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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 <pzijlstr@redhat.com>
10 *
11 * Code for /proc/lockdep and /proc/lockdep_stats:
12 *
13 */
14#include <linux/module.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[128];
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 seq_printf(m, "all lock chains:\n");
145 return 0;
146 }
147
148 seq_printf(m, "irq_context: %d\n", 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
171static int lockdep_chains_open(struct inode *inode, struct file *file)
172{
173 return seq_open(file, &lockdep_chains_ops);
174}
175
176static const struct file_operations proc_lockdep_chains_operations = {
177 .open = lockdep_chains_open,
178 .read = seq_read,
179 .llseek = seq_lseek,
180 .release = seq_release,
181};
182#endif /* CONFIG_PROVE_LOCKING */
183
184static void lockdep_stats_debug_show(struct seq_file *m)
185{
186#ifdef CONFIG_DEBUG_LOCKDEP
187 unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
188 hi2 = debug_atomic_read(hardirqs_off_events),
189 hr1 = debug_atomic_read(redundant_hardirqs_on),
190 hr2 = debug_atomic_read(redundant_hardirqs_off),
191 si1 = debug_atomic_read(softirqs_on_events),
192 si2 = debug_atomic_read(softirqs_off_events),
193 sr1 = debug_atomic_read(redundant_softirqs_on),
194 sr2 = debug_atomic_read(redundant_softirqs_off);
195
196 seq_printf(m, " chain lookup misses: %11llu\n",
197 debug_atomic_read(chain_lookup_misses));
198 seq_printf(m, " chain lookup hits: %11llu\n",
199 debug_atomic_read(chain_lookup_hits));
200 seq_printf(m, " cyclic checks: %11llu\n",
201 debug_atomic_read(nr_cyclic_checks));
202 seq_printf(m, " find-mask forwards checks: %11llu\n",
203 debug_atomic_read(nr_find_usage_forwards_checks));
204 seq_printf(m, " find-mask backwards checks: %11llu\n",
205 debug_atomic_read(nr_find_usage_backwards_checks));
206
207 seq_printf(m, " hardirq on events: %11llu\n", hi1);
208 seq_printf(m, " hardirq off events: %11llu\n", hi2);
209 seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
210 seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
211 seq_printf(m, " softirq on events: %11llu\n", si1);
212 seq_printf(m, " softirq off events: %11llu\n", si2);
213 seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
214 seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
215#endif
216}
217
218static int lockdep_stats_show(struct seq_file *m, void *v)
219{
220 struct lock_class *class;
221 unsigned long nr_unused = 0, nr_uncategorized = 0,
222 nr_irq_safe = 0, nr_irq_unsafe = 0,
223 nr_softirq_safe = 0, nr_softirq_unsafe = 0,
224 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
225 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
226 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
227 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
228 sum_forward_deps = 0;
229
230 list_for_each_entry(class, &all_lock_classes, lock_entry) {
231
232 if (class->usage_mask == 0)
233 nr_unused++;
234 if (class->usage_mask == LOCKF_USED)
235 nr_uncategorized++;
236 if (class->usage_mask & LOCKF_USED_IN_IRQ)
237 nr_irq_safe++;
238 if (class->usage_mask & LOCKF_ENABLED_IRQ)
239 nr_irq_unsafe++;
240 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
241 nr_softirq_safe++;
242 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
243 nr_softirq_unsafe++;
244 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
245 nr_hardirq_safe++;
246 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
247 nr_hardirq_unsafe++;
248 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
249 nr_irq_read_safe++;
250 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
251 nr_irq_read_unsafe++;
252 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
253 nr_softirq_read_safe++;
254 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
255 nr_softirq_read_unsafe++;
256 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
257 nr_hardirq_read_safe++;
258 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
259 nr_hardirq_read_unsafe++;
260
261#ifdef CONFIG_PROVE_LOCKING
262 sum_forward_deps += lockdep_count_forward_deps(class);
263#endif
264 }
265#ifdef CONFIG_DEBUG_LOCKDEP
266 DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
267#endif
268 seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
269 nr_lock_classes, MAX_LOCKDEP_KEYS);
270 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
271 nr_list_entries, MAX_LOCKDEP_ENTRIES);
272 seq_printf(m, " indirect dependencies: %11lu\n",
273 sum_forward_deps);
274
275 /*
276 * Total number of dependencies:
277 *
278 * All irq-safe locks may nest inside irq-unsafe locks,
279 * plus all the other known dependencies:
280 */
281 seq_printf(m, " all direct dependencies: %11lu\n",
282 nr_irq_unsafe * nr_irq_safe +
283 nr_hardirq_unsafe * nr_hardirq_safe +
284 nr_list_entries);
285
286#ifdef CONFIG_PROVE_LOCKING
287 seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
288 nr_lock_chains, MAX_LOCKDEP_CHAINS);
289 seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
290 nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
291#endif
292
293#ifdef CONFIG_TRACE_IRQFLAGS
294 seq_printf(m, " in-hardirq chains: %11u\n",
295 nr_hardirq_chains);
296 seq_printf(m, " in-softirq chains: %11u\n",
297 nr_softirq_chains);
298#endif
299 seq_printf(m, " in-process chains: %11u\n",
300 nr_process_chains);
301 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
302 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
303 seq_printf(m, " combined max dependencies: %11u\n",
304 (nr_hardirq_chains + 1) *
305 (nr_softirq_chains + 1) *
306 (nr_process_chains + 1)
307 );
308 seq_printf(m, " hardirq-safe locks: %11lu\n",
309 nr_hardirq_safe);
310 seq_printf(m, " hardirq-unsafe locks: %11lu\n",
311 nr_hardirq_unsafe);
312 seq_printf(m, " softirq-safe locks: %11lu\n",
313 nr_softirq_safe);
314 seq_printf(m, " softirq-unsafe locks: %11lu\n",
315 nr_softirq_unsafe);
316 seq_printf(m, " irq-safe locks: %11lu\n",
317 nr_irq_safe);
318 seq_printf(m, " irq-unsafe locks: %11lu\n",
319 nr_irq_unsafe);
320
321 seq_printf(m, " hardirq-read-safe locks: %11lu\n",
322 nr_hardirq_read_safe);
323 seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
324 nr_hardirq_read_unsafe);
325 seq_printf(m, " softirq-read-safe locks: %11lu\n",
326 nr_softirq_read_safe);
327 seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
328 nr_softirq_read_unsafe);
329 seq_printf(m, " irq-read-safe locks: %11lu\n",
330 nr_irq_read_safe);
331 seq_printf(m, " irq-read-unsafe locks: %11lu\n",
332 nr_irq_read_unsafe);
333
334 seq_printf(m, " uncategorized locks: %11lu\n",
335 nr_uncategorized);
336 seq_printf(m, " unused locks: %11lu\n",
337 nr_unused);
338 seq_printf(m, " max locking depth: %11u\n",
339 max_lockdep_depth);
340#ifdef CONFIG_PROVE_LOCKING
341 seq_printf(m, " max bfs queue depth: %11u\n",
342 max_bfs_queue_depth);
343#endif
344 lockdep_stats_debug_show(m);
345 seq_printf(m, " debug_locks: %11u\n",
346 debug_locks);
347
348 return 0;
349}
350
351static int lockdep_stats_open(struct inode *inode, struct file *file)
352{
353 return single_open(file, lockdep_stats_show, NULL);
354}
355
356static const struct file_operations proc_lockdep_stats_operations = {
357 .open = lockdep_stats_open,
358 .read = seq_read,
359 .llseek = seq_lseek,
360 .release = single_release,
361};
362
363#ifdef CONFIG_LOCK_STAT
364
365struct lock_stat_data {
366 struct lock_class *class;
367 struct lock_class_stats stats;
368};
369
370struct lock_stat_seq {
371 struct lock_stat_data *iter_end;
372 struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
373};
374
375/*
376 * sort on absolute number of contentions
377 */
378static int lock_stat_cmp(const void *l, const void *r)
379{
380 const struct lock_stat_data *dl = l, *dr = r;
381 unsigned long nl, nr;
382
383 nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
384 nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
385
386 return nr - nl;
387}
388
389static void seq_line(struct seq_file *m, char c, int offset, int length)
390{
391 int i;
392
393 for (i = 0; i < offset; i++)
394 seq_puts(m, " ");
395 for (i = 0; i < length; i++)
396 seq_printf(m, "%c", c);
397 seq_puts(m, "\n");
398}
399
400static void snprint_time(char *buf, size_t bufsiz, s64 nr)
401{
402 s64 div;
403 s32 rem;
404
405 nr += 5; /* for display rounding */
406 div = div_s64_rem(nr, 1000, &rem);
407 snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
408}
409
410static void seq_time(struct seq_file *m, s64 time)
411{
412 char num[15];
413
414 snprint_time(num, sizeof(num), time);
415 seq_printf(m, " %14s", num);
416}
417
418static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
419{
420 seq_printf(m, "%14lu", lt->nr);
421 seq_time(m, lt->min);
422 seq_time(m, lt->max);
423 seq_time(m, lt->total);
424}
425
426static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
427{
428 char name[39];
429 struct lock_class *class;
430 struct lock_class_stats *stats;
431 int i, namelen;
432
433 class = data->class;
434 stats = &data->stats;
435
436 namelen = 38;
437 if (class->name_version > 1)
438 namelen -= 2; /* XXX truncates versions > 9 */
439 if (class->subclass)
440 namelen -= 2;
441
442 if (!class->name) {
443 char str[KSYM_NAME_LEN];
444 const char *key_name;
445
446 key_name = __get_key_name(class->key, str);
447 snprintf(name, namelen, "%s", key_name);
448 } else {
449 snprintf(name, namelen, "%s", class->name);
450 }
451 namelen = strlen(name);
452 if (class->name_version > 1) {
453 snprintf(name+namelen, 3, "#%d", class->name_version);
454 namelen += 2;
455 }
456 if (class->subclass) {
457 snprintf(name+namelen, 3, "/%d", class->subclass);
458 namelen += 2;
459 }
460
461 if (stats->write_holdtime.nr) {
462 if (stats->read_holdtime.nr)
463 seq_printf(m, "%38s-W:", name);
464 else
465 seq_printf(m, "%40s:", name);
466
467 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
468 seq_lock_time(m, &stats->write_waittime);
469 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
470 seq_lock_time(m, &stats->write_holdtime);
471 seq_puts(m, "\n");
472 }
473
474 if (stats->read_holdtime.nr) {
475 seq_printf(m, "%38s-R:", name);
476 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
477 seq_lock_time(m, &stats->read_waittime);
478 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
479 seq_lock_time(m, &stats->read_holdtime);
480 seq_puts(m, "\n");
481 }
482
483 if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
484 return;
485
486 if (stats->read_holdtime.nr)
487 namelen += 2;
488
489 for (i = 0; i < LOCKSTAT_POINTS; i++) {
490 char ip[32];
491
492 if (class->contention_point[i] == 0)
493 break;
494
495 if (!i)
496 seq_line(m, '-', 40-namelen, namelen);
497
498 snprintf(ip, sizeof(ip), "[<%p>]",
499 (void *)class->contention_point[i]);
500 seq_printf(m, "%40s %14lu %29s %pS\n",
501 name, stats->contention_point[i],
502 ip, (void *)class->contention_point[i]);
503 }
504 for (i = 0; i < LOCKSTAT_POINTS; i++) {
505 char ip[32];
506
507 if (class->contending_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->contending_point[i]);
515 seq_printf(m, "%40s %14lu %29s %pS\n",
516 name, stats->contending_point[i],
517 ip, (void *)class->contending_point[i]);
518 }
519 if (i) {
520 seq_puts(m, "\n");
521 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
522 seq_puts(m, "\n");
523 }
524}
525
526static void seq_header(struct seq_file *m)
527{
528 seq_printf(m, "lock_stat version 0.3\n");
529
530 if (unlikely(!debug_locks))
531 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
532
533 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
534 seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
535 "%14s %14s\n",
536 "class name",
537 "con-bounces",
538 "contentions",
539 "waittime-min",
540 "waittime-max",
541 "waittime-total",
542 "acq-bounces",
543 "acquisitions",
544 "holdtime-min",
545 "holdtime-max",
546 "holdtime-total");
547 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
548 seq_printf(m, "\n");
549}
550
551static void *ls_start(struct seq_file *m, loff_t *pos)
552{
553 struct lock_stat_seq *data = m->private;
554 struct lock_stat_data *iter;
555
556 if (*pos == 0)
557 return SEQ_START_TOKEN;
558
559 iter = data->stats + (*pos - 1);
560 if (iter >= data->iter_end)
561 iter = NULL;
562
563 return iter;
564}
565
566static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
567{
568 (*pos)++;
569 return ls_start(m, pos);
570}
571
572static void ls_stop(struct seq_file *m, void *v)
573{
574}
575
576static int ls_show(struct seq_file *m, void *v)
577{
578 if (v == SEQ_START_TOKEN)
579 seq_header(m);
580 else
581 seq_stats(m, v);
582
583 return 0;
584}
585
586static const struct seq_operations lockstat_ops = {
587 .start = ls_start,
588 .next = ls_next,
589 .stop = ls_stop,
590 .show = ls_show,
591};
592
593static int lock_stat_open(struct inode *inode, struct file *file)
594{
595 int res;
596 struct lock_class *class;
597 struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
598
599 if (!data)
600 return -ENOMEM;
601
602 res = seq_open(file, &lockstat_ops);
603 if (!res) {
604 struct lock_stat_data *iter = data->stats;
605 struct seq_file *m = file->private_data;
606
607 list_for_each_entry(class, &all_lock_classes, lock_entry) {
608 iter->class = class;
609 iter->stats = lock_stats(class);
610 iter++;
611 }
612 data->iter_end = iter;
613
614 sort(data->stats, data->iter_end - data->stats,
615 sizeof(struct lock_stat_data),
616 lock_stat_cmp, NULL);
617
618 m->private = data;
619 } else
620 vfree(data);
621
622 return res;
623}
624
625static ssize_t lock_stat_write(struct file *file, const char __user *buf,
626 size_t count, loff_t *ppos)
627{
628 struct lock_class *class;
629 char c;
630
631 if (count) {
632 if (get_user(c, buf))
633 return -EFAULT;
634
635 if (c != '0')
636 return count;
637
638 list_for_each_entry(class, &all_lock_classes, lock_entry)
639 clear_lock_stats(class);
640 }
641 return count;
642}
643
644static int lock_stat_release(struct inode *inode, struct file *file)
645{
646 struct seq_file *seq = file->private_data;
647
648 vfree(seq->private);
649 return seq_release(inode, file);
650}
651
652static const struct file_operations proc_lock_stat_operations = {
653 .open = lock_stat_open,
654 .write = lock_stat_write,
655 .read = seq_read,
656 .llseek = seq_lseek,
657 .release = lock_stat_release,
658};
659#endif /* CONFIG_LOCK_STAT */
660
661static int __init lockdep_proc_init(void)
662{
663 proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
664#ifdef CONFIG_PROVE_LOCKING
665 proc_create("lockdep_chains", S_IRUSR, NULL,
666 &proc_lockdep_chains_operations);
667#endif
668 proc_create("lockdep_stats", S_IRUSR, NULL,
669 &proc_lockdep_stats_operations);
670
671#ifdef CONFIG_LOCK_STAT
672 proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
673 &proc_lock_stat_operations);
674#endif
675
676 return 0;
677}
678
679__initcall(lockdep_proc_init);
680