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
  11 #define pr_fmt(fmt) "ODEBUG: " fmt
  12
  13 #include <linux/debugobjects.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/sched.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/debugfs.h>
  18 #include <linux/slab.h>
  19 #include <linux/hash.h>
  20
  21 #define ODEBUG_HASH_BITS        14
  22 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  23
  24 #define ODEBUG_POOL_SIZE        1024
  25 #define ODEBUG_POOL_MIN_LEVEL   256
  26
  27 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  28 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  29 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  30
  31 struct debug_bucket {
  32         struct hlist_head       list;
  33         raw_spinlock_t          lock;
  34 };
  35
  36 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  37
  38 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  39
  40 static DEFINE_RAW_SPINLOCK(pool_lock);
  41
  42 static HLIST_HEAD(obj_pool);
  43
  44 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  45 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  46 static int                      obj_pool_used;
  47 static int                      obj_pool_max_used;
  48 static struct kmem_cache        *obj_cache;
  49
  50 static int                      debug_objects_maxchain __read_mostly;
  51 static int                      debug_objects_fixups __read_mostly;
  52 static int                      debug_objects_warnings __read_mostly;
  53 static int                      debug_objects_enabled __read_mostly
  54                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  55
  56 static struct debug_obj_descr   *descr_test  __read_mostly;
  57
  58 /*
  59  * Track numbers of kmem_cache_alloc and kmem_cache_free done.
  60  */
  61 static int                      debug_objects_alloc;
  62 static int                      debug_objects_freed;
  63
  64 static void free_obj_work(struct work_struct *work);
  65 static DECLARE_WORK(debug_obj_work, free_obj_work);
  66
  67 static int __init enable_object_debug(char *str)
  68 {
  69         debug_objects_enabled = 1;
  70         return 0;
  71 }
  72
  73 static int __init disable_object_debug(char *str)
  74 {
  75         debug_objects_enabled = 0;
  76         return 0;
  77 }
  78
  79 early_param("debug_objects", enable_object_debug);
  80 early_param("no_debug_objects", disable_object_debug);
  81
  82 static const char *obj_states[ODEBUG_STATE_MAX] = {
  83         [ODEBUG_STATE_NONE]             = "none",
  84         [ODEBUG_STATE_INIT]             = "initialized",
  85         [ODEBUG_STATE_INACTIVE]         = "inactive",
  86         [ODEBUG_STATE_ACTIVE]           = "active",
  87         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  88         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  89 };
  90
  91 static void fill_pool(void)
  92 {
  93         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  94         struct debug_obj *new;
  95         unsigned long flags;
  96
  97         if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
  98                 return;
  99
 100         if (unlikely(!obj_cache))
 101                 return;
 102
 103         while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
 104
 105                 new = kmem_cache_zalloc(obj_cache, gfp);
 106                 if (!new)
 107                         return;
 108
 109                 raw_spin_lock_irqsave(&pool_lock, flags);
 110                 hlist_add_head(&new->node, &obj_pool);
 111                 debug_objects_alloc++;
 112                 obj_pool_free++;
 113                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 114         }
 115 }
 116
 117 /*
 118  * Lookup an object in the hash bucket.
 119  */
 120 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 121 {
 122         struct debug_obj *obj;
 123         int cnt = 0;
 124
 125         hlist_for_each_entry(obj, &b->list, node) {
 126                 cnt++;
 127                 if (obj->object == addr)
 128                         return obj;
 129         }
 130         if (cnt > debug_objects_maxchain)
 131                 debug_objects_maxchain = cnt;
 132
 133         return NULL;
 134 }
 135
 136 /*
 137  * Allocate a new object. If the pool is empty, switch off the debugger.
 138  * Must be called with interrupts disabled.
 139  */
 140 static struct debug_obj *
 141 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 142 {
 143         struct debug_obj *obj = NULL;
 144
 145         raw_spin_lock(&pool_lock);
 146         if (obj_pool.first) {
 147                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 148
 149                 obj->object = addr;
 150                 obj->descr  = descr;
 151                 obj->state  = ODEBUG_STATE_NONE;
 152                 obj->astate = 0;
 153                 hlist_del(&obj->node);
 154
 155                 hlist_add_head(&obj->node, &b->list);
 156
 157                 obj_pool_used++;
 158                 if (obj_pool_used > obj_pool_max_used)
 159                         obj_pool_max_used = obj_pool_used;
 160
 161                 obj_pool_free--;
 162                 if (obj_pool_free < obj_pool_min_free)
 163                         obj_pool_min_free = obj_pool_free;
 164         }
 165         raw_spin_unlock(&pool_lock);
 166
 167         return obj;
 168 }
 169
 170 /*
 171  * workqueue function to free objects.
 172  */
 173 static void free_obj_work(struct work_struct *work)
 174 {
 175         struct debug_obj *obj;
 176         unsigned long flags;
 177
 178         raw_spin_lock_irqsave(&pool_lock, flags);
 179         while (obj_pool_free > ODEBUG_POOL_SIZE) {
 180                 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
 181                 hlist_del(&obj->node);
 182                 obj_pool_free--;
 183                 debug_objects_freed++;
 184                 /*
 185                  * We release pool_lock across kmem_cache_free() to
 186                  * avoid contention on pool_lock.
 187                  */
 188                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 189                 kmem_cache_free(obj_cache, obj);
 190                 raw_spin_lock_irqsave(&pool_lock, flags);
 191         }
 192         raw_spin_unlock_irqrestore(&pool_lock, flags);
 193 }
 194
 195 /*
 196  * Put the object back into the pool and schedule work to free objects
 197  * if necessary.
 198  */
 199 static void free_object(struct debug_obj *obj)
 200 {
 201         unsigned long flags;
 202         int sched = 0;
 203
 204         raw_spin_lock_irqsave(&pool_lock, flags);
 205         /*
 206          * schedule work when the pool is filled and the cache is
 207          * initialized:
 208          */
 209         if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
 210                 sched = 1;
 211         hlist_add_head(&obj->node, &obj_pool);
 212         obj_pool_free++;
 213         obj_pool_used--;
 214         raw_spin_unlock_irqrestore(&pool_lock, flags);
 215         if (sched)
 216                 schedule_work(&debug_obj_work);
 217 }
 218
 219 /*
 220  * We run out of memory. That means we probably have tons of objects
 221  * allocated.
 222  */
 223 static void debug_objects_oom(void)
 224 {
 225         struct debug_bucket *db = obj_hash;
 226         struct hlist_node *tmp;
 227         HLIST_HEAD(freelist);
 228         struct debug_obj *obj;
 229         unsigned long flags;
 230         int i;
 231
 232         pr_warn("Out of memory. ODEBUG disabled\n");
 233
 234         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 235                 raw_spin_lock_irqsave(&db->lock, flags);
 236                 hlist_move_list(&db->list, &freelist);
 237                 raw_spin_unlock_irqrestore(&db->lock, flags);
 238
 239                 /* Now free them */
 240                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 241                         hlist_del(&obj->node);
 242                         free_object(obj);
 243                 }
 244         }
 245 }
 246
 247 /*
 248  * We use the pfn of the address for the hash. That way we can check
 249  * for freed objects simply by checking the affected bucket.
 250  */
 251 static struct debug_bucket *get_bucket(unsigned long addr)
 252 {
 253         unsigned long hash;
 254
 255         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 256         return &obj_hash[hash];
 257 }
 258
 259 static void debug_print_object(struct debug_obj *obj, char *msg)
 260 {
 261         struct debug_obj_descr *descr = obj->descr;
 262         static int limit;
 263
 264         if (limit < 5 && descr != descr_test) {
 265                 void *hint = descr->debug_hint ?
 266                         descr->debug_hint(obj->object) : NULL;
 267                 limit++;
 268                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 269                                  "object type: %s hint: %pS\n",
 270                         msg, obj_states[obj->state], obj->astate,
 271                         descr->name, hint);
 272         }
 273         debug_objects_warnings++;
 274 }
 275
 276 /*
 277  * Try to repair the damage, so we have a better chance to get useful
 278  * debug output.
 279  */
 280 static bool
 281 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 282                    void * addr, enum debug_obj_state state)
 283 {
 284         if (fixup && fixup(addr, state)) {
 285                 debug_objects_fixups++;
 286                 return true;
 287         }
 288         return false;
 289 }
 290
 291 static void debug_object_is_on_stack(void *addr, int onstack)
 292 {
 293         int is_on_stack;
 294         static int limit;
 295
 296         if (limit > 4)
 297                 return;
 298
 299         is_on_stack = object_is_on_stack(addr);
 300         if (is_on_stack == onstack)
 301                 return;
 302
 303         limit++;
 304         if (is_on_stack)
 305                 pr_warn("object is on stack, but not annotated\n");
 306         else
 307                 pr_warn("object is not on stack, but annotated\n");
 308         WARN_ON(1);
 309 }
 310
 311 static void
 312 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 313 {
 314         enum debug_obj_state state;
 315         struct debug_bucket *db;
 316         struct debug_obj *obj;
 317         unsigned long flags;
 318
 319         fill_pool();
 320
 321         db = get_bucket((unsigned long) addr);
 322
 323         raw_spin_lock_irqsave(&db->lock, flags);
 324
 325         obj = lookup_object(addr, db);
 326         if (!obj) {
 327                 obj = alloc_object(addr, db, descr);
 328                 if (!obj) {
 329                         debug_objects_enabled = 0;
 330                         raw_spin_unlock_irqrestore(&db->lock, flags);
 331                         debug_objects_oom();
 332                         return;
 333                 }
 334                 debug_object_is_on_stack(addr, onstack);
 335         }
 336
 337         switch (obj->state) {
 338         case ODEBUG_STATE_NONE:
 339         case ODEBUG_STATE_INIT:
 340         case ODEBUG_STATE_INACTIVE:
 341                 obj->state = ODEBUG_STATE_INIT;
 342                 break;
 343
 344         case ODEBUG_STATE_ACTIVE:
 345                 debug_print_object(obj, "init");
 346                 state = obj->state;
 347                 raw_spin_unlock_irqrestore(&db->lock, flags);
 348                 debug_object_fixup(descr->fixup_init, addr, state);
 349                 return;
 350
 351         case ODEBUG_STATE_DESTROYED:
 352                 debug_print_object(obj, "init");
 353                 break;
 354         default:
 355                 break;
 356         }
 357
 358         raw_spin_unlock_irqrestore(&db->lock, flags);
 359 }
 360
 361 /**
 362  * debug_object_init - debug checks when an object is initialized
 363  * @addr:       address of the object
 364  * @descr:      pointer to an object specific debug description structure
 365  */
 366 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 367 {
 368         if (!debug_objects_enabled)
 369                 return;
 370
 371         __debug_object_init(addr, descr, 0);
 372 }
 373 EXPORT_SYMBOL_GPL(debug_object_init);
 374
 375 /**
 376  * debug_object_init_on_stack - debug checks when an object on stack is
 377  *                              initialized
 378  * @addr:       address of the object
 379  * @descr:      pointer to an object specific debug description structure
 380  */
 381 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 382 {
 383         if (!debug_objects_enabled)
 384                 return;
 385
 386         __debug_object_init(addr, descr, 1);
 387 }
 388 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 389
 390 /**
 391  * debug_object_activate - debug checks when an object is activated
 392  * @addr:       address of the object
 393  * @descr:      pointer to an object specific debug description structure
 394  * Returns 0 for success, -EINVAL for check failed.
 395  */
 396 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 397 {
 398         enum debug_obj_state state;
 399         struct debug_bucket *db;
 400         struct debug_obj *obj;
 401         unsigned long flags;
 402         int ret;
 403         struct debug_obj o = { .object = addr,
 404                                .state = ODEBUG_STATE_NOTAVAILABLE,
 405                                .descr = descr };
 406
 407         if (!debug_objects_enabled)
 408                 return 0;
 409
 410         db = get_bucket((unsigned long) addr);
 411
 412         raw_spin_lock_irqsave(&db->lock, flags);
 413
 414         obj = lookup_object(addr, db);
 415         if (obj) {
 416                 switch (obj->state) {
 417                 case ODEBUG_STATE_INIT:
 418                 case ODEBUG_STATE_INACTIVE:
 419                         obj->state = ODEBUG_STATE_ACTIVE;
 420                         ret = 0;
 421                         break;
 422
 423                 case ODEBUG_STATE_ACTIVE:
 424                         debug_print_object(obj, "activate");
 425                         state = obj->state;
 426                         raw_spin_unlock_irqrestore(&db->lock, flags);
 427                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 428                         return ret ? 0 : -EINVAL;
 429
 430                 case ODEBUG_STATE_DESTROYED:
 431                         debug_print_object(obj, "activate");
 432                         ret = -EINVAL;
 433                         break;
 434                 default:
 435                         ret = 0;
 436                         break;
 437                 }
 438                 raw_spin_unlock_irqrestore(&db->lock, flags);
 439                 return ret;
 440         }
 441
 442         raw_spin_unlock_irqrestore(&db->lock, flags);
 443         /*
 444          * We are here when a static object is activated. We
 445          * let the type specific code confirm whether this is
 446          * true or not. if true, we just make sure that the
 447          * static object is tracked in the object tracker. If
 448          * not, this must be a bug, so we try to fix it up.
 449          */
 450         if (descr->is_static_object && descr->is_static_object(addr)) {
 451                 /* track this static object */
 452                 debug_object_init(addr, descr);
 453                 debug_object_activate(addr, descr);
 454         } else {
 455                 debug_print_object(&o, "activate");
 456                 ret = debug_object_fixup(descr->fixup_activate, addr,
 457                                         ODEBUG_STATE_NOTAVAILABLE);
 458                 return ret ? 0 : -EINVAL;
 459         }
 460         return 0;
 461 }
 462 EXPORT_SYMBOL_GPL(debug_object_activate);
 463
 464 /**
 465  * debug_object_deactivate - debug checks when an object is deactivated
 466  * @addr:       address of the object
 467  * @descr:      pointer to an object specific debug description structure
 468  */
 469 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 470 {
 471         struct debug_bucket *db;
 472         struct debug_obj *obj;
 473         unsigned long flags;
 474
 475         if (!debug_objects_enabled)
 476                 return;
 477
 478         db = get_bucket((unsigned long) addr);
 479
 480         raw_spin_lock_irqsave(&db->lock, flags);
 481
 482         obj = lookup_object(addr, db);
 483         if (obj) {
 484                 switch (obj->state) {
 485                 case ODEBUG_STATE_INIT:
 486                 case ODEBUG_STATE_INACTIVE:
 487                 case ODEBUG_STATE_ACTIVE:
 488                         if (!obj->astate)
 489                                 obj->state = ODEBUG_STATE_INACTIVE;
 490                         else
 491                                 debug_print_object(obj, "deactivate");
 492                         break;
 493
 494                 case ODEBUG_STATE_DESTROYED:
 495                         debug_print_object(obj, "deactivate");
 496                         break;
 497                 default:
 498                         break;
 499                 }
 500         } else {
 501                 struct debug_obj o = { .object = addr,
 502                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 503                                        .descr = descr };
 504
 505                 debug_print_object(&o, "deactivate");
 506         }
 507
 508         raw_spin_unlock_irqrestore(&db->lock, flags);
 509 }
 510 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 511
 512 /**
 513  * debug_object_destroy - debug checks when an object is destroyed
 514  * @addr:       address of the object
 515  * @descr:      pointer to an object specific debug description structure
 516  */
 517 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 518 {
 519         enum debug_obj_state state;
 520         struct debug_bucket *db;
 521         struct debug_obj *obj;
 522         unsigned long flags;
 523
 524         if (!debug_objects_enabled)
 525                 return;
 526
 527         db = get_bucket((unsigned long) addr);
 528
 529         raw_spin_lock_irqsave(&db->lock, flags);
 530
 531         obj = lookup_object(addr, db);
 532         if (!obj)
 533                 goto out_unlock;
 534
 535         switch (obj->state) {
 536         case ODEBUG_STATE_NONE:
 537         case ODEBUG_STATE_INIT:
 538         case ODEBUG_STATE_INACTIVE:
 539                 obj->state = ODEBUG_STATE_DESTROYED;
 540                 break;
 541         case ODEBUG_STATE_ACTIVE:
 542                 debug_print_object(obj, "destroy");
 543                 state = obj->state;
 544                 raw_spin_unlock_irqrestore(&db->lock, flags);
 545                 debug_object_fixup(descr->fixup_destroy, addr, state);
 546                 return;
 547
 548         case ODEBUG_STATE_DESTROYED:
 549                 debug_print_object(obj, "destroy");
 550                 break;
 551         default:
 552                 break;
 553         }
 554 out_unlock:
 555         raw_spin_unlock_irqrestore(&db->lock, flags);
 556 }
 557 EXPORT_SYMBOL_GPL(debug_object_destroy);
 558
 559 /**
 560  * debug_object_free - debug checks when an object is freed
 561  * @addr:       address of the object
 562  * @descr:      pointer to an object specific debug description structure
 563  */
 564 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 565 {
 566         enum debug_obj_state state;
 567         struct debug_bucket *db;
 568         struct debug_obj *obj;
 569         unsigned long flags;
 570
 571         if (!debug_objects_enabled)
 572                 return;
 573
 574         db = get_bucket((unsigned long) addr);
 575
 576         raw_spin_lock_irqsave(&db->lock, flags);
 577
 578         obj = lookup_object(addr, db);
 579         if (!obj)
 580                 goto out_unlock;
 581
 582         switch (obj->state) {
 583         case ODEBUG_STATE_ACTIVE:
 584                 debug_print_object(obj, "free");
 585                 state = obj->state;
 586                 raw_spin_unlock_irqrestore(&db->lock, flags);
 587                 debug_object_fixup(descr->fixup_free, addr, state);
 588                 return;
 589         default:
 590                 hlist_del(&obj->node);
 591                 raw_spin_unlock_irqrestore(&db->lock, flags);
 592                 free_object(obj);
 593                 return;
 594         }
 595 out_unlock:
 596         raw_spin_unlock_irqrestore(&db->lock, flags);
 597 }
 598 EXPORT_SYMBOL_GPL(debug_object_free);
 599
 600 /**
 601  * debug_object_assert_init - debug checks when object should be init-ed
 602  * @addr:       address of the object
 603  * @descr:      pointer to an object specific debug description structure
 604  */
 605 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 606 {
 607         struct debug_bucket *db;
 608         struct debug_obj *obj;
 609         unsigned long flags;
 610
 611         if (!debug_objects_enabled)
 612                 return;
 613
 614         db = get_bucket((unsigned long) addr);
 615
 616         raw_spin_lock_irqsave(&db->lock, flags);
 617
 618         obj = lookup_object(addr, db);
 619         if (!obj) {
 620                 struct debug_obj o = { .object = addr,
 621                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 622                                        .descr = descr };
 623
 624                 raw_spin_unlock_irqrestore(&db->lock, flags);
 625                 /*
 626                  * Maybe the object is static, and we let the type specific
 627                  * code confirm. Track this static object if true, else invoke
 628                  * fixup.
 629                  */
 630                 if (descr->is_static_object && descr->is_static_object(addr)) {
 631                         /* Track this static object */
 632                         debug_object_init(addr, descr);
 633                 } else {
 634                         debug_print_object(&o, "assert_init");
 635                         debug_object_fixup(descr->fixup_assert_init, addr,
 636                                            ODEBUG_STATE_NOTAVAILABLE);
 637                 }
 638                 return;
 639         }
 640
 641         raw_spin_unlock_irqrestore(&db->lock, flags);
 642 }
 643 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 644
 645 /**
 646  * debug_object_active_state - debug checks object usage state machine
 647  * @addr:       address of the object
 648  * @descr:      pointer to an object specific debug description structure
 649  * @expect:     expected state
 650  * @next:       state to move to if expected state is found
 651  */
 652 void
 653 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 654                           unsigned int expect, unsigned int next)
 655 {
 656         struct debug_bucket *db;
 657         struct debug_obj *obj;
 658         unsigned long flags;
 659
 660         if (!debug_objects_enabled)
 661                 return;
 662
 663         db = get_bucket((unsigned long) addr);
 664
 665         raw_spin_lock_irqsave(&db->lock, flags);
 666
 667         obj = lookup_object(addr, db);
 668         if (obj) {
 669                 switch (obj->state) {
 670                 case ODEBUG_STATE_ACTIVE:
 671                         if (obj->astate == expect)
 672                                 obj->astate = next;
 673                         else
 674                                 debug_print_object(obj, "active_state");
 675                         break;
 676
 677                 default:
 678                         debug_print_object(obj, "active_state");
 679                         break;
 680                 }
 681         } else {
 682                 struct debug_obj o = { .object = addr,
 683                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 684                                        .descr = descr };
 685
 686                 debug_print_object(&o, "active_state");
 687         }
 688
 689         raw_spin_unlock_irqrestore(&db->lock, flags);
 690 }
 691 EXPORT_SYMBOL_GPL(debug_object_active_state);
 692
 693 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 694 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 695 {
 696         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 697         struct hlist_node *tmp;
 698         HLIST_HEAD(freelist);
 699         struct debug_obj_descr *descr;
 700         enum debug_obj_state state;
 701         struct debug_bucket *db;
 702         struct debug_obj *obj;
 703         int cnt;
 704
 705         saddr = (unsigned long) address;
 706         eaddr = saddr + size;
 707         paddr = saddr & ODEBUG_CHUNK_MASK;
 708         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 709         chunks >>= ODEBUG_CHUNK_SHIFT;
 710
 711         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 712                 db = get_bucket(paddr);
 713
 714 repeat:
 715                 cnt = 0;
 716                 raw_spin_lock_irqsave(&db->lock, flags);
 717                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 718                         cnt++;
 719                         oaddr = (unsigned long) obj->object;
 720                         if (oaddr < saddr || oaddr >= eaddr)
 721                                 continue;
 722
 723                         switch (obj->state) {
 724                         case ODEBUG_STATE_ACTIVE:
 725                                 debug_print_object(obj, "free");
 726                                 descr = obj->descr;
 727                                 state = obj->state;
 728                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 729                                 debug_object_fixup(descr->fixup_free,
 730                                                    (void *) oaddr, state);
 731                                 goto repeat;
 732                         default:
 733                                 hlist_del(&obj->node);
 734                                 hlist_add_head(&obj->node, &freelist);
 735                                 break;
 736                         }
 737                 }
 738                 raw_spin_unlock_irqrestore(&db->lock, flags);
 739
 740                 /* Now free them */
 741                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 742                         hlist_del(&obj->node);
 743                         free_object(obj);
 744                 }
 745
 746                 if (cnt > debug_objects_maxchain)
 747                         debug_objects_maxchain = cnt;
 748         }
 749 }
 750
 751 void debug_check_no_obj_freed(const void *address, unsigned long size)
 752 {
 753         if (debug_objects_enabled)
 754                 __debug_check_no_obj_freed(address, size);
 755 }
 756 #endif
 757
 758 #ifdef CONFIG_DEBUG_FS
 759
 760 static int debug_stats_show(struct seq_file *m, void *v)
 761 {
 762         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 763         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 764         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 765         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 766         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 767         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 768         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 769         seq_printf(m, "objects_alloc :%d\n", debug_objects_alloc);
 770         seq_printf(m, "objects_freed :%d\n", debug_objects_freed);
 771         return 0;
 772 }
 773
 774 static int debug_stats_open(struct inode *inode, struct file *filp)
 775 {
 776         return single_open(filp, debug_stats_show, NULL);
 777 }
 778
 779 static const struct file_operations debug_stats_fops = {
 780         .open           = debug_stats_open,
 781         .read           = seq_read,
 782         .llseek         = seq_lseek,
 783         .release        = single_release,
 784 };
 785
 786 static int __init debug_objects_init_debugfs(void)
 787 {
 788         struct dentry *dbgdir, *dbgstats;
 789
 790         if (!debug_objects_enabled)
 791                 return 0;
 792
 793         dbgdir = debugfs_create_dir("debug_objects", NULL);
 794         if (!dbgdir)
 795                 return -ENOMEM;
 796
 797         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 798                                        &debug_stats_fops);
 799         if (!dbgstats)
 800                 goto err;
 801
 802         return 0;
 803
 804 err:
 805         debugfs_remove(dbgdir);
 806
 807         return -ENOMEM;
 808 }
 809 __initcall(debug_objects_init_debugfs);
 810
 811 #else
 812 static inline void debug_objects_init_debugfs(void) { }
 813 #endif
 814
 815 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 816
 817 /* Random data structure for the self test */
 818 struct self_test {
 819         unsigned long   dummy1[6];
 820         int             static_init;
 821         unsigned long   dummy2[3];
 822 };
 823
 824 static __initdata struct debug_obj_descr descr_type_test;
 825
 826 static bool __init is_static_object(void *addr)
 827 {
 828         struct self_test *obj = addr;
 829
 830         return obj->static_init;
 831 }
 832
 833 /*
 834  * fixup_init is called when:
 835  * - an active object is initialized
 836  */
 837 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 838 {
 839         struct self_test *obj = addr;
 840
 841         switch (state) {
 842         case ODEBUG_STATE_ACTIVE:
 843                 debug_object_deactivate(obj, &descr_type_test);
 844                 debug_object_init(obj, &descr_type_test);
 845                 return true;
 846         default:
 847                 return false;
 848         }
 849 }
 850
 851 /*
 852  * fixup_activate is called when:
 853  * - an active object is activated
 854  * - an unknown non-static object is activated
 855  */
 856 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 857 {
 858         struct self_test *obj = addr;
 859
 860         switch (state) {
 861         case ODEBUG_STATE_NOTAVAILABLE:
 862                 return true;
 863         case ODEBUG_STATE_ACTIVE:
 864                 debug_object_deactivate(obj, &descr_type_test);
 865                 debug_object_activate(obj, &descr_type_test);
 866                 return true;
 867
 868         default:
 869                 return false;
 870         }
 871 }
 872
 873 /*
 874  * fixup_destroy is called when:
 875  * - an active object is destroyed
 876  */
 877 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 878 {
 879         struct self_test *obj = addr;
 880
 881         switch (state) {
 882         case ODEBUG_STATE_ACTIVE:
 883                 debug_object_deactivate(obj, &descr_type_test);
 884                 debug_object_destroy(obj, &descr_type_test);
 885                 return true;
 886         default:
 887                 return false;
 888         }
 889 }
 890
 891 /*
 892  * fixup_free is called when:
 893  * - an active object is freed
 894  */
 895 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 896 {
 897         struct self_test *obj = addr;
 898
 899         switch (state) {
 900         case ODEBUG_STATE_ACTIVE:
 901                 debug_object_deactivate(obj, &descr_type_test);
 902                 debug_object_free(obj, &descr_type_test);
 903                 return true;
 904         default:
 905                 return false;
 906         }
 907 }
 908
 909 static int __init
 910 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 911 {
 912         struct debug_bucket *db;
 913         struct debug_obj *obj;
 914         unsigned long flags;
 915         int res = -EINVAL;
 916
 917         db = get_bucket((unsigned long) addr);
 918
 919         raw_spin_lock_irqsave(&db->lock, flags);
 920
 921         obj = lookup_object(addr, db);
 922         if (!obj && state != ODEBUG_STATE_NONE) {
 923                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 924                 goto out;
 925         }
 926         if (obj && obj->state != state) {
 927                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 928                        obj->state, state);
 929                 goto out;
 930         }
 931         if (fixups != debug_objects_fixups) {
 932                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 933                        fixups, debug_objects_fixups);
 934                 goto out;
 935         }
 936         if (warnings != debug_objects_warnings) {
 937                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 938                        warnings, debug_objects_warnings);
 939                 goto out;
 940         }
 941         res = 0;
 942 out:
 943         raw_spin_unlock_irqrestore(&db->lock, flags);
 944         if (res)
 945                 debug_objects_enabled = 0;
 946         return res;
 947 }
 948
 949 static __initdata struct debug_obj_descr descr_type_test = {
 950         .name                   = "selftest",
 951         .is_static_object       = is_static_object,
 952         .fixup_init             = fixup_init,
 953         .fixup_activate         = fixup_activate,
 954         .fixup_destroy          = fixup_destroy,
 955         .fixup_free             = fixup_free,
 956 };
 957
 958 static __initdata struct self_test obj = { .static_init = 0 };
 959
 960 static void __init debug_objects_selftest(void)
 961 {
 962         int fixups, oldfixups, warnings, oldwarnings;
 963         unsigned long flags;
 964
 965         local_irq_save(flags);
 966
 967         fixups = oldfixups = debug_objects_fixups;
 968         warnings = oldwarnings = debug_objects_warnings;
 969         descr_test = &descr_type_test;
 970
 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_object_activate(&obj, &descr_type_test);
 978         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 979                 goto out;
 980         debug_object_deactivate(&obj, &descr_type_test);
 981         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 982                 goto out;
 983         debug_object_destroy(&obj, &descr_type_test);
 984         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 985                 goto out;
 986         debug_object_init(&obj, &descr_type_test);
 987         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 988                 goto out;
 989         debug_object_activate(&obj, &descr_type_test);
 990         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 991                 goto out;
 992         debug_object_deactivate(&obj, &descr_type_test);
 993         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 994                 goto out;
 995         debug_object_free(&obj, &descr_type_test);
 996         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 997                 goto out;
 998
 999         obj.static_init = 1;
1000         debug_object_activate(&obj, &descr_type_test);
1001         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1002                 goto out;
1003         debug_object_init(&obj, &descr_type_test);
1004         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1005                 goto out;
1006         debug_object_free(&obj, &descr_type_test);
1007         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1008                 goto out;
1009
1010 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1011         debug_object_init(&obj, &descr_type_test);
1012         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1013                 goto out;
1014         debug_object_activate(&obj, &descr_type_test);
1015         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1016                 goto out;
1017         __debug_check_no_obj_freed(&obj, sizeof(obj));
1018         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1019                 goto out;
1020 #endif
1021         pr_info("selftest passed\n");
1022
1023 out:
1024         debug_objects_fixups = oldfixups;
1025         debug_objects_warnings = oldwarnings;
1026         descr_test = NULL;
1027
1028         local_irq_restore(flags);
1029 }
1030 #else
1031 static inline void debug_objects_selftest(void) { }
1032 #endif
1033
1034 /*
1035  * Called during early boot to initialize the hash buckets and link
1036  * the static object pool objects into the poll list. After this call
1037  * the object tracker is fully operational.
1038  */
1039 void __init debug_objects_early_init(void)
1040 {
1041         int i;
1042
1043         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1044                 raw_spin_lock_init(&obj_hash[i].lock);
1045
1046         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1047                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1048 }
1049
1050 /*
1051  * Convert the statically allocated objects to dynamic ones:
1052  */
1053 static int __init debug_objects_replace_static_objects(void)
1054 {
1055         struct debug_bucket *db = obj_hash;
1056         struct hlist_node *tmp;
1057         struct debug_obj *obj, *new;
1058         HLIST_HEAD(objects);
1059         int i, cnt = 0;
1060
1061         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1062                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1063                 if (!obj)
1064                         goto free;
1065                 hlist_add_head(&obj->node, &objects);
1066         }
1067
1068         /*
1069          * When debug_objects_mem_init() is called we know that only
1070          * one CPU is up, so disabling interrupts is enough
1071          * protection. This avoids the lockdep hell of lock ordering.
1072          */
1073         local_irq_disable();
1074
1075         /* Remove the statically allocated objects from the pool */
1076         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1077                 hlist_del(&obj->node);
1078         /* Move the allocated objects to the pool */
1079         hlist_move_list(&objects, &obj_pool);
1080
1081         /* Replace the active object references */
1082         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1083                 hlist_move_list(&db->list, &objects);
1084
1085                 hlist_for_each_entry(obj, &objects, node) {
1086                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1087                         hlist_del(&new->node);
1088                         /* copy object data */
1089                         *new = *obj;
1090                         hlist_add_head(&new->node, &db->list);
1091                         cnt++;
1092                 }
1093         }
1094         local_irq_enable();
1095
1096         pr_debug("%d of %d active objects replaced\n",
1097                  cnt, obj_pool_used);
1098         return 0;
1099 free:
1100         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1101                 hlist_del(&obj->node);
1102                 kmem_cache_free(obj_cache, obj);
1103         }
1104         return -ENOMEM;
1105 }
1106
1107 /*
1108  * Called after the kmem_caches are functional to setup a dedicated
1109  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1110  * prevents that the debug code is called on kmem_cache_free() for the
1111  * debug tracker objects to avoid recursive calls.
1112  */
1113 void __init debug_objects_mem_init(void)
1114 {
1115         if (!debug_objects_enabled)
1116                 return;
1117
1118         obj_cache = kmem_cache_create("debug_objects_cache",
1119                                       sizeof (struct debug_obj), 0,
1120                                       SLAB_DEBUG_OBJECTS, NULL);
1121
1122         if (!obj_cache || debug_objects_replace_static_objects()) {
1123                 debug_objects_enabled = 0;
1124                 if (obj_cache)
1125                         kmem_cache_destroy(obj_cache);
1126                 pr_warn("out of memory.\n");
1127         } else
1128                 debug_objects_selftest();
1129 }