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         unsigned long flags;
 444
 445         /* Remote access is safe as the CPU is dead already */
 446         percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
 447         hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
 448                 hlist_del(&obj->node);
 449                 kmem_cache_free(obj_cache, obj);
 450         }
 451
 452         raw_spin_lock_irqsave(&pool_lock, flags);
 453         obj_pool_used -= percpu_pool->obj_free;
 454         debug_objects_freed += percpu_pool->obj_free;
 455         raw_spin_unlock_irqrestore(&pool_lock, flags);
 456
 457         percpu_pool->obj_free = 0;
 458
 459         return 0;
 460 }
 461 #endif
 462
 463 /*
 464  * We run out of memory. That means we probably have tons of objects
 465  * allocated.
 466  */
 467 static void debug_objects_oom(void)
 468 {
 469         struct debug_bucket *db = obj_hash;
 470         struct hlist_node *tmp;
 471         HLIST_HEAD(freelist);
 472         struct debug_obj *obj;
 473         unsigned long flags;
 474         int i;
 475
 476         pr_warn("Out of memory. ODEBUG disabled\n");
 477
 478         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 479                 raw_spin_lock_irqsave(&db->lock, flags);
 480                 hlist_move_list(&db->list, &freelist);
 481                 raw_spin_unlock_irqrestore(&db->lock, flags);
 482
 483                 /* Now free them */
 484                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 485                         hlist_del(&obj->node);
 486                         free_object(obj);
 487                 }
 488         }
 489 }
 490
 491 /*
 492  * We use the pfn of the address for the hash. That way we can check
 493  * for freed objects simply by checking the affected bucket.
 494  */
 495 static struct debug_bucket *get_bucket(unsigned long addr)
 496 {
 497         unsigned long hash;
 498
 499         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 500         return &obj_hash[hash];
 501 }
 502
 503 static void debug_print_object(struct debug_obj *obj, char *msg)
 504 {
 505         const struct debug_obj_descr *descr = obj->descr;
 506         static int limit;
 507
 508         if (limit < 5 && descr != descr_test) {
 509                 void *hint = descr->debug_hint ?
 510                         descr->debug_hint(obj->object) : NULL;
 511                 limit++;
 512                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 513                                  "object type: %s hint: %pS\n",
 514                         msg, obj_states[obj->state], obj->astate,
 515                         descr->name, hint);
 516         }
 517         debug_objects_warnings++;
 518 }
 519
 520 /*
 521  * Try to repair the damage, so we have a better chance to get useful
 522  * debug output.
 523  */
 524 static bool
 525 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 526                    void * addr, enum debug_obj_state state)
 527 {
 528         if (fixup && fixup(addr, state)) {
 529                 debug_objects_fixups++;
 530                 return true;
 531         }
 532         return false;
 533 }
 534
 535 static void debug_object_is_on_stack(void *addr, int onstack)
 536 {
 537         int is_on_stack;
 538         static int limit;
 539
 540         if (limit > 4)
 541                 return;
 542
 543         is_on_stack = object_is_on_stack(addr);
 544         if (is_on_stack == onstack)
 545                 return;
 546
 547         limit++;
 548         if (is_on_stack)
 549                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 550                          task_stack_page(current));
 551         else
 552                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 553                          task_stack_page(current));
 554
 555         WARN_ON(1);
 556 }
 557
 558 static void
 559 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
 560 {
 561         enum debug_obj_state state;
 562         bool check_stack = false;
 563         struct debug_bucket *db;
 564         struct debug_obj *obj;
 565         unsigned long flags;
 566
 567         /*
 568          * On RT enabled kernels the pool refill must happen in preemptible
 569          * context:
 570          */
 571         if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
 572                 fill_pool();
 573
 574         db = get_bucket((unsigned long) addr);
 575
 576         raw_spin_lock_irqsave(&db->lock, flags);
 577
 578         obj = lookup_object(addr, db);
 579         if (!obj) {
 580                 obj = alloc_object(addr, db, descr);
 581                 if (!obj) {
 582                         debug_objects_enabled = 0;
 583                         raw_spin_unlock_irqrestore(&db->lock, flags);
 584                         debug_objects_oom();
 585                         return;
 586                 }
 587                 check_stack = true;
 588         }
 589
 590         switch (obj->state) {
 591         case ODEBUG_STATE_NONE:
 592         case ODEBUG_STATE_INIT:
 593         case ODEBUG_STATE_INACTIVE:
 594                 obj->state = ODEBUG_STATE_INIT;
 595                 break;
 596
 597         case ODEBUG_STATE_ACTIVE:
 598                 state = obj->state;
 599                 raw_spin_unlock_irqrestore(&db->lock, flags);
 600                 debug_print_object(obj, "init");
 601                 debug_object_fixup(descr->fixup_init, addr, state);
 602                 return;
 603
 604         case ODEBUG_STATE_DESTROYED:
 605                 raw_spin_unlock_irqrestore(&db->lock, flags);
 606                 debug_print_object(obj, "init");
 607                 return;
 608         default:
 609                 break;
 610         }
 611
 612         raw_spin_unlock_irqrestore(&db->lock, flags);
 613         if (check_stack)
 614                 debug_object_is_on_stack(addr, onstack);
 615 }
 616
 617 /**
 618  * debug_object_init - debug checks when an object is initialized
 619  * @addr:       address of the object
 620  * @descr:      pointer to an object specific debug description structure
 621  */
 622 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
 623 {
 624         if (!debug_objects_enabled)
 625                 return;
 626
 627         __debug_object_init(addr, descr, 0);
 628 }
 629 EXPORT_SYMBOL_GPL(debug_object_init);
 630
 631 /**
 632  * debug_object_init_on_stack - debug checks when an object on stack is
 633  *                              initialized
 634  * @addr:       address of the object
 635  * @descr:      pointer to an object specific debug description structure
 636  */
 637 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
 638 {
 639         if (!debug_objects_enabled)
 640                 return;
 641
 642         __debug_object_init(addr, descr, 1);
 643 }
 644 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 645
 646 /**
 647  * debug_object_activate - debug checks when an object is activated
 648  * @addr:       address of the object
 649  * @descr:      pointer to an object specific debug description structure
 650  * Returns 0 for success, -EINVAL for check failed.
 651  */
 652 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
 653 {
 654         enum debug_obj_state state;
 655         struct debug_bucket *db;
 656         struct debug_obj *obj;
 657         unsigned long flags;
 658         int ret;
 659         struct debug_obj o = { .object = addr,
 660                                .state = ODEBUG_STATE_NOTAVAILABLE,
 661                                .descr = descr };
 662
 663         if (!debug_objects_enabled)
 664                 return 0;
 665
 666         db = get_bucket((unsigned long) addr);
 667
 668         raw_spin_lock_irqsave(&db->lock, flags);
 669
 670         obj = lookup_object(addr, db);
 671         if (obj) {
 672                 bool print_object = false;
 673
 674                 switch (obj->state) {
 675                 case ODEBUG_STATE_INIT:
 676                 case ODEBUG_STATE_INACTIVE:
 677                         obj->state = ODEBUG_STATE_ACTIVE;
 678                         ret = 0;
 679                         break;
 680
 681                 case ODEBUG_STATE_ACTIVE:
 682                         state = obj->state;
 683                         raw_spin_unlock_irqrestore(&db->lock, flags);
 684                         debug_print_object(obj, "activate");
 685                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 686                         return ret ? 0 : -EINVAL;
 687
 688                 case ODEBUG_STATE_DESTROYED:
 689                         print_object = true;
 690                         ret = -EINVAL;
 691                         break;
 692                 default:
 693                         ret = 0;
 694                         break;
 695                 }
 696                 raw_spin_unlock_irqrestore(&db->lock, flags);
 697                 if (print_object)
 698                         debug_print_object(obj, "activate");
 699                 return ret;
 700         }
 701
 702         raw_spin_unlock_irqrestore(&db->lock, flags);
 703
 704         /*
 705          * We are here when a static object is activated. We
 706          * let the type specific code confirm whether this is
 707          * true or not. if true, we just make sure that the
 708          * static object is tracked in the object tracker. If
 709          * not, this must be a bug, so we try to fix it up.
 710          */
 711         if (descr->is_static_object && descr->is_static_object(addr)) {
 712                 /* track this static object */
 713                 debug_object_init(addr, descr);
 714                 debug_object_activate(addr, descr);
 715         } else {
 716                 debug_print_object(&o, "activate");
 717                 ret = debug_object_fixup(descr->fixup_activate, addr,
 718                                         ODEBUG_STATE_NOTAVAILABLE);
 719                 return ret ? 0 : -EINVAL;
 720         }
 721         return 0;
 722 }
 723 EXPORT_SYMBOL_GPL(debug_object_activate);
 724
 725 /**
 726  * debug_object_deactivate - debug checks when an object is deactivated
 727  * @addr:       address of the object
 728  * @descr:      pointer to an object specific debug description structure
 729  */
 730 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
 731 {
 732         struct debug_bucket *db;
 733         struct debug_obj *obj;
 734         unsigned long flags;
 735         bool print_object = false;
 736
 737         if (!debug_objects_enabled)
 738                 return;
 739
 740         db = get_bucket((unsigned long) addr);
 741
 742         raw_spin_lock_irqsave(&db->lock, flags);
 743
 744         obj = lookup_object(addr, db);
 745         if (obj) {
 746                 switch (obj->state) {
 747                 case ODEBUG_STATE_INIT:
 748                 case ODEBUG_STATE_INACTIVE:
 749                 case ODEBUG_STATE_ACTIVE:
 750                         if (!obj->astate)
 751                                 obj->state = ODEBUG_STATE_INACTIVE;
 752                         else
 753                                 print_object = true;
 754                         break;
 755
 756                 case ODEBUG_STATE_DESTROYED:
 757                         print_object = true;
 758                         break;
 759                 default:
 760                         break;
 761                 }
 762         }
 763
 764         raw_spin_unlock_irqrestore(&db->lock, flags);
 765         if (!obj) {
 766                 struct debug_obj o = { .object = addr,
 767                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 768                                        .descr = descr };
 769
 770                 debug_print_object(&o, "deactivate");
 771         } else if (print_object) {
 772                 debug_print_object(obj, "deactivate");
 773         }
 774 }
 775 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 776
 777 /**
 778  * debug_object_destroy - debug checks when an object is destroyed
 779  * @addr:       address of the object
 780  * @descr:      pointer to an object specific debug description structure
 781  */
 782 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
 783 {
 784         enum debug_obj_state state;
 785         struct debug_bucket *db;
 786         struct debug_obj *obj;
 787         unsigned long flags;
 788         bool print_object = false;
 789
 790         if (!debug_objects_enabled)
 791                 return;
 792
 793         db = get_bucket((unsigned long) addr);
 794
 795         raw_spin_lock_irqsave(&db->lock, flags);
 796
 797         obj = lookup_object(addr, db);
 798         if (!obj)
 799                 goto out_unlock;
 800
 801         switch (obj->state) {
 802         case ODEBUG_STATE_NONE:
 803         case ODEBUG_STATE_INIT:
 804         case ODEBUG_STATE_INACTIVE:
 805                 obj->state = ODEBUG_STATE_DESTROYED;
 806                 break;
 807         case ODEBUG_STATE_ACTIVE:
 808                 state = obj->state;
 809                 raw_spin_unlock_irqrestore(&db->lock, flags);
 810                 debug_print_object(obj, "destroy");
 811                 debug_object_fixup(descr->fixup_destroy, addr, state);
 812                 return;
 813
 814         case ODEBUG_STATE_DESTROYED:
 815                 print_object = true;
 816                 break;
 817         default:
 818                 break;
 819         }
 820 out_unlock:
 821         raw_spin_unlock_irqrestore(&db->lock, flags);
 822         if (print_object)
 823                 debug_print_object(obj, "destroy");
 824 }
 825 EXPORT_SYMBOL_GPL(debug_object_destroy);
 826
 827 /**
 828  * debug_object_free - debug checks when an object is freed
 829  * @addr:       address of the object
 830  * @descr:      pointer to an object specific debug description structure
 831  */
 832 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
 833 {
 834         enum debug_obj_state state;
 835         struct debug_bucket *db;
 836         struct debug_obj *obj;
 837         unsigned long flags;
 838
 839         if (!debug_objects_enabled)
 840                 return;
 841
 842         db = get_bucket((unsigned long) addr);
 843
 844         raw_spin_lock_irqsave(&db->lock, flags);
 845
 846         obj = lookup_object(addr, db);
 847         if (!obj)
 848                 goto out_unlock;
 849
 850         switch (obj->state) {
 851         case ODEBUG_STATE_ACTIVE:
 852                 state = obj->state;
 853                 raw_spin_unlock_irqrestore(&db->lock, flags);
 854                 debug_print_object(obj, "free");
 855                 debug_object_fixup(descr->fixup_free, addr, state);
 856                 return;
 857         default:
 858                 hlist_del(&obj->node);
 859                 raw_spin_unlock_irqrestore(&db->lock, flags);
 860                 free_object(obj);
 861                 return;
 862         }
 863 out_unlock:
 864         raw_spin_unlock_irqrestore(&db->lock, flags);
 865 }
 866 EXPORT_SYMBOL_GPL(debug_object_free);
 867
 868 /**
 869  * debug_object_assert_init - debug checks when object should be init-ed
 870  * @addr:       address of the object
 871  * @descr:      pointer to an object specific debug description structure
 872  */
 873 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
 874 {
 875         struct debug_bucket *db;
 876         struct debug_obj *obj;
 877         unsigned long flags;
 878
 879         if (!debug_objects_enabled)
 880                 return;
 881
 882         db = get_bucket((unsigned long) addr);
 883
 884         raw_spin_lock_irqsave(&db->lock, flags);
 885
 886         obj = lookup_object(addr, db);
 887         if (!obj) {
 888                 struct debug_obj o = { .object = addr,
 889                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 890                                        .descr = descr };
 891
 892                 raw_spin_unlock_irqrestore(&db->lock, flags);
 893                 /*
 894                  * Maybe the object is static, and we let the type specific
 895                  * code confirm. Track this static object if true, else invoke
 896                  * fixup.
 897                  */
 898                 if (descr->is_static_object && descr->is_static_object(addr)) {
 899                         /* Track this static object */
 900                         debug_object_init(addr, descr);
 901                 } else {
 902                         debug_print_object(&o, "assert_init");
 903                         debug_object_fixup(descr->fixup_assert_init, addr,
 904                                            ODEBUG_STATE_NOTAVAILABLE);
 905                 }
 906                 return;
 907         }
 908
 909         raw_spin_unlock_irqrestore(&db->lock, flags);
 910 }
 911 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 912
 913 /**
 914  * debug_object_active_state - debug checks object usage state machine
 915  * @addr:       address of the object
 916  * @descr:      pointer to an object specific debug description structure
 917  * @expect:     expected state
 918  * @next:       state to move to if expected state is found
 919  */
 920 void
 921 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
 922                           unsigned int expect, unsigned int next)
 923 {
 924         struct debug_bucket *db;
 925         struct debug_obj *obj;
 926         unsigned long flags;
 927         bool print_object = false;
 928
 929         if (!debug_objects_enabled)
 930                 return;
 931
 932         db = get_bucket((unsigned long) addr);
 933
 934         raw_spin_lock_irqsave(&db->lock, flags);
 935
 936         obj = lookup_object(addr, db);
 937         if (obj) {
 938                 switch (obj->state) {
 939                 case ODEBUG_STATE_ACTIVE:
 940                         if (obj->astate == expect)
 941                                 obj->astate = next;
 942                         else
 943                                 print_object = true;
 944                         break;
 945
 946                 default:
 947                         print_object = true;
 948                         break;
 949                 }
 950         }
 951
 952         raw_spin_unlock_irqrestore(&db->lock, flags);
 953         if (!obj) {
 954                 struct debug_obj o = { .object = addr,
 955                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 956                                        .descr = descr };
 957
 958                 debug_print_object(&o, "active_state");
 959         } else if (print_object) {
 960                 debug_print_object(obj, "active_state");
 961         }
 962 }
 963 EXPORT_SYMBOL_GPL(debug_object_active_state);
 964
 965 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 966 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 967 {
 968         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 969         const struct debug_obj_descr *descr;
 970         enum debug_obj_state state;
 971         struct debug_bucket *db;
 972         struct hlist_node *tmp;
 973         struct debug_obj *obj;
 974         int cnt, objs_checked = 0;
 975
 976         saddr = (unsigned long) address;
 977         eaddr = saddr + size;
 978         paddr = saddr & ODEBUG_CHUNK_MASK;
 979         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 980         chunks >>= ODEBUG_CHUNK_SHIFT;
 981
 982         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 983                 db = get_bucket(paddr);
 984
 985 repeat:
 986                 cnt = 0;
 987                 raw_spin_lock_irqsave(&db->lock, flags);
 988                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 989                         cnt++;
 990                         oaddr = (unsigned long) obj->object;
 991                         if (oaddr < saddr || oaddr >= eaddr)
 992                                 continue;
 993
 994                         switch (obj->state) {
 995                         case ODEBUG_STATE_ACTIVE:
 996                                 descr = obj->descr;
 997                                 state = obj->state;
 998                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 999                                 debug_print_object(obj, "free");
1000                                 debug_object_fixup(descr->fixup_free,
1001                                                    (void *) oaddr, state);
1002                                 goto repeat;
1003                         default:
1004                                 hlist_del(&obj->node);
1005                                 __free_object(obj);
1006                                 break;
1007                         }
1008                 }
1009                 raw_spin_unlock_irqrestore(&db->lock, flags);
1010
1011                 if (cnt > debug_objects_maxchain)
1012                         debug_objects_maxchain = cnt;
1013
1014                 objs_checked += cnt;
1015         }
1016
1017         if (objs_checked > debug_objects_maxchecked)
1018                 debug_objects_maxchecked = objs_checked;
1019
1020         /* Schedule work to actually kmem_cache_free() objects */
1021         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1022                 WRITE_ONCE(obj_freeing, true);
1023                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1024         }
1025 }
1026
1027 void debug_check_no_obj_freed(const void *address, unsigned long size)
1028 {
1029         if (debug_objects_enabled)
1030                 __debug_check_no_obj_freed(address, size);
1031 }
1032 #endif
1033
1034 #ifdef CONFIG_DEBUG_FS
1035
1036 static int debug_stats_show(struct seq_file *m, void *v)
1037 {
1038         int cpu, obj_percpu_free = 0;
1039
1040         for_each_possible_cpu(cpu)
1041                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1042
1043         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1044         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1045         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1046         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1047         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1048         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1049         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1050         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1051         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1052         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1053         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1054         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1055         return 0;
1056 }
1057 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1058
1059 static int __init debug_objects_init_debugfs(void)
1060 {
1061         struct dentry *dbgdir;
1062
1063         if (!debug_objects_enabled)
1064                 return 0;
1065
1066         dbgdir = debugfs_create_dir("debug_objects", NULL);
1067
1068         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1069
1070         return 0;
1071 }
1072 __initcall(debug_objects_init_debugfs);
1073
1074 #else
1075 static inline void debug_objects_init_debugfs(void) { }
1076 #endif
1077
1078 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1079
1080 /* Random data structure for the self test */
1081 struct self_test {
1082         unsigned long   dummy1[6];
1083         int             static_init;
1084         unsigned long   dummy2[3];
1085 };
1086
1087 static __initconst const struct debug_obj_descr descr_type_test;
1088
1089 static bool __init is_static_object(void *addr)
1090 {
1091         struct self_test *obj = addr;
1092
1093         return obj->static_init;
1094 }
1095
1096 /*
1097  * fixup_init is called when:
1098  * - an active object is initialized
1099  */
1100 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1101 {
1102         struct self_test *obj = addr;
1103
1104         switch (state) {
1105         case ODEBUG_STATE_ACTIVE:
1106                 debug_object_deactivate(obj, &descr_type_test);
1107                 debug_object_init(obj, &descr_type_test);
1108                 return true;
1109         default:
1110                 return false;
1111         }
1112 }
1113
1114 /*
1115  * fixup_activate is called when:
1116  * - an active object is activated
1117  * - an unknown non-static object is activated
1118  */
1119 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1120 {
1121         struct self_test *obj = addr;
1122
1123         switch (state) {
1124         case ODEBUG_STATE_NOTAVAILABLE:
1125                 return true;
1126         case ODEBUG_STATE_ACTIVE:
1127                 debug_object_deactivate(obj, &descr_type_test);
1128                 debug_object_activate(obj, &descr_type_test);
1129                 return true;
1130
1131         default:
1132                 return false;
1133         }
1134 }
1135
1136 /*
1137  * fixup_destroy is called when:
1138  * - an active object is destroyed
1139  */
1140 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1141 {
1142         struct self_test *obj = addr;
1143
1144         switch (state) {
1145         case ODEBUG_STATE_ACTIVE:
1146                 debug_object_deactivate(obj, &descr_type_test);
1147                 debug_object_destroy(obj, &descr_type_test);
1148                 return true;
1149         default:
1150                 return false;
1151         }
1152 }
1153
1154 /*
1155  * fixup_free is called when:
1156  * - an active object is freed
1157  */
1158 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1159 {
1160         struct self_test *obj = addr;
1161
1162         switch (state) {
1163         case ODEBUG_STATE_ACTIVE:
1164                 debug_object_deactivate(obj, &descr_type_test);
1165                 debug_object_free(obj, &descr_type_test);
1166                 return true;
1167         default:
1168                 return false;
1169         }
1170 }
1171
1172 static int __init
1173 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1174 {
1175         struct debug_bucket *db;
1176         struct debug_obj *obj;
1177         unsigned long flags;
1178         int res = -EINVAL;
1179
1180         db = get_bucket((unsigned long) addr);
1181
1182         raw_spin_lock_irqsave(&db->lock, flags);
1183
1184         obj = lookup_object(addr, db);
1185         if (!obj && state != ODEBUG_STATE_NONE) {
1186                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1187                 goto out;
1188         }
1189         if (obj && obj->state != state) {
1190                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1191                        obj->state, state);
1192                 goto out;
1193         }
1194         if (fixups != debug_objects_fixups) {
1195                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1196                        fixups, debug_objects_fixups);
1197                 goto out;
1198         }
1199         if (warnings != debug_objects_warnings) {
1200                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1201                        warnings, debug_objects_warnings);
1202                 goto out;
1203         }
1204         res = 0;
1205 out:
1206         raw_spin_unlock_irqrestore(&db->lock, flags);
1207         if (res)
1208                 debug_objects_enabled = 0;
1209         return res;
1210 }
1211
1212 static __initconst const struct debug_obj_descr descr_type_test = {
1213         .name                   = "selftest",
1214         .is_static_object       = is_static_object,
1215         .fixup_init             = fixup_init,
1216         .fixup_activate         = fixup_activate,
1217         .fixup_destroy          = fixup_destroy,
1218         .fixup_free             = fixup_free,
1219 };
1220
1221 static __initdata struct self_test obj = { .static_init = 0 };
1222
1223 static void __init debug_objects_selftest(void)
1224 {
1225         int fixups, oldfixups, warnings, oldwarnings;
1226         unsigned long flags;
1227
1228         local_irq_save(flags);
1229
1230         fixups = oldfixups = debug_objects_fixups;
1231         warnings = oldwarnings = debug_objects_warnings;
1232         descr_test = &descr_type_test;
1233
1234         debug_object_init(&obj, &descr_type_test);
1235         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1236                 goto out;
1237         debug_object_activate(&obj, &descr_type_test);
1238         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1239                 goto out;
1240         debug_object_activate(&obj, &descr_type_test);
1241         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1242                 goto out;
1243         debug_object_deactivate(&obj, &descr_type_test);
1244         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1245                 goto out;
1246         debug_object_destroy(&obj, &descr_type_test);
1247         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1248                 goto out;
1249         debug_object_init(&obj, &descr_type_test);
1250         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1251                 goto out;
1252         debug_object_activate(&obj, &descr_type_test);
1253         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1254                 goto out;
1255         debug_object_deactivate(&obj, &descr_type_test);
1256         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1257                 goto out;
1258         debug_object_free(&obj, &descr_type_test);
1259         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1260                 goto out;
1261
1262         obj.static_init = 1;
1263         debug_object_activate(&obj, &descr_type_test);
1264         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1265                 goto out;
1266         debug_object_init(&obj, &descr_type_test);
1267         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1268                 goto out;
1269         debug_object_free(&obj, &descr_type_test);
1270         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1271                 goto out;
1272
1273 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1274         debug_object_init(&obj, &descr_type_test);
1275         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1276                 goto out;
1277         debug_object_activate(&obj, &descr_type_test);
1278         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1279                 goto out;
1280         __debug_check_no_obj_freed(&obj, sizeof(obj));
1281         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1282                 goto out;
1283 #endif
1284         pr_info("selftest passed\n");
1285
1286 out:
1287         debug_objects_fixups = oldfixups;
1288         debug_objects_warnings = oldwarnings;
1289         descr_test = NULL;
1290
1291         local_irq_restore(flags);
1292 }
1293 #else
1294 static inline void debug_objects_selftest(void) { }
1295 #endif
1296
1297 /*
1298  * Called during early boot to initialize the hash buckets and link
1299  * the static object pool objects into the poll list. After this call
1300  * the object tracker is fully operational.
1301  */
1302 void __init debug_objects_early_init(void)
1303 {
1304         int i;
1305
1306         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1307                 raw_spin_lock_init(&obj_hash[i].lock);
1308
1309         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1310                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1311 }
1312
1313 /*
1314  * Convert the statically allocated objects to dynamic ones:
1315  */
1316 static int __init debug_objects_replace_static_objects(void)
1317 {
1318         struct debug_bucket *db = obj_hash;
1319         struct hlist_node *tmp;
1320         struct debug_obj *obj, *new;
1321         HLIST_HEAD(objects);
1322         int i, cnt = 0;
1323
1324         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1325                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1326                 if (!obj)
1327                         goto free;
1328                 hlist_add_head(&obj->node, &objects);
1329         }
1330
1331         debug_objects_allocated += i;
1332
1333         /*
1334          * debug_objects_mem_init() is now called early that only one CPU is up
1335          * and interrupts have been disabled, so it is safe to replace the
1336          * active object references.
1337          */
1338
1339         /* Remove the statically allocated objects from the pool */
1340         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1341                 hlist_del(&obj->node);
1342         /* Move the allocated objects to the pool */
1343         hlist_move_list(&objects, &obj_pool);
1344
1345         /* Replace the active object references */
1346         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1347                 hlist_move_list(&db->list, &objects);
1348
1349                 hlist_for_each_entry(obj, &objects, node) {
1350                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1351                         hlist_del(&new->node);
1352                         /* copy object data */
1353                         *new = *obj;
1354                         hlist_add_head(&new->node, &db->list);
1355                         cnt++;
1356                 }
1357         }
1358
1359         pr_debug("%d of %d active objects replaced\n",
1360                  cnt, obj_pool_used);
1361         return 0;
1362 free:
1363         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1364                 hlist_del(&obj->node);
1365                 kmem_cache_free(obj_cache, obj);
1366         }
1367         return -ENOMEM;
1368 }
1369
1370 /*
1371  * Called after the kmem_caches are functional to setup a dedicated
1372  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1373  * prevents that the debug code is called on kmem_cache_free() for the
1374  * debug tracker objects to avoid recursive calls.
1375  */
1376 void __init debug_objects_mem_init(void)
1377 {
1378         int cpu, extras;
1379
1380         if (!debug_objects_enabled)
1381                 return;
1382
1383         /*
1384          * Initialize the percpu object pools
1385          *
1386          * Initialization is not strictly necessary, but was done for
1387          * completeness.
1388          */
1389         for_each_possible_cpu(cpu)
1390                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1391
1392         obj_cache = kmem_cache_create("debug_objects_cache",
1393                                       sizeof (struct debug_obj), 0,
1394                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1395                                       NULL);
1396
1397         if (!obj_cache || debug_objects_replace_static_objects()) {
1398                 debug_objects_enabled = 0;
1399                 kmem_cache_destroy(obj_cache);
1400                 pr_warn("out of memory.\n");
1401                 return;
1402         } else
1403                 debug_objects_selftest();
1404
1405 #ifdef CONFIG_HOTPLUG_CPU
1406         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1407                                         object_cpu_offline);
1408 #endif
1409
1410         /*
1411          * Increase the thresholds for allocating and freeing objects
1412          * according to the number of possible CPUs available in the system.
1413          */
1414         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1415         debug_objects_pool_size += extras;
1416         debug_objects_pool_min_level += extras;
1417 }