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_ATOMIC | __GFP_NORETRY | __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 /*
 223  * Allocate a new object. If the pool is empty, switch off the debugger.
 224  * Must be called with interrupts disabled.
 225  */
 226 static struct debug_obj *
 227 alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
 228 {
 229         struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 230         struct debug_obj *obj;
 231
 232         if (likely(obj_cache)) {
 233                 obj = __alloc_object(&percpu_pool->free_objs);
 234                 if (obj) {
 235                         percpu_pool->obj_free--;
 236                         goto init_obj;
 237                 }
 238         }
 239
 240         raw_spin_lock(&pool_lock);
 241         obj = __alloc_object(&obj_pool);
 242         if (obj) {
 243                 obj_pool_used++;
 244                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 245
 246                 /*
 247                  * Looking ahead, allocate one batch of debug objects and
 248                  * put them into the percpu free pool.
 249                  */
 250                 if (likely(obj_cache)) {
 251                         int i;
 252
 253                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 254                                 struct debug_obj *obj2;
 255
 256                                 obj2 = __alloc_object(&obj_pool);
 257                                 if (!obj2)
 258                                         break;
 259                                 hlist_add_head(&obj2->node,
 260                                                &percpu_pool->free_objs);
 261                                 percpu_pool->obj_free++;
 262                                 obj_pool_used++;
 263                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 264                         }
 265                 }
 266
 267                 if (obj_pool_used > obj_pool_max_used)
 268                         obj_pool_max_used = obj_pool_used;
 269
 270                 if (obj_pool_free < obj_pool_min_free)
 271                         obj_pool_min_free = obj_pool_free;
 272         }
 273         raw_spin_unlock(&pool_lock);
 274
 275 init_obj:
 276         if (obj) {
 277                 obj->object = addr;
 278                 obj->descr  = descr;
 279                 obj->state  = ODEBUG_STATE_NONE;
 280                 obj->astate = 0;
 281                 hlist_add_head(&obj->node, &b->list);
 282         }
 283         return obj;
 284 }
 285
 286 /*
 287  * workqueue function to free objects.
 288  *
 289  * To reduce contention on the global pool_lock, the actual freeing of
 290  * debug objects will be delayed if the pool_lock is busy.
 291  */
 292 static void free_obj_work(struct work_struct *work)
 293 {
 294         struct hlist_node *tmp;
 295         struct debug_obj *obj;
 296         unsigned long flags;
 297         HLIST_HEAD(tofree);
 298
 299         WRITE_ONCE(obj_freeing, false);
 300         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 301                 return;
 302
 303         if (obj_pool_free >= debug_objects_pool_size)
 304                 goto free_objs;
 305
 306         /*
 307          * The objs on the pool list might be allocated before the work is
 308          * run, so recheck if pool list it full or not, if not fill pool
 309          * list from the global free list. As it is likely that a workload
 310          * may be gearing up to use more and more objects, don't free any
 311          * of them until the next round.
 312          */
 313         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 314                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 315                 hlist_del(&obj->node);
 316                 hlist_add_head(&obj->node, &obj_pool);
 317                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 318                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 319         }
 320         raw_spin_unlock_irqrestore(&pool_lock, flags);
 321         return;
 322
 323 free_objs:
 324         /*
 325          * Pool list is already full and there are still objs on the free
 326          * list. Move remaining free objs to a temporary list to free the
 327          * memory outside the pool_lock held region.
 328          */
 329         if (obj_nr_tofree) {
 330                 hlist_move_list(&obj_to_free, &tofree);
 331                 debug_objects_freed += obj_nr_tofree;
 332                 WRITE_ONCE(obj_nr_tofree, 0);
 333         }
 334         raw_spin_unlock_irqrestore(&pool_lock, flags);
 335
 336         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 337                 hlist_del(&obj->node);
 338                 kmem_cache_free(obj_cache, obj);
 339         }
 340 }
 341
 342 static void __free_object(struct debug_obj *obj)
 343 {
 344         struct debug_obj *objs[ODEBUG_BATCH_SIZE];
 345         struct debug_percpu_free *percpu_pool;
 346         int lookahead_count = 0;
 347         unsigned long flags;
 348         bool work;
 349
 350         local_irq_save(flags);
 351         if (!obj_cache)
 352                 goto free_to_obj_pool;
 353
 354         /*
 355          * Try to free it into the percpu pool first.
 356          */
 357         percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 358         if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
 359                 hlist_add_head(&obj->node, &percpu_pool->free_objs);
 360                 percpu_pool->obj_free++;
 361                 local_irq_restore(flags);
 362                 return;
 363         }
 364
 365         /*
 366          * As the percpu pool is full, look ahead and pull out a batch
 367          * of objects from the percpu pool and free them as well.
 368          */
 369         for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
 370                 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
 371                 if (!objs[lookahead_count])
 372                         break;
 373                 percpu_pool->obj_free--;
 374         }
 375
 376 free_to_obj_pool:
 377         raw_spin_lock(&pool_lock);
 378         work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
 379                (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
 380         obj_pool_used--;
 381
 382         if (work) {
 383                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 384                 hlist_add_head(&obj->node, &obj_to_free);
 385                 if (lookahead_count) {
 386                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
 387                         obj_pool_used -= lookahead_count;
 388                         while (lookahead_count) {
 389                                 hlist_add_head(&objs[--lookahead_count]->node,
 390                                                &obj_to_free);
 391                         }
 392                 }
 393
 394                 if ((obj_pool_free > debug_objects_pool_size) &&
 395                     (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
 396                         int i;
 397
 398                         /*
 399                          * Free one more batch of objects from obj_pool.
 400                          */
 401                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 402                                 obj = __alloc_object(&obj_pool);
 403                                 hlist_add_head(&obj->node, &obj_to_free);
 404                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 405                                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 406                         }
 407                 }
 408         } else {
 409                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 410                 hlist_add_head(&obj->node, &obj_pool);
 411                 if (lookahead_count) {
 412                         WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
 413                         obj_pool_used -= lookahead_count;
 414                         while (lookahead_count) {
 415                                 hlist_add_head(&objs[--lookahead_count]->node,
 416                                                &obj_pool);
 417                         }
 418                 }
 419         }
 420         raw_spin_unlock(&pool_lock);
 421         local_irq_restore(flags);
 422 }
 423
 424 /*
 425  * Put the object back into the pool and schedule work to free objects
 426  * if necessary.
 427  */
 428 static void free_object(struct debug_obj *obj)
 429 {
 430         __free_object(obj);
 431         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
 432                 WRITE_ONCE(obj_freeing, true);
 433                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
 434         }
 435 }
 436
 437 #ifdef CONFIG_HOTPLUG_CPU
 438 static int object_cpu_offline(unsigned int cpu)
 439 {
 440         struct debug_percpu_free *percpu_pool;
 441         struct hlist_node *tmp;
 442         struct debug_obj *obj;
 443
 444         /* Remote access is safe as the CPU is dead already */
 445         percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
 446         hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
 447                 hlist_del(&obj->node);
 448                 kmem_cache_free(obj_cache, obj);
 449         }
 450         percpu_pool->obj_free = 0;
 451
 452         return 0;
 453 }
 454 #endif
 455
 456 /*
 457  * We run out of memory. That means we probably have tons of objects
 458  * allocated.
 459  */
 460 static void debug_objects_oom(void)
 461 {
 462         struct debug_bucket *db = obj_hash;
 463         struct hlist_node *tmp;
 464         HLIST_HEAD(freelist);
 465         struct debug_obj *obj;
 466         unsigned long flags;
 467         int i;
 468
 469         pr_warn("Out of memory. ODEBUG disabled\n");
 470
 471         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 472                 raw_spin_lock_irqsave(&db->lock, flags);
 473                 hlist_move_list(&db->list, &freelist);
 474                 raw_spin_unlock_irqrestore(&db->lock, flags);
 475
 476                 /* Now free them */
 477                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 478                         hlist_del(&obj->node);
 479                         free_object(obj);
 480                 }
 481         }
 482 }
 483
 484 /*
 485  * We use the pfn of the address for the hash. That way we can check
 486  * for freed objects simply by checking the affected bucket.
 487  */
 488 static struct debug_bucket *get_bucket(unsigned long addr)
 489 {
 490         unsigned long hash;
 491
 492         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 493         return &obj_hash[hash];
 494 }
 495
 496 static void debug_print_object(struct debug_obj *obj, char *msg)
 497 {
 498         const struct debug_obj_descr *descr = obj->descr;
 499         static int limit;
 500
 501         if (limit < 5 && descr != descr_test) {
 502                 void *hint = descr->debug_hint ?
 503                         descr->debug_hint(obj->object) : NULL;
 504                 limit++;
 505                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 506                                  "object type: %s hint: %pS\n",
 507                         msg, obj_states[obj->state], obj->astate,
 508                         descr->name, hint);
 509         }
 510         debug_objects_warnings++;
 511 }
 512
 513 /*
 514  * Try to repair the damage, so we have a better chance to get useful
 515  * debug output.
 516  */
 517 static bool
 518 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 519                    void * addr, enum debug_obj_state state)
 520 {
 521         if (fixup && fixup(addr, state)) {
 522                 debug_objects_fixups++;
 523                 return true;
 524         }
 525         return false;
 526 }
 527
 528 static void debug_object_is_on_stack(void *addr, int onstack)
 529 {
 530         int is_on_stack;
 531         static int limit;
 532
 533         if (limit > 4)
 534                 return;
 535
 536         is_on_stack = object_is_on_stack(addr);
 537         if (is_on_stack == onstack)
 538                 return;
 539
 540         limit++;
 541         if (is_on_stack)
 542                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 543                          task_stack_page(current));
 544         else
 545                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 546                          task_stack_page(current));
 547
 548         WARN_ON(1);
 549 }
 550
 551 static void
 552 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
 553 {
 554         enum debug_obj_state state;
 555         bool check_stack = false;
 556         struct debug_bucket *db;
 557         struct debug_obj *obj;
 558         unsigned long flags;
 559
 560         fill_pool();
 561
 562         db = get_bucket((unsigned long) addr);
 563
 564         raw_spin_lock_irqsave(&db->lock, flags);
 565
 566         obj = lookup_object(addr, db);
 567         if (!obj) {
 568                 obj = alloc_object(addr, db, descr);
 569                 if (!obj) {
 570                         debug_objects_enabled = 0;
 571                         raw_spin_unlock_irqrestore(&db->lock, flags);
 572                         debug_objects_oom();
 573                         return;
 574                 }
 575                 check_stack = true;
 576         }
 577
 578         switch (obj->state) {
 579         case ODEBUG_STATE_NONE:
 580         case ODEBUG_STATE_INIT:
 581         case ODEBUG_STATE_INACTIVE:
 582                 obj->state = ODEBUG_STATE_INIT;
 583                 break;
 584
 585         case ODEBUG_STATE_ACTIVE:
 586                 state = obj->state;
 587                 raw_spin_unlock_irqrestore(&db->lock, flags);
 588                 debug_print_object(obj, "init");
 589                 debug_object_fixup(descr->fixup_init, addr, state);
 590                 return;
 591
 592         case ODEBUG_STATE_DESTROYED:
 593                 raw_spin_unlock_irqrestore(&db->lock, flags);
 594                 debug_print_object(obj, "init");
 595                 return;
 596         default:
 597                 break;
 598         }
 599
 600         raw_spin_unlock_irqrestore(&db->lock, flags);
 601         if (check_stack)
 602                 debug_object_is_on_stack(addr, onstack);
 603 }
 604
 605 /**
 606  * debug_object_init - debug checks when an object is initialized
 607  * @addr:       address of the object
 608  * @descr:      pointer to an object specific debug description structure
 609  */
 610 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
 611 {
 612         if (!debug_objects_enabled)
 613                 return;
 614
 615         __debug_object_init(addr, descr, 0);
 616 }
 617 EXPORT_SYMBOL_GPL(debug_object_init);
 618
 619 /**
 620  * debug_object_init_on_stack - debug checks when an object on stack is
 621  *                              initialized
 622  * @addr:       address of the object
 623  * @descr:      pointer to an object specific debug description structure
 624  */
 625 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
 626 {
 627         if (!debug_objects_enabled)
 628                 return;
 629
 630         __debug_object_init(addr, descr, 1);
 631 }
 632 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 633
 634 /**
 635  * debug_object_activate - debug checks when an object is activated
 636  * @addr:       address of the object
 637  * @descr:      pointer to an object specific debug description structure
 638  * Returns 0 for success, -EINVAL for check failed.
 639  */
 640 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
 641 {
 642         enum debug_obj_state state;
 643         struct debug_bucket *db;
 644         struct debug_obj *obj;
 645         unsigned long flags;
 646         int ret;
 647         struct debug_obj o = { .object = addr,
 648                                .state = ODEBUG_STATE_NOTAVAILABLE,
 649                                .descr = descr };
 650
 651         if (!debug_objects_enabled)
 652                 return 0;
 653
 654         db = get_bucket((unsigned long) addr);
 655
 656         raw_spin_lock_irqsave(&db->lock, flags);
 657
 658         obj = lookup_object(addr, db);
 659         if (obj) {
 660                 bool print_object = false;
 661
 662                 switch (obj->state) {
 663                 case ODEBUG_STATE_INIT:
 664                 case ODEBUG_STATE_INACTIVE:
 665                         obj->state = ODEBUG_STATE_ACTIVE;
 666                         ret = 0;
 667                         break;
 668
 669                 case ODEBUG_STATE_ACTIVE:
 670                         state = obj->state;
 671                         raw_spin_unlock_irqrestore(&db->lock, flags);
 672                         debug_print_object(obj, "activate");
 673                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 674                         return ret ? 0 : -EINVAL;
 675
 676                 case ODEBUG_STATE_DESTROYED:
 677                         print_object = true;
 678                         ret = -EINVAL;
 679                         break;
 680                 default:
 681                         ret = 0;
 682                         break;
 683                 }
 684                 raw_spin_unlock_irqrestore(&db->lock, flags);
 685                 if (print_object)
 686                         debug_print_object(obj, "activate");
 687                 return ret;
 688         }
 689
 690         raw_spin_unlock_irqrestore(&db->lock, flags);
 691
 692         /*
 693          * We are here when a static object is activated. We
 694          * let the type specific code confirm whether this is
 695          * true or not. if true, we just make sure that the
 696          * static object is tracked in the object tracker. If
 697          * not, this must be a bug, so we try to fix it up.
 698          */
 699         if (descr->is_static_object && descr->is_static_object(addr)) {
 700                 /* track this static object */
 701                 debug_object_init(addr, descr);
 702                 debug_object_activate(addr, descr);
 703         } else {
 704                 debug_print_object(&o, "activate");
 705                 ret = debug_object_fixup(descr->fixup_activate, addr,
 706                                         ODEBUG_STATE_NOTAVAILABLE);
 707                 return ret ? 0 : -EINVAL;
 708         }
 709         return 0;
 710 }
 711 EXPORT_SYMBOL_GPL(debug_object_activate);
 712
 713 /**
 714  * debug_object_deactivate - debug checks when an object is deactivated
 715  * @addr:       address of the object
 716  * @descr:      pointer to an object specific debug description structure
 717  */
 718 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
 719 {
 720         struct debug_bucket *db;
 721         struct debug_obj *obj;
 722         unsigned long flags;
 723         bool print_object = false;
 724
 725         if (!debug_objects_enabled)
 726                 return;
 727
 728         db = get_bucket((unsigned long) addr);
 729
 730         raw_spin_lock_irqsave(&db->lock, flags);
 731
 732         obj = lookup_object(addr, db);
 733         if (obj) {
 734                 switch (obj->state) {
 735                 case ODEBUG_STATE_INIT:
 736                 case ODEBUG_STATE_INACTIVE:
 737                 case ODEBUG_STATE_ACTIVE:
 738                         if (!obj->astate)
 739                                 obj->state = ODEBUG_STATE_INACTIVE;
 740                         else
 741                                 print_object = true;
 742                         break;
 743
 744                 case ODEBUG_STATE_DESTROYED:
 745                         print_object = true;
 746                         break;
 747                 default:
 748                         break;
 749                 }
 750         }
 751
 752         raw_spin_unlock_irqrestore(&db->lock, flags);
 753         if (!obj) {
 754                 struct debug_obj o = { .object = addr,
 755                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 756                                        .descr = descr };
 757
 758                 debug_print_object(&o, "deactivate");
 759         } else if (print_object) {
 760                 debug_print_object(obj, "deactivate");
 761         }
 762 }
 763 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 764
 765 /**
 766  * debug_object_destroy - debug checks when an object is destroyed
 767  * @addr:       address of the object
 768  * @descr:      pointer to an object specific debug description structure
 769  */
 770 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
 771 {
 772         enum debug_obj_state state;
 773         struct debug_bucket *db;
 774         struct debug_obj *obj;
 775         unsigned long flags;
 776         bool print_object = false;
 777
 778         if (!debug_objects_enabled)
 779                 return;
 780
 781         db = get_bucket((unsigned long) addr);
 782
 783         raw_spin_lock_irqsave(&db->lock, flags);
 784
 785         obj = lookup_object(addr, db);
 786         if (!obj)
 787                 goto out_unlock;
 788
 789         switch (obj->state) {
 790         case ODEBUG_STATE_NONE:
 791         case ODEBUG_STATE_INIT:
 792         case ODEBUG_STATE_INACTIVE:
 793                 obj->state = ODEBUG_STATE_DESTROYED;
 794                 break;
 795         case ODEBUG_STATE_ACTIVE:
 796                 state = obj->state;
 797                 raw_spin_unlock_irqrestore(&db->lock, flags);
 798                 debug_print_object(obj, "destroy");
 799                 debug_object_fixup(descr->fixup_destroy, addr, state);
 800                 return;
 801
 802         case ODEBUG_STATE_DESTROYED:
 803                 print_object = true;
 804                 break;
 805         default:
 806                 break;
 807         }
 808 out_unlock:
 809         raw_spin_unlock_irqrestore(&db->lock, flags);
 810         if (print_object)
 811                 debug_print_object(obj, "destroy");
 812 }
 813 EXPORT_SYMBOL_GPL(debug_object_destroy);
 814
 815 /**
 816  * debug_object_free - debug checks when an object is freed
 817  * @addr:       address of the object
 818  * @descr:      pointer to an object specific debug description structure
 819  */
 820 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
 821 {
 822         enum debug_obj_state state;
 823         struct debug_bucket *db;
 824         struct debug_obj *obj;
 825         unsigned long flags;
 826
 827         if (!debug_objects_enabled)
 828                 return;
 829
 830         db = get_bucket((unsigned long) addr);
 831
 832         raw_spin_lock_irqsave(&db->lock, flags);
 833
 834         obj = lookup_object(addr, db);
 835         if (!obj)
 836                 goto out_unlock;
 837
 838         switch (obj->state) {
 839         case ODEBUG_STATE_ACTIVE:
 840                 state = obj->state;
 841                 raw_spin_unlock_irqrestore(&db->lock, flags);
 842                 debug_print_object(obj, "free");
 843                 debug_object_fixup(descr->fixup_free, addr, state);
 844                 return;
 845         default:
 846                 hlist_del(&obj->node);
 847                 raw_spin_unlock_irqrestore(&db->lock, flags);
 848                 free_object(obj);
 849                 return;
 850         }
 851 out_unlock:
 852         raw_spin_unlock_irqrestore(&db->lock, flags);
 853 }
 854 EXPORT_SYMBOL_GPL(debug_object_free);
 855
 856 /**
 857  * debug_object_assert_init - debug checks when object should be init-ed
 858  * @addr:       address of the object
 859  * @descr:      pointer to an object specific debug description structure
 860  */
 861 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
 862 {
 863         struct debug_bucket *db;
 864         struct debug_obj *obj;
 865         unsigned long flags;
 866
 867         if (!debug_objects_enabled)
 868                 return;
 869
 870         db = get_bucket((unsigned long) addr);
 871
 872         raw_spin_lock_irqsave(&db->lock, flags);
 873
 874         obj = lookup_object(addr, db);
 875         if (!obj) {
 876                 struct debug_obj o = { .object = addr,
 877                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 878                                        .descr = descr };
 879
 880                 raw_spin_unlock_irqrestore(&db->lock, flags);
 881                 /*
 882                  * Maybe the object is static, and we let the type specific
 883                  * code confirm. Track this static object if true, else invoke
 884                  * fixup.
 885                  */
 886                 if (descr->is_static_object && descr->is_static_object(addr)) {
 887                         /* Track this static object */
 888                         debug_object_init(addr, descr);
 889                 } else {
 890                         debug_print_object(&o, "assert_init");
 891                         debug_object_fixup(descr->fixup_assert_init, addr,
 892                                            ODEBUG_STATE_NOTAVAILABLE);
 893                 }
 894                 return;
 895         }
 896
 897         raw_spin_unlock_irqrestore(&db->lock, flags);
 898 }
 899 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 900
 901 /**
 902  * debug_object_active_state - debug checks object usage state machine
 903  * @addr:       address of the object
 904  * @descr:      pointer to an object specific debug description structure
 905  * @expect:     expected state
 906  * @next:       state to move to if expected state is found
 907  */
 908 void
 909 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
 910                           unsigned int expect, unsigned int next)
 911 {
 912         struct debug_bucket *db;
 913         struct debug_obj *obj;
 914         unsigned long flags;
 915         bool print_object = false;
 916
 917         if (!debug_objects_enabled)
 918                 return;
 919
 920         db = get_bucket((unsigned long) addr);
 921
 922         raw_spin_lock_irqsave(&db->lock, flags);
 923
 924         obj = lookup_object(addr, db);
 925         if (obj) {
 926                 switch (obj->state) {
 927                 case ODEBUG_STATE_ACTIVE:
 928                         if (obj->astate == expect)
 929                                 obj->astate = next;
 930                         else
 931                                 print_object = true;
 932                         break;
 933
 934                 default:
 935                         print_object = true;
 936                         break;
 937                 }
 938         }
 939
 940         raw_spin_unlock_irqrestore(&db->lock, flags);
 941         if (!obj) {
 942                 struct debug_obj o = { .object = addr,
 943                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 944                                        .descr = descr };
 945
 946                 debug_print_object(&o, "active_state");
 947         } else if (print_object) {
 948                 debug_print_object(obj, "active_state");
 949         }
 950 }
 951 EXPORT_SYMBOL_GPL(debug_object_active_state);
 952
 953 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 954 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 955 {
 956         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 957         const struct debug_obj_descr *descr;
 958         enum debug_obj_state state;
 959         struct debug_bucket *db;
 960         struct hlist_node *tmp;
 961         struct debug_obj *obj;
 962         int cnt, objs_checked = 0;
 963
 964         saddr = (unsigned long) address;
 965         eaddr = saddr + size;
 966         paddr = saddr & ODEBUG_CHUNK_MASK;
 967         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 968         chunks >>= ODEBUG_CHUNK_SHIFT;
 969
 970         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 971                 db = get_bucket(paddr);
 972
 973 repeat:
 974                 cnt = 0;
 975                 raw_spin_lock_irqsave(&db->lock, flags);
 976                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 977                         cnt++;
 978                         oaddr = (unsigned long) obj->object;
 979                         if (oaddr < saddr || oaddr >= eaddr)
 980                                 continue;
 981
 982                         switch (obj->state) {
 983                         case ODEBUG_STATE_ACTIVE:
 984                                 descr = obj->descr;
 985                                 state = obj->state;
 986                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 987                                 debug_print_object(obj, "free");
 988                                 debug_object_fixup(descr->fixup_free,
 989                                                    (void *) oaddr, state);
 990                                 goto repeat;
 991                         default:
 992                                 hlist_del(&obj->node);
 993                                 __free_object(obj);
 994                                 break;
 995                         }
 996                 }
 997                 raw_spin_unlock_irqrestore(&db->lock, flags);
 998
 999                 if (cnt > debug_objects_maxchain)
1000                         debug_objects_maxchain = cnt;
1001
1002                 objs_checked += cnt;
1003         }
1004
1005         if (objs_checked > debug_objects_maxchecked)
1006                 debug_objects_maxchecked = objs_checked;
1007
1008         /* Schedule work to actually kmem_cache_free() objects */
1009         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1010                 WRITE_ONCE(obj_freeing, true);
1011                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1012         }
1013 }
1014
1015 void debug_check_no_obj_freed(const void *address, unsigned long size)
1016 {
1017         if (debug_objects_enabled)
1018                 __debug_check_no_obj_freed(address, size);
1019 }
1020 #endif
1021
1022 #ifdef CONFIG_DEBUG_FS
1023
1024 static int debug_stats_show(struct seq_file *m, void *v)
1025 {
1026         int cpu, obj_percpu_free = 0;
1027
1028         for_each_possible_cpu(cpu)
1029                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1030
1031         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1032         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1033         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1034         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1035         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1036         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1037         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1038         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1039         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1040         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1041         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1042         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1043         return 0;
1044 }
1045 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1046
1047 static int __init debug_objects_init_debugfs(void)
1048 {
1049         struct dentry *dbgdir;
1050
1051         if (!debug_objects_enabled)
1052                 return 0;
1053
1054         dbgdir = debugfs_create_dir("debug_objects", NULL);
1055
1056         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1057
1058         return 0;
1059 }
1060 __initcall(debug_objects_init_debugfs);
1061
1062 #else
1063 static inline void debug_objects_init_debugfs(void) { }
1064 #endif
1065
1066 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1067
1068 /* Random data structure for the self test */
1069 struct self_test {
1070         unsigned long   dummy1[6];
1071         int             static_init;
1072         unsigned long   dummy2[3];
1073 };
1074
1075 static __initconst const struct debug_obj_descr descr_type_test;
1076
1077 static bool __init is_static_object(void *addr)
1078 {
1079         struct self_test *obj = addr;
1080
1081         return obj->static_init;
1082 }
1083
1084 /*
1085  * fixup_init is called when:
1086  * - an active object is initialized
1087  */
1088 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1089 {
1090         struct self_test *obj = addr;
1091
1092         switch (state) {
1093         case ODEBUG_STATE_ACTIVE:
1094                 debug_object_deactivate(obj, &descr_type_test);
1095                 debug_object_init(obj, &descr_type_test);
1096                 return true;
1097         default:
1098                 return false;
1099         }
1100 }
1101
1102 /*
1103  * fixup_activate is called when:
1104  * - an active object is activated
1105  * - an unknown non-static object is activated
1106  */
1107 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1108 {
1109         struct self_test *obj = addr;
1110
1111         switch (state) {
1112         case ODEBUG_STATE_NOTAVAILABLE:
1113                 return true;
1114         case ODEBUG_STATE_ACTIVE:
1115                 debug_object_deactivate(obj, &descr_type_test);
1116                 debug_object_activate(obj, &descr_type_test);
1117                 return true;
1118
1119         default:
1120                 return false;
1121         }
1122 }
1123
1124 /*
1125  * fixup_destroy is called when:
1126  * - an active object is destroyed
1127  */
1128 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1129 {
1130         struct self_test *obj = addr;
1131
1132         switch (state) {
1133         case ODEBUG_STATE_ACTIVE:
1134                 debug_object_deactivate(obj, &descr_type_test);
1135                 debug_object_destroy(obj, &descr_type_test);
1136                 return true;
1137         default:
1138                 return false;
1139         }
1140 }
1141
1142 /*
1143  * fixup_free is called when:
1144  * - an active object is freed
1145  */
1146 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1147 {
1148         struct self_test *obj = addr;
1149
1150         switch (state) {
1151         case ODEBUG_STATE_ACTIVE:
1152                 debug_object_deactivate(obj, &descr_type_test);
1153                 debug_object_free(obj, &descr_type_test);
1154                 return true;
1155         default:
1156                 return false;
1157         }
1158 }
1159
1160 static int __init
1161 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1162 {
1163         struct debug_bucket *db;
1164         struct debug_obj *obj;
1165         unsigned long flags;
1166         int res = -EINVAL;
1167
1168         db = get_bucket((unsigned long) addr);
1169
1170         raw_spin_lock_irqsave(&db->lock, flags);
1171
1172         obj = lookup_object(addr, db);
1173         if (!obj && state != ODEBUG_STATE_NONE) {
1174                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1175                 goto out;
1176         }
1177         if (obj && obj->state != state) {
1178                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1179                        obj->state, state);
1180                 goto out;
1181         }
1182         if (fixups != debug_objects_fixups) {
1183                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1184                        fixups, debug_objects_fixups);
1185                 goto out;
1186         }
1187         if (warnings != debug_objects_warnings) {
1188                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1189                        warnings, debug_objects_warnings);
1190                 goto out;
1191         }
1192         res = 0;
1193 out:
1194         raw_spin_unlock_irqrestore(&db->lock, flags);
1195         if (res)
1196                 debug_objects_enabled = 0;
1197         return res;
1198 }
1199
1200 static __initconst const struct debug_obj_descr descr_type_test = {
1201         .name                   = "selftest",
1202         .is_static_object       = is_static_object,
1203         .fixup_init             = fixup_init,
1204         .fixup_activate         = fixup_activate,
1205         .fixup_destroy          = fixup_destroy,
1206         .fixup_free             = fixup_free,
1207 };
1208
1209 static __initdata struct self_test obj = { .static_init = 0 };
1210
1211 static void __init debug_objects_selftest(void)
1212 {
1213         int fixups, oldfixups, warnings, oldwarnings;
1214         unsigned long flags;
1215
1216         local_irq_save(flags);
1217
1218         fixups = oldfixups = debug_objects_fixups;
1219         warnings = oldwarnings = debug_objects_warnings;
1220         descr_test = &descr_type_test;
1221
1222         debug_object_init(&obj, &descr_type_test);
1223         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1224                 goto out;
1225         debug_object_activate(&obj, &descr_type_test);
1226         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1227                 goto out;
1228         debug_object_activate(&obj, &descr_type_test);
1229         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1230                 goto out;
1231         debug_object_deactivate(&obj, &descr_type_test);
1232         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1233                 goto out;
1234         debug_object_destroy(&obj, &descr_type_test);
1235         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1236                 goto out;
1237         debug_object_init(&obj, &descr_type_test);
1238         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1239                 goto out;
1240         debug_object_activate(&obj, &descr_type_test);
1241         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1242                 goto out;
1243         debug_object_deactivate(&obj, &descr_type_test);
1244         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1245                 goto out;
1246         debug_object_free(&obj, &descr_type_test);
1247         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1248                 goto out;
1249
1250         obj.static_init = 1;
1251         debug_object_activate(&obj, &descr_type_test);
1252         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1253                 goto out;
1254         debug_object_init(&obj, &descr_type_test);
1255         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1256                 goto out;
1257         debug_object_free(&obj, &descr_type_test);
1258         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1259                 goto out;
1260
1261 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1262         debug_object_init(&obj, &descr_type_test);
1263         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1264                 goto out;
1265         debug_object_activate(&obj, &descr_type_test);
1266         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1267                 goto out;
1268         __debug_check_no_obj_freed(&obj, sizeof(obj));
1269         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1270                 goto out;
1271 #endif
1272         pr_info("selftest passed\n");
1273
1274 out:
1275         debug_objects_fixups = oldfixups;
1276         debug_objects_warnings = oldwarnings;
1277         descr_test = NULL;
1278
1279         local_irq_restore(flags);
1280 }
1281 #else
1282 static inline void debug_objects_selftest(void) { }
1283 #endif
1284
1285 /*
1286  * Called during early boot to initialize the hash buckets and link
1287  * the static object pool objects into the poll list. After this call
1288  * the object tracker is fully operational.
1289  */
1290 void __init debug_objects_early_init(void)
1291 {
1292         int i;
1293
1294         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1295                 raw_spin_lock_init(&obj_hash[i].lock);
1296
1297         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1298                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1299 }
1300
1301 /*
1302  * Convert the statically allocated objects to dynamic ones:
1303  */
1304 static int __init debug_objects_replace_static_objects(void)
1305 {
1306         struct debug_bucket *db = obj_hash;
1307         struct hlist_node *tmp;
1308         struct debug_obj *obj, *new;
1309         HLIST_HEAD(objects);
1310         int i, cnt = 0;
1311
1312         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1313                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1314                 if (!obj)
1315                         goto free;
1316                 hlist_add_head(&obj->node, &objects);
1317         }
1318
1319         /*
1320          * debug_objects_mem_init() is now called early that only one CPU is up
1321          * and interrupts have been disabled, so it is safe to replace the
1322          * active object references.
1323          */
1324
1325         /* Remove the statically allocated objects from the pool */
1326         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1327                 hlist_del(&obj->node);
1328         /* Move the allocated objects to the pool */
1329         hlist_move_list(&objects, &obj_pool);
1330
1331         /* Replace the active object references */
1332         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1333                 hlist_move_list(&db->list, &objects);
1334
1335                 hlist_for_each_entry(obj, &objects, node) {
1336                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1337                         hlist_del(&new->node);
1338                         /* copy object data */
1339                         *new = *obj;
1340                         hlist_add_head(&new->node, &db->list);
1341                         cnt++;
1342                 }
1343         }
1344
1345         pr_debug("%d of %d active objects replaced\n",
1346                  cnt, obj_pool_used);
1347         return 0;
1348 free:
1349         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1350                 hlist_del(&obj->node);
1351                 kmem_cache_free(obj_cache, obj);
1352         }
1353         return -ENOMEM;
1354 }
1355
1356 /*
1357  * Called after the kmem_caches are functional to setup a dedicated
1358  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1359  * prevents that the debug code is called on kmem_cache_free() for the
1360  * debug tracker objects to avoid recursive calls.
1361  */
1362 void __init debug_objects_mem_init(void)
1363 {
1364         int cpu, extras;
1365
1366         if (!debug_objects_enabled)
1367                 return;
1368
1369         /*
1370          * Initialize the percpu object pools
1371          *
1372          * Initialization is not strictly necessary, but was done for
1373          * completeness.
1374          */
1375         for_each_possible_cpu(cpu)
1376                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1377
1378         obj_cache = kmem_cache_create("debug_objects_cache",
1379                                       sizeof (struct debug_obj), 0,
1380                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1381                                       NULL);
1382
1383         if (!obj_cache || debug_objects_replace_static_objects()) {
1384                 debug_objects_enabled = 0;
1385                 kmem_cache_destroy(obj_cache);
1386                 pr_warn("out of memory.\n");
1387         } else
1388                 debug_objects_selftest();
1389
1390 #ifdef CONFIG_HOTPLUG_CPU
1391         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1392                                         object_cpu_offline);
1393 #endif
1394
1395         /*
1396          * Increase the thresholds for allocating and freeing objects
1397          * according to the number of possible CPUs available in the system.
1398          */
1399         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1400         debug_objects_pool_size += extras;
1401         debug_objects_pool_min_level += extras;
1402 }