lib/debugobjects.c

   1 /*
   2  * Generic infrastructure for lifetime debugging of objects.
   3  *
   4  * Started by Thomas Gleixner
   5  *
   6  * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
   7  *
   8  * For licencing details see kernel-base/COPYING
   9  */
  10 #include <linux/debugobjects.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/sched.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/debugfs.h>
  15 #include <linux/slab.h>
  16 #include <linux/hash.h>
  17
  18 #define ODEBUG_HASH_BITS        14
  19 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  20
  21 #define ODEBUG_POOL_SIZE        512
  22 #define ODEBUG_POOL_MIN_LEVEL   256
  23
  24 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  25 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  26 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  27
  28 struct debug_bucket {
  29         struct hlist_head       list;
  30         raw_spinlock_t          lock;
  31 };
  32
  33 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  34
  35 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  36
  37 static DEFINE_RAW_SPINLOCK(pool_lock);
  38
  39 static HLIST_HEAD(obj_pool);
  40
  41 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  42 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  43 static int                      obj_pool_used;
  44 static int                      obj_pool_max_used;
  45 static struct kmem_cache        *obj_cache;
  46
  47 static int                      debug_objects_maxchain __read_mostly;
  48 static int                      debug_objects_fixups __read_mostly;
  49 static int                      debug_objects_warnings __read_mostly;
  50 static int                      debug_objects_enabled __read_mostly
  51                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  52
  53 static struct debug_obj_descr   *descr_test  __read_mostly;
  54
  55 static void free_obj_work(struct work_struct *work);
  56 static DECLARE_WORK(debug_obj_work, free_obj_work);
  57
  58 static int __init enable_object_debug(char *str)
  59 {
  60         debug_objects_enabled = 1;
  61         return 0;
  62 }
  63
  64 static int __init disable_object_debug(char *str)
  65 {
  66         debug_objects_enabled = 0;
  67         return 0;
  68 }
  69
  70 early_param("debug_objects", enable_object_debug);
  71 early_param("no_debug_objects", disable_object_debug);
  72
  73 static const char *obj_states[ODEBUG_STATE_MAX] = {
  74         [ODEBUG_STATE_NONE]             = "none",
  75         [ODEBUG_STATE_INIT]             = "initialized",
  76         [ODEBUG_STATE_INACTIVE]         = "inactive",
  77         [ODEBUG_STATE_ACTIVE]           = "active",
  78         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  79         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  80 };
  81
  82 static void fill_pool(void)
  83 {
  84         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  85         struct debug_obj *new;
  86         unsigned long flags;
  87
  88         if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
  89                 return;
  90
  91         if (unlikely(!obj_cache))
  92                 return;
  93
  94         while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
  95
  96                 new = kmem_cache_zalloc(obj_cache, gfp);
  97                 if (!new)
  98                         return;
  99
 100                 raw_spin_lock_irqsave(&pool_lock, flags);
 101                 hlist_add_head(&new->node, &obj_pool);
 102                 obj_pool_free++;
 103                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 104         }
 105 }
 106
 107 /*
 108  * Lookup an object in the hash bucket.
 109  */
 110 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 111 {
 112         struct hlist_node *node;
 113         struct debug_obj *obj;
 114         int cnt = 0;
 115
 116         hlist_for_each_entry(obj, node, &b->list, node) {
 117                 cnt++;
 118                 if (obj->object == addr)
 119                         return obj;
 120         }
 121         if (cnt > debug_objects_maxchain)
 122                 debug_objects_maxchain = cnt;
 123
 124         return NULL;
 125 }
 126
 127 /*
 128  * Allocate a new object. If the pool is empty, switch off the debugger.
 129  * Must be called with interrupts disabled.
 130  */
 131 static struct debug_obj *
 132 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 133 {
 134         struct debug_obj *obj = NULL;
 135
 136         raw_spin_lock(&pool_lock);
 137         if (obj_pool.first) {
 138                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 139
 140                 obj->object = addr;
 141                 obj->descr  = descr;
 142                 obj->state  = ODEBUG_STATE_NONE;
 143                 obj->astate = 0;
 144                 hlist_del(&obj->node);
 145
 146                 hlist_add_head(&obj->node, &b->list);
 147
 148                 obj_pool_used++;
 149                 if (obj_pool_used > obj_pool_max_used)
 150                         obj_pool_max_used = obj_pool_used;
 151
 152                 obj_pool_free--;
 153                 if (obj_pool_free < obj_pool_min_free)
 154                         obj_pool_min_free = obj_pool_free;
 155         }
 156         raw_spin_unlock(&pool_lock);
 157
 158         return obj;
 159 }
 160
 161 /*
 162  * workqueue function to free objects.
 163  */
 164 static void free_obj_work(struct work_struct *work)
 165 {
 166         struct debug_obj *obj;
 167         unsigned long flags;
 168
 169         raw_spin_lock_irqsave(&pool_lock, flags);
 170         while (obj_pool_free > ODEBUG_POOL_SIZE) {
 171                 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
 172                 hlist_del(&obj->node);
 173                 obj_pool_free--;
 174                 /*
 175                  * We release pool_lock across kmem_cache_free() to
 176                  * avoid contention on pool_lock.
 177                  */
 178                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 179                 kmem_cache_free(obj_cache, obj);
 180                 raw_spin_lock_irqsave(&pool_lock, flags);
 181         }
 182         raw_spin_unlock_irqrestore(&pool_lock, flags);
 183 }
 184
 185 /*
 186  * Put the object back into the pool and schedule work to free objects
 187  * if necessary.
 188  */
 189 static void free_object(struct debug_obj *obj)
 190 {
 191         unsigned long flags;
 192         int sched = 0;
 193
 194         raw_spin_lock_irqsave(&pool_lock, flags);
 195         /*
 196          * schedule work when the pool is filled and the cache is
 197          * initialized:
 198          */
 199         if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
 200                 sched = keventd_up() && !work_pending(&debug_obj_work);
 201         hlist_add_head(&obj->node, &obj_pool);
 202         obj_pool_free++;
 203         obj_pool_used--;
 204         raw_spin_unlock_irqrestore(&pool_lock, flags);
 205         if (sched)
 206                 schedule_work(&debug_obj_work);
 207 }
 208
 209 /*
 210  * We run out of memory. That means we probably have tons of objects
 211  * allocated.
 212  */
 213 static void debug_objects_oom(void)
 214 {
 215         struct debug_bucket *db = obj_hash;
 216         struct hlist_node *node, *tmp;
 217         HLIST_HEAD(freelist);
 218         struct debug_obj *obj;
 219         unsigned long flags;
 220         int i;
 221
 222         printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");
 223
 224         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 225                 raw_spin_lock_irqsave(&db->lock, flags);
 226                 hlist_move_list(&db->list, &freelist);
 227                 raw_spin_unlock_irqrestore(&db->lock, flags);
 228
 229                 /* Now free them */
 230                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 231                         hlist_del(&obj->node);
 232                         free_object(obj);
 233                 }
 234         }
 235 }
 236
 237 /*
 238  * We use the pfn of the address for the hash. That way we can check
 239  * for freed objects simply by checking the affected bucket.
 240  */
 241 static struct debug_bucket *get_bucket(unsigned long addr)
 242 {
 243         unsigned long hash;
 244
 245         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 246         return &obj_hash[hash];
 247 }
 248
 249 static void debug_print_object(struct debug_obj *obj, char *msg)
 250 {
 251         struct debug_obj_descr *descr = obj->descr;
 252         static int limit;
 253
 254         if (limit < 5 && descr != descr_test) {
 255                 void *hint = descr->debug_hint ?
 256                         descr->debug_hint(obj->object) : NULL;
 257                 limit++;
 258                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 259                                  "object type: %s hint: %pS\n",
 260                         msg, obj_states[obj->state], obj->astate,
 261                         descr->name, hint);
 262         }
 263         debug_objects_warnings++;
 264 }
 265
 266 /*
 267  * Try to repair the damage, so we have a better chance to get useful
 268  * debug output.
 269  */
 270 static int
 271 debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
 272                    void * addr, enum debug_obj_state state)
 273 {
 274         int fixed = 0;
 275
 276         if (fixup)
 277                 fixed = fixup(addr, state);
 278         debug_objects_fixups += fixed;
 279         return fixed;
 280 }
 281
 282 static void debug_object_is_on_stack(void *addr, int onstack)
 283 {
 284         int is_on_stack;
 285         static int limit;
 286
 287         if (limit > 4)
 288                 return;
 289
 290         is_on_stack = object_is_on_stack(addr);
 291         if (is_on_stack == onstack)
 292                 return;
 293
 294         limit++;
 295         if (is_on_stack)
 296                 printk(KERN_WARNING
 297                        "ODEBUG: object is on stack, but not annotated\n");
 298         else
 299                 printk(KERN_WARNING
 300                        "ODEBUG: object is not on stack, but annotated\n");
 301         WARN_ON(1);
 302 }
 303
 304 static void
 305 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 306 {
 307         enum debug_obj_state state;
 308         struct debug_bucket *db;
 309         struct debug_obj *obj;
 310         unsigned long flags;
 311
 312         fill_pool();
 313
 314         db = get_bucket((unsigned long) addr);
 315
 316         raw_spin_lock_irqsave(&db->lock, flags);
 317
 318         obj = lookup_object(addr, db);
 319         if (!obj) {
 320                 obj = alloc_object(addr, db, descr);
 321                 if (!obj) {
 322                         debug_objects_enabled = 0;
 323                         raw_spin_unlock_irqrestore(&db->lock, flags);
 324                         debug_objects_oom();
 325                         return;
 326                 }
 327                 debug_object_is_on_stack(addr, onstack);
 328         }
 329
 330         switch (obj->state) {
 331         case ODEBUG_STATE_NONE:
 332         case ODEBUG_STATE_INIT:
 333         case ODEBUG_STATE_INACTIVE:
 334                 obj->state = ODEBUG_STATE_INIT;
 335                 break;
 336
 337         case ODEBUG_STATE_ACTIVE:
 338                 debug_print_object(obj, "init");
 339                 state = obj->state;
 340                 raw_spin_unlock_irqrestore(&db->lock, flags);
 341                 debug_object_fixup(descr->fixup_init, addr, state);
 342                 return;
 343
 344         case ODEBUG_STATE_DESTROYED:
 345                 debug_print_object(obj, "init");
 346                 break;
 347         default:
 348                 break;
 349         }
 350
 351         raw_spin_unlock_irqrestore(&db->lock, flags);
 352 }
 353
 354 /**
 355  * debug_object_init - debug checks when an object is initialized
 356  * @addr:       address of the object
 357  * @descr:      pointer to an object specific debug description structure
 358  */
 359 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 360 {
 361         if (!debug_objects_enabled)
 362                 return;
 363
 364         __debug_object_init(addr, descr, 0);
 365 }
 366
 367 /**
 368  * debug_object_init_on_stack - debug checks when an object on stack is
 369  *                              initialized
 370  * @addr:       address of the object
 371  * @descr:      pointer to an object specific debug description structure
 372  */
 373 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 374 {
 375         if (!debug_objects_enabled)
 376                 return;
 377
 378         __debug_object_init(addr, descr, 1);
 379 }
 380
 381 /**
 382  * debug_object_activate - debug checks when an object is activated
 383  * @addr:       address of the object
 384  * @descr:      pointer to an object specific debug description structure
 385  */
 386 void debug_object_activate(void *addr, struct debug_obj_descr *descr)
 387 {
 388         enum debug_obj_state state;
 389         struct debug_bucket *db;
 390         struct debug_obj *obj;
 391         unsigned long flags;
 392         struct debug_obj o = { .object = addr,
 393                                .state = ODEBUG_STATE_NOTAVAILABLE,
 394                                .descr = descr };
 395
 396         if (!debug_objects_enabled)
 397                 return;
 398
 399         db = get_bucket((unsigned long) addr);
 400
 401         raw_spin_lock_irqsave(&db->lock, flags);
 402
 403         obj = lookup_object(addr, db);
 404         if (obj) {
 405                 switch (obj->state) {
 406                 case ODEBUG_STATE_INIT:
 407                 case ODEBUG_STATE_INACTIVE:
 408                         obj->state = ODEBUG_STATE_ACTIVE;
 409                         break;
 410
 411                 case ODEBUG_STATE_ACTIVE:
 412                         debug_print_object(obj, "activate");
 413                         state = obj->state;
 414                         raw_spin_unlock_irqrestore(&db->lock, flags);
 415                         debug_object_fixup(descr->fixup_activate, addr, state);
 416                         return;
 417
 418                 case ODEBUG_STATE_DESTROYED:
 419                         debug_print_object(obj, "activate");
 420                         break;
 421                 default:
 422                         break;
 423                 }
 424                 raw_spin_unlock_irqrestore(&db->lock, flags);
 425                 return;
 426         }
 427
 428         raw_spin_unlock_irqrestore(&db->lock, flags);
 429         /*
 430          * This happens when a static object is activated. We
 431          * let the type specific code decide whether this is
 432          * true or not.
 433          */
 434         if (debug_object_fixup(descr->fixup_activate, addr,
 435                            ODEBUG_STATE_NOTAVAILABLE))
 436                 debug_print_object(&o, "activate");
 437 }
 438
 439 /**
 440  * debug_object_deactivate - debug checks when an object is deactivated
 441  * @addr:       address of the object
 442  * @descr:      pointer to an object specific debug description structure
 443  */
 444 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 445 {
 446         struct debug_bucket *db;
 447         struct debug_obj *obj;
 448         unsigned long flags;
 449
 450         if (!debug_objects_enabled)
 451                 return;
 452
 453         db = get_bucket((unsigned long) addr);
 454
 455         raw_spin_lock_irqsave(&db->lock, flags);
 456
 457         obj = lookup_object(addr, db);
 458         if (obj) {
 459                 switch (obj->state) {
 460                 case ODEBUG_STATE_INIT:
 461                 case ODEBUG_STATE_INACTIVE:
 462                 case ODEBUG_STATE_ACTIVE:
 463                         if (!obj->astate)
 464                                 obj->state = ODEBUG_STATE_INACTIVE;
 465                         else
 466                                 debug_print_object(obj, "deactivate");
 467                         break;
 468
 469                 case ODEBUG_STATE_DESTROYED:
 470                         debug_print_object(obj, "deactivate");
 471                         break;
 472                 default:
 473                         break;
 474                 }
 475         } else {
 476                 struct debug_obj o = { .object = addr,
 477                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 478                                        .descr = descr };
 479
 480                 debug_print_object(&o, "deactivate");
 481         }
 482
 483         raw_spin_unlock_irqrestore(&db->lock, flags);
 484 }
 485
 486 /**
 487  * debug_object_destroy - debug checks when an object is destroyed
 488  * @addr:       address of the object
 489  * @descr:      pointer to an object specific debug description structure
 490  */
 491 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 492 {
 493         enum debug_obj_state state;
 494         struct debug_bucket *db;
 495         struct debug_obj *obj;
 496         unsigned long flags;
 497
 498         if (!debug_objects_enabled)
 499                 return;
 500
 501         db = get_bucket((unsigned long) addr);
 502
 503         raw_spin_lock_irqsave(&db->lock, flags);
 504
 505         obj = lookup_object(addr, db);
 506         if (!obj)
 507                 goto out_unlock;
 508
 509         switch (obj->state) {
 510         case ODEBUG_STATE_NONE:
 511         case ODEBUG_STATE_INIT:
 512         case ODEBUG_STATE_INACTIVE:
 513                 obj->state = ODEBUG_STATE_DESTROYED;
 514                 break;
 515         case ODEBUG_STATE_ACTIVE:
 516                 debug_print_object(obj, "destroy");
 517                 state = obj->state;
 518                 raw_spin_unlock_irqrestore(&db->lock, flags);
 519                 debug_object_fixup(descr->fixup_destroy, addr, state);
 520                 return;
 521
 522         case ODEBUG_STATE_DESTROYED:
 523                 debug_print_object(obj, "destroy");
 524                 break;
 525         default:
 526                 break;
 527         }
 528 out_unlock:
 529         raw_spin_unlock_irqrestore(&db->lock, flags);
 530 }
 531
 532 /**
 533  * debug_object_free - debug checks when an object is freed
 534  * @addr:       address of the object
 535  * @descr:      pointer to an object specific debug description structure
 536  */
 537 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 538 {
 539         enum debug_obj_state state;
 540         struct debug_bucket *db;
 541         struct debug_obj *obj;
 542         unsigned long flags;
 543
 544         if (!debug_objects_enabled)
 545                 return;
 546
 547         db = get_bucket((unsigned long) addr);
 548
 549         raw_spin_lock_irqsave(&db->lock, flags);
 550
 551         obj = lookup_object(addr, db);
 552         if (!obj)
 553                 goto out_unlock;
 554
 555         switch (obj->state) {
 556         case ODEBUG_STATE_ACTIVE:
 557                 debug_print_object(obj, "free");
 558                 state = obj->state;
 559                 raw_spin_unlock_irqrestore(&db->lock, flags);
 560                 debug_object_fixup(descr->fixup_free, addr, state);
 561                 return;
 562         default:
 563                 hlist_del(&obj->node);
 564                 raw_spin_unlock_irqrestore(&db->lock, flags);
 565                 free_object(obj);
 566                 return;
 567         }
 568 out_unlock:
 569         raw_spin_unlock_irqrestore(&db->lock, flags);
 570 }
 571
 572 /**
 573  * debug_object_assert_init - debug checks when object should be init-ed
 574  * @addr:       address of the object
 575  * @descr:      pointer to an object specific debug description structure
 576  */
 577 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 578 {
 579         struct debug_bucket *db;
 580         struct debug_obj *obj;
 581         unsigned long flags;
 582
 583         if (!debug_objects_enabled)
 584                 return;
 585
 586         db = get_bucket((unsigned long) addr);
 587
 588         raw_spin_lock_irqsave(&db->lock, flags);
 589
 590         obj = lookup_object(addr, db);
 591         if (!obj) {
 592                 struct debug_obj o = { .object = addr,
 593                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 594                                        .descr = descr };
 595
 596                 raw_spin_unlock_irqrestore(&db->lock, flags);
 597                 /*
 598                  * Maybe the object is static.  Let the type specific
 599                  * code decide what to do.
 600                  */
 601                 if (debug_object_fixup(descr->fixup_assert_init, addr,
 602                                        ODEBUG_STATE_NOTAVAILABLE))
 603                         debug_print_object(&o, "assert_init");
 604                 return;
 605         }
 606
 607         raw_spin_unlock_irqrestore(&db->lock, flags);
 608 }
 609
 610 /**
 611  * debug_object_active_state - debug checks object usage state machine
 612  * @addr:       address of the object
 613  * @descr:      pointer to an object specific debug description structure
 614  * @expect:     expected state
 615  * @next:       state to move to if expected state is found
 616  */
 617 void
 618 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 619                           unsigned int expect, unsigned int next)
 620 {
 621         struct debug_bucket *db;
 622         struct debug_obj *obj;
 623         unsigned long flags;
 624
 625         if (!debug_objects_enabled)
 626                 return;
 627
 628         db = get_bucket((unsigned long) addr);
 629
 630         raw_spin_lock_irqsave(&db->lock, flags);
 631
 632         obj = lookup_object(addr, db);
 633         if (obj) {
 634                 switch (obj->state) {
 635                 case ODEBUG_STATE_ACTIVE:
 636                         if (obj->astate == expect)
 637                                 obj->astate = next;
 638                         else
 639                                 debug_print_object(obj, "active_state");
 640                         break;
 641
 642                 default:
 643                         debug_print_object(obj, "active_state");
 644                         break;
 645                 }
 646         } else {
 647                 struct debug_obj o = { .object = addr,
 648                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 649                                        .descr = descr };
 650
 651                 debug_print_object(&o, "active_state");
 652         }
 653
 654         raw_spin_unlock_irqrestore(&db->lock, flags);
 655 }
 656
 657 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 658 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 659 {
 660         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 661         struct hlist_node *node, *tmp;
 662         HLIST_HEAD(freelist);
 663         struct debug_obj_descr *descr;
 664         enum debug_obj_state state;
 665         struct debug_bucket *db;
 666         struct debug_obj *obj;
 667         int cnt;
 668
 669         saddr = (unsigned long) address;
 670         eaddr = saddr + size;
 671         paddr = saddr & ODEBUG_CHUNK_MASK;
 672         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 673         chunks >>= ODEBUG_CHUNK_SHIFT;
 674
 675         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 676                 db = get_bucket(paddr);
 677
 678 repeat:
 679                 cnt = 0;
 680                 raw_spin_lock_irqsave(&db->lock, flags);
 681                 hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
 682                         cnt++;
 683                         oaddr = (unsigned long) obj->object;
 684                         if (oaddr < saddr || oaddr >= eaddr)
 685                                 continue;
 686
 687                         switch (obj->state) {
 688                         case ODEBUG_STATE_ACTIVE:
 689                                 debug_print_object(obj, "free");
 690                                 descr = obj->descr;
 691                                 state = obj->state;
 692                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 693                                 debug_object_fixup(descr->fixup_free,
 694                                                    (void *) oaddr, state);
 695                                 goto repeat;
 696                         default:
 697                                 hlist_del(&obj->node);
 698                                 hlist_add_head(&obj->node, &freelist);
 699                                 break;
 700                         }
 701                 }
 702                 raw_spin_unlock_irqrestore(&db->lock, flags);
 703
 704                 /* Now free them */
 705                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 706                         hlist_del(&obj->node);
 707                         free_object(obj);
 708                 }
 709
 710                 if (cnt > debug_objects_maxchain)
 711                         debug_objects_maxchain = cnt;
 712         }
 713 }
 714
 715 void debug_check_no_obj_freed(const void *address, unsigned long size)
 716 {
 717         if (debug_objects_enabled)
 718                 __debug_check_no_obj_freed(address, size);
 719 }
 720 #endif
 721
 722 #ifdef CONFIG_DEBUG_FS
 723
 724 static int debug_stats_show(struct seq_file *m, void *v)
 725 {
 726         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 727         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 728         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 729         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 730         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 731         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 732         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 733         return 0;
 734 }
 735
 736 static int debug_stats_open(struct inode *inode, struct file *filp)
 737 {
 738         return single_open(filp, debug_stats_show, NULL);
 739 }
 740
 741 static const struct file_operations debug_stats_fops = {
 742         .open           = debug_stats_open,
 743         .read           = seq_read,
 744         .llseek         = seq_lseek,
 745         .release        = single_release,
 746 };
 747
 748 static int __init debug_objects_init_debugfs(void)
 749 {
 750         struct dentry *dbgdir, *dbgstats;
 751
 752         if (!debug_objects_enabled)
 753                 return 0;
 754
 755         dbgdir = debugfs_create_dir("debug_objects", NULL);
 756         if (!dbgdir)
 757                 return -ENOMEM;
 758
 759         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 760                                        &debug_stats_fops);
 761         if (!dbgstats)
 762                 goto err;
 763
 764         return 0;
 765
 766 err:
 767         debugfs_remove(dbgdir);
 768
 769         return -ENOMEM;
 770 }
 771 __initcall(debug_objects_init_debugfs);
 772
 773 #else
 774 static inline void debug_objects_init_debugfs(void) { }
 775 #endif
 776
 777 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 778
 779 /* Random data structure for the self test */
 780 struct self_test {
 781         unsigned long   dummy1[6];
 782         int             static_init;
 783         unsigned long   dummy2[3];
 784 };
 785
 786 static __initdata struct debug_obj_descr descr_type_test;
 787
 788 /*
 789  * fixup_init is called when:
 790  * - an active object is initialized
 791  */
 792 static int __init fixup_init(void *addr, enum debug_obj_state state)
 793 {
 794         struct self_test *obj = addr;
 795
 796         switch (state) {
 797         case ODEBUG_STATE_ACTIVE:
 798                 debug_object_deactivate(obj, &descr_type_test);
 799                 debug_object_init(obj, &descr_type_test);
 800                 return 1;
 801         default:
 802                 return 0;
 803         }
 804 }
 805
 806 /*
 807  * fixup_activate is called when:
 808  * - an active object is activated
 809  * - an unknown object is activated (might be a statically initialized object)
 810  */
 811 static int __init fixup_activate(void *addr, enum debug_obj_state state)
 812 {
 813         struct self_test *obj = addr;
 814
 815         switch (state) {
 816         case ODEBUG_STATE_NOTAVAILABLE:
 817                 if (obj->static_init == 1) {
 818                         debug_object_init(obj, &descr_type_test);
 819                         debug_object_activate(obj, &descr_type_test);
 820                         return 0;
 821                 }
 822                 return 1;
 823
 824         case ODEBUG_STATE_ACTIVE:
 825                 debug_object_deactivate(obj, &descr_type_test);
 826                 debug_object_activate(obj, &descr_type_test);
 827                 return 1;
 828
 829         default:
 830                 return 0;
 831         }
 832 }
 833
 834 /*
 835  * fixup_destroy is called when:
 836  * - an active object is destroyed
 837  */
 838 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
 839 {
 840         struct self_test *obj = addr;
 841
 842         switch (state) {
 843         case ODEBUG_STATE_ACTIVE:
 844                 debug_object_deactivate(obj, &descr_type_test);
 845                 debug_object_destroy(obj, &descr_type_test);
 846                 return 1;
 847         default:
 848                 return 0;
 849         }
 850 }
 851
 852 /*
 853  * fixup_free is called when:
 854  * - an active object is freed
 855  */
 856 static int __init fixup_free(void *addr, enum debug_obj_state state)
 857 {
 858         struct self_test *obj = addr;
 859
 860         switch (state) {
 861         case ODEBUG_STATE_ACTIVE:
 862                 debug_object_deactivate(obj, &descr_type_test);
 863                 debug_object_free(obj, &descr_type_test);
 864                 return 1;
 865         default:
 866                 return 0;
 867         }
 868 }
 869
 870 static int __init
 871 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 872 {
 873         struct debug_bucket *db;
 874         struct debug_obj *obj;
 875         unsigned long flags;
 876         int res = -EINVAL;
 877
 878         db = get_bucket((unsigned long) addr);
 879
 880         raw_spin_lock_irqsave(&db->lock, flags);
 881
 882         obj = lookup_object(addr, db);
 883         if (!obj && state != ODEBUG_STATE_NONE) {
 884                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 885                 goto out;
 886         }
 887         if (obj && obj->state != state) {
 888                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 889                        obj->state, state);
 890                 goto out;
 891         }
 892         if (fixups != debug_objects_fixups) {
 893                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 894                        fixups, debug_objects_fixups);
 895                 goto out;
 896         }
 897         if (warnings != debug_objects_warnings) {
 898                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 899                        warnings, debug_objects_warnings);
 900                 goto out;
 901         }
 902         res = 0;
 903 out:
 904         raw_spin_unlock_irqrestore(&db->lock, flags);
 905         if (res)
 906                 debug_objects_enabled = 0;
 907         return res;
 908 }
 909
 910 static __initdata struct debug_obj_descr descr_type_test = {
 911         .name                   = "selftest",
 912         .fixup_init             = fixup_init,
 913         .fixup_activate         = fixup_activate,
 914         .fixup_destroy          = fixup_destroy,
 915         .fixup_free             = fixup_free,
 916 };
 917
 918 static __initdata struct self_test obj = { .static_init = 0 };
 919
 920 static void __init debug_objects_selftest(void)
 921 {
 922         int fixups, oldfixups, warnings, oldwarnings;
 923         unsigned long flags;
 924
 925         local_irq_save(flags);
 926
 927         fixups = oldfixups = debug_objects_fixups;
 928         warnings = oldwarnings = debug_objects_warnings;
 929         descr_test = &descr_type_test;
 930
 931         debug_object_init(&obj, &descr_type_test);
 932         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 933                 goto out;
 934         debug_object_activate(&obj, &descr_type_test);
 935         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 936                 goto out;
 937         debug_object_activate(&obj, &descr_type_test);
 938         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 939                 goto out;
 940         debug_object_deactivate(&obj, &descr_type_test);
 941         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 942                 goto out;
 943         debug_object_destroy(&obj, &descr_type_test);
 944         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 945                 goto out;
 946         debug_object_init(&obj, &descr_type_test);
 947         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 948                 goto out;
 949         debug_object_activate(&obj, &descr_type_test);
 950         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 951                 goto out;
 952         debug_object_deactivate(&obj, &descr_type_test);
 953         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 954                 goto out;
 955         debug_object_free(&obj, &descr_type_test);
 956         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 957                 goto out;
 958
 959         obj.static_init = 1;
 960         debug_object_activate(&obj, &descr_type_test);
 961         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 962                 goto out;
 963         debug_object_init(&obj, &descr_type_test);
 964         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
 965                 goto out;
 966         debug_object_free(&obj, &descr_type_test);
 967         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 968                 goto out;
 969
 970 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 971         debug_object_init(&obj, &descr_type_test);
 972         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 973                 goto out;
 974         debug_object_activate(&obj, &descr_type_test);
 975         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 976                 goto out;
 977         __debug_check_no_obj_freed(&obj, sizeof(obj));
 978         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
 979                 goto out;
 980 #endif
 981         printk(KERN_INFO "ODEBUG: selftest passed\n");
 982
 983 out:
 984         debug_objects_fixups = oldfixups;
 985         debug_objects_warnings = oldwarnings;
 986         descr_test = NULL;
 987
 988         local_irq_restore(flags);
 989 }
 990 #else
 991 static inline void debug_objects_selftest(void) { }
 992 #endif
 993
 994 /*
 995  * Called during early boot to initialize the hash buckets and link
 996  * the static object pool objects into the poll list. After this call
 997  * the object tracker is fully operational.
 998  */
 999 void __init debug_objects_early_init(void)
1000 {
1001         int i;
1002
1003         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1004                 raw_spin_lock_init(&obj_hash[i].lock);
1005
1006         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1007                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1008 }
1009
1010 /*
1011  * Convert the statically allocated objects to dynamic ones:
1012  */
1013 static int __init debug_objects_replace_static_objects(void)
1014 {
1015         struct debug_bucket *db = obj_hash;
1016         struct hlist_node *node, *tmp;
1017         struct debug_obj *obj, *new;
1018         HLIST_HEAD(objects);
1019         int i, cnt = 0;
1020
1021         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1022                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1023                 if (!obj)
1024                         goto free;
1025                 hlist_add_head(&obj->node, &objects);
1026         }
1027
1028         /*
1029          * When debug_objects_mem_init() is called we know that only
1030          * one CPU is up, so disabling interrupts is enough
1031          * protection. This avoids the lockdep hell of lock ordering.
1032          */
1033         local_irq_disable();
1034
1035         /* Remove the statically allocated objects from the pool */
1036         hlist_for_each_entry_safe(obj, node, tmp, &obj_pool, node)
1037                 hlist_del(&obj->node);
1038         /* Move the allocated objects to the pool */
1039         hlist_move_list(&objects, &obj_pool);
1040
1041         /* Replace the active object references */
1042         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1043                 hlist_move_list(&db->list, &objects);
1044
1045                 hlist_for_each_entry(obj, node, &objects, node) {
1046                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1047                         hlist_del(&new->node);
1048                         /* copy object data */
1049                         *new = *obj;
1050                         hlist_add_head(&new->node, &db->list);
1051                         cnt++;
1052                 }
1053         }
1054         local_irq_enable();
1055
1056         printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
1057                obj_pool_used);
1058         return 0;
1059 free:
1060         hlist_for_each_entry_safe(obj, node, tmp, &objects, node) {
1061                 hlist_del(&obj->node);
1062                 kmem_cache_free(obj_cache, obj);
1063         }
1064         return -ENOMEM;
1065 }
1066
1067 /*
1068  * Called after the kmem_caches are functional to setup a dedicated
1069  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1070  * prevents that the debug code is called on kmem_cache_free() for the
1071  * debug tracker objects to avoid recursive calls.
1072  */
1073 void __init debug_objects_mem_init(void)
1074 {
1075         if (!debug_objects_enabled)
1076                 return;
1077
1078         obj_cache = kmem_cache_create("debug_objects_cache",
1079                                       sizeof (struct debug_obj), 0,
1080                                       SLAB_DEBUG_OBJECTS, NULL);
1081
1082         if (!obj_cache || debug_objects_replace_static_objects()) {
1083                 debug_objects_enabled = 0;
1084                 if (obj_cache)
1085                         kmem_cache_destroy(obj_cache);
1086                 printk(KERN_WARNING "ODEBUG: out of memory.\n");
1087         } else
1088                 debug_objects_selftest();
1089 }