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         if (limit < 5 && descr != descr_test) {
 505                 void *hint = descr->debug_hint ?
 506                         descr->debug_hint(obj->object) : NULL;
 507                 limit++;
 508                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 509                                  "object type: %s hint: %pS\n",
 510                         msg, obj_states[obj->state], obj->astate,
 511                         descr->name, hint);
 512         }
 513         debug_objects_warnings++;
 514 }
 515
 516 /*
 517  * Try to repair the damage, so we have a better chance to get useful
 518  * debug output.
 519  */
 520 static bool
 521 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 522                    void * addr, enum debug_obj_state state)
 523 {
 524         if (fixup && fixup(addr, state)) {
 525                 debug_objects_fixups++;
 526                 return true;
 527         }
 528         return false;
 529 }
 530
 531 static void debug_object_is_on_stack(void *addr, int onstack)
 532 {
 533         int is_on_stack;
 534         static int limit;
 535
 536         if (limit > 4)
 537                 return;
 538
 539         is_on_stack = object_is_on_stack(addr);
 540         if (is_on_stack == onstack)
 541                 return;
 542
 543         limit++;
 544         if (is_on_stack)
 545                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 546                          task_stack_page(current));
 547         else
 548                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 549                          task_stack_page(current));
 550
 551         WARN_ON(1);
 552 }
 553
 554 static struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
 555                                                 const struct debug_obj_descr *descr,
 556                                                 bool onstack, bool alloc_ifstatic)
 557 {
 558         struct debug_obj *obj = lookup_object(addr, b);
 559         enum debug_obj_state state = ODEBUG_STATE_NONE;
 560
 561         if (likely(obj))
 562                 return obj;
 563
 564         /*
 565          * debug_object_init() unconditionally allocates untracked
 566          * objects. It does not matter whether it is a static object or
 567          * not.
 568          *
 569          * debug_object_assert_init() and debug_object_activate() allow
 570          * allocation only if the descriptor callback confirms that the
 571          * object is static and considered initialized. For non-static
 572          * objects the allocation needs to be done from the fixup callback.
 573          */
 574         if (unlikely(alloc_ifstatic)) {
 575                 if (!descr->is_static_object || !descr->is_static_object(addr))
 576                         return ERR_PTR(-ENOENT);
 577                 /* Statically allocated objects are considered initialized */
 578                 state = ODEBUG_STATE_INIT;
 579         }
 580
 581         obj = alloc_object(addr, b, descr);
 582         if (likely(obj)) {
 583                 obj->state = state;
 584                 debug_object_is_on_stack(addr, onstack);
 585                 return obj;
 586         }
 587
 588         /* Out of memory. Do the cleanup outside of the locked region */
 589         debug_objects_enabled = 0;
 590         return NULL;
 591 }
 592
 593 static void
 594 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
 595 {
 596         enum debug_obj_state state;
 597         struct debug_bucket *db;
 598         struct debug_obj *obj;
 599         unsigned long flags;
 600
 601         /*
 602          * On RT enabled kernels the pool refill must happen in preemptible
 603          * context:
 604          */
 605         if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
 606                 fill_pool();
 607
 608         db = get_bucket((unsigned long) addr);
 609
 610         raw_spin_lock_irqsave(&db->lock, flags);
 611
 612         obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
 613         if (unlikely(!obj)) {
 614                 raw_spin_unlock_irqrestore(&db->lock, flags);
 615                 debug_objects_oom();
 616                 return;
 617         }
 618
 619         switch (obj->state) {
 620         case ODEBUG_STATE_NONE:
 621         case ODEBUG_STATE_INIT:
 622         case ODEBUG_STATE_INACTIVE:
 623                 obj->state = ODEBUG_STATE_INIT;
 624                 break;
 625
 626         case ODEBUG_STATE_ACTIVE:
 627                 state = obj->state;
 628                 raw_spin_unlock_irqrestore(&db->lock, flags);
 629                 debug_print_object(obj, "init");
 630                 debug_object_fixup(descr->fixup_init, addr, state);
 631                 return;
 632
 633         case ODEBUG_STATE_DESTROYED:
 634                 raw_spin_unlock_irqrestore(&db->lock, flags);
 635                 debug_print_object(obj, "init");
 636                 return;
 637         default:
 638                 break;
 639         }
 640
 641         raw_spin_unlock_irqrestore(&db->lock, flags);
 642 }
 643
 644 /**
 645  * debug_object_init - debug checks when an object is initialized
 646  * @addr:       address of the object
 647  * @descr:      pointer to an object specific debug description structure
 648  */
 649 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
 650 {
 651         if (!debug_objects_enabled)
 652                 return;
 653
 654         __debug_object_init(addr, descr, 0);
 655 }
 656 EXPORT_SYMBOL_GPL(debug_object_init);
 657
 658 /**
 659  * debug_object_init_on_stack - debug checks when an object on stack is
 660  *                              initialized
 661  * @addr:       address of the object
 662  * @descr:      pointer to an object specific debug description structure
 663  */
 664 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
 665 {
 666         if (!debug_objects_enabled)
 667                 return;
 668
 669         __debug_object_init(addr, descr, 1);
 670 }
 671 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 672
 673 /**
 674  * debug_object_activate - debug checks when an object is activated
 675  * @addr:       address of the object
 676  * @descr:      pointer to an object specific debug description structure
 677  * Returns 0 for success, -EINVAL for check failed.
 678  */
 679 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
 680 {
 681         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 682         enum debug_obj_state state;
 683         struct debug_bucket *db;
 684         struct debug_obj *obj;
 685         unsigned long flags;
 686         int ret;
 687
 688         if (!debug_objects_enabled)
 689                 return 0;
 690
 691         db = get_bucket((unsigned long) addr);
 692
 693         raw_spin_lock_irqsave(&db->lock, flags);
 694
 695         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 696         if (likely(!IS_ERR_OR_NULL(obj))) {
 697                 bool print_object = false;
 698
 699                 switch (obj->state) {
 700                 case ODEBUG_STATE_INIT:
 701                 case ODEBUG_STATE_INACTIVE:
 702                         obj->state = ODEBUG_STATE_ACTIVE;
 703                         ret = 0;
 704                         break;
 705
 706                 case ODEBUG_STATE_ACTIVE:
 707                         state = obj->state;
 708                         raw_spin_unlock_irqrestore(&db->lock, flags);
 709                         debug_print_object(obj, "activate");
 710                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 711                         return ret ? 0 : -EINVAL;
 712
 713                 case ODEBUG_STATE_DESTROYED:
 714                         print_object = true;
 715                         ret = -EINVAL;
 716                         break;
 717                 default:
 718                         ret = 0;
 719                         break;
 720                 }
 721                 raw_spin_unlock_irqrestore(&db->lock, flags);
 722                 if (print_object)
 723                         debug_print_object(obj, "activate");
 724                 return ret;
 725         }
 726
 727         raw_spin_unlock_irqrestore(&db->lock, flags);
 728
 729         /* If NULL the allocation has hit OOM */
 730         if (!obj) {
 731                 debug_objects_oom();
 732                 return 0;
 733         }
 734
 735         /* Object is neither static nor tracked. It's not initialized */
 736         debug_print_object(&o, "activate");
 737         ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE);
 738         return ret ? 0 : -EINVAL;
 739 }
 740 EXPORT_SYMBOL_GPL(debug_object_activate);
 741
 742 /**
 743  * debug_object_deactivate - debug checks when an object is deactivated
 744  * @addr:       address of the object
 745  * @descr:      pointer to an object specific debug description structure
 746  */
 747 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
 748 {
 749         struct debug_bucket *db;
 750         struct debug_obj *obj;
 751         unsigned long flags;
 752         bool print_object = false;
 753
 754         if (!debug_objects_enabled)
 755                 return;
 756
 757         db = get_bucket((unsigned long) addr);
 758
 759         raw_spin_lock_irqsave(&db->lock, flags);
 760
 761         obj = lookup_object(addr, db);
 762         if (obj) {
 763                 switch (obj->state) {
 764                 case ODEBUG_STATE_INIT:
 765                 case ODEBUG_STATE_INACTIVE:
 766                 case ODEBUG_STATE_ACTIVE:
 767                         if (!obj->astate)
 768                                 obj->state = ODEBUG_STATE_INACTIVE;
 769                         else
 770                                 print_object = true;
 771                         break;
 772
 773                 case ODEBUG_STATE_DESTROYED:
 774                         print_object = true;
 775                         break;
 776                 default:
 777                         break;
 778                 }
 779         }
 780
 781         raw_spin_unlock_irqrestore(&db->lock, flags);
 782         if (!obj) {
 783                 struct debug_obj o = { .object = addr,
 784                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 785                                        .descr = descr };
 786
 787                 debug_print_object(&o, "deactivate");
 788         } else if (print_object) {
 789                 debug_print_object(obj, "deactivate");
 790         }
 791 }
 792 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 793
 794 /**
 795  * debug_object_destroy - debug checks when an object is destroyed
 796  * @addr:       address of the object
 797  * @descr:      pointer to an object specific debug description structure
 798  */
 799 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
 800 {
 801         enum debug_obj_state state;
 802         struct debug_bucket *db;
 803         struct debug_obj *obj;
 804         unsigned long flags;
 805         bool print_object = false;
 806
 807         if (!debug_objects_enabled)
 808                 return;
 809
 810         db = get_bucket((unsigned long) addr);
 811
 812         raw_spin_lock_irqsave(&db->lock, flags);
 813
 814         obj = lookup_object(addr, db);
 815         if (!obj)
 816                 goto out_unlock;
 817
 818         switch (obj->state) {
 819         case ODEBUG_STATE_NONE:
 820         case ODEBUG_STATE_INIT:
 821         case ODEBUG_STATE_INACTIVE:
 822                 obj->state = ODEBUG_STATE_DESTROYED;
 823                 break;
 824         case ODEBUG_STATE_ACTIVE:
 825                 state = obj->state;
 826                 raw_spin_unlock_irqrestore(&db->lock, flags);
 827                 debug_print_object(obj, "destroy");
 828                 debug_object_fixup(descr->fixup_destroy, addr, state);
 829                 return;
 830
 831         case ODEBUG_STATE_DESTROYED:
 832                 print_object = true;
 833                 break;
 834         default:
 835                 break;
 836         }
 837 out_unlock:
 838         raw_spin_unlock_irqrestore(&db->lock, flags);
 839         if (print_object)
 840                 debug_print_object(obj, "destroy");
 841 }
 842 EXPORT_SYMBOL_GPL(debug_object_destroy);
 843
 844 /**
 845  * debug_object_free - debug checks when an object is freed
 846  * @addr:       address of the object
 847  * @descr:      pointer to an object specific debug description structure
 848  */
 849 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
 850 {
 851         enum debug_obj_state state;
 852         struct debug_bucket *db;
 853         struct debug_obj *obj;
 854         unsigned long flags;
 855
 856         if (!debug_objects_enabled)
 857                 return;
 858
 859         db = get_bucket((unsigned long) addr);
 860
 861         raw_spin_lock_irqsave(&db->lock, flags);
 862
 863         obj = lookup_object(addr, db);
 864         if (!obj)
 865                 goto out_unlock;
 866
 867         switch (obj->state) {
 868         case ODEBUG_STATE_ACTIVE:
 869                 state = obj->state;
 870                 raw_spin_unlock_irqrestore(&db->lock, flags);
 871                 debug_print_object(obj, "free");
 872                 debug_object_fixup(descr->fixup_free, addr, state);
 873                 return;
 874         default:
 875                 hlist_del(&obj->node);
 876                 raw_spin_unlock_irqrestore(&db->lock, flags);
 877                 free_object(obj);
 878                 return;
 879         }
 880 out_unlock:
 881         raw_spin_unlock_irqrestore(&db->lock, flags);
 882 }
 883 EXPORT_SYMBOL_GPL(debug_object_free);
 884
 885 /**
 886  * debug_object_assert_init - debug checks when object should be init-ed
 887  * @addr:       address of the object
 888  * @descr:      pointer to an object specific debug description structure
 889  */
 890 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
 891 {
 892         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 893         struct debug_bucket *db;
 894         struct debug_obj *obj;
 895         unsigned long flags;
 896
 897         if (!debug_objects_enabled)
 898                 return;
 899
 900         db = get_bucket((unsigned long) addr);
 901
 902         raw_spin_lock_irqsave(&db->lock, flags);
 903         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 904         raw_spin_unlock_irqrestore(&db->lock, flags);
 905         if (likely(!IS_ERR_OR_NULL(obj)))
 906                 return;
 907
 908         /* If NULL the allocation has hit OOM */
 909         if (!obj) {
 910                 debug_objects_oom();
 911                 return;
 912         }
 913
 914         /* Object is neither tracked nor static. It's not initialized. */
 915         debug_print_object(&o, "assert_init");
 916         debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
 917 }
 918 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 919
 920 /**
 921  * debug_object_active_state - debug checks object usage state machine
 922  * @addr:       address of the object
 923  * @descr:      pointer to an object specific debug description structure
 924  * @expect:     expected state
 925  * @next:       state to move to if expected state is found
 926  */
 927 void
 928 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
 929                           unsigned int expect, unsigned int next)
 930 {
 931         struct debug_bucket *db;
 932         struct debug_obj *obj;
 933         unsigned long flags;
 934         bool print_object = false;
 935
 936         if (!debug_objects_enabled)
 937                 return;
 938
 939         db = get_bucket((unsigned long) addr);
 940
 941         raw_spin_lock_irqsave(&db->lock, flags);
 942
 943         obj = lookup_object(addr, db);
 944         if (obj) {
 945                 switch (obj->state) {
 946                 case ODEBUG_STATE_ACTIVE:
 947                         if (obj->astate == expect)
 948                                 obj->astate = next;
 949                         else
 950                                 print_object = true;
 951                         break;
 952
 953                 default:
 954                         print_object = true;
 955                         break;
 956                 }
 957         }
 958
 959         raw_spin_unlock_irqrestore(&db->lock, flags);
 960         if (!obj) {
 961                 struct debug_obj o = { .object = addr,
 962                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 963                                        .descr = descr };
 964
 965                 debug_print_object(&o, "active_state");
 966         } else if (print_object) {
 967                 debug_print_object(obj, "active_state");
 968         }
 969 }
 970 EXPORT_SYMBOL_GPL(debug_object_active_state);
 971
 972 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 973 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 974 {
 975         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 976         const struct debug_obj_descr *descr;
 977         enum debug_obj_state state;
 978         struct debug_bucket *db;
 979         struct hlist_node *tmp;
 980         struct debug_obj *obj;
 981         int cnt, objs_checked = 0;
 982
 983         saddr = (unsigned long) address;
 984         eaddr = saddr + size;
 985         paddr = saddr & ODEBUG_CHUNK_MASK;
 986         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 987         chunks >>= ODEBUG_CHUNK_SHIFT;
 988
 989         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 990                 db = get_bucket(paddr);
 991
 992 repeat:
 993                 cnt = 0;
 994                 raw_spin_lock_irqsave(&db->lock, flags);
 995                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 996                         cnt++;
 997                         oaddr = (unsigned long) obj->object;
 998                         if (oaddr < saddr || oaddr >= eaddr)
 999                                 continue;
1000
1001                         switch (obj->state) {
1002                         case ODEBUG_STATE_ACTIVE:
1003                                 descr = obj->descr;
1004                                 state = obj->state;
1005                                 raw_spin_unlock_irqrestore(&db->lock, flags);
1006                                 debug_print_object(obj, "free");
1007                                 debug_object_fixup(descr->fixup_free,
1008                                                    (void *) oaddr, state);
1009                                 goto repeat;
1010                         default:
1011                                 hlist_del(&obj->node);
1012                                 __free_object(obj);
1013                                 break;
1014                         }
1015                 }
1016                 raw_spin_unlock_irqrestore(&db->lock, flags);
1017
1018                 if (cnt > debug_objects_maxchain)
1019                         debug_objects_maxchain = cnt;
1020
1021                 objs_checked += cnt;
1022         }
1023
1024         if (objs_checked > debug_objects_maxchecked)
1025                 debug_objects_maxchecked = objs_checked;
1026
1027         /* Schedule work to actually kmem_cache_free() objects */
1028         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1029                 WRITE_ONCE(obj_freeing, true);
1030                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1031         }
1032 }
1033
1034 void debug_check_no_obj_freed(const void *address, unsigned long size)
1035 {
1036         if (debug_objects_enabled)
1037                 __debug_check_no_obj_freed(address, size);
1038 }
1039 #endif
1040
1041 #ifdef CONFIG_DEBUG_FS
1042
1043 static int debug_stats_show(struct seq_file *m, void *v)
1044 {
1045         int cpu, obj_percpu_free = 0;
1046
1047         for_each_possible_cpu(cpu)
1048                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1049
1050         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1051         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1052         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1053         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1054         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1055         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1056         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1057         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1058         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1059         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1060         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1061         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1062         return 0;
1063 }
1064 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1065
1066 static int __init debug_objects_init_debugfs(void)
1067 {
1068         struct dentry *dbgdir;
1069
1070         if (!debug_objects_enabled)
1071                 return 0;
1072
1073         dbgdir = debugfs_create_dir("debug_objects", NULL);
1074
1075         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1076
1077         return 0;
1078 }
1079 __initcall(debug_objects_init_debugfs);
1080
1081 #else
1082 static inline void debug_objects_init_debugfs(void) { }
1083 #endif
1084
1085 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1086
1087 /* Random data structure for the self test */
1088 struct self_test {
1089         unsigned long   dummy1[6];
1090         int             static_init;
1091         unsigned long   dummy2[3];
1092 };
1093
1094 static __initconst const struct debug_obj_descr descr_type_test;
1095
1096 static bool __init is_static_object(void *addr)
1097 {
1098         struct self_test *obj = addr;
1099
1100         return obj->static_init;
1101 }
1102
1103 /*
1104  * fixup_init is called when:
1105  * - an active object is initialized
1106  */
1107 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1108 {
1109         struct self_test *obj = addr;
1110
1111         switch (state) {
1112         case ODEBUG_STATE_ACTIVE:
1113                 debug_object_deactivate(obj, &descr_type_test);
1114                 debug_object_init(obj, &descr_type_test);
1115                 return true;
1116         default:
1117                 return false;
1118         }
1119 }
1120
1121 /*
1122  * fixup_activate is called when:
1123  * - an active object is activated
1124  * - an unknown non-static object is activated
1125  */
1126 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1127 {
1128         struct self_test *obj = addr;
1129
1130         switch (state) {
1131         case ODEBUG_STATE_NOTAVAILABLE:
1132                 return true;
1133         case ODEBUG_STATE_ACTIVE:
1134                 debug_object_deactivate(obj, &descr_type_test);
1135                 debug_object_activate(obj, &descr_type_test);
1136                 return true;
1137
1138         default:
1139                 return false;
1140         }
1141 }
1142
1143 /*
1144  * fixup_destroy is called when:
1145  * - an active object is destroyed
1146  */
1147 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1148 {
1149         struct self_test *obj = addr;
1150
1151         switch (state) {
1152         case ODEBUG_STATE_ACTIVE:
1153                 debug_object_deactivate(obj, &descr_type_test);
1154                 debug_object_destroy(obj, &descr_type_test);
1155                 return true;
1156         default:
1157                 return false;
1158         }
1159 }
1160
1161 /*
1162  * fixup_free is called when:
1163  * - an active object is freed
1164  */
1165 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1166 {
1167         struct self_test *obj = addr;
1168
1169         switch (state) {
1170         case ODEBUG_STATE_ACTIVE:
1171                 debug_object_deactivate(obj, &descr_type_test);
1172                 debug_object_free(obj, &descr_type_test);
1173                 return true;
1174         default:
1175                 return false;
1176         }
1177 }
1178
1179 static int __init
1180 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1181 {
1182         struct debug_bucket *db;
1183         struct debug_obj *obj;
1184         unsigned long flags;
1185         int res = -EINVAL;
1186
1187         db = get_bucket((unsigned long) addr);
1188
1189         raw_spin_lock_irqsave(&db->lock, flags);
1190
1191         obj = lookup_object(addr, db);
1192         if (!obj && state != ODEBUG_STATE_NONE) {
1193                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1194                 goto out;
1195         }
1196         if (obj && obj->state != state) {
1197                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1198                        obj->state, state);
1199                 goto out;
1200         }
1201         if (fixups != debug_objects_fixups) {
1202                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1203                        fixups, debug_objects_fixups);
1204                 goto out;
1205         }
1206         if (warnings != debug_objects_warnings) {
1207                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1208                        warnings, debug_objects_warnings);
1209                 goto out;
1210         }
1211         res = 0;
1212 out:
1213         raw_spin_unlock_irqrestore(&db->lock, flags);
1214         if (res)
1215                 debug_objects_enabled = 0;
1216         return res;
1217 }
1218
1219 static __initconst const struct debug_obj_descr descr_type_test = {
1220         .name                   = "selftest",
1221         .is_static_object       = is_static_object,
1222         .fixup_init             = fixup_init,
1223         .fixup_activate         = fixup_activate,
1224         .fixup_destroy          = fixup_destroy,
1225         .fixup_free             = fixup_free,
1226 };
1227
1228 static __initdata struct self_test obj = { .static_init = 0 };
1229
1230 static void __init debug_objects_selftest(void)
1231 {
1232         int fixups, oldfixups, warnings, oldwarnings;
1233         unsigned long flags;
1234
1235         local_irq_save(flags);
1236
1237         fixups = oldfixups = debug_objects_fixups;
1238         warnings = oldwarnings = debug_objects_warnings;
1239         descr_test = &descr_type_test;
1240
1241         debug_object_init(&obj, &descr_type_test);
1242         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1243                 goto out;
1244         debug_object_activate(&obj, &descr_type_test);
1245         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1246                 goto out;
1247         debug_object_activate(&obj, &descr_type_test);
1248         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1249                 goto out;
1250         debug_object_deactivate(&obj, &descr_type_test);
1251         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1252                 goto out;
1253         debug_object_destroy(&obj, &descr_type_test);
1254         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1255                 goto out;
1256         debug_object_init(&obj, &descr_type_test);
1257         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1258                 goto out;
1259         debug_object_activate(&obj, &descr_type_test);
1260         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1261                 goto out;
1262         debug_object_deactivate(&obj, &descr_type_test);
1263         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1264                 goto out;
1265         debug_object_free(&obj, &descr_type_test);
1266         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1267                 goto out;
1268
1269         obj.static_init = 1;
1270         debug_object_activate(&obj, &descr_type_test);
1271         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1272                 goto out;
1273         debug_object_init(&obj, &descr_type_test);
1274         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1275                 goto out;
1276         debug_object_free(&obj, &descr_type_test);
1277         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1278                 goto out;
1279
1280 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1281         debug_object_init(&obj, &descr_type_test);
1282         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1283                 goto out;
1284         debug_object_activate(&obj, &descr_type_test);
1285         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1286                 goto out;
1287         __debug_check_no_obj_freed(&obj, sizeof(obj));
1288         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1289                 goto out;
1290 #endif
1291         pr_info("selftest passed\n");
1292
1293 out:
1294         debug_objects_fixups = oldfixups;
1295         debug_objects_warnings = oldwarnings;
1296         descr_test = NULL;
1297
1298         local_irq_restore(flags);
1299 }
1300 #else
1301 static inline void debug_objects_selftest(void) { }
1302 #endif
1303
1304 /*
1305  * Called during early boot to initialize the hash buckets and link
1306  * the static object pool objects into the poll list. After this call
1307  * the object tracker is fully operational.
1308  */
1309 void __init debug_objects_early_init(void)
1310 {
1311         int i;
1312
1313         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1314                 raw_spin_lock_init(&obj_hash[i].lock);
1315
1316         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1317                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1318 }
1319
1320 /*
1321  * Convert the statically allocated objects to dynamic ones:
1322  */
1323 static int __init debug_objects_replace_static_objects(void)
1324 {
1325         struct debug_bucket *db = obj_hash;
1326         struct hlist_node *tmp;
1327         struct debug_obj *obj, *new;
1328         HLIST_HEAD(objects);
1329         int i, cnt = 0;
1330
1331         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1332                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1333                 if (!obj)
1334                         goto free;
1335                 hlist_add_head(&obj->node, &objects);
1336         }
1337
1338         debug_objects_allocated += i;
1339
1340         /*
1341          * debug_objects_mem_init() is now called early that only one CPU is up
1342          * and interrupts have been disabled, so it is safe to replace the
1343          * active object references.
1344          */
1345
1346         /* Remove the statically allocated objects from the pool */
1347         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1348                 hlist_del(&obj->node);
1349         /* Move the allocated objects to the pool */
1350         hlist_move_list(&objects, &obj_pool);
1351
1352         /* Replace the active object references */
1353         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1354                 hlist_move_list(&db->list, &objects);
1355
1356                 hlist_for_each_entry(obj, &objects, node) {
1357                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1358                         hlist_del(&new->node);
1359                         /* copy object data */
1360                         *new = *obj;
1361                         hlist_add_head(&new->node, &db->list);
1362                         cnt++;
1363                 }
1364         }
1365
1366         pr_debug("%d of %d active objects replaced\n",
1367                  cnt, obj_pool_used);
1368         return 0;
1369 free:
1370         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1371                 hlist_del(&obj->node);
1372                 kmem_cache_free(obj_cache, obj);
1373         }
1374         return -ENOMEM;
1375 }
1376
1377 /*
1378  * Called after the kmem_caches are functional to setup a dedicated
1379  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1380  * prevents that the debug code is called on kmem_cache_free() for the
1381  * debug tracker objects to avoid recursive calls.
1382  */
1383 void __init debug_objects_mem_init(void)
1384 {
1385         int cpu, extras;
1386
1387         if (!debug_objects_enabled)
1388                 return;
1389
1390         /*
1391          * Initialize the percpu object pools
1392          *
1393          * Initialization is not strictly necessary, but was done for
1394          * completeness.
1395          */
1396         for_each_possible_cpu(cpu)
1397                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1398
1399         obj_cache = kmem_cache_create("debug_objects_cache",
1400                                       sizeof (struct debug_obj), 0,
1401                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1402                                       NULL);
1403
1404         if (!obj_cache || debug_objects_replace_static_objects()) {
1405                 debug_objects_enabled = 0;
1406                 kmem_cache_destroy(obj_cache);
1407                 pr_warn("out of memory.\n");
1408                 return;
1409         } else
1410                 debug_objects_selftest();
1411
1412 #ifdef CONFIG_HOTPLUG_CPU
1413         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1414                                         object_cpu_offline);
1415 #endif
1416
1417         /*
1418          * Increase the thresholds for allocating and freeing objects
1419          * according to the number of possible CPUs available in the system.
1420          */
1421         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1422         debug_objects_pool_size += extras;
1423         debug_objects_pool_min_level += extras;
1424 }