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