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Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Ingo Molnara8f24a32006-07-03 00:24:52 -07002/*
3 * kernel/lockdep_proc.c
4 *
5 * Runtime locking correctness validator
6 *
7 * Started by Ingo Molnar:
8 *
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -07009 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
Peter Zijlstra90eec102015-11-16 11:08:45 +010010 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
Ingo Molnara8f24a32006-07-03 00:24:52 -070011 *
12 * Code for /proc/lockdep and /proc/lockdep_stats:
13 *
14 */
Paul Gortmaker9984de12011-05-23 14:51:41 -040015#include <linux/export.h>
Ingo Molnara8f24a32006-07-03 00:24:52 -070016#include <linux/proc_fs.h>
17#include <linux/seq_file.h>
18#include <linux/kallsyms.h>
19#include <linux/debug_locks.h>
Peter Zijlstrac46261d2007-07-19 01:48:57 -070020#include <linux/vmalloc.h>
21#include <linux/sort.h>
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080022#include <linux/uaccess.h>
Peter Zijlstrac46261d2007-07-19 01:48:57 -070023#include <asm/div64.h>
Ingo Molnara8f24a32006-07-03 00:24:52 -070024
25#include "lockdep_internals.h"
26
Waiman Longfb7275a2022-02-10 22:55:26 -050027/*
28 * Since iteration of lock_classes is done without holding the lockdep lock,
29 * it is not safe to iterate all_lock_classes list directly as the iteration
30 * may branch off to free_lock_classes or the zapped list. Iteration is done
31 * directly on the lock_classes array by checking the lock_classes_in_use
32 * bitmap and max_lock_class_idx.
33 */
34#define iterate_lock_classes(idx, class) \
35 for (idx = 0, class = lock_classes; idx <= max_lock_class_idx; \
36 idx++, class++)
37
Ingo Molnara8f24a32006-07-03 00:24:52 -070038static void *l_next(struct seq_file *m, void *v, loff_t *pos)
39{
Waiman Longfb7275a2022-02-10 22:55:26 -050040 struct lock_class *class = v;
41
42 ++class;
43 *pos = class - lock_classes;
44 return (*pos > max_lock_class_idx) ? NULL : class;
Ingo Molnara8f24a32006-07-03 00:24:52 -070045}
46
47static void *l_start(struct seq_file *m, loff_t *pos)
48{
Waiman Longfb7275a2022-02-10 22:55:26 -050049 unsigned long idx = *pos;
50
51 if (idx > max_lock_class_idx)
52 return NULL;
53 return lock_classes + idx;
Ingo Molnara8f24a32006-07-03 00:24:52 -070054}
55
56static void l_stop(struct seq_file *m, void *v)
57{
58}
59
Jason Baron068135e2007-02-10 01:44:59 -080060static void print_name(struct seq_file *m, struct lock_class *class)
61{
Cyrill Gorcunov99fb4a12012-10-20 23:05:19 +040062 char str[KSYM_NAME_LEN];
Jason Baron068135e2007-02-10 01:44:59 -080063 const char *name = class->name;
64
65 if (!name) {
66 name = __get_key_name(class->key, str);
67 seq_printf(m, "%s", name);
68 } else{
69 seq_printf(m, "%s", name);
70 if (class->name_version > 1)
71 seq_printf(m, "#%d", class->name_version);
72 if (class->subclass)
73 seq_printf(m, "/%d", class->subclass);
74 }
75}
76
Ingo Molnara8f24a32006-07-03 00:24:52 -070077static int l_show(struct seq_file *m, void *v)
78{
Waiman Longfb7275a2022-02-10 22:55:26 -050079 struct lock_class *class = v;
Jason Baron068135e2007-02-10 01:44:59 -080080 struct lock_list *entry;
Peter Zijlstraf510b232009-01-22 17:53:47 +010081 char usage[LOCK_USAGE_CHARS];
Waiman Longfb7275a2022-02-10 22:55:26 -050082 int idx = class - lock_classes;
Ingo Molnara8f24a32006-07-03 00:24:52 -070083
Waiman Longfb7275a2022-02-10 22:55:26 -050084 if (v == lock_classes)
Tim Pepper94c61c02007-10-11 22:11:11 +020085 seq_printf(m, "all lock classes:\n");
Waiman Longfb7275a2022-02-10 22:55:26 -050086
87 if (!test_bit(idx, lock_classes_in_use))
Tim Pepper94c61c02007-10-11 22:11:11 +020088 return 0;
Tim Pepper94c61c02007-10-11 22:11:11 +020089
Ingo Molnara8f24a32006-07-03 00:24:52 -070090 seq_printf(m, "%p", class->key);
91#ifdef CONFIG_DEBUG_LOCKDEP
Waiman Long8ca2b56c2018-10-03 13:07:18 -040092 seq_printf(m, " OPS:%8ld", debug_class_ops_read(class));
Ingo Molnara8f24a32006-07-03 00:24:52 -070093#endif
Xiongwei Song4840ce22021-06-29 21:59:16 +080094 if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
95 seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
96 seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
Ingo Molnara8f24a32006-07-03 00:24:52 -070097
Xiongwei Song4840ce22021-06-29 21:59:16 +080098 get_usage_chars(class, usage);
99 seq_printf(m, " %s", usage);
100 }
Ingo Molnara8f24a32006-07-03 00:24:52 -0700101
Jason Baron068135e2007-02-10 01:44:59 -0800102 seq_printf(m, ": ");
103 print_name(m, class);
104 seq_puts(m, "\n");
105
Xiongwei Song4840ce22021-06-29 21:59:16 +0800106 if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
107 list_for_each_entry(entry, &class->locks_after, entry) {
108 if (entry->distance == 1) {
109 seq_printf(m, " -> [%p] ", entry->class->key);
110 print_name(m, entry->class);
111 seq_puts(m, "\n");
112 }
Jason Baron068135e2007-02-10 01:44:59 -0800113 }
Xiongwei Song4840ce22021-06-29 21:59:16 +0800114 seq_puts(m, "\n");
Ingo Molnara8f24a32006-07-03 00:24:52 -0700115 }
Ingo Molnara8f24a32006-07-03 00:24:52 -0700116
117 return 0;
118}
119
Helge Deller15ad7cd2006-12-06 20:40:36 -0800120static const struct seq_operations lockdep_ops = {
Ingo Molnara8f24a32006-07-03 00:24:52 -0700121 .start = l_start,
122 .next = l_next,
123 .stop = l_stop,
124 .show = l_show,
125};
126
Huang, Yingcd1a28e2008-06-23 11:20:54 +0800127#ifdef CONFIG_PROVE_LOCKING
Huang, Ying443cd502008-06-20 16:39:21 +0800128static void *lc_start(struct seq_file *m, loff_t *pos)
129{
Bart Van Assche22126842019-02-14 15:00:48 -0800130 if (*pos < 0)
131 return NULL;
132
Huang, Ying443cd502008-06-20 16:39:21 +0800133 if (*pos == 0)
134 return SEQ_START_TOKEN;
135
Bart Van Assche22126842019-02-14 15:00:48 -0800136 return lock_chains + (*pos - 1);
Huang, Ying443cd502008-06-20 16:39:21 +0800137}
138
Li Zefan12aac192009-08-17 13:40:39 +0800139static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
140{
Bart Van Assche22126842019-02-14 15:00:48 -0800141 *pos = lockdep_next_lockchain(*pos - 1) + 1;
Li Zefan12aac192009-08-17 13:40:39 +0800142 return lc_start(m, pos);
143}
144
Huang, Ying443cd502008-06-20 16:39:21 +0800145static void lc_stop(struct seq_file *m, void *v)
146{
147}
148
149static int lc_show(struct seq_file *m, void *v)
150{
151 struct lock_chain *chain = v;
152 struct lock_class *class;
153 int i;
Waiman Longb9875e92020-02-06 10:24:04 -0500154 static const char * const irq_strs[] = {
155 [0] = "0",
156 [LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq",
157 [LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq",
158 [LOCK_CHAIN_SOFTIRQ_CONTEXT|
159 LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq",
160 };
Huang, Ying443cd502008-06-20 16:39:21 +0800161
162 if (v == SEQ_START_TOKEN) {
Waiman Long810507f2020-02-06 10:24:08 -0500163 if (!nr_free_chain_hlocks)
Peter Zijlstra75dd6022016-03-30 11:36:59 +0200164 seq_printf(m, "(buggered) ");
Huang, Ying443cd502008-06-20 16:39:21 +0800165 seq_printf(m, "all lock chains:\n");
166 return 0;
167 }
168
Waiman Longb9875e92020-02-06 10:24:04 -0500169 seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]);
Huang, Ying443cd502008-06-20 16:39:21 +0800170
171 for (i = 0; i < chain->depth; i++) {
172 class = lock_chain_get_class(chain, i);
Rabin Vincent8bfe0292008-08-11 09:30:26 +0200173 if (!class->key)
174 continue;
175
Huang, Ying443cd502008-06-20 16:39:21 +0800176 seq_printf(m, "[%p] ", class->key);
177 print_name(m, class);
178 seq_puts(m, "\n");
179 }
180 seq_puts(m, "\n");
181
182 return 0;
183}
184
185static const struct seq_operations lockdep_chains_ops = {
186 .start = lc_start,
187 .next = lc_next,
188 .stop = lc_stop,
189 .show = lc_show,
190};
Huang, Yingcd1a28e2008-06-23 11:20:54 +0800191#endif /* CONFIG_PROVE_LOCKING */
Huang, Ying443cd502008-06-20 16:39:21 +0800192
Ingo Molnara8f24a32006-07-03 00:24:52 -0700193static void lockdep_stats_debug_show(struct seq_file *m)
194{
195#ifdef CONFIG_DEBUG_LOCKDEP
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200196 unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
197 hi2 = debug_atomic_read(hardirqs_off_events),
198 hr1 = debug_atomic_read(redundant_hardirqs_on),
199 hr2 = debug_atomic_read(redundant_hardirqs_off),
200 si1 = debug_atomic_read(softirqs_on_events),
201 si2 = debug_atomic_read(softirqs_off_events),
202 sr1 = debug_atomic_read(redundant_softirqs_on),
203 sr2 = debug_atomic_read(redundant_softirqs_off);
Ingo Molnara8f24a32006-07-03 00:24:52 -0700204
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200205 seq_printf(m, " chain lookup misses: %11llu\n",
206 debug_atomic_read(chain_lookup_misses));
207 seq_printf(m, " chain lookup hits: %11llu\n",
208 debug_atomic_read(chain_lookup_hits));
209 seq_printf(m, " cyclic checks: %11llu\n",
210 debug_atomic_read(nr_cyclic_checks));
Peter Zijlstraae813302017-03-03 10:13:38 +0100211 seq_printf(m, " redundant checks: %11llu\n",
212 debug_atomic_read(nr_redundant_checks));
213 seq_printf(m, " redundant links: %11llu\n",
214 debug_atomic_read(nr_redundant));
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200215 seq_printf(m, " find-mask forwards checks: %11llu\n",
216 debug_atomic_read(nr_find_usage_forwards_checks));
217 seq_printf(m, " find-mask backwards checks: %11llu\n",
218 debug_atomic_read(nr_find_usage_backwards_checks));
Ingo Molnara8f24a32006-07-03 00:24:52 -0700219
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200220 seq_printf(m, " hardirq on events: %11llu\n", hi1);
221 seq_printf(m, " hardirq off events: %11llu\n", hi2);
222 seq_printf(m, " redundant hardirq ons: %11llu\n", hr1);
223 seq_printf(m, " redundant hardirq offs: %11llu\n", hr2);
224 seq_printf(m, " softirq on events: %11llu\n", si1);
225 seq_printf(m, " softirq off events: %11llu\n", si2);
226 seq_printf(m, " redundant softirq ons: %11llu\n", sr1);
227 seq_printf(m, " redundant softirq offs: %11llu\n", sr2);
Ingo Molnara8f24a32006-07-03 00:24:52 -0700228#endif
229}
230
231static int lockdep_stats_show(struct seq_file *m, void *v)
232{
Ingo Molnara8f24a32006-07-03 00:24:52 -0700233 unsigned long nr_unused = 0, nr_uncategorized = 0,
234 nr_irq_safe = 0, nr_irq_unsafe = 0,
235 nr_softirq_safe = 0, nr_softirq_unsafe = 0,
236 nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
237 nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
238 nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
239 nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
Sergey Senozhatskydec29602011-03-23 14:38:28 +0200240 sum_forward_deps = 0;
Ingo Molnara8f24a32006-07-03 00:24:52 -0700241
Yuyang Du68d41d82019-07-09 18:15:22 +0800242#ifdef CONFIG_PROVE_LOCKING
Arnd Bergmann68037aa2019-07-15 11:27:49 +0200243 struct lock_class *class;
Waiman Longfb7275a2022-02-10 22:55:26 -0500244 unsigned long idx;
Arnd Bergmann68037aa2019-07-15 11:27:49 +0200245
Waiman Longfb7275a2022-02-10 22:55:26 -0500246 iterate_lock_classes(idx, class) {
247 if (!test_bit(idx, lock_classes_in_use))
248 continue;
Ingo Molnara8f24a32006-07-03 00:24:52 -0700249
250 if (class->usage_mask == 0)
251 nr_unused++;
252 if (class->usage_mask == LOCKF_USED)
253 nr_uncategorized++;
254 if (class->usage_mask & LOCKF_USED_IN_IRQ)
255 nr_irq_safe++;
Peter Zijlstra4fc95e82009-01-22 13:10:52 +0100256 if (class->usage_mask & LOCKF_ENABLED_IRQ)
Ingo Molnara8f24a32006-07-03 00:24:52 -0700257 nr_irq_unsafe++;
258 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
259 nr_softirq_safe++;
Peter Zijlstra4fc95e82009-01-22 13:10:52 +0100260 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
Ingo Molnara8f24a32006-07-03 00:24:52 -0700261 nr_softirq_unsafe++;
262 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
263 nr_hardirq_safe++;
Peter Zijlstra4fc95e82009-01-22 13:10:52 +0100264 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
Ingo Molnara8f24a32006-07-03 00:24:52 -0700265 nr_hardirq_unsafe++;
266 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
267 nr_irq_read_safe++;
Peter Zijlstra4fc95e82009-01-22 13:10:52 +0100268 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
Ingo Molnara8f24a32006-07-03 00:24:52 -0700269 nr_irq_read_unsafe++;
270 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
271 nr_softirq_read_safe++;
Peter Zijlstra4fc95e82009-01-22 13:10:52 +0100272 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
Ingo Molnara8f24a32006-07-03 00:24:52 -0700273 nr_softirq_read_unsafe++;
274 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
275 nr_hardirq_read_safe++;
Peter Zijlstra4fc95e82009-01-22 13:10:52 +0100276 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
Ingo Molnara8f24a32006-07-03 00:24:52 -0700277 nr_hardirq_read_unsafe++;
278
David Miller419ca3f2008-07-29 21:45:03 -0700279 sum_forward_deps += lockdep_count_forward_deps(class);
Ingo Molnara8f24a32006-07-03 00:24:52 -0700280 }
Waiman Longfb7275a2022-02-10 22:55:26 -0500281
Robert P. J. Day501b9eb2007-02-10 01:46:34 -0800282#ifdef CONFIG_DEBUG_LOCKDEP
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200283 DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
Ingo Molnara8f24a32006-07-03 00:24:52 -0700284#endif
Yuyang Du68d41d82019-07-09 18:15:22 +0800285
286#endif
Ingo Molnara8f24a32006-07-03 00:24:52 -0700287 seq_printf(m, " lock-classes: %11lu [max: %lu]\n",
288 nr_lock_classes, MAX_LOCKDEP_KEYS);
289 seq_printf(m, " direct dependencies: %11lu [max: %lu]\n",
290 nr_list_entries, MAX_LOCKDEP_ENTRIES);
291 seq_printf(m, " indirect dependencies: %11lu\n",
292 sum_forward_deps);
293
294 /*
295 * Total number of dependencies:
296 *
297 * All irq-safe locks may nest inside irq-unsafe locks,
298 * plus all the other known dependencies:
299 */
300 seq_printf(m, " all direct dependencies: %11lu\n",
301 nr_irq_unsafe * nr_irq_safe +
302 nr_hardirq_unsafe * nr_hardirq_safe +
303 nr_list_entries);
304
Peter Zijlstra8e182572007-07-19 01:48:54 -0700305#ifdef CONFIG_PROVE_LOCKING
Ingo Molnara8f24a32006-07-03 00:24:52 -0700306 seq_printf(m, " dependency chains: %11lu [max: %lu]\n",
Bart Van Assche22126842019-02-14 15:00:48 -0800307 lock_chain_count(), MAX_LOCKDEP_CHAINS);
Waiman Long810507f2020-02-06 10:24:08 -0500308 seq_printf(m, " dependency chain hlocks used: %11lu [max: %lu]\n",
309 MAX_LOCKDEP_CHAIN_HLOCKS -
310 (nr_free_chain_hlocks + nr_lost_chain_hlocks),
311 MAX_LOCKDEP_CHAIN_HLOCKS);
312 seq_printf(m, " dependency chain hlocks lost: %11u\n",
313 nr_lost_chain_hlocks);
Peter Zijlstra8e182572007-07-19 01:48:54 -0700314#endif
Ingo Molnara8f24a32006-07-03 00:24:52 -0700315
316#ifdef CONFIG_TRACE_IRQFLAGS
317 seq_printf(m, " in-hardirq chains: %11u\n",
318 nr_hardirq_chains);
319 seq_printf(m, " in-softirq chains: %11u\n",
320 nr_softirq_chains);
321#endif
322 seq_printf(m, " in-process chains: %11u\n",
323 nr_process_chains);
324 seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n",
325 nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
Bart Van Assche8c779222019-07-22 11:24:43 -0700326#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
Waiman Longa030f972019-12-11 16:31:39 -0500327 seq_printf(m, " number of stack traces: %11llu\n",
Bart Van Assche8c779222019-07-22 11:24:43 -0700328 lockdep_stack_trace_count());
Waiman Longa030f972019-12-11 16:31:39 -0500329 seq_printf(m, " number of stack hash chains: %11llu\n",
Bart Van Assche8c779222019-07-22 11:24:43 -0700330 lockdep_stack_hash_count());
331#endif
Ingo Molnara8f24a32006-07-03 00:24:52 -0700332 seq_printf(m, " combined max dependencies: %11u\n",
333 (nr_hardirq_chains + 1) *
334 (nr_softirq_chains + 1) *
335 (nr_process_chains + 1)
336 );
337 seq_printf(m, " hardirq-safe locks: %11lu\n",
338 nr_hardirq_safe);
339 seq_printf(m, " hardirq-unsafe locks: %11lu\n",
340 nr_hardirq_unsafe);
341 seq_printf(m, " softirq-safe locks: %11lu\n",
342 nr_softirq_safe);
343 seq_printf(m, " softirq-unsafe locks: %11lu\n",
344 nr_softirq_unsafe);
345 seq_printf(m, " irq-safe locks: %11lu\n",
346 nr_irq_safe);
347 seq_printf(m, " irq-unsafe locks: %11lu\n",
348 nr_irq_unsafe);
349
350 seq_printf(m, " hardirq-read-safe locks: %11lu\n",
351 nr_hardirq_read_safe);
352 seq_printf(m, " hardirq-read-unsafe locks: %11lu\n",
353 nr_hardirq_read_unsafe);
354 seq_printf(m, " softirq-read-safe locks: %11lu\n",
355 nr_softirq_read_safe);
356 seq_printf(m, " softirq-read-unsafe locks: %11lu\n",
357 nr_softirq_read_unsafe);
358 seq_printf(m, " irq-read-safe locks: %11lu\n",
359 nr_irq_read_safe);
360 seq_printf(m, " irq-read-unsafe locks: %11lu\n",
361 nr_irq_read_unsafe);
362
363 seq_printf(m, " uncategorized locks: %11lu\n",
364 nr_uncategorized);
365 seq_printf(m, " unused locks: %11lu\n",
366 nr_unused);
367 seq_printf(m, " max locking depth: %11u\n",
368 max_lockdep_depth);
Ingo Molnarbbfa2622009-08-02 14:44:24 +0200369#ifdef CONFIG_PROVE_LOCKING
Ming Lei12f3dfd2009-07-16 15:44:29 +0200370 seq_printf(m, " max bfs queue depth: %11u\n",
371 max_bfs_queue_depth);
Ingo Molnarbbfa2622009-08-02 14:44:24 +0200372#endif
Waiman Longfb7275a2022-02-10 22:55:26 -0500373 seq_printf(m, " max lock class index: %11lu\n",
374 max_lock_class_idx);
Ingo Molnara8f24a32006-07-03 00:24:52 -0700375 lockdep_stats_debug_show(m);
376 seq_printf(m, " debug_locks: %11u\n",
377 debug_locks);
378
Waiman Long1d44bcb2020-02-06 10:24:05 -0500379 /*
Ingo Molnare2db7592021-03-22 02:35:05 +0100380 * Zapped classes and lockdep data buffers reuse statistics.
Waiman Long1d44bcb2020-02-06 10:24:05 -0500381 */
382 seq_puts(m, "\n");
383 seq_printf(m, " zapped classes: %11lu\n",
384 nr_zapped_classes);
Waiman Long797b82eb2020-02-06 10:24:07 -0500385#ifdef CONFIG_PROVE_LOCKING
386 seq_printf(m, " zapped lock chains: %11lu\n",
387 nr_zapped_lock_chains);
Waiman Long810507f2020-02-06 10:24:08 -0500388 seq_printf(m, " large chain blocks: %11u\n",
389 nr_large_chain_blocks);
Waiman Long797b82eb2020-02-06 10:24:07 -0500390#endif
Ingo Molnara8f24a32006-07-03 00:24:52 -0700391 return 0;
392}
393
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700394#ifdef CONFIG_LOCK_STAT
395
396struct lock_stat_data {
397 struct lock_class *class;
398 struct lock_class_stats stats;
399};
400
401struct lock_stat_seq {
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700402 struct lock_stat_data *iter_end;
403 struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
404};
405
406/*
407 * sort on absolute number of contentions
408 */
409static int lock_stat_cmp(const void *l, const void *r)
410{
411 const struct lock_stat_data *dl = l, *dr = r;
412 unsigned long nl, nr;
413
414 nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
415 nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
416
417 return nr - nl;
418}
419
420static void seq_line(struct seq_file *m, char c, int offset, int length)
421{
422 int i;
423
424 for (i = 0; i < offset; i++)
425 seq_puts(m, " ");
426 for (i = 0; i < length; i++)
427 seq_printf(m, "%c", c);
428 seq_puts(m, "\n");
429}
430
431static void snprint_time(char *buf, size_t bufsiz, s64 nr)
432{
Peter Zijlstra6918bc52008-09-23 15:33:41 +0200433 s64 div;
434 s32 rem;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700435
Joe Korty2189459d2008-08-25 17:15:33 -0400436 nr += 5; /* for display rounding */
Peter Zijlstra6918bc52008-09-23 15:33:41 +0200437 div = div_s64_rem(nr, 1000, &rem);
438 snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700439}
440
441static void seq_time(struct seq_file *m, s64 time)
442{
443 char num[15];
444
445 snprint_time(num, sizeof(num), time);
446 seq_printf(m, " %14s", num);
447}
448
449static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
450{
451 seq_printf(m, "%14lu", lt->nr);
452 seq_time(m, lt->min);
453 seq_time(m, lt->max);
454 seq_time(m, lt->total);
Chris Wilsona7ef9b22020-07-25 19:51:10 +0100455 seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700456}
457
458static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
459{
Bart Van Assche364f6af2019-07-22 11:24:40 -0700460 const struct lockdep_subclass_key *ckey;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700461 struct lock_class_stats *stats;
Peter Zijlstracee34d82015-06-02 12:50:13 +0200462 struct lock_class *class;
463 const char *cname;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700464 int i, namelen;
Peter Zijlstracee34d82015-06-02 12:50:13 +0200465 char name[39];
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700466
467 class = data->class;
468 stats = &data->stats;
469
Peter Zijlstrad38e1d52007-07-19 01:49:01 -0700470 namelen = 38;
471 if (class->name_version > 1)
472 namelen -= 2; /* XXX truncates versions > 9 */
473 if (class->subclass)
474 namelen -= 2;
475
Peter Zijlstracee34d82015-06-02 12:50:13 +0200476 rcu_read_lock_sched();
477 cname = rcu_dereference_sched(class->name);
478 ckey = rcu_dereference_sched(class->key);
479
480 if (!cname && !ckey) {
481 rcu_read_unlock_sched();
482 return;
483
484 } else if (!cname) {
Peter Zijlstrad38e1d52007-07-19 01:49:01 -0700485 char str[KSYM_NAME_LEN];
486 const char *key_name;
487
Peter Zijlstracee34d82015-06-02 12:50:13 +0200488 key_name = __get_key_name(ckey, str);
Peter Zijlstrad38e1d52007-07-19 01:49:01 -0700489 snprintf(name, namelen, "%s", key_name);
490 } else {
Peter Zijlstracee34d82015-06-02 12:50:13 +0200491 snprintf(name, namelen, "%s", cname);
Peter Zijlstrad38e1d52007-07-19 01:49:01 -0700492 }
Peter Zijlstracee34d82015-06-02 12:50:13 +0200493 rcu_read_unlock_sched();
494
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700495 namelen = strlen(name);
Peter Zijlstrad38e1d52007-07-19 01:49:01 -0700496 if (class->name_version > 1) {
497 snprintf(name+namelen, 3, "#%d", class->name_version);
498 namelen += 2;
499 }
500 if (class->subclass) {
501 snprintf(name+namelen, 3, "/%d", class->subclass);
502 namelen += 2;
503 }
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700504
505 if (stats->write_holdtime.nr) {
506 if (stats->read_holdtime.nr)
507 seq_printf(m, "%38s-W:", name);
508 else
509 seq_printf(m, "%40s:", name);
510
Peter Zijlstra96645672007-07-19 01:49:00 -0700511 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700512 seq_lock_time(m, &stats->write_waittime);
Peter Zijlstra96645672007-07-19 01:49:00 -0700513 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700514 seq_lock_time(m, &stats->write_holdtime);
515 seq_puts(m, "\n");
516 }
517
518 if (stats->read_holdtime.nr) {
519 seq_printf(m, "%38s-R:", name);
Peter Zijlstra96645672007-07-19 01:49:00 -0700520 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700521 seq_lock_time(m, &stats->read_waittime);
Peter Zijlstra96645672007-07-19 01:49:00 -0700522 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700523 seq_lock_time(m, &stats->read_holdtime);
524 seq_puts(m, "\n");
525 }
526
527 if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
528 return;
529
530 if (stats->read_holdtime.nr)
531 namelen += 2;
532
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200533 for (i = 0; i < LOCKSTAT_POINTS; i++) {
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700534 char ip[32];
535
536 if (class->contention_point[i] == 0)
537 break;
538
539 if (!i)
540 seq_line(m, '-', 40-namelen, namelen);
541
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700542 snprintf(ip, sizeof(ip), "[<%p>]",
543 (void *)class->contention_point[i]);
Joe Perches3cf9b852010-11-05 16:12:38 -0700544 seq_printf(m, "%40s %14lu %29s %pS\n",
545 name, stats->contention_point[i],
546 ip, (void *)class->contention_point[i]);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700547 }
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200548 for (i = 0; i < LOCKSTAT_POINTS; i++) {
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200549 char ip[32];
550
551 if (class->contending_point[i] == 0)
552 break;
553
554 if (!i)
555 seq_line(m, '-', 40-namelen, namelen);
556
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200557 snprintf(ip, sizeof(ip), "[<%p>]",
558 (void *)class->contending_point[i]);
Joe Perches3cf9b852010-11-05 16:12:38 -0700559 seq_printf(m, "%40s %14lu %29s %pS\n",
560 name, stats->contending_point[i],
561 ip, (void *)class->contending_point[i]);
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200562 }
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700563 if (i) {
564 seq_puts(m, "\n");
Davidlohr Bueso1232e382013-10-08 20:37:16 -0700565 seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700566 seq_puts(m, "\n");
567 }
568}
569
570static void seq_header(struct seq_file *m)
571{
Davidlohr Bueso1232e382013-10-08 20:37:16 -0700572 seq_puts(m, "lock_stat version 0.4\n");
Peter Zijlstra9833f8c2009-02-14 16:59:04 +0100573
574 if (unlikely(!debug_locks))
575 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
576
Davidlohr Bueso1232e382013-10-08 20:37:16 -0700577 seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
578 seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
Peter Zijlstra96645672007-07-19 01:49:00 -0700579 "%14s %14s\n",
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700580 "class name",
Peter Zijlstra96645672007-07-19 01:49:00 -0700581 "con-bounces",
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700582 "contentions",
583 "waittime-min",
584 "waittime-max",
585 "waittime-total",
Davidlohr Bueso1232e382013-10-08 20:37:16 -0700586 "waittime-avg",
Peter Zijlstra96645672007-07-19 01:49:00 -0700587 "acq-bounces",
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700588 "acquisitions",
589 "holdtime-min",
590 "holdtime-max",
Davidlohr Bueso1232e382013-10-08 20:37:16 -0700591 "holdtime-total",
592 "holdtime-avg");
593 seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700594 seq_printf(m, "\n");
595}
596
597static void *ls_start(struct seq_file *m, loff_t *pos)
598{
599 struct lock_stat_seq *data = m->private;
Li Zefan96004bb2009-08-17 13:40:59 +0800600 struct lock_stat_data *iter;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700601
Tim Pepper94c61c02007-10-11 22:11:11 +0200602 if (*pos == 0)
603 return SEQ_START_TOKEN;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700604
Li Zefan96004bb2009-08-17 13:40:59 +0800605 iter = data->stats + (*pos - 1);
606 if (iter >= data->iter_end)
607 iter = NULL;
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700608
Li Zefan96004bb2009-08-17 13:40:59 +0800609 return iter;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700610}
611
612static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
613{
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700614 (*pos)++;
Li Zefan96004bb2009-08-17 13:40:59 +0800615 return ls_start(m, pos);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700616}
617
618static void ls_stop(struct seq_file *m, void *v)
619{
620}
621
622static int ls_show(struct seq_file *m, void *v)
623{
Tim Pepper94c61c02007-10-11 22:11:11 +0200624 if (v == SEQ_START_TOKEN)
625 seq_header(m);
626 else
627 seq_stats(m, v);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700628
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700629 return 0;
630}
631
James Morris88e9d342009-09-22 16:43:43 -0700632static const struct seq_operations lockstat_ops = {
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700633 .start = ls_start,
634 .next = ls_next,
635 .stop = ls_stop,
636 .show = ls_show,
637};
638
639static int lock_stat_open(struct inode *inode, struct file *file)
640{
641 int res;
642 struct lock_class *class;
643 struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
644
645 if (!data)
646 return -ENOMEM;
647
648 res = seq_open(file, &lockstat_ops);
649 if (!res) {
650 struct lock_stat_data *iter = data->stats;
651 struct seq_file *m = file->private_data;
Waiman Longfb7275a2022-02-10 22:55:26 -0500652 unsigned long idx;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700653
Waiman Longfb7275a2022-02-10 22:55:26 -0500654 iterate_lock_classes(idx, class) {
655 if (!test_bit(idx, lock_classes_in_use))
656 continue;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700657 iter->class = class;
658 iter->stats = lock_stats(class);
659 iter++;
660 }
Waiman Longfb7275a2022-02-10 22:55:26 -0500661
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700662 data->iter_end = iter;
663
Li Zefan96004bb2009-08-17 13:40:59 +0800664 sort(data->stats, data->iter_end - data->stats,
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700665 sizeof(struct lock_stat_data),
666 lock_stat_cmp, NULL);
667
668 m->private = data;
669 } else
670 vfree(data);
671
672 return res;
673}
674
675static ssize_t lock_stat_write(struct file *file, const char __user *buf,
676 size_t count, loff_t *ppos)
677{
678 struct lock_class *class;
Waiman Longfb7275a2022-02-10 22:55:26 -0500679 unsigned long idx;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700680 char c;
681
682 if (count) {
683 if (get_user(c, buf))
684 return -EFAULT;
685
686 if (c != '0')
687 return count;
688
Waiman Longfb7275a2022-02-10 22:55:26 -0500689 iterate_lock_classes(idx, class) {
690 if (!test_bit(idx, lock_classes_in_use))
691 continue;
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700692 clear_lock_stats(class);
Waiman Longfb7275a2022-02-10 22:55:26 -0500693 }
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700694 }
695 return count;
696}
697
698static int lock_stat_release(struct inode *inode, struct file *file)
699{
700 struct seq_file *seq = file->private_data;
701
702 vfree(seq->private);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700703 return seq_release(inode, file);
704}
705
Alexey Dobriyan97a32532020-02-03 17:37:17 -0800706static const struct proc_ops lock_stat_proc_ops = {
707 .proc_open = lock_stat_open,
708 .proc_write = lock_stat_write,
709 .proc_read = seq_read,
710 .proc_lseek = seq_lseek,
711 .proc_release = lock_stat_release,
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700712};
713#endif /* CONFIG_LOCK_STAT */
714
Ingo Molnara8f24a32006-07-03 00:24:52 -0700715static int __init lockdep_proc_init(void)
716{
Christoph Hellwigfddda2b2018-04-13 19:44:18 +0200717 proc_create_seq("lockdep", S_IRUSR, NULL, &lockdep_ops);
Huang, Yingcd1a28e2008-06-23 11:20:54 +0800718#ifdef CONFIG_PROVE_LOCKING
Christoph Hellwigfddda2b2018-04-13 19:44:18 +0200719 proc_create_seq("lockdep_chains", S_IRUSR, NULL, &lockdep_chains_ops);
Huang, Yingcd1a28e2008-06-23 11:20:54 +0800720#endif
Christoph Hellwig3f3942a2018-05-15 15:57:23 +0200721 proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700722#ifdef CONFIG_LOCK_STAT
Alexey Dobriyan97a32532020-02-03 17:37:17 -0800723 proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, &lock_stat_proc_ops);
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700724#endif
725
Ingo Molnara8f24a32006-07-03 00:24:52 -0700726 return 0;
727}
728
729__initcall(lockdep_proc_init);
730