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