2 * kernel/lockdep_proc.c
4 * Runtime locking correctness validator
6 * Started by Ingo Molnar:
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>
11 * Code for /proc/lockdep and /proc/lockdep_stats:
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>
24 #include "lockdep_internals.h"
26 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
28 struct lock_class *class;
32 if (v == SEQ_START_TOKEN)
37 if (class->lock_entry.next != &all_lock_classes)
38 class = list_entry(class->lock_entry.next,
39 struct lock_class, lock_entry);
47 static void *l_start(struct seq_file *m, loff_t *pos)
49 struct lock_class *class;
53 return SEQ_START_TOKEN;
55 list_for_each_entry(class, &all_lock_classes, lock_entry) {
62 static void l_stop(struct seq_file *m, void *v)
66 static unsigned long count_forward_deps(struct lock_class *class)
68 struct lock_list *entry;
69 unsigned long ret = 1;
72 * Recurse this class's dependency list:
74 list_for_each_entry(entry, &class->locks_after, entry)
75 ret += count_forward_deps(entry->class);
80 static unsigned long count_backward_deps(struct lock_class *class)
82 struct lock_list *entry;
83 unsigned long ret = 1;
86 * Recurse this class's dependency list:
88 list_for_each_entry(entry, &class->locks_before, entry)
89 ret += count_backward_deps(entry->class);
94 static void print_name(struct seq_file *m, struct lock_class *class)
97 const char *name = class->name;
100 name = __get_key_name(class->key, str);
101 seq_printf(m, "%s", name);
103 seq_printf(m, "%s", name);
104 if (class->name_version > 1)
105 seq_printf(m, "#%d", class->name_version);
107 seq_printf(m, "/%d", class->subclass);
111 static int l_show(struct seq_file *m, void *v)
113 unsigned long nr_forward_deps, nr_backward_deps;
114 struct lock_class *class = v;
115 struct lock_list *entry;
118 if (v == SEQ_START_TOKEN) {
119 seq_printf(m, "all lock classes:\n");
123 seq_printf(m, "%p", class->key);
124 #ifdef CONFIG_DEBUG_LOCKDEP
125 seq_printf(m, " OPS:%8ld", class->ops);
127 nr_forward_deps = count_forward_deps(class);
128 seq_printf(m, " FD:%5ld", nr_forward_deps);
130 nr_backward_deps = count_backward_deps(class);
131 seq_printf(m, " BD:%5ld", nr_backward_deps);
133 get_usage_chars(class, &c1, &c2, &c3, &c4);
134 seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
137 print_name(m, class);
140 list_for_each_entry(entry, &class->locks_after, entry) {
141 if (entry->distance == 1) {
142 seq_printf(m, " -> [%p] ", entry->class->key);
143 print_name(m, entry->class);
152 static const struct seq_operations lockdep_ops = {
159 static int lockdep_open(struct inode *inode, struct file *file)
161 int res = seq_open(file, &lockdep_ops);
163 struct seq_file *m = file->private_data;
165 if (!list_empty(&all_lock_classes))
166 m->private = list_entry(all_lock_classes.next,
167 struct lock_class, lock_entry);
174 static const struct file_operations proc_lockdep_operations = {
175 .open = lockdep_open,
178 .release = seq_release,
181 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
183 struct lock_chain *chain;
187 if (v == SEQ_START_TOKEN)
192 if (*pos < nr_lock_chains)
193 chain = lock_chains + *pos;
201 static void *lc_start(struct seq_file *m, loff_t *pos)
204 return SEQ_START_TOKEN;
206 if (*pos < nr_lock_chains)
207 return lock_chains + *pos;
212 static void lc_stop(struct seq_file *m, void *v)
216 static int lc_show(struct seq_file *m, void *v)
218 struct lock_chain *chain = v;
219 struct lock_class *class;
222 if (v == SEQ_START_TOKEN) {
223 seq_printf(m, "all lock chains:\n");
227 seq_printf(m, "irq_context: %d\n", chain->irq_context);
229 for (i = 0; i < chain->depth; i++) {
230 class = lock_chain_get_class(chain, i);
231 seq_printf(m, "[%p] ", class->key);
232 print_name(m, class);
240 static const struct seq_operations lockdep_chains_ops = {
247 static int lockdep_chains_open(struct inode *inode, struct file *file)
249 int res = seq_open(file, &lockdep_chains_ops);
251 struct seq_file *m = file->private_data;
254 m->private = lock_chains;
261 static const struct file_operations proc_lockdep_chains_operations = {
262 .open = lockdep_chains_open,
265 .release = seq_release,
268 static void lockdep_stats_debug_show(struct seq_file *m)
270 #ifdef CONFIG_DEBUG_LOCKDEP
271 unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
272 hi2 = debug_atomic_read(&hardirqs_off_events),
273 hr1 = debug_atomic_read(&redundant_hardirqs_on),
274 hr2 = debug_atomic_read(&redundant_hardirqs_off),
275 si1 = debug_atomic_read(&softirqs_on_events),
276 si2 = debug_atomic_read(&softirqs_off_events),
277 sr1 = debug_atomic_read(&redundant_softirqs_on),
278 sr2 = debug_atomic_read(&redundant_softirqs_off);
280 seq_printf(m, " chain lookup misses: %11u\n",
281 debug_atomic_read(&chain_lookup_misses));
282 seq_printf(m, " chain lookup hits: %11u\n",
283 debug_atomic_read(&chain_lookup_hits));
284 seq_printf(m, " cyclic checks: %11u\n",
285 debug_atomic_read(&nr_cyclic_checks));
286 seq_printf(m, " cyclic-check recursions: %11u\n",
287 debug_atomic_read(&nr_cyclic_check_recursions));
288 seq_printf(m, " find-mask forwards checks: %11u\n",
289 debug_atomic_read(&nr_find_usage_forwards_checks));
290 seq_printf(m, " find-mask forwards recursions: %11u\n",
291 debug_atomic_read(&nr_find_usage_forwards_recursions));
292 seq_printf(m, " find-mask backwards checks: %11u\n",
293 debug_atomic_read(&nr_find_usage_backwards_checks));
294 seq_printf(m, " find-mask backwards recursions:%11u\n",
295 debug_atomic_read(&nr_find_usage_backwards_recursions));
297 seq_printf(m, " hardirq on events: %11u\n", hi1);
298 seq_printf(m, " hardirq off events: %11u\n", hi2);
299 seq_printf(m, " redundant hardirq ons: %11u\n", hr1);
300 seq_printf(m, " redundant hardirq offs: %11u\n", hr2);
301 seq_printf(m, " softirq on events: %11u\n", si1);
302 seq_printf(m, " softirq off events: %11u\n", si2);
303 seq_printf(m, " redundant softirq ons: %11u\n", sr1);
304 seq_printf(m, " redundant softirq offs: %11u\n", sr2);
308 static int lockdep_stats_show(struct seq_file *m, void *v)
310 struct lock_class *class;
311 unsigned long nr_unused = 0, nr_uncategorized = 0,
312 nr_irq_safe = 0, nr_irq_unsafe = 0,
313 nr_softirq_safe = 0, nr_softirq_unsafe = 0,
314 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
315 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
316 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
317 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
318 sum_forward_deps = 0, factor = 0;
320 list_for_each_entry(class, &all_lock_classes, lock_entry) {
322 if (class->usage_mask == 0)
324 if (class->usage_mask == LOCKF_USED)
326 if (class->usage_mask & LOCKF_USED_IN_IRQ)
328 if (class->usage_mask & LOCKF_ENABLED_IRQS)
330 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
332 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
334 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
336 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
338 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
340 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
341 nr_irq_read_unsafe++;
342 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
343 nr_softirq_read_safe++;
344 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
345 nr_softirq_read_unsafe++;
346 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
347 nr_hardirq_read_safe++;
348 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
349 nr_hardirq_read_unsafe++;
351 sum_forward_deps += count_forward_deps(class);
353 #ifdef CONFIG_DEBUG_LOCKDEP
354 DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
356 seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
357 nr_lock_classes, MAX_LOCKDEP_KEYS);
358 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
359 nr_list_entries, MAX_LOCKDEP_ENTRIES);
360 seq_printf(m, " indirect dependencies: %11lu\n",
364 * Total number of dependencies:
366 * All irq-safe locks may nest inside irq-unsafe locks,
367 * plus all the other known dependencies:
369 seq_printf(m, " all direct dependencies: %11lu\n",
370 nr_irq_unsafe * nr_irq_safe +
371 nr_hardirq_unsafe * nr_hardirq_safe +
375 * Estimated factor between direct and indirect
379 factor = sum_forward_deps / nr_list_entries;
381 #ifdef CONFIG_PROVE_LOCKING
382 seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
383 nr_lock_chains, MAX_LOCKDEP_CHAINS);
384 seq_printf(m, " dependency chain hlocks: %11d [max: %lu]\n",
385 atomic_read(&nr_chain_hlocks), MAX_LOCKDEP_CHAIN_HLOCKS);
388 #ifdef CONFIG_TRACE_IRQFLAGS
389 seq_printf(m, " in-hardirq chains: %11u\n",
391 seq_printf(m, " in-softirq chains: %11u\n",
394 seq_printf(m, " in-process chains: %11u\n",
396 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
397 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
398 seq_printf(m, " combined max dependencies: %11u\n",
399 (nr_hardirq_chains + 1) *
400 (nr_softirq_chains + 1) *
401 (nr_process_chains + 1)
403 seq_printf(m, " hardirq-safe locks: %11lu\n",
405 seq_printf(m, " hardirq-unsafe locks: %11lu\n",
407 seq_printf(m, " softirq-safe locks: %11lu\n",
409 seq_printf(m, " softirq-unsafe locks: %11lu\n",
411 seq_printf(m, " irq-safe locks: %11lu\n",
413 seq_printf(m, " irq-unsafe locks: %11lu\n",
416 seq_printf(m, " hardirq-read-safe locks: %11lu\n",
417 nr_hardirq_read_safe);
418 seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
419 nr_hardirq_read_unsafe);
420 seq_printf(m, " softirq-read-safe locks: %11lu\n",
421 nr_softirq_read_safe);
422 seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
423 nr_softirq_read_unsafe);
424 seq_printf(m, " irq-read-safe locks: %11lu\n",
426 seq_printf(m, " irq-read-unsafe locks: %11lu\n",
429 seq_printf(m, " uncategorized locks: %11lu\n",
431 seq_printf(m, " unused locks: %11lu\n",
433 seq_printf(m, " max locking depth: %11u\n",
435 seq_printf(m, " max recursion depth: %11u\n",
436 max_recursion_depth);
437 lockdep_stats_debug_show(m);
438 seq_printf(m, " debug_locks: %11u\n",
444 static int lockdep_stats_open(struct inode *inode, struct file *file)
446 return single_open(file, lockdep_stats_show, NULL);
449 static const struct file_operations proc_lockdep_stats_operations = {
450 .open = lockdep_stats_open,
453 .release = single_release,
456 #ifdef CONFIG_LOCK_STAT
458 struct lock_stat_data {
459 struct lock_class *class;
460 struct lock_class_stats stats;
463 struct lock_stat_seq {
464 struct lock_stat_data *iter;
465 struct lock_stat_data *iter_end;
466 struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
470 * sort on absolute number of contentions
472 static int lock_stat_cmp(const void *l, const void *r)
474 const struct lock_stat_data *dl = l, *dr = r;
475 unsigned long nl, nr;
477 nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
478 nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
483 static void seq_line(struct seq_file *m, char c, int offset, int length)
487 for (i = 0; i < offset; i++)
489 for (i = 0; i < length; i++)
490 seq_printf(m, "%c", c);
494 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
498 rem = do_div(nr, 1000); /* XXX: do_div_signed */
499 snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
502 static void seq_time(struct seq_file *m, s64 time)
506 snprint_time(num, sizeof(num), time);
507 seq_printf(m, " %14s", num);
510 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
512 seq_printf(m, "%14lu", lt->nr);
513 seq_time(m, lt->min);
514 seq_time(m, lt->max);
515 seq_time(m, lt->total);
518 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
521 struct lock_class *class;
522 struct lock_class_stats *stats;
526 stats = &data->stats;
529 if (class->name_version > 1)
530 namelen -= 2; /* XXX truncates versions > 9 */
535 char str[KSYM_NAME_LEN];
536 const char *key_name;
538 key_name = __get_key_name(class->key, str);
539 snprintf(name, namelen, "%s", key_name);
541 snprintf(name, namelen, "%s", class->name);
543 namelen = strlen(name);
544 if (class->name_version > 1) {
545 snprintf(name+namelen, 3, "#%d", class->name_version);
548 if (class->subclass) {
549 snprintf(name+namelen, 3, "/%d", class->subclass);
553 if (stats->write_holdtime.nr) {
554 if (stats->read_holdtime.nr)
555 seq_printf(m, "%38s-W:", name);
557 seq_printf(m, "%40s:", name);
559 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
560 seq_lock_time(m, &stats->write_waittime);
561 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
562 seq_lock_time(m, &stats->write_holdtime);
566 if (stats->read_holdtime.nr) {
567 seq_printf(m, "%38s-R:", name);
568 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
569 seq_lock_time(m, &stats->read_waittime);
570 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
571 seq_lock_time(m, &stats->read_holdtime);
575 if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
578 if (stats->read_holdtime.nr)
581 for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
582 char sym[KSYM_SYMBOL_LEN];
585 if (class->contention_point[i] == 0)
589 seq_line(m, '-', 40-namelen, namelen);
591 sprint_symbol(sym, class->contention_point[i]);
592 snprintf(ip, sizeof(ip), "[<%p>]",
593 (void *)class->contention_point[i]);
594 seq_printf(m, "%40s %14lu %29s %s\n", name,
595 stats->contention_point[i],
600 seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
605 static void seq_header(struct seq_file *m)
607 seq_printf(m, "lock_stat version 0.2\n");
608 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
609 seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
622 seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
626 static void *ls_start(struct seq_file *m, loff_t *pos)
628 struct lock_stat_seq *data = m->private;
631 return SEQ_START_TOKEN;
633 data->iter = data->stats + *pos;
634 if (data->iter >= data->iter_end)
640 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
642 struct lock_stat_seq *data = m->private;
646 if (v == SEQ_START_TOKEN)
647 data->iter = data->stats;
653 if (data->iter == data->iter_end)
659 static void ls_stop(struct seq_file *m, void *v)
663 static int ls_show(struct seq_file *m, void *v)
665 if (v == SEQ_START_TOKEN)
673 static struct seq_operations lockstat_ops = {
680 static int lock_stat_open(struct inode *inode, struct file *file)
683 struct lock_class *class;
684 struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
689 res = seq_open(file, &lockstat_ops);
691 struct lock_stat_data *iter = data->stats;
692 struct seq_file *m = file->private_data;
695 list_for_each_entry(class, &all_lock_classes, lock_entry) {
697 iter->stats = lock_stats(class);
700 data->iter_end = iter;
702 sort(data->stats, data->iter_end - data->iter,
703 sizeof(struct lock_stat_data),
704 lock_stat_cmp, NULL);
713 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
714 size_t count, loff_t *ppos)
716 struct lock_class *class;
720 if (get_user(c, buf))
726 list_for_each_entry(class, &all_lock_classes, lock_entry)
727 clear_lock_stats(class);
732 static int lock_stat_release(struct inode *inode, struct file *file)
734 struct seq_file *seq = file->private_data;
738 return seq_release(inode, file);
741 static const struct file_operations proc_lock_stat_operations = {
742 .open = lock_stat_open,
743 .write = lock_stat_write,
746 .release = lock_stat_release,
748 #endif /* CONFIG_LOCK_STAT */
750 static int __init lockdep_proc_init(void)
752 proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
753 proc_create("lockdep_chains", S_IRUSR, NULL,
754 &proc_lockdep_chains_operations);
755 proc_create("lockdep_stats", S_IRUSR, NULL,
756 &proc_lockdep_stats_operations);
758 #ifdef CONFIG_LOCK_STAT
759 proc_create("lock_stat", S_IRUSR, NULL, &proc_lock_stat_operations);
765 __initcall(lockdep_proc_init);