Linux 6.7-rc7
[linux-modified.git] / 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 /*
28  * Since iteration of lock_classes is done without holding the lockdep lock,
29  * it is not safe to iterate all_lock_classes list directly as the iteration
30  * may branch off to free_lock_classes or the zapped list. Iteration is done
31  * directly on the lock_classes array by checking the lock_classes_in_use
32  * bitmap and max_lock_class_idx.
33  */
34 #define iterate_lock_classes(idx, class)                                \
35         for (idx = 0, class = lock_classes; idx <= max_lock_class_idx;  \
36              idx++, class++)
37
38 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
39 {
40         struct lock_class *class = v;
41
42         ++class;
43         *pos = class - lock_classes;
44         return (*pos > max_lock_class_idx) ? NULL : class;
45 }
46
47 static void *l_start(struct seq_file *m, loff_t *pos)
48 {
49         unsigned long idx = *pos;
50
51         if (idx > max_lock_class_idx)
52                 return NULL;
53         return lock_classes + idx;
54 }
55
56 static void l_stop(struct seq_file *m, void *v)
57 {
58 }
59
60 static void print_name(struct seq_file *m, struct lock_class *class)
61 {
62         char str[KSYM_NAME_LEN];
63         const char *name = class->name;
64
65         if (!name) {
66                 name = __get_key_name(class->key, str);
67                 seq_printf(m, "%s", name);
68         } else{
69                 seq_printf(m, "%s", name);
70                 if (class->name_version > 1)
71                         seq_printf(m, "#%d", class->name_version);
72                 if (class->subclass)
73                         seq_printf(m, "/%d", class->subclass);
74         }
75 }
76
77 static int l_show(struct seq_file *m, void *v)
78 {
79         struct lock_class *class = v;
80         struct lock_list *entry;
81         char usage[LOCK_USAGE_CHARS];
82         int idx = class - lock_classes;
83
84         if (v == lock_classes)
85                 seq_printf(m, "all lock classes:\n");
86
87         if (!test_bit(idx, lock_classes_in_use))
88                 return 0;
89
90         seq_printf(m, "%p", class->key);
91 #ifdef CONFIG_DEBUG_LOCKDEP
92         seq_printf(m, " OPS:%8ld", debug_class_ops_read(class));
93 #endif
94         if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
95                 seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
96                 seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
97
98                 get_usage_chars(class, usage);
99                 seq_printf(m, " %s", usage);
100         }
101
102         seq_printf(m, ": ");
103         print_name(m, class);
104         seq_puts(m, "\n");
105
106         if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
107                 list_for_each_entry(entry, &class->locks_after, entry) {
108                         if (entry->distance == 1) {
109                                 seq_printf(m, " -> [%p] ", entry->class->key);
110                                 print_name(m, entry->class);
111                                 seq_puts(m, "\n");
112                         }
113                 }
114                 seq_puts(m, "\n");
115         }
116
117         return 0;
118 }
119
120 static const struct seq_operations lockdep_ops = {
121         .start  = l_start,
122         .next   = l_next,
123         .stop   = l_stop,
124         .show   = l_show,
125 };
126
127 #ifdef CONFIG_PROVE_LOCKING
128 static void *lc_start(struct seq_file *m, loff_t *pos)
129 {
130         if (*pos < 0)
131                 return NULL;
132
133         if (*pos == 0)
134                 return SEQ_START_TOKEN;
135
136         return lock_chains + (*pos - 1);
137 }
138
139 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
140 {
141         *pos = lockdep_next_lockchain(*pos - 1) + 1;
142         return lc_start(m, pos);
143 }
144
145 static void lc_stop(struct seq_file *m, void *v)
146 {
147 }
148
149 static int lc_show(struct seq_file *m, void *v)
150 {
151         struct lock_chain *chain = v;
152         struct lock_class *class;
153         int i;
154         static const char * const irq_strs[] = {
155                 [0]                          = "0",
156                 [LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq",
157                 [LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq",
158                 [LOCK_CHAIN_SOFTIRQ_CONTEXT|
159                  LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq",
160         };
161
162         if (v == SEQ_START_TOKEN) {
163                 if (!nr_free_chain_hlocks)
164                         seq_printf(m, "(buggered) ");
165                 seq_printf(m, "all lock chains:\n");
166                 return 0;
167         }
168
169         seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]);
170
171         for (i = 0; i < chain->depth; i++) {
172                 class = lock_chain_get_class(chain, i);
173                 if (!class->key)
174                         continue;
175
176                 seq_printf(m, "[%p] ", class->key);
177                 print_name(m, class);
178                 seq_puts(m, "\n");
179         }
180         seq_puts(m, "\n");
181
182         return 0;
183 }
184
185 static const struct seq_operations lockdep_chains_ops = {
186         .start  = lc_start,
187         .next   = lc_next,
188         .stop   = lc_stop,
189         .show   = lc_show,
190 };
191 #endif /* CONFIG_PROVE_LOCKING */
192
193 static void lockdep_stats_debug_show(struct seq_file *m)
194 {
195 #ifdef CONFIG_DEBUG_LOCKDEP
196         unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
197                            hi2 = debug_atomic_read(hardirqs_off_events),
198                            hr1 = debug_atomic_read(redundant_hardirqs_on),
199                            hr2 = debug_atomic_read(redundant_hardirqs_off),
200                            si1 = debug_atomic_read(softirqs_on_events),
201                            si2 = debug_atomic_read(softirqs_off_events),
202                            sr1 = debug_atomic_read(redundant_softirqs_on),
203                            sr2 = debug_atomic_read(redundant_softirqs_off);
204
205         seq_printf(m, " chain lookup misses:           %11llu\n",
206                 debug_atomic_read(chain_lookup_misses));
207         seq_printf(m, " chain lookup hits:             %11llu\n",
208                 debug_atomic_read(chain_lookup_hits));
209         seq_printf(m, " cyclic checks:                 %11llu\n",
210                 debug_atomic_read(nr_cyclic_checks));
211         seq_printf(m, " redundant checks:              %11llu\n",
212                 debug_atomic_read(nr_redundant_checks));
213         seq_printf(m, " redundant links:               %11llu\n",
214                 debug_atomic_read(nr_redundant));
215         seq_printf(m, " find-mask forwards checks:     %11llu\n",
216                 debug_atomic_read(nr_find_usage_forwards_checks));
217         seq_printf(m, " find-mask backwards checks:    %11llu\n",
218                 debug_atomic_read(nr_find_usage_backwards_checks));
219
220         seq_printf(m, " hardirq on events:             %11llu\n", hi1);
221         seq_printf(m, " hardirq off events:            %11llu\n", hi2);
222         seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
223         seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
224         seq_printf(m, " softirq on events:             %11llu\n", si1);
225         seq_printf(m, " softirq off events:            %11llu\n", si2);
226         seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
227         seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
228 #endif
229 }
230
231 static int lockdep_stats_show(struct seq_file *m, void *v)
232 {
233         unsigned long nr_unused = 0, nr_uncategorized = 0,
234                       nr_irq_safe = 0, nr_irq_unsafe = 0,
235                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
236                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
237                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
238                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
239                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
240                       sum_forward_deps = 0;
241
242 #ifdef CONFIG_PROVE_LOCKING
243         struct lock_class *class;
244         unsigned long idx;
245
246         iterate_lock_classes(idx, class) {
247                 if (!test_bit(idx, lock_classes_in_use))
248                         continue;
249
250                 if (class->usage_mask == 0)
251                         nr_unused++;
252                 if (class->usage_mask == LOCKF_USED)
253                         nr_uncategorized++;
254                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
255                         nr_irq_safe++;
256                 if (class->usage_mask & LOCKF_ENABLED_IRQ)
257                         nr_irq_unsafe++;
258                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
259                         nr_softirq_safe++;
260                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
261                         nr_softirq_unsafe++;
262                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
263                         nr_hardirq_safe++;
264                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
265                         nr_hardirq_unsafe++;
266                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
267                         nr_irq_read_safe++;
268                 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
269                         nr_irq_read_unsafe++;
270                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
271                         nr_softirq_read_safe++;
272                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
273                         nr_softirq_read_unsafe++;
274                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
275                         nr_hardirq_read_safe++;
276                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
277                         nr_hardirq_read_unsafe++;
278
279                 sum_forward_deps += lockdep_count_forward_deps(class);
280         }
281
282 #ifdef CONFIG_DEBUG_LOCKDEP
283         DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
284 #endif
285
286 #endif
287         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
288                         nr_lock_classes, MAX_LOCKDEP_KEYS);
289         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
290                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
291         seq_printf(m, " indirect dependencies:         %11lu\n",
292                         sum_forward_deps);
293
294         /*
295          * Total number of dependencies:
296          *
297          * All irq-safe locks may nest inside irq-unsafe locks,
298          * plus all the other known dependencies:
299          */
300         seq_printf(m, " all direct dependencies:       %11lu\n",
301                         nr_irq_unsafe * nr_irq_safe +
302                         nr_hardirq_unsafe * nr_hardirq_safe +
303                         nr_list_entries);
304
305 #ifdef CONFIG_PROVE_LOCKING
306         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
307                         lock_chain_count(), MAX_LOCKDEP_CHAINS);
308         seq_printf(m, " dependency chain hlocks used:  %11lu [max: %lu]\n",
309                         MAX_LOCKDEP_CHAIN_HLOCKS -
310                         (nr_free_chain_hlocks + nr_lost_chain_hlocks),
311                         MAX_LOCKDEP_CHAIN_HLOCKS);
312         seq_printf(m, " dependency chain hlocks lost:  %11u\n",
313                         nr_lost_chain_hlocks);
314 #endif
315
316 #ifdef CONFIG_TRACE_IRQFLAGS
317         seq_printf(m, " in-hardirq chains:             %11u\n",
318                         nr_hardirq_chains);
319         seq_printf(m, " in-softirq chains:             %11u\n",
320                         nr_softirq_chains);
321 #endif
322         seq_printf(m, " in-process chains:             %11u\n",
323                         nr_process_chains);
324         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
325                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
326 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
327         seq_printf(m, " number of stack traces:        %11llu\n",
328                    lockdep_stack_trace_count());
329         seq_printf(m, " number of stack hash chains:   %11llu\n",
330                    lockdep_stack_hash_count());
331 #endif
332         seq_printf(m, " combined max dependencies:     %11u\n",
333                         (nr_hardirq_chains + 1) *
334                         (nr_softirq_chains + 1) *
335                         (nr_process_chains + 1)
336         );
337         seq_printf(m, " hardirq-safe locks:            %11lu\n",
338                         nr_hardirq_safe);
339         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
340                         nr_hardirq_unsafe);
341         seq_printf(m, " softirq-safe locks:            %11lu\n",
342                         nr_softirq_safe);
343         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
344                         nr_softirq_unsafe);
345         seq_printf(m, " irq-safe locks:                %11lu\n",
346                         nr_irq_safe);
347         seq_printf(m, " irq-unsafe locks:              %11lu\n",
348                         nr_irq_unsafe);
349
350         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
351                         nr_hardirq_read_safe);
352         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
353                         nr_hardirq_read_unsafe);
354         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
355                         nr_softirq_read_safe);
356         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
357                         nr_softirq_read_unsafe);
358         seq_printf(m, " irq-read-safe locks:           %11lu\n",
359                         nr_irq_read_safe);
360         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
361                         nr_irq_read_unsafe);
362
363         seq_printf(m, " uncategorized locks:           %11lu\n",
364                         nr_uncategorized);
365         seq_printf(m, " unused locks:                  %11lu\n",
366                         nr_unused);
367         seq_printf(m, " max locking depth:             %11u\n",
368                         max_lockdep_depth);
369 #ifdef CONFIG_PROVE_LOCKING
370         seq_printf(m, " max bfs queue depth:           %11u\n",
371                         max_bfs_queue_depth);
372 #endif
373         seq_printf(m, " max lock class index:          %11lu\n",
374                         max_lock_class_idx);
375         lockdep_stats_debug_show(m);
376         seq_printf(m, " debug_locks:                   %11u\n",
377                         debug_locks);
378
379         /*
380          * Zapped classes and lockdep data buffers reuse statistics.
381          */
382         seq_puts(m, "\n");
383         seq_printf(m, " zapped classes:                %11lu\n",
384                         nr_zapped_classes);
385 #ifdef CONFIG_PROVE_LOCKING
386         seq_printf(m, " zapped lock chains:            %11lu\n",
387                         nr_zapped_lock_chains);
388         seq_printf(m, " large chain blocks:            %11u\n",
389                         nr_large_chain_blocks);
390 #endif
391         return 0;
392 }
393
394 #ifdef CONFIG_LOCK_STAT
395
396 struct lock_stat_data {
397         struct lock_class *class;
398         struct lock_class_stats stats;
399 };
400
401 struct lock_stat_seq {
402         struct lock_stat_data *iter_end;
403         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
404 };
405
406 /*
407  * sort on absolute number of contentions
408  */
409 static int lock_stat_cmp(const void *l, const void *r)
410 {
411         const struct lock_stat_data *dl = l, *dr = r;
412         unsigned long nl, nr;
413
414         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
415         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
416
417         return nr - nl;
418 }
419
420 static void seq_line(struct seq_file *m, char c, int offset, int length)
421 {
422         int i;
423
424         for (i = 0; i < offset; i++)
425                 seq_puts(m, " ");
426         for (i = 0; i < length; i++)
427                 seq_printf(m, "%c", c);
428         seq_puts(m, "\n");
429 }
430
431 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
432 {
433         s64 div;
434         s32 rem;
435
436         nr += 5; /* for display rounding */
437         div = div_s64_rem(nr, 1000, &rem);
438         snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
439 }
440
441 static void seq_time(struct seq_file *m, s64 time)
442 {
443         char num[22];
444
445         snprint_time(num, sizeof(num), time);
446         seq_printf(m, " %14s", num);
447 }
448
449 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
450 {
451         seq_printf(m, "%14lu", lt->nr);
452         seq_time(m, lt->min);
453         seq_time(m, lt->max);
454         seq_time(m, lt->total);
455         seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0);
456 }
457
458 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
459 {
460         const struct lockdep_subclass_key *ckey;
461         struct lock_class_stats *stats;
462         struct lock_class *class;
463         const char *cname;
464         int i, namelen;
465         char name[39];
466
467         class = data->class;
468         stats = &data->stats;
469
470         namelen = 38;
471         if (class->name_version > 1)
472                 namelen -= 2; /* XXX truncates versions > 9 */
473         if (class->subclass)
474                 namelen -= 2;
475
476         rcu_read_lock_sched();
477         cname = rcu_dereference_sched(class->name);
478         ckey  = rcu_dereference_sched(class->key);
479
480         if (!cname && !ckey) {
481                 rcu_read_unlock_sched();
482                 return;
483
484         } else if (!cname) {
485                 char str[KSYM_NAME_LEN];
486                 const char *key_name;
487
488                 key_name = __get_key_name(ckey, str);
489                 snprintf(name, namelen, "%s", key_name);
490         } else {
491                 snprintf(name, namelen, "%s", cname);
492         }
493         rcu_read_unlock_sched();
494
495         namelen = strlen(name);
496         if (class->name_version > 1) {
497                 snprintf(name+namelen, 3, "#%d", class->name_version);
498                 namelen += 2;
499         }
500         if (class->subclass) {
501                 snprintf(name+namelen, 3, "/%d", class->subclass);
502                 namelen += 2;
503         }
504
505         if (stats->write_holdtime.nr) {
506                 if (stats->read_holdtime.nr)
507                         seq_printf(m, "%38s-W:", name);
508                 else
509                         seq_printf(m, "%40s:", name);
510
511                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
512                 seq_lock_time(m, &stats->write_waittime);
513                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
514                 seq_lock_time(m, &stats->write_holdtime);
515                 seq_puts(m, "\n");
516         }
517
518         if (stats->read_holdtime.nr) {
519                 seq_printf(m, "%38s-R:", name);
520                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
521                 seq_lock_time(m, &stats->read_waittime);
522                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
523                 seq_lock_time(m, &stats->read_holdtime);
524                 seq_puts(m, "\n");
525         }
526
527         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
528                 return;
529
530         if (stats->read_holdtime.nr)
531                 namelen += 2;
532
533         for (i = 0; i < LOCKSTAT_POINTS; i++) {
534                 char ip[32];
535
536                 if (class->contention_point[i] == 0)
537                         break;
538
539                 if (!i)
540                         seq_line(m, '-', 40-namelen, namelen);
541
542                 snprintf(ip, sizeof(ip), "[<%p>]",
543                                 (void *)class->contention_point[i]);
544                 seq_printf(m, "%40s %14lu %29s %pS\n",
545                            name, stats->contention_point[i],
546                            ip, (void *)class->contention_point[i]);
547         }
548         for (i = 0; i < LOCKSTAT_POINTS; i++) {
549                 char ip[32];
550
551                 if (class->contending_point[i] == 0)
552                         break;
553
554                 if (!i)
555                         seq_line(m, '-', 40-namelen, namelen);
556
557                 snprintf(ip, sizeof(ip), "[<%p>]",
558                                 (void *)class->contending_point[i]);
559                 seq_printf(m, "%40s %14lu %29s %pS\n",
560                            name, stats->contending_point[i],
561                            ip, (void *)class->contending_point[i]);
562         }
563         if (i) {
564                 seq_puts(m, "\n");
565                 seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
566                 seq_puts(m, "\n");
567         }
568 }
569
570 static void seq_header(struct seq_file *m)
571 {
572         seq_puts(m, "lock_stat version 0.4\n");
573
574         if (unlikely(!debug_locks))
575                 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
576
577         seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
578         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
579                         "%14s %14s\n",
580                         "class name",
581                         "con-bounces",
582                         "contentions",
583                         "waittime-min",
584                         "waittime-max",
585                         "waittime-total",
586                         "waittime-avg",
587                         "acq-bounces",
588                         "acquisitions",
589                         "holdtime-min",
590                         "holdtime-max",
591                         "holdtime-total",
592                         "holdtime-avg");
593         seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
594         seq_printf(m, "\n");
595 }
596
597 static void *ls_start(struct seq_file *m, loff_t *pos)
598 {
599         struct lock_stat_seq *data = m->private;
600         struct lock_stat_data *iter;
601
602         if (*pos == 0)
603                 return SEQ_START_TOKEN;
604
605         iter = data->stats + (*pos - 1);
606         if (iter >= data->iter_end)
607                 iter = NULL;
608
609         return iter;
610 }
611
612 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
613 {
614         (*pos)++;
615         return ls_start(m, pos);
616 }
617
618 static void ls_stop(struct seq_file *m, void *v)
619 {
620 }
621
622 static int ls_show(struct seq_file *m, void *v)
623 {
624         if (v == SEQ_START_TOKEN)
625                 seq_header(m);
626         else
627                 seq_stats(m, v);
628
629         return 0;
630 }
631
632 static const struct seq_operations lockstat_ops = {
633         .start  = ls_start,
634         .next   = ls_next,
635         .stop   = ls_stop,
636         .show   = ls_show,
637 };
638
639 static int lock_stat_open(struct inode *inode, struct file *file)
640 {
641         int res;
642         struct lock_class *class;
643         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
644
645         if (!data)
646                 return -ENOMEM;
647
648         res = seq_open(file, &lockstat_ops);
649         if (!res) {
650                 struct lock_stat_data *iter = data->stats;
651                 struct seq_file *m = file->private_data;
652                 unsigned long idx;
653
654                 iterate_lock_classes(idx, class) {
655                         if (!test_bit(idx, lock_classes_in_use))
656                                 continue;
657                         iter->class = class;
658                         iter->stats = lock_stats(class);
659                         iter++;
660                 }
661
662                 data->iter_end = iter;
663
664                 sort(data->stats, data->iter_end - data->stats,
665                                 sizeof(struct lock_stat_data),
666                                 lock_stat_cmp, NULL);
667
668                 m->private = data;
669         } else
670                 vfree(data);
671
672         return res;
673 }
674
675 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
676                                size_t count, loff_t *ppos)
677 {
678         struct lock_class *class;
679         unsigned long idx;
680         char c;
681
682         if (count) {
683                 if (get_user(c, buf))
684                         return -EFAULT;
685
686                 if (c != '0')
687                         return count;
688
689                 iterate_lock_classes(idx, class) {
690                         if (!test_bit(idx, lock_classes_in_use))
691                                 continue;
692                         clear_lock_stats(class);
693                 }
694         }
695         return count;
696 }
697
698 static int lock_stat_release(struct inode *inode, struct file *file)
699 {
700         struct seq_file *seq = file->private_data;
701
702         vfree(seq->private);
703         return seq_release(inode, file);
704 }
705
706 static const struct proc_ops lock_stat_proc_ops = {
707         .proc_open      = lock_stat_open,
708         .proc_write     = lock_stat_write,
709         .proc_read      = seq_read,
710         .proc_lseek     = seq_lseek,
711         .proc_release   = lock_stat_release,
712 };
713 #endif /* CONFIG_LOCK_STAT */
714
715 static int __init lockdep_proc_init(void)
716 {
717         proc_create_seq("lockdep", S_IRUSR, NULL, &lockdep_ops);
718 #ifdef CONFIG_PROVE_LOCKING
719         proc_create_seq("lockdep_chains", S_IRUSR, NULL, &lockdep_chains_ops);
720 #endif
721         proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show);
722 #ifdef CONFIG_LOCK_STAT
723         proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, &lock_stat_proc_ops);
724 #endif
725
726         return 0;
727 }
728
729 __initcall(lockdep_proc_init);
730