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 %p is on stack %p, but NOT annotated.\n", addr,
 298                          task_stack_page(current));
 299         else
 300                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 301                          task_stack_page(current));
 302
 303         WARN_ON(1);
 304 }
 305
 306 static void
 307 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 308 {
 309         enum debug_obj_state state;
 310         struct debug_bucket *db;
 311         struct debug_obj *obj;
 312         unsigned long flags;
 313
 314         fill_pool();
 315
 316         db = get_bucket((unsigned long) addr);
 317
 318         raw_spin_lock_irqsave(&db->lock, flags);
 319
 320         obj = lookup_object(addr, db);
 321         if (!obj) {
 322                 obj = alloc_object(addr, db, descr);
 323                 if (!obj) {
 324                         debug_objects_enabled = 0;
 325                         raw_spin_unlock_irqrestore(&db->lock, flags);
 326                         debug_objects_oom();
 327                         return;
 328                 }
 329                 debug_object_is_on_stack(addr, onstack);
 330         }
 331
 332         switch (obj->state) {
 333         case ODEBUG_STATE_NONE:
 334         case ODEBUG_STATE_INIT:
 335         case ODEBUG_STATE_INACTIVE:
 336                 obj->state = ODEBUG_STATE_INIT;
 337                 break;
 338
 339         case ODEBUG_STATE_ACTIVE:
 340                 debug_print_object(obj, "init");
 341                 state = obj->state;
 342                 raw_spin_unlock_irqrestore(&db->lock, flags);
 343                 debug_object_fixup(descr->fixup_init, addr, state);
 344                 return;
 345
 346         case ODEBUG_STATE_DESTROYED:
 347                 debug_print_object(obj, "init");
 348                 break;
 349         default:
 350                 break;
 351         }
 352
 353         raw_spin_unlock_irqrestore(&db->lock, flags);
 354 }
 355
 356 /**
 357  * debug_object_init - debug checks when an object is initialized
 358  * @addr:       address of the object
 359  * @descr:      pointer to an object specific debug description structure
 360  */
 361 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 362 {
 363         if (!debug_objects_enabled)
 364                 return;
 365
 366         __debug_object_init(addr, descr, 0);
 367 }
 368 EXPORT_SYMBOL_GPL(debug_object_init);
 369
 370 /**
 371  * debug_object_init_on_stack - debug checks when an object on stack is
 372  *                              initialized
 373  * @addr:       address of the object
 374  * @descr:      pointer to an object specific debug description structure
 375  */
 376 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 377 {
 378         if (!debug_objects_enabled)
 379                 return;
 380
 381         __debug_object_init(addr, descr, 1);
 382 }
 383 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 384
 385 /**
 386  * debug_object_activate - debug checks when an object is activated
 387  * @addr:       address of the object
 388  * @descr:      pointer to an object specific debug description structure
 389  * Returns 0 for success, -EINVAL for check failed.
 390  */
 391 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 392 {
 393         enum debug_obj_state state;
 394         struct debug_bucket *db;
 395         struct debug_obj *obj;
 396         unsigned long flags;
 397         int ret;
 398         struct debug_obj o = { .object = addr,
 399                                .state = ODEBUG_STATE_NOTAVAILABLE,
 400                                .descr = descr };
 401
 402         if (!debug_objects_enabled)
 403                 return 0;
 404
 405         db = get_bucket((unsigned long) addr);
 406
 407         raw_spin_lock_irqsave(&db->lock, flags);
 408
 409         obj = lookup_object(addr, db);
 410         if (obj) {
 411                 switch (obj->state) {
 412                 case ODEBUG_STATE_INIT:
 413                 case ODEBUG_STATE_INACTIVE:
 414                         obj->state = ODEBUG_STATE_ACTIVE;
 415                         ret = 0;
 416                         break;
 417
 418                 case ODEBUG_STATE_ACTIVE:
 419                         debug_print_object(obj, "activate");
 420                         state = obj->state;
 421                         raw_spin_unlock_irqrestore(&db->lock, flags);
 422                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 423                         return ret ? 0 : -EINVAL;
 424
 425                 case ODEBUG_STATE_DESTROYED:
 426                         debug_print_object(obj, "activate");
 427                         ret = -EINVAL;
 428                         break;
 429                 default:
 430                         ret = 0;
 431                         break;
 432                 }
 433                 raw_spin_unlock_irqrestore(&db->lock, flags);
 434                 return ret;
 435         }
 436
 437         raw_spin_unlock_irqrestore(&db->lock, flags);
 438         /*
 439          * We are here when a static object is activated. We
 440          * let the type specific code confirm whether this is
 441          * true or not. if true, we just make sure that the
 442          * static object is tracked in the object tracker. If
 443          * not, this must be a bug, so we try to fix it up.
 444          */
 445         if (descr->is_static_object && descr->is_static_object(addr)) {
 446                 /* track this static object */
 447                 debug_object_init(addr, descr);
 448                 debug_object_activate(addr, descr);
 449         } else {
 450                 debug_print_object(&o, "activate");
 451                 ret = debug_object_fixup(descr->fixup_activate, addr,
 452                                         ODEBUG_STATE_NOTAVAILABLE);
 453                 return ret ? 0 : -EINVAL;
 454         }
 455         return 0;
 456 }
 457 EXPORT_SYMBOL_GPL(debug_object_activate);
 458
 459 /**
 460  * debug_object_deactivate - debug checks when an object is deactivated
 461  * @addr:       address of the object
 462  * @descr:      pointer to an object specific debug description structure
 463  */
 464 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 465 {
 466         struct debug_bucket *db;
 467         struct debug_obj *obj;
 468         unsigned long flags;
 469
 470         if (!debug_objects_enabled)
 471                 return;
 472
 473         db = get_bucket((unsigned long) addr);
 474
 475         raw_spin_lock_irqsave(&db->lock, flags);
 476
 477         obj = lookup_object(addr, db);
 478         if (obj) {
 479                 switch (obj->state) {
 480                 case ODEBUG_STATE_INIT:
 481                 case ODEBUG_STATE_INACTIVE:
 482                 case ODEBUG_STATE_ACTIVE:
 483                         if (!obj->astate)
 484                                 obj->state = ODEBUG_STATE_INACTIVE;
 485                         else
 486                                 debug_print_object(obj, "deactivate");
 487                         break;
 488
 489                 case ODEBUG_STATE_DESTROYED:
 490                         debug_print_object(obj, "deactivate");
 491                         break;
 492                 default:
 493                         break;
 494                 }
 495         } else {
 496                 struct debug_obj o = { .object = addr,
 497                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 498                                        .descr = descr };
 499
 500                 debug_print_object(&o, "deactivate");
 501         }
 502
 503         raw_spin_unlock_irqrestore(&db->lock, flags);
 504 }
 505 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 506
 507 /**
 508  * debug_object_destroy - debug checks when an object is destroyed
 509  * @addr:       address of the object
 510  * @descr:      pointer to an object specific debug description structure
 511  */
 512 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 513 {
 514         enum debug_obj_state state;
 515         struct debug_bucket *db;
 516         struct debug_obj *obj;
 517         unsigned long flags;
 518
 519         if (!debug_objects_enabled)
 520                 return;
 521
 522         db = get_bucket((unsigned long) addr);
 523
 524         raw_spin_lock_irqsave(&db->lock, flags);
 525
 526         obj = lookup_object(addr, db);
 527         if (!obj)
 528                 goto out_unlock;
 529
 530         switch (obj->state) {
 531         case ODEBUG_STATE_NONE:
 532         case ODEBUG_STATE_INIT:
 533         case ODEBUG_STATE_INACTIVE:
 534                 obj->state = ODEBUG_STATE_DESTROYED;
 535                 break;
 536         case ODEBUG_STATE_ACTIVE:
 537                 debug_print_object(obj, "destroy");
 538                 state = obj->state;
 539                 raw_spin_unlock_irqrestore(&db->lock, flags);
 540                 debug_object_fixup(descr->fixup_destroy, addr, state);
 541                 return;
 542
 543         case ODEBUG_STATE_DESTROYED:
 544                 debug_print_object(obj, "destroy");
 545                 break;
 546         default:
 547                 break;
 548         }
 549 out_unlock:
 550         raw_spin_unlock_irqrestore(&db->lock, flags);
 551 }
 552 EXPORT_SYMBOL_GPL(debug_object_destroy);
 553
 554 /**
 555  * debug_object_free - debug checks when an object is freed
 556  * @addr:       address of the object
 557  * @descr:      pointer to an object specific debug description structure
 558  */
 559 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 560 {
 561         enum debug_obj_state state;
 562         struct debug_bucket *db;
 563         struct debug_obj *obj;
 564         unsigned long flags;
 565
 566         if (!debug_objects_enabled)
 567                 return;
 568
 569         db = get_bucket((unsigned long) addr);
 570
 571         raw_spin_lock_irqsave(&db->lock, flags);
 572
 573         obj = lookup_object(addr, db);
 574         if (!obj)
 575                 goto out_unlock;
 576
 577         switch (obj->state) {
 578         case ODEBUG_STATE_ACTIVE:
 579                 debug_print_object(obj, "free");
 580                 state = obj->state;
 581                 raw_spin_unlock_irqrestore(&db->lock, flags);
 582                 debug_object_fixup(descr->fixup_free, addr, state);
 583                 return;
 584         default:
 585                 hlist_del(&obj->node);
 586                 raw_spin_unlock_irqrestore(&db->lock, flags);
 587                 free_object(obj);
 588                 return;
 589         }
 590 out_unlock:
 591         raw_spin_unlock_irqrestore(&db->lock, flags);
 592 }
 593 EXPORT_SYMBOL_GPL(debug_object_free);
 594
 595 /**
 596  * debug_object_assert_init - debug checks when object should be init-ed
 597  * @addr:       address of the object
 598  * @descr:      pointer to an object specific debug description structure
 599  */
 600 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 601 {
 602         struct debug_bucket *db;
 603         struct debug_obj *obj;
 604         unsigned long flags;
 605
 606         if (!debug_objects_enabled)
 607                 return;
 608
 609         db = get_bucket((unsigned long) addr);
 610
 611         raw_spin_lock_irqsave(&db->lock, flags);
 612
 613         obj = lookup_object(addr, db);
 614         if (!obj) {
 615                 struct debug_obj o = { .object = addr,
 616                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 617                                        .descr = descr };
 618
 619                 raw_spin_unlock_irqrestore(&db->lock, flags);
 620                 /*
 621                  * Maybe the object is static, and we let the type specific
 622                  * code confirm. Track this static object if true, else invoke
 623                  * fixup.
 624                  */
 625                 if (descr->is_static_object && descr->is_static_object(addr)) {
 626                         /* Track this static object */
 627                         debug_object_init(addr, descr);
 628                 } else {
 629                         debug_print_object(&o, "assert_init");
 630                         debug_object_fixup(descr->fixup_assert_init, addr,
 631                                            ODEBUG_STATE_NOTAVAILABLE);
 632                 }
 633                 return;
 634         }
 635
 636         raw_spin_unlock_irqrestore(&db->lock, flags);
 637 }
 638 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 639
 640 /**
 641  * debug_object_active_state - debug checks object usage state machine
 642  * @addr:       address of the object
 643  * @descr:      pointer to an object specific debug description structure
 644  * @expect:     expected state
 645  * @next:       state to move to if expected state is found
 646  */
 647 void
 648 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 649                           unsigned int expect, unsigned int next)
 650 {
 651         struct debug_bucket *db;
 652         struct debug_obj *obj;
 653         unsigned long flags;
 654
 655         if (!debug_objects_enabled)
 656                 return;
 657
 658         db = get_bucket((unsigned long) addr);
 659
 660         raw_spin_lock_irqsave(&db->lock, flags);
 661
 662         obj = lookup_object(addr, db);
 663         if (obj) {
 664                 switch (obj->state) {
 665                 case ODEBUG_STATE_ACTIVE:
 666                         if (obj->astate == expect)
 667                                 obj->astate = next;
 668                         else
 669                                 debug_print_object(obj, "active_state");
 670                         break;
 671
 672                 default:
 673                         debug_print_object(obj, "active_state");
 674                         break;
 675                 }
 676         } else {
 677                 struct debug_obj o = { .object = addr,
 678                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 679                                        .descr = descr };
 680
 681                 debug_print_object(&o, "active_state");
 682         }
 683
 684         raw_spin_unlock_irqrestore(&db->lock, flags);
 685 }
 686 EXPORT_SYMBOL_GPL(debug_object_active_state);
 687
 688 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 689 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 690 {
 691         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 692         struct hlist_node *tmp;
 693         HLIST_HEAD(freelist);
 694         struct debug_obj_descr *descr;
 695         enum debug_obj_state state;
 696         struct debug_bucket *db;
 697         struct debug_obj *obj;
 698         int cnt;
 699
 700         saddr = (unsigned long) address;
 701         eaddr = saddr + size;
 702         paddr = saddr & ODEBUG_CHUNK_MASK;
 703         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 704         chunks >>= ODEBUG_CHUNK_SHIFT;
 705
 706         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 707                 db = get_bucket(paddr);
 708
 709 repeat:
 710                 cnt = 0;
 711                 raw_spin_lock_irqsave(&db->lock, flags);
 712                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 713                         cnt++;
 714                         oaddr = (unsigned long) obj->object;
 715                         if (oaddr < saddr || oaddr >= eaddr)
 716                                 continue;
 717
 718                         switch (obj->state) {
 719                         case ODEBUG_STATE_ACTIVE:
 720                                 debug_print_object(obj, "free");
 721                                 descr = obj->descr;
 722                                 state = obj->state;
 723                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 724                                 debug_object_fixup(descr->fixup_free,
 725                                                    (void *) oaddr, state);
 726                                 goto repeat;
 727                         default:
 728                                 hlist_del(&obj->node);
 729                                 hlist_add_head(&obj->node, &freelist);
 730                                 break;
 731                         }
 732                 }
 733                 raw_spin_unlock_irqrestore(&db->lock, flags);
 734
 735                 /* Now free them */
 736                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 737                         hlist_del(&obj->node);
 738                         free_object(obj);
 739                 }
 740
 741                 if (cnt > debug_objects_maxchain)
 742                         debug_objects_maxchain = cnt;
 743         }
 744 }
 745
 746 void debug_check_no_obj_freed(const void *address, unsigned long size)
 747 {
 748         if (debug_objects_enabled)
 749                 __debug_check_no_obj_freed(address, size);
 750 }
 751 #endif
 752
 753 #ifdef CONFIG_DEBUG_FS
 754
 755 static int debug_stats_show(struct seq_file *m, void *v)
 756 {
 757         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 758         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 759         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 760         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 761         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 762         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 763         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 764         return 0;
 765 }
 766
 767 static int debug_stats_open(struct inode *inode, struct file *filp)
 768 {
 769         return single_open(filp, debug_stats_show, NULL);
 770 }
 771
 772 static const struct file_operations debug_stats_fops = {
 773         .open           = debug_stats_open,
 774         .read           = seq_read,
 775         .llseek         = seq_lseek,
 776         .release        = single_release,
 777 };
 778
 779 static int __init debug_objects_init_debugfs(void)
 780 {
 781         struct dentry *dbgdir, *dbgstats;
 782
 783         if (!debug_objects_enabled)
 784                 return 0;
 785
 786         dbgdir = debugfs_create_dir("debug_objects", NULL);
 787         if (!dbgdir)
 788                 return -ENOMEM;
 789
 790         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 791                                        &debug_stats_fops);
 792         if (!dbgstats)
 793                 goto err;
 794
 795         return 0;
 796
 797 err:
 798         debugfs_remove(dbgdir);
 799
 800         return -ENOMEM;
 801 }
 802 __initcall(debug_objects_init_debugfs);
 803
 804 #else
 805 static inline void debug_objects_init_debugfs(void) { }
 806 #endif
 807
 808 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 809
 810 /* Random data structure for the self test */
 811 struct self_test {
 812         unsigned long   dummy1[6];
 813         int             static_init;
 814         unsigned long   dummy2[3];
 815 };
 816
 817 static __initdata struct debug_obj_descr descr_type_test;
 818
 819 static bool __init is_static_object(void *addr)
 820 {
 821         struct self_test *obj = addr;
 822
 823         return obj->static_init;
 824 }
 825
 826 /*
 827  * fixup_init is called when:
 828  * - an active object is initialized
 829  */
 830 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 831 {
 832         struct self_test *obj = addr;
 833
 834         switch (state) {
 835         case ODEBUG_STATE_ACTIVE:
 836                 debug_object_deactivate(obj, &descr_type_test);
 837                 debug_object_init(obj, &descr_type_test);
 838                 return true;
 839         default:
 840                 return false;
 841         }
 842 }
 843
 844 /*
 845  * fixup_activate is called when:
 846  * - an active object is activated
 847  * - an unknown non-static object is activated
 848  */
 849 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 850 {
 851         struct self_test *obj = addr;
 852
 853         switch (state) {
 854         case ODEBUG_STATE_NOTAVAILABLE:
 855                 return true;
 856         case ODEBUG_STATE_ACTIVE:
 857                 debug_object_deactivate(obj, &descr_type_test);
 858                 debug_object_activate(obj, &descr_type_test);
 859                 return true;
 860
 861         default:
 862                 return false;
 863         }
 864 }
 865
 866 /*
 867  * fixup_destroy is called when:
 868  * - an active object is destroyed
 869  */
 870 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 871 {
 872         struct self_test *obj = addr;
 873
 874         switch (state) {
 875         case ODEBUG_STATE_ACTIVE:
 876                 debug_object_deactivate(obj, &descr_type_test);
 877                 debug_object_destroy(obj, &descr_type_test);
 878                 return true;
 879         default:
 880                 return false;
 881         }
 882 }
 883
 884 /*
 885  * fixup_free is called when:
 886  * - an active object is freed
 887  */
 888 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 889 {
 890         struct self_test *obj = addr;
 891
 892         switch (state) {
 893         case ODEBUG_STATE_ACTIVE:
 894                 debug_object_deactivate(obj, &descr_type_test);
 895                 debug_object_free(obj, &descr_type_test);
 896                 return true;
 897         default:
 898                 return false;
 899         }
 900 }
 901
 902 static int __init
 903 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 904 {
 905         struct debug_bucket *db;
 906         struct debug_obj *obj;
 907         unsigned long flags;
 908         int res = -EINVAL;
 909
 910         db = get_bucket((unsigned long) addr);
 911
 912         raw_spin_lock_irqsave(&db->lock, flags);
 913
 914         obj = lookup_object(addr, db);
 915         if (!obj && state != ODEBUG_STATE_NONE) {
 916                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 917                 goto out;
 918         }
 919         if (obj && obj->state != state) {
 920                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 921                        obj->state, state);
 922                 goto out;
 923         }
 924         if (fixups != debug_objects_fixups) {
 925                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 926                        fixups, debug_objects_fixups);
 927                 goto out;
 928         }
 929         if (warnings != debug_objects_warnings) {
 930                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 931                        warnings, debug_objects_warnings);
 932                 goto out;
 933         }
 934         res = 0;
 935 out:
 936         raw_spin_unlock_irqrestore(&db->lock, flags);
 937         if (res)
 938                 debug_objects_enabled = 0;
 939         return res;
 940 }
 941
 942 static __initdata struct debug_obj_descr descr_type_test = {
 943         .name                   = "selftest",
 944         .is_static_object       = is_static_object,
 945         .fixup_init             = fixup_init,
 946         .fixup_activate         = fixup_activate,
 947         .fixup_destroy          = fixup_destroy,
 948         .fixup_free             = fixup_free,
 949 };
 950
 951 static __initdata struct self_test obj = { .static_init = 0 };
 952
 953 static void __init debug_objects_selftest(void)
 954 {
 955         int fixups, oldfixups, warnings, oldwarnings;
 956         unsigned long flags;
 957
 958         local_irq_save(flags);
 959
 960         fixups = oldfixups = debug_objects_fixups;
 961         warnings = oldwarnings = debug_objects_warnings;
 962         descr_test = &descr_type_test;
 963
 964         debug_object_init(&obj, &descr_type_test);
 965         if (check_results(&obj, ODEBUG_STATE_INIT, 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_activate(&obj, &descr_type_test);
 971         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 972                 goto out;
 973         debug_object_deactivate(&obj, &descr_type_test);
 974         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 975                 goto out;
 976         debug_object_destroy(&obj, &descr_type_test);
 977         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 978                 goto out;
 979         debug_object_init(&obj, &descr_type_test);
 980         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 981                 goto out;
 982         debug_object_activate(&obj, &descr_type_test);
 983         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 984                 goto out;
 985         debug_object_deactivate(&obj, &descr_type_test);
 986         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 987                 goto out;
 988         debug_object_free(&obj, &descr_type_test);
 989         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 990                 goto out;
 991
 992         obj.static_init = 1;
 993         debug_object_activate(&obj, &descr_type_test);
 994         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 995                 goto out;
 996         debug_object_init(&obj, &descr_type_test);
 997         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
 998                 goto out;
 999         debug_object_free(&obj, &descr_type_test);
1000         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1001                 goto out;
1002
1003 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1004         debug_object_init(&obj, &descr_type_test);
1005         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1006                 goto out;
1007         debug_object_activate(&obj, &descr_type_test);
1008         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1009                 goto out;
1010         __debug_check_no_obj_freed(&obj, sizeof(obj));
1011         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1012                 goto out;
1013 #endif
1014         pr_info("selftest passed\n");
1015
1016 out:
1017         debug_objects_fixups = oldfixups;
1018         debug_objects_warnings = oldwarnings;
1019         descr_test = NULL;
1020
1021         local_irq_restore(flags);
1022 }
1023 #else
1024 static inline void debug_objects_selftest(void) { }
1025 #endif
1026
1027 /*
1028  * Called during early boot to initialize the hash buckets and link
1029  * the static object pool objects into the poll list. After this call
1030  * the object tracker is fully operational.
1031  */
1032 void __init debug_objects_early_init(void)
1033 {
1034         int i;
1035
1036         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1037                 raw_spin_lock_init(&obj_hash[i].lock);
1038
1039         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1040                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1041 }
1042
1043 /*
1044  * Convert the statically allocated objects to dynamic ones:
1045  */
1046 static int __init debug_objects_replace_static_objects(void)
1047 {
1048         struct debug_bucket *db = obj_hash;
1049         struct hlist_node *tmp;
1050         struct debug_obj *obj, *new;
1051         HLIST_HEAD(objects);
1052         int i, cnt = 0;
1053
1054         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1055                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1056                 if (!obj)
1057                         goto free;
1058                 hlist_add_head(&obj->node, &objects);
1059         }
1060
1061         /*
1062          * When debug_objects_mem_init() is called we know that only
1063          * one CPU is up, so disabling interrupts is enough
1064          * protection. This avoids the lockdep hell of lock ordering.
1065          */
1066         local_irq_disable();
1067
1068         /* Remove the statically allocated objects from the pool */
1069         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1070                 hlist_del(&obj->node);
1071         /* Move the allocated objects to the pool */
1072         hlist_move_list(&objects, &obj_pool);
1073
1074         /* Replace the active object references */
1075         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1076                 hlist_move_list(&db->list, &objects);
1077
1078                 hlist_for_each_entry(obj, &objects, node) {
1079                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1080                         hlist_del(&new->node);
1081                         /* copy object data */
1082                         *new = *obj;
1083                         hlist_add_head(&new->node, &db->list);
1084                         cnt++;
1085                 }
1086         }
1087         local_irq_enable();
1088
1089         pr_debug("%d of %d active objects replaced\n",
1090                  cnt, obj_pool_used);
1091         return 0;
1092 free:
1093         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1094                 hlist_del(&obj->node);
1095                 kmem_cache_free(obj_cache, obj);
1096         }
1097         return -ENOMEM;
1098 }
1099
1100 /*
1101  * Called after the kmem_caches are functional to setup a dedicated
1102  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1103  * prevents that the debug code is called on kmem_cache_free() for the
1104  * debug tracker objects to avoid recursive calls.
1105  */
1106 void __init debug_objects_mem_init(void)
1107 {
1108         if (!debug_objects_enabled)
1109                 return;
1110
1111         obj_cache = kmem_cache_create("debug_objects_cache",
1112                                       sizeof (struct debug_obj), 0,
1113                                       SLAB_DEBUG_OBJECTS, NULL);
1114
1115         if (!obj_cache || debug_objects_replace_static_objects()) {
1116                 debug_objects_enabled = 0;
1117                 if (obj_cache)
1118                         kmem_cache_destroy(obj_cache);
1119                 pr_warn("out of memory.\n");
1120         } else
1121                 debug_objects_selftest();
1122 }