 if (witness_cold || witness_watch == 0 || panicstr != NULL) 1355 return (0); 1356 n = 0; 1357 td = curthread; 1358 for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next) 1359 for (i = lle->ll_count - 1; i >= 0; i--) { 1360 lock1 = &lle->ll_children[i]; 1361 if (lock1->li_lock == lock) 1362 continue; 1363 if (flags & WARN_GIANTOK && 1364 lock1->li_lock == &Giant.lock_object) 1365 continue; 1366 if (flags & WARN_SLEEPOK && 1367 (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) 1368 continue; 1369 if (n == 0) { 1370 va_start(ap, fmt); 1371 vprintf(fmt, ap); 1372 va_end(ap); 1373 printf(" with the following"); 1374 if (flags & WARN_SLEEPOK) 1375 printf(" non-sleepable"); 1376 printf(" locks held:\n"); 1377 } 1378 n++; 1379 witness_list_lock(lock1); 1380 } 1381 if (PCPU_GET(spinlocks) != NULL) { 1382 /* 1383 * Since we already hold a spinlock preemption is 1384 * already blocked. 1385 */ 1386 if (n == 0) { 1387 va_start(ap, fmt); 1388 vprintf(fmt, ap); 1389 va_end(ap); 1390 printf(" with the following"); 1391 if (flags & WARN_SLEEPOK) 1392 printf(" non-sleepable"); 1393 printf(" locks held:\n"); 1394 } 1395 n += witness_list_locks(PCPU_PTR(spinlocks)); 1396 } 1397 if (flags & WARN_PANIC && n) 1398 panic("witness_warn"); 1399#ifdef KDB 1400 else if (witness_kdb && n) 1401 kdb_enter(KDB_WHY_WITNESS, __func__); 1402 else if (witness_trace && n) 1403 kdb_backtrace(); 1404#endif 1405 return (n); 1406} 1407 1408const char * 1409witness_file(struct lock_object *lock) 1410{ 1411 struct witness *w; 1412 1413 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1414 return ("?"); 1415 w = lock->lo_witness; 1416 return (w->w_file); 1417} 1418 1419int 1420witness_line(struct lock_object *lock) 1421{ 1422 struct witness *w; 1423 1424 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1425 return (0); 1426 w = lock->lo_witness; 1427 return (w->w_line); 1428} 1429 1430static struct witness * 1431enroll(const char *description, struct lock_class *lock_class) 1432{ 1433 struct witness *w; 1434 1435 if (witness_watch == 0 || panicstr != NULL) 1436 return (NULL); 1437 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 1438 return (NULL); 1439 mtx_lock_spin(&w_mtx); 1440 STAILQ_FOREACH(w, &w_all, w_list) { 1441 if (w->w_name == description || (w->w_refcount > 0 && 1442 strcmp(description, w->w_name) == 0)) { 1443 w->w_refcount++; 1444 mtx_unlock_spin(&w_mtx); 1445 if (lock_class != w->w_class) 1446 panic( 1447 "lock (%s) %s does not match earlier (%s) lock", 1448 description, lock_class->lc_name, 1449 w->w_class->lc_name); 1450 return (w); 1451 } 1452 } 1453 if ((w = witness_get()) == NULL) 1454 goto out; 1455 w->w_name = description; 1456 w->w_class = lock_class; 1457 w->w_refcount = 1; 1458 STAILQ_INSERT_HEAD(&w_all, w, w_list); 1459 if (lock_class->lc_flags & LC_SPINLOCK) { 1460 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 1461 w_spin_cnt++; 1462 } else if (lock_class->lc_flags & LC_SLEEPLOCK) { 1463 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 1464 w_sleep_cnt++; 1465 } else { 1466 mtx_unlock_spin(&w_mtx); 1467 panic("lock class %s is not sleep or spin", 1468 lock_class->lc_name); 1469 } 1470 mtx_unlock_spin(&w_mtx); 1471out: 1472 /* 1473 * We issue a warning for any spin locks not defined in the static 1474 * order list as a way to discourage their use (folks should really 1475 * be using non-spin mutexes most of the time). However, several 1476 * 3rd part device drivers use spin locks because that is all they 1477 * have available on Windows and Linux and they think that normal 1478 * mutexes are insufficient. 1479 */ 1480 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_spin_warn) 1481 printf("WITNESS: spin lock %s not in order list\n", 1482 description); 1483 return (w); 1484} 1485 1486/* Don't let the door bang you on the way out... */ 1487static int 1488depart(struct witness *w) 1489{ 1490 struct witness_child_list_entry *wcl, *nwcl; 1491 struct witness_list *list; 1492 struct witness *parent; 1493 1494 MPASS(w->w_refcount == 0); 1495 if (w->w_class->lc_flags & LC_SLEEPLOCK) { 1496 list = &w_sleep; 1497 w_sleep_cnt--; 1498 } else { 1499 list = &w_spin; 1500 w_spin_cnt--; 1501 } 1502 /* 1503 * First, we run through the entire tree looking for any 1504 * witnesses that the outgoing witness is a child of. For 1505 * each parent that we find, we reparent all the direct 1506 * children of the outgoing witness to its parent. 1507 */ 1508 STAILQ_FOREACH(parent, list, w_typelist) { 1509 if (!isitmychild(parent, w)) 1510 continue; 1511 removechild(parent, w); 1512 } 1513 1514 /* 1515 * Now we go through and free up the child list of the 1516 * outgoing witness. 1517 */ 1518 for (wcl = w->w_children; wcl != NULL; wcl = nwcl) { 1519 nwcl = wcl->wcl_next; 1520 w_child_cnt--; 1521 witness_child_free(wcl); 1522 } 1523 1524 /* 1525 * Detach from various lists and free. 1526 */ 1527 STAILQ_REMOVE(list, w, witness, w_typelist); 1528 STAILQ_REMOVE(&w_all, w, witness, w_list); 1529 witness_free(w); 1530 1531 return (1); 1532} 1533 1534/* 1535 * Add "child" as a direct child of "parent". Returns false if 1536 * we fail due to out of memory. 1537 */ 1538static int 1539insertchild(struct witness *parent, struct witness *child) 1540{ 1541 struct witness_child_list_entry **wcl; 1542 1543 MPASS(child != NULL && parent != NULL); 1544 1545 /* 1546 * Insert "child" after "parent" 1547 */ 1548 wcl = &parent->w_children; 1549 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1550 wcl = &(*wcl)->wcl_next; 1551 if (*wcl == NULL) { 1552 *wcl = witness_child_get(); 1553 if (*wcl == NULL) 1554 return (0); 1555 w_child_cnt++; 1556 } 1557 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1558 1559 return (1); 1560} 1561 1562 1563static int 1564itismychild(struct witness *parent, struct witness *child) 1565{ 1566 struct witness_list *list; 1567 1568 MPASS(child != NULL && parent != NULL); 1569 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 1570 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 1571 panic( 1572 "%s: parent (%s) and child (%s) are not the same lock type", 1573 __func__, parent->w_class->lc_name, 1574 child->w_class->lc_name); 1575 1576 if (!insertchild(parent, child)) 1577 return (0); 1578 1579 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1580 list = &w_sleep; 1581 else 1582 list = &w_spin; 1583 return (1); 1584} 1585 1586static void 1587removechild(struct witness *parent, struct witness *child) 1588{ 1589 struct witness_child_list_entry **wcl, *wcl1; 1590 int i; 1591 1592 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1593 for (i = 0; i < (*wcl)->wcl_count; i++) 1594 if ((*wcl)->wcl_children[i] == child) 1595 goto found; 1596 return; 1597found: 1598 (*wcl)->wcl_count--; 1599 if ((*wcl)->wcl_count > i) 1600 (*wcl)->wcl_children[i] = 1601 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1602 MPASS((*wcl)->wcl_children[i] != NULL); 1603 if ((*wcl)->wcl_count != 0) 1604 return; 1605 wcl1 = *wcl; 1606 *wcl = wcl1->wcl_next; 1607 w_child_cnt--; 1608 witness_child_free(wcl1); 1609} 1610 1611static int 1612isitmychild(struct witness *parent, struct witness *child) 1613{ 1614 struct witness_child_list_entry *wcl; 1615 int i; 1616 1617 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1618 for (i = 0; i < wcl->wcl_count; i++) { 1619 if (wcl->wcl_children[i] == child) 1620 return (1); 1621 } 1622 } 1623 return (0); 1624} 1625 1626static int 1627isitmydescendant(struct witness *parent, struct witness *child) 1628{ 1629 struct witness_child_list_entry *wcl; 1630 int i, j; 1631 1632 if (isitmychild(parent, child)) 1633 return (1); 1634 j = 0; 1635 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1636 MPASS(j < 1000); 1637 for (i = 0; i < wcl->wcl_count; i++) { 1638 if (isitmydescendant(wcl->wcl_children[i], child)) 1639 return (1); 1640 } 1641 j++; 1642 } 1643 return (0); 1644} 1645 1646#ifdef BLESSING 1647static int 1648blessed(struct witness *w1, struct witness *w2) 1649{ 1650 int i; 1651 struct witness_blessed *b; 1652 1653 for (i = 0; i < blessed_count; i++) { 1654 b = &blessed_list[i]; 1655 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1656 if (strcmp(w2->w_name, b->b_lock2) == 0) 1657 return (1); 1658 continue; 1659 } 1660 if (strcmp(w1->w_name, b->b_lock2) == 0) 1661 if (strcmp(w2->w_name, b->b_lock1) == 0) 1662 return (1); 1663 } 1664 return (0); 1665} 1666#endif 1667 1668static struct witness * 1669witness_get(void) 1670{ 1671 struct witness *w; 1672 1673 if (witness_watch == 0) { 1674 mtx_unlock_spin(&w_mtx); 1675 return (NULL); 1676 } 1677 if (STAILQ_EMPTY(&w_free)) { 1678 witness_watch = 0; 1679 mtx_unlock_spin(&w_mtx); 1680 printf("%s: witness exhausted\n", __func__); 1681 return (NULL); 1682 } 1683 w = STAILQ_FIRST(&w_free); 1684 STAILQ_REMOVE_HEAD(&w_free, w_list); 1685 w_free_cnt--; 1686 bzero(w, sizeof(*w)); 1687 return (w); 1688} 1689 1690static void 1691witness_free(struct witness *w) 1692{ 1693 1694 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1695 w_free_cnt++; 1696} 1697 1698static struct witness_child_list_entry * 1699witness_child_get(void) 1700{ 1701 struct witness_child_list_entry *wcl; 1702 1703 if (witness_watch == 0) { 1704 mtx_unlock_spin(&w_mtx); 1705 return (NULL); 1706 } 1707 wcl = w_child_free; 1708 if (wcl == NULL) { 1709 witness_watch = 0; 1710 mtx_unlock_spin(&w_mtx); 1711 printf("%s: witness exhausted\n", __func__); 1712 return (NULL); 1713 } 1714 w_child_free = wcl->wcl_next; 1715 w_child_free_cnt--; 1716 bzero(wcl, sizeof(*wcl)); 1717 return (wcl); 1718} 1719 1720static void 1721witness_child_free(struct witness_child_list_entry *wcl) 1722{ 1723 1724 wcl->wcl_next = w_child_free; 1725 w_child_free = wcl; 1726 w_child_free_cnt++; 1727} 1728 1729static struct lock_list_entry * 1730witness_lock_list_get(void) 1731{ 1732 struct lock_list_entry *lle; 1733 1734 if (witness_watch == 0) 1735 return (NULL); 1736 mtx_lock_spin(&w_mtx); 1737 lle = w_lock_list_free; 1738 if (lle == NULL) { 1739 witness_watch = 0; 1740 mtx_unlock_spin(&w_mtx); 1741 printf("%s: witness exhausted\n", __func__); 1742 return (NULL); 1743 } 1744 w_lock_list_free = lle->ll_next; 1745 mtx_unlock_spin(&w_mtx); 1746 bzero(lle, sizeof(*lle)); 1747 return (lle); 1748} 1749 1750static void 1751witness_lock_list_free(struct lock_list_entry *lle) 1752{ 1753 1754 mtx_lock_spin(&w_mtx); 1755 lle->ll_next = w_lock_list_free; 1756 w_lock_list_free = lle; 1757 mtx_unlock_spin(&w_mtx); 1758} 1759 1760static struct lock_instance * 1761find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1762{ 1763 struct lock_list_entry *lle; 1764 struct lock_instance *instance; 1765 int i; 1766 1767 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1768 for (i = lle->ll_count - 1; i >= 0; i--) { 1769 instance = &lle->ll_children[i]; 1770 if (instance->li_lock == lock) 1771 return (instance); 1772 } 1773 return (NULL); 1774} 1775 1776static void 1777witness_list_lock(struct lock_instance *instance) 1778{ 1779 struct lock_object *lock; 1780 1781 lock = instance->li_lock; 1782 printf("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1783 "exclusive" : "shared", LOCK_CLASS(lock)->lc_name, lock->lo_name); 1784 if (lock->lo_type != lock->lo_name) 1785 printf(" (%s)", lock->lo_type); 1786 printf(" r = %d (%p) locked @ %s:%d\n", 1787 instance->li_flags & LI_RECURSEMASK, lock, instance->li_file, 1788 instance->li_line); 1789} 1790 1791#ifdef DDB 1792static int 1793witness_thread_has_locks(struct thread *td) 1794{ 1795 1796 return (td->td_sleeplocks != NULL); 1797} 1798 1799static int 1800witness_proc_has_locks(struct proc *p) 1801{ 1802 struct thread *td; 1803 1804 FOREACH_THREAD_IN_PROC(p, td) { 1805 if (witness_thread_has_locks(td)) 1806 return (1); 1807 } 1808 return (0); 1809} 1810#endif 1811 1812int 1813witness_list_locks(struct lock_list_entry **lock_list) 1814{ 1815 struct lock_list_entry *lle; 1816 int i, nheld; 1817 1818 nheld = 0; 1819 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1820 for (i = lle->ll_count - 1; i >= 0; i--) { 1821 witness_list_lock(&lle->ll_children[i]); 1822 nheld++; 1823 } 1824 return (nheld); 1825} 1826 1827/* 1828 * This is a bit risky at best. We call this function when we have timed 1829 * out acquiring a spin lock, and we assume that the other CPU is stuck 1830 * with this lock held. So, we go groveling around in the other CPU's 1831 * per-cpu data to try to find the lock instance for this spin lock to 1832 * see when it was last acquired. 1833 */ 1834void 1835witness_display_spinlock(struct lock_object *lock, struct thread *owner) 1836{ 1837 struct lock_instance *instance; 1838 struct pcpu *pc; 1839 1840 if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU) 1841 return; 1842 pc = pcpu_find(owner->td_oncpu); 1843 instance = find_instance(pc->pc_spinlocks, lock); 1844 if (instance != NULL) 1845 witness_list_lock(instance); 1846} 1847 1848void 1849witness_save(struct lock_object *lock, const char **filep, int *linep) 1850{ 1851 struct lock_list_entry *lock_list; 1852 struct lock_instance *instance; 1853 struct lock_class *class; 1854 1855 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1856 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1857 return; 1858 class = LOCK_CLASS(lock); 1859 if (class->lc_flags & LC_SLEEPLOCK) 1860 lock_list = curthread->td_sleeplocks; 1861 else { 1862 if (witness_skipspin) 1863 return; 1864 lock_list = PCPU_GET(spinlocks); 1865 } 1866 instance = find_instance(lock_list, lock); 1867 if (instance == NULL) 1868 panic("%s: lock (%s) %s not locked", __func__, 1869 class->lc_name, lock->lo_name); 1870 *filep = instance->li_file; 1871 *linep = instance->li_line; 1872} 1873 1874void 1875witness_restore(struct lock_object *lock, const char *file, int line) 1876{ 1877 struct lock_list_entry *lock_list; 1878 struct lock_instance *instance; 1879 struct lock_class *class; 1880 1881 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1882 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1883 return; 1884 class = LOCK_CLASS(lock); 1885 if (class->lc_flags & LC_SLEEPLOCK) 1886 lock_list = curthread->td_sleeplocks; 1887 else { 1888 if (witness_skipspin) 1889 return; 1890 lock_list = PCPU_GET(spinlocks); 1891 } 1892 instance = find_instance(lock_list, lock); 1893 if (instance == NULL) 1894 panic("%s: lock (%s) %s not locked", __func__, 1895 class->lc_name, lock->lo_name); 1896 lock->lo_witness->w_file = file; 1897 lock->lo_witness->w_line = line; 1898 instance->li_file = file; 1899 instance->li_line = line; 1900} 1901 1902void 1903witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1904{ 1905#ifdef INVARIANT_SUPPORT 1906 struct lock_instance *instance; 1907 struct lock_class *class; 1908 1909 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1910 return; 1911 class = LOCK_CLASS(lock); 1912 if ((class->lc_flags & LC_SLEEPLOCK) != 0) 1913 instance = find_instance(curthread->td_sleeplocks, lock); 1914 else if ((class->lc_flags & LC_SPINLOCK) != 0) 1915 instance = find_instance(PCPU_GET(spinlocks), lock); 1916 else { 1917 panic("Lock (%s) %s is not sleep or spin!", 1918 class->lc_name, lock->lo_name); 1919 } 1920 file = fixup_filename(file); 1921 switch (flags) { 1922 case LA_UNLOCKED: 1923 if (instance != NULL) 1924 panic("Lock (%s) %s locked @ %s:%d.", 1925 class->lc_name, lock->lo_name, file, line); 1926 break; 1927 case LA_LOCKED: 1928 case LA_LOCKED | LA_RECURSED: 1929 case LA_LOCKED | LA_NOTRECURSED: 1930 case LA_SLOCKED: 1931 case LA_SLOCKED | LA_RECURSED: 1932 case LA_SLOCKED | LA_NOTRECURSED: 1933 case LA_XLOCKED: 1934 case LA_XLOCKED | LA_RECURSED: 1935 case LA_XLOCKED | LA_NOTRECURSED: 1936 if (instance == NULL) { 1937 panic("Lock (%s) %s not locked @ %s:%d.", 1938 class->lc_name, lock->lo_name, file, line); 1939 break; 1940 } 1941 if ((flags & LA_XLOCKED) != 0 && 1942 (instance->li_flags & LI_EXCLUSIVE) == 0) 1943 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1944 class->lc_name, lock->lo_name, file, line); 1945 if ((flags & LA_SLOCKED) != 0 && 1946 (instance->li_flags & LI_EXCLUSIVE) != 0) 1947 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1948 class->lc_name, lock->lo_name, file, line); 1949 if ((flags & LA_RECURSED) != 0 && 1950 (instance->li_flags & LI_RECURSEMASK) == 0) 1951 panic("Lock (%s) %s not recursed @ %s:%d.", 1952 class->lc_name, lock->lo_name, file, line); 1953 if ((flags & LA_NOTRECURSED) != 0 && 1954 (instance->li_flags & LI_RECURSEMASK) != 0) 1955 panic("Lock (%s) %s recursed @ %s:%d.", 1956 class->lc_name, lock->lo_name, file, line); 1957 break; 1958 default: 1959 panic("Invalid lock assertion at %s:%d.", file, line); 1960 1961 } 1962#endif /* INVARIANT_SUPPORT */ 1963} 1964 1965#ifdef DDB 1966static void 1967witness_list(struct thread *td) 1968{ 1969 1970 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1971 KASSERT(kdb_active, ("%s: not in the debugger", __func__)); 1972 1973 if (witness_watch == 0) 1974 return; 1975 1976 witness_list_locks(&td->td_sleeplocks); 1977 1978 /* 1979 * We only handle spinlocks if td == curthread. This is somewhat broken 1980 * if td is currently executing on some other CPU and holds spin locks 1981 * as we won't display those locks. If we had a MI way of getting 1982 * the per-cpu data for a given cpu then we could use 1983 * td->td_oncpu to get the list of spinlocks for this thread 1984 * and "fix" this. 1985 * 1986 * That still wouldn't really fix this unless we locked the scheduler 1987 * lock or stopped the other CPU to make sure it wasn't changing the 1988 * list out from under us. It is probably best to just not try to 1989 * handle threads on other CPU's for now. 1990 */ 1991 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1992 witness_list_locks(PCPU_PTR(spinlocks)); 1993} 1994 1995DB_SHOW_COMMAND(locks, db_witness_list) 1996{ 1997 struct thread *td; 1998 1999 if (have_addr) 2000 td = db_lookup_thread(addr, TRUE); 2001 else 2002 td = kdb_thread; 2003 witness_list(td); 2004} 2005 2006DB_SHOW_COMMAND(alllocks, db_witness_list_all) 2007{ 2008 struct thread *td; 2009 struct proc *p; 2010 2011 /* 2012 * It would be nice to list only threads and processes that actually 2013 * held sleep locks, but that information is currently not exported 2014 * by WITNESS. 2015 */ 2016 FOREACH_PROC_IN_SYSTEM(p) { 2017 if (!witness_proc_has_locks(p)) 2018 continue; 2019 FOREACH_THREAD_IN_PROC(p, td) { 2020 if (!witness_thread_has_locks(td)) 2021 continue; 2022 db_printf("Process %d (%s) thread %p (%d)\n", p->p_pid, 2023 td->td_name, td, td->td_tid); 2024 witness_list(td); 2025 } 2026 } 2027} 2028 2029DB_SHOW_COMMAND(witness, db_witness_display) 2030{ 2031 2032 witness_display(db_printf); 2033} 2034#endif 2035