lib/debugobjects.c

   1 /*
   2  * Generic infrastructure for lifetime debugging of objects.
   3  *
   4  * Started by Thomas Gleixner
   5  *
   6  * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
   7  *
   8  * For licencing details see kernel-base/COPYING
   9  */
  10
  11 #define pr_fmt(fmt) "ODEBUG: " fmt
  12
  13 #include <linux/debugobjects.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/sched.h>
  16 #include <linux/sched/task_stack.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/slab.h>
  20 #include <linux/hash.h>
  21 #include <linux/kmemleak.h>
  22 #include <linux/cpu.h>
  23
  24 #define ODEBUG_HASH_BITS        14
  25 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  26
  27 #define ODEBUG_POOL_SIZE        1024
  28 #define ODEBUG_POOL_MIN_LEVEL   256
  29 #define ODEBUG_POOL_PERCPU_SIZE 64
  30 #define ODEBUG_BATCH_SIZE       16
  31
  32 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  33 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  34 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  35
  36 /*
  37  * We limit the freeing of debug objects via workqueue at a maximum
  38  * frequency of 10Hz and about 1024 objects for each freeing operation.
  39  * So it is freeing at most 10k debug objects per second.
  40  */
  41 #define ODEBUG_FREE_WORK_MAX    1024
  42 #define ODEBUG_FREE_WORK_DELAY  DIV_ROUND_UP(HZ, 10)
  43
  44 struct debug_bucket {
  45         struct hlist_head       list;
  46         raw_spinlock_t          lock;
  47 };
  48
  49 /*
  50  * Debug object percpu free list
  51  * Access is protected by disabling irq
  52  */
  53 struct debug_percpu_free {
  54         struct hlist_head       free_objs;
  55         int                     obj_free;
  56 };
  57
  58 static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
  59
  60 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  61
  62 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  63
  64 static DEFINE_RAW_SPINLOCK(pool_lock);
  65
  66 static HLIST_HEAD(obj_pool);
  67 static HLIST_HEAD(obj_to_free);
  68
  69 /*
  70  * Because of the presence of percpu free pools, obj_pool_free will
  71  * under-count those in the percpu free pools. Similarly, obj_pool_used
  72  * will over-count those in the percpu free pools. Adjustments will be
  73  * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
  74  * can be off.
  75  */
  76 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  77 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  78 static int                      obj_pool_used;
  79 static int                      obj_pool_max_used;
  80 static bool                     obj_freeing;
  81 /* The number of objs on the global free list */
  82 static int                      obj_nr_tofree;
  83
  84 static int                      debug_objects_maxchain __read_mostly;
  85 static int __maybe_unused       debug_objects_maxchecked __read_mostly;
  86 static int                      debug_objects_fixups __read_mostly;
  87 static int                      debug_objects_warnings __read_mostly;
  88 static int                      debug_objects_enabled __read_mostly
  89                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  90 static int                      debug_objects_pool_size __read_mostly
  91                                 = ODEBUG_POOL_SIZE;
  92 static int                      debug_objects_pool_min_level __read_mostly
  93                                 = ODEBUG_POOL_MIN_LEVEL;
  94 static const struct debug_obj_descr *descr_test  __read_mostly;
  95 static struct kmem_cache        *obj_cache __read_mostly;
  96
  97 /*
  98  * Track numbers of kmem_cache_alloc()/free() calls done.
  99  */
 100 static int                      debug_objects_allocated;
 101 static int                      debug_objects_freed;
 102
 103 static void free_obj_work(struct work_struct *work);
 104 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
 105
 106 static int __init enable_object_debug(char *str)
 107 {
 108         debug_objects_enabled = 1;
 109         return 0;
 110 }
 111
 112 static int __init disable_object_debug(char *str)
 113 {
 114         debug_objects_enabled = 0;
 115         return 0;
 116 }
 117
 118 early_param("debug_objects", enable_object_debug);
 119 early_param("no_debug_objects", disable_object_debug);
 120
 121 static const char *obj_states[ODEBUG_STATE_MAX] = {
 122         [ODEBUG_STATE_NONE]             = "none",
 123         [ODEBUG_STATE_INIT]             = "initialized",
 124         [ODEBUG_STATE_INACTIVE]         = "inactive",
 125         [ODEBUG_STATE_ACTIVE]           = "active",
 126         [ODEBUG_STATE_DESTROYED]        = "destroyed",
 127         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
 128 };
 129
 130 static void fill_pool(void)
 131 {
 132         gfp_t gfp = __GFP_HIGH | __GFP_NOWARN;
 133         struct debug_obj *obj;
 134         unsigned long flags;
 135
 136         if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
 137                 return;
 138
 139         /*
 140          * Reuse objs from the global free list; they will be reinitialized
 141          * when allocating.
 142          *
 143          * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
 144          * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
 145          * sections.
 146          */
 147         while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
 148                 raw_spin_lock_irqsave(&pool_lock, flags);
 149                 /*
 150                  * Recheck with the lock held as the worker thread might have
 151                  * won the race and freed the global free list already.
 152                  */
 153                 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 154                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 155                         hlist_del(&obj->node);
 156                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 157                         hlist_add_head(&obj->node, &obj_pool);
 158                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 159                 }
 160                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 161         }
 162
 163         if (unlikely(!obj_cache))
 164                 return;
 165
 166         while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
 167                 struct debug_obj *new[ODEBUG_BATCH_SIZE];
 168                 int cnt;
 169
 170                 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
 171                         new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
 172                         if (!new[cnt])
 173                                 break;
 174                 }
 175                 if (!cnt)
 176                         return;
 177
 178                 raw_spin_lock_irqsave(&pool_lock, flags);
 179                 while (cnt) {
 180                         hlist_add_head(&new[--cnt]->node, &obj_pool);
 181                         debug_objects_allocated++;
 182                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 183                 }
 184                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 185         }
 186 }
 187
 188 /*
 189  * Lookup an object in the hash bucket.
 190  */
 191 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 192 {
 193         struct debug_obj *obj;
 194         int cnt = 0;
 195
 196         hlist_for_each_entry(obj, &b->list, node) {
 197                 cnt++;
 198                 if (obj->object == addr)
 199                         return obj;
 200         }
 201         if (cnt > debug_objects_maxchain)
 202                 debug_objects_maxchain = cnt;
 203
 204         return NULL;
 205 }
 206
 207 /*
 208  * Allocate a new object from the hlist
 209  */
 210 static struct debug_obj *__alloc_object(struct hlist_head *list)
 211 {
 212         struct debug_obj *obj = NULL;
 213
 214         if (list->first) {
 215                 obj = hlist_entry(list->first, typeof(*obj), node);
 216                 hlist_del(&obj->node);
 217         }
 218
 219         return obj;
 220 }
 221
 222 static struct debug_obj *
 223 alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
 224 {
 225         struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 226         struct debug_obj *obj;
 227
 228         if (likely(obj_cache)) {
 229                 obj = __alloc_object(&percpu_pool->free_objs);
 230                 if (obj) {
 231                         percpu_pool->obj_free--;
 232                         goto init_obj;
 233                 }
 234         }
 235
 236         raw_spin_lock(&pool_lock);
 237         obj = __alloc_object(&obj_pool);
 238         if (obj) {
 239                 obj_pool_used++;
 240                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 241
 242                 /*
 243                  * Looking ahead, allocate one batch of debug objects and
 244                  * put them into the percpu free pool.
 245                  */
 246                 if (likely(obj_cache)) {
 247                         int i;
 248
 249                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 250                                 struct debug_obj *obj2;
 251
 252                                 obj2 = __alloc_object(&obj_pool);
 253                                 if (!obj2)
 254                                         break;
 255                                 hlist_add_head(&obj2->node,
 256                                                &percpu_pool->free_objs);
 257                                 percpu_pool->obj_free++;
 258                                 obj_pool_used++;
 259                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 260                         }
 261                 }
 262
 263                 if (obj_pool_used > obj_pool_max_used)
 264                         obj_pool_max_used = obj_pool_used;
 265
 266                 if (obj_pool_free < obj_pool_min_free)
 267                         obj_pool_min_free = obj_pool_free;
 268         }
 269         raw_spin_unlock(&pool_lock);
 270
 271 init_obj:
 272         if (obj) {
 273                 obj->object = addr;
 274                 obj->descr  = descr;
 275                 obj->state  = ODEBUG_STATE_NONE;
 276                 obj->astate = 0;
 277                 hlist_add_head(&obj->node, &b->list);
 278         }
 279         return obj;
 280 }
 281
 282 /*
 283  * workqueue function to free objects.
 284  *
 285  * To reduce contention on the global pool_lock, the actual freeing of
 286  * debug objects will be delayed if the pool_lock is busy.
 287  */
 288 static void free_obj_work(struct work_struct *work)
 289 {
 290         struct hlist_node *tmp;
 291         struct debug_obj *obj;
 292         unsigned long flags;
 293         HLIST_HEAD(tofree);
 294
 295         WRITE_ONCE(obj_freeing, false);
 296         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 297                 return;
 298
 299         if (obj_pool_free >= debug_objects_pool_size)
 300                 goto free_objs;
 301
 302         /*
 303          * The objs on the pool list might be allocated before the work is
 304          * run, so recheck if pool list it full or not, if not fill pool
 305          * list from the global free list. As it is likely that a workload
 306          * may be gearing up to use more and more objects, don't free any
 307          * of them until the next round.
 308          */
 309         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 310                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 311                 hlist_del(&obj->node);
 312                 hlist_add_head(&obj->node, &obj_pool);
 313                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 314                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 315         }
 316         raw_spin_unlock_irqrestore(&pool_lock, flags);
 317         return;
 318
 319 free_objs:
 320         /*
 321          * Pool list is already full and there are still objs on the free
 322          * list. Move remaining free objs to a temporary list to free the
 323          * memory outside the pool_lock held region.
 324          */
 325         if (obj_nr_tofree) {
 326                 hlist_move_list(&obj_to_free, &tofree);
 327                 debug_objects_freed += obj_nr_tofree;
 328                 WRITE_ONCE(obj_nr_tofree, 0);
 329         }
 330         raw_spin_unlock_irqrestore(&pool_lock, flags);
 331
 332         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 333                 hlist_del(&obj->node);
 334                 kmem_cache_free(obj_cache, obj);
 335         }
 336 }
 337
 338 static void __free_object(struct debug_obj *obj)
 339 {
 340         struct debug_obj *objs[ODEBUG_BATCH_SIZE];
 341         struct debug_percpu_free *percpu_pool;
 342         int lookahead_count = 0;
 343         unsigned long flags;
 344         bool work;
 345
 346         local_irq_save(flags);
 347         if (!obj_cache)
 348                 goto free_to_obj_pool;
 349
 350         /*
 351          * Try to free it into the percpu pool first.
 352          */
 353         percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 354         if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
 355                 hlist_add_head(&obj->node, &percpu_pool->free_objs);
 356                 percpu_pool->obj_free++;
 357                 local_irq_restore(flags);
 358                 return;
 359         }
 360
 361         /*
 362          * As the percpu pool is full, look ahead and pull out a batch
 363          * of objects from the percpu pool and free them as well.
 364          */
 365         for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
 366                 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
 367                 if (!objs[lookahead_count])
 368                         break;
 369                 percpu_pool->obj_free--;
 370         }
 371
 372 free_to_obj_pool:
 373         raw_spin_lock(&pool_lock);
 374         work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
 375                (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
 376         obj_pool_used--;
 377
 378         if (work) {
 379                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 380                 hlist_add_head(&obj->node, &obj_to_free);
 381                 if (lookahead_count) {
 382                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
 383                         obj_pool_used -= lookahead_count;
 384                         while (lookahead_count) {
 385                                 hlist_add_head(&objs[--lookahead_count]->node,
 386                                                &obj_to_free);
 387                         }
 388                 }
 389
 390                 if ((obj_pool_free > debug_objects_pool_size) &&
 391                     (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
 392                         int i;
 393
 394                         /*
 395                          * Free one more batch of objects from obj_pool.
 396                          */
 397                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 398                                 obj = __alloc_object(&obj_pool);
 399                                 hlist_add_head(&obj->node, &obj_to_free);
 400                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 401                                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 402                         }
 403                 }
 404         } else {
 405                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 406                 hlist_add_head(&obj->node, &obj_pool);
 407                 if (lookahead_count) {
 408                         WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
 409                         obj_pool_used -= lookahead_count;
 410                         while (lookahead_count) {
 411                                 hlist_add_head(&objs[--lookahead_count]->node,
 412                                                &obj_pool);
 413                         }
 414                 }
 415         }
 416         raw_spin_unlock(&pool_lock);
 417         local_irq_restore(flags);
 418 }
 419
 420 /*
 421  * Put the object back into the pool and schedule work to free objects
 422  * if necessary.
 423  */
 424 static void free_object(struct debug_obj *obj)
 425 {
 426         __free_object(obj);
 427         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
 428                 WRITE_ONCE(obj_freeing, true);
 429                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
 430         }
 431 }
 432
 433 #ifdef CONFIG_HOTPLUG_CPU
 434 static int object_cpu_offline(unsigned int cpu)
 435 {
 436         struct debug_percpu_free *percpu_pool;
 437         struct hlist_node *tmp;
 438         struct debug_obj *obj;
 439         unsigned long flags;
 440
 441         /* Remote access is safe as the CPU is dead already */
 442         percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
 443         hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
 444                 hlist_del(&obj->node);
 445                 kmem_cache_free(obj_cache, obj);
 446         }
 447
 448         raw_spin_lock_irqsave(&pool_lock, flags);
 449         obj_pool_used -= percpu_pool->obj_free;
 450         debug_objects_freed += percpu_pool->obj_free;
 451         raw_spin_unlock_irqrestore(&pool_lock, flags);
 452
 453         percpu_pool->obj_free = 0;
 454
 455         return 0;
 456 }
 457 #endif
 458
 459 /*
 460  * We run out of memory. That means we probably have tons of objects
 461  * allocated.
 462  */
 463 static void debug_objects_oom(void)
 464 {
 465         struct debug_bucket *db = obj_hash;
 466         struct hlist_node *tmp;
 467         HLIST_HEAD(freelist);
 468         struct debug_obj *obj;
 469         unsigned long flags;
 470         int i;
 471
 472         pr_warn("Out of memory. ODEBUG disabled\n");
 473
 474         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 475                 raw_spin_lock_irqsave(&db->lock, flags);
 476                 hlist_move_list(&db->list, &freelist);
 477                 raw_spin_unlock_irqrestore(&db->lock, flags);
 478
 479                 /* Now free them */
 480                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 481                         hlist_del(&obj->node);
 482                         free_object(obj);
 483                 }
 484         }
 485 }
 486
 487 /*
 488  * We use the pfn of the address for the hash. That way we can check
 489  * for freed objects simply by checking the affected bucket.
 490  */
 491 static struct debug_bucket *get_bucket(unsigned long addr)
 492 {
 493         unsigned long hash;
 494
 495         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 496         return &obj_hash[hash];
 497 }
 498
 499 static void debug_print_object(struct debug_obj *obj, char *msg)
 500 {
 501         const struct debug_obj_descr *descr = obj->descr;
 502         static int limit;
 503
 504         /*
 505          * Don't report if lookup_object_or_alloc() by the current thread
 506          * failed because lookup_object_or_alloc()/debug_objects_oom() by a
 507          * concurrent thread turned off debug_objects_enabled and cleared
 508          * the hash buckets.
 509          */
 510         if (!debug_objects_enabled)
 511                 return;
 512
 513         if (limit < 5 && descr != descr_test) {
 514                 void *hint = descr->debug_hint ?
 515                         descr->debug_hint(obj->object) : NULL;
 516                 limit++;
 517                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 518                                  "object type: %s hint: %pS\n",
 519                         msg, obj_states[obj->state], obj->astate,
 520                         descr->name, hint);
 521         }
 522         debug_objects_warnings++;
 523 }
 524
 525 /*
 526  * Try to repair the damage, so we have a better chance to get useful
 527  * debug output.
 528  */
 529 static bool
 530 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 531                    void * addr, enum debug_obj_state state)
 532 {
 533         if (fixup && fixup(addr, state)) {
 534                 debug_objects_fixups++;
 535                 return true;
 536         }
 537         return false;
 538 }
 539
 540 static void debug_object_is_on_stack(void *addr, int onstack)
 541 {
 542         int is_on_stack;
 543         static int limit;
 544
 545         if (limit > 4)
 546                 return;
 547
 548         is_on_stack = object_is_on_stack(addr);
 549         if (is_on_stack == onstack)
 550                 return;
 551
 552         limit++;
 553         if (is_on_stack)
 554                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 555                          task_stack_page(current));
 556         else
 557                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 558                          task_stack_page(current));
 559
 560         WARN_ON(1);
 561 }
 562
 563 static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
 564                                                 const struct debug_obj_descr *descr,
 565                                                 bool onstack, bool alloc_ifstatic)
 566 {
 567         struct debug_obj *obj = lookup_object(addr, b);
 568         enum debug_obj_state state = ODEBUG_STATE_NONE;
 569
 570         if (likely(obj))
 571                 return obj;
 572
 573         /*
 574          * debug_object_init() unconditionally allocates untracked
 575          * objects. It does not matter whether it is a static object or
 576          * not.
 577          *
 578          * debug_object_assert_init() and debug_object_activate() allow
 579          * allocation only if the descriptor callback confirms that the
 580          * object is static and considered initialized. For non-static
 581          * objects the allocation needs to be done from the fixup callback.
 582          */
 583         if (unlikely(alloc_ifstatic)) {
 584                 if (!descr->is_static_object || !descr->is_static_object(addr))
 585                         return ERR_PTR(-ENOENT);
 586                 /* Statically allocated objects are considered initialized */
 587                 state = ODEBUG_STATE_INIT;
 588         }
 589
 590         obj = alloc_object(addr, b, descr);
 591         if (likely(obj)) {
 592                 obj->state = state;
 593                 debug_object_is_on_stack(addr, onstack);
 594                 return obj;
 595         }
 596
 597         /* Out of memory. Do the cleanup outside of the locked region */
 598         debug_objects_enabled = 0;
 599         return NULL;
 600 }
 601
 602 static void debug_objects_fill_pool(void)
 603 {
 604         /*
 605          * On RT enabled kernels the pool refill must happen in preemptible
 606          * context:
 607          */
 608         if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
 609                 fill_pool();
 610 }
 611
 612 static void
 613 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
 614 {
 615         struct debug_obj *obj, o;
 616         struct debug_bucket *db;
 617         unsigned long flags;
 618
 619         debug_objects_fill_pool();
 620
 621         db = get_bucket((unsigned long) addr);
 622
 623         raw_spin_lock_irqsave(&db->lock, flags);
 624
 625         obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
 626         if (unlikely(!obj)) {
 627                 raw_spin_unlock_irqrestore(&db->lock, flags);
 628                 debug_objects_oom();
 629                 return;
 630         }
 631
 632         switch (obj->state) {
 633         case ODEBUG_STATE_NONE:
 634         case ODEBUG_STATE_INIT:
 635         case ODEBUG_STATE_INACTIVE:
 636                 obj->state = ODEBUG_STATE_INIT;
 637                 raw_spin_unlock_irqrestore(&db->lock, flags);
 638                 return;
 639         default:
 640                 break;
 641         }
 642
 643         o = *obj;
 644         raw_spin_unlock_irqrestore(&db->lock, flags);
 645         debug_print_object(&o, "init");
 646
 647         if (o.state == ODEBUG_STATE_ACTIVE)
 648                 debug_object_fixup(descr->fixup_init, addr, o.state);
 649 }
 650
 651 /**
 652  * debug_object_init - debug checks when an object is initialized
 653  * @addr:       address of the object
 654  * @descr:      pointer to an object specific debug description structure
 655  */
 656 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
 657 {
 658         if (!debug_objects_enabled)
 659                 return;
 660
 661         __debug_object_init(addr, descr, 0);
 662 }
 663 EXPORT_SYMBOL_GPL(debug_object_init);
 664
 665 /**
 666  * debug_object_init_on_stack - debug checks when an object on stack is
 667  *                              initialized
 668  * @addr:       address of the object
 669  * @descr:      pointer to an object specific debug description structure
 670  */
 671 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
 672 {
 673         if (!debug_objects_enabled)
 674                 return;
 675
 676         __debug_object_init(addr, descr, 1);
 677 }
 678 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 679
 680 /**
 681  * debug_object_activate - debug checks when an object is activated
 682  * @addr:       address of the object
 683  * @descr:      pointer to an object specific debug description structure
 684  * Returns 0 for success, -EINVAL for check failed.
 685  */
 686 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
 687 {
 688         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 689         struct debug_bucket *db;
 690         struct debug_obj *obj;
 691         unsigned long flags;
 692
 693         if (!debug_objects_enabled)
 694                 return 0;
 695
 696         debug_objects_fill_pool();
 697
 698         db = get_bucket((unsigned long) addr);
 699
 700         raw_spin_lock_irqsave(&db->lock, flags);
 701
 702         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 703         if (unlikely(!obj)) {
 704                 raw_spin_unlock_irqrestore(&db->lock, flags);
 705                 debug_objects_oom();
 706                 return 0;
 707         } else if (likely(!IS_ERR(obj))) {
 708                 switch (obj->state) {
 709                 case ODEBUG_STATE_ACTIVE:
 710                 case ODEBUG_STATE_DESTROYED:
 711                         o = *obj;
 712                         break;
 713                 case ODEBUG_STATE_INIT:
 714                 case ODEBUG_STATE_INACTIVE:
 715                         obj->state = ODEBUG_STATE_ACTIVE;
 716                         fallthrough;
 717                 default:
 718                         raw_spin_unlock_irqrestore(&db->lock, flags);
 719                         return 0;
 720                 }
 721         }
 722
 723         raw_spin_unlock_irqrestore(&db->lock, flags);
 724         debug_print_object(&o, "activate");
 725
 726         switch (o.state) {
 727         case ODEBUG_STATE_ACTIVE:
 728         case ODEBUG_STATE_NOTAVAILABLE:
 729                 if (debug_object_fixup(descr->fixup_activate, addr, o.state))
 730                         return 0;
 731                 fallthrough;
 732         default:
 733                 return -EINVAL;
 734         }
 735 }
 736 EXPORT_SYMBOL_GPL(debug_object_activate);
 737
 738 /**
 739  * debug_object_deactivate - debug checks when an object is deactivated
 740  * @addr:       address of the object
 741  * @descr:      pointer to an object specific debug description structure
 742  */
 743 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
 744 {
 745         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 746         struct debug_bucket *db;
 747         struct debug_obj *obj;
 748         unsigned long flags;
 749
 750         if (!debug_objects_enabled)
 751                 return;
 752
 753         db = get_bucket((unsigned long) addr);
 754
 755         raw_spin_lock_irqsave(&db->lock, flags);
 756
 757         obj = lookup_object(addr, db);
 758         if (obj) {
 759                 switch (obj->state) {
 760                 case ODEBUG_STATE_DESTROYED:
 761                         break;
 762                 case ODEBUG_STATE_INIT:
 763                 case ODEBUG_STATE_INACTIVE:
 764                 case ODEBUG_STATE_ACTIVE:
 765                         if (obj->astate)
 766                                 break;
 767                         obj->state = ODEBUG_STATE_INACTIVE;
 768                         fallthrough;
 769                 default:
 770                         raw_spin_unlock_irqrestore(&db->lock, flags);
 771                         return;
 772                 }
 773                 o = *obj;
 774         }
 775
 776         raw_spin_unlock_irqrestore(&db->lock, flags);
 777         debug_print_object(&o, "deactivate");
 778 }
 779 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 780
 781 /**
 782  * debug_object_destroy - debug checks when an object is destroyed
 783  * @addr:       address of the object
 784  * @descr:      pointer to an object specific debug description structure
 785  */
 786 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
 787 {
 788         struct debug_obj *obj, o;
 789         struct debug_bucket *db;
 790         unsigned long flags;
 791
 792         if (!debug_objects_enabled)
 793                 return;
 794
 795         db = get_bucket((unsigned long) addr);
 796
 797         raw_spin_lock_irqsave(&db->lock, flags);
 798
 799         obj = lookup_object(addr, db);
 800         if (!obj) {
 801                 raw_spin_unlock_irqrestore(&db->lock, flags);
 802                 return;
 803         }
 804
 805         switch (obj->state) {
 806         case ODEBUG_STATE_ACTIVE:
 807         case ODEBUG_STATE_DESTROYED:
 808                 break;
 809         case ODEBUG_STATE_NONE:
 810         case ODEBUG_STATE_INIT:
 811         case ODEBUG_STATE_INACTIVE:
 812                 obj->state = ODEBUG_STATE_DESTROYED;
 813                 fallthrough;
 814         default:
 815                 raw_spin_unlock_irqrestore(&db->lock, flags);
 816                 return;
 817         }
 818
 819         o = *obj;
 820         raw_spin_unlock_irqrestore(&db->lock, flags);
 821         debug_print_object(&o, "destroy");
 822
 823         if (o.state == ODEBUG_STATE_ACTIVE)
 824                 debug_object_fixup(descr->fixup_destroy, addr, o.state);
 825 }
 826 EXPORT_SYMBOL_GPL(debug_object_destroy);
 827
 828 /**
 829  * debug_object_free - debug checks when an object is freed
 830  * @addr:       address of the object
 831  * @descr:      pointer to an object specific debug description structure
 832  */
 833 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
 834 {
 835         struct debug_obj *obj, o;
 836         struct debug_bucket *db;
 837         unsigned long flags;
 838
 839         if (!debug_objects_enabled)
 840                 return;
 841
 842         db = get_bucket((unsigned long) addr);
 843
 844         raw_spin_lock_irqsave(&db->lock, flags);
 845
 846         obj = lookup_object(addr, db);
 847         if (!obj) {
 848                 raw_spin_unlock_irqrestore(&db->lock, flags);
 849                 return;
 850         }
 851
 852         switch (obj->state) {
 853         case ODEBUG_STATE_ACTIVE:
 854                 break;
 855         default:
 856                 hlist_del(&obj->node);
 857                 raw_spin_unlock_irqrestore(&db->lock, flags);
 858                 free_object(obj);
 859                 return;
 860         }
 861
 862         o = *obj;
 863         raw_spin_unlock_irqrestore(&db->lock, flags);
 864         debug_print_object(&o, "free");
 865
 866         debug_object_fixup(descr->fixup_free, addr, o.state);
 867 }
 868 EXPORT_SYMBOL_GPL(debug_object_free);
 869
 870 /**
 871  * debug_object_assert_init - debug checks when object should be init-ed
 872  * @addr:       address of the object
 873  * @descr:      pointer to an object specific debug description structure
 874  */
 875 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
 876 {
 877         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 878         struct debug_bucket *db;
 879         struct debug_obj *obj;
 880         unsigned long flags;
 881
 882         if (!debug_objects_enabled)
 883                 return;
 884
 885         debug_objects_fill_pool();
 886
 887         db = get_bucket((unsigned long) addr);
 888
 889         raw_spin_lock_irqsave(&db->lock, flags);
 890         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 891         raw_spin_unlock_irqrestore(&db->lock, flags);
 892         if (likely(!IS_ERR_OR_NULL(obj)))
 893                 return;
 894
 895         /* If NULL the allocation has hit OOM */
 896         if (!obj) {
 897                 debug_objects_oom();
 898                 return;
 899         }
 900
 901         /* Object is neither tracked nor static. It's not initialized. */
 902         debug_print_object(&o, "assert_init");
 903         debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
 904 }
 905 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 906
 907 /**
 908  * debug_object_active_state - debug checks object usage state machine
 909  * @addr:       address of the object
 910  * @descr:      pointer to an object specific debug description structure
 911  * @expect:     expected state
 912  * @next:       state to move to if expected state is found
 913  */
 914 void
 915 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
 916                           unsigned int expect, unsigned int next)
 917 {
 918         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 919         struct debug_bucket *db;
 920         struct debug_obj *obj;
 921         unsigned long flags;
 922
 923         if (!debug_objects_enabled)
 924                 return;
 925
 926         db = get_bucket((unsigned long) addr);
 927
 928         raw_spin_lock_irqsave(&db->lock, flags);
 929
 930         obj = lookup_object(addr, db);
 931         if (obj) {
 932                 switch (obj->state) {
 933                 case ODEBUG_STATE_ACTIVE:
 934                         if (obj->astate != expect)
 935                                 break;
 936                         obj->astate = next;
 937                         raw_spin_unlock_irqrestore(&db->lock, flags);
 938                         return;
 939                 default:
 940                         break;
 941                 }
 942                 o = *obj;
 943         }
 944
 945         raw_spin_unlock_irqrestore(&db->lock, flags);
 946         debug_print_object(&o, "active_state");
 947 }
 948 EXPORT_SYMBOL_GPL(debug_object_active_state);
 949
 950 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 951 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 952 {
 953         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 954         int cnt, objs_checked = 0;
 955         struct debug_obj *obj, o;
 956         struct debug_bucket *db;
 957         struct hlist_node *tmp;
 958
 959         saddr = (unsigned long) address;
 960         eaddr = saddr + size;
 961         paddr = saddr & ODEBUG_CHUNK_MASK;
 962         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 963         chunks >>= ODEBUG_CHUNK_SHIFT;
 964
 965         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 966                 db = get_bucket(paddr);
 967
 968 repeat:
 969                 cnt = 0;
 970                 raw_spin_lock_irqsave(&db->lock, flags);
 971                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 972                         cnt++;
 973                         oaddr = (unsigned long) obj->object;
 974                         if (oaddr < saddr || oaddr >= eaddr)
 975                                 continue;
 976
 977                         switch (obj->state) {
 978                         case ODEBUG_STATE_ACTIVE:
 979                                 o = *obj;
 980                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 981                                 debug_print_object(&o, "free");
 982                                 debug_object_fixup(o.descr->fixup_free, (void *)oaddr, o.state);
 983                                 goto repeat;
 984                         default:
 985                                 hlist_del(&obj->node);
 986                                 __free_object(obj);
 987                                 break;
 988                         }
 989                 }
 990                 raw_spin_unlock_irqrestore(&db->lock, flags);
 991
 992                 if (cnt > debug_objects_maxchain)
 993                         debug_objects_maxchain = cnt;
 994
 995                 objs_checked += cnt;
 996         }
 997
 998         if (objs_checked > debug_objects_maxchecked)
 999                 debug_objects_maxchecked = objs_checked;
1000
1001         /* Schedule work to actually kmem_cache_free() objects */
1002         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1003                 WRITE_ONCE(obj_freeing, true);
1004                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1005         }
1006 }
1007
1008 void debug_check_no_obj_freed(const void *address, unsigned long size)
1009 {
1010         if (debug_objects_enabled)
1011                 __debug_check_no_obj_freed(address, size);
1012 }
1013 #endif
1014
1015 #ifdef CONFIG_DEBUG_FS
1016
1017 static int debug_stats_show(struct seq_file *m, void *v)
1018 {
1019         int cpu, obj_percpu_free = 0;
1020
1021         for_each_possible_cpu(cpu)
1022                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1023
1024         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1025         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1026         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1027         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1028         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1029         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1030         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1031         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1032         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1033         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1034         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1035         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1036         return 0;
1037 }
1038 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1039
1040 static int __init debug_objects_init_debugfs(void)
1041 {
1042         struct dentry *dbgdir;
1043
1044         if (!debug_objects_enabled)
1045                 return 0;
1046
1047         dbgdir = debugfs_create_dir("debug_objects", NULL);
1048
1049         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1050
1051         return 0;
1052 }
1053 __initcall(debug_objects_init_debugfs);
1054
1055 #else
1056 static inline void debug_objects_init_debugfs(void) { }
1057 #endif
1058
1059 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1060
1061 /* Random data structure for the self test */
1062 struct self_test {
1063         unsigned long   dummy1[6];
1064         int             static_init;
1065         unsigned long   dummy2[3];
1066 };
1067
1068 static __initconst const struct debug_obj_descr descr_type_test;
1069
1070 static bool __init is_static_object(void *addr)
1071 {
1072         struct self_test *obj = addr;
1073
1074         return obj->static_init;
1075 }
1076
1077 /*
1078  * fixup_init is called when:
1079  * - an active object is initialized
1080  */
1081 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1082 {
1083         struct self_test *obj = addr;
1084
1085         switch (state) {
1086         case ODEBUG_STATE_ACTIVE:
1087                 debug_object_deactivate(obj, &descr_type_test);
1088                 debug_object_init(obj, &descr_type_test);
1089                 return true;
1090         default:
1091                 return false;
1092         }
1093 }
1094
1095 /*
1096  * fixup_activate is called when:
1097  * - an active object is activated
1098  * - an unknown non-static object is activated
1099  */
1100 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1101 {
1102         struct self_test *obj = addr;
1103
1104         switch (state) {
1105         case ODEBUG_STATE_NOTAVAILABLE:
1106                 return true;
1107         case ODEBUG_STATE_ACTIVE:
1108                 debug_object_deactivate(obj, &descr_type_test);
1109                 debug_object_activate(obj, &descr_type_test);
1110                 return true;
1111
1112         default:
1113                 return false;
1114         }
1115 }
1116
1117 /*
1118  * fixup_destroy is called when:
1119  * - an active object is destroyed
1120  */
1121 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1122 {
1123         struct self_test *obj = addr;
1124
1125         switch (state) {
1126         case ODEBUG_STATE_ACTIVE:
1127                 debug_object_deactivate(obj, &descr_type_test);
1128                 debug_object_destroy(obj, &descr_type_test);
1129                 return true;
1130         default:
1131                 return false;
1132         }
1133 }
1134
1135 /*
1136  * fixup_free is called when:
1137  * - an active object is freed
1138  */
1139 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1140 {
1141         struct self_test *obj = addr;
1142
1143         switch (state) {
1144         case ODEBUG_STATE_ACTIVE:
1145                 debug_object_deactivate(obj, &descr_type_test);
1146                 debug_object_free(obj, &descr_type_test);
1147                 return true;
1148         default:
1149                 return false;
1150         }
1151 }
1152
1153 static int __init
1154 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1155 {
1156         struct debug_bucket *db;
1157         struct debug_obj *obj;
1158         unsigned long flags;
1159         int res = -EINVAL;
1160
1161         db = get_bucket((unsigned long) addr);
1162
1163         raw_spin_lock_irqsave(&db->lock, flags);
1164
1165         obj = lookup_object(addr, db);
1166         if (!obj && state != ODEBUG_STATE_NONE) {
1167                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1168                 goto out;
1169         }
1170         if (obj && obj->state != state) {
1171                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1172                        obj->state, state);
1173                 goto out;
1174         }
1175         if (fixups != debug_objects_fixups) {
1176                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1177                        fixups, debug_objects_fixups);
1178                 goto out;
1179         }
1180         if (warnings != debug_objects_warnings) {
1181                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1182                        warnings, debug_objects_warnings);
1183                 goto out;
1184         }
1185         res = 0;
1186 out:
1187         raw_spin_unlock_irqrestore(&db->lock, flags);
1188         if (res)
1189                 debug_objects_enabled = 0;
1190         return res;
1191 }
1192
1193 static __initconst const struct debug_obj_descr descr_type_test = {
1194         .name                   = "selftest",
1195         .is_static_object       = is_static_object,
1196         .fixup_init             = fixup_init,
1197         .fixup_activate         = fixup_activate,
1198         .fixup_destroy          = fixup_destroy,
1199         .fixup_free             = fixup_free,
1200 };
1201
1202 static __initdata struct self_test obj = { .static_init = 0 };
1203
1204 static void __init debug_objects_selftest(void)
1205 {
1206         int fixups, oldfixups, warnings, oldwarnings;
1207         unsigned long flags;
1208
1209         local_irq_save(flags);
1210
1211         fixups = oldfixups = debug_objects_fixups;
1212         warnings = oldwarnings = debug_objects_warnings;
1213         descr_test = &descr_type_test;
1214
1215         debug_object_init(&obj, &descr_type_test);
1216         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1217                 goto out;
1218         debug_object_activate(&obj, &descr_type_test);
1219         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1220                 goto out;
1221         debug_object_activate(&obj, &descr_type_test);
1222         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1223                 goto out;
1224         debug_object_deactivate(&obj, &descr_type_test);
1225         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1226                 goto out;
1227         debug_object_destroy(&obj, &descr_type_test);
1228         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1229                 goto out;
1230         debug_object_init(&obj, &descr_type_test);
1231         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1232                 goto out;
1233         debug_object_activate(&obj, &descr_type_test);
1234         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1235                 goto out;
1236         debug_object_deactivate(&obj, &descr_type_test);
1237         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1238                 goto out;
1239         debug_object_free(&obj, &descr_type_test);
1240         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1241                 goto out;
1242
1243         obj.static_init = 1;
1244         debug_object_activate(&obj, &descr_type_test);
1245         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1246                 goto out;
1247         debug_object_init(&obj, &descr_type_test);
1248         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1249                 goto out;
1250         debug_object_free(&obj, &descr_type_test);
1251         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1252                 goto out;
1253
1254 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1255         debug_object_init(&obj, &descr_type_test);
1256         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1257                 goto out;
1258         debug_object_activate(&obj, &descr_type_test);
1259         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1260                 goto out;
1261         __debug_check_no_obj_freed(&obj, sizeof(obj));
1262         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1263                 goto out;
1264 #endif
1265         pr_info("selftest passed\n");
1266
1267 out:
1268         debug_objects_fixups = oldfixups;
1269         debug_objects_warnings = oldwarnings;
1270         descr_test = NULL;
1271
1272         local_irq_restore(flags);
1273 }
1274 #else
1275 static inline void debug_objects_selftest(void) { }
1276 #endif
1277
1278 /*
1279  * Called during early boot to initialize the hash buckets and link
1280  * the static object pool objects into the poll list. After this call
1281  * the object tracker is fully operational.
1282  */
1283 void __init debug_objects_early_init(void)
1284 {
1285         int i;
1286
1287         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1288                 raw_spin_lock_init(&obj_hash[i].lock);
1289
1290         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1291                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1292 }
1293
1294 /*
1295  * Convert the statically allocated objects to dynamic ones:
1296  */
1297 static int __init debug_objects_replace_static_objects(void)
1298 {
1299         struct debug_bucket *db = obj_hash;
1300         struct hlist_node *tmp;
1301         struct debug_obj *obj, *new;
1302         HLIST_HEAD(objects);
1303         int i, cnt = 0;
1304
1305         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1306                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1307                 if (!obj)
1308                         goto free;
1309                 hlist_add_head(&obj->node, &objects);
1310         }
1311
1312         debug_objects_allocated += i;
1313
1314         /*
1315          * debug_objects_mem_init() is now called early that only one CPU is up
1316          * and interrupts have been disabled, so it is safe to replace the
1317          * active object references.
1318          */
1319
1320         /* Remove the statically allocated objects from the pool */
1321         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1322                 hlist_del(&obj->node);
1323         /* Move the allocated objects to the pool */
1324         hlist_move_list(&objects, &obj_pool);
1325
1326         /* Replace the active object references */
1327         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1328                 hlist_move_list(&db->list, &objects);
1329
1330                 hlist_for_each_entry(obj, &objects, node) {
1331                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1332                         hlist_del(&new->node);
1333                         /* copy object data */
1334                         *new = *obj;
1335                         hlist_add_head(&new->node, &db->list);
1336                         cnt++;
1337                 }
1338         }
1339
1340         pr_debug("%d of %d active objects replaced\n",
1341                  cnt, obj_pool_used);
1342         return 0;
1343 free:
1344         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1345                 hlist_del(&obj->node);
1346                 kmem_cache_free(obj_cache, obj);
1347         }
1348         return -ENOMEM;
1349 }
1350
1351 /*
1352  * Called after the kmem_caches are functional to setup a dedicated
1353  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1354  * prevents that the debug code is called on kmem_cache_free() for the
1355  * debug tracker objects to avoid recursive calls.
1356  */
1357 void __init debug_objects_mem_init(void)
1358 {
1359         int cpu, extras;
1360
1361         if (!debug_objects_enabled)
1362                 return;
1363
1364         /*
1365          * Initialize the percpu object pools
1366          *
1367          * Initialization is not strictly necessary, but was done for
1368          * completeness.
1369          */
1370         for_each_possible_cpu(cpu)
1371                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1372
1373         obj_cache = kmem_cache_create("debug_objects_cache",
1374                                       sizeof (struct debug_obj), 0,
1375                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1376                                       NULL);
1377
1378         if (!obj_cache || debug_objects_replace_static_objects()) {
1379                 debug_objects_enabled = 0;
1380                 kmem_cache_destroy(obj_cache);
1381                 pr_warn("out of memory.\n");
1382                 return;
1383         } else
1384                 debug_objects_selftest();
1385
1386 #ifdef CONFIG_HOTPLUG_CPU
1387         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1388                                         object_cpu_offline);
1389 #endif
1390
1391         /*
1392          * Increase the thresholds for allocating and freeing objects
1393          * according to the number of possible CPUs available in the system.
1394          */
1395         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1396         debug_objects_pool_size += extras;
1397         debug_objects_pool_min_level += extras;
1398 }