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