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