Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_witness.c
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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_rw }, 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_rw }, 331 { "udpinp", &lock_class_rw }, 332 { "so_snd", &lock_class_mtx_sleep }, 333 { NULL, NULL }, 334 /* 335 * TCP/IP 336 */ 337 { "tcp", &lock_class_rw }, 338 { "tcpinp", &lock_class_rw }, 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 { "scrlock", &lock_class_mtx_spin }, 408 #ifdef __i386__ 409 { "cy", &lock_class_mtx_spin }, 410 #endif 411 #ifdef __sparc64__ 412 { "pcib_mtx", &lock_class_mtx_spin }, 413 { "rtc_mtx", &lock_class_mtx_spin }, 414 #endif 415 { "scc_hwmtx", &lock_class_mtx_spin }, 416 { "uart_hwmtx", &lock_class_mtx_spin }, 417 { "fast_taskqueue", &lock_class_mtx_spin }, 418 { "intr table", &lock_class_mtx_spin }, 419 #ifdef HWPMC_HOOKS 420 { "pmc-per-proc", &lock_class_mtx_spin }, 421 #endif 422 { "process slock", &lock_class_mtx_spin }, 423 { "sleepq chain", &lock_class_mtx_spin }, 424 { "umtx lock", &lock_class_mtx_spin }, 425 { "turnstile chain", &lock_class_mtx_spin }, 426 { "turnstile lock", &lock_class_mtx_spin }, 427 { "sched lock", &lock_class_mtx_spin }, 428 { "td_contested", &lock_class_mtx_spin }, 429 { "callout", &lock_class_mtx_spin }, 430 { "entropy harvest mutex", &lock_class_mtx_spin }, 431 { "syscons video lock", &lock_class_mtx_spin }, 432 { "time lock", &lock_class_mtx_spin }, 433 #ifdef SMP 434 { "smp rendezvous", &lock_class_mtx_spin }, 435 #endif 436 /* 437 * leaf locks 438 */ 439 { "icu", &lock_class_mtx_spin }, 440 #if defined(SMP) && defined(__sparc64__) 441 { "ipi", &lock_class_mtx_spin }, 442 #endif 443 #ifdef __i386__ 444 { "allpmaps", &lock_class_mtx_spin }, 445 { "descriptor tables", &lock_class_mtx_spin }, 446 #endif 447 { "clk", &lock_class_mtx_spin }, 448 { "mprof lock", &lock_class_mtx_spin }, 449 { "kse lock", &lock_class_mtx_spin }, 450 { "zombie lock", &lock_class_mtx_spin }, 451 { "ALD Queue", &lock_class_mtx_spin }, 452 #ifdef __ia64__ 453 { "MCA spin lock", &lock_class_mtx_spin }, 454 #endif 455 #if defined(__i386__) || defined(__amd64__) 456 { "pcicfg", &lock_class_mtx_spin }, 457 { "NDIS thread lock", &lock_class_mtx_spin }, 458 #endif 459 { "tw_osl_io_lock", &lock_class_mtx_spin }, 460 { "tw_osl_q_lock", &lock_class_mtx_spin }, 461 { "tw_cl_io_lock", &lock_class_mtx_spin }, 462 { "tw_cl_intr_lock", &lock_class_mtx_spin }, 463 { "tw_cl_gen_lock", &lock_class_mtx_spin }, 464 #ifdef HWPMC_HOOKS 465 { "pmc-leaf", &lock_class_mtx_spin }, 466 #endif 467 { "blocked lock", &lock_class_mtx_spin }, 468 { NULL, NULL }, 469 { NULL, NULL } 470 }; 471 472 #ifdef BLESSING 473 /* 474 * Pairs of locks which have been blessed 475 * Don't complain about order problems with blessed locks 476 */ 477 static struct witness_blessed blessed_list[] = { 478 }; 479 static int blessed_count = 480 sizeof(blessed_list) / sizeof(struct witness_blessed); 481 #endif 482 483 /* 484 * List of locks initialized prior to witness being initialized whose 485 * enrollment is currently deferred. 486 */ 487 STAILQ_HEAD(, lock_object) pending_locks = 488 STAILQ_HEAD_INITIALIZER(pending_locks); 489 490 /* 491 * This global is set to 0 once it becomes safe to use the witness code. 492 */ 493 static int witness_cold = 1; 494 495 /* 496 * This global is set to 1 once the static lock orders have been enrolled 497 * so that a warning can be issued for any spin locks enrolled later. 498 */ 499 static int witness_spin_warn = 0; 500 501 /* 502 * The WITNESS-enabled diagnostic code. Note that the witness code does 503 * assume that the early boot is single-threaded at least until after this 504 * routine is completed. 505 */ 506 static void 507 witness_initialize(void *dummy __unused) 508 { 509 struct lock_object *lock; 510 struct witness_order_list_entry *order; 511 struct witness *w, *w1; 512 int i; 513 514 /* 515 * We have to release Giant before initializing its witness 516 * structure so that WITNESS doesn't get confused. 517 */ 518 mtx_unlock(&Giant); 519 mtx_assert(&Giant, MA_NOTOWNED); 520 521 CTR1(KTR_WITNESS, "%s: initializing witness", __func__); 522 mtx_init(&w_mtx, "witness lock", NULL, MTX_SPIN | MTX_QUIET | 523 MTX_NOWITNESS | MTX_NOPROFILE); 524 for (i = 0; i < WITNESS_COUNT; i++) 525 witness_free(&w_data[i]); 526 for (i = 0; i < WITNESS_CHILDCOUNT; i++) 527 witness_child_free(&w_childdata[i]); 528 for (i = 0; i < LOCK_CHILDCOUNT; i++) 529 witness_lock_list_free(&w_locklistdata[i]); 530 531 /* First add in all the specified order lists. */ 532 for (order = order_lists; order->w_name != NULL; order++) { 533 w = enroll(order->w_name, order->w_class); 534 if (w == NULL) 535 continue; 536 w->w_file = "order list"; 537 for (order++; order->w_name != NULL; order++) { 538 w1 = enroll(order->w_name, order->w_class); 539 if (w1 == NULL) 540 continue; 541 w1->w_file = "order list"; 542 if (!itismychild(w, w1)) 543 panic("Not enough memory for static orders!"); 544 w = w1; 545 } 546 } 547 witness_spin_warn = 1; 548 549 /* Iterate through all locks and add them to witness. */ 550 while (!STAILQ_EMPTY(&pending_locks)) { 551 lock = STAILQ_FIRST(&pending_locks); 552 STAILQ_REMOVE_HEAD(&pending_locks, lo_list); 553 KASSERT(lock->lo_flags & LO_WITNESS, 554 ("%s: lock %s is on pending list but not LO_WITNESS", 555 __func__, lock->lo_name)); 556 lock->lo_witness = enroll(lock->lo_type, LOCK_CLASS(lock)); 557 } 558 559 /* Mark the witness code as being ready for use. */ 560 witness_cold = 0; 561 562 mtx_lock(&Giant); 563 } 564 SYSINIT(witness_init, SI_SUB_WITNESS, SI_ORDER_FIRST, witness_initialize, 565 NULL); 566 567 static int 568 sysctl_debug_witness_watch(SYSCTL_HANDLER_ARGS) 569 { 570 int error, value; 571 572 value = witness_watch; 573 error = sysctl_handle_int(oidp, &value, 0, req); 574 if (error != 0 || req->newptr == NULL) 575 return (error); 576 if (value == witness_watch) 577 return (0); 578 if (value != 0) 579 return (EINVAL); 580 witness_watch = 0; 581 return (0); 582 } 583 584 void 585 witness_init(struct lock_object *lock) 586 { 587 struct lock_class *class; 588 589 /* Various sanity checks. */ 590 class = LOCK_CLASS(lock); 591 if ((lock->lo_flags & LO_RECURSABLE) != 0 && 592 (class->lc_flags & LC_RECURSABLE) == 0) 593 panic("%s: lock (%s) %s can not be recursable", __func__, 594 class->lc_name, lock->lo_name); 595 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 596 (class->lc_flags & LC_SLEEPABLE) == 0) 597 panic("%s: lock (%s) %s can not be sleepable", __func__, 598 class->lc_name, lock->lo_name); 599 if ((lock->lo_flags & LO_UPGRADABLE) != 0 && 600 (class->lc_flags & LC_UPGRADABLE) == 0) 601 panic("%s: lock (%s) %s can not be upgradable", __func__, 602 class->lc_name, lock->lo_name); 603 604 /* 605 * If we shouldn't watch this lock, then just clear lo_witness. 606 * Otherwise, if witness_cold is set, then it is too early to 607 * enroll this lock, so defer it to witness_initialize() by adding 608 * it to the pending_locks list. If it is not too early, then enroll 609 * the lock now. 610 */ 611 if (witness_watch == 0 || panicstr != NULL || 612 (lock->lo_flags & LO_WITNESS) == 0) 613 lock->lo_witness = NULL; 614 else if (witness_cold) { 615 STAILQ_INSERT_TAIL(&pending_locks, lock, lo_list); 616 lock->lo_flags |= LO_ENROLLPEND; 617 } else 618 lock->lo_witness = enroll(lock->lo_type, class); 619 } 620 621 void 622 witness_destroy(struct lock_object *lock) 623 { 624 struct lock_class *class; 625 struct witness *w; 626 627 class = LOCK_CLASS(lock); 628 if (witness_cold) 629 panic("lock (%s) %s destroyed while witness_cold", 630 class->lc_name, lock->lo_name); 631 632 /* XXX: need to verify that no one holds the lock */ 633 if ((lock->lo_flags & (LO_WITNESS | LO_ENROLLPEND)) == LO_WITNESS && 634 lock->lo_witness != NULL) { 635 w = lock->lo_witness; 636 mtx_lock_spin(&w_mtx); 637 MPASS(w->w_refcount > 0); 638 w->w_refcount--; 639 640 /* 641 * Lock is already released if we have an allocation failure 642 * and depart() fails. 643 */ 644 if (w->w_refcount != 0 || depart(w)) 645 mtx_unlock_spin(&w_mtx); 646 } 647 648 /* 649 * If this lock is destroyed before witness is up and running, 650 * remove it from the pending list. 651 */ 652 if (lock->lo_flags & LO_ENROLLPEND) { 653 STAILQ_REMOVE(&pending_locks, lock, lock_object, lo_list); 654 lock->lo_flags &= ~LO_ENROLLPEND; 655 } 656 } 657 658 #ifdef DDB 659 static void 660 witness_levelall (void) 661 { 662 struct witness_list *list; 663 struct witness *w, *w1; 664 665 /* 666 * First clear all levels. 667 */ 668 STAILQ_FOREACH(w, &w_all, w_list) { 669 w->w_level = 0; 670 } 671 672 /* 673 * Look for locks with no parent and level all their descendants. 674 */ 675 STAILQ_FOREACH(w, &w_all, w_list) { 676 /* 677 * This is just an optimization, technically we could get 678 * away just walking the all list each time. 679 */ 680 if (w->w_class->lc_flags & LC_SLEEPLOCK) 681 list = &w_sleep; 682 else 683 list = &w_spin; 684 STAILQ_FOREACH(w1, list, w_typelist) { 685 if (isitmychild(w1, w)) 686 goto skip; 687 } 688 witness_leveldescendents(w, 0); 689 skip: 690 ; /* silence GCC 3.x */ 691 } 692 } 693 694 static void 695 witness_leveldescendents(struct witness *parent, int level) 696 { 697 struct witness_child_list_entry *wcl; 698 int i; 699 700 if (parent->w_level < level) 701 parent->w_level = level; 702 level++; 703 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 704 for (i = 0; i < wcl->wcl_count; i++) 705 witness_leveldescendents(wcl->wcl_children[i], level); 706 } 707 708 static void 709 witness_displaydescendants(void(*prnt)(const char *fmt, ...), 710 struct witness *parent, int indent) 711 { 712 struct witness_child_list_entry *wcl; 713 int i, level; 714 715 level = parent->w_level; 716 prnt("%-2d", level); 717 for (i = 0; i < indent; i++) 718 prnt(" "); 719 if (parent->w_refcount > 0) 720 prnt("%s", parent->w_name); 721 else 722 prnt("(dead)"); 723 if (parent->w_displayed) { 724 prnt(" -- (already displayed)\n"); 725 return; 726 } 727 parent->w_displayed = 1; 728 if (parent->w_refcount > 0) { 729 if (parent->w_file != NULL) 730 prnt(" -- last acquired @ %s:%d", parent->w_file, 731 parent->w_line); 732 } 733 prnt("\n"); 734 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) 735 for (i = 0; i < wcl->wcl_count; i++) 736 witness_displaydescendants(prnt, 737 wcl->wcl_children[i], indent + 1); 738 } 739 740 static void 741 witness_display_list(void(*prnt)(const char *fmt, ...), 742 struct witness_list *list) 743 { 744 struct witness *w; 745 746 STAILQ_FOREACH(w, list, w_typelist) { 747 if (w->w_file == NULL || w->w_level > 0) 748 continue; 749 /* 750 * This lock has no anscestors, display its descendants. 751 */ 752 witness_displaydescendants(prnt, w, 0); 753 } 754 } 755 756 static void 757 witness_display(void(*prnt)(const char *fmt, ...)) 758 { 759 struct witness *w; 760 761 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 762 witness_levelall(); 763 764 /* Clear all the displayed flags. */ 765 STAILQ_FOREACH(w, &w_all, w_list) { 766 w->w_displayed = 0; 767 } 768 769 /* 770 * First, handle sleep locks which have been acquired at least 771 * once. 772 */ 773 prnt("Sleep locks:\n"); 774 witness_display_list(prnt, &w_sleep); 775 776 /* 777 * Now do spin locks which have been acquired at least once. 778 */ 779 prnt("\nSpin locks:\n"); 780 witness_display_list(prnt, &w_spin); 781 782 /* 783 * Finally, any locks which have not been acquired yet. 784 */ 785 prnt("\nLocks which were never acquired:\n"); 786 STAILQ_FOREACH(w, &w_all, w_list) { 787 if (w->w_file != NULL || w->w_refcount == 0) 788 continue; 789 prnt("%s\n", w->w_name); 790 } 791 } 792 #endif /* DDB */ 793 794 /* Trim useless garbage from filenames. */ 795 static const char * 796 fixup_filename(const char *file) 797 { 798 799 if (file == NULL) 800 return (NULL); 801 while (strncmp(file, "../", 3) == 0) 802 file += 3; 803 return (file); 804 } 805 806 int 807 witness_defineorder(struct lock_object *lock1, struct lock_object *lock2) 808 { 809 810 if (witness_watch == 0 || panicstr != NULL) 811 return (0); 812 813 /* Require locks that witness knows about. */ 814 if (lock1 == NULL || lock1->lo_witness == NULL || lock2 == NULL || 815 lock2->lo_witness == NULL) 816 return (EINVAL); 817 818 MPASS(!mtx_owned(&w_mtx)); 819 mtx_lock_spin(&w_mtx); 820 821 /* 822 * If we already have either an explicit or implied lock order that 823 * is the other way around, then return an error. 824 */ 825 if (isitmydescendant(lock2->lo_witness, lock1->lo_witness)) { 826 mtx_unlock_spin(&w_mtx); 827 return (EDOOFUS); 828 } 829 830 /* Try to add the new order. */ 831 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 832 lock2->lo_type, lock1->lo_type); 833 if (!itismychild(lock1->lo_witness, lock2->lo_witness)) 834 return (ENOMEM); 835 mtx_unlock_spin(&w_mtx); 836 return (0); 837 } 838 839 void 840 witness_checkorder(struct lock_object *lock, int flags, const char *file, 841 int line) 842 { 843 struct lock_list_entry **lock_list, *lle; 844 struct lock_instance *lock1, *lock2; 845 struct lock_class *class; 846 struct witness *w, *w1; 847 struct thread *td; 848 int i, j; 849 850 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 851 panicstr != NULL) 852 return; 853 854 /* 855 * Try locks do not block if they fail to acquire the lock, thus 856 * there is no danger of deadlocks or of switching while holding a 857 * spin lock if we acquire a lock via a try operation. This 858 * function shouldn't even be called for try locks, so panic if 859 * that happens. 860 */ 861 if (flags & LOP_TRYLOCK) 862 panic("%s should not be called for try lock operations", 863 __func__); 864 865 w = lock->lo_witness; 866 class = LOCK_CLASS(lock); 867 td = curthread; 868 file = fixup_filename(file); 869 870 if (class->lc_flags & LC_SLEEPLOCK) { 871 /* 872 * Since spin locks include a critical section, this check 873 * implicitly enforces a lock order of all sleep locks before 874 * all spin locks. 875 */ 876 if (td->td_critnest != 0 && !kdb_active) 877 panic("blockable sleep lock (%s) %s @ %s:%d", 878 class->lc_name, lock->lo_name, file, line); 879 880 /* 881 * If this is the first lock acquired then just return as 882 * no order checking is needed. 883 */ 884 if (td->td_sleeplocks == NULL) 885 return; 886 lock_list = &td->td_sleeplocks; 887 } else { 888 /* 889 * If this is the first lock, just return as no order 890 * checking is needed. We check this in both if clauses 891 * here as unifying the check would require us to use a 892 * critical section to ensure we don't migrate while doing 893 * the check. Note that if this is not the first lock, we 894 * are already in a critical section and are safe for the 895 * rest of the check. 896 */ 897 if (PCPU_GET(spinlocks) == NULL) 898 return; 899 lock_list = PCPU_PTR(spinlocks); 900 } 901 902 /* 903 * Check to see if we are recursing on a lock we already own. If 904 * so, make sure that we don't mismatch exclusive and shared lock 905 * acquires. 906 */ 907 lock1 = find_instance(*lock_list, lock); 908 if (lock1 != NULL) { 909 if ((lock1->li_flags & LI_EXCLUSIVE) != 0 && 910 (flags & LOP_EXCLUSIVE) == 0) { 911 printf("shared lock of (%s) %s @ %s:%d\n", 912 class->lc_name, lock->lo_name, file, line); 913 printf("while exclusively locked from %s:%d\n", 914 lock1->li_file, lock1->li_line); 915 panic("share->excl"); 916 } 917 if ((lock1->li_flags & LI_EXCLUSIVE) == 0 && 918 (flags & LOP_EXCLUSIVE) != 0) { 919 printf("exclusive lock of (%s) %s @ %s:%d\n", 920 class->lc_name, lock->lo_name, file, line); 921 printf("while share locked from %s:%d\n", 922 lock1->li_file, lock1->li_line); 923 panic("excl->share"); 924 } 925 return; 926 } 927 928 /* 929 * Try locks do not block if they fail to acquire the lock, thus 930 * there is no danger of deadlocks or of switching while holding a 931 * spin lock if we acquire a lock via a try operation. 932 */ 933 if (flags & LOP_TRYLOCK) 934 return; 935 936 /* 937 * Check for duplicate locks of the same type. Note that we only 938 * have to check for this on the last lock we just acquired. Any 939 * other cases will be caught as lock order violations. 940 */ 941 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 942 w1 = lock1->li_lock->lo_witness; 943 if (w1 == w) { 944 if (w->w_same_squawked || (lock->lo_flags & LO_DUPOK) || 945 (flags & LOP_DUPOK)) 946 return; 947 w->w_same_squawked = 1; 948 printf("acquiring duplicate lock of same type: \"%s\"\n", 949 lock->lo_type); 950 printf(" 1st %s @ %s:%d\n", lock1->li_lock->lo_name, 951 lock1->li_file, lock1->li_line); 952 printf(" 2nd %s @ %s:%d\n", lock->lo_name, file, line); 953 #ifdef KDB 954 goto debugger; 955 #else 956 return; 957 #endif 958 } 959 MPASS(!mtx_owned(&w_mtx)); 960 mtx_lock_spin(&w_mtx); 961 /* 962 * If we know that the the lock we are acquiring comes after 963 * the lock we most recently acquired in the lock order tree, 964 * then there is no need for any further checks. 965 */ 966 if (isitmychild(w1, w)) { 967 mtx_unlock_spin(&w_mtx); 968 return; 969 } 970 for (j = 0, lle = *lock_list; lle != NULL; lle = lle->ll_next) { 971 for (i = lle->ll_count - 1; i >= 0; i--, j++) { 972 973 MPASS(j < WITNESS_COUNT); 974 lock1 = &lle->ll_children[i]; 975 w1 = lock1->li_lock->lo_witness; 976 977 /* 978 * If this lock doesn't undergo witness checking, 979 * then skip it. 980 */ 981 if (w1 == NULL) { 982 KASSERT((lock1->li_lock->lo_flags & LO_WITNESS) == 0, 983 ("lock missing witness structure")); 984 continue; 985 } 986 /* 987 * If we are locking Giant and this is a sleepable 988 * lock, then skip it. 989 */ 990 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0 && 991 lock == &Giant.lock_object) 992 continue; 993 /* 994 * If we are locking a sleepable lock and this lock 995 * is Giant, then skip it. 996 */ 997 if ((lock->lo_flags & LO_SLEEPABLE) != 0 && 998 lock1->li_lock == &Giant.lock_object) 999 continue; 1000 /* 1001 * If we are locking a sleepable lock and this lock 1002 * isn't sleepable, we want to treat it as a lock 1003 * order violation to enfore a general lock order of 1004 * sleepable locks before non-sleepable locks. 1005 */ 1006 if (((lock->lo_flags & LO_SLEEPABLE) != 0 && 1007 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 1008 goto reversal; 1009 /* 1010 * If we are locking Giant and this is a non-sleepable 1011 * lock, then treat it as a reversal. 1012 */ 1013 if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 && 1014 lock == &Giant.lock_object) 1015 goto reversal; 1016 /* 1017 * Check the lock order hierarchy for a reveresal. 1018 */ 1019 if (!isitmydescendant(w, w1)) 1020 continue; 1021 reversal: 1022 /* 1023 * We have a lock order violation, check to see if it 1024 * is allowed or has already been yelled about. 1025 */ 1026 mtx_unlock_spin(&w_mtx); 1027 #ifdef BLESSING 1028 /* 1029 * If the lock order is blessed, just bail. We don't 1030 * look for other lock order violations though, which 1031 * may be a bug. 1032 */ 1033 if (blessed(w, w1)) 1034 return; 1035 #endif 1036 if (lock1->li_lock == &Giant.lock_object) { 1037 if (w1->w_Giant_squawked) 1038 return; 1039 else 1040 w1->w_Giant_squawked = 1; 1041 } else { 1042 if (w1->w_other_squawked) 1043 return; 1044 else 1045 w1->w_other_squawked = 1; 1046 } 1047 /* 1048 * Ok, yell about it. 1049 */ 1050 if (((lock->lo_flags & LO_SLEEPABLE) != 0 && 1051 (lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0)) 1052 printf( 1053 "lock order reversal: (sleepable after non-sleepable)\n"); 1054 else if ((lock1->li_lock->lo_flags & LO_SLEEPABLE) == 0 1055 && lock == &Giant.lock_object) 1056 printf( 1057 "lock order reversal: (Giant after non-sleepable)\n"); 1058 else 1059 printf("lock order reversal:\n"); 1060 /* 1061 * Try to locate an earlier lock with 1062 * witness w in our list. 1063 */ 1064 do { 1065 lock2 = &lle->ll_children[i]; 1066 MPASS(lock2->li_lock != NULL); 1067 if (lock2->li_lock->lo_witness == w) 1068 break; 1069 if (i == 0 && lle->ll_next != NULL) { 1070 lle = lle->ll_next; 1071 i = lle->ll_count - 1; 1072 MPASS(i >= 0 && i < LOCK_NCHILDREN); 1073 } else 1074 i--; 1075 } while (i >= 0); 1076 if (i < 0) { 1077 printf(" 1st %p %s (%s) @ %s:%d\n", 1078 lock1->li_lock, lock1->li_lock->lo_name, 1079 lock1->li_lock->lo_type, lock1->li_file, 1080 lock1->li_line); 1081 printf(" 2nd %p %s (%s) @ %s:%d\n", lock, 1082 lock->lo_name, lock->lo_type, file, line); 1083 } else { 1084 printf(" 1st %p %s (%s) @ %s:%d\n", 1085 lock2->li_lock, lock2->li_lock->lo_name, 1086 lock2->li_lock->lo_type, lock2->li_file, 1087 lock2->li_line); 1088 printf(" 2nd %p %s (%s) @ %s:%d\n", 1089 lock1->li_lock, lock1->li_lock->lo_name, 1090 lock1->li_lock->lo_type, lock1->li_file, 1091 lock1->li_line); 1092 printf(" 3rd %p %s (%s) @ %s:%d\n", lock, 1093 lock->lo_name, lock->lo_type, file, line); 1094 } 1095 #ifdef KDB 1096 goto debugger; 1097 #else 1098 return; 1099 #endif 1100 } 1101 } 1102 lock1 = &(*lock_list)->ll_children[(*lock_list)->ll_count - 1]; 1103 /* 1104 * If requested, build a new lock order. However, don't build a new 1105 * relationship between a sleepable lock and Giant if it is in the 1106 * wrong direction. The correct lock order is that sleepable locks 1107 * always come before Giant. 1108 */ 1109 if (flags & LOP_NEWORDER && 1110 !(lock1->li_lock == &Giant.lock_object && 1111 (lock->lo_flags & LO_SLEEPABLE) != 0)) { 1112 CTR3(KTR_WITNESS, "%s: adding %s as a child of %s", __func__, 1113 lock->lo_type, lock1->li_lock->lo_type); 1114 if (!itismychild(lock1->li_lock->lo_witness, w)) 1115 /* Witness is dead. */ 1116 return; 1117 } 1118 mtx_unlock_spin(&w_mtx); 1119 return; 1120 1121 #ifdef KDB 1122 debugger: 1123 if (witness_trace) 1124 kdb_backtrace(); 1125 if (witness_kdb) 1126 kdb_enter_why(KDB_WHY_WITNESS, __func__); 1127 #endif 1128 } 1129 1130 void 1131 witness_lock(struct lock_object *lock, int flags, const char *file, int line) 1132 { 1133 struct lock_list_entry **lock_list, *lle; 1134 struct lock_instance *instance; 1135 struct witness *w; 1136 struct thread *td; 1137 1138 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1139 panicstr != NULL) 1140 return; 1141 w = lock->lo_witness; 1142 td = curthread; 1143 file = fixup_filename(file); 1144 1145 /* Determine lock list for this lock. */ 1146 if (LOCK_CLASS(lock)->lc_flags & LC_SLEEPLOCK) 1147 lock_list = &td->td_sleeplocks; 1148 else 1149 lock_list = PCPU_PTR(spinlocks); 1150 1151 /* Check to see if we are recursing on a lock we already own. */ 1152 instance = find_instance(*lock_list, lock); 1153 if (instance != NULL) { 1154 instance->li_flags++; 1155 CTR4(KTR_WITNESS, "%s: pid %d recursed on %s r=%d", __func__, 1156 td->td_proc->p_pid, lock->lo_name, 1157 instance->li_flags & LI_RECURSEMASK); 1158 instance->li_file = file; 1159 instance->li_line = line; 1160 return; 1161 } 1162 1163 /* Update per-witness last file and line acquire. */ 1164 w->w_file = file; 1165 w->w_line = line; 1166 1167 /* Find the next open lock instance in the list and fill it. */ 1168 lle = *lock_list; 1169 if (lle == NULL || lle->ll_count == LOCK_NCHILDREN) { 1170 lle = witness_lock_list_get(); 1171 if (lle == NULL) 1172 return; 1173 lle->ll_next = *lock_list; 1174 CTR3(KTR_WITNESS, "%s: pid %d added lle %p", __func__, 1175 td->td_proc->p_pid, lle); 1176 *lock_list = lle; 1177 } 1178 instance = &lle->ll_children[lle->ll_count++]; 1179 instance->li_lock = lock; 1180 instance->li_line = line; 1181 instance->li_file = file; 1182 if ((flags & LOP_EXCLUSIVE) != 0) 1183 instance->li_flags = LI_EXCLUSIVE; 1184 else 1185 instance->li_flags = 0; 1186 CTR4(KTR_WITNESS, "%s: pid %d added %s as lle[%d]", __func__, 1187 td->td_proc->p_pid, lock->lo_name, lle->ll_count - 1); 1188 } 1189 1190 void 1191 witness_upgrade(struct lock_object *lock, int flags, const char *file, int line) 1192 { 1193 struct lock_instance *instance; 1194 struct lock_class *class; 1195 1196 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1197 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1198 return; 1199 class = LOCK_CLASS(lock); 1200 file = fixup_filename(file); 1201 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1202 panic("upgrade of non-upgradable lock (%s) %s @ %s:%d", 1203 class->lc_name, lock->lo_name, file, line); 1204 if ((flags & LOP_TRYLOCK) == 0) 1205 panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name, 1206 lock->lo_name, file, line); 1207 if ((class->lc_flags & LC_SLEEPLOCK) == 0) 1208 panic("upgrade 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("upgrade 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("upgrade of exclusive lock (%s) %s @ %s:%d", 1216 class->lc_name, lock->lo_name, file, line); 1217 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1218 panic("upgrade 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_downgrade(struct lock_object *lock, int flags, const char *file, 1226 int line) 1227 { 1228 struct lock_instance *instance; 1229 struct lock_class *class; 1230 1231 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1232 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1233 return; 1234 class = LOCK_CLASS(lock); 1235 file = fixup_filename(file); 1236 if ((lock->lo_flags & LO_UPGRADABLE) == 0) 1237 panic("downgrade of non-upgradable lock (%s) %s @ %s:%d", 1238 class->lc_name, lock->lo_name, file, line); 1239 if ((class->lc_flags & LC_SLEEPLOCK) == 0) 1240 panic("downgrade of non-sleep lock (%s) %s @ %s:%d", 1241 class->lc_name, lock->lo_name, file, line); 1242 instance = find_instance(curthread->td_sleeplocks, lock); 1243 if (instance == NULL) 1244 panic("downgrade of unlocked lock (%s) %s @ %s:%d", 1245 class->lc_name, lock->lo_name, file, line); 1246 if ((instance->li_flags & LI_EXCLUSIVE) == 0) 1247 panic("downgrade of shared lock (%s) %s @ %s:%d", 1248 class->lc_name, lock->lo_name, file, line); 1249 if ((instance->li_flags & LI_RECURSEMASK) != 0) 1250 panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d", 1251 class->lc_name, lock->lo_name, 1252 instance->li_flags & LI_RECURSEMASK, file, line); 1253 instance->li_flags &= ~LI_EXCLUSIVE; 1254 } 1255 1256 void 1257 witness_unlock(struct lock_object *lock, int flags, const char *file, int line) 1258 { 1259 struct lock_list_entry **lock_list, *lle; 1260 struct lock_instance *instance; 1261 struct lock_class *class; 1262 struct thread *td; 1263 register_t s; 1264 int i, j; 1265 1266 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL || 1267 panicstr != NULL) 1268 return; 1269 td = curthread; 1270 class = LOCK_CLASS(lock); 1271 file = fixup_filename(file); 1272 1273 /* Find lock instance associated with this lock. */ 1274 if (class->lc_flags & LC_SLEEPLOCK) 1275 lock_list = &td->td_sleeplocks; 1276 else 1277 lock_list = PCPU_PTR(spinlocks); 1278 for (; *lock_list != NULL; lock_list = &(*lock_list)->ll_next) 1279 for (i = 0; i < (*lock_list)->ll_count; i++) { 1280 instance = &(*lock_list)->ll_children[i]; 1281 if (instance->li_lock == lock) 1282 goto found; 1283 } 1284 panic("lock (%s) %s not locked @ %s:%d", class->lc_name, lock->lo_name, 1285 file, line); 1286 found: 1287 1288 /* First, check for shared/exclusive mismatches. */ 1289 if ((instance->li_flags & LI_EXCLUSIVE) != 0 && 1290 (flags & LOP_EXCLUSIVE) == 0) { 1291 printf("shared unlock of (%s) %s @ %s:%d\n", class->lc_name, 1292 lock->lo_name, file, line); 1293 printf("while exclusively locked from %s:%d\n", 1294 instance->li_file, instance->li_line); 1295 panic("excl->ushare"); 1296 } 1297 if ((instance->li_flags & LI_EXCLUSIVE) == 0 && 1298 (flags & LOP_EXCLUSIVE) != 0) { 1299 printf("exclusive unlock of (%s) %s @ %s:%d\n", class->lc_name, 1300 lock->lo_name, file, line); 1301 printf("while share locked from %s:%d\n", instance->li_file, 1302 instance->li_line); 1303 panic("share->uexcl"); 1304 } 1305 1306 /* If we are recursed, unrecurse. */ 1307 if ((instance->li_flags & LI_RECURSEMASK) > 0) { 1308 CTR4(KTR_WITNESS, "%s: pid %d unrecursed on %s r=%d", __func__, 1309 td->td_proc->p_pid, instance->li_lock->lo_name, 1310 instance->li_flags); 1311 instance->li_flags--; 1312 return; 1313 } 1314 1315 /* Otherwise, remove this item from the list. */ 1316 s = intr_disable(); 1317 CTR4(KTR_WITNESS, "%s: pid %d removed %s from lle[%d]", __func__, 1318 td->td_proc->p_pid, instance->li_lock->lo_name, 1319 (*lock_list)->ll_count - 1); 1320 for (j = i; j < (*lock_list)->ll_count - 1; j++) 1321 (*lock_list)->ll_children[j] = 1322 (*lock_list)->ll_children[j + 1]; 1323 (*lock_list)->ll_count--; 1324 intr_restore(s); 1325 1326 /* If this lock list entry is now empty, free it. */ 1327 if ((*lock_list)->ll_count == 0) { 1328 lle = *lock_list; 1329 *lock_list = lle->ll_next; 1330 CTR3(KTR_WITNESS, "%s: pid %d removed lle %p", __func__, 1331 td->td_proc->p_pid, lle); 1332 witness_lock_list_free(lle); 1333 } 1334 } 1335 1336 /* 1337 * Warn if any locks other than 'lock' are held. Flags can be passed in to 1338 * exempt Giant and sleepable locks from the checks as well. If any 1339 * non-exempt locks are held, then a supplied message is printed to the 1340 * console along with a list of the offending locks. If indicated in the 1341 * flags then a failure results in a panic as well. 1342 */ 1343 int 1344 witness_warn(int flags, struct lock_object *lock, const char *fmt, ...) 1345 { 1346 struct lock_list_entry *lle; 1347 struct lock_instance *lock1; 1348 struct thread *td; 1349 va_list ap; 1350 int i, n; 1351 1352 if (witness_cold || witness_watch == 0 || panicstr != NULL) 1353 return (0); 1354 n = 0; 1355 td = curthread; 1356 for (lle = td->td_sleeplocks; lle != NULL; lle = lle->ll_next) 1357 for (i = lle->ll_count - 1; i >= 0; i--) { 1358 lock1 = &lle->ll_children[i]; 1359 if (lock1->li_lock == lock) 1360 continue; 1361 if (flags & WARN_GIANTOK && 1362 lock1->li_lock == &Giant.lock_object) 1363 continue; 1364 if (flags & WARN_SLEEPOK && 1365 (lock1->li_lock->lo_flags & LO_SLEEPABLE) != 0) 1366 continue; 1367 if (n == 0) { 1368 va_start(ap, fmt); 1369 vprintf(fmt, ap); 1370 va_end(ap); 1371 printf(" with the following"); 1372 if (flags & WARN_SLEEPOK) 1373 printf(" non-sleepable"); 1374 printf(" locks held:\n"); 1375 } 1376 n++; 1377 witness_list_lock(lock1); 1378 } 1379 if (PCPU_GET(spinlocks) != NULL) { 1380 /* 1381 * Since we already hold a spinlock preemption is 1382 * already blocked. 1383 */ 1384 if (n == 0) { 1385 va_start(ap, fmt); 1386 vprintf(fmt, ap); 1387 va_end(ap); 1388 printf(" with the following"); 1389 if (flags & WARN_SLEEPOK) 1390 printf(" non-sleepable"); 1391 printf(" locks held:\n"); 1392 } 1393 n += witness_list_locks(PCPU_PTR(spinlocks)); 1394 } 1395 if (flags & WARN_PANIC && n) 1396 panic("witness_warn"); 1397 #ifdef KDB 1398 else if (witness_kdb && n) 1399 kdb_enter_why(KDB_WHY_WITNESS, __func__); 1400 else if (witness_trace && n) 1401 kdb_backtrace(); 1402 #endif 1403 return (n); 1404 } 1405 1406 const char * 1407 witness_file(struct lock_object *lock) 1408 { 1409 struct witness *w; 1410 1411 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1412 return ("?"); 1413 w = lock->lo_witness; 1414 return (w->w_file); 1415 } 1416 1417 int 1418 witness_line(struct lock_object *lock) 1419 { 1420 struct witness *w; 1421 1422 if (witness_cold || witness_watch == 0 || lock->lo_witness == NULL) 1423 return (0); 1424 w = lock->lo_witness; 1425 return (w->w_line); 1426 } 1427 1428 static struct witness * 1429 enroll(const char *description, struct lock_class *lock_class) 1430 { 1431 struct witness *w; 1432 1433 if (witness_watch == 0 || panicstr != NULL) 1434 return (NULL); 1435 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_skipspin) 1436 return (NULL); 1437 mtx_lock_spin(&w_mtx); 1438 STAILQ_FOREACH(w, &w_all, w_list) { 1439 if (w->w_name == description || (w->w_refcount > 0 && 1440 strcmp(description, w->w_name) == 0)) { 1441 w->w_refcount++; 1442 mtx_unlock_spin(&w_mtx); 1443 if (lock_class != w->w_class) 1444 panic( 1445 "lock (%s) %s does not match earlier (%s) lock", 1446 description, lock_class->lc_name, 1447 w->w_class->lc_name); 1448 return (w); 1449 } 1450 } 1451 if ((w = witness_get()) == NULL) 1452 goto out; 1453 w->w_name = description; 1454 w->w_class = lock_class; 1455 w->w_refcount = 1; 1456 STAILQ_INSERT_HEAD(&w_all, w, w_list); 1457 if (lock_class->lc_flags & LC_SPINLOCK) { 1458 STAILQ_INSERT_HEAD(&w_spin, w, w_typelist); 1459 w_spin_cnt++; 1460 } else if (lock_class->lc_flags & LC_SLEEPLOCK) { 1461 STAILQ_INSERT_HEAD(&w_sleep, w, w_typelist); 1462 w_sleep_cnt++; 1463 } else { 1464 mtx_unlock_spin(&w_mtx); 1465 panic("lock class %s is not sleep or spin", 1466 lock_class->lc_name); 1467 } 1468 mtx_unlock_spin(&w_mtx); 1469 out: 1470 /* 1471 * We issue a warning for any spin locks not defined in the static 1472 * order list as a way to discourage their use (folks should really 1473 * be using non-spin mutexes most of the time). However, several 1474 * 3rd part device drivers use spin locks because that is all they 1475 * have available on Windows and Linux and they think that normal 1476 * mutexes are insufficient. 1477 */ 1478 if ((lock_class->lc_flags & LC_SPINLOCK) && witness_spin_warn) 1479 printf("WITNESS: spin lock %s not in order list\n", 1480 description); 1481 return (w); 1482 } 1483 1484 /* Don't let the door bang you on the way out... */ 1485 static int 1486 depart(struct witness *w) 1487 { 1488 struct witness_child_list_entry *wcl, *nwcl; 1489 struct witness_list *list; 1490 struct witness *parent; 1491 1492 MPASS(w->w_refcount == 0); 1493 if (w->w_class->lc_flags & LC_SLEEPLOCK) { 1494 list = &w_sleep; 1495 w_sleep_cnt--; 1496 } else { 1497 list = &w_spin; 1498 w_spin_cnt--; 1499 } 1500 /* 1501 * First, we run through the entire tree looking for any 1502 * witnesses that the outgoing witness is a child of. For 1503 * each parent that we find, we reparent all the direct 1504 * children of the outgoing witness to its parent. 1505 */ 1506 STAILQ_FOREACH(parent, list, w_typelist) { 1507 if (!isitmychild(parent, w)) 1508 continue; 1509 removechild(parent, w); 1510 } 1511 1512 /* 1513 * Now we go through and free up the child list of the 1514 * outgoing witness. 1515 */ 1516 for (wcl = w->w_children; wcl != NULL; wcl = nwcl) { 1517 nwcl = wcl->wcl_next; 1518 w_child_cnt--; 1519 witness_child_free(wcl); 1520 } 1521 1522 /* 1523 * Detach from various lists and free. 1524 */ 1525 STAILQ_REMOVE(list, w, witness, w_typelist); 1526 STAILQ_REMOVE(&w_all, w, witness, w_list); 1527 witness_free(w); 1528 1529 return (1); 1530 } 1531 1532 /* 1533 * Add "child" as a direct child of "parent". Returns false if 1534 * we fail due to out of memory. 1535 */ 1536 static int 1537 insertchild(struct witness *parent, struct witness *child) 1538 { 1539 struct witness_child_list_entry **wcl; 1540 1541 MPASS(child != NULL && parent != NULL); 1542 1543 /* 1544 * Insert "child" after "parent" 1545 */ 1546 wcl = &parent->w_children; 1547 while (*wcl != NULL && (*wcl)->wcl_count == WITNESS_NCHILDREN) 1548 wcl = &(*wcl)->wcl_next; 1549 if (*wcl == NULL) { 1550 *wcl = witness_child_get(); 1551 if (*wcl == NULL) 1552 return (0); 1553 w_child_cnt++; 1554 } 1555 (*wcl)->wcl_children[(*wcl)->wcl_count++] = child; 1556 1557 return (1); 1558 } 1559 1560 1561 static int 1562 itismychild(struct witness *parent, struct witness *child) 1563 { 1564 struct witness_list *list; 1565 1566 MPASS(child != NULL && parent != NULL); 1567 if ((parent->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK)) != 1568 (child->w_class->lc_flags & (LC_SLEEPLOCK | LC_SPINLOCK))) 1569 panic( 1570 "%s: parent (%s) and child (%s) are not the same lock type", 1571 __func__, parent->w_class->lc_name, 1572 child->w_class->lc_name); 1573 1574 if (!insertchild(parent, child)) 1575 return (0); 1576 1577 if (parent->w_class->lc_flags & LC_SLEEPLOCK) 1578 list = &w_sleep; 1579 else 1580 list = &w_spin; 1581 return (1); 1582 } 1583 1584 static void 1585 removechild(struct witness *parent, struct witness *child) 1586 { 1587 struct witness_child_list_entry **wcl, *wcl1; 1588 int i; 1589 1590 for (wcl = &parent->w_children; *wcl != NULL; wcl = &(*wcl)->wcl_next) 1591 for (i = 0; i < (*wcl)->wcl_count; i++) 1592 if ((*wcl)->wcl_children[i] == child) 1593 goto found; 1594 return; 1595 found: 1596 (*wcl)->wcl_count--; 1597 if ((*wcl)->wcl_count > i) 1598 (*wcl)->wcl_children[i] = 1599 (*wcl)->wcl_children[(*wcl)->wcl_count]; 1600 MPASS((*wcl)->wcl_children[i] != NULL); 1601 if ((*wcl)->wcl_count != 0) 1602 return; 1603 wcl1 = *wcl; 1604 *wcl = wcl1->wcl_next; 1605 w_child_cnt--; 1606 witness_child_free(wcl1); 1607 } 1608 1609 static int 1610 isitmychild(struct witness *parent, struct witness *child) 1611 { 1612 struct witness_child_list_entry *wcl; 1613 int i; 1614 1615 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1616 for (i = 0; i < wcl->wcl_count; i++) { 1617 if (wcl->wcl_children[i] == child) 1618 return (1); 1619 } 1620 } 1621 return (0); 1622 } 1623 1624 static int 1625 isitmydescendant(struct witness *parent, struct witness *child) 1626 { 1627 struct witness_child_list_entry *wcl; 1628 int i, j; 1629 1630 if (isitmychild(parent, child)) 1631 return (1); 1632 j = 0; 1633 for (wcl = parent->w_children; wcl != NULL; wcl = wcl->wcl_next) { 1634 MPASS(j < 1000); 1635 for (i = 0; i < wcl->wcl_count; i++) { 1636 if (isitmydescendant(wcl->wcl_children[i], child)) 1637 return (1); 1638 } 1639 j++; 1640 } 1641 return (0); 1642 } 1643 1644 #ifdef BLESSING 1645 static int 1646 blessed(struct witness *w1, struct witness *w2) 1647 { 1648 int i; 1649 struct witness_blessed *b; 1650 1651 for (i = 0; i < blessed_count; i++) { 1652 b = &blessed_list[i]; 1653 if (strcmp(w1->w_name, b->b_lock1) == 0) { 1654 if (strcmp(w2->w_name, b->b_lock2) == 0) 1655 return (1); 1656 continue; 1657 } 1658 if (strcmp(w1->w_name, b->b_lock2) == 0) 1659 if (strcmp(w2->w_name, b->b_lock1) == 0) 1660 return (1); 1661 } 1662 return (0); 1663 } 1664 #endif 1665 1666 static struct witness * 1667 witness_get(void) 1668 { 1669 struct witness *w; 1670 1671 if (witness_watch == 0) { 1672 mtx_unlock_spin(&w_mtx); 1673 return (NULL); 1674 } 1675 if (STAILQ_EMPTY(&w_free)) { 1676 witness_watch = 0; 1677 mtx_unlock_spin(&w_mtx); 1678 printf("%s: witness exhausted\n", __func__); 1679 return (NULL); 1680 } 1681 w = STAILQ_FIRST(&w_free); 1682 STAILQ_REMOVE_HEAD(&w_free, w_list); 1683 w_free_cnt--; 1684 bzero(w, sizeof(*w)); 1685 return (w); 1686 } 1687 1688 static void 1689 witness_free(struct witness *w) 1690 { 1691 1692 STAILQ_INSERT_HEAD(&w_free, w, w_list); 1693 w_free_cnt++; 1694 } 1695 1696 static struct witness_child_list_entry * 1697 witness_child_get(void) 1698 { 1699 struct witness_child_list_entry *wcl; 1700 1701 if (witness_watch == 0) { 1702 mtx_unlock_spin(&w_mtx); 1703 return (NULL); 1704 } 1705 wcl = w_child_free; 1706 if (wcl == NULL) { 1707 witness_watch = 0; 1708 mtx_unlock_spin(&w_mtx); 1709 printf("%s: witness exhausted\n", __func__); 1710 return (NULL); 1711 } 1712 w_child_free = wcl->wcl_next; 1713 w_child_free_cnt--; 1714 bzero(wcl, sizeof(*wcl)); 1715 return (wcl); 1716 } 1717 1718 static void 1719 witness_child_free(struct witness_child_list_entry *wcl) 1720 { 1721 1722 wcl->wcl_next = w_child_free; 1723 w_child_free = wcl; 1724 w_child_free_cnt++; 1725 } 1726 1727 static struct lock_list_entry * 1728 witness_lock_list_get(void) 1729 { 1730 struct lock_list_entry *lle; 1731 1732 if (witness_watch == 0) 1733 return (NULL); 1734 mtx_lock_spin(&w_mtx); 1735 lle = w_lock_list_free; 1736 if (lle == NULL) { 1737 witness_watch = 0; 1738 mtx_unlock_spin(&w_mtx); 1739 printf("%s: witness exhausted\n", __func__); 1740 return (NULL); 1741 } 1742 w_lock_list_free = lle->ll_next; 1743 mtx_unlock_spin(&w_mtx); 1744 bzero(lle, sizeof(*lle)); 1745 return (lle); 1746 } 1747 1748 static void 1749 witness_lock_list_free(struct lock_list_entry *lle) 1750 { 1751 1752 mtx_lock_spin(&w_mtx); 1753 lle->ll_next = w_lock_list_free; 1754 w_lock_list_free = lle; 1755 mtx_unlock_spin(&w_mtx); 1756 } 1757 1758 static struct lock_instance * 1759 find_instance(struct lock_list_entry *lock_list, struct lock_object *lock) 1760 { 1761 struct lock_list_entry *lle; 1762 struct lock_instance *instance; 1763 int i; 1764 1765 for (lle = lock_list; lle != NULL; lle = lle->ll_next) 1766 for (i = lle->ll_count - 1; i >= 0; i--) { 1767 instance = &lle->ll_children[i]; 1768 if (instance->li_lock == lock) 1769 return (instance); 1770 } 1771 return (NULL); 1772 } 1773 1774 static void 1775 witness_list_lock(struct lock_instance *instance) 1776 { 1777 struct lock_object *lock; 1778 1779 lock = instance->li_lock; 1780 printf("%s %s %s", (instance->li_flags & LI_EXCLUSIVE) != 0 ? 1781 "exclusive" : "shared", LOCK_CLASS(lock)->lc_name, lock->lo_name); 1782 if (lock->lo_type != lock->lo_name) 1783 printf(" (%s)", lock->lo_type); 1784 printf(" r = %d (%p) locked @ %s:%d\n", 1785 instance->li_flags & LI_RECURSEMASK, lock, instance->li_file, 1786 instance->li_line); 1787 } 1788 1789 #ifdef DDB 1790 static int 1791 witness_thread_has_locks(struct thread *td) 1792 { 1793 1794 return (td->td_sleeplocks != NULL); 1795 } 1796 1797 static int 1798 witness_proc_has_locks(struct proc *p) 1799 { 1800 struct thread *td; 1801 1802 FOREACH_THREAD_IN_PROC(p, td) { 1803 if (witness_thread_has_locks(td)) 1804 return (1); 1805 } 1806 return (0); 1807 } 1808 #endif 1809 1810 int 1811 witness_list_locks(struct lock_list_entry **lock_list) 1812 { 1813 struct lock_list_entry *lle; 1814 int i, nheld; 1815 1816 nheld = 0; 1817 for (lle = *lock_list; lle != NULL; lle = lle->ll_next) 1818 for (i = lle->ll_count - 1; i >= 0; i--) { 1819 witness_list_lock(&lle->ll_children[i]); 1820 nheld++; 1821 } 1822 return (nheld); 1823 } 1824 1825 /* 1826 * This is a bit risky at best. We call this function when we have timed 1827 * out acquiring a spin lock, and we assume that the other CPU is stuck 1828 * with this lock held. So, we go groveling around in the other CPU's 1829 * per-cpu data to try to find the lock instance for this spin lock to 1830 * see when it was last acquired. 1831 */ 1832 void 1833 witness_display_spinlock(struct lock_object *lock, struct thread *owner) 1834 { 1835 struct lock_instance *instance; 1836 struct pcpu *pc; 1837 1838 if (owner->td_critnest == 0 || owner->td_oncpu == NOCPU) 1839 return; 1840 pc = pcpu_find(owner->td_oncpu); 1841 instance = find_instance(pc->pc_spinlocks, lock); 1842 if (instance != NULL) 1843 witness_list_lock(instance); 1844 } 1845 1846 void 1847 witness_save(struct lock_object *lock, const char **filep, int *linep) 1848 { 1849 struct lock_list_entry *lock_list; 1850 struct lock_instance *instance; 1851 struct lock_class *class; 1852 1853 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1854 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1855 return; 1856 class = LOCK_CLASS(lock); 1857 if (class->lc_flags & LC_SLEEPLOCK) 1858 lock_list = curthread->td_sleeplocks; 1859 else { 1860 if (witness_skipspin) 1861 return; 1862 lock_list = PCPU_GET(spinlocks); 1863 } 1864 instance = find_instance(lock_list, lock); 1865 if (instance == NULL) 1866 panic("%s: lock (%s) %s not locked", __func__, 1867 class->lc_name, lock->lo_name); 1868 *filep = instance->li_file; 1869 *linep = instance->li_line; 1870 } 1871 1872 void 1873 witness_restore(struct lock_object *lock, const char *file, int line) 1874 { 1875 struct lock_list_entry *lock_list; 1876 struct lock_instance *instance; 1877 struct lock_class *class; 1878 1879 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1880 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1881 return; 1882 class = LOCK_CLASS(lock); 1883 if (class->lc_flags & LC_SLEEPLOCK) 1884 lock_list = curthread->td_sleeplocks; 1885 else { 1886 if (witness_skipspin) 1887 return; 1888 lock_list = PCPU_GET(spinlocks); 1889 } 1890 instance = find_instance(lock_list, lock); 1891 if (instance == NULL) 1892 panic("%s: lock (%s) %s not locked", __func__, 1893 class->lc_name, lock->lo_name); 1894 lock->lo_witness->w_file = file; 1895 lock->lo_witness->w_line = line; 1896 instance->li_file = file; 1897 instance->li_line = line; 1898 } 1899 1900 void 1901 witness_assert(struct lock_object *lock, int flags, const char *file, int line) 1902 { 1903 #ifdef INVARIANT_SUPPORT 1904 struct lock_instance *instance; 1905 struct lock_class *class; 1906 1907 if (lock->lo_witness == NULL || witness_watch == 0 || panicstr != NULL) 1908 return; 1909 class = LOCK_CLASS(lock); 1910 if ((class->lc_flags & LC_SLEEPLOCK) != 0) 1911 instance = find_instance(curthread->td_sleeplocks, lock); 1912 else if ((class->lc_flags & LC_SPINLOCK) != 0) 1913 instance = find_instance(PCPU_GET(spinlocks), lock); 1914 else { 1915 panic("Lock (%s) %s is not sleep or spin!", 1916 class->lc_name, lock->lo_name); 1917 } 1918 file = fixup_filename(file); 1919 switch (flags) { 1920 case LA_UNLOCKED: 1921 if (instance != NULL) 1922 panic("Lock (%s) %s locked @ %s:%d.", 1923 class->lc_name, lock->lo_name, file, line); 1924 break; 1925 case LA_LOCKED: 1926 case LA_LOCKED | LA_RECURSED: 1927 case LA_LOCKED | LA_NOTRECURSED: 1928 case LA_SLOCKED: 1929 case LA_SLOCKED | LA_RECURSED: 1930 case LA_SLOCKED | LA_NOTRECURSED: 1931 case LA_XLOCKED: 1932 case LA_XLOCKED | LA_RECURSED: 1933 case LA_XLOCKED | LA_NOTRECURSED: 1934 if (instance == NULL) { 1935 panic("Lock (%s) %s not locked @ %s:%d.", 1936 class->lc_name, lock->lo_name, file, line); 1937 break; 1938 } 1939 if ((flags & LA_XLOCKED) != 0 && 1940 (instance->li_flags & LI_EXCLUSIVE) == 0) 1941 panic("Lock (%s) %s not exclusively locked @ %s:%d.", 1942 class->lc_name, lock->lo_name, file, line); 1943 if ((flags & LA_SLOCKED) != 0 && 1944 (instance->li_flags & LI_EXCLUSIVE) != 0) 1945 panic("Lock (%s) %s exclusively locked @ %s:%d.", 1946 class->lc_name, lock->lo_name, file, line); 1947 if ((flags & LA_RECURSED) != 0 && 1948 (instance->li_flags & LI_RECURSEMASK) == 0) 1949 panic("Lock (%s) %s not recursed @ %s:%d.", 1950 class->lc_name, lock->lo_name, file, line); 1951 if ((flags & LA_NOTRECURSED) != 0 && 1952 (instance->li_flags & LI_RECURSEMASK) != 0) 1953 panic("Lock (%s) %s recursed @ %s:%d.", 1954 class->lc_name, lock->lo_name, file, line); 1955 break; 1956 default: 1957 panic("Invalid lock assertion at %s:%d.", file, line); 1958 1959 } 1960 #endif /* INVARIANT_SUPPORT */ 1961 } 1962 1963 #ifdef DDB 1964 static void 1965 witness_list(struct thread *td) 1966 { 1967 1968 KASSERT(!witness_cold, ("%s: witness_cold", __func__)); 1969 KASSERT(kdb_active, ("%s: not in the debugger", __func__)); 1970 1971 if (witness_watch == 0) 1972 return; 1973 1974 witness_list_locks(&td->td_sleeplocks); 1975 1976 /* 1977 * We only handle spinlocks if td == curthread. This is somewhat broken 1978 * if td is currently executing on some other CPU and holds spin locks 1979 * as we won't display those locks. If we had a MI way of getting 1980 * the per-cpu data for a given cpu then we could use 1981 * td->td_oncpu to get the list of spinlocks for this thread 1982 * and "fix" this. 1983 * 1984 * That still wouldn't really fix this unless we locked the scheduler 1985 * lock or stopped the other CPU to make sure it wasn't changing the 1986 * list out from under us. It is probably best to just not try to 1987 * handle threads on other CPU's for now. 1988 */ 1989 if (td == curthread && PCPU_GET(spinlocks) != NULL) 1990 witness_list_locks(PCPU_PTR(spinlocks)); 1991 } 1992 1993 DB_SHOW_COMMAND(locks, db_witness_list) 1994 { 1995 struct thread *td; 1996 1997 if (have_addr) 1998 td = db_lookup_thread(addr, TRUE); 1999 else 2000 td = kdb_thread; 2001 witness_list(td); 2002 } 2003 2004 DB_SHOW_COMMAND(alllocks, db_witness_list_all) 2005 { 2006 struct thread *td; 2007 struct proc *p; 2008 2009 /* 2010 * It would be nice to list only threads and processes that actually 2011 * held sleep locks, but that information is currently not exported 2012 * by WITNESS. 2013 */ 2014 FOREACH_PROC_IN_SYSTEM(p) { 2015 if (!witness_proc_has_locks(p)) 2016 continue; 2017 FOREACH_THREAD_IN_PROC(p, td) { 2018 if (!witness_thread_has_locks(td)) 2019 continue; 2020 db_printf("Process %d (%s) thread %p (%d)\n", p->p_pid, 2021 p->p_comm, td, td->td_tid); 2022 witness_list(td); 2023 } 2024 } 2025 } 2026 2027 DB_SHOW_COMMAND(witness, db_witness_display) 2028 { 2029 2030 witness_display(db_printf); 2031 } 2032 #endif
Cache object: 018d1fb9363927a18322e6ab6c7ebfdf
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