subr_lockdebug.c revision 1.5.2.1
1 /* $NetBSD: subr_lockdebug.c,v 1.5.2.1 2007/06/08 14:17:24 ad Exp $ */ 2 3 /*- 4 * Copyright (c) 2006, 2007 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Andrew Doran. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39 /* 40 * Basic lock debugging code shared among lock primatives. 41 */ 42 43 #include "opt_multiprocessor.h" 44 #include "opt_ddb.h" 45 46 #include <sys/cdefs.h> 47 __KERNEL_RCSID(0, "$NetBSD: subr_lockdebug.c,v 1.5.2.1 2007/06/08 14:17:24 ad Exp $"); 48 49 #include <sys/param.h> 50 #include <sys/proc.h> 51 #include <sys/systm.h> 52 #include <sys/kmem.h> 53 #include <sys/lock.h> 54 #include <sys/lockdebug.h> 55 #include <sys/sleepq.h> 56 57 #include <machine/cpu.h> 58 59 #ifdef LOCKDEBUG 60 61 #define LD_BATCH_SHIFT 9 62 #define LD_BATCH (1 << LD_BATCH_SHIFT) 63 #define LD_BATCH_MASK (LD_BATCH - 1) 64 #define LD_MAX_LOCKS 1048576 65 #define LD_SLOP 16 66 67 #define LD_LOCKED 0x01 68 #define LD_SLEEPER 0x02 69 70 #define LD_NOID (LD_MAX_LOCKS + 1) 71 72 typedef union lockdebuglk { 73 struct { 74 __cpu_simple_lock_t lku_lock; 75 int lku_oldspl; 76 } ul; 77 uint8_t lk_pad[64]; 78 } volatile __aligned(64) lockdebuglk_t; 79 80 #define lk_lock ul.lku_lock 81 #define lk_oldspl ul.lku_oldspl 82 83 typedef struct lockdebug { 84 _TAILQ_ENTRY(struct lockdebug, volatile) ld_chain; 85 _TAILQ_ENTRY(struct lockdebug, volatile) ld_achain; 86 volatile void *ld_lock; 87 lockops_t *ld_lockops; 88 struct lwp *ld_lwp; 89 uintptr_t ld_locked; 90 uintptr_t ld_unlocked; 91 u_int ld_id; 92 uint16_t ld_shares; 93 uint16_t ld_cpu; 94 uint8_t ld_flags; 95 uint8_t ld_shwant; /* advisory */ 96 uint8_t ld_exwant; /* advisory */ 97 uint8_t ld_unused; 98 } volatile lockdebug_t; 99 100 typedef _TAILQ_HEAD(lockdebuglist, struct lockdebug, volatile) lockdebuglist_t; 101 102 lockdebuglk_t ld_sleeper_lk; 103 lockdebuglk_t ld_spinner_lk; 104 lockdebuglk_t ld_free_lk; 105 106 lockdebuglist_t ld_sleepers; 107 lockdebuglist_t ld_spinners; 108 lockdebuglist_t ld_free; 109 lockdebuglist_t ld_all; 110 int ld_nfree; 111 int ld_freeptr; 112 int ld_recurse; 113 bool ld_nomore; 114 lockdebug_t *ld_table[LD_MAX_LOCKS / LD_BATCH]; 115 116 lockdebug_t ld_prime[LD_BATCH]; 117 118 static void lockdebug_abort1(lockdebug_t *, lockdebuglk_t *lk, 119 const char *, const char *); 120 static void lockdebug_more(void); 121 static void lockdebug_init(void); 122 123 static inline void 124 lockdebug_lock(lockdebuglk_t *lk) 125 { 126 int s; 127 128 s = spllock(); 129 __cpu_simple_lock(&lk->lk_lock); 130 lk->lk_oldspl = s; 131 } 132 133 static inline void 134 lockdebug_unlock(lockdebuglk_t *lk) 135 { 136 int s; 137 138 s = lk->lk_oldspl; 139 __cpu_simple_unlock(&(lk->lk_lock)); 140 splx(s); 141 } 142 143 /* 144 * lockdebug_lookup: 145 * 146 * Find a lockdebug structure by ID and return it locked. 147 */ 148 static inline lockdebug_t * 149 lockdebug_lookup(u_int id, lockdebuglk_t **lk) 150 { 151 lockdebug_t *base, *ld; 152 153 if (id == LD_NOID) 154 return NULL; 155 156 if (id == 0 || id >= LD_MAX_LOCKS) 157 panic("lockdebug_lookup: uninitialized lock (1, id=%d)", id); 158 159 base = ld_table[id >> LD_BATCH_SHIFT]; 160 ld = base + (id & LD_BATCH_MASK); 161 162 if (base == NULL || ld->ld_lock == NULL || ld->ld_id != id) 163 panic("lockdebug_lookup: uninitialized lock (2, id=%d)", id); 164 165 if ((ld->ld_flags & LD_SLEEPER) != 0) 166 *lk = &ld_sleeper_lk; 167 else 168 *lk = &ld_spinner_lk; 169 170 lockdebug_lock(*lk); 171 return ld; 172 } 173 174 /* 175 * lockdebug_init: 176 * 177 * Initialize the lockdebug system. Allocate an initial pool of 178 * lockdebug structures before the VM system is up and running. 179 */ 180 static void 181 lockdebug_init(void) 182 { 183 lockdebug_t *ld; 184 int i; 185 186 __cpu_simple_lock_init(&ld_sleeper_lk.lk_lock); 187 __cpu_simple_lock_init(&ld_spinner_lk.lk_lock); 188 __cpu_simple_lock_init(&ld_free_lk.lk_lock); 189 190 TAILQ_INIT(&ld_free); 191 TAILQ_INIT(&ld_all); 192 TAILQ_INIT(&ld_sleepers); 193 TAILQ_INIT(&ld_spinners); 194 195 ld = ld_prime; 196 ld_table[0] = ld; 197 for (i = 1, ld++; i < LD_BATCH; i++, ld++) { 198 ld->ld_id = i; 199 TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain); 200 TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain); 201 } 202 ld_freeptr = 1; 203 ld_nfree = LD_BATCH - 1; 204 } 205 206 /* 207 * lockdebug_alloc: 208 * 209 * A lock is being initialized, so allocate an associated debug 210 * structure. 211 */ 212 u_int 213 lockdebug_alloc(volatile void *lock, lockops_t *lo) 214 { 215 struct cpu_info *ci; 216 lockdebug_t *ld; 217 218 if (lo == NULL || panicstr != NULL) 219 return LD_NOID; 220 if (ld_freeptr == 0) 221 lockdebug_init(); 222 223 ci = curcpu(); 224 225 /* 226 * Pinch a new debug structure. We may recurse because we call 227 * kmem_alloc(), which may need to initialize new locks somewhere 228 * down the path. If not recursing, we try to maintain at least 229 * LD_SLOP structures free, which should hopefully be enough to 230 * satisfy kmem_alloc(). If we can't provide a structure, not to 231 * worry: we'll just mark the lock as not having an ID. 232 */ 233 lockdebug_lock(&ld_free_lk); 234 ci->ci_lkdebug_recurse++; 235 236 if (TAILQ_EMPTY(&ld_free)) { 237 if (ci->ci_lkdebug_recurse > 1 || ld_nomore) { 238 ci->ci_lkdebug_recurse--; 239 lockdebug_unlock(&ld_free_lk); 240 return LD_NOID; 241 } 242 lockdebug_more(); 243 } else if (ci->ci_lkdebug_recurse == 1 && ld_nfree < LD_SLOP) 244 lockdebug_more(); 245 246 if ((ld = TAILQ_FIRST(&ld_free)) == NULL) { 247 lockdebug_unlock(&ld_free_lk); 248 return LD_NOID; 249 } 250 251 TAILQ_REMOVE(&ld_free, ld, ld_chain); 252 ld_nfree--; 253 254 ci->ci_lkdebug_recurse--; 255 lockdebug_unlock(&ld_free_lk); 256 257 if (ld->ld_lock != NULL) 258 panic("lockdebug_alloc: corrupt table"); 259 260 if (lo->lo_sleeplock) 261 lockdebug_lock(&ld_sleeper_lk); 262 else 263 lockdebug_lock(&ld_spinner_lk); 264 265 /* Initialise the structure. */ 266 ld->ld_lock = lock; 267 ld->ld_lockops = lo; 268 ld->ld_locked = 0; 269 ld->ld_unlocked = 0; 270 ld->ld_lwp = NULL; 271 272 if (lo->lo_sleeplock) { 273 ld->ld_flags = LD_SLEEPER; 274 lockdebug_unlock(&ld_sleeper_lk); 275 } else { 276 ld->ld_flags = 0; 277 lockdebug_unlock(&ld_spinner_lk); 278 } 279 280 return ld->ld_id; 281 } 282 283 /* 284 * lockdebug_free: 285 * 286 * A lock is being destroyed, so release debugging resources. 287 */ 288 void 289 lockdebug_free(volatile void *lock, u_int id) 290 { 291 lockdebug_t *ld; 292 lockdebuglk_t *lk; 293 294 if (panicstr != NULL) 295 return; 296 297 if ((ld = lockdebug_lookup(id, &lk)) == NULL) 298 return; 299 300 if (ld->ld_lock != lock) { 301 panic("lockdebug_free: destroying uninitialized lock %p" 302 "(ld_id=%d ld_lock=%p)", lock, id, ld->ld_lock); 303 lockdebug_abort1(ld, lk, __func__, "lock record follows"); 304 } 305 if ((ld->ld_flags & LD_LOCKED) != 0 || ld->ld_shares != 0) 306 lockdebug_abort1(ld, lk, __func__, "is locked"); 307 308 ld->ld_lock = NULL; 309 310 lockdebug_unlock(lk); 311 312 lockdebug_lock(&ld_free_lk); 313 TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain); 314 ld_nfree++; 315 lockdebug_unlock(&ld_free_lk); 316 } 317 318 /* 319 * lockdebug_more: 320 * 321 * Allocate a batch of debug structures and add to the free list. 322 * Must be called with ld_free_lk held. 323 */ 324 static void 325 lockdebug_more(void) 326 { 327 lockdebug_t *ld; 328 void *block; 329 int i, base, m; 330 331 while (ld_nfree < LD_SLOP) { 332 lockdebug_unlock(&ld_free_lk); 333 block = kmem_zalloc(LD_BATCH * sizeof(lockdebug_t), KM_SLEEP); 334 lockdebug_lock(&ld_free_lk); 335 336 if (block == NULL) 337 return; 338 339 if (ld_nfree > LD_SLOP) { 340 /* Somebody beat us to it. */ 341 lockdebug_unlock(&ld_free_lk); 342 kmem_free(block, LD_BATCH * sizeof(lockdebug_t)); 343 lockdebug_lock(&ld_free_lk); 344 continue; 345 } 346 347 base = ld_freeptr; 348 ld_nfree += LD_BATCH; 349 ld = block; 350 base <<= LD_BATCH_SHIFT; 351 m = min(LD_MAX_LOCKS, base + LD_BATCH); 352 353 if (m == LD_MAX_LOCKS) 354 ld_nomore = true; 355 356 for (i = base; i < m; i++, ld++) { 357 ld->ld_id = i; 358 TAILQ_INSERT_TAIL(&ld_free, ld, ld_chain); 359 TAILQ_INSERT_TAIL(&ld_all, ld, ld_achain); 360 } 361 362 mb_write(); 363 ld_table[ld_freeptr++] = block; 364 } 365 } 366 367 /* 368 * lockdebug_wantlock: 369 * 370 * Process the preamble to a lock acquire. 371 */ 372 void 373 lockdebug_wantlock(u_int id, uintptr_t where, int shared) 374 { 375 struct lwp *l = curlwp; 376 lockdebuglk_t *lk; 377 lockdebug_t *ld; 378 bool recurse; 379 380 (void)shared; 381 recurse = false; 382 383 if (panicstr != NULL) 384 return; 385 386 if ((ld = lockdebug_lookup(id, &lk)) == NULL) 387 return; 388 389 if ((ld->ld_flags & LD_LOCKED) != 0) { 390 if ((ld->ld_flags & LD_SLEEPER) != 0) { 391 if (ld->ld_lwp == l) 392 recurse = true; 393 } else if (ld->ld_cpu == (uint16_t)cpu_number()) 394 recurse = true; 395 } 396 397 if (shared) 398 ld->ld_shwant++; 399 else 400 ld->ld_exwant++; 401 402 if (recurse) 403 lockdebug_abort1(ld, lk, __func__, "locking against myself"); 404 405 lockdebug_unlock(lk); 406 } 407 408 /* 409 * lockdebug_locked: 410 * 411 * Process a lock acquire operation. 412 */ 413 void 414 lockdebug_locked(u_int id, uintptr_t where, int shared) 415 { 416 struct lwp *l = curlwp; 417 lockdebuglk_t *lk; 418 lockdebug_t *ld; 419 420 if (panicstr != NULL) 421 return; 422 423 if ((ld = lockdebug_lookup(id, &lk)) == NULL) 424 return; 425 426 if (shared) { 427 l->l_shlocks++; 428 ld->ld_shares++; 429 ld->ld_shwant--; 430 } else { 431 if ((ld->ld_flags & LD_LOCKED) != 0) 432 lockdebug_abort1(ld, lk, __func__, 433 "already locked"); 434 435 ld->ld_flags |= LD_LOCKED; 436 ld->ld_locked = where; 437 ld->ld_cpu = (uint16_t)cpu_number(); 438 ld->ld_lwp = l; 439 ld->ld_exwant--; 440 441 if ((ld->ld_flags & LD_SLEEPER) != 0) { 442 l->l_exlocks++; 443 TAILQ_INSERT_TAIL(&ld_sleepers, ld, ld_chain); 444 } else { 445 curcpu()->ci_spin_locks2++; 446 TAILQ_INSERT_TAIL(&ld_spinners, ld, ld_chain); 447 } 448 } 449 450 lockdebug_unlock(lk); 451 } 452 453 /* 454 * lockdebug_unlocked: 455 * 456 * Process a lock release operation. 457 */ 458 void 459 lockdebug_unlocked(u_int id, uintptr_t where, int shared) 460 { 461 struct lwp *l = curlwp; 462 lockdebuglk_t *lk; 463 lockdebug_t *ld; 464 465 if (panicstr != NULL) 466 return; 467 468 if ((ld = lockdebug_lookup(id, &lk)) == NULL) 469 return; 470 471 if (shared) { 472 if (l->l_shlocks == 0) 473 lockdebug_abort1(ld, lk, __func__, 474 "no shared locks held by LWP"); 475 if (ld->ld_shares == 0) 476 lockdebug_abort1(ld, lk, __func__, 477 "no shared holds on this lock"); 478 l->l_shlocks--; 479 ld->ld_shares--; 480 } else { 481 if ((ld->ld_flags & LD_LOCKED) == 0) 482 lockdebug_abort1(ld, lk, __func__, "not locked"); 483 484 if ((ld->ld_flags & LD_SLEEPER) != 0) { 485 if (ld->ld_lwp != curlwp) 486 lockdebug_abort1(ld, lk, __func__, 487 "not held by current LWP"); 488 ld->ld_flags &= ~LD_LOCKED; 489 ld->ld_unlocked = where; 490 ld->ld_lwp = NULL; 491 curlwp->l_exlocks--; 492 TAILQ_REMOVE(&ld_sleepers, ld, ld_chain); 493 } else { 494 if (ld->ld_cpu != (uint16_t)cpu_number()) 495 lockdebug_abort1(ld, lk, __func__, 496 "not held by current CPU"); 497 ld->ld_flags &= ~LD_LOCKED; 498 ld->ld_unlocked = where; 499 ld->ld_lwp = NULL; 500 curcpu()->ci_spin_locks2--; 501 TAILQ_REMOVE(&ld_spinners, ld, ld_chain); 502 } 503 } 504 505 lockdebug_unlock(lk); 506 } 507 508 /* 509 * lockdebug_barrier: 510 * 511 * Panic if we hold more than one specified spin lock, and optionally, 512 * if we hold sleep locks. 513 */ 514 void 515 lockdebug_barrier(volatile void *spinlock, int slplocks) 516 { 517 struct lwp *l = curlwp; 518 lockdebug_t *ld; 519 uint16_t cpuno; 520 521 if (panicstr != NULL) 522 return; 523 524 if (curcpu()->ci_spin_locks2 != 0) { 525 cpuno = (uint16_t)cpu_number(); 526 527 lockdebug_lock(&ld_spinner_lk); 528 TAILQ_FOREACH(ld, &ld_spinners, ld_chain) { 529 if (ld->ld_lock == spinlock) { 530 if (ld->ld_cpu != cpuno) 531 lockdebug_abort1(ld, &ld_spinner_lk, 532 __func__, 533 "not held by current CPU"); 534 continue; 535 } 536 if (ld->ld_cpu == cpuno) 537 lockdebug_abort1(ld, &ld_spinner_lk, 538 __func__, "spin lock held"); 539 } 540 lockdebug_unlock(&ld_spinner_lk); 541 } 542 543 if (!slplocks) { 544 if (l->l_exlocks != 0) { 545 lockdebug_lock(&ld_sleeper_lk); 546 TAILQ_FOREACH(ld, &ld_sleepers, ld_chain) { 547 if (ld->ld_lwp == l) 548 lockdebug_abort1(ld, &ld_sleeper_lk, 549 __func__, "sleep lock held"); 550 } 551 lockdebug_unlock(&ld_sleeper_lk); 552 } 553 if (l->l_shlocks != 0) 554 panic("lockdebug_barrier: holding %d shared locks", 555 l->l_shlocks); 556 } 557 } 558 559 /* 560 * lockdebug_dump: 561 * 562 * Dump information about a lock on panic, or for DDB. 563 */ 564 static void 565 lockdebug_dump(lockdebug_t *ld, void (*pr)(const char *, ...)) 566 { 567 int sleeper = (ld->ld_flags & LD_SLEEPER); 568 569 (*pr)( 570 "lock address : %#018lx type : %18s\n" 571 "shared holds : %18u exclusive: %18u\n" 572 "shares wanted: %18u exclusive: %18u\n" 573 "current cpu : %18u last held: %18u\n" 574 "current lwp : %#018lx last held: %#018lx\n" 575 "last locked : %#018lx unlocked : %#018lx\n", 576 (long)ld->ld_lock, (sleeper ? "sleep/adaptive" : "spin"), 577 (unsigned)ld->ld_shares, ((ld->ld_flags & LD_LOCKED) != 0), 578 (unsigned)ld->ld_shwant, (unsigned)ld->ld_exwant, 579 (unsigned)cpu_number(), (unsigned)ld->ld_cpu, 580 (long)curlwp, (long)ld->ld_lwp, 581 (long)ld->ld_locked, (long)ld->ld_unlocked); 582 583 if (ld->ld_lockops->lo_dump != NULL) 584 (*ld->ld_lockops->lo_dump)(ld->ld_lock); 585 586 if (sleeper) { 587 (*pr)("\n"); 588 turnstile_print(ld->ld_lock, pr); 589 } 590 } 591 592 /* 593 * lockdebug_dump: 594 * 595 * Dump information about a known lock. 596 */ 597 static void 598 lockdebug_abort1(lockdebug_t *ld, lockdebuglk_t *lk, const char *func, 599 const char *msg) 600 { 601 602 printf_nolog("%s error: %s: %s\n\n", ld->ld_lockops->lo_name, 603 func, msg); 604 lockdebug_dump(ld, printf_nolog); 605 lockdebug_unlock(lk); 606 printf_nolog("\n"); 607 panic("LOCKDEBUG"); 608 } 609 610 #endif /* LOCKDEBUG */ 611 612 /* 613 * lockdebug_lock_print: 614 * 615 * Handle the DDB 'show lock' command. 616 */ 617 #ifdef DDB 618 void 619 lockdebug_lock_print(void *addr, void (*pr)(const char *, ...)) 620 { 621 #ifdef LOCKDEBUG 622 lockdebug_t *ld; 623 624 TAILQ_FOREACH(ld, &ld_all, ld_achain) { 625 if (ld->ld_lock == addr) { 626 lockdebug_dump(ld, pr); 627 return; 628 } 629 } 630 (*pr)("Sorry, no record of a lock with address %p found.\n", addr); 631 #else 632 (*pr)("Sorry, kernel not built with the LOCKDEBUG option.\n"); 633 #endif /* LOCKDEBUG */ 634 } 635 #endif /* DDB */ 636 637 /* 638 * lockdebug_abort: 639 * 640 * An error has been trapped - dump lock info and call panic(). 641 */ 642 void 643 lockdebug_abort(u_int id, volatile void *lock, lockops_t *ops, 644 const char *func, const char *msg) 645 { 646 #ifdef LOCKDEBUG 647 lockdebug_t *ld; 648 lockdebuglk_t *lk; 649 650 if ((ld = lockdebug_lookup(id, &lk)) != NULL) { 651 lockdebug_abort1(ld, lk, func, msg); 652 /* NOTREACHED */ 653 } 654 #endif /* LOCKDEBUG */ 655 656 printf_nolog("%s error: %s: %s\n\n" 657 "lock address : %#018lx\n" 658 "current cpu : %18d\n" 659 "current lwp : %#018lx\n", 660 ops->lo_name, func, msg, (long)lock, (int)cpu_number(), 661 (long)curlwp); 662 663 (*ops->lo_dump)(lock); 664 665 printf_nolog("\n"); 666 panic("lock error"); 667 } 668
Indexes created Sun Sep 21 15:09:59 GMT 2025