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