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 __maybe_unused       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                 debug_objects_freed += obj_nr_tofree;
 237                 obj_nr_tofree = 0;
 238         }
 239         raw_spin_unlock_irqrestore(&pool_lock, flags);
 240
 241         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 242                 hlist_del(&obj->node);
 243                 kmem_cache_free(obj_cache, obj);
 244         }
 245 }
 246
 247 static bool __free_object(struct debug_obj *obj)
 248 {
 249         unsigned long flags;
 250         bool work;
 251
 252         raw_spin_lock_irqsave(&pool_lock, flags);
 253         work = (obj_pool_free > debug_objects_pool_size) && obj_cache;
 254         obj_pool_used--;
 255
 256         if (work) {
 257                 obj_nr_tofree++;
 258                 hlist_add_head(&obj->node, &obj_to_free);
 259         } else {
 260                 obj_pool_free++;
 261                 hlist_add_head(&obj->node, &obj_pool);
 262         }
 263         raw_spin_unlock_irqrestore(&pool_lock, flags);
 264         return work;
 265 }
 266
 267 /*
 268  * Put the object back into the pool and schedule work to free objects
 269  * if necessary.
 270  */
 271 static void free_object(struct debug_obj *obj)
 272 {
 273         if (__free_object(obj))
 274                 schedule_work(&debug_obj_work);
 275 }
 276
 277 /*
 278  * We run out of memory. That means we probably have tons of objects
 279  * allocated.
 280  */
 281 static void debug_objects_oom(void)
 282 {
 283         struct debug_bucket *db = obj_hash;
 284         struct hlist_node *tmp;
 285         HLIST_HEAD(freelist);
 286         struct debug_obj *obj;
 287         unsigned long flags;
 288         int i;
 289
 290         pr_warn("Out of memory. ODEBUG disabled\n");
 291
 292         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 293                 raw_spin_lock_irqsave(&db->lock, flags);
 294                 hlist_move_list(&db->list, &freelist);
 295                 raw_spin_unlock_irqrestore(&db->lock, flags);
 296
 297                 /* Now free them */
 298                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 299                         hlist_del(&obj->node);
 300                         free_object(obj);
 301                 }
 302         }
 303 }
 304
 305 /*
 306  * We use the pfn of the address for the hash. That way we can check
 307  * for freed objects simply by checking the affected bucket.
 308  */
 309 static struct debug_bucket *get_bucket(unsigned long addr)
 310 {
 311         unsigned long hash;
 312
 313         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 314         return &obj_hash[hash];
 315 }
 316
 317 static void debug_print_object(struct debug_obj *obj, char *msg)
 318 {
 319         struct debug_obj_descr *descr = obj->descr;
 320         static int limit;
 321
 322         if (limit < 5 && descr != descr_test) {
 323                 void *hint = descr->debug_hint ?
 324                         descr->debug_hint(obj->object) : NULL;
 325                 limit++;
 326                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 327                                  "object type: %s hint: %pS\n",
 328                         msg, obj_states[obj->state], obj->astate,
 329                         descr->name, hint);
 330         }
 331         debug_objects_warnings++;
 332 }
 333
 334 /*
 335  * Try to repair the damage, so we have a better chance to get useful
 336  * debug output.
 337  */
 338 static bool
 339 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 340                    void * addr, enum debug_obj_state state)
 341 {
 342         if (fixup && fixup(addr, state)) {
 343                 debug_objects_fixups++;
 344                 return true;
 345         }
 346         return false;
 347 }
 348
 349 static void debug_object_is_on_stack(void *addr, int onstack)
 350 {
 351         int is_on_stack;
 352         static int limit;
 353
 354         if (limit > 4)
 355                 return;
 356
 357         is_on_stack = object_is_on_stack(addr);
 358         if (is_on_stack == onstack)
 359                 return;
 360
 361         limit++;
 362         if (is_on_stack)
 363                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 364                          task_stack_page(current));
 365         else
 366                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 367                          task_stack_page(current));
 368
 369         WARN_ON(1);
 370 }
 371
 372 static void
 373 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 374 {
 375         enum debug_obj_state state;
 376         struct debug_bucket *db;
 377         struct debug_obj *obj;
 378         unsigned long flags;
 379
 380         fill_pool();
 381
 382         db = get_bucket((unsigned long) addr);
 383
 384         raw_spin_lock_irqsave(&db->lock, flags);
 385
 386         obj = lookup_object(addr, db);
 387         if (!obj) {
 388                 obj = alloc_object(addr, db, descr);
 389                 if (!obj) {
 390                         debug_objects_enabled = 0;
 391                         raw_spin_unlock_irqrestore(&db->lock, flags);
 392                         debug_objects_oom();
 393                         return;
 394                 }
 395                 debug_object_is_on_stack(addr, onstack);
 396         }
 397
 398         switch (obj->state) {
 399         case ODEBUG_STATE_NONE:
 400         case ODEBUG_STATE_INIT:
 401         case ODEBUG_STATE_INACTIVE:
 402                 obj->state = ODEBUG_STATE_INIT;
 403                 break;
 404
 405         case ODEBUG_STATE_ACTIVE:
 406                 debug_print_object(obj, "init");
 407                 state = obj->state;
 408                 raw_spin_unlock_irqrestore(&db->lock, flags);
 409                 debug_object_fixup(descr->fixup_init, addr, state);
 410                 return;
 411
 412         case ODEBUG_STATE_DESTROYED:
 413                 debug_print_object(obj, "init");
 414                 break;
 415         default:
 416                 break;
 417         }
 418
 419         raw_spin_unlock_irqrestore(&db->lock, flags);
 420 }
 421
 422 /**
 423  * debug_object_init - debug checks when an object is initialized
 424  * @addr:       address of the object
 425  * @descr:      pointer to an object specific debug description structure
 426  */
 427 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 428 {
 429         if (!debug_objects_enabled)
 430                 return;
 431
 432         __debug_object_init(addr, descr, 0);
 433 }
 434 EXPORT_SYMBOL_GPL(debug_object_init);
 435
 436 /**
 437  * debug_object_init_on_stack - debug checks when an object on stack is
 438  *                              initialized
 439  * @addr:       address of the object
 440  * @descr:      pointer to an object specific debug description structure
 441  */
 442 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 443 {
 444         if (!debug_objects_enabled)
 445                 return;
 446
 447         __debug_object_init(addr, descr, 1);
 448 }
 449 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 450
 451 /**
 452  * debug_object_activate - debug checks when an object is activated
 453  * @addr:       address of the object
 454  * @descr:      pointer to an object specific debug description structure
 455  * Returns 0 for success, -EINVAL for check failed.
 456  */
 457 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 458 {
 459         enum debug_obj_state state;
 460         struct debug_bucket *db;
 461         struct debug_obj *obj;
 462         unsigned long flags;
 463         int ret;
 464         struct debug_obj o = { .object = addr,
 465                                .state = ODEBUG_STATE_NOTAVAILABLE,
 466                                .descr = descr };
 467
 468         if (!debug_objects_enabled)
 469                 return 0;
 470
 471         db = get_bucket((unsigned long) addr);
 472
 473         raw_spin_lock_irqsave(&db->lock, flags);
 474
 475         obj = lookup_object(addr, db);
 476         if (obj) {
 477                 switch (obj->state) {
 478                 case ODEBUG_STATE_INIT:
 479                 case ODEBUG_STATE_INACTIVE:
 480                         obj->state = ODEBUG_STATE_ACTIVE;
 481                         ret = 0;
 482                         break;
 483
 484                 case ODEBUG_STATE_ACTIVE:
 485                         debug_print_object(obj, "activate");
 486                         state = obj->state;
 487                         raw_spin_unlock_irqrestore(&db->lock, flags);
 488                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 489                         return ret ? 0 : -EINVAL;
 490
 491                 case ODEBUG_STATE_DESTROYED:
 492                         debug_print_object(obj, "activate");
 493                         ret = -EINVAL;
 494                         break;
 495                 default:
 496                         ret = 0;
 497                         break;
 498                 }
 499                 raw_spin_unlock_irqrestore(&db->lock, flags);
 500                 return ret;
 501         }
 502
 503         raw_spin_unlock_irqrestore(&db->lock, flags);
 504         /*
 505          * We are here when a static object is activated. We
 506          * let the type specific code confirm whether this is
 507          * true or not. if true, we just make sure that the
 508          * static object is tracked in the object tracker. If
 509          * not, this must be a bug, so we try to fix it up.
 510          */
 511         if (descr->is_static_object && descr->is_static_object(addr)) {
 512                 /* track this static object */
 513                 debug_object_init(addr, descr);
 514                 debug_object_activate(addr, descr);
 515         } else {
 516                 debug_print_object(&o, "activate");
 517                 ret = debug_object_fixup(descr->fixup_activate, addr,
 518                                         ODEBUG_STATE_NOTAVAILABLE);
 519                 return ret ? 0 : -EINVAL;
 520         }
 521         return 0;
 522 }
 523 EXPORT_SYMBOL_GPL(debug_object_activate);
 524
 525 /**
 526  * debug_object_deactivate - debug checks when an object is deactivated
 527  * @addr:       address of the object
 528  * @descr:      pointer to an object specific debug description structure
 529  */
 530 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 531 {
 532         struct debug_bucket *db;
 533         struct debug_obj *obj;
 534         unsigned long flags;
 535
 536         if (!debug_objects_enabled)
 537                 return;
 538
 539         db = get_bucket((unsigned long) addr);
 540
 541         raw_spin_lock_irqsave(&db->lock, flags);
 542
 543         obj = lookup_object(addr, db);
 544         if (obj) {
 545                 switch (obj->state) {
 546                 case ODEBUG_STATE_INIT:
 547                 case ODEBUG_STATE_INACTIVE:
 548                 case ODEBUG_STATE_ACTIVE:
 549                         if (!obj->astate)
 550                                 obj->state = ODEBUG_STATE_INACTIVE;
 551                         else
 552                                 debug_print_object(obj, "deactivate");
 553                         break;
 554
 555                 case ODEBUG_STATE_DESTROYED:
 556                         debug_print_object(obj, "deactivate");
 557                         break;
 558                 default:
 559                         break;
 560                 }
 561         } else {
 562                 struct debug_obj o = { .object = addr,
 563                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 564                                        .descr = descr };
 565
 566                 debug_print_object(&o, "deactivate");
 567         }
 568
 569         raw_spin_unlock_irqrestore(&db->lock, flags);
 570 }
 571 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 572
 573 /**
 574  * debug_object_destroy - debug checks when an object is destroyed
 575  * @addr:       address of the object
 576  * @descr:      pointer to an object specific debug description structure
 577  */
 578 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 579 {
 580         enum debug_obj_state state;
 581         struct debug_bucket *db;
 582         struct debug_obj *obj;
 583         unsigned long flags;
 584
 585         if (!debug_objects_enabled)
 586                 return;
 587
 588         db = get_bucket((unsigned long) addr);
 589
 590         raw_spin_lock_irqsave(&db->lock, flags);
 591
 592         obj = lookup_object(addr, db);
 593         if (!obj)
 594                 goto out_unlock;
 595
 596         switch (obj->state) {
 597         case ODEBUG_STATE_NONE:
 598         case ODEBUG_STATE_INIT:
 599         case ODEBUG_STATE_INACTIVE:
 600                 obj->state = ODEBUG_STATE_DESTROYED;
 601                 break;
 602         case ODEBUG_STATE_ACTIVE:
 603                 debug_print_object(obj, "destroy");
 604                 state = obj->state;
 605                 raw_spin_unlock_irqrestore(&db->lock, flags);
 606                 debug_object_fixup(descr->fixup_destroy, addr, state);
 607                 return;
 608
 609         case ODEBUG_STATE_DESTROYED:
 610                 debug_print_object(obj, "destroy");
 611                 break;
 612         default:
 613                 break;
 614         }
 615 out_unlock:
 616         raw_spin_unlock_irqrestore(&db->lock, flags);
 617 }
 618 EXPORT_SYMBOL_GPL(debug_object_destroy);
 619
 620 /**
 621  * debug_object_free - debug checks when an object is freed
 622  * @addr:       address of the object
 623  * @descr:      pointer to an object specific debug description structure
 624  */
 625 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 626 {
 627         enum debug_obj_state state;
 628         struct debug_bucket *db;
 629         struct debug_obj *obj;
 630         unsigned long flags;
 631
 632         if (!debug_objects_enabled)
 633                 return;
 634
 635         db = get_bucket((unsigned long) addr);
 636
 637         raw_spin_lock_irqsave(&db->lock, flags);
 638
 639         obj = lookup_object(addr, db);
 640         if (!obj)
 641                 goto out_unlock;
 642
 643         switch (obj->state) {
 644         case ODEBUG_STATE_ACTIVE:
 645                 debug_print_object(obj, "free");
 646                 state = obj->state;
 647                 raw_spin_unlock_irqrestore(&db->lock, flags);
 648                 debug_object_fixup(descr->fixup_free, addr, state);
 649                 return;
 650         default:
 651                 hlist_del(&obj->node);
 652                 raw_spin_unlock_irqrestore(&db->lock, flags);
 653                 free_object(obj);
 654                 return;
 655         }
 656 out_unlock:
 657         raw_spin_unlock_irqrestore(&db->lock, flags);
 658 }
 659 EXPORT_SYMBOL_GPL(debug_object_free);
 660
 661 /**
 662  * debug_object_assert_init - debug checks when object should be init-ed
 663  * @addr:       address of the object
 664  * @descr:      pointer to an object specific debug description structure
 665  */
 666 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 667 {
 668         struct debug_bucket *db;
 669         struct debug_obj *obj;
 670         unsigned long flags;
 671
 672         if (!debug_objects_enabled)
 673                 return;
 674
 675         db = get_bucket((unsigned long) addr);
 676
 677         raw_spin_lock_irqsave(&db->lock, flags);
 678
 679         obj = lookup_object(addr, db);
 680         if (!obj) {
 681                 struct debug_obj o = { .object = addr,
 682                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 683                                        .descr = descr };
 684
 685                 raw_spin_unlock_irqrestore(&db->lock, flags);
 686                 /*
 687                  * Maybe the object is static, and we let the type specific
 688                  * code confirm. Track this static object if true, else invoke
 689                  * fixup.
 690                  */
 691                 if (descr->is_static_object && descr->is_static_object(addr)) {
 692                         /* Track this static object */
 693                         debug_object_init(addr, descr);
 694                 } else {
 695                         debug_print_object(&o, "assert_init");
 696                         debug_object_fixup(descr->fixup_assert_init, addr,
 697                                            ODEBUG_STATE_NOTAVAILABLE);
 698                 }
 699                 return;
 700         }
 701
 702         raw_spin_unlock_irqrestore(&db->lock, flags);
 703 }
 704 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 705
 706 /**
 707  * debug_object_active_state - debug checks object usage state machine
 708  * @addr:       address of the object
 709  * @descr:      pointer to an object specific debug description structure
 710  * @expect:     expected state
 711  * @next:       state to move to if expected state is found
 712  */
 713 void
 714 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 715                           unsigned int expect, unsigned int next)
 716 {
 717         struct debug_bucket *db;
 718         struct debug_obj *obj;
 719         unsigned long flags;
 720
 721         if (!debug_objects_enabled)
 722                 return;
 723
 724         db = get_bucket((unsigned long) addr);
 725
 726         raw_spin_lock_irqsave(&db->lock, flags);
 727
 728         obj = lookup_object(addr, db);
 729         if (obj) {
 730                 switch (obj->state) {
 731                 case ODEBUG_STATE_ACTIVE:
 732                         if (obj->astate == expect)
 733                                 obj->astate = next;
 734                         else
 735                                 debug_print_object(obj, "active_state");
 736                         break;
 737
 738                 default:
 739                         debug_print_object(obj, "active_state");
 740                         break;
 741                 }
 742         } else {
 743                 struct debug_obj o = { .object = addr,
 744                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 745                                        .descr = descr };
 746
 747                 debug_print_object(&o, "active_state");
 748         }
 749
 750         raw_spin_unlock_irqrestore(&db->lock, flags);
 751 }
 752 EXPORT_SYMBOL_GPL(debug_object_active_state);
 753
 754 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 755 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 756 {
 757         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 758         struct debug_obj_descr *descr;
 759         enum debug_obj_state state;
 760         struct debug_bucket *db;
 761         struct hlist_node *tmp;
 762         struct debug_obj *obj;
 763         int cnt, objs_checked = 0;
 764         bool work = false;
 765
 766         saddr = (unsigned long) address;
 767         eaddr = saddr + size;
 768         paddr = saddr & ODEBUG_CHUNK_MASK;
 769         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 770         chunks >>= ODEBUG_CHUNK_SHIFT;
 771
 772         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 773                 db = get_bucket(paddr);
 774
 775 repeat:
 776                 cnt = 0;
 777                 raw_spin_lock_irqsave(&db->lock, flags);
 778                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 779                         cnt++;
 780                         oaddr = (unsigned long) obj->object;
 781                         if (oaddr < saddr || oaddr >= eaddr)
 782                                 continue;
 783
 784                         switch (obj->state) {
 785                         case ODEBUG_STATE_ACTIVE:
 786                                 debug_print_object(obj, "free");
 787                                 descr = obj->descr;
 788                                 state = obj->state;
 789                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 790                                 debug_object_fixup(descr->fixup_free,
 791                                                    (void *) oaddr, state);
 792                                 goto repeat;
 793                         default:
 794                                 hlist_del(&obj->node);
 795                                 work |= __free_object(obj);
 796                                 break;
 797                         }
 798                 }
 799                 raw_spin_unlock_irqrestore(&db->lock, flags);
 800
 801                 if (cnt > debug_objects_maxchain)
 802                         debug_objects_maxchain = cnt;
 803
 804                 objs_checked += cnt;
 805         }
 806
 807         if (objs_checked > debug_objects_maxchecked)
 808                 debug_objects_maxchecked = objs_checked;
 809
 810         /* Schedule work to actually kmem_cache_free() objects */
 811         if (work)
 812                 schedule_work(&debug_obj_work);
 813 }
 814
 815 void debug_check_no_obj_freed(const void *address, unsigned long size)
 816 {
 817         if (debug_objects_enabled)
 818                 __debug_check_no_obj_freed(address, size);
 819 }
 820 #endif
 821
 822 #ifdef CONFIG_DEBUG_FS
 823
 824 static int debug_stats_show(struct seq_file *m, void *v)
 825 {
 826         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 827         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
 828         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 829         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 830         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 831         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 832         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 833         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 834         seq_printf(m, "on_free_list  :%d\n", obj_nr_tofree);
 835         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 836         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 837         return 0;
 838 }
 839
 840 static int debug_stats_open(struct inode *inode, struct file *filp)
 841 {
 842         return single_open(filp, debug_stats_show, NULL);
 843 }
 844
 845 static const struct file_operations debug_stats_fops = {
 846         .open           = debug_stats_open,
 847         .read           = seq_read,
 848         .llseek         = seq_lseek,
 849         .release        = single_release,
 850 };
 851
 852 static int __init debug_objects_init_debugfs(void)
 853 {
 854         struct dentry *dbgdir, *dbgstats;
 855
 856         if (!debug_objects_enabled)
 857                 return 0;
 858
 859         dbgdir = debugfs_create_dir("debug_objects", NULL);
 860         if (!dbgdir)
 861                 return -ENOMEM;
 862
 863         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 864                                        &debug_stats_fops);
 865         if (!dbgstats)
 866                 goto err;
 867
 868         return 0;
 869
 870 err:
 871         debugfs_remove(dbgdir);
 872
 873         return -ENOMEM;
 874 }
 875 __initcall(debug_objects_init_debugfs);
 876
 877 #else
 878 static inline void debug_objects_init_debugfs(void) { }
 879 #endif
 880
 881 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 882
 883 /* Random data structure for the self test */
 884 struct self_test {
 885         unsigned long   dummy1[6];
 886         int             static_init;
 887         unsigned long   dummy2[3];
 888 };
 889
 890 static __initdata struct debug_obj_descr descr_type_test;
 891
 892 static bool __init is_static_object(void *addr)
 893 {
 894         struct self_test *obj = addr;
 895
 896         return obj->static_init;
 897 }
 898
 899 /*
 900  * fixup_init is called when:
 901  * - an active object is initialized
 902  */
 903 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 904 {
 905         struct self_test *obj = addr;
 906
 907         switch (state) {
 908         case ODEBUG_STATE_ACTIVE:
 909                 debug_object_deactivate(obj, &descr_type_test);
 910                 debug_object_init(obj, &descr_type_test);
 911                 return true;
 912         default:
 913                 return false;
 914         }
 915 }
 916
 917 /*
 918  * fixup_activate is called when:
 919  * - an active object is activated
 920  * - an unknown non-static object is activated
 921  */
 922 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 923 {
 924         struct self_test *obj = addr;
 925
 926         switch (state) {
 927         case ODEBUG_STATE_NOTAVAILABLE:
 928                 return true;
 929         case ODEBUG_STATE_ACTIVE:
 930                 debug_object_deactivate(obj, &descr_type_test);
 931                 debug_object_activate(obj, &descr_type_test);
 932                 return true;
 933
 934         default:
 935                 return false;
 936         }
 937 }
 938
 939 /*
 940  * fixup_destroy is called when:
 941  * - an active object is destroyed
 942  */
 943 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 944 {
 945         struct self_test *obj = addr;
 946
 947         switch (state) {
 948         case ODEBUG_STATE_ACTIVE:
 949                 debug_object_deactivate(obj, &descr_type_test);
 950                 debug_object_destroy(obj, &descr_type_test);
 951                 return true;
 952         default:
 953                 return false;
 954         }
 955 }
 956
 957 /*
 958  * fixup_free is called when:
 959  * - an active object is freed
 960  */
 961 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 962 {
 963         struct self_test *obj = addr;
 964
 965         switch (state) {
 966         case ODEBUG_STATE_ACTIVE:
 967                 debug_object_deactivate(obj, &descr_type_test);
 968                 debug_object_free(obj, &descr_type_test);
 969                 return true;
 970         default:
 971                 return false;
 972         }
 973 }
 974
 975 static int __init
 976 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 977 {
 978         struct debug_bucket *db;
 979         struct debug_obj *obj;
 980         unsigned long flags;
 981         int res = -EINVAL;
 982
 983         db = get_bucket((unsigned long) addr);
 984
 985         raw_spin_lock_irqsave(&db->lock, flags);
 986
 987         obj = lookup_object(addr, db);
 988         if (!obj && state != ODEBUG_STATE_NONE) {
 989                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 990                 goto out;
 991         }
 992         if (obj && obj->state != state) {
 993                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 994                        obj->state, state);
 995                 goto out;
 996         }
 997         if (fixups != debug_objects_fixups) {
 998                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 999                        fixups, debug_objects_fixups);
1000                 goto out;
1001         }
1002         if (warnings != debug_objects_warnings) {
1003                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1004                        warnings, debug_objects_warnings);
1005                 goto out;
1006         }
1007         res = 0;
1008 out:
1009         raw_spin_unlock_irqrestore(&db->lock, flags);
1010         if (res)
1011                 debug_objects_enabled = 0;
1012         return res;
1013 }
1014
1015 static __initdata struct debug_obj_descr descr_type_test = {
1016         .name                   = "selftest",
1017         .is_static_object       = is_static_object,
1018         .fixup_init             = fixup_init,
1019         .fixup_activate         = fixup_activate,
1020         .fixup_destroy          = fixup_destroy,
1021         .fixup_free             = fixup_free,
1022 };
1023
1024 static __initdata struct self_test obj = { .static_init = 0 };
1025
1026 static void __init debug_objects_selftest(void)
1027 {
1028         int fixups, oldfixups, warnings, oldwarnings;
1029         unsigned long flags;
1030
1031         local_irq_save(flags);
1032
1033         fixups = oldfixups = debug_objects_fixups;
1034         warnings = oldwarnings = debug_objects_warnings;
1035         descr_test = &descr_type_test;
1036
1037         debug_object_init(&obj, &descr_type_test);
1038         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1039                 goto out;
1040         debug_object_activate(&obj, &descr_type_test);
1041         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1042                 goto out;
1043         debug_object_activate(&obj, &descr_type_test);
1044         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1045                 goto out;
1046         debug_object_deactivate(&obj, &descr_type_test);
1047         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1048                 goto out;
1049         debug_object_destroy(&obj, &descr_type_test);
1050         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1051                 goto out;
1052         debug_object_init(&obj, &descr_type_test);
1053         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1054                 goto out;
1055         debug_object_activate(&obj, &descr_type_test);
1056         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1057                 goto out;
1058         debug_object_deactivate(&obj, &descr_type_test);
1059         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1060                 goto out;
1061         debug_object_free(&obj, &descr_type_test);
1062         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1063                 goto out;
1064
1065         obj.static_init = 1;
1066         debug_object_activate(&obj, &descr_type_test);
1067         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1068                 goto out;
1069         debug_object_init(&obj, &descr_type_test);
1070         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1071                 goto out;
1072         debug_object_free(&obj, &descr_type_test);
1073         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1074                 goto out;
1075
1076 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1077         debug_object_init(&obj, &descr_type_test);
1078         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1079                 goto out;
1080         debug_object_activate(&obj, &descr_type_test);
1081         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1082                 goto out;
1083         __debug_check_no_obj_freed(&obj, sizeof(obj));
1084         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1085                 goto out;
1086 #endif
1087         pr_info("selftest passed\n");
1088
1089 out:
1090         debug_objects_fixups = oldfixups;
1091         debug_objects_warnings = oldwarnings;
1092         descr_test = NULL;
1093
1094         local_irq_restore(flags);
1095 }
1096 #else
1097 static inline void debug_objects_selftest(void) { }
1098 #endif
1099
1100 /*
1101  * Called during early boot to initialize the hash buckets and link
1102  * the static object pool objects into the poll list. After this call
1103  * the object tracker is fully operational.
1104  */
1105 void __init debug_objects_early_init(void)
1106 {
1107         int i;
1108
1109         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1110                 raw_spin_lock_init(&obj_hash[i].lock);
1111
1112         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1113                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1114 }
1115
1116 /*
1117  * Convert the statically allocated objects to dynamic ones:
1118  */
1119 static int __init debug_objects_replace_static_objects(void)
1120 {
1121         struct debug_bucket *db = obj_hash;
1122         struct hlist_node *tmp;
1123         struct debug_obj *obj, *new;
1124         HLIST_HEAD(objects);
1125         int i, cnt = 0;
1126
1127         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1128                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1129                 if (!obj)
1130                         goto free;
1131                 kmemleak_ignore(obj);
1132                 hlist_add_head(&obj->node, &objects);
1133         }
1134
1135         /*
1136          * When debug_objects_mem_init() is called we know that only
1137          * one CPU is up, so disabling interrupts is enough
1138          * protection. This avoids the lockdep hell of lock ordering.
1139          */
1140         local_irq_disable();
1141
1142         /* Remove the statically allocated objects from the pool */
1143         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1144                 hlist_del(&obj->node);
1145         /* Move the allocated objects to the pool */
1146         hlist_move_list(&objects, &obj_pool);
1147
1148         /* Replace the active object references */
1149         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1150                 hlist_move_list(&db->list, &objects);
1151
1152                 hlist_for_each_entry(obj, &objects, node) {
1153                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1154                         hlist_del(&new->node);
1155                         /* copy object data */
1156                         *new = *obj;
1157                         hlist_add_head(&new->node, &db->list);
1158                         cnt++;
1159                 }
1160         }
1161         local_irq_enable();
1162
1163         pr_debug("%d of %d active objects replaced\n",
1164                  cnt, obj_pool_used);
1165         return 0;
1166 free:
1167         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1168                 hlist_del(&obj->node);
1169                 kmem_cache_free(obj_cache, obj);
1170         }
1171         return -ENOMEM;
1172 }
1173
1174 /*
1175  * Called after the kmem_caches are functional to setup a dedicated
1176  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1177  * prevents that the debug code is called on kmem_cache_free() for the
1178  * debug tracker objects to avoid recursive calls.
1179  */
1180 void __init debug_objects_mem_init(void)
1181 {
1182         if (!debug_objects_enabled)
1183                 return;
1184
1185         obj_cache = kmem_cache_create("debug_objects_cache",
1186                                       sizeof (struct debug_obj), 0,
1187                                       SLAB_DEBUG_OBJECTS, NULL);
1188
1189         if (!obj_cache || debug_objects_replace_static_objects()) {
1190                 debug_objects_enabled = 0;
1191                 kmem_cache_destroy(obj_cache);
1192                 pr_warn("out of memory.\n");
1193         } else
1194                 debug_objects_selftest();
1195
1196         /*
1197          * Increase the thresholds for allocating and freeing objects
1198          * according to the number of possible CPUs available in the system.
1199          */
1200         debug_objects_pool_size += num_possible_cpus() * 32;
1201         debug_objects_pool_min_level += num_possible_cpus() * 4;
1202 }