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