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 <[email protected]>
   6  */
   7
   8 #define pr_fmt(fmt) "ODEBUG: " fmt
   9
  10 #include <linux/cpu.h>
  11 #include <linux/debugobjects.h>
  12 #include <linux/debugfs.h>
  13 #include <linux/hash.h>
  14 #include <linux/kmemleak.h>
  15 #include <linux/sched.h>
  16 #include <linux/sched/loadavg.h>
  17 #include <linux/sched/task_stack.h>
  18 #include <linux/seq_file.h>
  19 #include <linux/slab.h>
  20 #include <linux/static_key.h>
  21
  22 #define ODEBUG_HASH_BITS        14
  23 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  24
  25 /* Must be power of two */
  26 #define ODEBUG_BATCH_SIZE       16
  27
  28 /* Initial values. Must all be a multiple of batch size */
  29 #define ODEBUG_POOL_SIZE        (64 * ODEBUG_BATCH_SIZE)
  30 #define ODEBUG_POOL_MIN_LEVEL   (ODEBUG_POOL_SIZE / 4)
  31
  32 #define ODEBUG_POOL_PERCPU_SIZE (8 * ODEBUG_BATCH_SIZE)
  33
  34 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  35 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  36 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  37
  38 /*
  39  * We limit the freeing of debug objects via workqueue at a maximum
  40  * frequency of 10Hz and about 1024 objects for each freeing operation.
  41  * So it is freeing at most 10k debug objects per second.
  42  */
  43 #define ODEBUG_FREE_WORK_MAX    (1024 / ODEBUG_BATCH_SIZE)
  44 #define ODEBUG_FREE_WORK_DELAY  DIV_ROUND_UP(HZ, 10)
  45
  46 struct debug_bucket {
  47         struct hlist_head       list;
  48         raw_spinlock_t          lock;
  49 };
  50
  51 struct pool_stats {
  52         unsigned int            cur_used;
  53         unsigned int            max_used;
  54         unsigned int            min_fill;
  55 };
  56
  57 struct obj_pool {
  58         struct hlist_head       objects;
  59         unsigned int            cnt;
  60         unsigned int            min_cnt;
  61         unsigned int            max_cnt;
  62         struct pool_stats       stats;
  63 } ____cacheline_aligned;
  64
  65
  66 static DEFINE_PER_CPU_ALIGNED(struct obj_pool, pool_pcpu)  = {
  67         .max_cnt        = ODEBUG_POOL_PERCPU_SIZE,
  68 };
  69
  70 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  71
  72 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  73
  74 static DEFINE_RAW_SPINLOCK(pool_lock);
  75
  76 static struct obj_pool pool_global = {
  77         .min_cnt                = ODEBUG_POOL_MIN_LEVEL,
  78         .max_cnt                = ODEBUG_POOL_SIZE,
  79         .stats                  = {
  80                 .min_fill       = ODEBUG_POOL_SIZE,
  81         },
  82 };
  83
  84 static struct obj_pool pool_to_free = {
  85         .max_cnt        = UINT_MAX,
  86 };
  87
  88 static HLIST_HEAD(pool_boot);
  89
  90 static unsigned long            avg_usage;
  91 static bool                     obj_freeing;
  92
  93 static int __data_racy                  debug_objects_maxchain __read_mostly;
  94 static int __data_racy __maybe_unused   debug_objects_maxchecked __read_mostly;
  95 static int __data_racy                  debug_objects_fixups __read_mostly;
  96 static int __data_racy                  debug_objects_warnings __read_mostly;
  97 static bool __data_racy                 debug_objects_enabled __read_mostly
  98                                         = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  99
 100 static const struct debug_obj_descr     *descr_test  __read_mostly;
 101 static struct kmem_cache                *obj_cache __ro_after_init;
 102
 103 /*
 104  * Track numbers of kmem_cache_alloc()/free() calls done.
 105  */
 106 static int __data_racy          debug_objects_allocated;
 107 static int __data_racy          debug_objects_freed;
 108
 109 static void free_obj_work(struct work_struct *work);
 110 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
 111
 112 static DEFINE_STATIC_KEY_FALSE(obj_cache_enabled);
 113
 114 static int __init enable_object_debug(char *str)
 115 {
 116         debug_objects_enabled = true;
 117         return 0;
 118 }
 119 early_param("debug_objects", enable_object_debug);
 120
 121 static int __init disable_object_debug(char *str)
 122 {
 123         debug_objects_enabled = false;
 124         return 0;
 125 }
 126 early_param("no_debug_objects", disable_object_debug);
 127
 128 static const char *obj_states[ODEBUG_STATE_MAX] = {
 129         [ODEBUG_STATE_NONE]             = "none",
 130         [ODEBUG_STATE_INIT]             = "initialized",
 131         [ODEBUG_STATE_INACTIVE]         = "inactive",
 132         [ODEBUG_STATE_ACTIVE]           = "active",
 133         [ODEBUG_STATE_DESTROYED]        = "destroyed",
 134         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
 135 };
 136
 137 static __always_inline unsigned int pool_count(struct obj_pool *pool)
 138 {
 139         return READ_ONCE(pool->cnt);
 140 }
 141
 142 static __always_inline bool pool_should_refill(struct obj_pool *pool)
 143 {
 144         return pool_count(pool) < pool->min_cnt;
 145 }
 146
 147 static __always_inline bool pool_must_refill(struct obj_pool *pool)
 148 {
 149         return pool_count(pool) < pool->min_cnt / 2;
 150 }
 151
 152 static bool pool_move_batch(struct obj_pool *dst, struct obj_pool *src)
 153 {
 154         struct hlist_node *last, *next_batch, *first_batch;
 155         struct debug_obj *obj;
 156
 157         if (dst->cnt >= dst->max_cnt || !src->cnt)
 158                 return false;
 159
 160         first_batch = src->objects.first;
 161         obj = hlist_entry(first_batch, typeof(*obj), node);
 162         last = obj->batch_last;
 163         next_batch = last->next;
 164
 165         /* Move the next batch to the front of the source pool */
 166         src->objects.first = next_batch;
 167         if (next_batch)
 168                 next_batch->pprev = &src->objects.first;
 169
 170         /* Add the extracted batch to the destination pool */
 171         last->next = dst->objects.first;
 172         if (last->next)
 173                 last->next->pprev = &last->next;
 174         first_batch->pprev = &dst->objects.first;
 175         dst->objects.first = first_batch;
 176
 177         WRITE_ONCE(src->cnt, src->cnt - ODEBUG_BATCH_SIZE);
 178         WRITE_ONCE(dst->cnt, dst->cnt + ODEBUG_BATCH_SIZE);
 179         return true;
 180 }
 181
 182 static bool pool_push_batch(struct obj_pool *dst, struct hlist_head *head)
 183 {
 184         struct hlist_node *last;
 185         struct debug_obj *obj;
 186
 187         if (dst->cnt >= dst->max_cnt)
 188                 return false;
 189
 190         obj = hlist_entry(head->first, typeof(*obj), node);
 191         last = obj->batch_last;
 192
 193         hlist_splice_init(head, last, &dst->objects);
 194         WRITE_ONCE(dst->cnt, dst->cnt + ODEBUG_BATCH_SIZE);
 195         return true;
 196 }
 197
 198 static bool pool_pop_batch(struct hlist_head *head, struct obj_pool *src)
 199 {
 200         struct hlist_node *last, *next;
 201         struct debug_obj *obj;
 202
 203         if (!src->cnt)
 204                 return false;
 205
 206         /* Move the complete list to the head */
 207         hlist_move_list(&src->objects, head);
 208
 209         obj = hlist_entry(head->first, typeof(*obj), node);
 210         last = obj->batch_last;
 211         next = last->next;
 212         /* Disconnect the batch from the list */
 213         last->next = NULL;
 214
 215         /* Move the node after last back to the source pool. */
 216         src->objects.first = next;
 217         if (next)
 218                 next->pprev = &src->objects.first;
 219
 220         WRITE_ONCE(src->cnt, src->cnt - ODEBUG_BATCH_SIZE);
 221         return true;
 222 }
 223
 224 static struct debug_obj *__alloc_object(struct hlist_head *list)
 225 {
 226         struct debug_obj *obj;
 227
 228         if (unlikely(!list->first))
 229                 return NULL;
 230
 231         obj = hlist_entry(list->first, typeof(*obj), node);
 232         hlist_del(&obj->node);
 233         return obj;
 234 }
 235
 236 static void pcpu_refill_stats(void)
 237 {
 238         struct pool_stats *stats = &pool_global.stats;
 239
 240         WRITE_ONCE(stats->cur_used, stats->cur_used + ODEBUG_BATCH_SIZE);
 241
 242         if (stats->cur_used > stats->max_used)
 243                 stats->max_used = stats->cur_used;
 244
 245         if (pool_global.cnt < stats->min_fill)
 246                 stats->min_fill = pool_global.cnt;
 247 }
 248
 249 static struct debug_obj *pcpu_alloc(void)
 250 {
 251         struct obj_pool *pcp = this_cpu_ptr(&pool_pcpu);
 252
 253         lockdep_assert_irqs_disabled();
 254
 255         for (;;) {
 256                 struct debug_obj *obj = __alloc_object(&pcp->objects);
 257
 258                 if (likely(obj)) {
 259                         pcp->cnt--;
 260                         /*
 261                          * If this emptied a batch try to refill from the
 262                          * free pool. Don't do that if this was the top-most
 263                          * batch as pcpu_free() expects the per CPU pool
 264                          * to be less than ODEBUG_POOL_PERCPU_SIZE.
 265                          */
 266                         if (unlikely(pcp->cnt < (ODEBUG_POOL_PERCPU_SIZE - ODEBUG_BATCH_SIZE) &&
 267                                      !(pcp->cnt % ODEBUG_BATCH_SIZE))) {
 268                                 /*
 269                                  * Don't try to allocate from the regular pool here
 270                                  * to not exhaust it prematurely.
 271                                  */
 272                                 if (pool_count(&pool_to_free)) {
 273                                         guard(raw_spinlock)(&pool_lock);
 274                                         pool_move_batch(pcp, &pool_to_free);
 275                                         pcpu_refill_stats();
 276                                 }
 277                         }
 278                         return obj;
 279                 }
 280
 281                 guard(raw_spinlock)(&pool_lock);
 282                 if (!pool_move_batch(pcp, &pool_to_free)) {
 283                         if (!pool_move_batch(pcp, &pool_global))
 284                                 return NULL;
 285                 }
 286                 pcpu_refill_stats();
 287         }
 288 }
 289
 290 static void pcpu_free(struct debug_obj *obj)
 291 {
 292         struct obj_pool *pcp = this_cpu_ptr(&pool_pcpu);
 293         struct debug_obj *first;
 294
 295         lockdep_assert_irqs_disabled();
 296
 297         if (!(pcp->cnt % ODEBUG_BATCH_SIZE)) {
 298                 obj->batch_last = &obj->node;
 299         } else {
 300                 first = hlist_entry(pcp->objects.first, typeof(*first), node);
 301                 obj->batch_last = first->batch_last;
 302         }
 303         hlist_add_head(&obj->node, &pcp->objects);
 304         pcp->cnt++;
 305
 306         /* Pool full ? */
 307         if (pcp->cnt < ODEBUG_POOL_PERCPU_SIZE)
 308                 return;
 309
 310         /* Remove a batch from the per CPU pool */
 311         guard(raw_spinlock)(&pool_lock);
 312         /* Try to fit the batch into the pool_global first */
 313         if (!pool_move_batch(&pool_global, pcp))
 314                 pool_move_batch(&pool_to_free, pcp);
 315         WRITE_ONCE(pool_global.stats.cur_used, pool_global.stats.cur_used - ODEBUG_BATCH_SIZE);
 316 }
 317
 318 static void free_object_list(struct hlist_head *head)
 319 {
 320         struct hlist_node *tmp;
 321         struct debug_obj *obj;
 322         int cnt = 0;
 323
 324         hlist_for_each_entry_safe(obj, tmp, head, node) {
 325                 hlist_del(&obj->node);
 326                 kmem_cache_free(obj_cache, obj);
 327                 cnt++;
 328         }
 329         debug_objects_freed += cnt;
 330 }
 331
 332 static void fill_pool_from_freelist(void)
 333 {
 334         static unsigned long state;
 335
 336         /*
 337          * Reuse objs from the global obj_to_free list; they will be
 338          * reinitialized when allocating.
 339          */
 340         if (!pool_count(&pool_to_free))
 341                 return;
 342
 343         /*
 344          * Prevent the context from being scheduled or interrupted after
 345          * setting the state flag;
 346          */
 347         guard(irqsave)();
 348
 349         /*
 350          * Avoid lock contention on &pool_lock and avoid making the cache
 351          * line exclusive by testing the bit before attempting to set it.
 352          */
 353         if (test_bit(0, &state) || test_and_set_bit(0, &state))
 354                 return;
 355
 356         /* Avoid taking the lock when there is no work to do */
 357         while (pool_should_refill(&pool_global) && pool_count(&pool_to_free)) {
 358                 guard(raw_spinlock)(&pool_lock);
 359                 /* Move a batch if possible */
 360                 pool_move_batch(&pool_global, &pool_to_free);
 361         }
 362         clear_bit(0, &state);
 363 }
 364
 365 static bool kmem_alloc_batch(struct hlist_head *head, struct kmem_cache *cache, gfp_t gfp)
 366 {
 367         struct hlist_node *last = NULL;
 368         struct debug_obj *obj;
 369
 370         for (int cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
 371                 obj = kmem_cache_zalloc(cache, gfp);
 372                 if (!obj) {
 373                         free_object_list(head);
 374                         return false;
 375                 }
 376                 debug_objects_allocated++;
 377
 378                 if (!last)
 379                         last = &obj->node;
 380                 obj->batch_last = last;
 381
 382                 hlist_add_head(&obj->node, head);
 383         }
 384         return true;
 385 }
 386
 387 static void fill_pool(void)
 388 {
 389         static atomic_t cpus_allocating;
 390
 391         /*
 392          * Avoid allocation and lock contention when:
 393          *   - One other CPU is already allocating
 394          *   - the global pool has not reached the critical level yet
 395          */
 396         if (!pool_must_refill(&pool_global) && atomic_read(&cpus_allocating))
 397                 return;
 398
 399         atomic_inc(&cpus_allocating);
 400         while (pool_should_refill(&pool_global)) {
 401                 HLIST_HEAD(head);
 402
 403                 if (!kmem_alloc_batch(&head, obj_cache, __GFP_HIGH | __GFP_NOWARN))
 404                         break;
 405
 406                 guard(raw_spinlock_irqsave)(&pool_lock);
 407                 if (!pool_push_batch(&pool_global, &head))
 408                         pool_push_batch(&pool_to_free, &head);
 409         }
 410         atomic_dec(&cpus_allocating);
 411 }
 412
 413 /*
 414  * Lookup an object in the hash bucket.
 415  */
 416 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 417 {
 418         struct debug_obj *obj;
 419         int cnt = 0;
 420
 421         hlist_for_each_entry(obj, &b->list, node) {
 422                 cnt++;
 423                 if (obj->object == addr)
 424                         return obj;
 425         }
 426         if (cnt > debug_objects_maxchain)
 427                 debug_objects_maxchain = cnt;
 428
 429         return NULL;
 430 }
 431
 432 static void calc_usage(void)
 433 {
 434         static DEFINE_RAW_SPINLOCK(avg_lock);
 435         static unsigned long avg_period;
 436         unsigned long cur, now = jiffies;
 437
 438         if (!time_after_eq(now, READ_ONCE(avg_period)))
 439                 return;
 440
 441         if (!raw_spin_trylock(&avg_lock))
 442                 return;
 443
 444         WRITE_ONCE(avg_period, now + msecs_to_jiffies(10));
 445         cur = READ_ONCE(pool_global.stats.cur_used) * ODEBUG_FREE_WORK_MAX;
 446         WRITE_ONCE(avg_usage, calc_load(avg_usage, EXP_5, cur));
 447         raw_spin_unlock(&avg_lock);
 448 }
 449
 450 static struct debug_obj *alloc_object(void *addr, struct debug_bucket *b,
 451                                       const struct debug_obj_descr *descr)
 452 {
 453         struct debug_obj *obj;
 454
 455         calc_usage();
 456
 457         if (static_branch_likely(&obj_cache_enabled))
 458                 obj = pcpu_alloc();
 459         else
 460                 obj = __alloc_object(&pool_boot);
 461
 462         if (likely(obj)) {
 463                 obj->object = addr;
 464                 obj->descr  = descr;
 465                 obj->state  = ODEBUG_STATE_NONE;
 466                 obj->astate = 0;
 467                 hlist_add_head(&obj->node, &b->list);
 468         }
 469         return obj;
 470 }
 471
 472 /* workqueue function to free objects. */
 473 static void free_obj_work(struct work_struct *work)
 474 {
 475         static unsigned long last_use_avg;
 476         unsigned long cur_used, last_used, delta;
 477         unsigned int max_free = 0;
 478
 479         WRITE_ONCE(obj_freeing, false);
 480
 481         /* Rate limit freeing based on current use average */
 482         cur_used = READ_ONCE(avg_usage);
 483         last_used = last_use_avg;
 484         last_use_avg = cur_used;
 485
 486         if (!pool_count(&pool_to_free))
 487                 return;
 488
 489         if (cur_used <= last_used) {
 490                 delta = (last_used - cur_used) / ODEBUG_FREE_WORK_MAX;
 491                 max_free = min(delta, ODEBUG_FREE_WORK_MAX);
 492         }
 493
 494         for (int cnt = 0; cnt < ODEBUG_FREE_WORK_MAX; cnt++) {
 495                 HLIST_HEAD(tofree);
 496
 497                 /* Acquire and drop the lock for each batch */
 498                 scoped_guard(raw_spinlock_irqsave, &pool_lock) {
 499                         if (!pool_to_free.cnt)
 500                                 return;
 501
 502                         /* Refill the global pool if possible */
 503                         if (pool_move_batch(&pool_global, &pool_to_free)) {
 504                                 /* Don't free as there seems to be demand */
 505                                 max_free = 0;
 506                         } else if (max_free) {
 507                                 pool_pop_batch(&tofree, &pool_to_free);
 508                                 max_free--;
 509                         } else {
 510                                 return;
 511                         }
 512                 }
 513                 free_object_list(&tofree);
 514         }
 515 }
 516
 517 static void __free_object(struct debug_obj *obj)
 518 {
 519         guard(irqsave)();
 520         if (static_branch_likely(&obj_cache_enabled))
 521                 pcpu_free(obj);
 522         else
 523                 hlist_add_head(&obj->node, &pool_boot);
 524 }
 525
 526 /*
 527  * Put the object back into the pool and schedule work to free objects
 528  * if necessary.
 529  */
 530 static void free_object(struct debug_obj *obj)
 531 {
 532         __free_object(obj);
 533         if (!READ_ONCE(obj_freeing) && pool_count(&pool_to_free)) {
 534                 WRITE_ONCE(obj_freeing, true);
 535                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
 536         }
 537 }
 538
 539 static void put_objects(struct hlist_head *list)
 540 {
 541         struct hlist_node *tmp;
 542         struct debug_obj *obj;
 543
 544         /*
 545          * Using free_object() puts the objects into reuse or schedules
 546          * them for freeing and it get's all the accounting correct.
 547          */
 548         hlist_for_each_entry_safe(obj, tmp, list, node) {
 549                 hlist_del(&obj->node);
 550                 free_object(obj);
 551         }
 552 }
 553
 554 #ifdef CONFIG_HOTPLUG_CPU
 555 static int object_cpu_offline(unsigned int cpu)
 556 {
 557         /* Remote access is safe as the CPU is dead already */
 558         struct obj_pool *pcp = per_cpu_ptr(&pool_pcpu, cpu);
 559
 560         put_objects(&pcp->objects);
 561         pcp->cnt = 0;
 562         return 0;
 563 }
 564 #endif
 565
 566 /* Out of memory. Free all objects from hash */
 567 static void debug_objects_oom(void)
 568 {
 569         struct debug_bucket *db = obj_hash;
 570         HLIST_HEAD(freelist);
 571
 572         pr_warn("Out of memory. ODEBUG disabled\n");
 573
 574         for (int i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 575                 scoped_guard(raw_spinlock_irqsave, &db->lock)
 576                         hlist_move_list(&db->list, &freelist);
 577
 578                 put_objects(&freelist);
 579         }
 580 }
 581
 582 /*
 583  * We use the pfn of the address for the hash. That way we can check
 584  * for freed objects simply by checking the affected bucket.
 585  */
 586 static struct debug_bucket *get_bucket(unsigned long addr)
 587 {
 588         unsigned long hash;
 589
 590         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 591         return &obj_hash[hash];
 592 }
 593
 594 static void debug_print_object(struct debug_obj *obj, char *msg)
 595 {
 596         const struct debug_obj_descr *descr = obj->descr;
 597         static int limit;
 598
 599         /*
 600          * Don't report if lookup_object_or_alloc() by the current thread
 601          * failed because lookup_object_or_alloc()/debug_objects_oom() by a
 602          * concurrent thread turned off debug_objects_enabled and cleared
 603          * the hash buckets.
 604          */
 605         if (!debug_objects_enabled)
 606                 return;
 607
 608         if (limit < 5 && descr != descr_test) {
 609                 void *hint = descr->debug_hint ?
 610                         descr->debug_hint(obj->object) : NULL;
 611                 limit++;
 612                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 613                                  "object: %p object type: %s hint: %pS\n",
 614                         msg, obj_states[obj->state], obj->astate,
 615                         obj->object, descr->name, hint);
 616         }
 617         debug_objects_warnings++;
 618 }
 619
 620 /*
 621  * Try to repair the damage, so we have a better chance to get useful
 622  * debug output.
 623  */
 624 static bool
 625 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 626                    void * addr, enum debug_obj_state state)
 627 {
 628         if (fixup && fixup(addr, state)) {
 629                 debug_objects_fixups++;
 630                 return true;
 631         }
 632         return false;
 633 }
 634
 635 static void debug_object_is_on_stack(void *addr, int onstack)
 636 {
 637         int is_on_stack;
 638         static int limit;
 639
 640         if (limit > 4)
 641                 return;
 642
 643         is_on_stack = object_is_on_stack(addr);
 644         if (is_on_stack == onstack)
 645                 return;
 646
 647         limit++;
 648         if (is_on_stack)
 649                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 650                          task_stack_page(current));
 651         else
 652                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 653                          task_stack_page(current));
 654
 655         WARN_ON(1);
 656 }
 657
 658 static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
 659                                                 const struct debug_obj_descr *descr,
 660                                                 bool onstack, bool alloc_ifstatic)
 661 {
 662         struct debug_obj *obj = lookup_object(addr, b);
 663         enum debug_obj_state state = ODEBUG_STATE_NONE;
 664
 665         if (likely(obj))
 666                 return obj;
 667
 668         /*
 669          * debug_object_init() unconditionally allocates untracked
 670          * objects. It does not matter whether it is a static object or
 671          * not.
 672          *
 673          * debug_object_assert_init() and debug_object_activate() allow
 674          * allocation only if the descriptor callback confirms that the
 675          * object is static and considered initialized. For non-static
 676          * objects the allocation needs to be done from the fixup callback.
 677          */
 678         if (unlikely(alloc_ifstatic)) {
 679                 if (!descr->is_static_object || !descr->is_static_object(addr))
 680                         return ERR_PTR(-ENOENT);
 681                 /* Statically allocated objects are considered initialized */
 682                 state = ODEBUG_STATE_INIT;
 683         }
 684
 685         obj = alloc_object(addr, b, descr);
 686         if (likely(obj)) {
 687                 obj->state = state;
 688                 debug_object_is_on_stack(addr, onstack);
 689                 return obj;
 690         }
 691
 692         /* Out of memory. Do the cleanup outside of the locked region */
 693         debug_objects_enabled = false;
 694         return NULL;
 695 }
 696
 697 static void debug_objects_fill_pool(void)
 698 {
 699         if (!static_branch_likely(&obj_cache_enabled))
 700                 return;
 701
 702         if (likely(!pool_should_refill(&pool_global)))
 703                 return;
 704
 705         /* Try reusing objects from obj_to_free_list */
 706         fill_pool_from_freelist();
 707
 708         if (likely(!pool_should_refill(&pool_global)))
 709                 return;
 710
 711         /*
 712          * On RT enabled kernels the pool refill must happen in preemptible
 713          * context -- for !RT kernels we rely on the fact that spinlock_t and
 714          * raw_spinlock_t are basically the same type and this lock-type
 715          * inversion works just fine.
 716          */
 717         if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible()) {
 718                 /*
 719                  * Annotate away the spinlock_t inside raw_spinlock_t warning
 720                  * by temporarily raising the wait-type to WAIT_SLEEP, matching
 721                  * the preemptible() condition above.
 722                  */
 723                 static DEFINE_WAIT_OVERRIDE_MAP(fill_pool_map, LD_WAIT_SLEEP);
 724                 lock_map_acquire_try(&fill_pool_map);
 725                 fill_pool();
 726                 lock_map_release(&fill_pool_map);
 727         }
 728 }
 729
 730 static void
 731 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
 732 {
 733         struct debug_obj *obj, o;
 734         struct debug_bucket *db;
 735         unsigned long flags;
 736
 737         debug_objects_fill_pool();
 738
 739         db = get_bucket((unsigned long) addr);
 740
 741         raw_spin_lock_irqsave(&db->lock, flags);
 742
 743         obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
 744         if (unlikely(!obj)) {
 745                 raw_spin_unlock_irqrestore(&db->lock, flags);
 746                 debug_objects_oom();
 747                 return;
 748         }
 749
 750         switch (obj->state) {
 751         case ODEBUG_STATE_NONE:
 752         case ODEBUG_STATE_INIT:
 753         case ODEBUG_STATE_INACTIVE:
 754                 obj->state = ODEBUG_STATE_INIT;
 755                 raw_spin_unlock_irqrestore(&db->lock, flags);
 756                 return;
 757         default:
 758                 break;
 759         }
 760
 761         o = *obj;
 762         raw_spin_unlock_irqrestore(&db->lock, flags);
 763         debug_print_object(&o, "init");
 764
 765         if (o.state == ODEBUG_STATE_ACTIVE)
 766                 debug_object_fixup(descr->fixup_init, addr, o.state);
 767 }
 768
 769 /**
 770  * debug_object_init - debug checks when an object is initialized
 771  * @addr:       address of the object
 772  * @descr:      pointer to an object specific debug description structure
 773  */
 774 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
 775 {
 776         if (!debug_objects_enabled)
 777                 return;
 778
 779         __debug_object_init(addr, descr, 0);
 780 }
 781 EXPORT_SYMBOL_GPL(debug_object_init);
 782
 783 /**
 784  * debug_object_init_on_stack - debug checks when an object on stack is
 785  *                              initialized
 786  * @addr:       address of the object
 787  * @descr:      pointer to an object specific debug description structure
 788  */
 789 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
 790 {
 791         if (!debug_objects_enabled)
 792                 return;
 793
 794         __debug_object_init(addr, descr, 1);
 795 }
 796 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 797
 798 /**
 799  * debug_object_activate - debug checks when an object is activated
 800  * @addr:       address of the object
 801  * @descr:      pointer to an object specific debug description structure
 802  * Returns 0 for success, -EINVAL for check failed.
 803  */
 804 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
 805 {
 806         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 807         struct debug_bucket *db;
 808         struct debug_obj *obj;
 809         unsigned long flags;
 810
 811         if (!debug_objects_enabled)
 812                 return 0;
 813
 814         debug_objects_fill_pool();
 815
 816         db = get_bucket((unsigned long) addr);
 817
 818         raw_spin_lock_irqsave(&db->lock, flags);
 819
 820         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 821         if (unlikely(!obj)) {
 822                 raw_spin_unlock_irqrestore(&db->lock, flags);
 823                 debug_objects_oom();
 824                 return 0;
 825         } else if (likely(!IS_ERR(obj))) {
 826                 switch (obj->state) {
 827                 case ODEBUG_STATE_ACTIVE:
 828                 case ODEBUG_STATE_DESTROYED:
 829                         o = *obj;
 830                         break;
 831                 case ODEBUG_STATE_INIT:
 832                 case ODEBUG_STATE_INACTIVE:
 833                         obj->state = ODEBUG_STATE_ACTIVE;
 834                         fallthrough;
 835                 default:
 836                         raw_spin_unlock_irqrestore(&db->lock, flags);
 837                         return 0;
 838                 }
 839         }
 840
 841         raw_spin_unlock_irqrestore(&db->lock, flags);
 842         debug_print_object(&o, "activate");
 843
 844         switch (o.state) {
 845         case ODEBUG_STATE_ACTIVE:
 846         case ODEBUG_STATE_NOTAVAILABLE:
 847                 if (debug_object_fixup(descr->fixup_activate, addr, o.state))
 848                         return 0;
 849                 fallthrough;
 850         default:
 851                 return -EINVAL;
 852         }
 853 }
 854 EXPORT_SYMBOL_GPL(debug_object_activate);
 855
 856 /**
 857  * debug_object_deactivate - debug checks when an object is deactivated
 858  * @addr:       address of the object
 859  * @descr:      pointer to an object specific debug description structure
 860  */
 861 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
 862 {
 863         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 864         struct debug_bucket *db;
 865         struct debug_obj *obj;
 866         unsigned long flags;
 867
 868         if (!debug_objects_enabled)
 869                 return;
 870
 871         db = get_bucket((unsigned long) addr);
 872
 873         raw_spin_lock_irqsave(&db->lock, flags);
 874
 875         obj = lookup_object(addr, db);
 876         if (obj) {
 877                 switch (obj->state) {
 878                 case ODEBUG_STATE_DESTROYED:
 879                         break;
 880                 case ODEBUG_STATE_INIT:
 881                 case ODEBUG_STATE_INACTIVE:
 882                 case ODEBUG_STATE_ACTIVE:
 883                         if (obj->astate)
 884                                 break;
 885                         obj->state = ODEBUG_STATE_INACTIVE;
 886                         fallthrough;
 887                 default:
 888                         raw_spin_unlock_irqrestore(&db->lock, flags);
 889                         return;
 890                 }
 891                 o = *obj;
 892         }
 893
 894         raw_spin_unlock_irqrestore(&db->lock, flags);
 895         debug_print_object(&o, "deactivate");
 896 }
 897 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 898
 899 /**
 900  * debug_object_destroy - debug checks when an object is destroyed
 901  * @addr:       address of the object
 902  * @descr:      pointer to an object specific debug description structure
 903  */
 904 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
 905 {
 906         struct debug_obj *obj, o;
 907         struct debug_bucket *db;
 908         unsigned long flags;
 909
 910         if (!debug_objects_enabled)
 911                 return;
 912
 913         db = get_bucket((unsigned long) addr);
 914
 915         raw_spin_lock_irqsave(&db->lock, flags);
 916
 917         obj = lookup_object(addr, db);
 918         if (!obj) {
 919                 raw_spin_unlock_irqrestore(&db->lock, flags);
 920                 return;
 921         }
 922
 923         switch (obj->state) {
 924         case ODEBUG_STATE_ACTIVE:
 925         case ODEBUG_STATE_DESTROYED:
 926                 break;
 927         case ODEBUG_STATE_NONE:
 928         case ODEBUG_STATE_INIT:
 929         case ODEBUG_STATE_INACTIVE:
 930                 obj->state = ODEBUG_STATE_DESTROYED;
 931                 fallthrough;
 932         default:
 933                 raw_spin_unlock_irqrestore(&db->lock, flags);
 934                 return;
 935         }
 936
 937         o = *obj;
 938         raw_spin_unlock_irqrestore(&db->lock, flags);
 939         debug_print_object(&o, "destroy");
 940
 941         if (o.state == ODEBUG_STATE_ACTIVE)
 942                 debug_object_fixup(descr->fixup_destroy, addr, o.state);
 943 }
 944 EXPORT_SYMBOL_GPL(debug_object_destroy);
 945
 946 /**
 947  * debug_object_free - debug checks when an object is freed
 948  * @addr:       address of the object
 949  * @descr:      pointer to an object specific debug description structure
 950  */
 951 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
 952 {
 953         struct debug_obj *obj, o;
 954         struct debug_bucket *db;
 955         unsigned long flags;
 956
 957         if (!debug_objects_enabled)
 958                 return;
 959
 960         db = get_bucket((unsigned long) addr);
 961
 962         raw_spin_lock_irqsave(&db->lock, flags);
 963
 964         obj = lookup_object(addr, db);
 965         if (!obj) {
 966                 raw_spin_unlock_irqrestore(&db->lock, flags);
 967                 return;
 968         }
 969
 970         switch (obj->state) {
 971         case ODEBUG_STATE_ACTIVE:
 972                 break;
 973         default:
 974                 hlist_del(&obj->node);
 975                 raw_spin_unlock_irqrestore(&db->lock, flags);
 976                 free_object(obj);
 977                 return;
 978         }
 979
 980         o = *obj;
 981         raw_spin_unlock_irqrestore(&db->lock, flags);
 982         debug_print_object(&o, "free");
 983
 984         debug_object_fixup(descr->fixup_free, addr, o.state);
 985 }
 986 EXPORT_SYMBOL_GPL(debug_object_free);
 987
 988 /**
 989  * debug_object_assert_init - debug checks when object should be init-ed
 990  * @addr:       address of the object
 991  * @descr:      pointer to an object specific debug description structure
 992  */
 993 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
 994 {
 995         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 996         struct debug_bucket *db;
 997         struct debug_obj *obj;
 998         unsigned long flags;
 999
1000         if (!debug_objects_enabled)
1001                 return;
1002
1003         debug_objects_fill_pool();
1004
1005         db = get_bucket((unsigned long) addr);
1006
1007         raw_spin_lock_irqsave(&db->lock, flags);
1008         obj = lookup_object_or_alloc(addr, db, descr, false, true);
1009         raw_spin_unlock_irqrestore(&db->lock, flags);
1010         if (likely(!IS_ERR_OR_NULL(obj)))
1011                 return;
1012
1013         /* If NULL the allocation has hit OOM */
1014         if (!obj) {
1015                 debug_objects_oom();
1016                 return;
1017         }
1018
1019         /* Object is neither tracked nor static. It's not initialized. */
1020         debug_print_object(&o, "assert_init");
1021         debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
1022 }
1023 EXPORT_SYMBOL_GPL(debug_object_assert_init);
1024
1025 /**
1026  * debug_object_active_state - debug checks object usage state machine
1027  * @addr:       address of the object
1028  * @descr:      pointer to an object specific debug description structure
1029  * @expect:     expected state
1030  * @next:       state to move to if expected state is found
1031  */
1032 void
1033 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
1034                           unsigned int expect, unsigned int next)
1035 {
1036         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
1037         struct debug_bucket *db;
1038         struct debug_obj *obj;
1039         unsigned long flags;
1040
1041         if (!debug_objects_enabled)
1042                 return;
1043
1044         db = get_bucket((unsigned long) addr);
1045
1046         raw_spin_lock_irqsave(&db->lock, flags);
1047
1048         obj = lookup_object(addr, db);
1049         if (obj) {
1050                 switch (obj->state) {
1051                 case ODEBUG_STATE_ACTIVE:
1052                         if (obj->astate != expect)
1053                                 break;
1054                         obj->astate = next;
1055                         raw_spin_unlock_irqrestore(&db->lock, flags);
1056                         return;
1057                 default:
1058                         break;
1059                 }
1060                 o = *obj;
1061         }
1062
1063         raw_spin_unlock_irqrestore(&db->lock, flags);
1064         debug_print_object(&o, "active_state");
1065 }
1066 EXPORT_SYMBOL_GPL(debug_object_active_state);
1067
1068 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1069 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
1070 {
1071         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
1072         int cnt, objs_checked = 0;
1073         struct debug_obj *obj, o;
1074         struct debug_bucket *db;
1075         struct hlist_node *tmp;
1076
1077         saddr = (unsigned long) address;
1078         eaddr = saddr + size;
1079         paddr = saddr & ODEBUG_CHUNK_MASK;
1080         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
1081         chunks >>= ODEBUG_CHUNK_SHIFT;
1082
1083         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
1084                 db = get_bucket(paddr);
1085
1086 repeat:
1087                 cnt = 0;
1088                 raw_spin_lock_irqsave(&db->lock, flags);
1089                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
1090                         cnt++;
1091                         oaddr = (unsigned long) obj->object;
1092                         if (oaddr < saddr || oaddr >= eaddr)
1093                                 continue;
1094
1095                         switch (obj->state) {
1096                         case ODEBUG_STATE_ACTIVE:
1097                                 o = *obj;
1098                                 raw_spin_unlock_irqrestore(&db->lock, flags);
1099                                 debug_print_object(&o, "free");
1100                                 debug_object_fixup(o.descr->fixup_free, (void *)oaddr, o.state);
1101                                 goto repeat;
1102                         default:
1103                                 hlist_del(&obj->node);
1104                                 __free_object(obj);
1105                                 break;
1106                         }
1107                 }
1108                 raw_spin_unlock_irqrestore(&db->lock, flags);
1109
1110                 if (cnt > debug_objects_maxchain)
1111                         debug_objects_maxchain = cnt;
1112
1113                 objs_checked += cnt;
1114         }
1115
1116         if (objs_checked > debug_objects_maxchecked)
1117                 debug_objects_maxchecked = objs_checked;
1118
1119         /* Schedule work to actually kmem_cache_free() objects */
1120         if (!READ_ONCE(obj_freeing) && pool_count(&pool_to_free)) {
1121                 WRITE_ONCE(obj_freeing, true);
1122                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1123         }
1124 }
1125
1126 void debug_check_no_obj_freed(const void *address, unsigned long size)
1127 {
1128         if (debug_objects_enabled)
1129                 __debug_check_no_obj_freed(address, size);
1130 }
1131 #endif
1132
1133 #ifdef CONFIG_DEBUG_FS
1134
1135 static int debug_stats_show(struct seq_file *m, void *v)
1136 {
1137         unsigned int cpu, pool_used, pcp_free = 0;
1138
1139         /*
1140          * pool_global.stats.cur_used is the number of batches currently
1141          * handed out to per CPU pools. Convert it to number of objects
1142          * and subtract the number of free objects in the per CPU pools.
1143          * As this is lockless the number is an estimate.
1144          */
1145         for_each_possible_cpu(cpu)
1146                 pcp_free += per_cpu(pool_pcpu.cnt, cpu);
1147
1148         pool_used = READ_ONCE(pool_global.stats.cur_used);
1149         pcp_free = min(pool_used, pcp_free);
1150         pool_used -= pcp_free;
1151
1152         seq_printf(m, "max_chain     : %d\n", debug_objects_maxchain);
1153         seq_printf(m, "max_checked   : %d\n", debug_objects_maxchecked);
1154         seq_printf(m, "warnings      : %d\n", debug_objects_warnings);
1155         seq_printf(m, "fixups        : %d\n", debug_objects_fixups);
1156         seq_printf(m, "pool_free     : %u\n", pool_count(&pool_global) + pcp_free);
1157         seq_printf(m, "pool_pcp_free : %u\n", pcp_free);
1158         seq_printf(m, "pool_min_free : %u\n", data_race(pool_global.stats.min_fill));
1159         seq_printf(m, "pool_used     : %u\n", pool_used);
1160         seq_printf(m, "pool_max_used : %u\n", data_race(pool_global.stats.max_used));
1161         seq_printf(m, "on_free_list  : %u\n", pool_count(&pool_to_free));
1162         seq_printf(m, "objs_allocated: %d\n", debug_objects_allocated);
1163         seq_printf(m, "objs_freed    : %d\n", debug_objects_freed);
1164         return 0;
1165 }
1166 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1167
1168 static int __init debug_objects_init_debugfs(void)
1169 {
1170         struct dentry *dbgdir;
1171
1172         if (!debug_objects_enabled)
1173                 return 0;
1174
1175         dbgdir = debugfs_create_dir("debug_objects", NULL);
1176
1177         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1178
1179         return 0;
1180 }
1181 __initcall(debug_objects_init_debugfs);
1182
1183 #else
1184 static inline void debug_objects_init_debugfs(void) { }
1185 #endif
1186
1187 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1188
1189 /* Random data structure for the self test */
1190 struct self_test {
1191         unsigned long   dummy1[6];
1192         int             static_init;
1193         unsigned long   dummy2[3];
1194 };
1195
1196 static __initconst const struct debug_obj_descr descr_type_test;
1197
1198 static bool __init is_static_object(void *addr)
1199 {
1200         struct self_test *obj = addr;
1201
1202         return obj->static_init;
1203 }
1204
1205 /*
1206  * fixup_init is called when:
1207  * - an active object is initialized
1208  */
1209 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1210 {
1211         struct self_test *obj = addr;
1212
1213         switch (state) {
1214         case ODEBUG_STATE_ACTIVE:
1215                 debug_object_deactivate(obj, &descr_type_test);
1216                 debug_object_init(obj, &descr_type_test);
1217                 return true;
1218         default:
1219                 return false;
1220         }
1221 }
1222
1223 /*
1224  * fixup_activate is called when:
1225  * - an active object is activated
1226  * - an unknown non-static object is activated
1227  */
1228 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1229 {
1230         struct self_test *obj = addr;
1231
1232         switch (state) {
1233         case ODEBUG_STATE_NOTAVAILABLE:
1234                 return true;
1235         case ODEBUG_STATE_ACTIVE:
1236                 debug_object_deactivate(obj, &descr_type_test);
1237                 debug_object_activate(obj, &descr_type_test);
1238                 return true;
1239
1240         default:
1241                 return false;
1242         }
1243 }
1244
1245 /*
1246  * fixup_destroy is called when:
1247  * - an active object is destroyed
1248  */
1249 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1250 {
1251         struct self_test *obj = addr;
1252
1253         switch (state) {
1254         case ODEBUG_STATE_ACTIVE:
1255                 debug_object_deactivate(obj, &descr_type_test);
1256                 debug_object_destroy(obj, &descr_type_test);
1257                 return true;
1258         default:
1259                 return false;
1260         }
1261 }
1262
1263 /*
1264  * fixup_free is called when:
1265  * - an active object is freed
1266  */
1267 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1268 {
1269         struct self_test *obj = addr;
1270
1271         switch (state) {
1272         case ODEBUG_STATE_ACTIVE:
1273                 debug_object_deactivate(obj, &descr_type_test);
1274                 debug_object_free(obj, &descr_type_test);
1275                 return true;
1276         default:
1277                 return false;
1278         }
1279 }
1280
1281 static int __init
1282 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1283 {
1284         struct debug_bucket *db;
1285         struct debug_obj *obj;
1286         unsigned long flags;
1287         int res = -EINVAL;
1288
1289         db = get_bucket((unsigned long) addr);
1290
1291         raw_spin_lock_irqsave(&db->lock, flags);
1292
1293         obj = lookup_object(addr, db);
1294         if (!obj && state != ODEBUG_STATE_NONE) {
1295                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1296                 goto out;
1297         }
1298         if (obj && obj->state != state) {
1299                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1300                        obj->state, state);
1301                 goto out;
1302         }
1303         if (fixups != debug_objects_fixups) {
1304                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1305                        fixups, debug_objects_fixups);
1306                 goto out;
1307         }
1308         if (warnings != debug_objects_warnings) {
1309                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1310                        warnings, debug_objects_warnings);
1311                 goto out;
1312         }
1313         res = 0;
1314 out:
1315         raw_spin_unlock_irqrestore(&db->lock, flags);
1316         if (res)
1317                 debug_objects_enabled = false;
1318         return res;
1319 }
1320
1321 static __initconst const struct debug_obj_descr descr_type_test = {
1322         .name                   = "selftest",
1323         .is_static_object       = is_static_object,
1324         .fixup_init             = fixup_init,
1325         .fixup_activate         = fixup_activate,
1326         .fixup_destroy          = fixup_destroy,
1327         .fixup_free             = fixup_free,
1328 };
1329
1330 static __initdata struct self_test obj = { .static_init = 0 };
1331
1332 static bool __init debug_objects_selftest(void)
1333 {
1334         int fixups, oldfixups, warnings, oldwarnings;
1335         unsigned long flags;
1336
1337         local_irq_save(flags);
1338
1339         fixups = oldfixups = debug_objects_fixups;
1340         warnings = oldwarnings = debug_objects_warnings;
1341         descr_test = &descr_type_test;
1342
1343         debug_object_init(&obj, &descr_type_test);
1344         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1345                 goto out;
1346         debug_object_activate(&obj, &descr_type_test);
1347         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1348                 goto out;
1349         debug_object_activate(&obj, &descr_type_test);
1350         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1351                 goto out;
1352         debug_object_deactivate(&obj, &descr_type_test);
1353         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1354                 goto out;
1355         debug_object_destroy(&obj, &descr_type_test);
1356         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1357                 goto out;
1358         debug_object_init(&obj, &descr_type_test);
1359         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1360                 goto out;
1361         debug_object_activate(&obj, &descr_type_test);
1362         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1363                 goto out;
1364         debug_object_deactivate(&obj, &descr_type_test);
1365         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1366                 goto out;
1367         debug_object_free(&obj, &descr_type_test);
1368         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1369                 goto out;
1370
1371         obj.static_init = 1;
1372         debug_object_activate(&obj, &descr_type_test);
1373         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1374                 goto out;
1375         debug_object_init(&obj, &descr_type_test);
1376         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1377                 goto out;
1378         debug_object_free(&obj, &descr_type_test);
1379         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1380                 goto out;
1381
1382 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1383         debug_object_init(&obj, &descr_type_test);
1384         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1385                 goto out;
1386         debug_object_activate(&obj, &descr_type_test);
1387         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1388                 goto out;
1389         __debug_check_no_obj_freed(&obj, sizeof(obj));
1390         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1391                 goto out;
1392 #endif
1393         pr_info("selftest passed\n");
1394
1395 out:
1396         debug_objects_fixups = oldfixups;
1397         debug_objects_warnings = oldwarnings;
1398         descr_test = NULL;
1399
1400         local_irq_restore(flags);
1401         return debug_objects_enabled;
1402 }
1403 #else
1404 static inline bool debug_objects_selftest(void) { return true; }
1405 #endif
1406
1407 /*
1408  * Called during early boot to initialize the hash buckets and link
1409  * the static object pool objects into the poll list. After this call
1410  * the object tracker is fully operational.
1411  */
1412 void __init debug_objects_early_init(void)
1413 {
1414         int i;
1415
1416         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1417                 raw_spin_lock_init(&obj_hash[i].lock);
1418
1419         /* Keep early boot simple and add everything to the boot list */
1420         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1421                 hlist_add_head(&obj_static_pool[i].node, &pool_boot);
1422 }
1423
1424 /*
1425  * Convert the statically allocated objects to dynamic ones.
1426  * debug_objects_mem_init() is called early so only one CPU is up and
1427  * interrupts are disabled, which means it is safe to replace the active
1428  * object references.
1429  */
1430 static bool __init debug_objects_replace_static_objects(struct kmem_cache *cache)
1431 {
1432         struct debug_bucket *db = obj_hash;
1433         struct hlist_node *tmp;
1434         struct debug_obj *obj;
1435         HLIST_HEAD(objects);
1436         int i;
1437
1438         for (i = 0; i < ODEBUG_POOL_SIZE; i += ODEBUG_BATCH_SIZE) {
1439                 if (!kmem_alloc_batch(&objects, cache, GFP_KERNEL))
1440                         goto free;
1441                 pool_push_batch(&pool_global, &objects);
1442         }
1443
1444         /* Disconnect the boot pool. */
1445         pool_boot.first = NULL;
1446
1447         /* Replace the active object references */
1448         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1449                 hlist_move_list(&db->list, &objects);
1450
1451                 hlist_for_each_entry(obj, &objects, node) {
1452                         struct debug_obj *new = pcpu_alloc();
1453
1454                         /* copy object data */
1455                         *new = *obj;
1456                         hlist_add_head(&new->node, &db->list);
1457                 }
1458         }
1459         return true;
1460 free:
1461         /* Can't use free_object_list() as the cache is not populated yet */
1462         hlist_for_each_entry_safe(obj, tmp, &pool_global.objects, node) {
1463                 hlist_del(&obj->node);
1464                 kmem_cache_free(cache, obj);
1465         }
1466         return false;
1467 }
1468
1469 /*
1470  * Called after the kmem_caches are functional to setup a dedicated
1471  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1472  * prevents that the debug code is called on kmem_cache_free() for the
1473  * debug tracker objects to avoid recursive calls.
1474  */
1475 void __init debug_objects_mem_init(void)
1476 {
1477         struct kmem_cache *cache;
1478         int extras;
1479
1480         if (!debug_objects_enabled)
1481                 return;
1482
1483         if (!debug_objects_selftest())
1484                 return;
1485
1486         cache = kmem_cache_create("debug_objects_cache", sizeof (struct debug_obj), 0,
1487                                   SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE, NULL);
1488
1489         if (!cache || !debug_objects_replace_static_objects(cache)) {
1490                 debug_objects_enabled = false;
1491                 pr_warn("Out of memory.\n");
1492                 return;
1493         }
1494
1495         /*
1496          * Adjust the thresholds for allocating and freeing objects
1497          * according to the number of possible CPUs available in the
1498          * system.
1499          */
1500         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1501         pool_global.max_cnt += extras;
1502         pool_global.min_cnt += extras;
1503
1504         /* Everything worked. Expose the cache */
1505         obj_cache = cache;
1506         static_branch_enable(&obj_cache_enabled);
1507
1508 #ifdef CONFIG_HOTPLUG_CPU
1509         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1510                                   object_cpu_offline);
1511 #endif
1512         return;
1513 }