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Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001/*
2 * kernel/lockdep.c
3 *
4 * Runtime locking correctness validator
5 *
6 * Started by Ingo Molnar:
7 *
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -07008 * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9 * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070010 *
11 * this code maps all the lock dependencies as they occur in a live kernel
12 * and will warn about the following classes of locking bugs:
13 *
14 * - lock inversion scenarios
15 * - circular lock dependencies
16 * - hardirq/softirq safe/unsafe locking bugs
17 *
18 * Bugs are reported even if the current locking scenario does not cause
19 * any deadlock at this point.
20 *
21 * I.e. if anytime in the past two locks were taken in a different order,
22 * even if it happened for another task, even if those were different
23 * locks (but of the same class as this lock), this code will detect it.
24 *
25 * Thanks to Arjan van de Ven for coming up with the initial idea of
26 * mapping lock dependencies runtime.
27 */
Steven Rostedta5e25882008-12-02 15:34:05 -050028#define DISABLE_BRANCH_PROFILING
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070029#include <linux/mutex.h>
30#include <linux/sched.h>
31#include <linux/delay.h>
32#include <linux/module.h>
33#include <linux/proc_fs.h>
34#include <linux/seq_file.h>
35#include <linux/spinlock.h>
36#include <linux/kallsyms.h>
37#include <linux/interrupt.h>
38#include <linux/stacktrace.h>
39#include <linux/debug_locks.h>
40#include <linux/irqflags.h>
Dave Jones99de0552006-09-29 02:00:10 -070041#include <linux/utsname.h>
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -070042#include <linux/hash.h>
Steven Rostedt81d68a92008-05-12 21:20:42 +020043#include <linux/ftrace.h>
Peter Zijlstrab4b136f2009-01-29 14:50:36 +010044#include <linux/stringify.h>
Ming Leid588e462009-07-16 15:44:29 +020045#include <linux/bitops.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090046#include <linux/gfp.h>
Peter Zijlstraaf012962009-07-16 15:44:29 +020047
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070048#include <asm/sections.h>
49
50#include "lockdep_internals.h"
51
Steven Rostedta8d154b2009-04-10 09:36:00 -040052#define CREATE_TRACE_POINTS
Frederic Weisbecker67178762009-11-13 10:06:34 +010053#include <trace/events/lock.h>
Steven Rostedta8d154b2009-04-10 09:36:00 -040054
Peter Zijlstraf20786f2007-07-19 01:48:56 -070055#ifdef CONFIG_PROVE_LOCKING
56int prove_locking = 1;
57module_param(prove_locking, int, 0644);
58#else
59#define prove_locking 0
60#endif
61
62#ifdef CONFIG_LOCK_STAT
63int lock_stat = 1;
64module_param(lock_stat, int, 0644);
65#else
66#define lock_stat 0
67#endif
68
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070069/*
Ingo Molnar74c383f2006-12-13 00:34:43 -080070 * lockdep_lock: protects the lockdep graph, the hashes and the
71 * class/list/hash allocators.
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070072 *
73 * This is one of the rare exceptions where it's justified
74 * to use a raw spinlock - we really dont want the spinlock
Ingo Molnar74c383f2006-12-13 00:34:43 -080075 * code to recurse back into the lockdep code...
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070076 */
Thomas Gleixneredc35bd2009-12-03 12:38:57 +010077static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
Ingo Molnar74c383f2006-12-13 00:34:43 -080078
79static int graph_lock(void)
80{
Thomas Gleixner0199c4e2009-12-02 20:01:25 +010081 arch_spin_lock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -080082 /*
83 * Make sure that if another CPU detected a bug while
84 * walking the graph we dont change it (while the other
85 * CPU is busy printing out stuff with the graph lock
86 * dropped already)
87 */
88 if (!debug_locks) {
Thomas Gleixner0199c4e2009-12-02 20:01:25 +010089 arch_spin_unlock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -080090 return 0;
91 }
Steven Rostedtbb065af2008-05-12 21:21:00 +020092 /* prevent any recursions within lockdep from causing deadlocks */
93 current->lockdep_recursion++;
Ingo Molnar74c383f2006-12-13 00:34:43 -080094 return 1;
95}
96
97static inline int graph_unlock(void)
98{
Thomas Gleixner0199c4e2009-12-02 20:01:25 +010099 if (debug_locks && !arch_spin_is_locked(&lockdep_lock))
Jarek Poplawski381a2292007-02-10 01:44:58 -0800100 return DEBUG_LOCKS_WARN_ON(1);
101
Steven Rostedtbb065af2008-05-12 21:21:00 +0200102 current->lockdep_recursion--;
Thomas Gleixner0199c4e2009-12-02 20:01:25 +0100103 arch_spin_unlock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800104 return 0;
105}
106
107/*
108 * Turn lock debugging off and return with 0 if it was off already,
109 * and also release the graph lock:
110 */
111static inline int debug_locks_off_graph_unlock(void)
112{
113 int ret = debug_locks_off();
114
Thomas Gleixner0199c4e2009-12-02 20:01:25 +0100115 arch_spin_unlock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800116
117 return ret;
118}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700119
120static int lockdep_initialized;
121
122unsigned long nr_list_entries;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200123static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700124
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700125/*
126 * All data structures here are protected by the global debug_lock.
127 *
128 * Mutex key structs only get allocated, once during bootup, and never
129 * get freed - this significantly simplifies the debugging code.
130 */
131unsigned long nr_lock_classes;
132static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
133
Dave Jonesf82b2172008-08-11 09:30:23 +0200134static inline struct lock_class *hlock_class(struct held_lock *hlock)
135{
136 if (!hlock->class_idx) {
137 DEBUG_LOCKS_WARN_ON(1);
138 return NULL;
139 }
140 return lock_classes + hlock->class_idx - 1;
141}
142
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700143#ifdef CONFIG_LOCK_STAT
Tejun Heo1871e522009-10-29 22:34:13 +0900144static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS],
145 cpu_lock_stats);
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700146
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200147static inline u64 lockstat_clock(void)
148{
Peter Zijlstrac6763292010-05-25 10:48:51 +0200149 return local_clock();
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200150}
151
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200152static int lock_point(unsigned long points[], unsigned long ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700153{
154 int i;
155
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200156 for (i = 0; i < LOCKSTAT_POINTS; i++) {
157 if (points[i] == 0) {
158 points[i] = ip;
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700159 break;
160 }
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200161 if (points[i] == ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700162 break;
163 }
164
165 return i;
166}
167
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200168static void lock_time_inc(struct lock_time *lt, u64 time)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700169{
170 if (time > lt->max)
171 lt->max = time;
172
Frank Rowand109d71c2009-11-19 13:42:06 -0800173 if (time < lt->min || !lt->nr)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700174 lt->min = time;
175
176 lt->total += time;
177 lt->nr++;
178}
179
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700180static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
181{
Frank Rowand109d71c2009-11-19 13:42:06 -0800182 if (!src->nr)
183 return;
184
185 if (src->max > dst->max)
186 dst->max = src->max;
187
188 if (src->min < dst->min || !dst->nr)
189 dst->min = src->min;
190
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700191 dst->total += src->total;
192 dst->nr += src->nr;
193}
194
195struct lock_class_stats lock_stats(struct lock_class *class)
196{
197 struct lock_class_stats stats;
198 int cpu, i;
199
200 memset(&stats, 0, sizeof(struct lock_class_stats));
201 for_each_possible_cpu(cpu) {
202 struct lock_class_stats *pcs =
Tejun Heo1871e522009-10-29 22:34:13 +0900203 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700204
205 for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
206 stats.contention_point[i] += pcs->contention_point[i];
207
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200208 for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
209 stats.contending_point[i] += pcs->contending_point[i];
210
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700211 lock_time_add(&pcs->read_waittime, &stats.read_waittime);
212 lock_time_add(&pcs->write_waittime, &stats.write_waittime);
213
214 lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
215 lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
Peter Zijlstra96645672007-07-19 01:49:00 -0700216
217 for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
218 stats.bounces[i] += pcs->bounces[i];
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700219 }
220
221 return stats;
222}
223
224void clear_lock_stats(struct lock_class *class)
225{
226 int cpu;
227
228 for_each_possible_cpu(cpu) {
229 struct lock_class_stats *cpu_stats =
Tejun Heo1871e522009-10-29 22:34:13 +0900230 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700231
232 memset(cpu_stats, 0, sizeof(struct lock_class_stats));
233 }
234 memset(class->contention_point, 0, sizeof(class->contention_point));
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200235 memset(class->contending_point, 0, sizeof(class->contending_point));
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700236}
237
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700238static struct lock_class_stats *get_lock_stats(struct lock_class *class)
239{
Tejun Heo1871e522009-10-29 22:34:13 +0900240 return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700241}
242
243static void put_lock_stats(struct lock_class_stats *stats)
244{
Tejun Heo1871e522009-10-29 22:34:13 +0900245 put_cpu_var(cpu_lock_stats);
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700246}
247
248static void lock_release_holdtime(struct held_lock *hlock)
249{
250 struct lock_class_stats *stats;
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200251 u64 holdtime;
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700252
253 if (!lock_stat)
254 return;
255
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200256 holdtime = lockstat_clock() - hlock->holdtime_stamp;
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700257
Dave Jonesf82b2172008-08-11 09:30:23 +0200258 stats = get_lock_stats(hlock_class(hlock));
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700259 if (hlock->read)
260 lock_time_inc(&stats->read_holdtime, holdtime);
261 else
262 lock_time_inc(&stats->write_holdtime, holdtime);
263 put_lock_stats(stats);
264}
265#else
266static inline void lock_release_holdtime(struct held_lock *hlock)
267{
268}
269#endif
270
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700271/*
272 * We keep a global list of all lock classes. The list only grows,
273 * never shrinks. The list is only accessed with the lockdep
274 * spinlock lock held.
275 */
276LIST_HEAD(all_lock_classes);
277
278/*
279 * The lockdep classes are in a hash-table as well, for fast lookup:
280 */
281#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
282#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700283#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700284#define classhashentry(key) (classhash_table + __classhashfn((key)))
285
286static struct list_head classhash_table[CLASSHASH_SIZE];
287
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700288/*
289 * We put the lock dependency chains into a hash-table as well, to cache
290 * their existence:
291 */
292#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
293#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700294#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700295#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
296
297static struct list_head chainhash_table[CHAINHASH_SIZE];
298
299/*
300 * The hash key of the lock dependency chains is a hash itself too:
301 * it's a hash of all locks taken up to that lock, including that lock.
302 * It's a 64-bit hash, because it's important for the keys to be
303 * unique.
304 */
305#define iterate_chain_key(key1, key2) \
Ingo Molnar03cbc352006-09-29 02:01:46 -0700306 (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
307 ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700308 (key2))
309
Steven Rostedt1d09daa2008-05-12 21:20:55 +0200310void lockdep_off(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700311{
312 current->lockdep_recursion++;
313}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700314EXPORT_SYMBOL(lockdep_off);
315
Steven Rostedt1d09daa2008-05-12 21:20:55 +0200316void lockdep_on(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700317{
318 current->lockdep_recursion--;
319}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700320EXPORT_SYMBOL(lockdep_on);
321
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700322/*
323 * Debugging switches:
324 */
325
326#define VERBOSE 0
Ingo Molnar33e94e92006-12-13 00:34:41 -0800327#define VERY_VERBOSE 0
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700328
329#if VERBOSE
330# define HARDIRQ_VERBOSE 1
331# define SOFTIRQ_VERBOSE 1
Nick Piggincf40bd12009-01-21 08:12:39 +0100332# define RECLAIM_VERBOSE 1
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700333#else
334# define HARDIRQ_VERBOSE 0
335# define SOFTIRQ_VERBOSE 0
Nick Piggincf40bd12009-01-21 08:12:39 +0100336# define RECLAIM_VERBOSE 0
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700337#endif
338
Nick Piggincf40bd12009-01-21 08:12:39 +0100339#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700340/*
341 * Quick filtering for interesting events:
342 */
343static int class_filter(struct lock_class *class)
344{
Andi Kleenf9829cc2006-07-10 04:44:01 -0700345#if 0
346 /* Example */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700347 if (class->name_version == 1 &&
Andi Kleenf9829cc2006-07-10 04:44:01 -0700348 !strcmp(class->name, "lockname"))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700349 return 1;
350 if (class->name_version == 1 &&
Andi Kleenf9829cc2006-07-10 04:44:01 -0700351 !strcmp(class->name, "&struct->lockfield"))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700352 return 1;
Andi Kleenf9829cc2006-07-10 04:44:01 -0700353#endif
Ingo Molnara6640892006-12-13 00:34:39 -0800354 /* Filter everything else. 1 would be to allow everything else */
355 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700356}
357#endif
358
359static int verbose(struct lock_class *class)
360{
361#if VERBOSE
362 return class_filter(class);
363#endif
364 return 0;
365}
366
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700367/*
368 * Stack-trace: tightly packed array of stack backtrace
Ingo Molnar74c383f2006-12-13 00:34:43 -0800369 * addresses. Protected by the graph_lock.
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700370 */
371unsigned long nr_stack_trace_entries;
372static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
373
374static int save_trace(struct stack_trace *trace)
375{
376 trace->nr_entries = 0;
377 trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
378 trace->entries = stack_trace + nr_stack_trace_entries;
379
Andi Kleen5a1b3992006-09-26 10:52:34 +0200380 trace->skip = 3;
Andi Kleen5a1b3992006-09-26 10:52:34 +0200381
Christoph Hellwigab1b6f02007-05-08 00:23:29 -0700382 save_stack_trace(trace);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700383
Peter Zijlstra4f84f432009-07-20 15:27:04 +0200384 /*
385 * Some daft arches put -1 at the end to indicate its a full trace.
386 *
387 * <rant> this is buggy anyway, since it takes a whole extra entry so a
388 * complete trace that maxes out the entries provided will be reported
389 * as incomplete, friggin useless </rant>
390 */
Luck, Tonyea5b41f2009-12-09 14:29:36 -0800391 if (trace->nr_entries != 0 &&
392 trace->entries[trace->nr_entries-1] == ULONG_MAX)
Peter Zijlstra4f84f432009-07-20 15:27:04 +0200393 trace->nr_entries--;
394
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700395 trace->max_entries = trace->nr_entries;
396
397 nr_stack_trace_entries += trace->nr_entries;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700398
Peter Zijlstra4f84f432009-07-20 15:27:04 +0200399 if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
Ingo Molnar74c383f2006-12-13 00:34:43 -0800400 if (!debug_locks_off_graph_unlock())
401 return 0;
402
403 printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
404 printk("turning off the locking correctness validator.\n");
405 dump_stack();
406
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700407 return 0;
408 }
409
410 return 1;
411}
412
413unsigned int nr_hardirq_chains;
414unsigned int nr_softirq_chains;
415unsigned int nr_process_chains;
416unsigned int max_lockdep_depth;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700417
418#ifdef CONFIG_DEBUG_LOCKDEP
419/*
420 * We cannot printk in early bootup code. Not even early_printk()
421 * might work. So we mark any initialization errors and printk
422 * about it later on, in lockdep_info().
423 */
424static int lockdep_init_error;
Johannes Bergc71063c2007-07-19 01:49:02 -0700425static unsigned long lockdep_init_trace_data[20];
426static struct stack_trace lockdep_init_trace = {
427 .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
428 .entries = lockdep_init_trace_data,
429};
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700430
431/*
432 * Various lockdep statistics:
433 */
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200434DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700435#endif
436
437/*
438 * Locking printouts:
439 */
440
Peter Zijlstrafabe9c42009-01-22 14:51:01 +0100441#define __USAGE(__STATE) \
Peter Zijlstrab4b136f2009-01-29 14:50:36 +0100442 [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
443 [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
444 [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
445 [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
Peter Zijlstrafabe9c42009-01-22 14:51:01 +0100446
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700447static const char *usage_str[] =
448{
Peter Zijlstrafabe9c42009-01-22 14:51:01 +0100449#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
450#include "lockdep_states.h"
451#undef LOCKDEP_STATE
452 [LOCK_USED] = "INITIAL USE",
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700453};
454
455const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
456{
Alexey Dobriyanffb45122007-05-08 00:28:41 -0700457 return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700458}
459
Peter Zijlstra3ff176c2009-01-22 17:40:42 +0100460static inline unsigned long lock_flag(enum lock_usage_bit bit)
461{
462 return 1UL << bit;
463}
464
465static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
466{
467 char c = '.';
468
469 if (class->usage_mask & lock_flag(bit + 2))
470 c = '+';
471 if (class->usage_mask & lock_flag(bit)) {
472 c = '-';
473 if (class->usage_mask & lock_flag(bit + 2))
474 c = '?';
475 }
476
477 return c;
478}
479
Peter Zijlstraf510b232009-01-22 17:53:47 +0100480void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700481{
Peter Zijlstraf510b232009-01-22 17:53:47 +0100482 int i = 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700483
Peter Zijlstraf510b232009-01-22 17:53:47 +0100484#define LOCKDEP_STATE(__STATE) \
485 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
486 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
487#include "lockdep_states.h"
488#undef LOCKDEP_STATE
489
490 usage[i] = '\0';
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700491}
492
Steven Rostedt3003eba2011-04-20 21:41:54 -0400493static int __print_lock_name(struct lock_class *class)
494{
495 char str[KSYM_NAME_LEN];
496 const char *name;
497
498 name = class->name;
499 if (!name)
500 name = __get_key_name(class->key, str);
501
502 return printk("%s", name);
503}
504
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700505static void print_lock_name(struct lock_class *class)
506{
Peter Zijlstraf510b232009-01-22 17:53:47 +0100507 char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS];
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700508 const char *name;
509
Peter Zijlstraf510b232009-01-22 17:53:47 +0100510 get_usage_chars(class, usage);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700511
512 name = class->name;
513 if (!name) {
514 name = __get_key_name(class->key, str);
515 printk(" (%s", name);
516 } else {
517 printk(" (%s", name);
518 if (class->name_version > 1)
519 printk("#%d", class->name_version);
520 if (class->subclass)
521 printk("/%d", class->subclass);
522 }
Peter Zijlstraf510b232009-01-22 17:53:47 +0100523 printk("){%s}", usage);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700524}
525
526static void print_lockdep_cache(struct lockdep_map *lock)
527{
528 const char *name;
Tejun Heo9281ace2007-07-17 04:03:51 -0700529 char str[KSYM_NAME_LEN];
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700530
531 name = lock->name;
532 if (!name)
533 name = __get_key_name(lock->key->subkeys, str);
534
535 printk("%s", name);
536}
537
538static void print_lock(struct held_lock *hlock)
539{
Dave Jonesf82b2172008-08-11 09:30:23 +0200540 print_lock_name(hlock_class(hlock));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700541 printk(", at: ");
542 print_ip_sym(hlock->acquire_ip);
543}
544
545static void lockdep_print_held_locks(struct task_struct *curr)
546{
547 int i, depth = curr->lockdep_depth;
548
549 if (!depth) {
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -0700550 printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700551 return;
552 }
553 printk("%d lock%s held by %s/%d:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -0700554 depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700555
556 for (i = 0; i < depth; i++) {
557 printk(" #%d: ", i);
558 print_lock(curr->held_locks + i);
559 }
560}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700561
Dave Jones99de0552006-09-29 02:00:10 -0700562static void print_kernel_version(void)
563{
Serge E. Hallyn96b644b2006-10-02 02:18:13 -0700564 printk("%s %.*s\n", init_utsname()->release,
565 (int)strcspn(init_utsname()->version, " "),
566 init_utsname()->version);
Dave Jones99de0552006-09-29 02:00:10 -0700567}
568
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700569static int very_verbose(struct lock_class *class)
570{
571#if VERY_VERBOSE
572 return class_filter(class);
573#endif
574 return 0;
575}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700576
577/*
578 * Is this the address of a static object:
579 */
580static int static_obj(void *obj)
581{
582 unsigned long start = (unsigned long) &_stext,
583 end = (unsigned long) &_end,
584 addr = (unsigned long) obj;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700585
586 /*
587 * static variable?
588 */
589 if ((addr >= start) && (addr < end))
590 return 1;
591
Mike Frysinger2a9ad182009-09-22 16:44:16 -0700592 if (arch_is_kernel_data(addr))
593 return 1;
594
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700595 /*
Tejun Heo10fad5e2010-03-10 18:57:54 +0900596 * in-kernel percpu var?
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700597 */
Tejun Heo10fad5e2010-03-10 18:57:54 +0900598 if (is_kernel_percpu_address(addr))
599 return 1;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700600
601 /*
Tejun Heo10fad5e2010-03-10 18:57:54 +0900602 * module static or percpu var?
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700603 */
Tejun Heo10fad5e2010-03-10 18:57:54 +0900604 return is_module_address(addr) || is_module_percpu_address(addr);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700605}
606
607/*
608 * To make lock name printouts unique, we calculate a unique
609 * class->name_version generation counter:
610 */
611static int count_matching_names(struct lock_class *new_class)
612{
613 struct lock_class *class;
614 int count = 0;
615
616 if (!new_class->name)
617 return 0;
618
619 list_for_each_entry(class, &all_lock_classes, lock_entry) {
620 if (new_class->key - new_class->subclass == class->key)
621 return class->name_version;
622 if (class->name && !strcmp(class->name, new_class->name))
623 count = max(count, class->name_version);
624 }
625
626 return count + 1;
627}
628
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700629/*
630 * Register a lock's class in the hash-table, if the class is not present
631 * yet. Otherwise we look it up. We cache the result in the lock object
632 * itself, so actual lookup of the hash should be once per lock object.
633 */
634static inline struct lock_class *
Ingo Molnard6d897c2006-07-10 04:44:04 -0700635look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700636{
637 struct lockdep_subclass_key *key;
638 struct list_head *hash_head;
639 struct lock_class *class;
640
641#ifdef CONFIG_DEBUG_LOCKDEP
642 /*
643 * If the architecture calls into lockdep before initializing
644 * the hashes then we'll warn about it later. (we cannot printk
645 * right now)
646 */
647 if (unlikely(!lockdep_initialized)) {
648 lockdep_init();
649 lockdep_init_error = 1;
Johannes Bergc71063c2007-07-19 01:49:02 -0700650 save_stack_trace(&lockdep_init_trace);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700651 }
652#endif
653
Hitoshi Mitake4ba053c2010-10-13 17:30:26 +0900654 if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
655 debug_locks_off();
656 printk(KERN_ERR
657 "BUG: looking up invalid subclass: %u\n", subclass);
658 printk(KERN_ERR
659 "turning off the locking correctness validator.\n");
660 dump_stack();
661 return NULL;
662 }
663
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700664 /*
665 * Static locks do not have their class-keys yet - for them the key
666 * is the lock object itself:
667 */
668 if (unlikely(!lock->key))
669 lock->key = (void *)lock;
670
671 /*
672 * NOTE: the class-key must be unique. For dynamic locks, a static
673 * lock_class_key variable is passed in through the mutex_init()
674 * (or spin_lock_init()) call - which acts as the key. For static
675 * locks we use the lock object itself as the key.
676 */
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700677 BUILD_BUG_ON(sizeof(struct lock_class_key) >
678 sizeof(struct lockdep_map));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700679
680 key = lock->key->subkeys + subclass;
681
682 hash_head = classhashentry(key);
683
684 /*
685 * We can walk the hash lockfree, because the hash only
686 * grows, and we are careful when adding entries to the end:
687 */
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700688 list_for_each_entry(class, hash_head, hash_entry) {
689 if (class->key == key) {
690 WARN_ON_ONCE(class->name != lock->name);
Ingo Molnard6d897c2006-07-10 04:44:04 -0700691 return class;
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700692 }
693 }
Ingo Molnard6d897c2006-07-10 04:44:04 -0700694
695 return NULL;
696}
697
698/*
699 * Register a lock's class in the hash-table, if the class is not present
700 * yet. Otherwise we look it up. We cache the result in the lock object
701 * itself, so actual lookup of the hash should be once per lock object.
702 */
703static inline struct lock_class *
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -0400704register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
Ingo Molnard6d897c2006-07-10 04:44:04 -0700705{
706 struct lockdep_subclass_key *key;
707 struct list_head *hash_head;
708 struct lock_class *class;
Ingo Molnar70e45062006-12-06 20:40:50 -0800709 unsigned long flags;
Ingo Molnard6d897c2006-07-10 04:44:04 -0700710
711 class = look_up_lock_class(lock, subclass);
712 if (likely(class))
713 return class;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700714
715 /*
716 * Debug-check: all keys must be persistent!
717 */
718 if (!static_obj(lock->key)) {
719 debug_locks_off();
720 printk("INFO: trying to register non-static key.\n");
721 printk("the code is fine but needs lockdep annotation.\n");
722 printk("turning off the locking correctness validator.\n");
723 dump_stack();
724
725 return NULL;
726 }
727
Ingo Molnard6d897c2006-07-10 04:44:04 -0700728 key = lock->key->subkeys + subclass;
729 hash_head = classhashentry(key);
730
Ingo Molnar70e45062006-12-06 20:40:50 -0800731 raw_local_irq_save(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800732 if (!graph_lock()) {
733 raw_local_irq_restore(flags);
734 return NULL;
735 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700736 /*
737 * We have to do the hash-walk again, to avoid races
738 * with another CPU:
739 */
740 list_for_each_entry(class, hash_head, hash_entry)
741 if (class->key == key)
742 goto out_unlock_set;
743 /*
744 * Allocate a new key from the static array, and add it to
745 * the hash:
746 */
747 if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
Ingo Molnar74c383f2006-12-13 00:34:43 -0800748 if (!debug_locks_off_graph_unlock()) {
749 raw_local_irq_restore(flags);
750 return NULL;
751 }
Ingo Molnar70e45062006-12-06 20:40:50 -0800752 raw_local_irq_restore(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800753
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700754 printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
755 printk("turning off the locking correctness validator.\n");
Peter Zijlstraeedeeab2009-03-18 12:38:47 +0100756 dump_stack();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700757 return NULL;
758 }
759 class = lock_classes + nr_lock_classes++;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200760 debug_atomic_inc(nr_unused_locks);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700761 class->key = key;
762 class->name = lock->name;
763 class->subclass = subclass;
764 INIT_LIST_HEAD(&class->lock_entry);
765 INIT_LIST_HEAD(&class->locks_before);
766 INIT_LIST_HEAD(&class->locks_after);
767 class->name_version = count_matching_names(class);
768 /*
769 * We use RCU's safe list-add method to make
770 * parallel walking of the hash-list safe:
771 */
772 list_add_tail_rcu(&class->hash_entry, hash_head);
Dale Farnsworth14811972008-02-25 23:03:02 +0100773 /*
774 * Add it to the global list of classes:
775 */
776 list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700777
778 if (verbose(class)) {
Ingo Molnar74c383f2006-12-13 00:34:43 -0800779 graph_unlock();
Ingo Molnar70e45062006-12-06 20:40:50 -0800780 raw_local_irq_restore(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800781
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700782 printk("\nnew class %p: %s", class->key, class->name);
783 if (class->name_version > 1)
784 printk("#%d", class->name_version);
785 printk("\n");
786 dump_stack();
Ingo Molnar74c383f2006-12-13 00:34:43 -0800787
Ingo Molnar70e45062006-12-06 20:40:50 -0800788 raw_local_irq_save(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800789 if (!graph_lock()) {
790 raw_local_irq_restore(flags);
791 return NULL;
792 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700793 }
794out_unlock_set:
Ingo Molnar74c383f2006-12-13 00:34:43 -0800795 graph_unlock();
Ingo Molnar70e45062006-12-06 20:40:50 -0800796 raw_local_irq_restore(flags);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700797
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -0400798 if (!subclass || force)
Hitoshi Mitake62016252010-10-05 18:01:51 +0900799 lock->class_cache[0] = class;
800 else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
801 lock->class_cache[subclass] = class;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700802
Jarek Poplawski381a2292007-02-10 01:44:58 -0800803 if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
804 return NULL;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700805
806 return class;
807}
808
Peter Zijlstraca58abc2007-07-19 01:48:53 -0700809#ifdef CONFIG_PROVE_LOCKING
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700810/*
Peter Zijlstra8e182572007-07-19 01:48:54 -0700811 * Allocate a lockdep entry. (assumes the graph_lock held, returns
812 * with NULL on failure)
813 */
814static struct lock_list *alloc_list_entry(void)
815{
816 if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
817 if (!debug_locks_off_graph_unlock())
818 return NULL;
819
820 printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
821 printk("turning off the locking correctness validator.\n");
Peter Zijlstraeedeeab2009-03-18 12:38:47 +0100822 dump_stack();
Peter Zijlstra8e182572007-07-19 01:48:54 -0700823 return NULL;
824 }
825 return list_entries + nr_list_entries++;
826}
827
828/*
829 * Add a new dependency to the head of the list:
830 */
831static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
Yong Zhang4726f2a2010-05-04 14:16:48 +0800832 struct list_head *head, unsigned long ip,
833 int distance, struct stack_trace *trace)
Peter Zijlstra8e182572007-07-19 01:48:54 -0700834{
835 struct lock_list *entry;
836 /*
837 * Lock not present yet - get a new dependency struct and
838 * add it to the list:
839 */
840 entry = alloc_list_entry();
841 if (!entry)
842 return 0;
843
Zhu Yi74870172008-08-27 14:33:00 +0800844 entry->class = this;
845 entry->distance = distance;
Yong Zhang4726f2a2010-05-04 14:16:48 +0800846 entry->trace = *trace;
Peter Zijlstra8e182572007-07-19 01:48:54 -0700847 /*
848 * Since we never remove from the dependency list, the list can
849 * be walked lockless by other CPUs, it's only allocation
850 * that must be protected by the spinlock. But this also means
851 * we must make new entries visible only once writes to the
852 * entry become visible - hence the RCU op:
853 */
854 list_add_tail_rcu(&entry->entry, head);
855
856 return 1;
857}
858
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200859/*
860 * For good efficiency of modular, we use power of 2
861 */
Peter Zijlstraaf012962009-07-16 15:44:29 +0200862#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
863#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
864
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200865/*
866 * The circular_queue and helpers is used to implement the
Peter Zijlstraaf012962009-07-16 15:44:29 +0200867 * breadth-first search(BFS)algorithem, by which we can build
868 * the shortest path from the next lock to be acquired to the
869 * previous held lock if there is a circular between them.
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200870 */
Peter Zijlstraaf012962009-07-16 15:44:29 +0200871struct circular_queue {
872 unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
873 unsigned int front, rear;
874};
875
876static struct circular_queue lock_cq;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200877
Ming Lei12f3dfd2009-07-16 15:44:29 +0200878unsigned int max_bfs_queue_depth;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200879
Ming Leie351b662009-07-22 22:48:09 +0800880static unsigned int lockdep_dependency_gen_id;
881
Peter Zijlstraaf012962009-07-16 15:44:29 +0200882static inline void __cq_init(struct circular_queue *cq)
883{
884 cq->front = cq->rear = 0;
Ming Leie351b662009-07-22 22:48:09 +0800885 lockdep_dependency_gen_id++;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200886}
887
888static inline int __cq_empty(struct circular_queue *cq)
889{
890 return (cq->front == cq->rear);
891}
892
893static inline int __cq_full(struct circular_queue *cq)
894{
895 return ((cq->rear + 1) & CQ_MASK) == cq->front;
896}
897
898static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
899{
900 if (__cq_full(cq))
901 return -1;
902
903 cq->element[cq->rear] = elem;
904 cq->rear = (cq->rear + 1) & CQ_MASK;
905 return 0;
906}
907
908static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
909{
910 if (__cq_empty(cq))
911 return -1;
912
913 *elem = cq->element[cq->front];
914 cq->front = (cq->front + 1) & CQ_MASK;
915 return 0;
916}
917
918static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
919{
920 return (cq->rear - cq->front) & CQ_MASK;
921}
922
923static inline void mark_lock_accessed(struct lock_list *lock,
924 struct lock_list *parent)
925{
926 unsigned long nr;
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200927
Peter Zijlstraaf012962009-07-16 15:44:29 +0200928 nr = lock - list_entries;
929 WARN_ON(nr >= nr_list_entries);
930 lock->parent = parent;
Ming Leie351b662009-07-22 22:48:09 +0800931 lock->class->dep_gen_id = lockdep_dependency_gen_id;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200932}
933
934static inline unsigned long lock_accessed(struct lock_list *lock)
935{
936 unsigned long nr;
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200937
Peter Zijlstraaf012962009-07-16 15:44:29 +0200938 nr = lock - list_entries;
939 WARN_ON(nr >= nr_list_entries);
Ming Leie351b662009-07-22 22:48:09 +0800940 return lock->class->dep_gen_id == lockdep_dependency_gen_id;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200941}
942
943static inline struct lock_list *get_lock_parent(struct lock_list *child)
944{
945 return child->parent;
946}
947
948static inline int get_lock_depth(struct lock_list *child)
949{
950 int depth = 0;
951 struct lock_list *parent;
952
953 while ((parent = get_lock_parent(child))) {
954 child = parent;
955 depth++;
956 }
957 return depth;
958}
959
Ming Lei9e2d5512009-07-16 15:44:29 +0200960static int __bfs(struct lock_list *source_entry,
Peter Zijlstraaf012962009-07-16 15:44:29 +0200961 void *data,
962 int (*match)(struct lock_list *entry, void *data),
963 struct lock_list **target_entry,
964 int forward)
Ming Leic94aa5c2009-07-16 15:44:29 +0200965{
966 struct lock_list *entry;
Ming Leid588e462009-07-16 15:44:29 +0200967 struct list_head *head;
Ming Leic94aa5c2009-07-16 15:44:29 +0200968 struct circular_queue *cq = &lock_cq;
969 int ret = 1;
970
Ming Lei9e2d5512009-07-16 15:44:29 +0200971 if (match(source_entry, data)) {
Ming Leic94aa5c2009-07-16 15:44:29 +0200972 *target_entry = source_entry;
973 ret = 0;
974 goto exit;
975 }
976
Ming Leid588e462009-07-16 15:44:29 +0200977 if (forward)
978 head = &source_entry->class->locks_after;
979 else
980 head = &source_entry->class->locks_before;
981
982 if (list_empty(head))
983 goto exit;
984
985 __cq_init(cq);
Ming Leic94aa5c2009-07-16 15:44:29 +0200986 __cq_enqueue(cq, (unsigned long)source_entry);
987
988 while (!__cq_empty(cq)) {
989 struct lock_list *lock;
Ming Leic94aa5c2009-07-16 15:44:29 +0200990
991 __cq_dequeue(cq, (unsigned long *)&lock);
992
993 if (!lock->class) {
994 ret = -2;
995 goto exit;
996 }
997
998 if (forward)
999 head = &lock->class->locks_after;
1000 else
1001 head = &lock->class->locks_before;
1002
1003 list_for_each_entry(entry, head, entry) {
1004 if (!lock_accessed(entry)) {
Ming Lei12f3dfd2009-07-16 15:44:29 +02001005 unsigned int cq_depth;
Ming Leic94aa5c2009-07-16 15:44:29 +02001006 mark_lock_accessed(entry, lock);
Ming Lei9e2d5512009-07-16 15:44:29 +02001007 if (match(entry, data)) {
Ming Leic94aa5c2009-07-16 15:44:29 +02001008 *target_entry = entry;
1009 ret = 0;
1010 goto exit;
1011 }
1012
1013 if (__cq_enqueue(cq, (unsigned long)entry)) {
1014 ret = -1;
1015 goto exit;
1016 }
Ming Lei12f3dfd2009-07-16 15:44:29 +02001017 cq_depth = __cq_get_elem_count(cq);
1018 if (max_bfs_queue_depth < cq_depth)
1019 max_bfs_queue_depth = cq_depth;
Ming Leic94aa5c2009-07-16 15:44:29 +02001020 }
1021 }
1022 }
1023exit:
1024 return ret;
1025}
1026
Ming Leid7aaba12009-07-16 15:44:29 +02001027static inline int __bfs_forwards(struct lock_list *src_entry,
Ming Lei9e2d5512009-07-16 15:44:29 +02001028 void *data,
1029 int (*match)(struct lock_list *entry, void *data),
1030 struct lock_list **target_entry)
Ming Leic94aa5c2009-07-16 15:44:29 +02001031{
Ming Lei9e2d5512009-07-16 15:44:29 +02001032 return __bfs(src_entry, data, match, target_entry, 1);
Ming Leic94aa5c2009-07-16 15:44:29 +02001033
1034}
1035
Ming Leid7aaba12009-07-16 15:44:29 +02001036static inline int __bfs_backwards(struct lock_list *src_entry,
Ming Lei9e2d5512009-07-16 15:44:29 +02001037 void *data,
1038 int (*match)(struct lock_list *entry, void *data),
1039 struct lock_list **target_entry)
Ming Leic94aa5c2009-07-16 15:44:29 +02001040{
Ming Lei9e2d5512009-07-16 15:44:29 +02001041 return __bfs(src_entry, data, match, target_entry, 0);
Ming Leic94aa5c2009-07-16 15:44:29 +02001042
1043}
1044
Peter Zijlstra8e182572007-07-19 01:48:54 -07001045/*
1046 * Recursive, forwards-direction lock-dependency checking, used for
1047 * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
1048 * checking.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001049 */
Peter Zijlstra8e182572007-07-19 01:48:54 -07001050
1051/*
1052 * Print a dependency chain entry (this is only done when a deadlock
1053 * has been detected):
1054 */
1055static noinline int
Ming Lei24208ca2009-07-16 15:44:29 +02001056print_circular_bug_entry(struct lock_list *target, int depth)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001057{
1058 if (debug_locks_silent)
1059 return 0;
1060 printk("\n-> #%u", depth);
1061 print_lock_name(target->class);
1062 printk(":\n");
1063 print_stack_trace(&target->trace, 6);
1064
1065 return 0;
1066}
1067
1068/*
1069 * When a circular dependency is detected, print the
1070 * header first:
1071 */
1072static noinline int
Ming Leidb0002a2009-07-16 15:44:29 +02001073print_circular_bug_header(struct lock_list *entry, unsigned int depth,
1074 struct held_lock *check_src,
1075 struct held_lock *check_tgt)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001076{
1077 struct task_struct *curr = current;
1078
Ming Leic94aa5c2009-07-16 15:44:29 +02001079 if (debug_locks_silent)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001080 return 0;
1081
1082 printk("\n=======================================================\n");
1083 printk( "[ INFO: possible circular locking dependency detected ]\n");
1084 print_kernel_version();
1085 printk( "-------------------------------------------------------\n");
1086 printk("%s/%d is trying to acquire lock:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001087 curr->comm, task_pid_nr(curr));
Ming Leidb0002a2009-07-16 15:44:29 +02001088 print_lock(check_src);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001089 printk("\nbut task is already holding lock:\n");
Ming Leidb0002a2009-07-16 15:44:29 +02001090 print_lock(check_tgt);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001091 printk("\nwhich lock already depends on the new lock.\n\n");
1092 printk("\nthe existing dependency chain (in reverse order) is:\n");
1093
1094 print_circular_bug_entry(entry, depth);
1095
1096 return 0;
1097}
1098
Ming Lei9e2d5512009-07-16 15:44:29 +02001099static inline int class_equal(struct lock_list *entry, void *data)
1100{
1101 return entry->class == data;
1102}
1103
Ming Leidb0002a2009-07-16 15:44:29 +02001104static noinline int print_circular_bug(struct lock_list *this,
1105 struct lock_list *target,
1106 struct held_lock *check_src,
1107 struct held_lock *check_tgt)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001108{
1109 struct task_struct *curr = current;
Ming Leic94aa5c2009-07-16 15:44:29 +02001110 struct lock_list *parent;
Ming Lei24208ca2009-07-16 15:44:29 +02001111 int depth;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001112
Ming Leic94aa5c2009-07-16 15:44:29 +02001113 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001114 return 0;
1115
Ming Leidb0002a2009-07-16 15:44:29 +02001116 if (!save_trace(&this->trace))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001117 return 0;
1118
Ming Leic94aa5c2009-07-16 15:44:29 +02001119 depth = get_lock_depth(target);
1120
Ming Leidb0002a2009-07-16 15:44:29 +02001121 print_circular_bug_header(target, depth, check_src, check_tgt);
Ming Leic94aa5c2009-07-16 15:44:29 +02001122
1123 parent = get_lock_parent(target);
1124
1125 while (parent) {
1126 print_circular_bug_entry(parent, --depth);
1127 parent = get_lock_parent(parent);
1128 }
Peter Zijlstra8e182572007-07-19 01:48:54 -07001129
1130 printk("\nother info that might help us debug this:\n\n");
1131 lockdep_print_held_locks(curr);
1132
1133 printk("\nstack backtrace:\n");
1134 dump_stack();
1135
1136 return 0;
1137}
1138
Ming Leidb0002a2009-07-16 15:44:29 +02001139static noinline int print_bfs_bug(int ret)
1140{
1141 if (!debug_locks_off_graph_unlock())
1142 return 0;
1143
1144 WARN(1, "lockdep bfs error:%d\n", ret);
1145
1146 return 0;
1147}
1148
Ming Leief681022009-07-16 15:44:29 +02001149static int noop_count(struct lock_list *entry, void *data)
David Miller419ca3f2008-07-29 21:45:03 -07001150{
Ming Leief681022009-07-16 15:44:29 +02001151 (*(unsigned long *)data)++;
1152 return 0;
David Miller419ca3f2008-07-29 21:45:03 -07001153}
1154
Ming Leief681022009-07-16 15:44:29 +02001155unsigned long __lockdep_count_forward_deps(struct lock_list *this)
1156{
1157 unsigned long count = 0;
1158 struct lock_list *uninitialized_var(target_entry);
1159
1160 __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
1161
1162 return count;
1163}
David Miller419ca3f2008-07-29 21:45:03 -07001164unsigned long lockdep_count_forward_deps(struct lock_class *class)
1165{
1166 unsigned long ret, flags;
Ming Leief681022009-07-16 15:44:29 +02001167 struct lock_list this;
1168
1169 this.parent = NULL;
1170 this.class = class;
David Miller419ca3f2008-07-29 21:45:03 -07001171
1172 local_irq_save(flags);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001173 arch_spin_lock(&lockdep_lock);
Ming Leief681022009-07-16 15:44:29 +02001174 ret = __lockdep_count_forward_deps(&this);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001175 arch_spin_unlock(&lockdep_lock);
David Miller419ca3f2008-07-29 21:45:03 -07001176 local_irq_restore(flags);
1177
1178 return ret;
1179}
1180
Ming Leief681022009-07-16 15:44:29 +02001181unsigned long __lockdep_count_backward_deps(struct lock_list *this)
David Miller419ca3f2008-07-29 21:45:03 -07001182{
Ming Leief681022009-07-16 15:44:29 +02001183 unsigned long count = 0;
1184 struct lock_list *uninitialized_var(target_entry);
David Miller419ca3f2008-07-29 21:45:03 -07001185
Ming Leief681022009-07-16 15:44:29 +02001186 __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
David Miller419ca3f2008-07-29 21:45:03 -07001187
Ming Leief681022009-07-16 15:44:29 +02001188 return count;
David Miller419ca3f2008-07-29 21:45:03 -07001189}
1190
1191unsigned long lockdep_count_backward_deps(struct lock_class *class)
1192{
1193 unsigned long ret, flags;
Ming Leief681022009-07-16 15:44:29 +02001194 struct lock_list this;
1195
1196 this.parent = NULL;
1197 this.class = class;
David Miller419ca3f2008-07-29 21:45:03 -07001198
1199 local_irq_save(flags);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001200 arch_spin_lock(&lockdep_lock);
Ming Leief681022009-07-16 15:44:29 +02001201 ret = __lockdep_count_backward_deps(&this);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001202 arch_spin_unlock(&lockdep_lock);
David Miller419ca3f2008-07-29 21:45:03 -07001203 local_irq_restore(flags);
1204
1205 return ret;
1206}
1207
Peter Zijlstra8e182572007-07-19 01:48:54 -07001208/*
1209 * Prove that the dependency graph starting at <entry> can not
1210 * lead to <target>. Print an error and return 0 if it does.
1211 */
1212static noinline int
Ming Leidb0002a2009-07-16 15:44:29 +02001213check_noncircular(struct lock_list *root, struct lock_class *target,
1214 struct lock_list **target_entry)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001215{
Ming Leidb0002a2009-07-16 15:44:29 +02001216 int result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001217
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001218 debug_atomic_inc(nr_cyclic_checks);
David Miller419ca3f2008-07-29 21:45:03 -07001219
Ming Leid7aaba12009-07-16 15:44:29 +02001220 result = __bfs_forwards(root, target, class_equal, target_entry);
Ming Leidb0002a2009-07-16 15:44:29 +02001221
1222 return result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001223}
1224
Steven Rostedt81d68a92008-05-12 21:20:42 +02001225#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001226/*
1227 * Forwards and backwards subgraph searching, for the purposes of
1228 * proving that two subgraphs can be connected by a new dependency
1229 * without creating any illegal irq-safe -> irq-unsafe lock dependency.
1230 */
Peter Zijlstra8e182572007-07-19 01:48:54 -07001231
Ming Leid7aaba12009-07-16 15:44:29 +02001232static inline int usage_match(struct lock_list *entry, void *bit)
1233{
1234 return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
1235}
1236
1237
1238
Peter Zijlstra8e182572007-07-19 01:48:54 -07001239/*
1240 * Find a node in the forwards-direction dependency sub-graph starting
Ming Leid7aaba12009-07-16 15:44:29 +02001241 * at @root->class that matches @bit.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001242 *
Ming Leid7aaba12009-07-16 15:44:29 +02001243 * Return 0 if such a node exists in the subgraph, and put that node
1244 * into *@target_entry.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001245 *
Ming Leid7aaba12009-07-16 15:44:29 +02001246 * Return 1 otherwise and keep *@target_entry unchanged.
1247 * Return <0 on error.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001248 */
Ming Leid7aaba12009-07-16 15:44:29 +02001249static int
1250find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
1251 struct lock_list **target_entry)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001252{
Ming Leid7aaba12009-07-16 15:44:29 +02001253 int result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001254
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001255 debug_atomic_inc(nr_find_usage_forwards_checks);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001256
Ming Leid7aaba12009-07-16 15:44:29 +02001257 result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
1258
1259 return result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001260}
1261
1262/*
1263 * Find a node in the backwards-direction dependency sub-graph starting
Ming Leid7aaba12009-07-16 15:44:29 +02001264 * at @root->class that matches @bit.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001265 *
Ming Leid7aaba12009-07-16 15:44:29 +02001266 * Return 0 if such a node exists in the subgraph, and put that node
1267 * into *@target_entry.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001268 *
Ming Leid7aaba12009-07-16 15:44:29 +02001269 * Return 1 otherwise and keep *@target_entry unchanged.
1270 * Return <0 on error.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001271 */
Ming Leid7aaba12009-07-16 15:44:29 +02001272static int
1273find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
1274 struct lock_list **target_entry)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001275{
Ming Leid7aaba12009-07-16 15:44:29 +02001276 int result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001277
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001278 debug_atomic_inc(nr_find_usage_backwards_checks);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001279
Ming Leid7aaba12009-07-16 15:44:29 +02001280 result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
Dave Jonesf82b2172008-08-11 09:30:23 +02001281
Ming Leid7aaba12009-07-16 15:44:29 +02001282 return result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001283}
1284
Peter Zijlstraaf012962009-07-16 15:44:29 +02001285static void print_lock_class_header(struct lock_class *class, int depth)
1286{
1287 int bit;
1288
1289 printk("%*s->", depth, "");
1290 print_lock_name(class);
1291 printk(" ops: %lu", class->ops);
1292 printk(" {\n");
1293
1294 for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
1295 if (class->usage_mask & (1 << bit)) {
1296 int len = depth;
1297
1298 len += printk("%*s %s", depth, "", usage_str[bit]);
1299 len += printk(" at:\n");
1300 print_stack_trace(class->usage_traces + bit, len);
1301 }
1302 }
1303 printk("%*s }\n", depth, "");
1304
1305 printk("%*s ... key at: ",depth,"");
1306 print_ip_sym((unsigned long)class->key);
1307}
1308
1309/*
1310 * printk the shortest lock dependencies from @start to @end in reverse order:
1311 */
1312static void __used
1313print_shortest_lock_dependencies(struct lock_list *leaf,
1314 struct lock_list *root)
1315{
1316 struct lock_list *entry = leaf;
1317 int depth;
1318
1319 /*compute depth from generated tree by BFS*/
1320 depth = get_lock_depth(leaf);
1321
1322 do {
1323 print_lock_class_header(entry->class, depth);
1324 printk("%*s ... acquired at:\n", depth, "");
1325 print_stack_trace(&entry->trace, 2);
1326 printk("\n");
1327
1328 if (depth == 0 && (entry != root)) {
1329 printk("lockdep:%s bad BFS generated tree\n", __func__);
1330 break;
1331 }
1332
1333 entry = get_lock_parent(entry);
1334 depth--;
1335 } while (entry && (depth >= 0));
1336
1337 return;
1338}
Ming Leid7aaba12009-07-16 15:44:29 +02001339
Steven Rostedt3003eba2011-04-20 21:41:54 -04001340static void
1341print_irq_lock_scenario(struct lock_list *safe_entry,
1342 struct lock_list *unsafe_entry,
1343 struct held_lock *prev,
1344 struct held_lock *next)
1345{
1346 struct lock_class *safe_class = safe_entry->class;
1347 struct lock_class *unsafe_class = unsafe_entry->class;
1348 struct lock_class *middle_class = hlock_class(prev);
1349
1350 if (middle_class == safe_class)
1351 middle_class = hlock_class(next);
1352
1353 /*
1354 * A direct locking problem where unsafe_class lock is taken
1355 * directly by safe_class lock, then all we need to show
1356 * is the deadlock scenario, as it is obvious that the
1357 * unsafe lock is taken under the safe lock.
1358 *
1359 * But if there is a chain instead, where the safe lock takes
1360 * an intermediate lock (middle_class) where this lock is
1361 * not the same as the safe lock, then the lock chain is
1362 * used to describe the problem. Otherwise we would need
1363 * to show a different CPU case for each link in the chain
1364 * from the safe_class lock to the unsafe_class lock.
1365 */
1366 if (middle_class != unsafe_class) {
1367 printk("Chain exists of:\n ");
1368 __print_lock_name(safe_class);
1369 printk(" --> ");
1370 __print_lock_name(middle_class);
1371 printk(" --> ");
1372 __print_lock_name(unsafe_class);
1373 printk("\n\n");
1374 }
1375
1376 printk(" Possible interrupt unsafe locking scenario:\n\n");
1377 printk(" CPU0 CPU1\n");
1378 printk(" ---- ----\n");
1379 printk(" lock(");
1380 __print_lock_name(unsafe_class);
1381 printk(");\n");
1382 printk(" local_irq_disable();\n");
1383 printk(" lock(");
1384 __print_lock_name(safe_class);
1385 printk(");\n");
1386 printk(" lock(");
1387 __print_lock_name(middle_class);
1388 printk(");\n");
1389 printk(" <Interrupt>\n");
1390 printk(" lock(");
1391 __print_lock_name(safe_class);
1392 printk(");\n");
1393 printk("\n *** DEADLOCK ***\n\n");
1394}
1395
Peter Zijlstra8e182572007-07-19 01:48:54 -07001396static int
1397print_bad_irq_dependency(struct task_struct *curr,
Ming Lei24208ca2009-07-16 15:44:29 +02001398 struct lock_list *prev_root,
1399 struct lock_list *next_root,
1400 struct lock_list *backwards_entry,
1401 struct lock_list *forwards_entry,
Peter Zijlstra8e182572007-07-19 01:48:54 -07001402 struct held_lock *prev,
1403 struct held_lock *next,
1404 enum lock_usage_bit bit1,
1405 enum lock_usage_bit bit2,
1406 const char *irqclass)
1407{
1408 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1409 return 0;
1410
1411 printk("\n======================================================\n");
1412 printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
1413 irqclass, irqclass);
1414 print_kernel_version();
1415 printk( "------------------------------------------------------\n");
1416 printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001417 curr->comm, task_pid_nr(curr),
Peter Zijlstra8e182572007-07-19 01:48:54 -07001418 curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
1419 curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
1420 curr->hardirqs_enabled,
1421 curr->softirqs_enabled);
1422 print_lock(next);
1423
1424 printk("\nand this task is already holding:\n");
1425 print_lock(prev);
1426 printk("which would create a new lock dependency:\n");
Dave Jonesf82b2172008-08-11 09:30:23 +02001427 print_lock_name(hlock_class(prev));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001428 printk(" ->");
Dave Jonesf82b2172008-08-11 09:30:23 +02001429 print_lock_name(hlock_class(next));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001430 printk("\n");
1431
1432 printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
1433 irqclass);
Ming Lei24208ca2009-07-16 15:44:29 +02001434 print_lock_name(backwards_entry->class);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001435 printk("\n... which became %s-irq-safe at:\n", irqclass);
1436
Ming Lei24208ca2009-07-16 15:44:29 +02001437 print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001438
1439 printk("\nto a %s-irq-unsafe lock:\n", irqclass);
Ming Lei24208ca2009-07-16 15:44:29 +02001440 print_lock_name(forwards_entry->class);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001441 printk("\n... which became %s-irq-unsafe at:\n", irqclass);
1442 printk("...");
1443
Ming Lei24208ca2009-07-16 15:44:29 +02001444 print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001445
1446 printk("\nother info that might help us debug this:\n\n");
Steven Rostedt3003eba2011-04-20 21:41:54 -04001447 print_irq_lock_scenario(backwards_entry, forwards_entry, prev, next);
1448
Peter Zijlstra8e182572007-07-19 01:48:54 -07001449 lockdep_print_held_locks(curr);
1450
Ming Lei24208ca2009-07-16 15:44:29 +02001451 printk("\nthe dependencies between %s-irq-safe lock", irqclass);
1452 printk(" and the holding lock:\n");
1453 if (!save_trace(&prev_root->trace))
1454 return 0;
1455 print_shortest_lock_dependencies(backwards_entry, prev_root);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001456
Ming Lei24208ca2009-07-16 15:44:29 +02001457 printk("\nthe dependencies between the lock to be acquired");
1458 printk(" and %s-irq-unsafe lock:\n", irqclass);
1459 if (!save_trace(&next_root->trace))
1460 return 0;
1461 print_shortest_lock_dependencies(forwards_entry, next_root);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001462
1463 printk("\nstack backtrace:\n");
1464 dump_stack();
1465
1466 return 0;
1467}
1468
1469static int
1470check_usage(struct task_struct *curr, struct held_lock *prev,
1471 struct held_lock *next, enum lock_usage_bit bit_backwards,
1472 enum lock_usage_bit bit_forwards, const char *irqclass)
1473{
1474 int ret;
Ming Lei24208ca2009-07-16 15:44:29 +02001475 struct lock_list this, that;
Ming Leid7aaba12009-07-16 15:44:29 +02001476 struct lock_list *uninitialized_var(target_entry);
Ming Lei24208ca2009-07-16 15:44:29 +02001477 struct lock_list *uninitialized_var(target_entry1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001478
Ming Leid7aaba12009-07-16 15:44:29 +02001479 this.parent = NULL;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001480
Ming Leid7aaba12009-07-16 15:44:29 +02001481 this.class = hlock_class(prev);
1482 ret = find_usage_backwards(&this, bit_backwards, &target_entry);
Peter Zijlstraaf012962009-07-16 15:44:29 +02001483 if (ret < 0)
1484 return print_bfs_bug(ret);
1485 if (ret == 1)
1486 return ret;
Ming Leid7aaba12009-07-16 15:44:29 +02001487
Ming Lei24208ca2009-07-16 15:44:29 +02001488 that.parent = NULL;
1489 that.class = hlock_class(next);
1490 ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
Peter Zijlstraaf012962009-07-16 15:44:29 +02001491 if (ret < 0)
1492 return print_bfs_bug(ret);
1493 if (ret == 1)
1494 return ret;
Ming Leid7aaba12009-07-16 15:44:29 +02001495
Ming Lei24208ca2009-07-16 15:44:29 +02001496 return print_bad_irq_dependency(curr, &this, &that,
1497 target_entry, target_entry1,
1498 prev, next,
Peter Zijlstra8e182572007-07-19 01:48:54 -07001499 bit_backwards, bit_forwards, irqclass);
1500}
1501
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001502static const char *state_names[] = {
1503#define LOCKDEP_STATE(__STATE) \
Peter Zijlstrab4b136f2009-01-29 14:50:36 +01001504 __stringify(__STATE),
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001505#include "lockdep_states.h"
1506#undef LOCKDEP_STATE
1507};
1508
1509static const char *state_rnames[] = {
1510#define LOCKDEP_STATE(__STATE) \
Peter Zijlstrab4b136f2009-01-29 14:50:36 +01001511 __stringify(__STATE)"-READ",
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001512#include "lockdep_states.h"
1513#undef LOCKDEP_STATE
1514};
1515
1516static inline const char *state_name(enum lock_usage_bit bit)
1517{
1518 return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
1519}
1520
1521static int exclusive_bit(int new_bit)
1522{
1523 /*
1524 * USED_IN
1525 * USED_IN_READ
1526 * ENABLED
1527 * ENABLED_READ
1528 *
1529 * bit 0 - write/read
1530 * bit 1 - used_in/enabled
1531 * bit 2+ state
1532 */
1533
1534 int state = new_bit & ~3;
1535 int dir = new_bit & 2;
1536
1537 /*
1538 * keep state, bit flip the direction and strip read.
1539 */
1540 return state | (dir ^ 2);
1541}
1542
1543static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
1544 struct held_lock *next, enum lock_usage_bit bit)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001545{
1546 /*
1547 * Prove that the new dependency does not connect a hardirq-safe
1548 * lock with a hardirq-unsafe lock - to achieve this we search
1549 * the backwards-subgraph starting at <prev>, and the
1550 * forwards-subgraph starting at <next>:
1551 */
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001552 if (!check_usage(curr, prev, next, bit,
1553 exclusive_bit(bit), state_name(bit)))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001554 return 0;
1555
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001556 bit++; /* _READ */
1557
Peter Zijlstra8e182572007-07-19 01:48:54 -07001558 /*
1559 * Prove that the new dependency does not connect a hardirq-safe-read
1560 * lock with a hardirq-unsafe lock - to achieve this we search
1561 * the backwards-subgraph starting at <prev>, and the
1562 * forwards-subgraph starting at <next>:
1563 */
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001564 if (!check_usage(curr, prev, next, bit,
1565 exclusive_bit(bit), state_name(bit)))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001566 return 0;
1567
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001568 return 1;
1569}
Peter Zijlstra8e182572007-07-19 01:48:54 -07001570
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001571static int
1572check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1573 struct held_lock *next)
1574{
1575#define LOCKDEP_STATE(__STATE) \
1576 if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
Nick Piggincf40bd12009-01-21 08:12:39 +01001577 return 0;
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001578#include "lockdep_states.h"
1579#undef LOCKDEP_STATE
Nick Piggincf40bd12009-01-21 08:12:39 +01001580
Peter Zijlstra8e182572007-07-19 01:48:54 -07001581 return 1;
1582}
1583
1584static void inc_chains(void)
1585{
1586 if (current->hardirq_context)
1587 nr_hardirq_chains++;
1588 else {
1589 if (current->softirq_context)
1590 nr_softirq_chains++;
1591 else
1592 nr_process_chains++;
1593 }
1594}
1595
1596#else
1597
1598static inline int
1599check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1600 struct held_lock *next)
1601{
1602 return 1;
1603}
1604
1605static inline void inc_chains(void)
1606{
1607 nr_process_chains++;
1608}
1609
1610#endif
1611
1612static int
1613print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
1614 struct held_lock *next)
1615{
1616 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1617 return 0;
1618
1619 printk("\n=============================================\n");
1620 printk( "[ INFO: possible recursive locking detected ]\n");
1621 print_kernel_version();
1622 printk( "---------------------------------------------\n");
1623 printk("%s/%d is trying to acquire lock:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001624 curr->comm, task_pid_nr(curr));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001625 print_lock(next);
1626 printk("\nbut task is already holding lock:\n");
1627 print_lock(prev);
1628
1629 printk("\nother info that might help us debug this:\n");
1630 lockdep_print_held_locks(curr);
1631
1632 printk("\nstack backtrace:\n");
1633 dump_stack();
1634
1635 return 0;
1636}
1637
1638/*
1639 * Check whether we are holding such a class already.
1640 *
1641 * (Note that this has to be done separately, because the graph cannot
1642 * detect such classes of deadlocks.)
1643 *
1644 * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
1645 */
1646static int
1647check_deadlock(struct task_struct *curr, struct held_lock *next,
1648 struct lockdep_map *next_instance, int read)
1649{
1650 struct held_lock *prev;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001651 struct held_lock *nest = NULL;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001652 int i;
1653
1654 for (i = 0; i < curr->lockdep_depth; i++) {
1655 prev = curr->held_locks + i;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001656
1657 if (prev->instance == next->nest_lock)
1658 nest = prev;
1659
Dave Jonesf82b2172008-08-11 09:30:23 +02001660 if (hlock_class(prev) != hlock_class(next))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001661 continue;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001662
Peter Zijlstra8e182572007-07-19 01:48:54 -07001663 /*
1664 * Allow read-after-read recursion of the same
1665 * lock class (i.e. read_lock(lock)+read_lock(lock)):
1666 */
1667 if ((read == 2) && prev->read)
1668 return 2;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001669
1670 /*
1671 * We're holding the nest_lock, which serializes this lock's
1672 * nesting behaviour.
1673 */
1674 if (nest)
1675 return 2;
1676
Peter Zijlstra8e182572007-07-19 01:48:54 -07001677 return print_deadlock_bug(curr, prev, next);
1678 }
1679 return 1;
1680}
1681
1682/*
1683 * There was a chain-cache miss, and we are about to add a new dependency
1684 * to a previous lock. We recursively validate the following rules:
1685 *
1686 * - would the adding of the <prev> -> <next> dependency create a
1687 * circular dependency in the graph? [== circular deadlock]
1688 *
1689 * - does the new prev->next dependency connect any hardirq-safe lock
1690 * (in the full backwards-subgraph starting at <prev>) with any
1691 * hardirq-unsafe lock (in the full forwards-subgraph starting at
1692 * <next>)? [== illegal lock inversion with hardirq contexts]
1693 *
1694 * - does the new prev->next dependency connect any softirq-safe lock
1695 * (in the full backwards-subgraph starting at <prev>) with any
1696 * softirq-unsafe lock (in the full forwards-subgraph starting at
1697 * <next>)? [== illegal lock inversion with softirq contexts]
1698 *
1699 * any of these scenarios could lead to a deadlock.
1700 *
1701 * Then if all the validations pass, we add the forwards and backwards
1702 * dependency.
1703 */
1704static int
1705check_prev_add(struct task_struct *curr, struct held_lock *prev,
Yong Zhang4726f2a2010-05-04 14:16:48 +08001706 struct held_lock *next, int distance, int trylock_loop)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001707{
1708 struct lock_list *entry;
1709 int ret;
Ming Leidb0002a2009-07-16 15:44:29 +02001710 struct lock_list this;
1711 struct lock_list *uninitialized_var(target_entry);
Yong Zhang4726f2a2010-05-04 14:16:48 +08001712 /*
1713 * Static variable, serialized by the graph_lock().
1714 *
1715 * We use this static variable to save the stack trace in case
1716 * we call into this function multiple times due to encountering
1717 * trylocks in the held lock stack.
1718 */
1719 static struct stack_trace trace;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001720
1721 /*
1722 * Prove that the new <prev> -> <next> dependency would not
1723 * create a circular dependency in the graph. (We do this by
1724 * forward-recursing into the graph starting at <next>, and
1725 * checking whether we can reach <prev>.)
1726 *
1727 * We are using global variables to control the recursion, to
1728 * keep the stackframe size of the recursive functions low:
1729 */
Ming Leidb0002a2009-07-16 15:44:29 +02001730 this.class = hlock_class(next);
1731 this.parent = NULL;
1732 ret = check_noncircular(&this, hlock_class(prev), &target_entry);
1733 if (unlikely(!ret))
1734 return print_circular_bug(&this, target_entry, next, prev);
1735 else if (unlikely(ret < 0))
1736 return print_bfs_bug(ret);
Ming Leic94aa5c2009-07-16 15:44:29 +02001737
Peter Zijlstra8e182572007-07-19 01:48:54 -07001738 if (!check_prev_add_irq(curr, prev, next))
1739 return 0;
1740
1741 /*
1742 * For recursive read-locks we do all the dependency checks,
1743 * but we dont store read-triggered dependencies (only
1744 * write-triggered dependencies). This ensures that only the
1745 * write-side dependencies matter, and that if for example a
1746 * write-lock never takes any other locks, then the reads are
1747 * equivalent to a NOP.
1748 */
1749 if (next->read == 2 || prev->read == 2)
1750 return 1;
1751 /*
1752 * Is the <prev> -> <next> dependency already present?
1753 *
1754 * (this may occur even though this is a new chain: consider
1755 * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
1756 * chains - the second one will be new, but L1 already has
1757 * L2 added to its dependency list, due to the first chain.)
1758 */
Dave Jonesf82b2172008-08-11 09:30:23 +02001759 list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
1760 if (entry->class == hlock_class(next)) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07001761 if (distance == 1)
1762 entry->distance = 1;
1763 return 2;
1764 }
1765 }
1766
Yong Zhang4726f2a2010-05-04 14:16:48 +08001767 if (!trylock_loop && !save_trace(&trace))
1768 return 0;
1769
Peter Zijlstra8e182572007-07-19 01:48:54 -07001770 /*
1771 * Ok, all validations passed, add the new lock
1772 * to the previous lock's dependency list:
1773 */
Dave Jonesf82b2172008-08-11 09:30:23 +02001774 ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
1775 &hlock_class(prev)->locks_after,
Yong Zhang4726f2a2010-05-04 14:16:48 +08001776 next->acquire_ip, distance, &trace);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001777
1778 if (!ret)
1779 return 0;
1780
Dave Jonesf82b2172008-08-11 09:30:23 +02001781 ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
1782 &hlock_class(next)->locks_before,
Yong Zhang4726f2a2010-05-04 14:16:48 +08001783 next->acquire_ip, distance, &trace);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001784 if (!ret)
1785 return 0;
1786
1787 /*
1788 * Debugging printouts:
1789 */
Dave Jonesf82b2172008-08-11 09:30:23 +02001790 if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07001791 graph_unlock();
1792 printk("\n new dependency: ");
Dave Jonesf82b2172008-08-11 09:30:23 +02001793 print_lock_name(hlock_class(prev));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001794 printk(" => ");
Dave Jonesf82b2172008-08-11 09:30:23 +02001795 print_lock_name(hlock_class(next));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001796 printk("\n");
1797 dump_stack();
1798 return graph_lock();
1799 }
1800 return 1;
1801}
1802
1803/*
1804 * Add the dependency to all directly-previous locks that are 'relevant'.
1805 * The ones that are relevant are (in increasing distance from curr):
1806 * all consecutive trylock entries and the final non-trylock entry - or
1807 * the end of this context's lock-chain - whichever comes first.
1808 */
1809static int
1810check_prevs_add(struct task_struct *curr, struct held_lock *next)
1811{
1812 int depth = curr->lockdep_depth;
Yong Zhang4726f2a2010-05-04 14:16:48 +08001813 int trylock_loop = 0;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001814 struct held_lock *hlock;
1815
1816 /*
1817 * Debugging checks.
1818 *
1819 * Depth must not be zero for a non-head lock:
1820 */
1821 if (!depth)
1822 goto out_bug;
1823 /*
1824 * At least two relevant locks must exist for this
1825 * to be a head:
1826 */
1827 if (curr->held_locks[depth].irq_context !=
1828 curr->held_locks[depth-1].irq_context)
1829 goto out_bug;
1830
1831 for (;;) {
1832 int distance = curr->lockdep_depth - depth + 1;
1833 hlock = curr->held_locks + depth-1;
1834 /*
1835 * Only non-recursive-read entries get new dependencies
1836 * added:
1837 */
1838 if (hlock->read != 2) {
Yong Zhang4726f2a2010-05-04 14:16:48 +08001839 if (!check_prev_add(curr, hlock, next,
1840 distance, trylock_loop))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001841 return 0;
1842 /*
1843 * Stop after the first non-trylock entry,
1844 * as non-trylock entries have added their
1845 * own direct dependencies already, so this
1846 * lock is connected to them indirectly:
1847 */
1848 if (!hlock->trylock)
1849 break;
1850 }
1851 depth--;
1852 /*
1853 * End of lock-stack?
1854 */
1855 if (!depth)
1856 break;
1857 /*
1858 * Stop the search if we cross into another context:
1859 */
1860 if (curr->held_locks[depth].irq_context !=
1861 curr->held_locks[depth-1].irq_context)
1862 break;
Yong Zhang4726f2a2010-05-04 14:16:48 +08001863 trylock_loop = 1;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001864 }
1865 return 1;
1866out_bug:
1867 if (!debug_locks_off_graph_unlock())
1868 return 0;
1869
1870 WARN_ON(1);
1871
1872 return 0;
1873}
1874
1875unsigned long nr_lock_chains;
Huang, Ying443cd502008-06-20 16:39:21 +08001876struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
Huang, Yingcd1a28e2008-06-23 11:20:54 +08001877int nr_chain_hlocks;
Huang, Ying443cd502008-06-20 16:39:21 +08001878static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
1879
1880struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
1881{
1882 return lock_classes + chain_hlocks[chain->base + i];
1883}
Peter Zijlstra8e182572007-07-19 01:48:54 -07001884
1885/*
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001886 * Look up a dependency chain. If the key is not present yet then
Jarek Poplawski9e860d02007-05-08 00:30:12 -07001887 * add it and return 1 - in this case the new dependency chain is
1888 * validated. If the key is already hashed, return 0.
1889 * (On return with 1 graph_lock is held.)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001890 */
Huang, Ying443cd502008-06-20 16:39:21 +08001891static inline int lookup_chain_cache(struct task_struct *curr,
1892 struct held_lock *hlock,
1893 u64 chain_key)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001894{
Dave Jonesf82b2172008-08-11 09:30:23 +02001895 struct lock_class *class = hlock_class(hlock);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001896 struct list_head *hash_head = chainhashentry(chain_key);
1897 struct lock_chain *chain;
Huang, Ying443cd502008-06-20 16:39:21 +08001898 struct held_lock *hlock_curr, *hlock_next;
Huang, Yingcd1a28e2008-06-23 11:20:54 +08001899 int i, j, n, cn;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001900
Jarek Poplawski381a2292007-02-10 01:44:58 -08001901 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
1902 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001903 /*
1904 * We can walk it lock-free, because entries only get added
1905 * to the hash:
1906 */
1907 list_for_each_entry(chain, hash_head, entry) {
1908 if (chain->chain_key == chain_key) {
1909cache_hit:
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001910 debug_atomic_inc(chain_lookup_hits);
Ingo Molnar81fc6852006-12-13 00:34:40 -08001911 if (very_verbose(class))
Andrew Morton755cd902006-12-29 16:49:14 -08001912 printk("\nhash chain already cached, key: "
1913 "%016Lx tail class: [%p] %s\n",
1914 (unsigned long long)chain_key,
1915 class->key, class->name);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001916 return 0;
1917 }
1918 }
Ingo Molnar81fc6852006-12-13 00:34:40 -08001919 if (very_verbose(class))
Andrew Morton755cd902006-12-29 16:49:14 -08001920 printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
1921 (unsigned long long)chain_key, class->key, class->name);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001922 /*
1923 * Allocate a new chain entry from the static array, and add
1924 * it to the hash:
1925 */
Ingo Molnar74c383f2006-12-13 00:34:43 -08001926 if (!graph_lock())
1927 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001928 /*
1929 * We have to walk the chain again locked - to avoid duplicates:
1930 */
1931 list_for_each_entry(chain, hash_head, entry) {
1932 if (chain->chain_key == chain_key) {
Ingo Molnar74c383f2006-12-13 00:34:43 -08001933 graph_unlock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001934 goto cache_hit;
1935 }
1936 }
1937 if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
Ingo Molnar74c383f2006-12-13 00:34:43 -08001938 if (!debug_locks_off_graph_unlock())
1939 return 0;
1940
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001941 printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
1942 printk("turning off the locking correctness validator.\n");
Peter Zijlstraeedeeab2009-03-18 12:38:47 +01001943 dump_stack();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001944 return 0;
1945 }
1946 chain = lock_chains + nr_lock_chains++;
1947 chain->chain_key = chain_key;
Huang, Ying443cd502008-06-20 16:39:21 +08001948 chain->irq_context = hlock->irq_context;
1949 /* Find the first held_lock of current chain */
1950 hlock_next = hlock;
1951 for (i = curr->lockdep_depth - 1; i >= 0; i--) {
1952 hlock_curr = curr->held_locks + i;
1953 if (hlock_curr->irq_context != hlock_next->irq_context)
1954 break;
1955 hlock_next = hlock;
1956 }
1957 i++;
1958 chain->depth = curr->lockdep_depth + 1 - i;
Huang, Yingcd1a28e2008-06-23 11:20:54 +08001959 cn = nr_chain_hlocks;
1960 while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) {
1961 n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth);
1962 if (n == cn)
1963 break;
1964 cn = n;
1965 }
1966 if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
1967 chain->base = cn;
Huang, Ying443cd502008-06-20 16:39:21 +08001968 for (j = 0; j < chain->depth - 1; j++, i++) {
Dave Jonesf82b2172008-08-11 09:30:23 +02001969 int lock_id = curr->held_locks[i].class_idx - 1;
Huang, Ying443cd502008-06-20 16:39:21 +08001970 chain_hlocks[chain->base + j] = lock_id;
1971 }
1972 chain_hlocks[chain->base + j] = class - lock_classes;
1973 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001974 list_add_tail_rcu(&chain->entry, hash_head);
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001975 debug_atomic_inc(chain_lookup_misses);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001976 inc_chains();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001977
1978 return 1;
1979}
Peter Zijlstra8e182572007-07-19 01:48:54 -07001980
1981static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
Johannes Berg4e6045f2007-10-18 23:39:55 -07001982 struct held_lock *hlock, int chain_head, u64 chain_key)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001983{
1984 /*
1985 * Trylock needs to maintain the stack of held locks, but it
1986 * does not add new dependencies, because trylock can be done
1987 * in any order.
1988 *
1989 * We look up the chain_key and do the O(N^2) check and update of
1990 * the dependencies only if this is a new dependency chain.
1991 * (If lookup_chain_cache() returns with 1 it acquires
1992 * graph_lock for us)
1993 */
1994 if (!hlock->trylock && (hlock->check == 2) &&
Huang, Ying443cd502008-06-20 16:39:21 +08001995 lookup_chain_cache(curr, hlock, chain_key)) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07001996 /*
1997 * Check whether last held lock:
1998 *
1999 * - is irq-safe, if this lock is irq-unsafe
2000 * - is softirq-safe, if this lock is hardirq-unsafe
2001 *
2002 * And check whether the new lock's dependency graph
2003 * could lead back to the previous lock.
2004 *
2005 * any of these scenarios could lead to a deadlock. If
2006 * All validations
2007 */
2008 int ret = check_deadlock(curr, hlock, lock, hlock->read);
2009
2010 if (!ret)
2011 return 0;
2012 /*
2013 * Mark recursive read, as we jump over it when
2014 * building dependencies (just like we jump over
2015 * trylock entries):
2016 */
2017 if (ret == 2)
2018 hlock->read = 2;
2019 /*
2020 * Add dependency only if this lock is not the head
2021 * of the chain, and if it's not a secondary read-lock:
2022 */
2023 if (!chain_head && ret != 2)
2024 if (!check_prevs_add(curr, hlock))
2025 return 0;
2026 graph_unlock();
2027 } else
2028 /* after lookup_chain_cache(): */
2029 if (unlikely(!debug_locks))
2030 return 0;
2031
2032 return 1;
2033}
2034#else
2035static inline int validate_chain(struct task_struct *curr,
2036 struct lockdep_map *lock, struct held_lock *hlock,
Gregory Haskins3aa416b2007-10-11 22:11:11 +02002037 int chain_head, u64 chain_key)
Peter Zijlstra8e182572007-07-19 01:48:54 -07002038{
2039 return 1;
2040}
Peter Zijlstraca58abc2007-07-19 01:48:53 -07002041#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002042
2043/*
2044 * We are building curr_chain_key incrementally, so double-check
2045 * it from scratch, to make sure that it's done correctly:
2046 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002047static void check_chain_key(struct task_struct *curr)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002048{
2049#ifdef CONFIG_DEBUG_LOCKDEP
2050 struct held_lock *hlock, *prev_hlock = NULL;
2051 unsigned int i, id;
2052 u64 chain_key = 0;
2053
2054 for (i = 0; i < curr->lockdep_depth; i++) {
2055 hlock = curr->held_locks + i;
2056 if (chain_key != hlock->prev_chain_key) {
2057 debug_locks_off();
Arjan van de Ven2df8b1d2008-07-30 12:43:11 -07002058 WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002059 curr->lockdep_depth, i,
2060 (unsigned long long)chain_key,
2061 (unsigned long long)hlock->prev_chain_key);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002062 return;
2063 }
Dave Jonesf82b2172008-08-11 09:30:23 +02002064 id = hlock->class_idx - 1;
Jarek Poplawski381a2292007-02-10 01:44:58 -08002065 if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
2066 return;
2067
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002068 if (prev_hlock && (prev_hlock->irq_context !=
2069 hlock->irq_context))
2070 chain_key = 0;
2071 chain_key = iterate_chain_key(chain_key, id);
2072 prev_hlock = hlock;
2073 }
2074 if (chain_key != curr->curr_chain_key) {
2075 debug_locks_off();
Arjan van de Ven2df8b1d2008-07-30 12:43:11 -07002076 WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002077 curr->lockdep_depth, i,
2078 (unsigned long long)chain_key,
2079 (unsigned long long)curr->curr_chain_key);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002080 }
2081#endif
2082}
2083
Peter Zijlstra8e182572007-07-19 01:48:54 -07002084static int
2085print_usage_bug(struct task_struct *curr, struct held_lock *this,
2086 enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
2087{
2088 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2089 return 0;
2090
2091 printk("\n=================================\n");
2092 printk( "[ INFO: inconsistent lock state ]\n");
2093 print_kernel_version();
2094 printk( "---------------------------------\n");
2095
2096 printk("inconsistent {%s} -> {%s} usage.\n",
2097 usage_str[prev_bit], usage_str[new_bit]);
2098
2099 printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07002100 curr->comm, task_pid_nr(curr),
Peter Zijlstra8e182572007-07-19 01:48:54 -07002101 trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
2102 trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
2103 trace_hardirqs_enabled(curr),
2104 trace_softirqs_enabled(curr));
2105 print_lock(this);
2106
2107 printk("{%s} state was registered at:\n", usage_str[prev_bit]);
Dave Jonesf82b2172008-08-11 09:30:23 +02002108 print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07002109
2110 print_irqtrace_events(curr);
2111 printk("\nother info that might help us debug this:\n");
2112 lockdep_print_held_locks(curr);
2113
2114 printk("\nstack backtrace:\n");
2115 dump_stack();
2116
2117 return 0;
2118}
2119
2120/*
2121 * Print out an error if an invalid bit is set:
2122 */
2123static inline int
2124valid_state(struct task_struct *curr, struct held_lock *this,
2125 enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
2126{
Dave Jonesf82b2172008-08-11 09:30:23 +02002127 if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002128 return print_usage_bug(curr, this, bad_bit, new_bit);
2129 return 1;
2130}
2131
2132static int mark_lock(struct task_struct *curr, struct held_lock *this,
2133 enum lock_usage_bit new_bit);
2134
Steven Rostedt81d68a92008-05-12 21:20:42 +02002135#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002136
2137/*
2138 * print irq inversion bug:
2139 */
2140static int
Ming Lei24208ca2009-07-16 15:44:29 +02002141print_irq_inversion_bug(struct task_struct *curr,
2142 struct lock_list *root, struct lock_list *other,
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002143 struct held_lock *this, int forwards,
2144 const char *irqclass)
2145{
Ingo Molnar74c383f2006-12-13 00:34:43 -08002146 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002147 return 0;
2148
2149 printk("\n=========================================================\n");
2150 printk( "[ INFO: possible irq lock inversion dependency detected ]\n");
Dave Jones99de0552006-09-29 02:00:10 -07002151 print_kernel_version();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002152 printk( "---------------------------------------------------------\n");
2153 printk("%s/%d just changed the state of lock:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07002154 curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002155 print_lock(this);
2156 if (forwards)
Peter Zijlstra26575e22009-03-04 14:53:24 +01002157 printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002158 else
Peter Zijlstra26575e22009-03-04 14:53:24 +01002159 printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
Ming Lei24208ca2009-07-16 15:44:29 +02002160 print_lock_name(other->class);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002161 printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
2162
2163 printk("\nother info that might help us debug this:\n");
2164 lockdep_print_held_locks(curr);
2165
Ming Lei24208ca2009-07-16 15:44:29 +02002166 printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
2167 if (!save_trace(&root->trace))
2168 return 0;
2169 print_shortest_lock_dependencies(other, root);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002170
2171 printk("\nstack backtrace:\n");
2172 dump_stack();
2173
2174 return 0;
2175}
2176
2177/*
2178 * Prove that in the forwards-direction subgraph starting at <this>
2179 * there is no lock matching <mask>:
2180 */
2181static int
2182check_usage_forwards(struct task_struct *curr, struct held_lock *this,
2183 enum lock_usage_bit bit, const char *irqclass)
2184{
2185 int ret;
Ming Leid7aaba12009-07-16 15:44:29 +02002186 struct lock_list root;
2187 struct lock_list *uninitialized_var(target_entry);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002188
Ming Leid7aaba12009-07-16 15:44:29 +02002189 root.parent = NULL;
2190 root.class = hlock_class(this);
2191 ret = find_usage_forwards(&root, bit, &target_entry);
Peter Zijlstraaf012962009-07-16 15:44:29 +02002192 if (ret < 0)
2193 return print_bfs_bug(ret);
2194 if (ret == 1)
2195 return ret;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002196
Ming Lei24208ca2009-07-16 15:44:29 +02002197 return print_irq_inversion_bug(curr, &root, target_entry,
Ming Leid7aaba12009-07-16 15:44:29 +02002198 this, 1, irqclass);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002199}
2200
2201/*
2202 * Prove that in the backwards-direction subgraph starting at <this>
2203 * there is no lock matching <mask>:
2204 */
2205static int
2206check_usage_backwards(struct task_struct *curr, struct held_lock *this,
2207 enum lock_usage_bit bit, const char *irqclass)
2208{
2209 int ret;
Ming Leid7aaba12009-07-16 15:44:29 +02002210 struct lock_list root;
2211 struct lock_list *uninitialized_var(target_entry);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002212
Ming Leid7aaba12009-07-16 15:44:29 +02002213 root.parent = NULL;
2214 root.class = hlock_class(this);
2215 ret = find_usage_backwards(&root, bit, &target_entry);
Peter Zijlstraaf012962009-07-16 15:44:29 +02002216 if (ret < 0)
2217 return print_bfs_bug(ret);
2218 if (ret == 1)
2219 return ret;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002220
Ming Lei24208ca2009-07-16 15:44:29 +02002221 return print_irq_inversion_bug(curr, &root, target_entry,
Oleg Nesterov48d50672010-01-26 19:16:41 +01002222 this, 0, irqclass);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002223}
2224
Ingo Molnar3117df02006-12-13 00:34:43 -08002225void print_irqtrace_events(struct task_struct *curr)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002226{
2227 printk("irq event stamp: %u\n", curr->irq_events);
2228 printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
2229 print_ip_sym(curr->hardirq_enable_ip);
2230 printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
2231 print_ip_sym(curr->hardirq_disable_ip);
2232 printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
2233 print_ip_sym(curr->softirq_enable_ip);
2234 printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
2235 print_ip_sym(curr->softirq_disable_ip);
2236}
2237
Peter Zijlstracd953022009-01-22 16:38:21 +01002238static int HARDIRQ_verbose(struct lock_class *class)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002239{
Peter Zijlstra8e182572007-07-19 01:48:54 -07002240#if HARDIRQ_VERBOSE
2241 return class_filter(class);
2242#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002243 return 0;
2244}
2245
Peter Zijlstracd953022009-01-22 16:38:21 +01002246static int SOFTIRQ_verbose(struct lock_class *class)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002247{
Peter Zijlstra8e182572007-07-19 01:48:54 -07002248#if SOFTIRQ_VERBOSE
2249 return class_filter(class);
2250#endif
2251 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002252}
2253
Peter Zijlstracd953022009-01-22 16:38:21 +01002254static int RECLAIM_FS_verbose(struct lock_class *class)
Nick Piggincf40bd12009-01-21 08:12:39 +01002255{
2256#if RECLAIM_VERBOSE
2257 return class_filter(class);
2258#endif
2259 return 0;
2260}
2261
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002262#define STRICT_READ_CHECKS 1
2263
Peter Zijlstracd953022009-01-22 16:38:21 +01002264static int (*state_verbose_f[])(struct lock_class *class) = {
2265#define LOCKDEP_STATE(__STATE) \
2266 __STATE##_verbose,
2267#include "lockdep_states.h"
2268#undef LOCKDEP_STATE
2269};
2270
2271static inline int state_verbose(enum lock_usage_bit bit,
2272 struct lock_class *class)
2273{
2274 return state_verbose_f[bit >> 2](class);
2275}
2276
Peter Zijlstra42c50d52009-01-22 16:58:16 +01002277typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
2278 enum lock_usage_bit bit, const char *name);
2279
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002280static int
Peter Zijlstra1c21f142009-03-04 13:51:13 +01002281mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2282 enum lock_usage_bit new_bit)
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002283{
Peter Zijlstraf9892092009-01-22 16:09:59 +01002284 int excl_bit = exclusive_bit(new_bit);
Peter Zijlstra9d3651a2009-01-22 17:18:32 +01002285 int read = new_bit & 1;
Peter Zijlstra42c50d52009-01-22 16:58:16 +01002286 int dir = new_bit & 2;
2287
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002288 /*
2289 * mark USED_IN has to look forwards -- to ensure no dependency
2290 * has ENABLED state, which would allow recursion deadlocks.
2291 *
2292 * mark ENABLED has to look backwards -- to ensure no dependee
2293 * has USED_IN state, which, again, would allow recursion deadlocks.
2294 */
Peter Zijlstra42c50d52009-01-22 16:58:16 +01002295 check_usage_f usage = dir ?
2296 check_usage_backwards : check_usage_forwards;
Peter Zijlstraf9892092009-01-22 16:09:59 +01002297
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002298 /*
2299 * Validate that this particular lock does not have conflicting
2300 * usage states.
2301 */
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002302 if (!valid_state(curr, this, new_bit, excl_bit))
2303 return 0;
Peter Zijlstra9d3651a2009-01-22 17:18:32 +01002304
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002305 /*
2306 * Validate that the lock dependencies don't have conflicting usage
2307 * states.
2308 */
2309 if ((!read || !dir || STRICT_READ_CHECKS) &&
Peter Zijlstra1c21f142009-03-04 13:51:13 +01002310 !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002311 return 0;
Peter Zijlstra780e8202009-01-22 16:51:29 +01002312
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002313 /*
2314 * Check for read in write conflicts
2315 */
2316 if (!read) {
2317 if (!valid_state(curr, this, new_bit, excl_bit + 1))
2318 return 0;
2319
2320 if (STRICT_READ_CHECKS &&
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01002321 !usage(curr, this, excl_bit + 1,
2322 state_name(new_bit + 1)))
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002323 return 0;
2324 }
Peter Zijlstra780e8202009-01-22 16:51:29 +01002325
Peter Zijlstracd953022009-01-22 16:38:21 +01002326 if (state_verbose(new_bit, hlock_class(this)))
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002327 return 2;
2328
2329 return 1;
2330}
2331
Nick Piggincf40bd12009-01-21 08:12:39 +01002332enum mark_type {
Peter Zijlstra36bfb9b2009-01-22 14:12:41 +01002333#define LOCKDEP_STATE(__STATE) __STATE,
2334#include "lockdep_states.h"
2335#undef LOCKDEP_STATE
Nick Piggincf40bd12009-01-21 08:12:39 +01002336};
2337
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002338/*
2339 * Mark all held locks with a usage bit:
2340 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002341static int
Nick Piggincf40bd12009-01-21 08:12:39 +01002342mark_held_locks(struct task_struct *curr, enum mark_type mark)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002343{
2344 enum lock_usage_bit usage_bit;
2345 struct held_lock *hlock;
2346 int i;
2347
2348 for (i = 0; i < curr->lockdep_depth; i++) {
2349 hlock = curr->held_locks + i;
2350
Peter Zijlstracf2ad4d2009-01-27 13:58:08 +01002351 usage_bit = 2 + (mark << 2); /* ENABLED */
2352 if (hlock->read)
2353 usage_bit += 1; /* READ */
2354
2355 BUG_ON(usage_bit >= LOCK_USAGE_STATES);
Nick Piggincf40bd12009-01-21 08:12:39 +01002356
Jarek Poplawski4ff773bb2007-05-08 00:31:00 -07002357 if (!mark_lock(curr, hlock, usage_bit))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002358 return 0;
2359 }
2360
2361 return 1;
2362}
2363
2364/*
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002365 * Hardirqs will be enabled:
2366 */
Heiko Carstens6afe40b2008-10-28 11:14:58 +01002367void trace_hardirqs_on_caller(unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002368{
2369 struct task_struct *curr = current;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002370
Heiko Carstens6afe40b2008-10-28 11:14:58 +01002371 time_hardirqs_on(CALLER_ADDR0, ip);
Steven Rostedt81d68a92008-05-12 21:20:42 +02002372
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002373 if (unlikely(!debug_locks || current->lockdep_recursion))
2374 return;
2375
Tejun Heo2ce802f2011-01-20 12:06:35 +01002376 if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002377 return;
2378
2379 if (unlikely(curr->hardirqs_enabled)) {
Frederic Weisbecker8795d772010-04-15 23:10:42 +02002380 /*
2381 * Neither irq nor preemption are disabled here
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002382 * so this is racy by nature but losing one hit
Frederic Weisbecker8795d772010-04-15 23:10:42 +02002383 * in a stat is not a big deal.
2384 */
Frederic Weisbeckerba697f42010-05-04 04:47:25 +02002385 __debug_atomic_inc(redundant_hardirqs_on);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002386 return;
2387 }
2388 /* we'll do an OFF -> ON transition: */
2389 curr->hardirqs_enabled = 1;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002390
2391 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2392 return;
2393 if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
2394 return;
2395 /*
2396 * We are going to turn hardirqs on, so set the
2397 * usage bit for all held locks:
2398 */
Nick Piggincf40bd12009-01-21 08:12:39 +01002399 if (!mark_held_locks(curr, HARDIRQ))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002400 return;
2401 /*
2402 * If we have softirqs enabled, then set the usage
2403 * bit for all held locks. (disabled hardirqs prevented
2404 * this bit from being set before)
2405 */
2406 if (curr->softirqs_enabled)
Nick Piggincf40bd12009-01-21 08:12:39 +01002407 if (!mark_held_locks(curr, SOFTIRQ))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002408 return;
2409
2410 curr->hardirq_enable_ip = ip;
2411 curr->hardirq_enable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002412 debug_atomic_inc(hardirqs_on_events);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002413}
Steven Rostedt81d68a92008-05-12 21:20:42 +02002414EXPORT_SYMBOL(trace_hardirqs_on_caller);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002415
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002416void trace_hardirqs_on(void)
Steven Rostedt81d68a92008-05-12 21:20:42 +02002417{
2418 trace_hardirqs_on_caller(CALLER_ADDR0);
2419}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002420EXPORT_SYMBOL(trace_hardirqs_on);
2421
2422/*
2423 * Hardirqs were disabled:
2424 */
Heiko Carstens6afe40b2008-10-28 11:14:58 +01002425void trace_hardirqs_off_caller(unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002426{
2427 struct task_struct *curr = current;
2428
Heiko Carstens6afe40b2008-10-28 11:14:58 +01002429 time_hardirqs_off(CALLER_ADDR0, ip);
Steven Rostedt81d68a92008-05-12 21:20:42 +02002430
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002431 if (unlikely(!debug_locks || current->lockdep_recursion))
2432 return;
2433
2434 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2435 return;
2436
2437 if (curr->hardirqs_enabled) {
2438 /*
2439 * We have done an ON -> OFF transition:
2440 */
2441 curr->hardirqs_enabled = 0;
Heiko Carstens6afe40b2008-10-28 11:14:58 +01002442 curr->hardirq_disable_ip = ip;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002443 curr->hardirq_disable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002444 debug_atomic_inc(hardirqs_off_events);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002445 } else
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002446 debug_atomic_inc(redundant_hardirqs_off);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002447}
Steven Rostedt81d68a92008-05-12 21:20:42 +02002448EXPORT_SYMBOL(trace_hardirqs_off_caller);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002449
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002450void trace_hardirqs_off(void)
Steven Rostedt81d68a92008-05-12 21:20:42 +02002451{
2452 trace_hardirqs_off_caller(CALLER_ADDR0);
2453}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002454EXPORT_SYMBOL(trace_hardirqs_off);
2455
2456/*
2457 * Softirqs will be enabled:
2458 */
2459void trace_softirqs_on(unsigned long ip)
2460{
2461 struct task_struct *curr = current;
2462
2463 if (unlikely(!debug_locks))
2464 return;
2465
2466 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2467 return;
2468
2469 if (curr->softirqs_enabled) {
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002470 debug_atomic_inc(redundant_softirqs_on);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002471 return;
2472 }
2473
2474 /*
2475 * We'll do an OFF -> ON transition:
2476 */
2477 curr->softirqs_enabled = 1;
2478 curr->softirq_enable_ip = ip;
2479 curr->softirq_enable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002480 debug_atomic_inc(softirqs_on_events);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002481 /*
2482 * We are going to turn softirqs on, so set the
2483 * usage bit for all held locks, if hardirqs are
2484 * enabled too:
2485 */
2486 if (curr->hardirqs_enabled)
Nick Piggincf40bd12009-01-21 08:12:39 +01002487 mark_held_locks(curr, SOFTIRQ);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002488}
2489
2490/*
2491 * Softirqs were disabled:
2492 */
2493void trace_softirqs_off(unsigned long ip)
2494{
2495 struct task_struct *curr = current;
2496
2497 if (unlikely(!debug_locks))
2498 return;
2499
2500 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2501 return;
2502
2503 if (curr->softirqs_enabled) {
2504 /*
2505 * We have done an ON -> OFF transition:
2506 */
2507 curr->softirqs_enabled = 0;
2508 curr->softirq_disable_ip = ip;
2509 curr->softirq_disable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002510 debug_atomic_inc(softirqs_off_events);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002511 DEBUG_LOCKS_WARN_ON(!softirq_count());
2512 } else
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002513 debug_atomic_inc(redundant_softirqs_off);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002514}
2515
Peter Zijlstra2f850182009-03-20 11:13:20 +01002516static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
Nick Piggincf40bd12009-01-21 08:12:39 +01002517{
2518 struct task_struct *curr = current;
2519
2520 if (unlikely(!debug_locks))
2521 return;
2522
2523 /* no reclaim without waiting on it */
2524 if (!(gfp_mask & __GFP_WAIT))
2525 return;
2526
2527 /* this guy won't enter reclaim */
2528 if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
2529 return;
2530
2531 /* We're only interested __GFP_FS allocations for now */
2532 if (!(gfp_mask & __GFP_FS))
2533 return;
2534
Peter Zijlstra2f850182009-03-20 11:13:20 +01002535 if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
Nick Piggincf40bd12009-01-21 08:12:39 +01002536 return;
2537
2538 mark_held_locks(curr, RECLAIM_FS);
2539}
2540
Peter Zijlstra2f850182009-03-20 11:13:20 +01002541static void check_flags(unsigned long flags);
2542
2543void lockdep_trace_alloc(gfp_t gfp_mask)
2544{
2545 unsigned long flags;
2546
2547 if (unlikely(current->lockdep_recursion))
2548 return;
2549
2550 raw_local_irq_save(flags);
2551 check_flags(flags);
2552 current->lockdep_recursion = 1;
2553 __lockdep_trace_alloc(gfp_mask, flags);
2554 current->lockdep_recursion = 0;
2555 raw_local_irq_restore(flags);
2556}
2557
Peter Zijlstra8e182572007-07-19 01:48:54 -07002558static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
2559{
2560 /*
2561 * If non-trylock use in a hardirq or softirq context, then
2562 * mark the lock as used in these contexts:
2563 */
2564 if (!hlock->trylock) {
2565 if (hlock->read) {
2566 if (curr->hardirq_context)
2567 if (!mark_lock(curr, hlock,
2568 LOCK_USED_IN_HARDIRQ_READ))
2569 return 0;
2570 if (curr->softirq_context)
2571 if (!mark_lock(curr, hlock,
2572 LOCK_USED_IN_SOFTIRQ_READ))
2573 return 0;
2574 } else {
2575 if (curr->hardirq_context)
2576 if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
2577 return 0;
2578 if (curr->softirq_context)
2579 if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
2580 return 0;
2581 }
2582 }
2583 if (!hlock->hardirqs_off) {
2584 if (hlock->read) {
2585 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002586 LOCK_ENABLED_HARDIRQ_READ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002587 return 0;
2588 if (curr->softirqs_enabled)
2589 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002590 LOCK_ENABLED_SOFTIRQ_READ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002591 return 0;
2592 } else {
2593 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002594 LOCK_ENABLED_HARDIRQ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002595 return 0;
2596 if (curr->softirqs_enabled)
2597 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002598 LOCK_ENABLED_SOFTIRQ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002599 return 0;
2600 }
2601 }
2602
Nick Piggincf40bd12009-01-21 08:12:39 +01002603 /*
2604 * We reuse the irq context infrastructure more broadly as a general
2605 * context checking code. This tests GFP_FS recursion (a lock taken
2606 * during reclaim for a GFP_FS allocation is held over a GFP_FS
2607 * allocation).
2608 */
2609 if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
2610 if (hlock->read) {
2611 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
2612 return 0;
2613 } else {
2614 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
2615 return 0;
2616 }
2617 }
2618
Peter Zijlstra8e182572007-07-19 01:48:54 -07002619 return 1;
2620}
2621
2622static int separate_irq_context(struct task_struct *curr,
2623 struct held_lock *hlock)
2624{
2625 unsigned int depth = curr->lockdep_depth;
2626
2627 /*
2628 * Keep track of points where we cross into an interrupt context:
2629 */
2630 hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
2631 curr->softirq_context;
2632 if (depth) {
2633 struct held_lock *prev_hlock;
2634
2635 prev_hlock = curr->held_locks + depth-1;
2636 /*
2637 * If we cross into another context, reset the
2638 * hash key (this also prevents the checking and the
2639 * adding of the dependency to 'prev'):
2640 */
2641 if (prev_hlock->irq_context != hlock->irq_context)
2642 return 1;
2643 }
2644 return 0;
2645}
2646
2647#else
2648
2649static inline
2650int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2651 enum lock_usage_bit new_bit)
2652{
2653 WARN_ON(1);
2654 return 1;
2655}
2656
2657static inline int mark_irqflags(struct task_struct *curr,
2658 struct held_lock *hlock)
2659{
2660 return 1;
2661}
2662
2663static inline int separate_irq_context(struct task_struct *curr,
2664 struct held_lock *hlock)
2665{
2666 return 0;
2667}
2668
Peter Zijlstra868a23a2009-02-15 00:25:21 +01002669void lockdep_trace_alloc(gfp_t gfp_mask)
2670{
2671}
2672
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002673#endif
2674
2675/*
Peter Zijlstra8e182572007-07-19 01:48:54 -07002676 * Mark a lock with a usage bit, and validate the state transition:
2677 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002678static int mark_lock(struct task_struct *curr, struct held_lock *this,
Steven Rostedt0764d232008-05-12 21:20:44 +02002679 enum lock_usage_bit new_bit)
Peter Zijlstra8e182572007-07-19 01:48:54 -07002680{
2681 unsigned int new_mask = 1 << new_bit, ret = 1;
2682
2683 /*
2684 * If already set then do not dirty the cacheline,
2685 * nor do any checks:
2686 */
Dave Jonesf82b2172008-08-11 09:30:23 +02002687 if (likely(hlock_class(this)->usage_mask & new_mask))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002688 return 1;
2689
2690 if (!graph_lock())
2691 return 0;
2692 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002693 * Make sure we didn't race:
Peter Zijlstra8e182572007-07-19 01:48:54 -07002694 */
Dave Jonesf82b2172008-08-11 09:30:23 +02002695 if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07002696 graph_unlock();
2697 return 1;
2698 }
2699
Dave Jonesf82b2172008-08-11 09:30:23 +02002700 hlock_class(this)->usage_mask |= new_mask;
Peter Zijlstra8e182572007-07-19 01:48:54 -07002701
Dave Jonesf82b2172008-08-11 09:30:23 +02002702 if (!save_trace(hlock_class(this)->usage_traces + new_bit))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002703 return 0;
2704
2705 switch (new_bit) {
Peter Zijlstra53464172009-01-22 14:15:53 +01002706#define LOCKDEP_STATE(__STATE) \
2707 case LOCK_USED_IN_##__STATE: \
2708 case LOCK_USED_IN_##__STATE##_READ: \
2709 case LOCK_ENABLED_##__STATE: \
2710 case LOCK_ENABLED_##__STATE##_READ:
2711#include "lockdep_states.h"
2712#undef LOCKDEP_STATE
Peter Zijlstra8e182572007-07-19 01:48:54 -07002713 ret = mark_lock_irq(curr, this, new_bit);
2714 if (!ret)
2715 return 0;
2716 break;
2717 case LOCK_USED:
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002718 debug_atomic_dec(nr_unused_locks);
Peter Zijlstra8e182572007-07-19 01:48:54 -07002719 break;
2720 default:
2721 if (!debug_locks_off_graph_unlock())
2722 return 0;
2723 WARN_ON(1);
2724 return 0;
2725 }
2726
2727 graph_unlock();
2728
2729 /*
2730 * We must printk outside of the graph_lock:
2731 */
2732 if (ret == 2) {
2733 printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
2734 print_lock(this);
2735 print_irqtrace_events(curr);
2736 dump_stack();
2737 }
2738
2739 return ret;
2740}
2741
2742/*
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002743 * Initialize a lock instance's lock-class mapping info:
2744 */
2745void lockdep_init_map(struct lockdep_map *lock, const char *name,
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -04002746 struct lock_class_key *key, int subclass)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002747{
Hitoshi Mitake62016252010-10-05 18:01:51 +09002748 int i;
2749
2750 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
2751 lock->class_cache[i] = NULL;
2752
Peter Zijlstrac8a25002009-04-17 09:40:49 +02002753#ifdef CONFIG_LOCK_STAT
2754 lock->cpu = raw_smp_processor_id();
2755#endif
2756
2757 if (DEBUG_LOCKS_WARN_ON(!name)) {
2758 lock->name = "NULL";
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002759 return;
Peter Zijlstrac8a25002009-04-17 09:40:49 +02002760 }
2761
2762 lock->name = name;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002763
2764 if (DEBUG_LOCKS_WARN_ON(!key))
2765 return;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002766 /*
2767 * Sanity check, the lock-class key must be persistent:
2768 */
2769 if (!static_obj(key)) {
2770 printk("BUG: key %p not in .data!\n", key);
2771 DEBUG_LOCKS_WARN_ON(1);
2772 return;
2773 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002774 lock->key = key;
Peter Zijlstrac8a25002009-04-17 09:40:49 +02002775
2776 if (unlikely(!debug_locks))
2777 return;
2778
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -04002779 if (subclass)
2780 register_lock_class(lock, subclass, 1);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002781}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002782EXPORT_SYMBOL_GPL(lockdep_init_map);
2783
Peter Zijlstra1704f472010-03-19 01:37:42 +01002784struct lock_class_key __lockdep_no_validate__;
2785
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002786/*
2787 * This gets called for every mutex_lock*()/spin_lock*() operation.
2788 * We maintain the dependency maps and validate the locking attempt:
2789 */
2790static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
2791 int trylock, int read, int check, int hardirqs_off,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02002792 struct lockdep_map *nest_lock, unsigned long ip,
2793 int references)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002794{
2795 struct task_struct *curr = current;
Ingo Molnard6d897c2006-07-10 04:44:04 -07002796 struct lock_class *class = NULL;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002797 struct held_lock *hlock;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002798 unsigned int depth, id;
2799 int chain_head = 0;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02002800 int class_idx;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002801 u64 chain_key;
2802
Peter Zijlstraf20786f2007-07-19 01:48:56 -07002803 if (!prove_locking)
2804 check = 1;
2805
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002806 if (unlikely(!debug_locks))
2807 return 0;
2808
2809 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2810 return 0;
2811
Peter Zijlstra1704f472010-03-19 01:37:42 +01002812 if (lock->key == &__lockdep_no_validate__)
2813 check = 1;
2814
Hitoshi Mitake62016252010-10-05 18:01:51 +09002815 if (subclass < NR_LOCKDEP_CACHING_CLASSES)
2816 class = lock->class_cache[subclass];
Ingo Molnard6d897c2006-07-10 04:44:04 -07002817 /*
Hitoshi Mitake62016252010-10-05 18:01:51 +09002818 * Not cached?
Ingo Molnard6d897c2006-07-10 04:44:04 -07002819 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002820 if (unlikely(!class)) {
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -04002821 class = register_lock_class(lock, subclass, 0);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002822 if (!class)
2823 return 0;
2824 }
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002825 atomic_inc((atomic_t *)&class->ops);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002826 if (very_verbose(class)) {
2827 printk("\nacquire class [%p] %s", class->key, class->name);
2828 if (class->name_version > 1)
2829 printk("#%d", class->name_version);
2830 printk("\n");
2831 dump_stack();
2832 }
2833
2834 /*
2835 * Add the lock to the list of currently held locks.
2836 * (we dont increase the depth just yet, up until the
2837 * dependency checks are done)
2838 */
2839 depth = curr->lockdep_depth;
2840 if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
2841 return 0;
2842
Peter Zijlstrabb97a912009-07-20 19:15:35 +02002843 class_idx = class - lock_classes + 1;
2844
2845 if (depth) {
2846 hlock = curr->held_locks + depth - 1;
2847 if (hlock->class_idx == class_idx && nest_lock) {
2848 if (hlock->references)
2849 hlock->references++;
2850 else
2851 hlock->references = 2;
2852
2853 return 1;
2854 }
2855 }
2856
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002857 hlock = curr->held_locks + depth;
Dave Jonesf82b2172008-08-11 09:30:23 +02002858 if (DEBUG_LOCKS_WARN_ON(!class))
2859 return 0;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02002860 hlock->class_idx = class_idx;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002861 hlock->acquire_ip = ip;
2862 hlock->instance = lock;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02002863 hlock->nest_lock = nest_lock;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002864 hlock->trylock = trylock;
2865 hlock->read = read;
2866 hlock->check = check;
Dmitry Baryshkov6951b122008-08-18 04:26:37 +04002867 hlock->hardirqs_off = !!hardirqs_off;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02002868 hlock->references = references;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07002869#ifdef CONFIG_LOCK_STAT
2870 hlock->waittime_stamp = 0;
Peter Zijlstra3365e7792009-10-09 10:12:41 +02002871 hlock->holdtime_stamp = lockstat_clock();
Peter Zijlstraf20786f2007-07-19 01:48:56 -07002872#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002873
Peter Zijlstra8e182572007-07-19 01:48:54 -07002874 if (check == 2 && !mark_irqflags(curr, hlock))
2875 return 0;
2876
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002877 /* mark it as used: */
Jarek Poplawski4ff773bb2007-05-08 00:31:00 -07002878 if (!mark_lock(curr, hlock, LOCK_USED))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002879 return 0;
Peter Zijlstra8e182572007-07-19 01:48:54 -07002880
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002881 /*
Gautham R Shenoy17aacfb2007-10-28 20:47:01 +01002882 * Calculate the chain hash: it's the combined hash of all the
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002883 * lock keys along the dependency chain. We save the hash value
2884 * at every step so that we can get the current hash easily
2885 * after unlock. The chain hash is then used to cache dependency
2886 * results.
2887 *
2888 * The 'key ID' is what is the most compact key value to drive
2889 * the hash, not class->key.
2890 */
2891 id = class - lock_classes;
2892 if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
2893 return 0;
2894
2895 chain_key = curr->curr_chain_key;
2896 if (!depth) {
2897 if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
2898 return 0;
2899 chain_head = 1;
2900 }
2901
2902 hlock->prev_chain_key = chain_key;
Peter Zijlstra8e182572007-07-19 01:48:54 -07002903 if (separate_irq_context(curr, hlock)) {
2904 chain_key = 0;
2905 chain_head = 1;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002906 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002907 chain_key = iterate_chain_key(chain_key, id);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002908
Gregory Haskins3aa416b2007-10-11 22:11:11 +02002909 if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002910 return 0;
Jarek Poplawski381a2292007-02-10 01:44:58 -08002911
Gregory Haskins3aa416b2007-10-11 22:11:11 +02002912 curr->curr_chain_key = chain_key;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002913 curr->lockdep_depth++;
2914 check_chain_key(curr);
Jarek Poplawski60e114d2007-02-20 13:58:00 -08002915#ifdef CONFIG_DEBUG_LOCKDEP
2916 if (unlikely(!debug_locks))
2917 return 0;
2918#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002919 if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
2920 debug_locks_off();
2921 printk("BUG: MAX_LOCK_DEPTH too low!\n");
2922 printk("turning off the locking correctness validator.\n");
Peter Zijlstraeedeeab2009-03-18 12:38:47 +01002923 dump_stack();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002924 return 0;
2925 }
Jarek Poplawski381a2292007-02-10 01:44:58 -08002926
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002927 if (unlikely(curr->lockdep_depth > max_lockdep_depth))
2928 max_lockdep_depth = curr->lockdep_depth;
2929
2930 return 1;
2931}
2932
2933static int
2934print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
2935 unsigned long ip)
2936{
2937 if (!debug_locks_off())
2938 return 0;
2939 if (debug_locks_silent)
2940 return 0;
2941
2942 printk("\n=====================================\n");
2943 printk( "[ BUG: bad unlock balance detected! ]\n");
2944 printk( "-------------------------------------\n");
2945 printk("%s/%d is trying to release lock (",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07002946 curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002947 print_lockdep_cache(lock);
2948 printk(") at:\n");
2949 print_ip_sym(ip);
2950 printk("but there are no more locks to release!\n");
2951 printk("\nother info that might help us debug this:\n");
2952 lockdep_print_held_locks(curr);
2953
2954 printk("\nstack backtrace:\n");
2955 dump_stack();
2956
2957 return 0;
2958}
2959
2960/*
2961 * Common debugging checks for both nested and non-nested unlock:
2962 */
2963static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
2964 unsigned long ip)
2965{
2966 if (unlikely(!debug_locks))
2967 return 0;
2968 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2969 return 0;
2970
2971 if (curr->lockdep_depth <= 0)
2972 return print_unlock_inbalance_bug(curr, lock, ip);
2973
2974 return 1;
2975}
2976
Peter Zijlstrabb97a912009-07-20 19:15:35 +02002977static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
2978{
2979 if (hlock->instance == lock)
2980 return 1;
2981
2982 if (hlock->references) {
Hitoshi Mitake62016252010-10-05 18:01:51 +09002983 struct lock_class *class = lock->class_cache[0];
Peter Zijlstrabb97a912009-07-20 19:15:35 +02002984
2985 if (!class)
2986 class = look_up_lock_class(lock, 0);
2987
2988 if (DEBUG_LOCKS_WARN_ON(!class))
2989 return 0;
2990
2991 if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
2992 return 0;
2993
2994 if (hlock->class_idx == class - lock_classes + 1)
2995 return 1;
2996 }
2997
2998 return 0;
2999}
3000
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003001static int
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003002__lock_set_class(struct lockdep_map *lock, const char *name,
3003 struct lock_class_key *key, unsigned int subclass,
3004 unsigned long ip)
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003005{
3006 struct task_struct *curr = current;
3007 struct held_lock *hlock, *prev_hlock;
3008 struct lock_class *class;
3009 unsigned int depth;
3010 int i;
3011
3012 depth = curr->lockdep_depth;
3013 if (DEBUG_LOCKS_WARN_ON(!depth))
3014 return 0;
3015
3016 prev_hlock = NULL;
3017 for (i = depth-1; i >= 0; i--) {
3018 hlock = curr->held_locks + i;
3019 /*
3020 * We must not cross into another context:
3021 */
3022 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3023 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003024 if (match_held_lock(hlock, lock))
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003025 goto found_it;
3026 prev_hlock = hlock;
3027 }
3028 return print_unlock_inbalance_bug(curr, lock, ip);
3029
3030found_it:
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003031 lockdep_init_map(lock, name, key, 0);
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003032 class = register_lock_class(lock, subclass, 0);
Dave Jonesf82b2172008-08-11 09:30:23 +02003033 hlock->class_idx = class - lock_classes + 1;
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003034
3035 curr->lockdep_depth = i;
3036 curr->curr_chain_key = hlock->prev_chain_key;
3037
3038 for (; i < depth; i++) {
3039 hlock = curr->held_locks + i;
3040 if (!__lock_acquire(hlock->instance,
Dave Jonesf82b2172008-08-11 09:30:23 +02003041 hlock_class(hlock)->subclass, hlock->trylock,
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003042 hlock->read, hlock->check, hlock->hardirqs_off,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003043 hlock->nest_lock, hlock->acquire_ip,
3044 hlock->references))
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003045 return 0;
3046 }
3047
3048 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
3049 return 0;
3050 return 1;
3051}
3052
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003053/*
3054 * Remove the lock to the list of currently held locks in a
3055 * potentially non-nested (out of order) manner. This is a
3056 * relatively rare operation, as all the unlock APIs default
3057 * to nested mode (which uses lock_release()):
3058 */
3059static int
3060lock_release_non_nested(struct task_struct *curr,
3061 struct lockdep_map *lock, unsigned long ip)
3062{
3063 struct held_lock *hlock, *prev_hlock;
3064 unsigned int depth;
3065 int i;
3066
3067 /*
3068 * Check whether the lock exists in the current stack
3069 * of held locks:
3070 */
3071 depth = curr->lockdep_depth;
3072 if (DEBUG_LOCKS_WARN_ON(!depth))
3073 return 0;
3074
3075 prev_hlock = NULL;
3076 for (i = depth-1; i >= 0; i--) {
3077 hlock = curr->held_locks + i;
3078 /*
3079 * We must not cross into another context:
3080 */
3081 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3082 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003083 if (match_held_lock(hlock, lock))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003084 goto found_it;
3085 prev_hlock = hlock;
3086 }
3087 return print_unlock_inbalance_bug(curr, lock, ip);
3088
3089found_it:
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003090 if (hlock->instance == lock)
3091 lock_release_holdtime(hlock);
3092
3093 if (hlock->references) {
3094 hlock->references--;
3095 if (hlock->references) {
3096 /*
3097 * We had, and after removing one, still have
3098 * references, the current lock stack is still
3099 * valid. We're done!
3100 */
3101 return 1;
3102 }
3103 }
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003104
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003105 /*
3106 * We have the right lock to unlock, 'hlock' points to it.
3107 * Now we remove it from the stack, and add back the other
3108 * entries (if any), recalculating the hash along the way:
3109 */
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003110
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003111 curr->lockdep_depth = i;
3112 curr->curr_chain_key = hlock->prev_chain_key;
3113
3114 for (i++; i < depth; i++) {
3115 hlock = curr->held_locks + i;
3116 if (!__lock_acquire(hlock->instance,
Dave Jonesf82b2172008-08-11 09:30:23 +02003117 hlock_class(hlock)->subclass, hlock->trylock,
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003118 hlock->read, hlock->check, hlock->hardirqs_off,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003119 hlock->nest_lock, hlock->acquire_ip,
3120 hlock->references))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003121 return 0;
3122 }
3123
3124 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
3125 return 0;
3126 return 1;
3127}
3128
3129/*
3130 * Remove the lock to the list of currently held locks - this gets
3131 * called on mutex_unlock()/spin_unlock*() (or on a failed
3132 * mutex_lock_interruptible()). This is done for unlocks that nest
3133 * perfectly. (i.e. the current top of the lock-stack is unlocked)
3134 */
3135static int lock_release_nested(struct task_struct *curr,
3136 struct lockdep_map *lock, unsigned long ip)
3137{
3138 struct held_lock *hlock;
3139 unsigned int depth;
3140
3141 /*
3142 * Pop off the top of the lock stack:
3143 */
3144 depth = curr->lockdep_depth - 1;
3145 hlock = curr->held_locks + depth;
3146
3147 /*
3148 * Is the unlock non-nested:
3149 */
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003150 if (hlock->instance != lock || hlock->references)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003151 return lock_release_non_nested(curr, lock, ip);
3152 curr->lockdep_depth--;
3153
3154 if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
3155 return 0;
3156
3157 curr->curr_chain_key = hlock->prev_chain_key;
3158
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003159 lock_release_holdtime(hlock);
3160
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003161#ifdef CONFIG_DEBUG_LOCKDEP
3162 hlock->prev_chain_key = 0;
Dave Jonesf82b2172008-08-11 09:30:23 +02003163 hlock->class_idx = 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003164 hlock->acquire_ip = 0;
3165 hlock->irq_context = 0;
3166#endif
3167 return 1;
3168}
3169
3170/*
3171 * Remove the lock to the list of currently held locks - this gets
3172 * called on mutex_unlock()/spin_unlock*() (or on a failed
3173 * mutex_lock_interruptible()). This is done for unlocks that nest
3174 * perfectly. (i.e. the current top of the lock-stack is unlocked)
3175 */
3176static void
3177__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
3178{
3179 struct task_struct *curr = current;
3180
3181 if (!check_unlock(curr, lock, ip))
3182 return;
3183
3184 if (nested) {
3185 if (!lock_release_nested(curr, lock, ip))
3186 return;
3187 } else {
3188 if (!lock_release_non_nested(curr, lock, ip))
3189 return;
3190 }
3191
3192 check_chain_key(curr);
3193}
3194
Peter Zijlstraf607c662009-07-20 19:16:29 +02003195static int __lock_is_held(struct lockdep_map *lock)
3196{
3197 struct task_struct *curr = current;
3198 int i;
3199
3200 for (i = 0; i < curr->lockdep_depth; i++) {
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003201 struct held_lock *hlock = curr->held_locks + i;
3202
3203 if (match_held_lock(hlock, lock))
Peter Zijlstraf607c662009-07-20 19:16:29 +02003204 return 1;
3205 }
3206
3207 return 0;
3208}
3209
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003210/*
3211 * Check whether we follow the irq-flags state precisely:
3212 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02003213static void check_flags(unsigned long flags)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003214{
Ingo Molnar992860e2008-07-14 10:28:38 +02003215#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
3216 defined(CONFIG_TRACE_IRQFLAGS)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003217 if (!debug_locks)
3218 return;
3219
Ingo Molnar5f9fa8a2007-12-07 19:02:47 +01003220 if (irqs_disabled_flags(flags)) {
3221 if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
3222 printk("possible reason: unannotated irqs-off.\n");
3223 }
3224 } else {
3225 if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
3226 printk("possible reason: unannotated irqs-on.\n");
3227 }
3228 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003229
3230 /*
3231 * We dont accurately track softirq state in e.g.
3232 * hardirq contexts (such as on 4KSTACKS), so only
3233 * check if not in hardirq contexts:
3234 */
3235 if (!hardirq_count()) {
3236 if (softirq_count())
3237 DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
3238 else
3239 DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
3240 }
3241
3242 if (!debug_locks)
3243 print_irqtrace_events(current);
3244#endif
3245}
3246
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003247void lock_set_class(struct lockdep_map *lock, const char *name,
3248 struct lock_class_key *key, unsigned int subclass,
3249 unsigned long ip)
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003250{
3251 unsigned long flags;
3252
3253 if (unlikely(current->lockdep_recursion))
3254 return;
3255
3256 raw_local_irq_save(flags);
3257 current->lockdep_recursion = 1;
3258 check_flags(flags);
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003259 if (__lock_set_class(lock, name, key, subclass, ip))
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003260 check_chain_key(current);
3261 current->lockdep_recursion = 0;
3262 raw_local_irq_restore(flags);
3263}
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003264EXPORT_SYMBOL_GPL(lock_set_class);
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003265
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003266/*
3267 * We are not always called with irqs disabled - do that here,
3268 * and also avoid lockdep recursion:
3269 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02003270void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02003271 int trylock, int read, int check,
3272 struct lockdep_map *nest_lock, unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003273{
3274 unsigned long flags;
3275
3276 if (unlikely(current->lockdep_recursion))
3277 return;
3278
3279 raw_local_irq_save(flags);
3280 check_flags(flags);
3281
3282 current->lockdep_recursion = 1;
Frederic Weisbeckerdb2c4c72010-02-02 23:34:40 +01003283 trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003284 __lock_acquire(lock, subclass, trylock, read, check,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003285 irqs_disabled_flags(flags), nest_lock, ip, 0);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003286 current->lockdep_recursion = 0;
3287 raw_local_irq_restore(flags);
3288}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003289EXPORT_SYMBOL_GPL(lock_acquire);
3290
Steven Rostedt1d09daa2008-05-12 21:20:55 +02003291void lock_release(struct lockdep_map *lock, int nested,
Steven Rostedt0764d232008-05-12 21:20:44 +02003292 unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003293{
3294 unsigned long flags;
3295
3296 if (unlikely(current->lockdep_recursion))
3297 return;
3298
3299 raw_local_irq_save(flags);
3300 check_flags(flags);
3301 current->lockdep_recursion = 1;
Frederic Weisbecker93135432010-05-08 06:24:25 +02003302 trace_lock_release(lock, ip);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003303 __lock_release(lock, nested, ip);
3304 current->lockdep_recursion = 0;
3305 raw_local_irq_restore(flags);
3306}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003307EXPORT_SYMBOL_GPL(lock_release);
3308
Peter Zijlstraf607c662009-07-20 19:16:29 +02003309int lock_is_held(struct lockdep_map *lock)
3310{
3311 unsigned long flags;
3312 int ret = 0;
3313
3314 if (unlikely(current->lockdep_recursion))
3315 return ret;
3316
3317 raw_local_irq_save(flags);
3318 check_flags(flags);
3319
3320 current->lockdep_recursion = 1;
3321 ret = __lock_is_held(lock);
3322 current->lockdep_recursion = 0;
3323 raw_local_irq_restore(flags);
3324
3325 return ret;
3326}
3327EXPORT_SYMBOL_GPL(lock_is_held);
3328
Nick Piggincf40bd12009-01-21 08:12:39 +01003329void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
3330{
3331 current->lockdep_reclaim_gfp = gfp_mask;
3332}
3333
3334void lockdep_clear_current_reclaim_state(void)
3335{
3336 current->lockdep_reclaim_gfp = 0;
3337}
3338
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003339#ifdef CONFIG_LOCK_STAT
3340static int
3341print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
3342 unsigned long ip)
3343{
3344 if (!debug_locks_off())
3345 return 0;
3346 if (debug_locks_silent)
3347 return 0;
3348
3349 printk("\n=================================\n");
3350 printk( "[ BUG: bad contention detected! ]\n");
3351 printk( "---------------------------------\n");
3352 printk("%s/%d is trying to contend lock (",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07003353 curr->comm, task_pid_nr(curr));
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003354 print_lockdep_cache(lock);
3355 printk(") at:\n");
3356 print_ip_sym(ip);
3357 printk("but there are no locks held!\n");
3358 printk("\nother info that might help us debug this:\n");
3359 lockdep_print_held_locks(curr);
3360
3361 printk("\nstack backtrace:\n");
3362 dump_stack();
3363
3364 return 0;
3365}
3366
3367static void
3368__lock_contended(struct lockdep_map *lock, unsigned long ip)
3369{
3370 struct task_struct *curr = current;
3371 struct held_lock *hlock, *prev_hlock;
3372 struct lock_class_stats *stats;
3373 unsigned int depth;
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003374 int i, contention_point, contending_point;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003375
3376 depth = curr->lockdep_depth;
3377 if (DEBUG_LOCKS_WARN_ON(!depth))
3378 return;
3379
3380 prev_hlock = NULL;
3381 for (i = depth-1; i >= 0; i--) {
3382 hlock = curr->held_locks + i;
3383 /*
3384 * We must not cross into another context:
3385 */
3386 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3387 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003388 if (match_held_lock(hlock, lock))
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003389 goto found_it;
3390 prev_hlock = hlock;
3391 }
3392 print_lock_contention_bug(curr, lock, ip);
3393 return;
3394
3395found_it:
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003396 if (hlock->instance != lock)
3397 return;
3398
Peter Zijlstra3365e7792009-10-09 10:12:41 +02003399 hlock->waittime_stamp = lockstat_clock();
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003400
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003401 contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
3402 contending_point = lock_point(hlock_class(hlock)->contending_point,
3403 lock->ip);
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003404
Dave Jonesf82b2172008-08-11 09:30:23 +02003405 stats = get_lock_stats(hlock_class(hlock));
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003406 if (contention_point < LOCKSTAT_POINTS)
3407 stats->contention_point[contention_point]++;
3408 if (contending_point < LOCKSTAT_POINTS)
3409 stats->contending_point[contending_point]++;
Peter Zijlstra96645672007-07-19 01:49:00 -07003410 if (lock->cpu != smp_processor_id())
3411 stats->bounces[bounce_contended + !!hlock->read]++;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003412 put_lock_stats(stats);
3413}
3414
3415static void
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003416__lock_acquired(struct lockdep_map *lock, unsigned long ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003417{
3418 struct task_struct *curr = current;
3419 struct held_lock *hlock, *prev_hlock;
3420 struct lock_class_stats *stats;
3421 unsigned int depth;
Peter Zijlstra3365e7792009-10-09 10:12:41 +02003422 u64 now, waittime = 0;
Peter Zijlstra96645672007-07-19 01:49:00 -07003423 int i, cpu;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003424
3425 depth = curr->lockdep_depth;
3426 if (DEBUG_LOCKS_WARN_ON(!depth))
3427 return;
3428
3429 prev_hlock = NULL;
3430 for (i = depth-1; i >= 0; i--) {
3431 hlock = curr->held_locks + i;
3432 /*
3433 * We must not cross into another context:
3434 */
3435 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3436 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003437 if (match_held_lock(hlock, lock))
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003438 goto found_it;
3439 prev_hlock = hlock;
3440 }
3441 print_lock_contention_bug(curr, lock, _RET_IP_);
3442 return;
3443
3444found_it:
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003445 if (hlock->instance != lock)
3446 return;
3447
Peter Zijlstra96645672007-07-19 01:49:00 -07003448 cpu = smp_processor_id();
3449 if (hlock->waittime_stamp) {
Peter Zijlstra3365e7792009-10-09 10:12:41 +02003450 now = lockstat_clock();
Peter Zijlstra96645672007-07-19 01:49:00 -07003451 waittime = now - hlock->waittime_stamp;
3452 hlock->holdtime_stamp = now;
3453 }
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003454
Frederic Weisbecker883a2a32010-05-08 06:16:11 +02003455 trace_lock_acquired(lock, ip);
Frederic Weisbecker20625012009-04-06 01:49:33 +02003456
Dave Jonesf82b2172008-08-11 09:30:23 +02003457 stats = get_lock_stats(hlock_class(hlock));
Peter Zijlstra96645672007-07-19 01:49:00 -07003458 if (waittime) {
3459 if (hlock->read)
3460 lock_time_inc(&stats->read_waittime, waittime);
3461 else
3462 lock_time_inc(&stats->write_waittime, waittime);
3463 }
3464 if (lock->cpu != cpu)
3465 stats->bounces[bounce_acquired + !!hlock->read]++;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003466 put_lock_stats(stats);
Peter Zijlstra96645672007-07-19 01:49:00 -07003467
3468 lock->cpu = cpu;
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003469 lock->ip = ip;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003470}
3471
3472void lock_contended(struct lockdep_map *lock, unsigned long ip)
3473{
3474 unsigned long flags;
3475
3476 if (unlikely(!lock_stat))
3477 return;
3478
3479 if (unlikely(current->lockdep_recursion))
3480 return;
3481
3482 raw_local_irq_save(flags);
3483 check_flags(flags);
3484 current->lockdep_recursion = 1;
Frederic Weisbeckerdb2c4c72010-02-02 23:34:40 +01003485 trace_lock_contended(lock, ip);
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003486 __lock_contended(lock, ip);
3487 current->lockdep_recursion = 0;
3488 raw_local_irq_restore(flags);
3489}
3490EXPORT_SYMBOL_GPL(lock_contended);
3491
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003492void lock_acquired(struct lockdep_map *lock, unsigned long ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003493{
3494 unsigned long flags;
3495
3496 if (unlikely(!lock_stat))
3497 return;
3498
3499 if (unlikely(current->lockdep_recursion))
3500 return;
3501
3502 raw_local_irq_save(flags);
3503 check_flags(flags);
3504 current->lockdep_recursion = 1;
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003505 __lock_acquired(lock, ip);
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003506 current->lockdep_recursion = 0;
3507 raw_local_irq_restore(flags);
3508}
3509EXPORT_SYMBOL_GPL(lock_acquired);
3510#endif
3511
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003512/*
3513 * Used by the testsuite, sanitize the validator state
3514 * after a simulated failure:
3515 */
3516
3517void lockdep_reset(void)
3518{
3519 unsigned long flags;
Ingo Molnar23d95a02006-12-13 00:34:40 -08003520 int i;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003521
3522 raw_local_irq_save(flags);
3523 current->curr_chain_key = 0;
3524 current->lockdep_depth = 0;
3525 current->lockdep_recursion = 0;
3526 memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
3527 nr_hardirq_chains = 0;
3528 nr_softirq_chains = 0;
3529 nr_process_chains = 0;
3530 debug_locks = 1;
Ingo Molnar23d95a02006-12-13 00:34:40 -08003531 for (i = 0; i < CHAINHASH_SIZE; i++)
3532 INIT_LIST_HEAD(chainhash_table + i);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003533 raw_local_irq_restore(flags);
3534}
3535
3536static void zap_class(struct lock_class *class)
3537{
3538 int i;
3539
3540 /*
3541 * Remove all dependencies this lock is
3542 * involved in:
3543 */
3544 for (i = 0; i < nr_list_entries; i++) {
3545 if (list_entries[i].class == class)
3546 list_del_rcu(&list_entries[i].entry);
3547 }
3548 /*
3549 * Unhash the class and remove it from the all_lock_classes list:
3550 */
3551 list_del_rcu(&class->hash_entry);
3552 list_del_rcu(&class->lock_entry);
3553
Rabin Vincent8bfe0292008-08-11 09:30:26 +02003554 class->key = NULL;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003555}
3556
Arjan van de Venfabe8742008-01-24 07:00:45 +01003557static inline int within(const void *addr, void *start, unsigned long size)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003558{
3559 return addr >= start && addr < start + size;
3560}
3561
3562void lockdep_free_key_range(void *start, unsigned long size)
3563{
3564 struct lock_class *class, *next;
3565 struct list_head *head;
3566 unsigned long flags;
3567 int i;
Nick Piggin5a26db52008-01-16 09:51:58 +01003568 int locked;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003569
3570 raw_local_irq_save(flags);
Nick Piggin5a26db52008-01-16 09:51:58 +01003571 locked = graph_lock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003572
3573 /*
3574 * Unhash all classes that were created by this module:
3575 */
3576 for (i = 0; i < CLASSHASH_SIZE; i++) {
3577 head = classhash_table + i;
3578 if (list_empty(head))
3579 continue;
Arjan van de Venfabe8742008-01-24 07:00:45 +01003580 list_for_each_entry_safe(class, next, head, hash_entry) {
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003581 if (within(class->key, start, size))
3582 zap_class(class);
Arjan van de Venfabe8742008-01-24 07:00:45 +01003583 else if (within(class->name, start, size))
3584 zap_class(class);
3585 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003586 }
3587
Nick Piggin5a26db52008-01-16 09:51:58 +01003588 if (locked)
3589 graph_unlock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003590 raw_local_irq_restore(flags);
3591}
3592
3593void lockdep_reset_lock(struct lockdep_map *lock)
3594{
Ingo Molnard6d897c2006-07-10 04:44:04 -07003595 struct lock_class *class, *next;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003596 struct list_head *head;
3597 unsigned long flags;
3598 int i, j;
Nick Piggin5a26db52008-01-16 09:51:58 +01003599 int locked;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003600
3601 raw_local_irq_save(flags);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003602
3603 /*
Ingo Molnard6d897c2006-07-10 04:44:04 -07003604 * Remove all classes this lock might have:
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003605 */
Ingo Molnard6d897c2006-07-10 04:44:04 -07003606 for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
3607 /*
3608 * If the class exists we look it up and zap it:
3609 */
3610 class = look_up_lock_class(lock, j);
3611 if (class)
3612 zap_class(class);
3613 }
3614 /*
3615 * Debug check: in the end all mapped classes should
3616 * be gone.
3617 */
Nick Piggin5a26db52008-01-16 09:51:58 +01003618 locked = graph_lock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003619 for (i = 0; i < CLASSHASH_SIZE; i++) {
3620 head = classhash_table + i;
3621 if (list_empty(head))
3622 continue;
3623 list_for_each_entry_safe(class, next, head, hash_entry) {
Hitoshi Mitake62016252010-10-05 18:01:51 +09003624 int match = 0;
3625
3626 for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
3627 match |= class == lock->class_cache[j];
3628
3629 if (unlikely(match)) {
Ingo Molnar74c383f2006-12-13 00:34:43 -08003630 if (debug_locks_off_graph_unlock())
3631 WARN_ON(1);
Ingo Molnard6d897c2006-07-10 04:44:04 -07003632 goto out_restore;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003633 }
3634 }
3635 }
Nick Piggin5a26db52008-01-16 09:51:58 +01003636 if (locked)
3637 graph_unlock();
Ingo Molnard6d897c2006-07-10 04:44:04 -07003638
3639out_restore:
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003640 raw_local_irq_restore(flags);
3641}
3642
Sam Ravnborg14999932007-02-28 20:12:31 -08003643void lockdep_init(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003644{
3645 int i;
3646
3647 /*
3648 * Some architectures have their own start_kernel()
3649 * code which calls lockdep_init(), while we also
3650 * call lockdep_init() from the start_kernel() itself,
3651 * and we want to initialize the hashes only once:
3652 */
3653 if (lockdep_initialized)
3654 return;
3655
3656 for (i = 0; i < CLASSHASH_SIZE; i++)
3657 INIT_LIST_HEAD(classhash_table + i);
3658
3659 for (i = 0; i < CHAINHASH_SIZE; i++)
3660 INIT_LIST_HEAD(chainhash_table + i);
3661
3662 lockdep_initialized = 1;
3663}
3664
3665void __init lockdep_info(void)
3666{
3667 printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
3668
Li Zefanb0788ca2008-11-21 15:57:32 +08003669 printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003670 printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
3671 printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
Li Zefanb0788ca2008-11-21 15:57:32 +08003672 printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003673 printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
3674 printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
3675 printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
3676
3677 printk(" memory used by lock dependency info: %lu kB\n",
3678 (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
3679 sizeof(struct list_head) * CLASSHASH_SIZE +
3680 sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
3681 sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
Ming Lei90629202009-08-02 21:43:36 +08003682 sizeof(struct list_head) * CHAINHASH_SIZE
Ming Lei4dd861d2009-07-16 15:44:29 +02003683#ifdef CONFIG_PROVE_LOCKING
Ming Leie351b662009-07-22 22:48:09 +08003684 + sizeof(struct circular_queue)
Ming Lei4dd861d2009-07-16 15:44:29 +02003685#endif
Ming Lei90629202009-08-02 21:43:36 +08003686 ) / 1024
Ming Lei4dd861d2009-07-16 15:44:29 +02003687 );
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003688
3689 printk(" per task-struct memory footprint: %lu bytes\n",
3690 sizeof(struct held_lock) * MAX_LOCK_DEPTH);
3691
3692#ifdef CONFIG_DEBUG_LOCKDEP
Johannes Bergc71063c2007-07-19 01:49:02 -07003693 if (lockdep_init_error) {
3694 printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
3695 printk("Call stack leading to lockdep invocation was:\n");
3696 print_stack_trace(&lockdep_init_trace, 0);
3697 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003698#endif
3699}
3700
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003701static void
3702print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
Arjan van de Ven55794a42006-07-10 04:44:03 -07003703 const void *mem_to, struct held_lock *hlock)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003704{
3705 if (!debug_locks_off())
3706 return;
3707 if (debug_locks_silent)
3708 return;
3709
3710 printk("\n=========================\n");
3711 printk( "[ BUG: held lock freed! ]\n");
3712 printk( "-------------------------\n");
3713 printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07003714 curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
Arjan van de Ven55794a42006-07-10 04:44:03 -07003715 print_lock(hlock);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003716 lockdep_print_held_locks(curr);
3717
3718 printk("\nstack backtrace:\n");
3719 dump_stack();
3720}
3721
Oleg Nesterov54561782007-12-05 15:46:09 +01003722static inline int not_in_range(const void* mem_from, unsigned long mem_len,
3723 const void* lock_from, unsigned long lock_len)
3724{
3725 return lock_from + lock_len <= mem_from ||
3726 mem_from + mem_len <= lock_from;
3727}
3728
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003729/*
3730 * Called when kernel memory is freed (or unmapped), or if a lock
3731 * is destroyed or reinitialized - this code checks whether there is
3732 * any held lock in the memory range of <from> to <to>:
3733 */
3734void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
3735{
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003736 struct task_struct *curr = current;
3737 struct held_lock *hlock;
3738 unsigned long flags;
3739 int i;
3740
3741 if (unlikely(!debug_locks))
3742 return;
3743
3744 local_irq_save(flags);
3745 for (i = 0; i < curr->lockdep_depth; i++) {
3746 hlock = curr->held_locks + i;
3747
Oleg Nesterov54561782007-12-05 15:46:09 +01003748 if (not_in_range(mem_from, mem_len, hlock->instance,
3749 sizeof(*hlock->instance)))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003750 continue;
3751
Oleg Nesterov54561782007-12-05 15:46:09 +01003752 print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003753 break;
3754 }
3755 local_irq_restore(flags);
3756}
Peter Zijlstraed075362006-12-06 20:35:24 -08003757EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003758
3759static void print_held_locks_bug(struct task_struct *curr)
3760{
3761 if (!debug_locks_off())
3762 return;
3763 if (debug_locks_silent)
3764 return;
3765
3766 printk("\n=====================================\n");
3767 printk( "[ BUG: lock held at task exit time! ]\n");
3768 printk( "-------------------------------------\n");
3769 printk("%s/%d is exiting with locks still held!\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07003770 curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003771 lockdep_print_held_locks(curr);
3772
3773 printk("\nstack backtrace:\n");
3774 dump_stack();
3775}
3776
3777void debug_check_no_locks_held(struct task_struct *task)
3778{
3779 if (unlikely(task->lockdep_depth > 0))
3780 print_held_locks_bug(task);
3781}
3782
3783void debug_show_all_locks(void)
3784{
3785 struct task_struct *g, *p;
3786 int count = 10;
3787 int unlock = 1;
3788
Jarek Poplawski9c35dd72007-03-22 00:11:28 -08003789 if (unlikely(!debug_locks)) {
3790 printk("INFO: lockdep is turned off.\n");
3791 return;
3792 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003793 printk("\nShowing all locks held in the system:\n");
3794
3795 /*
3796 * Here we try to get the tasklist_lock as hard as possible,
3797 * if not successful after 2 seconds we ignore it (but keep
3798 * trying). This is to enable a debug printout even if a
3799 * tasklist_lock-holding task deadlocks or crashes.
3800 */
3801retry:
3802 if (!read_trylock(&tasklist_lock)) {
3803 if (count == 10)
3804 printk("hm, tasklist_lock locked, retrying... ");
3805 if (count) {
3806 count--;
3807 printk(" #%d", 10-count);
3808 mdelay(200);
3809 goto retry;
3810 }
3811 printk(" ignoring it.\n");
3812 unlock = 0;
qinghuang feng46fec7a2008-10-28 17:24:28 +08003813 } else {
3814 if (count != 10)
3815 printk(KERN_CONT " locked it.\n");
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003816 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003817
3818 do_each_thread(g, p) {
Ingo Molnar85684872007-12-05 15:46:09 +01003819 /*
3820 * It's not reliable to print a task's held locks
3821 * if it's not sleeping (or if it's not the current
3822 * task):
3823 */
3824 if (p->state == TASK_RUNNING && p != current)
3825 continue;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003826 if (p->lockdep_depth)
3827 lockdep_print_held_locks(p);
3828 if (!unlock)
3829 if (read_trylock(&tasklist_lock))
3830 unlock = 1;
3831 } while_each_thread(g, p);
3832
3833 printk("\n");
3834 printk("=============================================\n\n");
3835
3836 if (unlock)
3837 read_unlock(&tasklist_lock);
3838}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003839EXPORT_SYMBOL_GPL(debug_show_all_locks);
3840
Ingo Molnar82a1fcb2008-01-25 21:08:02 +01003841/*
3842 * Careful: only use this function if you are sure that
3843 * the task cannot run in parallel!
3844 */
John Kacurf1b499f2010-08-05 17:10:53 +02003845void debug_show_held_locks(struct task_struct *task)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003846{
Jarek Poplawski9c35dd72007-03-22 00:11:28 -08003847 if (unlikely(!debug_locks)) {
3848 printk("INFO: lockdep is turned off.\n");
3849 return;
3850 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003851 lockdep_print_held_locks(task);
3852}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003853EXPORT_SYMBOL_GPL(debug_show_held_locks);
Peter Zijlstrab351d162007-10-11 22:11:12 +02003854
3855void lockdep_sys_exit(void)
3856{
3857 struct task_struct *curr = current;
3858
3859 if (unlikely(curr->lockdep_depth)) {
3860 if (!debug_locks_off())
3861 return;
3862 printk("\n================================================\n");
3863 printk( "[ BUG: lock held when returning to user space! ]\n");
3864 printk( "------------------------------------------------\n");
3865 printk("%s/%d is leaving the kernel with locks still held!\n",
3866 curr->comm, curr->pid);
3867 lockdep_print_held_locks(curr);
3868 }
3869}
Paul E. McKenney0632eb32010-02-22 17:04:47 -08003870
3871void lockdep_rcu_dereference(const char *file, const int line)
3872{
3873 struct task_struct *curr = current;
3874
Lai Jiangshan2b3fc352010-04-20 16:23:07 +08003875#ifndef CONFIG_PROVE_RCU_REPEATEDLY
Paul E. McKenney0632eb32010-02-22 17:04:47 -08003876 if (!debug_locks_off())
3877 return;
Lai Jiangshan2b3fc352010-04-20 16:23:07 +08003878#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
3879 /* Note: the following can be executed concurrently, so be careful. */
Paul E. McKenney056ba4a2010-02-25 14:06:46 -08003880 printk("\n===================================================\n");
3881 printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n");
3882 printk( "---------------------------------------------------\n");
Paul E. McKenney0632eb32010-02-22 17:04:47 -08003883 printk("%s:%d invoked rcu_dereference_check() without protection!\n",
3884 file, line);
3885 printk("\nother info that might help us debug this:\n\n");
Paul E. McKenneycc5b83a2010-03-03 07:46:59 -08003886 printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks);
Paul E. McKenney0632eb32010-02-22 17:04:47 -08003887 lockdep_print_held_locks(curr);
3888 printk("\nstack backtrace:\n");
3889 dump_stack();
3890}
3891EXPORT_SYMBOL_GPL(lockdep_rcu_dereference);