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/sched/task_stack.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/slab.h>
  20 #include <linux/hash.h>
  21 #include <linux/kmemleak.h>
  22
  23 #define ODEBUG_HASH_BITS        14
  24 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  25
  26 #define ODEBUG_POOL_SIZE        1024
  27 #define ODEBUG_POOL_MIN_LEVEL   256
  28
  29 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  30 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  31 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  32
  33 struct debug_bucket {
  34         struct hlist_head       list;
  35         raw_spinlock_t          lock;
  36 };
  37
  38 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  39
  40 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  41
  42 static DEFINE_RAW_SPINLOCK(pool_lock);
  43
  44 static HLIST_HEAD(obj_pool);
  45
  46 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  47 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  48 static int                      obj_pool_used;
  49 static int                      obj_pool_max_used;
  50 static struct kmem_cache        *obj_cache;
  51
  52 static int                      debug_objects_maxchain __read_mostly;
  53 static int                      debug_objects_fixups __read_mostly;
  54 static int                      debug_objects_warnings __read_mostly;
  55 static int                      debug_objects_enabled __read_mostly
  56                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  57 static int                      debug_objects_pool_size __read_mostly
  58                                 = ODEBUG_POOL_SIZE;
  59 static int                      debug_objects_pool_min_level __read_mostly
  60                                 = ODEBUG_POOL_MIN_LEVEL;
  61 static struct debug_obj_descr   *descr_test  __read_mostly;
  62
  63 /*
  64  * Track numbers of kmem_cache_alloc()/free() calls done.
  65  */
  66 static int                      debug_objects_allocated;
  67 static int                      debug_objects_freed;
  68
  69 static void free_obj_work(struct work_struct *work);
  70 static DECLARE_WORK(debug_obj_work, free_obj_work);
  71
  72 static int __init enable_object_debug(char *str)
  73 {
  74         debug_objects_enabled = 1;
  75         return 0;
  76 }
  77
  78 static int __init disable_object_debug(char *str)
  79 {
  80         debug_objects_enabled = 0;
  81         return 0;
  82 }
  83
  84 early_param("debug_objects", enable_object_debug);
  85 early_param("no_debug_objects", disable_object_debug);
  86
  87 static const char *obj_states[ODEBUG_STATE_MAX] = {
  88         [ODEBUG_STATE_NONE]             = "none",
  89         [ODEBUG_STATE_INIT]             = "initialized",
  90         [ODEBUG_STATE_INACTIVE]         = "inactive",
  91         [ODEBUG_STATE_ACTIVE]           = "active",
  92         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  93         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  94 };
  95
  96 static void fill_pool(void)
  97 {
  98         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  99         struct debug_obj *new;
 100         unsigned long flags;
 101
 102         if (likely(obj_pool_free >= debug_objects_pool_min_level))
 103                 return;
 104
 105         if (unlikely(!obj_cache))
 106                 return;
 107
 108         while (obj_pool_free < debug_objects_pool_min_level) {
 109
 110                 new = kmem_cache_zalloc(obj_cache, gfp);
 111                 if (!new)
 112                         return;
 113
 114                 raw_spin_lock_irqsave(&pool_lock, flags);
 115                 hlist_add_head(&new->node, &obj_pool);
 116                 debug_objects_allocated++;
 117                 obj_pool_free++;
 118                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 119         }
 120 }
 121
 122 /*
 123  * Lookup an object in the hash bucket.
 124  */
 125 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 126 {
 127         struct debug_obj *obj;
 128         int cnt = 0;
 129
 130         hlist_for_each_entry(obj, &b->list, node) {
 131                 cnt++;
 132                 if (obj->object == addr)
 133                         return obj;
 134         }
 135         if (cnt > debug_objects_maxchain)
 136                 debug_objects_maxchain = cnt;
 137
 138         return NULL;
 139 }
 140
 141 /*
 142  * Allocate a new object. If the pool is empty, switch off the debugger.
 143  * Must be called with interrupts disabled.
 144  */
 145 static struct debug_obj *
 146 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 147 {
 148         struct debug_obj *obj = NULL;
 149
 150         raw_spin_lock(&pool_lock);
 151         if (obj_pool.first) {
 152                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 153
 154                 obj->object = addr;
 155                 obj->descr  = descr;
 156                 obj->state  = ODEBUG_STATE_NONE;
 157                 obj->astate = 0;
 158                 hlist_del(&obj->node);
 159
 160                 hlist_add_head(&obj->node, &b->list);
 161
 162                 obj_pool_used++;
 163                 if (obj_pool_used > obj_pool_max_used)
 164                         obj_pool_max_used = obj_pool_used;
 165
 166                 obj_pool_free--;
 167                 if (obj_pool_free < obj_pool_min_free)
 168                         obj_pool_min_free = obj_pool_free;
 169         }
 170         raw_spin_unlock(&pool_lock);
 171
 172         return obj;
 173 }
 174
 175 /*
 176  * workqueue function to free objects.
 177  *
 178  * To reduce contention on the global pool_lock, the actual freeing of
 179  * debug objects will be delayed if the pool_lock is busy. We also free
 180  * the objects in a batch of 4 for each lock/unlock cycle.
 181  */
 182 #define ODEBUG_FREE_BATCH       4
 183
 184 static void free_obj_work(struct work_struct *work)
 185 {
 186         struct debug_obj *objs[ODEBUG_FREE_BATCH];
 187         unsigned long flags;
 188         int i;
 189
 190         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 191                 return;
 192         while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) {
 193                 for (i = 0; i < ODEBUG_FREE_BATCH; i++) {
 194                         objs[i] = hlist_entry(obj_pool.first,
 195                                               typeof(*objs[0]), node);
 196                         hlist_del(&objs[i]->node);
 197                 }
 198
 199                 obj_pool_free -= ODEBUG_FREE_BATCH;
 200                 debug_objects_freed += ODEBUG_FREE_BATCH;
 201                 /*
 202                  * We release pool_lock across kmem_cache_free() to
 203                  * avoid contention on pool_lock.
 204                  */
 205                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 206                 for (i = 0; i < ODEBUG_FREE_BATCH; i++)
 207                         kmem_cache_free(obj_cache, objs[i]);
 208                 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 209                         return;
 210         }
 211         raw_spin_unlock_irqrestore(&pool_lock, flags);
 212 }
 213
 214 /*
 215  * Put the object back into the pool and schedule work to free objects
 216  * if necessary.
 217  */
 218 static void free_object(struct debug_obj *obj)
 219 {
 220         unsigned long flags;
 221         int sched = 0;
 222
 223         raw_spin_lock_irqsave(&pool_lock, flags);
 224         /*
 225          * schedule work when the pool is filled and the cache is
 226          * initialized:
 227          */
 228         if (obj_pool_free > debug_objects_pool_size && obj_cache)
 229                 sched = 1;
 230         hlist_add_head(&obj->node, &obj_pool);
 231         obj_pool_free++;
 232         obj_pool_used--;
 233         raw_spin_unlock_irqrestore(&pool_lock, flags);
 234         if (sched)
 235                 schedule_work(&debug_obj_work);
 236 }
 237
 238 /*
 239  * We run out of memory. That means we probably have tons of objects
 240  * allocated.
 241  */
 242 static void debug_objects_oom(void)
 243 {
 244         struct debug_bucket *db = obj_hash;
 245         struct hlist_node *tmp;
 246         HLIST_HEAD(freelist);
 247         struct debug_obj *obj;
 248         unsigned long flags;
 249         int i;
 250
 251         pr_warn("Out of memory. ODEBUG disabled\n");
 252
 253         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 254                 raw_spin_lock_irqsave(&db->lock, flags);
 255                 hlist_move_list(&db->list, &freelist);
 256                 raw_spin_unlock_irqrestore(&db->lock, flags);
 257
 258                 /* Now free them */
 259                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 260                         hlist_del(&obj->node);
 261                         free_object(obj);
 262                 }
 263         }
 264 }
 265
 266 /*
 267  * We use the pfn of the address for the hash. That way we can check
 268  * for freed objects simply by checking the affected bucket.
 269  */
 270 static struct debug_bucket *get_bucket(unsigned long addr)
 271 {
 272         unsigned long hash;
 273
 274         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 275         return &obj_hash[hash];
 276 }
 277
 278 static void debug_print_object(struct debug_obj *obj, char *msg)
 279 {
 280         struct debug_obj_descr *descr = obj->descr;
 281         static int limit;
 282
 283         if (limit < 5 && descr != descr_test) {
 284                 void *hint = descr->debug_hint ?
 285                         descr->debug_hint(obj->object) : NULL;
 286                 limit++;
 287                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 288                                  "object type: %s hint: %pS\n",
 289                         msg, obj_states[obj->state], obj->astate,
 290                         descr->name, hint);
 291         }
 292         debug_objects_warnings++;
 293 }
 294
 295 /*
 296  * Try to repair the damage, so we have a better chance to get useful
 297  * debug output.
 298  */
 299 static bool
 300 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 301                    void * addr, enum debug_obj_state state)
 302 {
 303         if (fixup && fixup(addr, state)) {
 304                 debug_objects_fixups++;
 305                 return true;
 306         }
 307         return false;
 308 }
 309
 310 static void debug_object_is_on_stack(void *addr, int onstack)
 311 {
 312         int is_on_stack;
 313         static int limit;
 314
 315         if (limit > 4)
 316                 return;
 317
 318         is_on_stack = object_is_on_stack(addr);
 319         if (is_on_stack == onstack)
 320                 return;
 321
 322         limit++;
 323         if (is_on_stack)
 324                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 325                          task_stack_page(current));
 326         else
 327                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 328                          task_stack_page(current));
 329
 330         WARN_ON(1);
 331 }
 332
 333 static void
 334 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 335 {
 336         enum debug_obj_state state;
 337         struct debug_bucket *db;
 338         struct debug_obj *obj;
 339         unsigned long flags;
 340
 341         fill_pool();
 342
 343         db = get_bucket((unsigned long) addr);
 344
 345         raw_spin_lock_irqsave(&db->lock, flags);
 346
 347         obj = lookup_object(addr, db);
 348         if (!obj) {
 349                 obj = alloc_object(addr, db, descr);
 350                 if (!obj) {
 351                         debug_objects_enabled = 0;
 352                         raw_spin_unlock_irqrestore(&db->lock, flags);
 353                         debug_objects_oom();
 354                         return;
 355                 }
 356                 debug_object_is_on_stack(addr, onstack);
 357         }
 358
 359         switch (obj->state) {
 360         case ODEBUG_STATE_NONE:
 361         case ODEBUG_STATE_INIT:
 362         case ODEBUG_STATE_INACTIVE:
 363                 obj->state = ODEBUG_STATE_INIT;
 364                 break;
 365
 366         case ODEBUG_STATE_ACTIVE:
 367                 debug_print_object(obj, "init");
 368                 state = obj->state;
 369                 raw_spin_unlock_irqrestore(&db->lock, flags);
 370                 debug_object_fixup(descr->fixup_init, addr, state);
 371                 return;
 372
 373         case ODEBUG_STATE_DESTROYED:
 374                 debug_print_object(obj, "init");
 375                 break;
 376         default:
 377                 break;
 378         }
 379
 380         raw_spin_unlock_irqrestore(&db->lock, flags);
 381 }
 382
 383 /**
 384  * debug_object_init - debug checks when an object is initialized
 385  * @addr:       address of the object
 386  * @descr:      pointer to an object specific debug description structure
 387  */
 388 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 389 {
 390         if (!debug_objects_enabled)
 391                 return;
 392
 393         __debug_object_init(addr, descr, 0);
 394 }
 395 EXPORT_SYMBOL_GPL(debug_object_init);
 396
 397 /**
 398  * debug_object_init_on_stack - debug checks when an object on stack is
 399  *                              initialized
 400  * @addr:       address of the object
 401  * @descr:      pointer to an object specific debug description structure
 402  */
 403 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 404 {
 405         if (!debug_objects_enabled)
 406                 return;
 407
 408         __debug_object_init(addr, descr, 1);
 409 }
 410 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 411
 412 /**
 413  * debug_object_activate - debug checks when an object is activated
 414  * @addr:       address of the object
 415  * @descr:      pointer to an object specific debug description structure
 416  * Returns 0 for success, -EINVAL for check failed.
 417  */
 418 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 419 {
 420         enum debug_obj_state state;
 421         struct debug_bucket *db;
 422         struct debug_obj *obj;
 423         unsigned long flags;
 424         int ret;
 425         struct debug_obj o = { .object = addr,
 426                                .state = ODEBUG_STATE_NOTAVAILABLE,
 427                                .descr = descr };
 428
 429         if (!debug_objects_enabled)
 430                 return 0;
 431
 432         db = get_bucket((unsigned long) addr);
 433
 434         raw_spin_lock_irqsave(&db->lock, flags);
 435
 436         obj = lookup_object(addr, db);
 437         if (obj) {
 438                 switch (obj->state) {
 439                 case ODEBUG_STATE_INIT:
 440                 case ODEBUG_STATE_INACTIVE:
 441                         obj->state = ODEBUG_STATE_ACTIVE;
 442                         ret = 0;
 443                         break;
 444
 445                 case ODEBUG_STATE_ACTIVE:
 446                         debug_print_object(obj, "activate");
 447                         state = obj->state;
 448                         raw_spin_unlock_irqrestore(&db->lock, flags);
 449                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 450                         return ret ? 0 : -EINVAL;
 451
 452                 case ODEBUG_STATE_DESTROYED:
 453                         debug_print_object(obj, "activate");
 454                         ret = -EINVAL;
 455                         break;
 456                 default:
 457                         ret = 0;
 458                         break;
 459                 }
 460                 raw_spin_unlock_irqrestore(&db->lock, flags);
 461                 return ret;
 462         }
 463
 464         raw_spin_unlock_irqrestore(&db->lock, flags);
 465         /*
 466          * We are here when a static object is activated. We
 467          * let the type specific code confirm whether this is
 468          * true or not. if true, we just make sure that the
 469          * static object is tracked in the object tracker. If
 470          * not, this must be a bug, so we try to fix it up.
 471          */
 472         if (descr->is_static_object && descr->is_static_object(addr)) {
 473                 /* track this static object */
 474                 debug_object_init(addr, descr);
 475                 debug_object_activate(addr, descr);
 476         } else {
 477                 debug_print_object(&o, "activate");
 478                 ret = debug_object_fixup(descr->fixup_activate, addr,
 479                                         ODEBUG_STATE_NOTAVAILABLE);
 480                 return ret ? 0 : -EINVAL;
 481         }
 482         return 0;
 483 }
 484 EXPORT_SYMBOL_GPL(debug_object_activate);
 485
 486 /**
 487  * debug_object_deactivate - debug checks when an object is deactivated
 488  * @addr:       address of the object
 489  * @descr:      pointer to an object specific debug description structure
 490  */
 491 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 492 {
 493         struct debug_bucket *db;
 494         struct debug_obj *obj;
 495         unsigned long flags;
 496
 497         if (!debug_objects_enabled)
 498                 return;
 499
 500         db = get_bucket((unsigned long) addr);
 501
 502         raw_spin_lock_irqsave(&db->lock, flags);
 503
 504         obj = lookup_object(addr, db);
 505         if (obj) {
 506                 switch (obj->state) {
 507                 case ODEBUG_STATE_INIT:
 508                 case ODEBUG_STATE_INACTIVE:
 509                 case ODEBUG_STATE_ACTIVE:
 510                         if (!obj->astate)
 511                                 obj->state = ODEBUG_STATE_INACTIVE;
 512                         else
 513                                 debug_print_object(obj, "deactivate");
 514                         break;
 515
 516                 case ODEBUG_STATE_DESTROYED:
 517                         debug_print_object(obj, "deactivate");
 518                         break;
 519                 default:
 520                         break;
 521                 }
 522         } else {
 523                 struct debug_obj o = { .object = addr,
 524                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 525                                        .descr = descr };
 526
 527                 debug_print_object(&o, "deactivate");
 528         }
 529
 530         raw_spin_unlock_irqrestore(&db->lock, flags);
 531 }
 532 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 533
 534 /**
 535  * debug_object_destroy - debug checks when an object is destroyed
 536  * @addr:       address of the object
 537  * @descr:      pointer to an object specific debug description structure
 538  */
 539 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 540 {
 541         enum debug_obj_state state;
 542         struct debug_bucket *db;
 543         struct debug_obj *obj;
 544         unsigned long flags;
 545
 546         if (!debug_objects_enabled)
 547                 return;
 548
 549         db = get_bucket((unsigned long) addr);
 550
 551         raw_spin_lock_irqsave(&db->lock, flags);
 552
 553         obj = lookup_object(addr, db);
 554         if (!obj)
 555                 goto out_unlock;
 556
 557         switch (obj->state) {
 558         case ODEBUG_STATE_NONE:
 559         case ODEBUG_STATE_INIT:
 560         case ODEBUG_STATE_INACTIVE:
 561                 obj->state = ODEBUG_STATE_DESTROYED;
 562                 break;
 563         case ODEBUG_STATE_ACTIVE:
 564                 debug_print_object(obj, "destroy");
 565                 state = obj->state;
 566                 raw_spin_unlock_irqrestore(&db->lock, flags);
 567                 debug_object_fixup(descr->fixup_destroy, addr, state);
 568                 return;
 569
 570         case ODEBUG_STATE_DESTROYED:
 571                 debug_print_object(obj, "destroy");
 572                 break;
 573         default:
 574                 break;
 575         }
 576 out_unlock:
 577         raw_spin_unlock_irqrestore(&db->lock, flags);
 578 }
 579 EXPORT_SYMBOL_GPL(debug_object_destroy);
 580
 581 /**
 582  * debug_object_free - debug checks when an object is freed
 583  * @addr:       address of the object
 584  * @descr:      pointer to an object specific debug description structure
 585  */
 586 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 587 {
 588         enum debug_obj_state state;
 589         struct debug_bucket *db;
 590         struct debug_obj *obj;
 591         unsigned long flags;
 592
 593         if (!debug_objects_enabled)
 594                 return;
 595
 596         db = get_bucket((unsigned long) addr);
 597
 598         raw_spin_lock_irqsave(&db->lock, flags);
 599
 600         obj = lookup_object(addr, db);
 601         if (!obj)
 602                 goto out_unlock;
 603
 604         switch (obj->state) {
 605         case ODEBUG_STATE_ACTIVE:
 606                 debug_print_object(obj, "free");
 607                 state = obj->state;
 608                 raw_spin_unlock_irqrestore(&db->lock, flags);
 609                 debug_object_fixup(descr->fixup_free, addr, state);
 610                 return;
 611         default:
 612                 hlist_del(&obj->node);
 613                 raw_spin_unlock_irqrestore(&db->lock, flags);
 614                 free_object(obj);
 615                 return;
 616         }
 617 out_unlock:
 618         raw_spin_unlock_irqrestore(&db->lock, flags);
 619 }
 620 EXPORT_SYMBOL_GPL(debug_object_free);
 621
 622 /**
 623  * debug_object_assert_init - debug checks when object should be init-ed
 624  * @addr:       address of the object
 625  * @descr:      pointer to an object specific debug description structure
 626  */
 627 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 628 {
 629         struct debug_bucket *db;
 630         struct debug_obj *obj;
 631         unsigned long flags;
 632
 633         if (!debug_objects_enabled)
 634                 return;
 635
 636         db = get_bucket((unsigned long) addr);
 637
 638         raw_spin_lock_irqsave(&db->lock, flags);
 639
 640         obj = lookup_object(addr, db);
 641         if (!obj) {
 642                 struct debug_obj o = { .object = addr,
 643                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 644                                        .descr = descr };
 645
 646                 raw_spin_unlock_irqrestore(&db->lock, flags);
 647                 /*
 648                  * Maybe the object is static, and we let the type specific
 649                  * code confirm. Track this static object if true, else invoke
 650                  * fixup.
 651                  */
 652                 if (descr->is_static_object && descr->is_static_object(addr)) {
 653                         /* Track this static object */
 654                         debug_object_init(addr, descr);
 655                 } else {
 656                         debug_print_object(&o, "assert_init");
 657                         debug_object_fixup(descr->fixup_assert_init, addr,
 658                                            ODEBUG_STATE_NOTAVAILABLE);
 659                 }
 660                 return;
 661         }
 662
 663         raw_spin_unlock_irqrestore(&db->lock, flags);
 664 }
 665 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 666
 667 /**
 668  * debug_object_active_state - debug checks object usage state machine
 669  * @addr:       address of the object
 670  * @descr:      pointer to an object specific debug description structure
 671  * @expect:     expected state
 672  * @next:       state to move to if expected state is found
 673  */
 674 void
 675 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 676                           unsigned int expect, unsigned int next)
 677 {
 678         struct debug_bucket *db;
 679         struct debug_obj *obj;
 680         unsigned long flags;
 681
 682         if (!debug_objects_enabled)
 683                 return;
 684
 685         db = get_bucket((unsigned long) addr);
 686
 687         raw_spin_lock_irqsave(&db->lock, flags);
 688
 689         obj = lookup_object(addr, db);
 690         if (obj) {
 691                 switch (obj->state) {
 692                 case ODEBUG_STATE_ACTIVE:
 693                         if (obj->astate == expect)
 694                                 obj->astate = next;
 695                         else
 696                                 debug_print_object(obj, "active_state");
 697                         break;
 698
 699                 default:
 700                         debug_print_object(obj, "active_state");
 701                         break;
 702                 }
 703         } else {
 704                 struct debug_obj o = { .object = addr,
 705                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 706                                        .descr = descr };
 707
 708                 debug_print_object(&o, "active_state");
 709         }
 710
 711         raw_spin_unlock_irqrestore(&db->lock, flags);
 712 }
 713 EXPORT_SYMBOL_GPL(debug_object_active_state);
 714
 715 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 716 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 717 {
 718         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 719         struct hlist_node *tmp;
 720         HLIST_HEAD(freelist);
 721         struct debug_obj_descr *descr;
 722         enum debug_obj_state state;
 723         struct debug_bucket *db;
 724         struct debug_obj *obj;
 725         int cnt;
 726
 727         saddr = (unsigned long) address;
 728         eaddr = saddr + size;
 729         paddr = saddr & ODEBUG_CHUNK_MASK;
 730         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 731         chunks >>= ODEBUG_CHUNK_SHIFT;
 732
 733         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 734                 db = get_bucket(paddr);
 735
 736 repeat:
 737                 cnt = 0;
 738                 raw_spin_lock_irqsave(&db->lock, flags);
 739                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 740                         cnt++;
 741                         oaddr = (unsigned long) obj->object;
 742                         if (oaddr < saddr || oaddr >= eaddr)
 743                                 continue;
 744
 745                         switch (obj->state) {
 746                         case ODEBUG_STATE_ACTIVE:
 747                                 debug_print_object(obj, "free");
 748                                 descr = obj->descr;
 749                                 state = obj->state;
 750                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 751                                 debug_object_fixup(descr->fixup_free,
 752                                                    (void *) oaddr, state);
 753                                 goto repeat;
 754                         default:
 755                                 hlist_del(&obj->node);
 756                                 hlist_add_head(&obj->node, &freelist);
 757                                 break;
 758                         }
 759                 }
 760                 raw_spin_unlock_irqrestore(&db->lock, flags);
 761
 762                 /* Now free them */
 763                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 764                         hlist_del(&obj->node);
 765                         free_object(obj);
 766                 }
 767
 768                 if (cnt > debug_objects_maxchain)
 769                         debug_objects_maxchain = cnt;
 770         }
 771 }
 772
 773 void debug_check_no_obj_freed(const void *address, unsigned long size)
 774 {
 775         if (debug_objects_enabled)
 776                 __debug_check_no_obj_freed(address, size);
 777 }
 778 #endif
 779
 780 #ifdef CONFIG_DEBUG_FS
 781
 782 static int debug_stats_show(struct seq_file *m, void *v)
 783 {
 784         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 785         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 786         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 787         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 788         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 789         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 790         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 791         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 792         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 793         return 0;
 794 }
 795
 796 static int debug_stats_open(struct inode *inode, struct file *filp)
 797 {
 798         return single_open(filp, debug_stats_show, NULL);
 799 }
 800
 801 static const struct file_operations debug_stats_fops = {
 802         .open           = debug_stats_open,
 803         .read           = seq_read,
 804         .llseek         = seq_lseek,
 805         .release        = single_release,
 806 };
 807
 808 static int __init debug_objects_init_debugfs(void)
 809 {
 810         struct dentry *dbgdir, *dbgstats;
 811
 812         if (!debug_objects_enabled)
 813                 return 0;
 814
 815         dbgdir = debugfs_create_dir("debug_objects", NULL);
 816         if (!dbgdir)
 817                 return -ENOMEM;
 818
 819         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 820                                        &debug_stats_fops);
 821         if (!dbgstats)
 822                 goto err;
 823
 824         return 0;
 825
 826 err:
 827         debugfs_remove(dbgdir);
 828
 829         return -ENOMEM;
 830 }
 831 __initcall(debug_objects_init_debugfs);
 832
 833 #else
 834 static inline void debug_objects_init_debugfs(void) { }
 835 #endif
 836
 837 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 838
 839 /* Random data structure for the self test */
 840 struct self_test {
 841         unsigned long   dummy1[6];
 842         int             static_init;
 843         unsigned long   dummy2[3];
 844 };
 845
 846 static __initdata struct debug_obj_descr descr_type_test;
 847
 848 static bool __init is_static_object(void *addr)
 849 {
 850         struct self_test *obj = addr;
 851
 852         return obj->static_init;
 853 }
 854
 855 /*
 856  * fixup_init is called when:
 857  * - an active object is initialized
 858  */
 859 static bool __init fixup_init(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_init(obj, &descr_type_test);
 867                 return true;
 868         default:
 869                 return false;
 870         }
 871 }
 872
 873 /*
 874  * fixup_activate is called when:
 875  * - an active object is activated
 876  * - an unknown non-static object is activated
 877  */
 878 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 879 {
 880         struct self_test *obj = addr;
 881
 882         switch (state) {
 883         case ODEBUG_STATE_NOTAVAILABLE:
 884                 return true;
 885         case ODEBUG_STATE_ACTIVE:
 886                 debug_object_deactivate(obj, &descr_type_test);
 887                 debug_object_activate(obj, &descr_type_test);
 888                 return true;
 889
 890         default:
 891                 return false;
 892         }
 893 }
 894
 895 /*
 896  * fixup_destroy is called when:
 897  * - an active object is destroyed
 898  */
 899 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 900 {
 901         struct self_test *obj = addr;
 902
 903         switch (state) {
 904         case ODEBUG_STATE_ACTIVE:
 905                 debug_object_deactivate(obj, &descr_type_test);
 906                 debug_object_destroy(obj, &descr_type_test);
 907                 return true;
 908         default:
 909                 return false;
 910         }
 911 }
 912
 913 /*
 914  * fixup_free is called when:
 915  * - an active object is freed
 916  */
 917 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 918 {
 919         struct self_test *obj = addr;
 920
 921         switch (state) {
 922         case ODEBUG_STATE_ACTIVE:
 923                 debug_object_deactivate(obj, &descr_type_test);
 924                 debug_object_free(obj, &descr_type_test);
 925                 return true;
 926         default:
 927                 return false;
 928         }
 929 }
 930
 931 static int __init
 932 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 933 {
 934         struct debug_bucket *db;
 935         struct debug_obj *obj;
 936         unsigned long flags;
 937         int res = -EINVAL;
 938
 939         db = get_bucket((unsigned long) addr);
 940
 941         raw_spin_lock_irqsave(&db->lock, flags);
 942
 943         obj = lookup_object(addr, db);
 944         if (!obj && state != ODEBUG_STATE_NONE) {
 945                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 946                 goto out;
 947         }
 948         if (obj && obj->state != state) {
 949                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 950                        obj->state, state);
 951                 goto out;
 952         }
 953         if (fixups != debug_objects_fixups) {
 954                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 955                        fixups, debug_objects_fixups);
 956                 goto out;
 957         }
 958         if (warnings != debug_objects_warnings) {
 959                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 960                        warnings, debug_objects_warnings);
 961                 goto out;
 962         }
 963         res = 0;
 964 out:
 965         raw_spin_unlock_irqrestore(&db->lock, flags);
 966         if (res)
 967                 debug_objects_enabled = 0;
 968         return res;
 969 }
 970
 971 static __initdata struct debug_obj_descr descr_type_test = {
 972         .name                   = "selftest",
 973         .is_static_object       = is_static_object,
 974         .fixup_init             = fixup_init,
 975         .fixup_activate         = fixup_activate,
 976         .fixup_destroy          = fixup_destroy,
 977         .fixup_free             = fixup_free,
 978 };
 979
 980 static __initdata struct self_test obj = { .static_init = 0 };
 981
 982 static void __init debug_objects_selftest(void)
 983 {
 984         int fixups, oldfixups, warnings, oldwarnings;
 985         unsigned long flags;
 986
 987         local_irq_save(flags);
 988
 989         fixups = oldfixups = debug_objects_fixups;
 990         warnings = oldwarnings = debug_objects_warnings;
 991         descr_test = &descr_type_test;
 992
 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_object_activate(&obj, &descr_type_test);
1000         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1001                 goto out;
1002         debug_object_deactivate(&obj, &descr_type_test);
1003         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1004                 goto out;
1005         debug_object_destroy(&obj, &descr_type_test);
1006         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1007                 goto out;
1008         debug_object_init(&obj, &descr_type_test);
1009         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1010                 goto out;
1011         debug_object_activate(&obj, &descr_type_test);
1012         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1013                 goto out;
1014         debug_object_deactivate(&obj, &descr_type_test);
1015         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1016                 goto out;
1017         debug_object_free(&obj, &descr_type_test);
1018         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1019                 goto out;
1020
1021         obj.static_init = 1;
1022         debug_object_activate(&obj, &descr_type_test);
1023         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1024                 goto out;
1025         debug_object_init(&obj, &descr_type_test);
1026         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1027                 goto out;
1028         debug_object_free(&obj, &descr_type_test);
1029         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1030                 goto out;
1031
1032 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1033         debug_object_init(&obj, &descr_type_test);
1034         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1035                 goto out;
1036         debug_object_activate(&obj, &descr_type_test);
1037         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1038                 goto out;
1039         __debug_check_no_obj_freed(&obj, sizeof(obj));
1040         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1041                 goto out;
1042 #endif
1043         pr_info("selftest passed\n");
1044
1045 out:
1046         debug_objects_fixups = oldfixups;
1047         debug_objects_warnings = oldwarnings;
1048         descr_test = NULL;
1049
1050         local_irq_restore(flags);
1051 }
1052 #else
1053 static inline void debug_objects_selftest(void) { }
1054 #endif
1055
1056 /*
1057  * Called during early boot to initialize the hash buckets and link
1058  * the static object pool objects into the poll list. After this call
1059  * the object tracker is fully operational.
1060  */
1061 void __init debug_objects_early_init(void)
1062 {
1063         int i;
1064
1065         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1066                 raw_spin_lock_init(&obj_hash[i].lock);
1067
1068         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1069                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1070 }
1071
1072 /*
1073  * Convert the statically allocated objects to dynamic ones:
1074  */
1075 static int __init debug_objects_replace_static_objects(void)
1076 {
1077         struct debug_bucket *db = obj_hash;
1078         struct hlist_node *tmp;
1079         struct debug_obj *obj, *new;
1080         HLIST_HEAD(objects);
1081         int i, cnt = 0;
1082
1083         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1084                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1085                 if (!obj)
1086                         goto free;
1087                 hlist_add_head(&obj->node, &objects);
1088         }
1089
1090         /*
1091          * When debug_objects_mem_init() is called we know that only
1092          * one CPU is up, so disabling interrupts is enough
1093          * protection. This avoids the lockdep hell of lock ordering.
1094          */
1095         local_irq_disable();
1096
1097         /* Remove the statically allocated objects from the pool */
1098         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1099                 hlist_del(&obj->node);
1100         /* Move the allocated objects to the pool */
1101         hlist_move_list(&objects, &obj_pool);
1102
1103         /* Replace the active object references */
1104         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1105                 hlist_move_list(&db->list, &objects);
1106
1107                 hlist_for_each_entry(obj, &objects, node) {
1108                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1109                         hlist_del(&new->node);
1110                         /* copy object data */
1111                         *new = *obj;
1112                         hlist_add_head(&new->node, &db->list);
1113                         cnt++;
1114                 }
1115         }
1116         local_irq_enable();
1117
1118         pr_debug("%d of %d active objects replaced\n",
1119                  cnt, obj_pool_used);
1120         return 0;
1121 free:
1122         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1123                 hlist_del(&obj->node);
1124                 kmem_cache_free(obj_cache, obj);
1125         }
1126         return -ENOMEM;
1127 }
1128
1129 /*
1130  * Called after the kmem_caches are functional to setup a dedicated
1131  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1132  * prevents that the debug code is called on kmem_cache_free() for the
1133  * debug tracker objects to avoid recursive calls.
1134  */
1135 void __init debug_objects_mem_init(void)
1136 {
1137         if (!debug_objects_enabled)
1138                 return;
1139
1140         obj_cache = kmem_cache_create("debug_objects_cache",
1141                                       sizeof (struct debug_obj), 0,
1142                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1143                                       NULL);
1144
1145         if (!obj_cache || debug_objects_replace_static_objects()) {
1146                 debug_objects_enabled = 0;
1147                 if (obj_cache)
1148                         kmem_cache_destroy(obj_cache);
1149                 pr_warn("out of memory.\n");
1150         } else
1151                 debug_objects_selftest();
1152
1153         /*
1154          * Increase the thresholds for allocating and freeing objects
1155          * according to the number of possible CPUs available in the system.
1156          */
1157         debug_objects_pool_size += num_possible_cpus() * 32;
1158         debug_objects_pool_min_level += num_possible_cpus() * 4;
1159 }