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