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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>
Yong Zhangd3d03d42011-11-09 16:04:51 +080047#include <linux/kmemcheck.h>
Peter Zijlstraaf012962009-07-16 15:44:29 +020048
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070049#include <asm/sections.h>
50
51#include "lockdep_internals.h"
52
Steven Rostedta8d154b2009-04-10 09:36:00 -040053#define CREATE_TRACE_POINTS
Frederic Weisbecker67178762009-11-13 10:06:34 +010054#include <trace/events/lock.h>
Steven Rostedta8d154b2009-04-10 09:36:00 -040055
Peter Zijlstraf20786f2007-07-19 01:48:56 -070056#ifdef CONFIG_PROVE_LOCKING
57int prove_locking = 1;
58module_param(prove_locking, int, 0644);
59#else
60#define prove_locking 0
61#endif
62
63#ifdef CONFIG_LOCK_STAT
64int lock_stat = 1;
65module_param(lock_stat, int, 0644);
66#else
67#define lock_stat 0
68#endif
69
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070070/*
Ingo Molnar74c383f2006-12-13 00:34:43 -080071 * lockdep_lock: protects the lockdep graph, the hashes and the
72 * class/list/hash allocators.
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070073 *
74 * This is one of the rare exceptions where it's justified
75 * to use a raw spinlock - we really dont want the spinlock
Ingo Molnar74c383f2006-12-13 00:34:43 -080076 * code to recurse back into the lockdep code...
Ingo Molnarfbb9ce952006-07-03 00:24:50 -070077 */
Thomas Gleixneredc35bd2009-12-03 12:38:57 +010078static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
Ingo Molnar74c383f2006-12-13 00:34:43 -080079
80static int graph_lock(void)
81{
Thomas Gleixner0199c4e2009-12-02 20:01:25 +010082 arch_spin_lock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -080083 /*
84 * Make sure that if another CPU detected a bug while
85 * walking the graph we dont change it (while the other
86 * CPU is busy printing out stuff with the graph lock
87 * dropped already)
88 */
89 if (!debug_locks) {
Thomas Gleixner0199c4e2009-12-02 20:01:25 +010090 arch_spin_unlock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -080091 return 0;
92 }
Steven Rostedtbb065af2008-05-12 21:21:00 +020093 /* prevent any recursions within lockdep from causing deadlocks */
94 current->lockdep_recursion++;
Ingo Molnar74c383f2006-12-13 00:34:43 -080095 return 1;
96}
97
98static inline int graph_unlock(void)
99{
Peter Zijlstra0119fee2011-09-02 01:30:29 +0200100 if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) {
101 /*
102 * The lockdep graph lock isn't locked while we expect it to
103 * be, we're confused now, bye!
104 */
Jarek Poplawski381a2292007-02-10 01:44:58 -0800105 return DEBUG_LOCKS_WARN_ON(1);
Peter Zijlstra0119fee2011-09-02 01:30:29 +0200106 }
Jarek Poplawski381a2292007-02-10 01:44:58 -0800107
Steven Rostedtbb065af2008-05-12 21:21:00 +0200108 current->lockdep_recursion--;
Thomas Gleixner0199c4e2009-12-02 20:01:25 +0100109 arch_spin_unlock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800110 return 0;
111}
112
113/*
114 * Turn lock debugging off and return with 0 if it was off already,
115 * and also release the graph lock:
116 */
117static inline int debug_locks_off_graph_unlock(void)
118{
119 int ret = debug_locks_off();
120
Thomas Gleixner0199c4e2009-12-02 20:01:25 +0100121 arch_spin_unlock(&lockdep_lock);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800122
123 return ret;
124}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700125
126static int lockdep_initialized;
127
128unsigned long nr_list_entries;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200129static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700130
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700131/*
132 * All data structures here are protected by the global debug_lock.
133 *
134 * Mutex key structs only get allocated, once during bootup, and never
135 * get freed - this significantly simplifies the debugging code.
136 */
137unsigned long nr_lock_classes;
138static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
139
Dave Jonesf82b2172008-08-11 09:30:23 +0200140static inline struct lock_class *hlock_class(struct held_lock *hlock)
141{
142 if (!hlock->class_idx) {
Peter Zijlstra0119fee2011-09-02 01:30:29 +0200143 /*
144 * Someone passed in garbage, we give up.
145 */
Dave Jonesf82b2172008-08-11 09:30:23 +0200146 DEBUG_LOCKS_WARN_ON(1);
147 return NULL;
148 }
149 return lock_classes + hlock->class_idx - 1;
150}
151
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700152#ifdef CONFIG_LOCK_STAT
Tejun Heo1871e522009-10-29 22:34:13 +0900153static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS],
154 cpu_lock_stats);
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700155
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200156static inline u64 lockstat_clock(void)
157{
Peter Zijlstrac6763292010-05-25 10:48:51 +0200158 return local_clock();
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200159}
160
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200161static int lock_point(unsigned long points[], unsigned long ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700162{
163 int i;
164
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200165 for (i = 0; i < LOCKSTAT_POINTS; i++) {
166 if (points[i] == 0) {
167 points[i] = ip;
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700168 break;
169 }
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200170 if (points[i] == ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700171 break;
172 }
173
174 return i;
175}
176
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200177static void lock_time_inc(struct lock_time *lt, u64 time)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700178{
179 if (time > lt->max)
180 lt->max = time;
181
Frank Rowand109d71c2009-11-19 13:42:06 -0800182 if (time < lt->min || !lt->nr)
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700183 lt->min = time;
184
185 lt->total += time;
186 lt->nr++;
187}
188
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700189static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
190{
Frank Rowand109d71c2009-11-19 13:42:06 -0800191 if (!src->nr)
192 return;
193
194 if (src->max > dst->max)
195 dst->max = src->max;
196
197 if (src->min < dst->min || !dst->nr)
198 dst->min = src->min;
199
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700200 dst->total += src->total;
201 dst->nr += src->nr;
202}
203
204struct lock_class_stats lock_stats(struct lock_class *class)
205{
206 struct lock_class_stats stats;
207 int cpu, i;
208
209 memset(&stats, 0, sizeof(struct lock_class_stats));
210 for_each_possible_cpu(cpu) {
211 struct lock_class_stats *pcs =
Tejun Heo1871e522009-10-29 22:34:13 +0900212 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700213
214 for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
215 stats.contention_point[i] += pcs->contention_point[i];
216
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200217 for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++)
218 stats.contending_point[i] += pcs->contending_point[i];
219
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700220 lock_time_add(&pcs->read_waittime, &stats.read_waittime);
221 lock_time_add(&pcs->write_waittime, &stats.write_waittime);
222
223 lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
224 lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
Peter Zijlstra96645672007-07-19 01:49:00 -0700225
226 for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
227 stats.bounces[i] += pcs->bounces[i];
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700228 }
229
230 return stats;
231}
232
233void clear_lock_stats(struct lock_class *class)
234{
235 int cpu;
236
237 for_each_possible_cpu(cpu) {
238 struct lock_class_stats *cpu_stats =
Tejun Heo1871e522009-10-29 22:34:13 +0900239 &per_cpu(cpu_lock_stats, cpu)[class - lock_classes];
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700240
241 memset(cpu_stats, 0, sizeof(struct lock_class_stats));
242 }
243 memset(class->contention_point, 0, sizeof(class->contention_point));
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +0200244 memset(class->contending_point, 0, sizeof(class->contending_point));
Peter Zijlstrac46261d2007-07-19 01:48:57 -0700245}
246
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700247static struct lock_class_stats *get_lock_stats(struct lock_class *class)
248{
Tejun Heo1871e522009-10-29 22:34:13 +0900249 return &get_cpu_var(cpu_lock_stats)[class - lock_classes];
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700250}
251
252static void put_lock_stats(struct lock_class_stats *stats)
253{
Tejun Heo1871e522009-10-29 22:34:13 +0900254 put_cpu_var(cpu_lock_stats);
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700255}
256
257static void lock_release_holdtime(struct held_lock *hlock)
258{
259 struct lock_class_stats *stats;
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200260 u64 holdtime;
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700261
262 if (!lock_stat)
263 return;
264
Peter Zijlstra3365e7792009-10-09 10:12:41 +0200265 holdtime = lockstat_clock() - hlock->holdtime_stamp;
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700266
Dave Jonesf82b2172008-08-11 09:30:23 +0200267 stats = get_lock_stats(hlock_class(hlock));
Peter Zijlstraf20786f2007-07-19 01:48:56 -0700268 if (hlock->read)
269 lock_time_inc(&stats->read_holdtime, holdtime);
270 else
271 lock_time_inc(&stats->write_holdtime, holdtime);
272 put_lock_stats(stats);
273}
274#else
275static inline void lock_release_holdtime(struct held_lock *hlock)
276{
277}
278#endif
279
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700280/*
281 * We keep a global list of all lock classes. The list only grows,
282 * never shrinks. The list is only accessed with the lockdep
283 * spinlock lock held.
284 */
285LIST_HEAD(all_lock_classes);
286
287/*
288 * The lockdep classes are in a hash-table as well, for fast lookup:
289 */
290#define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1)
291#define CLASSHASH_SIZE (1UL << CLASSHASH_BITS)
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700292#define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700293#define classhashentry(key) (classhash_table + __classhashfn((key)))
294
295static struct list_head classhash_table[CLASSHASH_SIZE];
296
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700297/*
298 * We put the lock dependency chains into a hash-table as well, to cache
299 * their existence:
300 */
301#define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1)
302#define CHAINHASH_SIZE (1UL << CHAINHASH_BITS)
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700303#define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700304#define chainhashentry(chain) (chainhash_table + __chainhashfn((chain)))
305
306static struct list_head chainhash_table[CHAINHASH_SIZE];
307
308/*
309 * The hash key of the lock dependency chains is a hash itself too:
310 * it's a hash of all locks taken up to that lock, including that lock.
311 * It's a 64-bit hash, because it's important for the keys to be
312 * unique.
313 */
314#define iterate_chain_key(key1, key2) \
Ingo Molnar03cbc352006-09-29 02:01:46 -0700315 (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
316 ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700317 (key2))
318
Steven Rostedt1d09daa2008-05-12 21:20:55 +0200319void lockdep_off(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700320{
321 current->lockdep_recursion++;
322}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700323EXPORT_SYMBOL(lockdep_off);
324
Steven Rostedt1d09daa2008-05-12 21:20:55 +0200325void lockdep_on(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700326{
327 current->lockdep_recursion--;
328}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700329EXPORT_SYMBOL(lockdep_on);
330
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700331/*
332 * Debugging switches:
333 */
334
335#define VERBOSE 0
Ingo Molnar33e94e92006-12-13 00:34:41 -0800336#define VERY_VERBOSE 0
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700337
338#if VERBOSE
339# define HARDIRQ_VERBOSE 1
340# define SOFTIRQ_VERBOSE 1
Nick Piggincf40bd12009-01-21 08:12:39 +0100341# define RECLAIM_VERBOSE 1
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700342#else
343# define HARDIRQ_VERBOSE 0
344# define SOFTIRQ_VERBOSE 0
Nick Piggincf40bd12009-01-21 08:12:39 +0100345# define RECLAIM_VERBOSE 0
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700346#endif
347
Nick Piggincf40bd12009-01-21 08:12:39 +0100348#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700349/*
350 * Quick filtering for interesting events:
351 */
352static int class_filter(struct lock_class *class)
353{
Andi Kleenf9829cc2006-07-10 04:44:01 -0700354#if 0
355 /* Example */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700356 if (class->name_version == 1 &&
Andi Kleenf9829cc2006-07-10 04:44:01 -0700357 !strcmp(class->name, "lockname"))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700358 return 1;
359 if (class->name_version == 1 &&
Andi Kleenf9829cc2006-07-10 04:44:01 -0700360 !strcmp(class->name, "&struct->lockfield"))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700361 return 1;
Andi Kleenf9829cc2006-07-10 04:44:01 -0700362#endif
Ingo Molnara6640892006-12-13 00:34:39 -0800363 /* Filter everything else. 1 would be to allow everything else */
364 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700365}
366#endif
367
368static int verbose(struct lock_class *class)
369{
370#if VERBOSE
371 return class_filter(class);
372#endif
373 return 0;
374}
375
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700376/*
377 * Stack-trace: tightly packed array of stack backtrace
Ingo Molnar74c383f2006-12-13 00:34:43 -0800378 * addresses. Protected by the graph_lock.
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700379 */
380unsigned long nr_stack_trace_entries;
381static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
382
Dave Jones2c522832013-04-25 13:40:02 -0400383static void print_lockdep_off(const char *bug_msg)
384{
385 printk(KERN_DEBUG "%s\n", bug_msg);
386 printk(KERN_DEBUG "turning off the locking correctness validator.\n");
387 printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
388}
389
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700390static int save_trace(struct stack_trace *trace)
391{
392 trace->nr_entries = 0;
393 trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
394 trace->entries = stack_trace + nr_stack_trace_entries;
395
Andi Kleen5a1b3992006-09-26 10:52:34 +0200396 trace->skip = 3;
Andi Kleen5a1b3992006-09-26 10:52:34 +0200397
Christoph Hellwigab1b6f02007-05-08 00:23:29 -0700398 save_stack_trace(trace);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700399
Peter Zijlstra4f84f432009-07-20 15:27:04 +0200400 /*
401 * Some daft arches put -1 at the end to indicate its a full trace.
402 *
403 * <rant> this is buggy anyway, since it takes a whole extra entry so a
404 * complete trace that maxes out the entries provided will be reported
405 * as incomplete, friggin useless </rant>
406 */
Luck, Tonyea5b41f2009-12-09 14:29:36 -0800407 if (trace->nr_entries != 0 &&
408 trace->entries[trace->nr_entries-1] == ULONG_MAX)
Peter Zijlstra4f84f432009-07-20 15:27:04 +0200409 trace->nr_entries--;
410
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700411 trace->max_entries = trace->nr_entries;
412
413 nr_stack_trace_entries += trace->nr_entries;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700414
Peter Zijlstra4f84f432009-07-20 15:27:04 +0200415 if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) {
Ingo Molnar74c383f2006-12-13 00:34:43 -0800416 if (!debug_locks_off_graph_unlock())
417 return 0;
418
Dave Jones2c522832013-04-25 13:40:02 -0400419 print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
Ingo Molnar74c383f2006-12-13 00:34:43 -0800420 dump_stack();
421
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700422 return 0;
423 }
424
425 return 1;
426}
427
428unsigned int nr_hardirq_chains;
429unsigned int nr_softirq_chains;
430unsigned int nr_process_chains;
431unsigned int max_lockdep_depth;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700432
433#ifdef CONFIG_DEBUG_LOCKDEP
434/*
435 * We cannot printk in early bootup code. Not even early_printk()
436 * might work. So we mark any initialization errors and printk
437 * about it later on, in lockdep_info().
438 */
439static int lockdep_init_error;
Ming Lei81140ac2011-11-17 13:34:32 +0800440static const char *lock_init_error;
Johannes Bergc71063c2007-07-19 01:49:02 -0700441static unsigned long lockdep_init_trace_data[20];
442static struct stack_trace lockdep_init_trace = {
443 .max_entries = ARRAY_SIZE(lockdep_init_trace_data),
444 .entries = lockdep_init_trace_data,
445};
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700446
447/*
448 * Various lockdep statistics:
449 */
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200450DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700451#endif
452
453/*
454 * Locking printouts:
455 */
456
Peter Zijlstrafabe9c42009-01-22 14:51:01 +0100457#define __USAGE(__STATE) \
Peter Zijlstrab4b136f2009-01-29 14:50:36 +0100458 [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \
459 [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \
460 [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\
461 [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R",
Peter Zijlstrafabe9c42009-01-22 14:51:01 +0100462
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700463static const char *usage_str[] =
464{
Peter Zijlstrafabe9c42009-01-22 14:51:01 +0100465#define LOCKDEP_STATE(__STATE) __USAGE(__STATE)
466#include "lockdep_states.h"
467#undef LOCKDEP_STATE
468 [LOCK_USED] = "INITIAL USE",
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700469};
470
471const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
472{
Alexey Dobriyanffb45122007-05-08 00:28:41 -0700473 return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700474}
475
Peter Zijlstra3ff176c2009-01-22 17:40:42 +0100476static inline unsigned long lock_flag(enum lock_usage_bit bit)
477{
478 return 1UL << bit;
479}
480
481static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit)
482{
483 char c = '.';
484
485 if (class->usage_mask & lock_flag(bit + 2))
486 c = '+';
487 if (class->usage_mask & lock_flag(bit)) {
488 c = '-';
489 if (class->usage_mask & lock_flag(bit + 2))
490 c = '?';
491 }
492
493 return c;
494}
495
Peter Zijlstraf510b232009-01-22 17:53:47 +0100496void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700497{
Peter Zijlstraf510b232009-01-22 17:53:47 +0100498 int i = 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700499
Peter Zijlstraf510b232009-01-22 17:53:47 +0100500#define LOCKDEP_STATE(__STATE) \
501 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \
502 usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ);
503#include "lockdep_states.h"
504#undef LOCKDEP_STATE
505
506 usage[i] = '\0';
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700507}
508
Steven Rostedte5e78d02011-11-02 20:24:16 -0400509static void __print_lock_name(struct lock_class *class)
Steven Rostedt3003eba2011-04-20 21:41:54 -0400510{
511 char str[KSYM_NAME_LEN];
512 const char *name;
513
514 name = class->name;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700515 if (!name) {
516 name = __get_key_name(class->key, str);
Steven Rostedte5e78d02011-11-02 20:24:16 -0400517 printk("%s", name);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700518 } else {
Steven Rostedte5e78d02011-11-02 20:24:16 -0400519 printk("%s", name);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700520 if (class->name_version > 1)
521 printk("#%d", class->name_version);
522 if (class->subclass)
523 printk("/%d", class->subclass);
524 }
Steven Rostedte5e78d02011-11-02 20:24:16 -0400525}
526
527static void print_lock_name(struct lock_class *class)
528{
529 char usage[LOCK_USAGE_CHARS];
530
531 get_usage_chars(class, usage);
532
533 printk(" (");
534 __print_lock_name(class);
Peter Zijlstraf510b232009-01-22 17:53:47 +0100535 printk("){%s}", usage);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700536}
537
538static void print_lockdep_cache(struct lockdep_map *lock)
539{
540 const char *name;
Tejun Heo9281ace2007-07-17 04:03:51 -0700541 char str[KSYM_NAME_LEN];
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700542
543 name = lock->name;
544 if (!name)
545 name = __get_key_name(lock->key->subkeys, str);
546
547 printk("%s", name);
548}
549
550static void print_lock(struct held_lock *hlock)
551{
Dave Jonesf82b2172008-08-11 09:30:23 +0200552 print_lock_name(hlock_class(hlock));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700553 printk(", at: ");
554 print_ip_sym(hlock->acquire_ip);
555}
556
557static void lockdep_print_held_locks(struct task_struct *curr)
558{
559 int i, depth = curr->lockdep_depth;
560
561 if (!depth) {
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -0700562 printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700563 return;
564 }
565 printk("%d lock%s held by %s/%d:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -0700566 depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700567
568 for (i = 0; i < depth; i++) {
569 printk(" #%d: ", i);
570 print_lock(curr->held_locks + i);
571 }
572}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700573
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +0100574static void print_kernel_ident(void)
Dave Jones99de0552006-09-29 02:00:10 -0700575{
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +0100576 printk("%s %.*s %s\n", init_utsname()->release,
Serge E. Hallyn96b644b2006-10-02 02:18:13 -0700577 (int)strcspn(init_utsname()->version, " "),
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +0100578 init_utsname()->version,
579 print_tainted());
Dave Jones99de0552006-09-29 02:00:10 -0700580}
581
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700582static int very_verbose(struct lock_class *class)
583{
584#if VERY_VERBOSE
585 return class_filter(class);
586#endif
587 return 0;
588}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700589
590/*
591 * Is this the address of a static object:
592 */
Sasha Levin8dce7a92013-06-13 18:41:16 -0400593#ifdef __KERNEL__
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700594static int static_obj(void *obj)
595{
596 unsigned long start = (unsigned long) &_stext,
597 end = (unsigned long) &_end,
598 addr = (unsigned long) obj;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700599
600 /*
601 * static variable?
602 */
603 if ((addr >= start) && (addr < end))
604 return 1;
605
Mike Frysinger2a9ad182009-09-22 16:44:16 -0700606 if (arch_is_kernel_data(addr))
607 return 1;
608
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700609 /*
Tejun Heo10fad5e2010-03-10 18:57:54 +0900610 * in-kernel percpu var?
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700611 */
Tejun Heo10fad5e2010-03-10 18:57:54 +0900612 if (is_kernel_percpu_address(addr))
613 return 1;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700614
615 /*
Tejun Heo10fad5e2010-03-10 18:57:54 +0900616 * module static or percpu var?
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700617 */
Tejun Heo10fad5e2010-03-10 18:57:54 +0900618 return is_module_address(addr) || is_module_percpu_address(addr);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700619}
Sasha Levin8dce7a92013-06-13 18:41:16 -0400620#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700621
622/*
623 * To make lock name printouts unique, we calculate a unique
624 * class->name_version generation counter:
625 */
626static int count_matching_names(struct lock_class *new_class)
627{
628 struct lock_class *class;
629 int count = 0;
630
631 if (!new_class->name)
632 return 0;
633
634 list_for_each_entry(class, &all_lock_classes, lock_entry) {
635 if (new_class->key - new_class->subclass == class->key)
636 return class->name_version;
637 if (class->name && !strcmp(class->name, new_class->name))
638 count = max(count, class->name_version);
639 }
640
641 return count + 1;
642}
643
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700644/*
645 * Register a lock's class in the hash-table, if the class is not present
646 * yet. Otherwise we look it up. We cache the result in the lock object
647 * itself, so actual lookup of the hash should be once per lock object.
648 */
649static inline struct lock_class *
Ingo Molnard6d897c2006-07-10 04:44:04 -0700650look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700651{
652 struct lockdep_subclass_key *key;
653 struct list_head *hash_head;
654 struct lock_class *class;
655
656#ifdef CONFIG_DEBUG_LOCKDEP
657 /*
658 * If the architecture calls into lockdep before initializing
659 * the hashes then we'll warn about it later. (we cannot printk
660 * right now)
661 */
662 if (unlikely(!lockdep_initialized)) {
663 lockdep_init();
664 lockdep_init_error = 1;
Ming Lei81140ac2011-11-17 13:34:32 +0800665 lock_init_error = lock->name;
Johannes Bergc71063c2007-07-19 01:49:02 -0700666 save_stack_trace(&lockdep_init_trace);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700667 }
668#endif
669
Hitoshi Mitake4ba053c2010-10-13 17:30:26 +0900670 if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
671 debug_locks_off();
672 printk(KERN_ERR
673 "BUG: looking up invalid subclass: %u\n", subclass);
674 printk(KERN_ERR
675 "turning off the locking correctness validator.\n");
676 dump_stack();
677 return NULL;
678 }
679
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700680 /*
681 * Static locks do not have their class-keys yet - for them the key
682 * is the lock object itself:
683 */
684 if (unlikely(!lock->key))
685 lock->key = (void *)lock;
686
687 /*
688 * NOTE: the class-key must be unique. For dynamic locks, a static
689 * lock_class_key variable is passed in through the mutex_init()
690 * (or spin_lock_init()) call - which acts as the key. For static
691 * locks we use the lock object itself as the key.
692 */
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700693 BUILD_BUG_ON(sizeof(struct lock_class_key) >
694 sizeof(struct lockdep_map));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700695
696 key = lock->key->subkeys + subclass;
697
698 hash_head = classhashentry(key);
699
700 /*
701 * We can walk the hash lockfree, because the hash only
702 * grows, and we are careful when adding entries to the end:
703 */
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700704 list_for_each_entry(class, hash_head, hash_entry) {
705 if (class->key == key) {
Peter Zijlstra0119fee2011-09-02 01:30:29 +0200706 /*
707 * Huh! same key, different name? Did someone trample
708 * on some memory? We're most confused.
709 */
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700710 WARN_ON_ONCE(class->name != lock->name);
Ingo Molnard6d897c2006-07-10 04:44:04 -0700711 return class;
Peter Zijlstra4b32d0a2007-07-19 01:48:59 -0700712 }
713 }
Ingo Molnard6d897c2006-07-10 04:44:04 -0700714
715 return NULL;
716}
717
718/*
719 * Register a lock's class in the hash-table, if the class is not present
720 * yet. Otherwise we look it up. We cache the result in the lock object
721 * itself, so actual lookup of the hash should be once per lock object.
722 */
723static inline struct lock_class *
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -0400724register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
Ingo Molnard6d897c2006-07-10 04:44:04 -0700725{
726 struct lockdep_subclass_key *key;
727 struct list_head *hash_head;
728 struct lock_class *class;
Ingo Molnar70e45062006-12-06 20:40:50 -0800729 unsigned long flags;
Ingo Molnard6d897c2006-07-10 04:44:04 -0700730
731 class = look_up_lock_class(lock, subclass);
732 if (likely(class))
Yong Zhang87cdee72011-11-09 16:07:14 +0800733 goto out_set_class_cache;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700734
735 /*
736 * Debug-check: all keys must be persistent!
737 */
738 if (!static_obj(lock->key)) {
739 debug_locks_off();
740 printk("INFO: trying to register non-static key.\n");
741 printk("the code is fine but needs lockdep annotation.\n");
742 printk("turning off the locking correctness validator.\n");
743 dump_stack();
744
745 return NULL;
746 }
747
Ingo Molnard6d897c2006-07-10 04:44:04 -0700748 key = lock->key->subkeys + subclass;
749 hash_head = classhashentry(key);
750
Ingo Molnar70e45062006-12-06 20:40:50 -0800751 raw_local_irq_save(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800752 if (!graph_lock()) {
753 raw_local_irq_restore(flags);
754 return NULL;
755 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700756 /*
757 * We have to do the hash-walk again, to avoid races
758 * with another CPU:
759 */
760 list_for_each_entry(class, hash_head, hash_entry)
761 if (class->key == key)
762 goto out_unlock_set;
763 /*
764 * Allocate a new key from the static array, and add it to
765 * the hash:
766 */
767 if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
Ingo Molnar74c383f2006-12-13 00:34:43 -0800768 if (!debug_locks_off_graph_unlock()) {
769 raw_local_irq_restore(flags);
770 return NULL;
771 }
Ingo Molnar70e45062006-12-06 20:40:50 -0800772 raw_local_irq_restore(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800773
Dave Jones2c522832013-04-25 13:40:02 -0400774 print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
Peter Zijlstraeedeeab2009-03-18 12:38:47 +0100775 dump_stack();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700776 return NULL;
777 }
778 class = lock_classes + nr_lock_classes++;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +0200779 debug_atomic_inc(nr_unused_locks);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700780 class->key = key;
781 class->name = lock->name;
782 class->subclass = subclass;
783 INIT_LIST_HEAD(&class->lock_entry);
784 INIT_LIST_HEAD(&class->locks_before);
785 INIT_LIST_HEAD(&class->locks_after);
786 class->name_version = count_matching_names(class);
787 /*
788 * We use RCU's safe list-add method to make
789 * parallel walking of the hash-list safe:
790 */
791 list_add_tail_rcu(&class->hash_entry, hash_head);
Dale Farnsworth14811972008-02-25 23:03:02 +0100792 /*
793 * Add it to the global list of classes:
794 */
795 list_add_tail_rcu(&class->lock_entry, &all_lock_classes);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700796
797 if (verbose(class)) {
Ingo Molnar74c383f2006-12-13 00:34:43 -0800798 graph_unlock();
Ingo Molnar70e45062006-12-06 20:40:50 -0800799 raw_local_irq_restore(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800800
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700801 printk("\nnew class %p: %s", class->key, class->name);
802 if (class->name_version > 1)
803 printk("#%d", class->name_version);
804 printk("\n");
805 dump_stack();
Ingo Molnar74c383f2006-12-13 00:34:43 -0800806
Ingo Molnar70e45062006-12-06 20:40:50 -0800807 raw_local_irq_save(flags);
Ingo Molnar74c383f2006-12-13 00:34:43 -0800808 if (!graph_lock()) {
809 raw_local_irq_restore(flags);
810 return NULL;
811 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700812 }
813out_unlock_set:
Ingo Molnar74c383f2006-12-13 00:34:43 -0800814 graph_unlock();
Ingo Molnar70e45062006-12-06 20:40:50 -0800815 raw_local_irq_restore(flags);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700816
Yong Zhang87cdee72011-11-09 16:07:14 +0800817out_set_class_cache:
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -0400818 if (!subclass || force)
Hitoshi Mitake62016252010-10-05 18:01:51 +0900819 lock->class_cache[0] = class;
820 else if (subclass < NR_LOCKDEP_CACHING_CLASSES)
821 lock->class_cache[subclass] = class;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700822
Peter Zijlstra0119fee2011-09-02 01:30:29 +0200823 /*
824 * Hash collision, did we smoke some? We found a class with a matching
825 * hash but the subclass -- which is hashed in -- didn't match.
826 */
Jarek Poplawski381a2292007-02-10 01:44:58 -0800827 if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
828 return NULL;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700829
830 return class;
831}
832
Peter Zijlstraca58abc2007-07-19 01:48:53 -0700833#ifdef CONFIG_PROVE_LOCKING
Ingo Molnarfbb9ce952006-07-03 00:24:50 -0700834/*
Peter Zijlstra8e182572007-07-19 01:48:54 -0700835 * Allocate a lockdep entry. (assumes the graph_lock held, returns
836 * with NULL on failure)
837 */
838static struct lock_list *alloc_list_entry(void)
839{
840 if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
841 if (!debug_locks_off_graph_unlock())
842 return NULL;
843
Dave Jones2c522832013-04-25 13:40:02 -0400844 print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
Peter Zijlstraeedeeab2009-03-18 12:38:47 +0100845 dump_stack();
Peter Zijlstra8e182572007-07-19 01:48:54 -0700846 return NULL;
847 }
848 return list_entries + nr_list_entries++;
849}
850
851/*
852 * Add a new dependency to the head of the list:
853 */
854static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
Yong Zhang4726f2a2010-05-04 14:16:48 +0800855 struct list_head *head, unsigned long ip,
856 int distance, struct stack_trace *trace)
Peter Zijlstra8e182572007-07-19 01:48:54 -0700857{
858 struct lock_list *entry;
859 /*
860 * Lock not present yet - get a new dependency struct and
861 * add it to the list:
862 */
863 entry = alloc_list_entry();
864 if (!entry)
865 return 0;
866
Zhu Yi74870172008-08-27 14:33:00 +0800867 entry->class = this;
868 entry->distance = distance;
Yong Zhang4726f2a2010-05-04 14:16:48 +0800869 entry->trace = *trace;
Peter Zijlstra8e182572007-07-19 01:48:54 -0700870 /*
871 * Since we never remove from the dependency list, the list can
872 * be walked lockless by other CPUs, it's only allocation
873 * that must be protected by the spinlock. But this also means
874 * we must make new entries visible only once writes to the
875 * entry become visible - hence the RCU op:
876 */
877 list_add_tail_rcu(&entry->entry, head);
878
879 return 1;
880}
881
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200882/*
883 * For good efficiency of modular, we use power of 2
884 */
Peter Zijlstraaf012962009-07-16 15:44:29 +0200885#define MAX_CIRCULAR_QUEUE_SIZE 4096UL
886#define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1)
887
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200888/*
889 * The circular_queue and helpers is used to implement the
Peter Zijlstraaf012962009-07-16 15:44:29 +0200890 * breadth-first search(BFS)algorithem, by which we can build
891 * the shortest path from the next lock to be acquired to the
892 * previous held lock if there is a circular between them.
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200893 */
Peter Zijlstraaf012962009-07-16 15:44:29 +0200894struct circular_queue {
895 unsigned long element[MAX_CIRCULAR_QUEUE_SIZE];
896 unsigned int front, rear;
897};
898
899static struct circular_queue lock_cq;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200900
Ming Lei12f3dfd2009-07-16 15:44:29 +0200901unsigned int max_bfs_queue_depth;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200902
Ming Leie351b662009-07-22 22:48:09 +0800903static unsigned int lockdep_dependency_gen_id;
904
Peter Zijlstraaf012962009-07-16 15:44:29 +0200905static inline void __cq_init(struct circular_queue *cq)
906{
907 cq->front = cq->rear = 0;
Ming Leie351b662009-07-22 22:48:09 +0800908 lockdep_dependency_gen_id++;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200909}
910
911static inline int __cq_empty(struct circular_queue *cq)
912{
913 return (cq->front == cq->rear);
914}
915
916static inline int __cq_full(struct circular_queue *cq)
917{
918 return ((cq->rear + 1) & CQ_MASK) == cq->front;
919}
920
921static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem)
922{
923 if (__cq_full(cq))
924 return -1;
925
926 cq->element[cq->rear] = elem;
927 cq->rear = (cq->rear + 1) & CQ_MASK;
928 return 0;
929}
930
931static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem)
932{
933 if (__cq_empty(cq))
934 return -1;
935
936 *elem = cq->element[cq->front];
937 cq->front = (cq->front + 1) & CQ_MASK;
938 return 0;
939}
940
941static inline unsigned int __cq_get_elem_count(struct circular_queue *cq)
942{
943 return (cq->rear - cq->front) & CQ_MASK;
944}
945
946static inline void mark_lock_accessed(struct lock_list *lock,
947 struct lock_list *parent)
948{
949 unsigned long nr;
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200950
Peter Zijlstraaf012962009-07-16 15:44:29 +0200951 nr = lock - list_entries;
Peter Zijlstra0119fee2011-09-02 01:30:29 +0200952 WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
Peter Zijlstraaf012962009-07-16 15:44:29 +0200953 lock->parent = parent;
Ming Leie351b662009-07-22 22:48:09 +0800954 lock->class->dep_gen_id = lockdep_dependency_gen_id;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200955}
956
957static inline unsigned long lock_accessed(struct lock_list *lock)
958{
959 unsigned long nr;
Peter Zijlstra98c33ed2009-07-21 13:19:07 +0200960
Peter Zijlstraaf012962009-07-16 15:44:29 +0200961 nr = lock - list_entries;
Peter Zijlstra0119fee2011-09-02 01:30:29 +0200962 WARN_ON(nr >= nr_list_entries); /* Out-of-bounds, input fail */
Ming Leie351b662009-07-22 22:48:09 +0800963 return lock->class->dep_gen_id == lockdep_dependency_gen_id;
Peter Zijlstraaf012962009-07-16 15:44:29 +0200964}
965
966static inline struct lock_list *get_lock_parent(struct lock_list *child)
967{
968 return child->parent;
969}
970
971static inline int get_lock_depth(struct lock_list *child)
972{
973 int depth = 0;
974 struct lock_list *parent;
975
976 while ((parent = get_lock_parent(child))) {
977 child = parent;
978 depth++;
979 }
980 return depth;
981}
982
Ming Lei9e2d5512009-07-16 15:44:29 +0200983static int __bfs(struct lock_list *source_entry,
Peter Zijlstraaf012962009-07-16 15:44:29 +0200984 void *data,
985 int (*match)(struct lock_list *entry, void *data),
986 struct lock_list **target_entry,
987 int forward)
Ming Leic94aa5c2009-07-16 15:44:29 +0200988{
989 struct lock_list *entry;
Ming Leid588e462009-07-16 15:44:29 +0200990 struct list_head *head;
Ming Leic94aa5c2009-07-16 15:44:29 +0200991 struct circular_queue *cq = &lock_cq;
992 int ret = 1;
993
Ming Lei9e2d5512009-07-16 15:44:29 +0200994 if (match(source_entry, data)) {
Ming Leic94aa5c2009-07-16 15:44:29 +0200995 *target_entry = source_entry;
996 ret = 0;
997 goto exit;
998 }
999
Ming Leid588e462009-07-16 15:44:29 +02001000 if (forward)
1001 head = &source_entry->class->locks_after;
1002 else
1003 head = &source_entry->class->locks_before;
1004
1005 if (list_empty(head))
1006 goto exit;
1007
1008 __cq_init(cq);
Ming Leic94aa5c2009-07-16 15:44:29 +02001009 __cq_enqueue(cq, (unsigned long)source_entry);
1010
1011 while (!__cq_empty(cq)) {
1012 struct lock_list *lock;
Ming Leic94aa5c2009-07-16 15:44:29 +02001013
1014 __cq_dequeue(cq, (unsigned long *)&lock);
1015
1016 if (!lock->class) {
1017 ret = -2;
1018 goto exit;
1019 }
1020
1021 if (forward)
1022 head = &lock->class->locks_after;
1023 else
1024 head = &lock->class->locks_before;
1025
1026 list_for_each_entry(entry, head, entry) {
1027 if (!lock_accessed(entry)) {
Ming Lei12f3dfd2009-07-16 15:44:29 +02001028 unsigned int cq_depth;
Ming Leic94aa5c2009-07-16 15:44:29 +02001029 mark_lock_accessed(entry, lock);
Ming Lei9e2d5512009-07-16 15:44:29 +02001030 if (match(entry, data)) {
Ming Leic94aa5c2009-07-16 15:44:29 +02001031 *target_entry = entry;
1032 ret = 0;
1033 goto exit;
1034 }
1035
1036 if (__cq_enqueue(cq, (unsigned long)entry)) {
1037 ret = -1;
1038 goto exit;
1039 }
Ming Lei12f3dfd2009-07-16 15:44:29 +02001040 cq_depth = __cq_get_elem_count(cq);
1041 if (max_bfs_queue_depth < cq_depth)
1042 max_bfs_queue_depth = cq_depth;
Ming Leic94aa5c2009-07-16 15:44:29 +02001043 }
1044 }
1045 }
1046exit:
1047 return ret;
1048}
1049
Ming Leid7aaba12009-07-16 15:44:29 +02001050static inline int __bfs_forwards(struct lock_list *src_entry,
Ming Lei9e2d5512009-07-16 15:44:29 +02001051 void *data,
1052 int (*match)(struct lock_list *entry, void *data),
1053 struct lock_list **target_entry)
Ming Leic94aa5c2009-07-16 15:44:29 +02001054{
Ming Lei9e2d5512009-07-16 15:44:29 +02001055 return __bfs(src_entry, data, match, target_entry, 1);
Ming Leic94aa5c2009-07-16 15:44:29 +02001056
1057}
1058
Ming Leid7aaba12009-07-16 15:44:29 +02001059static inline int __bfs_backwards(struct lock_list *src_entry,
Ming Lei9e2d5512009-07-16 15:44:29 +02001060 void *data,
1061 int (*match)(struct lock_list *entry, void *data),
1062 struct lock_list **target_entry)
Ming Leic94aa5c2009-07-16 15:44:29 +02001063{
Ming Lei9e2d5512009-07-16 15:44:29 +02001064 return __bfs(src_entry, data, match, target_entry, 0);
Ming Leic94aa5c2009-07-16 15:44:29 +02001065
1066}
1067
Peter Zijlstra8e182572007-07-19 01:48:54 -07001068/*
1069 * Recursive, forwards-direction lock-dependency checking, used for
1070 * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
1071 * checking.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001072 */
Peter Zijlstra8e182572007-07-19 01:48:54 -07001073
1074/*
1075 * Print a dependency chain entry (this is only done when a deadlock
1076 * has been detected):
1077 */
1078static noinline int
Ming Lei24208ca2009-07-16 15:44:29 +02001079print_circular_bug_entry(struct lock_list *target, int depth)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001080{
1081 if (debug_locks_silent)
1082 return 0;
1083 printk("\n-> #%u", depth);
1084 print_lock_name(target->class);
1085 printk(":\n");
1086 print_stack_trace(&target->trace, 6);
1087
1088 return 0;
1089}
1090
Steven Rostedtf4185812011-04-20 21:41:55 -04001091static void
1092print_circular_lock_scenario(struct held_lock *src,
1093 struct held_lock *tgt,
1094 struct lock_list *prt)
1095{
1096 struct lock_class *source = hlock_class(src);
1097 struct lock_class *target = hlock_class(tgt);
1098 struct lock_class *parent = prt->class;
1099
1100 /*
1101 * A direct locking problem where unsafe_class lock is taken
1102 * directly by safe_class lock, then all we need to show
1103 * is the deadlock scenario, as it is obvious that the
1104 * unsafe lock is taken under the safe lock.
1105 *
1106 * But if there is a chain instead, where the safe lock takes
1107 * an intermediate lock (middle_class) where this lock is
1108 * not the same as the safe lock, then the lock chain is
1109 * used to describe the problem. Otherwise we would need
1110 * to show a different CPU case for each link in the chain
1111 * from the safe_class lock to the unsafe_class lock.
1112 */
1113 if (parent != source) {
1114 printk("Chain exists of:\n ");
1115 __print_lock_name(source);
1116 printk(" --> ");
1117 __print_lock_name(parent);
1118 printk(" --> ");
1119 __print_lock_name(target);
1120 printk("\n\n");
1121 }
1122
1123 printk(" Possible unsafe locking scenario:\n\n");
1124 printk(" CPU0 CPU1\n");
1125 printk(" ---- ----\n");
1126 printk(" lock(");
1127 __print_lock_name(target);
1128 printk(");\n");
1129 printk(" lock(");
1130 __print_lock_name(parent);
1131 printk(");\n");
1132 printk(" lock(");
1133 __print_lock_name(target);
1134 printk(");\n");
1135 printk(" lock(");
1136 __print_lock_name(source);
1137 printk(");\n");
1138 printk("\n *** DEADLOCK ***\n\n");
1139}
1140
Peter Zijlstra8e182572007-07-19 01:48:54 -07001141/*
1142 * When a circular dependency is detected, print the
1143 * header first:
1144 */
1145static noinline int
Ming Leidb0002a2009-07-16 15:44:29 +02001146print_circular_bug_header(struct lock_list *entry, unsigned int depth,
1147 struct held_lock *check_src,
1148 struct held_lock *check_tgt)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001149{
1150 struct task_struct *curr = current;
1151
Ming Leic94aa5c2009-07-16 15:44:29 +02001152 if (debug_locks_silent)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001153 return 0;
1154
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07001155 printk("\n");
1156 printk("======================================================\n");
1157 printk("[ INFO: possible circular locking dependency detected ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01001158 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07001159 printk("-------------------------------------------------------\n");
Peter Zijlstra8e182572007-07-19 01:48:54 -07001160 printk("%s/%d is trying to acquire lock:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001161 curr->comm, task_pid_nr(curr));
Ming Leidb0002a2009-07-16 15:44:29 +02001162 print_lock(check_src);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001163 printk("\nbut task is already holding lock:\n");
Ming Leidb0002a2009-07-16 15:44:29 +02001164 print_lock(check_tgt);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001165 printk("\nwhich lock already depends on the new lock.\n\n");
1166 printk("\nthe existing dependency chain (in reverse order) is:\n");
1167
1168 print_circular_bug_entry(entry, depth);
1169
1170 return 0;
1171}
1172
Ming Lei9e2d5512009-07-16 15:44:29 +02001173static inline int class_equal(struct lock_list *entry, void *data)
1174{
1175 return entry->class == data;
1176}
1177
Ming Leidb0002a2009-07-16 15:44:29 +02001178static noinline int print_circular_bug(struct lock_list *this,
1179 struct lock_list *target,
1180 struct held_lock *check_src,
1181 struct held_lock *check_tgt)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001182{
1183 struct task_struct *curr = current;
Ming Leic94aa5c2009-07-16 15:44:29 +02001184 struct lock_list *parent;
Steven Rostedtf4185812011-04-20 21:41:55 -04001185 struct lock_list *first_parent;
Ming Lei24208ca2009-07-16 15:44:29 +02001186 int depth;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001187
Ming Leic94aa5c2009-07-16 15:44:29 +02001188 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001189 return 0;
1190
Ming Leidb0002a2009-07-16 15:44:29 +02001191 if (!save_trace(&this->trace))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001192 return 0;
1193
Ming Leic94aa5c2009-07-16 15:44:29 +02001194 depth = get_lock_depth(target);
1195
Ming Leidb0002a2009-07-16 15:44:29 +02001196 print_circular_bug_header(target, depth, check_src, check_tgt);
Ming Leic94aa5c2009-07-16 15:44:29 +02001197
1198 parent = get_lock_parent(target);
Steven Rostedtf4185812011-04-20 21:41:55 -04001199 first_parent = parent;
Ming Leic94aa5c2009-07-16 15:44:29 +02001200
1201 while (parent) {
1202 print_circular_bug_entry(parent, --depth);
1203 parent = get_lock_parent(parent);
1204 }
Peter Zijlstra8e182572007-07-19 01:48:54 -07001205
1206 printk("\nother info that might help us debug this:\n\n");
Steven Rostedtf4185812011-04-20 21:41:55 -04001207 print_circular_lock_scenario(check_src, check_tgt,
1208 first_parent);
1209
Peter Zijlstra8e182572007-07-19 01:48:54 -07001210 lockdep_print_held_locks(curr);
1211
1212 printk("\nstack backtrace:\n");
1213 dump_stack();
1214
1215 return 0;
1216}
1217
Ming Leidb0002a2009-07-16 15:44:29 +02001218static noinline int print_bfs_bug(int ret)
1219{
1220 if (!debug_locks_off_graph_unlock())
1221 return 0;
1222
Peter Zijlstra0119fee2011-09-02 01:30:29 +02001223 /*
1224 * Breadth-first-search failed, graph got corrupted?
1225 */
Ming Leidb0002a2009-07-16 15:44:29 +02001226 WARN(1, "lockdep bfs error:%d\n", ret);
1227
1228 return 0;
1229}
1230
Ming Leief681022009-07-16 15:44:29 +02001231static int noop_count(struct lock_list *entry, void *data)
David Miller419ca3f2008-07-29 21:45:03 -07001232{
Ming Leief681022009-07-16 15:44:29 +02001233 (*(unsigned long *)data)++;
1234 return 0;
David Miller419ca3f2008-07-29 21:45:03 -07001235}
1236
Fengguang Wu5216d532013-11-09 00:55:35 +08001237static unsigned long __lockdep_count_forward_deps(struct lock_list *this)
Ming Leief681022009-07-16 15:44:29 +02001238{
1239 unsigned long count = 0;
1240 struct lock_list *uninitialized_var(target_entry);
1241
1242 __bfs_forwards(this, (void *)&count, noop_count, &target_entry);
1243
1244 return count;
1245}
David Miller419ca3f2008-07-29 21:45:03 -07001246unsigned long lockdep_count_forward_deps(struct lock_class *class)
1247{
1248 unsigned long ret, flags;
Ming Leief681022009-07-16 15:44:29 +02001249 struct lock_list this;
1250
1251 this.parent = NULL;
1252 this.class = class;
David Miller419ca3f2008-07-29 21:45:03 -07001253
1254 local_irq_save(flags);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001255 arch_spin_lock(&lockdep_lock);
Ming Leief681022009-07-16 15:44:29 +02001256 ret = __lockdep_count_forward_deps(&this);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001257 arch_spin_unlock(&lockdep_lock);
David Miller419ca3f2008-07-29 21:45:03 -07001258 local_irq_restore(flags);
1259
1260 return ret;
1261}
1262
Fengguang Wu5216d532013-11-09 00:55:35 +08001263static unsigned long __lockdep_count_backward_deps(struct lock_list *this)
David Miller419ca3f2008-07-29 21:45:03 -07001264{
Ming Leief681022009-07-16 15:44:29 +02001265 unsigned long count = 0;
1266 struct lock_list *uninitialized_var(target_entry);
David Miller419ca3f2008-07-29 21:45:03 -07001267
Ming Leief681022009-07-16 15:44:29 +02001268 __bfs_backwards(this, (void *)&count, noop_count, &target_entry);
David Miller419ca3f2008-07-29 21:45:03 -07001269
Ming Leief681022009-07-16 15:44:29 +02001270 return count;
David Miller419ca3f2008-07-29 21:45:03 -07001271}
1272
1273unsigned long lockdep_count_backward_deps(struct lock_class *class)
1274{
1275 unsigned long ret, flags;
Ming Leief681022009-07-16 15:44:29 +02001276 struct lock_list this;
1277
1278 this.parent = NULL;
1279 this.class = class;
David Miller419ca3f2008-07-29 21:45:03 -07001280
1281 local_irq_save(flags);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001282 arch_spin_lock(&lockdep_lock);
Ming Leief681022009-07-16 15:44:29 +02001283 ret = __lockdep_count_backward_deps(&this);
Thomas Gleixner0199c4e2009-12-02 20:01:25 +01001284 arch_spin_unlock(&lockdep_lock);
David Miller419ca3f2008-07-29 21:45:03 -07001285 local_irq_restore(flags);
1286
1287 return ret;
1288}
1289
Peter Zijlstra8e182572007-07-19 01:48:54 -07001290/*
1291 * Prove that the dependency graph starting at <entry> can not
1292 * lead to <target>. Print an error and return 0 if it does.
1293 */
1294static noinline int
Ming Leidb0002a2009-07-16 15:44:29 +02001295check_noncircular(struct lock_list *root, struct lock_class *target,
1296 struct lock_list **target_entry)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001297{
Ming Leidb0002a2009-07-16 15:44:29 +02001298 int result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001299
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001300 debug_atomic_inc(nr_cyclic_checks);
David Miller419ca3f2008-07-29 21:45:03 -07001301
Ming Leid7aaba12009-07-16 15:44:29 +02001302 result = __bfs_forwards(root, target, class_equal, target_entry);
Ming Leidb0002a2009-07-16 15:44:29 +02001303
1304 return result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001305}
1306
Steven Rostedt81d68a92008-05-12 21:20:42 +02001307#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001308/*
1309 * Forwards and backwards subgraph searching, for the purposes of
1310 * proving that two subgraphs can be connected by a new dependency
1311 * without creating any illegal irq-safe -> irq-unsafe lock dependency.
1312 */
Peter Zijlstra8e182572007-07-19 01:48:54 -07001313
Ming Leid7aaba12009-07-16 15:44:29 +02001314static inline int usage_match(struct lock_list *entry, void *bit)
1315{
1316 return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit);
1317}
1318
1319
1320
Peter Zijlstra8e182572007-07-19 01:48:54 -07001321/*
1322 * Find a node in the forwards-direction dependency sub-graph starting
Ming Leid7aaba12009-07-16 15:44:29 +02001323 * at @root->class that matches @bit.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001324 *
Ming Leid7aaba12009-07-16 15:44:29 +02001325 * Return 0 if such a node exists in the subgraph, and put that node
1326 * into *@target_entry.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001327 *
Ming Leid7aaba12009-07-16 15:44:29 +02001328 * Return 1 otherwise and keep *@target_entry unchanged.
1329 * Return <0 on error.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001330 */
Ming Leid7aaba12009-07-16 15:44:29 +02001331static int
1332find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit,
1333 struct lock_list **target_entry)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001334{
Ming Leid7aaba12009-07-16 15:44:29 +02001335 int result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001336
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001337 debug_atomic_inc(nr_find_usage_forwards_checks);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001338
Ming Leid7aaba12009-07-16 15:44:29 +02001339 result = __bfs_forwards(root, (void *)bit, usage_match, target_entry);
1340
1341 return result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001342}
1343
1344/*
1345 * Find a node in the backwards-direction dependency sub-graph starting
Ming Leid7aaba12009-07-16 15:44:29 +02001346 * at @root->class that matches @bit.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001347 *
Ming Leid7aaba12009-07-16 15:44:29 +02001348 * Return 0 if such a node exists in the subgraph, and put that node
1349 * into *@target_entry.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001350 *
Ming Leid7aaba12009-07-16 15:44:29 +02001351 * Return 1 otherwise and keep *@target_entry unchanged.
1352 * Return <0 on error.
Peter Zijlstra8e182572007-07-19 01:48:54 -07001353 */
Ming Leid7aaba12009-07-16 15:44:29 +02001354static int
1355find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
1356 struct lock_list **target_entry)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001357{
Ming Leid7aaba12009-07-16 15:44:29 +02001358 int result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001359
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02001360 debug_atomic_inc(nr_find_usage_backwards_checks);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001361
Ming Leid7aaba12009-07-16 15:44:29 +02001362 result = __bfs_backwards(root, (void *)bit, usage_match, target_entry);
Dave Jonesf82b2172008-08-11 09:30:23 +02001363
Ming Leid7aaba12009-07-16 15:44:29 +02001364 return result;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001365}
1366
Peter Zijlstraaf012962009-07-16 15:44:29 +02001367static void print_lock_class_header(struct lock_class *class, int depth)
1368{
1369 int bit;
1370
1371 printk("%*s->", depth, "");
1372 print_lock_name(class);
1373 printk(" ops: %lu", class->ops);
1374 printk(" {\n");
1375
1376 for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
1377 if (class->usage_mask & (1 << bit)) {
1378 int len = depth;
1379
1380 len += printk("%*s %s", depth, "", usage_str[bit]);
1381 len += printk(" at:\n");
1382 print_stack_trace(class->usage_traces + bit, len);
1383 }
1384 }
1385 printk("%*s }\n", depth, "");
1386
1387 printk("%*s ... key at: ",depth,"");
1388 print_ip_sym((unsigned long)class->key);
1389}
1390
1391/*
1392 * printk the shortest lock dependencies from @start to @end in reverse order:
1393 */
1394static void __used
1395print_shortest_lock_dependencies(struct lock_list *leaf,
1396 struct lock_list *root)
1397{
1398 struct lock_list *entry = leaf;
1399 int depth;
1400
1401 /*compute depth from generated tree by BFS*/
1402 depth = get_lock_depth(leaf);
1403
1404 do {
1405 print_lock_class_header(entry->class, depth);
1406 printk("%*s ... acquired at:\n", depth, "");
1407 print_stack_trace(&entry->trace, 2);
1408 printk("\n");
1409
1410 if (depth == 0 && (entry != root)) {
Steven Rostedt6be8c392011-04-20 21:41:58 -04001411 printk("lockdep:%s bad path found in chain graph\n", __func__);
Peter Zijlstraaf012962009-07-16 15:44:29 +02001412 break;
1413 }
1414
1415 entry = get_lock_parent(entry);
1416 depth--;
1417 } while (entry && (depth >= 0));
1418
1419 return;
1420}
Ming Leid7aaba12009-07-16 15:44:29 +02001421
Steven Rostedt3003eba2011-04-20 21:41:54 -04001422static void
1423print_irq_lock_scenario(struct lock_list *safe_entry,
1424 struct lock_list *unsafe_entry,
Steven Rostedtdad3d742011-04-20 21:41:57 -04001425 struct lock_class *prev_class,
1426 struct lock_class *next_class)
Steven Rostedt3003eba2011-04-20 21:41:54 -04001427{
1428 struct lock_class *safe_class = safe_entry->class;
1429 struct lock_class *unsafe_class = unsafe_entry->class;
Steven Rostedtdad3d742011-04-20 21:41:57 -04001430 struct lock_class *middle_class = prev_class;
Steven Rostedt3003eba2011-04-20 21:41:54 -04001431
1432 if (middle_class == safe_class)
Steven Rostedtdad3d742011-04-20 21:41:57 -04001433 middle_class = next_class;
Steven Rostedt3003eba2011-04-20 21:41:54 -04001434
1435 /*
1436 * A direct locking problem where unsafe_class lock is taken
1437 * directly by safe_class lock, then all we need to show
1438 * is the deadlock scenario, as it is obvious that the
1439 * unsafe lock is taken under the safe lock.
1440 *
1441 * But if there is a chain instead, where the safe lock takes
1442 * an intermediate lock (middle_class) where this lock is
1443 * not the same as the safe lock, then the lock chain is
1444 * used to describe the problem. Otherwise we would need
1445 * to show a different CPU case for each link in the chain
1446 * from the safe_class lock to the unsafe_class lock.
1447 */
1448 if (middle_class != unsafe_class) {
1449 printk("Chain exists of:\n ");
1450 __print_lock_name(safe_class);
1451 printk(" --> ");
1452 __print_lock_name(middle_class);
1453 printk(" --> ");
1454 __print_lock_name(unsafe_class);
1455 printk("\n\n");
1456 }
1457
1458 printk(" Possible interrupt unsafe locking scenario:\n\n");
1459 printk(" CPU0 CPU1\n");
1460 printk(" ---- ----\n");
1461 printk(" lock(");
1462 __print_lock_name(unsafe_class);
1463 printk(");\n");
1464 printk(" local_irq_disable();\n");
1465 printk(" lock(");
1466 __print_lock_name(safe_class);
1467 printk(");\n");
1468 printk(" lock(");
1469 __print_lock_name(middle_class);
1470 printk(");\n");
1471 printk(" <Interrupt>\n");
1472 printk(" lock(");
1473 __print_lock_name(safe_class);
1474 printk(");\n");
1475 printk("\n *** DEADLOCK ***\n\n");
1476}
1477
Peter Zijlstra8e182572007-07-19 01:48:54 -07001478static int
1479print_bad_irq_dependency(struct task_struct *curr,
Ming Lei24208ca2009-07-16 15:44:29 +02001480 struct lock_list *prev_root,
1481 struct lock_list *next_root,
1482 struct lock_list *backwards_entry,
1483 struct lock_list *forwards_entry,
Peter Zijlstra8e182572007-07-19 01:48:54 -07001484 struct held_lock *prev,
1485 struct held_lock *next,
1486 enum lock_usage_bit bit1,
1487 enum lock_usage_bit bit2,
1488 const char *irqclass)
1489{
1490 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1491 return 0;
1492
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07001493 printk("\n");
1494 printk("======================================================\n");
1495 printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
Peter Zijlstra8e182572007-07-19 01:48:54 -07001496 irqclass, irqclass);
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01001497 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07001498 printk("------------------------------------------------------\n");
Peter Zijlstra8e182572007-07-19 01:48:54 -07001499 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 -07001500 curr->comm, task_pid_nr(curr),
Peter Zijlstra8e182572007-07-19 01:48:54 -07001501 curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
1502 curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
1503 curr->hardirqs_enabled,
1504 curr->softirqs_enabled);
1505 print_lock(next);
1506
1507 printk("\nand this task is already holding:\n");
1508 print_lock(prev);
1509 printk("which would create a new lock dependency:\n");
Dave Jonesf82b2172008-08-11 09:30:23 +02001510 print_lock_name(hlock_class(prev));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001511 printk(" ->");
Dave Jonesf82b2172008-08-11 09:30:23 +02001512 print_lock_name(hlock_class(next));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001513 printk("\n");
1514
1515 printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
1516 irqclass);
Ming Lei24208ca2009-07-16 15:44:29 +02001517 print_lock_name(backwards_entry->class);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001518 printk("\n... which became %s-irq-safe at:\n", irqclass);
1519
Ming Lei24208ca2009-07-16 15:44:29 +02001520 print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001521
1522 printk("\nto a %s-irq-unsafe lock:\n", irqclass);
Ming Lei24208ca2009-07-16 15:44:29 +02001523 print_lock_name(forwards_entry->class);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001524 printk("\n... which became %s-irq-unsafe at:\n", irqclass);
1525 printk("...");
1526
Ming Lei24208ca2009-07-16 15:44:29 +02001527 print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001528
1529 printk("\nother info that might help us debug this:\n\n");
Steven Rostedtdad3d742011-04-20 21:41:57 -04001530 print_irq_lock_scenario(backwards_entry, forwards_entry,
1531 hlock_class(prev), hlock_class(next));
Steven Rostedt3003eba2011-04-20 21:41:54 -04001532
Peter Zijlstra8e182572007-07-19 01:48:54 -07001533 lockdep_print_held_locks(curr);
1534
Ming Lei24208ca2009-07-16 15:44:29 +02001535 printk("\nthe dependencies between %s-irq-safe lock", irqclass);
1536 printk(" and the holding lock:\n");
1537 if (!save_trace(&prev_root->trace))
1538 return 0;
1539 print_shortest_lock_dependencies(backwards_entry, prev_root);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001540
Ming Lei24208ca2009-07-16 15:44:29 +02001541 printk("\nthe dependencies between the lock to be acquired");
1542 printk(" and %s-irq-unsafe lock:\n", irqclass);
1543 if (!save_trace(&next_root->trace))
1544 return 0;
1545 print_shortest_lock_dependencies(forwards_entry, next_root);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001546
1547 printk("\nstack backtrace:\n");
1548 dump_stack();
1549
1550 return 0;
1551}
1552
1553static int
1554check_usage(struct task_struct *curr, struct held_lock *prev,
1555 struct held_lock *next, enum lock_usage_bit bit_backwards,
1556 enum lock_usage_bit bit_forwards, const char *irqclass)
1557{
1558 int ret;
Ming Lei24208ca2009-07-16 15:44:29 +02001559 struct lock_list this, that;
Ming Leid7aaba12009-07-16 15:44:29 +02001560 struct lock_list *uninitialized_var(target_entry);
Ming Lei24208ca2009-07-16 15:44:29 +02001561 struct lock_list *uninitialized_var(target_entry1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001562
Ming Leid7aaba12009-07-16 15:44:29 +02001563 this.parent = NULL;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001564
Ming Leid7aaba12009-07-16 15:44:29 +02001565 this.class = hlock_class(prev);
1566 ret = find_usage_backwards(&this, bit_backwards, &target_entry);
Peter Zijlstraaf012962009-07-16 15:44:29 +02001567 if (ret < 0)
1568 return print_bfs_bug(ret);
1569 if (ret == 1)
1570 return ret;
Ming Leid7aaba12009-07-16 15:44:29 +02001571
Ming Lei24208ca2009-07-16 15:44:29 +02001572 that.parent = NULL;
1573 that.class = hlock_class(next);
1574 ret = find_usage_forwards(&that, bit_forwards, &target_entry1);
Peter Zijlstraaf012962009-07-16 15:44:29 +02001575 if (ret < 0)
1576 return print_bfs_bug(ret);
1577 if (ret == 1)
1578 return ret;
Ming Leid7aaba12009-07-16 15:44:29 +02001579
Ming Lei24208ca2009-07-16 15:44:29 +02001580 return print_bad_irq_dependency(curr, &this, &that,
1581 target_entry, target_entry1,
1582 prev, next,
Peter Zijlstra8e182572007-07-19 01:48:54 -07001583 bit_backwards, bit_forwards, irqclass);
1584}
1585
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001586static const char *state_names[] = {
1587#define LOCKDEP_STATE(__STATE) \
Peter Zijlstrab4b136f2009-01-29 14:50:36 +01001588 __stringify(__STATE),
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001589#include "lockdep_states.h"
1590#undef LOCKDEP_STATE
1591};
1592
1593static const char *state_rnames[] = {
1594#define LOCKDEP_STATE(__STATE) \
Peter Zijlstrab4b136f2009-01-29 14:50:36 +01001595 __stringify(__STATE)"-READ",
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001596#include "lockdep_states.h"
1597#undef LOCKDEP_STATE
1598};
1599
1600static inline const char *state_name(enum lock_usage_bit bit)
1601{
1602 return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2];
1603}
1604
1605static int exclusive_bit(int new_bit)
1606{
1607 /*
1608 * USED_IN
1609 * USED_IN_READ
1610 * ENABLED
1611 * ENABLED_READ
1612 *
1613 * bit 0 - write/read
1614 * bit 1 - used_in/enabled
1615 * bit 2+ state
1616 */
1617
1618 int state = new_bit & ~3;
1619 int dir = new_bit & 2;
1620
1621 /*
1622 * keep state, bit flip the direction and strip read.
1623 */
1624 return state | (dir ^ 2);
1625}
1626
1627static int check_irq_usage(struct task_struct *curr, struct held_lock *prev,
1628 struct held_lock *next, enum lock_usage_bit bit)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001629{
1630 /*
1631 * Prove that the new dependency does not connect a hardirq-safe
1632 * lock with a hardirq-unsafe lock - to achieve this we search
1633 * the backwards-subgraph starting at <prev>, and the
1634 * forwards-subgraph starting at <next>:
1635 */
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001636 if (!check_usage(curr, prev, next, bit,
1637 exclusive_bit(bit), state_name(bit)))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001638 return 0;
1639
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001640 bit++; /* _READ */
1641
Peter Zijlstra8e182572007-07-19 01:48:54 -07001642 /*
1643 * Prove that the new dependency does not connect a hardirq-safe-read
1644 * lock with a hardirq-unsafe lock - to achieve this we search
1645 * the backwards-subgraph starting at <prev>, and the
1646 * forwards-subgraph starting at <next>:
1647 */
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001648 if (!check_usage(curr, prev, next, bit,
1649 exclusive_bit(bit), state_name(bit)))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001650 return 0;
1651
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001652 return 1;
1653}
Peter Zijlstra8e182572007-07-19 01:48:54 -07001654
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001655static int
1656check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1657 struct held_lock *next)
1658{
1659#define LOCKDEP_STATE(__STATE) \
1660 if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \
Nick Piggincf40bd12009-01-21 08:12:39 +01001661 return 0;
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01001662#include "lockdep_states.h"
1663#undef LOCKDEP_STATE
Nick Piggincf40bd12009-01-21 08:12:39 +01001664
Peter Zijlstra8e182572007-07-19 01:48:54 -07001665 return 1;
1666}
1667
1668static void inc_chains(void)
1669{
1670 if (current->hardirq_context)
1671 nr_hardirq_chains++;
1672 else {
1673 if (current->softirq_context)
1674 nr_softirq_chains++;
1675 else
1676 nr_process_chains++;
1677 }
1678}
1679
1680#else
1681
1682static inline int
1683check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
1684 struct held_lock *next)
1685{
1686 return 1;
1687}
1688
1689static inline void inc_chains(void)
1690{
1691 nr_process_chains++;
1692}
1693
1694#endif
1695
Steven Rostedt48702ec2011-04-20 21:41:56 -04001696static void
1697print_deadlock_scenario(struct held_lock *nxt,
1698 struct held_lock *prv)
1699{
1700 struct lock_class *next = hlock_class(nxt);
1701 struct lock_class *prev = hlock_class(prv);
1702
1703 printk(" Possible unsafe locking scenario:\n\n");
1704 printk(" CPU0\n");
1705 printk(" ----\n");
1706 printk(" lock(");
1707 __print_lock_name(prev);
1708 printk(");\n");
1709 printk(" lock(");
1710 __print_lock_name(next);
1711 printk(");\n");
1712 printk("\n *** DEADLOCK ***\n\n");
1713 printk(" May be due to missing lock nesting notation\n\n");
1714}
1715
Peter Zijlstra8e182572007-07-19 01:48:54 -07001716static int
1717print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
1718 struct held_lock *next)
1719{
1720 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
1721 return 0;
1722
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07001723 printk("\n");
1724 printk("=============================================\n");
1725 printk("[ INFO: possible recursive locking detected ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01001726 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07001727 printk("---------------------------------------------\n");
Peter Zijlstra8e182572007-07-19 01:48:54 -07001728 printk("%s/%d is trying to acquire lock:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07001729 curr->comm, task_pid_nr(curr));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001730 print_lock(next);
1731 printk("\nbut task is already holding lock:\n");
1732 print_lock(prev);
1733
1734 printk("\nother info that might help us debug this:\n");
Steven Rostedt48702ec2011-04-20 21:41:56 -04001735 print_deadlock_scenario(next, prev);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001736 lockdep_print_held_locks(curr);
1737
1738 printk("\nstack backtrace:\n");
1739 dump_stack();
1740
1741 return 0;
1742}
1743
1744/*
1745 * Check whether we are holding such a class already.
1746 *
1747 * (Note that this has to be done separately, because the graph cannot
1748 * detect such classes of deadlocks.)
1749 *
1750 * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
1751 */
1752static int
1753check_deadlock(struct task_struct *curr, struct held_lock *next,
1754 struct lockdep_map *next_instance, int read)
1755{
1756 struct held_lock *prev;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001757 struct held_lock *nest = NULL;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001758 int i;
1759
1760 for (i = 0; i < curr->lockdep_depth; i++) {
1761 prev = curr->held_locks + i;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001762
1763 if (prev->instance == next->nest_lock)
1764 nest = prev;
1765
Dave Jonesf82b2172008-08-11 09:30:23 +02001766 if (hlock_class(prev) != hlock_class(next))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001767 continue;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001768
Peter Zijlstra8e182572007-07-19 01:48:54 -07001769 /*
1770 * Allow read-after-read recursion of the same
1771 * lock class (i.e. read_lock(lock)+read_lock(lock)):
1772 */
1773 if ((read == 2) && prev->read)
1774 return 2;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02001775
1776 /*
1777 * We're holding the nest_lock, which serializes this lock's
1778 * nesting behaviour.
1779 */
1780 if (nest)
1781 return 2;
1782
Peter Zijlstra8e182572007-07-19 01:48:54 -07001783 return print_deadlock_bug(curr, prev, next);
1784 }
1785 return 1;
1786}
1787
1788/*
1789 * There was a chain-cache miss, and we are about to add a new dependency
1790 * to a previous lock. We recursively validate the following rules:
1791 *
1792 * - would the adding of the <prev> -> <next> dependency create a
1793 * circular dependency in the graph? [== circular deadlock]
1794 *
1795 * - does the new prev->next dependency connect any hardirq-safe lock
1796 * (in the full backwards-subgraph starting at <prev>) with any
1797 * hardirq-unsafe lock (in the full forwards-subgraph starting at
1798 * <next>)? [== illegal lock inversion with hardirq contexts]
1799 *
1800 * - does the new prev->next dependency connect any softirq-safe lock
1801 * (in the full backwards-subgraph starting at <prev>) with any
1802 * softirq-unsafe lock (in the full forwards-subgraph starting at
1803 * <next>)? [== illegal lock inversion with softirq contexts]
1804 *
1805 * any of these scenarios could lead to a deadlock.
1806 *
1807 * Then if all the validations pass, we add the forwards and backwards
1808 * dependency.
1809 */
1810static int
1811check_prev_add(struct task_struct *curr, struct held_lock *prev,
Yong Zhang4726f2a2010-05-04 14:16:48 +08001812 struct held_lock *next, int distance, int trylock_loop)
Peter Zijlstra8e182572007-07-19 01:48:54 -07001813{
1814 struct lock_list *entry;
1815 int ret;
Ming Leidb0002a2009-07-16 15:44:29 +02001816 struct lock_list this;
1817 struct lock_list *uninitialized_var(target_entry);
Yong Zhang4726f2a2010-05-04 14:16:48 +08001818 /*
1819 * Static variable, serialized by the graph_lock().
1820 *
1821 * We use this static variable to save the stack trace in case
1822 * we call into this function multiple times due to encountering
1823 * trylocks in the held lock stack.
1824 */
1825 static struct stack_trace trace;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001826
1827 /*
1828 * Prove that the new <prev> -> <next> dependency would not
1829 * create a circular dependency in the graph. (We do this by
1830 * forward-recursing into the graph starting at <next>, and
1831 * checking whether we can reach <prev>.)
1832 *
1833 * We are using global variables to control the recursion, to
1834 * keep the stackframe size of the recursive functions low:
1835 */
Ming Leidb0002a2009-07-16 15:44:29 +02001836 this.class = hlock_class(next);
1837 this.parent = NULL;
1838 ret = check_noncircular(&this, hlock_class(prev), &target_entry);
1839 if (unlikely(!ret))
1840 return print_circular_bug(&this, target_entry, next, prev);
1841 else if (unlikely(ret < 0))
1842 return print_bfs_bug(ret);
Ming Leic94aa5c2009-07-16 15:44:29 +02001843
Peter Zijlstra8e182572007-07-19 01:48:54 -07001844 if (!check_prev_add_irq(curr, prev, next))
1845 return 0;
1846
1847 /*
1848 * For recursive read-locks we do all the dependency checks,
1849 * but we dont store read-triggered dependencies (only
1850 * write-triggered dependencies). This ensures that only the
1851 * write-side dependencies matter, and that if for example a
1852 * write-lock never takes any other locks, then the reads are
1853 * equivalent to a NOP.
1854 */
1855 if (next->read == 2 || prev->read == 2)
1856 return 1;
1857 /*
1858 * Is the <prev> -> <next> dependency already present?
1859 *
1860 * (this may occur even though this is a new chain: consider
1861 * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
1862 * chains - the second one will be new, but L1 already has
1863 * L2 added to its dependency list, due to the first chain.)
1864 */
Dave Jonesf82b2172008-08-11 09:30:23 +02001865 list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) {
1866 if (entry->class == hlock_class(next)) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07001867 if (distance == 1)
1868 entry->distance = 1;
1869 return 2;
1870 }
1871 }
1872
Yong Zhang4726f2a2010-05-04 14:16:48 +08001873 if (!trylock_loop && !save_trace(&trace))
1874 return 0;
1875
Peter Zijlstra8e182572007-07-19 01:48:54 -07001876 /*
1877 * Ok, all validations passed, add the new lock
1878 * to the previous lock's dependency list:
1879 */
Dave Jonesf82b2172008-08-11 09:30:23 +02001880 ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
1881 &hlock_class(prev)->locks_after,
Yong Zhang4726f2a2010-05-04 14:16:48 +08001882 next->acquire_ip, distance, &trace);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001883
1884 if (!ret)
1885 return 0;
1886
Dave Jonesf82b2172008-08-11 09:30:23 +02001887 ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
1888 &hlock_class(next)->locks_before,
Yong Zhang4726f2a2010-05-04 14:16:48 +08001889 next->acquire_ip, distance, &trace);
Peter Zijlstra8e182572007-07-19 01:48:54 -07001890 if (!ret)
1891 return 0;
1892
1893 /*
1894 * Debugging printouts:
1895 */
Dave Jonesf82b2172008-08-11 09:30:23 +02001896 if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07001897 graph_unlock();
1898 printk("\n new dependency: ");
Dave Jonesf82b2172008-08-11 09:30:23 +02001899 print_lock_name(hlock_class(prev));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001900 printk(" => ");
Dave Jonesf82b2172008-08-11 09:30:23 +02001901 print_lock_name(hlock_class(next));
Peter Zijlstra8e182572007-07-19 01:48:54 -07001902 printk("\n");
1903 dump_stack();
1904 return graph_lock();
1905 }
1906 return 1;
1907}
1908
1909/*
1910 * Add the dependency to all directly-previous locks that are 'relevant'.
1911 * The ones that are relevant are (in increasing distance from curr):
1912 * all consecutive trylock entries and the final non-trylock entry - or
1913 * the end of this context's lock-chain - whichever comes first.
1914 */
1915static int
1916check_prevs_add(struct task_struct *curr, struct held_lock *next)
1917{
1918 int depth = curr->lockdep_depth;
Yong Zhang4726f2a2010-05-04 14:16:48 +08001919 int trylock_loop = 0;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001920 struct held_lock *hlock;
1921
1922 /*
1923 * Debugging checks.
1924 *
1925 * Depth must not be zero for a non-head lock:
1926 */
1927 if (!depth)
1928 goto out_bug;
1929 /*
1930 * At least two relevant locks must exist for this
1931 * to be a head:
1932 */
1933 if (curr->held_locks[depth].irq_context !=
1934 curr->held_locks[depth-1].irq_context)
1935 goto out_bug;
1936
1937 for (;;) {
1938 int distance = curr->lockdep_depth - depth + 1;
1939 hlock = curr->held_locks + depth-1;
1940 /*
1941 * Only non-recursive-read entries get new dependencies
1942 * added:
1943 */
1944 if (hlock->read != 2) {
Yong Zhang4726f2a2010-05-04 14:16:48 +08001945 if (!check_prev_add(curr, hlock, next,
1946 distance, trylock_loop))
Peter Zijlstra8e182572007-07-19 01:48:54 -07001947 return 0;
1948 /*
1949 * Stop after the first non-trylock entry,
1950 * as non-trylock entries have added their
1951 * own direct dependencies already, so this
1952 * lock is connected to them indirectly:
1953 */
1954 if (!hlock->trylock)
1955 break;
1956 }
1957 depth--;
1958 /*
1959 * End of lock-stack?
1960 */
1961 if (!depth)
1962 break;
1963 /*
1964 * Stop the search if we cross into another context:
1965 */
1966 if (curr->held_locks[depth].irq_context !=
1967 curr->held_locks[depth-1].irq_context)
1968 break;
Yong Zhang4726f2a2010-05-04 14:16:48 +08001969 trylock_loop = 1;
Peter Zijlstra8e182572007-07-19 01:48:54 -07001970 }
1971 return 1;
1972out_bug:
1973 if (!debug_locks_off_graph_unlock())
1974 return 0;
1975
Peter Zijlstra0119fee2011-09-02 01:30:29 +02001976 /*
1977 * Clearly we all shouldn't be here, but since we made it we
1978 * can reliable say we messed up our state. See the above two
1979 * gotos for reasons why we could possibly end up here.
1980 */
Peter Zijlstra8e182572007-07-19 01:48:54 -07001981 WARN_ON(1);
1982
1983 return 0;
1984}
1985
1986unsigned long nr_lock_chains;
Huang, Ying443cd502008-06-20 16:39:21 +08001987struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
Huang, Yingcd1a28e2008-06-23 11:20:54 +08001988int nr_chain_hlocks;
Huang, Ying443cd502008-06-20 16:39:21 +08001989static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS];
1990
1991struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i)
1992{
1993 return lock_classes + chain_hlocks[chain->base + i];
1994}
Peter Zijlstra8e182572007-07-19 01:48:54 -07001995
1996/*
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07001997 * Look up a dependency chain. If the key is not present yet then
Jarek Poplawski9e860d02007-05-08 00:30:12 -07001998 * add it and return 1 - in this case the new dependency chain is
1999 * validated. If the key is already hashed, return 0.
2000 * (On return with 1 graph_lock is held.)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002001 */
Huang, Ying443cd502008-06-20 16:39:21 +08002002static inline int lookup_chain_cache(struct task_struct *curr,
2003 struct held_lock *hlock,
2004 u64 chain_key)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002005{
Dave Jonesf82b2172008-08-11 09:30:23 +02002006 struct lock_class *class = hlock_class(hlock);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002007 struct list_head *hash_head = chainhashentry(chain_key);
2008 struct lock_chain *chain;
Hong Zhiguobfaf4af2013-04-04 15:01:21 +08002009 struct held_lock *hlock_curr;
Steven Rostedte0944ee2011-04-20 21:42:00 -04002010 int i, j;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002011
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002012 /*
2013 * We might need to take the graph lock, ensure we've got IRQs
2014 * disabled to make this an IRQ-safe lock.. for recursion reasons
2015 * lockdep won't complain about its own locking errors.
2016 */
Jarek Poplawski381a2292007-02-10 01:44:58 -08002017 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2018 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002019 /*
2020 * We can walk it lock-free, because entries only get added
2021 * to the hash:
2022 */
2023 list_for_each_entry(chain, hash_head, entry) {
2024 if (chain->chain_key == chain_key) {
2025cache_hit:
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002026 debug_atomic_inc(chain_lookup_hits);
Ingo Molnar81fc6852006-12-13 00:34:40 -08002027 if (very_verbose(class))
Andrew Morton755cd902006-12-29 16:49:14 -08002028 printk("\nhash chain already cached, key: "
2029 "%016Lx tail class: [%p] %s\n",
2030 (unsigned long long)chain_key,
2031 class->key, class->name);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002032 return 0;
2033 }
2034 }
Ingo Molnar81fc6852006-12-13 00:34:40 -08002035 if (very_verbose(class))
Andrew Morton755cd902006-12-29 16:49:14 -08002036 printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
2037 (unsigned long long)chain_key, class->key, class->name);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002038 /*
2039 * Allocate a new chain entry from the static array, and add
2040 * it to the hash:
2041 */
Ingo Molnar74c383f2006-12-13 00:34:43 -08002042 if (!graph_lock())
2043 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002044 /*
2045 * We have to walk the chain again locked - to avoid duplicates:
2046 */
2047 list_for_each_entry(chain, hash_head, entry) {
2048 if (chain->chain_key == chain_key) {
Ingo Molnar74c383f2006-12-13 00:34:43 -08002049 graph_unlock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002050 goto cache_hit;
2051 }
2052 }
2053 if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
Ingo Molnar74c383f2006-12-13 00:34:43 -08002054 if (!debug_locks_off_graph_unlock())
2055 return 0;
2056
Dave Jones2c522832013-04-25 13:40:02 -04002057 print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
Peter Zijlstraeedeeab2009-03-18 12:38:47 +01002058 dump_stack();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002059 return 0;
2060 }
2061 chain = lock_chains + nr_lock_chains++;
2062 chain->chain_key = chain_key;
Huang, Ying443cd502008-06-20 16:39:21 +08002063 chain->irq_context = hlock->irq_context;
2064 /* Find the first held_lock of current chain */
Huang, Ying443cd502008-06-20 16:39:21 +08002065 for (i = curr->lockdep_depth - 1; i >= 0; i--) {
2066 hlock_curr = curr->held_locks + i;
Hong Zhiguobfaf4af2013-04-04 15:01:21 +08002067 if (hlock_curr->irq_context != hlock->irq_context)
Huang, Ying443cd502008-06-20 16:39:21 +08002068 break;
Huang, Ying443cd502008-06-20 16:39:21 +08002069 }
2070 i++;
2071 chain->depth = curr->lockdep_depth + 1 - i;
Steven Rostedte0944ee2011-04-20 21:42:00 -04002072 if (likely(nr_chain_hlocks + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) {
2073 chain->base = nr_chain_hlocks;
2074 nr_chain_hlocks += chain->depth;
Huang, Ying443cd502008-06-20 16:39:21 +08002075 for (j = 0; j < chain->depth - 1; j++, i++) {
Dave Jonesf82b2172008-08-11 09:30:23 +02002076 int lock_id = curr->held_locks[i].class_idx - 1;
Huang, Ying443cd502008-06-20 16:39:21 +08002077 chain_hlocks[chain->base + j] = lock_id;
2078 }
2079 chain_hlocks[chain->base + j] = class - lock_classes;
2080 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002081 list_add_tail_rcu(&chain->entry, hash_head);
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002082 debug_atomic_inc(chain_lookup_misses);
Peter Zijlstra8e182572007-07-19 01:48:54 -07002083 inc_chains();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002084
2085 return 1;
2086}
Peter Zijlstra8e182572007-07-19 01:48:54 -07002087
2088static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
Johannes Berg4e6045f2007-10-18 23:39:55 -07002089 struct held_lock *hlock, int chain_head, u64 chain_key)
Peter Zijlstra8e182572007-07-19 01:48:54 -07002090{
2091 /*
2092 * Trylock needs to maintain the stack of held locks, but it
2093 * does not add new dependencies, because trylock can be done
2094 * in any order.
2095 *
2096 * We look up the chain_key and do the O(N^2) check and update of
2097 * the dependencies only if this is a new dependency chain.
2098 * (If lookup_chain_cache() returns with 1 it acquires
2099 * graph_lock for us)
2100 */
2101 if (!hlock->trylock && (hlock->check == 2) &&
Huang, Ying443cd502008-06-20 16:39:21 +08002102 lookup_chain_cache(curr, hlock, chain_key)) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07002103 /*
2104 * Check whether last held lock:
2105 *
2106 * - is irq-safe, if this lock is irq-unsafe
2107 * - is softirq-safe, if this lock is hardirq-unsafe
2108 *
2109 * And check whether the new lock's dependency graph
2110 * could lead back to the previous lock.
2111 *
2112 * any of these scenarios could lead to a deadlock. If
2113 * All validations
2114 */
2115 int ret = check_deadlock(curr, hlock, lock, hlock->read);
2116
2117 if (!ret)
2118 return 0;
2119 /*
2120 * Mark recursive read, as we jump over it when
2121 * building dependencies (just like we jump over
2122 * trylock entries):
2123 */
2124 if (ret == 2)
2125 hlock->read = 2;
2126 /*
2127 * Add dependency only if this lock is not the head
2128 * of the chain, and if it's not a secondary read-lock:
2129 */
2130 if (!chain_head && ret != 2)
2131 if (!check_prevs_add(curr, hlock))
2132 return 0;
2133 graph_unlock();
2134 } else
2135 /* after lookup_chain_cache(): */
2136 if (unlikely(!debug_locks))
2137 return 0;
2138
2139 return 1;
2140}
2141#else
2142static inline int validate_chain(struct task_struct *curr,
2143 struct lockdep_map *lock, struct held_lock *hlock,
Gregory Haskins3aa416b2007-10-11 22:11:11 +02002144 int chain_head, u64 chain_key)
Peter Zijlstra8e182572007-07-19 01:48:54 -07002145{
2146 return 1;
2147}
Peter Zijlstraca58abc2007-07-19 01:48:53 -07002148#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002149
2150/*
2151 * We are building curr_chain_key incrementally, so double-check
2152 * it from scratch, to make sure that it's done correctly:
2153 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002154static void check_chain_key(struct task_struct *curr)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002155{
2156#ifdef CONFIG_DEBUG_LOCKDEP
2157 struct held_lock *hlock, *prev_hlock = NULL;
2158 unsigned int i, id;
2159 u64 chain_key = 0;
2160
2161 for (i = 0; i < curr->lockdep_depth; i++) {
2162 hlock = curr->held_locks + i;
2163 if (chain_key != hlock->prev_chain_key) {
2164 debug_locks_off();
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002165 /*
2166 * We got mighty confused, our chain keys don't match
2167 * with what we expect, someone trample on our task state?
2168 */
Arjan van de Ven2df8b1d2008-07-30 12:43:11 -07002169 WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n",
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002170 curr->lockdep_depth, i,
2171 (unsigned long long)chain_key,
2172 (unsigned long long)hlock->prev_chain_key);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002173 return;
2174 }
Dave Jonesf82b2172008-08-11 09:30:23 +02002175 id = hlock->class_idx - 1;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002176 /*
2177 * Whoops ran out of static storage again?
2178 */
Jarek Poplawski381a2292007-02-10 01:44:58 -08002179 if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
2180 return;
2181
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002182 if (prev_hlock && (prev_hlock->irq_context !=
2183 hlock->irq_context))
2184 chain_key = 0;
2185 chain_key = iterate_chain_key(chain_key, id);
2186 prev_hlock = hlock;
2187 }
2188 if (chain_key != curr->curr_chain_key) {
2189 debug_locks_off();
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002190 /*
2191 * More smoking hash instead of calculating it, damn see these
2192 * numbers float.. I bet that a pink elephant stepped on my memory.
2193 */
Arjan van de Ven2df8b1d2008-07-30 12:43:11 -07002194 WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n",
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002195 curr->lockdep_depth, i,
2196 (unsigned long long)chain_key,
2197 (unsigned long long)curr->curr_chain_key);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002198 }
2199#endif
2200}
2201
Steven Rostedt282b5c22011-04-20 21:41:59 -04002202static void
2203print_usage_bug_scenario(struct held_lock *lock)
2204{
2205 struct lock_class *class = hlock_class(lock);
2206
2207 printk(" Possible unsafe locking scenario:\n\n");
2208 printk(" CPU0\n");
2209 printk(" ----\n");
2210 printk(" lock(");
2211 __print_lock_name(class);
2212 printk(");\n");
2213 printk(" <Interrupt>\n");
2214 printk(" lock(");
2215 __print_lock_name(class);
2216 printk(");\n");
2217 printk("\n *** DEADLOCK ***\n\n");
2218}
2219
Peter Zijlstra8e182572007-07-19 01:48:54 -07002220static int
2221print_usage_bug(struct task_struct *curr, struct held_lock *this,
2222 enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
2223{
2224 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
2225 return 0;
2226
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07002227 printk("\n");
2228 printk("=================================\n");
2229 printk("[ INFO: inconsistent lock state ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01002230 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07002231 printk("---------------------------------\n");
Peter Zijlstra8e182572007-07-19 01:48:54 -07002232
2233 printk("inconsistent {%s} -> {%s} usage.\n",
2234 usage_str[prev_bit], usage_str[new_bit]);
2235
2236 printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07002237 curr->comm, task_pid_nr(curr),
Peter Zijlstra8e182572007-07-19 01:48:54 -07002238 trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
2239 trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
2240 trace_hardirqs_enabled(curr),
2241 trace_softirqs_enabled(curr));
2242 print_lock(this);
2243
2244 printk("{%s} state was registered at:\n", usage_str[prev_bit]);
Dave Jonesf82b2172008-08-11 09:30:23 +02002245 print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
Peter Zijlstra8e182572007-07-19 01:48:54 -07002246
2247 print_irqtrace_events(curr);
2248 printk("\nother info that might help us debug this:\n");
Steven Rostedt282b5c22011-04-20 21:41:59 -04002249 print_usage_bug_scenario(this);
2250
Peter Zijlstra8e182572007-07-19 01:48:54 -07002251 lockdep_print_held_locks(curr);
2252
2253 printk("\nstack backtrace:\n");
2254 dump_stack();
2255
2256 return 0;
2257}
2258
2259/*
2260 * Print out an error if an invalid bit is set:
2261 */
2262static inline int
2263valid_state(struct task_struct *curr, struct held_lock *this,
2264 enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
2265{
Dave Jonesf82b2172008-08-11 09:30:23 +02002266 if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit)))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002267 return print_usage_bug(curr, this, bad_bit, new_bit);
2268 return 1;
2269}
2270
2271static int mark_lock(struct task_struct *curr, struct held_lock *this,
2272 enum lock_usage_bit new_bit);
2273
Steven Rostedt81d68a92008-05-12 21:20:42 +02002274#if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002275
2276/*
2277 * print irq inversion bug:
2278 */
2279static int
Ming Lei24208ca2009-07-16 15:44:29 +02002280print_irq_inversion_bug(struct task_struct *curr,
2281 struct lock_list *root, struct lock_list *other,
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002282 struct held_lock *this, int forwards,
2283 const char *irqclass)
2284{
Steven Rostedtdad3d742011-04-20 21:41:57 -04002285 struct lock_list *entry = other;
2286 struct lock_list *middle = NULL;
2287 int depth;
2288
Ingo Molnar74c383f2006-12-13 00:34:43 -08002289 if (!debug_locks_off_graph_unlock() || debug_locks_silent)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002290 return 0;
2291
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07002292 printk("\n");
2293 printk("=========================================================\n");
2294 printk("[ INFO: possible irq lock inversion dependency detected ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01002295 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07002296 printk("---------------------------------------------------------\n");
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002297 printk("%s/%d just changed the state of lock:\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07002298 curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002299 print_lock(this);
2300 if (forwards)
Peter Zijlstra26575e22009-03-04 14:53:24 +01002301 printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002302 else
Peter Zijlstra26575e22009-03-04 14:53:24 +01002303 printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
Ming Lei24208ca2009-07-16 15:44:29 +02002304 print_lock_name(other->class);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002305 printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
2306
2307 printk("\nother info that might help us debug this:\n");
Steven Rostedtdad3d742011-04-20 21:41:57 -04002308
2309 /* Find a middle lock (if one exists) */
2310 depth = get_lock_depth(other);
2311 do {
2312 if (depth == 0 && (entry != root)) {
2313 printk("lockdep:%s bad path found in chain graph\n", __func__);
2314 break;
2315 }
2316 middle = entry;
2317 entry = get_lock_parent(entry);
2318 depth--;
2319 } while (entry && entry != root && (depth >= 0));
2320 if (forwards)
2321 print_irq_lock_scenario(root, other,
2322 middle ? middle->class : root->class, other->class);
2323 else
2324 print_irq_lock_scenario(other, root,
2325 middle ? middle->class : other->class, root->class);
2326
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002327 lockdep_print_held_locks(curr);
2328
Ming Lei24208ca2009-07-16 15:44:29 +02002329 printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
2330 if (!save_trace(&root->trace))
2331 return 0;
2332 print_shortest_lock_dependencies(other, root);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002333
2334 printk("\nstack backtrace:\n");
2335 dump_stack();
2336
2337 return 0;
2338}
2339
2340/*
2341 * Prove that in the forwards-direction subgraph starting at <this>
2342 * there is no lock matching <mask>:
2343 */
2344static int
2345check_usage_forwards(struct task_struct *curr, struct held_lock *this,
2346 enum lock_usage_bit bit, const char *irqclass)
2347{
2348 int ret;
Ming Leid7aaba12009-07-16 15:44:29 +02002349 struct lock_list root;
2350 struct lock_list *uninitialized_var(target_entry);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002351
Ming Leid7aaba12009-07-16 15:44:29 +02002352 root.parent = NULL;
2353 root.class = hlock_class(this);
2354 ret = find_usage_forwards(&root, bit, &target_entry);
Peter Zijlstraaf012962009-07-16 15:44:29 +02002355 if (ret < 0)
2356 return print_bfs_bug(ret);
2357 if (ret == 1)
2358 return ret;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002359
Ming Lei24208ca2009-07-16 15:44:29 +02002360 return print_irq_inversion_bug(curr, &root, target_entry,
Ming Leid7aaba12009-07-16 15:44:29 +02002361 this, 1, irqclass);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002362}
2363
2364/*
2365 * Prove that in the backwards-direction subgraph starting at <this>
2366 * there is no lock matching <mask>:
2367 */
2368static int
2369check_usage_backwards(struct task_struct *curr, struct held_lock *this,
2370 enum lock_usage_bit bit, const char *irqclass)
2371{
2372 int ret;
Ming Leid7aaba12009-07-16 15:44:29 +02002373 struct lock_list root;
2374 struct lock_list *uninitialized_var(target_entry);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002375
Ming Leid7aaba12009-07-16 15:44:29 +02002376 root.parent = NULL;
2377 root.class = hlock_class(this);
2378 ret = find_usage_backwards(&root, bit, &target_entry);
Peter Zijlstraaf012962009-07-16 15:44:29 +02002379 if (ret < 0)
2380 return print_bfs_bug(ret);
2381 if (ret == 1)
2382 return ret;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002383
Ming Lei24208ca2009-07-16 15:44:29 +02002384 return print_irq_inversion_bug(curr, &root, target_entry,
Oleg Nesterov48d50672010-01-26 19:16:41 +01002385 this, 0, irqclass);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002386}
2387
Ingo Molnar3117df02006-12-13 00:34:43 -08002388void print_irqtrace_events(struct task_struct *curr)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002389{
2390 printk("irq event stamp: %u\n", curr->irq_events);
2391 printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
2392 print_ip_sym(curr->hardirq_enable_ip);
2393 printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
2394 print_ip_sym(curr->hardirq_disable_ip);
2395 printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
2396 print_ip_sym(curr->softirq_enable_ip);
2397 printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
2398 print_ip_sym(curr->softirq_disable_ip);
2399}
2400
Peter Zijlstracd953022009-01-22 16:38:21 +01002401static int HARDIRQ_verbose(struct lock_class *class)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002402{
Peter Zijlstra8e182572007-07-19 01:48:54 -07002403#if HARDIRQ_VERBOSE
2404 return class_filter(class);
2405#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002406 return 0;
2407}
2408
Peter Zijlstracd953022009-01-22 16:38:21 +01002409static int SOFTIRQ_verbose(struct lock_class *class)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002410{
Peter Zijlstra8e182572007-07-19 01:48:54 -07002411#if SOFTIRQ_VERBOSE
2412 return class_filter(class);
2413#endif
2414 return 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002415}
2416
Peter Zijlstracd953022009-01-22 16:38:21 +01002417static int RECLAIM_FS_verbose(struct lock_class *class)
Nick Piggincf40bd12009-01-21 08:12:39 +01002418{
2419#if RECLAIM_VERBOSE
2420 return class_filter(class);
2421#endif
2422 return 0;
2423}
2424
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002425#define STRICT_READ_CHECKS 1
2426
Peter Zijlstracd953022009-01-22 16:38:21 +01002427static int (*state_verbose_f[])(struct lock_class *class) = {
2428#define LOCKDEP_STATE(__STATE) \
2429 __STATE##_verbose,
2430#include "lockdep_states.h"
2431#undef LOCKDEP_STATE
2432};
2433
2434static inline int state_verbose(enum lock_usage_bit bit,
2435 struct lock_class *class)
2436{
2437 return state_verbose_f[bit >> 2](class);
2438}
2439
Peter Zijlstra42c50d52009-01-22 16:58:16 +01002440typedef int (*check_usage_f)(struct task_struct *, struct held_lock *,
2441 enum lock_usage_bit bit, const char *name);
2442
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002443static int
Peter Zijlstra1c21f142009-03-04 13:51:13 +01002444mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2445 enum lock_usage_bit new_bit)
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002446{
Peter Zijlstraf9892092009-01-22 16:09:59 +01002447 int excl_bit = exclusive_bit(new_bit);
Peter Zijlstra9d3651a2009-01-22 17:18:32 +01002448 int read = new_bit & 1;
Peter Zijlstra42c50d52009-01-22 16:58:16 +01002449 int dir = new_bit & 2;
2450
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002451 /*
2452 * mark USED_IN has to look forwards -- to ensure no dependency
2453 * has ENABLED state, which would allow recursion deadlocks.
2454 *
2455 * mark ENABLED has to look backwards -- to ensure no dependee
2456 * has USED_IN state, which, again, would allow recursion deadlocks.
2457 */
Peter Zijlstra42c50d52009-01-22 16:58:16 +01002458 check_usage_f usage = dir ?
2459 check_usage_backwards : check_usage_forwards;
Peter Zijlstraf9892092009-01-22 16:09:59 +01002460
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002461 /*
2462 * Validate that this particular lock does not have conflicting
2463 * usage states.
2464 */
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002465 if (!valid_state(curr, this, new_bit, excl_bit))
2466 return 0;
Peter Zijlstra9d3651a2009-01-22 17:18:32 +01002467
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002468 /*
2469 * Validate that the lock dependencies don't have conflicting usage
2470 * states.
2471 */
2472 if ((!read || !dir || STRICT_READ_CHECKS) &&
Peter Zijlstra1c21f142009-03-04 13:51:13 +01002473 !usage(curr, this, excl_bit, state_name(new_bit & ~1)))
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002474 return 0;
Peter Zijlstra780e8202009-01-22 16:51:29 +01002475
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002476 /*
2477 * Check for read in write conflicts
2478 */
2479 if (!read) {
2480 if (!valid_state(curr, this, new_bit, excl_bit + 1))
2481 return 0;
2482
2483 if (STRICT_READ_CHECKS &&
Peter Zijlstra4f367d8a2009-01-22 18:10:42 +01002484 !usage(curr, this, excl_bit + 1,
2485 state_name(new_bit + 1)))
Peter Zijlstra38aa2712009-01-27 14:53:50 +01002486 return 0;
2487 }
Peter Zijlstra780e8202009-01-22 16:51:29 +01002488
Peter Zijlstracd953022009-01-22 16:38:21 +01002489 if (state_verbose(new_bit, hlock_class(this)))
Peter Zijlstra6a6904d2009-01-22 16:07:44 +01002490 return 2;
2491
2492 return 1;
2493}
2494
Nick Piggincf40bd12009-01-21 08:12:39 +01002495enum mark_type {
Peter Zijlstra36bfb9b2009-01-22 14:12:41 +01002496#define LOCKDEP_STATE(__STATE) __STATE,
2497#include "lockdep_states.h"
2498#undef LOCKDEP_STATE
Nick Piggincf40bd12009-01-21 08:12:39 +01002499};
2500
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002501/*
2502 * Mark all held locks with a usage bit:
2503 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002504static int
Nick Piggincf40bd12009-01-21 08:12:39 +01002505mark_held_locks(struct task_struct *curr, enum mark_type mark)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002506{
2507 enum lock_usage_bit usage_bit;
2508 struct held_lock *hlock;
2509 int i;
2510
2511 for (i = 0; i < curr->lockdep_depth; i++) {
2512 hlock = curr->held_locks + i;
2513
Peter Zijlstracf2ad4d2009-01-27 13:58:08 +01002514 usage_bit = 2 + (mark << 2); /* ENABLED */
2515 if (hlock->read)
2516 usage_bit += 1; /* READ */
2517
2518 BUG_ON(usage_bit >= LOCK_USAGE_STATES);
Nick Piggincf40bd12009-01-21 08:12:39 +01002519
Peter Zijlstra70a06862011-07-25 12:09:59 +02002520 if (hlock_class(hlock)->key == __lockdep_no_validate__.subkeys)
Peter Zijlstraefbe2ee2011-07-07 11:39:45 +02002521 continue;
2522
Jarek Poplawski4ff773bb2007-05-08 00:31:00 -07002523 if (!mark_lock(curr, hlock, usage_bit))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002524 return 0;
2525 }
2526
2527 return 1;
2528}
2529
2530/*
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002531 * Hardirqs will be enabled:
2532 */
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002533static void __trace_hardirqs_on_caller(unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002534{
2535 struct task_struct *curr = current;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002536
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002537 /* we'll do an OFF -> ON transition: */
2538 curr->hardirqs_enabled = 1;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002539
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002540 /*
2541 * We are going to turn hardirqs on, so set the
2542 * usage bit for all held locks:
2543 */
Nick Piggincf40bd12009-01-21 08:12:39 +01002544 if (!mark_held_locks(curr, HARDIRQ))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002545 return;
2546 /*
2547 * If we have softirqs enabled, then set the usage
2548 * bit for all held locks. (disabled hardirqs prevented
2549 * this bit from being set before)
2550 */
2551 if (curr->softirqs_enabled)
Nick Piggincf40bd12009-01-21 08:12:39 +01002552 if (!mark_held_locks(curr, SOFTIRQ))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002553 return;
2554
2555 curr->hardirq_enable_ip = ip;
2556 curr->hardirq_enable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002557 debug_atomic_inc(hardirqs_on_events);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002558}
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002559
Andi Kleenb35f8302014-02-08 08:52:02 +01002560__visible void trace_hardirqs_on_caller(unsigned long ip)
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002561{
2562 time_hardirqs_on(CALLER_ADDR0, ip);
2563
2564 if (unlikely(!debug_locks || current->lockdep_recursion))
2565 return;
2566
Peter Zijlstra7d36b262011-07-26 13:13:44 +02002567 if (unlikely(current->hardirqs_enabled)) {
2568 /*
2569 * Neither irq nor preemption are disabled here
2570 * so this is racy by nature but losing one hit
2571 * in a stat is not a big deal.
2572 */
2573 __debug_atomic_inc(redundant_hardirqs_on);
2574 return;
2575 }
2576
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002577 /*
2578 * We're enabling irqs and according to our state above irqs weren't
2579 * already enabled, yet we find the hardware thinks they are in fact
2580 * enabled.. someone messed up their IRQ state tracing.
2581 */
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002582 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2583 return;
2584
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002585 /*
2586 * See the fine text that goes along with this variable definition.
2587 */
Peter Zijlstra7d36b262011-07-26 13:13:44 +02002588 if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled)))
2589 return;
2590
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002591 /*
2592 * Can't allow enabling interrupts while in an interrupt handler,
2593 * that's general bad form and such. Recursion, limited stack etc..
2594 */
Peter Zijlstra7d36b262011-07-26 13:13:44 +02002595 if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
2596 return;
2597
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002598 current->lockdep_recursion = 1;
2599 __trace_hardirqs_on_caller(ip);
2600 current->lockdep_recursion = 0;
2601}
Steven Rostedt81d68a92008-05-12 21:20:42 +02002602EXPORT_SYMBOL(trace_hardirqs_on_caller);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002603
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002604void trace_hardirqs_on(void)
Steven Rostedt81d68a92008-05-12 21:20:42 +02002605{
2606 trace_hardirqs_on_caller(CALLER_ADDR0);
2607}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002608EXPORT_SYMBOL(trace_hardirqs_on);
2609
2610/*
2611 * Hardirqs were disabled:
2612 */
Andi Kleenb35f8302014-02-08 08:52:02 +01002613__visible void trace_hardirqs_off_caller(unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002614{
2615 struct task_struct *curr = current;
2616
Heiko Carstens6afe40b2008-10-28 11:14:58 +01002617 time_hardirqs_off(CALLER_ADDR0, ip);
Steven Rostedt81d68a92008-05-12 21:20:42 +02002618
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002619 if (unlikely(!debug_locks || current->lockdep_recursion))
2620 return;
2621
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002622 /*
2623 * So we're supposed to get called after you mask local IRQs, but for
2624 * some reason the hardware doesn't quite think you did a proper job.
2625 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002626 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2627 return;
2628
2629 if (curr->hardirqs_enabled) {
2630 /*
2631 * We have done an ON -> OFF transition:
2632 */
2633 curr->hardirqs_enabled = 0;
Heiko Carstens6afe40b2008-10-28 11:14:58 +01002634 curr->hardirq_disable_ip = ip;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002635 curr->hardirq_disable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002636 debug_atomic_inc(hardirqs_off_events);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002637 } else
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002638 debug_atomic_inc(redundant_hardirqs_off);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002639}
Steven Rostedt81d68a92008-05-12 21:20:42 +02002640EXPORT_SYMBOL(trace_hardirqs_off_caller);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002641
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002642void trace_hardirqs_off(void)
Steven Rostedt81d68a92008-05-12 21:20:42 +02002643{
2644 trace_hardirqs_off_caller(CALLER_ADDR0);
2645}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002646EXPORT_SYMBOL(trace_hardirqs_off);
2647
2648/*
2649 * Softirqs will be enabled:
2650 */
2651void trace_softirqs_on(unsigned long ip)
2652{
2653 struct task_struct *curr = current;
2654
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002655 if (unlikely(!debug_locks || current->lockdep_recursion))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002656 return;
2657
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002658 /*
2659 * We fancy IRQs being disabled here, see softirq.c, avoids
2660 * funny state and nesting things.
2661 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002662 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2663 return;
2664
2665 if (curr->softirqs_enabled) {
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002666 debug_atomic_inc(redundant_softirqs_on);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002667 return;
2668 }
2669
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002670 current->lockdep_recursion = 1;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002671 /*
2672 * We'll do an OFF -> ON transition:
2673 */
2674 curr->softirqs_enabled = 1;
2675 curr->softirq_enable_ip = ip;
2676 curr->softirq_enable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002677 debug_atomic_inc(softirqs_on_events);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002678 /*
2679 * We are going to turn softirqs on, so set the
2680 * usage bit for all held locks, if hardirqs are
2681 * enabled too:
2682 */
2683 if (curr->hardirqs_enabled)
Nick Piggincf40bd12009-01-21 08:12:39 +01002684 mark_held_locks(curr, SOFTIRQ);
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002685 current->lockdep_recursion = 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002686}
2687
2688/*
2689 * Softirqs were disabled:
2690 */
2691void trace_softirqs_off(unsigned long ip)
2692{
2693 struct task_struct *curr = current;
2694
Peter Zijlstradd4e5d32011-06-21 17:17:27 +02002695 if (unlikely(!debug_locks || current->lockdep_recursion))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002696 return;
2697
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002698 /*
2699 * We fancy IRQs being disabled here, see softirq.c
2700 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002701 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
2702 return;
2703
2704 if (curr->softirqs_enabled) {
2705 /*
2706 * We have done an ON -> OFF transition:
2707 */
2708 curr->softirqs_enabled = 0;
2709 curr->softirq_disable_ip = ip;
2710 curr->softirq_disable_event = ++curr->irq_events;
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002711 debug_atomic_inc(softirqs_off_events);
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002712 /*
2713 * Whoops, we wanted softirqs off, so why aren't they?
2714 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002715 DEBUG_LOCKS_WARN_ON(!softirq_count());
2716 } else
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002717 debug_atomic_inc(redundant_softirqs_off);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002718}
2719
Peter Zijlstra2f850182009-03-20 11:13:20 +01002720static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags)
Nick Piggincf40bd12009-01-21 08:12:39 +01002721{
2722 struct task_struct *curr = current;
2723
2724 if (unlikely(!debug_locks))
2725 return;
2726
2727 /* no reclaim without waiting on it */
2728 if (!(gfp_mask & __GFP_WAIT))
2729 return;
2730
2731 /* this guy won't enter reclaim */
2732 if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC))
2733 return;
2734
2735 /* We're only interested __GFP_FS allocations for now */
2736 if (!(gfp_mask & __GFP_FS))
2737 return;
2738
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002739 /*
2740 * Oi! Can't be having __GFP_FS allocations with IRQs disabled.
2741 */
Peter Zijlstra2f850182009-03-20 11:13:20 +01002742 if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)))
Nick Piggincf40bd12009-01-21 08:12:39 +01002743 return;
2744
2745 mark_held_locks(curr, RECLAIM_FS);
2746}
2747
Peter Zijlstra2f850182009-03-20 11:13:20 +01002748static void check_flags(unsigned long flags);
2749
2750void lockdep_trace_alloc(gfp_t gfp_mask)
2751{
2752 unsigned long flags;
2753
2754 if (unlikely(current->lockdep_recursion))
2755 return;
2756
2757 raw_local_irq_save(flags);
2758 check_flags(flags);
2759 current->lockdep_recursion = 1;
2760 __lockdep_trace_alloc(gfp_mask, flags);
2761 current->lockdep_recursion = 0;
2762 raw_local_irq_restore(flags);
2763}
2764
Peter Zijlstra8e182572007-07-19 01:48:54 -07002765static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
2766{
2767 /*
2768 * If non-trylock use in a hardirq or softirq context, then
2769 * mark the lock as used in these contexts:
2770 */
2771 if (!hlock->trylock) {
2772 if (hlock->read) {
2773 if (curr->hardirq_context)
2774 if (!mark_lock(curr, hlock,
2775 LOCK_USED_IN_HARDIRQ_READ))
2776 return 0;
2777 if (curr->softirq_context)
2778 if (!mark_lock(curr, hlock,
2779 LOCK_USED_IN_SOFTIRQ_READ))
2780 return 0;
2781 } else {
2782 if (curr->hardirq_context)
2783 if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
2784 return 0;
2785 if (curr->softirq_context)
2786 if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
2787 return 0;
2788 }
2789 }
2790 if (!hlock->hardirqs_off) {
2791 if (hlock->read) {
2792 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002793 LOCK_ENABLED_HARDIRQ_READ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002794 return 0;
2795 if (curr->softirqs_enabled)
2796 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002797 LOCK_ENABLED_SOFTIRQ_READ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002798 return 0;
2799 } else {
2800 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002801 LOCK_ENABLED_HARDIRQ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002802 return 0;
2803 if (curr->softirqs_enabled)
2804 if (!mark_lock(curr, hlock,
Peter Zijlstra4fc95e82009-01-22 13:10:52 +01002805 LOCK_ENABLED_SOFTIRQ))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002806 return 0;
2807 }
2808 }
2809
Nick Piggincf40bd12009-01-21 08:12:39 +01002810 /*
2811 * We reuse the irq context infrastructure more broadly as a general
2812 * context checking code. This tests GFP_FS recursion (a lock taken
2813 * during reclaim for a GFP_FS allocation is held over a GFP_FS
2814 * allocation).
2815 */
2816 if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) {
2817 if (hlock->read) {
2818 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ))
2819 return 0;
2820 } else {
2821 if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS))
2822 return 0;
2823 }
2824 }
2825
Peter Zijlstra8e182572007-07-19 01:48:54 -07002826 return 1;
2827}
2828
2829static int separate_irq_context(struct task_struct *curr,
2830 struct held_lock *hlock)
2831{
2832 unsigned int depth = curr->lockdep_depth;
2833
2834 /*
2835 * Keep track of points where we cross into an interrupt context:
2836 */
2837 hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
2838 curr->softirq_context;
2839 if (depth) {
2840 struct held_lock *prev_hlock;
2841
2842 prev_hlock = curr->held_locks + depth-1;
2843 /*
2844 * If we cross into another context, reset the
2845 * hash key (this also prevents the checking and the
2846 * adding of the dependency to 'prev'):
2847 */
2848 if (prev_hlock->irq_context != hlock->irq_context)
2849 return 1;
2850 }
2851 return 0;
2852}
2853
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002854#else /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
Peter Zijlstra8e182572007-07-19 01:48:54 -07002855
2856static inline
2857int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
2858 enum lock_usage_bit new_bit)
2859{
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002860 WARN_ON(1); /* Impossible innit? when we don't have TRACE_IRQFLAG */
Peter Zijlstra8e182572007-07-19 01:48:54 -07002861 return 1;
2862}
2863
2864static inline int mark_irqflags(struct task_struct *curr,
2865 struct held_lock *hlock)
2866{
2867 return 1;
2868}
2869
2870static inline int separate_irq_context(struct task_struct *curr,
2871 struct held_lock *hlock)
2872{
2873 return 0;
2874}
2875
Peter Zijlstra868a23a2009-02-15 00:25:21 +01002876void lockdep_trace_alloc(gfp_t gfp_mask)
2877{
2878}
2879
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002880#endif /* defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002881
2882/*
Peter Zijlstra8e182572007-07-19 01:48:54 -07002883 * Mark a lock with a usage bit, and validate the state transition:
2884 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02002885static int mark_lock(struct task_struct *curr, struct held_lock *this,
Steven Rostedt0764d232008-05-12 21:20:44 +02002886 enum lock_usage_bit new_bit)
Peter Zijlstra8e182572007-07-19 01:48:54 -07002887{
2888 unsigned int new_mask = 1 << new_bit, ret = 1;
2889
2890 /*
2891 * If already set then do not dirty the cacheline,
2892 * nor do any checks:
2893 */
Dave Jonesf82b2172008-08-11 09:30:23 +02002894 if (likely(hlock_class(this)->usage_mask & new_mask))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002895 return 1;
2896
2897 if (!graph_lock())
2898 return 0;
2899 /*
Lucas De Marchi25985ed2011-03-30 22:57:33 -03002900 * Make sure we didn't race:
Peter Zijlstra8e182572007-07-19 01:48:54 -07002901 */
Dave Jonesf82b2172008-08-11 09:30:23 +02002902 if (unlikely(hlock_class(this)->usage_mask & new_mask)) {
Peter Zijlstra8e182572007-07-19 01:48:54 -07002903 graph_unlock();
2904 return 1;
2905 }
2906
Dave Jonesf82b2172008-08-11 09:30:23 +02002907 hlock_class(this)->usage_mask |= new_mask;
Peter Zijlstra8e182572007-07-19 01:48:54 -07002908
Dave Jonesf82b2172008-08-11 09:30:23 +02002909 if (!save_trace(hlock_class(this)->usage_traces + new_bit))
Peter Zijlstra8e182572007-07-19 01:48:54 -07002910 return 0;
2911
2912 switch (new_bit) {
Peter Zijlstra53464172009-01-22 14:15:53 +01002913#define LOCKDEP_STATE(__STATE) \
2914 case LOCK_USED_IN_##__STATE: \
2915 case LOCK_USED_IN_##__STATE##_READ: \
2916 case LOCK_ENABLED_##__STATE: \
2917 case LOCK_ENABLED_##__STATE##_READ:
2918#include "lockdep_states.h"
2919#undef LOCKDEP_STATE
Peter Zijlstra8e182572007-07-19 01:48:54 -07002920 ret = mark_lock_irq(curr, this, new_bit);
2921 if (!ret)
2922 return 0;
2923 break;
2924 case LOCK_USED:
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02002925 debug_atomic_dec(nr_unused_locks);
Peter Zijlstra8e182572007-07-19 01:48:54 -07002926 break;
2927 default:
2928 if (!debug_locks_off_graph_unlock())
2929 return 0;
2930 WARN_ON(1);
2931 return 0;
2932 }
2933
2934 graph_unlock();
2935
2936 /*
2937 * We must printk outside of the graph_lock:
2938 */
2939 if (ret == 2) {
2940 printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
2941 print_lock(this);
2942 print_irqtrace_events(curr);
2943 dump_stack();
2944 }
2945
2946 return ret;
2947}
2948
2949/*
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002950 * Initialize a lock instance's lock-class mapping info:
2951 */
2952void lockdep_init_map(struct lockdep_map *lock, const char *name,
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -04002953 struct lock_class_key *key, int subclass)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002954{
Yong Zhangd3d03d42011-11-09 16:04:51 +08002955 int i;
2956
2957 kmemcheck_mark_initialized(lock, sizeof(*lock));
2958
2959 for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++)
2960 lock->class_cache[i] = NULL;
Hitoshi Mitake62016252010-10-05 18:01:51 +09002961
Peter Zijlstrac8a25002009-04-17 09:40:49 +02002962#ifdef CONFIG_LOCK_STAT
2963 lock->cpu = raw_smp_processor_id();
2964#endif
2965
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002966 /*
2967 * Can't be having no nameless bastards around this place!
2968 */
Peter Zijlstrac8a25002009-04-17 09:40:49 +02002969 if (DEBUG_LOCKS_WARN_ON(!name)) {
2970 lock->name = "NULL";
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002971 return;
Peter Zijlstrac8a25002009-04-17 09:40:49 +02002972 }
2973
2974 lock->name = name;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002975
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002976 /*
2977 * No key, no joy, we need to hash something.
2978 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002979 if (DEBUG_LOCKS_WARN_ON(!key))
2980 return;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002981 /*
2982 * Sanity check, the lock-class key must be persistent:
2983 */
2984 if (!static_obj(key)) {
2985 printk("BUG: key %p not in .data!\n", key);
Peter Zijlstra0119fee2011-09-02 01:30:29 +02002986 /*
2987 * What it says above ^^^^^, I suggest you read it.
2988 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002989 DEBUG_LOCKS_WARN_ON(1);
2990 return;
2991 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002992 lock->key = key;
Peter Zijlstrac8a25002009-04-17 09:40:49 +02002993
2994 if (unlikely(!debug_locks))
2995 return;
2996
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -04002997 if (subclass)
2998 register_lock_class(lock, subclass, 1);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07002999}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003000EXPORT_SYMBOL_GPL(lockdep_init_map);
3001
Peter Zijlstra1704f472010-03-19 01:37:42 +01003002struct lock_class_key __lockdep_no_validate__;
Kent Overstreetea6749c2012-12-27 22:21:58 -08003003EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
Peter Zijlstra1704f472010-03-19 01:37:42 +01003004
Maarten Lankhorstd0945952012-09-13 11:39:51 +02003005static int
3006print_lock_nested_lock_not_held(struct task_struct *curr,
3007 struct held_lock *hlock,
3008 unsigned long ip)
3009{
3010 if (!debug_locks_off())
3011 return 0;
3012 if (debug_locks_silent)
3013 return 0;
3014
3015 printk("\n");
3016 printk("==================================\n");
3017 printk("[ BUG: Nested lock was not taken ]\n");
3018 print_kernel_ident();
3019 printk("----------------------------------\n");
3020
3021 printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
3022 print_lock(hlock);
3023
3024 printk("\nbut this task is not holding:\n");
3025 printk("%s\n", hlock->nest_lock->name);
3026
3027 printk("\nstack backtrace:\n");
3028 dump_stack();
3029
3030 printk("\nother info that might help us debug this:\n");
3031 lockdep_print_held_locks(curr);
3032
3033 printk("\nstack backtrace:\n");
3034 dump_stack();
3035
3036 return 0;
3037}
3038
3039static int __lock_is_held(struct lockdep_map *lock);
3040
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003041/*
3042 * This gets called for every mutex_lock*()/spin_lock*() operation.
3043 * We maintain the dependency maps and validate the locking attempt:
3044 */
3045static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
3046 int trylock, int read, int check, int hardirqs_off,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003047 struct lockdep_map *nest_lock, unsigned long ip,
3048 int references)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003049{
3050 struct task_struct *curr = current;
Ingo Molnard6d897c2006-07-10 04:44:04 -07003051 struct lock_class *class = NULL;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003052 struct held_lock *hlock;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003053 unsigned int depth, id;
3054 int chain_head = 0;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003055 int class_idx;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003056 u64 chain_key;
3057
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003058 if (!prove_locking)
3059 check = 1;
3060
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003061 if (unlikely(!debug_locks))
3062 return 0;
3063
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003064 /*
3065 * Lockdep should run with IRQs disabled, otherwise we could
3066 * get an interrupt which would want to take locks, which would
3067 * end up in lockdep and have you got a head-ache already?
3068 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003069 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3070 return 0;
3071
Peter Zijlstra1704f472010-03-19 01:37:42 +01003072 if (lock->key == &__lockdep_no_validate__)
3073 check = 1;
3074
Hitoshi Mitake62016252010-10-05 18:01:51 +09003075 if (subclass < NR_LOCKDEP_CACHING_CLASSES)
3076 class = lock->class_cache[subclass];
Ingo Molnard6d897c2006-07-10 04:44:04 -07003077 /*
Hitoshi Mitake62016252010-10-05 18:01:51 +09003078 * Not cached?
Ingo Molnard6d897c2006-07-10 04:44:04 -07003079 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003080 if (unlikely(!class)) {
Peter Zijlstra4dfbb9d2006-10-11 01:45:14 -04003081 class = register_lock_class(lock, subclass, 0);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003082 if (!class)
3083 return 0;
3084 }
Frederic Weisbeckerbd6d29c2010-04-06 00:10:17 +02003085 atomic_inc((atomic_t *)&class->ops);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003086 if (very_verbose(class)) {
3087 printk("\nacquire class [%p] %s", class->key, class->name);
3088 if (class->name_version > 1)
3089 printk("#%d", class->name_version);
3090 printk("\n");
3091 dump_stack();
3092 }
3093
3094 /*
3095 * Add the lock to the list of currently held locks.
3096 * (we dont increase the depth just yet, up until the
3097 * dependency checks are done)
3098 */
3099 depth = curr->lockdep_depth;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003100 /*
3101 * Ran out of static storage for our per-task lock stack again have we?
3102 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003103 if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
3104 return 0;
3105
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003106 class_idx = class - lock_classes + 1;
3107
3108 if (depth) {
3109 hlock = curr->held_locks + depth - 1;
3110 if (hlock->class_idx == class_idx && nest_lock) {
3111 if (hlock->references)
3112 hlock->references++;
3113 else
3114 hlock->references = 2;
3115
3116 return 1;
3117 }
3118 }
3119
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003120 hlock = curr->held_locks + depth;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003121 /*
3122 * Plain impossible, we just registered it and checked it weren't no
3123 * NULL like.. I bet this mushroom I ate was good!
3124 */
Dave Jonesf82b2172008-08-11 09:30:23 +02003125 if (DEBUG_LOCKS_WARN_ON(!class))
3126 return 0;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003127 hlock->class_idx = class_idx;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003128 hlock->acquire_ip = ip;
3129 hlock->instance = lock;
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02003130 hlock->nest_lock = nest_lock;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003131 hlock->trylock = trylock;
3132 hlock->read = read;
3133 hlock->check = check;
Dmitry Baryshkov6951b122008-08-18 04:26:37 +04003134 hlock->hardirqs_off = !!hardirqs_off;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003135 hlock->references = references;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003136#ifdef CONFIG_LOCK_STAT
3137 hlock->waittime_stamp = 0;
Peter Zijlstra3365e7792009-10-09 10:12:41 +02003138 hlock->holdtime_stamp = lockstat_clock();
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003139#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003140
Peter Zijlstra8e182572007-07-19 01:48:54 -07003141 if (check == 2 && !mark_irqflags(curr, hlock))
3142 return 0;
3143
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003144 /* mark it as used: */
Jarek Poplawski4ff773bb2007-05-08 00:31:00 -07003145 if (!mark_lock(curr, hlock, LOCK_USED))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003146 return 0;
Peter Zijlstra8e182572007-07-19 01:48:54 -07003147
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003148 /*
Gautham R Shenoy17aacfb2007-10-28 20:47:01 +01003149 * Calculate the chain hash: it's the combined hash of all the
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003150 * lock keys along the dependency chain. We save the hash value
3151 * at every step so that we can get the current hash easily
3152 * after unlock. The chain hash is then used to cache dependency
3153 * results.
3154 *
3155 * The 'key ID' is what is the most compact key value to drive
3156 * the hash, not class->key.
3157 */
3158 id = class - lock_classes;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003159 /*
3160 * Whoops, we did it again.. ran straight out of our static allocation.
3161 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003162 if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
3163 return 0;
3164
3165 chain_key = curr->curr_chain_key;
3166 if (!depth) {
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003167 /*
3168 * How can we have a chain hash when we ain't got no keys?!
3169 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003170 if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
3171 return 0;
3172 chain_head = 1;
3173 }
3174
3175 hlock->prev_chain_key = chain_key;
Peter Zijlstra8e182572007-07-19 01:48:54 -07003176 if (separate_irq_context(curr, hlock)) {
3177 chain_key = 0;
3178 chain_head = 1;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003179 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003180 chain_key = iterate_chain_key(chain_key, id);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003181
Maarten Lankhorstd0945952012-09-13 11:39:51 +02003182 if (nest_lock && !__lock_is_held(nest_lock))
3183 return print_lock_nested_lock_not_held(curr, hlock, ip);
3184
Gregory Haskins3aa416b2007-10-11 22:11:11 +02003185 if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
Peter Zijlstra8e182572007-07-19 01:48:54 -07003186 return 0;
Jarek Poplawski381a2292007-02-10 01:44:58 -08003187
Gregory Haskins3aa416b2007-10-11 22:11:11 +02003188 curr->curr_chain_key = chain_key;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003189 curr->lockdep_depth++;
3190 check_chain_key(curr);
Jarek Poplawski60e114d2007-02-20 13:58:00 -08003191#ifdef CONFIG_DEBUG_LOCKDEP
3192 if (unlikely(!debug_locks))
3193 return 0;
3194#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003195 if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
3196 debug_locks_off();
Dave Jones2c522832013-04-25 13:40:02 -04003197 print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
3198 printk(KERN_DEBUG "depth: %i max: %lu!\n",
Ben Greearc0540602013-02-06 10:56:19 -08003199 curr->lockdep_depth, MAX_LOCK_DEPTH);
Ben Greearc0540602013-02-06 10:56:19 -08003200
3201 lockdep_print_held_locks(current);
3202 debug_show_all_locks();
Peter Zijlstraeedeeab2009-03-18 12:38:47 +01003203 dump_stack();
Ben Greearc0540602013-02-06 10:56:19 -08003204
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003205 return 0;
3206 }
Jarek Poplawski381a2292007-02-10 01:44:58 -08003207
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003208 if (unlikely(curr->lockdep_depth > max_lockdep_depth))
3209 max_lockdep_depth = curr->lockdep_depth;
3210
3211 return 1;
3212}
3213
3214static int
Srivatsa S. Bhatf86f7552013-01-08 18:35:58 +05303215print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003216 unsigned long ip)
3217{
3218 if (!debug_locks_off())
3219 return 0;
3220 if (debug_locks_silent)
3221 return 0;
3222
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07003223 printk("\n");
3224 printk("=====================================\n");
3225 printk("[ BUG: bad unlock balance detected! ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01003226 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07003227 printk("-------------------------------------\n");
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003228 printk("%s/%d is trying to release lock (",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07003229 curr->comm, task_pid_nr(curr));
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003230 print_lockdep_cache(lock);
3231 printk(") at:\n");
3232 print_ip_sym(ip);
3233 printk("but there are no more locks to release!\n");
3234 printk("\nother info that might help us debug this:\n");
3235 lockdep_print_held_locks(curr);
3236
3237 printk("\nstack backtrace:\n");
3238 dump_stack();
3239
3240 return 0;
3241}
3242
3243/*
3244 * Common debugging checks for both nested and non-nested unlock:
3245 */
3246static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
3247 unsigned long ip)
3248{
3249 if (unlikely(!debug_locks))
3250 return 0;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003251 /*
3252 * Lockdep should run with IRQs disabled, recursion, head-ache, etc..
3253 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003254 if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
3255 return 0;
3256
3257 if (curr->lockdep_depth <= 0)
Srivatsa S. Bhatf86f7552013-01-08 18:35:58 +05303258 return print_unlock_imbalance_bug(curr, lock, ip);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003259
3260 return 1;
3261}
3262
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003263static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock)
3264{
3265 if (hlock->instance == lock)
3266 return 1;
3267
3268 if (hlock->references) {
Hitoshi Mitake62016252010-10-05 18:01:51 +09003269 struct lock_class *class = lock->class_cache[0];
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003270
3271 if (!class)
3272 class = look_up_lock_class(lock, 0);
3273
Peter Zijlstra80e04012011-08-05 14:26:17 +02003274 /*
3275 * If look_up_lock_class() failed to find a class, we're trying
3276 * to test if we hold a lock that has never yet been acquired.
3277 * Clearly if the lock hasn't been acquired _ever_, we're not
3278 * holding it either, so report failure.
3279 */
3280 if (!class)
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003281 return 0;
3282
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003283 /*
3284 * References, but not a lock we're actually ref-counting?
3285 * State got messed up, follow the sites that change ->references
3286 * and try to make sense of it.
3287 */
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003288 if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock))
3289 return 0;
3290
3291 if (hlock->class_idx == class - lock_classes + 1)
3292 return 1;
3293 }
3294
3295 return 0;
3296}
3297
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003298static int
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003299__lock_set_class(struct lockdep_map *lock, const char *name,
3300 struct lock_class_key *key, unsigned int subclass,
3301 unsigned long ip)
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003302{
3303 struct task_struct *curr = current;
3304 struct held_lock *hlock, *prev_hlock;
3305 struct lock_class *class;
3306 unsigned int depth;
3307 int i;
3308
3309 depth = curr->lockdep_depth;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003310 /*
3311 * This function is about (re)setting the class of a held lock,
3312 * yet we're not actually holding any locks. Naughty user!
3313 */
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003314 if (DEBUG_LOCKS_WARN_ON(!depth))
3315 return 0;
3316
3317 prev_hlock = NULL;
3318 for (i = depth-1; i >= 0; i--) {
3319 hlock = curr->held_locks + i;
3320 /*
3321 * We must not cross into another context:
3322 */
3323 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3324 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003325 if (match_held_lock(hlock, lock))
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003326 goto found_it;
3327 prev_hlock = hlock;
3328 }
Srivatsa S. Bhatf86f7552013-01-08 18:35:58 +05303329 return print_unlock_imbalance_bug(curr, lock, ip);
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003330
3331found_it:
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003332 lockdep_init_map(lock, name, key, 0);
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003333 class = register_lock_class(lock, subclass, 0);
Dave Jonesf82b2172008-08-11 09:30:23 +02003334 hlock->class_idx = class - lock_classes + 1;
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003335
3336 curr->lockdep_depth = i;
3337 curr->curr_chain_key = hlock->prev_chain_key;
3338
3339 for (; i < depth; i++) {
3340 hlock = curr->held_locks + i;
3341 if (!__lock_acquire(hlock->instance,
Dave Jonesf82b2172008-08-11 09:30:23 +02003342 hlock_class(hlock)->subclass, hlock->trylock,
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003343 hlock->read, hlock->check, hlock->hardirqs_off,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003344 hlock->nest_lock, hlock->acquire_ip,
3345 hlock->references))
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003346 return 0;
3347 }
3348
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003349 /*
3350 * I took it apart and put it back together again, except now I have
3351 * these 'spare' parts.. where shall I put them.
3352 */
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003353 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth))
3354 return 0;
3355 return 1;
3356}
3357
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003358/*
3359 * Remove the lock to the list of currently held locks in a
3360 * potentially non-nested (out of order) manner. This is a
3361 * relatively rare operation, as all the unlock APIs default
3362 * to nested mode (which uses lock_release()):
3363 */
3364static int
3365lock_release_non_nested(struct task_struct *curr,
3366 struct lockdep_map *lock, unsigned long ip)
3367{
3368 struct held_lock *hlock, *prev_hlock;
3369 unsigned int depth;
3370 int i;
3371
3372 /*
3373 * Check whether the lock exists in the current stack
3374 * of held locks:
3375 */
3376 depth = curr->lockdep_depth;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003377 /*
3378 * So we're all set to release this lock.. wait what lock? We don't
3379 * own any locks, you've been drinking again?
3380 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003381 if (DEBUG_LOCKS_WARN_ON(!depth))
3382 return 0;
3383
3384 prev_hlock = NULL;
3385 for (i = depth-1; i >= 0; i--) {
3386 hlock = curr->held_locks + i;
3387 /*
3388 * We must not cross into another context:
3389 */
3390 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3391 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003392 if (match_held_lock(hlock, lock))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003393 goto found_it;
3394 prev_hlock = hlock;
3395 }
Srivatsa S. Bhatf86f7552013-01-08 18:35:58 +05303396 return print_unlock_imbalance_bug(curr, lock, ip);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003397
3398found_it:
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003399 if (hlock->instance == lock)
3400 lock_release_holdtime(hlock);
3401
3402 if (hlock->references) {
3403 hlock->references--;
3404 if (hlock->references) {
3405 /*
3406 * We had, and after removing one, still have
3407 * references, the current lock stack is still
3408 * valid. We're done!
3409 */
3410 return 1;
3411 }
3412 }
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003413
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003414 /*
3415 * We have the right lock to unlock, 'hlock' points to it.
3416 * Now we remove it from the stack, and add back the other
3417 * entries (if any), recalculating the hash along the way:
3418 */
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003419
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003420 curr->lockdep_depth = i;
3421 curr->curr_chain_key = hlock->prev_chain_key;
3422
3423 for (i++; i < depth; i++) {
3424 hlock = curr->held_locks + i;
3425 if (!__lock_acquire(hlock->instance,
Dave Jonesf82b2172008-08-11 09:30:23 +02003426 hlock_class(hlock)->subclass, hlock->trylock,
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003427 hlock->read, hlock->check, hlock->hardirqs_off,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003428 hlock->nest_lock, hlock->acquire_ip,
3429 hlock->references))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003430 return 0;
3431 }
3432
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003433 /*
3434 * We had N bottles of beer on the wall, we drank one, but now
3435 * there's not N-1 bottles of beer left on the wall...
3436 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003437 if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
3438 return 0;
3439 return 1;
3440}
3441
3442/*
3443 * Remove the lock to the list of currently held locks - this gets
3444 * called on mutex_unlock()/spin_unlock*() (or on a failed
3445 * mutex_lock_interruptible()). This is done for unlocks that nest
3446 * perfectly. (i.e. the current top of the lock-stack is unlocked)
3447 */
3448static int lock_release_nested(struct task_struct *curr,
3449 struct lockdep_map *lock, unsigned long ip)
3450{
3451 struct held_lock *hlock;
3452 unsigned int depth;
3453
3454 /*
3455 * Pop off the top of the lock stack:
3456 */
3457 depth = curr->lockdep_depth - 1;
3458 hlock = curr->held_locks + depth;
3459
3460 /*
3461 * Is the unlock non-nested:
3462 */
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003463 if (hlock->instance != lock || hlock->references)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003464 return lock_release_non_nested(curr, lock, ip);
3465 curr->lockdep_depth--;
3466
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003467 /*
3468 * No more locks, but somehow we've got hash left over, who left it?
3469 */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003470 if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
3471 return 0;
3472
3473 curr->curr_chain_key = hlock->prev_chain_key;
3474
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003475 lock_release_holdtime(hlock);
3476
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003477#ifdef CONFIG_DEBUG_LOCKDEP
3478 hlock->prev_chain_key = 0;
Dave Jonesf82b2172008-08-11 09:30:23 +02003479 hlock->class_idx = 0;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003480 hlock->acquire_ip = 0;
3481 hlock->irq_context = 0;
3482#endif
3483 return 1;
3484}
3485
3486/*
3487 * Remove the lock to the list of currently held locks - this gets
3488 * called on mutex_unlock()/spin_unlock*() (or on a failed
3489 * mutex_lock_interruptible()). This is done for unlocks that nest
3490 * perfectly. (i.e. the current top of the lock-stack is unlocked)
3491 */
3492static void
3493__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
3494{
3495 struct task_struct *curr = current;
3496
3497 if (!check_unlock(curr, lock, ip))
3498 return;
3499
3500 if (nested) {
3501 if (!lock_release_nested(curr, lock, ip))
3502 return;
3503 } else {
3504 if (!lock_release_non_nested(curr, lock, ip))
3505 return;
3506 }
3507
3508 check_chain_key(curr);
3509}
3510
Peter Zijlstraf607c662009-07-20 19:16:29 +02003511static int __lock_is_held(struct lockdep_map *lock)
3512{
3513 struct task_struct *curr = current;
3514 int i;
3515
3516 for (i = 0; i < curr->lockdep_depth; i++) {
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003517 struct held_lock *hlock = curr->held_locks + i;
3518
3519 if (match_held_lock(hlock, lock))
Peter Zijlstraf607c662009-07-20 19:16:29 +02003520 return 1;
3521 }
3522
3523 return 0;
3524}
3525
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003526/*
3527 * Check whether we follow the irq-flags state precisely:
3528 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02003529static void check_flags(unsigned long flags)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003530{
Ingo Molnar992860e2008-07-14 10:28:38 +02003531#if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \
3532 defined(CONFIG_TRACE_IRQFLAGS)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003533 if (!debug_locks)
3534 return;
3535
Ingo Molnar5f9fa8a2007-12-07 19:02:47 +01003536 if (irqs_disabled_flags(flags)) {
3537 if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
3538 printk("possible reason: unannotated irqs-off.\n");
3539 }
3540 } else {
3541 if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
3542 printk("possible reason: unannotated irqs-on.\n");
3543 }
3544 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003545
3546 /*
3547 * We dont accurately track softirq state in e.g.
3548 * hardirq contexts (such as on 4KSTACKS), so only
3549 * check if not in hardirq contexts:
3550 */
3551 if (!hardirq_count()) {
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003552 if (softirq_count()) {
3553 /* like the above, but with softirqs */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003554 DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003555 } else {
3556 /* lick the above, does it taste good? */
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003557 DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003558 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003559 }
3560
3561 if (!debug_locks)
3562 print_irqtrace_events(current);
3563#endif
3564}
3565
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003566void lock_set_class(struct lockdep_map *lock, const char *name,
3567 struct lock_class_key *key, unsigned int subclass,
3568 unsigned long ip)
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003569{
3570 unsigned long flags;
3571
3572 if (unlikely(current->lockdep_recursion))
3573 return;
3574
3575 raw_local_irq_save(flags);
3576 current->lockdep_recursion = 1;
3577 check_flags(flags);
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003578 if (__lock_set_class(lock, name, key, subclass, ip))
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003579 check_chain_key(current);
3580 current->lockdep_recursion = 0;
3581 raw_local_irq_restore(flags);
3582}
Peter Zijlstra00ef9f72008-12-04 09:00:17 +01003583EXPORT_SYMBOL_GPL(lock_set_class);
Peter Zijlstra64aa3482008-08-11 09:30:21 +02003584
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003585/*
3586 * We are not always called with irqs disabled - do that here,
3587 * and also avoid lockdep recursion:
3588 */
Steven Rostedt1d09daa2008-05-12 21:20:55 +02003589void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
Peter Zijlstra7531e2f2008-08-11 09:30:24 +02003590 int trylock, int read, int check,
3591 struct lockdep_map *nest_lock, unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003592{
3593 unsigned long flags;
3594
3595 if (unlikely(current->lockdep_recursion))
3596 return;
3597
3598 raw_local_irq_save(flags);
3599 check_flags(flags);
3600
3601 current->lockdep_recursion = 1;
Frederic Weisbeckerdb2c4c72010-02-02 23:34:40 +01003602 trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003603 __lock_acquire(lock, subclass, trylock, read, check,
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003604 irqs_disabled_flags(flags), nest_lock, ip, 0);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003605 current->lockdep_recursion = 0;
3606 raw_local_irq_restore(flags);
3607}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003608EXPORT_SYMBOL_GPL(lock_acquire);
3609
Steven Rostedt1d09daa2008-05-12 21:20:55 +02003610void lock_release(struct lockdep_map *lock, int nested,
Steven Rostedt0764d232008-05-12 21:20:44 +02003611 unsigned long ip)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003612{
3613 unsigned long flags;
3614
3615 if (unlikely(current->lockdep_recursion))
3616 return;
3617
3618 raw_local_irq_save(flags);
3619 check_flags(flags);
3620 current->lockdep_recursion = 1;
Frederic Weisbecker93135432010-05-08 06:24:25 +02003621 trace_lock_release(lock, ip);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003622 __lock_release(lock, nested, ip);
3623 current->lockdep_recursion = 0;
3624 raw_local_irq_restore(flags);
3625}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003626EXPORT_SYMBOL_GPL(lock_release);
3627
Peter Zijlstraf607c662009-07-20 19:16:29 +02003628int lock_is_held(struct lockdep_map *lock)
3629{
3630 unsigned long flags;
3631 int ret = 0;
3632
3633 if (unlikely(current->lockdep_recursion))
Peter Zijlstraf2513cd2011-06-06 12:32:43 +02003634 return 1; /* avoid false negative lockdep_assert_held() */
Peter Zijlstraf607c662009-07-20 19:16:29 +02003635
3636 raw_local_irq_save(flags);
3637 check_flags(flags);
3638
3639 current->lockdep_recursion = 1;
3640 ret = __lock_is_held(lock);
3641 current->lockdep_recursion = 0;
3642 raw_local_irq_restore(flags);
3643
3644 return ret;
3645}
3646EXPORT_SYMBOL_GPL(lock_is_held);
3647
Nick Piggincf40bd12009-01-21 08:12:39 +01003648void lockdep_set_current_reclaim_state(gfp_t gfp_mask)
3649{
3650 current->lockdep_reclaim_gfp = gfp_mask;
3651}
3652
3653void lockdep_clear_current_reclaim_state(void)
3654{
3655 current->lockdep_reclaim_gfp = 0;
3656}
3657
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003658#ifdef CONFIG_LOCK_STAT
3659static int
3660print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
3661 unsigned long ip)
3662{
3663 if (!debug_locks_off())
3664 return 0;
3665 if (debug_locks_silent)
3666 return 0;
3667
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07003668 printk("\n");
3669 printk("=================================\n");
3670 printk("[ BUG: bad contention detected! ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01003671 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07003672 printk("---------------------------------\n");
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003673 printk("%s/%d is trying to contend lock (",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07003674 curr->comm, task_pid_nr(curr));
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003675 print_lockdep_cache(lock);
3676 printk(") at:\n");
3677 print_ip_sym(ip);
3678 printk("but there are no locks held!\n");
3679 printk("\nother info that might help us debug this:\n");
3680 lockdep_print_held_locks(curr);
3681
3682 printk("\nstack backtrace:\n");
3683 dump_stack();
3684
3685 return 0;
3686}
3687
3688static void
3689__lock_contended(struct lockdep_map *lock, unsigned long ip)
3690{
3691 struct task_struct *curr = current;
3692 struct held_lock *hlock, *prev_hlock;
3693 struct lock_class_stats *stats;
3694 unsigned int depth;
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003695 int i, contention_point, contending_point;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003696
3697 depth = curr->lockdep_depth;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003698 /*
3699 * Whee, we contended on this lock, except it seems we're not
3700 * actually trying to acquire anything much at all..
3701 */
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003702 if (DEBUG_LOCKS_WARN_ON(!depth))
3703 return;
3704
3705 prev_hlock = NULL;
3706 for (i = depth-1; i >= 0; i--) {
3707 hlock = curr->held_locks + i;
3708 /*
3709 * We must not cross into another context:
3710 */
3711 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3712 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003713 if (match_held_lock(hlock, lock))
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003714 goto found_it;
3715 prev_hlock = hlock;
3716 }
3717 print_lock_contention_bug(curr, lock, ip);
3718 return;
3719
3720found_it:
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003721 if (hlock->instance != lock)
3722 return;
3723
Peter Zijlstra3365e7792009-10-09 10:12:41 +02003724 hlock->waittime_stamp = lockstat_clock();
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003725
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003726 contention_point = lock_point(hlock_class(hlock)->contention_point, ip);
3727 contending_point = lock_point(hlock_class(hlock)->contending_point,
3728 lock->ip);
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003729
Dave Jonesf82b2172008-08-11 09:30:23 +02003730 stats = get_lock_stats(hlock_class(hlock));
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003731 if (contention_point < LOCKSTAT_POINTS)
3732 stats->contention_point[contention_point]++;
3733 if (contending_point < LOCKSTAT_POINTS)
3734 stats->contending_point[contending_point]++;
Peter Zijlstra96645672007-07-19 01:49:00 -07003735 if (lock->cpu != smp_processor_id())
3736 stats->bounces[bounce_contended + !!hlock->read]++;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003737 put_lock_stats(stats);
3738}
3739
3740static void
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003741__lock_acquired(struct lockdep_map *lock, unsigned long ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003742{
3743 struct task_struct *curr = current;
3744 struct held_lock *hlock, *prev_hlock;
3745 struct lock_class_stats *stats;
3746 unsigned int depth;
Peter Zijlstra3365e7792009-10-09 10:12:41 +02003747 u64 now, waittime = 0;
Peter Zijlstra96645672007-07-19 01:49:00 -07003748 int i, cpu;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003749
3750 depth = curr->lockdep_depth;
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003751 /*
3752 * Yay, we acquired ownership of this lock we didn't try to
3753 * acquire, how the heck did that happen?
3754 */
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003755 if (DEBUG_LOCKS_WARN_ON(!depth))
3756 return;
3757
3758 prev_hlock = NULL;
3759 for (i = depth-1; i >= 0; i--) {
3760 hlock = curr->held_locks + i;
3761 /*
3762 * We must not cross into another context:
3763 */
3764 if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
3765 break;
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003766 if (match_held_lock(hlock, lock))
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003767 goto found_it;
3768 prev_hlock = hlock;
3769 }
3770 print_lock_contention_bug(curr, lock, _RET_IP_);
3771 return;
3772
3773found_it:
Peter Zijlstrabb97a912009-07-20 19:15:35 +02003774 if (hlock->instance != lock)
3775 return;
3776
Peter Zijlstra96645672007-07-19 01:49:00 -07003777 cpu = smp_processor_id();
3778 if (hlock->waittime_stamp) {
Peter Zijlstra3365e7792009-10-09 10:12:41 +02003779 now = lockstat_clock();
Peter Zijlstra96645672007-07-19 01:49:00 -07003780 waittime = now - hlock->waittime_stamp;
3781 hlock->holdtime_stamp = now;
3782 }
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003783
Frederic Weisbecker883a2a32010-05-08 06:16:11 +02003784 trace_lock_acquired(lock, ip);
Frederic Weisbecker20625012009-04-06 01:49:33 +02003785
Dave Jonesf82b2172008-08-11 09:30:23 +02003786 stats = get_lock_stats(hlock_class(hlock));
Peter Zijlstra96645672007-07-19 01:49:00 -07003787 if (waittime) {
3788 if (hlock->read)
3789 lock_time_inc(&stats->read_waittime, waittime);
3790 else
3791 lock_time_inc(&stats->write_waittime, waittime);
3792 }
3793 if (lock->cpu != cpu)
3794 stats->bounces[bounce_acquired + !!hlock->read]++;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003795 put_lock_stats(stats);
Peter Zijlstra96645672007-07-19 01:49:00 -07003796
3797 lock->cpu = cpu;
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003798 lock->ip = ip;
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003799}
3800
3801void lock_contended(struct lockdep_map *lock, unsigned long ip)
3802{
3803 unsigned long flags;
3804
3805 if (unlikely(!lock_stat))
3806 return;
3807
3808 if (unlikely(current->lockdep_recursion))
3809 return;
3810
3811 raw_local_irq_save(flags);
3812 check_flags(flags);
3813 current->lockdep_recursion = 1;
Frederic Weisbeckerdb2c4c72010-02-02 23:34:40 +01003814 trace_lock_contended(lock, ip);
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003815 __lock_contended(lock, ip);
3816 current->lockdep_recursion = 0;
3817 raw_local_irq_restore(flags);
3818}
3819EXPORT_SYMBOL_GPL(lock_contended);
3820
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003821void lock_acquired(struct lockdep_map *lock, unsigned long ip)
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003822{
3823 unsigned long flags;
3824
3825 if (unlikely(!lock_stat))
3826 return;
3827
3828 if (unlikely(current->lockdep_recursion))
3829 return;
3830
3831 raw_local_irq_save(flags);
3832 check_flags(flags);
3833 current->lockdep_recursion = 1;
Peter Zijlstrac7e78cf2008-10-16 23:17:09 +02003834 __lock_acquired(lock, ip);
Peter Zijlstraf20786f2007-07-19 01:48:56 -07003835 current->lockdep_recursion = 0;
3836 raw_local_irq_restore(flags);
3837}
3838EXPORT_SYMBOL_GPL(lock_acquired);
3839#endif
3840
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003841/*
3842 * Used by the testsuite, sanitize the validator state
3843 * after a simulated failure:
3844 */
3845
3846void lockdep_reset(void)
3847{
3848 unsigned long flags;
Ingo Molnar23d95a02006-12-13 00:34:40 -08003849 int i;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003850
3851 raw_local_irq_save(flags);
3852 current->curr_chain_key = 0;
3853 current->lockdep_depth = 0;
3854 current->lockdep_recursion = 0;
3855 memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
3856 nr_hardirq_chains = 0;
3857 nr_softirq_chains = 0;
3858 nr_process_chains = 0;
3859 debug_locks = 1;
Ingo Molnar23d95a02006-12-13 00:34:40 -08003860 for (i = 0; i < CHAINHASH_SIZE; i++)
3861 INIT_LIST_HEAD(chainhash_table + i);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003862 raw_local_irq_restore(flags);
3863}
3864
3865static void zap_class(struct lock_class *class)
3866{
3867 int i;
3868
3869 /*
3870 * Remove all dependencies this lock is
3871 * involved in:
3872 */
3873 for (i = 0; i < nr_list_entries; i++) {
3874 if (list_entries[i].class == class)
3875 list_del_rcu(&list_entries[i].entry);
3876 }
3877 /*
3878 * Unhash the class and remove it from the all_lock_classes list:
3879 */
3880 list_del_rcu(&class->hash_entry);
3881 list_del_rcu(&class->lock_entry);
3882
Rabin Vincent8bfe0292008-08-11 09:30:26 +02003883 class->key = NULL;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003884}
3885
Arjan van de Venfabe8742008-01-24 07:00:45 +01003886static inline int within(const void *addr, void *start, unsigned long size)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003887{
3888 return addr >= start && addr < start + size;
3889}
3890
3891void lockdep_free_key_range(void *start, unsigned long size)
3892{
3893 struct lock_class *class, *next;
3894 struct list_head *head;
3895 unsigned long flags;
3896 int i;
Nick Piggin5a26db52008-01-16 09:51:58 +01003897 int locked;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003898
3899 raw_local_irq_save(flags);
Nick Piggin5a26db52008-01-16 09:51:58 +01003900 locked = graph_lock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003901
3902 /*
3903 * Unhash all classes that were created by this module:
3904 */
3905 for (i = 0; i < CLASSHASH_SIZE; i++) {
3906 head = classhash_table + i;
3907 if (list_empty(head))
3908 continue;
Arjan van de Venfabe8742008-01-24 07:00:45 +01003909 list_for_each_entry_safe(class, next, head, hash_entry) {
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003910 if (within(class->key, start, size))
3911 zap_class(class);
Arjan van de Venfabe8742008-01-24 07:00:45 +01003912 else if (within(class->name, start, size))
3913 zap_class(class);
3914 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003915 }
3916
Nick Piggin5a26db52008-01-16 09:51:58 +01003917 if (locked)
3918 graph_unlock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003919 raw_local_irq_restore(flags);
3920}
3921
3922void lockdep_reset_lock(struct lockdep_map *lock)
3923{
Ingo Molnard6d897c2006-07-10 04:44:04 -07003924 struct lock_class *class, *next;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003925 struct list_head *head;
3926 unsigned long flags;
3927 int i, j;
Nick Piggin5a26db52008-01-16 09:51:58 +01003928 int locked;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003929
3930 raw_local_irq_save(flags);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003931
3932 /*
Ingo Molnard6d897c2006-07-10 04:44:04 -07003933 * Remove all classes this lock might have:
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003934 */
Ingo Molnard6d897c2006-07-10 04:44:04 -07003935 for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
3936 /*
3937 * If the class exists we look it up and zap it:
3938 */
3939 class = look_up_lock_class(lock, j);
3940 if (class)
3941 zap_class(class);
3942 }
3943 /*
3944 * Debug check: in the end all mapped classes should
3945 * be gone.
3946 */
Nick Piggin5a26db52008-01-16 09:51:58 +01003947 locked = graph_lock();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003948 for (i = 0; i < CLASSHASH_SIZE; i++) {
3949 head = classhash_table + i;
3950 if (list_empty(head))
3951 continue;
3952 list_for_each_entry_safe(class, next, head, hash_entry) {
Hitoshi Mitake62016252010-10-05 18:01:51 +09003953 int match = 0;
3954
3955 for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++)
3956 match |= class == lock->class_cache[j];
3957
3958 if (unlikely(match)) {
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003959 if (debug_locks_off_graph_unlock()) {
3960 /*
3961 * We all just reset everything, how did it match?
3962 */
Ingo Molnar74c383f2006-12-13 00:34:43 -08003963 WARN_ON(1);
Peter Zijlstra0119fee2011-09-02 01:30:29 +02003964 }
Ingo Molnard6d897c2006-07-10 04:44:04 -07003965 goto out_restore;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003966 }
3967 }
3968 }
Nick Piggin5a26db52008-01-16 09:51:58 +01003969 if (locked)
3970 graph_unlock();
Ingo Molnard6d897c2006-07-10 04:44:04 -07003971
3972out_restore:
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003973 raw_local_irq_restore(flags);
3974}
3975
Sam Ravnborg14999932007-02-28 20:12:31 -08003976void lockdep_init(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07003977{
3978 int i;
3979
3980 /*
3981 * Some architectures have their own start_kernel()
3982 * code which calls lockdep_init(), while we also
3983 * call lockdep_init() from the start_kernel() itself,
3984 * and we want to initialize the hashes only once:
3985 */
3986 if (lockdep_initialized)
3987 return;
3988
3989 for (i = 0; i < CLASSHASH_SIZE; i++)
3990 INIT_LIST_HEAD(classhash_table + i);
3991
3992 for (i = 0; i < CHAINHASH_SIZE; i++)
3993 INIT_LIST_HEAD(chainhash_table + i);
3994
3995 lockdep_initialized = 1;
3996}
3997
3998void __init lockdep_info(void)
3999{
4000 printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
4001
Li Zefanb0788ca2008-11-21 15:57:32 +08004002 printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004003 printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
4004 printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
Li Zefanb0788ca2008-11-21 15:57:32 +08004005 printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004006 printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
4007 printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS);
4008 printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE);
4009
4010 printk(" memory used by lock dependency info: %lu kB\n",
4011 (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
4012 sizeof(struct list_head) * CLASSHASH_SIZE +
4013 sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
4014 sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
Ming Lei90629202009-08-02 21:43:36 +08004015 sizeof(struct list_head) * CHAINHASH_SIZE
Ming Lei4dd861d2009-07-16 15:44:29 +02004016#ifdef CONFIG_PROVE_LOCKING
Ming Leie351b662009-07-22 22:48:09 +08004017 + sizeof(struct circular_queue)
Ming Lei4dd861d2009-07-16 15:44:29 +02004018#endif
Ming Lei90629202009-08-02 21:43:36 +08004019 ) / 1024
Ming Lei4dd861d2009-07-16 15:44:29 +02004020 );
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004021
4022 printk(" per task-struct memory footprint: %lu bytes\n",
4023 sizeof(struct held_lock) * MAX_LOCK_DEPTH);
4024
4025#ifdef CONFIG_DEBUG_LOCKDEP
Johannes Bergc71063c2007-07-19 01:49:02 -07004026 if (lockdep_init_error) {
Ming Lei81140ac2011-11-17 13:34:32 +08004027 printk("WARNING: lockdep init error! lock-%s was acquired"
4028 "before lockdep_init\n", lock_init_error);
Johannes Bergc71063c2007-07-19 01:49:02 -07004029 printk("Call stack leading to lockdep invocation was:\n");
4030 print_stack_trace(&lockdep_init_trace, 0);
4031 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004032#endif
4033}
4034
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004035static void
4036print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
Arjan van de Ven55794a42006-07-10 04:44:03 -07004037 const void *mem_to, struct held_lock *hlock)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004038{
4039 if (!debug_locks_off())
4040 return;
4041 if (debug_locks_silent)
4042 return;
4043
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004044 printk("\n");
4045 printk("=========================\n");
4046 printk("[ BUG: held lock freed! ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01004047 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004048 printk("-------------------------\n");
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004049 printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07004050 curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
Arjan van de Ven55794a42006-07-10 04:44:03 -07004051 print_lock(hlock);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004052 lockdep_print_held_locks(curr);
4053
4054 printk("\nstack backtrace:\n");
4055 dump_stack();
4056}
4057
Oleg Nesterov54561782007-12-05 15:46:09 +01004058static inline int not_in_range(const void* mem_from, unsigned long mem_len,
4059 const void* lock_from, unsigned long lock_len)
4060{
4061 return lock_from + lock_len <= mem_from ||
4062 mem_from + mem_len <= lock_from;
4063}
4064
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004065/*
4066 * Called when kernel memory is freed (or unmapped), or if a lock
4067 * is destroyed or reinitialized - this code checks whether there is
4068 * any held lock in the memory range of <from> to <to>:
4069 */
4070void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
4071{
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004072 struct task_struct *curr = current;
4073 struct held_lock *hlock;
4074 unsigned long flags;
4075 int i;
4076
4077 if (unlikely(!debug_locks))
4078 return;
4079
4080 local_irq_save(flags);
4081 for (i = 0; i < curr->lockdep_depth; i++) {
4082 hlock = curr->held_locks + i;
4083
Oleg Nesterov54561782007-12-05 15:46:09 +01004084 if (not_in_range(mem_from, mem_len, hlock->instance,
4085 sizeof(*hlock->instance)))
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004086 continue;
4087
Oleg Nesterov54561782007-12-05 15:46:09 +01004088 print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004089 break;
4090 }
4091 local_irq_restore(flags);
4092}
Peter Zijlstraed075362006-12-06 20:35:24 -08004093EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004094
Colin Cross1b1d2fb2013-05-06 23:50:08 +00004095static void print_held_locks_bug(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004096{
4097 if (!debug_locks_off())
4098 return;
4099 if (debug_locks_silent)
4100 return;
4101
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004102 printk("\n");
4103 printk("=====================================\n");
Colin Cross1b1d2fb2013-05-06 23:50:08 +00004104 printk("[ BUG: %s/%d still has locks held! ]\n",
4105 current->comm, task_pid_nr(current));
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01004106 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004107 printk("-------------------------------------\n");
Colin Cross1b1d2fb2013-05-06 23:50:08 +00004108 lockdep_print_held_locks(current);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004109 printk("\nstack backtrace:\n");
4110 dump_stack();
4111}
4112
Colin Cross1b1d2fb2013-05-06 23:50:08 +00004113void debug_check_no_locks_held(void)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004114{
Colin Cross1b1d2fb2013-05-06 23:50:08 +00004115 if (unlikely(current->lockdep_depth > 0))
4116 print_held_locks_bug();
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004117}
Colin Cross1b1d2fb2013-05-06 23:50:08 +00004118EXPORT_SYMBOL_GPL(debug_check_no_locks_held);
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004119
Sasha Levin8dce7a92013-06-13 18:41:16 -04004120#ifdef __KERNEL__
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004121void debug_show_all_locks(void)
4122{
4123 struct task_struct *g, *p;
4124 int count = 10;
4125 int unlock = 1;
4126
Jarek Poplawski9c35dd72007-03-22 00:11:28 -08004127 if (unlikely(!debug_locks)) {
4128 printk("INFO: lockdep is turned off.\n");
4129 return;
4130 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004131 printk("\nShowing all locks held in the system:\n");
4132
4133 /*
4134 * Here we try to get the tasklist_lock as hard as possible,
4135 * if not successful after 2 seconds we ignore it (but keep
4136 * trying). This is to enable a debug printout even if a
4137 * tasklist_lock-holding task deadlocks or crashes.
4138 */
4139retry:
4140 if (!read_trylock(&tasklist_lock)) {
4141 if (count == 10)
4142 printk("hm, tasklist_lock locked, retrying... ");
4143 if (count) {
4144 count--;
4145 printk(" #%d", 10-count);
4146 mdelay(200);
4147 goto retry;
4148 }
4149 printk(" ignoring it.\n");
4150 unlock = 0;
qinghuang feng46fec7a2008-10-28 17:24:28 +08004151 } else {
4152 if (count != 10)
4153 printk(KERN_CONT " locked it.\n");
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004154 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004155
4156 do_each_thread(g, p) {
Ingo Molnar85684872007-12-05 15:46:09 +01004157 /*
4158 * It's not reliable to print a task's held locks
4159 * if it's not sleeping (or if it's not the current
4160 * task):
4161 */
4162 if (p->state == TASK_RUNNING && p != current)
4163 continue;
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004164 if (p->lockdep_depth)
4165 lockdep_print_held_locks(p);
4166 if (!unlock)
4167 if (read_trylock(&tasklist_lock))
4168 unlock = 1;
4169 } while_each_thread(g, p);
4170
4171 printk("\n");
4172 printk("=============================================\n\n");
4173
4174 if (unlock)
4175 read_unlock(&tasklist_lock);
4176}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004177EXPORT_SYMBOL_GPL(debug_show_all_locks);
Sasha Levin8dce7a92013-06-13 18:41:16 -04004178#endif
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004179
Ingo Molnar82a1fcb2008-01-25 21:08:02 +01004180/*
4181 * Careful: only use this function if you are sure that
4182 * the task cannot run in parallel!
4183 */
John Kacurf1b499f2010-08-05 17:10:53 +02004184void debug_show_held_locks(struct task_struct *task)
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004185{
Jarek Poplawski9c35dd72007-03-22 00:11:28 -08004186 if (unlikely(!debug_locks)) {
4187 printk("INFO: lockdep is turned off.\n");
4188 return;
4189 }
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004190 lockdep_print_held_locks(task);
4191}
Ingo Molnarfbb9ce952006-07-03 00:24:50 -07004192EXPORT_SYMBOL_GPL(debug_show_held_locks);
Peter Zijlstrab351d162007-10-11 22:11:12 +02004193
Andi Kleen63f9a7f2014-02-08 08:52:01 +01004194asmlinkage void lockdep_sys_exit(void)
Peter Zijlstrab351d162007-10-11 22:11:12 +02004195{
4196 struct task_struct *curr = current;
4197
4198 if (unlikely(curr->lockdep_depth)) {
4199 if (!debug_locks_off())
4200 return;
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004201 printk("\n");
4202 printk("================================================\n");
4203 printk("[ BUG: lock held when returning to user space! ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01004204 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004205 printk("------------------------------------------------\n");
Peter Zijlstrab351d162007-10-11 22:11:12 +02004206 printk("%s/%d is leaving the kernel with locks still held!\n",
4207 curr->comm, curr->pid);
4208 lockdep_print_held_locks(curr);
4209 }
4210}
Paul E. McKenney0632eb32010-02-22 17:04:47 -08004211
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004212void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
Paul E. McKenney0632eb32010-02-22 17:04:47 -08004213{
4214 struct task_struct *curr = current;
4215
Lai Jiangshan2b3fc352010-04-20 16:23:07 +08004216#ifndef CONFIG_PROVE_RCU_REPEATEDLY
Paul E. McKenney0632eb32010-02-22 17:04:47 -08004217 if (!debug_locks_off())
4218 return;
Lai Jiangshan2b3fc352010-04-20 16:23:07 +08004219#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
4220 /* Note: the following can be executed concurrently, so be careful. */
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004221 printk("\n");
4222 printk("===============================\n");
4223 printk("[ INFO: suspicious RCU usage. ]\n");
Ben Hutchingsfbdc4b92011-10-28 04:36:55 +01004224 print_kernel_ident();
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004225 printk("-------------------------------\n");
4226 printk("%s:%d %s!\n", file, line, s);
Paul E. McKenney0632eb32010-02-22 17:04:47 -08004227 printk("\nother info that might help us debug this:\n\n");
Paul E. McKenneyc5fdcec2012-01-30 08:46:32 -08004228 printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
4229 !rcu_lockdep_current_cpu_online()
4230 ? "RCU used illegally from offline CPU!\n"
Paul E. McKenney5c173eb2013-09-13 17:20:11 -07004231 : !rcu_is_watching()
Paul E. McKenneyc5fdcec2012-01-30 08:46:32 -08004232 ? "RCU used illegally from idle CPU!\n"
4233 : "",
4234 rcu_scheduler_active, debug_locks);
Frederic Weisbecker0464e932011-10-07 18:22:01 +02004235
4236 /*
4237 * If a CPU is in the RCU-free window in idle (ie: in the section
4238 * between rcu_idle_enter() and rcu_idle_exit(), then RCU
4239 * considers that CPU to be in an "extended quiescent state",
4240 * which means that RCU will be completely ignoring that CPU.
4241 * Therefore, rcu_read_lock() and friends have absolutely no
4242 * effect on a CPU running in that state. In other words, even if
4243 * such an RCU-idle CPU has called rcu_read_lock(), RCU might well
4244 * delete data structures out from under it. RCU really has no
4245 * choice here: we need to keep an RCU-free window in idle where
4246 * the CPU may possibly enter into low power mode. This way we can
4247 * notice an extended quiescent state to other CPUs that started a grace
4248 * period. Otherwise we would delay any grace period as long as we run
4249 * in the idle task.
4250 *
4251 * So complain bitterly if someone does call rcu_read_lock(),
4252 * rcu_read_lock_bh() and so on from extended quiescent states.
4253 */
Paul E. McKenney5c173eb2013-09-13 17:20:11 -07004254 if (!rcu_is_watching())
Frederic Weisbecker0464e932011-10-07 18:22:01 +02004255 printk("RCU used illegally from extended quiescent state!\n");
4256
Paul E. McKenney0632eb32010-02-22 17:04:47 -08004257 lockdep_print_held_locks(curr);
4258 printk("\nstack backtrace:\n");
4259 dump_stack();
4260}
Paul E. McKenneyb3fbab02011-05-24 08:31:09 -07004261EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);