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_HIGH | __GFP_NOWARN;
 132         struct debug_obj *obj;
 133         unsigned long flags;
 134
 135         if (likely(READ_ONCE(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          * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
 143          * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
 144          * sections.
 145          */
 146         while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
 147                 raw_spin_lock_irqsave(&pool_lock, flags);
 148                 /*
 149                  * Recheck with the lock held as the worker thread might have
 150                  * won the race and freed the global free list already.
 151                  */
 152                 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 153                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 154                         hlist_del(&obj->node);
 155                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 156                         hlist_add_head(&obj->node, &obj_pool);
 157                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 158                 }
 159                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 160         }
 161
 162         if (unlikely(!obj_cache))
 163                 return;
 164
 165         while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
 166                 struct debug_obj *new[ODEBUG_BATCH_SIZE];
 167                 int cnt;
 168
 169                 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
 170                         new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
 171                         if (!new[cnt])
 172                                 break;
 173                 }
 174                 if (!cnt)
 175                         return;
 176
 177                 raw_spin_lock_irqsave(&pool_lock, flags);
 178                 while (cnt) {
 179                         hlist_add_head(&new[--cnt]->node, &obj_pool);
 180                         debug_objects_allocated++;
 181                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 182                 }
 183                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 184         }
 185 }
 186
 187 /*
 188  * Lookup an object in the hash bucket.
 189  */
 190 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 191 {
 192         struct debug_obj *obj;
 193         int cnt = 0;
 194
 195         hlist_for_each_entry(obj, &b->list, node) {
 196                 cnt++;
 197                 if (obj->object == addr)
 198                         return obj;
 199         }
 200         if (cnt > debug_objects_maxchain)
 201                 debug_objects_maxchain = cnt;
 202
 203         return NULL;
 204 }
 205
 206 /*
 207  * Allocate a new object from the hlist
 208  */
 209 static struct debug_obj *__alloc_object(struct hlist_head *list)
 210 {
 211         struct debug_obj *obj = NULL;
 212
 213         if (list->first) {
 214                 obj = hlist_entry(list->first, typeof(*obj), node);
 215                 hlist_del(&obj->node);
 216         }
 217
 218         return obj;
 219 }
 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                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 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                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 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                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 313                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 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                 WRITE_ONCE(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                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 379                 hlist_add_head(&obj->node, &obj_to_free);
 380                 if (lookahead_count) {
 381                         WRITE_ONCE(obj_nr_tofree, 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                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 400                                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 401                         }
 402                 }
 403         } else {
 404                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 405                 hlist_add_head(&obj->node, &obj_pool);
 406                 if (lookahead_count) {
 407                         WRITE_ONCE(obj_pool_free, 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 (!READ_ONCE(obj_freeing) && READ_ONCE(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         /*
 478          * Don't report if lookup_object_or_alloc() by the current thread
 479          * failed because lookup_object_or_alloc()/debug_objects_oom() by a
 480          * concurrent thread turned off debug_objects_enabled and cleared
 481          * the hash buckets.
 482          */
 483         if (!debug_objects_enabled)
 484                 return;
 485
 486         if (limit < 5 && descr != descr_test) {
 487                 void *hint = descr->debug_hint ?
 488                         descr->debug_hint(obj->object) : NULL;
 489                 limit++;
 490                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 491                                  "object type: %s hint: %pS\n",
 492                         msg, obj_states[obj->state], obj->astate,
 493                         descr->name, hint);
 494         }
 495         debug_objects_warnings++;
 496 }
 497
 498 /*
 499  * Try to repair the damage, so we have a better chance to get useful
 500  * debug output.
 501  */
 502 static bool
 503 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 504                    void * addr, enum debug_obj_state state)
 505 {
 506         if (fixup && fixup(addr, state)) {
 507                 debug_objects_fixups++;
 508                 return true;
 509         }
 510         return false;
 511 }
 512
 513 static void debug_object_is_on_stack(void *addr, int onstack)
 514 {
 515         int is_on_stack;
 516         static int limit;
 517
 518         if (limit > 4)
 519                 return;
 520
 521         is_on_stack = object_is_on_stack(addr);
 522         if (is_on_stack == onstack)
 523                 return;
 524
 525         limit++;
 526         if (is_on_stack)
 527                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 528                          task_stack_page(current));
 529         else
 530                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 531                          task_stack_page(current));
 532
 533         WARN_ON(1);
 534 }
 535
 536 static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
 537                                                 struct debug_obj_descr *descr,
 538                                                 bool onstack, bool alloc_ifstatic)
 539 {
 540         struct debug_obj *obj = lookup_object(addr, b);
 541         enum debug_obj_state state = ODEBUG_STATE_NONE;
 542
 543         if (likely(obj))
 544                 return obj;
 545
 546         /*
 547          * debug_object_init() unconditionally allocates untracked
 548          * objects. It does not matter whether it is a static object or
 549          * not.
 550          *
 551          * debug_object_assert_init() and debug_object_activate() allow
 552          * allocation only if the descriptor callback confirms that the
 553          * object is static and considered initialized. For non-static
 554          * objects the allocation needs to be done from the fixup callback.
 555          */
 556         if (unlikely(alloc_ifstatic)) {
 557                 if (!descr->is_static_object || !descr->is_static_object(addr))
 558                         return ERR_PTR(-ENOENT);
 559                 /* Statically allocated objects are considered initialized */
 560                 state = ODEBUG_STATE_INIT;
 561         }
 562
 563         obj = alloc_object(addr, b, descr);
 564         if (likely(obj)) {
 565                 obj->state = state;
 566                 debug_object_is_on_stack(addr, onstack);
 567                 return obj;
 568         }
 569
 570         /* Out of memory. Do the cleanup outside of the locked region */
 571         debug_objects_enabled = 0;
 572         return NULL;
 573 }
 574
 575 static void debug_objects_fill_pool(void)
 576 {
 577         /*
 578          * On RT enabled kernels the pool refill must happen in preemptible
 579          * context:
 580          */
 581         if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
 582                 fill_pool();
 583 }
 584
 585 static void
 586 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 587 {
 588         enum debug_obj_state state;
 589         struct debug_bucket *db;
 590         struct debug_obj *obj;
 591         unsigned long flags;
 592
 593         debug_objects_fill_pool();
 594
 595         db = get_bucket((unsigned long) addr);
 596
 597         raw_spin_lock_irqsave(&db->lock, flags);
 598
 599         obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
 600         if (unlikely(!obj)) {
 601                 raw_spin_unlock_irqrestore(&db->lock, flags);
 602                 debug_objects_oom();
 603                 return;
 604         }
 605
 606         switch (obj->state) {
 607         case ODEBUG_STATE_NONE:
 608         case ODEBUG_STATE_INIT:
 609         case ODEBUG_STATE_INACTIVE:
 610                 obj->state = ODEBUG_STATE_INIT;
 611                 break;
 612
 613         case ODEBUG_STATE_ACTIVE:
 614                 state = obj->state;
 615                 raw_spin_unlock_irqrestore(&db->lock, flags);
 616                 debug_print_object(obj, "init");
 617                 debug_object_fixup(descr->fixup_init, addr, state);
 618                 return;
 619
 620         case ODEBUG_STATE_DESTROYED:
 621                 raw_spin_unlock_irqrestore(&db->lock, flags);
 622                 debug_print_object(obj, "init");
 623                 return;
 624         default:
 625                 break;
 626         }
 627
 628         raw_spin_unlock_irqrestore(&db->lock, flags);
 629 }
 630
 631 /**
 632  * debug_object_init - debug checks when an object is initialized
 633  * @addr:       address of the object
 634  * @descr:      pointer to an object specific debug description structure
 635  */
 636 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 637 {
 638         if (!debug_objects_enabled)
 639                 return;
 640
 641         __debug_object_init(addr, descr, 0);
 642 }
 643 EXPORT_SYMBOL_GPL(debug_object_init);
 644
 645 /**
 646  * debug_object_init_on_stack - debug checks when an object on stack is
 647  *                              initialized
 648  * @addr:       address of the object
 649  * @descr:      pointer to an object specific debug description structure
 650  */
 651 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 652 {
 653         if (!debug_objects_enabled)
 654                 return;
 655
 656         __debug_object_init(addr, descr, 1);
 657 }
 658 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 659
 660 /**
 661  * debug_object_activate - debug checks when an object is activated
 662  * @addr:       address of the object
 663  * @descr:      pointer to an object specific debug description structure
 664  * Returns 0 for success, -EINVAL for check failed.
 665  */
 666 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 667 {
 668         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 669         enum debug_obj_state state;
 670         struct debug_bucket *db;
 671         struct debug_obj *obj;
 672         unsigned long flags;
 673         int ret;
 674
 675         if (!debug_objects_enabled)
 676                 return 0;
 677
 678         debug_objects_fill_pool();
 679
 680         db = get_bucket((unsigned long) addr);
 681
 682         raw_spin_lock_irqsave(&db->lock, flags);
 683
 684         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 685         if (likely(!IS_ERR_OR_NULL(obj))) {
 686                 bool print_object = false;
 687
 688                 switch (obj->state) {
 689                 case ODEBUG_STATE_INIT:
 690                 case ODEBUG_STATE_INACTIVE:
 691                         obj->state = ODEBUG_STATE_ACTIVE;
 692                         ret = 0;
 693                         break;
 694
 695                 case ODEBUG_STATE_ACTIVE:
 696                         state = obj->state;
 697                         raw_spin_unlock_irqrestore(&db->lock, flags);
 698                         debug_print_object(obj, "activate");
 699                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 700                         return ret ? 0 : -EINVAL;
 701
 702                 case ODEBUG_STATE_DESTROYED:
 703                         print_object = true;
 704                         ret = -EINVAL;
 705                         break;
 706                 default:
 707                         ret = 0;
 708                         break;
 709                 }
 710                 raw_spin_unlock_irqrestore(&db->lock, flags);
 711                 if (print_object)
 712                         debug_print_object(obj, "activate");
 713                 return ret;
 714         }
 715
 716         raw_spin_unlock_irqrestore(&db->lock, flags);
 717
 718         /* If NULL the allocation has hit OOM */
 719         if (!obj) {
 720                 debug_objects_oom();
 721                 return 0;
 722         }
 723
 724         /* Object is neither static nor tracked. It's not initialized */
 725         debug_print_object(&o, "activate");
 726         ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE);
 727         return ret ? 0 : -EINVAL;
 728 }
 729 EXPORT_SYMBOL_GPL(debug_object_activate);
 730
 731 /**
 732  * debug_object_deactivate - debug checks when an object is deactivated
 733  * @addr:       address of the object
 734  * @descr:      pointer to an object specific debug description structure
 735  */
 736 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 737 {
 738         struct debug_bucket *db;
 739         struct debug_obj *obj;
 740         unsigned long flags;
 741         bool print_object = false;
 742
 743         if (!debug_objects_enabled)
 744                 return;
 745
 746         db = get_bucket((unsigned long) addr);
 747
 748         raw_spin_lock_irqsave(&db->lock, flags);
 749
 750         obj = lookup_object(addr, db);
 751         if (obj) {
 752                 switch (obj->state) {
 753                 case ODEBUG_STATE_INIT:
 754                 case ODEBUG_STATE_INACTIVE:
 755                 case ODEBUG_STATE_ACTIVE:
 756                         if (!obj->astate)
 757                                 obj->state = ODEBUG_STATE_INACTIVE;
 758                         else
 759                                 print_object = true;
 760                         break;
 761
 762                 case ODEBUG_STATE_DESTROYED:
 763                         print_object = true;
 764                         break;
 765                 default:
 766                         break;
 767                 }
 768         }
 769
 770         raw_spin_unlock_irqrestore(&db->lock, flags);
 771         if (!obj) {
 772                 struct debug_obj o = { .object = addr,
 773                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 774                                        .descr = descr };
 775
 776                 debug_print_object(&o, "deactivate");
 777         } else if (print_object) {
 778                 debug_print_object(obj, "deactivate");
 779         }
 780 }
 781 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 782
 783 /**
 784  * debug_object_destroy - debug checks when an object is destroyed
 785  * @addr:       address of the object
 786  * @descr:      pointer to an object specific debug description structure
 787  */
 788 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 789 {
 790         enum debug_obj_state state;
 791         struct debug_bucket *db;
 792         struct debug_obj *obj;
 793         unsigned long flags;
 794         bool print_object = false;
 795
 796         if (!debug_objects_enabled)
 797                 return;
 798
 799         db = get_bucket((unsigned long) addr);
 800
 801         raw_spin_lock_irqsave(&db->lock, flags);
 802
 803         obj = lookup_object(addr, db);
 804         if (!obj)
 805                 goto out_unlock;
 806
 807         switch (obj->state) {
 808         case ODEBUG_STATE_NONE:
 809         case ODEBUG_STATE_INIT:
 810         case ODEBUG_STATE_INACTIVE:
 811                 obj->state = ODEBUG_STATE_DESTROYED;
 812                 break;
 813         case ODEBUG_STATE_ACTIVE:
 814                 state = obj->state;
 815                 raw_spin_unlock_irqrestore(&db->lock, flags);
 816                 debug_print_object(obj, "destroy");
 817                 debug_object_fixup(descr->fixup_destroy, addr, state);
 818                 return;
 819
 820         case ODEBUG_STATE_DESTROYED:
 821                 print_object = true;
 822                 break;
 823         default:
 824                 break;
 825         }
 826 out_unlock:
 827         raw_spin_unlock_irqrestore(&db->lock, flags);
 828         if (print_object)
 829                 debug_print_object(obj, "destroy");
 830 }
 831 EXPORT_SYMBOL_GPL(debug_object_destroy);
 832
 833 /**
 834  * debug_object_free - debug checks when an object is freed
 835  * @addr:       address of the object
 836  * @descr:      pointer to an object specific debug description structure
 837  */
 838 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 839 {
 840         enum debug_obj_state state;
 841         struct debug_bucket *db;
 842         struct debug_obj *obj;
 843         unsigned long flags;
 844
 845         if (!debug_objects_enabled)
 846                 return;
 847
 848         db = get_bucket((unsigned long) addr);
 849
 850         raw_spin_lock_irqsave(&db->lock, flags);
 851
 852         obj = lookup_object(addr, db);
 853         if (!obj)
 854                 goto out_unlock;
 855
 856         switch (obj->state) {
 857         case ODEBUG_STATE_ACTIVE:
 858                 state = obj->state;
 859                 raw_spin_unlock_irqrestore(&db->lock, flags);
 860                 debug_print_object(obj, "free");
 861                 debug_object_fixup(descr->fixup_free, addr, state);
 862                 return;
 863         default:
 864                 hlist_del(&obj->node);
 865                 raw_spin_unlock_irqrestore(&db->lock, flags);
 866                 free_object(obj);
 867                 return;
 868         }
 869 out_unlock:
 870         raw_spin_unlock_irqrestore(&db->lock, flags);
 871 }
 872 EXPORT_SYMBOL_GPL(debug_object_free);
 873
 874 /**
 875  * debug_object_assert_init - debug checks when object should be init-ed
 876  * @addr:       address of the object
 877  * @descr:      pointer to an object specific debug description structure
 878  */
 879 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 880 {
 881         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 882         struct debug_bucket *db;
 883         struct debug_obj *obj;
 884         unsigned long flags;
 885
 886         if (!debug_objects_enabled)
 887                 return;
 888
 889         debug_objects_fill_pool();
 890
 891         db = get_bucket((unsigned long) addr);
 892
 893         raw_spin_lock_irqsave(&db->lock, flags);
 894         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 895         raw_spin_unlock_irqrestore(&db->lock, flags);
 896         if (likely(!IS_ERR_OR_NULL(obj)))
 897                 return;
 898
 899         /* If NULL the allocation has hit OOM */
 900         if (!obj) {
 901                 debug_objects_oom();
 902                 return;
 903         }
 904
 905         /* Object is neither tracked nor static. It's not initialized. */
 906         debug_print_object(&o, "assert_init");
 907         debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
 908 }
 909 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 910
 911 /**
 912  * debug_object_active_state - debug checks object usage state machine
 913  * @addr:       address of the object
 914  * @descr:      pointer to an object specific debug description structure
 915  * @expect:     expected state
 916  * @next:       state to move to if expected state is found
 917  */
 918 void
 919 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 920                           unsigned int expect, unsigned int next)
 921 {
 922         struct debug_bucket *db;
 923         struct debug_obj *obj;
 924         unsigned long flags;
 925         bool print_object = false;
 926
 927         if (!debug_objects_enabled)
 928                 return;
 929
 930         db = get_bucket((unsigned long) addr);
 931
 932         raw_spin_lock_irqsave(&db->lock, flags);
 933
 934         obj = lookup_object(addr, db);
 935         if (obj) {
 936                 switch (obj->state) {
 937                 case ODEBUG_STATE_ACTIVE:
 938                         if (obj->astate == expect)
 939                                 obj->astate = next;
 940                         else
 941                                 print_object = true;
 942                         break;
 943
 944                 default:
 945                         print_object = true;
 946                         break;
 947                 }
 948         }
 949
 950         raw_spin_unlock_irqrestore(&db->lock, flags);
 951         if (!obj) {
 952                 struct debug_obj o = { .object = addr,
 953                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 954                                        .descr = descr };
 955
 956                 debug_print_object(&o, "active_state");
 957         } else if (print_object) {
 958                 debug_print_object(obj, "active_state");
 959         }
 960 }
 961 EXPORT_SYMBOL_GPL(debug_object_active_state);
 962
 963 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 964 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 965 {
 966         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 967         struct debug_obj_descr *descr;
 968         enum debug_obj_state state;
 969         struct debug_bucket *db;
 970         struct hlist_node *tmp;
 971         struct debug_obj *obj;
 972         int cnt, objs_checked = 0;
 973
 974         saddr = (unsigned long) address;
 975         eaddr = saddr + size;
 976         paddr = saddr & ODEBUG_CHUNK_MASK;
 977         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 978         chunks >>= ODEBUG_CHUNK_SHIFT;
 979
 980         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 981                 db = get_bucket(paddr);
 982
 983 repeat:
 984                 cnt = 0;
 985                 raw_spin_lock_irqsave(&db->lock, flags);
 986                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 987                         cnt++;
 988                         oaddr = (unsigned long) obj->object;
 989                         if (oaddr < saddr || oaddr >= eaddr)
 990                                 continue;
 991
 992                         switch (obj->state) {
 993                         case ODEBUG_STATE_ACTIVE:
 994                                 descr = obj->descr;
 995                                 state = obj->state;
 996                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 997                                 debug_print_object(obj, "free");
 998                                 debug_object_fixup(descr->fixup_free,
 999                                                    (void *) oaddr, state);
1000                                 goto repeat;
1001                         default:
1002                                 hlist_del(&obj->node);
1003                                 __free_object(obj);
1004                                 break;
1005                         }
1006                 }
1007                 raw_spin_unlock_irqrestore(&db->lock, flags);
1008
1009                 if (cnt > debug_objects_maxchain)
1010                         debug_objects_maxchain = cnt;
1011
1012                 objs_checked += cnt;
1013         }
1014
1015         if (objs_checked > debug_objects_maxchecked)
1016                 debug_objects_maxchecked = objs_checked;
1017
1018         /* Schedule work to actually kmem_cache_free() objects */
1019         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1020                 WRITE_ONCE(obj_freeing, true);
1021                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1022         }
1023 }
1024
1025 void debug_check_no_obj_freed(const void *address, unsigned long size)
1026 {
1027         if (debug_objects_enabled)
1028                 __debug_check_no_obj_freed(address, size);
1029 }
1030 #endif
1031
1032 #ifdef CONFIG_DEBUG_FS
1033
1034 static int debug_stats_show(struct seq_file *m, void *v)
1035 {
1036         int cpu, obj_percpu_free = 0;
1037
1038         for_each_possible_cpu(cpu)
1039                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1040
1041         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1042         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1043         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1044         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1045         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1046         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1047         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1048         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1049         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1050         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1051         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1052         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1053         return 0;
1054 }
1055
1056 static int debug_stats_open(struct inode *inode, struct file *filp)
1057 {
1058         return single_open(filp, debug_stats_show, NULL);
1059 }
1060
1061 static const struct file_operations debug_stats_fops = {
1062         .open           = debug_stats_open,
1063         .read           = seq_read,
1064         .llseek         = seq_lseek,
1065         .release        = single_release,
1066 };
1067
1068 static int __init debug_objects_init_debugfs(void)
1069 {
1070         struct dentry *dbgdir;
1071
1072         if (!debug_objects_enabled)
1073                 return 0;
1074
1075         dbgdir = debugfs_create_dir("debug_objects", NULL);
1076
1077         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1078
1079         return 0;
1080 }
1081 __initcall(debug_objects_init_debugfs);
1082
1083 #else
1084 static inline void debug_objects_init_debugfs(void) { }
1085 #endif
1086
1087 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1088
1089 /* Random data structure for the self test */
1090 struct self_test {
1091         unsigned long   dummy1[6];
1092         int             static_init;
1093         unsigned long   dummy2[3];
1094 };
1095
1096 static __initdata struct debug_obj_descr descr_type_test;
1097
1098 static bool __init is_static_object(void *addr)
1099 {
1100         struct self_test *obj = addr;
1101
1102         return obj->static_init;
1103 }
1104
1105 /*
1106  * fixup_init is called when:
1107  * - an active object is initialized
1108  */
1109 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1110 {
1111         struct self_test *obj = addr;
1112
1113         switch (state) {
1114         case ODEBUG_STATE_ACTIVE:
1115                 debug_object_deactivate(obj, &descr_type_test);
1116                 debug_object_init(obj, &descr_type_test);
1117                 return true;
1118         default:
1119                 return false;
1120         }
1121 }
1122
1123 /*
1124  * fixup_activate is called when:
1125  * - an active object is activated
1126  * - an unknown non-static object is activated
1127  */
1128 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1129 {
1130         struct self_test *obj = addr;
1131
1132         switch (state) {
1133         case ODEBUG_STATE_NOTAVAILABLE:
1134                 return true;
1135         case ODEBUG_STATE_ACTIVE:
1136                 debug_object_deactivate(obj, &descr_type_test);
1137                 debug_object_activate(obj, &descr_type_test);
1138                 return true;
1139
1140         default:
1141                 return false;
1142         }
1143 }
1144
1145 /*
1146  * fixup_destroy is called when:
1147  * - an active object is destroyed
1148  */
1149 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1150 {
1151         struct self_test *obj = addr;
1152
1153         switch (state) {
1154         case ODEBUG_STATE_ACTIVE:
1155                 debug_object_deactivate(obj, &descr_type_test);
1156                 debug_object_destroy(obj, &descr_type_test);
1157                 return true;
1158         default:
1159                 return false;
1160         }
1161 }
1162
1163 /*
1164  * fixup_free is called when:
1165  * - an active object is freed
1166  */
1167 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1168 {
1169         struct self_test *obj = addr;
1170
1171         switch (state) {
1172         case ODEBUG_STATE_ACTIVE:
1173                 debug_object_deactivate(obj, &descr_type_test);
1174                 debug_object_free(obj, &descr_type_test);
1175                 return true;
1176         default:
1177                 return false;
1178         }
1179 }
1180
1181 static int __init
1182 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1183 {
1184         struct debug_bucket *db;
1185         struct debug_obj *obj;
1186         unsigned long flags;
1187         int res = -EINVAL;
1188
1189         db = get_bucket((unsigned long) addr);
1190
1191         raw_spin_lock_irqsave(&db->lock, flags);
1192
1193         obj = lookup_object(addr, db);
1194         if (!obj && state != ODEBUG_STATE_NONE) {
1195                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1196                 goto out;
1197         }
1198         if (obj && obj->state != state) {
1199                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1200                        obj->state, state);
1201                 goto out;
1202         }
1203         if (fixups != debug_objects_fixups) {
1204                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1205                        fixups, debug_objects_fixups);
1206                 goto out;
1207         }
1208         if (warnings != debug_objects_warnings) {
1209                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1210                        warnings, debug_objects_warnings);
1211                 goto out;
1212         }
1213         res = 0;
1214 out:
1215         raw_spin_unlock_irqrestore(&db->lock, flags);
1216         if (res)
1217                 debug_objects_enabled = 0;
1218         return res;
1219 }
1220
1221 static __initdata struct debug_obj_descr descr_type_test = {
1222         .name                   = "selftest",
1223         .is_static_object       = is_static_object,
1224         .fixup_init             = fixup_init,
1225         .fixup_activate         = fixup_activate,
1226         .fixup_destroy          = fixup_destroy,
1227         .fixup_free             = fixup_free,
1228 };
1229
1230 static __initdata struct self_test obj = { .static_init = 0 };
1231
1232 static void __init debug_objects_selftest(void)
1233 {
1234         int fixups, oldfixups, warnings, oldwarnings;
1235         unsigned long flags;
1236
1237         local_irq_save(flags);
1238
1239         fixups = oldfixups = debug_objects_fixups;
1240         warnings = oldwarnings = debug_objects_warnings;
1241         descr_test = &descr_type_test;
1242
1243         debug_object_init(&obj, &descr_type_test);
1244         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1245                 goto out;
1246         debug_object_activate(&obj, &descr_type_test);
1247         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1248                 goto out;
1249         debug_object_activate(&obj, &descr_type_test);
1250         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1251                 goto out;
1252         debug_object_deactivate(&obj, &descr_type_test);
1253         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1254                 goto out;
1255         debug_object_destroy(&obj, &descr_type_test);
1256         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1257                 goto out;
1258         debug_object_init(&obj, &descr_type_test);
1259         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1260                 goto out;
1261         debug_object_activate(&obj, &descr_type_test);
1262         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1263                 goto out;
1264         debug_object_deactivate(&obj, &descr_type_test);
1265         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1266                 goto out;
1267         debug_object_free(&obj, &descr_type_test);
1268         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1269                 goto out;
1270
1271         obj.static_init = 1;
1272         debug_object_activate(&obj, &descr_type_test);
1273         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1274                 goto out;
1275         debug_object_init(&obj, &descr_type_test);
1276         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1277                 goto out;
1278         debug_object_free(&obj, &descr_type_test);
1279         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1280                 goto out;
1281
1282 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1283         debug_object_init(&obj, &descr_type_test);
1284         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1285                 goto out;
1286         debug_object_activate(&obj, &descr_type_test);
1287         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1288                 goto out;
1289         __debug_check_no_obj_freed(&obj, sizeof(obj));
1290         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1291                 goto out;
1292 #endif
1293         pr_info("selftest passed\n");
1294
1295 out:
1296         debug_objects_fixups = oldfixups;
1297         debug_objects_warnings = oldwarnings;
1298         descr_test = NULL;
1299
1300         local_irq_restore(flags);
1301 }
1302 #else
1303 static inline void debug_objects_selftest(void) { }
1304 #endif
1305
1306 /*
1307  * Called during early boot to initialize the hash buckets and link
1308  * the static object pool objects into the poll list. After this call
1309  * the object tracker is fully operational.
1310  */
1311 void __init debug_objects_early_init(void)
1312 {
1313         int i;
1314
1315         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1316                 raw_spin_lock_init(&obj_hash[i].lock);
1317
1318         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1319                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1320 }
1321
1322 /*
1323  * Convert the statically allocated objects to dynamic ones:
1324  */
1325 static int __init debug_objects_replace_static_objects(void)
1326 {
1327         struct debug_bucket *db = obj_hash;
1328         struct hlist_node *tmp;
1329         struct debug_obj *obj, *new;
1330         HLIST_HEAD(objects);
1331         int i, cnt = 0;
1332
1333         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1334                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1335                 if (!obj)
1336                         goto free;
1337                 hlist_add_head(&obj->node, &objects);
1338         }
1339
1340         /*
1341          * debug_objects_mem_init() is now called early that only one CPU is up
1342          * and interrupts have been disabled, so it is safe to replace the
1343          * active object references.
1344          */
1345
1346         /* Remove the statically allocated objects from the pool */
1347         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1348                 hlist_del(&obj->node);
1349         /* Move the allocated objects to the pool */
1350         hlist_move_list(&objects, &obj_pool);
1351
1352         /* Replace the active object references */
1353         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1354                 hlist_move_list(&db->list, &objects);
1355
1356                 hlist_for_each_entry(obj, &objects, node) {
1357                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1358                         hlist_del(&new->node);
1359                         /* copy object data */
1360                         *new = *obj;
1361                         hlist_add_head(&new->node, &db->list);
1362                         cnt++;
1363                 }
1364         }
1365
1366         pr_debug("%d of %d active objects replaced\n",
1367                  cnt, obj_pool_used);
1368         return 0;
1369 free:
1370         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1371                 hlist_del(&obj->node);
1372                 kmem_cache_free(obj_cache, obj);
1373         }
1374         return -ENOMEM;
1375 }
1376
1377 /*
1378  * Called after the kmem_caches are functional to setup a dedicated
1379  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1380  * prevents that the debug code is called on kmem_cache_free() for the
1381  * debug tracker objects to avoid recursive calls.
1382  */
1383 void __init debug_objects_mem_init(void)
1384 {
1385         int cpu, extras;
1386
1387         if (!debug_objects_enabled)
1388                 return;
1389
1390         /*
1391          * Initialize the percpu object pools
1392          *
1393          * Initialization is not strictly necessary, but was done for
1394          * completeness.
1395          */
1396         for_each_possible_cpu(cpu)
1397                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1398
1399         obj_cache = kmem_cache_create("debug_objects_cache",
1400                                       sizeof (struct debug_obj), 0,
1401                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1402                                       NULL);
1403
1404         if (!obj_cache || debug_objects_replace_static_objects()) {
1405                 debug_objects_enabled = 0;
1406                 kmem_cache_destroy(obj_cache);
1407                 pr_warn("out of memory.\n");
1408         } else
1409                 debug_objects_selftest();
1410
1411         /*
1412          * Increase the thresholds for allocating and freeing objects
1413          * according to the number of possible CPUs available in the system.
1414          */
1415         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1416         debug_objects_pool_size += extras;
1417         debug_objects_pool_min_level += extras;
1418 }