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 #define ODEBUG_POOL_PERCPU_SIZE 64
  29 #define ODEBUG_BATCH_SIZE       16
  30
  31 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  32 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  33 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  34
  35 /*
  36  * We limit the freeing of debug objects via workqueue at a maximum
  37  * frequency of 10Hz and about 1024 objects for each freeing operation.
  38  * So it is freeing at most 10k debug objects per second.
  39  */
  40 #define ODEBUG_FREE_WORK_MAX    1024
  41 #define ODEBUG_FREE_WORK_DELAY  DIV_ROUND_UP(HZ, 10)
  42
  43 struct debug_bucket {
  44         struct hlist_head       list;
  45         raw_spinlock_t          lock;
  46 };
  47
  48 /*
  49  * Debug object percpu free list
  50  * Access is protected by disabling irq
  51  */
  52 struct debug_percpu_free {
  53         struct hlist_head       free_objs;
  54         int                     obj_free;
  55 };
  56
  57 static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
  58
  59 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  60
  61 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  62
  63 static DEFINE_RAW_SPINLOCK(pool_lock);
  64
  65 static HLIST_HEAD(obj_pool);
  66 static HLIST_HEAD(obj_to_free);
  67
  68 /*
  69  * Because of the presence of percpu free pools, obj_pool_free will
  70  * under-count those in the percpu free pools. Similarly, obj_pool_used
  71  * will over-count those in the percpu free pools. Adjustments will be
  72  * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
  73  * can be off.
  74  */
  75 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  76 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  77 static int                      obj_pool_used;
  78 static int                      obj_pool_max_used;
  79 static bool                     obj_freeing;
  80 /* The number of objs on the global free list */
  81 static int                      obj_nr_tofree;
  82
  83 static int                      debug_objects_maxchain __read_mostly;
  84 static int __maybe_unused       debug_objects_maxchecked __read_mostly;
  85 static int                      debug_objects_fixups __read_mostly;
  86 static int                      debug_objects_warnings __read_mostly;
  87 static int                      debug_objects_enabled __read_mostly
  88                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  89 static int                      debug_objects_pool_size __read_mostly
  90                                 = ODEBUG_POOL_SIZE;
  91 static int                      debug_objects_pool_min_level __read_mostly
  92                                 = ODEBUG_POOL_MIN_LEVEL;
  93 static struct debug_obj_descr   *descr_test  __read_mostly;
  94 static struct kmem_cache        *obj_cache __read_mostly;
  95
  96 /*
  97  * Track numbers of kmem_cache_alloc()/free() calls done.
  98  */
  99 static int                      debug_objects_allocated;
 100 static int                      debug_objects_freed;
 101
 102 static void free_obj_work(struct work_struct *work);
 103 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
 104
 105 static int __init enable_object_debug(char *str)
 106 {
 107         debug_objects_enabled = 1;
 108         return 0;
 109 }
 110
 111 static int __init disable_object_debug(char *str)
 112 {
 113         debug_objects_enabled = 0;
 114         return 0;
 115 }
 116
 117 early_param("debug_objects", enable_object_debug);
 118 early_param("no_debug_objects", disable_object_debug);
 119
 120 static const char *obj_states[ODEBUG_STATE_MAX] = {
 121         [ODEBUG_STATE_NONE]             = "none",
 122         [ODEBUG_STATE_INIT]             = "initialized",
 123         [ODEBUG_STATE_INACTIVE]         = "inactive",
 124         [ODEBUG_STATE_ACTIVE]           = "active",
 125         [ODEBUG_STATE_DESTROYED]        = "destroyed",
 126         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
 127 };
 128
 129 static void fill_pool(void)
 130 {
 131         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
 132         struct debug_obj *obj;
 133         unsigned long flags;
 134
 135         if (likely(obj_pool_free >= debug_objects_pool_min_level))
 136                 return;
 137
 138         /*
 139          * Reuse objs from the global free list; they will be reinitialized
 140          * when allocating.
 141          */
 142         while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 143                 raw_spin_lock_irqsave(&pool_lock, flags);
 144                 /*
 145                  * Recheck with the lock held as the worker thread might have
 146                  * won the race and freed the global free list already.
 147                  */
 148                 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 149                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 150                         hlist_del(&obj->node);
 151                         obj_nr_tofree--;
 152                         hlist_add_head(&obj->node, &obj_pool);
 153                         obj_pool_free++;
 154                 }
 155                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 156         }
 157
 158         if (unlikely(!obj_cache))
 159                 return;
 160
 161         while (obj_pool_free < debug_objects_pool_min_level) {
 162                 struct debug_obj *new[ODEBUG_BATCH_SIZE];
 163                 int cnt;
 164
 165                 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
 166                         new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
 167                         if (!new[cnt])
 168                                 break;
 169                 }
 170                 if (!cnt)
 171                         return;
 172
 173                 raw_spin_lock_irqsave(&pool_lock, flags);
 174                 while (cnt) {
 175                         hlist_add_head(&new[--cnt]->node, &obj_pool);
 176                         debug_objects_allocated++;
 177                         obj_pool_free++;
 178                 }
 179                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 180         }
 181 }
 182
 183 /*
 184  * Lookup an object in the hash bucket.
 185  */
 186 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 187 {
 188         struct debug_obj *obj;
 189         int cnt = 0;
 190
 191         hlist_for_each_entry(obj, &b->list, node) {
 192                 cnt++;
 193                 if (obj->object == addr)
 194                         return obj;
 195         }
 196         if (cnt > debug_objects_maxchain)
 197                 debug_objects_maxchain = cnt;
 198
 199         return NULL;
 200 }
 201
 202 /*
 203  * Allocate a new object from the hlist
 204  */
 205 static struct debug_obj *__alloc_object(struct hlist_head *list)
 206 {
 207         struct debug_obj *obj = NULL;
 208
 209         if (list->first) {
 210                 obj = hlist_entry(list->first, typeof(*obj), node);
 211                 hlist_del(&obj->node);
 212         }
 213
 214         return obj;
 215 }
 216
 217 /*
 218  * Allocate a new object. If the pool is empty, switch off the debugger.
 219  * Must be called with interrupts disabled.
 220  */
 221 static struct debug_obj *
 222 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 223 {
 224         struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 225         struct debug_obj *obj;
 226
 227         if (likely(obj_cache)) {
 228                 obj = __alloc_object(&percpu_pool->free_objs);
 229                 if (obj) {
 230                         percpu_pool->obj_free--;
 231                         goto init_obj;
 232                 }
 233         }
 234
 235         raw_spin_lock(&pool_lock);
 236         obj = __alloc_object(&obj_pool);
 237         if (obj) {
 238                 obj_pool_used++;
 239                 obj_pool_free--;
 240
 241                 /*
 242                  * Looking ahead, allocate one batch of debug objects and
 243                  * put them into the percpu free pool.
 244                  */
 245                 if (likely(obj_cache)) {
 246                         int i;
 247
 248                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 249                                 struct debug_obj *obj2;
 250
 251                                 obj2 = __alloc_object(&obj_pool);
 252                                 if (!obj2)
 253                                         break;
 254                                 hlist_add_head(&obj2->node,
 255                                                &percpu_pool->free_objs);
 256                                 percpu_pool->obj_free++;
 257                                 obj_pool_used++;
 258                                 obj_pool_free--;
 259                         }
 260                 }
 261
 262                 if (obj_pool_used > obj_pool_max_used)
 263                         obj_pool_max_used = obj_pool_used;
 264
 265                 if (obj_pool_free < obj_pool_min_free)
 266                         obj_pool_min_free = obj_pool_free;
 267         }
 268         raw_spin_unlock(&pool_lock);
 269
 270 init_obj:
 271         if (obj) {
 272                 obj->object = addr;
 273                 obj->descr  = descr;
 274                 obj->state  = ODEBUG_STATE_NONE;
 275                 obj->astate = 0;
 276                 hlist_add_head(&obj->node, &b->list);
 277         }
 278         return obj;
 279 }
 280
 281 /*
 282  * workqueue function to free objects.
 283  *
 284  * To reduce contention on the global pool_lock, the actual freeing of
 285  * debug objects will be delayed if the pool_lock is busy.
 286  */
 287 static void free_obj_work(struct work_struct *work)
 288 {
 289         struct hlist_node *tmp;
 290         struct debug_obj *obj;
 291         unsigned long flags;
 292         HLIST_HEAD(tofree);
 293
 294         WRITE_ONCE(obj_freeing, false);
 295         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 296                 return;
 297
 298         if (obj_pool_free >= debug_objects_pool_size)
 299                 goto free_objs;
 300
 301         /*
 302          * The objs on the pool list might be allocated before the work is
 303          * run, so recheck if pool list it full or not, if not fill pool
 304          * list from the global free list. As it is likely that a workload
 305          * may be gearing up to use more and more objects, don't free any
 306          * of them until the next round.
 307          */
 308         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 309                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 310                 hlist_del(&obj->node);
 311                 hlist_add_head(&obj->node, &obj_pool);
 312                 obj_pool_free++;
 313                 obj_nr_tofree--;
 314         }
 315         raw_spin_unlock_irqrestore(&pool_lock, flags);
 316         return;
 317
 318 free_objs:
 319         /*
 320          * Pool list is already full and there are still objs on the free
 321          * list. Move remaining free objs to a temporary list to free the
 322          * memory outside the pool_lock held region.
 323          */
 324         if (obj_nr_tofree) {
 325                 hlist_move_list(&obj_to_free, &tofree);
 326                 debug_objects_freed += obj_nr_tofree;
 327                 obj_nr_tofree = 0;
 328         }
 329         raw_spin_unlock_irqrestore(&pool_lock, flags);
 330
 331         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 332                 hlist_del(&obj->node);
 333                 kmem_cache_free(obj_cache, obj);
 334         }
 335 }
 336
 337 static void __free_object(struct debug_obj *obj)
 338 {
 339         struct debug_obj *objs[ODEBUG_BATCH_SIZE];
 340         struct debug_percpu_free *percpu_pool;
 341         int lookahead_count = 0;
 342         unsigned long flags;
 343         bool work;
 344
 345         local_irq_save(flags);
 346         if (!obj_cache)
 347                 goto free_to_obj_pool;
 348
 349         /*
 350          * Try to free it into the percpu pool first.
 351          */
 352         percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 353         if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
 354                 hlist_add_head(&obj->node, &percpu_pool->free_objs);
 355                 percpu_pool->obj_free++;
 356                 local_irq_restore(flags);
 357                 return;
 358         }
 359
 360         /*
 361          * As the percpu pool is full, look ahead and pull out a batch
 362          * of objects from the percpu pool and free them as well.
 363          */
 364         for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
 365                 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
 366                 if (!objs[lookahead_count])
 367                         break;
 368                 percpu_pool->obj_free--;
 369         }
 370
 371 free_to_obj_pool:
 372         raw_spin_lock(&pool_lock);
 373         work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
 374                (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
 375         obj_pool_used--;
 376
 377         if (work) {
 378                 obj_nr_tofree++;
 379                 hlist_add_head(&obj->node, &obj_to_free);
 380                 if (lookahead_count) {
 381                         obj_nr_tofree += lookahead_count;
 382                         obj_pool_used -= lookahead_count;
 383                         while (lookahead_count) {
 384                                 hlist_add_head(&objs[--lookahead_count]->node,
 385                                                &obj_to_free);
 386                         }
 387                 }
 388
 389                 if ((obj_pool_free > debug_objects_pool_size) &&
 390                     (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
 391                         int i;
 392
 393                         /*
 394                          * Free one more batch of objects from obj_pool.
 395                          */
 396                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 397                                 obj = __alloc_object(&obj_pool);
 398                                 hlist_add_head(&obj->node, &obj_to_free);
 399                                 obj_pool_free--;
 400                                 obj_nr_tofree++;
 401                         }
 402                 }
 403         } else {
 404                 obj_pool_free++;
 405                 hlist_add_head(&obj->node, &obj_pool);
 406                 if (lookahead_count) {
 407                         obj_pool_free += lookahead_count;
 408                         obj_pool_used -= lookahead_count;
 409                         while (lookahead_count) {
 410                                 hlist_add_head(&objs[--lookahead_count]->node,
 411                                                &obj_pool);
 412                         }
 413                 }
 414         }
 415         raw_spin_unlock(&pool_lock);
 416         local_irq_restore(flags);
 417 }
 418
 419 /*
 420  * Put the object back into the pool and schedule work to free objects
 421  * if necessary.
 422  */
 423 static void free_object(struct debug_obj *obj)
 424 {
 425         __free_object(obj);
 426         if (!obj_freeing && obj_nr_tofree) {
 427                 WRITE_ONCE(obj_freeing, true);
 428                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
 429         }
 430 }
 431
 432 /*
 433  * We run out of memory. That means we probably have tons of objects
 434  * allocated.
 435  */
 436 static void debug_objects_oom(void)
 437 {
 438         struct debug_bucket *db = obj_hash;
 439         struct hlist_node *tmp;
 440         HLIST_HEAD(freelist);
 441         struct debug_obj *obj;
 442         unsigned long flags;
 443         int i;
 444
 445         pr_warn("Out of memory. ODEBUG disabled\n");
 446
 447         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 448                 raw_spin_lock_irqsave(&db->lock, flags);
 449                 hlist_move_list(&db->list, &freelist);
 450                 raw_spin_unlock_irqrestore(&db->lock, flags);
 451
 452                 /* Now free them */
 453                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 454                         hlist_del(&obj->node);
 455                         free_object(obj);
 456                 }
 457         }
 458 }
 459
 460 /*
 461  * We use the pfn of the address for the hash. That way we can check
 462  * for freed objects simply by checking the affected bucket.
 463  */
 464 static struct debug_bucket *get_bucket(unsigned long addr)
 465 {
 466         unsigned long hash;
 467
 468         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 469         return &obj_hash[hash];
 470 }
 471
 472 static void debug_print_object(struct debug_obj *obj, char *msg)
 473 {
 474         struct debug_obj_descr *descr = obj->descr;
 475         static int limit;
 476
 477         if (limit < 5 && descr != descr_test) {
 478                 void *hint = descr->debug_hint ?
 479                         descr->debug_hint(obj->object) : NULL;
 480                 limit++;
 481                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 482                                  "object type: %s hint: %pS\n",
 483                         msg, obj_states[obj->state], obj->astate,
 484                         descr->name, hint);
 485         }
 486         debug_objects_warnings++;
 487 }
 488
 489 /*
 490  * Try to repair the damage, so we have a better chance to get useful
 491  * debug output.
 492  */
 493 static bool
 494 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 495                    void * addr, enum debug_obj_state state)
 496 {
 497         if (fixup && fixup(addr, state)) {
 498                 debug_objects_fixups++;
 499                 return true;
 500         }
 501         return false;
 502 }
 503
 504 static void debug_object_is_on_stack(void *addr, int onstack)
 505 {
 506         int is_on_stack;
 507         static int limit;
 508
 509         if (limit > 4)
 510                 return;
 511
 512         is_on_stack = object_is_on_stack(addr);
 513         if (is_on_stack == onstack)
 514                 return;
 515
 516         limit++;
 517         if (is_on_stack)
 518                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 519                          task_stack_page(current));
 520         else
 521                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 522                          task_stack_page(current));
 523
 524         WARN_ON(1);
 525 }
 526
 527 static void
 528 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 529 {
 530         enum debug_obj_state state;
 531         struct debug_bucket *db;
 532         struct debug_obj *obj;
 533         unsigned long flags;
 534
 535         fill_pool();
 536
 537         db = get_bucket((unsigned long) addr);
 538
 539         raw_spin_lock_irqsave(&db->lock, flags);
 540
 541         obj = lookup_object(addr, db);
 542         if (!obj) {
 543                 obj = alloc_object(addr, db, descr);
 544                 if (!obj) {
 545                         debug_objects_enabled = 0;
 546                         raw_spin_unlock_irqrestore(&db->lock, flags);
 547                         debug_objects_oom();
 548                         return;
 549                 }
 550                 debug_object_is_on_stack(addr, onstack);
 551         }
 552
 553         switch (obj->state) {
 554         case ODEBUG_STATE_NONE:
 555         case ODEBUG_STATE_INIT:
 556         case ODEBUG_STATE_INACTIVE:
 557                 obj->state = ODEBUG_STATE_INIT;
 558                 break;
 559
 560         case ODEBUG_STATE_ACTIVE:
 561                 debug_print_object(obj, "init");
 562                 state = obj->state;
 563                 raw_spin_unlock_irqrestore(&db->lock, flags);
 564                 debug_object_fixup(descr->fixup_init, addr, state);
 565                 return;
 566
 567         case ODEBUG_STATE_DESTROYED:
 568                 debug_print_object(obj, "init");
 569                 break;
 570         default:
 571                 break;
 572         }
 573
 574         raw_spin_unlock_irqrestore(&db->lock, flags);
 575 }
 576
 577 /**
 578  * debug_object_init - debug checks when an object is initialized
 579  * @addr:       address of the object
 580  * @descr:      pointer to an object specific debug description structure
 581  */
 582 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 583 {
 584         if (!debug_objects_enabled)
 585                 return;
 586
 587         __debug_object_init(addr, descr, 0);
 588 }
 589 EXPORT_SYMBOL_GPL(debug_object_init);
 590
 591 /**
 592  * debug_object_init_on_stack - debug checks when an object on stack is
 593  *                              initialized
 594  * @addr:       address of the object
 595  * @descr:      pointer to an object specific debug description structure
 596  */
 597 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 598 {
 599         if (!debug_objects_enabled)
 600                 return;
 601
 602         __debug_object_init(addr, descr, 1);
 603 }
 604 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 605
 606 /**
 607  * debug_object_activate - debug checks when an object is activated
 608  * @addr:       address of the object
 609  * @descr:      pointer to an object specific debug description structure
 610  * Returns 0 for success, -EINVAL for check failed.
 611  */
 612 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 613 {
 614         enum debug_obj_state state;
 615         struct debug_bucket *db;
 616         struct debug_obj *obj;
 617         unsigned long flags;
 618         int ret;
 619         struct debug_obj o = { .object = addr,
 620                                .state = ODEBUG_STATE_NOTAVAILABLE,
 621                                .descr = descr };
 622
 623         if (!debug_objects_enabled)
 624                 return 0;
 625
 626         db = get_bucket((unsigned long) addr);
 627
 628         raw_spin_lock_irqsave(&db->lock, flags);
 629
 630         obj = lookup_object(addr, db);
 631         if (obj) {
 632                 switch (obj->state) {
 633                 case ODEBUG_STATE_INIT:
 634                 case ODEBUG_STATE_INACTIVE:
 635                         obj->state = ODEBUG_STATE_ACTIVE;
 636                         ret = 0;
 637                         break;
 638
 639                 case ODEBUG_STATE_ACTIVE:
 640                         debug_print_object(obj, "activate");
 641                         state = obj->state;
 642                         raw_spin_unlock_irqrestore(&db->lock, flags);
 643                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 644                         return ret ? 0 : -EINVAL;
 645
 646                 case ODEBUG_STATE_DESTROYED:
 647                         debug_print_object(obj, "activate");
 648                         ret = -EINVAL;
 649                         break;
 650                 default:
 651                         ret = 0;
 652                         break;
 653                 }
 654                 raw_spin_unlock_irqrestore(&db->lock, flags);
 655                 return ret;
 656         }
 657
 658         raw_spin_unlock_irqrestore(&db->lock, flags);
 659         /*
 660          * We are here when a static object is activated. We
 661          * let the type specific code confirm whether this is
 662          * true or not. if true, we just make sure that the
 663          * static object is tracked in the object tracker. If
 664          * not, this must be a bug, so we try to fix it up.
 665          */
 666         if (descr->is_static_object && descr->is_static_object(addr)) {
 667                 /* track this static object */
 668                 debug_object_init(addr, descr);
 669                 debug_object_activate(addr, descr);
 670         } else {
 671                 debug_print_object(&o, "activate");
 672                 ret = debug_object_fixup(descr->fixup_activate, addr,
 673                                         ODEBUG_STATE_NOTAVAILABLE);
 674                 return ret ? 0 : -EINVAL;
 675         }
 676         return 0;
 677 }
 678 EXPORT_SYMBOL_GPL(debug_object_activate);
 679
 680 /**
 681  * debug_object_deactivate - debug checks when an object is deactivated
 682  * @addr:       address of the object
 683  * @descr:      pointer to an object specific debug description structure
 684  */
 685 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 686 {
 687         struct debug_bucket *db;
 688         struct debug_obj *obj;
 689         unsigned long flags;
 690
 691         if (!debug_objects_enabled)
 692                 return;
 693
 694         db = get_bucket((unsigned long) addr);
 695
 696         raw_spin_lock_irqsave(&db->lock, flags);
 697
 698         obj = lookup_object(addr, db);
 699         if (obj) {
 700                 switch (obj->state) {
 701                 case ODEBUG_STATE_INIT:
 702                 case ODEBUG_STATE_INACTIVE:
 703                 case ODEBUG_STATE_ACTIVE:
 704                         if (!obj->astate)
 705                                 obj->state = ODEBUG_STATE_INACTIVE;
 706                         else
 707                                 debug_print_object(obj, "deactivate");
 708                         break;
 709
 710                 case ODEBUG_STATE_DESTROYED:
 711                         debug_print_object(obj, "deactivate");
 712                         break;
 713                 default:
 714                         break;
 715                 }
 716         } else {
 717                 struct debug_obj o = { .object = addr,
 718                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 719                                        .descr = descr };
 720
 721                 debug_print_object(&o, "deactivate");
 722         }
 723
 724         raw_spin_unlock_irqrestore(&db->lock, flags);
 725 }
 726 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 727
 728 /**
 729  * debug_object_destroy - debug checks when an object is destroyed
 730  * @addr:       address of the object
 731  * @descr:      pointer to an object specific debug description structure
 732  */
 733 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 734 {
 735         enum debug_obj_state state;
 736         struct debug_bucket *db;
 737         struct debug_obj *obj;
 738         unsigned long flags;
 739
 740         if (!debug_objects_enabled)
 741                 return;
 742
 743         db = get_bucket((unsigned long) addr);
 744
 745         raw_spin_lock_irqsave(&db->lock, flags);
 746
 747         obj = lookup_object(addr, db);
 748         if (!obj)
 749                 goto out_unlock;
 750
 751         switch (obj->state) {
 752         case ODEBUG_STATE_NONE:
 753         case ODEBUG_STATE_INIT:
 754         case ODEBUG_STATE_INACTIVE:
 755                 obj->state = ODEBUG_STATE_DESTROYED;
 756                 break;
 757         case ODEBUG_STATE_ACTIVE:
 758                 debug_print_object(obj, "destroy");
 759                 state = obj->state;
 760                 raw_spin_unlock_irqrestore(&db->lock, flags);
 761                 debug_object_fixup(descr->fixup_destroy, addr, state);
 762                 return;
 763
 764         case ODEBUG_STATE_DESTROYED:
 765                 debug_print_object(obj, "destroy");
 766                 break;
 767         default:
 768                 break;
 769         }
 770 out_unlock:
 771         raw_spin_unlock_irqrestore(&db->lock, flags);
 772 }
 773 EXPORT_SYMBOL_GPL(debug_object_destroy);
 774
 775 /**
 776  * debug_object_free - debug checks when an object is freed
 777  * @addr:       address of the object
 778  * @descr:      pointer to an object specific debug description structure
 779  */
 780 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 781 {
 782         enum debug_obj_state state;
 783         struct debug_bucket *db;
 784         struct debug_obj *obj;
 785         unsigned long flags;
 786
 787         if (!debug_objects_enabled)
 788                 return;
 789
 790         db = get_bucket((unsigned long) addr);
 791
 792         raw_spin_lock_irqsave(&db->lock, flags);
 793
 794         obj = lookup_object(addr, db);
 795         if (!obj)
 796                 goto out_unlock;
 797
 798         switch (obj->state) {
 799         case ODEBUG_STATE_ACTIVE:
 800                 debug_print_object(obj, "free");
 801                 state = obj->state;
 802                 raw_spin_unlock_irqrestore(&db->lock, flags);
 803                 debug_object_fixup(descr->fixup_free, addr, state);
 804                 return;
 805         default:
 806                 hlist_del(&obj->node);
 807                 raw_spin_unlock_irqrestore(&db->lock, flags);
 808                 free_object(obj);
 809                 return;
 810         }
 811 out_unlock:
 812         raw_spin_unlock_irqrestore(&db->lock, flags);
 813 }
 814 EXPORT_SYMBOL_GPL(debug_object_free);
 815
 816 /**
 817  * debug_object_assert_init - debug checks when object should be init-ed
 818  * @addr:       address of the object
 819  * @descr:      pointer to an object specific debug description structure
 820  */
 821 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 822 {
 823         struct debug_bucket *db;
 824         struct debug_obj *obj;
 825         unsigned long flags;
 826
 827         if (!debug_objects_enabled)
 828                 return;
 829
 830         db = get_bucket((unsigned long) addr);
 831
 832         raw_spin_lock_irqsave(&db->lock, flags);
 833
 834         obj = lookup_object(addr, db);
 835         if (!obj) {
 836                 struct debug_obj o = { .object = addr,
 837                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 838                                        .descr = descr };
 839
 840                 raw_spin_unlock_irqrestore(&db->lock, flags);
 841                 /*
 842                  * Maybe the object is static, and we let the type specific
 843                  * code confirm. Track this static object if true, else invoke
 844                  * fixup.
 845                  */
 846                 if (descr->is_static_object && descr->is_static_object(addr)) {
 847                         /* Track this static object */
 848                         debug_object_init(addr, descr);
 849                 } else {
 850                         debug_print_object(&o, "assert_init");
 851                         debug_object_fixup(descr->fixup_assert_init, addr,
 852                                            ODEBUG_STATE_NOTAVAILABLE);
 853                 }
 854                 return;
 855         }
 856
 857         raw_spin_unlock_irqrestore(&db->lock, flags);
 858 }
 859 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 860
 861 /**
 862  * debug_object_active_state - debug checks object usage state machine
 863  * @addr:       address of the object
 864  * @descr:      pointer to an object specific debug description structure
 865  * @expect:     expected state
 866  * @next:       state to move to if expected state is found
 867  */
 868 void
 869 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 870                           unsigned int expect, unsigned int next)
 871 {
 872         struct debug_bucket *db;
 873         struct debug_obj *obj;
 874         unsigned long flags;
 875
 876         if (!debug_objects_enabled)
 877                 return;
 878
 879         db = get_bucket((unsigned long) addr);
 880
 881         raw_spin_lock_irqsave(&db->lock, flags);
 882
 883         obj = lookup_object(addr, db);
 884         if (obj) {
 885                 switch (obj->state) {
 886                 case ODEBUG_STATE_ACTIVE:
 887                         if (obj->astate == expect)
 888                                 obj->astate = next;
 889                         else
 890                                 debug_print_object(obj, "active_state");
 891                         break;
 892
 893                 default:
 894                         debug_print_object(obj, "active_state");
 895                         break;
 896                 }
 897         } else {
 898                 struct debug_obj o = { .object = addr,
 899                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 900                                        .descr = descr };
 901
 902                 debug_print_object(&o, "active_state");
 903         }
 904
 905         raw_spin_unlock_irqrestore(&db->lock, flags);
 906 }
 907 EXPORT_SYMBOL_GPL(debug_object_active_state);
 908
 909 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 910 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 911 {
 912         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 913         struct debug_obj_descr *descr;
 914         enum debug_obj_state state;
 915         struct debug_bucket *db;
 916         struct hlist_node *tmp;
 917         struct debug_obj *obj;
 918         int cnt, objs_checked = 0;
 919
 920         saddr = (unsigned long) address;
 921         eaddr = saddr + size;
 922         paddr = saddr & ODEBUG_CHUNK_MASK;
 923         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 924         chunks >>= ODEBUG_CHUNK_SHIFT;
 925
 926         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 927                 db = get_bucket(paddr);
 928
 929 repeat:
 930                 cnt = 0;
 931                 raw_spin_lock_irqsave(&db->lock, flags);
 932                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 933                         cnt++;
 934                         oaddr = (unsigned long) obj->object;
 935                         if (oaddr < saddr || oaddr >= eaddr)
 936                                 continue;
 937
 938                         switch (obj->state) {
 939                         case ODEBUG_STATE_ACTIVE:
 940                                 debug_print_object(obj, "free");
 941                                 descr = obj->descr;
 942                                 state = obj->state;
 943                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 944                                 debug_object_fixup(descr->fixup_free,
 945                                                    (void *) oaddr, state);
 946                                 goto repeat;
 947                         default:
 948                                 hlist_del(&obj->node);
 949                                 __free_object(obj);
 950                                 break;
 951                         }
 952                 }
 953                 raw_spin_unlock_irqrestore(&db->lock, flags);
 954
 955                 if (cnt > debug_objects_maxchain)
 956                         debug_objects_maxchain = cnt;
 957
 958                 objs_checked += cnt;
 959         }
 960
 961         if (objs_checked > debug_objects_maxchecked)
 962                 debug_objects_maxchecked = objs_checked;
 963
 964         /* Schedule work to actually kmem_cache_free() objects */
 965         if (!obj_freeing && obj_nr_tofree) {
 966                 WRITE_ONCE(obj_freeing, true);
 967                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
 968         }
 969 }
 970
 971 void debug_check_no_obj_freed(const void *address, unsigned long size)
 972 {
 973         if (debug_objects_enabled)
 974                 __debug_check_no_obj_freed(address, size);
 975 }
 976 #endif
 977
 978 #ifdef CONFIG_DEBUG_FS
 979
 980 static int debug_stats_show(struct seq_file *m, void *v)
 981 {
 982         int cpu, obj_percpu_free = 0;
 983
 984         for_each_possible_cpu(cpu)
 985                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
 986
 987         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 988         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
 989         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 990         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 991         seq_printf(m, "pool_free     :%d\n", obj_pool_free + obj_percpu_free);
 992         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
 993         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 994         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
 995         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 996         seq_printf(m, "on_free_list  :%d\n", obj_nr_tofree);
 997         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 998         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 999         return 0;
1000 }
1001
1002 static int debug_stats_open(struct inode *inode, struct file *filp)
1003 {
1004         return single_open(filp, debug_stats_show, NULL);
1005 }
1006
1007 static const struct file_operations debug_stats_fops = {
1008         .open           = debug_stats_open,
1009         .read           = seq_read,
1010         .llseek         = seq_lseek,
1011         .release        = single_release,
1012 };
1013
1014 static int __init debug_objects_init_debugfs(void)
1015 {
1016         struct dentry *dbgdir;
1017
1018         if (!debug_objects_enabled)
1019                 return 0;
1020
1021         dbgdir = debugfs_create_dir("debug_objects", NULL);
1022
1023         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1024
1025         return 0;
1026 }
1027 __initcall(debug_objects_init_debugfs);
1028
1029 #else
1030 static inline void debug_objects_init_debugfs(void) { }
1031 #endif
1032
1033 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1034
1035 /* Random data structure for the self test */
1036 struct self_test {
1037         unsigned long   dummy1[6];
1038         int             static_init;
1039         unsigned long   dummy2[3];
1040 };
1041
1042 static __initdata struct debug_obj_descr descr_type_test;
1043
1044 static bool __init is_static_object(void *addr)
1045 {
1046         struct self_test *obj = addr;
1047
1048         return obj->static_init;
1049 }
1050
1051 /*
1052  * fixup_init is called when:
1053  * - an active object is initialized
1054  */
1055 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1056 {
1057         struct self_test *obj = addr;
1058
1059         switch (state) {
1060         case ODEBUG_STATE_ACTIVE:
1061                 debug_object_deactivate(obj, &descr_type_test);
1062                 debug_object_init(obj, &descr_type_test);
1063                 return true;
1064         default:
1065                 return false;
1066         }
1067 }
1068
1069 /*
1070  * fixup_activate is called when:
1071  * - an active object is activated
1072  * - an unknown non-static object is activated
1073  */
1074 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1075 {
1076         struct self_test *obj = addr;
1077
1078         switch (state) {
1079         case ODEBUG_STATE_NOTAVAILABLE:
1080                 return true;
1081         case ODEBUG_STATE_ACTIVE:
1082                 debug_object_deactivate(obj, &descr_type_test);
1083                 debug_object_activate(obj, &descr_type_test);
1084                 return true;
1085
1086         default:
1087                 return false;
1088         }
1089 }
1090
1091 /*
1092  * fixup_destroy is called when:
1093  * - an active object is destroyed
1094  */
1095 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1096 {
1097         struct self_test *obj = addr;
1098
1099         switch (state) {
1100         case ODEBUG_STATE_ACTIVE:
1101                 debug_object_deactivate(obj, &descr_type_test);
1102                 debug_object_destroy(obj, &descr_type_test);
1103                 return true;
1104         default:
1105                 return false;
1106         }
1107 }
1108
1109 /*
1110  * fixup_free is called when:
1111  * - an active object is freed
1112  */
1113 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1114 {
1115         struct self_test *obj = addr;
1116
1117         switch (state) {
1118         case ODEBUG_STATE_ACTIVE:
1119                 debug_object_deactivate(obj, &descr_type_test);
1120                 debug_object_free(obj, &descr_type_test);
1121                 return true;
1122         default:
1123                 return false;
1124         }
1125 }
1126
1127 static int __init
1128 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1129 {
1130         struct debug_bucket *db;
1131         struct debug_obj *obj;
1132         unsigned long flags;
1133         int res = -EINVAL;
1134
1135         db = get_bucket((unsigned long) addr);
1136
1137         raw_spin_lock_irqsave(&db->lock, flags);
1138
1139         obj = lookup_object(addr, db);
1140         if (!obj && state != ODEBUG_STATE_NONE) {
1141                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1142                 goto out;
1143         }
1144         if (obj && obj->state != state) {
1145                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1146                        obj->state, state);
1147                 goto out;
1148         }
1149         if (fixups != debug_objects_fixups) {
1150                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1151                        fixups, debug_objects_fixups);
1152                 goto out;
1153         }
1154         if (warnings != debug_objects_warnings) {
1155                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1156                        warnings, debug_objects_warnings);
1157                 goto out;
1158         }
1159         res = 0;
1160 out:
1161         raw_spin_unlock_irqrestore(&db->lock, flags);
1162         if (res)
1163                 debug_objects_enabled = 0;
1164         return res;
1165 }
1166
1167 static __initdata struct debug_obj_descr descr_type_test = {
1168         .name                   = "selftest",
1169         .is_static_object       = is_static_object,
1170         .fixup_init             = fixup_init,
1171         .fixup_activate         = fixup_activate,
1172         .fixup_destroy          = fixup_destroy,
1173         .fixup_free             = fixup_free,
1174 };
1175
1176 static __initdata struct self_test obj = { .static_init = 0 };
1177
1178 static void __init debug_objects_selftest(void)
1179 {
1180         int fixups, oldfixups, warnings, oldwarnings;
1181         unsigned long flags;
1182
1183         local_irq_save(flags);
1184
1185         fixups = oldfixups = debug_objects_fixups;
1186         warnings = oldwarnings = debug_objects_warnings;
1187         descr_test = &descr_type_test;
1188
1189         debug_object_init(&obj, &descr_type_test);
1190         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1191                 goto out;
1192         debug_object_activate(&obj, &descr_type_test);
1193         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1194                 goto out;
1195         debug_object_activate(&obj, &descr_type_test);
1196         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1197                 goto out;
1198         debug_object_deactivate(&obj, &descr_type_test);
1199         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1200                 goto out;
1201         debug_object_destroy(&obj, &descr_type_test);
1202         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1203                 goto out;
1204         debug_object_init(&obj, &descr_type_test);
1205         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1206                 goto out;
1207         debug_object_activate(&obj, &descr_type_test);
1208         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1209                 goto out;
1210         debug_object_deactivate(&obj, &descr_type_test);
1211         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1212                 goto out;
1213         debug_object_free(&obj, &descr_type_test);
1214         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1215                 goto out;
1216
1217         obj.static_init = 1;
1218         debug_object_activate(&obj, &descr_type_test);
1219         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1220                 goto out;
1221         debug_object_init(&obj, &descr_type_test);
1222         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1223                 goto out;
1224         debug_object_free(&obj, &descr_type_test);
1225         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1226                 goto out;
1227
1228 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1229         debug_object_init(&obj, &descr_type_test);
1230         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1231                 goto out;
1232         debug_object_activate(&obj, &descr_type_test);
1233         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1234                 goto out;
1235         __debug_check_no_obj_freed(&obj, sizeof(obj));
1236         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1237                 goto out;
1238 #endif
1239         pr_info("selftest passed\n");
1240
1241 out:
1242         debug_objects_fixups = oldfixups;
1243         debug_objects_warnings = oldwarnings;
1244         descr_test = NULL;
1245
1246         local_irq_restore(flags);
1247 }
1248 #else
1249 static inline void debug_objects_selftest(void) { }
1250 #endif
1251
1252 /*
1253  * Called during early boot to initialize the hash buckets and link
1254  * the static object pool objects into the poll list. After this call
1255  * the object tracker is fully operational.
1256  */
1257 void __init debug_objects_early_init(void)
1258 {
1259         int i;
1260
1261         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1262                 raw_spin_lock_init(&obj_hash[i].lock);
1263
1264         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1265                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1266 }
1267
1268 /*
1269  * Convert the statically allocated objects to dynamic ones:
1270  */
1271 static int __init debug_objects_replace_static_objects(void)
1272 {
1273         struct debug_bucket *db = obj_hash;
1274         struct hlist_node *tmp;
1275         struct debug_obj *obj, *new;
1276         HLIST_HEAD(objects);
1277         int i, cnt = 0;
1278
1279         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1280                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1281                 if (!obj)
1282                         goto free;
1283                 hlist_add_head(&obj->node, &objects);
1284         }
1285
1286         /*
1287          * debug_objects_mem_init() is now called early that only one CPU is up
1288          * and interrupts have been disabled, so it is safe to replace the
1289          * active object references.
1290          */
1291
1292         /* Remove the statically allocated objects from the pool */
1293         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1294                 hlist_del(&obj->node);
1295         /* Move the allocated objects to the pool */
1296         hlist_move_list(&objects, &obj_pool);
1297
1298         /* Replace the active object references */
1299         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1300                 hlist_move_list(&db->list, &objects);
1301
1302                 hlist_for_each_entry(obj, &objects, node) {
1303                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1304                         hlist_del(&new->node);
1305                         /* copy object data */
1306                         *new = *obj;
1307                         hlist_add_head(&new->node, &db->list);
1308                         cnt++;
1309                 }
1310         }
1311
1312         pr_debug("%d of %d active objects replaced\n",
1313                  cnt, obj_pool_used);
1314         return 0;
1315 free:
1316         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1317                 hlist_del(&obj->node);
1318                 kmem_cache_free(obj_cache, obj);
1319         }
1320         return -ENOMEM;
1321 }
1322
1323 /*
1324  * Called after the kmem_caches are functional to setup a dedicated
1325  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1326  * prevents that the debug code is called on kmem_cache_free() for the
1327  * debug tracker objects to avoid recursive calls.
1328  */
1329 void __init debug_objects_mem_init(void)
1330 {
1331         int cpu, extras;
1332
1333         if (!debug_objects_enabled)
1334                 return;
1335
1336         /*
1337          * Initialize the percpu object pools
1338          *
1339          * Initialization is not strictly necessary, but was done for
1340          * completeness.
1341          */
1342         for_each_possible_cpu(cpu)
1343                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1344
1345         obj_cache = kmem_cache_create("debug_objects_cache",
1346                                       sizeof (struct debug_obj), 0,
1347                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1348                                       NULL);
1349
1350         if (!obj_cache || debug_objects_replace_static_objects()) {
1351                 debug_objects_enabled = 0;
1352                 kmem_cache_destroy(obj_cache);
1353                 pr_warn("out of memory.\n");
1354         } else
1355                 debug_objects_selftest();
1356
1357         /*
1358          * Increase the thresholds for allocating and freeing objects
1359          * according to the number of possible CPUs available in the system.
1360          */
1361         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1362         debug_objects_pool_size += extras;
1363         debug_objects_pool_min_level += extras;
1364 }