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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * kernel/lockdep_proc.c
4  *
5  * Runtime locking correctness validator
6  *
7  * Started by Ingo Molnar:
8  *
9  *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
10  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
11  *
12  * Code for /proc/lockdep and /proc/lockdep_stats:
13  *
14  */
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>
24 
25 #include "lockdep_internals.h"
26 
l_next(struct seq_file * m,void * v,loff_t * pos)27 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
28 {
29 	return seq_list_next(v, &all_lock_classes, pos);
30 }
31 
l_start(struct seq_file * m,loff_t * pos)32 static void *l_start(struct seq_file *m, loff_t *pos)
33 {
34 	return seq_list_start_head(&all_lock_classes, *pos);
35 }
36 
l_stop(struct seq_file * m,void * v)37 static void l_stop(struct seq_file *m, void *v)
38 {
39 }
40 
print_name(struct seq_file * m,struct lock_class * class)41 static void print_name(struct seq_file *m, struct lock_class *class)
42 {
43 	char str[KSYM_NAME_LEN];
44 	const char *name = class->name;
45 
46 	if (!name) {
47 		name = __get_key_name(class->key, str);
48 		seq_printf(m, "%s", name);
49 	} else{
50 		seq_printf(m, "%s", name);
51 		if (class->name_version > 1)
52 			seq_printf(m, "#%d", class->name_version);
53 		if (class->subclass)
54 			seq_printf(m, "/%d", class->subclass);
55 	}
56 }
57 
l_show(struct seq_file * m,void * v)58 static int l_show(struct seq_file *m, void *v)
59 {
60 	struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
61 	struct lock_list *entry;
62 	char usage[LOCK_USAGE_CHARS];
63 
64 	if (v == &all_lock_classes) {
65 		seq_printf(m, "all lock classes:\n");
66 		return 0;
67 	}
68 
69 	seq_printf(m, "%p", class->key);
70 #ifdef CONFIG_DEBUG_LOCKDEP
71 	seq_printf(m, " OPS:%8ld", debug_class_ops_read(class));
72 #endif
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));
76 #endif
77 
78 	get_usage_chars(class, usage);
79 	seq_printf(m, " %s", usage);
80 
81 	seq_printf(m, ": ");
82 	print_name(m, class);
83 	seq_puts(m, "\n");
84 
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);
89 			seq_puts(m, "\n");
90 		}
91 	}
92 	seq_puts(m, "\n");
93 
94 	return 0;
95 }
96 
97 static const struct seq_operations lockdep_ops = {
98 	.start	= l_start,
99 	.next	= l_next,
100 	.stop	= l_stop,
101 	.show	= l_show,
102 };
103 
104 #ifdef CONFIG_PROVE_LOCKING
lc_start(struct seq_file * m,loff_t * pos)105 static void *lc_start(struct seq_file *m, loff_t *pos)
106 {
107 	if (*pos < 0)
108 		return NULL;
109 
110 	if (*pos == 0)
111 		return SEQ_START_TOKEN;
112 
113 	return lock_chains + (*pos - 1);
114 }
115 
lc_next(struct seq_file * m,void * v,loff_t * pos)116 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
117 {
118 	*pos = lockdep_next_lockchain(*pos - 1) + 1;
119 	return lc_start(m, pos);
120 }
121 
lc_stop(struct seq_file * m,void * v)122 static void lc_stop(struct seq_file *m, void *v)
123 {
124 }
125 
lc_show(struct seq_file * m,void * v)126 static int lc_show(struct seq_file *m, void *v)
127 {
128 	struct lock_chain *chain = v;
129 	struct lock_class *class;
130 	int i;
131 
132 	if (v == SEQ_START_TOKEN) {
133 		if (nr_chain_hlocks > MAX_LOCKDEP_CHAIN_HLOCKS)
134 			seq_printf(m, "(buggered) ");
135 		seq_printf(m, "all lock chains:\n");
136 		return 0;
137 	}
138 
139 	seq_printf(m, "irq_context: %d\n", chain->irq_context);
140 
141 	for (i = 0; i < chain->depth; i++) {
142 		class = lock_chain_get_class(chain, i);
143 		if (!class->key)
144 			continue;
145 
146 		seq_printf(m, "[%p] ", class->key);
147 		print_name(m, class);
148 		seq_puts(m, "\n");
149 	}
150 	seq_puts(m, "\n");
151 
152 	return 0;
153 }
154 
155 static const struct seq_operations lockdep_chains_ops = {
156 	.start	= lc_start,
157 	.next	= lc_next,
158 	.stop	= lc_stop,
159 	.show	= lc_show,
160 };
161 #endif /* CONFIG_PROVE_LOCKING */
162 
lockdep_stats_debug_show(struct seq_file * m)163 static void lockdep_stats_debug_show(struct seq_file *m)
164 {
165 #ifdef CONFIG_DEBUG_LOCKDEP
166 	unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
167 			   hi2 = debug_atomic_read(hardirqs_off_events),
168 			   hr1 = debug_atomic_read(redundant_hardirqs_on),
169 			   hr2 = debug_atomic_read(redundant_hardirqs_off),
170 			   si1 = debug_atomic_read(softirqs_on_events),
171 			   si2 = debug_atomic_read(softirqs_off_events),
172 			   sr1 = debug_atomic_read(redundant_softirqs_on),
173 			   sr2 = debug_atomic_read(redundant_softirqs_off);
174 
175 	seq_printf(m, " chain lookup misses:           %11llu\n",
176 		debug_atomic_read(chain_lookup_misses));
177 	seq_printf(m, " chain lookup hits:             %11llu\n",
178 		debug_atomic_read(chain_lookup_hits));
179 	seq_printf(m, " cyclic checks:                 %11llu\n",
180 		debug_atomic_read(nr_cyclic_checks));
181 	seq_printf(m, " redundant checks:              %11llu\n",
182 		debug_atomic_read(nr_redundant_checks));
183 	seq_printf(m, " redundant links:               %11llu\n",
184 		debug_atomic_read(nr_redundant));
185 	seq_printf(m, " find-mask forwards checks:     %11llu\n",
186 		debug_atomic_read(nr_find_usage_forwards_checks));
187 	seq_printf(m, " find-mask backwards checks:    %11llu\n",
188 		debug_atomic_read(nr_find_usage_backwards_checks));
189 
190 	seq_printf(m, " hardirq on events:             %11llu\n", hi1);
191 	seq_printf(m, " hardirq off events:            %11llu\n", hi2);
192 	seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
193 	seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
194 	seq_printf(m, " softirq on events:             %11llu\n", si1);
195 	seq_printf(m, " softirq off events:            %11llu\n", si2);
196 	seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
197 	seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
198 #endif
199 }
200 
lockdep_stats_show(struct seq_file * m,void * v)201 static int lockdep_stats_show(struct seq_file *m, void *v)
202 {
203 	unsigned long nr_unused = 0, nr_uncategorized = 0,
204 		      nr_irq_safe = 0, nr_irq_unsafe = 0,
205 		      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
206 		      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
207 		      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
208 		      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
209 		      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
210 		      sum_forward_deps = 0;
211 
212 #ifdef CONFIG_PROVE_LOCKING
213 	struct lock_class *class;
214 
215 	list_for_each_entry(class, &all_lock_classes, lock_entry) {
216 
217 		if (class->usage_mask == 0)
218 			nr_unused++;
219 		if (class->usage_mask == LOCKF_USED)
220 			nr_uncategorized++;
221 		if (class->usage_mask & LOCKF_USED_IN_IRQ)
222 			nr_irq_safe++;
223 		if (class->usage_mask & LOCKF_ENABLED_IRQ)
224 			nr_irq_unsafe++;
225 		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
226 			nr_softirq_safe++;
227 		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
228 			nr_softirq_unsafe++;
229 		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
230 			nr_hardirq_safe++;
231 		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
232 			nr_hardirq_unsafe++;
233 		if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
234 			nr_irq_read_safe++;
235 		if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
236 			nr_irq_read_unsafe++;
237 		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
238 			nr_softirq_read_safe++;
239 		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
240 			nr_softirq_read_unsafe++;
241 		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
242 			nr_hardirq_read_safe++;
243 		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
244 			nr_hardirq_read_unsafe++;
245 
246 		sum_forward_deps += lockdep_count_forward_deps(class);
247 	}
248 #ifdef CONFIG_DEBUG_LOCKDEP
249 	DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
250 #endif
251 
252 #endif
253 	seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
254 			nr_lock_classes, MAX_LOCKDEP_KEYS);
255 	seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
256 			nr_list_entries, MAX_LOCKDEP_ENTRIES);
257 	seq_printf(m, " indirect dependencies:         %11lu\n",
258 			sum_forward_deps);
259 
260 	/*
261 	 * Total number of dependencies:
262 	 *
263 	 * All irq-safe locks may nest inside irq-unsafe locks,
264 	 * plus all the other known dependencies:
265 	 */
266 	seq_printf(m, " all direct dependencies:       %11lu\n",
267 			nr_irq_unsafe * nr_irq_safe +
268 			nr_hardirq_unsafe * nr_hardirq_safe +
269 			nr_list_entries);
270 
271 #ifdef CONFIG_PROVE_LOCKING
272 	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
273 			lock_chain_count(), MAX_LOCKDEP_CHAINS);
274 	seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
275 			nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
276 #endif
277 
278 #ifdef CONFIG_TRACE_IRQFLAGS
279 	seq_printf(m, " in-hardirq chains:             %11u\n",
280 			nr_hardirq_chains);
281 	seq_printf(m, " in-softirq chains:             %11u\n",
282 			nr_softirq_chains);
283 #endif
284 	seq_printf(m, " in-process chains:             %11u\n",
285 			nr_process_chains);
286 	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
287 			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
288 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
289 	seq_printf(m, " number of stack traces:        %llu\n",
290 		   lockdep_stack_trace_count());
291 	seq_printf(m, " number of stack hash chains:   %llu\n",
292 		   lockdep_stack_hash_count());
293 #endif
294 	seq_printf(m, " combined max dependencies:     %11u\n",
295 			(nr_hardirq_chains + 1) *
296 			(nr_softirq_chains + 1) *
297 			(nr_process_chains + 1)
298 	);
299 	seq_printf(m, " hardirq-safe locks:            %11lu\n",
300 			nr_hardirq_safe);
301 	seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
302 			nr_hardirq_unsafe);
303 	seq_printf(m, " softirq-safe locks:            %11lu\n",
304 			nr_softirq_safe);
305 	seq_printf(m, " softirq-unsafe locks:          %11lu\n",
306 			nr_softirq_unsafe);
307 	seq_printf(m, " irq-safe locks:                %11lu\n",
308 			nr_irq_safe);
309 	seq_printf(m, " irq-unsafe locks:              %11lu\n",
310 			nr_irq_unsafe);
311 
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",
321 			nr_irq_read_safe);
322 	seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
323 			nr_irq_read_unsafe);
324 
325 	seq_printf(m, " uncategorized locks:           %11lu\n",
326 			nr_uncategorized);
327 	seq_printf(m, " unused locks:                  %11lu\n",
328 			nr_unused);
329 	seq_printf(m, " max locking depth:             %11u\n",
330 			max_lockdep_depth);
331 #ifdef CONFIG_PROVE_LOCKING
332 	seq_printf(m, " max bfs queue depth:           %11u\n",
333 			max_bfs_queue_depth);
334 #endif
335 	lockdep_stats_debug_show(m);
336 	seq_printf(m, " debug_locks:                   %11u\n",
337 			debug_locks);
338 
339 	return 0;
340 }
341 
342 #ifdef CONFIG_LOCK_STAT
343 
344 struct lock_stat_data {
345 	struct lock_class *class;
346 	struct lock_class_stats stats;
347 };
348 
349 struct lock_stat_seq {
350 	struct lock_stat_data *iter_end;
351 	struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
352 };
353 
354 /*
355  * sort on absolute number of contentions
356  */
lock_stat_cmp(const void * l,const void * r)357 static int lock_stat_cmp(const void *l, const void *r)
358 {
359 	const struct lock_stat_data *dl = l, *dr = r;
360 	unsigned long nl, nr;
361 
362 	nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
363 	nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
364 
365 	return nr - nl;
366 }
367 
seq_line(struct seq_file * m,char c,int offset,int length)368 static void seq_line(struct seq_file *m, char c, int offset, int length)
369 {
370 	int i;
371 
372 	for (i = 0; i < offset; i++)
373 		seq_puts(m, " ");
374 	for (i = 0; i < length; i++)
375 		seq_printf(m, "%c", c);
376 	seq_puts(m, "\n");
377 }
378 
snprint_time(char * buf,size_t bufsiz,s64 nr)379 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
380 {
381 	s64 div;
382 	s32 rem;
383 
384 	nr += 5; /* for display rounding */
385 	div = div_s64_rem(nr, 1000, &rem);
386 	snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
387 }
388 
seq_time(struct seq_file * m,s64 time)389 static void seq_time(struct seq_file *m, s64 time)
390 {
391 	char num[15];
392 
393 	snprint_time(num, sizeof(num), time);
394 	seq_printf(m, " %14s", num);
395 }
396 
seq_lock_time(struct seq_file * m,struct lock_time * lt)397 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
398 {
399 	seq_printf(m, "%14lu", lt->nr);
400 	seq_time(m, lt->min);
401 	seq_time(m, lt->max);
402 	seq_time(m, lt->total);
403 	seq_time(m, lt->nr ? div_s64(lt->total, lt->nr) : 0);
404 }
405 
seq_stats(struct seq_file * m,struct lock_stat_data * data)406 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
407 {
408 	const struct lockdep_subclass_key *ckey;
409 	struct lock_class_stats *stats;
410 	struct lock_class *class;
411 	const char *cname;
412 	int i, namelen;
413 	char name[39];
414 
415 	class = data->class;
416 	stats = &data->stats;
417 
418 	namelen = 38;
419 	if (class->name_version > 1)
420 		namelen -= 2; /* XXX truncates versions > 9 */
421 	if (class->subclass)
422 		namelen -= 2;
423 
424 	rcu_read_lock_sched();
425 	cname = rcu_dereference_sched(class->name);
426 	ckey  = rcu_dereference_sched(class->key);
427 
428 	if (!cname && !ckey) {
429 		rcu_read_unlock_sched();
430 		return;
431 
432 	} else if (!cname) {
433 		char str[KSYM_NAME_LEN];
434 		const char *key_name;
435 
436 		key_name = __get_key_name(ckey, str);
437 		snprintf(name, namelen, "%s", key_name);
438 	} else {
439 		snprintf(name, namelen, "%s", cname);
440 	}
441 	rcu_read_unlock_sched();
442 
443 	namelen = strlen(name);
444 	if (class->name_version > 1) {
445 		snprintf(name+namelen, 3, "#%d", class->name_version);
446 		namelen += 2;
447 	}
448 	if (class->subclass) {
449 		snprintf(name+namelen, 3, "/%d", class->subclass);
450 		namelen += 2;
451 	}
452 
453 	if (stats->write_holdtime.nr) {
454 		if (stats->read_holdtime.nr)
455 			seq_printf(m, "%38s-W:", name);
456 		else
457 			seq_printf(m, "%40s:", name);
458 
459 		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
460 		seq_lock_time(m, &stats->write_waittime);
461 		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
462 		seq_lock_time(m, &stats->write_holdtime);
463 		seq_puts(m, "\n");
464 	}
465 
466 	if (stats->read_holdtime.nr) {
467 		seq_printf(m, "%38s-R:", name);
468 		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
469 		seq_lock_time(m, &stats->read_waittime);
470 		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
471 		seq_lock_time(m, &stats->read_holdtime);
472 		seq_puts(m, "\n");
473 	}
474 
475 	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
476 		return;
477 
478 	if (stats->read_holdtime.nr)
479 		namelen += 2;
480 
481 	for (i = 0; i < LOCKSTAT_POINTS; i++) {
482 		char ip[32];
483 
484 		if (class->contention_point[i] == 0)
485 			break;
486 
487 		if (!i)
488 			seq_line(m, '-', 40-namelen, namelen);
489 
490 		snprintf(ip, sizeof(ip), "[<%p>]",
491 				(void *)class->contention_point[i]);
492 		seq_printf(m, "%40s %14lu %29s %pS\n",
493 			   name, stats->contention_point[i],
494 			   ip, (void *)class->contention_point[i]);
495 	}
496 	for (i = 0; i < LOCKSTAT_POINTS; i++) {
497 		char ip[32];
498 
499 		if (class->contending_point[i] == 0)
500 			break;
501 
502 		if (!i)
503 			seq_line(m, '-', 40-namelen, namelen);
504 
505 		snprintf(ip, sizeof(ip), "[<%p>]",
506 				(void *)class->contending_point[i]);
507 		seq_printf(m, "%40s %14lu %29s %pS\n",
508 			   name, stats->contending_point[i],
509 			   ip, (void *)class->contending_point[i]);
510 	}
511 	if (i) {
512 		seq_puts(m, "\n");
513 		seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
514 		seq_puts(m, "\n");
515 	}
516 }
517 
seq_header(struct seq_file * m)518 static void seq_header(struct seq_file *m)
519 {
520 	seq_puts(m, "lock_stat version 0.4\n");
521 
522 	if (unlikely(!debug_locks))
523 		seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
524 
525 	seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
526 	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
527 			"%14s %14s\n",
528 			"class name",
529 			"con-bounces",
530 			"contentions",
531 			"waittime-min",
532 			"waittime-max",
533 			"waittime-total",
534 			"waittime-avg",
535 			"acq-bounces",
536 			"acquisitions",
537 			"holdtime-min",
538 			"holdtime-max",
539 			"holdtime-total",
540 			"holdtime-avg");
541 	seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
542 	seq_printf(m, "\n");
543 }
544 
ls_start(struct seq_file * m,loff_t * pos)545 static void *ls_start(struct seq_file *m, loff_t *pos)
546 {
547 	struct lock_stat_seq *data = m->private;
548 	struct lock_stat_data *iter;
549 
550 	if (*pos == 0)
551 		return SEQ_START_TOKEN;
552 
553 	iter = data->stats + (*pos - 1);
554 	if (iter >= data->iter_end)
555 		iter = NULL;
556 
557 	return iter;
558 }
559 
ls_next(struct seq_file * m,void * v,loff_t * pos)560 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
561 {
562 	(*pos)++;
563 	return ls_start(m, pos);
564 }
565 
ls_stop(struct seq_file * m,void * v)566 static void ls_stop(struct seq_file *m, void *v)
567 {
568 }
569 
ls_show(struct seq_file * m,void * v)570 static int ls_show(struct seq_file *m, void *v)
571 {
572 	if (v == SEQ_START_TOKEN)
573 		seq_header(m);
574 	else
575 		seq_stats(m, v);
576 
577 	return 0;
578 }
579 
580 static const struct seq_operations lockstat_ops = {
581 	.start	= ls_start,
582 	.next	= ls_next,
583 	.stop	= ls_stop,
584 	.show	= ls_show,
585 };
586 
lock_stat_open(struct inode * inode,struct file * file)587 static int lock_stat_open(struct inode *inode, struct file *file)
588 {
589 	int res;
590 	struct lock_class *class;
591 	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
592 
593 	if (!data)
594 		return -ENOMEM;
595 
596 	res = seq_open(file, &lockstat_ops);
597 	if (!res) {
598 		struct lock_stat_data *iter = data->stats;
599 		struct seq_file *m = file->private_data;
600 
601 		list_for_each_entry(class, &all_lock_classes, lock_entry) {
602 			iter->class = class;
603 			iter->stats = lock_stats(class);
604 			iter++;
605 		}
606 		data->iter_end = iter;
607 
608 		sort(data->stats, data->iter_end - data->stats,
609 				sizeof(struct lock_stat_data),
610 				lock_stat_cmp, NULL);
611 
612 		m->private = data;
613 	} else
614 		vfree(data);
615 
616 	return res;
617 }
618 
lock_stat_write(struct file * file,const char __user * buf,size_t count,loff_t * ppos)619 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
620 			       size_t count, loff_t *ppos)
621 {
622 	struct lock_class *class;
623 	char c;
624 
625 	if (count) {
626 		if (get_user(c, buf))
627 			return -EFAULT;
628 
629 		if (c != '0')
630 			return count;
631 
632 		list_for_each_entry(class, &all_lock_classes, lock_entry)
633 			clear_lock_stats(class);
634 	}
635 	return count;
636 }
637 
lock_stat_release(struct inode * inode,struct file * file)638 static int lock_stat_release(struct inode *inode, struct file *file)
639 {
640 	struct seq_file *seq = file->private_data;
641 
642 	vfree(seq->private);
643 	return seq_release(inode, file);
644 }
645 
646 static const struct file_operations proc_lock_stat_operations = {
647 	.open		= lock_stat_open,
648 	.write		= lock_stat_write,
649 	.read		= seq_read,
650 	.llseek		= seq_lseek,
651 	.release	= lock_stat_release,
652 };
653 #endif /* CONFIG_LOCK_STAT */
654 
lockdep_proc_init(void)655 static int __init lockdep_proc_init(void)
656 {
657 	proc_create_seq("lockdep", S_IRUSR, NULL, &lockdep_ops);
658 #ifdef CONFIG_PROVE_LOCKING
659 	proc_create_seq("lockdep_chains", S_IRUSR, NULL, &lockdep_chains_ops);
660 #endif
661 	proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show);
662 #ifdef CONFIG_LOCK_STAT
663 	proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
664 		    &proc_lock_stat_operations);
665 #endif
666 
667 	return 0;
668 }
669 
670 __initcall(lockdep_proc_init);
671 
672