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