linux/kernel/locking/lockdep_proc.c
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   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
  27static 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
  32static void *l_start(struct seq_file *m, loff_t *pos)
  33{
  34        return seq_list_start_head(&all_lock_classes, *pos);
  35}
  36
  37static void l_stop(struct seq_file *m, void *v)
  38{
  39}
  40
  41static 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
  58static 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
  99static 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
 107static 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
 118static 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
 124static void lc_stop(struct seq_file *m, void *v)
 125{
 126}
 127
 128static 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
 164static const struct seq_operations lockdep_chains_ops = {
 165        .start  = lc_start,
 166        .next   = lc_next,
 167        .stop   = lc_stop,
 168        .show   = lc_show,
 169};
 170#endif /* CONFIG_PROVE_LOCKING */
 171
 172static 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
 210static 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
 369struct lock_stat_data {
 370        struct lock_class *class;
 371        struct lock_class_stats stats;
 372};
 373
 374struct 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 */
 382static 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
 393static 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
 404static 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
 414static 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
 422static 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
 431static 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
 543static 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
 570static 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
 585static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
 586{
 587        (*pos)++;
 588        return ls_start(m, pos);
 589}
 590
 591static void ls_stop(struct seq_file *m, void *v)
 592{
 593}
 594
 595static 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
 605static const struct seq_operations lockstat_ops = {
 606        .start  = ls_start,
 607        .next   = ls_next,
 608        .stop   = ls_stop,
 609        .show   = ls_show,
 610};
 611
 612static 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
 644static 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
 663static 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
 671static 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
 680static 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
 696
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