kernel/lockdep_proc.c

   1 /*
   2  * kernel/lockdep_proc.c
   3  *
   4  * Runtime locking correctness validator
   5  *
   6  * Started by Ingo Molnar:
   7  *
   8  *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
   9  *
  10  * Code for /proc/lockdep and /proc/lockdep_stats:
  11  *
  12  */
  13 #include <linux/module.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/kallsyms.h>
  17 #include <linux/debug_locks.h>
  18 #include <linux/vmalloc.h>
  19 #include <linux/sort.h>
  20 #include <asm/uaccess.h>
  21 #include <asm/div64.h>
  22
  23 #include "lockdep_internals.h"
  24
  25 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
  26 {
  27         struct lock_class *class = v;
  28
  29         (*pos)++;
  30
  31         if (class->lock_entry.next != &all_lock_classes)
  32                 class = list_entry(class->lock_entry.next, struct lock_class,
  33                                   lock_entry);
  34         else
  35                 class = NULL;
  36         m->private = class;
  37
  38         return class;
  39 }
  40
  41 static void *l_start(struct seq_file *m, loff_t *pos)
  42 {
  43         struct lock_class *class = m->private;
  44
  45         if (&class->lock_entry == all_lock_classes.next)
  46                 seq_printf(m, "all lock classes:\n");
  47
  48         return class;
  49 }
  50
  51 static void l_stop(struct seq_file *m, void *v)
  52 {
  53 }
  54
  55 static unsigned long count_forward_deps(struct lock_class *class)
  56 {
  57         struct lock_list *entry;
  58         unsigned long ret = 1;
  59
  60         /*
  61          * Recurse this class's dependency list:
  62          */
  63         list_for_each_entry(entry, &class->locks_after, entry)
  64                 ret += count_forward_deps(entry->class);
  65
  66         return ret;
  67 }
  68
  69 static unsigned long count_backward_deps(struct lock_class *class)
  70 {
  71         struct lock_list *entry;
  72         unsigned long ret = 1;
  73
  74         /*
  75          * Recurse this class's dependency list:
  76          */
  77         list_for_each_entry(entry, &class->locks_before, entry)
  78                 ret += count_backward_deps(entry->class);
  79
  80         return ret;
  81 }
  82
  83 static void print_name(struct seq_file *m, struct lock_class *class)
  84 {
  85         char str[128];
  86         const char *name = class->name;
  87
  88         if (!name) {
  89                 name = __get_key_name(class->key, str);
  90                 seq_printf(m, "%s", name);
  91         } else{
  92                 seq_printf(m, "%s", name);
  93                 if (class->name_version > 1)
  94                         seq_printf(m, "#%d", class->name_version);
  95                 if (class->subclass)
  96                         seq_printf(m, "/%d", class->subclass);
  97         }
  98 }
  99
 100 static int l_show(struct seq_file *m, void *v)
 101 {
 102         unsigned long nr_forward_deps, nr_backward_deps;
 103         struct lock_class *class = m->private;
 104         struct lock_list *entry;
 105         char c1, c2, c3, c4;
 106
 107         seq_printf(m, "%p", class->key);
 108 #ifdef CONFIG_DEBUG_LOCKDEP
 109         seq_printf(m, " OPS:%8ld", class->ops);
 110 #endif
 111         nr_forward_deps = count_forward_deps(class);
 112         seq_printf(m, " FD:%5ld", nr_forward_deps);
 113
 114         nr_backward_deps = count_backward_deps(class);
 115         seq_printf(m, " BD:%5ld", nr_backward_deps);
 116
 117         get_usage_chars(class, &c1, &c2, &c3, &c4);
 118         seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
 119
 120         seq_printf(m, ": ");
 121         print_name(m, class);
 122         seq_puts(m, "\n");
 123
 124         list_for_each_entry(entry, &class->locks_after, entry) {
 125                 if (entry->distance == 1) {
 126                         seq_printf(m, " -> [%p] ", entry->class);
 127                         print_name(m, entry->class);
 128                         seq_puts(m, "\n");
 129                 }
 130         }
 131         seq_puts(m, "\n");
 132
 133         return 0;
 134 }
 135
 136 static const struct seq_operations lockdep_ops = {
 137         .start  = l_start,
 138         .next   = l_next,
 139         .stop   = l_stop,
 140         .show   = l_show,
 141 };
 142
 143 static int lockdep_open(struct inode *inode, struct file *file)
 144 {
 145         int res = seq_open(file, &lockdep_ops);
 146         if (!res) {
 147                 struct seq_file *m = file->private_data;
 148
 149                 if (!list_empty(&all_lock_classes))
 150                         m->private = list_entry(all_lock_classes.next,
 151                                         struct lock_class, lock_entry);
 152                 else
 153                         m->private = NULL;
 154         }
 155         return res;
 156 }
 157
 158 static const struct file_operations proc_lockdep_operations = {
 159         .open           = lockdep_open,
 160         .read           = seq_read,
 161         .llseek         = seq_lseek,
 162         .release        = seq_release,
 163 };
 164
 165 static void lockdep_stats_debug_show(struct seq_file *m)
 166 {
 167 #ifdef CONFIG_DEBUG_LOCKDEP
 168         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
 169                      hi2 = debug_atomic_read(&hardirqs_off_events),
 170                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
 171                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
 172                      si1 = debug_atomic_read(&softirqs_on_events),
 173                      si2 = debug_atomic_read(&softirqs_off_events),
 174                      sr1 = debug_atomic_read(&redundant_softirqs_on),
 175                      sr2 = debug_atomic_read(&redundant_softirqs_off);
 176
 177         seq_printf(m, " chain lookup misses:           %11u\n",
 178                 debug_atomic_read(&chain_lookup_misses));
 179         seq_printf(m, " chain lookup hits:             %11u\n",
 180                 debug_atomic_read(&chain_lookup_hits));
 181         seq_printf(m, " cyclic checks:                 %11u\n",
 182                 debug_atomic_read(&nr_cyclic_checks));
 183         seq_printf(m, " cyclic-check recursions:       %11u\n",
 184                 debug_atomic_read(&nr_cyclic_check_recursions));
 185         seq_printf(m, " find-mask forwards checks:     %11u\n",
 186                 debug_atomic_read(&nr_find_usage_forwards_checks));
 187         seq_printf(m, " find-mask forwards recursions: %11u\n",
 188                 debug_atomic_read(&nr_find_usage_forwards_recursions));
 189         seq_printf(m, " find-mask backwards checks:    %11u\n",
 190                 debug_atomic_read(&nr_find_usage_backwards_checks));
 191         seq_printf(m, " find-mask backwards recursions:%11u\n",
 192                 debug_atomic_read(&nr_find_usage_backwards_recursions));
 193
 194         seq_printf(m, " hardirq on events:             %11u\n", hi1);
 195         seq_printf(m, " hardirq off events:            %11u\n", hi2);
 196         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
 197         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
 198         seq_printf(m, " softirq on events:             %11u\n", si1);
 199         seq_printf(m, " softirq off events:            %11u\n", si2);
 200         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
 201         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
 202 #endif
 203 }
 204
 205 static int lockdep_stats_show(struct seq_file *m, void *v)
 206 {
 207         struct lock_class *class;
 208         unsigned long nr_unused = 0, nr_uncategorized = 0,
 209                       nr_irq_safe = 0, nr_irq_unsafe = 0,
 210                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
 211                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
 212                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
 213                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
 214                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
 215                       sum_forward_deps = 0, factor = 0;
 216
 217         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 218
 219                 if (class->usage_mask == 0)
 220                         nr_unused++;
 221                 if (class->usage_mask == LOCKF_USED)
 222                         nr_uncategorized++;
 223                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 224                         nr_irq_safe++;
 225                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
 226                         nr_irq_unsafe++;
 227                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 228                         nr_softirq_safe++;
 229                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
 230                         nr_softirq_unsafe++;
 231                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 232                         nr_hardirq_safe++;
 233                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
 234                         nr_hardirq_unsafe++;
 235                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 236                         nr_irq_read_safe++;
 237                 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
 238                         nr_irq_read_unsafe++;
 239                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 240                         nr_softirq_read_safe++;
 241                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
 242                         nr_softirq_read_unsafe++;
 243                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 244                         nr_hardirq_read_safe++;
 245                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
 246                         nr_hardirq_read_unsafe++;
 247
 248                 sum_forward_deps += count_forward_deps(class);
 249         }
 250 #ifdef CONFIG_DEBUG_LOCKDEP
 251         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
 252 #endif
 253         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 254                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 255         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 256                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 257         seq_printf(m, " indirect dependencies:         %11lu\n",
 258                         sum_forward_deps);
 259
 260         /*
 261          * Total number of dependencies:
 262          *
 263          * All irq-safe locks may nest inside irq-unsafe locks,
 264          * plus all the other known dependencies:
 265          */
 266         seq_printf(m, " all direct dependencies:       %11lu\n",
 267                         nr_irq_unsafe * nr_irq_safe +
 268                         nr_hardirq_unsafe * nr_hardirq_safe +
 269                         nr_list_entries);
 270
 271         /*
 272          * Estimated factor between direct and indirect
 273          * dependencies:
 274          */
 275         if (nr_list_entries)
 276                 factor = sum_forward_deps / nr_list_entries;
 277
 278 #ifdef CONFIG_PROVE_LOCKING
 279         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 280                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 281 #endif
 282
 283 #ifdef CONFIG_TRACE_IRQFLAGS
 284         seq_printf(m, " in-hardirq chains:             %11u\n",
 285                         nr_hardirq_chains);
 286         seq_printf(m, " in-softirq chains:             %11u\n",
 287                         nr_softirq_chains);
 288 #endif
 289         seq_printf(m, " in-process chains:             %11u\n",
 290                         nr_process_chains);
 291         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 292                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 293         seq_printf(m, " combined max dependencies:     %11u\n",
 294                         (nr_hardirq_chains + 1) *
 295                         (nr_softirq_chains + 1) *
 296                         (nr_process_chains + 1)
 297         );
 298         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 299                         nr_hardirq_safe);
 300         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 301                         nr_hardirq_unsafe);
 302         seq_printf(m, " softirq-safe locks:            %11lu\n",
 303                         nr_softirq_safe);
 304         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 305                         nr_softirq_unsafe);
 306         seq_printf(m, " irq-safe locks:                %11lu\n",
 307                         nr_irq_safe);
 308         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 309                         nr_irq_unsafe);
 310
 311         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 312                         nr_hardirq_read_safe);
 313         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 314                         nr_hardirq_read_unsafe);
 315         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 316                         nr_softirq_read_safe);
 317         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 318                         nr_softirq_read_unsafe);
 319         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 320                         nr_irq_read_safe);
 321         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 322                         nr_irq_read_unsafe);
 323
 324         seq_printf(m, " uncategorized locks:           %11lu\n",
 325                         nr_uncategorized);
 326         seq_printf(m, " unused locks:                  %11lu\n",
 327                         nr_unused);
 328         seq_printf(m, " max locking depth:             %11u\n",
 329                         max_lockdep_depth);
 330         seq_printf(m, " max recursion depth:           %11u\n",
 331                         max_recursion_depth);
 332         lockdep_stats_debug_show(m);
 333         seq_printf(m, " debug_locks:                   %11u\n",
 334                         debug_locks);
 335
 336         return 0;
 337 }
 338
 339 static int lockdep_stats_open(struct inode *inode, struct file *file)
 340 {
 341         return single_open(file, lockdep_stats_show, NULL);
 342 }
 343
 344 static const struct file_operations proc_lockdep_stats_operations = {
 345         .open           = lockdep_stats_open,
 346         .read           = seq_read,
 347         .llseek         = seq_lseek,
 348         .release        = seq_release,
 349 };
 350
 351 #ifdef CONFIG_LOCK_STAT
 352
 353 struct lock_stat_data {
 354         struct lock_class *class;
 355         struct lock_class_stats stats;
 356 };
 357
 358 struct lock_stat_seq {
 359         struct lock_stat_data *iter;
 360         struct lock_stat_data *iter_end;
 361         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
 362 };
 363
 364 /*
 365  * sort on absolute number of contentions
 366  */
 367 static int lock_stat_cmp(const void *l, const void *r)
 368 {
 369         const struct lock_stat_data *dl = l, *dr = r;
 370         unsigned long nl, nr;
 371
 372         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
 373         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
 374
 375         return nr - nl;
 376 }
 377
 378 static void seq_line(struct seq_file *m, char c, int offset, int length)
 379 {
 380         int i;
 381
 382         for (i = 0; i < offset; i++)
 383                 seq_puts(m, " ");
 384         for (i = 0; i < length; i++)
 385                 seq_printf(m, "%c", c);
 386         seq_puts(m, "\n");
 387 }
 388
 389 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
 390 {
 391         unsigned long rem;
 392
 393         rem = do_div(nr, 1000); /* XXX: do_div_signed */
 394         snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
 395 }
 396
 397 static void seq_time(struct seq_file *m, s64 time)
 398 {
 399         char num[15];
 400
 401         snprint_time(num, sizeof(num), time);
 402         seq_printf(m, " %14s", num);
 403 }
 404
 405 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 406 {
 407         seq_printf(m, "%14lu", lt->nr);
 408         seq_time(m, lt->min);
 409         seq_time(m, lt->max);
 410         seq_time(m, lt->total);
 411 }
 412
 413 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 414 {
 415         char name[39];
 416         struct lock_class *class;
 417         struct lock_class_stats *stats;
 418         int i, namelen;
 419
 420         class = data->class;
 421         stats = &data->stats;
 422
 423         snprintf(name, 38, "%s", class->name);
 424         namelen = strlen(name);
 425
 426         if (stats->write_holdtime.nr) {
 427                 if (stats->read_holdtime.nr)
 428                         seq_printf(m, "%38s-W:", name);
 429                 else
 430                         seq_printf(m, "%40s:", name);
 431
 432                 seq_lock_time(m, &stats->write_waittime);
 433                 seq_puts(m, " ");
 434                 seq_lock_time(m, &stats->write_holdtime);
 435                 seq_puts(m, "\n");
 436         }
 437
 438         if (stats->read_holdtime.nr) {
 439                 seq_printf(m, "%38s-R:", name);
 440                 seq_lock_time(m, &stats->read_waittime);
 441                 seq_puts(m, " ");
 442                 seq_lock_time(m, &stats->read_holdtime);
 443                 seq_puts(m, "\n");
 444         }
 445
 446         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
 447                 return;
 448
 449         if (stats->read_holdtime.nr)
 450                 namelen += 2;
 451
 452         for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
 453                 char sym[KSYM_SYMBOL_LEN];
 454                 char ip[32];
 455
 456                 if (class->contention_point[i] == 0)
 457                         break;
 458
 459                 if (!i)
 460                         seq_line(m, '-', 40-namelen, namelen);
 461
 462                 sprint_symbol(sym, class->contention_point[i]);
 463                 snprintf(ip, sizeof(ip), "[<%p>]",
 464                                 (void *)class->contention_point[i]);
 465                 seq_printf(m, "%40s %14lu %29s %s\n", name,
 466                                 stats->contention_point[i],
 467                                 ip, sym);
 468         }
 469         if (i) {
 470                 seq_puts(m, "\n");
 471                 seq_line(m, '.', 0, 40 + 1 + 8 * (14 + 1));
 472                 seq_puts(m, "\n");
 473         }
 474 }
 475
 476 static void seq_header(struct seq_file *m)
 477 {
 478         seq_printf(m, "lock_stat version 0.1\n");
 479         seq_line(m, '-', 0, 40 + 1 + 8 * (14 + 1));
 480         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s\n",
 481                         "class name",
 482                         "contentions",
 483                         "waittime-min",
 484                         "waittime-max",
 485                         "waittime-total",
 486                         "acquisitions",
 487                         "holdtime-min",
 488                         "holdtime-max",
 489                         "holdtime-total");
 490         seq_line(m, '-', 0, 40 + 1 + 8 * (14 + 1));
 491         seq_printf(m, "\n");
 492 }
 493
 494 static void *ls_start(struct seq_file *m, loff_t *pos)
 495 {
 496         struct lock_stat_seq *data = m->private;
 497
 498         if (data->iter == data->stats)
 499                 seq_header(m);
 500
 501         return data->iter;
 502 }
 503
 504 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
 505 {
 506         struct lock_stat_seq *data = m->private;
 507
 508         (*pos)++;
 509
 510         data->iter = v;
 511         data->iter++;
 512         if (data->iter == data->iter_end)
 513                 data->iter = NULL;
 514
 515         return data->iter;
 516 }
 517
 518 static void ls_stop(struct seq_file *m, void *v)
 519 {
 520 }
 521
 522 static int ls_show(struct seq_file *m, void *v)
 523 {
 524         struct lock_stat_seq *data = m->private;
 525
 526         seq_stats(m, data->iter);
 527         return 0;
 528 }
 529
 530 static struct seq_operations lockstat_ops = {
 531         .start  = ls_start,
 532         .next   = ls_next,
 533         .stop   = ls_stop,
 534         .show   = ls_show,
 535 };
 536
 537 static int lock_stat_open(struct inode *inode, struct file *file)
 538 {
 539         int res;
 540         struct lock_class *class;
 541         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
 542
 543         if (!data)
 544                 return -ENOMEM;
 545
 546         res = seq_open(file, &lockstat_ops);
 547         if (!res) {
 548                 struct lock_stat_data *iter = data->stats;
 549                 struct seq_file *m = file->private_data;
 550
 551                 data->iter = iter;
 552                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
 553                         iter->class = class;
 554                         iter->stats = lock_stats(class);
 555                         iter++;
 556                 }
 557                 data->iter_end = iter;
 558
 559                 sort(data->stats, data->iter_end - data->iter,
 560                                 sizeof(struct lock_stat_data),
 561                                 lock_stat_cmp, NULL);
 562
 563                 m->private = data;
 564         } else
 565                 vfree(data);
 566
 567         return res;
 568 }
 569
 570 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
 571                                size_t count, loff_t *ppos)
 572 {
 573         struct lock_class *class;
 574         char c;
 575
 576         if (count) {
 577                 if (get_user(c, buf))
 578                         return -EFAULT;
 579
 580                 if (c != '0')
 581                         return count;
 582
 583                 list_for_each_entry(class, &all_lock_classes, lock_entry)
 584                         clear_lock_stats(class);
 585         }
 586         return count;
 587 }
 588
 589 static int lock_stat_release(struct inode *inode, struct file *file)
 590 {
 591         struct seq_file *seq = file->private_data;
 592
 593         vfree(seq->private);
 594         seq->private = NULL;
 595         return seq_release(inode, file);
 596 }
 597
 598 static const struct file_operations proc_lock_stat_operations = {
 599         .open           = lock_stat_open,
 600         .write          = lock_stat_write,
 601         .read           = seq_read,
 602         .llseek         = seq_lseek,
 603         .release        = lock_stat_release,
 604 };
 605 #endif /* CONFIG_LOCK_STAT */
 606
 607 static int __init lockdep_proc_init(void)
 608 {
 609         struct proc_dir_entry *entry;
 610
 611         entry = create_proc_entry("lockdep", S_IRUSR, NULL);
 612         if (entry)
 613                 entry->proc_fops = &proc_lockdep_operations;
 614
 615         entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
 616         if (entry)
 617                 entry->proc_fops = &proc_lockdep_stats_operations;
 618
 619 #ifdef CONFIG_LOCK_STAT
 620         entry = create_proc_entry("lock_stat", S_IRUSR, NULL);
 621         if (entry)
 622                 entry->proc_fops = &proc_lock_stat_operations;
 623 #endif
 624
 625         return 0;
 626 }
 627
 628 __initcall(lockdep_proc_init);
 629