1 // SPDX-License-Identifier: GPL-2.0
3 * kernel/lockdep_proc.c
5 * Runtime locking correctness validator
7 * Started by Ingo Molnar:
9 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
10 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
12 * Code for /proc/lockdep and /proc/lockdep_stats:
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>
25 #include "lockdep_internals.h"
27 static void *l_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
29 return seq_list_next(v
, &all_lock_classes
, pos
);
32 static void *l_start(struct seq_file
*m
, loff_t
*pos
)
34 return seq_list_start_head(&all_lock_classes
, *pos
);
37 static void l_stop(struct seq_file
*m
, void *v
)
41 static void print_name(struct seq_file
*m
, struct lock_class
*class)
43 char str
[KSYM_NAME_LEN
];
44 const char *name
= class->name
;
47 name
= __get_key_name(class->key
, str
);
48 seq_printf(m
, "%s", name
);
50 seq_printf(m
, "%s", name
);
51 if (class->name_version
> 1)
52 seq_printf(m
, "#%d", class->name_version
);
54 seq_printf(m
, "/%d", class->subclass
);
58 static int l_show(struct seq_file
*m
, void *v
)
60 struct lock_class
*class = list_entry(v
, struct lock_class
, lock_entry
);
61 struct lock_list
*entry
;
62 char usage
[LOCK_USAGE_CHARS
];
64 if (v
== &all_lock_classes
) {
65 seq_printf(m
, "all lock classes:\n");
69 seq_printf(m
, "%p", class->key
);
70 #ifdef CONFIG_DEBUG_LOCKDEP
71 seq_printf(m
, " OPS:%8ld", class->ops
);
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));
78 get_usage_chars(class, usage
);
79 seq_printf(m
, " %s", usage
);
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);
97 static const struct seq_operations lockdep_ops
= {
104 static int lockdep_open(struct inode
*inode
, struct file
*file
)
106 return seq_open(file
, &lockdep_ops
);
109 static const struct file_operations proc_lockdep_operations
= {
110 .open
= lockdep_open
,
113 .release
= seq_release
,
116 #ifdef CONFIG_PROVE_LOCKING
117 static void *lc_start(struct seq_file
*m
, loff_t
*pos
)
120 return SEQ_START_TOKEN
;
122 if (*pos
- 1 < nr_lock_chains
)
123 return lock_chains
+ (*pos
- 1);
128 static void *lc_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
131 return lc_start(m
, pos
);
134 static void lc_stop(struct seq_file
*m
, void *v
)
138 static int lc_show(struct seq_file
*m
, void *v
)
140 struct lock_chain
*chain
= v
;
141 struct lock_class
*class;
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");
151 seq_printf(m
, "irq_context: %d\n", chain
->irq_context
);
153 for (i
= 0; i
< chain
->depth
; i
++) {
154 class = lock_chain_get_class(chain
, i
);
158 seq_printf(m
, "[%p] ", class->key
);
159 print_name(m
, class);
167 static const struct seq_operations lockdep_chains_ops
= {
174 static int lockdep_chains_open(struct inode
*inode
, struct file
*file
)
176 return seq_open(file
, &lockdep_chains_ops
);
179 static const struct file_operations proc_lockdep_chains_operations
= {
180 .open
= lockdep_chains_open
,
183 .release
= seq_release
,
185 #endif /* CONFIG_PROVE_LOCKING */
187 static void lockdep_stats_debug_show(struct seq_file
*m
)
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
);
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
));
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
);
225 static int lockdep_stats_show(struct seq_file
*m
, void *v
)
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;
237 list_for_each_entry(class, &all_lock_classes
, lock_entry
) {
239 if (class->usage_mask
== 0)
241 if (class->usage_mask
== LOCKF_USED
)
243 if (class->usage_mask
& LOCKF_USED_IN_IRQ
)
245 if (class->usage_mask
& LOCKF_ENABLED_IRQ
)
247 if (class->usage_mask
& LOCKF_USED_IN_SOFTIRQ
)
249 if (class->usage_mask
& LOCKF_ENABLED_SOFTIRQ
)
251 if (class->usage_mask
& LOCKF_USED_IN_HARDIRQ
)
253 if (class->usage_mask
& LOCKF_ENABLED_HARDIRQ
)
255 if (class->usage_mask
& LOCKF_USED_IN_IRQ_READ
)
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
++;
268 #ifdef CONFIG_PROVE_LOCKING
269 sum_forward_deps
+= lockdep_count_forward_deps(class);
272 #ifdef CONFIG_DEBUG_LOCKDEP
273 DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks
) != nr_unused
);
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",
283 * Total number of dependencies:
285 * All irq-safe locks may nest inside irq-unsafe locks,
286 * plus all the other known dependencies:
288 seq_printf(m
, " all direct dependencies: %11lu\n",
289 nr_irq_unsafe
* nr_irq_safe
+
290 nr_hardirq_unsafe
* nr_hardirq_safe
+
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
);
300 #ifdef CONFIG_TRACE_IRQFLAGS
301 seq_printf(m
, " in-hardirq chains: %11u\n",
303 seq_printf(m
, " in-softirq chains: %11u\n",
306 seq_printf(m
, " in-process chains: %11u\n",
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)
315 seq_printf(m
, " hardirq-safe locks: %11lu\n",
317 seq_printf(m
, " hardirq-unsafe locks: %11lu\n",
319 seq_printf(m
, " softirq-safe locks: %11lu\n",
321 seq_printf(m
, " softirq-unsafe locks: %11lu\n",
323 seq_printf(m
, " irq-safe locks: %11lu\n",
325 seq_printf(m
, " irq-unsafe locks: %11lu\n",
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",
338 seq_printf(m
, " irq-read-unsafe locks: %11lu\n",
341 seq_printf(m
, " uncategorized locks: %11lu\n",
343 seq_printf(m
, " unused locks: %11lu\n",
345 seq_printf(m
, " max locking depth: %11u\n",
347 #ifdef CONFIG_PROVE_LOCKING
348 seq_printf(m
, " max bfs queue depth: %11u\n",
349 max_bfs_queue_depth
);
351 lockdep_stats_debug_show(m
);
352 seq_printf(m
, " debug_locks: %11u\n",
358 static int lockdep_stats_open(struct inode
*inode
, struct file
*file
)
360 return single_open(file
, lockdep_stats_show
, NULL
);
363 static const struct file_operations proc_lockdep_stats_operations
= {
364 .open
= lockdep_stats_open
,
367 .release
= single_release
,
370 #ifdef CONFIG_LOCK_STAT
372 struct lock_stat_data
{
373 struct lock_class
*class;
374 struct lock_class_stats stats
;
377 struct lock_stat_seq
{
378 struct lock_stat_data
*iter_end
;
379 struct lock_stat_data stats
[MAX_LOCKDEP_KEYS
];
383 * sort on absolute number of contentions
385 static int lock_stat_cmp(const void *l
, const void *r
)
387 const struct lock_stat_data
*dl
= l
, *dr
= r
;
388 unsigned long nl
, nr
;
390 nl
= dl
->stats
.read_waittime
.nr
+ dl
->stats
.write_waittime
.nr
;
391 nr
= dr
->stats
.read_waittime
.nr
+ dr
->stats
.write_waittime
.nr
;
396 static void seq_line(struct seq_file
*m
, char c
, int offset
, int length
)
400 for (i
= 0; i
< offset
; i
++)
402 for (i
= 0; i
< length
; i
++)
403 seq_printf(m
, "%c", c
);
407 static void snprint_time(char *buf
, size_t bufsiz
, s64 nr
)
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);
417 static void seq_time(struct seq_file
*m
, s64 time
)
421 snprint_time(num
, sizeof(num
), time
);
422 seq_printf(m
, " %14s", num
);
425 static void seq_lock_time(struct seq_file
*m
, struct lock_time
*lt
)
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);
434 static void seq_stats(struct seq_file
*m
, struct lock_stat_data
*data
)
436 struct lockdep_subclass_key
*ckey
;
437 struct lock_class_stats
*stats
;
438 struct lock_class
*class;
444 stats
= &data
->stats
;
447 if (class->name_version
> 1)
448 namelen
-= 2; /* XXX truncates versions > 9 */
452 rcu_read_lock_sched();
453 cname
= rcu_dereference_sched(class->name
);
454 ckey
= rcu_dereference_sched(class->key
);
456 if (!cname
&& !ckey
) {
457 rcu_read_unlock_sched();
461 char str
[KSYM_NAME_LEN
];
462 const char *key_name
;
464 key_name
= __get_key_name(ckey
, str
);
465 snprintf(name
, namelen
, "%s", key_name
);
467 snprintf(name
, namelen
, "%s", cname
);
469 rcu_read_unlock_sched();
471 namelen
= strlen(name
);
472 if (class->name_version
> 1) {
473 snprintf(name
+namelen
, 3, "#%d", class->name_version
);
476 if (class->subclass
) {
477 snprintf(name
+namelen
, 3, "/%d", class->subclass
);
481 if (stats
->write_holdtime
.nr
) {
482 if (stats
->read_holdtime
.nr
)
483 seq_printf(m
, "%38s-W:", name
);
485 seq_printf(m
, "%40s:", name
);
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
);
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
);
503 if (stats
->read_waittime
.nr
+ stats
->write_waittime
.nr
== 0)
506 if (stats
->read_holdtime
.nr
)
509 for (i
= 0; i
< LOCKSTAT_POINTS
; i
++) {
512 if (class->contention_point
[i
] == 0)
516 seq_line(m
, '-', 40-namelen
, namelen
);
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
]);
524 for (i
= 0; i
< LOCKSTAT_POINTS
; i
++) {
527 if (class->contending_point
[i
] == 0)
531 seq_line(m
, '-', 40-namelen
, namelen
);
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
]);
541 seq_line(m
, '.', 0, 40 + 1 + 12 * (14 + 1));
546 static void seq_header(struct seq_file
*m
)
548 seq_puts(m
, "lock_stat version 0.4\n");
550 if (unlikely(!debug_locks
))
551 seq_printf(m
, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
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 "
569 seq_line(m
, '-', 0, 40 + 1 + 12 * (14 + 1));
573 static void *ls_start(struct seq_file
*m
, loff_t
*pos
)
575 struct lock_stat_seq
*data
= m
->private;
576 struct lock_stat_data
*iter
;
579 return SEQ_START_TOKEN
;
581 iter
= data
->stats
+ (*pos
- 1);
582 if (iter
>= data
->iter_end
)
588 static void *ls_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
591 return ls_start(m
, pos
);
594 static void ls_stop(struct seq_file
*m
, void *v
)
598 static int ls_show(struct seq_file
*m
, void *v
)
600 if (v
== SEQ_START_TOKEN
)
608 static const struct seq_operations lockstat_ops
= {
615 static int lock_stat_open(struct inode
*inode
, struct file
*file
)
618 struct lock_class
*class;
619 struct lock_stat_seq
*data
= vmalloc(sizeof(struct lock_stat_seq
));
624 res
= seq_open(file
, &lockstat_ops
);
626 struct lock_stat_data
*iter
= data
->stats
;
627 struct seq_file
*m
= file
->private_data
;
629 list_for_each_entry(class, &all_lock_classes
, lock_entry
) {
631 iter
->stats
= lock_stats(class);
634 data
->iter_end
= iter
;
636 sort(data
->stats
, data
->iter_end
- data
->stats
,
637 sizeof(struct lock_stat_data
),
638 lock_stat_cmp
, NULL
);
647 static ssize_t
lock_stat_write(struct file
*file
, const char __user
*buf
,
648 size_t count
, loff_t
*ppos
)
650 struct lock_class
*class;
654 if (get_user(c
, buf
))
660 list_for_each_entry(class, &all_lock_classes
, lock_entry
)
661 clear_lock_stats(class);
666 static int lock_stat_release(struct inode
*inode
, struct file
*file
)
668 struct seq_file
*seq
= file
->private_data
;
671 return seq_release(inode
, file
);
674 static const struct file_operations proc_lock_stat_operations
= {
675 .open
= lock_stat_open
,
676 .write
= lock_stat_write
,
679 .release
= lock_stat_release
,
681 #endif /* CONFIG_LOCK_STAT */
683 static int __init
lockdep_proc_init(void)
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
);
690 proc_create("lockdep_stats", S_IRUSR
, NULL
,
691 &proc_lockdep_stats_operations
);
693 #ifdef CONFIG_LOCK_STAT
694 proc_create("lock_stat", S_IRUSR
| S_IWUSR
, NULL
,
695 &proc_lock_stat_operations
);
701 __initcall(lockdep_proc_init
);