lib/debugobjects.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Generic infrastructure for lifetime debugging of objects.
   4  *
   5  * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
   6  */
   7
   8 #define pr_fmt(fmt) "ODEBUG: " fmt
   9
  10 #include <linux/debugobjects.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/sched.h>
  13 #include <linux/sched/task_stack.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/debugfs.h>
  16 #include <linux/slab.h>
  17 #include <linux/hash.h>
  18 #include <linux/kmemleak.h>
  19 #include <linux/cpu.h>
  20
  21 #define ODEBUG_HASH_BITS        14
  22 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  23
  24 #define ODEBUG_POOL_SIZE        1024
  25 #define ODEBUG_POOL_MIN_LEVEL   256
  26 #define ODEBUG_POOL_PERCPU_SIZE 64
  27 #define ODEBUG_BATCH_SIZE       16
  28
  29 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  30 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  31 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  32
  33 /*
  34  * We limit the freeing of debug objects via workqueue at a maximum
  35  * frequency of 10Hz and about 1024 objects for each freeing operation.
  36  * So it is freeing at most 10k debug objects per second.
  37  */
  38 #define ODEBUG_FREE_WORK_MAX    1024
  39 #define ODEBUG_FREE_WORK_DELAY  DIV_ROUND_UP(HZ, 10)
  40
  41 struct debug_bucket {
  42         struct hlist_head       list;
  43         raw_spinlock_t          lock;
  44 };
  45
  46 /*
  47  * Debug object percpu free list
  48  * Access is protected by disabling irq
  49  */
  50 struct debug_percpu_free {
  51         struct hlist_head       free_objs;
  52         int                     obj_free;
  53 };
  54
  55 static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
  56
  57 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  58
  59 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  60
  61 static DEFINE_RAW_SPINLOCK(pool_lock);
  62
  63 static HLIST_HEAD(obj_pool);
  64 static HLIST_HEAD(obj_to_free);
  65
  66 /*
  67  * Because of the presence of percpu free pools, obj_pool_free will
  68  * under-count those in the percpu free pools. Similarly, obj_pool_used
  69  * will over-count those in the percpu free pools. Adjustments will be
  70  * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
  71  * can be off.
  72  */
  73 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  74 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  75 static int                      obj_pool_used;
  76 static int                      obj_pool_max_used;
  77 static bool                     obj_freeing;
  78 /* The number of objs on the global free list */
  79 static int                      obj_nr_tofree;
  80
  81 static int                      debug_objects_maxchain __read_mostly;
  82 static int __maybe_unused       debug_objects_maxchecked __read_mostly;
  83 static int                      debug_objects_fixups __read_mostly;
  84 static int                      debug_objects_warnings __read_mostly;
  85 static int                      debug_objects_enabled __read_mostly
  86                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  87 static int                      debug_objects_pool_size __read_mostly
  88                                 = ODEBUG_POOL_SIZE;
  89 static int                      debug_objects_pool_min_level __read_mostly
  90                                 = ODEBUG_POOL_MIN_LEVEL;
  91 static const struct debug_obj_descr *descr_test  __read_mostly;
  92 static struct kmem_cache        *obj_cache __read_mostly;
  93
  94 /*
  95  * Track numbers of kmem_cache_alloc()/free() calls done.
  96  */
  97 static int                      debug_objects_allocated;
  98 static int                      debug_objects_freed;
  99
 100 static void free_obj_work(struct work_struct *work);
 101 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
 102
 103 static int __init enable_object_debug(char *str)
 104 {
 105         debug_objects_enabled = 1;
 106         return 0;
 107 }
 108
 109 static int __init disable_object_debug(char *str)
 110 {
 111         debug_objects_enabled = 0;
 112         return 0;
 113 }
 114
 115 early_param("debug_objects", enable_object_debug);
 116 early_param("no_debug_objects", disable_object_debug);
 117
 118 static const char *obj_states[ODEBUG_STATE_MAX] = {
 119         [ODEBUG_STATE_NONE]             = "none",
 120         [ODEBUG_STATE_INIT]             = "initialized",
 121         [ODEBUG_STATE_INACTIVE]         = "inactive",
 122         [ODEBUG_STATE_ACTIVE]           = "active",
 123         [ODEBUG_STATE_DESTROYED]        = "destroyed",
 124         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
 125 };
 126
 127 static void fill_pool(void)
 128 {
 129         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
 130         struct debug_obj *obj;
 131         unsigned long flags;
 132
 133         if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
 134                 return;
 135
 136         /*
 137          * Reuse objs from the global free list; they will be reinitialized
 138          * when allocating.
 139          *
 140          * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
 141          * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
 142          * sections.
 143          */
 144         while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
 145                 raw_spin_lock_irqsave(&pool_lock, flags);
 146                 /*
 147                  * Recheck with the lock held as the worker thread might have
 148                  * won the race and freed the global free list already.
 149                  */
 150                 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 151                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 152                         hlist_del(&obj->node);
 153                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 154                         hlist_add_head(&obj->node, &obj_pool);
 155                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 156                 }
 157                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 158         }
 159
 160         if (unlikely(!obj_cache))
 161                 return;
 162
 163         while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
 164                 struct debug_obj *new[ODEBUG_BATCH_SIZE];
 165                 int cnt;
 166
 167                 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
 168                         new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
 169                         if (!new[cnt])
 170                                 break;
 171                 }
 172                 if (!cnt)
 173                         return;
 174
 175                 raw_spin_lock_irqsave(&pool_lock, flags);
 176                 while (cnt) {
 177                         hlist_add_head(&new[--cnt]->node, &obj_pool);
 178                         debug_objects_allocated++;
 179                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 180                 }
 181                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 182         }
 183 }
 184
 185 /*
 186  * Lookup an object in the hash bucket.
 187  */
 188 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 189 {
 190         struct debug_obj *obj;
 191         int cnt = 0;
 192
 193         hlist_for_each_entry(obj, &b->list, node) {
 194                 cnt++;
 195                 if (obj->object == addr)
 196                         return obj;
 197         }
 198         if (cnt > debug_objects_maxchain)
 199                 debug_objects_maxchain = cnt;
 200
 201         return NULL;
 202 }
 203
 204 /*
 205  * Allocate a new object from the hlist
 206  */
 207 static struct debug_obj *__alloc_object(struct hlist_head *list)
 208 {
 209         struct debug_obj *obj = NULL;
 210
 211         if (list->first) {
 212                 obj = hlist_entry(list->first, typeof(*obj), node);
 213                 hlist_del(&obj->node);
 214         }
 215
 216         return obj;
 217 }
 218
 219 static struct debug_obj *
 220 alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
 221 {
 222         struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 223         struct debug_obj *obj;
 224
 225         if (likely(obj_cache)) {
 226                 obj = __alloc_object(&percpu_pool->free_objs);
 227                 if (obj) {
 228                         percpu_pool->obj_free--;
 229                         goto init_obj;
 230                 }
 231         }
 232
 233         raw_spin_lock(&pool_lock);
 234         obj = __alloc_object(&obj_pool);
 235         if (obj) {
 236                 obj_pool_used++;
 237                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 238
 239                 /*
 240                  * Looking ahead, allocate one batch of debug objects and
 241                  * put them into the percpu free pool.
 242                  */
 243                 if (likely(obj_cache)) {
 244                         int i;
 245
 246                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 247                                 struct debug_obj *obj2;
 248
 249                                 obj2 = __alloc_object(&obj_pool);
 250                                 if (!obj2)
 251                                         break;
 252                                 hlist_add_head(&obj2->node,
 253                                                &percpu_pool->free_objs);
 254                                 percpu_pool->obj_free++;
 255                                 obj_pool_used++;
 256                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 257                         }
 258                 }
 259
 260                 if (obj_pool_used > obj_pool_max_used)
 261                         obj_pool_max_used = obj_pool_used;
 262
 263                 if (obj_pool_free < obj_pool_min_free)
 264                         obj_pool_min_free = obj_pool_free;
 265         }
 266         raw_spin_unlock(&pool_lock);
 267
 268 init_obj:
 269         if (obj) {
 270                 obj->object = addr;
 271                 obj->descr  = descr;
 272                 obj->state  = ODEBUG_STATE_NONE;
 273                 obj->astate = 0;
 274                 hlist_add_head(&obj->node, &b->list);
 275         }
 276         return obj;
 277 }
 278
 279 /*
 280  * workqueue function to free objects.
 281  *
 282  * To reduce contention on the global pool_lock, the actual freeing of
 283  * debug objects will be delayed if the pool_lock is busy.
 284  */
 285 static void free_obj_work(struct work_struct *work)
 286 {
 287         struct hlist_node *tmp;
 288         struct debug_obj *obj;
 289         unsigned long flags;
 290         HLIST_HEAD(tofree);
 291
 292         WRITE_ONCE(obj_freeing, false);
 293         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 294                 return;
 295
 296         if (obj_pool_free >= debug_objects_pool_size)
 297                 goto free_objs;
 298
 299         /*
 300          * The objs on the pool list might be allocated before the work is
 301          * run, so recheck if pool list it full or not, if not fill pool
 302          * list from the global free list. As it is likely that a workload
 303          * may be gearing up to use more and more objects, don't free any
 304          * of them until the next round.
 305          */
 306         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 307                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 308                 hlist_del(&obj->node);
 309                 hlist_add_head(&obj->node, &obj_pool);
 310                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 311                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 312         }
 313         raw_spin_unlock_irqrestore(&pool_lock, flags);
 314         return;
 315
 316 free_objs:
 317         /*
 318          * Pool list is already full and there are still objs on the free
 319          * list. Move remaining free objs to a temporary list to free the
 320          * memory outside the pool_lock held region.
 321          */
 322         if (obj_nr_tofree) {
 323                 hlist_move_list(&obj_to_free, &tofree);
 324                 debug_objects_freed += obj_nr_tofree;
 325                 WRITE_ONCE(obj_nr_tofree, 0);
 326         }
 327         raw_spin_unlock_irqrestore(&pool_lock, flags);
 328
 329         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 330                 hlist_del(&obj->node);
 331                 kmem_cache_free(obj_cache, obj);
 332         }
 333 }
 334
 335 static void __free_object(struct debug_obj *obj)
 336 {
 337         struct debug_obj *objs[ODEBUG_BATCH_SIZE];
 338         struct debug_percpu_free *percpu_pool;
 339         int lookahead_count = 0;
 340         unsigned long flags;
 341         bool work;
 342
 343         local_irq_save(flags);
 344         if (!obj_cache)
 345                 goto free_to_obj_pool;
 346
 347         /*
 348          * Try to free it into the percpu pool first.
 349          */
 350         percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 351         if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
 352                 hlist_add_head(&obj->node, &percpu_pool->free_objs);
 353                 percpu_pool->obj_free++;
 354                 local_irq_restore(flags);
 355                 return;
 356         }
 357
 358         /*
 359          * As the percpu pool is full, look ahead and pull out a batch
 360          * of objects from the percpu pool and free them as well.
 361          */
 362         for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
 363                 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
 364                 if (!objs[lookahead_count])
 365                         break;
 366                 percpu_pool->obj_free--;
 367         }
 368
 369 free_to_obj_pool:
 370         raw_spin_lock(&pool_lock);
 371         work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
 372                (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
 373         obj_pool_used--;
 374
 375         if (work) {
 376                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 377                 hlist_add_head(&obj->node, &obj_to_free);
 378                 if (lookahead_count) {
 379                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
 380                         obj_pool_used -= lookahead_count;
 381                         while (lookahead_count) {
 382                                 hlist_add_head(&objs[--lookahead_count]->node,
 383                                                &obj_to_free);
 384                         }
 385                 }
 386
 387                 if ((obj_pool_free > debug_objects_pool_size) &&
 388                     (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
 389                         int i;
 390
 391                         /*
 392                          * Free one more batch of objects from obj_pool.
 393                          */
 394                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 395                                 obj = __alloc_object(&obj_pool);
 396                                 hlist_add_head(&obj->node, &obj_to_free);
 397                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 398                                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 399                         }
 400                 }
 401         } else {
 402                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 403                 hlist_add_head(&obj->node, &obj_pool);
 404                 if (lookahead_count) {
 405                         WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
 406                         obj_pool_used -= lookahead_count;
 407                         while (lookahead_count) {
 408                                 hlist_add_head(&objs[--lookahead_count]->node,
 409                                                &obj_pool);
 410                         }
 411                 }
 412         }
 413         raw_spin_unlock(&pool_lock);
 414         local_irq_restore(flags);
 415 }
 416
 417 /*
 418  * Put the object back into the pool and schedule work to free objects
 419  * if necessary.
 420  */
 421 static void free_object(struct debug_obj *obj)
 422 {
 423         __free_object(obj);
 424         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
 425                 WRITE_ONCE(obj_freeing, true);
 426                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
 427         }
 428 }
 429
 430 #ifdef CONFIG_HOTPLUG_CPU
 431 static int object_cpu_offline(unsigned int cpu)
 432 {
 433         struct debug_percpu_free *percpu_pool;
 434         struct hlist_node *tmp;
 435         struct debug_obj *obj;
 436         unsigned long flags;
 437
 438         /* Remote access is safe as the CPU is dead already */
 439         percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
 440         hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
 441                 hlist_del(&obj->node);
 442                 kmem_cache_free(obj_cache, obj);
 443         }
 444
 445         raw_spin_lock_irqsave(&pool_lock, flags);
 446         obj_pool_used -= percpu_pool->obj_free;
 447         debug_objects_freed += percpu_pool->obj_free;
 448         raw_spin_unlock_irqrestore(&pool_lock, flags);
 449
 450         percpu_pool->obj_free = 0;
 451
 452         return 0;
 453 }
 454 #endif
 455
 456 /*
 457  * We run out of memory. That means we probably have tons of objects
 458  * allocated.
 459  */
 460 static void debug_objects_oom(void)
 461 {
 462         struct debug_bucket *db = obj_hash;
 463         struct hlist_node *tmp;
 464         HLIST_HEAD(freelist);
 465         struct debug_obj *obj;
 466         unsigned long flags;
 467         int i;
 468
 469         pr_warn("Out of memory. ODEBUG disabled\n");
 470
 471         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 472                 raw_spin_lock_irqsave(&db->lock, flags);
 473                 hlist_move_list(&db->list, &freelist);
 474                 raw_spin_unlock_irqrestore(&db->lock, flags);
 475
 476                 /* Now free them */
 477                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 478                         hlist_del(&obj->node);
 479                         free_object(obj);
 480                 }
 481         }
 482 }
 483
 484 /*
 485  * We use the pfn of the address for the hash. That way we can check
 486  * for freed objects simply by checking the affected bucket.
 487  */
 488 static struct debug_bucket *get_bucket(unsigned long addr)
 489 {
 490         unsigned long hash;
 491
 492         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 493         return &obj_hash[hash];
 494 }
 495
 496 static void debug_print_object(struct debug_obj *obj, char *msg)
 497 {
 498         const struct debug_obj_descr *descr = obj->descr;
 499         static int limit;
 500
 501         if (limit < 5 && descr != descr_test) {
 502                 void *hint = descr->debug_hint ?
 503                         descr->debug_hint(obj->object) : NULL;
 504                 limit++;
 505                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 506                                  "object: %p object type: %s hint: %pS\n",
 507                         msg, obj_states[obj->state], obj->astate,
 508                         obj->object, descr->name, hint);
 509         }
 510         debug_objects_warnings++;
 511 }
 512
 513 /*
 514  * Try to repair the damage, so we have a better chance to get useful
 515  * debug output.
 516  */
 517 static bool
 518 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 519                    void * addr, enum debug_obj_state state)
 520 {
 521         if (fixup && fixup(addr, state)) {
 522                 debug_objects_fixups++;
 523                 return true;
 524         }
 525         return false;
 526 }
 527
 528 static void debug_object_is_on_stack(void *addr, int onstack)
 529 {
 530         int is_on_stack;
 531         static int limit;
 532
 533         if (limit > 4)
 534                 return;
 535
 536         is_on_stack = object_is_on_stack(addr);
 537         if (is_on_stack == onstack)
 538                 return;
 539
 540         limit++;
 541         if (is_on_stack)
 542                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 543                          task_stack_page(current));
 544         else
 545                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 546                          task_stack_page(current));
 547
 548         WARN_ON(1);
 549 }
 550
 551 static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
 552                                                 const struct debug_obj_descr *descr,
 553                                                 bool onstack, bool alloc_ifstatic)
 554 {
 555         struct debug_obj *obj = lookup_object(addr, b);
 556         enum debug_obj_state state = ODEBUG_STATE_NONE;
 557
 558         if (likely(obj))
 559                 return obj;
 560
 561         /*
 562          * debug_object_init() unconditionally allocates untracked
 563          * objects. It does not matter whether it is a static object or
 564          * not.
 565          *
 566          * debug_object_assert_init() and debug_object_activate() allow
 567          * allocation only if the descriptor callback confirms that the
 568          * object is static and considered initialized. For non-static
 569          * objects the allocation needs to be done from the fixup callback.
 570          */
 571         if (unlikely(alloc_ifstatic)) {
 572                 if (!descr->is_static_object || !descr->is_static_object(addr))
 573                         return ERR_PTR(-ENOENT);
 574                 /* Statically allocated objects are considered initialized */
 575                 state = ODEBUG_STATE_INIT;
 576         }
 577
 578         obj = alloc_object(addr, b, descr);
 579         if (likely(obj)) {
 580                 obj->state = state;
 581                 debug_object_is_on_stack(addr, onstack);
 582                 return obj;
 583         }
 584
 585         /* Out of memory. Do the cleanup outside of the locked region */
 586         debug_objects_enabled = 0;
 587         return NULL;
 588 }
 589
 590 static void debug_objects_fill_pool(void)
 591 {
 592         /*
 593          * On RT enabled kernels the pool refill must happen in preemptible
 594          * context:
 595          */
 596         if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
 597                 fill_pool();
 598 }
 599
 600 static void
 601 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
 602 {
 603         enum debug_obj_state state;
 604         struct debug_bucket *db;
 605         struct debug_obj *obj;
 606         unsigned long flags;
 607
 608         debug_objects_fill_pool();
 609
 610         db = get_bucket((unsigned long) addr);
 611
 612         raw_spin_lock_irqsave(&db->lock, flags);
 613
 614         obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
 615         if (unlikely(!obj)) {
 616                 raw_spin_unlock_irqrestore(&db->lock, flags);
 617                 debug_objects_oom();
 618                 return;
 619         }
 620
 621         switch (obj->state) {
 622         case ODEBUG_STATE_NONE:
 623         case ODEBUG_STATE_INIT:
 624         case ODEBUG_STATE_INACTIVE:
 625                 obj->state = ODEBUG_STATE_INIT;
 626                 break;
 627
 628         case ODEBUG_STATE_ACTIVE:
 629                 state = obj->state;
 630                 raw_spin_unlock_irqrestore(&db->lock, flags);
 631                 debug_print_object(obj, "init");
 632                 debug_object_fixup(descr->fixup_init, addr, state);
 633                 return;
 634
 635         case ODEBUG_STATE_DESTROYED:
 636                 raw_spin_unlock_irqrestore(&db->lock, flags);
 637                 debug_print_object(obj, "init");
 638                 return;
 639         default:
 640                 break;
 641         }
 642
 643         raw_spin_unlock_irqrestore(&db->lock, flags);
 644 }
 645
 646 /**
 647  * debug_object_init - debug checks when an object is initialized
 648  * @addr:       address of the object
 649  * @descr:      pointer to an object specific debug description structure
 650  */
 651 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
 652 {
 653         if (!debug_objects_enabled)
 654                 return;
 655
 656         __debug_object_init(addr, descr, 0);
 657 }
 658 EXPORT_SYMBOL_GPL(debug_object_init);
 659
 660 /**
 661  * debug_object_init_on_stack - debug checks when an object on stack is
 662  *                              initialized
 663  * @addr:       address of the object
 664  * @descr:      pointer to an object specific debug description structure
 665  */
 666 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
 667 {
 668         if (!debug_objects_enabled)
 669                 return;
 670
 671         __debug_object_init(addr, descr, 1);
 672 }
 673 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 674
 675 /**
 676  * debug_object_activate - debug checks when an object is activated
 677  * @addr:       address of the object
 678  * @descr:      pointer to an object specific debug description structure
 679  * Returns 0 for success, -EINVAL for check failed.
 680  */
 681 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
 682 {
 683         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 684         enum debug_obj_state state;
 685         struct debug_bucket *db;
 686         struct debug_obj *obj;
 687         unsigned long flags;
 688         int ret;
 689
 690         if (!debug_objects_enabled)
 691                 return 0;
 692
 693         debug_objects_fill_pool();
 694
 695         db = get_bucket((unsigned long) addr);
 696
 697         raw_spin_lock_irqsave(&db->lock, flags);
 698
 699         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 700         if (likely(!IS_ERR_OR_NULL(obj))) {
 701                 bool print_object = false;
 702
 703                 switch (obj->state) {
 704                 case ODEBUG_STATE_INIT:
 705                 case ODEBUG_STATE_INACTIVE:
 706                         obj->state = ODEBUG_STATE_ACTIVE;
 707                         ret = 0;
 708                         break;
 709
 710                 case ODEBUG_STATE_ACTIVE:
 711                         state = obj->state;
 712                         raw_spin_unlock_irqrestore(&db->lock, flags);
 713                         debug_print_object(obj, "activate");
 714                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 715                         return ret ? 0 : -EINVAL;
 716
 717                 case ODEBUG_STATE_DESTROYED:
 718                         print_object = true;
 719                         ret = -EINVAL;
 720                         break;
 721                 default:
 722                         ret = 0;
 723                         break;
 724                 }
 725                 raw_spin_unlock_irqrestore(&db->lock, flags);
 726                 if (print_object)
 727                         debug_print_object(obj, "activate");
 728                 return ret;
 729         }
 730
 731         raw_spin_unlock_irqrestore(&db->lock, flags);
 732
 733         /* If NULL the allocation has hit OOM */
 734         if (!obj) {
 735                 debug_objects_oom();
 736                 return 0;
 737         }
 738
 739         /* Object is neither static nor tracked. It's not initialized */
 740         debug_print_object(&o, "activate");
 741         ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE);
 742         return ret ? 0 : -EINVAL;
 743 }
 744 EXPORT_SYMBOL_GPL(debug_object_activate);
 745
 746 /**
 747  * debug_object_deactivate - debug checks when an object is deactivated
 748  * @addr:       address of the object
 749  * @descr:      pointer to an object specific debug description structure
 750  */
 751 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
 752 {
 753         struct debug_bucket *db;
 754         struct debug_obj *obj;
 755         unsigned long flags;
 756         bool print_object = false;
 757
 758         if (!debug_objects_enabled)
 759                 return;
 760
 761         db = get_bucket((unsigned long) addr);
 762
 763         raw_spin_lock_irqsave(&db->lock, flags);
 764
 765         obj = lookup_object(addr, db);
 766         if (obj) {
 767                 switch (obj->state) {
 768                 case ODEBUG_STATE_INIT:
 769                 case ODEBUG_STATE_INACTIVE:
 770                 case ODEBUG_STATE_ACTIVE:
 771                         if (!obj->astate)
 772                                 obj->state = ODEBUG_STATE_INACTIVE;
 773                         else
 774                                 print_object = true;
 775                         break;
 776
 777                 case ODEBUG_STATE_DESTROYED:
 778                         print_object = true;
 779                         break;
 780                 default:
 781                         break;
 782                 }
 783         }
 784
 785         raw_spin_unlock_irqrestore(&db->lock, flags);
 786         if (!obj) {
 787                 struct debug_obj o = { .object = addr,
 788                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 789                                        .descr = descr };
 790
 791                 debug_print_object(&o, "deactivate");
 792         } else if (print_object) {
 793                 debug_print_object(obj, "deactivate");
 794         }
 795 }
 796 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 797
 798 /**
 799  * debug_object_destroy - debug checks when an object is destroyed
 800  * @addr:       address of the object
 801  * @descr:      pointer to an object specific debug description structure
 802  */
 803 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
 804 {
 805         enum debug_obj_state state;
 806         struct debug_bucket *db;
 807         struct debug_obj *obj;
 808         unsigned long flags;
 809         bool print_object = false;
 810
 811         if (!debug_objects_enabled)
 812                 return;
 813
 814         db = get_bucket((unsigned long) addr);
 815
 816         raw_spin_lock_irqsave(&db->lock, flags);
 817
 818         obj = lookup_object(addr, db);
 819         if (!obj)
 820                 goto out_unlock;
 821
 822         switch (obj->state) {
 823         case ODEBUG_STATE_NONE:
 824         case ODEBUG_STATE_INIT:
 825         case ODEBUG_STATE_INACTIVE:
 826                 obj->state = ODEBUG_STATE_DESTROYED;
 827                 break;
 828         case ODEBUG_STATE_ACTIVE:
 829                 state = obj->state;
 830                 raw_spin_unlock_irqrestore(&db->lock, flags);
 831                 debug_print_object(obj, "destroy");
 832                 debug_object_fixup(descr->fixup_destroy, addr, state);
 833                 return;
 834
 835         case ODEBUG_STATE_DESTROYED:
 836                 print_object = true;
 837                 break;
 838         default:
 839                 break;
 840         }
 841 out_unlock:
 842         raw_spin_unlock_irqrestore(&db->lock, flags);
 843         if (print_object)
 844                 debug_print_object(obj, "destroy");
 845 }
 846 EXPORT_SYMBOL_GPL(debug_object_destroy);
 847
 848 /**
 849  * debug_object_free - debug checks when an object is freed
 850  * @addr:       address of the object
 851  * @descr:      pointer to an object specific debug description structure
 852  */
 853 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
 854 {
 855         enum debug_obj_state state;
 856         struct debug_bucket *db;
 857         struct debug_obj *obj;
 858         unsigned long flags;
 859
 860         if (!debug_objects_enabled)
 861                 return;
 862
 863         db = get_bucket((unsigned long) addr);
 864
 865         raw_spin_lock_irqsave(&db->lock, flags);
 866
 867         obj = lookup_object(addr, db);
 868         if (!obj)
 869                 goto out_unlock;
 870
 871         switch (obj->state) {
 872         case ODEBUG_STATE_ACTIVE:
 873                 state = obj->state;
 874                 raw_spin_unlock_irqrestore(&db->lock, flags);
 875                 debug_print_object(obj, "free");
 876                 debug_object_fixup(descr->fixup_free, addr, state);
 877                 return;
 878         default:
 879                 hlist_del(&obj->node);
 880                 raw_spin_unlock_irqrestore(&db->lock, flags);
 881                 free_object(obj);
 882                 return;
 883         }
 884 out_unlock:
 885         raw_spin_unlock_irqrestore(&db->lock, flags);
 886 }
 887 EXPORT_SYMBOL_GPL(debug_object_free);
 888
 889 /**
 890  * debug_object_assert_init - debug checks when object should be init-ed
 891  * @addr:       address of the object
 892  * @descr:      pointer to an object specific debug description structure
 893  */
 894 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
 895 {
 896         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 897         struct debug_bucket *db;
 898         struct debug_obj *obj;
 899         unsigned long flags;
 900
 901         if (!debug_objects_enabled)
 902                 return;
 903
 904         debug_objects_fill_pool();
 905
 906         db = get_bucket((unsigned long) addr);
 907
 908         raw_spin_lock_irqsave(&db->lock, flags);
 909         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 910         raw_spin_unlock_irqrestore(&db->lock, flags);
 911         if (likely(!IS_ERR_OR_NULL(obj)))
 912                 return;
 913
 914         /* If NULL the allocation has hit OOM */
 915         if (!obj) {
 916                 debug_objects_oom();
 917                 return;
 918         }
 919
 920         /* Object is neither tracked nor static. It's not initialized. */
 921         debug_print_object(&o, "assert_init");
 922         debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
 923 }
 924 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 925
 926 /**
 927  * debug_object_active_state - debug checks object usage state machine
 928  * @addr:       address of the object
 929  * @descr:      pointer to an object specific debug description structure
 930  * @expect:     expected state
 931  * @next:       state to move to if expected state is found
 932  */
 933 void
 934 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
 935                           unsigned int expect, unsigned int next)
 936 {
 937         struct debug_bucket *db;
 938         struct debug_obj *obj;
 939         unsigned long flags;
 940         bool print_object = false;
 941
 942         if (!debug_objects_enabled)
 943                 return;
 944
 945         db = get_bucket((unsigned long) addr);
 946
 947         raw_spin_lock_irqsave(&db->lock, flags);
 948
 949         obj = lookup_object(addr, db);
 950         if (obj) {
 951                 switch (obj->state) {
 952                 case ODEBUG_STATE_ACTIVE:
 953                         if (obj->astate == expect)
 954                                 obj->astate = next;
 955                         else
 956                                 print_object = true;
 957                         break;
 958
 959                 default:
 960                         print_object = true;
 961                         break;
 962                 }
 963         }
 964
 965         raw_spin_unlock_irqrestore(&db->lock, flags);
 966         if (!obj) {
 967                 struct debug_obj o = { .object = addr,
 968                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 969                                        .descr = descr };
 970
 971                 debug_print_object(&o, "active_state");
 972         } else if (print_object) {
 973                 debug_print_object(obj, "active_state");
 974         }
 975 }
 976 EXPORT_SYMBOL_GPL(debug_object_active_state);
 977
 978 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 979 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 980 {
 981         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 982         const struct debug_obj_descr *descr;
 983         enum debug_obj_state state;
 984         struct debug_bucket *db;
 985         struct hlist_node *tmp;
 986         struct debug_obj *obj;
 987         int cnt, objs_checked = 0;
 988
 989         saddr = (unsigned long) address;
 990         eaddr = saddr + size;
 991         paddr = saddr & ODEBUG_CHUNK_MASK;
 992         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 993         chunks >>= ODEBUG_CHUNK_SHIFT;
 994
 995         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 996                 db = get_bucket(paddr);
 997
 998 repeat:
 999                 cnt = 0;
1000                 raw_spin_lock_irqsave(&db->lock, flags);
1001                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
1002                         cnt++;
1003                         oaddr = (unsigned long) obj->object;
1004                         if (oaddr < saddr || oaddr >= eaddr)
1005                                 continue;
1006
1007                         switch (obj->state) {
1008                         case ODEBUG_STATE_ACTIVE:
1009                                 descr = obj->descr;
1010                                 state = obj->state;
1011                                 raw_spin_unlock_irqrestore(&db->lock, flags);
1012                                 debug_print_object(obj, "free");
1013                                 debug_object_fixup(descr->fixup_free,
1014                                                    (void *) oaddr, state);
1015                                 goto repeat;
1016                         default:
1017                                 hlist_del(&obj->node);
1018                                 __free_object(obj);
1019                                 break;
1020                         }
1021                 }
1022                 raw_spin_unlock_irqrestore(&db->lock, flags);
1023
1024                 if (cnt > debug_objects_maxchain)
1025                         debug_objects_maxchain = cnt;
1026
1027                 objs_checked += cnt;
1028         }
1029
1030         if (objs_checked > debug_objects_maxchecked)
1031                 debug_objects_maxchecked = objs_checked;
1032
1033         /* Schedule work to actually kmem_cache_free() objects */
1034         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1035                 WRITE_ONCE(obj_freeing, true);
1036                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1037         }
1038 }
1039
1040 void debug_check_no_obj_freed(const void *address, unsigned long size)
1041 {
1042         if (debug_objects_enabled)
1043                 __debug_check_no_obj_freed(address, size);
1044 }
1045 #endif
1046
1047 #ifdef CONFIG_DEBUG_FS
1048
1049 static int debug_stats_show(struct seq_file *m, void *v)
1050 {
1051         int cpu, obj_percpu_free = 0;
1052
1053         for_each_possible_cpu(cpu)
1054                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1055
1056         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1057         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1058         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1059         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1060         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1061         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1062         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1063         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1064         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1065         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1066         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1067         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1068         return 0;
1069 }
1070 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1071
1072 static int __init debug_objects_init_debugfs(void)
1073 {
1074         struct dentry *dbgdir;
1075
1076         if (!debug_objects_enabled)
1077                 return 0;
1078
1079         dbgdir = debugfs_create_dir("debug_objects", NULL);
1080
1081         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1082
1083         return 0;
1084 }
1085 __initcall(debug_objects_init_debugfs);
1086
1087 #else
1088 static inline void debug_objects_init_debugfs(void) { }
1089 #endif
1090
1091 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1092
1093 /* Random data structure for the self test */
1094 struct self_test {
1095         unsigned long   dummy1[6];
1096         int             static_init;
1097         unsigned long   dummy2[3];
1098 };
1099
1100 static __initconst const struct debug_obj_descr descr_type_test;
1101
1102 static bool __init is_static_object(void *addr)
1103 {
1104         struct self_test *obj = addr;
1105
1106         return obj->static_init;
1107 }
1108
1109 /*
1110  * fixup_init is called when:
1111  * - an active object is initialized
1112  */
1113 static bool __init fixup_init(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_init(obj, &descr_type_test);
1121                 return true;
1122         default:
1123                 return false;
1124         }
1125 }
1126
1127 /*
1128  * fixup_activate is called when:
1129  * - an active object is activated
1130  * - an unknown non-static object is activated
1131  */
1132 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1133 {
1134         struct self_test *obj = addr;
1135
1136         switch (state) {
1137         case ODEBUG_STATE_NOTAVAILABLE:
1138                 return true;
1139         case ODEBUG_STATE_ACTIVE:
1140                 debug_object_deactivate(obj, &descr_type_test);
1141                 debug_object_activate(obj, &descr_type_test);
1142                 return true;
1143
1144         default:
1145                 return false;
1146         }
1147 }
1148
1149 /*
1150  * fixup_destroy is called when:
1151  * - an active object is destroyed
1152  */
1153 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1154 {
1155         struct self_test *obj = addr;
1156
1157         switch (state) {
1158         case ODEBUG_STATE_ACTIVE:
1159                 debug_object_deactivate(obj, &descr_type_test);
1160                 debug_object_destroy(obj, &descr_type_test);
1161                 return true;
1162         default:
1163                 return false;
1164         }
1165 }
1166
1167 /*
1168  * fixup_free is called when:
1169  * - an active object is freed
1170  */
1171 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1172 {
1173         struct self_test *obj = addr;
1174
1175         switch (state) {
1176         case ODEBUG_STATE_ACTIVE:
1177                 debug_object_deactivate(obj, &descr_type_test);
1178                 debug_object_free(obj, &descr_type_test);
1179                 return true;
1180         default:
1181                 return false;
1182         }
1183 }
1184
1185 static int __init
1186 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1187 {
1188         struct debug_bucket *db;
1189         struct debug_obj *obj;
1190         unsigned long flags;
1191         int res = -EINVAL;
1192
1193         db = get_bucket((unsigned long) addr);
1194
1195         raw_spin_lock_irqsave(&db->lock, flags);
1196
1197         obj = lookup_object(addr, db);
1198         if (!obj && state != ODEBUG_STATE_NONE) {
1199                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1200                 goto out;
1201         }
1202         if (obj && obj->state != state) {
1203                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1204                        obj->state, state);
1205                 goto out;
1206         }
1207         if (fixups != debug_objects_fixups) {
1208                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1209                        fixups, debug_objects_fixups);
1210                 goto out;
1211         }
1212         if (warnings != debug_objects_warnings) {
1213                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1214                        warnings, debug_objects_warnings);
1215                 goto out;
1216         }
1217         res = 0;
1218 out:
1219         raw_spin_unlock_irqrestore(&db->lock, flags);
1220         if (res)
1221                 debug_objects_enabled = 0;
1222         return res;
1223 }
1224
1225 static __initconst const struct debug_obj_descr descr_type_test = {
1226         .name                   = "selftest",
1227         .is_static_object       = is_static_object,
1228         .fixup_init             = fixup_init,
1229         .fixup_activate         = fixup_activate,
1230         .fixup_destroy          = fixup_destroy,
1231         .fixup_free             = fixup_free,
1232 };
1233
1234 static __initdata struct self_test obj = { .static_init = 0 };
1235
1236 static void __init debug_objects_selftest(void)
1237 {
1238         int fixups, oldfixups, warnings, oldwarnings;
1239         unsigned long flags;
1240
1241         local_irq_save(flags);
1242
1243         fixups = oldfixups = debug_objects_fixups;
1244         warnings = oldwarnings = debug_objects_warnings;
1245         descr_test = &descr_type_test;
1246
1247         debug_object_init(&obj, &descr_type_test);
1248         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1249                 goto out;
1250         debug_object_activate(&obj, &descr_type_test);
1251         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1252                 goto out;
1253         debug_object_activate(&obj, &descr_type_test);
1254         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1255                 goto out;
1256         debug_object_deactivate(&obj, &descr_type_test);
1257         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1258                 goto out;
1259         debug_object_destroy(&obj, &descr_type_test);
1260         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1261                 goto out;
1262         debug_object_init(&obj, &descr_type_test);
1263         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1264                 goto out;
1265         debug_object_activate(&obj, &descr_type_test);
1266         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1267                 goto out;
1268         debug_object_deactivate(&obj, &descr_type_test);
1269         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1270                 goto out;
1271         debug_object_free(&obj, &descr_type_test);
1272         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1273                 goto out;
1274
1275         obj.static_init = 1;
1276         debug_object_activate(&obj, &descr_type_test);
1277         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1278                 goto out;
1279         debug_object_init(&obj, &descr_type_test);
1280         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1281                 goto out;
1282         debug_object_free(&obj, &descr_type_test);
1283         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1284                 goto out;
1285
1286 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1287         debug_object_init(&obj, &descr_type_test);
1288         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1289                 goto out;
1290         debug_object_activate(&obj, &descr_type_test);
1291         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1292                 goto out;
1293         __debug_check_no_obj_freed(&obj, sizeof(obj));
1294         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1295                 goto out;
1296 #endif
1297         pr_info("selftest passed\n");
1298
1299 out:
1300         debug_objects_fixups = oldfixups;
1301         debug_objects_warnings = oldwarnings;
1302         descr_test = NULL;
1303
1304         local_irq_restore(flags);
1305 }
1306 #else
1307 static inline void debug_objects_selftest(void) { }
1308 #endif
1309
1310 /*
1311  * Called during early boot to initialize the hash buckets and link
1312  * the static object pool objects into the poll list. After this call
1313  * the object tracker is fully operational.
1314  */
1315 void __init debug_objects_early_init(void)
1316 {
1317         int i;
1318
1319         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1320                 raw_spin_lock_init(&obj_hash[i].lock);
1321
1322         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1323                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1324 }
1325
1326 /*
1327  * Convert the statically allocated objects to dynamic ones:
1328  */
1329 static int __init debug_objects_replace_static_objects(void)
1330 {
1331         struct debug_bucket *db = obj_hash;
1332         struct hlist_node *tmp;
1333         struct debug_obj *obj, *new;
1334         HLIST_HEAD(objects);
1335         int i, cnt = 0;
1336
1337         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1338                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1339                 if (!obj)
1340                         goto free;
1341                 hlist_add_head(&obj->node, &objects);
1342         }
1343
1344         debug_objects_allocated += i;
1345
1346         /*
1347          * debug_objects_mem_init() is now called early that only one CPU is up
1348          * and interrupts have been disabled, so it is safe to replace the
1349          * active object references.
1350          */
1351
1352         /* Remove the statically allocated objects from the pool */
1353         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1354                 hlist_del(&obj->node);
1355         /* Move the allocated objects to the pool */
1356         hlist_move_list(&objects, &obj_pool);
1357
1358         /* Replace the active object references */
1359         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1360                 hlist_move_list(&db->list, &objects);
1361
1362                 hlist_for_each_entry(obj, &objects, node) {
1363                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1364                         hlist_del(&new->node);
1365                         /* copy object data */
1366                         *new = *obj;
1367                         hlist_add_head(&new->node, &db->list);
1368                         cnt++;
1369                 }
1370         }
1371
1372         pr_debug("%d of %d active objects replaced\n",
1373                  cnt, obj_pool_used);
1374         return 0;
1375 free:
1376         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1377                 hlist_del(&obj->node);
1378                 kmem_cache_free(obj_cache, obj);
1379         }
1380         return -ENOMEM;
1381 }
1382
1383 /*
1384  * Called after the kmem_caches are functional to setup a dedicated
1385  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1386  * prevents that the debug code is called on kmem_cache_free() for the
1387  * debug tracker objects to avoid recursive calls.
1388  */
1389 void __init debug_objects_mem_init(void)
1390 {
1391         int cpu, extras;
1392
1393         if (!debug_objects_enabled)
1394                 return;
1395
1396         /*
1397          * Initialize the percpu object pools
1398          *
1399          * Initialization is not strictly necessary, but was done for
1400          * completeness.
1401          */
1402         for_each_possible_cpu(cpu)
1403                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1404
1405         obj_cache = kmem_cache_create("debug_objects_cache",
1406                                       sizeof (struct debug_obj), 0,
1407                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1408                                       NULL);
1409
1410         if (!obj_cache || debug_objects_replace_static_objects()) {
1411                 debug_objects_enabled = 0;
1412                 kmem_cache_destroy(obj_cache);
1413                 pr_warn("out of memory.\n");
1414                 return;
1415         } else
1416                 debug_objects_selftest();
1417
1418 #ifdef CONFIG_HOTPLUG_CPU
1419         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1420                                         object_cpu_offline);
1421 #endif
1422
1423         /*
1424          * Increase the thresholds for allocating and freeing objects
1425          * according to the number of possible CPUs available in the system.
1426          */
1427         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1428         debug_objects_pool_size += extras;
1429         debug_objects_pool_min_level += extras;
1430 }