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 <pzijlstr@redhat.com> 10 * 11 * Code for /proc/lockdep and /proc/lockdep_stats: 12 * 13 */ 14#include <linux/module.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 <asm/uaccess.h> 22#include <asm/div64.h> 23 24#include "lockdep_internals.h" 25 26static 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 31static void *l_start(struct seq_file *m, loff_t *pos) 32{ 33 return seq_list_start_head(&all_lock_classes, *pos); 34} 35 36static void l_stop(struct seq_file *m, void *v) 37{ 38} 39 40static void print_name(struct seq_file *m, struct lock_class *class) 41{ 42 char str[128]; 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 57static 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 96static const struct seq_operations lockdep_ops = { 97 .start = l_start, 98 .next = l_next, 99 .stop = l_stop, 100 .show = l_show, 101}; 102 103static int lockdep_open(struct inode *inode, struct file *file) 104{ 105 return seq_open(file, &lockdep_ops); 106} 107 108static 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 116static 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 127static void *lc_next(struct seq_file *m, void *v, loff_t *pos) 128{ 129 (*pos)++; 130 return lc_start(m, pos); 131} 132 133static void lc_stop(struct seq_file *m, void *v) 134{ 135} 136 137static 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 seq_printf(m, "all lock chains:\n"); 145 return 0; 146 } 147 148 seq_printf(m, "irq_context: %d\n", chain->irq_context); 149 150 for (i = 0; i < chain->depth; i++) { 151 class = lock_chain_get_class(chain, i); 152 if (!class->key) 153 continue; 154 155 seq_printf(m, "[%p] ", class->key); 156 print_name(m, class); 157 seq_puts(m, "\n"); 158 } 159 seq_puts(m, "\n"); 160 161 return 0; 162} 163 164static const struct seq_operations lockdep_chains_ops = { 165 .start = lc_start, 166 .next = lc_next, 167 .stop = lc_stop, 168 .show = lc_show, 169}; 170 171static int lockdep_chains_open(struct inode *inode, struct file *file) 172{ 173 return seq_open(file, &lockdep_chains_ops); 174} 175 176static const struct file_operations proc_lockdep_chains_operations = { 177 .open = lockdep_chains_open, 178 .read = seq_read, 179 .llseek = seq_lseek, 180 .release = seq_release, 181}; 182#endif /* CONFIG_PROVE_LOCKING */ 183 184static void lockdep_stats_debug_show(struct seq_file *m) 185{ 186#ifdef CONFIG_DEBUG_LOCKDEP 187 unsigned long long hi1 = debug_atomic_read(hardirqs_on_events), 188 hi2 = debug_atomic_read(hardirqs_off_events), 189 hr1 = debug_atomic_read(redundant_hardirqs_on), 190 hr2 = debug_atomic_read(redundant_hardirqs_off), 191 si1 = debug_atomic_read(softirqs_on_events), 192 si2 = debug_atomic_read(softirqs_off_events), 193 sr1 = debug_atomic_read(redundant_softirqs_on), 194 sr2 = debug_atomic_read(redundant_softirqs_off); 195 196 seq_printf(m, " chain lookup misses: %11llu\n", 197 debug_atomic_read(chain_lookup_misses)); 198 seq_printf(m, " chain lookup hits: %11llu\n", 199 debug_atomic_read(chain_lookup_hits)); 200 seq_printf(m, " cyclic checks: %11llu\n", 201 debug_atomic_read(nr_cyclic_checks)); 202 seq_printf(m, " find-mask forwards checks: %11llu\n", 203 debug_atomic_read(nr_find_usage_forwards_checks)); 204 seq_printf(m, " find-mask backwards checks: %11llu\n", 205 debug_atomic_read(nr_find_usage_backwards_checks)); 206 207 seq_printf(m, " hardirq on events: %11llu\n", hi1); 208 seq_printf(m, " hardirq off events: %11llu\n", hi2); 209 seq_printf(m, " redundant hardirq ons: %11llu\n", hr1); 210 seq_printf(m, " redundant hardirq offs: %11llu\n", hr2); 211 seq_printf(m, " softirq on events: %11llu\n", si1); 212 seq_printf(m, " softirq off events: %11llu\n", si2); 213 seq_printf(m, " redundant softirq ons: %11llu\n", sr1); 214 seq_printf(m, " redundant softirq offs: %11llu\n", sr2); 215#endif 216} 217 218static int lockdep_stats_show(struct seq_file *m, void *v) 219{ 220 struct lock_class *class; 221 unsigned long nr_unused = 0, nr_uncategorized = 0, 222 nr_irq_safe = 0, nr_irq_unsafe = 0, 223 nr_softirq_safe = 0, nr_softirq_unsafe = 0, 224 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0, 225 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0, 226 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0, 227 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0, 228 sum_forward_deps = 0, factor = 0; 229 230 list_for_each_entry(class, &all_lock_classes, lock_entry) { 231 232 if (class->usage_mask == 0) 233 nr_unused++; 234 if (class->usage_mask == LOCKF_USED) 235 nr_uncategorized++; 236 if (class->usage_mask & LOCKF_USED_IN_IRQ) 237 nr_irq_safe++; 238 if (class->usage_mask & LOCKF_ENABLED_IRQ) 239 nr_irq_unsafe++; 240 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) 241 nr_softirq_safe++; 242 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ) 243 nr_softirq_unsafe++; 244 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) 245 nr_hardirq_safe++; 246 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ) 247 nr_hardirq_unsafe++; 248 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ) 249 nr_irq_read_safe++; 250 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ) 251 nr_irq_read_unsafe++; 252 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) 253 nr_softirq_read_safe++; 254 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ) 255 nr_softirq_read_unsafe++; 256 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) 257 nr_hardirq_read_safe++; 258 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ) 259 nr_hardirq_read_unsafe++; 260 261#ifdef CONFIG_PROVE_LOCKING 262 sum_forward_deps += lockdep_count_forward_deps(class); 263#endif 264 } 265#ifdef CONFIG_DEBUG_LOCKDEP 266 DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused); 267#endif 268 seq_printf(m, " lock-classes: %11lu [max: %lu]\n", 269 nr_lock_classes, MAX_LOCKDEP_KEYS); 270 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n", 271 nr_list_entries, MAX_LOCKDEP_ENTRIES); 272 seq_printf(m, " indirect dependencies: %11lu\n", 273 sum_forward_deps); 274 275 /* 276 * Total number of dependencies: 277 * 278 * All irq-safe locks may nest inside irq-unsafe locks, 279 * plus all the other known dependencies: 280 */ 281 seq_printf(m, " all direct dependencies: %11lu\n", 282 nr_irq_unsafe * nr_irq_safe + 283 nr_hardirq_unsafe * nr_hardirq_safe + 284 nr_list_entries); 285 286 /* 287 * Estimated factor between direct and indirect 288 * dependencies: 289 */ 290 if (nr_list_entries) 291 factor = sum_forward_deps / nr_list_entries; 292 293#ifdef CONFIG_PROVE_LOCKING 294 seq_printf(m, " dependency chains: %11lu [max: %lu]\n", 295 nr_lock_chains, MAX_LOCKDEP_CHAINS); 296 seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n", 297 nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS); 298#endif 299 300#ifdef CONFIG_TRACE_IRQFLAGS 301 seq_printf(m, " in-hardirq chains: %11u\n", 302 nr_hardirq_chains); 303 seq_printf(m, " in-softirq chains: %11u\n", 304 nr_softirq_chains); 305#endif 306 seq_printf(m, " in-process chains: %11u\n", 307 nr_process_chains); 308 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n", 309 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES); 310 seq_printf(m, " combined max dependencies: %11u\n", 311 (nr_hardirq_chains + 1) * 312 (nr_softirq_chains + 1) * 313 (nr_process_chains + 1) 314 ); 315 seq_printf(m, " hardirq-safe locks: %11lu\n", 316 nr_hardirq_safe); 317 seq_printf(m, " hardirq-unsafe locks: %11lu\n", 318 nr_hardirq_unsafe); 319 seq_printf(m, " softirq-safe locks: %11lu\n", 320 nr_softirq_safe); 321 seq_printf(m, " softirq-unsafe locks: %11lu\n", 322 nr_softirq_unsafe); 323 seq_printf(m, " irq-safe locks: %11lu\n", 324 nr_irq_safe); 325 seq_printf(m, " irq-unsafe locks: %11lu\n", 326 nr_irq_unsafe); 327 328 seq_printf(m, " hardirq-read-safe locks: %11lu\n", 329 nr_hardirq_read_safe); 330 seq_printf(m, " hardirq-read-unsafe locks: %11lu\n", 331 nr_hardirq_read_unsafe); 332 seq_printf(m, " softirq-read-safe locks: %11lu\n", 333 nr_softirq_read_safe); 334 seq_printf(m, " softirq-read-unsafe locks: %11lu\n", 335 nr_softirq_read_unsafe); 336 seq_printf(m, " irq-read-safe locks: %11lu\n", 337 nr_irq_read_safe); 338 seq_printf(m, " irq-read-unsafe locks: %11lu\n", 339 nr_irq_read_unsafe); 340 341 seq_printf(m, " uncategorized locks: %11lu\n", 342 nr_uncategorized); 343 seq_printf(m, " unused locks: %11lu\n", 344 nr_unused); 345 seq_printf(m, " max locking depth: %11u\n", 346 max_lockdep_depth); 347#ifdef CONFIG_PROVE_LOCKING 348 seq_printf(m, " max bfs queue depth: %11u\n", 349 max_bfs_queue_depth); 350#endif 351 lockdep_stats_debug_show(m); 352 seq_printf(m, " debug_locks: %11u\n", 353 debug_locks); 354 355 return 0; 356} 357 358static int lockdep_stats_open(struct inode *inode, struct file *file) 359{ 360 return single_open(file, lockdep_stats_show, NULL); 361} 362 363static const struct file_operations proc_lockdep_stats_operations = { 364 .open = lockdep_stats_open, 365 .read = seq_read, 366 .llseek = seq_lseek, 367 .release = single_release, 368}; 369 370#ifdef CONFIG_LOCK_STAT 371 372struct lock_stat_data { 373 struct lock_class *class; 374 struct lock_class_stats stats; 375}; 376 377struct lock_stat_seq { 378 struct lock_stat_data *iter_end; 379 struct lock_stat_data stats[MAX_LOCKDEP_KEYS]; 380}; 381 382/* 383 * sort on absolute number of contentions 384 */ 385static int lock_stat_cmp(const void *l, const void *r) 386{ 387 const struct lock_stat_data *dl = l, *dr = r; 388 unsigned long nl, nr; 389 390 nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr; 391 nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr; 392 393 return nr - nl; 394} 395 396static void seq_line(struct seq_file *m, char c, int offset, int length) 397{ 398 int i; 399 400 for (i = 0; i < offset; i++) 401 seq_puts(m, " "); 402 for (i = 0; i < length; i++) 403 seq_printf(m, "%c", c); 404 seq_puts(m, "\n"); 405} 406 407static void snprint_time(char *buf, size_t bufsiz, s64 nr) 408{ 409 s64 div; 410 s32 rem; 411 412 nr += 5; /* for display rounding */ 413 div = div_s64_rem(nr, 1000, &rem); 414 snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10); 415} 416 417static void seq_time(struct seq_file *m, s64 time) 418{ 419 char num[15]; 420 421 snprint_time(num, sizeof(num), time); 422 seq_printf(m, " %14s", num); 423} 424 425static void seq_lock_time(struct seq_file *m, struct lock_time *lt) 426{ 427 seq_printf(m, "%14lu", lt->nr); 428 seq_time(m, lt->min); 429 seq_time(m, lt->max); 430 seq_time(m, lt->total); 431} 432 433static void seq_stats(struct seq_file *m, struct lock_stat_data *data) 434{ 435 char name[39]; 436 struct lock_class *class; 437 struct lock_class_stats *stats; 438 int i, namelen; 439 440 class = data->class; 441 stats = &data->stats; 442 443 namelen = 38; 444 if (class->name_version > 1) 445 namelen -= 2; 446 if (class->subclass) 447 namelen -= 2; 448 449 if (!class->name) { 450 char str[KSYM_NAME_LEN]; 451 const char *key_name; 452 453 key_name = __get_key_name(class->key, str); 454 snprintf(name, namelen, "%s", key_name); 455 } else { 456 snprintf(name, namelen, "%s", class->name); 457 } 458 namelen = strlen(name); 459 if (class->name_version > 1) { 460 snprintf(name+namelen, 3, "#%d", class->name_version); 461 namelen += 2; 462 } 463 if (class->subclass) { 464 snprintf(name+namelen, 3, "/%d", class->subclass); 465 namelen += 2; 466 } 467 468 if (stats->write_holdtime.nr) { 469 if (stats->read_holdtime.nr) 470 seq_printf(m, "%38s-W:", name); 471 else 472 seq_printf(m, "%40s:", name); 473 474 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]); 475 seq_lock_time(m, &stats->write_waittime); 476 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]); 477 seq_lock_time(m, &stats->write_holdtime); 478 seq_puts(m, "\n"); 479 } 480 481 if (stats->read_holdtime.nr) { 482 seq_printf(m, "%38s-R:", name); 483 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]); 484 seq_lock_time(m, &stats->read_waittime); 485 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]); 486 seq_lock_time(m, &stats->read_holdtime); 487 seq_puts(m, "\n"); 488 } 489 490 if (stats->read_waittime.nr + stats->write_waittime.nr == 0) 491 return; 492 493 if (stats->read_holdtime.nr) 494 namelen += 2; 495 496 for (i = 0; i < LOCKSTAT_POINTS; i++) { 497 char sym[KSYM_SYMBOL_LEN]; 498 char ip[32]; 499 500 if (class->contention_point[i] == 0) 501 break; 502 503 if (!i) 504 seq_line(m, '-', 40-namelen, namelen); 505 506 sprint_symbol(sym, class->contention_point[i]); 507 snprintf(ip, sizeof(ip), "[<%p>]", 508 (void *)class->contention_point[i]); 509 seq_printf(m, "%40s %14lu %29s %s\n", name, 510 stats->contention_point[i], 511 ip, sym); 512 } 513 for (i = 0; i < LOCKSTAT_POINTS; i++) { 514 char sym[KSYM_SYMBOL_LEN]; 515 char ip[32]; 516 517 if (class->contending_point[i] == 0) 518 break; 519 520 if (!i) 521 seq_line(m, '-', 40-namelen, namelen); 522 523 sprint_symbol(sym, class->contending_point[i]); 524 snprintf(ip, sizeof(ip), "[<%p>]", 525 (void *)class->contending_point[i]); 526 seq_printf(m, "%40s %14lu %29s %s\n", name, 527 stats->contending_point[i], 528 ip, sym); 529 } 530 if (i) { 531 seq_puts(m, "\n"); 532 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1)); 533 seq_puts(m, "\n"); 534 } 535} 536 537static void seq_header(struct seq_file *m) 538{ 539 seq_printf(m, "lock_stat version 0.3\n"); 540 541 if (unlikely(!debug_locks)) 542 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n"); 543 544 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1)); 545 seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s " 546 "%14s %14s\n", 547 "class name", 548 "con-bounces", 549 "contentions", 550 "waittime-min", 551 "waittime-max", 552 "waittime-total", 553 "acq-bounces", 554 "acquisitions", 555 "holdtime-min", 556 "holdtime-max", 557 "holdtime-total"); 558 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1)); 559 seq_printf(m, "\n"); 560} 561 562static void *ls_start(struct seq_file *m, loff_t *pos) 563{ 564 struct lock_stat_seq *data = m->private; 565 struct lock_stat_data *iter; 566 567 if (*pos == 0) 568 return SEQ_START_TOKEN; 569 570 iter = data->stats + (*pos - 1); 571 if (iter >= data->iter_end) 572 iter = NULL; 573 574 return iter; 575} 576 577static void *ls_next(struct seq_file *m, void *v, loff_t *pos) 578{ 579 (*pos)++; 580 return ls_start(m, pos); 581} 582 583static void ls_stop(struct seq_file *m, void *v) 584{ 585} 586 587static int ls_show(struct seq_file *m, void *v) 588{ 589 if (v == SEQ_START_TOKEN) 590 seq_header(m); 591 else 592 seq_stats(m, v); 593 594 return 0; 595} 596 597static const struct seq_operations lockstat_ops = { 598 .start = ls_start, 599 .next = ls_next, 600 .stop = ls_stop, 601 .show = ls_show, 602}; 603 604static int lock_stat_open(struct inode *inode, struct file *file) 605{ 606 int res; 607 struct lock_class *class; 608 struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq)); 609 610 if (!data) 611 return -ENOMEM; 612 613 res = seq_open(file, &lockstat_ops); 614 if (!res) { 615 struct lock_stat_data *iter = data->stats; 616 struct seq_file *m = file->private_data; 617 618 list_for_each_entry(class, &all_lock_classes, lock_entry) { 619 iter->class = class; 620 iter->stats = lock_stats(class); 621 iter++; 622 } 623 data->iter_end = iter; 624 625 sort(data->stats, data->iter_end - data->stats, 626 sizeof(struct lock_stat_data), 627 lock_stat_cmp, NULL); 628 629 m->private = data; 630 } else 631 vfree(data); 632 633 return res; 634} 635 636static ssize_t lock_stat_write(struct file *file, const char __user *buf, 637 size_t count, loff_t *ppos) 638{ 639 struct lock_class *class; 640 char c; 641 642 if (count) { 643 if (get_user(c, buf)) 644 return -EFAULT; 645 646 if (c != '0') 647 return count; 648 649 list_for_each_entry(class, &all_lock_classes, lock_entry) 650 clear_lock_stats(class); 651 } 652 return count; 653} 654 655static int lock_stat_release(struct inode *inode, struct file *file) 656{ 657 struct seq_file *seq = file->private_data; 658 659 vfree(seq->private); 660 return seq_release(inode, file); 661} 662 663static const struct file_operations proc_lock_stat_operations = { 664 .open = lock_stat_open, 665 .write = lock_stat_write, 666 .read = seq_read, 667 .llseek = seq_lseek, 668 .release = lock_stat_release, 669}; 670#endif /* CONFIG_LOCK_STAT */ 671 672static int __init lockdep_proc_init(void) 673{ 674 proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations); 675#ifdef CONFIG_PROVE_LOCKING 676 proc_create("lockdep_chains", S_IRUSR, NULL, 677 &proc_lockdep_chains_operations); 678#endif 679 proc_create("lockdep_stats", S_IRUSR, NULL, 680 &proc_lockdep_stats_operations); 681 682#ifdef CONFIG_LOCK_STAT 683 proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, 684 &proc_lock_stat_operations); 685#endif 686 687 return 0; 688} 689 690__initcall(lockdep_proc_init); 691