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. --- 13 unchanged lines hidden (view full) --- 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 * $FreeBSD: head/sys/kern/kern_mutex.c 72200 2001-02-09 06:11:45Z bmilekic $ |
31 */ 32 33/* |
34 * Machine independent bits of mutex implementation and implementation of 35 * `witness' structure & related debugging routines. 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 --- 6 unchanged lines hidden (view full) --- 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#include "opt_ddb.h" 59#include "opt_witness.h" 60 |
61#include <sys/param.h> 62#include <sys/bus.h> 63#include <sys/kernel.h> 64#include <sys/malloc.h> 65#include <sys/proc.h> 66#include <sys/sysctl.h> 67#include <sys/systm.h> 68#include <sys/vmmeter.h> --- 7 unchanged lines hidden (view full) --- 76#include <ddb/ddb.h> 77 78#include <vm/vm.h> 79#include <vm/vm_extern.h> 80 81#include <sys/mutex.h> 82 83/* |
84 * The WITNESS-enabled mutex debug structure. |
85 */ |
86#ifdef WITNESS 87struct mtx_debug { 88 struct witness *mtxd_witness; 89 LIST_ENTRY(mtx) mtxd_held; 90 const char *mtxd_file; 91 int mtxd_line; 92}; 93 94#define mtx_held mtx_debug->mtxd_held 95#define mtx_file mtx_debug->mtxd_file 96#define mtx_line mtx_debug->mtxd_line 97#define mtx_witness mtx_debug->mtxd_witness 98#endif /* WITNESS */ 99 100/* |
101 * Internal utility macros. |
102 */ |
103#define mtx_unowned(m) ((m)->mtx_lock == MTX_UNOWNED) |
104 |
105#define mtx_owner(m) (mtx_unowned((m)) ? NULL \ 106 : (struct proc *)((m)->mtx_lock & MTX_FLAGMASK)) |
107 |
108#define RETIP(x) *(((uintptr_t *)(&x)) - 1) 109#define SET_PRIO(p, pri) (p)->p_priority = (pri) |
110 |
111/* |
112 * Early WITNESS-enabled declarations. |
113 */ |
114#ifdef WITNESS |
115 |
116/* |
117 * Internal WITNESS routines which must be prototyped early. 118 * 119 * XXX: When/if witness code is cleaned up, it would be wise to place all 120 * witness prototyping early in this file. 121 */ 122static void witness_init(struct mtx *, int flag); 123static void witness_destroy(struct mtx *); 124static void witness_display(void(*)(const char *fmt, ...)); |
125 |
126MALLOC_DEFINE(M_WITNESS, "witness", "witness mtx_debug structure"); |
127 |
128/* All mutexes in system (used for debug/panic) */ 129static struct mtx_debug all_mtx_debug = { NULL, {NULL, NULL}, NULL, 0 }; |
130 |
131/* |
132 * This global is set to 0 once it becomes safe to use the witness code. |
133 */ 134static int witness_cold = 1; |
135 |
136#else /* WITNESS */ 137 |
138/* XXX XXX XXX 139 * flag++ is sleazoid way of shuting up warning |
140 */ 141#define witness_init(m, flag) flag++ 142#define witness_destroy(m) 143#define witness_try_enter(m, t, f, l) 144#endif /* WITNESS */ 145 |
146/* 147 * All mutex locks in system are kept on the all_mtx list. 148 */ |
149static struct mtx all_mtx = { MTX_UNOWNED, 0, 0, 0, "All mutexes queue head", 150 TAILQ_HEAD_INITIALIZER(all_mtx.mtx_blocked), 151 { NULL, NULL }, &all_mtx, &all_mtx, 152#ifdef WITNESS 153 &all_mtx_debug 154#else 155 NULL 156#endif 157 }; 158 |
159/* 160 * Global variables for book keeping. 161 */ |
162static int mtx_cur_cnt; 163static int mtx_max_cnt; 164 |
165/* 166 * Prototypes for non-exported routines. 167 * 168 * NOTE: Prototypes for witness routines are placed at the bottom of the file. 169 */ |
170static void propagate_priority(struct proc *); |
171 |
172static void 173propagate_priority(struct proc *p) 174{ 175 int pri = p->p_priority; 176 struct mtx *m = p->p_blocked; 177 178 mtx_assert(&sched_lock, MA_OWNED); 179 for (;;) { --- 5 unchanged lines hidden (view full) --- 185 /* 186 * This really isn't quite right. Really 187 * ought to bump priority of process that 188 * next acquires the mutex. 189 */ 190 MPASS(m->mtx_lock == MTX_CONTESTED); 191 return; 192 } |
193 |
194 MPASS(p->p_magic == P_MAGIC); 195 KASSERT(p->p_stat != SSLEEP, ("sleeping process owns a mutex")); 196 if (p->p_priority <= pri) 197 return; 198 199 /* 200 * Bump this process' priority. 201 */ --- 21 unchanged lines hidden (view full) --- 223 return; 224 } 225#endif 226 /* 227 * If on run queue move to new run queue, and 228 * quit. 229 */ 230 if (p->p_stat == SRUN) { |
231 printf("XXX: moving proc %d(%s) to a new run queue\n", |
232 p->p_pid, p->p_comm); 233 MPASS(p->p_blocked == NULL); 234 remrunqueue(p); 235 setrunqueue(p); 236 return; 237 } 238 239 /* --- 7 unchanged lines hidden (view full) --- 247 /* 248 * Pick up the mutex that p is blocked on. 249 */ 250 m = p->p_blocked; 251 MPASS(m != NULL); 252 253 printf("XXX: process %d(%s) is blocked on %s\n", p->p_pid, 254 p->p_comm, m->mtx_description); |
255 |
256 /* 257 * Check if the proc needs to be moved up on 258 * the blocked chain 259 */ 260 if (p == TAILQ_FIRST(&m->mtx_blocked)) { 261 printf("XXX: process at head of run queue\n"); 262 continue; 263 } |
264 |
265 p1 = TAILQ_PREV(p, rq, p_procq); 266 if (p1->p_priority <= pri) { 267 printf( |
268 "XXX: previous process %d(%s) has higher priority\n", |
269 p->p_pid, p->p_comm); 270 continue; 271 } 272 273 /* 274 * Remove proc from blocked chain and determine where 275 * it should be moved up to. Since we know that p1 has 276 * a lower priority than p, we know that at least one 277 * process in the chain has a lower priority and that 278 * p1 will thus not be NULL after the loop. 279 */ 280 TAILQ_REMOVE(&m->mtx_blocked, p, p_procq); 281 TAILQ_FOREACH(p1, &m->mtx_blocked, p_procq) { 282 MPASS(p1->p_magic == P_MAGIC); 283 if (p1->p_priority > pri) 284 break; 285 } |
286 |
287 MPASS(p1 != NULL); 288 TAILQ_INSERT_BEFORE(p1, p, p_procq); 289 CTR4(KTR_LOCK, 290 "propagate_priority: p %p moved before %p on [%p] %s", 291 p, p1, m, m->mtx_description); 292 } 293} 294 295/* |
296 * The important part of mtx_trylock{,_flags}() 297 * Tries to acquire lock `m.' We do NOT handle recursion here; we assume that 298 * if we're called, it's because we know we don't already own this lock. |
299 */ |
300int 301_mtx_trylock(struct mtx *m, int opts, const char *file, int line) |
302{ |
303 int rval; |
304 |
305 KASSERT(CURPROC != NULL, ("curproc is NULL in _mtx_trylock")); |
306 |
307 /* 308 * _mtx_trylock does not accept MTX_NOSWITCH option. 309 */ 310 MPASS((opts & MTX_NOSWITCH) == 0); 311 312 rval = _obtain_lock(m, CURTHD); 313 314#ifdef WITNESS 315 if (rval && m->mtx_witness != NULL) { |
316 /* |
317 * We do not handle recursion in _mtx_trylock; see the 318 * note at the top of the routine. |
319 */ |
320 MPASS(!mtx_recursed(m)); 321 witness_try_enter(m, (opts | m->mtx_flags), file, line); |
322 } |
323#endif /* WITNESS */ |
324 |
325 if ((opts & MTX_QUIET) == 0) 326 CTR5(KTR_LOCK, "TRY_ENTER %s [%p] result=%d at %s:%d", 327 m->mtx_description, m, rval, file, line); 328 329 return rval; |
330} 331 332/* |
333 * _mtx_lock_sleep: the tougher part of acquiring an MTX_DEF lock. |
334 * |
335 * We call this if the lock is either contested (i.e. we need to go to 336 * sleep waiting for it), or if we need to recurse on it. |
337 */ |
338void 339_mtx_lock_sleep(struct mtx *m, int opts, const char *file, int line) |
340{ |
341 struct proc *p = CURPROC; |
342 |
343 if ((m->mtx_lock & MTX_FLAGMASK) == (uintptr_t)p) { 344 m->mtx_recurse++; 345 atomic_set_ptr(&m->mtx_lock, MTX_RECURSED); 346 if ((opts & MTX_QUIET) == 0) 347 CTR1(KTR_LOCK, "_mtx_lock_sleep: %p recurse", m); 348 return; |
349 } |
350 |
351 if ((opts & MTX_QUIET) == 0) 352 CTR3(KTR_LOCK, "mtx_lock: %p contested (lock=%p) [%p]", m, 353 (void *)m->mtx_lock, (void *)RETIP(m)); |
354 |
355 /* 356 * Save our priority. Even though p_nativepri is protected by 357 * sched_lock, we don't obtain it here as it can be expensive. 358 * Since this is the only place p_nativepri is set, and since two 359 * CPUs will not be executing the same process concurrently, we know 360 * that no other CPU is going to be messing with this. Also, 361 * p_nativepri is only read when we are blocked on a mutex, so that 362 * can't be happening right now either. 363 */ 364 p->p_nativepri = p->p_priority; |
365 |
366 while (!_obtain_lock(m, p)) { 367 uintptr_t v; 368 struct proc *p1; |
369 |
370 mtx_lock_spin(&sched_lock); 371 /* 372 * Check if the lock has been released while spinning for 373 * the sched_lock. 374 */ 375 if ((v = m->mtx_lock) == MTX_UNOWNED) { 376 mtx_unlock_spin(&sched_lock); 377 continue; |
378 } |
379 |
380 /* 381 * The mutex was marked contested on release. This means that 382 * there are processes blocked on it. 383 */ 384 if (v == MTX_CONTESTED) { 385 p1 = TAILQ_FIRST(&m->mtx_blocked); 386 KASSERT(p1 != NULL, 387 ("contested mutex has no contesters")); 388 m->mtx_lock = (uintptr_t)p | MTX_CONTESTED; |
389 |
390 if (p1->p_priority < p->p_priority) 391 SET_PRIO(p, p1->p_priority); 392 mtx_unlock_spin(&sched_lock); |
393 return; 394 } |
395 396 /* |
397 * If the mutex isn't already contested and a failure occurs 398 * setting the contested bit, the mutex was either released 399 * or the state of the MTX_RECURSED bit changed. |
400 */ |
401 if ((v & MTX_CONTESTED) == 0 && 402 !atomic_cmpset_ptr(&m->mtx_lock, (void *)v, 403 (void *)(v | MTX_CONTESTED))) { 404 mtx_unlock_spin(&sched_lock); 405 continue; 406 } |
407 |
408 /* 409 * We deffinately must sleep for this lock. 410 */ 411 mtx_assert(m, MA_NOTOWNED); |
412 |
413#ifdef notyet |
414 /* 415 * If we're borrowing an interrupted thread's VM context, we 416 * must clean up before going to sleep. 417 */ 418 if (p->p_flag & (P_ITHD | P_SITHD)) { 419 ithd_t *it = (ithd_t *)p; |
420 |
421 if (it->it_interrupted) { 422 if ((opts & MTX_QUIET) == 0) 423 CTR2(KTR_LOCK, 424 "mtx_lock: 0x%x interrupted 0x%x", 425 it, it->it_interrupted); 426 intr_thd_fixup(it); |
427 } |
428 } |
429#endif 430 |
431 /* 432 * Put us on the list of threads blocked on this mutex. 433 */ 434 if (TAILQ_EMPTY(&m->mtx_blocked)) { 435 p1 = (struct proc *)(m->mtx_lock & MTX_FLAGMASK); 436 LIST_INSERT_HEAD(&p1->p_contested, m, mtx_contested); 437 TAILQ_INSERT_TAIL(&m->mtx_blocked, p, p_procq); 438 } else { 439 TAILQ_FOREACH(p1, &m->mtx_blocked, p_procq) 440 if (p1->p_priority > p->p_priority) 441 break; 442 if (p1) 443 TAILQ_INSERT_BEFORE(p1, p, p_procq); 444 else |
445 TAILQ_INSERT_TAIL(&m->mtx_blocked, p, p_procq); |
446 } |
447 |
448 /* 449 * Save who we're blocked on. 450 */ 451 p->p_blocked = m; 452 p->p_mtxname = m->mtx_description; 453 p->p_stat = SMTX; |
454#if 0 |
455 propagate_priority(p); |
456#endif |
457 |
458 if ((opts & MTX_QUIET) == 0) 459 CTR3(KTR_LOCK, 460 "_mtx_lock_sleep: p %p blocked on [%p] %s", p, m, 461 m->mtx_description); 462 463 mi_switch(); 464 465 if ((opts & MTX_QUIET) == 0) 466 CTR3(KTR_LOCK, 467 "_mtx_lock_sleep: p %p free from blocked on [%p] %s", 468 p, m, m->mtx_description); 469 470 mtx_unlock_spin(&sched_lock); 471 } 472 473 return; 474} 475 476/* 477 * _mtx_lock_spin: the tougher part of acquiring an MTX_SPIN lock. 478 * 479 * This is only called if we need to actually spin for the lock. Recursion 480 * is handled inline. 481 */ 482void 483_mtx_lock_spin(struct mtx *m, int opts, u_int mtx_intr, const char *file, 484 int line) 485{ 486 int i = 0; 487 488 if ((opts & MTX_QUIET) == 0) 489 CTR1(KTR_LOCK, "mtx_lock_spin: %p spinning", m); 490 491 for (;;) { 492 if (_obtain_lock(m, CURPROC)) 493 break; 494 495 while (m->mtx_lock != MTX_UNOWNED) { 496 if (i++ < 1000000) 497 continue; 498 if (i++ < 6000000) 499 DELAY(1); |
500#ifdef DDB |
501 else if (!db_active) |
502#else |
503 else |
504#endif |
505 panic("spin lock %s held by %p for > 5 seconds", 506 m->mtx_description, (void *)m->mtx_lock); |
507 } |
508 } |
509 510 m->mtx_saveintr = mtx_intr; 511 if ((opts & MTX_QUIET) == 0) 512 CTR1(KTR_LOCK, "_mtx_lock_spin: %p spin done", m); 513 514 return; |
515} 516 |
517/* 518 * _mtx_unlock_sleep: the tougher part of releasing an MTX_DEF lock. 519 * 520 * We are only called here if the lock is recursed or contested (i.e. we 521 * need to wake up a blocked thread). 522 */ |
523void |
524_mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line) |
525{ 526 struct proc *p, *p1; 527 struct mtx *m1; 528 int pri; 529 530 p = CURPROC; |
531 MPASS4(mtx_owned(m), "mtx_owned(mpp)", file, line); 532 533 if ((opts & MTX_QUIET) == 0) 534 CTR5(KTR_LOCK, "REL %s [%p] r=%d at %s:%d", m->mtx_description, 535 m, m->mtx_recurse, file, line); 536 537 if (mtx_recursed(m)) { 538 if (--(m->mtx_recurse) == 0) 539 atomic_clear_ptr(&m->mtx_lock, MTX_RECURSED); 540 if ((opts & MTX_QUIET) == 0) 541 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p unrecurse", m); 542 return; 543 } 544 545 mtx_lock_spin(&sched_lock); 546 if ((opts & MTX_QUIET) == 0) 547 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m); 548 549 p1 = TAILQ_FIRST(&m->mtx_blocked); 550 MPASS(p->p_magic == P_MAGIC); 551 MPASS(p1->p_magic == P_MAGIC); 552 553 TAILQ_REMOVE(&m->mtx_blocked, p1, p_procq); 554 555 if (TAILQ_EMPTY(&m->mtx_blocked)) { 556 LIST_REMOVE(m, mtx_contested); 557 _release_lock_quick(m); 558 if ((opts & MTX_QUIET) == 0) 559 CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p not held", m); 560 } else 561 atomic_store_rel_ptr(&m->mtx_lock, (void *)MTX_CONTESTED); 562 563 pri = MAXPRI; 564 LIST_FOREACH(m1, &p->p_contested, mtx_contested) { 565 int cp = TAILQ_FIRST(&m1->mtx_blocked)->p_priority; 566 if (cp < pri) 567 pri = cp; 568 } 569 570 if (pri > p->p_nativepri) 571 pri = p->p_nativepri; 572 SET_PRIO(p, pri); 573 574 if ((opts & MTX_QUIET) == 0) 575 CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p contested setrunqueue %p", 576 m, p1); 577 578 p1->p_blocked = NULL; 579 p1->p_mtxname = NULL; 580 p1->p_stat = SRUN; 581 setrunqueue(p1); 582 583 if ((opts & MTX_NOSWITCH) == 0 && p1->p_priority < pri) { |
584#ifdef notyet |
585 if (p->p_flag & (P_ITHD | P_SITHD)) { 586 ithd_t *it = (ithd_t *)p; |
587 |
588 if (it->it_interrupted) { 589 if ((opts & MTX_QUIET) == 0) 590 CTR2(KTR_LOCK, 591 "_mtx_unlock_sleep: 0x%x interrupted 0x%x", 592 it, it->it_interrupted); 593 intr_thd_fixup(it); |
594 } |
595 } |
596#endif 597 setrunqueue(p); 598 if ((opts & MTX_QUIET) == 0) 599 CTR2(KTR_LOCK, 600 "_mtx_unlock_sleep: %p switching out lock=%p", m, 601 (void *)m->mtx_lock); 602 603 mi_switch(); 604 if ((opts & MTX_QUIET) == 0) 605 CTR2(KTR_LOCK, "_mtx_unlock_sleep: %p resuming lock=%p", 606 m, (void *)m->mtx_lock); |
607 } |
608 609 mtx_unlock_spin(&sched_lock); 610 611 return; |
612} 613 |
614/* 615 * All the unlocking of MTX_SPIN locks is done inline. 616 * See the _rel_spin_lock() macro for the details. 617 */ 618 619/* 620 * The INVARIANTS-enabled mtx_assert() 621 */ |
622#ifdef INVARIANTS 623void 624_mtx_assert(struct mtx *m, int what, const char *file, int line) 625{ 626 switch ((what)) { 627 case MA_OWNED: 628 case MA_OWNED | MA_RECURSED: 629 case MA_OWNED | MA_NOTRECURSED: --- 15 unchanged lines hidden (view full) --- 645 (m)->mtx_description, file, line); 646 break; 647 default: 648 panic("unknown mtx_assert at %s:%d", file, line); 649 } 650} 651#endif 652 |
653/* 654 * The MUTEX_DEBUG-enabled mtx_validate() 655 */ |
656#define MV_DESTROY 0 /* validate before destory */ 657#define MV_INIT 1 /* validate before init */ 658 659#ifdef MUTEX_DEBUG 660 661int mtx_validate __P((struct mtx *, int)); 662 663int --- 5 unchanged lines hidden (view full) --- 669 670#ifdef WITNESS 671 if (witness_cold) 672 return 0; 673#endif 674 if (m == &all_mtx || cold) 675 return 0; 676 |
677 mtx_lock(&all_mtx); |
678/* 679 * XXX - When kernacc() is fixed on the alpha to handle K0_SEG memory properly 680 * we can re-enable the kernacc() checks. 681 */ 682#ifndef __alpha__ 683 MPASS(kernacc((caddr_t)all_mtx.mtx_next, sizeof(uintptr_t), 684 VM_PROT_READ) == 1); 685#endif --- 27 unchanged lines hidden (view full) --- 713 * Not good. This mutex already exists. 714 */ 715 printf("re-initing existing mutex %s\n", 716 m->mtx_description); 717 MPASS(m->mtx_lock == MTX_UNOWNED); 718 retval = 1; 719 } 720 } |
721 mtx_unlock(&all_mtx); |
722 return (retval); 723} 724#endif 725 |
726/* 727 * Mutex initialization routine; initialize lock `m' of type contained in 728 * `opts' with options contained in `opts' and description `description.' 729 * Place on "all_mtx" queue. 730 */ |
731void |
732mtx_init(struct mtx *m, const char *description, int opts) |
733{ |
734 735 if ((opts & MTX_QUIET) == 0) 736 CTR2(KTR_LOCK, "mtx_init %p (%s)", m, description); 737 |
738#ifdef MUTEX_DEBUG |
739 /* Diagnostic and error correction */ 740 if (mtx_validate(m, MV_INIT)) |
741 return; 742#endif 743 744 bzero((void *)m, sizeof *m); 745 TAILQ_INIT(&m->mtx_blocked); |
746 |
747#ifdef WITNESS 748 if (!witness_cold) { |
749 m->mtx_debug = malloc(sizeof(struct mtx_debug), |
750 M_WITNESS, M_NOWAIT | M_ZERO); |
751 MPASS(m->mtx_debug != NULL); 752 } 753#endif |
754 |
755 m->mtx_description = description; 756 m->mtx_flags = opts; |
757 m->mtx_lock = MTX_UNOWNED; |
758 |
759 /* Put on all mutex queue */ |
760 mtx_lock(&all_mtx); |
761 m->mtx_next = &all_mtx; 762 m->mtx_prev = all_mtx.mtx_prev; 763 m->mtx_prev->mtx_next = m; 764 all_mtx.mtx_prev = m; 765 if (++mtx_cur_cnt > mtx_max_cnt) 766 mtx_max_cnt = mtx_cur_cnt; |
767 mtx_unlock(&all_mtx); 768 |
769#ifdef WITNESS 770 if (!witness_cold) |
771 witness_init(m, opts); |
772#endif 773} 774 |
775/* 776 * Remove lock `m' from all_mtx queue. 777 */ |
778void 779mtx_destroy(struct mtx *m) 780{ 781 782#ifdef WITNESS 783 KASSERT(!witness_cold, ("%s: Cannot destroy while still cold\n", 784 __FUNCTION__)); 785#endif |
786 |
787 CTR2(KTR_LOCK, "mtx_destroy %p (%s)", m, m->mtx_description); |
788 |
789#ifdef MUTEX_DEBUG 790 if (m->mtx_next == NULL) 791 panic("mtx_destroy: %p (%s) already destroyed", 792 m, m->mtx_description); 793 794 if (!mtx_owned(m)) { 795 MPASS(m->mtx_lock == MTX_UNOWNED); 796 } else { 797 MPASS((m->mtx_lock & (MTX_RECURSED|MTX_CONTESTED)) == 0); 798 } |
799 800 /* diagnostic */ 801 mtx_validate(m, MV_DESTROY); |
802#endif 803 804#ifdef WITNESS 805 if (m->mtx_witness) 806 witness_destroy(m); 807#endif /* WITNESS */ 808 809 /* Remove from the all mutex queue */ |
810 mtx_lock(&all_mtx); |
811 m->mtx_next->mtx_prev = m->mtx_prev; 812 m->mtx_prev->mtx_next = m->mtx_next; |
813 |
814#ifdef MUTEX_DEBUG 815 m->mtx_next = m->mtx_prev = NULL; 816#endif |
817 |
818#ifdef WITNESS |
819 free(m->mtx_debug, M_WITNESS); |
820 m->mtx_debug = NULL; 821#endif |
822 |
823 mtx_cur_cnt--; |
824 mtx_unlock(&all_mtx); |
825} 826 |
827 |
828/* |
829 * The WITNESS-enabled diagnostic code. |
830 */ |
831#ifdef WITNESS 832static void 833witness_fixup(void *dummy __unused) 834{ 835 struct mtx *mp; 836 837 /* 838 * We have to release Giant before initializing its witness 839 * structure so that WITNESS doesn't get confused. 840 */ |
841 mtx_unlock(&Giant); |
842 mtx_assert(&Giant, MA_NOTOWNED); |
843 |
844 mtx_lock(&all_mtx); 845 |
846 /* Iterate through all mutexes and finish up mutex initialization. */ 847 for (mp = all_mtx.mtx_next; mp != &all_mtx; mp = mp->mtx_next) { 848 |
849 mp->mtx_debug = malloc(sizeof(struct mtx_debug), |
850 M_WITNESS, M_NOWAIT | M_ZERO); |
851 MPASS(mp->mtx_debug != NULL); 852 853 witness_init(mp, mp->mtx_flags); 854 } |
855 mtx_unlock(&all_mtx); |
856 857 /* Mark the witness code as being ready for use. */ 858 atomic_store_rel_int(&witness_cold, 0); 859 |
860 mtx_lock(&Giant); |
861} 862SYSINIT(wtnsfxup, SI_SUB_MUTEX, SI_ORDER_FIRST, witness_fixup, NULL) 863 864#define WITNESS_COUNT 200 865#define WITNESS_NCHILDREN 2 866 867int witness_watch = 1; 868 --- 37 unchanged lines hidden (view full) --- 906#ifdef WITNESS_SKIPSPIN 907TUNABLE_INT_DECL("debug.witness_skipspin", 1, witness_skipspin); 908#else 909TUNABLE_INT_DECL("debug.witness_skipspin", 0, witness_skipspin); 910#endif 911SYSCTL_INT(_debug, OID_AUTO, witness_skipspin, CTLFLAG_RD, &witness_skipspin, 0, 912 ""); 913 |
914/* 915 * Witness-enabled globals 916 */ |
917static struct mtx w_mtx; 918static struct witness *w_free; 919static struct witness *w_all; 920static int w_inited; 921static int witness_dead; /* fatal error, probably no memory */ 922 923static struct witness w_data[WITNESS_COUNT]; 924 |
925/* 926 * Internal witness routine prototypes 927 */ 928static struct witness *enroll(const char *description, int flag); 929static int itismychild(struct witness *parent, struct witness *child); 930static void removechild(struct witness *parent, struct witness *child); 931static int isitmychild(struct witness *parent, struct witness *child); 932static int isitmydescendant(struct witness *parent, struct witness *child); 933static int dup_ok(struct witness *); 934static int blessed(struct witness *, struct witness *); 935static void 936 witness_displaydescendants(void(*)(const char *fmt, ...), struct witness *); 937static void witness_leveldescendents(struct witness *parent, int level); 938static void witness_levelall(void); 939static struct witness * witness_get(void); 940static void witness_free(struct witness *m); |
941 |
942static char *ignore_list[] = { 943 "witness lock", 944 NULL 945}; 946 947static char *spin_order_list[] = { 948 "sio", 949 "sched lock", --- 29 unchanged lines hidden (view full) --- 979}; 980 981/* 982 * Pairs of locks which have been blessed 983 * Don't complain about order problems with blessed locks 984 */ 985static struct witness_blessed blessed_list[] = { 986}; |
987static int blessed_count = 988 sizeof(blessed_list) / sizeof(struct witness_blessed); |
989 990static void 991witness_init(struct mtx *m, int flag) 992{ 993 m->mtx_witness = enroll(m->mtx_description, flag); 994} 995 996static void --- 65 unchanged lines hidden (view full) --- 1062 " %s:%d", m->mtx_description, file, line); 1063 if (mtx_recursed(m)) { 1064 if ((m->mtx_flags & MTX_RECURSE) == 0) 1065 panic("mutex_enter: recursion on non-recursive" 1066 " mutex %s @ %s:%d", m->mtx_description, 1067 file, line); 1068 return; 1069 } |
1070 mtx_lock_spin_flags(&w_mtx, MTX_QUIET); |
1071 i = PCPU_GET(witness_spin_check); 1072 if (i != 0 && w->w_level < i) { |
1073 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1074 panic("mutex_enter(%s:%x, MTX_SPIN) out of order @" 1075 " %s:%d already holding %s:%x", 1076 m->mtx_description, w->w_level, file, line, 1077 spin_order_list[ffs(i)-1], i); 1078 } 1079 PCPU_SET(witness_spin_check, i | w->w_level); |
1080 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1081 w->w_file = file; 1082 w->w_line = line; 1083 m->mtx_line = line; 1084 m->mtx_file = file; 1085 return; 1086 } 1087 if ((m->mtx_flags & MTX_SPIN) != 0) 1088 panic("mutex_enter: MTX_DEF on MTX_SPIN mutex %s @ %s:%d", --- 7 unchanged lines hidden (view full) --- 1096 return; 1097 } 1098 if (witness_dead) 1099 goto out; 1100 if (cold) 1101 goto out; 1102 1103 if (!mtx_legal2block()) |
1104 panic("blockable mtx_lock() of %s when not legal @ %s:%d", |
1105 m->mtx_description, file, line); 1106 /* 1107 * Is this the first mutex acquired 1108 */ 1109 if ((m1 = LIST_FIRST(&p->p_heldmtx)) == NULL) 1110 goto out; 1111 1112 if ((w1 = m1->mtx_witness) == w) { --- 5 unchanged lines hidden (view full) --- 1118 printf(" 1st @ %s:%d\n", w->w_file, w->w_line); 1119 printf(" 2nd @ %s:%d\n", file, line); 1120#ifdef DDB 1121 go_into_ddb = 1; 1122#endif /* DDB */ 1123 goto out; 1124 } 1125 MPASS(!mtx_owned(&w_mtx)); |
1126 mtx_lock_spin_flags(&w_mtx, MTX_QUIET); |
1127 /* 1128 * If we have a known higher number just say ok 1129 */ 1130 if (witness_watch > 1 && w->w_level > w1->w_level) { |
1131 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1132 goto out; 1133 } 1134 if (isitmydescendant(m1->mtx_witness, w)) { |
1135 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1136 goto out; 1137 } 1138 for (i = 0; m1 != NULL; m1 = LIST_NEXT(m1, mtx_held), i++) { 1139 1140 MPASS(i < 200); 1141 w1 = m1->mtx_witness; 1142 if (isitmydescendant(w, w1)) { |
1143 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1144 if (blessed(w, w1)) 1145 goto out; 1146 if (m1 == &Giant) { 1147 if (w1->w_Giant_squawked) 1148 goto out; 1149 else 1150 w1->w_Giant_squawked = 1; 1151 } else { --- 12 unchanged lines hidden (view full) --- 1164#ifdef DDB 1165 go_into_ddb = 1; 1166#endif /* DDB */ 1167 goto out; 1168 } 1169 } 1170 m1 = LIST_FIRST(&p->p_heldmtx); 1171 if (!itismychild(m1->mtx_witness, w)) |
1172 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1173 1174out: 1175#ifdef DDB 1176 if (witness_ddb && go_into_ddb) 1177 Debugger("witness_enter"); 1178#endif /* DDB */ 1179 w->w_file = file; 1180 w->w_line = line; --- 26 unchanged lines hidden (view full) --- 1207 m->mtx_description, file, line); 1208 if (mtx_recursed(m)) { 1209 if ((m->mtx_flags & MTX_RECURSE) == 0) 1210 panic("mutex_try_enter: recursion on" 1211 " non-recursive mutex %s @ %s:%d", 1212 m->mtx_description, file, line); 1213 return; 1214 } |
1215 mtx_lock_spin_flags(&w_mtx, MTX_QUIET); |
1216 PCPU_SET(witness_spin_check, 1217 PCPU_GET(witness_spin_check) | w->w_level); |
1218 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1219 w->w_file = file; 1220 w->w_line = line; 1221 m->mtx_line = line; 1222 m->mtx_file = file; 1223 return; 1224 } 1225 1226 if ((m->mtx_flags & MTX_SPIN) != 0) --- 31 unchanged lines hidden (view full) --- 1258 " %s:%d", m->mtx_description, file, line); 1259 if (mtx_recursed(m)) { 1260 if ((m->mtx_flags & MTX_RECURSE) == 0) 1261 panic("mutex_exit: recursion on non-recursive" 1262 " mutex %s @ %s:%d", m->mtx_description, 1263 file, line); 1264 return; 1265 } |
1266 mtx_lock_spin_flags(&w_mtx, MTX_QUIET); |
1267 PCPU_SET(witness_spin_check, 1268 PCPU_GET(witness_spin_check) & ~w->w_level); |
1269 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1270 return; 1271 } 1272 if ((m->mtx_flags & MTX_SPIN) != 0) 1273 panic("mutex_exit: MTX_DEF on MTX_SPIN mutex %s @ %s:%d", 1274 m->mtx_description, file, line); 1275 1276 if (mtx_recursed(m)) { 1277 if ((m->mtx_flags & MTX_RECURSE) == 0) 1278 panic("mutex_exit: recursion on non-recursive" 1279 " mutex %s @ %s:%d", m->mtx_description, 1280 file, line); 1281 return; 1282 } 1283 1284 if ((flags & MTX_NOSWITCH) == 0 && !mtx_legal2block() && !cold) |
1285 panic("switchable mtx_unlock() of %s when not legal @ %s:%d", |
1286 m->mtx_description, file, line); 1287 LIST_REMOVE(m, mtx_held); 1288 m->mtx_held.le_prev = NULL; 1289} 1290 1291int 1292witness_sleep(int check_only, struct mtx *mtx, const char *file, int line) 1293{ --- 54 unchanged lines hidden (view full) --- 1348 w1->w_file = "order list"; 1349 itismychild(w, w1); 1350 w = w1; 1351 } 1352 } 1353 } 1354 if ((flag & MTX_SPIN) && witness_skipspin) 1355 return (NULL); |
1356 mtx_lock_spin_flags(&w_mtx, MTX_QUIET); |
1357 for (w = w_all; w; w = w->w_next) { 1358 if (strcmp(description, w->w_description) == 0) { |
1359 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1360 return (w); 1361 } 1362 } 1363 if ((w = witness_get()) == NULL) 1364 return (NULL); 1365 w->w_next = w_all; 1366 w_all = w; 1367 w->w_description = description; |
1368 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1369 if (flag & MTX_SPIN) { 1370 w->w_spin = 1; 1371 1372 i = 1; 1373 for (order = spin_order_list; *order != NULL; order++) { 1374 if (strcmp(description, *order) == 0) 1375 break; 1376 i <<= 1; --- 205 unchanged lines hidden (view full) --- 1582 1583static struct witness * 1584witness_get() 1585{ 1586 struct witness *w; 1587 1588 if ((w = w_free) == NULL) { 1589 witness_dead = 1; |
1590 mtx_unlock_spin_flags(&w_mtx, MTX_QUIET); |
1591 printf("witness exhausted\n"); 1592 return (NULL); 1593 } 1594 w_free = w->w_next; 1595 bzero(w, sizeof(*w)); 1596 return (w); 1597} 1598 --- 61 unchanged lines hidden --- |