1 /* 2 * kernel/lockdep_proc.c 3 * 4 * Runtime locking correctness validator 5 * 6 * Started by Ingo Molnar: 7 * 8 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> 9 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra 10 * 11 * Code for /proc/lockdep and /proc/lockdep_stats: 12 * 13 */ 14 #include <linux/export.h> 15 #include <linux/proc_fs.h> 16 #include <linux/seq_file.h> 17 #include <linux/kallsyms.h> 18 #include <linux/debug_locks.h> 19 #include <linux/vmalloc.h> 20 #include <linux/sort.h> 21 #include <linux/uaccess.h> 22 #include <asm/div64.h> 23 24 #include "lockdep_internals.h" 25 26 static void *l_next(struct seq_file *m, void *v, loff_t *pos) 27 { 28 return seq_list_next(v, &all_lock_classes, pos); 29 } 30 31 static void *l_start(struct seq_file *m, loff_t *pos) 32 { 33 return seq_list_start_head(&all_lock_classes, *pos); 34 } 35 36 static void l_stop(struct seq_file *m, void *v) 37 { 38 } 39 40 static void print_name(struct seq_file *m, struct lock_class *class) 41 { 42 char str[KSYM_NAME_LEN]; 43 const char *name = class->name; 44 45 if (!name) { 46 name = __get_key_name(class->key, str); 47 seq_printf(m, "%s", name); 48 } else{ 49 seq_printf(m, "%s", name); 50 if (class->name_version > 1) 51 seq_printf(m, "#%d", class->name_version); 52 if (class->subclass) 53 seq_printf(m, "/%d", class->subclass); 54 } 55 } 56 57 static int l_show(struct seq_file *m, void *v) 58 { 59 struct lock_class *class = list_entry(v, struct lock_class, lock_entry); 60 struct lock_list *entry; 61 char usage[LOCK_USAGE_CHARS]; 62 63 if (v == &all_lock_classes) { 64 seq_printf(m, "all lock classes:\n"); 65 return 0; 66 } 67 68 seq_printf(m, "%p", class->key); 69 #ifdef CONFIG_DEBUG_LOCKDEP 70 seq_printf(m, " OPS:%8ld", class->ops); 71 #endif 72 #ifdef CONFIG_PROVE_LOCKING 73 seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class)); 74 seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class)); 75 #endif 76 77 get_usage_chars(class, usage); 78 seq_printf(m, " %s", usage); 79 80 seq_printf(m, ": "); 81 print_name(m, class); 82 seq_puts(m, "\n"); 83 84 list_for_each_entry(entry, &class->locks_after, entry) { 85 if (entry->distance == 1) { 86 seq_printf(m, " -> [%p] ", entry->class->key); 87 print_name(m, entry->class); 88 seq_puts(m, "\n"); 89 } 90 } 91 seq_puts(m, "\n"); 92 93 return 0; 94 } 95 96 static const struct seq_operations lockdep_ops = { 97 .start = l_start, 98 .next = l_next, 99 .stop = l_stop, 100 .show = l_show, 101 }; 102 103 static int lockdep_open(struct inode *inode, struct file *file) 104 { 105 return seq_open(file, &lockdep_ops); 106 } 107 108 static const struct file_operations proc_lockdep_operations = { 109 .open = lockdep_open, 110 .read = seq_read, 111 .llseek = seq_lseek, 112 .release = seq_release, 113 }; 114 115 #ifdef CONFIG_PROVE_LOCKING 116 static void *lc_start(struct seq_file *m, loff_t *pos) 117 { 118 if (*pos == 0) 119 return SEQ_START_TOKEN; 120 121 if (*pos - 1 < nr_lock_chains) 122 return lock_chains + (*pos - 1); 123 124 return NULL; 125 } 126 127 static void *lc_next(struct seq_file *m, void *v, loff_t *pos) 128 { 129 (*pos)++; 130 return lc_start(m, pos); 131 } 132 133 static void lc_stop(struct seq_file *m, void *v) 134 { 135 } 136 137 static int lc_show(struct seq_file *m, void *v) 138 { 139 struct lock_chain *chain = v; 140 struct lock_class *class; 141 int i; 142 143 if (v == SEQ_START_TOKEN) { 144 if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS) 145 seq_printf(m, "(buggered) "); 146 seq_printf(m, "all lock chains:\n"); 147 return 0; 148 } 149 150 seq_printf(m, "irq_context: %d\n", chain->irq_context); 151 152 for (i = 0; i < chain->depth; i++) { 153 class = lock_chain_get_class(chain, i); 154 if (!class->key) 155 continue; 156 157 seq_printf(m, "[%p] ", class->key); 158 print_name(m, class); 159 seq_puts(m, "\n"); 160 } 161 seq_puts(m, "\n"); 162 163 return 0; 164 } 165 166 static const struct seq_operations lockdep_chains_ops = { 167 .start = lc_start, 168 .next = lc_next, 169 .stop = lc_stop, 170 .show = lc_show, 171 }; 172 173 static int lockdep_chains_open(struct inode *inode, struct file *file) 174 { 175 return seq_open(file, &lockdep_chains_ops); 176 } 177 178 static const struct file_operations proc_lockdep_chains_operations = { 179 .open = lockdep_chains_open, 180 .read = seq_read, 181 .llseek = seq_lseek, 182 .release = seq_release, 183 }; 184 #endif /* CONFIG_PROVE_LOCKING */ 185 186 static void lockdep_stats_debug_show(struct seq_file *m) 187 { 188 #ifdef CONFIG_DEBUG_LOCKDEP 189 unsigned long long hi1 = debug_atomic_read(hardirqs_on_events), 190 hi2 = debug_atomic_read(hardirqs_off_events), 191 hr1 = debug_atomic_read(redundant_hardirqs_on), 192 hr2 = debug_atomic_read(redundant_hardirqs_off), 193 si1 = debug_atomic_read(softirqs_on_events), 194 si2 = debug_atomic_read(softirqs_off_events), 195 sr1 = debug_atomic_read(redundant_softirqs_on), 196 sr2 = debug_atomic_read(redundant_softirqs_off); 197 198 seq_printf(m, " chain lookup misses: %11llu\n", 199 debug_atomic_read(chain_lookup_misses)); 200 seq_printf(m, " chain lookup hits: %11llu\n", 201 debug_atomic_read(chain_lookup_hits)); 202 seq_printf(m, " cyclic checks: %11llu\n", 203 debug_atomic_read(nr_cyclic_checks)); 204 seq_printf(m, " redundant checks: %11llu\n", 205 debug_atomic_read(nr_redundant_checks)); 206 seq_printf(m, " redundant links: %11llu\n", 207 debug_atomic_read(nr_redundant)); 208 seq_printf(m, " find-mask forwards checks: %11llu\n", 209 debug_atomic_read(nr_find_usage_forwards_checks)); 210 seq_printf(m, " find-mask backwards checks: %11llu\n", 211 debug_atomic_read(nr_find_usage_backwards_checks)); 212 213 seq_printf(m, " hardirq on events: %11llu\n", hi1); 214 seq_printf(m, " hardirq off events: %11llu\n", hi2); 215 seq_printf(m, " redundant hardirq ons: %11llu\n", hr1); 216 seq_printf(m, " redundant hardirq offs: %11llu\n", hr2); 217 seq_printf(m, " softirq on events: %11llu\n", si1); 218 seq_printf(m, " softirq off events: %11llu\n", si2); 219 seq_printf(m, " redundant softirq ons: %11llu\n", sr1); 220 seq_printf(m, " redundant softirq offs: %11llu\n", sr2); 221 #endif 222 } 223 224 static int lockdep_stats_show(struct seq_file *m, void *v) 225 { 226 struct lock_class *class; 227 unsigned long nr_unused = 0, nr_uncategorized = 0, 228 nr_irq_safe = 0, nr_irq_unsafe = 0, 229 nr_softirq_safe = 0, nr_softirq_unsafe = 0, 230 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0, 231 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0, 232 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0, 233 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0, 234 sum_forward_deps = 0; 235 236 list_for_each_entry(class, &all_lock_classes, lock_entry) { 237 238 if (class->usage_mask == 0) 239 nr_unused++; 240 if (class->usage_mask == LOCKF_USED) 241 nr_uncategorized++; 242 if (class->usage_mask & LOCKF_USED_IN_IRQ) 243 nr_irq_safe++; 244 if (class->usage_mask & LOCKF_ENABLED_IRQ) 245 nr_irq_unsafe++; 246 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) 247 nr_softirq_safe++; 248 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ) 249 nr_softirq_unsafe++; 250 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) 251 nr_hardirq_safe++; 252 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ) 253 nr_hardirq_unsafe++; 254 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ) 255 nr_irq_read_safe++; 256 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ) 257 nr_irq_read_unsafe++; 258 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) 259 nr_softirq_read_safe++; 260 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) 261 nr_softirq_read_unsafe++; 262 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) 263 nr_hardirq_read_safe++; 264 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) 265 nr_hardirq_read_unsafe++; 266 267 #ifdef CONFIG_PROVE_LOCKING 268 sum_forward_deps += lockdep_count_forward_deps(class); 269 #endif 270 } 271 #ifdef CONFIG_DEBUG_LOCKDEP 272 DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused); 273 #endif 274 seq_printf(m, " lock-classes: %11lu [max: %lu]\n", 275 nr_lock_classes, MAX_LOCKDEP_KEYS); 276 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n", 277 nr_list_entries, MAX_LOCKDEP_ENTRIES); 278 seq_printf(m, " indirect dependencies: %11lu\n", 279 sum_forward_deps); 280 281 /* 282 * Total number of dependencies: 283 * 284 * All irq-safe locks may nest inside irq-unsafe locks, 285 * plus all the other known dependencies: 286 */ 287 seq_printf(m, " all direct dependencies: %11lu\n", 288 nr_irq_unsafe * nr_irq_safe + 289 nr_hardirq_unsafe * nr_hardirq_safe + 290 nr_list_entries); 291 292 #ifdef CONFIG_PROVE_LOCKING 293 seq_printf(m, " dependency chains: %11lu [max: %lu]\n", 294 nr_lock_chains, MAX_LOCKDEP_CHAINS); 295 seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n", 296 nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS); 297 #endif 298 299 #ifdef CONFIG_TRACE_IRQFLAGS 300 seq_printf(m, " in-hardirq chains: %11u\n", 301 nr_hardirq_chains); 302 seq_printf(m, " in-softirq chains: %11u\n", 303 nr_softirq_chains); 304 #endif 305 seq_printf(m, " in-process chains: %11u\n", 306 nr_process_chains); 307 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n", 308 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES); 309 seq_printf(m, " combined max dependencies: %11u\n", 310 (nr_hardirq_chains + 1) * 311 (nr_softirq_chains + 1) * 312 (nr_process_chains + 1) 313 ); 314 seq_printf(m, " hardirq-safe locks: %11lu\n", 315 nr_hardirq_safe); 316 seq_printf(m, " hardirq-unsafe locks: %11lu\n", 317 nr_hardirq_unsafe); 318 seq_printf(m, " softirq-safe locks: %11lu\n", 319 nr_softirq_safe); 320 seq_printf(m, " softirq-unsafe locks: %11lu\n", 321 nr_softirq_unsafe); 322 seq_printf(m, " irq-safe locks: %11lu\n", 323 nr_irq_safe); 324 seq_printf(m, " irq-unsafe locks: %11lu\n", 325 nr_irq_unsafe); 326 327 seq_printf(m, " hardirq-read-safe locks: %11lu\n", 328 nr_hardirq_read_safe); 329 seq_printf(m, " hardirq-read-unsafe locks: %11lu\n", 330 nr_hardirq_read_unsafe); 331 seq_printf(m, " softirq-read-safe locks: %11lu\n", 332 nr_softirq_read_safe); 333 seq_printf(m, " softirq-read-unsafe locks: %11lu\n", 334 nr_softirq_read_unsafe); 335 seq_printf(m, " irq-read-safe locks: %11lu\n", 336 nr_irq_read_safe); 337 seq_printf(m, " irq-read-unsafe locks: %11lu\n", 338 nr_irq_read_unsafe); 339 340 seq_printf(m, " uncategorized locks: %11lu\n", 341 nr_uncategorized); 342 seq_printf(m, " unused locks: %11lu\n", 343 nr_unused); 344 seq_printf(m, " max locking depth: %11u\n", 345 max_lockdep_depth); 346 #ifdef CONFIG_PROVE_LOCKING 347 seq_printf(m, " max bfs queue depth: %11u\n", 348 max_bfs_queue_depth); 349 #endif 350 lockdep_stats_debug_show(m); 351 seq_printf(m, " debug_locks: %11u\n", 352 debug_locks); 353 354 return 0; 355 } 356 357 static int lockdep_stats_open(struct inode *inode, struct file *file) 358 { 359 return single_open(file, lockdep_stats_show, NULL); 360 } 361 362 static const struct file_operations proc_lockdep_stats_operations = { 363 .open = lockdep_stats_open, 364 .read = seq_read, 365 .llseek = seq_lseek, 366 .release = single_release, 367 }; 368 369 #ifdef CONFIG_LOCK_STAT 370 371 struct lock_stat_data { 372 struct lock_class *class; 373 struct lock_class_stats stats; 374 }; 375 376 struct lock_stat_seq { 377 struct lock_stat_data *iter_end; 378 struct lock_stat_data stats[MAX_LOCKDEP_KEYS]; 379 }; 380 381 /* 382 * sort on absolute number of contentions 383 */ 384 static int lock_stat_cmp(const void *l, const void *r) 385 { 386 const struct lock_stat_data *dl = l, *dr = r; 387 unsigned long nl, nr; 388 389 nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr; 390 nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr; 391 392 return nr - nl; 393 } 394 395 static void seq_line(struct seq_file *m, char c, int offset, int length) 396 { 397 int i; 398 399 for (i = 0; i < offset; i++) 400 seq_puts(m, " "); 401 for (i = 0; i < length; i++) 402 seq_printf(m, "%c", c); 403 seq_puts(m, "\n"); 404 } 405 406 static void snprint_time(char *buf, size_t bufsiz, s64 nr) 407 { 408 s64 div; 409 s32 rem; 410 411 nr += 5; /* for display rounding */ 412 div = div_s64_rem(nr, 1000, &rem); 413 snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10); 414 } 415 416 static void seq_time(struct seq_file *m, s64 time) 417 { 418 char num[15]; 419 420 snprint_time(num, sizeof(num), time); 421 seq_printf(m, " %14s", num); 422 } 423 424 static void seq_lock_time(struct seq_file *m, struct lock_time *lt) 425 { 426 seq_printf(m, "%14lu", lt->nr); 427 seq_time(m, lt->min); 428 seq_time(m, lt->max); 429 seq_time(m, lt->total); 430 seq_time(m, lt->nr ? div_s64(lt->total, lt->nr) : 0); 431 } 432 433 static void seq_stats(struct seq_file *m, struct lock_stat_data *data) 434 { 435 struct lockdep_subclass_key *ckey; 436 struct lock_class_stats *stats; 437 struct lock_class *class; 438 const char *cname; 439 int i, namelen; 440 char name[39]; 441 442 class = data->class; 443 stats = &data->stats; 444 445 namelen = 38; 446 if (class->name_version > 1) 447 namelen -= 2; /* XXX truncates versions > 9 */ 448 if (class->subclass) 449 namelen -= 2; 450 451 rcu_read_lock_sched(); 452 cname = rcu_dereference_sched(class->name); 453 ckey = rcu_dereference_sched(class->key); 454 455 if (!cname && !ckey) { 456 rcu_read_unlock_sched(); 457 return; 458 459 } else if (!cname) { 460 char str[KSYM_NAME_LEN]; 461 const char *key_name; 462 463 key_name = __get_key_name(ckey, str); 464 snprintf(name, namelen, "%s", key_name); 465 } else { 466 snprintf(name, namelen, "%s", cname); 467 } 468 rcu_read_unlock_sched(); 469 470 namelen = strlen(name); 471 if (class->name_version > 1) { 472 snprintf(name+namelen, 3, "#%d", class->name_version); 473 namelen += 2; 474 } 475 if (class->subclass) { 476 snprintf(name+namelen, 3, "/%d", class->subclass); 477 namelen += 2; 478 } 479 480 if (stats->write_holdtime.nr) { 481 if (stats->read_holdtime.nr) 482 seq_printf(m, "%38s-W:", name); 483 else 484 seq_printf(m, "%40s:", name); 485 486 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]); 487 seq_lock_time(m, &stats->write_waittime); 488 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]); 489 seq_lock_time(m, &stats->write_holdtime); 490 seq_puts(m, "\n"); 491 } 492 493 if (stats->read_holdtime.nr) { 494 seq_printf(m, "%38s-R:", name); 495 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]); 496 seq_lock_time(m, &stats->read_waittime); 497 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]); 498 seq_lock_time(m, &stats->read_holdtime); 499 seq_puts(m, "\n"); 500 } 501 502 if (stats->read_waittime.nr + stats->write_waittime.nr == 0) 503 return; 504 505 if (stats->read_holdtime.nr) 506 namelen += 2; 507 508 for (i = 0; i < LOCKSTAT_POINTS; i++) { 509 char ip[32]; 510 511 if (class->contention_point[i] == 0) 512 break; 513 514 if (!i) 515 seq_line(m, '-', 40-namelen, namelen); 516 517 snprintf(ip, sizeof(ip), "[<%p>]", 518 (void *)class->contention_point[i]); 519 seq_printf(m, "%40s %14lu %29s %pS\n", 520 name, stats->contention_point[i], 521 ip, (void *)class->contention_point[i]); 522 } 523 for (i = 0; i < LOCKSTAT_POINTS; i++) { 524 char ip[32]; 525 526 if (class->contending_point[i] == 0) 527 break; 528 529 if (!i) 530 seq_line(m, '-', 40-namelen, namelen); 531 532 snprintf(ip, sizeof(ip), "[<%p>]", 533 (void *)class->contending_point[i]); 534 seq_printf(m, "%40s %14lu %29s %pS\n", 535 name, stats->contending_point[i], 536 ip, (void *)class->contending_point[i]); 537 } 538 if (i) { 539 seq_puts(m, "\n"); 540 seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1)); 541 seq_puts(m, "\n"); 542 } 543 } 544 545 static void seq_header(struct seq_file *m) 546 { 547 seq_puts(m, "lock_stat version 0.4\n"); 548 549 if (unlikely(!debug_locks)) 550 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n"); 551 552 seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1)); 553 seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s " 554 "%14s %14s\n", 555 "class name", 556 "con-bounces", 557 "contentions", 558 "waittime-min", 559 "waittime-max", 560 "waittime-total", 561 "waittime-avg", 562 "acq-bounces", 563 "acquisitions", 564 "holdtime-min", 565 "holdtime-max", 566 "holdtime-total", 567 "holdtime-avg"); 568 seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1)); 569 seq_printf(m, "\n"); 570 } 571 572 static void *ls_start(struct seq_file *m, loff_t *pos) 573 { 574 struct lock_stat_seq *data = m->private; 575 struct lock_stat_data *iter; 576 577 if (*pos == 0) 578 return SEQ_START_TOKEN; 579 580 iter = data->stats + (*pos - 1); 581 if (iter >= data->iter_end) 582 iter = NULL; 583 584 return iter; 585 } 586 587 static void *ls_next(struct seq_file *m, void *v, loff_t *pos) 588 { 589 (*pos)++; 590 return ls_start(m, pos); 591 } 592 593 static void ls_stop(struct seq_file *m, void *v) 594 { 595 } 596 597 static int ls_show(struct seq_file *m, void *v) 598 { 599 if (v == SEQ_START_TOKEN) 600 seq_header(m); 601 else 602 seq_stats(m, v); 603 604 return 0; 605 } 606 607 static const struct seq_operations lockstat_ops = { 608 .start = ls_start, 609 .next = ls_next, 610 .stop = ls_stop, 611 .show = ls_show, 612 }; 613 614 static int lock_stat_open(struct inode *inode, struct file *file) 615 { 616 int res; 617 struct lock_class *class; 618 struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq)); 619 620 if (!data) 621 return -ENOMEM; 622 623 res = seq_open(file, &lockstat_ops); 624 if (!res) { 625 struct lock_stat_data *iter = data->stats; 626 struct seq_file *m = file->private_data; 627 628 list_for_each_entry(class, &all_lock_classes, lock_entry) { 629 iter->class = class; 630 iter->stats = lock_stats(class); 631 iter++; 632 } 633 data->iter_end = iter; 634 635 sort(data->stats, data->iter_end - data->stats, 636 sizeof(struct lock_stat_data), 637 lock_stat_cmp, NULL); 638 639 m->private = data; 640 } else 641 vfree(data); 642 643 return res; 644 } 645 646 static ssize_t lock_stat_write(struct file *file, const char __user *buf, 647 size_t count, loff_t *ppos) 648 { 649 struct lock_class *class; 650 char c; 651 652 if (count) { 653 if (get_user(c, buf)) 654 return -EFAULT; 655 656 if (c != '0') 657 return count; 658 659 list_for_each_entry(class, &all_lock_classes, lock_entry) 660 clear_lock_stats(class); 661 } 662 return count; 663 } 664 665 static int lock_stat_release(struct inode *inode, struct file *file) 666 { 667 struct seq_file *seq = file->private_data; 668 669 vfree(seq->private); 670 return seq_release(inode, file); 671 } 672 673 static const struct file_operations proc_lock_stat_operations = { 674 .open = lock_stat_open, 675 .write = lock_stat_write, 676 .read = seq_read, 677 .llseek = seq_lseek, 678 .release = lock_stat_release, 679 }; 680 #endif /* CONFIG_LOCK_STAT */ 681 682 static int __init lockdep_proc_init(void) 683 { 684 proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations); 685 #ifdef CONFIG_PROVE_LOCKING 686 proc_create("lockdep_chains", S_IRUSR, NULL, 687 &proc_lockdep_chains_operations); 688 #endif 689 proc_create("lockdep_stats", S_IRUSR, NULL, 690 &proc_lockdep_stats_operations); 691 692 #ifdef CONFIG_LOCK_STAT 693 proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, 694 &proc_lock_stat_operations); 695 #endif 696 697 return 0; 698 } 699 700 __initcall(lockdep_proc_init); 701 702