kernel/locking/lockdep_proc.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * kernel/lockdep_proc.c
   4  *
   5  * Runtime locking correctness validator
   6  *
   7  * Started by Ingo Molnar:
   8  *
   9  *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
  10  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
  11  *
  12  * Code for /proc/lockdep and /proc/lockdep_stats:
  13  *
  14  */
  15 #include <linux/export.h>
  16 #include <linux/proc_fs.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/kallsyms.h>
  19 #include <linux/debug_locks.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/sort.h>
  22 #include <linux/uaccess.h>
  23 #include <asm/div64.h>
  24
  25 #include "lockdep_internals.h"
  26
  27 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
  28 {
  29         return seq_list_next(v, &all_lock_classes, pos);
  30 }
  31
  32 static void *l_start(struct seq_file *m, loff_t *pos)
  33 {
  34         return seq_list_start_head(&all_lock_classes, *pos);
  35 }
  36
  37 static void l_stop(struct seq_file *m, void *v)
  38 {
  39 }
  40
  41 static void print_name(struct seq_file *m, struct lock_class *class)
  42 {
  43         char str[KSYM_NAME_LEN];
  44         const char *name = class->name;
  45
  46         if (!name) {
  47                 name = __get_key_name(class->key, str);
  48                 seq_printf(m, "%s", name);
  49         } else{
  50                 seq_printf(m, "%s", name);
  51                 if (class->name_version > 1)
  52                         seq_printf(m, "#%d", class->name_version);
  53                 if (class->subclass)
  54                         seq_printf(m, "/%d", class->subclass);
  55         }
  56 }
  57
  58 static int l_show(struct seq_file *m, void *v)
  59 {
  60         struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
  61         struct lock_list *entry;
  62         char usage[LOCK_USAGE_CHARS];
  63
  64         if (v == &all_lock_classes) {
  65                 seq_printf(m, "all lock classes:\n");
  66                 return 0;
  67         }
  68
  69         seq_printf(m, "%p", class->key);
  70 #ifdef CONFIG_DEBUG_LOCKDEP
  71         seq_printf(m, " OPS:%8ld", class->ops);
  72 #endif
  73 #ifdef CONFIG_PROVE_LOCKING
  74         seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
  75         seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
  76 #endif
  77
  78         get_usage_chars(class, usage);
  79         seq_printf(m, " %s", usage);
  80
  81         seq_printf(m, ": ");
  82         print_name(m, class);
  83         seq_puts(m, "\n");
  84
  85         list_for_each_entry(entry, &class->locks_after, entry) {
  86                 if (entry->distance == 1) {
  87                         seq_printf(m, " -> [%p] ", entry->class->key);
  88                         print_name(m, entry->class);
  89                         seq_puts(m, "\n");
  90                 }
  91         }
  92         seq_puts(m, "\n");
  93
  94         return 0;
  95 }
  96
  97 static const struct seq_operations lockdep_ops = {
  98         .start  = l_start,
  99         .next   = l_next,
 100         .stop   = l_stop,
 101         .show   = l_show,
 102 };
 103
 104 static int lockdep_open(struct inode *inode, struct file *file)
 105 {
 106         return seq_open(file, &lockdep_ops);
 107 }
 108
 109 static const struct file_operations proc_lockdep_operations = {
 110         .open           = lockdep_open,
 111         .read           = seq_read,
 112         .llseek         = seq_lseek,
 113         .release        = seq_release,
 114 };
 115
 116 #ifdef CONFIG_PROVE_LOCKING
 117 static void *lc_start(struct seq_file *m, loff_t *pos)
 118 {
 119         if (*pos == 0)
 120                 return SEQ_START_TOKEN;
 121
 122         if (*pos - 1 < nr_lock_chains)
 123                 return lock_chains + (*pos - 1);
 124
 125         return NULL;
 126 }
 127
 128 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
 129 {
 130         (*pos)++;
 131         return lc_start(m, pos);
 132 }
 133
 134 static void lc_stop(struct seq_file *m, void *v)
 135 {
 136 }
 137
 138 static int lc_show(struct seq_file *m, void *v)
 139 {
 140         struct lock_chain *chain = v;
 141         struct lock_class *class;
 142         int i;
 143
 144         if (v == SEQ_START_TOKEN) {
 145                 if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
 146                         seq_printf(m, "(buggered) ");
 147                 seq_printf(m, "all lock chains:\n");
 148                 return 0;
 149         }
 150
 151         seq_printf(m, "irq_context: %d\n", chain->irq_context);
 152
 153         for (i = 0; i < chain->depth; i++) {
 154                 class = lock_chain_get_class(chain, i);
 155                 if (!class->key)
 156                         continue;
 157
 158                 seq_printf(m, "[%p] ", class->key);
 159                 print_name(m, class);
 160                 seq_puts(m, "\n");
 161         }
 162         seq_puts(m, "\n");
 163
 164         return 0;
 165 }
 166
 167 static const struct seq_operations lockdep_chains_ops = {
 168         .start  = lc_start,
 169         .next   = lc_next,
 170         .stop   = lc_stop,
 171         .show   = lc_show,
 172 };
 173
 174 static int lockdep_chains_open(struct inode *inode, struct file *file)
 175 {
 176         return seq_open(file, &lockdep_chains_ops);
 177 }
 178
 179 static const struct file_operations proc_lockdep_chains_operations = {
 180         .open           = lockdep_chains_open,
 181         .read           = seq_read,
 182         .llseek         = seq_lseek,
 183         .release        = seq_release,
 184 };
 185 #endif /* CONFIG_PROVE_LOCKING */
 186
 187 static void lockdep_stats_debug_show(struct seq_file *m)
 188 {
 189 #ifdef CONFIG_DEBUG_LOCKDEP
 190         unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
 191                            hi2 = debug_atomic_read(hardirqs_off_events),
 192                            hr1 = debug_atomic_read(redundant_hardirqs_on),
 193                            hr2 = debug_atomic_read(redundant_hardirqs_off),
 194                            si1 = debug_atomic_read(softirqs_on_events),
 195                            si2 = debug_atomic_read(softirqs_off_events),
 196                            sr1 = debug_atomic_read(redundant_softirqs_on),
 197                            sr2 = debug_atomic_read(redundant_softirqs_off);
 198
 199         seq_printf(m, " chain lookup misses:           %11llu\n",
 200                 debug_atomic_read(chain_lookup_misses));
 201         seq_printf(m, " chain lookup hits:             %11llu\n",
 202                 debug_atomic_read(chain_lookup_hits));
 203         seq_printf(m, " cyclic checks:                 %11llu\n",
 204                 debug_atomic_read(nr_cyclic_checks));
 205         seq_printf(m, " redundant checks:              %11llu\n",
 206                 debug_atomic_read(nr_redundant_checks));
 207         seq_printf(m, " redundant links:               %11llu\n",
 208                 debug_atomic_read(nr_redundant));
 209         seq_printf(m, " find-mask forwards checks:     %11llu\n",
 210                 debug_atomic_read(nr_find_usage_forwards_checks));
 211         seq_printf(m, " find-mask backwards checks:    %11llu\n",
 212                 debug_atomic_read(nr_find_usage_backwards_checks));
 213
 214         seq_printf(m, " hardirq on events:             %11llu\n", hi1);
 215         seq_printf(m, " hardirq off events:            %11llu\n", hi2);
 216         seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
 217         seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
 218         seq_printf(m, " softirq on events:             %11llu\n", si1);
 219         seq_printf(m, " softirq off events:            %11llu\n", si2);
 220         seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
 221         seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
 222 #endif
 223 }
 224
 225 static int lockdep_stats_show(struct seq_file *m, void *v)
 226 {
 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 #ifdef CONFIG_PROVE_LOCKING
 237         struct lock_class *class;
 238
 239         list_for_each_entry(class, &all_lock_classes, lock_entry) {
 240
 241                 if (class->usage_mask == 0)
 242                         nr_unused++;
 243                 if (class->usage_mask == LOCKF_USED)
 244                         nr_uncategorized++;
 245                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
 246                         nr_irq_safe++;
 247                 if (class->usage_mask & LOCKF_ENABLED_IRQ)
 248                         nr_irq_unsafe++;
 249                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
 250                         nr_softirq_safe++;
 251                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
 252                         nr_softirq_unsafe++;
 253                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
 254                         nr_hardirq_safe++;
 255                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
 256                         nr_hardirq_unsafe++;
 257                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
 258                         nr_irq_read_safe++;
 259                 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
 260                         nr_irq_read_unsafe++;
 261                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
 262                         nr_softirq_read_safe++;
 263                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
 264                         nr_softirq_read_unsafe++;
 265                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
 266                         nr_hardirq_read_safe++;
 267                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
 268                         nr_hardirq_read_unsafe++;
 269
 270                 sum_forward_deps += lockdep_count_forward_deps(class);
 271         }
 272 #ifdef CONFIG_DEBUG_LOCKDEP
 273         DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
 274 #endif
 275
 276 #endif
 277         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
 278                         nr_lock_classes, MAX_LOCKDEP_KEYS);
 279         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
 280                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
 281         seq_printf(m, " indirect dependencies:         %11lu\n",
 282                         sum_forward_deps);
 283
 284         /*
 285          * Total number of dependencies:
 286          *
 287          * All irq-safe locks may nest inside irq-unsafe locks,
 288          * plus all the other known dependencies:
 289          */
 290         seq_printf(m, " all direct dependencies:       %11lu\n",
 291                         nr_irq_unsafe * nr_irq_safe +
 292                         nr_hardirq_unsafe * nr_hardirq_safe +
 293                         nr_list_entries);
 294
 295 #ifdef CONFIG_PROVE_LOCKING
 296         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
 297                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
 298         seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
 299                         nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
 300 #endif
 301
 302 #ifdef CONFIG_TRACE_IRQFLAGS
 303         seq_printf(m, " in-hardirq chains:             %11u\n",
 304                         nr_hardirq_chains);
 305         seq_printf(m, " in-softirq chains:             %11u\n",
 306                         nr_softirq_chains);
 307 #endif
 308         seq_printf(m, " in-process chains:             %11u\n",
 309                         nr_process_chains);
 310         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
 311                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
 312         seq_printf(m, " combined max dependencies:     %11u\n",
 313                         (nr_hardirq_chains + 1) *
 314                         (nr_softirq_chains + 1) *
 315                         (nr_process_chains + 1)
 316         );
 317         seq_printf(m, " hardirq-safe locks:            %11lu\n",
 318                         nr_hardirq_safe);
 319         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
 320                         nr_hardirq_unsafe);
 321         seq_printf(m, " softirq-safe locks:            %11lu\n",
 322                         nr_softirq_safe);
 323         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
 324                         nr_softirq_unsafe);
 325         seq_printf(m, " irq-safe locks:                %11lu\n",
 326                         nr_irq_safe);
 327         seq_printf(m, " irq-unsafe locks:              %11lu\n",
 328                         nr_irq_unsafe);
 329
 330         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
 331                         nr_hardirq_read_safe);
 332         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
 333                         nr_hardirq_read_unsafe);
 334         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
 335                         nr_softirq_read_safe);
 336         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
 337                         nr_softirq_read_unsafe);
 338         seq_printf(m, " irq-read-safe locks:           %11lu\n",
 339                         nr_irq_read_safe);
 340         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
 341                         nr_irq_read_unsafe);
 342
 343         seq_printf(m, " uncategorized locks:           %11lu\n",
 344                         nr_uncategorized);
 345         seq_printf(m, " unused locks:                  %11lu\n",
 346                         nr_unused);
 347         seq_printf(m, " max locking depth:             %11u\n",
 348                         max_lockdep_depth);
 349 #ifdef CONFIG_PROVE_LOCKING
 350         seq_printf(m, " max bfs queue depth:           %11u\n",
 351                         max_bfs_queue_depth);
 352 #endif
 353         lockdep_stats_debug_show(m);
 354         seq_printf(m, " debug_locks:                   %11u\n",
 355                         debug_locks);
 356
 357         return 0;
 358 }
 359
 360 static int lockdep_stats_open(struct inode *inode, struct file *file)
 361 {
 362         return single_open(file, lockdep_stats_show, NULL);
 363 }
 364
 365 static const struct file_operations proc_lockdep_stats_operations = {
 366         .open           = lockdep_stats_open,
 367         .read           = seq_read,
 368         .llseek         = seq_lseek,
 369         .release        = single_release,
 370 };
 371
 372 #ifdef CONFIG_LOCK_STAT
 373
 374 struct lock_stat_data {
 375         struct lock_class *class;
 376         struct lock_class_stats stats;
 377 };
 378
 379 struct lock_stat_seq {
 380         struct lock_stat_data *iter_end;
 381         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
 382 };
 383
 384 /*
 385  * sort on absolute number of contentions
 386  */
 387 static int lock_stat_cmp(const void *l, const void *r)
 388 {
 389         const struct lock_stat_data *dl = l, *dr = r;
 390         unsigned long nl, nr;
 391
 392         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
 393         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
 394
 395         return nr - nl;
 396 }
 397
 398 static void seq_line(struct seq_file *m, char c, int offset, int length)
 399 {
 400         int i;
 401
 402         for (i = 0; i < offset; i++)
 403                 seq_puts(m, " ");
 404         for (i = 0; i < length; i++)
 405                 seq_printf(m, "%c", c);
 406         seq_puts(m, "\n");
 407 }
 408
 409 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
 410 {
 411         s64 div;
 412         s32 rem;
 413
 414         nr += 5; /* for display rounding */
 415         div = div_s64_rem(nr, 1000, &rem);
 416         snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
 417 }
 418
 419 static void seq_time(struct seq_file *m, s64 time)
 420 {
 421         char num[15];
 422
 423         snprint_time(num, sizeof(num), time);
 424         seq_printf(m, " %14s", num);
 425 }
 426
 427 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
 428 {
 429         seq_printf(m, "%14lu", lt->nr);
 430         seq_time(m, lt->min);
 431         seq_time(m, lt->max);
 432         seq_time(m, lt->total);
 433         seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0);
 434 }
 435
 436 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
 437 {
 438         struct lockdep_subclass_key *ckey;
 439         struct lock_class_stats *stats;
 440         struct lock_class *class;
 441         const char *cname;
 442         int i, namelen;
 443         char name[39];
 444
 445         class = data->class;
 446         stats = &data->stats;
 447
 448         namelen = 38;
 449         if (class->name_version > 1)
 450                 namelen -= 2; /* XXX truncates versions > 9 */
 451         if (class->subclass)
 452                 namelen -= 2;
 453
 454         rcu_read_lock_sched();
 455         cname = rcu_dereference_sched(class->name);
 456         ckey  = rcu_dereference_sched(class->key);
 457
 458         if (!cname && !ckey) {
 459                 rcu_read_unlock_sched();
 460                 return;
 461
 462         } else if (!cname) {
 463                 char str[KSYM_NAME_LEN];
 464                 const char *key_name;
 465
 466                 key_name = __get_key_name(ckey, str);
 467                 snprintf(name, namelen, "%s", key_name);
 468         } else {
 469                 snprintf(name, namelen, "%s", cname);
 470         }
 471         rcu_read_unlock_sched();
 472
 473         namelen = strlen(name);
 474         if (class->name_version > 1) {
 475                 snprintf(name+namelen, 3, "#%d", class->name_version);
 476                 namelen += 2;
 477         }
 478         if (class->subclass) {
 479                 snprintf(name+namelen, 3, "/%d", class->subclass);
 480                 namelen += 2;
 481         }
 482
 483         if (stats->write_holdtime.nr) {
 484                 if (stats->read_holdtime.nr)
 485                         seq_printf(m, "%38s-W:", name);
 486                 else
 487                         seq_printf(m, "%40s:", name);
 488
 489                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
 490                 seq_lock_time(m, &stats->write_waittime);
 491                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
 492                 seq_lock_time(m, &stats->write_holdtime);
 493                 seq_puts(m, "\n");
 494         }
 495
 496         if (stats->read_holdtime.nr) {
 497                 seq_printf(m, "%38s-R:", name);
 498                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
 499                 seq_lock_time(m, &stats->read_waittime);
 500                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
 501                 seq_lock_time(m, &stats->read_holdtime);
 502                 seq_puts(m, "\n");
 503         }
 504
 505         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
 506                 return;
 507
 508         if (stats->read_holdtime.nr)
 509                 namelen += 2;
 510
 511         for (i = 0; i < LOCKSTAT_POINTS; i++) {
 512                 char ip[32];
 513
 514                 if (class->contention_point[i] == 0)
 515                         break;
 516
 517                 if (!i)
 518                         seq_line(m, '-', 40-namelen, namelen);
 519
 520                 snprintf(ip, sizeof(ip), "[<%p>]",
 521                                 (void *)class->contention_point[i]);
 522                 seq_printf(m, "%40s %14lu %29s %pS\n",
 523                            name, stats->contention_point[i],
 524                            ip, (void *)class->contention_point[i]);
 525         }
 526         for (i = 0; i < LOCKSTAT_POINTS; i++) {
 527                 char ip[32];
 528
 529                 if (class->contending_point[i] == 0)
 530                         break;
 531
 532                 if (!i)
 533                         seq_line(m, '-', 40-namelen, namelen);
 534
 535                 snprintf(ip, sizeof(ip), "[<%p>]",
 536                                 (void *)class->contending_point[i]);
 537                 seq_printf(m, "%40s %14lu %29s %pS\n",
 538                            name, stats->contending_point[i],
 539                            ip, (void *)class->contending_point[i]);
 540         }
 541         if (i) {
 542                 seq_puts(m, "\n");
 543                 seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
 544                 seq_puts(m, "\n");
 545         }
 546 }
 547
 548 static void seq_header(struct seq_file *m)
 549 {
 550         seq_puts(m, "lock_stat version 0.4\n");
 551
 552         if (unlikely(!debug_locks))
 553                 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
 554
 555         seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
 556         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
 557                         "%14s %14s\n",
 558                         "class name",
 559                         "con-bounces",
 560                         "contentions",
 561                         "waittime-min",
 562                         "waittime-max",
 563                         "waittime-total",
 564                         "waittime-avg",
 565                         "acq-bounces",
 566                         "acquisitions",
 567                         "holdtime-min",
 568                         "holdtime-max",
 569                         "holdtime-total",
 570                         "holdtime-avg");
 571         seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
 572         seq_printf(m, "\n");
 573 }
 574
 575 static void *ls_start(struct seq_file *m, loff_t *pos)
 576 {
 577         struct lock_stat_seq *data = m->private;
 578         struct lock_stat_data *iter;
 579
 580         if (*pos == 0)
 581                 return SEQ_START_TOKEN;
 582
 583         iter = data->stats + (*pos - 1);
 584         if (iter >= data->iter_end)
 585                 iter = NULL;
 586
 587         return iter;
 588 }
 589
 590 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
 591 {
 592         (*pos)++;
 593         return ls_start(m, pos);
 594 }
 595
 596 static void ls_stop(struct seq_file *m, void *v)
 597 {
 598 }
 599
 600 static int ls_show(struct seq_file *m, void *v)
 601 {
 602         if (v == SEQ_START_TOKEN)
 603                 seq_header(m);
 604         else
 605                 seq_stats(m, v);
 606
 607         return 0;
 608 }
 609
 610 static const struct seq_operations lockstat_ops = {
 611         .start  = ls_start,
 612         .next   = ls_next,
 613         .stop   = ls_stop,
 614         .show   = ls_show,
 615 };
 616
 617 static int lock_stat_open(struct inode *inode, struct file *file)
 618 {
 619         int res;
 620         struct lock_class *class;
 621         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
 622
 623         if (!data)
 624                 return -ENOMEM;
 625
 626         res = seq_open(file, &lockstat_ops);
 627         if (!res) {
 628                 struct lock_stat_data *iter = data->stats;
 629                 struct seq_file *m = file->private_data;
 630
 631                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
 632                         iter->class = class;
 633                         iter->stats = lock_stats(class);
 634                         iter++;
 635                 }
 636                 data->iter_end = iter;
 637
 638                 sort(data->stats, data->iter_end - data->stats,
 639                                 sizeof(struct lock_stat_data),
 640                                 lock_stat_cmp, NULL);
 641
 642                 m->private = data;
 643         } else
 644                 vfree(data);
 645
 646         return res;
 647 }
 648
 649 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
 650                                size_t count, loff_t *ppos)
 651 {
 652         struct lock_class *class;
 653         char c;
 654
 655         if (count) {
 656                 if (get_user(c, buf))
 657                         return -EFAULT;
 658
 659                 if (c != '0')
 660                         return count;
 661
 662                 list_for_each_entry(class, &all_lock_classes, lock_entry)
 663                         clear_lock_stats(class);
 664         }
 665         return count;
 666 }
 667
 668 static int lock_stat_release(struct inode *inode, struct file *file)
 669 {
 670         struct seq_file *seq = file->private_data;
 671
 672         vfree(seq->private);
 673         return seq_release(inode, file);
 674 }
 675
 676 static const struct file_operations proc_lock_stat_operations = {
 677         .open           = lock_stat_open,
 678         .write          = lock_stat_write,
 679         .read           = seq_read,
 680         .llseek         = seq_lseek,
 681         .release        = lock_stat_release,
 682 };
 683 #endif /* CONFIG_LOCK_STAT */
 684
 685 static int __init lockdep_proc_init(void)
 686 {
 687         proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
 688 #ifdef CONFIG_PROVE_LOCKING
 689         proc_create("lockdep_chains", S_IRUSR, NULL,
 690                     &proc_lockdep_chains_operations);
 691 #endif
 692         proc_create("lockdep_stats", S_IRUSR, NULL,
 693                     &proc_lockdep_stats_operations);
 694
 695 #ifdef CONFIG_LOCK_STAT
 696         proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
 697                     &proc_lock_stat_operations);
 698 #endif
 699
 700         return 0;
 701 }
 702
 703 __initcall(lockdep_proc_init);
 704