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 static HLIST_HEAD(obj_to_free);
  46
  47 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  48 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  49 static int                      obj_pool_used;
  50 static int                      obj_pool_max_used;
  51 /* The number of objs on the global free list */
  52 static int                      obj_nr_tofree;
  53 static struct kmem_cache        *obj_cache;
  54
  55 static int                      debug_objects_maxchain __read_mostly;
  56 static int                      debug_objects_maxchecked __read_mostly;
  57 static int                      debug_objects_fixups __read_mostly;
  58 static int                      debug_objects_warnings __read_mostly;
  59 static int                      debug_objects_enabled __read_mostly
  60                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  61 static int                      debug_objects_pool_size __read_mostly
  62                                 = ODEBUG_POOL_SIZE;
  63 static int                      debug_objects_pool_min_level __read_mostly
  64                                 = ODEBUG_POOL_MIN_LEVEL;
  65 static struct debug_obj_descr   *descr_test  __read_mostly;
  66
  67 /*
  68  * Track numbers of kmem_cache_alloc()/free() calls done.
  69  */
  70 static int                      debug_objects_allocated;
  71 static int                      debug_objects_freed;
  72
  73 static void free_obj_work(struct work_struct *work);
  74 static DECLARE_WORK(debug_obj_work, free_obj_work);
  75
  76 static int __init enable_object_debug(char *str)
  77 {
  78         debug_objects_enabled = 1;
  79         return 0;
  80 }
  81
  82 static int __init disable_object_debug(char *str)
  83 {
  84         debug_objects_enabled = 0;
  85         return 0;
  86 }
  87
  88 early_param("debug_objects", enable_object_debug);
  89 early_param("no_debug_objects", disable_object_debug);
  90
  91 static const char *obj_states[ODEBUG_STATE_MAX] = {
  92         [ODEBUG_STATE_NONE]             = "none",
  93         [ODEBUG_STATE_INIT]             = "initialized",
  94         [ODEBUG_STATE_INACTIVE]         = "inactive",
  95         [ODEBUG_STATE_ACTIVE]           = "active",
  96         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  97         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  98 };
  99
 100 static void fill_pool(void)
 101 {
 102         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
 103         struct debug_obj *new, *obj;
 104         unsigned long flags;
 105
 106         if (likely(obj_pool_free >= debug_objects_pool_min_level))
 107                 return;
 108
 109         /*
 110          * Reuse objs from the global free list; they will be reinitialized
 111          * when allocating.
 112          */
 113         while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 114                 raw_spin_lock_irqsave(&pool_lock, flags);
 115                 /*
 116                  * Recheck with the lock held as the worker thread might have
 117                  * won the race and freed the global free list already.
 118                  */
 119                 if (obj_nr_tofree) {
 120                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 121                         hlist_del(&obj->node);
 122                         obj_nr_tofree--;
 123                         hlist_add_head(&obj->node, &obj_pool);
 124                         obj_pool_free++;
 125                 }
 126                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 127         }
 128
 129         if (unlikely(!obj_cache))
 130                 return;
 131
 132         while (obj_pool_free < debug_objects_pool_min_level) {
 133
 134                 new = kmem_cache_zalloc(obj_cache, gfp);
 135                 if (!new)
 136                         return;
 137
 138                 kmemleak_ignore(new);
 139                 raw_spin_lock_irqsave(&pool_lock, flags);
 140                 hlist_add_head(&new->node, &obj_pool);
 141                 debug_objects_allocated++;
 142                 obj_pool_free++;
 143                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 144         }
 145 }
 146
 147 /*
 148  * Lookup an object in the hash bucket.
 149  */
 150 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 151 {
 152         struct debug_obj *obj;
 153         int cnt = 0;
 154
 155         hlist_for_each_entry(obj, &b->list, node) {
 156                 cnt++;
 157                 if (obj->object == addr)
 158                         return obj;
 159         }
 160         if (cnt > debug_objects_maxchain)
 161                 debug_objects_maxchain = cnt;
 162
 163         return NULL;
 164 }
 165
 166 /*
 167  * Allocate a new object. If the pool is empty, switch off the debugger.
 168  * Must be called with interrupts disabled.
 169  */
 170 static struct debug_obj *
 171 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 172 {
 173         struct debug_obj *obj = NULL;
 174
 175         raw_spin_lock(&pool_lock);
 176         if (obj_pool.first) {
 177                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 178
 179                 obj->object = addr;
 180                 obj->descr  = descr;
 181                 obj->state  = ODEBUG_STATE_NONE;
 182                 obj->astate = 0;
 183                 hlist_del(&obj->node);
 184
 185                 hlist_add_head(&obj->node, &b->list);
 186
 187                 obj_pool_used++;
 188                 if (obj_pool_used > obj_pool_max_used)
 189                         obj_pool_max_used = obj_pool_used;
 190
 191                 obj_pool_free--;
 192                 if (obj_pool_free < obj_pool_min_free)
 193                         obj_pool_min_free = obj_pool_free;
 194         }
 195         raw_spin_unlock(&pool_lock);
 196
 197         return obj;
 198 }
 199
 200 /*
 201  * workqueue function to free objects.
 202  *
 203  * To reduce contention on the global pool_lock, the actual freeing of
 204  * debug objects will be delayed if the pool_lock is busy.
 205  */
 206 static void free_obj_work(struct work_struct *work)
 207 {
 208         struct hlist_node *tmp;
 209         struct debug_obj *obj;
 210         unsigned long flags;
 211         HLIST_HEAD(tofree);
 212
 213         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 214                 return;
 215
 216         /*
 217          * The objs on the pool list might be allocated before the work is
 218          * run, so recheck if pool list it full or not, if not fill pool
 219          * list from the global free list
 220          */
 221         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 222                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 223                 hlist_del(&obj->node);
 224                 hlist_add_head(&obj->node, &obj_pool);
 225                 obj_pool_free++;
 226                 obj_nr_tofree--;
 227         }
 228
 229         /*
 230          * Pool list is already full and there are still objs on the free
 231          * list. Move remaining free objs to a temporary list to free the
 232          * memory outside the pool_lock held region.
 233          */
 234         if (obj_nr_tofree) {
 235                 hlist_move_list(&obj_to_free, &tofree);
 236                 obj_nr_tofree = 0;
 237         }
 238         raw_spin_unlock_irqrestore(&pool_lock, flags);
 239
 240         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 241                 hlist_del(&obj->node);
 242                 kmem_cache_free(obj_cache, obj);
 243         }
 244 }
 245
 246 static bool __free_object(struct debug_obj *obj)
 247 {
 248         unsigned long flags;
 249         bool work;
 250
 251         raw_spin_lock_irqsave(&pool_lock, flags);
 252         work = (obj_pool_free > debug_objects_pool_size) && obj_cache;
 253         obj_pool_used--;
 254
 255         if (work) {
 256                 obj_nr_tofree++;
 257                 hlist_add_head(&obj->node, &obj_to_free);
 258         } else {
 259                 obj_pool_free++;
 260                 hlist_add_head(&obj->node, &obj_pool);
 261         }
 262         raw_spin_unlock_irqrestore(&pool_lock, flags);
 263         return work;
 264 }
 265
 266 /*
 267  * Put the object back into the pool and schedule work to free objects
 268  * if necessary.
 269  */
 270 static void free_object(struct debug_obj *obj)
 271 {
 272         if (__free_object(obj))
 273                 schedule_work(&debug_obj_work);
 274 }
 275
 276 /*
 277  * We run out of memory. That means we probably have tons of objects
 278  * allocated.
 279  */
 280 static void debug_objects_oom(void)
 281 {
 282         struct debug_bucket *db = obj_hash;
 283         struct hlist_node *tmp;
 284         HLIST_HEAD(freelist);
 285         struct debug_obj *obj;
 286         unsigned long flags;
 287         int i;
 288
 289         pr_warn("Out of memory. ODEBUG disabled\n");
 290
 291         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 292                 raw_spin_lock_irqsave(&db->lock, flags);
 293                 hlist_move_list(&db->list, &freelist);
 294                 raw_spin_unlock_irqrestore(&db->lock, flags);
 295
 296                 /* Now free them */
 297                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 298                         hlist_del(&obj->node);
 299                         free_object(obj);
 300                 }
 301         }
 302 }
 303
 304 /*
 305  * We use the pfn of the address for the hash. That way we can check
 306  * for freed objects simply by checking the affected bucket.
 307  */
 308 static struct debug_bucket *get_bucket(unsigned long addr)
 309 {
 310         unsigned long hash;
 311
 312         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 313         return &obj_hash[hash];
 314 }
 315
 316 static void debug_print_object(struct debug_obj *obj, char *msg)
 317 {
 318         struct debug_obj_descr *descr = obj->descr;
 319         static int limit;
 320
 321         if (limit < 5 && descr != descr_test) {
 322                 void *hint = descr->debug_hint ?
 323                         descr->debug_hint(obj->object) : NULL;
 324                 limit++;
 325                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 326                                  "object type: %s hint: %pS\n",
 327                         msg, obj_states[obj->state], obj->astate,
 328                         descr->name, hint);
 329         }
 330         debug_objects_warnings++;
 331 }
 332
 333 /*
 334  * Try to repair the damage, so we have a better chance to get useful
 335  * debug output.
 336  */
 337 static bool
 338 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 339                    void * addr, enum debug_obj_state state)
 340 {
 341         if (fixup && fixup(addr, state)) {
 342                 debug_objects_fixups++;
 343                 return true;
 344         }
 345         return false;
 346 }
 347
 348 static void debug_object_is_on_stack(void *addr, int onstack)
 349 {
 350         int is_on_stack;
 351         static int limit;
 352
 353         if (limit > 4)
 354                 return;
 355
 356         is_on_stack = object_is_on_stack(addr);
 357         if (is_on_stack == onstack)
 358                 return;
 359
 360         limit++;
 361         if (is_on_stack)
 362                 pr_warn("object is on stack, but not annotated\n");
 363         else
 364                 pr_warn("object is not on stack, but annotated\n");
 365         WARN_ON(1);
 366 }
 367
 368 static void
 369 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 370 {
 371         enum debug_obj_state state;
 372         struct debug_bucket *db;
 373         struct debug_obj *obj;
 374         unsigned long flags;
 375
 376         fill_pool();
 377
 378         db = get_bucket((unsigned long) addr);
 379
 380         raw_spin_lock_irqsave(&db->lock, flags);
 381
 382         obj = lookup_object(addr, db);
 383         if (!obj) {
 384                 obj = alloc_object(addr, db, descr);
 385                 if (!obj) {
 386                         debug_objects_enabled = 0;
 387                         raw_spin_unlock_irqrestore(&db->lock, flags);
 388                         debug_objects_oom();
 389                         return;
 390                 }
 391                 debug_object_is_on_stack(addr, onstack);
 392         }
 393
 394         switch (obj->state) {
 395         case ODEBUG_STATE_NONE:
 396         case ODEBUG_STATE_INIT:
 397         case ODEBUG_STATE_INACTIVE:
 398                 obj->state = ODEBUG_STATE_INIT;
 399                 break;
 400
 401         case ODEBUG_STATE_ACTIVE:
 402                 debug_print_object(obj, "init");
 403                 state = obj->state;
 404                 raw_spin_unlock_irqrestore(&db->lock, flags);
 405                 debug_object_fixup(descr->fixup_init, addr, state);
 406                 return;
 407
 408         case ODEBUG_STATE_DESTROYED:
 409                 debug_print_object(obj, "init");
 410                 break;
 411         default:
 412                 break;
 413         }
 414
 415         raw_spin_unlock_irqrestore(&db->lock, flags);
 416 }
 417
 418 /**
 419  * debug_object_init - debug checks when an object is initialized
 420  * @addr:       address of the object
 421  * @descr:      pointer to an object specific debug description structure
 422  */
 423 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 424 {
 425         if (!debug_objects_enabled)
 426                 return;
 427
 428         __debug_object_init(addr, descr, 0);
 429 }
 430 EXPORT_SYMBOL_GPL(debug_object_init);
 431
 432 /**
 433  * debug_object_init_on_stack - debug checks when an object on stack is
 434  *                              initialized
 435  * @addr:       address of the object
 436  * @descr:      pointer to an object specific debug description structure
 437  */
 438 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 439 {
 440         if (!debug_objects_enabled)
 441                 return;
 442
 443         __debug_object_init(addr, descr, 1);
 444 }
 445 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 446
 447 /**
 448  * debug_object_activate - debug checks when an object is activated
 449  * @addr:       address of the object
 450  * @descr:      pointer to an object specific debug description structure
 451  * Returns 0 for success, -EINVAL for check failed.
 452  */
 453 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 454 {
 455         enum debug_obj_state state;
 456         struct debug_bucket *db;
 457         struct debug_obj *obj;
 458         unsigned long flags;
 459         int ret;
 460         struct debug_obj o = { .object = addr,
 461                                .state = ODEBUG_STATE_NOTAVAILABLE,
 462                                .descr = descr };
 463
 464         if (!debug_objects_enabled)
 465                 return 0;
 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                         obj->state = ODEBUG_STATE_ACTIVE;
 477                         ret = 0;
 478                         break;
 479
 480                 case ODEBUG_STATE_ACTIVE:
 481                         debug_print_object(obj, "activate");
 482                         state = obj->state;
 483                         raw_spin_unlock_irqrestore(&db->lock, flags);
 484                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 485                         return ret ? 0 : -EINVAL;
 486
 487                 case ODEBUG_STATE_DESTROYED:
 488                         debug_print_object(obj, "activate");
 489                         ret = -EINVAL;
 490                         break;
 491                 default:
 492                         ret = 0;
 493                         break;
 494                 }
 495                 raw_spin_unlock_irqrestore(&db->lock, flags);
 496                 return ret;
 497         }
 498
 499         raw_spin_unlock_irqrestore(&db->lock, flags);
 500         /*
 501          * We are here when a static object is activated. We
 502          * let the type specific code confirm whether this is
 503          * true or not. if true, we just make sure that the
 504          * static object is tracked in the object tracker. If
 505          * not, this must be a bug, so we try to fix it up.
 506          */
 507         if (descr->is_static_object && descr->is_static_object(addr)) {
 508                 /* track this static object */
 509                 debug_object_init(addr, descr);
 510                 debug_object_activate(addr, descr);
 511         } else {
 512                 debug_print_object(&o, "activate");
 513                 ret = debug_object_fixup(descr->fixup_activate, addr,
 514                                         ODEBUG_STATE_NOTAVAILABLE);
 515                 return ret ? 0 : -EINVAL;
 516         }
 517         return 0;
 518 }
 519 EXPORT_SYMBOL_GPL(debug_object_activate);
 520
 521 /**
 522  * debug_object_deactivate - debug checks when an object is deactivated
 523  * @addr:       address of the object
 524  * @descr:      pointer to an object specific debug description structure
 525  */
 526 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 527 {
 528         struct debug_bucket *db;
 529         struct debug_obj *obj;
 530         unsigned long flags;
 531
 532         if (!debug_objects_enabled)
 533                 return;
 534
 535         db = get_bucket((unsigned long) addr);
 536
 537         raw_spin_lock_irqsave(&db->lock, flags);
 538
 539         obj = lookup_object(addr, db);
 540         if (obj) {
 541                 switch (obj->state) {
 542                 case ODEBUG_STATE_INIT:
 543                 case ODEBUG_STATE_INACTIVE:
 544                 case ODEBUG_STATE_ACTIVE:
 545                         if (!obj->astate)
 546                                 obj->state = ODEBUG_STATE_INACTIVE;
 547                         else
 548                                 debug_print_object(obj, "deactivate");
 549                         break;
 550
 551                 case ODEBUG_STATE_DESTROYED:
 552                         debug_print_object(obj, "deactivate");
 553                         break;
 554                 default:
 555                         break;
 556                 }
 557         } else {
 558                 struct debug_obj o = { .object = addr,
 559                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 560                                        .descr = descr };
 561
 562                 debug_print_object(&o, "deactivate");
 563         }
 564
 565         raw_spin_unlock_irqrestore(&db->lock, flags);
 566 }
 567 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 568
 569 /**
 570  * debug_object_destroy - debug checks when an object is destroyed
 571  * @addr:       address of the object
 572  * @descr:      pointer to an object specific debug description structure
 573  */
 574 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 575 {
 576         enum debug_obj_state state;
 577         struct debug_bucket *db;
 578         struct debug_obj *obj;
 579         unsigned long flags;
 580
 581         if (!debug_objects_enabled)
 582                 return;
 583
 584         db = get_bucket((unsigned long) addr);
 585
 586         raw_spin_lock_irqsave(&db->lock, flags);
 587
 588         obj = lookup_object(addr, db);
 589         if (!obj)
 590                 goto out_unlock;
 591
 592         switch (obj->state) {
 593         case ODEBUG_STATE_NONE:
 594         case ODEBUG_STATE_INIT:
 595         case ODEBUG_STATE_INACTIVE:
 596                 obj->state = ODEBUG_STATE_DESTROYED;
 597                 break;
 598         case ODEBUG_STATE_ACTIVE:
 599                 debug_print_object(obj, "destroy");
 600                 state = obj->state;
 601                 raw_spin_unlock_irqrestore(&db->lock, flags);
 602                 debug_object_fixup(descr->fixup_destroy, addr, state);
 603                 return;
 604
 605         case ODEBUG_STATE_DESTROYED:
 606                 debug_print_object(obj, "destroy");
 607                 break;
 608         default:
 609                 break;
 610         }
 611 out_unlock:
 612         raw_spin_unlock_irqrestore(&db->lock, flags);
 613 }
 614 EXPORT_SYMBOL_GPL(debug_object_destroy);
 615
 616 /**
 617  * debug_object_free - debug checks when an object is freed
 618  * @addr:       address of the object
 619  * @descr:      pointer to an object specific debug description structure
 620  */
 621 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 622 {
 623         enum debug_obj_state state;
 624         struct debug_bucket *db;
 625         struct debug_obj *obj;
 626         unsigned long flags;
 627
 628         if (!debug_objects_enabled)
 629                 return;
 630
 631         db = get_bucket((unsigned long) addr);
 632
 633         raw_spin_lock_irqsave(&db->lock, flags);
 634
 635         obj = lookup_object(addr, db);
 636         if (!obj)
 637                 goto out_unlock;
 638
 639         switch (obj->state) {
 640         case ODEBUG_STATE_ACTIVE:
 641                 debug_print_object(obj, "free");
 642                 state = obj->state;
 643                 raw_spin_unlock_irqrestore(&db->lock, flags);
 644                 debug_object_fixup(descr->fixup_free, addr, state);
 645                 return;
 646         default:
 647                 hlist_del(&obj->node);
 648                 raw_spin_unlock_irqrestore(&db->lock, flags);
 649                 free_object(obj);
 650                 return;
 651         }
 652 out_unlock:
 653         raw_spin_unlock_irqrestore(&db->lock, flags);
 654 }
 655 EXPORT_SYMBOL_GPL(debug_object_free);
 656
 657 /**
 658  * debug_object_assert_init - debug checks when object should be init-ed
 659  * @addr:       address of the object
 660  * @descr:      pointer to an object specific debug description structure
 661  */
 662 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 663 {
 664         struct debug_bucket *db;
 665         struct debug_obj *obj;
 666         unsigned long flags;
 667
 668         if (!debug_objects_enabled)
 669                 return;
 670
 671         db = get_bucket((unsigned long) addr);
 672
 673         raw_spin_lock_irqsave(&db->lock, flags);
 674
 675         obj = lookup_object(addr, db);
 676         if (!obj) {
 677                 struct debug_obj o = { .object = addr,
 678                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 679                                        .descr = descr };
 680
 681                 raw_spin_unlock_irqrestore(&db->lock, flags);
 682                 /*
 683                  * Maybe the object is static, and we let the type specific
 684                  * code confirm. Track this static object if true, else invoke
 685                  * fixup.
 686                  */
 687                 if (descr->is_static_object && descr->is_static_object(addr)) {
 688                         /* Track this static object */
 689                         debug_object_init(addr, descr);
 690                 } else {
 691                         debug_print_object(&o, "assert_init");
 692                         debug_object_fixup(descr->fixup_assert_init, addr,
 693                                            ODEBUG_STATE_NOTAVAILABLE);
 694                 }
 695                 return;
 696         }
 697
 698         raw_spin_unlock_irqrestore(&db->lock, flags);
 699 }
 700 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 701
 702 /**
 703  * debug_object_active_state - debug checks object usage state machine
 704  * @addr:       address of the object
 705  * @descr:      pointer to an object specific debug description structure
 706  * @expect:     expected state
 707  * @next:       state to move to if expected state is found
 708  */
 709 void
 710 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 711                           unsigned int expect, unsigned int next)
 712 {
 713         struct debug_bucket *db;
 714         struct debug_obj *obj;
 715         unsigned long flags;
 716
 717         if (!debug_objects_enabled)
 718                 return;
 719
 720         db = get_bucket((unsigned long) addr);
 721
 722         raw_spin_lock_irqsave(&db->lock, flags);
 723
 724         obj = lookup_object(addr, db);
 725         if (obj) {
 726                 switch (obj->state) {
 727                 case ODEBUG_STATE_ACTIVE:
 728                         if (obj->astate == expect)
 729                                 obj->astate = next;
 730                         else
 731                                 debug_print_object(obj, "active_state");
 732                         break;
 733
 734                 default:
 735                         debug_print_object(obj, "active_state");
 736                         break;
 737                 }
 738         } else {
 739                 struct debug_obj o = { .object = addr,
 740                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 741                                        .descr = descr };
 742
 743                 debug_print_object(&o, "active_state");
 744         }
 745
 746         raw_spin_unlock_irqrestore(&db->lock, flags);
 747 }
 748 EXPORT_SYMBOL_GPL(debug_object_active_state);
 749
 750 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 751 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 752 {
 753         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 754         struct debug_obj_descr *descr;
 755         enum debug_obj_state state;
 756         struct debug_bucket *db;
 757         struct hlist_node *tmp;
 758         struct debug_obj *obj;
 759         int cnt, objs_checked = 0;
 760         bool work = false;
 761
 762         saddr = (unsigned long) address;
 763         eaddr = saddr + size;
 764         paddr = saddr & ODEBUG_CHUNK_MASK;
 765         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 766         chunks >>= ODEBUG_CHUNK_SHIFT;
 767
 768         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 769                 db = get_bucket(paddr);
 770
 771 repeat:
 772                 cnt = 0;
 773                 raw_spin_lock_irqsave(&db->lock, flags);
 774                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 775                         cnt++;
 776                         oaddr = (unsigned long) obj->object;
 777                         if (oaddr < saddr || oaddr >= eaddr)
 778                                 continue;
 779
 780                         switch (obj->state) {
 781                         case ODEBUG_STATE_ACTIVE:
 782                                 debug_print_object(obj, "free");
 783                                 descr = obj->descr;
 784                                 state = obj->state;
 785                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 786                                 debug_object_fixup(descr->fixup_free,
 787                                                    (void *) oaddr, state);
 788                                 goto repeat;
 789                         default:
 790                                 hlist_del(&obj->node);
 791                                 work |= __free_object(obj);
 792                                 break;
 793                         }
 794                 }
 795                 raw_spin_unlock_irqrestore(&db->lock, flags);
 796
 797                 if (cnt > debug_objects_maxchain)
 798                         debug_objects_maxchain = cnt;
 799
 800                 objs_checked += cnt;
 801         }
 802
 803         if (objs_checked > debug_objects_maxchecked)
 804                 debug_objects_maxchecked = objs_checked;
 805
 806         /* Schedule work to actually kmem_cache_free() objects */
 807         if (work)
 808                 schedule_work(&debug_obj_work);
 809 }
 810
 811 void debug_check_no_obj_freed(const void *address, unsigned long size)
 812 {
 813         if (debug_objects_enabled)
 814                 __debug_check_no_obj_freed(address, size);
 815 }
 816 #endif
 817
 818 #ifdef CONFIG_DEBUG_FS
 819
 820 static int debug_stats_show(struct seq_file *m, void *v)
 821 {
 822         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 823         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
 824         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 825         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 826         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 827         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 828         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 829         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 830         seq_printf(m, "on_free_list  :%d\n", obj_nr_tofree);
 831         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 832         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 833         return 0;
 834 }
 835
 836 static int debug_stats_open(struct inode *inode, struct file *filp)
 837 {
 838         return single_open(filp, debug_stats_show, NULL);
 839 }
 840
 841 static const struct file_operations debug_stats_fops = {
 842         .open           = debug_stats_open,
 843         .read           = seq_read,
 844         .llseek         = seq_lseek,
 845         .release        = single_release,
 846 };
 847
 848 static int __init debug_objects_init_debugfs(void)
 849 {
 850         struct dentry *dbgdir, *dbgstats;
 851
 852         if (!debug_objects_enabled)
 853                 return 0;
 854
 855         dbgdir = debugfs_create_dir("debug_objects", NULL);
 856         if (!dbgdir)
 857                 return -ENOMEM;
 858
 859         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 860                                        &debug_stats_fops);
 861         if (!dbgstats)
 862                 goto err;
 863
 864         return 0;
 865
 866 err:
 867         debugfs_remove(dbgdir);
 868
 869         return -ENOMEM;
 870 }
 871 __initcall(debug_objects_init_debugfs);
 872
 873 #else
 874 static inline void debug_objects_init_debugfs(void) { }
 875 #endif
 876
 877 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 878
 879 /* Random data structure for the self test */
 880 struct self_test {
 881         unsigned long   dummy1[6];
 882         int             static_init;
 883         unsigned long   dummy2[3];
 884 };
 885
 886 static __initdata struct debug_obj_descr descr_type_test;
 887
 888 static bool __init is_static_object(void *addr)
 889 {
 890         struct self_test *obj = addr;
 891
 892         return obj->static_init;
 893 }
 894
 895 /*
 896  * fixup_init is called when:
 897  * - an active object is initialized
 898  */
 899 static bool __init fixup_init(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_init(obj, &descr_type_test);
 907                 return true;
 908         default:
 909                 return false;
 910         }
 911 }
 912
 913 /*
 914  * fixup_activate is called when:
 915  * - an active object is activated
 916  * - an unknown non-static object is activated
 917  */
 918 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 919 {
 920         struct self_test *obj = addr;
 921
 922         switch (state) {
 923         case ODEBUG_STATE_NOTAVAILABLE:
 924                 return true;
 925         case ODEBUG_STATE_ACTIVE:
 926                 debug_object_deactivate(obj, &descr_type_test);
 927                 debug_object_activate(obj, &descr_type_test);
 928                 return true;
 929
 930         default:
 931                 return false;
 932         }
 933 }
 934
 935 /*
 936  * fixup_destroy is called when:
 937  * - an active object is destroyed
 938  */
 939 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 940 {
 941         struct self_test *obj = addr;
 942
 943         switch (state) {
 944         case ODEBUG_STATE_ACTIVE:
 945                 debug_object_deactivate(obj, &descr_type_test);
 946                 debug_object_destroy(obj, &descr_type_test);
 947                 return true;
 948         default:
 949                 return false;
 950         }
 951 }
 952
 953 /*
 954  * fixup_free is called when:
 955  * - an active object is freed
 956  */
 957 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 958 {
 959         struct self_test *obj = addr;
 960
 961         switch (state) {
 962         case ODEBUG_STATE_ACTIVE:
 963                 debug_object_deactivate(obj, &descr_type_test);
 964                 debug_object_free(obj, &descr_type_test);
 965                 return true;
 966         default:
 967                 return false;
 968         }
 969 }
 970
 971 static int __init
 972 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 973 {
 974         struct debug_bucket *db;
 975         struct debug_obj *obj;
 976         unsigned long flags;
 977         int res = -EINVAL;
 978
 979         db = get_bucket((unsigned long) addr);
 980
 981         raw_spin_lock_irqsave(&db->lock, flags);
 982
 983         obj = lookup_object(addr, db);
 984         if (!obj && state != ODEBUG_STATE_NONE) {
 985                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 986                 goto out;
 987         }
 988         if (obj && obj->state != state) {
 989                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 990                        obj->state, state);
 991                 goto out;
 992         }
 993         if (fixups != debug_objects_fixups) {
 994                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 995                        fixups, debug_objects_fixups);
 996                 goto out;
 997         }
 998         if (warnings != debug_objects_warnings) {
 999                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1000                        warnings, debug_objects_warnings);
1001                 goto out;
1002         }
1003         res = 0;
1004 out:
1005         raw_spin_unlock_irqrestore(&db->lock, flags);
1006         if (res)
1007                 debug_objects_enabled = 0;
1008         return res;
1009 }
1010
1011 static __initdata struct debug_obj_descr descr_type_test = {
1012         .name                   = "selftest",
1013         .is_static_object       = is_static_object,
1014         .fixup_init             = fixup_init,
1015         .fixup_activate         = fixup_activate,
1016         .fixup_destroy          = fixup_destroy,
1017         .fixup_free             = fixup_free,
1018 };
1019
1020 static __initdata struct self_test obj = { .static_init = 0 };
1021
1022 static void __init debug_objects_selftest(void)
1023 {
1024         int fixups, oldfixups, warnings, oldwarnings;
1025         unsigned long flags;
1026
1027         local_irq_save(flags);
1028
1029         fixups = oldfixups = debug_objects_fixups;
1030         warnings = oldwarnings = debug_objects_warnings;
1031         descr_test = &descr_type_test;
1032
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_object_activate(&obj, &descr_type_test);
1040         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1041                 goto out;
1042         debug_object_deactivate(&obj, &descr_type_test);
1043         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1044                 goto out;
1045         debug_object_destroy(&obj, &descr_type_test);
1046         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1047                 goto out;
1048         debug_object_init(&obj, &descr_type_test);
1049         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1050                 goto out;
1051         debug_object_activate(&obj, &descr_type_test);
1052         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1053                 goto out;
1054         debug_object_deactivate(&obj, &descr_type_test);
1055         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1056                 goto out;
1057         debug_object_free(&obj, &descr_type_test);
1058         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1059                 goto out;
1060
1061         obj.static_init = 1;
1062         debug_object_activate(&obj, &descr_type_test);
1063         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1064                 goto out;
1065         debug_object_init(&obj, &descr_type_test);
1066         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1067                 goto out;
1068         debug_object_free(&obj, &descr_type_test);
1069         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1070                 goto out;
1071
1072 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1073         debug_object_init(&obj, &descr_type_test);
1074         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1075                 goto out;
1076         debug_object_activate(&obj, &descr_type_test);
1077         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1078                 goto out;
1079         __debug_check_no_obj_freed(&obj, sizeof(obj));
1080         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1081                 goto out;
1082 #endif
1083         pr_info("selftest passed\n");
1084
1085 out:
1086         debug_objects_fixups = oldfixups;
1087         debug_objects_warnings = oldwarnings;
1088         descr_test = NULL;
1089
1090         local_irq_restore(flags);
1091 }
1092 #else
1093 static inline void debug_objects_selftest(void) { }
1094 #endif
1095
1096 /*
1097  * Called during early boot to initialize the hash buckets and link
1098  * the static object pool objects into the poll list. After this call
1099  * the object tracker is fully operational.
1100  */
1101 void __init debug_objects_early_init(void)
1102 {
1103         int i;
1104
1105         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1106                 raw_spin_lock_init(&obj_hash[i].lock);
1107
1108         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1109                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1110 }
1111
1112 /*
1113  * Convert the statically allocated objects to dynamic ones:
1114  */
1115 static int __init debug_objects_replace_static_objects(void)
1116 {
1117         struct debug_bucket *db = obj_hash;
1118         struct hlist_node *tmp;
1119         struct debug_obj *obj, *new;
1120         HLIST_HEAD(objects);
1121         int i, cnt = 0;
1122
1123         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1124                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1125                 if (!obj)
1126                         goto free;
1127                 kmemleak_ignore(obj);
1128                 hlist_add_head(&obj->node, &objects);
1129         }
1130
1131         /*
1132          * When debug_objects_mem_init() is called we know that only
1133          * one CPU is up, so disabling interrupts is enough
1134          * protection. This avoids the lockdep hell of lock ordering.
1135          */
1136         local_irq_disable();
1137
1138         /* Remove the statically allocated objects from the pool */
1139         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1140                 hlist_del(&obj->node);
1141         /* Move the allocated objects to the pool */
1142         hlist_move_list(&objects, &obj_pool);
1143
1144         /* Replace the active object references */
1145         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1146                 hlist_move_list(&db->list, &objects);
1147
1148                 hlist_for_each_entry(obj, &objects, node) {
1149                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1150                         hlist_del(&new->node);
1151                         /* copy object data */
1152                         *new = *obj;
1153                         hlist_add_head(&new->node, &db->list);
1154                         cnt++;
1155                 }
1156         }
1157         local_irq_enable();
1158
1159         pr_debug("%d of %d active objects replaced\n",
1160                  cnt, obj_pool_used);
1161         return 0;
1162 free:
1163         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1164                 hlist_del(&obj->node);
1165                 kmem_cache_free(obj_cache, obj);
1166         }
1167         return -ENOMEM;
1168 }
1169
1170 /*
1171  * Called after the kmem_caches are functional to setup a dedicated
1172  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1173  * prevents that the debug code is called on kmem_cache_free() for the
1174  * debug tracker objects to avoid recursive calls.
1175  */
1176 void __init debug_objects_mem_init(void)
1177 {
1178         if (!debug_objects_enabled)
1179                 return;
1180
1181         obj_cache = kmem_cache_create("debug_objects_cache",
1182                                       sizeof (struct debug_obj), 0,
1183                                       SLAB_DEBUG_OBJECTS, NULL);
1184
1185         if (!obj_cache || debug_objects_replace_static_objects()) {
1186                 debug_objects_enabled = 0;
1187                 if (obj_cache)
1188                         kmem_cache_destroy(obj_cache);
1189                 pr_warn("out of memory.\n");
1190         } else
1191                 debug_objects_selftest();
1192
1193         /*
1194          * Increase the thresholds for allocating and freeing objects
1195          * according to the number of possible CPUs available in the system.
1196          */
1197         debug_objects_pool_size += num_possible_cpus() * 32;
1198         debug_objects_pool_min_level += num_possible_cpus() * 4;
1199 }