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 debug_obj *obj;
 113         int cnt = 0;
 114
 115         hlist_for_each_entry(obj, &b->list, node) {
 116                 cnt++;
 117                 if (obj->object == addr)
 118                         return obj;
 119         }
 120         if (cnt > debug_objects_maxchain)
 121                 debug_objects_maxchain = cnt;
 122
 123         return NULL;
 124 }
 125
 126 /*
 127  * Allocate a new object. If the pool is empty, switch off the debugger.
 128  * Must be called with interrupts disabled.
 129  */
 130 static struct debug_obj *
 131 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 132 {
 133         struct debug_obj *obj = NULL;
 134
 135         raw_spin_lock(&pool_lock);
 136         if (obj_pool.first) {
 137                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 138
 139                 obj->object = addr;
 140                 obj->descr  = descr;
 141                 obj->state  = ODEBUG_STATE_NONE;
 142                 obj->astate = 0;
 143                 hlist_del(&obj->node);
 144
 145                 hlist_add_head(&obj->node, &b->list);
 146
 147                 obj_pool_used++;
 148                 if (obj_pool_used > obj_pool_max_used)
 149                         obj_pool_max_used = obj_pool_used;
 150
 151                 obj_pool_free--;
 152                 if (obj_pool_free < obj_pool_min_free)
 153                         obj_pool_min_free = obj_pool_free;
 154         }
 155         raw_spin_unlock(&pool_lock);
 156
 157         return obj;
 158 }
 159
 160 /*
 161  * workqueue function to free objects.
 162  */
 163 static void free_obj_work(struct work_struct *work)
 164 {
 165         struct debug_obj *obj;
 166         unsigned long flags;
 167
 168         raw_spin_lock_irqsave(&pool_lock, flags);
 169         while (obj_pool_free > ODEBUG_POOL_SIZE) {
 170                 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
 171                 hlist_del(&obj->node);
 172                 obj_pool_free--;
 173                 /*
 174                  * We release pool_lock across kmem_cache_free() to
 175                  * avoid contention on pool_lock.
 176                  */
 177                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 178                 kmem_cache_free(obj_cache, obj);
 179                 raw_spin_lock_irqsave(&pool_lock, flags);
 180         }
 181         raw_spin_unlock_irqrestore(&pool_lock, flags);
 182 }
 183
 184 /*
 185  * Put the object back into the pool and schedule work to free objects
 186  * if necessary.
 187  */
 188 static void free_object(struct debug_obj *obj)
 189 {
 190         unsigned long flags;
 191         int sched = 0;
 192
 193         raw_spin_lock_irqsave(&pool_lock, flags);
 194         /*
 195          * schedule work when the pool is filled and the cache is
 196          * initialized:
 197          */
 198         if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
 199                 sched = keventd_up();
 200         hlist_add_head(&obj->node, &obj_pool);
 201         obj_pool_free++;
 202         obj_pool_used--;
 203         raw_spin_unlock_irqrestore(&pool_lock, flags);
 204         if (sched)
 205                 schedule_work(&debug_obj_work);
 206 }
 207
 208 /*
 209  * We run out of memory. That means we probably have tons of objects
 210  * allocated.
 211  */
 212 static void debug_objects_oom(void)
 213 {
 214         struct debug_bucket *db = obj_hash;
 215         struct hlist_node *tmp;
 216         HLIST_HEAD(freelist);
 217         struct debug_obj *obj;
 218         unsigned long flags;
 219         int i;
 220
 221         printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");
 222
 223         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 224                 raw_spin_lock_irqsave(&db->lock, flags);
 225                 hlist_move_list(&db->list, &freelist);
 226                 raw_spin_unlock_irqrestore(&db->lock, flags);
 227
 228                 /* Now free them */
 229                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 230                         hlist_del(&obj->node);
 231                         free_object(obj);
 232                 }
 233         }
 234 }
 235
 236 /*
 237  * We use the pfn of the address for the hash. That way we can check
 238  * for freed objects simply by checking the affected bucket.
 239  */
 240 static struct debug_bucket *get_bucket(unsigned long addr)
 241 {
 242         unsigned long hash;
 243
 244         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 245         return &obj_hash[hash];
 246 }
 247
 248 static void debug_print_object(struct debug_obj *obj, char *msg)
 249 {
 250         struct debug_obj_descr *descr = obj->descr;
 251         static int limit;
 252
 253         if (limit < 5 && descr != descr_test) {
 254                 void *hint = descr->debug_hint ?
 255                         descr->debug_hint(obj->object) : NULL;
 256                 limit++;
 257                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 258                                  "object type: %s hint: %pS\n",
 259                         msg, obj_states[obj->state], obj->astate,
 260                         descr->name, hint);
 261         }
 262         debug_objects_warnings++;
 263 }
 264
 265 /*
 266  * Try to repair the damage, so we have a better chance to get useful
 267  * debug output.
 268  */
 269 static int
 270 debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
 271                    void * addr, enum debug_obj_state state)
 272 {
 273         int fixed = 0;
 274
 275         if (fixup)
 276                 fixed = fixup(addr, state);
 277         debug_objects_fixups += fixed;
 278         return fixed;
 279 }
 280
 281 static void debug_object_is_on_stack(void *addr, int onstack)
 282 {
 283         int is_on_stack;
 284         static int limit;
 285
 286         if (limit > 4)
 287                 return;
 288
 289         is_on_stack = object_is_on_stack(addr);
 290         if (is_on_stack == onstack)
 291                 return;
 292
 293         limit++;
 294         if (is_on_stack)
 295                 printk(KERN_WARNING
 296                        "ODEBUG: object is on stack, but not annotated\n");
 297         else
 298                 printk(KERN_WARNING
 299                        "ODEBUG: object is not on stack, but annotated\n");
 300         WARN_ON(1);
 301 }
 302
 303 static void
 304 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 305 {
 306         enum debug_obj_state state;
 307         struct debug_bucket *db;
 308         struct debug_obj *obj;
 309         unsigned long flags;
 310
 311         fill_pool();
 312
 313         db = get_bucket((unsigned long) addr);
 314
 315         raw_spin_lock_irqsave(&db->lock, flags);
 316
 317         obj = lookup_object(addr, db);
 318         if (!obj) {
 319                 obj = alloc_object(addr, db, descr);
 320                 if (!obj) {
 321                         debug_objects_enabled = 0;
 322                         raw_spin_unlock_irqrestore(&db->lock, flags);
 323                         debug_objects_oom();
 324                         return;
 325                 }
 326                 debug_object_is_on_stack(addr, onstack);
 327         }
 328
 329         switch (obj->state) {
 330         case ODEBUG_STATE_NONE:
 331         case ODEBUG_STATE_INIT:
 332         case ODEBUG_STATE_INACTIVE:
 333                 obj->state = ODEBUG_STATE_INIT;
 334                 break;
 335
 336         case ODEBUG_STATE_ACTIVE:
 337                 debug_print_object(obj, "init");
 338                 state = obj->state;
 339                 raw_spin_unlock_irqrestore(&db->lock, flags);
 340                 debug_object_fixup(descr->fixup_init, addr, state);
 341                 return;
 342
 343         case ODEBUG_STATE_DESTROYED:
 344                 debug_print_object(obj, "init");
 345                 break;
 346         default:
 347                 break;
 348         }
 349
 350         raw_spin_unlock_irqrestore(&db->lock, flags);
 351 }
 352
 353 /**
 354  * debug_object_init - debug checks when an object is initialized
 355  * @addr:       address of the object
 356  * @descr:      pointer to an object specific debug description structure
 357  */
 358 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 359 {
 360         if (!debug_objects_enabled)
 361                 return;
 362
 363         __debug_object_init(addr, descr, 0);
 364 }
 365
 366 /**
 367  * debug_object_init_on_stack - debug checks when an object on stack is
 368  *                              initialized
 369  * @addr:       address of the object
 370  * @descr:      pointer to an object specific debug description structure
 371  */
 372 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 373 {
 374         if (!debug_objects_enabled)
 375                 return;
 376
 377         __debug_object_init(addr, descr, 1);
 378 }
 379
 380 /**
 381  * debug_object_activate - debug checks when an object is activated
 382  * @addr:       address of the object
 383  * @descr:      pointer to an object specific debug description structure
 384  * Returns 0 for success, -EINVAL for check failed.
 385  */
 386 int 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         int ret;
 393         struct debug_obj o = { .object = addr,
 394                                .state = ODEBUG_STATE_NOTAVAILABLE,
 395                                .descr = descr };
 396
 397         if (!debug_objects_enabled)
 398                 return 0;
 399
 400         db = get_bucket((unsigned long) addr);
 401
 402         raw_spin_lock_irqsave(&db->lock, flags);
 403
 404         obj = lookup_object(addr, db);
 405         if (obj) {
 406                 switch (obj->state) {
 407                 case ODEBUG_STATE_INIT:
 408                 case ODEBUG_STATE_INACTIVE:
 409                         obj->state = ODEBUG_STATE_ACTIVE;
 410                         ret = 0;
 411                         break;
 412
 413                 case ODEBUG_STATE_ACTIVE:
 414                         debug_print_object(obj, "activate");
 415                         state = obj->state;
 416                         raw_spin_unlock_irqrestore(&db->lock, flags);
 417                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 418                         return ret ? -EINVAL : 0;
 419
 420                 case ODEBUG_STATE_DESTROYED:
 421                         debug_print_object(obj, "activate");
 422                         ret = -EINVAL;
 423                         break;
 424                 default:
 425                         ret = 0;
 426                         break;
 427                 }
 428                 raw_spin_unlock_irqrestore(&db->lock, flags);
 429                 return ret;
 430         }
 431
 432         raw_spin_unlock_irqrestore(&db->lock, flags);
 433         /*
 434          * This happens when a static object is activated. We
 435          * let the type specific code decide whether this is
 436          * true or not.
 437          */
 438         if (debug_object_fixup(descr->fixup_activate, addr,
 439                            ODEBUG_STATE_NOTAVAILABLE)) {
 440                 debug_print_object(&o, "activate");
 441                 return -EINVAL;
 442         }
 443         return 0;
 444 }
 445
 446 /**
 447  * debug_object_deactivate - debug checks when an object is deactivated
 448  * @addr:       address of the object
 449  * @descr:      pointer to an object specific debug description structure
 450  */
 451 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 452 {
 453         struct debug_bucket *db;
 454         struct debug_obj *obj;
 455         unsigned long flags;
 456
 457         if (!debug_objects_enabled)
 458                 return;
 459
 460         db = get_bucket((unsigned long) addr);
 461
 462         raw_spin_lock_irqsave(&db->lock, flags);
 463
 464         obj = lookup_object(addr, db);
 465         if (obj) {
 466                 switch (obj->state) {
 467                 case ODEBUG_STATE_INIT:
 468                 case ODEBUG_STATE_INACTIVE:
 469                 case ODEBUG_STATE_ACTIVE:
 470                         if (!obj->astate)
 471                                 obj->state = ODEBUG_STATE_INACTIVE;
 472                         else
 473                                 debug_print_object(obj, "deactivate");
 474                         break;
 475
 476                 case ODEBUG_STATE_DESTROYED:
 477                         debug_print_object(obj, "deactivate");
 478                         break;
 479                 default:
 480                         break;
 481                 }
 482         } else {
 483                 struct debug_obj o = { .object = addr,
 484                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 485                                        .descr = descr };
 486
 487                 debug_print_object(&o, "deactivate");
 488         }
 489
 490         raw_spin_unlock_irqrestore(&db->lock, flags);
 491 }
 492
 493 /**
 494  * debug_object_destroy - debug checks when an object is destroyed
 495  * @addr:       address of the object
 496  * @descr:      pointer to an object specific debug description structure
 497  */
 498 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 499 {
 500         enum debug_obj_state state;
 501         struct debug_bucket *db;
 502         struct debug_obj *obj;
 503         unsigned long flags;
 504
 505         if (!debug_objects_enabled)
 506                 return;
 507
 508         db = get_bucket((unsigned long) addr);
 509
 510         raw_spin_lock_irqsave(&db->lock, flags);
 511
 512         obj = lookup_object(addr, db);
 513         if (!obj)
 514                 goto out_unlock;
 515
 516         switch (obj->state) {
 517         case ODEBUG_STATE_NONE:
 518         case ODEBUG_STATE_INIT:
 519         case ODEBUG_STATE_INACTIVE:
 520                 obj->state = ODEBUG_STATE_DESTROYED;
 521                 break;
 522         case ODEBUG_STATE_ACTIVE:
 523                 debug_print_object(obj, "destroy");
 524                 state = obj->state;
 525                 raw_spin_unlock_irqrestore(&db->lock, flags);
 526                 debug_object_fixup(descr->fixup_destroy, addr, state);
 527                 return;
 528
 529         case ODEBUG_STATE_DESTROYED:
 530                 debug_print_object(obj, "destroy");
 531                 break;
 532         default:
 533                 break;
 534         }
 535 out_unlock:
 536         raw_spin_unlock_irqrestore(&db->lock, flags);
 537 }
 538
 539 /**
 540  * debug_object_free - debug checks when an object is freed
 541  * @addr:       address of the object
 542  * @descr:      pointer to an object specific debug description structure
 543  */
 544 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 545 {
 546         enum debug_obj_state state;
 547         struct debug_bucket *db;
 548         struct debug_obj *obj;
 549         unsigned long flags;
 550
 551         if (!debug_objects_enabled)
 552                 return;
 553
 554         db = get_bucket((unsigned long) addr);
 555
 556         raw_spin_lock_irqsave(&db->lock, flags);
 557
 558         obj = lookup_object(addr, db);
 559         if (!obj)
 560                 goto out_unlock;
 561
 562         switch (obj->state) {
 563         case ODEBUG_STATE_ACTIVE:
 564                 debug_print_object(obj, "free");
 565                 state = obj->state;
 566                 raw_spin_unlock_irqrestore(&db->lock, flags);
 567                 debug_object_fixup(descr->fixup_free, addr, state);
 568                 return;
 569         default:
 570                 hlist_del(&obj->node);
 571                 raw_spin_unlock_irqrestore(&db->lock, flags);
 572                 free_object(obj);
 573                 return;
 574         }
 575 out_unlock:
 576         raw_spin_unlock_irqrestore(&db->lock, flags);
 577 }
 578
 579 /**
 580  * debug_object_assert_init - debug checks when object should be init-ed
 581  * @addr:       address of the object
 582  * @descr:      pointer to an object specific debug description structure
 583  */
 584 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 585 {
 586         struct debug_bucket *db;
 587         struct debug_obj *obj;
 588         unsigned long flags;
 589
 590         if (!debug_objects_enabled)
 591                 return;
 592
 593         db = get_bucket((unsigned long) addr);
 594
 595         raw_spin_lock_irqsave(&db->lock, flags);
 596
 597         obj = lookup_object(addr, db);
 598         if (!obj) {
 599                 struct debug_obj o = { .object = addr,
 600                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 601                                        .descr = descr };
 602
 603                 raw_spin_unlock_irqrestore(&db->lock, flags);
 604                 /*
 605                  * Maybe the object is static.  Let the type specific
 606                  * code decide what to do.
 607                  */
 608                 if (debug_object_fixup(descr->fixup_assert_init, addr,
 609                                        ODEBUG_STATE_NOTAVAILABLE))
 610                         debug_print_object(&o, "assert_init");
 611                 return;
 612         }
 613
 614         raw_spin_unlock_irqrestore(&db->lock, flags);
 615 }
 616
 617 /**
 618  * debug_object_active_state - debug checks object usage state machine
 619  * @addr:       address of the object
 620  * @descr:      pointer to an object specific debug description structure
 621  * @expect:     expected state
 622  * @next:       state to move to if expected state is found
 623  */
 624 void
 625 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 626                           unsigned int expect, unsigned int next)
 627 {
 628         struct debug_bucket *db;
 629         struct debug_obj *obj;
 630         unsigned long flags;
 631
 632         if (!debug_objects_enabled)
 633                 return;
 634
 635         db = get_bucket((unsigned long) addr);
 636
 637         raw_spin_lock_irqsave(&db->lock, flags);
 638
 639         obj = lookup_object(addr, db);
 640         if (obj) {
 641                 switch (obj->state) {
 642                 case ODEBUG_STATE_ACTIVE:
 643                         if (obj->astate == expect)
 644                                 obj->astate = next;
 645                         else
 646                                 debug_print_object(obj, "active_state");
 647                         break;
 648
 649                 default:
 650                         debug_print_object(obj, "active_state");
 651                         break;
 652                 }
 653         } else {
 654                 struct debug_obj o = { .object = addr,
 655                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 656                                        .descr = descr };
 657
 658                 debug_print_object(&o, "active_state");
 659         }
 660
 661         raw_spin_unlock_irqrestore(&db->lock, flags);
 662 }
 663
 664 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 665 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 666 {
 667         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 668         struct hlist_node *tmp;
 669         HLIST_HEAD(freelist);
 670         struct debug_obj_descr *descr;
 671         enum debug_obj_state state;
 672         struct debug_bucket *db;
 673         struct debug_obj *obj;
 674         int cnt;
 675
 676         saddr = (unsigned long) address;
 677         eaddr = saddr + size;
 678         paddr = saddr & ODEBUG_CHUNK_MASK;
 679         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 680         chunks >>= ODEBUG_CHUNK_SHIFT;
 681
 682         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 683                 db = get_bucket(paddr);
 684
 685 repeat:
 686                 cnt = 0;
 687                 raw_spin_lock_irqsave(&db->lock, flags);
 688                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 689                         cnt++;
 690                         oaddr = (unsigned long) obj->object;
 691                         if (oaddr < saddr || oaddr >= eaddr)
 692                                 continue;
 693
 694                         switch (obj->state) {
 695                         case ODEBUG_STATE_ACTIVE:
 696                                 debug_print_object(obj, "free");
 697                                 descr = obj->descr;
 698                                 state = obj->state;
 699                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 700                                 debug_object_fixup(descr->fixup_free,
 701                                                    (void *) oaddr, state);
 702                                 goto repeat;
 703                         default:
 704                                 hlist_del(&obj->node);
 705                                 hlist_add_head(&obj->node, &freelist);
 706                                 break;
 707                         }
 708                 }
 709                 raw_spin_unlock_irqrestore(&db->lock, flags);
 710
 711                 /* Now free them */
 712                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 713                         hlist_del(&obj->node);
 714                         free_object(obj);
 715                 }
 716
 717                 if (cnt > debug_objects_maxchain)
 718                         debug_objects_maxchain = cnt;
 719         }
 720 }
 721
 722 void debug_check_no_obj_freed(const void *address, unsigned long size)
 723 {
 724         if (debug_objects_enabled)
 725                 __debug_check_no_obj_freed(address, size);
 726 }
 727 #endif
 728
 729 #ifdef CONFIG_DEBUG_FS
 730
 731 static int debug_stats_show(struct seq_file *m, void *v)
 732 {
 733         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 734         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 735         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 736         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 737         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 738         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 739         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 740         return 0;
 741 }
 742
 743 static int debug_stats_open(struct inode *inode, struct file *filp)
 744 {
 745         return single_open(filp, debug_stats_show, NULL);
 746 }
 747
 748 static const struct file_operations debug_stats_fops = {
 749         .open           = debug_stats_open,
 750         .read           = seq_read,
 751         .llseek         = seq_lseek,
 752         .release        = single_release,
 753 };
 754
 755 static int __init debug_objects_init_debugfs(void)
 756 {
 757         struct dentry *dbgdir, *dbgstats;
 758
 759         if (!debug_objects_enabled)
 760                 return 0;
 761
 762         dbgdir = debugfs_create_dir("debug_objects", NULL);
 763         if (!dbgdir)
 764                 return -ENOMEM;
 765
 766         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 767                                        &debug_stats_fops);
 768         if (!dbgstats)
 769                 goto err;
 770
 771         return 0;
 772
 773 err:
 774         debugfs_remove(dbgdir);
 775
 776         return -ENOMEM;
 777 }
 778 __initcall(debug_objects_init_debugfs);
 779
 780 #else
 781 static inline void debug_objects_init_debugfs(void) { }
 782 #endif
 783
 784 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 785
 786 /* Random data structure for the self test */
 787 struct self_test {
 788         unsigned long   dummy1[6];
 789         int             static_init;
 790         unsigned long   dummy2[3];
 791 };
 792
 793 static __initdata struct debug_obj_descr descr_type_test;
 794
 795 /*
 796  * fixup_init is called when:
 797  * - an active object is initialized
 798  */
 799 static int __init fixup_init(void *addr, enum debug_obj_state state)
 800 {
 801         struct self_test *obj = addr;
 802
 803         switch (state) {
 804         case ODEBUG_STATE_ACTIVE:
 805                 debug_object_deactivate(obj, &descr_type_test);
 806                 debug_object_init(obj, &descr_type_test);
 807                 return 1;
 808         default:
 809                 return 0;
 810         }
 811 }
 812
 813 /*
 814  * fixup_activate is called when:
 815  * - an active object is activated
 816  * - an unknown object is activated (might be a statically initialized object)
 817  */
 818 static int __init fixup_activate(void *addr, enum debug_obj_state state)
 819 {
 820         struct self_test *obj = addr;
 821
 822         switch (state) {
 823         case ODEBUG_STATE_NOTAVAILABLE:
 824                 if (obj->static_init == 1) {
 825                         debug_object_init(obj, &descr_type_test);
 826                         debug_object_activate(obj, &descr_type_test);
 827                         return 0;
 828                 }
 829                 return 1;
 830
 831         case ODEBUG_STATE_ACTIVE:
 832                 debug_object_deactivate(obj, &descr_type_test);
 833                 debug_object_activate(obj, &descr_type_test);
 834                 return 1;
 835
 836         default:
 837                 return 0;
 838         }
 839 }
 840
 841 /*
 842  * fixup_destroy is called when:
 843  * - an active object is destroyed
 844  */
 845 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
 846 {
 847         struct self_test *obj = addr;
 848
 849         switch (state) {
 850         case ODEBUG_STATE_ACTIVE:
 851                 debug_object_deactivate(obj, &descr_type_test);
 852                 debug_object_destroy(obj, &descr_type_test);
 853                 return 1;
 854         default:
 855                 return 0;
 856         }
 857 }
 858
 859 /*
 860  * fixup_free is called when:
 861  * - an active object is freed
 862  */
 863 static int __init fixup_free(void *addr, enum debug_obj_state state)
 864 {
 865         struct self_test *obj = addr;
 866
 867         switch (state) {
 868         case ODEBUG_STATE_ACTIVE:
 869                 debug_object_deactivate(obj, &descr_type_test);
 870                 debug_object_free(obj, &descr_type_test);
 871                 return 1;
 872         default:
 873                 return 0;
 874         }
 875 }
 876
 877 static int __init
 878 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 879 {
 880         struct debug_bucket *db;
 881         struct debug_obj *obj;
 882         unsigned long flags;
 883         int res = -EINVAL;
 884
 885         db = get_bucket((unsigned long) addr);
 886
 887         raw_spin_lock_irqsave(&db->lock, flags);
 888
 889         obj = lookup_object(addr, db);
 890         if (!obj && state != ODEBUG_STATE_NONE) {
 891                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 892                 goto out;
 893         }
 894         if (obj && obj->state != state) {
 895                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 896                        obj->state, state);
 897                 goto out;
 898         }
 899         if (fixups != debug_objects_fixups) {
 900                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 901                        fixups, debug_objects_fixups);
 902                 goto out;
 903         }
 904         if (warnings != debug_objects_warnings) {
 905                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 906                        warnings, debug_objects_warnings);
 907                 goto out;
 908         }
 909         res = 0;
 910 out:
 911         raw_spin_unlock_irqrestore(&db->lock, flags);
 912         if (res)
 913                 debug_objects_enabled = 0;
 914         return res;
 915 }
 916
 917 static __initdata struct debug_obj_descr descr_type_test = {
 918         .name                   = "selftest",
 919         .fixup_init             = fixup_init,
 920         .fixup_activate         = fixup_activate,
 921         .fixup_destroy          = fixup_destroy,
 922         .fixup_free             = fixup_free,
 923 };
 924
 925 static __initdata struct self_test obj = { .static_init = 0 };
 926
 927 static void __init debug_objects_selftest(void)
 928 {
 929         int fixups, oldfixups, warnings, oldwarnings;
 930         unsigned long flags;
 931
 932         local_irq_save(flags);
 933
 934         fixups = oldfixups = debug_objects_fixups;
 935         warnings = oldwarnings = debug_objects_warnings;
 936         descr_test = &descr_type_test;
 937
 938         debug_object_init(&obj, &descr_type_test);
 939         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 940                 goto out;
 941         debug_object_activate(&obj, &descr_type_test);
 942         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 943                 goto out;
 944         debug_object_activate(&obj, &descr_type_test);
 945         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 946                 goto out;
 947         debug_object_deactivate(&obj, &descr_type_test);
 948         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 949                 goto out;
 950         debug_object_destroy(&obj, &descr_type_test);
 951         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 952                 goto out;
 953         debug_object_init(&obj, &descr_type_test);
 954         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 955                 goto out;
 956         debug_object_activate(&obj, &descr_type_test);
 957         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 958                 goto out;
 959         debug_object_deactivate(&obj, &descr_type_test);
 960         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 961                 goto out;
 962         debug_object_free(&obj, &descr_type_test);
 963         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 964                 goto out;
 965
 966         obj.static_init = 1;
 967         debug_object_activate(&obj, &descr_type_test);
 968         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 969                 goto out;
 970         debug_object_init(&obj, &descr_type_test);
 971         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
 972                 goto out;
 973         debug_object_free(&obj, &descr_type_test);
 974         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 975                 goto out;
 976
 977 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 978         debug_object_init(&obj, &descr_type_test);
 979         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 980                 goto out;
 981         debug_object_activate(&obj, &descr_type_test);
 982         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 983                 goto out;
 984         __debug_check_no_obj_freed(&obj, sizeof(obj));
 985         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
 986                 goto out;
 987 #endif
 988         printk(KERN_INFO "ODEBUG: selftest passed\n");
 989
 990 out:
 991         debug_objects_fixups = oldfixups;
 992         debug_objects_warnings = oldwarnings;
 993         descr_test = NULL;
 994
 995         local_irq_restore(flags);
 996 }
 997 #else
 998 static inline void debug_objects_selftest(void) { }
 999 #endif
1000
1001 /*
1002  * Called during early boot to initialize the hash buckets and link
1003  * the static object pool objects into the poll list. After this call
1004  * the object tracker is fully operational.
1005  */
1006 void __init debug_objects_early_init(void)
1007 {
1008         int i;
1009
1010         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1011                 raw_spin_lock_init(&obj_hash[i].lock);
1012
1013         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1014                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1015 }
1016
1017 /*
1018  * Convert the statically allocated objects to dynamic ones:
1019  */
1020 static int __init debug_objects_replace_static_objects(void)
1021 {
1022         struct debug_bucket *db = obj_hash;
1023         struct hlist_node *tmp;
1024         struct debug_obj *obj, *new;
1025         HLIST_HEAD(objects);
1026         int i, cnt = 0;
1027
1028         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1029                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1030                 if (!obj)
1031                         goto free;
1032                 hlist_add_head(&obj->node, &objects);
1033         }
1034
1035         /*
1036          * When debug_objects_mem_init() is called we know that only
1037          * one CPU is up, so disabling interrupts is enough
1038          * protection. This avoids the lockdep hell of lock ordering.
1039          */
1040         local_irq_disable();
1041
1042         /* Remove the statically allocated objects from the pool */
1043         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1044                 hlist_del(&obj->node);
1045         /* Move the allocated objects to the pool */
1046         hlist_move_list(&objects, &obj_pool);
1047
1048         /* Replace the active object references */
1049         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1050                 hlist_move_list(&db->list, &objects);
1051
1052                 hlist_for_each_entry(obj, &objects, node) {
1053                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1054                         hlist_del(&new->node);
1055                         /* copy object data */
1056                         *new = *obj;
1057                         hlist_add_head(&new->node, &db->list);
1058                         cnt++;
1059                 }
1060         }
1061         local_irq_enable();
1062
1063         printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
1064                obj_pool_used);
1065         return 0;
1066 free:
1067         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1068                 hlist_del(&obj->node);
1069                 kmem_cache_free(obj_cache, obj);
1070         }
1071         return -ENOMEM;
1072 }
1073
1074 /*
1075  * Called after the kmem_caches are functional to setup a dedicated
1076  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1077  * prevents that the debug code is called on kmem_cache_free() for the
1078  * debug tracker objects to avoid recursive calls.
1079  */
1080 void __init debug_objects_mem_init(void)
1081 {
1082         if (!debug_objects_enabled)
1083                 return;
1084
1085         obj_cache = kmem_cache_create("debug_objects_cache",
1086                                       sizeof (struct debug_obj), 0,
1087                                       SLAB_DEBUG_OBJECTS, NULL);
1088
1089         if (!obj_cache || debug_objects_replace_static_objects()) {
1090                 debug_objects_enabled = 0;
1091                 if (obj_cache)
1092                         kmem_cache_destroy(obj_cache);
1093                 printk(KERN_WARNING "ODEBUG: out of memory.\n");
1094         } else
1095                 debug_objects_selftest();
1096 }