lib/debugobjects.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Generic infrastructure for lifetime debugging of objects.
   4  *
   5  * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
   6  */
   7
   8 #define pr_fmt(fmt) "ODEBUG: " fmt
   9
  10 #include <linux/debugobjects.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/sched.h>
  13 #include <linux/sched/task_stack.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/debugfs.h>
  16 #include <linux/slab.h>
  17 #include <linux/hash.h>
  18 #include <linux/kmemleak.h>
  19 #include <linux/cpu.h>
  20
  21 #define ODEBUG_HASH_BITS        14
  22 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  23
  24 #define ODEBUG_POOL_SIZE        1024
  25 #define ODEBUG_POOL_MIN_LEVEL   256
  26 #define ODEBUG_POOL_PERCPU_SIZE 64
  27 #define ODEBUG_BATCH_SIZE       16
  28
  29 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  30 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  31 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  32
  33 /*
  34  * We limit the freeing of debug objects via workqueue at a maximum
  35  * frequency of 10Hz and about 1024 objects for each freeing operation.
  36  * So it is freeing at most 10k debug objects per second.
  37  */
  38 #define ODEBUG_FREE_WORK_MAX    1024
  39 #define ODEBUG_FREE_WORK_DELAY  DIV_ROUND_UP(HZ, 10)
  40
  41 struct debug_bucket {
  42         struct hlist_head       list;
  43         raw_spinlock_t          lock;
  44 };
  45
  46 /*
  47  * Debug object percpu free list
  48  * Access is protected by disabling irq
  49  */
  50 struct debug_percpu_free {
  51         struct hlist_head       free_objs;
  52         int                     obj_free;
  53 };
  54
  55 static DEFINE_PER_CPU(struct debug_percpu_free, percpu_obj_pool);
  56
  57 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  58
  59 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  60
  61 static DEFINE_RAW_SPINLOCK(pool_lock);
  62
  63 static HLIST_HEAD(obj_pool);
  64 static HLIST_HEAD(obj_to_free);
  65
  66 /*
  67  * Because of the presence of percpu free pools, obj_pool_free will
  68  * under-count those in the percpu free pools. Similarly, obj_pool_used
  69  * will over-count those in the percpu free pools. Adjustments will be
  70  * made at debug_stats_show(). Both obj_pool_min_free and obj_pool_max_used
  71  * can be off.
  72  */
  73 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  74 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  75 static int                      obj_pool_used;
  76 static int                      obj_pool_max_used;
  77 static bool                     obj_freeing;
  78 /* The number of objs on the global free list */
  79 static int                      obj_nr_tofree;
  80
  81 static int                      debug_objects_maxchain __read_mostly;
  82 static int __maybe_unused       debug_objects_maxchecked __read_mostly;
  83 static int                      debug_objects_fixups __read_mostly;
  84 static int                      debug_objects_warnings __read_mostly;
  85 static int                      debug_objects_enabled __read_mostly
  86                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  87 static int                      debug_objects_pool_size __read_mostly
  88                                 = ODEBUG_POOL_SIZE;
  89 static int                      debug_objects_pool_min_level __read_mostly
  90                                 = ODEBUG_POOL_MIN_LEVEL;
  91 static const struct debug_obj_descr *descr_test  __read_mostly;
  92 static struct kmem_cache        *obj_cache __read_mostly;
  93
  94 /*
  95  * Track numbers of kmem_cache_alloc()/free() calls done.
  96  */
  97 static int                      debug_objects_allocated;
  98 static int                      debug_objects_freed;
  99
 100 static void free_obj_work(struct work_struct *work);
 101 static DECLARE_DELAYED_WORK(debug_obj_work, free_obj_work);
 102
 103 static int __init enable_object_debug(char *str)
 104 {
 105         debug_objects_enabled = 1;
 106         return 0;
 107 }
 108
 109 static int __init disable_object_debug(char *str)
 110 {
 111         debug_objects_enabled = 0;
 112         return 0;
 113 }
 114
 115 early_param("debug_objects", enable_object_debug);
 116 early_param("no_debug_objects", disable_object_debug);
 117
 118 static const char *obj_states[ODEBUG_STATE_MAX] = {
 119         [ODEBUG_STATE_NONE]             = "none",
 120         [ODEBUG_STATE_INIT]             = "initialized",
 121         [ODEBUG_STATE_INACTIVE]         = "inactive",
 122         [ODEBUG_STATE_ACTIVE]           = "active",
 123         [ODEBUG_STATE_DESTROYED]        = "destroyed",
 124         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
 125 };
 126
 127 static void fill_pool(void)
 128 {
 129         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
 130         struct debug_obj *obj;
 131         unsigned long flags;
 132
 133         if (likely(READ_ONCE(obj_pool_free) >= debug_objects_pool_min_level))
 134                 return;
 135
 136         /*
 137          * Reuse objs from the global free list; they will be reinitialized
 138          * when allocating.
 139          *
 140          * Both obj_nr_tofree and obj_pool_free are checked locklessly; the
 141          * READ_ONCE()s pair with the WRITE_ONCE()s in pool_lock critical
 142          * sections.
 143          */
 144         while (READ_ONCE(obj_nr_tofree) && (READ_ONCE(obj_pool_free) < obj_pool_min_free)) {
 145                 raw_spin_lock_irqsave(&pool_lock, flags);
 146                 /*
 147                  * Recheck with the lock held as the worker thread might have
 148                  * won the race and freed the global free list already.
 149                  */
 150                 while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 151                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 152                         hlist_del(&obj->node);
 153                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 154                         hlist_add_head(&obj->node, &obj_pool);
 155                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 156                 }
 157                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 158         }
 159
 160         if (unlikely(!obj_cache))
 161                 return;
 162
 163         while (READ_ONCE(obj_pool_free) < debug_objects_pool_min_level) {
 164                 struct debug_obj *new[ODEBUG_BATCH_SIZE];
 165                 int cnt;
 166
 167                 for (cnt = 0; cnt < ODEBUG_BATCH_SIZE; cnt++) {
 168                         new[cnt] = kmem_cache_zalloc(obj_cache, gfp);
 169                         if (!new[cnt])
 170                                 break;
 171                 }
 172                 if (!cnt)
 173                         return;
 174
 175                 raw_spin_lock_irqsave(&pool_lock, flags);
 176                 while (cnt) {
 177                         hlist_add_head(&new[--cnt]->node, &obj_pool);
 178                         debug_objects_allocated++;
 179                         WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 180                 }
 181                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 182         }
 183 }
 184
 185 /*
 186  * Lookup an object in the hash bucket.
 187  */
 188 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 189 {
 190         struct debug_obj *obj;
 191         int cnt = 0;
 192
 193         hlist_for_each_entry(obj, &b->list, node) {
 194                 cnt++;
 195                 if (obj->object == addr)
 196                         return obj;
 197         }
 198         if (cnt > debug_objects_maxchain)
 199                 debug_objects_maxchain = cnt;
 200
 201         return NULL;
 202 }
 203
 204 /*
 205  * Allocate a new object from the hlist
 206  */
 207 static struct debug_obj *__alloc_object(struct hlist_head *list)
 208 {
 209         struct debug_obj *obj = NULL;
 210
 211         if (list->first) {
 212                 obj = hlist_entry(list->first, typeof(*obj), node);
 213                 hlist_del(&obj->node);
 214         }
 215
 216         return obj;
 217 }
 218
 219 static struct debug_obj *
 220 alloc_object(void *addr, struct debug_bucket *b, const struct debug_obj_descr *descr)
 221 {
 222         struct debug_percpu_free *percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 223         struct debug_obj *obj;
 224
 225         if (likely(obj_cache)) {
 226                 obj = __alloc_object(&percpu_pool->free_objs);
 227                 if (obj) {
 228                         percpu_pool->obj_free--;
 229                         goto init_obj;
 230                 }
 231         }
 232
 233         raw_spin_lock(&pool_lock);
 234         obj = __alloc_object(&obj_pool);
 235         if (obj) {
 236                 obj_pool_used++;
 237                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 238
 239                 /*
 240                  * Looking ahead, allocate one batch of debug objects and
 241                  * put them into the percpu free pool.
 242                  */
 243                 if (likely(obj_cache)) {
 244                         int i;
 245
 246                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 247                                 struct debug_obj *obj2;
 248
 249                                 obj2 = __alloc_object(&obj_pool);
 250                                 if (!obj2)
 251                                         break;
 252                                 hlist_add_head(&obj2->node,
 253                                                &percpu_pool->free_objs);
 254                                 percpu_pool->obj_free++;
 255                                 obj_pool_used++;
 256                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 257                         }
 258                 }
 259
 260                 if (obj_pool_used > obj_pool_max_used)
 261                         obj_pool_max_used = obj_pool_used;
 262
 263                 if (obj_pool_free < obj_pool_min_free)
 264                         obj_pool_min_free = obj_pool_free;
 265         }
 266         raw_spin_unlock(&pool_lock);
 267
 268 init_obj:
 269         if (obj) {
 270                 obj->object = addr;
 271                 obj->descr  = descr;
 272                 obj->state  = ODEBUG_STATE_NONE;
 273                 obj->astate = 0;
 274                 hlist_add_head(&obj->node, &b->list);
 275         }
 276         return obj;
 277 }
 278
 279 /*
 280  * workqueue function to free objects.
 281  *
 282  * To reduce contention on the global pool_lock, the actual freeing of
 283  * debug objects will be delayed if the pool_lock is busy.
 284  */
 285 static void free_obj_work(struct work_struct *work)
 286 {
 287         struct hlist_node *tmp;
 288         struct debug_obj *obj;
 289         unsigned long flags;
 290         HLIST_HEAD(tofree);
 291
 292         WRITE_ONCE(obj_freeing, false);
 293         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 294                 return;
 295
 296         if (obj_pool_free >= debug_objects_pool_size)
 297                 goto free_objs;
 298
 299         /*
 300          * The objs on the pool list might be allocated before the work is
 301          * run, so recheck if pool list it full or not, if not fill pool
 302          * list from the global free list. As it is likely that a workload
 303          * may be gearing up to use more and more objects, don't free any
 304          * of them until the next round.
 305          */
 306         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 307                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 308                 hlist_del(&obj->node);
 309                 hlist_add_head(&obj->node, &obj_pool);
 310                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 311                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree - 1);
 312         }
 313         raw_spin_unlock_irqrestore(&pool_lock, flags);
 314         return;
 315
 316 free_objs:
 317         /*
 318          * Pool list is already full and there are still objs on the free
 319          * list. Move remaining free objs to a temporary list to free the
 320          * memory outside the pool_lock held region.
 321          */
 322         if (obj_nr_tofree) {
 323                 hlist_move_list(&obj_to_free, &tofree);
 324                 debug_objects_freed += obj_nr_tofree;
 325                 WRITE_ONCE(obj_nr_tofree, 0);
 326         }
 327         raw_spin_unlock_irqrestore(&pool_lock, flags);
 328
 329         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 330                 hlist_del(&obj->node);
 331                 kmem_cache_free(obj_cache, obj);
 332         }
 333 }
 334
 335 static void __free_object(struct debug_obj *obj)
 336 {
 337         struct debug_obj *objs[ODEBUG_BATCH_SIZE];
 338         struct debug_percpu_free *percpu_pool;
 339         int lookahead_count = 0;
 340         unsigned long flags;
 341         bool work;
 342
 343         local_irq_save(flags);
 344         if (!obj_cache)
 345                 goto free_to_obj_pool;
 346
 347         /*
 348          * Try to free it into the percpu pool first.
 349          */
 350         percpu_pool = this_cpu_ptr(&percpu_obj_pool);
 351         if (percpu_pool->obj_free < ODEBUG_POOL_PERCPU_SIZE) {
 352                 hlist_add_head(&obj->node, &percpu_pool->free_objs);
 353                 percpu_pool->obj_free++;
 354                 local_irq_restore(flags);
 355                 return;
 356         }
 357
 358         /*
 359          * As the percpu pool is full, look ahead and pull out a batch
 360          * of objects from the percpu pool and free them as well.
 361          */
 362         for (; lookahead_count < ODEBUG_BATCH_SIZE; lookahead_count++) {
 363                 objs[lookahead_count] = __alloc_object(&percpu_pool->free_objs);
 364                 if (!objs[lookahead_count])
 365                         break;
 366                 percpu_pool->obj_free--;
 367         }
 368
 369 free_to_obj_pool:
 370         raw_spin_lock(&pool_lock);
 371         work = (obj_pool_free > debug_objects_pool_size) && obj_cache &&
 372                (obj_nr_tofree < ODEBUG_FREE_WORK_MAX);
 373         obj_pool_used--;
 374
 375         if (work) {
 376                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 377                 hlist_add_head(&obj->node, &obj_to_free);
 378                 if (lookahead_count) {
 379                         WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + lookahead_count);
 380                         obj_pool_used -= lookahead_count;
 381                         while (lookahead_count) {
 382                                 hlist_add_head(&objs[--lookahead_count]->node,
 383                                                &obj_to_free);
 384                         }
 385                 }
 386
 387                 if ((obj_pool_free > debug_objects_pool_size) &&
 388                     (obj_nr_tofree < ODEBUG_FREE_WORK_MAX)) {
 389                         int i;
 390
 391                         /*
 392                          * Free one more batch of objects from obj_pool.
 393                          */
 394                         for (i = 0; i < ODEBUG_BATCH_SIZE; i++) {
 395                                 obj = __alloc_object(&obj_pool);
 396                                 hlist_add_head(&obj->node, &obj_to_free);
 397                                 WRITE_ONCE(obj_pool_free, obj_pool_free - 1);
 398                                 WRITE_ONCE(obj_nr_tofree, obj_nr_tofree + 1);
 399                         }
 400                 }
 401         } else {
 402                 WRITE_ONCE(obj_pool_free, obj_pool_free + 1);
 403                 hlist_add_head(&obj->node, &obj_pool);
 404                 if (lookahead_count) {
 405                         WRITE_ONCE(obj_pool_free, obj_pool_free + lookahead_count);
 406                         obj_pool_used -= lookahead_count;
 407                         while (lookahead_count) {
 408                                 hlist_add_head(&objs[--lookahead_count]->node,
 409                                                &obj_pool);
 410                         }
 411                 }
 412         }
 413         raw_spin_unlock(&pool_lock);
 414         local_irq_restore(flags);
 415 }
 416
 417 /*
 418  * Put the object back into the pool and schedule work to free objects
 419  * if necessary.
 420  */
 421 static void free_object(struct debug_obj *obj)
 422 {
 423         __free_object(obj);
 424         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
 425                 WRITE_ONCE(obj_freeing, true);
 426                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
 427         }
 428 }
 429
 430 #ifdef CONFIG_HOTPLUG_CPU
 431 static int object_cpu_offline(unsigned int cpu)
 432 {
 433         struct debug_percpu_free *percpu_pool;
 434         struct hlist_node *tmp;
 435         struct debug_obj *obj;
 436         unsigned long flags;
 437
 438         /* Remote access is safe as the CPU is dead already */
 439         percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu);
 440         hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) {
 441                 hlist_del(&obj->node);
 442                 kmem_cache_free(obj_cache, obj);
 443         }
 444
 445         raw_spin_lock_irqsave(&pool_lock, flags);
 446         obj_pool_used -= percpu_pool->obj_free;
 447         debug_objects_freed += percpu_pool->obj_free;
 448         raw_spin_unlock_irqrestore(&pool_lock, flags);
 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: %p object type: %s hint: %pS\n",
 507                         msg, obj_states[obj->state], obj->astate,
 508                         obj->object, 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 struct debug_obj *lookup_object_or_alloc(void *addr, struct debug_bucket *b,
 552                                                 const struct debug_obj_descr *descr,
 553                                                 bool onstack, bool alloc_ifstatic)
 554 {
 555         struct debug_obj *obj = lookup_object(addr, b);
 556         enum debug_obj_state state = ODEBUG_STATE_NONE;
 557
 558         if (likely(obj))
 559                 return obj;
 560
 561         /*
 562          * debug_object_init() unconditionally allocates untracked
 563          * objects. It does not matter whether it is a static object or
 564          * not.
 565          *
 566          * debug_object_assert_init() and debug_object_activate() allow
 567          * allocation only if the descriptor callback confirms that the
 568          * object is static and considered initialized. For non-static
 569          * objects the allocation needs to be done from the fixup callback.
 570          */
 571         if (unlikely(alloc_ifstatic)) {
 572                 if (!descr->is_static_object || !descr->is_static_object(addr))
 573                         return ERR_PTR(-ENOENT);
 574                 /* Statically allocated objects are considered initialized */
 575                 state = ODEBUG_STATE_INIT;
 576         }
 577
 578         obj = alloc_object(addr, b, descr);
 579         if (likely(obj)) {
 580                 obj->state = state;
 581                 debug_object_is_on_stack(addr, onstack);
 582                 return obj;
 583         }
 584
 585         /* Out of memory. Do the cleanup outside of the locked region */
 586         debug_objects_enabled = 0;
 587         return NULL;
 588 }
 589
 590 static void
 591 __debug_object_init(void *addr, const struct debug_obj_descr *descr, int onstack)
 592 {
 593         enum debug_obj_state state;
 594         struct debug_bucket *db;
 595         struct debug_obj *obj;
 596         unsigned long flags;
 597
 598         /*
 599          * On RT enabled kernels the pool refill must happen in preemptible
 600          * context:
 601          */
 602         if (!IS_ENABLED(CONFIG_PREEMPT_RT) || preemptible())
 603                 fill_pool();
 604
 605         db = get_bucket((unsigned long) addr);
 606
 607         raw_spin_lock_irqsave(&db->lock, flags);
 608
 609         obj = lookup_object_or_alloc(addr, db, descr, onstack, false);
 610         if (unlikely(!obj)) {
 611                 raw_spin_unlock_irqrestore(&db->lock, flags);
 612                 debug_objects_oom();
 613                 return;
 614         }
 615
 616         switch (obj->state) {
 617         case ODEBUG_STATE_NONE:
 618         case ODEBUG_STATE_INIT:
 619         case ODEBUG_STATE_INACTIVE:
 620                 obj->state = ODEBUG_STATE_INIT;
 621                 break;
 622
 623         case ODEBUG_STATE_ACTIVE:
 624                 state = obj->state;
 625                 raw_spin_unlock_irqrestore(&db->lock, flags);
 626                 debug_print_object(obj, "init");
 627                 debug_object_fixup(descr->fixup_init, addr, state);
 628                 return;
 629
 630         case ODEBUG_STATE_DESTROYED:
 631                 raw_spin_unlock_irqrestore(&db->lock, flags);
 632                 debug_print_object(obj, "init");
 633                 return;
 634         default:
 635                 break;
 636         }
 637
 638         raw_spin_unlock_irqrestore(&db->lock, flags);
 639 }
 640
 641 /**
 642  * debug_object_init - debug checks when an object is initialized
 643  * @addr:       address of the object
 644  * @descr:      pointer to an object specific debug description structure
 645  */
 646 void debug_object_init(void *addr, const struct debug_obj_descr *descr)
 647 {
 648         if (!debug_objects_enabled)
 649                 return;
 650
 651         __debug_object_init(addr, descr, 0);
 652 }
 653 EXPORT_SYMBOL_GPL(debug_object_init);
 654
 655 /**
 656  * debug_object_init_on_stack - debug checks when an object on stack is
 657  *                              initialized
 658  * @addr:       address of the object
 659  * @descr:      pointer to an object specific debug description structure
 660  */
 661 void debug_object_init_on_stack(void *addr, const struct debug_obj_descr *descr)
 662 {
 663         if (!debug_objects_enabled)
 664                 return;
 665
 666         __debug_object_init(addr, descr, 1);
 667 }
 668 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 669
 670 /**
 671  * debug_object_activate - debug checks when an object is activated
 672  * @addr:       address of the object
 673  * @descr:      pointer to an object specific debug description structure
 674  * Returns 0 for success, -EINVAL for check failed.
 675  */
 676 int debug_object_activate(void *addr, const struct debug_obj_descr *descr)
 677 {
 678         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 679         enum debug_obj_state state;
 680         struct debug_bucket *db;
 681         struct debug_obj *obj;
 682         unsigned long flags;
 683         int ret;
 684
 685         if (!debug_objects_enabled)
 686                 return 0;
 687
 688         db = get_bucket((unsigned long) addr);
 689
 690         raw_spin_lock_irqsave(&db->lock, flags);
 691
 692         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 693         if (likely(!IS_ERR_OR_NULL(obj))) {
 694                 bool print_object = false;
 695
 696                 switch (obj->state) {
 697                 case ODEBUG_STATE_INIT:
 698                 case ODEBUG_STATE_INACTIVE:
 699                         obj->state = ODEBUG_STATE_ACTIVE;
 700                         ret = 0;
 701                         break;
 702
 703                 case ODEBUG_STATE_ACTIVE:
 704                         state = obj->state;
 705                         raw_spin_unlock_irqrestore(&db->lock, flags);
 706                         debug_print_object(obj, "activate");
 707                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 708                         return ret ? 0 : -EINVAL;
 709
 710                 case ODEBUG_STATE_DESTROYED:
 711                         print_object = true;
 712                         ret = -EINVAL;
 713                         break;
 714                 default:
 715                         ret = 0;
 716                         break;
 717                 }
 718                 raw_spin_unlock_irqrestore(&db->lock, flags);
 719                 if (print_object)
 720                         debug_print_object(obj, "activate");
 721                 return ret;
 722         }
 723
 724         raw_spin_unlock_irqrestore(&db->lock, flags);
 725
 726         /* If NULL the allocation has hit OOM */
 727         if (!obj) {
 728                 debug_objects_oom();
 729                 return 0;
 730         }
 731
 732         /* Object is neither static nor tracked. It's not initialized */
 733         debug_print_object(&o, "activate");
 734         ret = debug_object_fixup(descr->fixup_activate, addr, ODEBUG_STATE_NOTAVAILABLE);
 735         return ret ? 0 : -EINVAL;
 736 }
 737 EXPORT_SYMBOL_GPL(debug_object_activate);
 738
 739 /**
 740  * debug_object_deactivate - debug checks when an object is deactivated
 741  * @addr:       address of the object
 742  * @descr:      pointer to an object specific debug description structure
 743  */
 744 void debug_object_deactivate(void *addr, const struct debug_obj_descr *descr)
 745 {
 746         struct debug_bucket *db;
 747         struct debug_obj *obj;
 748         unsigned long flags;
 749         bool print_object = false;
 750
 751         if (!debug_objects_enabled)
 752                 return;
 753
 754         db = get_bucket((unsigned long) addr);
 755
 756         raw_spin_lock_irqsave(&db->lock, flags);
 757
 758         obj = lookup_object(addr, db);
 759         if (obj) {
 760                 switch (obj->state) {
 761                 case ODEBUG_STATE_INIT:
 762                 case ODEBUG_STATE_INACTIVE:
 763                 case ODEBUG_STATE_ACTIVE:
 764                         if (!obj->astate)
 765                                 obj->state = ODEBUG_STATE_INACTIVE;
 766                         else
 767                                 print_object = true;
 768                         break;
 769
 770                 case ODEBUG_STATE_DESTROYED:
 771                         print_object = true;
 772                         break;
 773                 default:
 774                         break;
 775                 }
 776         }
 777
 778         raw_spin_unlock_irqrestore(&db->lock, flags);
 779         if (!obj) {
 780                 struct debug_obj o = { .object = addr,
 781                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 782                                        .descr = descr };
 783
 784                 debug_print_object(&o, "deactivate");
 785         } else if (print_object) {
 786                 debug_print_object(obj, "deactivate");
 787         }
 788 }
 789 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 790
 791 /**
 792  * debug_object_destroy - debug checks when an object is destroyed
 793  * @addr:       address of the object
 794  * @descr:      pointer to an object specific debug description structure
 795  */
 796 void debug_object_destroy(void *addr, const struct debug_obj_descr *descr)
 797 {
 798         enum debug_obj_state state;
 799         struct debug_bucket *db;
 800         struct debug_obj *obj;
 801         unsigned long flags;
 802         bool print_object = false;
 803
 804         if (!debug_objects_enabled)
 805                 return;
 806
 807         db = get_bucket((unsigned long) addr);
 808
 809         raw_spin_lock_irqsave(&db->lock, flags);
 810
 811         obj = lookup_object(addr, db);
 812         if (!obj)
 813                 goto out_unlock;
 814
 815         switch (obj->state) {
 816         case ODEBUG_STATE_NONE:
 817         case ODEBUG_STATE_INIT:
 818         case ODEBUG_STATE_INACTIVE:
 819                 obj->state = ODEBUG_STATE_DESTROYED;
 820                 break;
 821         case ODEBUG_STATE_ACTIVE:
 822                 state = obj->state;
 823                 raw_spin_unlock_irqrestore(&db->lock, flags);
 824                 debug_print_object(obj, "destroy");
 825                 debug_object_fixup(descr->fixup_destroy, addr, state);
 826                 return;
 827
 828         case ODEBUG_STATE_DESTROYED:
 829                 print_object = true;
 830                 break;
 831         default:
 832                 break;
 833         }
 834 out_unlock:
 835         raw_spin_unlock_irqrestore(&db->lock, flags);
 836         if (print_object)
 837                 debug_print_object(obj, "destroy");
 838 }
 839 EXPORT_SYMBOL_GPL(debug_object_destroy);
 840
 841 /**
 842  * debug_object_free - debug checks when an object is freed
 843  * @addr:       address of the object
 844  * @descr:      pointer to an object specific debug description structure
 845  */
 846 void debug_object_free(void *addr, const struct debug_obj_descr *descr)
 847 {
 848         enum debug_obj_state state;
 849         struct debug_bucket *db;
 850         struct debug_obj *obj;
 851         unsigned long flags;
 852
 853         if (!debug_objects_enabled)
 854                 return;
 855
 856         db = get_bucket((unsigned long) addr);
 857
 858         raw_spin_lock_irqsave(&db->lock, flags);
 859
 860         obj = lookup_object(addr, db);
 861         if (!obj)
 862                 goto out_unlock;
 863
 864         switch (obj->state) {
 865         case ODEBUG_STATE_ACTIVE:
 866                 state = obj->state;
 867                 raw_spin_unlock_irqrestore(&db->lock, flags);
 868                 debug_print_object(obj, "free");
 869                 debug_object_fixup(descr->fixup_free, addr, state);
 870                 return;
 871         default:
 872                 hlist_del(&obj->node);
 873                 raw_spin_unlock_irqrestore(&db->lock, flags);
 874                 free_object(obj);
 875                 return;
 876         }
 877 out_unlock:
 878         raw_spin_unlock_irqrestore(&db->lock, flags);
 879 }
 880 EXPORT_SYMBOL_GPL(debug_object_free);
 881
 882 /**
 883  * debug_object_assert_init - debug checks when object should be init-ed
 884  * @addr:       address of the object
 885  * @descr:      pointer to an object specific debug description structure
 886  */
 887 void debug_object_assert_init(void *addr, const struct debug_obj_descr *descr)
 888 {
 889         struct debug_obj o = { .object = addr, .state = ODEBUG_STATE_NOTAVAILABLE, .descr = descr };
 890         struct debug_bucket *db;
 891         struct debug_obj *obj;
 892         unsigned long flags;
 893
 894         if (!debug_objects_enabled)
 895                 return;
 896
 897         db = get_bucket((unsigned long) addr);
 898
 899         raw_spin_lock_irqsave(&db->lock, flags);
 900         obj = lookup_object_or_alloc(addr, db, descr, false, true);
 901         raw_spin_unlock_irqrestore(&db->lock, flags);
 902         if (likely(!IS_ERR_OR_NULL(obj)))
 903                 return;
 904
 905         /* If NULL the allocation has hit OOM */
 906         if (!obj) {
 907                 debug_objects_oom();
 908                 return;
 909         }
 910
 911         /* Object is neither tracked nor static. It's not initialized. */
 912         debug_print_object(&o, "assert_init");
 913         debug_object_fixup(descr->fixup_assert_init, addr, ODEBUG_STATE_NOTAVAILABLE);
 914 }
 915 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 916
 917 /**
 918  * debug_object_active_state - debug checks object usage state machine
 919  * @addr:       address of the object
 920  * @descr:      pointer to an object specific debug description structure
 921  * @expect:     expected state
 922  * @next:       state to move to if expected state is found
 923  */
 924 void
 925 debug_object_active_state(void *addr, const struct debug_obj_descr *descr,
 926                           unsigned int expect, unsigned int next)
 927 {
 928         struct debug_bucket *db;
 929         struct debug_obj *obj;
 930         unsigned long flags;
 931         bool print_object = false;
 932
 933         if (!debug_objects_enabled)
 934                 return;
 935
 936         db = get_bucket((unsigned long) addr);
 937
 938         raw_spin_lock_irqsave(&db->lock, flags);
 939
 940         obj = lookup_object(addr, db);
 941         if (obj) {
 942                 switch (obj->state) {
 943                 case ODEBUG_STATE_ACTIVE:
 944                         if (obj->astate == expect)
 945                                 obj->astate = next;
 946                         else
 947                                 print_object = true;
 948                         break;
 949
 950                 default:
 951                         print_object = true;
 952                         break;
 953                 }
 954         }
 955
 956         raw_spin_unlock_irqrestore(&db->lock, flags);
 957         if (!obj) {
 958                 struct debug_obj o = { .object = addr,
 959                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 960                                        .descr = descr };
 961
 962                 debug_print_object(&o, "active_state");
 963         } else if (print_object) {
 964                 debug_print_object(obj, "active_state");
 965         }
 966 }
 967 EXPORT_SYMBOL_GPL(debug_object_active_state);
 968
 969 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 970 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 971 {
 972         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 973         const struct debug_obj_descr *descr;
 974         enum debug_obj_state state;
 975         struct debug_bucket *db;
 976         struct hlist_node *tmp;
 977         struct debug_obj *obj;
 978         int cnt, objs_checked = 0;
 979
 980         saddr = (unsigned long) address;
 981         eaddr = saddr + size;
 982         paddr = saddr & ODEBUG_CHUNK_MASK;
 983         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 984         chunks >>= ODEBUG_CHUNK_SHIFT;
 985
 986         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 987                 db = get_bucket(paddr);
 988
 989 repeat:
 990                 cnt = 0;
 991                 raw_spin_lock_irqsave(&db->lock, flags);
 992                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 993                         cnt++;
 994                         oaddr = (unsigned long) obj->object;
 995                         if (oaddr < saddr || oaddr >= eaddr)
 996                                 continue;
 997
 998                         switch (obj->state) {
 999                         case ODEBUG_STATE_ACTIVE:
1000                                 descr = obj->descr;
1001                                 state = obj->state;
1002                                 raw_spin_unlock_irqrestore(&db->lock, flags);
1003                                 debug_print_object(obj, "free");
1004                                 debug_object_fixup(descr->fixup_free,
1005                                                    (void *) oaddr, state);
1006                                 goto repeat;
1007                         default:
1008                                 hlist_del(&obj->node);
1009                                 __free_object(obj);
1010                                 break;
1011                         }
1012                 }
1013                 raw_spin_unlock_irqrestore(&db->lock, flags);
1014
1015                 if (cnt > debug_objects_maxchain)
1016                         debug_objects_maxchain = cnt;
1017
1018                 objs_checked += cnt;
1019         }
1020
1021         if (objs_checked > debug_objects_maxchecked)
1022                 debug_objects_maxchecked = objs_checked;
1023
1024         /* Schedule work to actually kmem_cache_free() objects */
1025         if (!READ_ONCE(obj_freeing) && READ_ONCE(obj_nr_tofree)) {
1026                 WRITE_ONCE(obj_freeing, true);
1027                 schedule_delayed_work(&debug_obj_work, ODEBUG_FREE_WORK_DELAY);
1028         }
1029 }
1030
1031 void debug_check_no_obj_freed(const void *address, unsigned long size)
1032 {
1033         if (debug_objects_enabled)
1034                 __debug_check_no_obj_freed(address, size);
1035 }
1036 #endif
1037
1038 #ifdef CONFIG_DEBUG_FS
1039
1040 static int debug_stats_show(struct seq_file *m, void *v)
1041 {
1042         int cpu, obj_percpu_free = 0;
1043
1044         for_each_possible_cpu(cpu)
1045                 obj_percpu_free += per_cpu(percpu_obj_pool.obj_free, cpu);
1046
1047         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
1048         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
1049         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
1050         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
1051         seq_printf(m, "pool_free     :%d\n", READ_ONCE(obj_pool_free) + obj_percpu_free);
1052         seq_printf(m, "pool_pcp_free :%d\n", obj_percpu_free);
1053         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
1054         seq_printf(m, "pool_used     :%d\n", obj_pool_used - obj_percpu_free);
1055         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
1056         seq_printf(m, "on_free_list  :%d\n", READ_ONCE(obj_nr_tofree));
1057         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
1058         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
1059         return 0;
1060 }
1061 DEFINE_SHOW_ATTRIBUTE(debug_stats);
1062
1063 static int __init debug_objects_init_debugfs(void)
1064 {
1065         struct dentry *dbgdir;
1066
1067         if (!debug_objects_enabled)
1068                 return 0;
1069
1070         dbgdir = debugfs_create_dir("debug_objects", NULL);
1071
1072         debugfs_create_file("stats", 0444, dbgdir, NULL, &debug_stats_fops);
1073
1074         return 0;
1075 }
1076 __initcall(debug_objects_init_debugfs);
1077
1078 #else
1079 static inline void debug_objects_init_debugfs(void) { }
1080 #endif
1081
1082 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
1083
1084 /* Random data structure for the self test */
1085 struct self_test {
1086         unsigned long   dummy1[6];
1087         int             static_init;
1088         unsigned long   dummy2[3];
1089 };
1090
1091 static __initconst const struct debug_obj_descr descr_type_test;
1092
1093 static bool __init is_static_object(void *addr)
1094 {
1095         struct self_test *obj = addr;
1096
1097         return obj->static_init;
1098 }
1099
1100 /*
1101  * fixup_init is called when:
1102  * - an active object is initialized
1103  */
1104 static bool __init fixup_init(void *addr, enum debug_obj_state state)
1105 {
1106         struct self_test *obj = addr;
1107
1108         switch (state) {
1109         case ODEBUG_STATE_ACTIVE:
1110                 debug_object_deactivate(obj, &descr_type_test);
1111                 debug_object_init(obj, &descr_type_test);
1112                 return true;
1113         default:
1114                 return false;
1115         }
1116 }
1117
1118 /*
1119  * fixup_activate is called when:
1120  * - an active object is activated
1121  * - an unknown non-static object is activated
1122  */
1123 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
1124 {
1125         struct self_test *obj = addr;
1126
1127         switch (state) {
1128         case ODEBUG_STATE_NOTAVAILABLE:
1129                 return true;
1130         case ODEBUG_STATE_ACTIVE:
1131                 debug_object_deactivate(obj, &descr_type_test);
1132                 debug_object_activate(obj, &descr_type_test);
1133                 return true;
1134
1135         default:
1136                 return false;
1137         }
1138 }
1139
1140 /*
1141  * fixup_destroy is called when:
1142  * - an active object is destroyed
1143  */
1144 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
1145 {
1146         struct self_test *obj = addr;
1147
1148         switch (state) {
1149         case ODEBUG_STATE_ACTIVE:
1150                 debug_object_deactivate(obj, &descr_type_test);
1151                 debug_object_destroy(obj, &descr_type_test);
1152                 return true;
1153         default:
1154                 return false;
1155         }
1156 }
1157
1158 /*
1159  * fixup_free is called when:
1160  * - an active object is freed
1161  */
1162 static bool __init fixup_free(void *addr, enum debug_obj_state state)
1163 {
1164         struct self_test *obj = addr;
1165
1166         switch (state) {
1167         case ODEBUG_STATE_ACTIVE:
1168                 debug_object_deactivate(obj, &descr_type_test);
1169                 debug_object_free(obj, &descr_type_test);
1170                 return true;
1171         default:
1172                 return false;
1173         }
1174 }
1175
1176 static int __init
1177 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
1178 {
1179         struct debug_bucket *db;
1180         struct debug_obj *obj;
1181         unsigned long flags;
1182         int res = -EINVAL;
1183
1184         db = get_bucket((unsigned long) addr);
1185
1186         raw_spin_lock_irqsave(&db->lock, flags);
1187
1188         obj = lookup_object(addr, db);
1189         if (!obj && state != ODEBUG_STATE_NONE) {
1190                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1191                 goto out;
1192         }
1193         if (obj && obj->state != state) {
1194                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1195                        obj->state, state);
1196                 goto out;
1197         }
1198         if (fixups != debug_objects_fixups) {
1199                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1200                        fixups, debug_objects_fixups);
1201                 goto out;
1202         }
1203         if (warnings != debug_objects_warnings) {
1204                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1205                        warnings, debug_objects_warnings);
1206                 goto out;
1207         }
1208         res = 0;
1209 out:
1210         raw_spin_unlock_irqrestore(&db->lock, flags);
1211         if (res)
1212                 debug_objects_enabled = 0;
1213         return res;
1214 }
1215
1216 static __initconst const struct debug_obj_descr descr_type_test = {
1217         .name                   = "selftest",
1218         .is_static_object       = is_static_object,
1219         .fixup_init             = fixup_init,
1220         .fixup_activate         = fixup_activate,
1221         .fixup_destroy          = fixup_destroy,
1222         .fixup_free             = fixup_free,
1223 };
1224
1225 static __initdata struct self_test obj = { .static_init = 0 };
1226
1227 static void __init debug_objects_selftest(void)
1228 {
1229         int fixups, oldfixups, warnings, oldwarnings;
1230         unsigned long flags;
1231
1232         local_irq_save(flags);
1233
1234         fixups = oldfixups = debug_objects_fixups;
1235         warnings = oldwarnings = debug_objects_warnings;
1236         descr_test = &descr_type_test;
1237
1238         debug_object_init(&obj, &descr_type_test);
1239         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1240                 goto out;
1241         debug_object_activate(&obj, &descr_type_test);
1242         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1243                 goto out;
1244         debug_object_activate(&obj, &descr_type_test);
1245         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1246                 goto out;
1247         debug_object_deactivate(&obj, &descr_type_test);
1248         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1249                 goto out;
1250         debug_object_destroy(&obj, &descr_type_test);
1251         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1252                 goto out;
1253         debug_object_init(&obj, &descr_type_test);
1254         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1255                 goto out;
1256         debug_object_activate(&obj, &descr_type_test);
1257         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1258                 goto out;
1259         debug_object_deactivate(&obj, &descr_type_test);
1260         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1261                 goto out;
1262         debug_object_free(&obj, &descr_type_test);
1263         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1264                 goto out;
1265
1266         obj.static_init = 1;
1267         debug_object_activate(&obj, &descr_type_test);
1268         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1269                 goto out;
1270         debug_object_init(&obj, &descr_type_test);
1271         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1272                 goto out;
1273         debug_object_free(&obj, &descr_type_test);
1274         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1275                 goto out;
1276
1277 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1278         debug_object_init(&obj, &descr_type_test);
1279         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1280                 goto out;
1281         debug_object_activate(&obj, &descr_type_test);
1282         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1283                 goto out;
1284         __debug_check_no_obj_freed(&obj, sizeof(obj));
1285         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1286                 goto out;
1287 #endif
1288         pr_info("selftest passed\n");
1289
1290 out:
1291         debug_objects_fixups = oldfixups;
1292         debug_objects_warnings = oldwarnings;
1293         descr_test = NULL;
1294
1295         local_irq_restore(flags);
1296 }
1297 #else
1298 static inline void debug_objects_selftest(void) { }
1299 #endif
1300
1301 /*
1302  * Called during early boot to initialize the hash buckets and link
1303  * the static object pool objects into the poll list. After this call
1304  * the object tracker is fully operational.
1305  */
1306 void __init debug_objects_early_init(void)
1307 {
1308         int i;
1309
1310         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1311                 raw_spin_lock_init(&obj_hash[i].lock);
1312
1313         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1314                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1315 }
1316
1317 /*
1318  * Convert the statically allocated objects to dynamic ones:
1319  */
1320 static int __init debug_objects_replace_static_objects(void)
1321 {
1322         struct debug_bucket *db = obj_hash;
1323         struct hlist_node *tmp;
1324         struct debug_obj *obj, *new;
1325         HLIST_HEAD(objects);
1326         int i, cnt = 0;
1327
1328         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1329                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1330                 if (!obj)
1331                         goto free;
1332                 hlist_add_head(&obj->node, &objects);
1333         }
1334
1335         debug_objects_allocated += i;
1336
1337         /*
1338          * debug_objects_mem_init() is now called early that only one CPU is up
1339          * and interrupts have been disabled, so it is safe to replace the
1340          * active object references.
1341          */
1342
1343         /* Remove the statically allocated objects from the pool */
1344         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1345                 hlist_del(&obj->node);
1346         /* Move the allocated objects to the pool */
1347         hlist_move_list(&objects, &obj_pool);
1348
1349         /* Replace the active object references */
1350         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1351                 hlist_move_list(&db->list, &objects);
1352
1353                 hlist_for_each_entry(obj, &objects, node) {
1354                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1355                         hlist_del(&new->node);
1356                         /* copy object data */
1357                         *new = *obj;
1358                         hlist_add_head(&new->node, &db->list);
1359                         cnt++;
1360                 }
1361         }
1362
1363         pr_debug("%d of %d active objects replaced\n",
1364                  cnt, obj_pool_used);
1365         return 0;
1366 free:
1367         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1368                 hlist_del(&obj->node);
1369                 kmem_cache_free(obj_cache, obj);
1370         }
1371         return -ENOMEM;
1372 }
1373
1374 /*
1375  * Called after the kmem_caches are functional to setup a dedicated
1376  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1377  * prevents that the debug code is called on kmem_cache_free() for the
1378  * debug tracker objects to avoid recursive calls.
1379  */
1380 void __init debug_objects_mem_init(void)
1381 {
1382         int cpu, extras;
1383
1384         if (!debug_objects_enabled)
1385                 return;
1386
1387         /*
1388          * Initialize the percpu object pools
1389          *
1390          * Initialization is not strictly necessary, but was done for
1391          * completeness.
1392          */
1393         for_each_possible_cpu(cpu)
1394                 INIT_HLIST_HEAD(&per_cpu(percpu_obj_pool.free_objs, cpu));
1395
1396         obj_cache = kmem_cache_create("debug_objects_cache",
1397                                       sizeof (struct debug_obj), 0,
1398                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1399                                       NULL);
1400
1401         if (!obj_cache || debug_objects_replace_static_objects()) {
1402                 debug_objects_enabled = 0;
1403                 kmem_cache_destroy(obj_cache);
1404                 pr_warn("out of memory.\n");
1405                 return;
1406         } else
1407                 debug_objects_selftest();
1408
1409 #ifdef CONFIG_HOTPLUG_CPU
1410         cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL,
1411                                         object_cpu_offline);
1412 #endif
1413
1414         /*
1415          * Increase the thresholds for allocating and freeing objects
1416          * according to the number of possible CPUs available in the system.
1417          */
1418         extras = num_possible_cpus() * ODEBUG_BATCH_SIZE;
1419         debug_objects_pool_size += extras;
1420         debug_objects_pool_min_level += extras;
1421 }