Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1 | /* |
| 2 | * kernel/lockdep.c |
| 3 | * |
| 4 | * Runtime locking correctness validator |
| 5 | * |
| 6 | * Started by Ingo Molnar: |
| 7 | * |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 8 | * Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
| 9 | * Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com> |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 10 | * |
| 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 Rostedt | a5e2588 | 2008-12-02 15:34:05 -0500 | [diff] [blame] | 28 | #define DISABLE_BRANCH_PROFILING |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 29 | #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 Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 41 | #include <linux/utsname.h> |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 42 | #include <linux/hash.h> |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 43 | #include <linux/ftrace.h> |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 44 | #include <linux/stringify.h> |
Ming Lei | d588e46 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 45 | #include <linux/bitops.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 46 | #include <linux/gfp.h> |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 47 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 48 | #include <asm/sections.h> |
| 49 | |
| 50 | #include "lockdep_internals.h" |
| 51 | |
Steven Rostedt | a8d154b | 2009-04-10 09:36:00 -0400 | [diff] [blame] | 52 | #define CREATE_TRACE_POINTS |
Frederic Weisbecker | 6717876 | 2009-11-13 10:06:34 +0100 | [diff] [blame] | 53 | #include <trace/events/lock.h> |
Steven Rostedt | a8d154b | 2009-04-10 09:36:00 -0400 | [diff] [blame] | 54 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 55 | #ifdef CONFIG_PROVE_LOCKING |
| 56 | int prove_locking = 1; |
| 57 | module_param(prove_locking, int, 0644); |
| 58 | #else |
| 59 | #define prove_locking 0 |
| 60 | #endif |
| 61 | |
| 62 | #ifdef CONFIG_LOCK_STAT |
| 63 | int lock_stat = 1; |
| 64 | module_param(lock_stat, int, 0644); |
| 65 | #else |
| 66 | #define lock_stat 0 |
| 67 | #endif |
| 68 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 69 | /* |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 70 | * lockdep_lock: protects the lockdep graph, the hashes and the |
| 71 | * class/list/hash allocators. |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 72 | * |
| 73 | * This is one of the rare exceptions where it's justified |
| 74 | * to use a raw spinlock - we really dont want the spinlock |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 75 | * code to recurse back into the lockdep code... |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 76 | */ |
Thomas Gleixner | edc35bd | 2009-12-03 12:38:57 +0100 | [diff] [blame] | 77 | static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 78 | |
| 79 | static int graph_lock(void) |
| 80 | { |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 81 | arch_spin_lock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 82 | /* |
| 83 | * Make sure that if another CPU detected a bug while |
| 84 | * walking the graph we dont change it (while the other |
| 85 | * CPU is busy printing out stuff with the graph lock |
| 86 | * dropped already) |
| 87 | */ |
| 88 | if (!debug_locks) { |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 89 | arch_spin_unlock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 90 | return 0; |
| 91 | } |
Steven Rostedt | bb065af | 2008-05-12 21:21:00 +0200 | [diff] [blame] | 92 | /* prevent any recursions within lockdep from causing deadlocks */ |
| 93 | current->lockdep_recursion++; |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 94 | return 1; |
| 95 | } |
| 96 | |
| 97 | static inline int graph_unlock(void) |
| 98 | { |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 99 | if (debug_locks && !arch_spin_is_locked(&lockdep_lock)) |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 100 | return DEBUG_LOCKS_WARN_ON(1); |
| 101 | |
Steven Rostedt | bb065af | 2008-05-12 21:21:00 +0200 | [diff] [blame] | 102 | current->lockdep_recursion--; |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 103 | arch_spin_unlock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 104 | return 0; |
| 105 | } |
| 106 | |
| 107 | /* |
| 108 | * Turn lock debugging off and return with 0 if it was off already, |
| 109 | * and also release the graph lock: |
| 110 | */ |
| 111 | static inline int debug_locks_off_graph_unlock(void) |
| 112 | { |
| 113 | int ret = debug_locks_off(); |
| 114 | |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 115 | arch_spin_unlock(&lockdep_lock); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 116 | |
| 117 | return ret; |
| 118 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 119 | |
| 120 | static int lockdep_initialized; |
| 121 | |
| 122 | unsigned long nr_list_entries; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 123 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 124 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 125 | /* |
| 126 | * All data structures here are protected by the global debug_lock. |
| 127 | * |
| 128 | * Mutex key structs only get allocated, once during bootup, and never |
| 129 | * get freed - this significantly simplifies the debugging code. |
| 130 | */ |
| 131 | unsigned long nr_lock_classes; |
| 132 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; |
| 133 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 134 | static inline struct lock_class *hlock_class(struct held_lock *hlock) |
| 135 | { |
| 136 | if (!hlock->class_idx) { |
| 137 | DEBUG_LOCKS_WARN_ON(1); |
| 138 | return NULL; |
| 139 | } |
| 140 | return lock_classes + hlock->class_idx - 1; |
| 141 | } |
| 142 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 143 | #ifdef CONFIG_LOCK_STAT |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 144 | static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], |
| 145 | cpu_lock_stats); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 146 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 147 | static inline u64 lockstat_clock(void) |
| 148 | { |
Peter Zijlstra | c676329 | 2010-05-25 10:48:51 +0200 | [diff] [blame] | 149 | return local_clock(); |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 150 | } |
| 151 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 152 | static int lock_point(unsigned long points[], unsigned long ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 153 | { |
| 154 | int i; |
| 155 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 156 | for (i = 0; i < LOCKSTAT_POINTS; i++) { |
| 157 | if (points[i] == 0) { |
| 158 | points[i] = ip; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 159 | break; |
| 160 | } |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 161 | if (points[i] == ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 162 | break; |
| 163 | } |
| 164 | |
| 165 | return i; |
| 166 | } |
| 167 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 168 | static void lock_time_inc(struct lock_time *lt, u64 time) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 169 | { |
| 170 | if (time > lt->max) |
| 171 | lt->max = time; |
| 172 | |
Frank Rowand | 109d71c | 2009-11-19 13:42:06 -0800 | [diff] [blame] | 173 | if (time < lt->min || !lt->nr) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 174 | lt->min = time; |
| 175 | |
| 176 | lt->total += time; |
| 177 | lt->nr++; |
| 178 | } |
| 179 | |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 180 | static inline void lock_time_add(struct lock_time *src, struct lock_time *dst) |
| 181 | { |
Frank Rowand | 109d71c | 2009-11-19 13:42:06 -0800 | [diff] [blame] | 182 | if (!src->nr) |
| 183 | return; |
| 184 | |
| 185 | if (src->max > dst->max) |
| 186 | dst->max = src->max; |
| 187 | |
| 188 | if (src->min < dst->min || !dst->nr) |
| 189 | dst->min = src->min; |
| 190 | |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 191 | dst->total += src->total; |
| 192 | dst->nr += src->nr; |
| 193 | } |
| 194 | |
| 195 | struct lock_class_stats lock_stats(struct lock_class *class) |
| 196 | { |
| 197 | struct lock_class_stats stats; |
| 198 | int cpu, i; |
| 199 | |
| 200 | memset(&stats, 0, sizeof(struct lock_class_stats)); |
| 201 | for_each_possible_cpu(cpu) { |
| 202 | struct lock_class_stats *pcs = |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 203 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 204 | |
| 205 | for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++) |
| 206 | stats.contention_point[i] += pcs->contention_point[i]; |
| 207 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 208 | for (i = 0; i < ARRAY_SIZE(stats.contending_point); i++) |
| 209 | stats.contending_point[i] += pcs->contending_point[i]; |
| 210 | |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 211 | lock_time_add(&pcs->read_waittime, &stats.read_waittime); |
| 212 | lock_time_add(&pcs->write_waittime, &stats.write_waittime); |
| 213 | |
| 214 | lock_time_add(&pcs->read_holdtime, &stats.read_holdtime); |
| 215 | lock_time_add(&pcs->write_holdtime, &stats.write_holdtime); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 216 | |
| 217 | for (i = 0; i < ARRAY_SIZE(stats.bounces); i++) |
| 218 | stats.bounces[i] += pcs->bounces[i]; |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 219 | } |
| 220 | |
| 221 | return stats; |
| 222 | } |
| 223 | |
| 224 | void clear_lock_stats(struct lock_class *class) |
| 225 | { |
| 226 | int cpu; |
| 227 | |
| 228 | for_each_possible_cpu(cpu) { |
| 229 | struct lock_class_stats *cpu_stats = |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 230 | &per_cpu(cpu_lock_stats, cpu)[class - lock_classes]; |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 231 | |
| 232 | memset(cpu_stats, 0, sizeof(struct lock_class_stats)); |
| 233 | } |
| 234 | memset(class->contention_point, 0, sizeof(class->contention_point)); |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 235 | memset(class->contending_point, 0, sizeof(class->contending_point)); |
Peter Zijlstra | c46261d | 2007-07-19 01:48:57 -0700 | [diff] [blame] | 236 | } |
| 237 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 238 | static struct lock_class_stats *get_lock_stats(struct lock_class *class) |
| 239 | { |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 240 | return &get_cpu_var(cpu_lock_stats)[class - lock_classes]; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 241 | } |
| 242 | |
| 243 | static void put_lock_stats(struct lock_class_stats *stats) |
| 244 | { |
Tejun Heo | 1871e52 | 2009-10-29 22:34:13 +0900 | [diff] [blame] | 245 | put_cpu_var(cpu_lock_stats); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 246 | } |
| 247 | |
| 248 | static void lock_release_holdtime(struct held_lock *hlock) |
| 249 | { |
| 250 | struct lock_class_stats *stats; |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 251 | u64 holdtime; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 252 | |
| 253 | if (!lock_stat) |
| 254 | return; |
| 255 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 256 | holdtime = lockstat_clock() - hlock->holdtime_stamp; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 257 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 258 | stats = get_lock_stats(hlock_class(hlock)); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 259 | if (hlock->read) |
| 260 | lock_time_inc(&stats->read_holdtime, holdtime); |
| 261 | else |
| 262 | lock_time_inc(&stats->write_holdtime, holdtime); |
| 263 | put_lock_stats(stats); |
| 264 | } |
| 265 | #else |
| 266 | static inline void lock_release_holdtime(struct held_lock *hlock) |
| 267 | { |
| 268 | } |
| 269 | #endif |
| 270 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 271 | /* |
| 272 | * We keep a global list of all lock classes. The list only grows, |
| 273 | * never shrinks. The list is only accessed with the lockdep |
| 274 | * spinlock lock held. |
| 275 | */ |
| 276 | LIST_HEAD(all_lock_classes); |
| 277 | |
| 278 | /* |
| 279 | * The lockdep classes are in a hash-table as well, for fast lookup: |
| 280 | */ |
| 281 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) |
| 282 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 283 | #define __classhashfn(key) hash_long((unsigned long)key, CLASSHASH_BITS) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 284 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
| 285 | |
| 286 | static struct list_head classhash_table[CLASSHASH_SIZE]; |
| 287 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 288 | /* |
| 289 | * We put the lock dependency chains into a hash-table as well, to cache |
| 290 | * their existence: |
| 291 | */ |
| 292 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) |
| 293 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 294 | #define __chainhashfn(chain) hash_long(chain, CHAINHASH_BITS) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 295 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
| 296 | |
| 297 | static struct list_head chainhash_table[CHAINHASH_SIZE]; |
| 298 | |
| 299 | /* |
| 300 | * The hash key of the lock dependency chains is a hash itself too: |
| 301 | * it's a hash of all locks taken up to that lock, including that lock. |
| 302 | * It's a 64-bit hash, because it's important for the keys to be |
| 303 | * unique. |
| 304 | */ |
| 305 | #define iterate_chain_key(key1, key2) \ |
Ingo Molnar | 03cbc35 | 2006-09-29 02:01:46 -0700 | [diff] [blame] | 306 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
| 307 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 308 | (key2)) |
| 309 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 310 | void lockdep_off(void) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 311 | { |
| 312 | current->lockdep_recursion++; |
| 313 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 314 | EXPORT_SYMBOL(lockdep_off); |
| 315 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 316 | void lockdep_on(void) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 317 | { |
| 318 | current->lockdep_recursion--; |
| 319 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 320 | EXPORT_SYMBOL(lockdep_on); |
| 321 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 322 | /* |
| 323 | * Debugging switches: |
| 324 | */ |
| 325 | |
| 326 | #define VERBOSE 0 |
Ingo Molnar | 33e94e9 | 2006-12-13 00:34:41 -0800 | [diff] [blame] | 327 | #define VERY_VERBOSE 0 |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 328 | |
| 329 | #if VERBOSE |
| 330 | # define HARDIRQ_VERBOSE 1 |
| 331 | # define SOFTIRQ_VERBOSE 1 |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 332 | # define RECLAIM_VERBOSE 1 |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 333 | #else |
| 334 | # define HARDIRQ_VERBOSE 0 |
| 335 | # define SOFTIRQ_VERBOSE 0 |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 336 | # define RECLAIM_VERBOSE 0 |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 337 | #endif |
| 338 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 339 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE || RECLAIM_VERBOSE |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 340 | /* |
| 341 | * Quick filtering for interesting events: |
| 342 | */ |
| 343 | static int class_filter(struct lock_class *class) |
| 344 | { |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 345 | #if 0 |
| 346 | /* Example */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 347 | if (class->name_version == 1 && |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 348 | !strcmp(class->name, "lockname")) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 349 | return 1; |
| 350 | if (class->name_version == 1 && |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 351 | !strcmp(class->name, "&struct->lockfield")) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 352 | return 1; |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 353 | #endif |
Ingo Molnar | a664089 | 2006-12-13 00:34:39 -0800 | [diff] [blame] | 354 | /* Filter everything else. 1 would be to allow everything else */ |
| 355 | return 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 356 | } |
| 357 | #endif |
| 358 | |
| 359 | static int verbose(struct lock_class *class) |
| 360 | { |
| 361 | #if VERBOSE |
| 362 | return class_filter(class); |
| 363 | #endif |
| 364 | return 0; |
| 365 | } |
| 366 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 367 | /* |
| 368 | * Stack-trace: tightly packed array of stack backtrace |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 369 | * addresses. Protected by the graph_lock. |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 370 | */ |
| 371 | unsigned long nr_stack_trace_entries; |
| 372 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; |
| 373 | |
| 374 | static int save_trace(struct stack_trace *trace) |
| 375 | { |
| 376 | trace->nr_entries = 0; |
| 377 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; |
| 378 | trace->entries = stack_trace + nr_stack_trace_entries; |
| 379 | |
Andi Kleen | 5a1b399 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 380 | trace->skip = 3; |
Andi Kleen | 5a1b399 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 381 | |
Christoph Hellwig | ab1b6f0 | 2007-05-08 00:23:29 -0700 | [diff] [blame] | 382 | save_stack_trace(trace); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 383 | |
Peter Zijlstra | 4f84f43 | 2009-07-20 15:27:04 +0200 | [diff] [blame] | 384 | /* |
| 385 | * Some daft arches put -1 at the end to indicate its a full trace. |
| 386 | * |
| 387 | * <rant> this is buggy anyway, since it takes a whole extra entry so a |
| 388 | * complete trace that maxes out the entries provided will be reported |
| 389 | * as incomplete, friggin useless </rant> |
| 390 | */ |
Luck, Tony | ea5b41f | 2009-12-09 14:29:36 -0800 | [diff] [blame] | 391 | if (trace->nr_entries != 0 && |
| 392 | trace->entries[trace->nr_entries-1] == ULONG_MAX) |
Peter Zijlstra | 4f84f43 | 2009-07-20 15:27:04 +0200 | [diff] [blame] | 393 | trace->nr_entries--; |
| 394 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 395 | trace->max_entries = trace->nr_entries; |
| 396 | |
| 397 | nr_stack_trace_entries += trace->nr_entries; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 398 | |
Peter Zijlstra | 4f84f43 | 2009-07-20 15:27:04 +0200 | [diff] [blame] | 399 | if (nr_stack_trace_entries >= MAX_STACK_TRACE_ENTRIES-1) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 400 | if (!debug_locks_off_graph_unlock()) |
| 401 | return 0; |
| 402 | |
| 403 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); |
| 404 | printk("turning off the locking correctness validator.\n"); |
| 405 | dump_stack(); |
| 406 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 407 | return 0; |
| 408 | } |
| 409 | |
| 410 | return 1; |
| 411 | } |
| 412 | |
| 413 | unsigned int nr_hardirq_chains; |
| 414 | unsigned int nr_softirq_chains; |
| 415 | unsigned int nr_process_chains; |
| 416 | unsigned int max_lockdep_depth; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 417 | |
| 418 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 419 | /* |
| 420 | * We cannot printk in early bootup code. Not even early_printk() |
| 421 | * might work. So we mark any initialization errors and printk |
| 422 | * about it later on, in lockdep_info(). |
| 423 | */ |
| 424 | static int lockdep_init_error; |
Johannes Berg | c71063c | 2007-07-19 01:49:02 -0700 | [diff] [blame] | 425 | static unsigned long lockdep_init_trace_data[20]; |
| 426 | static struct stack_trace lockdep_init_trace = { |
| 427 | .max_entries = ARRAY_SIZE(lockdep_init_trace_data), |
| 428 | .entries = lockdep_init_trace_data, |
| 429 | }; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 430 | |
| 431 | /* |
| 432 | * Various lockdep statistics: |
| 433 | */ |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 434 | DEFINE_PER_CPU(struct lockdep_stats, lockdep_stats); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 435 | #endif |
| 436 | |
| 437 | /* |
| 438 | * Locking printouts: |
| 439 | */ |
| 440 | |
Peter Zijlstra | fabe9c4 | 2009-01-22 14:51:01 +0100 | [diff] [blame] | 441 | #define __USAGE(__STATE) \ |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 442 | [LOCK_USED_IN_##__STATE] = "IN-"__stringify(__STATE)"-W", \ |
| 443 | [LOCK_ENABLED_##__STATE] = __stringify(__STATE)"-ON-W", \ |
| 444 | [LOCK_USED_IN_##__STATE##_READ] = "IN-"__stringify(__STATE)"-R",\ |
| 445 | [LOCK_ENABLED_##__STATE##_READ] = __stringify(__STATE)"-ON-R", |
Peter Zijlstra | fabe9c4 | 2009-01-22 14:51:01 +0100 | [diff] [blame] | 446 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 447 | static const char *usage_str[] = |
| 448 | { |
Peter Zijlstra | fabe9c4 | 2009-01-22 14:51:01 +0100 | [diff] [blame] | 449 | #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) |
| 450 | #include "lockdep_states.h" |
| 451 | #undef LOCKDEP_STATE |
| 452 | [LOCK_USED] = "INITIAL USE", |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 453 | }; |
| 454 | |
| 455 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) |
| 456 | { |
Alexey Dobriyan | ffb4512 | 2007-05-08 00:28:41 -0700 | [diff] [blame] | 457 | return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 458 | } |
| 459 | |
Peter Zijlstra | 3ff176c | 2009-01-22 17:40:42 +0100 | [diff] [blame] | 460 | static inline unsigned long lock_flag(enum lock_usage_bit bit) |
| 461 | { |
| 462 | return 1UL << bit; |
| 463 | } |
| 464 | |
| 465 | static char get_usage_char(struct lock_class *class, enum lock_usage_bit bit) |
| 466 | { |
| 467 | char c = '.'; |
| 468 | |
| 469 | if (class->usage_mask & lock_flag(bit + 2)) |
| 470 | c = '+'; |
| 471 | if (class->usage_mask & lock_flag(bit)) { |
| 472 | c = '-'; |
| 473 | if (class->usage_mask & lock_flag(bit + 2)) |
| 474 | c = '?'; |
| 475 | } |
| 476 | |
| 477 | return c; |
| 478 | } |
| 479 | |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 480 | void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS]) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 481 | { |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 482 | int i = 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 483 | |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 484 | #define LOCKDEP_STATE(__STATE) \ |
| 485 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE); \ |
| 486 | usage[i++] = get_usage_char(class, LOCK_USED_IN_##__STATE##_READ); |
| 487 | #include "lockdep_states.h" |
| 488 | #undef LOCKDEP_STATE |
| 489 | |
| 490 | usage[i] = '\0'; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 491 | } |
| 492 | |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 493 | static int __print_lock_name(struct lock_class *class) |
| 494 | { |
| 495 | char str[KSYM_NAME_LEN]; |
| 496 | const char *name; |
| 497 | |
| 498 | name = class->name; |
| 499 | if (!name) |
| 500 | name = __get_key_name(class->key, str); |
| 501 | |
| 502 | return printk("%s", name); |
| 503 | } |
| 504 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 505 | static void print_lock_name(struct lock_class *class) |
| 506 | { |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 507 | char str[KSYM_NAME_LEN], usage[LOCK_USAGE_CHARS]; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 508 | const char *name; |
| 509 | |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 510 | get_usage_chars(class, usage); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 511 | |
| 512 | name = class->name; |
| 513 | if (!name) { |
| 514 | name = __get_key_name(class->key, str); |
| 515 | printk(" (%s", name); |
| 516 | } else { |
| 517 | printk(" (%s", name); |
| 518 | if (class->name_version > 1) |
| 519 | printk("#%d", class->name_version); |
| 520 | if (class->subclass) |
| 521 | printk("/%d", class->subclass); |
| 522 | } |
Peter Zijlstra | f510b23 | 2009-01-22 17:53:47 +0100 | [diff] [blame] | 523 | printk("){%s}", usage); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 524 | } |
| 525 | |
| 526 | static void print_lockdep_cache(struct lockdep_map *lock) |
| 527 | { |
| 528 | const char *name; |
Tejun Heo | 9281ace | 2007-07-17 04:03:51 -0700 | [diff] [blame] | 529 | char str[KSYM_NAME_LEN]; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 530 | |
| 531 | name = lock->name; |
| 532 | if (!name) |
| 533 | name = __get_key_name(lock->key->subkeys, str); |
| 534 | |
| 535 | printk("%s", name); |
| 536 | } |
| 537 | |
| 538 | static void print_lock(struct held_lock *hlock) |
| 539 | { |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 540 | print_lock_name(hlock_class(hlock)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 541 | printk(", at: "); |
| 542 | print_ip_sym(hlock->acquire_ip); |
| 543 | } |
| 544 | |
| 545 | static void lockdep_print_held_locks(struct task_struct *curr) |
| 546 | { |
| 547 | int i, depth = curr->lockdep_depth; |
| 548 | |
| 549 | if (!depth) { |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 550 | printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 551 | return; |
| 552 | } |
| 553 | printk("%d lock%s held by %s/%d:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 554 | depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 555 | |
| 556 | for (i = 0; i < depth; i++) { |
| 557 | printk(" #%d: ", i); |
| 558 | print_lock(curr->held_locks + i); |
| 559 | } |
| 560 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 561 | |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 562 | static void print_kernel_version(void) |
| 563 | { |
Serge E. Hallyn | 96b644b | 2006-10-02 02:18:13 -0700 | [diff] [blame] | 564 | printk("%s %.*s\n", init_utsname()->release, |
| 565 | (int)strcspn(init_utsname()->version, " "), |
| 566 | init_utsname()->version); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 567 | } |
| 568 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 569 | static int very_verbose(struct lock_class *class) |
| 570 | { |
| 571 | #if VERY_VERBOSE |
| 572 | return class_filter(class); |
| 573 | #endif |
| 574 | return 0; |
| 575 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 576 | |
| 577 | /* |
| 578 | * Is this the address of a static object: |
| 579 | */ |
| 580 | static int static_obj(void *obj) |
| 581 | { |
| 582 | unsigned long start = (unsigned long) &_stext, |
| 583 | end = (unsigned long) &_end, |
| 584 | addr = (unsigned long) obj; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 585 | |
| 586 | /* |
| 587 | * static variable? |
| 588 | */ |
| 589 | if ((addr >= start) && (addr < end)) |
| 590 | return 1; |
| 591 | |
Mike Frysinger | 2a9ad18 | 2009-09-22 16:44:16 -0700 | [diff] [blame] | 592 | if (arch_is_kernel_data(addr)) |
| 593 | return 1; |
| 594 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 595 | /* |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 596 | * in-kernel percpu var? |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 597 | */ |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 598 | if (is_kernel_percpu_address(addr)) |
| 599 | return 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 600 | |
| 601 | /* |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 602 | * module static or percpu var? |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 603 | */ |
Tejun Heo | 10fad5e | 2010-03-10 18:57:54 +0900 | [diff] [blame] | 604 | return is_module_address(addr) || is_module_percpu_address(addr); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 605 | } |
| 606 | |
| 607 | /* |
| 608 | * To make lock name printouts unique, we calculate a unique |
| 609 | * class->name_version generation counter: |
| 610 | */ |
| 611 | static int count_matching_names(struct lock_class *new_class) |
| 612 | { |
| 613 | struct lock_class *class; |
| 614 | int count = 0; |
| 615 | |
| 616 | if (!new_class->name) |
| 617 | return 0; |
| 618 | |
| 619 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
| 620 | if (new_class->key - new_class->subclass == class->key) |
| 621 | return class->name_version; |
| 622 | if (class->name && !strcmp(class->name, new_class->name)) |
| 623 | count = max(count, class->name_version); |
| 624 | } |
| 625 | |
| 626 | return count + 1; |
| 627 | } |
| 628 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 629 | /* |
| 630 | * Register a lock's class in the hash-table, if the class is not present |
| 631 | * yet. Otherwise we look it up. We cache the result in the lock object |
| 632 | * itself, so actual lookup of the hash should be once per lock object. |
| 633 | */ |
| 634 | static inline struct lock_class * |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 635 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 636 | { |
| 637 | struct lockdep_subclass_key *key; |
| 638 | struct list_head *hash_head; |
| 639 | struct lock_class *class; |
| 640 | |
| 641 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 642 | /* |
| 643 | * If the architecture calls into lockdep before initializing |
| 644 | * the hashes then we'll warn about it later. (we cannot printk |
| 645 | * right now) |
| 646 | */ |
| 647 | if (unlikely(!lockdep_initialized)) { |
| 648 | lockdep_init(); |
| 649 | lockdep_init_error = 1; |
Johannes Berg | c71063c | 2007-07-19 01:49:02 -0700 | [diff] [blame] | 650 | save_stack_trace(&lockdep_init_trace); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 651 | } |
| 652 | #endif |
| 653 | |
Hitoshi Mitake | 4ba053c | 2010-10-13 17:30:26 +0900 | [diff] [blame] | 654 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
| 655 | debug_locks_off(); |
| 656 | printk(KERN_ERR |
| 657 | "BUG: looking up invalid subclass: %u\n", subclass); |
| 658 | printk(KERN_ERR |
| 659 | "turning off the locking correctness validator.\n"); |
| 660 | dump_stack(); |
| 661 | return NULL; |
| 662 | } |
| 663 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 664 | /* |
| 665 | * Static locks do not have their class-keys yet - for them the key |
| 666 | * is the lock object itself: |
| 667 | */ |
| 668 | if (unlikely(!lock->key)) |
| 669 | lock->key = (void *)lock; |
| 670 | |
| 671 | /* |
| 672 | * NOTE: the class-key must be unique. For dynamic locks, a static |
| 673 | * lock_class_key variable is passed in through the mutex_init() |
| 674 | * (or spin_lock_init()) call - which acts as the key. For static |
| 675 | * locks we use the lock object itself as the key. |
| 676 | */ |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 677 | BUILD_BUG_ON(sizeof(struct lock_class_key) > |
| 678 | sizeof(struct lockdep_map)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 679 | |
| 680 | key = lock->key->subkeys + subclass; |
| 681 | |
| 682 | hash_head = classhashentry(key); |
| 683 | |
| 684 | /* |
| 685 | * We can walk the hash lockfree, because the hash only |
| 686 | * grows, and we are careful when adding entries to the end: |
| 687 | */ |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 688 | list_for_each_entry(class, hash_head, hash_entry) { |
| 689 | if (class->key == key) { |
| 690 | WARN_ON_ONCE(class->name != lock->name); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 691 | return class; |
Peter Zijlstra | 4b32d0a | 2007-07-19 01:48:59 -0700 | [diff] [blame] | 692 | } |
| 693 | } |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 694 | |
| 695 | return NULL; |
| 696 | } |
| 697 | |
| 698 | /* |
| 699 | * Register a lock's class in the hash-table, if the class is not present |
| 700 | * yet. Otherwise we look it up. We cache the result in the lock object |
| 701 | * itself, so actual lookup of the hash should be once per lock object. |
| 702 | */ |
| 703 | static inline struct lock_class * |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 704 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 705 | { |
| 706 | struct lockdep_subclass_key *key; |
| 707 | struct list_head *hash_head; |
| 708 | struct lock_class *class; |
Ingo Molnar | 70e4506 | 2006-12-06 20:40:50 -0800 | [diff] [blame] | 709 | unsigned long flags; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 710 | |
| 711 | class = look_up_lock_class(lock, subclass); |
| 712 | if (likely(class)) |
| 713 | return class; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 714 | |
| 715 | /* |
| 716 | * Debug-check: all keys must be persistent! |
| 717 | */ |
| 718 | if (!static_obj(lock->key)) { |
| 719 | debug_locks_off(); |
| 720 | printk("INFO: trying to register non-static key.\n"); |
| 721 | printk("the code is fine but needs lockdep annotation.\n"); |
| 722 | printk("turning off the locking correctness validator.\n"); |
| 723 | dump_stack(); |
| 724 | |
| 725 | return NULL; |
| 726 | } |
| 727 | |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 728 | key = lock->key->subkeys + subclass; |
| 729 | hash_head = classhashentry(key); |
| 730 | |
Ingo Molnar | 70e4506 | 2006-12-06 20:40:50 -0800 | [diff] [blame] | 731 | raw_local_irq_save(flags); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 732 | if (!graph_lock()) { |
| 733 | raw_local_irq_restore(flags); |
| 734 | return NULL; |
| 735 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 736 | /* |
| 737 | * We have to do the hash-walk again, to avoid races |
| 738 | * with another CPU: |
| 739 | */ |
| 740 | list_for_each_entry(class, hash_head, hash_entry) |
| 741 | if (class->key == key) |
| 742 | goto out_unlock_set; |
| 743 | /* |
| 744 | * Allocate a new key from the static array, and add it to |
| 745 | * the hash: |
| 746 | */ |
| 747 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 748 | if (!debug_locks_off_graph_unlock()) { |
| 749 | raw_local_irq_restore(flags); |
| 750 | return NULL; |
| 751 | } |
Ingo Molnar | 70e4506 | 2006-12-06 20:40:50 -0800 | [diff] [blame] | 752 | raw_local_irq_restore(flags); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 753 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 754 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); |
| 755 | printk("turning off the locking correctness validator.\n"); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 756 | dump_stack(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 757 | return NULL; |
| 758 | } |
| 759 | class = lock_classes + nr_lock_classes++; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 760 | debug_atomic_inc(nr_unused_locks); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 761 | class->key = key; |
| 762 | class->name = lock->name; |
| 763 | class->subclass = subclass; |
| 764 | INIT_LIST_HEAD(&class->lock_entry); |
| 765 | INIT_LIST_HEAD(&class->locks_before); |
| 766 | INIT_LIST_HEAD(&class->locks_after); |
| 767 | class->name_version = count_matching_names(class); |
| 768 | /* |
| 769 | * We use RCU's safe list-add method to make |
| 770 | * parallel walking of the hash-list safe: |
| 771 | */ |
| 772 | list_add_tail_rcu(&class->hash_entry, hash_head); |
Dale Farnsworth | 1481197 | 2008-02-25 23:03:02 +0100 | [diff] [blame] | 773 | /* |
| 774 | * Add it to the global list of classes: |
| 775 | */ |
| 776 | list_add_tail_rcu(&class->lock_entry, &all_lock_classes); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 777 | |
| 778 | if (verbose(class)) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 779 | graph_unlock(); |
Ingo Molnar | 70e4506 | 2006-12-06 20:40:50 -0800 | [diff] [blame] | 780 | raw_local_irq_restore(flags); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 781 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 782 | printk("\nnew class %p: %s", class->key, class->name); |
| 783 | if (class->name_version > 1) |
| 784 | printk("#%d", class->name_version); |
| 785 | printk("\n"); |
| 786 | dump_stack(); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 787 | |
Ingo Molnar | 70e4506 | 2006-12-06 20:40:50 -0800 | [diff] [blame] | 788 | raw_local_irq_save(flags); |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 789 | if (!graph_lock()) { |
| 790 | raw_local_irq_restore(flags); |
| 791 | return NULL; |
| 792 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 793 | } |
| 794 | out_unlock_set: |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 795 | graph_unlock(); |
Ingo Molnar | 70e4506 | 2006-12-06 20:40:50 -0800 | [diff] [blame] | 796 | raw_local_irq_restore(flags); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 797 | |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 798 | if (!subclass || force) |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 799 | lock->class_cache[0] = class; |
| 800 | else if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
| 801 | lock->class_cache[subclass] = class; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 802 | |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 803 | if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass)) |
| 804 | return NULL; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 805 | |
| 806 | return class; |
| 807 | } |
| 808 | |
Peter Zijlstra | ca58abc | 2007-07-19 01:48:53 -0700 | [diff] [blame] | 809 | #ifdef CONFIG_PROVE_LOCKING |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 810 | /* |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 811 | * Allocate a lockdep entry. (assumes the graph_lock held, returns |
| 812 | * with NULL on failure) |
| 813 | */ |
| 814 | static struct lock_list *alloc_list_entry(void) |
| 815 | { |
| 816 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { |
| 817 | if (!debug_locks_off_graph_unlock()) |
| 818 | return NULL; |
| 819 | |
| 820 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); |
| 821 | printk("turning off the locking correctness validator.\n"); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 822 | dump_stack(); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 823 | return NULL; |
| 824 | } |
| 825 | return list_entries + nr_list_entries++; |
| 826 | } |
| 827 | |
| 828 | /* |
| 829 | * Add a new dependency to the head of the list: |
| 830 | */ |
| 831 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 832 | struct list_head *head, unsigned long ip, |
| 833 | int distance, struct stack_trace *trace) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 834 | { |
| 835 | struct lock_list *entry; |
| 836 | /* |
| 837 | * Lock not present yet - get a new dependency struct and |
| 838 | * add it to the list: |
| 839 | */ |
| 840 | entry = alloc_list_entry(); |
| 841 | if (!entry) |
| 842 | return 0; |
| 843 | |
Zhu Yi | 7487017 | 2008-08-27 14:33:00 +0800 | [diff] [blame] | 844 | entry->class = this; |
| 845 | entry->distance = distance; |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 846 | entry->trace = *trace; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 847 | /* |
| 848 | * Since we never remove from the dependency list, the list can |
| 849 | * be walked lockless by other CPUs, it's only allocation |
| 850 | * that must be protected by the spinlock. But this also means |
| 851 | * we must make new entries visible only once writes to the |
| 852 | * entry become visible - hence the RCU op: |
| 853 | */ |
| 854 | list_add_tail_rcu(&entry->entry, head); |
| 855 | |
| 856 | return 1; |
| 857 | } |
| 858 | |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 859 | /* |
| 860 | * For good efficiency of modular, we use power of 2 |
| 861 | */ |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 862 | #define MAX_CIRCULAR_QUEUE_SIZE 4096UL |
| 863 | #define CQ_MASK (MAX_CIRCULAR_QUEUE_SIZE-1) |
| 864 | |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 865 | /* |
| 866 | * The circular_queue and helpers is used to implement the |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 867 | * breadth-first search(BFS)algorithem, by which we can build |
| 868 | * the shortest path from the next lock to be acquired to the |
| 869 | * previous held lock if there is a circular between them. |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 870 | */ |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 871 | struct circular_queue { |
| 872 | unsigned long element[MAX_CIRCULAR_QUEUE_SIZE]; |
| 873 | unsigned int front, rear; |
| 874 | }; |
| 875 | |
| 876 | static struct circular_queue lock_cq; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 877 | |
Ming Lei | 12f3dfd | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 878 | unsigned int max_bfs_queue_depth; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 879 | |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 880 | static unsigned int lockdep_dependency_gen_id; |
| 881 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 882 | static inline void __cq_init(struct circular_queue *cq) |
| 883 | { |
| 884 | cq->front = cq->rear = 0; |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 885 | lockdep_dependency_gen_id++; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 886 | } |
| 887 | |
| 888 | static inline int __cq_empty(struct circular_queue *cq) |
| 889 | { |
| 890 | return (cq->front == cq->rear); |
| 891 | } |
| 892 | |
| 893 | static inline int __cq_full(struct circular_queue *cq) |
| 894 | { |
| 895 | return ((cq->rear + 1) & CQ_MASK) == cq->front; |
| 896 | } |
| 897 | |
| 898 | static inline int __cq_enqueue(struct circular_queue *cq, unsigned long elem) |
| 899 | { |
| 900 | if (__cq_full(cq)) |
| 901 | return -1; |
| 902 | |
| 903 | cq->element[cq->rear] = elem; |
| 904 | cq->rear = (cq->rear + 1) & CQ_MASK; |
| 905 | return 0; |
| 906 | } |
| 907 | |
| 908 | static inline int __cq_dequeue(struct circular_queue *cq, unsigned long *elem) |
| 909 | { |
| 910 | if (__cq_empty(cq)) |
| 911 | return -1; |
| 912 | |
| 913 | *elem = cq->element[cq->front]; |
| 914 | cq->front = (cq->front + 1) & CQ_MASK; |
| 915 | return 0; |
| 916 | } |
| 917 | |
| 918 | static inline unsigned int __cq_get_elem_count(struct circular_queue *cq) |
| 919 | { |
| 920 | return (cq->rear - cq->front) & CQ_MASK; |
| 921 | } |
| 922 | |
| 923 | static inline void mark_lock_accessed(struct lock_list *lock, |
| 924 | struct lock_list *parent) |
| 925 | { |
| 926 | unsigned long nr; |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 927 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 928 | nr = lock - list_entries; |
| 929 | WARN_ON(nr >= nr_list_entries); |
| 930 | lock->parent = parent; |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 931 | lock->class->dep_gen_id = lockdep_dependency_gen_id; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 932 | } |
| 933 | |
| 934 | static inline unsigned long lock_accessed(struct lock_list *lock) |
| 935 | { |
| 936 | unsigned long nr; |
Peter Zijlstra | 98c33ed | 2009-07-21 13:19:07 +0200 | [diff] [blame] | 937 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 938 | nr = lock - list_entries; |
| 939 | WARN_ON(nr >= nr_list_entries); |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 940 | return lock->class->dep_gen_id == lockdep_dependency_gen_id; |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 941 | } |
| 942 | |
| 943 | static inline struct lock_list *get_lock_parent(struct lock_list *child) |
| 944 | { |
| 945 | return child->parent; |
| 946 | } |
| 947 | |
| 948 | static inline int get_lock_depth(struct lock_list *child) |
| 949 | { |
| 950 | int depth = 0; |
| 951 | struct lock_list *parent; |
| 952 | |
| 953 | while ((parent = get_lock_parent(child))) { |
| 954 | child = parent; |
| 955 | depth++; |
| 956 | } |
| 957 | return depth; |
| 958 | } |
| 959 | |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 960 | static int __bfs(struct lock_list *source_entry, |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 961 | void *data, |
| 962 | int (*match)(struct lock_list *entry, void *data), |
| 963 | struct lock_list **target_entry, |
| 964 | int forward) |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 965 | { |
| 966 | struct lock_list *entry; |
Ming Lei | d588e46 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 967 | struct list_head *head; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 968 | struct circular_queue *cq = &lock_cq; |
| 969 | int ret = 1; |
| 970 | |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 971 | if (match(source_entry, data)) { |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 972 | *target_entry = source_entry; |
| 973 | ret = 0; |
| 974 | goto exit; |
| 975 | } |
| 976 | |
Ming Lei | d588e46 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 977 | if (forward) |
| 978 | head = &source_entry->class->locks_after; |
| 979 | else |
| 980 | head = &source_entry->class->locks_before; |
| 981 | |
| 982 | if (list_empty(head)) |
| 983 | goto exit; |
| 984 | |
| 985 | __cq_init(cq); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 986 | __cq_enqueue(cq, (unsigned long)source_entry); |
| 987 | |
| 988 | while (!__cq_empty(cq)) { |
| 989 | struct lock_list *lock; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 990 | |
| 991 | __cq_dequeue(cq, (unsigned long *)&lock); |
| 992 | |
| 993 | if (!lock->class) { |
| 994 | ret = -2; |
| 995 | goto exit; |
| 996 | } |
| 997 | |
| 998 | if (forward) |
| 999 | head = &lock->class->locks_after; |
| 1000 | else |
| 1001 | head = &lock->class->locks_before; |
| 1002 | |
| 1003 | list_for_each_entry(entry, head, entry) { |
| 1004 | if (!lock_accessed(entry)) { |
Ming Lei | 12f3dfd | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1005 | unsigned int cq_depth; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1006 | mark_lock_accessed(entry, lock); |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1007 | if (match(entry, data)) { |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1008 | *target_entry = entry; |
| 1009 | ret = 0; |
| 1010 | goto exit; |
| 1011 | } |
| 1012 | |
| 1013 | if (__cq_enqueue(cq, (unsigned long)entry)) { |
| 1014 | ret = -1; |
| 1015 | goto exit; |
| 1016 | } |
Ming Lei | 12f3dfd | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1017 | cq_depth = __cq_get_elem_count(cq); |
| 1018 | if (max_bfs_queue_depth < cq_depth) |
| 1019 | max_bfs_queue_depth = cq_depth; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1020 | } |
| 1021 | } |
| 1022 | } |
| 1023 | exit: |
| 1024 | return ret; |
| 1025 | } |
| 1026 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1027 | static inline int __bfs_forwards(struct lock_list *src_entry, |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1028 | void *data, |
| 1029 | int (*match)(struct lock_list *entry, void *data), |
| 1030 | struct lock_list **target_entry) |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1031 | { |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1032 | return __bfs(src_entry, data, match, target_entry, 1); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1033 | |
| 1034 | } |
| 1035 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1036 | static inline int __bfs_backwards(struct lock_list *src_entry, |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1037 | void *data, |
| 1038 | int (*match)(struct lock_list *entry, void *data), |
| 1039 | struct lock_list **target_entry) |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1040 | { |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1041 | return __bfs(src_entry, data, match, target_entry, 0); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1042 | |
| 1043 | } |
| 1044 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1045 | /* |
| 1046 | * Recursive, forwards-direction lock-dependency checking, used for |
| 1047 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe |
| 1048 | * checking. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1049 | */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1050 | |
| 1051 | /* |
| 1052 | * Print a dependency chain entry (this is only done when a deadlock |
| 1053 | * has been detected): |
| 1054 | */ |
| 1055 | static noinline int |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1056 | print_circular_bug_entry(struct lock_list *target, int depth) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1057 | { |
| 1058 | if (debug_locks_silent) |
| 1059 | return 0; |
| 1060 | printk("\n-> #%u", depth); |
| 1061 | print_lock_name(target->class); |
| 1062 | printk(":\n"); |
| 1063 | print_stack_trace(&target->trace, 6); |
| 1064 | |
| 1065 | return 0; |
| 1066 | } |
| 1067 | |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1068 | static void |
| 1069 | print_circular_lock_scenario(struct held_lock *src, |
| 1070 | struct held_lock *tgt, |
| 1071 | struct lock_list *prt) |
| 1072 | { |
| 1073 | struct lock_class *source = hlock_class(src); |
| 1074 | struct lock_class *target = hlock_class(tgt); |
| 1075 | struct lock_class *parent = prt->class; |
| 1076 | |
| 1077 | /* |
| 1078 | * A direct locking problem where unsafe_class lock is taken |
| 1079 | * directly by safe_class lock, then all we need to show |
| 1080 | * is the deadlock scenario, as it is obvious that the |
| 1081 | * unsafe lock is taken under the safe lock. |
| 1082 | * |
| 1083 | * But if there is a chain instead, where the safe lock takes |
| 1084 | * an intermediate lock (middle_class) where this lock is |
| 1085 | * not the same as the safe lock, then the lock chain is |
| 1086 | * used to describe the problem. Otherwise we would need |
| 1087 | * to show a different CPU case for each link in the chain |
| 1088 | * from the safe_class lock to the unsafe_class lock. |
| 1089 | */ |
| 1090 | if (parent != source) { |
| 1091 | printk("Chain exists of:\n "); |
| 1092 | __print_lock_name(source); |
| 1093 | printk(" --> "); |
| 1094 | __print_lock_name(parent); |
| 1095 | printk(" --> "); |
| 1096 | __print_lock_name(target); |
| 1097 | printk("\n\n"); |
| 1098 | } |
| 1099 | |
| 1100 | printk(" Possible unsafe locking scenario:\n\n"); |
| 1101 | printk(" CPU0 CPU1\n"); |
| 1102 | printk(" ---- ----\n"); |
| 1103 | printk(" lock("); |
| 1104 | __print_lock_name(target); |
| 1105 | printk(");\n"); |
| 1106 | printk(" lock("); |
| 1107 | __print_lock_name(parent); |
| 1108 | printk(");\n"); |
| 1109 | printk(" lock("); |
| 1110 | __print_lock_name(target); |
| 1111 | printk(");\n"); |
| 1112 | printk(" lock("); |
| 1113 | __print_lock_name(source); |
| 1114 | printk(");\n"); |
| 1115 | printk("\n *** DEADLOCK ***\n\n"); |
| 1116 | } |
| 1117 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1118 | /* |
| 1119 | * When a circular dependency is detected, print the |
| 1120 | * header first: |
| 1121 | */ |
| 1122 | static noinline int |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1123 | print_circular_bug_header(struct lock_list *entry, unsigned int depth, |
| 1124 | struct held_lock *check_src, |
| 1125 | struct held_lock *check_tgt) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1126 | { |
| 1127 | struct task_struct *curr = current; |
| 1128 | |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1129 | if (debug_locks_silent) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1130 | return 0; |
| 1131 | |
| 1132 | printk("\n=======================================================\n"); |
| 1133 | printk( "[ INFO: possible circular locking dependency detected ]\n"); |
| 1134 | print_kernel_version(); |
| 1135 | printk( "-------------------------------------------------------\n"); |
| 1136 | printk("%s/%d is trying to acquire lock:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1137 | curr->comm, task_pid_nr(curr)); |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1138 | print_lock(check_src); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1139 | printk("\nbut task is already holding lock:\n"); |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1140 | print_lock(check_tgt); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1141 | printk("\nwhich lock already depends on the new lock.\n\n"); |
| 1142 | printk("\nthe existing dependency chain (in reverse order) is:\n"); |
| 1143 | |
| 1144 | print_circular_bug_entry(entry, depth); |
| 1145 | |
| 1146 | return 0; |
| 1147 | } |
| 1148 | |
Ming Lei | 9e2d551 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1149 | static inline int class_equal(struct lock_list *entry, void *data) |
| 1150 | { |
| 1151 | return entry->class == data; |
| 1152 | } |
| 1153 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1154 | static noinline int print_circular_bug(struct lock_list *this, |
| 1155 | struct lock_list *target, |
| 1156 | struct held_lock *check_src, |
| 1157 | struct held_lock *check_tgt) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1158 | { |
| 1159 | struct task_struct *curr = current; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1160 | struct lock_list *parent; |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1161 | struct lock_list *first_parent; |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1162 | int depth; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1163 | |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1164 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1165 | return 0; |
| 1166 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1167 | if (!save_trace(&this->trace)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1168 | return 0; |
| 1169 | |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1170 | depth = get_lock_depth(target); |
| 1171 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1172 | print_circular_bug_header(target, depth, check_src, check_tgt); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1173 | |
| 1174 | parent = get_lock_parent(target); |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1175 | first_parent = parent; |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1176 | |
| 1177 | while (parent) { |
| 1178 | print_circular_bug_entry(parent, --depth); |
| 1179 | parent = get_lock_parent(parent); |
| 1180 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1181 | |
| 1182 | printk("\nother info that might help us debug this:\n\n"); |
Steven Rostedt | f418581 | 2011-04-20 21:41:55 -0400 | [diff] [blame] | 1183 | print_circular_lock_scenario(check_src, check_tgt, |
| 1184 | first_parent); |
| 1185 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1186 | lockdep_print_held_locks(curr); |
| 1187 | |
| 1188 | printk("\nstack backtrace:\n"); |
| 1189 | dump_stack(); |
| 1190 | |
| 1191 | return 0; |
| 1192 | } |
| 1193 | |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1194 | static noinline int print_bfs_bug(int ret) |
| 1195 | { |
| 1196 | if (!debug_locks_off_graph_unlock()) |
| 1197 | return 0; |
| 1198 | |
| 1199 | WARN(1, "lockdep bfs error:%d\n", ret); |
| 1200 | |
| 1201 | return 0; |
| 1202 | } |
| 1203 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1204 | static int noop_count(struct lock_list *entry, void *data) |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1205 | { |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1206 | (*(unsigned long *)data)++; |
| 1207 | return 0; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1208 | } |
| 1209 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1210 | unsigned long __lockdep_count_forward_deps(struct lock_list *this) |
| 1211 | { |
| 1212 | unsigned long count = 0; |
| 1213 | struct lock_list *uninitialized_var(target_entry); |
| 1214 | |
| 1215 | __bfs_forwards(this, (void *)&count, noop_count, &target_entry); |
| 1216 | |
| 1217 | return count; |
| 1218 | } |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1219 | unsigned long lockdep_count_forward_deps(struct lock_class *class) |
| 1220 | { |
| 1221 | unsigned long ret, flags; |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1222 | struct lock_list this; |
| 1223 | |
| 1224 | this.parent = NULL; |
| 1225 | this.class = class; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1226 | |
| 1227 | local_irq_save(flags); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1228 | arch_spin_lock(&lockdep_lock); |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1229 | ret = __lockdep_count_forward_deps(&this); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1230 | arch_spin_unlock(&lockdep_lock); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1231 | local_irq_restore(flags); |
| 1232 | |
| 1233 | return ret; |
| 1234 | } |
| 1235 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1236 | unsigned long __lockdep_count_backward_deps(struct lock_list *this) |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1237 | { |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1238 | unsigned long count = 0; |
| 1239 | struct lock_list *uninitialized_var(target_entry); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1240 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1241 | __bfs_backwards(this, (void *)&count, noop_count, &target_entry); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1242 | |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1243 | return count; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1244 | } |
| 1245 | |
| 1246 | unsigned long lockdep_count_backward_deps(struct lock_class *class) |
| 1247 | { |
| 1248 | unsigned long ret, flags; |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1249 | struct lock_list this; |
| 1250 | |
| 1251 | this.parent = NULL; |
| 1252 | this.class = class; |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1253 | |
| 1254 | local_irq_save(flags); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1255 | arch_spin_lock(&lockdep_lock); |
Ming Lei | ef68102 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1256 | ret = __lockdep_count_backward_deps(&this); |
Thomas Gleixner | 0199c4e | 2009-12-02 20:01:25 +0100 | [diff] [blame] | 1257 | arch_spin_unlock(&lockdep_lock); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1258 | local_irq_restore(flags); |
| 1259 | |
| 1260 | return ret; |
| 1261 | } |
| 1262 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1263 | /* |
| 1264 | * Prove that the dependency graph starting at <entry> can not |
| 1265 | * lead to <target>. Print an error and return 0 if it does. |
| 1266 | */ |
| 1267 | static noinline int |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1268 | check_noncircular(struct lock_list *root, struct lock_class *target, |
| 1269 | struct lock_list **target_entry) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1270 | { |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1271 | int result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1272 | |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 1273 | debug_atomic_inc(nr_cyclic_checks); |
David Miller | 419ca3f | 2008-07-29 21:45:03 -0700 | [diff] [blame] | 1274 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1275 | result = __bfs_forwards(root, target, class_equal, target_entry); |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1276 | |
| 1277 | return result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1278 | } |
| 1279 | |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 1280 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1281 | /* |
| 1282 | * Forwards and backwards subgraph searching, for the purposes of |
| 1283 | * proving that two subgraphs can be connected by a new dependency |
| 1284 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. |
| 1285 | */ |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1286 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1287 | static inline int usage_match(struct lock_list *entry, void *bit) |
| 1288 | { |
| 1289 | return entry->class->usage_mask & (1 << (enum lock_usage_bit)bit); |
| 1290 | } |
| 1291 | |
| 1292 | |
| 1293 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1294 | /* |
| 1295 | * Find a node in the forwards-direction dependency sub-graph starting |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1296 | * at @root->class that matches @bit. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1297 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1298 | * Return 0 if such a node exists in the subgraph, and put that node |
| 1299 | * into *@target_entry. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1300 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1301 | * Return 1 otherwise and keep *@target_entry unchanged. |
| 1302 | * Return <0 on error. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1303 | */ |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1304 | static int |
| 1305 | find_usage_forwards(struct lock_list *root, enum lock_usage_bit bit, |
| 1306 | struct lock_list **target_entry) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1307 | { |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1308 | int result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1309 | |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 1310 | debug_atomic_inc(nr_find_usage_forwards_checks); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1311 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1312 | result = __bfs_forwards(root, (void *)bit, usage_match, target_entry); |
| 1313 | |
| 1314 | return result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1315 | } |
| 1316 | |
| 1317 | /* |
| 1318 | * Find a node in the backwards-direction dependency sub-graph starting |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1319 | * at @root->class that matches @bit. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1320 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1321 | * Return 0 if such a node exists in the subgraph, and put that node |
| 1322 | * into *@target_entry. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1323 | * |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1324 | * Return 1 otherwise and keep *@target_entry unchanged. |
| 1325 | * Return <0 on error. |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1326 | */ |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1327 | static int |
| 1328 | find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, |
| 1329 | struct lock_list **target_entry) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1330 | { |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1331 | int result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1332 | |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 1333 | debug_atomic_inc(nr_find_usage_backwards_checks); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1334 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1335 | result = __bfs_backwards(root, (void *)bit, usage_match, target_entry); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1336 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1337 | return result; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1338 | } |
| 1339 | |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1340 | static void print_lock_class_header(struct lock_class *class, int depth) |
| 1341 | { |
| 1342 | int bit; |
| 1343 | |
| 1344 | printk("%*s->", depth, ""); |
| 1345 | print_lock_name(class); |
| 1346 | printk(" ops: %lu", class->ops); |
| 1347 | printk(" {\n"); |
| 1348 | |
| 1349 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { |
| 1350 | if (class->usage_mask & (1 << bit)) { |
| 1351 | int len = depth; |
| 1352 | |
| 1353 | len += printk("%*s %s", depth, "", usage_str[bit]); |
| 1354 | len += printk(" at:\n"); |
| 1355 | print_stack_trace(class->usage_traces + bit, len); |
| 1356 | } |
| 1357 | } |
| 1358 | printk("%*s }\n", depth, ""); |
| 1359 | |
| 1360 | printk("%*s ... key at: ",depth,""); |
| 1361 | print_ip_sym((unsigned long)class->key); |
| 1362 | } |
| 1363 | |
| 1364 | /* |
| 1365 | * printk the shortest lock dependencies from @start to @end in reverse order: |
| 1366 | */ |
| 1367 | static void __used |
| 1368 | print_shortest_lock_dependencies(struct lock_list *leaf, |
| 1369 | struct lock_list *root) |
| 1370 | { |
| 1371 | struct lock_list *entry = leaf; |
| 1372 | int depth; |
| 1373 | |
| 1374 | /*compute depth from generated tree by BFS*/ |
| 1375 | depth = get_lock_depth(leaf); |
| 1376 | |
| 1377 | do { |
| 1378 | print_lock_class_header(entry->class, depth); |
| 1379 | printk("%*s ... acquired at:\n", depth, ""); |
| 1380 | print_stack_trace(&entry->trace, 2); |
| 1381 | printk("\n"); |
| 1382 | |
| 1383 | if (depth == 0 && (entry != root)) { |
| 1384 | printk("lockdep:%s bad BFS generated tree\n", __func__); |
| 1385 | break; |
| 1386 | } |
| 1387 | |
| 1388 | entry = get_lock_parent(entry); |
| 1389 | depth--; |
| 1390 | } while (entry && (depth >= 0)); |
| 1391 | |
| 1392 | return; |
| 1393 | } |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1394 | |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1395 | static void |
| 1396 | print_irq_lock_scenario(struct lock_list *safe_entry, |
| 1397 | struct lock_list *unsafe_entry, |
| 1398 | struct held_lock *prev, |
| 1399 | struct held_lock *next) |
| 1400 | { |
| 1401 | struct lock_class *safe_class = safe_entry->class; |
| 1402 | struct lock_class *unsafe_class = unsafe_entry->class; |
| 1403 | struct lock_class *middle_class = hlock_class(prev); |
| 1404 | |
| 1405 | if (middle_class == safe_class) |
| 1406 | middle_class = hlock_class(next); |
| 1407 | |
| 1408 | /* |
| 1409 | * A direct locking problem where unsafe_class lock is taken |
| 1410 | * directly by safe_class lock, then all we need to show |
| 1411 | * is the deadlock scenario, as it is obvious that the |
| 1412 | * unsafe lock is taken under the safe lock. |
| 1413 | * |
| 1414 | * But if there is a chain instead, where the safe lock takes |
| 1415 | * an intermediate lock (middle_class) where this lock is |
| 1416 | * not the same as the safe lock, then the lock chain is |
| 1417 | * used to describe the problem. Otherwise we would need |
| 1418 | * to show a different CPU case for each link in the chain |
| 1419 | * from the safe_class lock to the unsafe_class lock. |
| 1420 | */ |
| 1421 | if (middle_class != unsafe_class) { |
| 1422 | printk("Chain exists of:\n "); |
| 1423 | __print_lock_name(safe_class); |
| 1424 | printk(" --> "); |
| 1425 | __print_lock_name(middle_class); |
| 1426 | printk(" --> "); |
| 1427 | __print_lock_name(unsafe_class); |
| 1428 | printk("\n\n"); |
| 1429 | } |
| 1430 | |
| 1431 | printk(" Possible interrupt unsafe locking scenario:\n\n"); |
| 1432 | printk(" CPU0 CPU1\n"); |
| 1433 | printk(" ---- ----\n"); |
| 1434 | printk(" lock("); |
| 1435 | __print_lock_name(unsafe_class); |
| 1436 | printk(");\n"); |
| 1437 | printk(" local_irq_disable();\n"); |
| 1438 | printk(" lock("); |
| 1439 | __print_lock_name(safe_class); |
| 1440 | printk(");\n"); |
| 1441 | printk(" lock("); |
| 1442 | __print_lock_name(middle_class); |
| 1443 | printk(");\n"); |
| 1444 | printk(" <Interrupt>\n"); |
| 1445 | printk(" lock("); |
| 1446 | __print_lock_name(safe_class); |
| 1447 | printk(");\n"); |
| 1448 | printk("\n *** DEADLOCK ***\n\n"); |
| 1449 | } |
| 1450 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1451 | static int |
| 1452 | print_bad_irq_dependency(struct task_struct *curr, |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1453 | struct lock_list *prev_root, |
| 1454 | struct lock_list *next_root, |
| 1455 | struct lock_list *backwards_entry, |
| 1456 | struct lock_list *forwards_entry, |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1457 | struct held_lock *prev, |
| 1458 | struct held_lock *next, |
| 1459 | enum lock_usage_bit bit1, |
| 1460 | enum lock_usage_bit bit2, |
| 1461 | const char *irqclass) |
| 1462 | { |
| 1463 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
| 1464 | return 0; |
| 1465 | |
| 1466 | printk("\n======================================================\n"); |
| 1467 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", |
| 1468 | irqclass, irqclass); |
| 1469 | print_kernel_version(); |
| 1470 | printk( "------------------------------------------------------\n"); |
| 1471 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1472 | curr->comm, task_pid_nr(curr), |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1473 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
| 1474 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, |
| 1475 | curr->hardirqs_enabled, |
| 1476 | curr->softirqs_enabled); |
| 1477 | print_lock(next); |
| 1478 | |
| 1479 | printk("\nand this task is already holding:\n"); |
| 1480 | print_lock(prev); |
| 1481 | printk("which would create a new lock dependency:\n"); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1482 | print_lock_name(hlock_class(prev)); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1483 | printk(" ->"); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1484 | print_lock_name(hlock_class(next)); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1485 | printk("\n"); |
| 1486 | |
| 1487 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", |
| 1488 | irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1489 | print_lock_name(backwards_entry->class); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1490 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
| 1491 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1492 | print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1493 | |
| 1494 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1495 | print_lock_name(forwards_entry->class); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1496 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
| 1497 | printk("..."); |
| 1498 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1499 | print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1500 | |
| 1501 | printk("\nother info that might help us debug this:\n\n"); |
Steven Rostedt | 3003eba | 2011-04-20 21:41:54 -0400 | [diff] [blame] | 1502 | print_irq_lock_scenario(backwards_entry, forwards_entry, prev, next); |
| 1503 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1504 | lockdep_print_held_locks(curr); |
| 1505 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1506 | printk("\nthe dependencies between %s-irq-safe lock", irqclass); |
| 1507 | printk(" and the holding lock:\n"); |
| 1508 | if (!save_trace(&prev_root->trace)) |
| 1509 | return 0; |
| 1510 | print_shortest_lock_dependencies(backwards_entry, prev_root); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1511 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1512 | printk("\nthe dependencies between the lock to be acquired"); |
| 1513 | printk(" and %s-irq-unsafe lock:\n", irqclass); |
| 1514 | if (!save_trace(&next_root->trace)) |
| 1515 | return 0; |
| 1516 | print_shortest_lock_dependencies(forwards_entry, next_root); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1517 | |
| 1518 | printk("\nstack backtrace:\n"); |
| 1519 | dump_stack(); |
| 1520 | |
| 1521 | return 0; |
| 1522 | } |
| 1523 | |
| 1524 | static int |
| 1525 | check_usage(struct task_struct *curr, struct held_lock *prev, |
| 1526 | struct held_lock *next, enum lock_usage_bit bit_backwards, |
| 1527 | enum lock_usage_bit bit_forwards, const char *irqclass) |
| 1528 | { |
| 1529 | int ret; |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1530 | struct lock_list this, that; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1531 | struct lock_list *uninitialized_var(target_entry); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1532 | struct lock_list *uninitialized_var(target_entry1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1533 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1534 | this.parent = NULL; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1535 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1536 | this.class = hlock_class(prev); |
| 1537 | ret = find_usage_backwards(&this, bit_backwards, &target_entry); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1538 | if (ret < 0) |
| 1539 | return print_bfs_bug(ret); |
| 1540 | if (ret == 1) |
| 1541 | return ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1542 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1543 | that.parent = NULL; |
| 1544 | that.class = hlock_class(next); |
| 1545 | ret = find_usage_forwards(&that, bit_forwards, &target_entry1); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1546 | if (ret < 0) |
| 1547 | return print_bfs_bug(ret); |
| 1548 | if (ret == 1) |
| 1549 | return ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1550 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1551 | return print_bad_irq_dependency(curr, &this, &that, |
| 1552 | target_entry, target_entry1, |
| 1553 | prev, next, |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1554 | bit_backwards, bit_forwards, irqclass); |
| 1555 | } |
| 1556 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1557 | static const char *state_names[] = { |
| 1558 | #define LOCKDEP_STATE(__STATE) \ |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 1559 | __stringify(__STATE), |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1560 | #include "lockdep_states.h" |
| 1561 | #undef LOCKDEP_STATE |
| 1562 | }; |
| 1563 | |
| 1564 | static const char *state_rnames[] = { |
| 1565 | #define LOCKDEP_STATE(__STATE) \ |
Peter Zijlstra | b4b136f | 2009-01-29 14:50:36 +0100 | [diff] [blame] | 1566 | __stringify(__STATE)"-READ", |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1567 | #include "lockdep_states.h" |
| 1568 | #undef LOCKDEP_STATE |
| 1569 | }; |
| 1570 | |
| 1571 | static inline const char *state_name(enum lock_usage_bit bit) |
| 1572 | { |
| 1573 | return (bit & 1) ? state_rnames[bit >> 2] : state_names[bit >> 2]; |
| 1574 | } |
| 1575 | |
| 1576 | static int exclusive_bit(int new_bit) |
| 1577 | { |
| 1578 | /* |
| 1579 | * USED_IN |
| 1580 | * USED_IN_READ |
| 1581 | * ENABLED |
| 1582 | * ENABLED_READ |
| 1583 | * |
| 1584 | * bit 0 - write/read |
| 1585 | * bit 1 - used_in/enabled |
| 1586 | * bit 2+ state |
| 1587 | */ |
| 1588 | |
| 1589 | int state = new_bit & ~3; |
| 1590 | int dir = new_bit & 2; |
| 1591 | |
| 1592 | /* |
| 1593 | * keep state, bit flip the direction and strip read. |
| 1594 | */ |
| 1595 | return state | (dir ^ 2); |
| 1596 | } |
| 1597 | |
| 1598 | static int check_irq_usage(struct task_struct *curr, struct held_lock *prev, |
| 1599 | struct held_lock *next, enum lock_usage_bit bit) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1600 | { |
| 1601 | /* |
| 1602 | * Prove that the new dependency does not connect a hardirq-safe |
| 1603 | * lock with a hardirq-unsafe lock - to achieve this we search |
| 1604 | * the backwards-subgraph starting at <prev>, and the |
| 1605 | * forwards-subgraph starting at <next>: |
| 1606 | */ |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1607 | if (!check_usage(curr, prev, next, bit, |
| 1608 | exclusive_bit(bit), state_name(bit))) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1609 | return 0; |
| 1610 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1611 | bit++; /* _READ */ |
| 1612 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1613 | /* |
| 1614 | * Prove that the new dependency does not connect a hardirq-safe-read |
| 1615 | * lock with a hardirq-unsafe lock - to achieve this we search |
| 1616 | * the backwards-subgraph starting at <prev>, and the |
| 1617 | * forwards-subgraph starting at <next>: |
| 1618 | */ |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1619 | if (!check_usage(curr, prev, next, bit, |
| 1620 | exclusive_bit(bit), state_name(bit))) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1621 | return 0; |
| 1622 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1623 | return 1; |
| 1624 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1625 | |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1626 | static int |
| 1627 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, |
| 1628 | struct held_lock *next) |
| 1629 | { |
| 1630 | #define LOCKDEP_STATE(__STATE) \ |
| 1631 | if (!check_irq_usage(curr, prev, next, LOCK_USED_IN_##__STATE)) \ |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 1632 | return 0; |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 1633 | #include "lockdep_states.h" |
| 1634 | #undef LOCKDEP_STATE |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 1635 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1636 | return 1; |
| 1637 | } |
| 1638 | |
| 1639 | static void inc_chains(void) |
| 1640 | { |
| 1641 | if (current->hardirq_context) |
| 1642 | nr_hardirq_chains++; |
| 1643 | else { |
| 1644 | if (current->softirq_context) |
| 1645 | nr_softirq_chains++; |
| 1646 | else |
| 1647 | nr_process_chains++; |
| 1648 | } |
| 1649 | } |
| 1650 | |
| 1651 | #else |
| 1652 | |
| 1653 | static inline int |
| 1654 | check_prev_add_irq(struct task_struct *curr, struct held_lock *prev, |
| 1655 | struct held_lock *next) |
| 1656 | { |
| 1657 | return 1; |
| 1658 | } |
| 1659 | |
| 1660 | static inline void inc_chains(void) |
| 1661 | { |
| 1662 | nr_process_chains++; |
| 1663 | } |
| 1664 | |
| 1665 | #endif |
| 1666 | |
Steven Rostedt | 48702ec | 2011-04-20 21:41:56 -0400 | [diff] [blame^] | 1667 | static void |
| 1668 | print_deadlock_scenario(struct held_lock *nxt, |
| 1669 | struct held_lock *prv) |
| 1670 | { |
| 1671 | struct lock_class *next = hlock_class(nxt); |
| 1672 | struct lock_class *prev = hlock_class(prv); |
| 1673 | |
| 1674 | printk(" Possible unsafe locking scenario:\n\n"); |
| 1675 | printk(" CPU0\n"); |
| 1676 | printk(" ----\n"); |
| 1677 | printk(" lock("); |
| 1678 | __print_lock_name(prev); |
| 1679 | printk(");\n"); |
| 1680 | printk(" lock("); |
| 1681 | __print_lock_name(next); |
| 1682 | printk(");\n"); |
| 1683 | printk("\n *** DEADLOCK ***\n\n"); |
| 1684 | printk(" May be due to missing lock nesting notation\n\n"); |
| 1685 | } |
| 1686 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1687 | static int |
| 1688 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, |
| 1689 | struct held_lock *next) |
| 1690 | { |
| 1691 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
| 1692 | return 0; |
| 1693 | |
| 1694 | printk("\n=============================================\n"); |
| 1695 | printk( "[ INFO: possible recursive locking detected ]\n"); |
| 1696 | print_kernel_version(); |
| 1697 | printk( "---------------------------------------------\n"); |
| 1698 | printk("%s/%d is trying to acquire lock:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 1699 | curr->comm, task_pid_nr(curr)); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1700 | print_lock(next); |
| 1701 | printk("\nbut task is already holding lock:\n"); |
| 1702 | print_lock(prev); |
| 1703 | |
| 1704 | printk("\nother info that might help us debug this:\n"); |
Steven Rostedt | 48702ec | 2011-04-20 21:41:56 -0400 | [diff] [blame^] | 1705 | print_deadlock_scenario(next, prev); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1706 | lockdep_print_held_locks(curr); |
| 1707 | |
| 1708 | printk("\nstack backtrace:\n"); |
| 1709 | dump_stack(); |
| 1710 | |
| 1711 | return 0; |
| 1712 | } |
| 1713 | |
| 1714 | /* |
| 1715 | * Check whether we are holding such a class already. |
| 1716 | * |
| 1717 | * (Note that this has to be done separately, because the graph cannot |
| 1718 | * detect such classes of deadlocks.) |
| 1719 | * |
| 1720 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read |
| 1721 | */ |
| 1722 | static int |
| 1723 | check_deadlock(struct task_struct *curr, struct held_lock *next, |
| 1724 | struct lockdep_map *next_instance, int read) |
| 1725 | { |
| 1726 | struct held_lock *prev; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1727 | struct held_lock *nest = NULL; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1728 | int i; |
| 1729 | |
| 1730 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 1731 | prev = curr->held_locks + i; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1732 | |
| 1733 | if (prev->instance == next->nest_lock) |
| 1734 | nest = prev; |
| 1735 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1736 | if (hlock_class(prev) != hlock_class(next)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1737 | continue; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1738 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1739 | /* |
| 1740 | * Allow read-after-read recursion of the same |
| 1741 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
| 1742 | */ |
| 1743 | if ((read == 2) && prev->read) |
| 1744 | return 2; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 1745 | |
| 1746 | /* |
| 1747 | * We're holding the nest_lock, which serializes this lock's |
| 1748 | * nesting behaviour. |
| 1749 | */ |
| 1750 | if (nest) |
| 1751 | return 2; |
| 1752 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1753 | return print_deadlock_bug(curr, prev, next); |
| 1754 | } |
| 1755 | return 1; |
| 1756 | } |
| 1757 | |
| 1758 | /* |
| 1759 | * There was a chain-cache miss, and we are about to add a new dependency |
| 1760 | * to a previous lock. We recursively validate the following rules: |
| 1761 | * |
| 1762 | * - would the adding of the <prev> -> <next> dependency create a |
| 1763 | * circular dependency in the graph? [== circular deadlock] |
| 1764 | * |
| 1765 | * - does the new prev->next dependency connect any hardirq-safe lock |
| 1766 | * (in the full backwards-subgraph starting at <prev>) with any |
| 1767 | * hardirq-unsafe lock (in the full forwards-subgraph starting at |
| 1768 | * <next>)? [== illegal lock inversion with hardirq contexts] |
| 1769 | * |
| 1770 | * - does the new prev->next dependency connect any softirq-safe lock |
| 1771 | * (in the full backwards-subgraph starting at <prev>) with any |
| 1772 | * softirq-unsafe lock (in the full forwards-subgraph starting at |
| 1773 | * <next>)? [== illegal lock inversion with softirq contexts] |
| 1774 | * |
| 1775 | * any of these scenarios could lead to a deadlock. |
| 1776 | * |
| 1777 | * Then if all the validations pass, we add the forwards and backwards |
| 1778 | * dependency. |
| 1779 | */ |
| 1780 | static int |
| 1781 | check_prev_add(struct task_struct *curr, struct held_lock *prev, |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1782 | struct held_lock *next, int distance, int trylock_loop) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1783 | { |
| 1784 | struct lock_list *entry; |
| 1785 | int ret; |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1786 | struct lock_list this; |
| 1787 | struct lock_list *uninitialized_var(target_entry); |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1788 | /* |
| 1789 | * Static variable, serialized by the graph_lock(). |
| 1790 | * |
| 1791 | * We use this static variable to save the stack trace in case |
| 1792 | * we call into this function multiple times due to encountering |
| 1793 | * trylocks in the held lock stack. |
| 1794 | */ |
| 1795 | static struct stack_trace trace; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1796 | |
| 1797 | /* |
| 1798 | * Prove that the new <prev> -> <next> dependency would not |
| 1799 | * create a circular dependency in the graph. (We do this by |
| 1800 | * forward-recursing into the graph starting at <next>, and |
| 1801 | * checking whether we can reach <prev>.) |
| 1802 | * |
| 1803 | * We are using global variables to control the recursion, to |
| 1804 | * keep the stackframe size of the recursive functions low: |
| 1805 | */ |
Ming Lei | db0002a | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1806 | this.class = hlock_class(next); |
| 1807 | this.parent = NULL; |
| 1808 | ret = check_noncircular(&this, hlock_class(prev), &target_entry); |
| 1809 | if (unlikely(!ret)) |
| 1810 | return print_circular_bug(&this, target_entry, next, prev); |
| 1811 | else if (unlikely(ret < 0)) |
| 1812 | return print_bfs_bug(ret); |
Ming Lei | c94aa5c | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 1813 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1814 | if (!check_prev_add_irq(curr, prev, next)) |
| 1815 | return 0; |
| 1816 | |
| 1817 | /* |
| 1818 | * For recursive read-locks we do all the dependency checks, |
| 1819 | * but we dont store read-triggered dependencies (only |
| 1820 | * write-triggered dependencies). This ensures that only the |
| 1821 | * write-side dependencies matter, and that if for example a |
| 1822 | * write-lock never takes any other locks, then the reads are |
| 1823 | * equivalent to a NOP. |
| 1824 | */ |
| 1825 | if (next->read == 2 || prev->read == 2) |
| 1826 | return 1; |
| 1827 | /* |
| 1828 | * Is the <prev> -> <next> dependency already present? |
| 1829 | * |
| 1830 | * (this may occur even though this is a new chain: consider |
| 1831 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 |
| 1832 | * chains - the second one will be new, but L1 already has |
| 1833 | * L2 added to its dependency list, due to the first chain.) |
| 1834 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1835 | list_for_each_entry(entry, &hlock_class(prev)->locks_after, entry) { |
| 1836 | if (entry->class == hlock_class(next)) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1837 | if (distance == 1) |
| 1838 | entry->distance = 1; |
| 1839 | return 2; |
| 1840 | } |
| 1841 | } |
| 1842 | |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1843 | if (!trylock_loop && !save_trace(&trace)) |
| 1844 | return 0; |
| 1845 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1846 | /* |
| 1847 | * Ok, all validations passed, add the new lock |
| 1848 | * to the previous lock's dependency list: |
| 1849 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1850 | ret = add_lock_to_list(hlock_class(prev), hlock_class(next), |
| 1851 | &hlock_class(prev)->locks_after, |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1852 | next->acquire_ip, distance, &trace); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1853 | |
| 1854 | if (!ret) |
| 1855 | return 0; |
| 1856 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1857 | ret = add_lock_to_list(hlock_class(next), hlock_class(prev), |
| 1858 | &hlock_class(next)->locks_before, |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1859 | next->acquire_ip, distance, &trace); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1860 | if (!ret) |
| 1861 | return 0; |
| 1862 | |
| 1863 | /* |
| 1864 | * Debugging printouts: |
| 1865 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1866 | if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1867 | graph_unlock(); |
| 1868 | printk("\n new dependency: "); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1869 | print_lock_name(hlock_class(prev)); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1870 | printk(" => "); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1871 | print_lock_name(hlock_class(next)); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1872 | printk("\n"); |
| 1873 | dump_stack(); |
| 1874 | return graph_lock(); |
| 1875 | } |
| 1876 | return 1; |
| 1877 | } |
| 1878 | |
| 1879 | /* |
| 1880 | * Add the dependency to all directly-previous locks that are 'relevant'. |
| 1881 | * The ones that are relevant are (in increasing distance from curr): |
| 1882 | * all consecutive trylock entries and the final non-trylock entry - or |
| 1883 | * the end of this context's lock-chain - whichever comes first. |
| 1884 | */ |
| 1885 | static int |
| 1886 | check_prevs_add(struct task_struct *curr, struct held_lock *next) |
| 1887 | { |
| 1888 | int depth = curr->lockdep_depth; |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1889 | int trylock_loop = 0; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1890 | struct held_lock *hlock; |
| 1891 | |
| 1892 | /* |
| 1893 | * Debugging checks. |
| 1894 | * |
| 1895 | * Depth must not be zero for a non-head lock: |
| 1896 | */ |
| 1897 | if (!depth) |
| 1898 | goto out_bug; |
| 1899 | /* |
| 1900 | * At least two relevant locks must exist for this |
| 1901 | * to be a head: |
| 1902 | */ |
| 1903 | if (curr->held_locks[depth].irq_context != |
| 1904 | curr->held_locks[depth-1].irq_context) |
| 1905 | goto out_bug; |
| 1906 | |
| 1907 | for (;;) { |
| 1908 | int distance = curr->lockdep_depth - depth + 1; |
| 1909 | hlock = curr->held_locks + depth-1; |
| 1910 | /* |
| 1911 | * Only non-recursive-read entries get new dependencies |
| 1912 | * added: |
| 1913 | */ |
| 1914 | if (hlock->read != 2) { |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1915 | if (!check_prev_add(curr, hlock, next, |
| 1916 | distance, trylock_loop)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1917 | return 0; |
| 1918 | /* |
| 1919 | * Stop after the first non-trylock entry, |
| 1920 | * as non-trylock entries have added their |
| 1921 | * own direct dependencies already, so this |
| 1922 | * lock is connected to them indirectly: |
| 1923 | */ |
| 1924 | if (!hlock->trylock) |
| 1925 | break; |
| 1926 | } |
| 1927 | depth--; |
| 1928 | /* |
| 1929 | * End of lock-stack? |
| 1930 | */ |
| 1931 | if (!depth) |
| 1932 | break; |
| 1933 | /* |
| 1934 | * Stop the search if we cross into another context: |
| 1935 | */ |
| 1936 | if (curr->held_locks[depth].irq_context != |
| 1937 | curr->held_locks[depth-1].irq_context) |
| 1938 | break; |
Yong Zhang | 4726f2a | 2010-05-04 14:16:48 +0800 | [diff] [blame] | 1939 | trylock_loop = 1; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1940 | } |
| 1941 | return 1; |
| 1942 | out_bug: |
| 1943 | if (!debug_locks_off_graph_unlock()) |
| 1944 | return 0; |
| 1945 | |
| 1946 | WARN_ON(1); |
| 1947 | |
| 1948 | return 0; |
| 1949 | } |
| 1950 | |
| 1951 | unsigned long nr_lock_chains; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 1952 | struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
Huang, Ying | cd1a28e | 2008-06-23 11:20:54 +0800 | [diff] [blame] | 1953 | int nr_chain_hlocks; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 1954 | static u16 chain_hlocks[MAX_LOCKDEP_CHAIN_HLOCKS]; |
| 1955 | |
| 1956 | struct lock_class *lock_chain_get_class(struct lock_chain *chain, int i) |
| 1957 | { |
| 1958 | return lock_classes + chain_hlocks[chain->base + i]; |
| 1959 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 1960 | |
| 1961 | /* |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1962 | * Look up a dependency chain. If the key is not present yet then |
Jarek Poplawski | 9e860d0 | 2007-05-08 00:30:12 -0700 | [diff] [blame] | 1963 | * add it and return 1 - in this case the new dependency chain is |
| 1964 | * validated. If the key is already hashed, return 0. |
| 1965 | * (On return with 1 graph_lock is held.) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1966 | */ |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 1967 | static inline int lookup_chain_cache(struct task_struct *curr, |
| 1968 | struct held_lock *hlock, |
| 1969 | u64 chain_key) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1970 | { |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 1971 | struct lock_class *class = hlock_class(hlock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1972 | struct list_head *hash_head = chainhashentry(chain_key); |
| 1973 | struct lock_chain *chain; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 1974 | struct held_lock *hlock_curr, *hlock_next; |
Huang, Ying | cd1a28e | 2008-06-23 11:20:54 +0800 | [diff] [blame] | 1975 | int i, j, n, cn; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1976 | |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 1977 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 1978 | return 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1979 | /* |
| 1980 | * We can walk it lock-free, because entries only get added |
| 1981 | * to the hash: |
| 1982 | */ |
| 1983 | list_for_each_entry(chain, hash_head, entry) { |
| 1984 | if (chain->chain_key == chain_key) { |
| 1985 | cache_hit: |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 1986 | debug_atomic_inc(chain_lookup_hits); |
Ingo Molnar | 81fc685 | 2006-12-13 00:34:40 -0800 | [diff] [blame] | 1987 | if (very_verbose(class)) |
Andrew Morton | 755cd90 | 2006-12-29 16:49:14 -0800 | [diff] [blame] | 1988 | printk("\nhash chain already cached, key: " |
| 1989 | "%016Lx tail class: [%p] %s\n", |
| 1990 | (unsigned long long)chain_key, |
| 1991 | class->key, class->name); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1992 | return 0; |
| 1993 | } |
| 1994 | } |
Ingo Molnar | 81fc685 | 2006-12-13 00:34:40 -0800 | [diff] [blame] | 1995 | if (very_verbose(class)) |
Andrew Morton | 755cd90 | 2006-12-29 16:49:14 -0800 | [diff] [blame] | 1996 | printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n", |
| 1997 | (unsigned long long)chain_key, class->key, class->name); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1998 | /* |
| 1999 | * Allocate a new chain entry from the static array, and add |
| 2000 | * it to the hash: |
| 2001 | */ |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2002 | if (!graph_lock()) |
| 2003 | return 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2004 | /* |
| 2005 | * We have to walk the chain again locked - to avoid duplicates: |
| 2006 | */ |
| 2007 | list_for_each_entry(chain, hash_head, entry) { |
| 2008 | if (chain->chain_key == chain_key) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2009 | graph_unlock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2010 | goto cache_hit; |
| 2011 | } |
| 2012 | } |
| 2013 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2014 | if (!debug_locks_off_graph_unlock()) |
| 2015 | return 0; |
| 2016 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2017 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
| 2018 | printk("turning off the locking correctness validator.\n"); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 2019 | dump_stack(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2020 | return 0; |
| 2021 | } |
| 2022 | chain = lock_chains + nr_lock_chains++; |
| 2023 | chain->chain_key = chain_key; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2024 | chain->irq_context = hlock->irq_context; |
| 2025 | /* Find the first held_lock of current chain */ |
| 2026 | hlock_next = hlock; |
| 2027 | for (i = curr->lockdep_depth - 1; i >= 0; i--) { |
| 2028 | hlock_curr = curr->held_locks + i; |
| 2029 | if (hlock_curr->irq_context != hlock_next->irq_context) |
| 2030 | break; |
| 2031 | hlock_next = hlock; |
| 2032 | } |
| 2033 | i++; |
| 2034 | chain->depth = curr->lockdep_depth + 1 - i; |
Huang, Ying | cd1a28e | 2008-06-23 11:20:54 +0800 | [diff] [blame] | 2035 | cn = nr_chain_hlocks; |
| 2036 | while (cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS) { |
| 2037 | n = cmpxchg(&nr_chain_hlocks, cn, cn + chain->depth); |
| 2038 | if (n == cn) |
| 2039 | break; |
| 2040 | cn = n; |
| 2041 | } |
| 2042 | if (likely(cn + chain->depth <= MAX_LOCKDEP_CHAIN_HLOCKS)) { |
| 2043 | chain->base = cn; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2044 | for (j = 0; j < chain->depth - 1; j++, i++) { |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2045 | int lock_id = curr->held_locks[i].class_idx - 1; |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2046 | chain_hlocks[chain->base + j] = lock_id; |
| 2047 | } |
| 2048 | chain_hlocks[chain->base + j] = class - lock_classes; |
| 2049 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2050 | list_add_tail_rcu(&chain->entry, hash_head); |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2051 | debug_atomic_inc(chain_lookup_misses); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2052 | inc_chains(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2053 | |
| 2054 | return 1; |
| 2055 | } |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2056 | |
| 2057 | static int validate_chain(struct task_struct *curr, struct lockdep_map *lock, |
Johannes Berg | 4e6045f | 2007-10-18 23:39:55 -0700 | [diff] [blame] | 2058 | struct held_lock *hlock, int chain_head, u64 chain_key) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2059 | { |
| 2060 | /* |
| 2061 | * Trylock needs to maintain the stack of held locks, but it |
| 2062 | * does not add new dependencies, because trylock can be done |
| 2063 | * in any order. |
| 2064 | * |
| 2065 | * We look up the chain_key and do the O(N^2) check and update of |
| 2066 | * the dependencies only if this is a new dependency chain. |
| 2067 | * (If lookup_chain_cache() returns with 1 it acquires |
| 2068 | * graph_lock for us) |
| 2069 | */ |
| 2070 | if (!hlock->trylock && (hlock->check == 2) && |
Huang, Ying | 443cd50 | 2008-06-20 16:39:21 +0800 | [diff] [blame] | 2071 | lookup_chain_cache(curr, hlock, chain_key)) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2072 | /* |
| 2073 | * Check whether last held lock: |
| 2074 | * |
| 2075 | * - is irq-safe, if this lock is irq-unsafe |
| 2076 | * - is softirq-safe, if this lock is hardirq-unsafe |
| 2077 | * |
| 2078 | * And check whether the new lock's dependency graph |
| 2079 | * could lead back to the previous lock. |
| 2080 | * |
| 2081 | * any of these scenarios could lead to a deadlock. If |
| 2082 | * All validations |
| 2083 | */ |
| 2084 | int ret = check_deadlock(curr, hlock, lock, hlock->read); |
| 2085 | |
| 2086 | if (!ret) |
| 2087 | return 0; |
| 2088 | /* |
| 2089 | * Mark recursive read, as we jump over it when |
| 2090 | * building dependencies (just like we jump over |
| 2091 | * trylock entries): |
| 2092 | */ |
| 2093 | if (ret == 2) |
| 2094 | hlock->read = 2; |
| 2095 | /* |
| 2096 | * Add dependency only if this lock is not the head |
| 2097 | * of the chain, and if it's not a secondary read-lock: |
| 2098 | */ |
| 2099 | if (!chain_head && ret != 2) |
| 2100 | if (!check_prevs_add(curr, hlock)) |
| 2101 | return 0; |
| 2102 | graph_unlock(); |
| 2103 | } else |
| 2104 | /* after lookup_chain_cache(): */ |
| 2105 | if (unlikely(!debug_locks)) |
| 2106 | return 0; |
| 2107 | |
| 2108 | return 1; |
| 2109 | } |
| 2110 | #else |
| 2111 | static inline int validate_chain(struct task_struct *curr, |
| 2112 | struct lockdep_map *lock, struct held_lock *hlock, |
Gregory Haskins | 3aa416b | 2007-10-11 22:11:11 +0200 | [diff] [blame] | 2113 | int chain_head, u64 chain_key) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2114 | { |
| 2115 | return 1; |
| 2116 | } |
Peter Zijlstra | ca58abc | 2007-07-19 01:48:53 -0700 | [diff] [blame] | 2117 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2118 | |
| 2119 | /* |
| 2120 | * We are building curr_chain_key incrementally, so double-check |
| 2121 | * it from scratch, to make sure that it's done correctly: |
| 2122 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2123 | static void check_chain_key(struct task_struct *curr) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2124 | { |
| 2125 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2126 | struct held_lock *hlock, *prev_hlock = NULL; |
| 2127 | unsigned int i, id; |
| 2128 | u64 chain_key = 0; |
| 2129 | |
| 2130 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 2131 | hlock = curr->held_locks + i; |
| 2132 | if (chain_key != hlock->prev_chain_key) { |
| 2133 | debug_locks_off(); |
Arjan van de Ven | 2df8b1d | 2008-07-30 12:43:11 -0700 | [diff] [blame] | 2134 | WARN(1, "hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2135 | curr->lockdep_depth, i, |
| 2136 | (unsigned long long)chain_key, |
| 2137 | (unsigned long long)hlock->prev_chain_key); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2138 | return; |
| 2139 | } |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2140 | id = hlock->class_idx - 1; |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 2141 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
| 2142 | return; |
| 2143 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2144 | if (prev_hlock && (prev_hlock->irq_context != |
| 2145 | hlock->irq_context)) |
| 2146 | chain_key = 0; |
| 2147 | chain_key = iterate_chain_key(chain_key, id); |
| 2148 | prev_hlock = hlock; |
| 2149 | } |
| 2150 | if (chain_key != curr->curr_chain_key) { |
| 2151 | debug_locks_off(); |
Arjan van de Ven | 2df8b1d | 2008-07-30 12:43:11 -0700 | [diff] [blame] | 2152 | WARN(1, "hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2153 | curr->lockdep_depth, i, |
| 2154 | (unsigned long long)chain_key, |
| 2155 | (unsigned long long)curr->curr_chain_key); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2156 | } |
| 2157 | #endif |
| 2158 | } |
| 2159 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2160 | static int |
| 2161 | print_usage_bug(struct task_struct *curr, struct held_lock *this, |
| 2162 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) |
| 2163 | { |
| 2164 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
| 2165 | return 0; |
| 2166 | |
| 2167 | printk("\n=================================\n"); |
| 2168 | printk( "[ INFO: inconsistent lock state ]\n"); |
| 2169 | print_kernel_version(); |
| 2170 | printk( "---------------------------------\n"); |
| 2171 | |
| 2172 | printk("inconsistent {%s} -> {%s} usage.\n", |
| 2173 | usage_str[prev_bit], usage_str[new_bit]); |
| 2174 | |
| 2175 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 2176 | curr->comm, task_pid_nr(curr), |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2177 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
| 2178 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, |
| 2179 | trace_hardirqs_enabled(curr), |
| 2180 | trace_softirqs_enabled(curr)); |
| 2181 | print_lock(this); |
| 2182 | |
| 2183 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2184 | print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2185 | |
| 2186 | print_irqtrace_events(curr); |
| 2187 | printk("\nother info that might help us debug this:\n"); |
| 2188 | lockdep_print_held_locks(curr); |
| 2189 | |
| 2190 | printk("\nstack backtrace:\n"); |
| 2191 | dump_stack(); |
| 2192 | |
| 2193 | return 0; |
| 2194 | } |
| 2195 | |
| 2196 | /* |
| 2197 | * Print out an error if an invalid bit is set: |
| 2198 | */ |
| 2199 | static inline int |
| 2200 | valid_state(struct task_struct *curr, struct held_lock *this, |
| 2201 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) |
| 2202 | { |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2203 | if (unlikely(hlock_class(this)->usage_mask & (1 << bad_bit))) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2204 | return print_usage_bug(curr, this, bad_bit, new_bit); |
| 2205 | return 1; |
| 2206 | } |
| 2207 | |
| 2208 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
| 2209 | enum lock_usage_bit new_bit); |
| 2210 | |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2211 | #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2212 | |
| 2213 | /* |
| 2214 | * print irq inversion bug: |
| 2215 | */ |
| 2216 | static int |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2217 | print_irq_inversion_bug(struct task_struct *curr, |
| 2218 | struct lock_list *root, struct lock_list *other, |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2219 | struct held_lock *this, int forwards, |
| 2220 | const char *irqclass) |
| 2221 | { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2222 | if (!debug_locks_off_graph_unlock() || debug_locks_silent) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2223 | return 0; |
| 2224 | |
| 2225 | printk("\n=========================================================\n"); |
| 2226 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 2227 | print_kernel_version(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2228 | printk( "---------------------------------------------------------\n"); |
| 2229 | printk("%s/%d just changed the state of lock:\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 2230 | curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2231 | print_lock(this); |
| 2232 | if (forwards) |
Peter Zijlstra | 26575e2 | 2009-03-04 14:53:24 +0100 | [diff] [blame] | 2233 | printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2234 | else |
Peter Zijlstra | 26575e2 | 2009-03-04 14:53:24 +0100 | [diff] [blame] | 2235 | printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2236 | print_lock_name(other->class); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2237 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
| 2238 | |
| 2239 | printk("\nother info that might help us debug this:\n"); |
| 2240 | lockdep_print_held_locks(curr); |
| 2241 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2242 | printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); |
| 2243 | if (!save_trace(&root->trace)) |
| 2244 | return 0; |
| 2245 | print_shortest_lock_dependencies(other, root); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2246 | |
| 2247 | printk("\nstack backtrace:\n"); |
| 2248 | dump_stack(); |
| 2249 | |
| 2250 | return 0; |
| 2251 | } |
| 2252 | |
| 2253 | /* |
| 2254 | * Prove that in the forwards-direction subgraph starting at <this> |
| 2255 | * there is no lock matching <mask>: |
| 2256 | */ |
| 2257 | static int |
| 2258 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, |
| 2259 | enum lock_usage_bit bit, const char *irqclass) |
| 2260 | { |
| 2261 | int ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2262 | struct lock_list root; |
| 2263 | struct lock_list *uninitialized_var(target_entry); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2264 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2265 | root.parent = NULL; |
| 2266 | root.class = hlock_class(this); |
| 2267 | ret = find_usage_forwards(&root, bit, &target_entry); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2268 | if (ret < 0) |
| 2269 | return print_bfs_bug(ret); |
| 2270 | if (ret == 1) |
| 2271 | return ret; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2272 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2273 | return print_irq_inversion_bug(curr, &root, target_entry, |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2274 | this, 1, irqclass); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2275 | } |
| 2276 | |
| 2277 | /* |
| 2278 | * Prove that in the backwards-direction subgraph starting at <this> |
| 2279 | * there is no lock matching <mask>: |
| 2280 | */ |
| 2281 | static int |
| 2282 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, |
| 2283 | enum lock_usage_bit bit, const char *irqclass) |
| 2284 | { |
| 2285 | int ret; |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2286 | struct lock_list root; |
| 2287 | struct lock_list *uninitialized_var(target_entry); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2288 | |
Ming Lei | d7aaba1 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2289 | root.parent = NULL; |
| 2290 | root.class = hlock_class(this); |
| 2291 | ret = find_usage_backwards(&root, bit, &target_entry); |
Peter Zijlstra | af01296 | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2292 | if (ret < 0) |
| 2293 | return print_bfs_bug(ret); |
| 2294 | if (ret == 1) |
| 2295 | return ret; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2296 | |
Ming Lei | 24208ca | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 2297 | return print_irq_inversion_bug(curr, &root, target_entry, |
Oleg Nesterov | 48d5067 | 2010-01-26 19:16:41 +0100 | [diff] [blame] | 2298 | this, 0, irqclass); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2299 | } |
| 2300 | |
Ingo Molnar | 3117df0 | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 2301 | void print_irqtrace_events(struct task_struct *curr) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2302 | { |
| 2303 | printk("irq event stamp: %u\n", curr->irq_events); |
| 2304 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); |
| 2305 | print_ip_sym(curr->hardirq_enable_ip); |
| 2306 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); |
| 2307 | print_ip_sym(curr->hardirq_disable_ip); |
| 2308 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); |
| 2309 | print_ip_sym(curr->softirq_enable_ip); |
| 2310 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); |
| 2311 | print_ip_sym(curr->softirq_disable_ip); |
| 2312 | } |
| 2313 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2314 | static int HARDIRQ_verbose(struct lock_class *class) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2315 | { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2316 | #if HARDIRQ_VERBOSE |
| 2317 | return class_filter(class); |
| 2318 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2319 | return 0; |
| 2320 | } |
| 2321 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2322 | static int SOFTIRQ_verbose(struct lock_class *class) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2323 | { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2324 | #if SOFTIRQ_VERBOSE |
| 2325 | return class_filter(class); |
| 2326 | #endif |
| 2327 | return 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2328 | } |
| 2329 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2330 | static int RECLAIM_FS_verbose(struct lock_class *class) |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2331 | { |
| 2332 | #if RECLAIM_VERBOSE |
| 2333 | return class_filter(class); |
| 2334 | #endif |
| 2335 | return 0; |
| 2336 | } |
| 2337 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2338 | #define STRICT_READ_CHECKS 1 |
| 2339 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2340 | static int (*state_verbose_f[])(struct lock_class *class) = { |
| 2341 | #define LOCKDEP_STATE(__STATE) \ |
| 2342 | __STATE##_verbose, |
| 2343 | #include "lockdep_states.h" |
| 2344 | #undef LOCKDEP_STATE |
| 2345 | }; |
| 2346 | |
| 2347 | static inline int state_verbose(enum lock_usage_bit bit, |
| 2348 | struct lock_class *class) |
| 2349 | { |
| 2350 | return state_verbose_f[bit >> 2](class); |
| 2351 | } |
| 2352 | |
Peter Zijlstra | 42c50d5 | 2009-01-22 16:58:16 +0100 | [diff] [blame] | 2353 | typedef int (*check_usage_f)(struct task_struct *, struct held_lock *, |
| 2354 | enum lock_usage_bit bit, const char *name); |
| 2355 | |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2356 | static int |
Peter Zijlstra | 1c21f14 | 2009-03-04 13:51:13 +0100 | [diff] [blame] | 2357 | mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
| 2358 | enum lock_usage_bit new_bit) |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2359 | { |
Peter Zijlstra | f989209 | 2009-01-22 16:09:59 +0100 | [diff] [blame] | 2360 | int excl_bit = exclusive_bit(new_bit); |
Peter Zijlstra | 9d3651a | 2009-01-22 17:18:32 +0100 | [diff] [blame] | 2361 | int read = new_bit & 1; |
Peter Zijlstra | 42c50d5 | 2009-01-22 16:58:16 +0100 | [diff] [blame] | 2362 | int dir = new_bit & 2; |
| 2363 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2364 | /* |
| 2365 | * mark USED_IN has to look forwards -- to ensure no dependency |
| 2366 | * has ENABLED state, which would allow recursion deadlocks. |
| 2367 | * |
| 2368 | * mark ENABLED has to look backwards -- to ensure no dependee |
| 2369 | * has USED_IN state, which, again, would allow recursion deadlocks. |
| 2370 | */ |
Peter Zijlstra | 42c50d5 | 2009-01-22 16:58:16 +0100 | [diff] [blame] | 2371 | check_usage_f usage = dir ? |
| 2372 | check_usage_backwards : check_usage_forwards; |
Peter Zijlstra | f989209 | 2009-01-22 16:09:59 +0100 | [diff] [blame] | 2373 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2374 | /* |
| 2375 | * Validate that this particular lock does not have conflicting |
| 2376 | * usage states. |
| 2377 | */ |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2378 | if (!valid_state(curr, this, new_bit, excl_bit)) |
| 2379 | return 0; |
Peter Zijlstra | 9d3651a | 2009-01-22 17:18:32 +0100 | [diff] [blame] | 2380 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2381 | /* |
| 2382 | * Validate that the lock dependencies don't have conflicting usage |
| 2383 | * states. |
| 2384 | */ |
| 2385 | if ((!read || !dir || STRICT_READ_CHECKS) && |
Peter Zijlstra | 1c21f14 | 2009-03-04 13:51:13 +0100 | [diff] [blame] | 2386 | !usage(curr, this, excl_bit, state_name(new_bit & ~1))) |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2387 | return 0; |
Peter Zijlstra | 780e820 | 2009-01-22 16:51:29 +0100 | [diff] [blame] | 2388 | |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2389 | /* |
| 2390 | * Check for read in write conflicts |
| 2391 | */ |
| 2392 | if (!read) { |
| 2393 | if (!valid_state(curr, this, new_bit, excl_bit + 1)) |
| 2394 | return 0; |
| 2395 | |
| 2396 | if (STRICT_READ_CHECKS && |
Peter Zijlstra | 4f367d8a | 2009-01-22 18:10:42 +0100 | [diff] [blame] | 2397 | !usage(curr, this, excl_bit + 1, |
| 2398 | state_name(new_bit + 1))) |
Peter Zijlstra | 38aa271 | 2009-01-27 14:53:50 +0100 | [diff] [blame] | 2399 | return 0; |
| 2400 | } |
Peter Zijlstra | 780e820 | 2009-01-22 16:51:29 +0100 | [diff] [blame] | 2401 | |
Peter Zijlstra | cd95302 | 2009-01-22 16:38:21 +0100 | [diff] [blame] | 2402 | if (state_verbose(new_bit, hlock_class(this))) |
Peter Zijlstra | 6a6904d | 2009-01-22 16:07:44 +0100 | [diff] [blame] | 2403 | return 2; |
| 2404 | |
| 2405 | return 1; |
| 2406 | } |
| 2407 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2408 | enum mark_type { |
Peter Zijlstra | 36bfb9b | 2009-01-22 14:12:41 +0100 | [diff] [blame] | 2409 | #define LOCKDEP_STATE(__STATE) __STATE, |
| 2410 | #include "lockdep_states.h" |
| 2411 | #undef LOCKDEP_STATE |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2412 | }; |
| 2413 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2414 | /* |
| 2415 | * Mark all held locks with a usage bit: |
| 2416 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2417 | static int |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2418 | mark_held_locks(struct task_struct *curr, enum mark_type mark) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2419 | { |
| 2420 | enum lock_usage_bit usage_bit; |
| 2421 | struct held_lock *hlock; |
| 2422 | int i; |
| 2423 | |
| 2424 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 2425 | hlock = curr->held_locks + i; |
| 2426 | |
Peter Zijlstra | cf2ad4d | 2009-01-27 13:58:08 +0100 | [diff] [blame] | 2427 | usage_bit = 2 + (mark << 2); /* ENABLED */ |
| 2428 | if (hlock->read) |
| 2429 | usage_bit += 1; /* READ */ |
| 2430 | |
| 2431 | BUG_ON(usage_bit >= LOCK_USAGE_STATES); |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2432 | |
Jarek Poplawski | 4ff773bb | 2007-05-08 00:31:00 -0700 | [diff] [blame] | 2433 | if (!mark_lock(curr, hlock, usage_bit)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2434 | return 0; |
| 2435 | } |
| 2436 | |
| 2437 | return 1; |
| 2438 | } |
| 2439 | |
| 2440 | /* |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2441 | * Hardirqs will be enabled: |
| 2442 | */ |
Heiko Carstens | 6afe40b | 2008-10-28 11:14:58 +0100 | [diff] [blame] | 2443 | void trace_hardirqs_on_caller(unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2444 | { |
| 2445 | struct task_struct *curr = current; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2446 | |
Heiko Carstens | 6afe40b | 2008-10-28 11:14:58 +0100 | [diff] [blame] | 2447 | time_hardirqs_on(CALLER_ADDR0, ip); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2448 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2449 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
| 2450 | return; |
| 2451 | |
Tejun Heo | 2ce802f | 2011-01-20 12:06:35 +0100 | [diff] [blame] | 2452 | if (DEBUG_LOCKS_WARN_ON(unlikely(early_boot_irqs_disabled))) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2453 | return; |
| 2454 | |
| 2455 | if (unlikely(curr->hardirqs_enabled)) { |
Frederic Weisbecker | 8795d77 | 2010-04-15 23:10:42 +0200 | [diff] [blame] | 2456 | /* |
| 2457 | * Neither irq nor preemption are disabled here |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 2458 | * so this is racy by nature but losing one hit |
Frederic Weisbecker | 8795d77 | 2010-04-15 23:10:42 +0200 | [diff] [blame] | 2459 | * in a stat is not a big deal. |
| 2460 | */ |
Frederic Weisbecker | ba697f4 | 2010-05-04 04:47:25 +0200 | [diff] [blame] | 2461 | __debug_atomic_inc(redundant_hardirqs_on); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2462 | return; |
| 2463 | } |
| 2464 | /* we'll do an OFF -> ON transition: */ |
| 2465 | curr->hardirqs_enabled = 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2466 | |
| 2467 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2468 | return; |
| 2469 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
| 2470 | return; |
| 2471 | /* |
| 2472 | * We are going to turn hardirqs on, so set the |
| 2473 | * usage bit for all held locks: |
| 2474 | */ |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2475 | if (!mark_held_locks(curr, HARDIRQ)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2476 | return; |
| 2477 | /* |
| 2478 | * If we have softirqs enabled, then set the usage |
| 2479 | * bit for all held locks. (disabled hardirqs prevented |
| 2480 | * this bit from being set before) |
| 2481 | */ |
| 2482 | if (curr->softirqs_enabled) |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2483 | if (!mark_held_locks(curr, SOFTIRQ)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2484 | return; |
| 2485 | |
| 2486 | curr->hardirq_enable_ip = ip; |
| 2487 | curr->hardirq_enable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2488 | debug_atomic_inc(hardirqs_on_events); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2489 | } |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2490 | EXPORT_SYMBOL(trace_hardirqs_on_caller); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2491 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2492 | void trace_hardirqs_on(void) |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2493 | { |
| 2494 | trace_hardirqs_on_caller(CALLER_ADDR0); |
| 2495 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2496 | EXPORT_SYMBOL(trace_hardirqs_on); |
| 2497 | |
| 2498 | /* |
| 2499 | * Hardirqs were disabled: |
| 2500 | */ |
Heiko Carstens | 6afe40b | 2008-10-28 11:14:58 +0100 | [diff] [blame] | 2501 | void trace_hardirqs_off_caller(unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2502 | { |
| 2503 | struct task_struct *curr = current; |
| 2504 | |
Heiko Carstens | 6afe40b | 2008-10-28 11:14:58 +0100 | [diff] [blame] | 2505 | time_hardirqs_off(CALLER_ADDR0, ip); |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2506 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2507 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
| 2508 | return; |
| 2509 | |
| 2510 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2511 | return; |
| 2512 | |
| 2513 | if (curr->hardirqs_enabled) { |
| 2514 | /* |
| 2515 | * We have done an ON -> OFF transition: |
| 2516 | */ |
| 2517 | curr->hardirqs_enabled = 0; |
Heiko Carstens | 6afe40b | 2008-10-28 11:14:58 +0100 | [diff] [blame] | 2518 | curr->hardirq_disable_ip = ip; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2519 | curr->hardirq_disable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2520 | debug_atomic_inc(hardirqs_off_events); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2521 | } else |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2522 | debug_atomic_inc(redundant_hardirqs_off); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2523 | } |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2524 | EXPORT_SYMBOL(trace_hardirqs_off_caller); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2525 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2526 | void trace_hardirqs_off(void) |
Steven Rostedt | 81d68a9 | 2008-05-12 21:20:42 +0200 | [diff] [blame] | 2527 | { |
| 2528 | trace_hardirqs_off_caller(CALLER_ADDR0); |
| 2529 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2530 | EXPORT_SYMBOL(trace_hardirqs_off); |
| 2531 | |
| 2532 | /* |
| 2533 | * Softirqs will be enabled: |
| 2534 | */ |
| 2535 | void trace_softirqs_on(unsigned long ip) |
| 2536 | { |
| 2537 | struct task_struct *curr = current; |
| 2538 | |
| 2539 | if (unlikely(!debug_locks)) |
| 2540 | return; |
| 2541 | |
| 2542 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2543 | return; |
| 2544 | |
| 2545 | if (curr->softirqs_enabled) { |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2546 | debug_atomic_inc(redundant_softirqs_on); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2547 | return; |
| 2548 | } |
| 2549 | |
| 2550 | /* |
| 2551 | * We'll do an OFF -> ON transition: |
| 2552 | */ |
| 2553 | curr->softirqs_enabled = 1; |
| 2554 | curr->softirq_enable_ip = ip; |
| 2555 | curr->softirq_enable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2556 | debug_atomic_inc(softirqs_on_events); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2557 | /* |
| 2558 | * We are going to turn softirqs on, so set the |
| 2559 | * usage bit for all held locks, if hardirqs are |
| 2560 | * enabled too: |
| 2561 | */ |
| 2562 | if (curr->hardirqs_enabled) |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2563 | mark_held_locks(curr, SOFTIRQ); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2564 | } |
| 2565 | |
| 2566 | /* |
| 2567 | * Softirqs were disabled: |
| 2568 | */ |
| 2569 | void trace_softirqs_off(unsigned long ip) |
| 2570 | { |
| 2571 | struct task_struct *curr = current; |
| 2572 | |
| 2573 | if (unlikely(!debug_locks)) |
| 2574 | return; |
| 2575 | |
| 2576 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2577 | return; |
| 2578 | |
| 2579 | if (curr->softirqs_enabled) { |
| 2580 | /* |
| 2581 | * We have done an ON -> OFF transition: |
| 2582 | */ |
| 2583 | curr->softirqs_enabled = 0; |
| 2584 | curr->softirq_disable_ip = ip; |
| 2585 | curr->softirq_disable_event = ++curr->irq_events; |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2586 | debug_atomic_inc(softirqs_off_events); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2587 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
| 2588 | } else |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2589 | debug_atomic_inc(redundant_softirqs_off); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2590 | } |
| 2591 | |
Peter Zijlstra | 2f85018 | 2009-03-20 11:13:20 +0100 | [diff] [blame] | 2592 | static void __lockdep_trace_alloc(gfp_t gfp_mask, unsigned long flags) |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2593 | { |
| 2594 | struct task_struct *curr = current; |
| 2595 | |
| 2596 | if (unlikely(!debug_locks)) |
| 2597 | return; |
| 2598 | |
| 2599 | /* no reclaim without waiting on it */ |
| 2600 | if (!(gfp_mask & __GFP_WAIT)) |
| 2601 | return; |
| 2602 | |
| 2603 | /* this guy won't enter reclaim */ |
| 2604 | if ((curr->flags & PF_MEMALLOC) && !(gfp_mask & __GFP_NOMEMALLOC)) |
| 2605 | return; |
| 2606 | |
| 2607 | /* We're only interested __GFP_FS allocations for now */ |
| 2608 | if (!(gfp_mask & __GFP_FS)) |
| 2609 | return; |
| 2610 | |
Peter Zijlstra | 2f85018 | 2009-03-20 11:13:20 +0100 | [diff] [blame] | 2611 | if (DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags))) |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2612 | return; |
| 2613 | |
| 2614 | mark_held_locks(curr, RECLAIM_FS); |
| 2615 | } |
| 2616 | |
Peter Zijlstra | 2f85018 | 2009-03-20 11:13:20 +0100 | [diff] [blame] | 2617 | static void check_flags(unsigned long flags); |
| 2618 | |
| 2619 | void lockdep_trace_alloc(gfp_t gfp_mask) |
| 2620 | { |
| 2621 | unsigned long flags; |
| 2622 | |
| 2623 | if (unlikely(current->lockdep_recursion)) |
| 2624 | return; |
| 2625 | |
| 2626 | raw_local_irq_save(flags); |
| 2627 | check_flags(flags); |
| 2628 | current->lockdep_recursion = 1; |
| 2629 | __lockdep_trace_alloc(gfp_mask, flags); |
| 2630 | current->lockdep_recursion = 0; |
| 2631 | raw_local_irq_restore(flags); |
| 2632 | } |
| 2633 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2634 | static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock) |
| 2635 | { |
| 2636 | /* |
| 2637 | * If non-trylock use in a hardirq or softirq context, then |
| 2638 | * mark the lock as used in these contexts: |
| 2639 | */ |
| 2640 | if (!hlock->trylock) { |
| 2641 | if (hlock->read) { |
| 2642 | if (curr->hardirq_context) |
| 2643 | if (!mark_lock(curr, hlock, |
| 2644 | LOCK_USED_IN_HARDIRQ_READ)) |
| 2645 | return 0; |
| 2646 | if (curr->softirq_context) |
| 2647 | if (!mark_lock(curr, hlock, |
| 2648 | LOCK_USED_IN_SOFTIRQ_READ)) |
| 2649 | return 0; |
| 2650 | } else { |
| 2651 | if (curr->hardirq_context) |
| 2652 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ)) |
| 2653 | return 0; |
| 2654 | if (curr->softirq_context) |
| 2655 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ)) |
| 2656 | return 0; |
| 2657 | } |
| 2658 | } |
| 2659 | if (!hlock->hardirqs_off) { |
| 2660 | if (hlock->read) { |
| 2661 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 2662 | LOCK_ENABLED_HARDIRQ_READ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2663 | return 0; |
| 2664 | if (curr->softirqs_enabled) |
| 2665 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 2666 | LOCK_ENABLED_SOFTIRQ_READ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2667 | return 0; |
| 2668 | } else { |
| 2669 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 2670 | LOCK_ENABLED_HARDIRQ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2671 | return 0; |
| 2672 | if (curr->softirqs_enabled) |
| 2673 | if (!mark_lock(curr, hlock, |
Peter Zijlstra | 4fc95e8 | 2009-01-22 13:10:52 +0100 | [diff] [blame] | 2674 | LOCK_ENABLED_SOFTIRQ)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2675 | return 0; |
| 2676 | } |
| 2677 | } |
| 2678 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 2679 | /* |
| 2680 | * We reuse the irq context infrastructure more broadly as a general |
| 2681 | * context checking code. This tests GFP_FS recursion (a lock taken |
| 2682 | * during reclaim for a GFP_FS allocation is held over a GFP_FS |
| 2683 | * allocation). |
| 2684 | */ |
| 2685 | if (!hlock->trylock && (curr->lockdep_reclaim_gfp & __GFP_FS)) { |
| 2686 | if (hlock->read) { |
| 2687 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS_READ)) |
| 2688 | return 0; |
| 2689 | } else { |
| 2690 | if (!mark_lock(curr, hlock, LOCK_USED_IN_RECLAIM_FS)) |
| 2691 | return 0; |
| 2692 | } |
| 2693 | } |
| 2694 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2695 | return 1; |
| 2696 | } |
| 2697 | |
| 2698 | static int separate_irq_context(struct task_struct *curr, |
| 2699 | struct held_lock *hlock) |
| 2700 | { |
| 2701 | unsigned int depth = curr->lockdep_depth; |
| 2702 | |
| 2703 | /* |
| 2704 | * Keep track of points where we cross into an interrupt context: |
| 2705 | */ |
| 2706 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + |
| 2707 | curr->softirq_context; |
| 2708 | if (depth) { |
| 2709 | struct held_lock *prev_hlock; |
| 2710 | |
| 2711 | prev_hlock = curr->held_locks + depth-1; |
| 2712 | /* |
| 2713 | * If we cross into another context, reset the |
| 2714 | * hash key (this also prevents the checking and the |
| 2715 | * adding of the dependency to 'prev'): |
| 2716 | */ |
| 2717 | if (prev_hlock->irq_context != hlock->irq_context) |
| 2718 | return 1; |
| 2719 | } |
| 2720 | return 0; |
| 2721 | } |
| 2722 | |
| 2723 | #else |
| 2724 | |
| 2725 | static inline |
| 2726 | int mark_lock_irq(struct task_struct *curr, struct held_lock *this, |
| 2727 | enum lock_usage_bit new_bit) |
| 2728 | { |
| 2729 | WARN_ON(1); |
| 2730 | return 1; |
| 2731 | } |
| 2732 | |
| 2733 | static inline int mark_irqflags(struct task_struct *curr, |
| 2734 | struct held_lock *hlock) |
| 2735 | { |
| 2736 | return 1; |
| 2737 | } |
| 2738 | |
| 2739 | static inline int separate_irq_context(struct task_struct *curr, |
| 2740 | struct held_lock *hlock) |
| 2741 | { |
| 2742 | return 0; |
| 2743 | } |
| 2744 | |
Peter Zijlstra | 868a23a | 2009-02-15 00:25:21 +0100 | [diff] [blame] | 2745 | void lockdep_trace_alloc(gfp_t gfp_mask) |
| 2746 | { |
| 2747 | } |
| 2748 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2749 | #endif |
| 2750 | |
| 2751 | /* |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2752 | * Mark a lock with a usage bit, and validate the state transition: |
| 2753 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 2754 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
Steven Rostedt | 0764d23 | 2008-05-12 21:20:44 +0200 | [diff] [blame] | 2755 | enum lock_usage_bit new_bit) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2756 | { |
| 2757 | unsigned int new_mask = 1 << new_bit, ret = 1; |
| 2758 | |
| 2759 | /* |
| 2760 | * If already set then do not dirty the cacheline, |
| 2761 | * nor do any checks: |
| 2762 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2763 | if (likely(hlock_class(this)->usage_mask & new_mask)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2764 | return 1; |
| 2765 | |
| 2766 | if (!graph_lock()) |
| 2767 | return 0; |
| 2768 | /* |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 2769 | * Make sure we didn't race: |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2770 | */ |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2771 | if (unlikely(hlock_class(this)->usage_mask & new_mask)) { |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2772 | graph_unlock(); |
| 2773 | return 1; |
| 2774 | } |
| 2775 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2776 | hlock_class(this)->usage_mask |= new_mask; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2777 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2778 | if (!save_trace(hlock_class(this)->usage_traces + new_bit)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2779 | return 0; |
| 2780 | |
| 2781 | switch (new_bit) { |
Peter Zijlstra | 5346417 | 2009-01-22 14:15:53 +0100 | [diff] [blame] | 2782 | #define LOCKDEP_STATE(__STATE) \ |
| 2783 | case LOCK_USED_IN_##__STATE: \ |
| 2784 | case LOCK_USED_IN_##__STATE##_READ: \ |
| 2785 | case LOCK_ENABLED_##__STATE: \ |
| 2786 | case LOCK_ENABLED_##__STATE##_READ: |
| 2787 | #include "lockdep_states.h" |
| 2788 | #undef LOCKDEP_STATE |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2789 | ret = mark_lock_irq(curr, this, new_bit); |
| 2790 | if (!ret) |
| 2791 | return 0; |
| 2792 | break; |
| 2793 | case LOCK_USED: |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2794 | debug_atomic_dec(nr_unused_locks); |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2795 | break; |
| 2796 | default: |
| 2797 | if (!debug_locks_off_graph_unlock()) |
| 2798 | return 0; |
| 2799 | WARN_ON(1); |
| 2800 | return 0; |
| 2801 | } |
| 2802 | |
| 2803 | graph_unlock(); |
| 2804 | |
| 2805 | /* |
| 2806 | * We must printk outside of the graph_lock: |
| 2807 | */ |
| 2808 | if (ret == 2) { |
| 2809 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); |
| 2810 | print_lock(this); |
| 2811 | print_irqtrace_events(curr); |
| 2812 | dump_stack(); |
| 2813 | } |
| 2814 | |
| 2815 | return ret; |
| 2816 | } |
| 2817 | |
| 2818 | /* |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2819 | * Initialize a lock instance's lock-class mapping info: |
| 2820 | */ |
| 2821 | void lockdep_init_map(struct lockdep_map *lock, const char *name, |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 2822 | struct lock_class_key *key, int subclass) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2823 | { |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 2824 | int i; |
| 2825 | |
| 2826 | for (i = 0; i < NR_LOCKDEP_CACHING_CLASSES; i++) |
| 2827 | lock->class_cache[i] = NULL; |
| 2828 | |
Peter Zijlstra | c8a2500 | 2009-04-17 09:40:49 +0200 | [diff] [blame] | 2829 | #ifdef CONFIG_LOCK_STAT |
| 2830 | lock->cpu = raw_smp_processor_id(); |
| 2831 | #endif |
| 2832 | |
| 2833 | if (DEBUG_LOCKS_WARN_ON(!name)) { |
| 2834 | lock->name = "NULL"; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2835 | return; |
Peter Zijlstra | c8a2500 | 2009-04-17 09:40:49 +0200 | [diff] [blame] | 2836 | } |
| 2837 | |
| 2838 | lock->name = name; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2839 | |
| 2840 | if (DEBUG_LOCKS_WARN_ON(!key)) |
| 2841 | return; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2842 | /* |
| 2843 | * Sanity check, the lock-class key must be persistent: |
| 2844 | */ |
| 2845 | if (!static_obj(key)) { |
| 2846 | printk("BUG: key %p not in .data!\n", key); |
| 2847 | DEBUG_LOCKS_WARN_ON(1); |
| 2848 | return; |
| 2849 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2850 | lock->key = key; |
Peter Zijlstra | c8a2500 | 2009-04-17 09:40:49 +0200 | [diff] [blame] | 2851 | |
| 2852 | if (unlikely(!debug_locks)) |
| 2853 | return; |
| 2854 | |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 2855 | if (subclass) |
| 2856 | register_lock_class(lock, subclass, 1); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2857 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2858 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
| 2859 | |
Peter Zijlstra | 1704f47 | 2010-03-19 01:37:42 +0100 | [diff] [blame] | 2860 | struct lock_class_key __lockdep_no_validate__; |
| 2861 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2862 | /* |
| 2863 | * This gets called for every mutex_lock*()/spin_lock*() operation. |
| 2864 | * We maintain the dependency maps and validate the locking attempt: |
| 2865 | */ |
| 2866 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
| 2867 | int trylock, int read, int check, int hardirqs_off, |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 2868 | struct lockdep_map *nest_lock, unsigned long ip, |
| 2869 | int references) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2870 | { |
| 2871 | struct task_struct *curr = current; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2872 | struct lock_class *class = NULL; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2873 | struct held_lock *hlock; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2874 | unsigned int depth, id; |
| 2875 | int chain_head = 0; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 2876 | int class_idx; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2877 | u64 chain_key; |
| 2878 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 2879 | if (!prove_locking) |
| 2880 | check = 1; |
| 2881 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2882 | if (unlikely(!debug_locks)) |
| 2883 | return 0; |
| 2884 | |
| 2885 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2886 | return 0; |
| 2887 | |
Peter Zijlstra | 1704f47 | 2010-03-19 01:37:42 +0100 | [diff] [blame] | 2888 | if (lock->key == &__lockdep_no_validate__) |
| 2889 | check = 1; |
| 2890 | |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 2891 | if (subclass < NR_LOCKDEP_CACHING_CLASSES) |
| 2892 | class = lock->class_cache[subclass]; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2893 | /* |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 2894 | * Not cached? |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2895 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2896 | if (unlikely(!class)) { |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 2897 | class = register_lock_class(lock, subclass, 0); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2898 | if (!class) |
| 2899 | return 0; |
| 2900 | } |
Frederic Weisbecker | bd6d29c | 2010-04-06 00:10:17 +0200 | [diff] [blame] | 2901 | atomic_inc((atomic_t *)&class->ops); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2902 | if (very_verbose(class)) { |
| 2903 | printk("\nacquire class [%p] %s", class->key, class->name); |
| 2904 | if (class->name_version > 1) |
| 2905 | printk("#%d", class->name_version); |
| 2906 | printk("\n"); |
| 2907 | dump_stack(); |
| 2908 | } |
| 2909 | |
| 2910 | /* |
| 2911 | * Add the lock to the list of currently held locks. |
| 2912 | * (we dont increase the depth just yet, up until the |
| 2913 | * dependency checks are done) |
| 2914 | */ |
| 2915 | depth = curr->lockdep_depth; |
| 2916 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
| 2917 | return 0; |
| 2918 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 2919 | class_idx = class - lock_classes + 1; |
| 2920 | |
| 2921 | if (depth) { |
| 2922 | hlock = curr->held_locks + depth - 1; |
| 2923 | if (hlock->class_idx == class_idx && nest_lock) { |
| 2924 | if (hlock->references) |
| 2925 | hlock->references++; |
| 2926 | else |
| 2927 | hlock->references = 2; |
| 2928 | |
| 2929 | return 1; |
| 2930 | } |
| 2931 | } |
| 2932 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2933 | hlock = curr->held_locks + depth; |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 2934 | if (DEBUG_LOCKS_WARN_ON(!class)) |
| 2935 | return 0; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 2936 | hlock->class_idx = class_idx; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2937 | hlock->acquire_ip = ip; |
| 2938 | hlock->instance = lock; |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 2939 | hlock->nest_lock = nest_lock; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2940 | hlock->trylock = trylock; |
| 2941 | hlock->read = read; |
| 2942 | hlock->check = check; |
Dmitry Baryshkov | 6951b12 | 2008-08-18 04:26:37 +0400 | [diff] [blame] | 2943 | hlock->hardirqs_off = !!hardirqs_off; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 2944 | hlock->references = references; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 2945 | #ifdef CONFIG_LOCK_STAT |
| 2946 | hlock->waittime_stamp = 0; |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 2947 | hlock->holdtime_stamp = lockstat_clock(); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 2948 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2949 | |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2950 | if (check == 2 && !mark_irqflags(curr, hlock)) |
| 2951 | return 0; |
| 2952 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2953 | /* mark it as used: */ |
Jarek Poplawski | 4ff773bb | 2007-05-08 00:31:00 -0700 | [diff] [blame] | 2954 | if (!mark_lock(curr, hlock, LOCK_USED)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2955 | return 0; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2956 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2957 | /* |
Gautham R Shenoy | 17aacfb | 2007-10-28 20:47:01 +0100 | [diff] [blame] | 2958 | * Calculate the chain hash: it's the combined hash of all the |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2959 | * lock keys along the dependency chain. We save the hash value |
| 2960 | * at every step so that we can get the current hash easily |
| 2961 | * after unlock. The chain hash is then used to cache dependency |
| 2962 | * results. |
| 2963 | * |
| 2964 | * The 'key ID' is what is the most compact key value to drive |
| 2965 | * the hash, not class->key. |
| 2966 | */ |
| 2967 | id = class - lock_classes; |
| 2968 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
| 2969 | return 0; |
| 2970 | |
| 2971 | chain_key = curr->curr_chain_key; |
| 2972 | if (!depth) { |
| 2973 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
| 2974 | return 0; |
| 2975 | chain_head = 1; |
| 2976 | } |
| 2977 | |
| 2978 | hlock->prev_chain_key = chain_key; |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2979 | if (separate_irq_context(curr, hlock)) { |
| 2980 | chain_key = 0; |
| 2981 | chain_head = 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2982 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2983 | chain_key = iterate_chain_key(chain_key, id); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2984 | |
Gregory Haskins | 3aa416b | 2007-10-11 22:11:11 +0200 | [diff] [blame] | 2985 | if (!validate_chain(curr, lock, hlock, chain_head, chain_key)) |
Peter Zijlstra | 8e18257 | 2007-07-19 01:48:54 -0700 | [diff] [blame] | 2986 | return 0; |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 2987 | |
Gregory Haskins | 3aa416b | 2007-10-11 22:11:11 +0200 | [diff] [blame] | 2988 | curr->curr_chain_key = chain_key; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2989 | curr->lockdep_depth++; |
| 2990 | check_chain_key(curr); |
Jarek Poplawski | 60e114d | 2007-02-20 13:58:00 -0800 | [diff] [blame] | 2991 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2992 | if (unlikely(!debug_locks)) |
| 2993 | return 0; |
| 2994 | #endif |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2995 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
| 2996 | debug_locks_off(); |
| 2997 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); |
| 2998 | printk("turning off the locking correctness validator.\n"); |
Peter Zijlstra | eedeeab | 2009-03-18 12:38:47 +0100 | [diff] [blame] | 2999 | dump_stack(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3000 | return 0; |
| 3001 | } |
Jarek Poplawski | 381a229 | 2007-02-10 01:44:58 -0800 | [diff] [blame] | 3002 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3003 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
| 3004 | max_lockdep_depth = curr->lockdep_depth; |
| 3005 | |
| 3006 | return 1; |
| 3007 | } |
| 3008 | |
| 3009 | static int |
| 3010 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
| 3011 | unsigned long ip) |
| 3012 | { |
| 3013 | if (!debug_locks_off()) |
| 3014 | return 0; |
| 3015 | if (debug_locks_silent) |
| 3016 | return 0; |
| 3017 | |
| 3018 | printk("\n=====================================\n"); |
| 3019 | printk( "[ BUG: bad unlock balance detected! ]\n"); |
| 3020 | printk( "-------------------------------------\n"); |
| 3021 | printk("%s/%d is trying to release lock (", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 3022 | curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3023 | print_lockdep_cache(lock); |
| 3024 | printk(") at:\n"); |
| 3025 | print_ip_sym(ip); |
| 3026 | printk("but there are no more locks to release!\n"); |
| 3027 | printk("\nother info that might help us debug this:\n"); |
| 3028 | lockdep_print_held_locks(curr); |
| 3029 | |
| 3030 | printk("\nstack backtrace:\n"); |
| 3031 | dump_stack(); |
| 3032 | |
| 3033 | return 0; |
| 3034 | } |
| 3035 | |
| 3036 | /* |
| 3037 | * Common debugging checks for both nested and non-nested unlock: |
| 3038 | */ |
| 3039 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, |
| 3040 | unsigned long ip) |
| 3041 | { |
| 3042 | if (unlikely(!debug_locks)) |
| 3043 | return 0; |
| 3044 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 3045 | return 0; |
| 3046 | |
| 3047 | if (curr->lockdep_depth <= 0) |
| 3048 | return print_unlock_inbalance_bug(curr, lock, ip); |
| 3049 | |
| 3050 | return 1; |
| 3051 | } |
| 3052 | |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3053 | static int match_held_lock(struct held_lock *hlock, struct lockdep_map *lock) |
| 3054 | { |
| 3055 | if (hlock->instance == lock) |
| 3056 | return 1; |
| 3057 | |
| 3058 | if (hlock->references) { |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 3059 | struct lock_class *class = lock->class_cache[0]; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3060 | |
| 3061 | if (!class) |
| 3062 | class = look_up_lock_class(lock, 0); |
| 3063 | |
| 3064 | if (DEBUG_LOCKS_WARN_ON(!class)) |
| 3065 | return 0; |
| 3066 | |
| 3067 | if (DEBUG_LOCKS_WARN_ON(!hlock->nest_lock)) |
| 3068 | return 0; |
| 3069 | |
| 3070 | if (hlock->class_idx == class - lock_classes + 1) |
| 3071 | return 1; |
| 3072 | } |
| 3073 | |
| 3074 | return 0; |
| 3075 | } |
| 3076 | |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3077 | static int |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3078 | __lock_set_class(struct lockdep_map *lock, const char *name, |
| 3079 | struct lock_class_key *key, unsigned int subclass, |
| 3080 | unsigned long ip) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3081 | { |
| 3082 | struct task_struct *curr = current; |
| 3083 | struct held_lock *hlock, *prev_hlock; |
| 3084 | struct lock_class *class; |
| 3085 | unsigned int depth; |
| 3086 | int i; |
| 3087 | |
| 3088 | depth = curr->lockdep_depth; |
| 3089 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 3090 | return 0; |
| 3091 | |
| 3092 | prev_hlock = NULL; |
| 3093 | for (i = depth-1; i >= 0; i--) { |
| 3094 | hlock = curr->held_locks + i; |
| 3095 | /* |
| 3096 | * We must not cross into another context: |
| 3097 | */ |
| 3098 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) |
| 3099 | break; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3100 | if (match_held_lock(hlock, lock)) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3101 | goto found_it; |
| 3102 | prev_hlock = hlock; |
| 3103 | } |
| 3104 | return print_unlock_inbalance_bug(curr, lock, ip); |
| 3105 | |
| 3106 | found_it: |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3107 | lockdep_init_map(lock, name, key, 0); |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3108 | class = register_lock_class(lock, subclass, 0); |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3109 | hlock->class_idx = class - lock_classes + 1; |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3110 | |
| 3111 | curr->lockdep_depth = i; |
| 3112 | curr->curr_chain_key = hlock->prev_chain_key; |
| 3113 | |
| 3114 | for (; i < depth; i++) { |
| 3115 | hlock = curr->held_locks + i; |
| 3116 | if (!__lock_acquire(hlock->instance, |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3117 | hlock_class(hlock)->subclass, hlock->trylock, |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3118 | hlock->read, hlock->check, hlock->hardirqs_off, |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3119 | hlock->nest_lock, hlock->acquire_ip, |
| 3120 | hlock->references)) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3121 | return 0; |
| 3122 | } |
| 3123 | |
| 3124 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth)) |
| 3125 | return 0; |
| 3126 | return 1; |
| 3127 | } |
| 3128 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3129 | /* |
| 3130 | * Remove the lock to the list of currently held locks in a |
| 3131 | * potentially non-nested (out of order) manner. This is a |
| 3132 | * relatively rare operation, as all the unlock APIs default |
| 3133 | * to nested mode (which uses lock_release()): |
| 3134 | */ |
| 3135 | static int |
| 3136 | lock_release_non_nested(struct task_struct *curr, |
| 3137 | struct lockdep_map *lock, unsigned long ip) |
| 3138 | { |
| 3139 | struct held_lock *hlock, *prev_hlock; |
| 3140 | unsigned int depth; |
| 3141 | int i; |
| 3142 | |
| 3143 | /* |
| 3144 | * Check whether the lock exists in the current stack |
| 3145 | * of held locks: |
| 3146 | */ |
| 3147 | depth = curr->lockdep_depth; |
| 3148 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 3149 | return 0; |
| 3150 | |
| 3151 | prev_hlock = NULL; |
| 3152 | for (i = depth-1; i >= 0; i--) { |
| 3153 | hlock = curr->held_locks + i; |
| 3154 | /* |
| 3155 | * We must not cross into another context: |
| 3156 | */ |
| 3157 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) |
| 3158 | break; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3159 | if (match_held_lock(hlock, lock)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3160 | goto found_it; |
| 3161 | prev_hlock = hlock; |
| 3162 | } |
| 3163 | return print_unlock_inbalance_bug(curr, lock, ip); |
| 3164 | |
| 3165 | found_it: |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3166 | if (hlock->instance == lock) |
| 3167 | lock_release_holdtime(hlock); |
| 3168 | |
| 3169 | if (hlock->references) { |
| 3170 | hlock->references--; |
| 3171 | if (hlock->references) { |
| 3172 | /* |
| 3173 | * We had, and after removing one, still have |
| 3174 | * references, the current lock stack is still |
| 3175 | * valid. We're done! |
| 3176 | */ |
| 3177 | return 1; |
| 3178 | } |
| 3179 | } |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3180 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3181 | /* |
| 3182 | * We have the right lock to unlock, 'hlock' points to it. |
| 3183 | * Now we remove it from the stack, and add back the other |
| 3184 | * entries (if any), recalculating the hash along the way: |
| 3185 | */ |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3186 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3187 | curr->lockdep_depth = i; |
| 3188 | curr->curr_chain_key = hlock->prev_chain_key; |
| 3189 | |
| 3190 | for (i++; i < depth; i++) { |
| 3191 | hlock = curr->held_locks + i; |
| 3192 | if (!__lock_acquire(hlock->instance, |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3193 | hlock_class(hlock)->subclass, hlock->trylock, |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3194 | hlock->read, hlock->check, hlock->hardirqs_off, |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3195 | hlock->nest_lock, hlock->acquire_ip, |
| 3196 | hlock->references)) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3197 | return 0; |
| 3198 | } |
| 3199 | |
| 3200 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
| 3201 | return 0; |
| 3202 | return 1; |
| 3203 | } |
| 3204 | |
| 3205 | /* |
| 3206 | * Remove the lock to the list of currently held locks - this gets |
| 3207 | * called on mutex_unlock()/spin_unlock*() (or on a failed |
| 3208 | * mutex_lock_interruptible()). This is done for unlocks that nest |
| 3209 | * perfectly. (i.e. the current top of the lock-stack is unlocked) |
| 3210 | */ |
| 3211 | static int lock_release_nested(struct task_struct *curr, |
| 3212 | struct lockdep_map *lock, unsigned long ip) |
| 3213 | { |
| 3214 | struct held_lock *hlock; |
| 3215 | unsigned int depth; |
| 3216 | |
| 3217 | /* |
| 3218 | * Pop off the top of the lock stack: |
| 3219 | */ |
| 3220 | depth = curr->lockdep_depth - 1; |
| 3221 | hlock = curr->held_locks + depth; |
| 3222 | |
| 3223 | /* |
| 3224 | * Is the unlock non-nested: |
| 3225 | */ |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3226 | if (hlock->instance != lock || hlock->references) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3227 | return lock_release_non_nested(curr, lock, ip); |
| 3228 | curr->lockdep_depth--; |
| 3229 | |
| 3230 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) |
| 3231 | return 0; |
| 3232 | |
| 3233 | curr->curr_chain_key = hlock->prev_chain_key; |
| 3234 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3235 | lock_release_holdtime(hlock); |
| 3236 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3237 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 3238 | hlock->prev_chain_key = 0; |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3239 | hlock->class_idx = 0; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3240 | hlock->acquire_ip = 0; |
| 3241 | hlock->irq_context = 0; |
| 3242 | #endif |
| 3243 | return 1; |
| 3244 | } |
| 3245 | |
| 3246 | /* |
| 3247 | * Remove the lock to the list of currently held locks - this gets |
| 3248 | * called on mutex_unlock()/spin_unlock*() (or on a failed |
| 3249 | * mutex_lock_interruptible()). This is done for unlocks that nest |
| 3250 | * perfectly. (i.e. the current top of the lock-stack is unlocked) |
| 3251 | */ |
| 3252 | static void |
| 3253 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
| 3254 | { |
| 3255 | struct task_struct *curr = current; |
| 3256 | |
| 3257 | if (!check_unlock(curr, lock, ip)) |
| 3258 | return; |
| 3259 | |
| 3260 | if (nested) { |
| 3261 | if (!lock_release_nested(curr, lock, ip)) |
| 3262 | return; |
| 3263 | } else { |
| 3264 | if (!lock_release_non_nested(curr, lock, ip)) |
| 3265 | return; |
| 3266 | } |
| 3267 | |
| 3268 | check_chain_key(curr); |
| 3269 | } |
| 3270 | |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 3271 | static int __lock_is_held(struct lockdep_map *lock) |
| 3272 | { |
| 3273 | struct task_struct *curr = current; |
| 3274 | int i; |
| 3275 | |
| 3276 | for (i = 0; i < curr->lockdep_depth; i++) { |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3277 | struct held_lock *hlock = curr->held_locks + i; |
| 3278 | |
| 3279 | if (match_held_lock(hlock, lock)) |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 3280 | return 1; |
| 3281 | } |
| 3282 | |
| 3283 | return 0; |
| 3284 | } |
| 3285 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3286 | /* |
| 3287 | * Check whether we follow the irq-flags state precisely: |
| 3288 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 3289 | static void check_flags(unsigned long flags) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3290 | { |
Ingo Molnar | 992860e | 2008-07-14 10:28:38 +0200 | [diff] [blame] | 3291 | #if defined(CONFIG_PROVE_LOCKING) && defined(CONFIG_DEBUG_LOCKDEP) && \ |
| 3292 | defined(CONFIG_TRACE_IRQFLAGS) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3293 | if (!debug_locks) |
| 3294 | return; |
| 3295 | |
Ingo Molnar | 5f9fa8a | 2007-12-07 19:02:47 +0100 | [diff] [blame] | 3296 | if (irqs_disabled_flags(flags)) { |
| 3297 | if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) { |
| 3298 | printk("possible reason: unannotated irqs-off.\n"); |
| 3299 | } |
| 3300 | } else { |
| 3301 | if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) { |
| 3302 | printk("possible reason: unannotated irqs-on.\n"); |
| 3303 | } |
| 3304 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3305 | |
| 3306 | /* |
| 3307 | * We dont accurately track softirq state in e.g. |
| 3308 | * hardirq contexts (such as on 4KSTACKS), so only |
| 3309 | * check if not in hardirq contexts: |
| 3310 | */ |
| 3311 | if (!hardirq_count()) { |
| 3312 | if (softirq_count()) |
| 3313 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
| 3314 | else |
| 3315 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
| 3316 | } |
| 3317 | |
| 3318 | if (!debug_locks) |
| 3319 | print_irqtrace_events(current); |
| 3320 | #endif |
| 3321 | } |
| 3322 | |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3323 | void lock_set_class(struct lockdep_map *lock, const char *name, |
| 3324 | struct lock_class_key *key, unsigned int subclass, |
| 3325 | unsigned long ip) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3326 | { |
| 3327 | unsigned long flags; |
| 3328 | |
| 3329 | if (unlikely(current->lockdep_recursion)) |
| 3330 | return; |
| 3331 | |
| 3332 | raw_local_irq_save(flags); |
| 3333 | current->lockdep_recursion = 1; |
| 3334 | check_flags(flags); |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3335 | if (__lock_set_class(lock, name, key, subclass, ip)) |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3336 | check_chain_key(current); |
| 3337 | current->lockdep_recursion = 0; |
| 3338 | raw_local_irq_restore(flags); |
| 3339 | } |
Peter Zijlstra | 00ef9f7 | 2008-12-04 09:00:17 +0100 | [diff] [blame] | 3340 | EXPORT_SYMBOL_GPL(lock_set_class); |
Peter Zijlstra | 64aa348 | 2008-08-11 09:30:21 +0200 | [diff] [blame] | 3341 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3342 | /* |
| 3343 | * We are not always called with irqs disabled - do that here, |
| 3344 | * and also avoid lockdep recursion: |
| 3345 | */ |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 3346 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
Peter Zijlstra | 7531e2f | 2008-08-11 09:30:24 +0200 | [diff] [blame] | 3347 | int trylock, int read, int check, |
| 3348 | struct lockdep_map *nest_lock, unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3349 | { |
| 3350 | unsigned long flags; |
| 3351 | |
| 3352 | if (unlikely(current->lockdep_recursion)) |
| 3353 | return; |
| 3354 | |
| 3355 | raw_local_irq_save(flags); |
| 3356 | check_flags(flags); |
| 3357 | |
| 3358 | current->lockdep_recursion = 1; |
Frederic Weisbecker | db2c4c7 | 2010-02-02 23:34:40 +0100 | [diff] [blame] | 3359 | trace_lock_acquire(lock, subclass, trylock, read, check, nest_lock, ip); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3360 | __lock_acquire(lock, subclass, trylock, read, check, |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3361 | irqs_disabled_flags(flags), nest_lock, ip, 0); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3362 | current->lockdep_recursion = 0; |
| 3363 | raw_local_irq_restore(flags); |
| 3364 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3365 | EXPORT_SYMBOL_GPL(lock_acquire); |
| 3366 | |
Steven Rostedt | 1d09daa | 2008-05-12 21:20:55 +0200 | [diff] [blame] | 3367 | void lock_release(struct lockdep_map *lock, int nested, |
Steven Rostedt | 0764d23 | 2008-05-12 21:20:44 +0200 | [diff] [blame] | 3368 | unsigned long ip) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3369 | { |
| 3370 | unsigned long flags; |
| 3371 | |
| 3372 | if (unlikely(current->lockdep_recursion)) |
| 3373 | return; |
| 3374 | |
| 3375 | raw_local_irq_save(flags); |
| 3376 | check_flags(flags); |
| 3377 | current->lockdep_recursion = 1; |
Frederic Weisbecker | 9313543 | 2010-05-08 06:24:25 +0200 | [diff] [blame] | 3378 | trace_lock_release(lock, ip); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3379 | __lock_release(lock, nested, ip); |
| 3380 | current->lockdep_recursion = 0; |
| 3381 | raw_local_irq_restore(flags); |
| 3382 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3383 | EXPORT_SYMBOL_GPL(lock_release); |
| 3384 | |
Peter Zijlstra | f607c66 | 2009-07-20 19:16:29 +0200 | [diff] [blame] | 3385 | int lock_is_held(struct lockdep_map *lock) |
| 3386 | { |
| 3387 | unsigned long flags; |
| 3388 | int ret = 0; |
| 3389 | |
| 3390 | if (unlikely(current->lockdep_recursion)) |
| 3391 | return ret; |
| 3392 | |
| 3393 | raw_local_irq_save(flags); |
| 3394 | check_flags(flags); |
| 3395 | |
| 3396 | current->lockdep_recursion = 1; |
| 3397 | ret = __lock_is_held(lock); |
| 3398 | current->lockdep_recursion = 0; |
| 3399 | raw_local_irq_restore(flags); |
| 3400 | |
| 3401 | return ret; |
| 3402 | } |
| 3403 | EXPORT_SYMBOL_GPL(lock_is_held); |
| 3404 | |
Nick Piggin | cf40bd1 | 2009-01-21 08:12:39 +0100 | [diff] [blame] | 3405 | void lockdep_set_current_reclaim_state(gfp_t gfp_mask) |
| 3406 | { |
| 3407 | current->lockdep_reclaim_gfp = gfp_mask; |
| 3408 | } |
| 3409 | |
| 3410 | void lockdep_clear_current_reclaim_state(void) |
| 3411 | { |
| 3412 | current->lockdep_reclaim_gfp = 0; |
| 3413 | } |
| 3414 | |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3415 | #ifdef CONFIG_LOCK_STAT |
| 3416 | static int |
| 3417 | print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock, |
| 3418 | unsigned long ip) |
| 3419 | { |
| 3420 | if (!debug_locks_off()) |
| 3421 | return 0; |
| 3422 | if (debug_locks_silent) |
| 3423 | return 0; |
| 3424 | |
| 3425 | printk("\n=================================\n"); |
| 3426 | printk( "[ BUG: bad contention detected! ]\n"); |
| 3427 | printk( "---------------------------------\n"); |
| 3428 | printk("%s/%d is trying to contend lock (", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 3429 | curr->comm, task_pid_nr(curr)); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3430 | print_lockdep_cache(lock); |
| 3431 | printk(") at:\n"); |
| 3432 | print_ip_sym(ip); |
| 3433 | printk("but there are no locks held!\n"); |
| 3434 | printk("\nother info that might help us debug this:\n"); |
| 3435 | lockdep_print_held_locks(curr); |
| 3436 | |
| 3437 | printk("\nstack backtrace:\n"); |
| 3438 | dump_stack(); |
| 3439 | |
| 3440 | return 0; |
| 3441 | } |
| 3442 | |
| 3443 | static void |
| 3444 | __lock_contended(struct lockdep_map *lock, unsigned long ip) |
| 3445 | { |
| 3446 | struct task_struct *curr = current; |
| 3447 | struct held_lock *hlock, *prev_hlock; |
| 3448 | struct lock_class_stats *stats; |
| 3449 | unsigned int depth; |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 3450 | int i, contention_point, contending_point; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3451 | |
| 3452 | depth = curr->lockdep_depth; |
| 3453 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 3454 | return; |
| 3455 | |
| 3456 | prev_hlock = NULL; |
| 3457 | for (i = depth-1; i >= 0; i--) { |
| 3458 | hlock = curr->held_locks + i; |
| 3459 | /* |
| 3460 | * We must not cross into another context: |
| 3461 | */ |
| 3462 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) |
| 3463 | break; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3464 | if (match_held_lock(hlock, lock)) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3465 | goto found_it; |
| 3466 | prev_hlock = hlock; |
| 3467 | } |
| 3468 | print_lock_contention_bug(curr, lock, ip); |
| 3469 | return; |
| 3470 | |
| 3471 | found_it: |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3472 | if (hlock->instance != lock) |
| 3473 | return; |
| 3474 | |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 3475 | hlock->waittime_stamp = lockstat_clock(); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3476 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 3477 | contention_point = lock_point(hlock_class(hlock)->contention_point, ip); |
| 3478 | contending_point = lock_point(hlock_class(hlock)->contending_point, |
| 3479 | lock->ip); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3480 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3481 | stats = get_lock_stats(hlock_class(hlock)); |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 3482 | if (contention_point < LOCKSTAT_POINTS) |
| 3483 | stats->contention_point[contention_point]++; |
| 3484 | if (contending_point < LOCKSTAT_POINTS) |
| 3485 | stats->contending_point[contending_point]++; |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 3486 | if (lock->cpu != smp_processor_id()) |
| 3487 | stats->bounces[bounce_contended + !!hlock->read]++; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3488 | put_lock_stats(stats); |
| 3489 | } |
| 3490 | |
| 3491 | static void |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 3492 | __lock_acquired(struct lockdep_map *lock, unsigned long ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3493 | { |
| 3494 | struct task_struct *curr = current; |
| 3495 | struct held_lock *hlock, *prev_hlock; |
| 3496 | struct lock_class_stats *stats; |
| 3497 | unsigned int depth; |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 3498 | u64 now, waittime = 0; |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 3499 | int i, cpu; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3500 | |
| 3501 | depth = curr->lockdep_depth; |
| 3502 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 3503 | return; |
| 3504 | |
| 3505 | prev_hlock = NULL; |
| 3506 | for (i = depth-1; i >= 0; i--) { |
| 3507 | hlock = curr->held_locks + i; |
| 3508 | /* |
| 3509 | * We must not cross into another context: |
| 3510 | */ |
| 3511 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) |
| 3512 | break; |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3513 | if (match_held_lock(hlock, lock)) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3514 | goto found_it; |
| 3515 | prev_hlock = hlock; |
| 3516 | } |
| 3517 | print_lock_contention_bug(curr, lock, _RET_IP_); |
| 3518 | return; |
| 3519 | |
| 3520 | found_it: |
Peter Zijlstra | bb97a91 | 2009-07-20 19:15:35 +0200 | [diff] [blame] | 3521 | if (hlock->instance != lock) |
| 3522 | return; |
| 3523 | |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 3524 | cpu = smp_processor_id(); |
| 3525 | if (hlock->waittime_stamp) { |
Peter Zijlstra | 3365e779 | 2009-10-09 10:12:41 +0200 | [diff] [blame] | 3526 | now = lockstat_clock(); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 3527 | waittime = now - hlock->waittime_stamp; |
| 3528 | hlock->holdtime_stamp = now; |
| 3529 | } |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3530 | |
Frederic Weisbecker | 883a2a3 | 2010-05-08 06:16:11 +0200 | [diff] [blame] | 3531 | trace_lock_acquired(lock, ip); |
Frederic Weisbecker | 2062501 | 2009-04-06 01:49:33 +0200 | [diff] [blame] | 3532 | |
Dave Jones | f82b217 | 2008-08-11 09:30:23 +0200 | [diff] [blame] | 3533 | stats = get_lock_stats(hlock_class(hlock)); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 3534 | if (waittime) { |
| 3535 | if (hlock->read) |
| 3536 | lock_time_inc(&stats->read_waittime, waittime); |
| 3537 | else |
| 3538 | lock_time_inc(&stats->write_waittime, waittime); |
| 3539 | } |
| 3540 | if (lock->cpu != cpu) |
| 3541 | stats->bounces[bounce_acquired + !!hlock->read]++; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3542 | put_lock_stats(stats); |
Peter Zijlstra | 9664567 | 2007-07-19 01:49:00 -0700 | [diff] [blame] | 3543 | |
| 3544 | lock->cpu = cpu; |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 3545 | lock->ip = ip; |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3546 | } |
| 3547 | |
| 3548 | void lock_contended(struct lockdep_map *lock, unsigned long ip) |
| 3549 | { |
| 3550 | unsigned long flags; |
| 3551 | |
| 3552 | if (unlikely(!lock_stat)) |
| 3553 | return; |
| 3554 | |
| 3555 | if (unlikely(current->lockdep_recursion)) |
| 3556 | return; |
| 3557 | |
| 3558 | raw_local_irq_save(flags); |
| 3559 | check_flags(flags); |
| 3560 | current->lockdep_recursion = 1; |
Frederic Weisbecker | db2c4c7 | 2010-02-02 23:34:40 +0100 | [diff] [blame] | 3561 | trace_lock_contended(lock, ip); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3562 | __lock_contended(lock, ip); |
| 3563 | current->lockdep_recursion = 0; |
| 3564 | raw_local_irq_restore(flags); |
| 3565 | } |
| 3566 | EXPORT_SYMBOL_GPL(lock_contended); |
| 3567 | |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 3568 | void lock_acquired(struct lockdep_map *lock, unsigned long ip) |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3569 | { |
| 3570 | unsigned long flags; |
| 3571 | |
| 3572 | if (unlikely(!lock_stat)) |
| 3573 | return; |
| 3574 | |
| 3575 | if (unlikely(current->lockdep_recursion)) |
| 3576 | return; |
| 3577 | |
| 3578 | raw_local_irq_save(flags); |
| 3579 | check_flags(flags); |
| 3580 | current->lockdep_recursion = 1; |
Peter Zijlstra | c7e78cf | 2008-10-16 23:17:09 +0200 | [diff] [blame] | 3581 | __lock_acquired(lock, ip); |
Peter Zijlstra | f20786f | 2007-07-19 01:48:56 -0700 | [diff] [blame] | 3582 | current->lockdep_recursion = 0; |
| 3583 | raw_local_irq_restore(flags); |
| 3584 | } |
| 3585 | EXPORT_SYMBOL_GPL(lock_acquired); |
| 3586 | #endif |
| 3587 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3588 | /* |
| 3589 | * Used by the testsuite, sanitize the validator state |
| 3590 | * after a simulated failure: |
| 3591 | */ |
| 3592 | |
| 3593 | void lockdep_reset(void) |
| 3594 | { |
| 3595 | unsigned long flags; |
Ingo Molnar | 23d95a0 | 2006-12-13 00:34:40 -0800 | [diff] [blame] | 3596 | int i; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3597 | |
| 3598 | raw_local_irq_save(flags); |
| 3599 | current->curr_chain_key = 0; |
| 3600 | current->lockdep_depth = 0; |
| 3601 | current->lockdep_recursion = 0; |
| 3602 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); |
| 3603 | nr_hardirq_chains = 0; |
| 3604 | nr_softirq_chains = 0; |
| 3605 | nr_process_chains = 0; |
| 3606 | debug_locks = 1; |
Ingo Molnar | 23d95a0 | 2006-12-13 00:34:40 -0800 | [diff] [blame] | 3607 | for (i = 0; i < CHAINHASH_SIZE; i++) |
| 3608 | INIT_LIST_HEAD(chainhash_table + i); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3609 | raw_local_irq_restore(flags); |
| 3610 | } |
| 3611 | |
| 3612 | static void zap_class(struct lock_class *class) |
| 3613 | { |
| 3614 | int i; |
| 3615 | |
| 3616 | /* |
| 3617 | * Remove all dependencies this lock is |
| 3618 | * involved in: |
| 3619 | */ |
| 3620 | for (i = 0; i < nr_list_entries; i++) { |
| 3621 | if (list_entries[i].class == class) |
| 3622 | list_del_rcu(&list_entries[i].entry); |
| 3623 | } |
| 3624 | /* |
| 3625 | * Unhash the class and remove it from the all_lock_classes list: |
| 3626 | */ |
| 3627 | list_del_rcu(&class->hash_entry); |
| 3628 | list_del_rcu(&class->lock_entry); |
| 3629 | |
Rabin Vincent | 8bfe029 | 2008-08-11 09:30:26 +0200 | [diff] [blame] | 3630 | class->key = NULL; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3631 | } |
| 3632 | |
Arjan van de Ven | fabe874 | 2008-01-24 07:00:45 +0100 | [diff] [blame] | 3633 | static inline int within(const void *addr, void *start, unsigned long size) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3634 | { |
| 3635 | return addr >= start && addr < start + size; |
| 3636 | } |
| 3637 | |
| 3638 | void lockdep_free_key_range(void *start, unsigned long size) |
| 3639 | { |
| 3640 | struct lock_class *class, *next; |
| 3641 | struct list_head *head; |
| 3642 | unsigned long flags; |
| 3643 | int i; |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 3644 | int locked; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3645 | |
| 3646 | raw_local_irq_save(flags); |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 3647 | locked = graph_lock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3648 | |
| 3649 | /* |
| 3650 | * Unhash all classes that were created by this module: |
| 3651 | */ |
| 3652 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
| 3653 | head = classhash_table + i; |
| 3654 | if (list_empty(head)) |
| 3655 | continue; |
Arjan van de Ven | fabe874 | 2008-01-24 07:00:45 +0100 | [diff] [blame] | 3656 | list_for_each_entry_safe(class, next, head, hash_entry) { |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3657 | if (within(class->key, start, size)) |
| 3658 | zap_class(class); |
Arjan van de Ven | fabe874 | 2008-01-24 07:00:45 +0100 | [diff] [blame] | 3659 | else if (within(class->name, start, size)) |
| 3660 | zap_class(class); |
| 3661 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3662 | } |
| 3663 | |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 3664 | if (locked) |
| 3665 | graph_unlock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3666 | raw_local_irq_restore(flags); |
| 3667 | } |
| 3668 | |
| 3669 | void lockdep_reset_lock(struct lockdep_map *lock) |
| 3670 | { |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3671 | struct lock_class *class, *next; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3672 | struct list_head *head; |
| 3673 | unsigned long flags; |
| 3674 | int i, j; |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 3675 | int locked; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3676 | |
| 3677 | raw_local_irq_save(flags); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3678 | |
| 3679 | /* |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3680 | * Remove all classes this lock might have: |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3681 | */ |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3682 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { |
| 3683 | /* |
| 3684 | * If the class exists we look it up and zap it: |
| 3685 | */ |
| 3686 | class = look_up_lock_class(lock, j); |
| 3687 | if (class) |
| 3688 | zap_class(class); |
| 3689 | } |
| 3690 | /* |
| 3691 | * Debug check: in the end all mapped classes should |
| 3692 | * be gone. |
| 3693 | */ |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 3694 | locked = graph_lock(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3695 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
| 3696 | head = classhash_table + i; |
| 3697 | if (list_empty(head)) |
| 3698 | continue; |
| 3699 | list_for_each_entry_safe(class, next, head, hash_entry) { |
Hitoshi Mitake | 6201625 | 2010-10-05 18:01:51 +0900 | [diff] [blame] | 3700 | int match = 0; |
| 3701 | |
| 3702 | for (j = 0; j < NR_LOCKDEP_CACHING_CLASSES; j++) |
| 3703 | match |= class == lock->class_cache[j]; |
| 3704 | |
| 3705 | if (unlikely(match)) { |
Ingo Molnar | 74c383f | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 3706 | if (debug_locks_off_graph_unlock()) |
| 3707 | WARN_ON(1); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3708 | goto out_restore; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3709 | } |
| 3710 | } |
| 3711 | } |
Nick Piggin | 5a26db5 | 2008-01-16 09:51:58 +0100 | [diff] [blame] | 3712 | if (locked) |
| 3713 | graph_unlock(); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 3714 | |
| 3715 | out_restore: |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3716 | raw_local_irq_restore(flags); |
| 3717 | } |
| 3718 | |
Sam Ravnborg | 1499993 | 2007-02-28 20:12:31 -0800 | [diff] [blame] | 3719 | void lockdep_init(void) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3720 | { |
| 3721 | int i; |
| 3722 | |
| 3723 | /* |
| 3724 | * Some architectures have their own start_kernel() |
| 3725 | * code which calls lockdep_init(), while we also |
| 3726 | * call lockdep_init() from the start_kernel() itself, |
| 3727 | * and we want to initialize the hashes only once: |
| 3728 | */ |
| 3729 | if (lockdep_initialized) |
| 3730 | return; |
| 3731 | |
| 3732 | for (i = 0; i < CLASSHASH_SIZE; i++) |
| 3733 | INIT_LIST_HEAD(classhash_table + i); |
| 3734 | |
| 3735 | for (i = 0; i < CHAINHASH_SIZE; i++) |
| 3736 | INIT_LIST_HEAD(chainhash_table + i); |
| 3737 | |
| 3738 | lockdep_initialized = 1; |
| 3739 | } |
| 3740 | |
| 3741 | void __init lockdep_info(void) |
| 3742 | { |
| 3743 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); |
| 3744 | |
Li Zefan | b0788ca | 2008-11-21 15:57:32 +0800 | [diff] [blame] | 3745 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3746 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
| 3747 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); |
Li Zefan | b0788ca | 2008-11-21 15:57:32 +0800 | [diff] [blame] | 3748 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3749 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
| 3750 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); |
| 3751 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); |
| 3752 | |
| 3753 | printk(" memory used by lock dependency info: %lu kB\n", |
| 3754 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + |
| 3755 | sizeof(struct list_head) * CLASSHASH_SIZE + |
| 3756 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + |
| 3757 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + |
Ming Lei | 9062920 | 2009-08-02 21:43:36 +0800 | [diff] [blame] | 3758 | sizeof(struct list_head) * CHAINHASH_SIZE |
Ming Lei | 4dd861d | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 3759 | #ifdef CONFIG_PROVE_LOCKING |
Ming Lei | e351b66 | 2009-07-22 22:48:09 +0800 | [diff] [blame] | 3760 | + sizeof(struct circular_queue) |
Ming Lei | 4dd861d | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 3761 | #endif |
Ming Lei | 9062920 | 2009-08-02 21:43:36 +0800 | [diff] [blame] | 3762 | ) / 1024 |
Ming Lei | 4dd861d | 2009-07-16 15:44:29 +0200 | [diff] [blame] | 3763 | ); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3764 | |
| 3765 | printk(" per task-struct memory footprint: %lu bytes\n", |
| 3766 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); |
| 3767 | |
| 3768 | #ifdef CONFIG_DEBUG_LOCKDEP |
Johannes Berg | c71063c | 2007-07-19 01:49:02 -0700 | [diff] [blame] | 3769 | if (lockdep_init_error) { |
| 3770 | printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n"); |
| 3771 | printk("Call stack leading to lockdep invocation was:\n"); |
| 3772 | print_stack_trace(&lockdep_init_trace, 0); |
| 3773 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3774 | #endif |
| 3775 | } |
| 3776 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3777 | static void |
| 3778 | print_freed_lock_bug(struct task_struct *curr, const void *mem_from, |
Arjan van de Ven | 55794a4 | 2006-07-10 04:44:03 -0700 | [diff] [blame] | 3779 | const void *mem_to, struct held_lock *hlock) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3780 | { |
| 3781 | if (!debug_locks_off()) |
| 3782 | return; |
| 3783 | if (debug_locks_silent) |
| 3784 | return; |
| 3785 | |
| 3786 | printk("\n=========================\n"); |
| 3787 | printk( "[ BUG: held lock freed! ]\n"); |
| 3788 | printk( "-------------------------\n"); |
| 3789 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 3790 | curr->comm, task_pid_nr(curr), mem_from, mem_to-1); |
Arjan van de Ven | 55794a4 | 2006-07-10 04:44:03 -0700 | [diff] [blame] | 3791 | print_lock(hlock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3792 | lockdep_print_held_locks(curr); |
| 3793 | |
| 3794 | printk("\nstack backtrace:\n"); |
| 3795 | dump_stack(); |
| 3796 | } |
| 3797 | |
Oleg Nesterov | 5456178 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 3798 | static inline int not_in_range(const void* mem_from, unsigned long mem_len, |
| 3799 | const void* lock_from, unsigned long lock_len) |
| 3800 | { |
| 3801 | return lock_from + lock_len <= mem_from || |
| 3802 | mem_from + mem_len <= lock_from; |
| 3803 | } |
| 3804 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3805 | /* |
| 3806 | * Called when kernel memory is freed (or unmapped), or if a lock |
| 3807 | * is destroyed or reinitialized - this code checks whether there is |
| 3808 | * any held lock in the memory range of <from> to <to>: |
| 3809 | */ |
| 3810 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) |
| 3811 | { |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3812 | struct task_struct *curr = current; |
| 3813 | struct held_lock *hlock; |
| 3814 | unsigned long flags; |
| 3815 | int i; |
| 3816 | |
| 3817 | if (unlikely(!debug_locks)) |
| 3818 | return; |
| 3819 | |
| 3820 | local_irq_save(flags); |
| 3821 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 3822 | hlock = curr->held_locks + i; |
| 3823 | |
Oleg Nesterov | 5456178 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 3824 | if (not_in_range(mem_from, mem_len, hlock->instance, |
| 3825 | sizeof(*hlock->instance))) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3826 | continue; |
| 3827 | |
Oleg Nesterov | 5456178 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 3828 | print_freed_lock_bug(curr, mem_from, mem_from + mem_len, hlock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3829 | break; |
| 3830 | } |
| 3831 | local_irq_restore(flags); |
| 3832 | } |
Peter Zijlstra | ed07536 | 2006-12-06 20:35:24 -0800 | [diff] [blame] | 3833 | EXPORT_SYMBOL_GPL(debug_check_no_locks_freed); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3834 | |
| 3835 | static void print_held_locks_bug(struct task_struct *curr) |
| 3836 | { |
| 3837 | if (!debug_locks_off()) |
| 3838 | return; |
| 3839 | if (debug_locks_silent) |
| 3840 | return; |
| 3841 | |
| 3842 | printk("\n=====================================\n"); |
| 3843 | printk( "[ BUG: lock held at task exit time! ]\n"); |
| 3844 | printk( "-------------------------------------\n"); |
| 3845 | printk("%s/%d is exiting with locks still held!\n", |
Pavel Emelyanov | ba25f9d | 2007-10-18 23:40:40 -0700 | [diff] [blame] | 3846 | curr->comm, task_pid_nr(curr)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3847 | lockdep_print_held_locks(curr); |
| 3848 | |
| 3849 | printk("\nstack backtrace:\n"); |
| 3850 | dump_stack(); |
| 3851 | } |
| 3852 | |
| 3853 | void debug_check_no_locks_held(struct task_struct *task) |
| 3854 | { |
| 3855 | if (unlikely(task->lockdep_depth > 0)) |
| 3856 | print_held_locks_bug(task); |
| 3857 | } |
| 3858 | |
| 3859 | void debug_show_all_locks(void) |
| 3860 | { |
| 3861 | struct task_struct *g, *p; |
| 3862 | int count = 10; |
| 3863 | int unlock = 1; |
| 3864 | |
Jarek Poplawski | 9c35dd7 | 2007-03-22 00:11:28 -0800 | [diff] [blame] | 3865 | if (unlikely(!debug_locks)) { |
| 3866 | printk("INFO: lockdep is turned off.\n"); |
| 3867 | return; |
| 3868 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3869 | printk("\nShowing all locks held in the system:\n"); |
| 3870 | |
| 3871 | /* |
| 3872 | * Here we try to get the tasklist_lock as hard as possible, |
| 3873 | * if not successful after 2 seconds we ignore it (but keep |
| 3874 | * trying). This is to enable a debug printout even if a |
| 3875 | * tasklist_lock-holding task deadlocks or crashes. |
| 3876 | */ |
| 3877 | retry: |
| 3878 | if (!read_trylock(&tasklist_lock)) { |
| 3879 | if (count == 10) |
| 3880 | printk("hm, tasklist_lock locked, retrying... "); |
| 3881 | if (count) { |
| 3882 | count--; |
| 3883 | printk(" #%d", 10-count); |
| 3884 | mdelay(200); |
| 3885 | goto retry; |
| 3886 | } |
| 3887 | printk(" ignoring it.\n"); |
| 3888 | unlock = 0; |
qinghuang feng | 46fec7a | 2008-10-28 17:24:28 +0800 | [diff] [blame] | 3889 | } else { |
| 3890 | if (count != 10) |
| 3891 | printk(KERN_CONT " locked it.\n"); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3892 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3893 | |
| 3894 | do_each_thread(g, p) { |
Ingo Molnar | 8568487 | 2007-12-05 15:46:09 +0100 | [diff] [blame] | 3895 | /* |
| 3896 | * It's not reliable to print a task's held locks |
| 3897 | * if it's not sleeping (or if it's not the current |
| 3898 | * task): |
| 3899 | */ |
| 3900 | if (p->state == TASK_RUNNING && p != current) |
| 3901 | continue; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3902 | if (p->lockdep_depth) |
| 3903 | lockdep_print_held_locks(p); |
| 3904 | if (!unlock) |
| 3905 | if (read_trylock(&tasklist_lock)) |
| 3906 | unlock = 1; |
| 3907 | } while_each_thread(g, p); |
| 3908 | |
| 3909 | printk("\n"); |
| 3910 | printk("=============================================\n\n"); |
| 3911 | |
| 3912 | if (unlock) |
| 3913 | read_unlock(&tasklist_lock); |
| 3914 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3915 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
| 3916 | |
Ingo Molnar | 82a1fcb | 2008-01-25 21:08:02 +0100 | [diff] [blame] | 3917 | /* |
| 3918 | * Careful: only use this function if you are sure that |
| 3919 | * the task cannot run in parallel! |
| 3920 | */ |
John Kacur | f1b499f | 2010-08-05 17:10:53 +0200 | [diff] [blame] | 3921 | void debug_show_held_locks(struct task_struct *task) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3922 | { |
Jarek Poplawski | 9c35dd7 | 2007-03-22 00:11:28 -0800 | [diff] [blame] | 3923 | if (unlikely(!debug_locks)) { |
| 3924 | printk("INFO: lockdep is turned off.\n"); |
| 3925 | return; |
| 3926 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3927 | lockdep_print_held_locks(task); |
| 3928 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 3929 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
Peter Zijlstra | b351d16 | 2007-10-11 22:11:12 +0200 | [diff] [blame] | 3930 | |
| 3931 | void lockdep_sys_exit(void) |
| 3932 | { |
| 3933 | struct task_struct *curr = current; |
| 3934 | |
| 3935 | if (unlikely(curr->lockdep_depth)) { |
| 3936 | if (!debug_locks_off()) |
| 3937 | return; |
| 3938 | printk("\n================================================\n"); |
| 3939 | printk( "[ BUG: lock held when returning to user space! ]\n"); |
| 3940 | printk( "------------------------------------------------\n"); |
| 3941 | printk("%s/%d is leaving the kernel with locks still held!\n", |
| 3942 | curr->comm, curr->pid); |
| 3943 | lockdep_print_held_locks(curr); |
| 3944 | } |
| 3945 | } |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 3946 | |
| 3947 | void lockdep_rcu_dereference(const char *file, const int line) |
| 3948 | { |
| 3949 | struct task_struct *curr = current; |
| 3950 | |
Lai Jiangshan | 2b3fc35 | 2010-04-20 16:23:07 +0800 | [diff] [blame] | 3951 | #ifndef CONFIG_PROVE_RCU_REPEATEDLY |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 3952 | if (!debug_locks_off()) |
| 3953 | return; |
Lai Jiangshan | 2b3fc35 | 2010-04-20 16:23:07 +0800 | [diff] [blame] | 3954 | #endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */ |
| 3955 | /* Note: the following can be executed concurrently, so be careful. */ |
Paul E. McKenney | 056ba4a | 2010-02-25 14:06:46 -0800 | [diff] [blame] | 3956 | printk("\n===================================================\n"); |
| 3957 | printk( "[ INFO: suspicious rcu_dereference_check() usage. ]\n"); |
| 3958 | printk( "---------------------------------------------------\n"); |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 3959 | printk("%s:%d invoked rcu_dereference_check() without protection!\n", |
| 3960 | file, line); |
| 3961 | printk("\nother info that might help us debug this:\n\n"); |
Paul E. McKenney | cc5b83a | 2010-03-03 07:46:59 -0800 | [diff] [blame] | 3962 | printk("\nrcu_scheduler_active = %d, debug_locks = %d\n", rcu_scheduler_active, debug_locks); |
Paul E. McKenney | 0632eb3 | 2010-02-22 17:04:47 -0800 | [diff] [blame] | 3963 | lockdep_print_held_locks(curr); |
| 3964 | printk("\nstack backtrace:\n"); |
| 3965 | dump_stack(); |
| 3966 | } |
| 3967 | EXPORT_SYMBOL_GPL(lockdep_rcu_dereference); |