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);
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 lockdep_stats_debug_show(struct seq_file
*m
)
183 #ifdef CONFIG_DEBUG_LOCKDEP
184 unsigned int hi1
= debug_atomic_read(&hardirqs_on_events
),
185 hi2
= debug_atomic_read(&hardirqs_off_events
),
186 hr1
= debug_atomic_read(&redundant_hardirqs_on
),
187 hr2
= debug_atomic_read(&redundant_hardirqs_off
),
188 si1
= debug_atomic_read(&softirqs_on_events
),
189 si2
= debug_atomic_read(&softirqs_off_events
),
190 sr1
= debug_atomic_read(&redundant_softirqs_on
),
191 sr2
= debug_atomic_read(&redundant_softirqs_off
);
193 seq_printf(m
, " chain lookup misses: %11u\n",
194 debug_atomic_read(&chain_lookup_misses
));
195 seq_printf(m
, " chain lookup hits: %11u\n",
196 debug_atomic_read(&chain_lookup_hits
));
197 seq_printf(m
, " cyclic checks: %11u\n",
198 debug_atomic_read(&nr_cyclic_checks
));
199 seq_printf(m
, " cyclic-check recursions: %11u\n",
200 debug_atomic_read(&nr_cyclic_check_recursions
));
201 seq_printf(m
, " find-mask forwards checks: %11u\n",
202 debug_atomic_read(&nr_find_usage_forwards_checks
));
203 seq_printf(m
, " find-mask forwards recursions: %11u\n",
204 debug_atomic_read(&nr_find_usage_forwards_recursions
));
205 seq_printf(m
, " find-mask backwards checks: %11u\n",
206 debug_atomic_read(&nr_find_usage_backwards_checks
));
207 seq_printf(m
, " find-mask backwards recursions:%11u\n",
208 debug_atomic_read(&nr_find_usage_backwards_recursions
));
210 seq_printf(m
, " hardirq on events: %11u\n", hi1
);
211 seq_printf(m
, " hardirq off events: %11u\n", hi2
);
212 seq_printf(m
, " redundant hardirq ons: %11u\n", hr1
);
213 seq_printf(m
, " redundant hardirq offs: %11u\n", hr2
);
214 seq_printf(m
, " softirq on events: %11u\n", si1
);
215 seq_printf(m
, " softirq off events: %11u\n", si2
);
216 seq_printf(m
, " redundant softirq ons: %11u\n", sr1
);
217 seq_printf(m
, " redundant softirq offs: %11u\n", sr2
);
221 static int lockdep_stats_show(struct seq_file
*m
, void *v
)
223 struct lock_class
*class;
224 unsigned long nr_unused
= 0, nr_uncategorized
= 0,
225 nr_irq_safe
= 0, nr_irq_unsafe
= 0,
226 nr_softirq_safe
= 0, nr_softirq_unsafe
= 0,
227 nr_hardirq_safe
= 0, nr_hardirq_unsafe
= 0,
228 nr_irq_read_safe
= 0, nr_irq_read_unsafe
= 0,
229 nr_softirq_read_safe
= 0, nr_softirq_read_unsafe
= 0,
230 nr_hardirq_read_safe
= 0, nr_hardirq_read_unsafe
= 0,
231 sum_forward_deps
= 0, factor
= 0;
233 list_for_each_entry(class, &all_lock_classes
, lock_entry
) {
235 if (class->usage_mask
== 0)
237 if (class->usage_mask
== LOCKF_USED
)
239 if (class->usage_mask
& LOCKF_USED_IN_IRQ
)
241 if (class->usage_mask
& LOCKF_ENABLED_IRQS
)
243 if (class->usage_mask
& LOCKF_USED_IN_SOFTIRQ
)
245 if (class->usage_mask
& LOCKF_ENABLED_SOFTIRQS
)
247 if (class->usage_mask
& LOCKF_USED_IN_HARDIRQ
)
249 if (class->usage_mask
& LOCKF_ENABLED_HARDIRQS
)
251 if (class->usage_mask
& LOCKF_USED_IN_IRQ_READ
)
253 if (class->usage_mask
& LOCKF_ENABLED_IRQS_READ
)
254 nr_irq_read_unsafe
++;
255 if (class->usage_mask
& LOCKF_USED_IN_SOFTIRQ_READ
)
256 nr_softirq_read_safe
++;
257 if (class->usage_mask
& LOCKF_ENABLED_SOFTIRQS_READ
)
258 nr_softirq_read_unsafe
++;
259 if (class->usage_mask
& LOCKF_USED_IN_HARDIRQ_READ
)
260 nr_hardirq_read_safe
++;
261 if (class->usage_mask
& LOCKF_ENABLED_HARDIRQS_READ
)
262 nr_hardirq_read_unsafe
++;
264 sum_forward_deps
+= count_forward_deps(class);
266 #ifdef CONFIG_DEBUG_LOCKDEP
267 DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks
) != nr_unused
);
269 seq_printf(m
, " lock-classes: %11lu [max: %lu]\n",
270 nr_lock_classes
, MAX_LOCKDEP_KEYS
);
271 seq_printf(m
, " direct dependencies: %11lu [max: %lu]\n",
272 nr_list_entries
, MAX_LOCKDEP_ENTRIES
);
273 seq_printf(m
, " indirect dependencies: %11lu\n",
277 * Total number of dependencies:
279 * All irq-safe locks may nest inside irq-unsafe locks,
280 * plus all the other known dependencies:
282 seq_printf(m
, " all direct dependencies: %11lu\n",
283 nr_irq_unsafe
* nr_irq_safe
+
284 nr_hardirq_unsafe
* nr_hardirq_safe
+
288 * Estimated factor between direct and indirect
292 factor
= sum_forward_deps
/ nr_list_entries
;
294 #ifdef CONFIG_PROVE_LOCKING
295 seq_printf(m
, " dependency chains: %11lu [max: %lu]\n",
296 nr_lock_chains
, MAX_LOCKDEP_CHAINS
);
299 #ifdef CONFIG_TRACE_IRQFLAGS
300 seq_printf(m
, " in-hardirq chains: %11u\n",
302 seq_printf(m
, " in-softirq chains: %11u\n",
305 seq_printf(m
, " in-process chains: %11u\n",
307 seq_printf(m
, " stack-trace entries: %11lu [max: %lu]\n",
308 nr_stack_trace_entries
, MAX_STACK_TRACE_ENTRIES
);
309 seq_printf(m
, " combined max dependencies: %11u\n",
310 (nr_hardirq_chains
+ 1) *
311 (nr_softirq_chains
+ 1) *
312 (nr_process_chains
+ 1)
314 seq_printf(m
, " hardirq-safe locks: %11lu\n",
316 seq_printf(m
, " hardirq-unsafe locks: %11lu\n",
318 seq_printf(m
, " softirq-safe locks: %11lu\n",
320 seq_printf(m
, " softirq-unsafe locks: %11lu\n",
322 seq_printf(m
, " irq-safe locks: %11lu\n",
324 seq_printf(m
, " irq-unsafe locks: %11lu\n",
327 seq_printf(m
, " hardirq-read-safe locks: %11lu\n",
328 nr_hardirq_read_safe
);
329 seq_printf(m
, " hardirq-read-unsafe locks: %11lu\n",
330 nr_hardirq_read_unsafe
);
331 seq_printf(m
, " softirq-read-safe locks: %11lu\n",
332 nr_softirq_read_safe
);
333 seq_printf(m
, " softirq-read-unsafe locks: %11lu\n",
334 nr_softirq_read_unsafe
);
335 seq_printf(m
, " irq-read-safe locks: %11lu\n",
337 seq_printf(m
, " irq-read-unsafe locks: %11lu\n",
340 seq_printf(m
, " uncategorized locks: %11lu\n",
342 seq_printf(m
, " unused locks: %11lu\n",
344 seq_printf(m
, " max locking depth: %11u\n",
346 seq_printf(m
, " max recursion depth: %11u\n",
347 max_recursion_depth
);
348 lockdep_stats_debug_show(m
);
349 seq_printf(m
, " debug_locks: %11u\n",
355 static int lockdep_stats_open(struct inode
*inode
, struct file
*file
)
357 return single_open(file
, lockdep_stats_show
, NULL
);
360 static const struct file_operations proc_lockdep_stats_operations
= {
361 .open
= lockdep_stats_open
,
364 .release
= single_release
,
367 #ifdef CONFIG_LOCK_STAT
369 struct lock_stat_data
{
370 struct lock_class
*class;
371 struct lock_class_stats stats
;
374 struct lock_stat_seq
{
375 struct lock_stat_data
*iter
;
376 struct lock_stat_data
*iter_end
;
377 struct lock_stat_data stats
[MAX_LOCKDEP_KEYS
];
381 * sort on absolute number of contentions
383 static int lock_stat_cmp(const void *l
, const void *r
)
385 const struct lock_stat_data
*dl
= l
, *dr
= r
;
386 unsigned long nl
, nr
;
388 nl
= dl
->stats
.read_waittime
.nr
+ dl
->stats
.write_waittime
.nr
;
389 nr
= dr
->stats
.read_waittime
.nr
+ dr
->stats
.write_waittime
.nr
;
394 static void seq_line(struct seq_file
*m
, char c
, int offset
, int length
)
398 for (i
= 0; i
< offset
; i
++)
400 for (i
= 0; i
< length
; i
++)
401 seq_printf(m
, "%c", c
);
405 static void snprint_time(char *buf
, size_t bufsiz
, s64 nr
)
409 rem
= do_div(nr
, 1000); /* XXX: do_div_signed */
410 snprintf(buf
, bufsiz
, "%lld.%02d", (long long)nr
, ((int)rem
+5)/10);
413 static void seq_time(struct seq_file
*m
, s64 time
)
417 snprint_time(num
, sizeof(num
), time
);
418 seq_printf(m
, " %14s", num
);
421 static void seq_lock_time(struct seq_file
*m
, struct lock_time
*lt
)
423 seq_printf(m
, "%14lu", lt
->nr
);
424 seq_time(m
, lt
->min
);
425 seq_time(m
, lt
->max
);
426 seq_time(m
, lt
->total
);
429 static void seq_stats(struct seq_file
*m
, struct lock_stat_data
*data
)
432 struct lock_class
*class;
433 struct lock_class_stats
*stats
;
437 stats
= &data
->stats
;
440 if (class->name_version
> 1)
441 namelen
-= 2; /* XXX truncates versions > 9 */
446 char str
[KSYM_NAME_LEN
];
447 const char *key_name
;
449 key_name
= __get_key_name(class->key
, str
);
450 snprintf(name
, namelen
, "%s", key_name
);
452 snprintf(name
, namelen
, "%s", class->name
);
454 namelen
= strlen(name
);
455 if (class->name_version
> 1) {
456 snprintf(name
+namelen
, 3, "#%d", class->name_version
);
459 if (class->subclass
) {
460 snprintf(name
+namelen
, 3, "/%d", class->subclass
);
464 if (stats
->write_holdtime
.nr
) {
465 if (stats
->read_holdtime
.nr
)
466 seq_printf(m
, "%38s-W:", name
);
468 seq_printf(m
, "%40s:", name
);
470 seq_printf(m
, "%14lu ", stats
->bounces
[bounce_contended_write
]);
471 seq_lock_time(m
, &stats
->write_waittime
);
472 seq_printf(m
, " %14lu ", stats
->bounces
[bounce_acquired_write
]);
473 seq_lock_time(m
, &stats
->write_holdtime
);
477 if (stats
->read_holdtime
.nr
) {
478 seq_printf(m
, "%38s-R:", name
);
479 seq_printf(m
, "%14lu ", stats
->bounces
[bounce_contended_read
]);
480 seq_lock_time(m
, &stats
->read_waittime
);
481 seq_printf(m
, " %14lu ", stats
->bounces
[bounce_acquired_read
]);
482 seq_lock_time(m
, &stats
->read_holdtime
);
486 if (stats
->read_waittime
.nr
+ stats
->write_waittime
.nr
== 0)
489 if (stats
->read_holdtime
.nr
)
492 for (i
= 0; i
< ARRAY_SIZE(class->contention_point
); i
++) {
493 char sym
[KSYM_SYMBOL_LEN
];
496 if (class->contention_point
[i
] == 0)
500 seq_line(m
, '-', 40-namelen
, namelen
);
502 sprint_symbol(sym
, class->contention_point
[i
]);
503 snprintf(ip
, sizeof(ip
), "[<%p>]",
504 (void *)class->contention_point
[i
]);
505 seq_printf(m
, "%40s %14lu %29s %s\n", name
,
506 stats
->contention_point
[i
],
511 seq_line(m
, '.', 0, 40 + 1 + 10 * (14 + 1));
516 static void seq_header(struct seq_file
*m
)
518 seq_printf(m
, "lock_stat version 0.2\n");
519 seq_line(m
, '-', 0, 40 + 1 + 10 * (14 + 1));
520 seq_printf(m
, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
533 seq_line(m
, '-', 0, 40 + 1 + 10 * (14 + 1));
537 static void *ls_start(struct seq_file
*m
, loff_t
*pos
)
539 struct lock_stat_seq
*data
= m
->private;
542 return SEQ_START_TOKEN
;
544 data
->iter
= data
->stats
+ *pos
;
545 if (data
->iter
>= data
->iter_end
)
551 static void *ls_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
553 struct lock_stat_seq
*data
= m
->private;
557 if (v
== SEQ_START_TOKEN
)
558 data
->iter
= data
->stats
;
564 if (data
->iter
== data
->iter_end
)
570 static void ls_stop(struct seq_file
*m
, void *v
)
574 static int ls_show(struct seq_file
*m
, void *v
)
576 if (v
== SEQ_START_TOKEN
)
584 static struct seq_operations lockstat_ops
= {
591 static int lock_stat_open(struct inode
*inode
, struct file
*file
)
594 struct lock_class
*class;
595 struct lock_stat_seq
*data
= vmalloc(sizeof(struct lock_stat_seq
));
600 res
= seq_open(file
, &lockstat_ops
);
602 struct lock_stat_data
*iter
= data
->stats
;
603 struct seq_file
*m
= file
->private_data
;
606 list_for_each_entry(class, &all_lock_classes
, lock_entry
) {
608 iter
->stats
= lock_stats(class);
611 data
->iter_end
= iter
;
613 sort(data
->stats
, data
->iter_end
- data
->iter
,
614 sizeof(struct lock_stat_data
),
615 lock_stat_cmp
, NULL
);
624 static ssize_t
lock_stat_write(struct file
*file
, const char __user
*buf
,
625 size_t count
, loff_t
*ppos
)
627 struct lock_class
*class;
631 if (get_user(c
, buf
))
637 list_for_each_entry(class, &all_lock_classes
, lock_entry
)
638 clear_lock_stats(class);
643 static int lock_stat_release(struct inode
*inode
, struct file
*file
)
645 struct seq_file
*seq
= file
->private_data
;
649 return seq_release(inode
, file
);
652 static const struct file_operations proc_lock_stat_operations
= {
653 .open
= lock_stat_open
,
654 .write
= lock_stat_write
,
657 .release
= lock_stat_release
,
659 #endif /* CONFIG_LOCK_STAT */
661 static int __init
lockdep_proc_init(void)
663 proc_create("lockdep", S_IRUSR
, NULL
, &proc_lockdep_operations
);
664 proc_create("lockdep_stats", S_IRUSR
, NULL
,
665 &proc_lockdep_stats_operations
);
667 #ifdef CONFIG_LOCK_STAT
668 proc_create("lock_stat", S_IRUSR
, NULL
, &proc_lock_stat_operations
);
674 __initcall(lockdep_proc_init
);