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