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 | * |
| 8 | * Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com> |
| 9 | * |
| 10 | * this code maps all the lock dependencies as they occur in a live kernel |
| 11 | * and will warn about the following classes of locking bugs: |
| 12 | * |
| 13 | * - lock inversion scenarios |
| 14 | * - circular lock dependencies |
| 15 | * - hardirq/softirq safe/unsafe locking bugs |
| 16 | * |
| 17 | * Bugs are reported even if the current locking scenario does not cause |
| 18 | * any deadlock at this point. |
| 19 | * |
| 20 | * I.e. if anytime in the past two locks were taken in a different order, |
| 21 | * even if it happened for another task, even if those were different |
| 22 | * locks (but of the same class as this lock), this code will detect it. |
| 23 | * |
| 24 | * Thanks to Arjan van de Ven for coming up with the initial idea of |
| 25 | * mapping lock dependencies runtime. |
| 26 | */ |
| 27 | #include <linux/mutex.h> |
| 28 | #include <linux/sched.h> |
| 29 | #include <linux/delay.h> |
| 30 | #include <linux/module.h> |
| 31 | #include <linux/proc_fs.h> |
| 32 | #include <linux/seq_file.h> |
| 33 | #include <linux/spinlock.h> |
| 34 | #include <linux/kallsyms.h> |
| 35 | #include <linux/interrupt.h> |
| 36 | #include <linux/stacktrace.h> |
| 37 | #include <linux/debug_locks.h> |
| 38 | #include <linux/irqflags.h> |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 39 | #include <linux/utsname.h> |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 40 | |
| 41 | #include <asm/sections.h> |
| 42 | |
| 43 | #include "lockdep_internals.h" |
| 44 | |
| 45 | /* |
| 46 | * hash_lock: protects the lockdep hashes and class/list/hash allocators. |
| 47 | * |
| 48 | * This is one of the rare exceptions where it's justified |
| 49 | * to use a raw spinlock - we really dont want the spinlock |
| 50 | * code to recurse back into the lockdep code. |
| 51 | */ |
| 52 | static raw_spinlock_t hash_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
| 53 | |
| 54 | static int lockdep_initialized; |
| 55 | |
| 56 | unsigned long nr_list_entries; |
| 57 | static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES]; |
| 58 | |
| 59 | /* |
| 60 | * Allocate a lockdep entry. (assumes hash_lock held, returns |
| 61 | * with NULL on failure) |
| 62 | */ |
| 63 | static struct lock_list *alloc_list_entry(void) |
| 64 | { |
| 65 | if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) { |
| 66 | __raw_spin_unlock(&hash_lock); |
| 67 | debug_locks_off(); |
| 68 | printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n"); |
| 69 | printk("turning off the locking correctness validator.\n"); |
| 70 | return NULL; |
| 71 | } |
| 72 | return list_entries + nr_list_entries++; |
| 73 | } |
| 74 | |
| 75 | /* |
| 76 | * All data structures here are protected by the global debug_lock. |
| 77 | * |
| 78 | * Mutex key structs only get allocated, once during bootup, and never |
| 79 | * get freed - this significantly simplifies the debugging code. |
| 80 | */ |
| 81 | unsigned long nr_lock_classes; |
| 82 | static struct lock_class lock_classes[MAX_LOCKDEP_KEYS]; |
| 83 | |
| 84 | /* |
| 85 | * We keep a global list of all lock classes. The list only grows, |
| 86 | * never shrinks. The list is only accessed with the lockdep |
| 87 | * spinlock lock held. |
| 88 | */ |
| 89 | LIST_HEAD(all_lock_classes); |
| 90 | |
| 91 | /* |
| 92 | * The lockdep classes are in a hash-table as well, for fast lookup: |
| 93 | */ |
| 94 | #define CLASSHASH_BITS (MAX_LOCKDEP_KEYS_BITS - 1) |
| 95 | #define CLASSHASH_SIZE (1UL << CLASSHASH_BITS) |
| 96 | #define CLASSHASH_MASK (CLASSHASH_SIZE - 1) |
| 97 | #define __classhashfn(key) ((((unsigned long)key >> CLASSHASH_BITS) + (unsigned long)key) & CLASSHASH_MASK) |
| 98 | #define classhashentry(key) (classhash_table + __classhashfn((key))) |
| 99 | |
| 100 | static struct list_head classhash_table[CLASSHASH_SIZE]; |
| 101 | |
| 102 | unsigned long nr_lock_chains; |
| 103 | static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS]; |
| 104 | |
| 105 | /* |
| 106 | * We put the lock dependency chains into a hash-table as well, to cache |
| 107 | * their existence: |
| 108 | */ |
| 109 | #define CHAINHASH_BITS (MAX_LOCKDEP_CHAINS_BITS-1) |
| 110 | #define CHAINHASH_SIZE (1UL << CHAINHASH_BITS) |
| 111 | #define CHAINHASH_MASK (CHAINHASH_SIZE - 1) |
| 112 | #define __chainhashfn(chain) \ |
| 113 | (((chain >> CHAINHASH_BITS) + chain) & CHAINHASH_MASK) |
| 114 | #define chainhashentry(chain) (chainhash_table + __chainhashfn((chain))) |
| 115 | |
| 116 | static struct list_head chainhash_table[CHAINHASH_SIZE]; |
| 117 | |
| 118 | /* |
| 119 | * The hash key of the lock dependency chains is a hash itself too: |
| 120 | * it's a hash of all locks taken up to that lock, including that lock. |
| 121 | * It's a 64-bit hash, because it's important for the keys to be |
| 122 | * unique. |
| 123 | */ |
| 124 | #define iterate_chain_key(key1, key2) \ |
Ingo Molnar | 03cbc35 | 2006-09-29 02:01:46 -0700 | [diff] [blame] | 125 | (((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \ |
| 126 | ((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 127 | (key2)) |
| 128 | |
| 129 | void lockdep_off(void) |
| 130 | { |
| 131 | current->lockdep_recursion++; |
| 132 | } |
| 133 | |
| 134 | EXPORT_SYMBOL(lockdep_off); |
| 135 | |
| 136 | void lockdep_on(void) |
| 137 | { |
| 138 | current->lockdep_recursion--; |
| 139 | } |
| 140 | |
| 141 | EXPORT_SYMBOL(lockdep_on); |
| 142 | |
| 143 | int lockdep_internal(void) |
| 144 | { |
| 145 | return current->lockdep_recursion != 0; |
| 146 | } |
| 147 | |
| 148 | EXPORT_SYMBOL(lockdep_internal); |
| 149 | |
| 150 | /* |
| 151 | * Debugging switches: |
| 152 | */ |
| 153 | |
| 154 | #define VERBOSE 0 |
| 155 | #ifdef VERBOSE |
| 156 | # define VERY_VERBOSE 0 |
| 157 | #endif |
| 158 | |
| 159 | #if VERBOSE |
| 160 | # define HARDIRQ_VERBOSE 1 |
| 161 | # define SOFTIRQ_VERBOSE 1 |
| 162 | #else |
| 163 | # define HARDIRQ_VERBOSE 0 |
| 164 | # define SOFTIRQ_VERBOSE 0 |
| 165 | #endif |
| 166 | |
| 167 | #if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE |
| 168 | /* |
| 169 | * Quick filtering for interesting events: |
| 170 | */ |
| 171 | static int class_filter(struct lock_class *class) |
| 172 | { |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 173 | #if 0 |
| 174 | /* Example */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 175 | if (class->name_version == 1 && |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 176 | !strcmp(class->name, "lockname")) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 177 | return 1; |
| 178 | if (class->name_version == 1 && |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 179 | !strcmp(class->name, "&struct->lockfield")) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 180 | return 1; |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 181 | #endif |
| 182 | /* Allow everything else. 0 would be filter everything else */ |
| 183 | return 1; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 184 | } |
| 185 | #endif |
| 186 | |
| 187 | static int verbose(struct lock_class *class) |
| 188 | { |
| 189 | #if VERBOSE |
| 190 | return class_filter(class); |
| 191 | #endif |
| 192 | return 0; |
| 193 | } |
| 194 | |
| 195 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 196 | |
| 197 | static int hardirq_verbose(struct lock_class *class) |
| 198 | { |
| 199 | #if HARDIRQ_VERBOSE |
| 200 | return class_filter(class); |
| 201 | #endif |
| 202 | return 0; |
| 203 | } |
| 204 | |
| 205 | static int softirq_verbose(struct lock_class *class) |
| 206 | { |
| 207 | #if SOFTIRQ_VERBOSE |
| 208 | return class_filter(class); |
| 209 | #endif |
| 210 | return 0; |
| 211 | } |
| 212 | |
| 213 | #endif |
| 214 | |
| 215 | /* |
| 216 | * Stack-trace: tightly packed array of stack backtrace |
| 217 | * addresses. Protected by the hash_lock. |
| 218 | */ |
| 219 | unsigned long nr_stack_trace_entries; |
| 220 | static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; |
| 221 | |
| 222 | static int save_trace(struct stack_trace *trace) |
| 223 | { |
| 224 | trace->nr_entries = 0; |
| 225 | trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries; |
| 226 | trace->entries = stack_trace + nr_stack_trace_entries; |
| 227 | |
Andi Kleen | 5a1b399 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 228 | trace->skip = 3; |
| 229 | trace->all_contexts = 0; |
| 230 | |
Andi Kleen | 3fa7c79 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 231 | /* Make sure to not recurse in case the the unwinder needs to tak |
| 232 | e locks. */ |
| 233 | lockdep_off(); |
Andi Kleen | 5a1b399 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 234 | save_stack_trace(trace, NULL); |
Andi Kleen | 3fa7c79 | 2006-09-26 10:52:34 +0200 | [diff] [blame] | 235 | lockdep_on(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 236 | |
| 237 | trace->max_entries = trace->nr_entries; |
| 238 | |
| 239 | nr_stack_trace_entries += trace->nr_entries; |
| 240 | if (DEBUG_LOCKS_WARN_ON(nr_stack_trace_entries > MAX_STACK_TRACE_ENTRIES)) |
| 241 | return 0; |
| 242 | |
| 243 | if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) { |
| 244 | __raw_spin_unlock(&hash_lock); |
| 245 | if (debug_locks_off()) { |
| 246 | printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n"); |
| 247 | printk("turning off the locking correctness validator.\n"); |
| 248 | dump_stack(); |
| 249 | } |
| 250 | return 0; |
| 251 | } |
| 252 | |
| 253 | return 1; |
| 254 | } |
| 255 | |
| 256 | unsigned int nr_hardirq_chains; |
| 257 | unsigned int nr_softirq_chains; |
| 258 | unsigned int nr_process_chains; |
| 259 | unsigned int max_lockdep_depth; |
| 260 | unsigned int max_recursion_depth; |
| 261 | |
| 262 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 263 | /* |
| 264 | * We cannot printk in early bootup code. Not even early_printk() |
| 265 | * might work. So we mark any initialization errors and printk |
| 266 | * about it later on, in lockdep_info(). |
| 267 | */ |
| 268 | static int lockdep_init_error; |
| 269 | |
| 270 | /* |
| 271 | * Various lockdep statistics: |
| 272 | */ |
| 273 | atomic_t chain_lookup_hits; |
| 274 | atomic_t chain_lookup_misses; |
| 275 | atomic_t hardirqs_on_events; |
| 276 | atomic_t hardirqs_off_events; |
| 277 | atomic_t redundant_hardirqs_on; |
| 278 | atomic_t redundant_hardirqs_off; |
| 279 | atomic_t softirqs_on_events; |
| 280 | atomic_t softirqs_off_events; |
| 281 | atomic_t redundant_softirqs_on; |
| 282 | atomic_t redundant_softirqs_off; |
| 283 | atomic_t nr_unused_locks; |
| 284 | atomic_t nr_cyclic_checks; |
| 285 | atomic_t nr_cyclic_check_recursions; |
| 286 | atomic_t nr_find_usage_forwards_checks; |
| 287 | atomic_t nr_find_usage_forwards_recursions; |
| 288 | atomic_t nr_find_usage_backwards_checks; |
| 289 | atomic_t nr_find_usage_backwards_recursions; |
| 290 | # define debug_atomic_inc(ptr) atomic_inc(ptr) |
| 291 | # define debug_atomic_dec(ptr) atomic_dec(ptr) |
| 292 | # define debug_atomic_read(ptr) atomic_read(ptr) |
| 293 | #else |
| 294 | # define debug_atomic_inc(ptr) do { } while (0) |
| 295 | # define debug_atomic_dec(ptr) do { } while (0) |
| 296 | # define debug_atomic_read(ptr) 0 |
| 297 | #endif |
| 298 | |
| 299 | /* |
| 300 | * Locking printouts: |
| 301 | */ |
| 302 | |
| 303 | static const char *usage_str[] = |
| 304 | { |
| 305 | [LOCK_USED] = "initial-use ", |
| 306 | [LOCK_USED_IN_HARDIRQ] = "in-hardirq-W", |
| 307 | [LOCK_USED_IN_SOFTIRQ] = "in-softirq-W", |
| 308 | [LOCK_ENABLED_SOFTIRQS] = "softirq-on-W", |
| 309 | [LOCK_ENABLED_HARDIRQS] = "hardirq-on-W", |
| 310 | [LOCK_USED_IN_HARDIRQ_READ] = "in-hardirq-R", |
| 311 | [LOCK_USED_IN_SOFTIRQ_READ] = "in-softirq-R", |
| 312 | [LOCK_ENABLED_SOFTIRQS_READ] = "softirq-on-R", |
| 313 | [LOCK_ENABLED_HARDIRQS_READ] = "hardirq-on-R", |
| 314 | }; |
| 315 | |
| 316 | const char * __get_key_name(struct lockdep_subclass_key *key, char *str) |
| 317 | { |
| 318 | unsigned long offs, size; |
| 319 | char *modname; |
| 320 | |
| 321 | return kallsyms_lookup((unsigned long)key, &size, &offs, &modname, str); |
| 322 | } |
| 323 | |
| 324 | void |
| 325 | get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4) |
| 326 | { |
| 327 | *c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.'; |
| 328 | |
| 329 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ) |
| 330 | *c1 = '+'; |
| 331 | else |
| 332 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS) |
| 333 | *c1 = '-'; |
| 334 | |
| 335 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ) |
| 336 | *c2 = '+'; |
| 337 | else |
| 338 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS) |
| 339 | *c2 = '-'; |
| 340 | |
| 341 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) |
| 342 | *c3 = '-'; |
| 343 | if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) { |
| 344 | *c3 = '+'; |
| 345 | if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ) |
| 346 | *c3 = '?'; |
| 347 | } |
| 348 | |
| 349 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) |
| 350 | *c4 = '-'; |
| 351 | if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) { |
| 352 | *c4 = '+'; |
| 353 | if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ) |
| 354 | *c4 = '?'; |
| 355 | } |
| 356 | } |
| 357 | |
| 358 | static void print_lock_name(struct lock_class *class) |
| 359 | { |
| 360 | char str[128], c1, c2, c3, c4; |
| 361 | const char *name; |
| 362 | |
| 363 | get_usage_chars(class, &c1, &c2, &c3, &c4); |
| 364 | |
| 365 | name = class->name; |
| 366 | if (!name) { |
| 367 | name = __get_key_name(class->key, str); |
| 368 | printk(" (%s", name); |
| 369 | } else { |
| 370 | printk(" (%s", name); |
| 371 | if (class->name_version > 1) |
| 372 | printk("#%d", class->name_version); |
| 373 | if (class->subclass) |
| 374 | printk("/%d", class->subclass); |
| 375 | } |
| 376 | printk("){%c%c%c%c}", c1, c2, c3, c4); |
| 377 | } |
| 378 | |
| 379 | static void print_lockdep_cache(struct lockdep_map *lock) |
| 380 | { |
| 381 | const char *name; |
| 382 | char str[128]; |
| 383 | |
| 384 | name = lock->name; |
| 385 | if (!name) |
| 386 | name = __get_key_name(lock->key->subkeys, str); |
| 387 | |
| 388 | printk("%s", name); |
| 389 | } |
| 390 | |
| 391 | static void print_lock(struct held_lock *hlock) |
| 392 | { |
| 393 | print_lock_name(hlock->class); |
| 394 | printk(", at: "); |
| 395 | print_ip_sym(hlock->acquire_ip); |
| 396 | } |
| 397 | |
| 398 | static void lockdep_print_held_locks(struct task_struct *curr) |
| 399 | { |
| 400 | int i, depth = curr->lockdep_depth; |
| 401 | |
| 402 | if (!depth) { |
| 403 | printk("no locks held by %s/%d.\n", curr->comm, curr->pid); |
| 404 | return; |
| 405 | } |
| 406 | printk("%d lock%s held by %s/%d:\n", |
| 407 | depth, depth > 1 ? "s" : "", curr->comm, curr->pid); |
| 408 | |
| 409 | for (i = 0; i < depth; i++) { |
| 410 | printk(" #%d: ", i); |
| 411 | print_lock(curr->held_locks + i); |
| 412 | } |
| 413 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 414 | |
| 415 | static void print_lock_class_header(struct lock_class *class, int depth) |
| 416 | { |
| 417 | int bit; |
| 418 | |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 419 | printk("%*s->", depth, ""); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 420 | print_lock_name(class); |
| 421 | printk(" ops: %lu", class->ops); |
| 422 | printk(" {\n"); |
| 423 | |
| 424 | for (bit = 0; bit < LOCK_USAGE_STATES; bit++) { |
| 425 | if (class->usage_mask & (1 << bit)) { |
| 426 | int len = depth; |
| 427 | |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 428 | len += printk("%*s %s", depth, "", usage_str[bit]); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 429 | len += printk(" at:\n"); |
| 430 | print_stack_trace(class->usage_traces + bit, len); |
| 431 | } |
| 432 | } |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 433 | printk("%*s }\n", depth, ""); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 434 | |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 435 | printk("%*s ... key at: ",depth,""); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 436 | print_ip_sym((unsigned long)class->key); |
| 437 | } |
| 438 | |
| 439 | /* |
| 440 | * printk all lock dependencies starting at <entry>: |
| 441 | */ |
| 442 | static void print_lock_dependencies(struct lock_class *class, int depth) |
| 443 | { |
| 444 | struct lock_list *entry; |
| 445 | |
| 446 | if (DEBUG_LOCKS_WARN_ON(depth >= 20)) |
| 447 | return; |
| 448 | |
| 449 | print_lock_class_header(class, depth); |
| 450 | |
| 451 | list_for_each_entry(entry, &class->locks_after, entry) { |
| 452 | DEBUG_LOCKS_WARN_ON(!entry->class); |
| 453 | print_lock_dependencies(entry->class, depth + 1); |
| 454 | |
Andi Kleen | f9829cc | 2006-07-10 04:44:01 -0700 | [diff] [blame] | 455 | printk("%*s ... acquired at:\n",depth,""); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 456 | print_stack_trace(&entry->trace, 2); |
| 457 | printk("\n"); |
| 458 | } |
| 459 | } |
| 460 | |
| 461 | /* |
| 462 | * Add a new dependency to the head of the list: |
| 463 | */ |
| 464 | static int add_lock_to_list(struct lock_class *class, struct lock_class *this, |
| 465 | struct list_head *head, unsigned long ip) |
| 466 | { |
| 467 | struct lock_list *entry; |
| 468 | /* |
| 469 | * Lock not present yet - get a new dependency struct and |
| 470 | * add it to the list: |
| 471 | */ |
| 472 | entry = alloc_list_entry(); |
| 473 | if (!entry) |
| 474 | return 0; |
| 475 | |
| 476 | entry->class = this; |
| 477 | save_trace(&entry->trace); |
| 478 | |
| 479 | /* |
| 480 | * Since we never remove from the dependency list, the list can |
| 481 | * be walked lockless by other CPUs, it's only allocation |
| 482 | * that must be protected by the spinlock. But this also means |
| 483 | * we must make new entries visible only once writes to the |
| 484 | * entry become visible - hence the RCU op: |
| 485 | */ |
| 486 | list_add_tail_rcu(&entry->entry, head); |
| 487 | |
| 488 | return 1; |
| 489 | } |
| 490 | |
| 491 | /* |
| 492 | * Recursive, forwards-direction lock-dependency checking, used for |
| 493 | * both noncyclic checking and for hardirq-unsafe/softirq-unsafe |
| 494 | * checking. |
| 495 | * |
| 496 | * (to keep the stackframe of the recursive functions small we |
| 497 | * use these global variables, and we also mark various helper |
| 498 | * functions as noinline.) |
| 499 | */ |
| 500 | static struct held_lock *check_source, *check_target; |
| 501 | |
| 502 | /* |
| 503 | * Print a dependency chain entry (this is only done when a deadlock |
| 504 | * has been detected): |
| 505 | */ |
| 506 | static noinline int |
| 507 | print_circular_bug_entry(struct lock_list *target, unsigned int depth) |
| 508 | { |
| 509 | if (debug_locks_silent) |
| 510 | return 0; |
| 511 | printk("\n-> #%u", depth); |
| 512 | print_lock_name(target->class); |
| 513 | printk(":\n"); |
| 514 | print_stack_trace(&target->trace, 6); |
| 515 | |
| 516 | return 0; |
| 517 | } |
| 518 | |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 519 | static void print_kernel_version(void) |
| 520 | { |
Serge E. Hallyn | 96b644b | 2006-10-02 02:18:13 -0700 | [diff] [blame] | 521 | printk("%s %.*s\n", init_utsname()->release, |
| 522 | (int)strcspn(init_utsname()->version, " "), |
| 523 | init_utsname()->version); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 524 | } |
| 525 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 526 | /* |
| 527 | * When a circular dependency is detected, print the |
| 528 | * header first: |
| 529 | */ |
| 530 | static noinline int |
| 531 | print_circular_bug_header(struct lock_list *entry, unsigned int depth) |
| 532 | { |
| 533 | struct task_struct *curr = current; |
| 534 | |
| 535 | __raw_spin_unlock(&hash_lock); |
| 536 | debug_locks_off(); |
| 537 | if (debug_locks_silent) |
| 538 | return 0; |
| 539 | |
| 540 | printk("\n=======================================================\n"); |
| 541 | printk( "[ INFO: possible circular locking dependency detected ]\n"); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 542 | print_kernel_version(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 543 | printk( "-------------------------------------------------------\n"); |
| 544 | printk("%s/%d is trying to acquire lock:\n", |
| 545 | curr->comm, curr->pid); |
| 546 | print_lock(check_source); |
| 547 | printk("\nbut task is already holding lock:\n"); |
| 548 | print_lock(check_target); |
| 549 | printk("\nwhich lock already depends on the new lock.\n\n"); |
| 550 | printk("\nthe existing dependency chain (in reverse order) is:\n"); |
| 551 | |
| 552 | print_circular_bug_entry(entry, depth); |
| 553 | |
| 554 | return 0; |
| 555 | } |
| 556 | |
| 557 | static noinline int print_circular_bug_tail(void) |
| 558 | { |
| 559 | struct task_struct *curr = current; |
| 560 | struct lock_list this; |
| 561 | |
| 562 | if (debug_locks_silent) |
| 563 | return 0; |
| 564 | |
| 565 | this.class = check_source->class; |
| 566 | save_trace(&this.trace); |
| 567 | print_circular_bug_entry(&this, 0); |
| 568 | |
| 569 | printk("\nother info that might help us debug this:\n\n"); |
| 570 | lockdep_print_held_locks(curr); |
| 571 | |
| 572 | printk("\nstack backtrace:\n"); |
| 573 | dump_stack(); |
| 574 | |
| 575 | return 0; |
| 576 | } |
| 577 | |
Ingo Molnar | ca268c6 | 2006-10-17 00:09:28 -0700 | [diff] [blame] | 578 | #define RECURSION_LIMIT 40 |
| 579 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 580 | static int noinline print_infinite_recursion_bug(void) |
| 581 | { |
| 582 | __raw_spin_unlock(&hash_lock); |
| 583 | DEBUG_LOCKS_WARN_ON(1); |
| 584 | |
| 585 | return 0; |
| 586 | } |
| 587 | |
| 588 | /* |
| 589 | * Prove that the dependency graph starting at <entry> can not |
| 590 | * lead to <target>. Print an error and return 0 if it does. |
| 591 | */ |
| 592 | static noinline int |
| 593 | check_noncircular(struct lock_class *source, unsigned int depth) |
| 594 | { |
| 595 | struct lock_list *entry; |
| 596 | |
| 597 | debug_atomic_inc(&nr_cyclic_check_recursions); |
| 598 | if (depth > max_recursion_depth) |
| 599 | max_recursion_depth = depth; |
Ingo Molnar | ca268c6 | 2006-10-17 00:09:28 -0700 | [diff] [blame] | 600 | if (depth >= RECURSION_LIMIT) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 601 | return print_infinite_recursion_bug(); |
| 602 | /* |
| 603 | * Check this lock's dependency list: |
| 604 | */ |
| 605 | list_for_each_entry(entry, &source->locks_after, entry) { |
| 606 | if (entry->class == check_target->class) |
| 607 | return print_circular_bug_header(entry, depth+1); |
| 608 | debug_atomic_inc(&nr_cyclic_checks); |
| 609 | if (!check_noncircular(entry->class, depth+1)) |
| 610 | return print_circular_bug_entry(entry, depth+1); |
| 611 | } |
| 612 | return 1; |
| 613 | } |
| 614 | |
| 615 | static int very_verbose(struct lock_class *class) |
| 616 | { |
| 617 | #if VERY_VERBOSE |
| 618 | return class_filter(class); |
| 619 | #endif |
| 620 | return 0; |
| 621 | } |
| 622 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 623 | |
| 624 | /* |
| 625 | * Forwards and backwards subgraph searching, for the purposes of |
| 626 | * proving that two subgraphs can be connected by a new dependency |
| 627 | * without creating any illegal irq-safe -> irq-unsafe lock dependency. |
| 628 | */ |
| 629 | static enum lock_usage_bit find_usage_bit; |
| 630 | static struct lock_class *forwards_match, *backwards_match; |
| 631 | |
| 632 | /* |
| 633 | * Find a node in the forwards-direction dependency sub-graph starting |
| 634 | * at <source> that matches <find_usage_bit>. |
| 635 | * |
| 636 | * Return 2 if such a node exists in the subgraph, and put that node |
| 637 | * into <forwards_match>. |
| 638 | * |
| 639 | * Return 1 otherwise and keep <forwards_match> unchanged. |
| 640 | * Return 0 on error. |
| 641 | */ |
| 642 | static noinline int |
| 643 | find_usage_forwards(struct lock_class *source, unsigned int depth) |
| 644 | { |
| 645 | struct lock_list *entry; |
| 646 | int ret; |
| 647 | |
| 648 | if (depth > max_recursion_depth) |
| 649 | max_recursion_depth = depth; |
Ingo Molnar | ca268c6 | 2006-10-17 00:09:28 -0700 | [diff] [blame] | 650 | if (depth >= RECURSION_LIMIT) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 651 | return print_infinite_recursion_bug(); |
| 652 | |
| 653 | debug_atomic_inc(&nr_find_usage_forwards_checks); |
| 654 | if (source->usage_mask & (1 << find_usage_bit)) { |
| 655 | forwards_match = source; |
| 656 | return 2; |
| 657 | } |
| 658 | |
| 659 | /* |
| 660 | * Check this lock's dependency list: |
| 661 | */ |
| 662 | list_for_each_entry(entry, &source->locks_after, entry) { |
| 663 | debug_atomic_inc(&nr_find_usage_forwards_recursions); |
| 664 | ret = find_usage_forwards(entry->class, depth+1); |
| 665 | if (ret == 2 || ret == 0) |
| 666 | return ret; |
| 667 | } |
| 668 | return 1; |
| 669 | } |
| 670 | |
| 671 | /* |
| 672 | * Find a node in the backwards-direction dependency sub-graph starting |
| 673 | * at <source> that matches <find_usage_bit>. |
| 674 | * |
| 675 | * Return 2 if such a node exists in the subgraph, and put that node |
| 676 | * into <backwards_match>. |
| 677 | * |
| 678 | * Return 1 otherwise and keep <backwards_match> unchanged. |
| 679 | * Return 0 on error. |
| 680 | */ |
| 681 | static noinline int |
| 682 | find_usage_backwards(struct lock_class *source, unsigned int depth) |
| 683 | { |
| 684 | struct lock_list *entry; |
| 685 | int ret; |
| 686 | |
| 687 | if (depth > max_recursion_depth) |
| 688 | max_recursion_depth = depth; |
Ingo Molnar | ca268c6 | 2006-10-17 00:09:28 -0700 | [diff] [blame] | 689 | if (depth >= RECURSION_LIMIT) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 690 | return print_infinite_recursion_bug(); |
| 691 | |
| 692 | debug_atomic_inc(&nr_find_usage_backwards_checks); |
| 693 | if (source->usage_mask & (1 << find_usage_bit)) { |
| 694 | backwards_match = source; |
| 695 | return 2; |
| 696 | } |
| 697 | |
| 698 | /* |
| 699 | * Check this lock's dependency list: |
| 700 | */ |
| 701 | list_for_each_entry(entry, &source->locks_before, entry) { |
| 702 | debug_atomic_inc(&nr_find_usage_backwards_recursions); |
| 703 | ret = find_usage_backwards(entry->class, depth+1); |
| 704 | if (ret == 2 || ret == 0) |
| 705 | return ret; |
| 706 | } |
| 707 | return 1; |
| 708 | } |
| 709 | |
| 710 | static int |
| 711 | print_bad_irq_dependency(struct task_struct *curr, |
| 712 | struct held_lock *prev, |
| 713 | struct held_lock *next, |
| 714 | enum lock_usage_bit bit1, |
| 715 | enum lock_usage_bit bit2, |
| 716 | const char *irqclass) |
| 717 | { |
| 718 | __raw_spin_unlock(&hash_lock); |
| 719 | debug_locks_off(); |
| 720 | if (debug_locks_silent) |
| 721 | return 0; |
| 722 | |
| 723 | printk("\n======================================================\n"); |
| 724 | printk( "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n", |
| 725 | irqclass, irqclass); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 726 | print_kernel_version(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 727 | printk( "------------------------------------------------------\n"); |
| 728 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n", |
| 729 | curr->comm, curr->pid, |
| 730 | curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT, |
| 731 | curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT, |
| 732 | curr->hardirqs_enabled, |
| 733 | curr->softirqs_enabled); |
| 734 | print_lock(next); |
| 735 | |
| 736 | printk("\nand this task is already holding:\n"); |
| 737 | print_lock(prev); |
| 738 | printk("which would create a new lock dependency:\n"); |
| 739 | print_lock_name(prev->class); |
| 740 | printk(" ->"); |
| 741 | print_lock_name(next->class); |
| 742 | printk("\n"); |
| 743 | |
| 744 | printk("\nbut this new dependency connects a %s-irq-safe lock:\n", |
| 745 | irqclass); |
| 746 | print_lock_name(backwards_match); |
| 747 | printk("\n... which became %s-irq-safe at:\n", irqclass); |
| 748 | |
| 749 | print_stack_trace(backwards_match->usage_traces + bit1, 1); |
| 750 | |
| 751 | printk("\nto a %s-irq-unsafe lock:\n", irqclass); |
| 752 | print_lock_name(forwards_match); |
| 753 | printk("\n... which became %s-irq-unsafe at:\n", irqclass); |
| 754 | printk("..."); |
| 755 | |
| 756 | print_stack_trace(forwards_match->usage_traces + bit2, 1); |
| 757 | |
| 758 | printk("\nother info that might help us debug this:\n\n"); |
| 759 | lockdep_print_held_locks(curr); |
| 760 | |
| 761 | printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); |
| 762 | print_lock_dependencies(backwards_match, 0); |
| 763 | |
| 764 | printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); |
| 765 | print_lock_dependencies(forwards_match, 0); |
| 766 | |
| 767 | printk("\nstack backtrace:\n"); |
| 768 | dump_stack(); |
| 769 | |
| 770 | return 0; |
| 771 | } |
| 772 | |
| 773 | static int |
| 774 | check_usage(struct task_struct *curr, struct held_lock *prev, |
| 775 | struct held_lock *next, enum lock_usage_bit bit_backwards, |
| 776 | enum lock_usage_bit bit_forwards, const char *irqclass) |
| 777 | { |
| 778 | int ret; |
| 779 | |
| 780 | find_usage_bit = bit_backwards; |
| 781 | /* fills in <backwards_match> */ |
| 782 | ret = find_usage_backwards(prev->class, 0); |
| 783 | if (!ret || ret == 1) |
| 784 | return ret; |
| 785 | |
| 786 | find_usage_bit = bit_forwards; |
| 787 | ret = find_usage_forwards(next->class, 0); |
| 788 | if (!ret || ret == 1) |
| 789 | return ret; |
| 790 | /* ret == 2 */ |
| 791 | return print_bad_irq_dependency(curr, prev, next, |
| 792 | bit_backwards, bit_forwards, irqclass); |
| 793 | } |
| 794 | |
| 795 | #endif |
| 796 | |
| 797 | static int |
| 798 | print_deadlock_bug(struct task_struct *curr, struct held_lock *prev, |
| 799 | struct held_lock *next) |
| 800 | { |
| 801 | debug_locks_off(); |
| 802 | __raw_spin_unlock(&hash_lock); |
| 803 | if (debug_locks_silent) |
| 804 | return 0; |
| 805 | |
| 806 | printk("\n=============================================\n"); |
| 807 | printk( "[ INFO: possible recursive locking detected ]\n"); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 808 | print_kernel_version(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 809 | printk( "---------------------------------------------\n"); |
| 810 | printk("%s/%d is trying to acquire lock:\n", |
| 811 | curr->comm, curr->pid); |
| 812 | print_lock(next); |
| 813 | printk("\nbut task is already holding lock:\n"); |
| 814 | print_lock(prev); |
| 815 | |
| 816 | printk("\nother info that might help us debug this:\n"); |
| 817 | lockdep_print_held_locks(curr); |
| 818 | |
| 819 | printk("\nstack backtrace:\n"); |
| 820 | dump_stack(); |
| 821 | |
| 822 | return 0; |
| 823 | } |
| 824 | |
| 825 | /* |
| 826 | * Check whether we are holding such a class already. |
| 827 | * |
| 828 | * (Note that this has to be done separately, because the graph cannot |
| 829 | * detect such classes of deadlocks.) |
| 830 | * |
| 831 | * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read |
| 832 | */ |
| 833 | static int |
| 834 | check_deadlock(struct task_struct *curr, struct held_lock *next, |
| 835 | struct lockdep_map *next_instance, int read) |
| 836 | { |
| 837 | struct held_lock *prev; |
| 838 | int i; |
| 839 | |
| 840 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 841 | prev = curr->held_locks + i; |
| 842 | if (prev->class != next->class) |
| 843 | continue; |
| 844 | /* |
| 845 | * Allow read-after-read recursion of the same |
Ingo Molnar | 6c9076e | 2006-07-03 00:24:51 -0700 | [diff] [blame] | 846 | * lock class (i.e. read_lock(lock)+read_lock(lock)): |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 847 | */ |
Ingo Molnar | 6c9076e | 2006-07-03 00:24:51 -0700 | [diff] [blame] | 848 | if ((read == 2) && prev->read) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 849 | return 2; |
| 850 | return print_deadlock_bug(curr, prev, next); |
| 851 | } |
| 852 | return 1; |
| 853 | } |
| 854 | |
| 855 | /* |
| 856 | * There was a chain-cache miss, and we are about to add a new dependency |
| 857 | * to a previous lock. We recursively validate the following rules: |
| 858 | * |
| 859 | * - would the adding of the <prev> -> <next> dependency create a |
| 860 | * circular dependency in the graph? [== circular deadlock] |
| 861 | * |
| 862 | * - does the new prev->next dependency connect any hardirq-safe lock |
| 863 | * (in the full backwards-subgraph starting at <prev>) with any |
| 864 | * hardirq-unsafe lock (in the full forwards-subgraph starting at |
| 865 | * <next>)? [== illegal lock inversion with hardirq contexts] |
| 866 | * |
| 867 | * - does the new prev->next dependency connect any softirq-safe lock |
| 868 | * (in the full backwards-subgraph starting at <prev>) with any |
| 869 | * softirq-unsafe lock (in the full forwards-subgraph starting at |
| 870 | * <next>)? [== illegal lock inversion with softirq contexts] |
| 871 | * |
| 872 | * any of these scenarios could lead to a deadlock. |
| 873 | * |
| 874 | * Then if all the validations pass, we add the forwards and backwards |
| 875 | * dependency. |
| 876 | */ |
| 877 | static int |
| 878 | check_prev_add(struct task_struct *curr, struct held_lock *prev, |
| 879 | struct held_lock *next) |
| 880 | { |
| 881 | struct lock_list *entry; |
| 882 | int ret; |
| 883 | |
| 884 | /* |
| 885 | * Prove that the new <prev> -> <next> dependency would not |
| 886 | * create a circular dependency in the graph. (We do this by |
| 887 | * forward-recursing into the graph starting at <next>, and |
| 888 | * checking whether we can reach <prev>.) |
| 889 | * |
| 890 | * We are using global variables to control the recursion, to |
| 891 | * keep the stackframe size of the recursive functions low: |
| 892 | */ |
| 893 | check_source = next; |
| 894 | check_target = prev; |
| 895 | if (!(check_noncircular(next->class, 0))) |
| 896 | return print_circular_bug_tail(); |
| 897 | |
| 898 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 899 | /* |
| 900 | * Prove that the new dependency does not connect a hardirq-safe |
| 901 | * lock with a hardirq-unsafe lock - to achieve this we search |
| 902 | * the backwards-subgraph starting at <prev>, and the |
| 903 | * forwards-subgraph starting at <next>: |
| 904 | */ |
| 905 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ, |
| 906 | LOCK_ENABLED_HARDIRQS, "hard")) |
| 907 | return 0; |
| 908 | |
| 909 | /* |
| 910 | * Prove that the new dependency does not connect a hardirq-safe-read |
| 911 | * lock with a hardirq-unsafe lock - to achieve this we search |
| 912 | * the backwards-subgraph starting at <prev>, and the |
| 913 | * forwards-subgraph starting at <next>: |
| 914 | */ |
| 915 | if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ, |
| 916 | LOCK_ENABLED_HARDIRQS, "hard-read")) |
| 917 | return 0; |
| 918 | |
| 919 | /* |
| 920 | * Prove that the new dependency does not connect a softirq-safe |
| 921 | * lock with a softirq-unsafe lock - to achieve this we search |
| 922 | * the backwards-subgraph starting at <prev>, and the |
| 923 | * forwards-subgraph starting at <next>: |
| 924 | */ |
| 925 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ, |
| 926 | LOCK_ENABLED_SOFTIRQS, "soft")) |
| 927 | return 0; |
| 928 | /* |
| 929 | * Prove that the new dependency does not connect a softirq-safe-read |
| 930 | * lock with a softirq-unsafe lock - to achieve this we search |
| 931 | * the backwards-subgraph starting at <prev>, and the |
| 932 | * forwards-subgraph starting at <next>: |
| 933 | */ |
| 934 | if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ, |
| 935 | LOCK_ENABLED_SOFTIRQS, "soft")) |
| 936 | return 0; |
| 937 | #endif |
| 938 | /* |
| 939 | * For recursive read-locks we do all the dependency checks, |
| 940 | * but we dont store read-triggered dependencies (only |
| 941 | * write-triggered dependencies). This ensures that only the |
| 942 | * write-side dependencies matter, and that if for example a |
| 943 | * write-lock never takes any other locks, then the reads are |
| 944 | * equivalent to a NOP. |
| 945 | */ |
| 946 | if (next->read == 2 || prev->read == 2) |
| 947 | return 1; |
| 948 | /* |
| 949 | * Is the <prev> -> <next> dependency already present? |
| 950 | * |
| 951 | * (this may occur even though this is a new chain: consider |
| 952 | * e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3 |
| 953 | * chains - the second one will be new, but L1 already has |
| 954 | * L2 added to its dependency list, due to the first chain.) |
| 955 | */ |
| 956 | list_for_each_entry(entry, &prev->class->locks_after, entry) { |
| 957 | if (entry->class == next->class) |
| 958 | return 2; |
| 959 | } |
| 960 | |
| 961 | /* |
| 962 | * Ok, all validations passed, add the new lock |
| 963 | * to the previous lock's dependency list: |
| 964 | */ |
| 965 | ret = add_lock_to_list(prev->class, next->class, |
| 966 | &prev->class->locks_after, next->acquire_ip); |
| 967 | if (!ret) |
| 968 | return 0; |
| 969 | /* |
| 970 | * Return value of 2 signals 'dependency already added', |
| 971 | * in that case we dont have to add the backlink either. |
| 972 | */ |
| 973 | if (ret == 2) |
| 974 | return 2; |
| 975 | ret = add_lock_to_list(next->class, prev->class, |
| 976 | &next->class->locks_before, next->acquire_ip); |
| 977 | |
| 978 | /* |
| 979 | * Debugging printouts: |
| 980 | */ |
| 981 | if (verbose(prev->class) || verbose(next->class)) { |
| 982 | __raw_spin_unlock(&hash_lock); |
| 983 | printk("\n new dependency: "); |
| 984 | print_lock_name(prev->class); |
| 985 | printk(" => "); |
| 986 | print_lock_name(next->class); |
| 987 | printk("\n"); |
| 988 | dump_stack(); |
| 989 | __raw_spin_lock(&hash_lock); |
| 990 | } |
| 991 | return 1; |
| 992 | } |
| 993 | |
| 994 | /* |
| 995 | * Add the dependency to all directly-previous locks that are 'relevant'. |
| 996 | * The ones that are relevant are (in increasing distance from curr): |
| 997 | * all consecutive trylock entries and the final non-trylock entry - or |
| 998 | * the end of this context's lock-chain - whichever comes first. |
| 999 | */ |
| 1000 | static int |
| 1001 | check_prevs_add(struct task_struct *curr, struct held_lock *next) |
| 1002 | { |
| 1003 | int depth = curr->lockdep_depth; |
| 1004 | struct held_lock *hlock; |
| 1005 | |
| 1006 | /* |
| 1007 | * Debugging checks. |
| 1008 | * |
| 1009 | * Depth must not be zero for a non-head lock: |
| 1010 | */ |
| 1011 | if (!depth) |
| 1012 | goto out_bug; |
| 1013 | /* |
| 1014 | * At least two relevant locks must exist for this |
| 1015 | * to be a head: |
| 1016 | */ |
| 1017 | if (curr->held_locks[depth].irq_context != |
| 1018 | curr->held_locks[depth-1].irq_context) |
| 1019 | goto out_bug; |
| 1020 | |
| 1021 | for (;;) { |
| 1022 | hlock = curr->held_locks + depth-1; |
| 1023 | /* |
| 1024 | * Only non-recursive-read entries get new dependencies |
| 1025 | * added: |
| 1026 | */ |
| 1027 | if (hlock->read != 2) { |
| 1028 | check_prev_add(curr, hlock, next); |
| 1029 | /* |
| 1030 | * Stop after the first non-trylock entry, |
| 1031 | * as non-trylock entries have added their |
| 1032 | * own direct dependencies already, so this |
| 1033 | * lock is connected to them indirectly: |
| 1034 | */ |
| 1035 | if (!hlock->trylock) |
| 1036 | break; |
| 1037 | } |
| 1038 | depth--; |
| 1039 | /* |
| 1040 | * End of lock-stack? |
| 1041 | */ |
| 1042 | if (!depth) |
| 1043 | break; |
| 1044 | /* |
| 1045 | * Stop the search if we cross into another context: |
| 1046 | */ |
| 1047 | if (curr->held_locks[depth].irq_context != |
| 1048 | curr->held_locks[depth-1].irq_context) |
| 1049 | break; |
| 1050 | } |
| 1051 | return 1; |
| 1052 | out_bug: |
| 1053 | __raw_spin_unlock(&hash_lock); |
| 1054 | DEBUG_LOCKS_WARN_ON(1); |
| 1055 | |
| 1056 | return 0; |
| 1057 | } |
| 1058 | |
| 1059 | |
| 1060 | /* |
| 1061 | * Is this the address of a static object: |
| 1062 | */ |
| 1063 | static int static_obj(void *obj) |
| 1064 | { |
| 1065 | unsigned long start = (unsigned long) &_stext, |
| 1066 | end = (unsigned long) &_end, |
| 1067 | addr = (unsigned long) obj; |
| 1068 | #ifdef CONFIG_SMP |
| 1069 | int i; |
| 1070 | #endif |
| 1071 | |
| 1072 | /* |
| 1073 | * static variable? |
| 1074 | */ |
| 1075 | if ((addr >= start) && (addr < end)) |
| 1076 | return 1; |
| 1077 | |
| 1078 | #ifdef CONFIG_SMP |
| 1079 | /* |
| 1080 | * percpu var? |
| 1081 | */ |
| 1082 | for_each_possible_cpu(i) { |
| 1083 | start = (unsigned long) &__per_cpu_start + per_cpu_offset(i); |
Ingo Molnar | 1ff5683 | 2006-11-17 19:57:22 +0100 | [diff] [blame] | 1084 | end = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM |
| 1085 | + per_cpu_offset(i); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1086 | |
| 1087 | if ((addr >= start) && (addr < end)) |
| 1088 | return 1; |
| 1089 | } |
| 1090 | #endif |
| 1091 | |
| 1092 | /* |
| 1093 | * module var? |
| 1094 | */ |
| 1095 | return is_module_address(addr); |
| 1096 | } |
| 1097 | |
| 1098 | /* |
| 1099 | * To make lock name printouts unique, we calculate a unique |
| 1100 | * class->name_version generation counter: |
| 1101 | */ |
| 1102 | static int count_matching_names(struct lock_class *new_class) |
| 1103 | { |
| 1104 | struct lock_class *class; |
| 1105 | int count = 0; |
| 1106 | |
| 1107 | if (!new_class->name) |
| 1108 | return 0; |
| 1109 | |
| 1110 | list_for_each_entry(class, &all_lock_classes, lock_entry) { |
| 1111 | if (new_class->key - new_class->subclass == class->key) |
| 1112 | return class->name_version; |
| 1113 | if (class->name && !strcmp(class->name, new_class->name)) |
| 1114 | count = max(count, class->name_version); |
| 1115 | } |
| 1116 | |
| 1117 | return count + 1; |
| 1118 | } |
| 1119 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1120 | /* |
| 1121 | * Register a lock's class in the hash-table, if the class is not present |
| 1122 | * yet. Otherwise we look it up. We cache the result in the lock object |
| 1123 | * itself, so actual lookup of the hash should be once per lock object. |
| 1124 | */ |
| 1125 | static inline struct lock_class * |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1126 | look_up_lock_class(struct lockdep_map *lock, unsigned int subclass) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1127 | { |
| 1128 | struct lockdep_subclass_key *key; |
| 1129 | struct list_head *hash_head; |
| 1130 | struct lock_class *class; |
| 1131 | |
| 1132 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 1133 | /* |
| 1134 | * If the architecture calls into lockdep before initializing |
| 1135 | * the hashes then we'll warn about it later. (we cannot printk |
| 1136 | * right now) |
| 1137 | */ |
| 1138 | if (unlikely(!lockdep_initialized)) { |
| 1139 | lockdep_init(); |
| 1140 | lockdep_init_error = 1; |
| 1141 | } |
| 1142 | #endif |
| 1143 | |
| 1144 | /* |
| 1145 | * Static locks do not have their class-keys yet - for them the key |
| 1146 | * is the lock object itself: |
| 1147 | */ |
| 1148 | if (unlikely(!lock->key)) |
| 1149 | lock->key = (void *)lock; |
| 1150 | |
| 1151 | /* |
| 1152 | * NOTE: the class-key must be unique. For dynamic locks, a static |
| 1153 | * lock_class_key variable is passed in through the mutex_init() |
| 1154 | * (or spin_lock_init()) call - which acts as the key. For static |
| 1155 | * locks we use the lock object itself as the key. |
| 1156 | */ |
Alexey Dobriyan | 3dc3099 | 2006-10-11 01:22:06 -0700 | [diff] [blame] | 1157 | BUILD_BUG_ON(sizeof(struct lock_class_key) > sizeof(struct lock_class)); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1158 | |
| 1159 | key = lock->key->subkeys + subclass; |
| 1160 | |
| 1161 | hash_head = classhashentry(key); |
| 1162 | |
| 1163 | /* |
| 1164 | * We can walk the hash lockfree, because the hash only |
| 1165 | * grows, and we are careful when adding entries to the end: |
| 1166 | */ |
| 1167 | list_for_each_entry(class, hash_head, hash_entry) |
| 1168 | if (class->key == key) |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1169 | return class; |
| 1170 | |
| 1171 | return NULL; |
| 1172 | } |
| 1173 | |
| 1174 | /* |
| 1175 | * Register a lock's class in the hash-table, if the class is not present |
| 1176 | * yet. Otherwise we look it up. We cache the result in the lock object |
| 1177 | * itself, so actual lookup of the hash should be once per lock object. |
| 1178 | */ |
| 1179 | static inline struct lock_class * |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 1180 | register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force) |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1181 | { |
| 1182 | struct lockdep_subclass_key *key; |
| 1183 | struct list_head *hash_head; |
| 1184 | struct lock_class *class; |
| 1185 | |
| 1186 | class = look_up_lock_class(lock, subclass); |
| 1187 | if (likely(class)) |
| 1188 | return class; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1189 | |
| 1190 | /* |
| 1191 | * Debug-check: all keys must be persistent! |
| 1192 | */ |
| 1193 | if (!static_obj(lock->key)) { |
| 1194 | debug_locks_off(); |
| 1195 | printk("INFO: trying to register non-static key.\n"); |
| 1196 | printk("the code is fine but needs lockdep annotation.\n"); |
| 1197 | printk("turning off the locking correctness validator.\n"); |
| 1198 | dump_stack(); |
| 1199 | |
| 1200 | return NULL; |
| 1201 | } |
| 1202 | |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1203 | key = lock->key->subkeys + subclass; |
| 1204 | hash_head = classhashentry(key); |
| 1205 | |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1206 | __raw_spin_lock(&hash_lock); |
| 1207 | /* |
| 1208 | * We have to do the hash-walk again, to avoid races |
| 1209 | * with another CPU: |
| 1210 | */ |
| 1211 | list_for_each_entry(class, hash_head, hash_entry) |
| 1212 | if (class->key == key) |
| 1213 | goto out_unlock_set; |
| 1214 | /* |
| 1215 | * Allocate a new key from the static array, and add it to |
| 1216 | * the hash: |
| 1217 | */ |
| 1218 | if (nr_lock_classes >= MAX_LOCKDEP_KEYS) { |
| 1219 | __raw_spin_unlock(&hash_lock); |
| 1220 | debug_locks_off(); |
| 1221 | printk("BUG: MAX_LOCKDEP_KEYS too low!\n"); |
| 1222 | printk("turning off the locking correctness validator.\n"); |
| 1223 | return NULL; |
| 1224 | } |
| 1225 | class = lock_classes + nr_lock_classes++; |
| 1226 | debug_atomic_inc(&nr_unused_locks); |
| 1227 | class->key = key; |
| 1228 | class->name = lock->name; |
| 1229 | class->subclass = subclass; |
| 1230 | INIT_LIST_HEAD(&class->lock_entry); |
| 1231 | INIT_LIST_HEAD(&class->locks_before); |
| 1232 | INIT_LIST_HEAD(&class->locks_after); |
| 1233 | class->name_version = count_matching_names(class); |
| 1234 | /* |
| 1235 | * We use RCU's safe list-add method to make |
| 1236 | * parallel walking of the hash-list safe: |
| 1237 | */ |
| 1238 | list_add_tail_rcu(&class->hash_entry, hash_head); |
| 1239 | |
| 1240 | if (verbose(class)) { |
| 1241 | __raw_spin_unlock(&hash_lock); |
| 1242 | printk("\nnew class %p: %s", class->key, class->name); |
| 1243 | if (class->name_version > 1) |
| 1244 | printk("#%d", class->name_version); |
| 1245 | printk("\n"); |
| 1246 | dump_stack(); |
| 1247 | __raw_spin_lock(&hash_lock); |
| 1248 | } |
| 1249 | out_unlock_set: |
| 1250 | __raw_spin_unlock(&hash_lock); |
| 1251 | |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 1252 | if (!subclass || force) |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1253 | lock->class_cache = class; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1254 | |
| 1255 | DEBUG_LOCKS_WARN_ON(class->subclass != subclass); |
| 1256 | |
| 1257 | return class; |
| 1258 | } |
| 1259 | |
| 1260 | /* |
| 1261 | * Look up a dependency chain. If the key is not present yet then |
| 1262 | * add it and return 0 - in this case the new dependency chain is |
| 1263 | * validated. If the key is already hashed, return 1. |
| 1264 | */ |
| 1265 | static inline int lookup_chain_cache(u64 chain_key) |
| 1266 | { |
| 1267 | struct list_head *hash_head = chainhashentry(chain_key); |
| 1268 | struct lock_chain *chain; |
| 1269 | |
| 1270 | DEBUG_LOCKS_WARN_ON(!irqs_disabled()); |
| 1271 | /* |
| 1272 | * We can walk it lock-free, because entries only get added |
| 1273 | * to the hash: |
| 1274 | */ |
| 1275 | list_for_each_entry(chain, hash_head, entry) { |
| 1276 | if (chain->chain_key == chain_key) { |
| 1277 | cache_hit: |
| 1278 | debug_atomic_inc(&chain_lookup_hits); |
| 1279 | /* |
| 1280 | * In the debugging case, force redundant checking |
| 1281 | * by returning 1: |
| 1282 | */ |
| 1283 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 1284 | __raw_spin_lock(&hash_lock); |
| 1285 | return 1; |
| 1286 | #endif |
| 1287 | return 0; |
| 1288 | } |
| 1289 | } |
| 1290 | /* |
| 1291 | * Allocate a new chain entry from the static array, and add |
| 1292 | * it to the hash: |
| 1293 | */ |
| 1294 | __raw_spin_lock(&hash_lock); |
| 1295 | /* |
| 1296 | * We have to walk the chain again locked - to avoid duplicates: |
| 1297 | */ |
| 1298 | list_for_each_entry(chain, hash_head, entry) { |
| 1299 | if (chain->chain_key == chain_key) { |
| 1300 | __raw_spin_unlock(&hash_lock); |
| 1301 | goto cache_hit; |
| 1302 | } |
| 1303 | } |
| 1304 | if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) { |
| 1305 | __raw_spin_unlock(&hash_lock); |
| 1306 | debug_locks_off(); |
| 1307 | printk("BUG: MAX_LOCKDEP_CHAINS too low!\n"); |
| 1308 | printk("turning off the locking correctness validator.\n"); |
| 1309 | return 0; |
| 1310 | } |
| 1311 | chain = lock_chains + nr_lock_chains++; |
| 1312 | chain->chain_key = chain_key; |
| 1313 | list_add_tail_rcu(&chain->entry, hash_head); |
| 1314 | debug_atomic_inc(&chain_lookup_misses); |
| 1315 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 1316 | if (current->hardirq_context) |
| 1317 | nr_hardirq_chains++; |
| 1318 | else { |
| 1319 | if (current->softirq_context) |
| 1320 | nr_softirq_chains++; |
| 1321 | else |
| 1322 | nr_process_chains++; |
| 1323 | } |
| 1324 | #else |
| 1325 | nr_process_chains++; |
| 1326 | #endif |
| 1327 | |
| 1328 | return 1; |
| 1329 | } |
| 1330 | |
| 1331 | /* |
| 1332 | * We are building curr_chain_key incrementally, so double-check |
| 1333 | * it from scratch, to make sure that it's done correctly: |
| 1334 | */ |
| 1335 | static void check_chain_key(struct task_struct *curr) |
| 1336 | { |
| 1337 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 1338 | struct held_lock *hlock, *prev_hlock = NULL; |
| 1339 | unsigned int i, id; |
| 1340 | u64 chain_key = 0; |
| 1341 | |
| 1342 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 1343 | hlock = curr->held_locks + i; |
| 1344 | if (chain_key != hlock->prev_chain_key) { |
| 1345 | debug_locks_off(); |
| 1346 | printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n", |
| 1347 | curr->lockdep_depth, i, |
| 1348 | (unsigned long long)chain_key, |
| 1349 | (unsigned long long)hlock->prev_chain_key); |
| 1350 | WARN_ON(1); |
| 1351 | return; |
| 1352 | } |
| 1353 | id = hlock->class - lock_classes; |
| 1354 | DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS); |
| 1355 | if (prev_hlock && (prev_hlock->irq_context != |
| 1356 | hlock->irq_context)) |
| 1357 | chain_key = 0; |
| 1358 | chain_key = iterate_chain_key(chain_key, id); |
| 1359 | prev_hlock = hlock; |
| 1360 | } |
| 1361 | if (chain_key != curr->curr_chain_key) { |
| 1362 | debug_locks_off(); |
| 1363 | printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n", |
| 1364 | curr->lockdep_depth, i, |
| 1365 | (unsigned long long)chain_key, |
| 1366 | (unsigned long long)curr->curr_chain_key); |
| 1367 | WARN_ON(1); |
| 1368 | } |
| 1369 | #endif |
| 1370 | } |
| 1371 | |
| 1372 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 1373 | |
| 1374 | /* |
| 1375 | * print irq inversion bug: |
| 1376 | */ |
| 1377 | static int |
| 1378 | print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, |
| 1379 | struct held_lock *this, int forwards, |
| 1380 | const char *irqclass) |
| 1381 | { |
| 1382 | __raw_spin_unlock(&hash_lock); |
| 1383 | debug_locks_off(); |
| 1384 | if (debug_locks_silent) |
| 1385 | return 0; |
| 1386 | |
| 1387 | printk("\n=========================================================\n"); |
| 1388 | printk( "[ INFO: possible irq lock inversion dependency detected ]\n"); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 1389 | print_kernel_version(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1390 | printk( "---------------------------------------------------------\n"); |
| 1391 | printk("%s/%d just changed the state of lock:\n", |
| 1392 | curr->comm, curr->pid); |
| 1393 | print_lock(this); |
| 1394 | if (forwards) |
| 1395 | printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass); |
| 1396 | else |
| 1397 | printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass); |
| 1398 | print_lock_name(other); |
| 1399 | printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); |
| 1400 | |
| 1401 | printk("\nother info that might help us debug this:\n"); |
| 1402 | lockdep_print_held_locks(curr); |
| 1403 | |
| 1404 | printk("\nthe first lock's dependencies:\n"); |
| 1405 | print_lock_dependencies(this->class, 0); |
| 1406 | |
| 1407 | printk("\nthe second lock's dependencies:\n"); |
| 1408 | print_lock_dependencies(other, 0); |
| 1409 | |
| 1410 | printk("\nstack backtrace:\n"); |
| 1411 | dump_stack(); |
| 1412 | |
| 1413 | return 0; |
| 1414 | } |
| 1415 | |
| 1416 | /* |
| 1417 | * Prove that in the forwards-direction subgraph starting at <this> |
| 1418 | * there is no lock matching <mask>: |
| 1419 | */ |
| 1420 | static int |
| 1421 | check_usage_forwards(struct task_struct *curr, struct held_lock *this, |
| 1422 | enum lock_usage_bit bit, const char *irqclass) |
| 1423 | { |
| 1424 | int ret; |
| 1425 | |
| 1426 | find_usage_bit = bit; |
| 1427 | /* fills in <forwards_match> */ |
| 1428 | ret = find_usage_forwards(this->class, 0); |
| 1429 | if (!ret || ret == 1) |
| 1430 | return ret; |
| 1431 | |
| 1432 | return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass); |
| 1433 | } |
| 1434 | |
| 1435 | /* |
| 1436 | * Prove that in the backwards-direction subgraph starting at <this> |
| 1437 | * there is no lock matching <mask>: |
| 1438 | */ |
| 1439 | static int |
| 1440 | check_usage_backwards(struct task_struct *curr, struct held_lock *this, |
| 1441 | enum lock_usage_bit bit, const char *irqclass) |
| 1442 | { |
| 1443 | int ret; |
| 1444 | |
| 1445 | find_usage_bit = bit; |
| 1446 | /* fills in <backwards_match> */ |
| 1447 | ret = find_usage_backwards(this->class, 0); |
| 1448 | if (!ret || ret == 1) |
| 1449 | return ret; |
| 1450 | |
| 1451 | return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass); |
| 1452 | } |
| 1453 | |
| 1454 | static inline void print_irqtrace_events(struct task_struct *curr) |
| 1455 | { |
| 1456 | printk("irq event stamp: %u\n", curr->irq_events); |
| 1457 | printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event); |
| 1458 | print_ip_sym(curr->hardirq_enable_ip); |
| 1459 | printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event); |
| 1460 | print_ip_sym(curr->hardirq_disable_ip); |
| 1461 | printk("softirqs last enabled at (%u): ", curr->softirq_enable_event); |
| 1462 | print_ip_sym(curr->softirq_enable_ip); |
| 1463 | printk("softirqs last disabled at (%u): ", curr->softirq_disable_event); |
| 1464 | print_ip_sym(curr->softirq_disable_ip); |
| 1465 | } |
| 1466 | |
| 1467 | #else |
| 1468 | static inline void print_irqtrace_events(struct task_struct *curr) |
| 1469 | { |
| 1470 | } |
| 1471 | #endif |
| 1472 | |
| 1473 | static int |
| 1474 | print_usage_bug(struct task_struct *curr, struct held_lock *this, |
| 1475 | enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit) |
| 1476 | { |
| 1477 | __raw_spin_unlock(&hash_lock); |
| 1478 | debug_locks_off(); |
| 1479 | if (debug_locks_silent) |
| 1480 | return 0; |
| 1481 | |
| 1482 | printk("\n=================================\n"); |
| 1483 | printk( "[ INFO: inconsistent lock state ]\n"); |
Dave Jones | 99de055 | 2006-09-29 02:00:10 -0700 | [diff] [blame] | 1484 | print_kernel_version(); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1485 | printk( "---------------------------------\n"); |
| 1486 | |
| 1487 | printk("inconsistent {%s} -> {%s} usage.\n", |
| 1488 | usage_str[prev_bit], usage_str[new_bit]); |
| 1489 | |
| 1490 | printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n", |
| 1491 | curr->comm, curr->pid, |
| 1492 | trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT, |
| 1493 | trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT, |
| 1494 | trace_hardirqs_enabled(curr), |
| 1495 | trace_softirqs_enabled(curr)); |
| 1496 | print_lock(this); |
| 1497 | |
| 1498 | printk("{%s} state was registered at:\n", usage_str[prev_bit]); |
| 1499 | print_stack_trace(this->class->usage_traces + prev_bit, 1); |
| 1500 | |
| 1501 | print_irqtrace_events(curr); |
| 1502 | printk("\nother info that might help us debug this:\n"); |
| 1503 | lockdep_print_held_locks(curr); |
| 1504 | |
| 1505 | printk("\nstack backtrace:\n"); |
| 1506 | dump_stack(); |
| 1507 | |
| 1508 | return 0; |
| 1509 | } |
| 1510 | |
| 1511 | /* |
| 1512 | * Print out an error if an invalid bit is set: |
| 1513 | */ |
| 1514 | static inline int |
| 1515 | valid_state(struct task_struct *curr, struct held_lock *this, |
| 1516 | enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit) |
| 1517 | { |
| 1518 | if (unlikely(this->class->usage_mask & (1 << bad_bit))) |
| 1519 | return print_usage_bug(curr, this, bad_bit, new_bit); |
| 1520 | return 1; |
| 1521 | } |
| 1522 | |
| 1523 | #define STRICT_READ_CHECKS 1 |
| 1524 | |
| 1525 | /* |
| 1526 | * Mark a lock with a usage bit, and validate the state transition: |
| 1527 | */ |
| 1528 | static int mark_lock(struct task_struct *curr, struct held_lock *this, |
| 1529 | enum lock_usage_bit new_bit, unsigned long ip) |
| 1530 | { |
| 1531 | unsigned int new_mask = 1 << new_bit, ret = 1; |
| 1532 | |
| 1533 | /* |
| 1534 | * If already set then do not dirty the cacheline, |
| 1535 | * nor do any checks: |
| 1536 | */ |
| 1537 | if (likely(this->class->usage_mask & new_mask)) |
| 1538 | return 1; |
| 1539 | |
| 1540 | __raw_spin_lock(&hash_lock); |
| 1541 | /* |
| 1542 | * Make sure we didnt race: |
| 1543 | */ |
| 1544 | if (unlikely(this->class->usage_mask & new_mask)) { |
| 1545 | __raw_spin_unlock(&hash_lock); |
| 1546 | return 1; |
| 1547 | } |
| 1548 | |
| 1549 | this->class->usage_mask |= new_mask; |
| 1550 | |
| 1551 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 1552 | if (new_bit == LOCK_ENABLED_HARDIRQS || |
| 1553 | new_bit == LOCK_ENABLED_HARDIRQS_READ) |
| 1554 | ip = curr->hardirq_enable_ip; |
| 1555 | else if (new_bit == LOCK_ENABLED_SOFTIRQS || |
| 1556 | new_bit == LOCK_ENABLED_SOFTIRQS_READ) |
| 1557 | ip = curr->softirq_enable_ip; |
| 1558 | #endif |
| 1559 | if (!save_trace(this->class->usage_traces + new_bit)) |
| 1560 | return 0; |
| 1561 | |
| 1562 | switch (new_bit) { |
| 1563 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 1564 | case LOCK_USED_IN_HARDIRQ: |
| 1565 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) |
| 1566 | return 0; |
| 1567 | if (!valid_state(curr, this, new_bit, |
| 1568 | LOCK_ENABLED_HARDIRQS_READ)) |
| 1569 | return 0; |
| 1570 | /* |
| 1571 | * just marked it hardirq-safe, check that this lock |
| 1572 | * took no hardirq-unsafe lock in the past: |
| 1573 | */ |
| 1574 | if (!check_usage_forwards(curr, this, |
| 1575 | LOCK_ENABLED_HARDIRQS, "hard")) |
| 1576 | return 0; |
| 1577 | #if STRICT_READ_CHECKS |
| 1578 | /* |
| 1579 | * just marked it hardirq-safe, check that this lock |
| 1580 | * took no hardirq-unsafe-read lock in the past: |
| 1581 | */ |
| 1582 | if (!check_usage_forwards(curr, this, |
| 1583 | LOCK_ENABLED_HARDIRQS_READ, "hard-read")) |
| 1584 | return 0; |
| 1585 | #endif |
| 1586 | if (hardirq_verbose(this->class)) |
| 1587 | ret = 2; |
| 1588 | break; |
| 1589 | case LOCK_USED_IN_SOFTIRQ: |
| 1590 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) |
| 1591 | return 0; |
| 1592 | if (!valid_state(curr, this, new_bit, |
| 1593 | LOCK_ENABLED_SOFTIRQS_READ)) |
| 1594 | return 0; |
| 1595 | /* |
| 1596 | * just marked it softirq-safe, check that this lock |
| 1597 | * took no softirq-unsafe lock in the past: |
| 1598 | */ |
| 1599 | if (!check_usage_forwards(curr, this, |
| 1600 | LOCK_ENABLED_SOFTIRQS, "soft")) |
| 1601 | return 0; |
| 1602 | #if STRICT_READ_CHECKS |
| 1603 | /* |
| 1604 | * just marked it softirq-safe, check that this lock |
| 1605 | * took no softirq-unsafe-read lock in the past: |
| 1606 | */ |
| 1607 | if (!check_usage_forwards(curr, this, |
| 1608 | LOCK_ENABLED_SOFTIRQS_READ, "soft-read")) |
| 1609 | return 0; |
| 1610 | #endif |
| 1611 | if (softirq_verbose(this->class)) |
| 1612 | ret = 2; |
| 1613 | break; |
| 1614 | case LOCK_USED_IN_HARDIRQ_READ: |
| 1615 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS)) |
| 1616 | return 0; |
| 1617 | /* |
| 1618 | * just marked it hardirq-read-safe, check that this lock |
| 1619 | * took no hardirq-unsafe lock in the past: |
| 1620 | */ |
| 1621 | if (!check_usage_forwards(curr, this, |
| 1622 | LOCK_ENABLED_HARDIRQS, "hard")) |
| 1623 | return 0; |
| 1624 | if (hardirq_verbose(this->class)) |
| 1625 | ret = 2; |
| 1626 | break; |
| 1627 | case LOCK_USED_IN_SOFTIRQ_READ: |
| 1628 | if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS)) |
| 1629 | return 0; |
| 1630 | /* |
| 1631 | * just marked it softirq-read-safe, check that this lock |
| 1632 | * took no softirq-unsafe lock in the past: |
| 1633 | */ |
| 1634 | if (!check_usage_forwards(curr, this, |
| 1635 | LOCK_ENABLED_SOFTIRQS, "soft")) |
| 1636 | return 0; |
| 1637 | if (softirq_verbose(this->class)) |
| 1638 | ret = 2; |
| 1639 | break; |
| 1640 | case LOCK_ENABLED_HARDIRQS: |
| 1641 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) |
| 1642 | return 0; |
| 1643 | if (!valid_state(curr, this, new_bit, |
| 1644 | LOCK_USED_IN_HARDIRQ_READ)) |
| 1645 | return 0; |
| 1646 | /* |
| 1647 | * just marked it hardirq-unsafe, check that no hardirq-safe |
| 1648 | * lock in the system ever took it in the past: |
| 1649 | */ |
| 1650 | if (!check_usage_backwards(curr, this, |
| 1651 | LOCK_USED_IN_HARDIRQ, "hard")) |
| 1652 | return 0; |
| 1653 | #if STRICT_READ_CHECKS |
| 1654 | /* |
| 1655 | * just marked it hardirq-unsafe, check that no |
| 1656 | * hardirq-safe-read lock in the system ever took |
| 1657 | * it in the past: |
| 1658 | */ |
| 1659 | if (!check_usage_backwards(curr, this, |
| 1660 | LOCK_USED_IN_HARDIRQ_READ, "hard-read")) |
| 1661 | return 0; |
| 1662 | #endif |
| 1663 | if (hardirq_verbose(this->class)) |
| 1664 | ret = 2; |
| 1665 | break; |
| 1666 | case LOCK_ENABLED_SOFTIRQS: |
| 1667 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) |
| 1668 | return 0; |
| 1669 | if (!valid_state(curr, this, new_bit, |
| 1670 | LOCK_USED_IN_SOFTIRQ_READ)) |
| 1671 | return 0; |
| 1672 | /* |
| 1673 | * just marked it softirq-unsafe, check that no softirq-safe |
| 1674 | * lock in the system ever took it in the past: |
| 1675 | */ |
| 1676 | if (!check_usage_backwards(curr, this, |
| 1677 | LOCK_USED_IN_SOFTIRQ, "soft")) |
| 1678 | return 0; |
| 1679 | #if STRICT_READ_CHECKS |
| 1680 | /* |
| 1681 | * just marked it softirq-unsafe, check that no |
| 1682 | * softirq-safe-read lock in the system ever took |
| 1683 | * it in the past: |
| 1684 | */ |
| 1685 | if (!check_usage_backwards(curr, this, |
| 1686 | LOCK_USED_IN_SOFTIRQ_READ, "soft-read")) |
| 1687 | return 0; |
| 1688 | #endif |
| 1689 | if (softirq_verbose(this->class)) |
| 1690 | ret = 2; |
| 1691 | break; |
| 1692 | case LOCK_ENABLED_HARDIRQS_READ: |
| 1693 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ)) |
| 1694 | return 0; |
| 1695 | #if STRICT_READ_CHECKS |
| 1696 | /* |
| 1697 | * just marked it hardirq-read-unsafe, check that no |
| 1698 | * hardirq-safe lock in the system ever took it in the past: |
| 1699 | */ |
| 1700 | if (!check_usage_backwards(curr, this, |
| 1701 | LOCK_USED_IN_HARDIRQ, "hard")) |
| 1702 | return 0; |
| 1703 | #endif |
| 1704 | if (hardirq_verbose(this->class)) |
| 1705 | ret = 2; |
| 1706 | break; |
| 1707 | case LOCK_ENABLED_SOFTIRQS_READ: |
| 1708 | if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ)) |
| 1709 | return 0; |
| 1710 | #if STRICT_READ_CHECKS |
| 1711 | /* |
| 1712 | * just marked it softirq-read-unsafe, check that no |
| 1713 | * softirq-safe lock in the system ever took it in the past: |
| 1714 | */ |
| 1715 | if (!check_usage_backwards(curr, this, |
| 1716 | LOCK_USED_IN_SOFTIRQ, "soft")) |
| 1717 | return 0; |
| 1718 | #endif |
| 1719 | if (softirq_verbose(this->class)) |
| 1720 | ret = 2; |
| 1721 | break; |
| 1722 | #endif |
| 1723 | case LOCK_USED: |
| 1724 | /* |
| 1725 | * Add it to the global list of classes: |
| 1726 | */ |
| 1727 | list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes); |
| 1728 | debug_atomic_dec(&nr_unused_locks); |
| 1729 | break; |
| 1730 | default: |
| 1731 | debug_locks_off(); |
| 1732 | WARN_ON(1); |
| 1733 | return 0; |
| 1734 | } |
| 1735 | |
| 1736 | __raw_spin_unlock(&hash_lock); |
| 1737 | |
| 1738 | /* |
| 1739 | * We must printk outside of the hash_lock: |
| 1740 | */ |
| 1741 | if (ret == 2) { |
| 1742 | printk("\nmarked lock as {%s}:\n", usage_str[new_bit]); |
| 1743 | print_lock(this); |
| 1744 | print_irqtrace_events(curr); |
| 1745 | dump_stack(); |
| 1746 | } |
| 1747 | |
| 1748 | return ret; |
| 1749 | } |
| 1750 | |
| 1751 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 1752 | /* |
| 1753 | * Mark all held locks with a usage bit: |
| 1754 | */ |
| 1755 | static int |
| 1756 | mark_held_locks(struct task_struct *curr, int hardirq, unsigned long ip) |
| 1757 | { |
| 1758 | enum lock_usage_bit usage_bit; |
| 1759 | struct held_lock *hlock; |
| 1760 | int i; |
| 1761 | |
| 1762 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 1763 | hlock = curr->held_locks + i; |
| 1764 | |
| 1765 | if (hardirq) { |
| 1766 | if (hlock->read) |
| 1767 | usage_bit = LOCK_ENABLED_HARDIRQS_READ; |
| 1768 | else |
| 1769 | usage_bit = LOCK_ENABLED_HARDIRQS; |
| 1770 | } else { |
| 1771 | if (hlock->read) |
| 1772 | usage_bit = LOCK_ENABLED_SOFTIRQS_READ; |
| 1773 | else |
| 1774 | usage_bit = LOCK_ENABLED_SOFTIRQS; |
| 1775 | } |
| 1776 | if (!mark_lock(curr, hlock, usage_bit, ip)) |
| 1777 | return 0; |
| 1778 | } |
| 1779 | |
| 1780 | return 1; |
| 1781 | } |
| 1782 | |
| 1783 | /* |
| 1784 | * Debugging helper: via this flag we know that we are in |
| 1785 | * 'early bootup code', and will warn about any invalid irqs-on event: |
| 1786 | */ |
| 1787 | static int early_boot_irqs_enabled; |
| 1788 | |
| 1789 | void early_boot_irqs_off(void) |
| 1790 | { |
| 1791 | early_boot_irqs_enabled = 0; |
| 1792 | } |
| 1793 | |
| 1794 | void early_boot_irqs_on(void) |
| 1795 | { |
| 1796 | early_boot_irqs_enabled = 1; |
| 1797 | } |
| 1798 | |
| 1799 | /* |
| 1800 | * Hardirqs will be enabled: |
| 1801 | */ |
| 1802 | void trace_hardirqs_on(void) |
| 1803 | { |
| 1804 | struct task_struct *curr = current; |
| 1805 | unsigned long ip; |
| 1806 | |
| 1807 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
| 1808 | return; |
| 1809 | |
| 1810 | if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled))) |
| 1811 | return; |
| 1812 | |
| 1813 | if (unlikely(curr->hardirqs_enabled)) { |
| 1814 | debug_atomic_inc(&redundant_hardirqs_on); |
| 1815 | return; |
| 1816 | } |
| 1817 | /* we'll do an OFF -> ON transition: */ |
| 1818 | curr->hardirqs_enabled = 1; |
| 1819 | ip = (unsigned long) __builtin_return_address(0); |
| 1820 | |
| 1821 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 1822 | return; |
| 1823 | if (DEBUG_LOCKS_WARN_ON(current->hardirq_context)) |
| 1824 | return; |
| 1825 | /* |
| 1826 | * We are going to turn hardirqs on, so set the |
| 1827 | * usage bit for all held locks: |
| 1828 | */ |
| 1829 | if (!mark_held_locks(curr, 1, ip)) |
| 1830 | return; |
| 1831 | /* |
| 1832 | * If we have softirqs enabled, then set the usage |
| 1833 | * bit for all held locks. (disabled hardirqs prevented |
| 1834 | * this bit from being set before) |
| 1835 | */ |
| 1836 | if (curr->softirqs_enabled) |
| 1837 | if (!mark_held_locks(curr, 0, ip)) |
| 1838 | return; |
| 1839 | |
| 1840 | curr->hardirq_enable_ip = ip; |
| 1841 | curr->hardirq_enable_event = ++curr->irq_events; |
| 1842 | debug_atomic_inc(&hardirqs_on_events); |
| 1843 | } |
| 1844 | |
| 1845 | EXPORT_SYMBOL(trace_hardirqs_on); |
| 1846 | |
| 1847 | /* |
| 1848 | * Hardirqs were disabled: |
| 1849 | */ |
| 1850 | void trace_hardirqs_off(void) |
| 1851 | { |
| 1852 | struct task_struct *curr = current; |
| 1853 | |
| 1854 | if (unlikely(!debug_locks || current->lockdep_recursion)) |
| 1855 | return; |
| 1856 | |
| 1857 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 1858 | return; |
| 1859 | |
| 1860 | if (curr->hardirqs_enabled) { |
| 1861 | /* |
| 1862 | * We have done an ON -> OFF transition: |
| 1863 | */ |
| 1864 | curr->hardirqs_enabled = 0; |
| 1865 | curr->hardirq_disable_ip = _RET_IP_; |
| 1866 | curr->hardirq_disable_event = ++curr->irq_events; |
| 1867 | debug_atomic_inc(&hardirqs_off_events); |
| 1868 | } else |
| 1869 | debug_atomic_inc(&redundant_hardirqs_off); |
| 1870 | } |
| 1871 | |
| 1872 | EXPORT_SYMBOL(trace_hardirqs_off); |
| 1873 | |
| 1874 | /* |
| 1875 | * Softirqs will be enabled: |
| 1876 | */ |
| 1877 | void trace_softirqs_on(unsigned long ip) |
| 1878 | { |
| 1879 | struct task_struct *curr = current; |
| 1880 | |
| 1881 | if (unlikely(!debug_locks)) |
| 1882 | return; |
| 1883 | |
| 1884 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 1885 | return; |
| 1886 | |
| 1887 | if (curr->softirqs_enabled) { |
| 1888 | debug_atomic_inc(&redundant_softirqs_on); |
| 1889 | return; |
| 1890 | } |
| 1891 | |
| 1892 | /* |
| 1893 | * We'll do an OFF -> ON transition: |
| 1894 | */ |
| 1895 | curr->softirqs_enabled = 1; |
| 1896 | curr->softirq_enable_ip = ip; |
| 1897 | curr->softirq_enable_event = ++curr->irq_events; |
| 1898 | debug_atomic_inc(&softirqs_on_events); |
| 1899 | /* |
| 1900 | * We are going to turn softirqs on, so set the |
| 1901 | * usage bit for all held locks, if hardirqs are |
| 1902 | * enabled too: |
| 1903 | */ |
| 1904 | if (curr->hardirqs_enabled) |
| 1905 | mark_held_locks(curr, 0, ip); |
| 1906 | } |
| 1907 | |
| 1908 | /* |
| 1909 | * Softirqs were disabled: |
| 1910 | */ |
| 1911 | void trace_softirqs_off(unsigned long ip) |
| 1912 | { |
| 1913 | struct task_struct *curr = current; |
| 1914 | |
| 1915 | if (unlikely(!debug_locks)) |
| 1916 | return; |
| 1917 | |
| 1918 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 1919 | return; |
| 1920 | |
| 1921 | if (curr->softirqs_enabled) { |
| 1922 | /* |
| 1923 | * We have done an ON -> OFF transition: |
| 1924 | */ |
| 1925 | curr->softirqs_enabled = 0; |
| 1926 | curr->softirq_disable_ip = ip; |
| 1927 | curr->softirq_disable_event = ++curr->irq_events; |
| 1928 | debug_atomic_inc(&softirqs_off_events); |
| 1929 | DEBUG_LOCKS_WARN_ON(!softirq_count()); |
| 1930 | } else |
| 1931 | debug_atomic_inc(&redundant_softirqs_off); |
| 1932 | } |
| 1933 | |
| 1934 | #endif |
| 1935 | |
| 1936 | /* |
| 1937 | * Initialize a lock instance's lock-class mapping info: |
| 1938 | */ |
| 1939 | void lockdep_init_map(struct lockdep_map *lock, const char *name, |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 1940 | struct lock_class_key *key, int subclass) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1941 | { |
| 1942 | if (unlikely(!debug_locks)) |
| 1943 | return; |
| 1944 | |
| 1945 | if (DEBUG_LOCKS_WARN_ON(!key)) |
| 1946 | return; |
| 1947 | if (DEBUG_LOCKS_WARN_ON(!name)) |
| 1948 | return; |
| 1949 | /* |
| 1950 | * Sanity check, the lock-class key must be persistent: |
| 1951 | */ |
| 1952 | if (!static_obj(key)) { |
| 1953 | printk("BUG: key %p not in .data!\n", key); |
| 1954 | DEBUG_LOCKS_WARN_ON(1); |
| 1955 | return; |
| 1956 | } |
| 1957 | lock->name = name; |
| 1958 | lock->key = key; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1959 | lock->class_cache = NULL; |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 1960 | if (subclass) |
| 1961 | register_lock_class(lock, subclass, 1); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1962 | } |
| 1963 | |
| 1964 | EXPORT_SYMBOL_GPL(lockdep_init_map); |
| 1965 | |
| 1966 | /* |
| 1967 | * This gets called for every mutex_lock*()/spin_lock*() operation. |
| 1968 | * We maintain the dependency maps and validate the locking attempt: |
| 1969 | */ |
| 1970 | static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
| 1971 | int trylock, int read, int check, int hardirqs_off, |
| 1972 | unsigned long ip) |
| 1973 | { |
| 1974 | struct task_struct *curr = current; |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1975 | struct lock_class *class = NULL; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1976 | struct held_lock *hlock; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1977 | unsigned int depth, id; |
| 1978 | int chain_head = 0; |
| 1979 | u64 chain_key; |
| 1980 | |
| 1981 | if (unlikely(!debug_locks)) |
| 1982 | return 0; |
| 1983 | |
| 1984 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 1985 | return 0; |
| 1986 | |
| 1987 | if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) { |
| 1988 | debug_locks_off(); |
| 1989 | printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n"); |
| 1990 | printk("turning off the locking correctness validator.\n"); |
| 1991 | return 0; |
| 1992 | } |
| 1993 | |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 1994 | if (!subclass) |
| 1995 | class = lock->class_cache; |
| 1996 | /* |
| 1997 | * Not cached yet or subclass? |
| 1998 | */ |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 1999 | if (unlikely(!class)) { |
Peter Zijlstra | 4dfbb9d | 2006-10-11 01:45:14 -0400 | [diff] [blame] | 2000 | class = register_lock_class(lock, subclass, 0); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2001 | if (!class) |
| 2002 | return 0; |
| 2003 | } |
| 2004 | debug_atomic_inc((atomic_t *)&class->ops); |
| 2005 | if (very_verbose(class)) { |
| 2006 | printk("\nacquire class [%p] %s", class->key, class->name); |
| 2007 | if (class->name_version > 1) |
| 2008 | printk("#%d", class->name_version); |
| 2009 | printk("\n"); |
| 2010 | dump_stack(); |
| 2011 | } |
| 2012 | |
| 2013 | /* |
| 2014 | * Add the lock to the list of currently held locks. |
| 2015 | * (we dont increase the depth just yet, up until the |
| 2016 | * dependency checks are done) |
| 2017 | */ |
| 2018 | depth = curr->lockdep_depth; |
| 2019 | if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH)) |
| 2020 | return 0; |
| 2021 | |
| 2022 | hlock = curr->held_locks + depth; |
| 2023 | |
| 2024 | hlock->class = class; |
| 2025 | hlock->acquire_ip = ip; |
| 2026 | hlock->instance = lock; |
| 2027 | hlock->trylock = trylock; |
| 2028 | hlock->read = read; |
| 2029 | hlock->check = check; |
| 2030 | hlock->hardirqs_off = hardirqs_off; |
| 2031 | |
| 2032 | if (check != 2) |
| 2033 | goto out_calc_hash; |
| 2034 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 2035 | /* |
| 2036 | * If non-trylock use in a hardirq or softirq context, then |
| 2037 | * mark the lock as used in these contexts: |
| 2038 | */ |
| 2039 | if (!trylock) { |
| 2040 | if (read) { |
| 2041 | if (curr->hardirq_context) |
| 2042 | if (!mark_lock(curr, hlock, |
| 2043 | LOCK_USED_IN_HARDIRQ_READ, ip)) |
| 2044 | return 0; |
| 2045 | if (curr->softirq_context) |
| 2046 | if (!mark_lock(curr, hlock, |
| 2047 | LOCK_USED_IN_SOFTIRQ_READ, ip)) |
| 2048 | return 0; |
| 2049 | } else { |
| 2050 | if (curr->hardirq_context) |
| 2051 | if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ, ip)) |
| 2052 | return 0; |
| 2053 | if (curr->softirq_context) |
| 2054 | if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ, ip)) |
| 2055 | return 0; |
| 2056 | } |
| 2057 | } |
| 2058 | if (!hardirqs_off) { |
| 2059 | if (read) { |
| 2060 | if (!mark_lock(curr, hlock, |
| 2061 | LOCK_ENABLED_HARDIRQS_READ, ip)) |
| 2062 | return 0; |
| 2063 | if (curr->softirqs_enabled) |
| 2064 | if (!mark_lock(curr, hlock, |
| 2065 | LOCK_ENABLED_SOFTIRQS_READ, ip)) |
| 2066 | return 0; |
| 2067 | } else { |
| 2068 | if (!mark_lock(curr, hlock, |
| 2069 | LOCK_ENABLED_HARDIRQS, ip)) |
| 2070 | return 0; |
| 2071 | if (curr->softirqs_enabled) |
| 2072 | if (!mark_lock(curr, hlock, |
| 2073 | LOCK_ENABLED_SOFTIRQS, ip)) |
| 2074 | return 0; |
| 2075 | } |
| 2076 | } |
| 2077 | #endif |
| 2078 | /* mark it as used: */ |
| 2079 | if (!mark_lock(curr, hlock, LOCK_USED, ip)) |
| 2080 | return 0; |
| 2081 | out_calc_hash: |
| 2082 | /* |
| 2083 | * Calculate the chain hash: it's the combined has of all the |
| 2084 | * lock keys along the dependency chain. We save the hash value |
| 2085 | * at every step so that we can get the current hash easily |
| 2086 | * after unlock. The chain hash is then used to cache dependency |
| 2087 | * results. |
| 2088 | * |
| 2089 | * The 'key ID' is what is the most compact key value to drive |
| 2090 | * the hash, not class->key. |
| 2091 | */ |
| 2092 | id = class - lock_classes; |
| 2093 | if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS)) |
| 2094 | return 0; |
| 2095 | |
| 2096 | chain_key = curr->curr_chain_key; |
| 2097 | if (!depth) { |
| 2098 | if (DEBUG_LOCKS_WARN_ON(chain_key != 0)) |
| 2099 | return 0; |
| 2100 | chain_head = 1; |
| 2101 | } |
| 2102 | |
| 2103 | hlock->prev_chain_key = chain_key; |
| 2104 | |
| 2105 | #ifdef CONFIG_TRACE_IRQFLAGS |
| 2106 | /* |
| 2107 | * Keep track of points where we cross into an interrupt context: |
| 2108 | */ |
| 2109 | hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) + |
| 2110 | curr->softirq_context; |
| 2111 | if (depth) { |
| 2112 | struct held_lock *prev_hlock; |
| 2113 | |
| 2114 | prev_hlock = curr->held_locks + depth-1; |
| 2115 | /* |
| 2116 | * If we cross into another context, reset the |
| 2117 | * hash key (this also prevents the checking and the |
| 2118 | * adding of the dependency to 'prev'): |
| 2119 | */ |
| 2120 | if (prev_hlock->irq_context != hlock->irq_context) { |
| 2121 | chain_key = 0; |
| 2122 | chain_head = 1; |
| 2123 | } |
| 2124 | } |
| 2125 | #endif |
| 2126 | chain_key = iterate_chain_key(chain_key, id); |
| 2127 | curr->curr_chain_key = chain_key; |
| 2128 | |
| 2129 | /* |
| 2130 | * Trylock needs to maintain the stack of held locks, but it |
| 2131 | * does not add new dependencies, because trylock can be done |
| 2132 | * in any order. |
| 2133 | * |
| 2134 | * We look up the chain_key and do the O(N^2) check and update of |
| 2135 | * the dependencies only if this is a new dependency chain. |
| 2136 | * (If lookup_chain_cache() returns with 1 it acquires |
| 2137 | * hash_lock for us) |
| 2138 | */ |
| 2139 | if (!trylock && (check == 2) && lookup_chain_cache(chain_key)) { |
| 2140 | /* |
| 2141 | * Check whether last held lock: |
| 2142 | * |
| 2143 | * - is irq-safe, if this lock is irq-unsafe |
| 2144 | * - is softirq-safe, if this lock is hardirq-unsafe |
| 2145 | * |
| 2146 | * And check whether the new lock's dependency graph |
| 2147 | * could lead back to the previous lock. |
| 2148 | * |
| 2149 | * any of these scenarios could lead to a deadlock. If |
| 2150 | * All validations |
| 2151 | */ |
| 2152 | int ret = check_deadlock(curr, hlock, lock, read); |
| 2153 | |
| 2154 | if (!ret) |
| 2155 | return 0; |
| 2156 | /* |
| 2157 | * Mark recursive read, as we jump over it when |
| 2158 | * building dependencies (just like we jump over |
| 2159 | * trylock entries): |
| 2160 | */ |
| 2161 | if (ret == 2) |
| 2162 | hlock->read = 2; |
| 2163 | /* |
| 2164 | * Add dependency only if this lock is not the head |
| 2165 | * of the chain, and if it's not a secondary read-lock: |
| 2166 | */ |
| 2167 | if (!chain_head && ret != 2) |
| 2168 | if (!check_prevs_add(curr, hlock)) |
| 2169 | return 0; |
| 2170 | __raw_spin_unlock(&hash_lock); |
| 2171 | } |
| 2172 | curr->lockdep_depth++; |
| 2173 | check_chain_key(curr); |
| 2174 | if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) { |
| 2175 | debug_locks_off(); |
| 2176 | printk("BUG: MAX_LOCK_DEPTH too low!\n"); |
| 2177 | printk("turning off the locking correctness validator.\n"); |
| 2178 | return 0; |
| 2179 | } |
| 2180 | if (unlikely(curr->lockdep_depth > max_lockdep_depth)) |
| 2181 | max_lockdep_depth = curr->lockdep_depth; |
| 2182 | |
| 2183 | return 1; |
| 2184 | } |
| 2185 | |
| 2186 | static int |
| 2187 | print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock, |
| 2188 | unsigned long ip) |
| 2189 | { |
| 2190 | if (!debug_locks_off()) |
| 2191 | return 0; |
| 2192 | if (debug_locks_silent) |
| 2193 | return 0; |
| 2194 | |
| 2195 | printk("\n=====================================\n"); |
| 2196 | printk( "[ BUG: bad unlock balance detected! ]\n"); |
| 2197 | printk( "-------------------------------------\n"); |
| 2198 | printk("%s/%d is trying to release lock (", |
| 2199 | curr->comm, curr->pid); |
| 2200 | print_lockdep_cache(lock); |
| 2201 | printk(") at:\n"); |
| 2202 | print_ip_sym(ip); |
| 2203 | printk("but there are no more locks to release!\n"); |
| 2204 | printk("\nother info that might help us debug this:\n"); |
| 2205 | lockdep_print_held_locks(curr); |
| 2206 | |
| 2207 | printk("\nstack backtrace:\n"); |
| 2208 | dump_stack(); |
| 2209 | |
| 2210 | return 0; |
| 2211 | } |
| 2212 | |
| 2213 | /* |
| 2214 | * Common debugging checks for both nested and non-nested unlock: |
| 2215 | */ |
| 2216 | static int check_unlock(struct task_struct *curr, struct lockdep_map *lock, |
| 2217 | unsigned long ip) |
| 2218 | { |
| 2219 | if (unlikely(!debug_locks)) |
| 2220 | return 0; |
| 2221 | if (DEBUG_LOCKS_WARN_ON(!irqs_disabled())) |
| 2222 | return 0; |
| 2223 | |
| 2224 | if (curr->lockdep_depth <= 0) |
| 2225 | return print_unlock_inbalance_bug(curr, lock, ip); |
| 2226 | |
| 2227 | return 1; |
| 2228 | } |
| 2229 | |
| 2230 | /* |
| 2231 | * Remove the lock to the list of currently held locks in a |
| 2232 | * potentially non-nested (out of order) manner. This is a |
| 2233 | * relatively rare operation, as all the unlock APIs default |
| 2234 | * to nested mode (which uses lock_release()): |
| 2235 | */ |
| 2236 | static int |
| 2237 | lock_release_non_nested(struct task_struct *curr, |
| 2238 | struct lockdep_map *lock, unsigned long ip) |
| 2239 | { |
| 2240 | struct held_lock *hlock, *prev_hlock; |
| 2241 | unsigned int depth; |
| 2242 | int i; |
| 2243 | |
| 2244 | /* |
| 2245 | * Check whether the lock exists in the current stack |
| 2246 | * of held locks: |
| 2247 | */ |
| 2248 | depth = curr->lockdep_depth; |
| 2249 | if (DEBUG_LOCKS_WARN_ON(!depth)) |
| 2250 | return 0; |
| 2251 | |
| 2252 | prev_hlock = NULL; |
| 2253 | for (i = depth-1; i >= 0; i--) { |
| 2254 | hlock = curr->held_locks + i; |
| 2255 | /* |
| 2256 | * We must not cross into another context: |
| 2257 | */ |
| 2258 | if (prev_hlock && prev_hlock->irq_context != hlock->irq_context) |
| 2259 | break; |
| 2260 | if (hlock->instance == lock) |
| 2261 | goto found_it; |
| 2262 | prev_hlock = hlock; |
| 2263 | } |
| 2264 | return print_unlock_inbalance_bug(curr, lock, ip); |
| 2265 | |
| 2266 | found_it: |
| 2267 | /* |
| 2268 | * We have the right lock to unlock, 'hlock' points to it. |
| 2269 | * Now we remove it from the stack, and add back the other |
| 2270 | * entries (if any), recalculating the hash along the way: |
| 2271 | */ |
| 2272 | curr->lockdep_depth = i; |
| 2273 | curr->curr_chain_key = hlock->prev_chain_key; |
| 2274 | |
| 2275 | for (i++; i < depth; i++) { |
| 2276 | hlock = curr->held_locks + i; |
| 2277 | if (!__lock_acquire(hlock->instance, |
| 2278 | hlock->class->subclass, hlock->trylock, |
| 2279 | hlock->read, hlock->check, hlock->hardirqs_off, |
| 2280 | hlock->acquire_ip)) |
| 2281 | return 0; |
| 2282 | } |
| 2283 | |
| 2284 | if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1)) |
| 2285 | return 0; |
| 2286 | return 1; |
| 2287 | } |
| 2288 | |
| 2289 | /* |
| 2290 | * Remove the lock to the list of currently held locks - this gets |
| 2291 | * called on mutex_unlock()/spin_unlock*() (or on a failed |
| 2292 | * mutex_lock_interruptible()). This is done for unlocks that nest |
| 2293 | * perfectly. (i.e. the current top of the lock-stack is unlocked) |
| 2294 | */ |
| 2295 | static int lock_release_nested(struct task_struct *curr, |
| 2296 | struct lockdep_map *lock, unsigned long ip) |
| 2297 | { |
| 2298 | struct held_lock *hlock; |
| 2299 | unsigned int depth; |
| 2300 | |
| 2301 | /* |
| 2302 | * Pop off the top of the lock stack: |
| 2303 | */ |
| 2304 | depth = curr->lockdep_depth - 1; |
| 2305 | hlock = curr->held_locks + depth; |
| 2306 | |
| 2307 | /* |
| 2308 | * Is the unlock non-nested: |
| 2309 | */ |
| 2310 | if (hlock->instance != lock) |
| 2311 | return lock_release_non_nested(curr, lock, ip); |
| 2312 | curr->lockdep_depth--; |
| 2313 | |
| 2314 | if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0))) |
| 2315 | return 0; |
| 2316 | |
| 2317 | curr->curr_chain_key = hlock->prev_chain_key; |
| 2318 | |
| 2319 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2320 | hlock->prev_chain_key = 0; |
| 2321 | hlock->class = NULL; |
| 2322 | hlock->acquire_ip = 0; |
| 2323 | hlock->irq_context = 0; |
| 2324 | #endif |
| 2325 | return 1; |
| 2326 | } |
| 2327 | |
| 2328 | /* |
| 2329 | * Remove the lock to the list of currently held locks - this gets |
| 2330 | * called on mutex_unlock()/spin_unlock*() (or on a failed |
| 2331 | * mutex_lock_interruptible()). This is done for unlocks that nest |
| 2332 | * perfectly. (i.e. the current top of the lock-stack is unlocked) |
| 2333 | */ |
| 2334 | static void |
| 2335 | __lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
| 2336 | { |
| 2337 | struct task_struct *curr = current; |
| 2338 | |
| 2339 | if (!check_unlock(curr, lock, ip)) |
| 2340 | return; |
| 2341 | |
| 2342 | if (nested) { |
| 2343 | if (!lock_release_nested(curr, lock, ip)) |
| 2344 | return; |
| 2345 | } else { |
| 2346 | if (!lock_release_non_nested(curr, lock, ip)) |
| 2347 | return; |
| 2348 | } |
| 2349 | |
| 2350 | check_chain_key(curr); |
| 2351 | } |
| 2352 | |
| 2353 | /* |
| 2354 | * Check whether we follow the irq-flags state precisely: |
| 2355 | */ |
| 2356 | static void check_flags(unsigned long flags) |
| 2357 | { |
| 2358 | #if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS) |
| 2359 | if (!debug_locks) |
| 2360 | return; |
| 2361 | |
| 2362 | if (irqs_disabled_flags(flags)) |
| 2363 | DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled); |
| 2364 | else |
| 2365 | DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled); |
| 2366 | |
| 2367 | /* |
| 2368 | * We dont accurately track softirq state in e.g. |
| 2369 | * hardirq contexts (such as on 4KSTACKS), so only |
| 2370 | * check if not in hardirq contexts: |
| 2371 | */ |
| 2372 | if (!hardirq_count()) { |
| 2373 | if (softirq_count()) |
| 2374 | DEBUG_LOCKS_WARN_ON(current->softirqs_enabled); |
| 2375 | else |
| 2376 | DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled); |
| 2377 | } |
| 2378 | |
| 2379 | if (!debug_locks) |
| 2380 | print_irqtrace_events(current); |
| 2381 | #endif |
| 2382 | } |
| 2383 | |
| 2384 | /* |
| 2385 | * We are not always called with irqs disabled - do that here, |
| 2386 | * and also avoid lockdep recursion: |
| 2387 | */ |
| 2388 | void lock_acquire(struct lockdep_map *lock, unsigned int subclass, |
| 2389 | int trylock, int read, int check, unsigned long ip) |
| 2390 | { |
| 2391 | unsigned long flags; |
| 2392 | |
| 2393 | if (unlikely(current->lockdep_recursion)) |
| 2394 | return; |
| 2395 | |
| 2396 | raw_local_irq_save(flags); |
| 2397 | check_flags(flags); |
| 2398 | |
| 2399 | current->lockdep_recursion = 1; |
| 2400 | __lock_acquire(lock, subclass, trylock, read, check, |
| 2401 | irqs_disabled_flags(flags), ip); |
| 2402 | current->lockdep_recursion = 0; |
| 2403 | raw_local_irq_restore(flags); |
| 2404 | } |
| 2405 | |
| 2406 | EXPORT_SYMBOL_GPL(lock_acquire); |
| 2407 | |
| 2408 | void lock_release(struct lockdep_map *lock, int nested, unsigned long ip) |
| 2409 | { |
| 2410 | unsigned long flags; |
| 2411 | |
| 2412 | if (unlikely(current->lockdep_recursion)) |
| 2413 | return; |
| 2414 | |
| 2415 | raw_local_irq_save(flags); |
| 2416 | check_flags(flags); |
| 2417 | current->lockdep_recursion = 1; |
| 2418 | __lock_release(lock, nested, ip); |
| 2419 | current->lockdep_recursion = 0; |
| 2420 | raw_local_irq_restore(flags); |
| 2421 | } |
| 2422 | |
| 2423 | EXPORT_SYMBOL_GPL(lock_release); |
| 2424 | |
| 2425 | /* |
| 2426 | * Used by the testsuite, sanitize the validator state |
| 2427 | * after a simulated failure: |
| 2428 | */ |
| 2429 | |
| 2430 | void lockdep_reset(void) |
| 2431 | { |
| 2432 | unsigned long flags; |
| 2433 | |
| 2434 | raw_local_irq_save(flags); |
| 2435 | current->curr_chain_key = 0; |
| 2436 | current->lockdep_depth = 0; |
| 2437 | current->lockdep_recursion = 0; |
| 2438 | memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock)); |
| 2439 | nr_hardirq_chains = 0; |
| 2440 | nr_softirq_chains = 0; |
| 2441 | nr_process_chains = 0; |
| 2442 | debug_locks = 1; |
| 2443 | raw_local_irq_restore(flags); |
| 2444 | } |
| 2445 | |
| 2446 | static void zap_class(struct lock_class *class) |
| 2447 | { |
| 2448 | int i; |
| 2449 | |
| 2450 | /* |
| 2451 | * Remove all dependencies this lock is |
| 2452 | * involved in: |
| 2453 | */ |
| 2454 | for (i = 0; i < nr_list_entries; i++) { |
| 2455 | if (list_entries[i].class == class) |
| 2456 | list_del_rcu(&list_entries[i].entry); |
| 2457 | } |
| 2458 | /* |
| 2459 | * Unhash the class and remove it from the all_lock_classes list: |
| 2460 | */ |
| 2461 | list_del_rcu(&class->hash_entry); |
| 2462 | list_del_rcu(&class->lock_entry); |
| 2463 | |
| 2464 | } |
| 2465 | |
| 2466 | static inline int within(void *addr, void *start, unsigned long size) |
| 2467 | { |
| 2468 | return addr >= start && addr < start + size; |
| 2469 | } |
| 2470 | |
| 2471 | void lockdep_free_key_range(void *start, unsigned long size) |
| 2472 | { |
| 2473 | struct lock_class *class, *next; |
| 2474 | struct list_head *head; |
| 2475 | unsigned long flags; |
| 2476 | int i; |
| 2477 | |
| 2478 | raw_local_irq_save(flags); |
| 2479 | __raw_spin_lock(&hash_lock); |
| 2480 | |
| 2481 | /* |
| 2482 | * Unhash all classes that were created by this module: |
| 2483 | */ |
| 2484 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
| 2485 | head = classhash_table + i; |
| 2486 | if (list_empty(head)) |
| 2487 | continue; |
| 2488 | list_for_each_entry_safe(class, next, head, hash_entry) |
| 2489 | if (within(class->key, start, size)) |
| 2490 | zap_class(class); |
| 2491 | } |
| 2492 | |
| 2493 | __raw_spin_unlock(&hash_lock); |
| 2494 | raw_local_irq_restore(flags); |
| 2495 | } |
| 2496 | |
| 2497 | void lockdep_reset_lock(struct lockdep_map *lock) |
| 2498 | { |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2499 | struct lock_class *class, *next; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2500 | struct list_head *head; |
| 2501 | unsigned long flags; |
| 2502 | int i, j; |
| 2503 | |
| 2504 | raw_local_irq_save(flags); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2505 | |
| 2506 | /* |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2507 | * Remove all classes this lock might have: |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2508 | */ |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2509 | for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) { |
| 2510 | /* |
| 2511 | * If the class exists we look it up and zap it: |
| 2512 | */ |
| 2513 | class = look_up_lock_class(lock, j); |
| 2514 | if (class) |
| 2515 | zap_class(class); |
| 2516 | } |
| 2517 | /* |
| 2518 | * Debug check: in the end all mapped classes should |
| 2519 | * be gone. |
| 2520 | */ |
| 2521 | __raw_spin_lock(&hash_lock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2522 | for (i = 0; i < CLASSHASH_SIZE; i++) { |
| 2523 | head = classhash_table + i; |
| 2524 | if (list_empty(head)) |
| 2525 | continue; |
| 2526 | list_for_each_entry_safe(class, next, head, hash_entry) { |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2527 | if (unlikely(class == lock->class_cache)) { |
| 2528 | __raw_spin_unlock(&hash_lock); |
| 2529 | DEBUG_LOCKS_WARN_ON(1); |
| 2530 | goto out_restore; |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2531 | } |
| 2532 | } |
| 2533 | } |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2534 | __raw_spin_unlock(&hash_lock); |
Ingo Molnar | d6d897c | 2006-07-10 04:44:04 -0700 | [diff] [blame] | 2535 | |
| 2536 | out_restore: |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2537 | raw_local_irq_restore(flags); |
| 2538 | } |
| 2539 | |
| 2540 | void __init lockdep_init(void) |
| 2541 | { |
| 2542 | int i; |
| 2543 | |
| 2544 | /* |
| 2545 | * Some architectures have their own start_kernel() |
| 2546 | * code which calls lockdep_init(), while we also |
| 2547 | * call lockdep_init() from the start_kernel() itself, |
| 2548 | * and we want to initialize the hashes only once: |
| 2549 | */ |
| 2550 | if (lockdep_initialized) |
| 2551 | return; |
| 2552 | |
| 2553 | for (i = 0; i < CLASSHASH_SIZE; i++) |
| 2554 | INIT_LIST_HEAD(classhash_table + i); |
| 2555 | |
| 2556 | for (i = 0; i < CHAINHASH_SIZE; i++) |
| 2557 | INIT_LIST_HEAD(chainhash_table + i); |
| 2558 | |
| 2559 | lockdep_initialized = 1; |
| 2560 | } |
| 2561 | |
| 2562 | void __init lockdep_info(void) |
| 2563 | { |
| 2564 | printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n"); |
| 2565 | |
| 2566 | printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES); |
| 2567 | printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH); |
| 2568 | printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS); |
| 2569 | printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE); |
| 2570 | printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES); |
| 2571 | printk("... MAX_LOCKDEP_CHAINS: %lu\n", MAX_LOCKDEP_CHAINS); |
| 2572 | printk("... CHAINHASH_SIZE: %lu\n", CHAINHASH_SIZE); |
| 2573 | |
| 2574 | printk(" memory used by lock dependency info: %lu kB\n", |
| 2575 | (sizeof(struct lock_class) * MAX_LOCKDEP_KEYS + |
| 2576 | sizeof(struct list_head) * CLASSHASH_SIZE + |
| 2577 | sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES + |
| 2578 | sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS + |
| 2579 | sizeof(struct list_head) * CHAINHASH_SIZE) / 1024); |
| 2580 | |
| 2581 | printk(" per task-struct memory footprint: %lu bytes\n", |
| 2582 | sizeof(struct held_lock) * MAX_LOCK_DEPTH); |
| 2583 | |
| 2584 | #ifdef CONFIG_DEBUG_LOCKDEP |
| 2585 | if (lockdep_init_error) |
| 2586 | printk("WARNING: lockdep init error! Arch code didnt call lockdep_init() early enough?\n"); |
| 2587 | #endif |
| 2588 | } |
| 2589 | |
| 2590 | static inline int in_range(const void *start, const void *addr, const void *end) |
| 2591 | { |
| 2592 | return addr >= start && addr <= end; |
| 2593 | } |
| 2594 | |
| 2595 | static void |
| 2596 | 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] | 2597 | const void *mem_to, struct held_lock *hlock) |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2598 | { |
| 2599 | if (!debug_locks_off()) |
| 2600 | return; |
| 2601 | if (debug_locks_silent) |
| 2602 | return; |
| 2603 | |
| 2604 | printk("\n=========================\n"); |
| 2605 | printk( "[ BUG: held lock freed! ]\n"); |
| 2606 | printk( "-------------------------\n"); |
| 2607 | printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n", |
| 2608 | curr->comm, curr->pid, mem_from, mem_to-1); |
Arjan van de Ven | 55794a4 | 2006-07-10 04:44:03 -0700 | [diff] [blame] | 2609 | print_lock(hlock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2610 | lockdep_print_held_locks(curr); |
| 2611 | |
| 2612 | printk("\nstack backtrace:\n"); |
| 2613 | dump_stack(); |
| 2614 | } |
| 2615 | |
| 2616 | /* |
| 2617 | * Called when kernel memory is freed (or unmapped), or if a lock |
| 2618 | * is destroyed or reinitialized - this code checks whether there is |
| 2619 | * any held lock in the memory range of <from> to <to>: |
| 2620 | */ |
| 2621 | void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len) |
| 2622 | { |
| 2623 | const void *mem_to = mem_from + mem_len, *lock_from, *lock_to; |
| 2624 | struct task_struct *curr = current; |
| 2625 | struct held_lock *hlock; |
| 2626 | unsigned long flags; |
| 2627 | int i; |
| 2628 | |
| 2629 | if (unlikely(!debug_locks)) |
| 2630 | return; |
| 2631 | |
| 2632 | local_irq_save(flags); |
| 2633 | for (i = 0; i < curr->lockdep_depth; i++) { |
| 2634 | hlock = curr->held_locks + i; |
| 2635 | |
| 2636 | lock_from = (void *)hlock->instance; |
| 2637 | lock_to = (void *)(hlock->instance + 1); |
| 2638 | |
| 2639 | if (!in_range(mem_from, lock_from, mem_to) && |
| 2640 | !in_range(mem_from, lock_to, mem_to)) |
| 2641 | continue; |
| 2642 | |
Arjan van de Ven | 55794a4 | 2006-07-10 04:44:03 -0700 | [diff] [blame] | 2643 | print_freed_lock_bug(curr, mem_from, mem_to, hlock); |
Ingo Molnar | fbb9ce95 | 2006-07-03 00:24:50 -0700 | [diff] [blame] | 2644 | break; |
| 2645 | } |
| 2646 | local_irq_restore(flags); |
| 2647 | } |
| 2648 | |
| 2649 | static void print_held_locks_bug(struct task_struct *curr) |
| 2650 | { |
| 2651 | if (!debug_locks_off()) |
| 2652 | return; |
| 2653 | if (debug_locks_silent) |
| 2654 | return; |
| 2655 | |
| 2656 | printk("\n=====================================\n"); |
| 2657 | printk( "[ BUG: lock held at task exit time! ]\n"); |
| 2658 | printk( "-------------------------------------\n"); |
| 2659 | printk("%s/%d is exiting with locks still held!\n", |
| 2660 | curr->comm, curr->pid); |
| 2661 | lockdep_print_held_locks(curr); |
| 2662 | |
| 2663 | printk("\nstack backtrace:\n"); |
| 2664 | dump_stack(); |
| 2665 | } |
| 2666 | |
| 2667 | void debug_check_no_locks_held(struct task_struct *task) |
| 2668 | { |
| 2669 | if (unlikely(task->lockdep_depth > 0)) |
| 2670 | print_held_locks_bug(task); |
| 2671 | } |
| 2672 | |
| 2673 | void debug_show_all_locks(void) |
| 2674 | { |
| 2675 | struct task_struct *g, *p; |
| 2676 | int count = 10; |
| 2677 | int unlock = 1; |
| 2678 | |
| 2679 | printk("\nShowing all locks held in the system:\n"); |
| 2680 | |
| 2681 | /* |
| 2682 | * Here we try to get the tasklist_lock as hard as possible, |
| 2683 | * if not successful after 2 seconds we ignore it (but keep |
| 2684 | * trying). This is to enable a debug printout even if a |
| 2685 | * tasklist_lock-holding task deadlocks or crashes. |
| 2686 | */ |
| 2687 | retry: |
| 2688 | if (!read_trylock(&tasklist_lock)) { |
| 2689 | if (count == 10) |
| 2690 | printk("hm, tasklist_lock locked, retrying... "); |
| 2691 | if (count) { |
| 2692 | count--; |
| 2693 | printk(" #%d", 10-count); |
| 2694 | mdelay(200); |
| 2695 | goto retry; |
| 2696 | } |
| 2697 | printk(" ignoring it.\n"); |
| 2698 | unlock = 0; |
| 2699 | } |
| 2700 | if (count != 10) |
| 2701 | printk(" locked it.\n"); |
| 2702 | |
| 2703 | do_each_thread(g, p) { |
| 2704 | if (p->lockdep_depth) |
| 2705 | lockdep_print_held_locks(p); |
| 2706 | if (!unlock) |
| 2707 | if (read_trylock(&tasklist_lock)) |
| 2708 | unlock = 1; |
| 2709 | } while_each_thread(g, p); |
| 2710 | |
| 2711 | printk("\n"); |
| 2712 | printk("=============================================\n\n"); |
| 2713 | |
| 2714 | if (unlock) |
| 2715 | read_unlock(&tasklist_lock); |
| 2716 | } |
| 2717 | |
| 2718 | EXPORT_SYMBOL_GPL(debug_show_all_locks); |
| 2719 | |
| 2720 | void debug_show_held_locks(struct task_struct *task) |
| 2721 | { |
| 2722 | lockdep_print_held_locks(task); |
| 2723 | } |
| 2724 | |
| 2725 | EXPORT_SYMBOL_GPL(debug_show_held_locks); |
| 2726 | |