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 = v
;
32 if (class->lock_entry
.next
!= &all_lock_classes
)
33 class = list_entry(class->lock_entry
.next
, struct lock_class
,
42 static void *l_start(struct seq_file
*m
, loff_t
*pos
)
44 struct lock_class
*class = m
->private;
46 if (&class->lock_entry
== all_lock_classes
.next
)
47 seq_printf(m
, "all lock classes:\n");
52 static void l_stop(struct seq_file
*m
, void *v
)
56 static unsigned long count_forward_deps(struct lock_class
*class)
58 struct lock_list
*entry
;
59 unsigned long ret
= 1;
62 * Recurse this class's dependency list:
64 list_for_each_entry(entry
, &class->locks_after
, entry
)
65 ret
+= count_forward_deps(entry
->class);
70 static unsigned long count_backward_deps(struct lock_class
*class)
72 struct lock_list
*entry
;
73 unsigned long ret
= 1;
76 * Recurse this class's dependency list:
78 list_for_each_entry(entry
, &class->locks_before
, entry
)
79 ret
+= count_backward_deps(entry
->class);
84 static void print_name(struct seq_file
*m
, struct lock_class
*class)
87 const char *name
= class->name
;
90 name
= __get_key_name(class->key
, str
);
91 seq_printf(m
, "%s", name
);
93 seq_printf(m
, "%s", name
);
94 if (class->name_version
> 1)
95 seq_printf(m
, "#%d", class->name_version
);
97 seq_printf(m
, "/%d", class->subclass
);
101 static int l_show(struct seq_file
*m
, void *v
)
103 unsigned long nr_forward_deps
, nr_backward_deps
;
104 struct lock_class
*class = m
->private;
105 struct lock_list
*entry
;
108 seq_printf(m
, "%p", class->key
);
109 #ifdef CONFIG_DEBUG_LOCKDEP
110 seq_printf(m
, " OPS:%8ld", class->ops
);
112 nr_forward_deps
= count_forward_deps(class);
113 seq_printf(m
, " FD:%5ld", nr_forward_deps
);
115 nr_backward_deps
= count_backward_deps(class);
116 seq_printf(m
, " BD:%5ld", nr_backward_deps
);
118 get_usage_chars(class, &c1
, &c2
, &c3
, &c4
);
119 seq_printf(m
, " %c%c%c%c", c1
, c2
, c3
, c4
);
122 print_name(m
, class);
125 list_for_each_entry(entry
, &class->locks_after
, entry
) {
126 if (entry
->distance
== 1) {
127 seq_printf(m
, " -> [%p] ", entry
->class);
128 print_name(m
, entry
->class);
137 static const struct seq_operations lockdep_ops
= {
144 static int lockdep_open(struct inode
*inode
, struct file
*file
)
146 int res
= seq_open(file
, &lockdep_ops
);
148 struct seq_file
*m
= file
->private_data
;
150 if (!list_empty(&all_lock_classes
))
151 m
->private = list_entry(all_lock_classes
.next
,
152 struct lock_class
, lock_entry
);
159 static const struct file_operations proc_lockdep_operations
= {
160 .open
= lockdep_open
,
163 .release
= seq_release
,
166 static void lockdep_stats_debug_show(struct seq_file
*m
)
168 #ifdef CONFIG_DEBUG_LOCKDEP
169 unsigned int hi1
= debug_atomic_read(&hardirqs_on_events
),
170 hi2
= debug_atomic_read(&hardirqs_off_events
),
171 hr1
= debug_atomic_read(&redundant_hardirqs_on
),
172 hr2
= debug_atomic_read(&redundant_hardirqs_off
),
173 si1
= debug_atomic_read(&softirqs_on_events
),
174 si2
= debug_atomic_read(&softirqs_off_events
),
175 sr1
= debug_atomic_read(&redundant_softirqs_on
),
176 sr2
= debug_atomic_read(&redundant_softirqs_off
);
178 seq_printf(m
, " chain lookup misses: %11u\n",
179 debug_atomic_read(&chain_lookup_misses
));
180 seq_printf(m
, " chain lookup hits: %11u\n",
181 debug_atomic_read(&chain_lookup_hits
));
182 seq_printf(m
, " cyclic checks: %11u\n",
183 debug_atomic_read(&nr_cyclic_checks
));
184 seq_printf(m
, " cyclic-check recursions: %11u\n",
185 debug_atomic_read(&nr_cyclic_check_recursions
));
186 seq_printf(m
, " find-mask forwards checks: %11u\n",
187 debug_atomic_read(&nr_find_usage_forwards_checks
));
188 seq_printf(m
, " find-mask forwards recursions: %11u\n",
189 debug_atomic_read(&nr_find_usage_forwards_recursions
));
190 seq_printf(m
, " find-mask backwards checks: %11u\n",
191 debug_atomic_read(&nr_find_usage_backwards_checks
));
192 seq_printf(m
, " find-mask backwards recursions:%11u\n",
193 debug_atomic_read(&nr_find_usage_backwards_recursions
));
195 seq_printf(m
, " hardirq on events: %11u\n", hi1
);
196 seq_printf(m
, " hardirq off events: %11u\n", hi2
);
197 seq_printf(m
, " redundant hardirq ons: %11u\n", hr1
);
198 seq_printf(m
, " redundant hardirq offs: %11u\n", hr2
);
199 seq_printf(m
, " softirq on events: %11u\n", si1
);
200 seq_printf(m
, " softirq off events: %11u\n", si2
);
201 seq_printf(m
, " redundant softirq ons: %11u\n", sr1
);
202 seq_printf(m
, " redundant softirq offs: %11u\n", sr2
);
206 static int lockdep_stats_show(struct seq_file
*m
, void *v
)
208 struct lock_class
*class;
209 unsigned long nr_unused
= 0, nr_uncategorized
= 0,
210 nr_irq_safe
= 0, nr_irq_unsafe
= 0,
211 nr_softirq_safe
= 0, nr_softirq_unsafe
= 0,
212 nr_hardirq_safe
= 0, nr_hardirq_unsafe
= 0,
213 nr_irq_read_safe
= 0, nr_irq_read_unsafe
= 0,
214 nr_softirq_read_safe
= 0, nr_softirq_read_unsafe
= 0,
215 nr_hardirq_read_safe
= 0, nr_hardirq_read_unsafe
= 0,
216 sum_forward_deps
= 0, factor
= 0;
218 list_for_each_entry(class, &all_lock_classes
, lock_entry
) {
220 if (class->usage_mask
== 0)
222 if (class->usage_mask
== LOCKF_USED
)
224 if (class->usage_mask
& LOCKF_USED_IN_IRQ
)
226 if (class->usage_mask
& LOCKF_ENABLED_IRQS
)
228 if (class->usage_mask
& LOCKF_USED_IN_SOFTIRQ
)
230 if (class->usage_mask
& LOCKF_ENABLED_SOFTIRQS
)
232 if (class->usage_mask
& LOCKF_USED_IN_HARDIRQ
)
234 if (class->usage_mask
& LOCKF_ENABLED_HARDIRQS
)
236 if (class->usage_mask
& LOCKF_USED_IN_IRQ_READ
)
238 if (class->usage_mask
& LOCKF_ENABLED_IRQS_READ
)
239 nr_irq_read_unsafe
++;
240 if (class->usage_mask
& LOCKF_USED_IN_SOFTIRQ_READ
)
241 nr_softirq_read_safe
++;
242 if (class->usage_mask
& LOCKF_ENABLED_SOFTIRQS_READ
)
243 nr_softirq_read_unsafe
++;
244 if (class->usage_mask
& LOCKF_USED_IN_HARDIRQ_READ
)
245 nr_hardirq_read_safe
++;
246 if (class->usage_mask
& LOCKF_ENABLED_HARDIRQS_READ
)
247 nr_hardirq_read_unsafe
++;
249 sum_forward_deps
+= count_forward_deps(class);
251 #ifdef CONFIG_DEBUG_LOCKDEP
252 DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks
) != nr_unused
);
254 seq_printf(m
, " lock-classes: %11lu [max: %lu]\n",
255 nr_lock_classes
, MAX_LOCKDEP_KEYS
);
256 seq_printf(m
, " direct dependencies: %11lu [max: %lu]\n",
257 nr_list_entries
, MAX_LOCKDEP_ENTRIES
);
258 seq_printf(m
, " indirect dependencies: %11lu\n",
262 * Total number of dependencies:
264 * All irq-safe locks may nest inside irq-unsafe locks,
265 * plus all the other known dependencies:
267 seq_printf(m
, " all direct dependencies: %11lu\n",
268 nr_irq_unsafe
* nr_irq_safe
+
269 nr_hardirq_unsafe
* nr_hardirq_safe
+
273 * Estimated factor between direct and indirect
277 factor
= sum_forward_deps
/ nr_list_entries
;
279 #ifdef CONFIG_PROVE_LOCKING
280 seq_printf(m
, " dependency chains: %11lu [max: %lu]\n",
281 nr_lock_chains
, MAX_LOCKDEP_CHAINS
);
284 #ifdef CONFIG_TRACE_IRQFLAGS
285 seq_printf(m
, " in-hardirq chains: %11u\n",
287 seq_printf(m
, " in-softirq chains: %11u\n",
290 seq_printf(m
, " in-process chains: %11u\n",
292 seq_printf(m
, " stack-trace entries: %11lu [max: %lu]\n",
293 nr_stack_trace_entries
, MAX_STACK_TRACE_ENTRIES
);
294 seq_printf(m
, " combined max dependencies: %11u\n",
295 (nr_hardirq_chains
+ 1) *
296 (nr_softirq_chains
+ 1) *
297 (nr_process_chains
+ 1)
299 seq_printf(m
, " hardirq-safe locks: %11lu\n",
301 seq_printf(m
, " hardirq-unsafe locks: %11lu\n",
303 seq_printf(m
, " softirq-safe locks: %11lu\n",
305 seq_printf(m
, " softirq-unsafe locks: %11lu\n",
307 seq_printf(m
, " irq-safe locks: %11lu\n",
309 seq_printf(m
, " irq-unsafe locks: %11lu\n",
312 seq_printf(m
, " hardirq-read-safe locks: %11lu\n",
313 nr_hardirq_read_safe
);
314 seq_printf(m
, " hardirq-read-unsafe locks: %11lu\n",
315 nr_hardirq_read_unsafe
);
316 seq_printf(m
, " softirq-read-safe locks: %11lu\n",
317 nr_softirq_read_safe
);
318 seq_printf(m
, " softirq-read-unsafe locks: %11lu\n",
319 nr_softirq_read_unsafe
);
320 seq_printf(m
, " irq-read-safe locks: %11lu\n",
322 seq_printf(m
, " irq-read-unsafe locks: %11lu\n",
325 seq_printf(m
, " uncategorized locks: %11lu\n",
327 seq_printf(m
, " unused locks: %11lu\n",
329 seq_printf(m
, " max locking depth: %11u\n",
331 seq_printf(m
, " max recursion depth: %11u\n",
332 max_recursion_depth
);
333 lockdep_stats_debug_show(m
);
334 seq_printf(m
, " debug_locks: %11u\n",
340 static int lockdep_stats_open(struct inode
*inode
, struct file
*file
)
342 return single_open(file
, lockdep_stats_show
, NULL
);
345 static const struct file_operations proc_lockdep_stats_operations
= {
346 .open
= lockdep_stats_open
,
349 .release
= seq_release
,
352 #ifdef CONFIG_LOCK_STAT
354 struct lock_stat_data
{
355 struct lock_class
*class;
356 struct lock_class_stats stats
;
359 struct lock_stat_seq
{
360 struct lock_stat_data
*iter
;
361 struct lock_stat_data
*iter_end
;
362 struct lock_stat_data stats
[MAX_LOCKDEP_KEYS
];
366 * sort on absolute number of contentions
368 static int lock_stat_cmp(const void *l
, const void *r
)
370 const struct lock_stat_data
*dl
= l
, *dr
= r
;
371 unsigned long nl
, nr
;
373 nl
= dl
->stats
.read_waittime
.nr
+ dl
->stats
.write_waittime
.nr
;
374 nr
= dr
->stats
.read_waittime
.nr
+ dr
->stats
.write_waittime
.nr
;
379 static void seq_line(struct seq_file
*m
, char c
, int offset
, int length
)
383 for (i
= 0; i
< offset
; i
++)
385 for (i
= 0; i
< length
; i
++)
386 seq_printf(m
, "%c", c
);
390 static void snprint_time(char *buf
, size_t bufsiz
, s64 nr
)
394 rem
= do_div(nr
, 1000); /* XXX: do_div_signed */
395 snprintf(buf
, bufsiz
, "%lld.%02d", (long long)nr
, ((int)rem
+5)/10);
398 static void seq_time(struct seq_file
*m
, s64 time
)
402 snprint_time(num
, sizeof(num
), time
);
403 seq_printf(m
, " %14s", num
);
406 static void seq_lock_time(struct seq_file
*m
, struct lock_time
*lt
)
408 seq_printf(m
, "%14lu", lt
->nr
);
409 seq_time(m
, lt
->min
);
410 seq_time(m
, lt
->max
);
411 seq_time(m
, lt
->total
);
414 static void seq_stats(struct seq_file
*m
, struct lock_stat_data
*data
)
417 struct lock_class
*class;
418 struct lock_class_stats
*stats
;
422 stats
= &data
->stats
;
425 if (class->name_version
> 1)
426 namelen
-= 2; /* XXX truncates versions > 9 */
431 char str
[KSYM_NAME_LEN
];
432 const char *key_name
;
434 key_name
= __get_key_name(class->key
, str
);
435 snprintf(name
, namelen
, "%s", key_name
);
437 snprintf(name
, namelen
, "%s", class->name
);
439 namelen
= strlen(name
);
440 if (class->name_version
> 1) {
441 snprintf(name
+namelen
, 3, "#%d", class->name_version
);
444 if (class->subclass
) {
445 snprintf(name
+namelen
, 3, "/%d", class->subclass
);
449 if (stats
->write_holdtime
.nr
) {
450 if (stats
->read_holdtime
.nr
)
451 seq_printf(m
, "%38s-W:", name
);
453 seq_printf(m
, "%40s:", name
);
455 seq_printf(m
, "%14lu ", stats
->bounces
[bounce_contended_write
]);
456 seq_lock_time(m
, &stats
->write_waittime
);
457 seq_printf(m
, " %14lu ", stats
->bounces
[bounce_acquired_write
]);
458 seq_lock_time(m
, &stats
->write_holdtime
);
462 if (stats
->read_holdtime
.nr
) {
463 seq_printf(m
, "%38s-R:", name
);
464 seq_printf(m
, "%14lu ", stats
->bounces
[bounce_contended_read
]);
465 seq_lock_time(m
, &stats
->read_waittime
);
466 seq_printf(m
, " %14lu ", stats
->bounces
[bounce_acquired_read
]);
467 seq_lock_time(m
, &stats
->read_holdtime
);
471 if (stats
->read_waittime
.nr
+ stats
->write_waittime
.nr
== 0)
474 if (stats
->read_holdtime
.nr
)
477 for (i
= 0; i
< ARRAY_SIZE(class->contention_point
); i
++) {
478 char sym
[KSYM_SYMBOL_LEN
];
481 if (class->contention_point
[i
] == 0)
485 seq_line(m
, '-', 40-namelen
, namelen
);
487 sprint_symbol(sym
, class->contention_point
[i
]);
488 snprintf(ip
, sizeof(ip
), "[<%p>]",
489 (void *)class->contention_point
[i
]);
490 seq_printf(m
, "%40s %14lu %29s %s\n", name
,
491 stats
->contention_point
[i
],
496 seq_line(m
, '.', 0, 40 + 1 + 10 * (14 + 1));
501 static void seq_header(struct seq_file
*m
)
503 seq_printf(m
, "lock_stat version 0.2\n");
504 seq_line(m
, '-', 0, 40 + 1 + 10 * (14 + 1));
505 seq_printf(m
, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
518 seq_line(m
, '-', 0, 40 + 1 + 10 * (14 + 1));
522 static void *ls_start(struct seq_file
*m
, loff_t
*pos
)
524 struct lock_stat_seq
*data
= m
->private;
526 if (data
->iter
== data
->stats
)
529 if (data
->iter
== data
->iter_end
)
535 static void *ls_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
537 struct lock_stat_seq
*data
= m
->private;
543 if (data
->iter
== data
->iter_end
)
549 static void ls_stop(struct seq_file
*m
, void *v
)
553 static int ls_show(struct seq_file
*m
, void *v
)
555 struct lock_stat_seq
*data
= m
->private;
557 seq_stats(m
, data
->iter
);
561 static struct seq_operations lockstat_ops
= {
568 static int lock_stat_open(struct inode
*inode
, struct file
*file
)
571 struct lock_class
*class;
572 struct lock_stat_seq
*data
= vmalloc(sizeof(struct lock_stat_seq
));
577 res
= seq_open(file
, &lockstat_ops
);
579 struct lock_stat_data
*iter
= data
->stats
;
580 struct seq_file
*m
= file
->private_data
;
583 list_for_each_entry(class, &all_lock_classes
, lock_entry
) {
585 iter
->stats
= lock_stats(class);
588 data
->iter_end
= iter
;
590 sort(data
->stats
, data
->iter_end
- data
->iter
,
591 sizeof(struct lock_stat_data
),
592 lock_stat_cmp
, NULL
);
601 static ssize_t
lock_stat_write(struct file
*file
, const char __user
*buf
,
602 size_t count
, loff_t
*ppos
)
604 struct lock_class
*class;
608 if (get_user(c
, buf
))
614 list_for_each_entry(class, &all_lock_classes
, lock_entry
)
615 clear_lock_stats(class);
620 static int lock_stat_release(struct inode
*inode
, struct file
*file
)
622 struct seq_file
*seq
= file
->private_data
;
626 return seq_release(inode
, file
);
629 static const struct file_operations proc_lock_stat_operations
= {
630 .open
= lock_stat_open
,
631 .write
= lock_stat_write
,
634 .release
= lock_stat_release
,
636 #endif /* CONFIG_LOCK_STAT */
638 static int __init
lockdep_proc_init(void)
640 struct proc_dir_entry
*entry
;
642 entry
= create_proc_entry("lockdep", S_IRUSR
, NULL
);
644 entry
->proc_fops
= &proc_lockdep_operations
;
646 entry
= create_proc_entry("lockdep_stats", S_IRUSR
, NULL
);
648 entry
->proc_fops
= &proc_lockdep_stats_operations
;
650 #ifdef CONFIG_LOCK_STAT
651 entry
= create_proc_entry("lock_stat", S_IRUSR
, NULL
);
653 entry
->proc_fops
= &proc_lock_stat_operations
;
659 __initcall(lockdep_proc_init
);