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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", class->ops);
72#endif
73#ifdef CONFIG_PROVE_LOCKING
74 seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
75 seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
76#endif
77
78 get_usage_chars(class, usage);
79 seq_printf(m, " %s", usage);
80
81 seq_printf(m, ": ");
82 print_name(m, class);
83 seq_puts(m, "\n");
84
85 list_for_each_entry(entry, &class->locks_after, entry) {
86 if (entry->distance == 1) {
87 seq_printf(m, " -> [%p] ", entry->class->key);
88 print_name(m, entry->class);
89 seq_puts(m, "\n");
90 }
91 }
92 seq_puts(m, "\n");
93
94 return 0;
95}
96
97static const struct seq_operations lockdep_ops = {
98 .start = l_start,
99 .next = l_next,
100 .stop = l_stop,
101 .show = l_show,
102};
103
104static int lockdep_open(struct inode *inode, struct file *file)
105{
106 return seq_open(file, &lockdep_ops);
107}
108
109static const struct file_operations proc_lockdep_operations = {
110 .open = lockdep_open,
111 .read = seq_read,
112 .llseek = seq_lseek,
113 .release = seq_release,
114};
115
116#ifdef CONFIG_PROVE_LOCKING
117static void *lc_start(struct seq_file *m, loff_t *pos)
118{
119 if (*pos == 0)
120 return SEQ_START_TOKEN;
121
122 if (*pos - 1 < nr_lock_chains)
123 return lock_chains + (*pos - 1);
124
125 return NULL;
126}
127
128static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
129{
130 (*pos)++;
131 return lc_start(m, pos);
132}
133
134static void lc_stop(struct seq_file *m, void *v)
135{
136}
137
138static int lc_show(struct seq_file *m, void *v)
139{
140 struct lock_chain *chain = v;
141 struct lock_class *class;
142 int i;
143
144 if (v == SEQ_START_TOKEN) {
145 if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
146 seq_printf(m, "(buggered) ");
147 seq_printf(m, "all lock chains:\n");
148 return 0;
149 }
150
151 seq_printf(m, "irq_context: %d\n", chain->irq_context);
152
153 for (i = 0; i < chain->depth; i++) {
154 class = lock_chain_get_class(chain, i);
155 if (!class->key)
156 continue;
157
158 seq_printf(m, "[%p] ", class->key);
159 print_name(m, class);
160 seq_puts(m, "\n");
161 }
162 seq_puts(m, "\n");
163
164 return 0;
165}
166
167static const struct seq_operations lockdep_chains_ops = {
168 .start = lc_start,
169 .next = lc_next,
170 .stop = lc_stop,
171 .show = lc_show,
172};
173
174static int lockdep_chains_open(struct inode *inode, struct file *file)
175{
176 return seq_open(file, &lockdep_chains_ops);
177}
178
179static const struct file_operations proc_lockdep_chains_operations = {
180 .open = lockdep_chains_open,
181 .read = seq_read,
182 .llseek = seq_lseek,
183 .release = seq_release,
184};
185#endif /* CONFIG_PROVE_LOCKING */
186
187static void lockdep_stats_debug_show(struct seq_file *m)
188{
189#ifdef CONFIG_DEBUG_LOCKDEP
190 unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
191 hi2 = debug_atomic_read(hardirqs_off_events),
192 hr1 = debug_atomic_read(redundant_hardirqs_on),
193 hr2 = debug_atomic_read(redundant_hardirqs_off),
194 si1 = debug_atomic_read(softirqs_on_events),
195 si2 = debug_atomic_read(softirqs_off_events),
196 sr1 = debug_atomic_read(redundant_softirqs_on),
197 sr2 = debug_atomic_read(redundant_softirqs_off);
198
199 seq_printf(m, " chain lookup misses: %11llu\n",
200 debug_atomic_read(chain_lookup_misses));
201 seq_printf(m, " chain lookup hits: %11llu\n",
202 debug_atomic_read(chain_lookup_hits));
203 seq_printf(m, " cyclic checks: %11llu\n",
204 debug_atomic_read(nr_cyclic_checks));
205 seq_printf(m, " redundant checks: %11llu\n",
206 debug_atomic_read(nr_redundant_checks));
207 seq_printf(m, " redundant links: %11llu\n",
208 debug_atomic_read(nr_redundant));
209 seq_printf(m, " find-mask forwards checks: %11llu\n",
210 debug_atomic_read(nr_find_usage_forwards_checks));
211 seq_printf(m, " find-mask backwards checks: %11llu\n",
212 debug_atomic_read(nr_find_usage_backwards_checks));
213
214 seq_printf(m, " hardirq on events: %11llu\n", hi1);
215 seq_printf(m, " hardirq off events: %11llu\n", hi2);
216 seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
217 seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
218 seq_printf(m, " softirq on events: %11llu\n", si1);
219 seq_printf(m, " softirq off events: %11llu\n", si2);
220 seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
221 seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
222#endif
223}
224
225static int lockdep_stats_show(struct seq_file *m, void *v)
226{
227 struct lock_class *class;
228 unsigned long nr_unused = 0, nr_uncategorized = 0,
229 nr_irq_safe = 0, nr_irq_unsafe = 0,
230 nr_softirq_safe = 0, nr_softirq_unsafe = 0,
231 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
232 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
233 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
234 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
235 sum_forward_deps = 0;
236
237 list_for_each_entry(class, &all_lock_classes, lock_entry) {
238
239 if (class->usage_mask == 0)
240 nr_unused++;
241 if (class->usage_mask == LOCKF_USED)
242 nr_uncategorized++;
243 if (class->usage_mask & LOCKF_USED_IN_IRQ)
244 nr_irq_safe++;
245 if (class->usage_mask & LOCKF_ENABLED_IRQ)
246 nr_irq_unsafe++;
247 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
248 nr_softirq_safe++;
249 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
250 nr_softirq_unsafe++;
251 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
252 nr_hardirq_safe++;
253 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
254 nr_hardirq_unsafe++;
255 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
256 nr_irq_read_safe++;
257 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
258 nr_irq_read_unsafe++;
259 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
260 nr_softirq_read_safe++;
261 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
262 nr_softirq_read_unsafe++;
263 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
264 nr_hardirq_read_safe++;
265 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
266 nr_hardirq_read_unsafe++;
267
268#ifdef CONFIG_PROVE_LOCKING
269 sum_forward_deps += lockdep_count_forward_deps(class);
270#endif
271 }
272#ifdef CONFIG_DEBUG_LOCKDEP
273 DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
274#endif
275 seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
276 nr_lock_classes, MAX_LOCKDEP_KEYS);
277 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
278 nr_list_entries, MAX_LOCKDEP_ENTRIES);
279 seq_printf(m, " indirect dependencies: %11lu\n",
280 sum_forward_deps);
281
282 /*
283 * Total number of dependencies:
284 *
285 * All irq-safe locks may nest inside irq-unsafe locks,
286 * plus all the other known dependencies:
287 */
288 seq_printf(m, " all direct dependencies: %11lu\n",
289 nr_irq_unsafe * nr_irq_safe +
290 nr_hardirq_unsafe * nr_hardirq_safe +
291 nr_list_entries);
292
293#ifdef CONFIG_PROVE_LOCKING
294 seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
295 nr_lock_chains, MAX_LOCKDEP_CHAINS);
296 seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
297 nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
298#endif
299
300#ifdef CONFIG_TRACE_IRQFLAGS
301 seq_printf(m, " in-hardirq chains: %11u\n",
302 nr_hardirq_chains);
303 seq_printf(m, " in-softirq chains: %11u\n",
304 nr_softirq_chains);
305#endif
306 seq_printf(m, " in-process chains: %11u\n",
307 nr_process_chains);
308 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
309 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
310 seq_printf(m, " combined max dependencies: %11u\n",
311 (nr_hardirq_chains + 1) *
312 (nr_softirq_chains + 1) *
313 (nr_process_chains + 1)
314 );
315 seq_printf(m, " hardirq-safe locks: %11lu\n",
316 nr_hardirq_safe);
317 seq_printf(m, " hardirq-unsafe locks: %11lu\n",
318 nr_hardirq_unsafe);
319 seq_printf(m, " softirq-safe locks: %11lu\n",
320 nr_softirq_safe);
321 seq_printf(m, " softirq-unsafe locks: %11lu\n",
322 nr_softirq_unsafe);
323 seq_printf(m, " irq-safe locks: %11lu\n",
324 nr_irq_safe);
325 seq_printf(m, " irq-unsafe locks: %11lu\n",
326 nr_irq_unsafe);
327
328 seq_printf(m, " hardirq-read-safe locks: %11lu\n",
329 nr_hardirq_read_safe);
330 seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
331 nr_hardirq_read_unsafe);
332 seq_printf(m, " softirq-read-safe locks: %11lu\n",
333 nr_softirq_read_safe);
334 seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
335 nr_softirq_read_unsafe);
336 seq_printf(m, " irq-read-safe locks: %11lu\n",
337 nr_irq_read_safe);
338 seq_printf(m, " irq-read-unsafe locks: %11lu\n",
339 nr_irq_read_unsafe);
340
341 seq_printf(m, " uncategorized locks: %11lu\n",
342 nr_uncategorized);
343 seq_printf(m, " unused locks: %11lu\n",
344 nr_unused);
345 seq_printf(m, " max locking depth: %11u\n",
346 max_lockdep_depth);
347#ifdef CONFIG_PROVE_LOCKING
348 seq_printf(m, " max bfs queue depth: %11u\n",
349 max_bfs_queue_depth);
350#endif
351 lockdep_stats_debug_show(m);
352 seq_printf(m, " debug_locks: %11u\n",
353 debug_locks);
354
355 return 0;
356}
357
358static int lockdep_stats_open(struct inode *inode, struct file *file)
359{
360 return single_open(file, lockdep_stats_show, NULL);
361}
362
363static const struct file_operations proc_lockdep_stats_operations = {
364 .open = lockdep_stats_open,
365 .read = seq_read,
366 .llseek = seq_lseek,
367 .release = single_release,
368};
369
370#ifdef CONFIG_LOCK_STAT
371
372struct lock_stat_data {
373 struct lock_class *class;
374 struct lock_class_stats stats;
375};
376
377struct lock_stat_seq {
378 struct lock_stat_data *iter_end;
379 struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
380};
381
382/*
383 * sort on absolute number of contentions
384 */
385static int lock_stat_cmp(const void *l, const void *r)
386{
387 const struct lock_stat_data *dl = l, *dr = r;
388 unsigned long nl, nr;
389
390 nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
391 nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
392
393 return nr - nl;
394}
395
396static void seq_line(struct seq_file *m, char c, int offset, int length)
397{
398 int i;
399
400 for (i = 0; i < offset; i++)
401 seq_puts(m, " ");
402 for (i = 0; i < length; i++)
403 seq_printf(m, "%c", c);
404 seq_puts(m, "\n");
405}
406
407static void snprint_time(char *buf, size_t bufsiz, s64 nr)
408{
409 s64 div;
410 s32 rem;
411
412 nr += 5; /* for display rounding */
413 div = div_s64_rem(nr, 1000, &rem);
414 snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
415}
416
417static void seq_time(struct seq_file *m, s64 time)
418{
419 char num[15];
420
421 snprint_time(num, sizeof(num), time);
422 seq_printf(m, " %14s", num);
423}
424
425static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
426{
427 seq_printf(m, "%14lu", lt->nr);
428 seq_time(m, lt->min);
429 seq_time(m, lt->max);
430 seq_time(m, lt->total);
431 seq_time(m, lt->nr ? div_s64(lt->total, lt->nr) : 0);
432}
433
434static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
435{
436 struct lockdep_subclass_key *ckey;
437 struct lock_class_stats *stats;
438 struct lock_class *class;
439 const char *cname;
440 int i, namelen;
441 char name[39];
442
443 class = data->class;
444 stats = &data->stats;
445
446 namelen = 38;
447 if (class->name_version > 1)
448 namelen -= 2; /* XXX truncates versions > 9 */
449 if (class->subclass)
450 namelen -= 2;
451
452 rcu_read_lock_sched();
453 cname = rcu_dereference_sched(class->name);
454 ckey = rcu_dereference_sched(class->key);
455
456 if (!cname && !ckey) {
457 rcu_read_unlock_sched();
458 return;
459
460 } else if (!cname) {
461 char str[KSYM_NAME_LEN];
462 const char *key_name;
463
464 key_name = __get_key_name(ckey, str);
465 snprintf(name, namelen, "%s", key_name);
466 } else {
467 snprintf(name, namelen, "%s", cname);
468 }
469 rcu_read_unlock_sched();
470
471 namelen = strlen(name);
472 if (class->name_version > 1) {
473 snprintf(name+namelen, 3, "#%d", class->name_version);
474 namelen += 2;
475 }
476 if (class->subclass) {
477 snprintf(name+namelen, 3, "/%d", class->subclass);
478 namelen += 2;
479 }
480
481 if (stats->write_holdtime.nr) {
482 if (stats->read_holdtime.nr)
483 seq_printf(m, "%38s-W:", name);
484 else
485 seq_printf(m, "%40s:", name);
486
487 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
488 seq_lock_time(m, &stats->write_waittime);
489 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
490 seq_lock_time(m, &stats->write_holdtime);
491 seq_puts(m, "\n");
492 }
493
494 if (stats->read_holdtime.nr) {
495 seq_printf(m, "%38s-R:", name);
496 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
497 seq_lock_time(m, &stats->read_waittime);
498 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
499 seq_lock_time(m, &stats->read_holdtime);
500 seq_puts(m, "\n");
501 }
502
503 if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
504 return;
505
506 if (stats->read_holdtime.nr)
507 namelen += 2;
508
509 for (i = 0; i < LOCKSTAT_POINTS; i++) {
510 char ip[32];
511
512 if (class->contention_point[i] == 0)
513 break;
514
515 if (!i)
516 seq_line(m, '-', 40-namelen, namelen);
517
518 snprintf(ip, sizeof(ip), "[<%p>]",
519 (void *)class->contention_point[i]);
520 seq_printf(m, "%40s %14lu %29s %pS\n",
521 name, stats->contention_point[i],
522 ip, (void *)class->contention_point[i]);
523 }
524 for (i = 0; i < LOCKSTAT_POINTS; i++) {
525 char ip[32];
526
527 if (class->contending_point[i] == 0)
528 break;
529
530 if (!i)
531 seq_line(m, '-', 40-namelen, namelen);
532
533 snprintf(ip, sizeof(ip), "[<%p>]",
534 (void *)class->contending_point[i]);
535 seq_printf(m, "%40s %14lu %29s %pS\n",
536 name, stats->contending_point[i],
537 ip, (void *)class->contending_point[i]);
538 }
539 if (i) {
540 seq_puts(m, "\n");
541 seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
542 seq_puts(m, "\n");
543 }
544}
545
546static void seq_header(struct seq_file *m)
547{
548 seq_puts(m, "lock_stat version 0.4\n");
549
550 if (unlikely(!debug_locks))
551 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
552
553 seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
554 seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
555 "%14s %14s\n",
556 "class name",
557 "con-bounces",
558 "contentions",
559 "waittime-min",
560 "waittime-max",
561 "waittime-total",
562 "waittime-avg",
563 "acq-bounces",
564 "acquisitions",
565 "holdtime-min",
566 "holdtime-max",
567 "holdtime-total",
568 "holdtime-avg");
569 seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
570 seq_printf(m, "\n");
571}
572
573static void *ls_start(struct seq_file *m, loff_t *pos)
574{
575 struct lock_stat_seq *data = m->private;
576 struct lock_stat_data *iter;
577
578 if (*pos == 0)
579 return SEQ_START_TOKEN;
580
581 iter = data->stats + (*pos - 1);
582 if (iter >= data->iter_end)
583 iter = NULL;
584
585 return iter;
586}
587
588static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
589{
590 (*pos)++;
591 return ls_start(m, pos);
592}
593
594static void ls_stop(struct seq_file *m, void *v)
595{
596}
597
598static int ls_show(struct seq_file *m, void *v)
599{
600 if (v == SEQ_START_TOKEN)
601 seq_header(m);
602 else
603 seq_stats(m, v);
604
605 return 0;
606}
607
608static const struct seq_operations lockstat_ops = {
609 .start = ls_start,
610 .next = ls_next,
611 .stop = ls_stop,
612 .show = ls_show,
613};
614
615static int lock_stat_open(struct inode *inode, struct file *file)
616{
617 int res;
618 struct lock_class *class;
619 struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
620
621 if (!data)
622 return -ENOMEM;
623
624 res = seq_open(file, &lockstat_ops);
625 if (!res) {
626 struct lock_stat_data *iter = data->stats;
627 struct seq_file *m = file->private_data;
628
629 list_for_each_entry(class, &all_lock_classes, lock_entry) {
630 iter->class = class;
631 iter->stats = lock_stats(class);
632 iter++;
633 }
634 data->iter_end = iter;
635
636 sort(data->stats, data->iter_end - data->stats,
637 sizeof(struct lock_stat_data),
638 lock_stat_cmp, NULL);
639
640 m->private = data;
641 } else
642 vfree(data);
643
644 return res;
645}
646
647static ssize_t lock_stat_write(struct file *file, const char __user *buf,
648 size_t count, loff_t *ppos)
649{
650 struct lock_class *class;
651 char c;
652
653 if (count) {
654 if (get_user(c, buf))
655 return -EFAULT;
656
657 if (c != '0')
658 return count;
659
660 list_for_each_entry(class, &all_lock_classes, lock_entry)
661 clear_lock_stats(class);
662 }
663 return count;
664}
665
666static int lock_stat_release(struct inode *inode, struct file *file)
667{
668 struct seq_file *seq = file->private_data;
669
670 vfree(seq->private);
671 return seq_release(inode, file);
672}
673
674static const struct file_operations proc_lock_stat_operations = {
675 .open = lock_stat_open,
676 .write = lock_stat_write,
677 .read = seq_read,
678 .llseek = seq_lseek,
679 .release = lock_stat_release,
680};
681#endif /* CONFIG_LOCK_STAT */
682
683static int __init lockdep_proc_init(void)
684{
685 proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
686#ifdef CONFIG_PROVE_LOCKING
687 proc_create("lockdep_chains", S_IRUSR, NULL,
688 &proc_lockdep_chains_operations);
689#endif
690 proc_create("lockdep_stats", S_IRUSR, NULL,
691 &proc_lockdep_stats_operations);
692
693#ifdef CONFIG_LOCK_STAT
694 proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
695 &proc_lock_stat_operations);
696#endif
697
698 return 0;
699}
700
701__initcall(lockdep_proc_init);
702
1/*
2 * kernel/lockdep_proc.c
3 *
4 * Runtime locking correctness validator
5 *
6 * Started by Ingo Molnar:
7 *
8 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
10 *
11 * Code for /proc/lockdep and /proc/lockdep_stats:
12 *
13 */
14#include <linux/export.h>
15#include <linux/proc_fs.h>
16#include <linux/seq_file.h>
17#include <linux/kallsyms.h>
18#include <linux/debug_locks.h>
19#include <linux/vmalloc.h>
20#include <linux/sort.h>
21#include <asm/uaccess.h>
22#include <asm/div64.h>
23
24#include "lockdep_internals.h"
25
26static void *l_next(struct seq_file *m, void *v, loff_t *pos)
27{
28 return seq_list_next(v, &all_lock_classes, pos);
29}
30
31static void *l_start(struct seq_file *m, loff_t *pos)
32{
33 return seq_list_start_head(&all_lock_classes, *pos);
34}
35
36static void l_stop(struct seq_file *m, void *v)
37{
38}
39
40static void print_name(struct seq_file *m, struct lock_class *class)
41{
42 char str[KSYM_NAME_LEN];
43 const char *name = class->name;
44
45 if (!name) {
46 name = __get_key_name(class->key, str);
47 seq_printf(m, "%s", name);
48 } else{
49 seq_printf(m, "%s", name);
50 if (class->name_version > 1)
51 seq_printf(m, "#%d", class->name_version);
52 if (class->subclass)
53 seq_printf(m, "/%d", class->subclass);
54 }
55}
56
57static int l_show(struct seq_file *m, void *v)
58{
59 struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
60 struct lock_list *entry;
61 char usage[LOCK_USAGE_CHARS];
62
63 if (v == &all_lock_classes) {
64 seq_printf(m, "all lock classes:\n");
65 return 0;
66 }
67
68 seq_printf(m, "%p", class->key);
69#ifdef CONFIG_DEBUG_LOCKDEP
70 seq_printf(m, " OPS:%8ld", class->ops);
71#endif
72#ifdef CONFIG_PROVE_LOCKING
73 seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
74 seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
75#endif
76
77 get_usage_chars(class, usage);
78 seq_printf(m, " %s", usage);
79
80 seq_printf(m, ": ");
81 print_name(m, class);
82 seq_puts(m, "\n");
83
84 list_for_each_entry(entry, &class->locks_after, entry) {
85 if (entry->distance == 1) {
86 seq_printf(m, " -> [%p] ", entry->class->key);
87 print_name(m, entry->class);
88 seq_puts(m, "\n");
89 }
90 }
91 seq_puts(m, "\n");
92
93 return 0;
94}
95
96static const struct seq_operations lockdep_ops = {
97 .start = l_start,
98 .next = l_next,
99 .stop = l_stop,
100 .show = l_show,
101};
102
103static int lockdep_open(struct inode *inode, struct file *file)
104{
105 return seq_open(file, &lockdep_ops);
106}
107
108static const struct file_operations proc_lockdep_operations = {
109 .open = lockdep_open,
110 .read = seq_read,
111 .llseek = seq_lseek,
112 .release = seq_release,
113};
114
115#ifdef CONFIG_PROVE_LOCKING
116static void *lc_start(struct seq_file *m, loff_t *pos)
117{
118 if (*pos == 0)
119 return SEQ_START_TOKEN;
120
121 if (*pos - 1 < nr_lock_chains)
122 return lock_chains + (*pos - 1);
123
124 return NULL;
125}
126
127static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
128{
129 (*pos)++;
130 return lc_start(m, pos);
131}
132
133static void lc_stop(struct seq_file *m, void *v)
134{
135}
136
137static int lc_show(struct seq_file *m, void *v)
138{
139 struct lock_chain *chain = v;
140 struct lock_class *class;
141 int i;
142
143 if (v == SEQ_START_TOKEN) {
144 if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
145 seq_printf(m, "(buggered) ");
146 seq_printf(m, "all lock chains:\n");
147 return 0;
148 }
149
150 seq_printf(m, "irq_context: %d\n", chain->irq_context);
151
152 for (i = 0; i < chain->depth; i++) {
153 class = lock_chain_get_class(chain, i);
154 if (!class->key)
155 continue;
156
157 seq_printf(m, "[%p] ", class->key);
158 print_name(m, class);
159 seq_puts(m, "\n");
160 }
161 seq_puts(m, "\n");
162
163 return 0;
164}
165
166static const struct seq_operations lockdep_chains_ops = {
167 .start = lc_start,
168 .next = lc_next,
169 .stop = lc_stop,
170 .show = lc_show,
171};
172
173static int lockdep_chains_open(struct inode *inode, struct file *file)
174{
175 return seq_open(file, &lockdep_chains_ops);
176}
177
178static const struct file_operations proc_lockdep_chains_operations = {
179 .open = lockdep_chains_open,
180 .read = seq_read,
181 .llseek = seq_lseek,
182 .release = seq_release,
183};
184#endif /* CONFIG_PROVE_LOCKING */
185
186static void lockdep_stats_debug_show(struct seq_file *m)
187{
188#ifdef CONFIG_DEBUG_LOCKDEP
189 unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
190 hi2 = debug_atomic_read(hardirqs_off_events),
191 hr1 = debug_atomic_read(redundant_hardirqs_on),
192 hr2 = debug_atomic_read(redundant_hardirqs_off),
193 si1 = debug_atomic_read(softirqs_on_events),
194 si2 = debug_atomic_read(softirqs_off_events),
195 sr1 = debug_atomic_read(redundant_softirqs_on),
196 sr2 = debug_atomic_read(redundant_softirqs_off);
197
198 seq_printf(m, " chain lookup misses: %11llu\n",
199 debug_atomic_read(chain_lookup_misses));
200 seq_printf(m, " chain lookup hits: %11llu\n",
201 debug_atomic_read(chain_lookup_hits));
202 seq_printf(m, " cyclic checks: %11llu\n",
203 debug_atomic_read(nr_cyclic_checks));
204 seq_printf(m, " find-mask forwards checks: %11llu\n",
205 debug_atomic_read(nr_find_usage_forwards_checks));
206 seq_printf(m, " find-mask backwards checks: %11llu\n",
207 debug_atomic_read(nr_find_usage_backwards_checks));
208
209 seq_printf(m, " hardirq on events: %11llu\n", hi1);
210 seq_printf(m, " hardirq off events: %11llu\n", hi2);
211 seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
212 seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
213 seq_printf(m, " softirq on events: %11llu\n", si1);
214 seq_printf(m, " softirq off events: %11llu\n", si2);
215 seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
216 seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
217#endif
218}
219
220static int lockdep_stats_show(struct seq_file *m, void *v)
221{
222 struct lock_class *class;
223 unsigned long nr_unused = 0, nr_uncategorized = 0,
224 nr_irq_safe = 0, nr_irq_unsafe = 0,
225 nr_softirq_safe = 0, nr_softirq_unsafe = 0,
226 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
227 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
228 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
229 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
230 sum_forward_deps = 0;
231
232 list_for_each_entry(class, &all_lock_classes, lock_entry) {
233
234 if (class->usage_mask == 0)
235 nr_unused++;
236 if (class->usage_mask == LOCKF_USED)
237 nr_uncategorized++;
238 if (class->usage_mask & LOCKF_USED_IN_IRQ)
239 nr_irq_safe++;
240 if (class->usage_mask & LOCKF_ENABLED_IRQ)
241 nr_irq_unsafe++;
242 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
243 nr_softirq_safe++;
244 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
245 nr_softirq_unsafe++;
246 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
247 nr_hardirq_safe++;
248 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
249 nr_hardirq_unsafe++;
250 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
251 nr_irq_read_safe++;
252 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
253 nr_irq_read_unsafe++;
254 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
255 nr_softirq_read_safe++;
256 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
257 nr_softirq_read_unsafe++;
258 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
259 nr_hardirq_read_safe++;
260 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
261 nr_hardirq_read_unsafe++;
262
263#ifdef CONFIG_PROVE_LOCKING
264 sum_forward_deps += lockdep_count_forward_deps(class);
265#endif
266 }
267#ifdef CONFIG_DEBUG_LOCKDEP
268 DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
269#endif
270 seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
271 nr_lock_classes, MAX_LOCKDEP_KEYS);
272 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
273 nr_list_entries, MAX_LOCKDEP_ENTRIES);
274 seq_printf(m, " indirect dependencies: %11lu\n",
275 sum_forward_deps);
276
277 /*
278 * Total number of dependencies:
279 *
280 * All irq-safe locks may nest inside irq-unsafe locks,
281 * plus all the other known dependencies:
282 */
283 seq_printf(m, " all direct dependencies: %11lu\n",
284 nr_irq_unsafe * nr_irq_safe +
285 nr_hardirq_unsafe * nr_hardirq_safe +
286 nr_list_entries);
287
288#ifdef CONFIG_PROVE_LOCKING
289 seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
290 nr_lock_chains, MAX_LOCKDEP_CHAINS);
291 seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
292 nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
293#endif
294
295#ifdef CONFIG_TRACE_IRQFLAGS
296 seq_printf(m, " in-hardirq chains: %11u\n",
297 nr_hardirq_chains);
298 seq_printf(m, " in-softirq chains: %11u\n",
299 nr_softirq_chains);
300#endif
301 seq_printf(m, " in-process chains: %11u\n",
302 nr_process_chains);
303 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
304 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
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 return 0;
351}
352
353static int lockdep_stats_open(struct inode *inode, struct file *file)
354{
355 return single_open(file, lockdep_stats_show, NULL);
356}
357
358static const struct file_operations proc_lockdep_stats_operations = {
359 .open = lockdep_stats_open,
360 .read = seq_read,
361 .llseek = seq_lseek,
362 .release = single_release,
363};
364
365#ifdef CONFIG_LOCK_STAT
366
367struct lock_stat_data {
368 struct lock_class *class;
369 struct lock_class_stats stats;
370};
371
372struct 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 */
380static 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
391static 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
402static 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
412static 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
420static 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 ? div_s64(lt->total, lt->nr) : 0);
427}
428
429static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
430{
431 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
541static 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
568static 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
583static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
584{
585 (*pos)++;
586 return ls_start(m, pos);
587}
588
589static void ls_stop(struct seq_file *m, void *v)
590{
591}
592
593static 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
603static const struct seq_operations lockstat_ops = {
604 .start = ls_start,
605 .next = ls_next,
606 .stop = ls_stop,
607 .show = ls_show,
608};
609
610static 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
642static 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
661static 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
669static const struct file_operations proc_lock_stat_operations = {
670 .open = lock_stat_open,
671 .write = lock_stat_write,
672 .read = seq_read,
673 .llseek = seq_lseek,
674 .release = lock_stat_release,
675};
676#endif /* CONFIG_LOCK_STAT */
677
678static int __init lockdep_proc_init(void)
679{
680 proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
681#ifdef CONFIG_PROVE_LOCKING
682 proc_create("lockdep_chains", S_IRUSR, NULL,
683 &proc_lockdep_chains_operations);
684#endif
685 proc_create("lockdep_stats", S_IRUSR, NULL,
686 &proc_lockdep_stats_operations);
687
688#ifdef CONFIG_LOCK_STAT
689 proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
690 &proc_lock_stat_operations);
691#endif
692
693 return 0;
694}
695
696__initcall(lockdep_proc_init);
697