git.rot13.org Git - linux/blob - lib/debugobjects.c

   1 /*
   2  * Generic infrastructure for lifetime debugging of objects.
   3  *
   4  * Started by Thomas Gleixner
   5  *
   6  * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
   7  *
   8  * For licencing details see kernel-base/COPYING
   9  */
  10
  11 #define pr_fmt(fmt) "ODEBUG: " fmt
  12
  13 #include <linux/debugobjects.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/sched.h>
  16 #include <linux/sched/task_stack.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/slab.h>
  20 #include <linux/hash.h>
  21 #include <linux/kmemleak.h>
  22
  23 #define ODEBUG_HASH_BITS        14
  24 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  25
  26 #define ODEBUG_POOL_SIZE        1024
  27 #define ODEBUG_POOL_MIN_LEVEL   256
  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 struct debug_bucket {
  34         struct hlist_head       list;
  35         raw_spinlock_t          lock;
  36 };
  37
  38 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  39
  40 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  41
  42 static DEFINE_RAW_SPINLOCK(pool_lock);
  43
  44 static HLIST_HEAD(obj_pool);
  45 static HLIST_HEAD(obj_to_free);
  46
  47 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  48 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  49 static int                      obj_pool_used;
  50 static int                      obj_pool_max_used;
  51 /* The number of objs on the global free list */
  52 static int                      obj_nr_tofree;
  53 static struct kmem_cache        *obj_cache;
  54
  55 static int                      debug_objects_maxchain __read_mostly;
  56 static int __maybe_unused       debug_objects_maxchecked __read_mostly;
  57 static int                      debug_objects_fixups __read_mostly;
  58 static int                      debug_objects_warnings __read_mostly;
  59 static int                      debug_objects_enabled __read_mostly
  60                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  61 static int                      debug_objects_pool_size __read_mostly
  62                                 = ODEBUG_POOL_SIZE;
  63 static int                      debug_objects_pool_min_level __read_mostly
  64                                 = ODEBUG_POOL_MIN_LEVEL;
  65 static struct debug_obj_descr   *descr_test  __read_mostly;
  66
  67 /*
  68  * Track numbers of kmem_cache_alloc()/free() calls done.
  69  */
  70 static int                      debug_objects_allocated;
  71 static int                      debug_objects_freed;
  72
  73 static void free_obj_work(struct work_struct *work);
  74 static DECLARE_WORK(debug_obj_work, free_obj_work);
  75
  76 static int __init enable_object_debug(char *str)
  77 {
  78         debug_objects_enabled = 1;
  79         return 0;
  80 }
  81
  82 static int __init disable_object_debug(char *str)
  83 {
  84         debug_objects_enabled = 0;
  85         return 0;
  86 }
  87
  88 early_param("debug_objects", enable_object_debug);
  89 early_param("no_debug_objects", disable_object_debug);
  90
  91 static const char *obj_states[ODEBUG_STATE_MAX] = {
  92         [ODEBUG_STATE_NONE]             = "none",
  93         [ODEBUG_STATE_INIT]             = "initialized",
  94         [ODEBUG_STATE_INACTIVE]         = "inactive",
  95         [ODEBUG_STATE_ACTIVE]           = "active",
  96         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  97         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  98 };
  99
 100 static void fill_pool(void)
 101 {
 102         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
 103         struct debug_obj *new, *obj;
 104         unsigned long flags;
 105
 106         if (likely(obj_pool_free >= debug_objects_pool_min_level))
 107                 return;
 108
 109         /*
 110          * Reuse objs from the global free list; they will be reinitialized
 111          * when allocating.
 112          */
 113         while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 114                 raw_spin_lock_irqsave(&pool_lock, flags);
 115                 /*
 116                  * Recheck with the lock held as the worker thread might have
 117                  * won the race and freed the global free list already.
 118                  */
 119                 if (obj_nr_tofree) {
 120                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 121                         hlist_del(&obj->node);
 122                         obj_nr_tofree--;
 123                         hlist_add_head(&obj->node, &obj_pool);
 124                         obj_pool_free++;
 125                 }
 126                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 127         }
 128
 129         if (unlikely(!obj_cache))
 130                 return;
 131
 132         while (obj_pool_free < debug_objects_pool_min_level) {
 133
 134                 new = kmem_cache_zalloc(obj_cache, gfp);
 135                 if (!new)
 136                         return;
 137
 138                 raw_spin_lock_irqsave(&pool_lock, flags);
 139                 hlist_add_head(&new->node, &obj_pool);
 140                 debug_objects_allocated++;
 141                 obj_pool_free++;
 142                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 143         }
 144 }
 145
 146 /*
 147  * Lookup an object in the hash bucket.
 148  */
 149 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 150 {
 151         struct debug_obj *obj;
 152         int cnt = 0;
 153
 154         hlist_for_each_entry(obj, &b->list, node) {
 155                 cnt++;
 156                 if (obj->object == addr)
 157                         return obj;
 158         }
 159         if (cnt > debug_objects_maxchain)
 160                 debug_objects_maxchain = cnt;
 161
 162         return NULL;
 163 }
 164
 165 /*
 166  * Allocate a new object. If the pool is empty, switch off the debugger.
 167  * Must be called with interrupts disabled.
 168  */
 169 static struct debug_obj *
 170 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 171 {
 172         struct debug_obj *obj = NULL;
 173
 174         raw_spin_lock(&pool_lock);
 175         if (obj_pool.first) {
 176                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 177
 178                 obj->object = addr;
 179                 obj->descr  = descr;
 180                 obj->state  = ODEBUG_STATE_NONE;
 181                 obj->astate = 0;
 182                 hlist_del(&obj->node);
 183
 184                 hlist_add_head(&obj->node, &b->list);
 185
 186                 obj_pool_used++;
 187                 if (obj_pool_used > obj_pool_max_used)
 188                         obj_pool_max_used = obj_pool_used;
 189
 190                 obj_pool_free--;
 191                 if (obj_pool_free < obj_pool_min_free)
 192                         obj_pool_min_free = obj_pool_free;
 193         }
 194         raw_spin_unlock(&pool_lock);
 195
 196         return obj;
 197 }
 198
 199 /*
 200  * workqueue function to free objects.
 201  *
 202  * To reduce contention on the global pool_lock, the actual freeing of
 203  * debug objects will be delayed if the pool_lock is busy.
 204  */
 205 static void free_obj_work(struct work_struct *work)
 206 {
 207         struct hlist_node *tmp;
 208         struct debug_obj *obj;
 209         unsigned long flags;
 210         HLIST_HEAD(tofree);
 211
 212         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 213                 return;
 214
 215         /*
 216          * The objs on the pool list might be allocated before the work is
 217          * run, so recheck if pool list it full or not, if not fill pool
 218          * list from the global free list
 219          */
 220         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 221                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 222                 hlist_del(&obj->node);
 223                 hlist_add_head(&obj->node, &obj_pool);
 224                 obj_pool_free++;
 225                 obj_nr_tofree--;
 226         }
 227
 228         /*
 229          * Pool list is already full and there are still objs on the free
 230          * list. Move remaining free objs to a temporary list to free the
 231          * memory outside the pool_lock held region.
 232          */
 233         if (obj_nr_tofree) {
 234                 hlist_move_list(&obj_to_free, &tofree);
 235                 debug_objects_freed += obj_nr_tofree;
 236                 obj_nr_tofree = 0;
 237         }
 238         raw_spin_unlock_irqrestore(&pool_lock, flags);
 239
 240         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 241                 hlist_del(&obj->node);
 242                 kmem_cache_free(obj_cache, obj);
 243         }
 244 }
 245
 246 static bool __free_object(struct debug_obj *obj)
 247 {
 248         unsigned long flags;
 249         bool work;
 250
 251         raw_spin_lock_irqsave(&pool_lock, flags);
 252         work = (obj_pool_free > debug_objects_pool_size) && obj_cache;
 253         obj_pool_used--;
 254
 255         if (work) {
 256                 obj_nr_tofree++;
 257                 hlist_add_head(&obj->node, &obj_to_free);
 258         } else {
 259                 obj_pool_free++;
 260                 hlist_add_head(&obj->node, &obj_pool);
 261         }
 262         raw_spin_unlock_irqrestore(&pool_lock, flags);
 263         return work;
 264 }
 265
 266 /*
 267  * Put the object back into the pool and schedule work to free objects
 268  * if necessary.
 269  */
 270 static void free_object(struct debug_obj *obj)
 271 {
 272         if (__free_object(obj))
 273                 schedule_work(&debug_obj_work);
 274 }
 275
 276 /*
 277  * We run out of memory. That means we probably have tons of objects
 278  * allocated.
 279  */
 280 static void debug_objects_oom(void)
 281 {
 282         struct debug_bucket *db = obj_hash;
 283         struct hlist_node *tmp;
 284         HLIST_HEAD(freelist);
 285         struct debug_obj *obj;
 286         unsigned long flags;
 287         int i;
 288
 289         pr_warn("Out of memory. ODEBUG disabled\n");
 290
 291         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 292                 raw_spin_lock_irqsave(&db->lock, flags);
 293                 hlist_move_list(&db->list, &freelist);
 294                 raw_spin_unlock_irqrestore(&db->lock, flags);
 295
 296                 /* Now free them */
 297                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 298                         hlist_del(&obj->node);
 299                         free_object(obj);
 300                 }
 301         }
 302 }
 303
 304 /*
 305  * We use the pfn of the address for the hash. That way we can check
 306  * for freed objects simply by checking the affected bucket.
 307  */
 308 static struct debug_bucket *get_bucket(unsigned long addr)
 309 {
 310         unsigned long hash;
 311
 312         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 313         return &obj_hash[hash];
 314 }
 315
 316 static void debug_print_object(struct debug_obj *obj, char *msg)
 317 {
 318         struct debug_obj_descr *descr = obj->descr;
 319         static int limit;
 320
 321         if (limit < 5 && descr != descr_test) {
 322                 void *hint = descr->debug_hint ?
 323                         descr->debug_hint(obj->object) : NULL;
 324                 limit++;
 325                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 326                                  "object type: %s hint: %pS\n",
 327                         msg, obj_states[obj->state], obj->astate,
 328                         descr->name, hint);
 329         }
 330         debug_objects_warnings++;
 331 }
 332
 333 /*
 334  * Try to repair the damage, so we have a better chance to get useful
 335  * debug output.
 336  */
 337 static bool
 338 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 339                    void * addr, enum debug_obj_state state)
 340 {
 341         if (fixup && fixup(addr, state)) {
 342                 debug_objects_fixups++;
 343                 return true;
 344         }
 345         return false;
 346 }
 347
 348 static void debug_object_is_on_stack(void *addr, int onstack)
 349 {
 350         int is_on_stack;
 351         static int limit;
 352
 353         if (limit > 4)
 354                 return;
 355
 356         is_on_stack = object_is_on_stack(addr);
 357         if (is_on_stack == onstack)
 358                 return;
 359
 360         limit++;
 361         if (is_on_stack)
 362                 pr_warn("object %p is on stack %p, but NOT annotated.\n", addr,
 363                          task_stack_page(current));
 364         else
 365                 pr_warn("object %p is NOT on stack %p, but annotated.\n", addr,
 366                          task_stack_page(current));
 367
 368         WARN_ON(1);
 369 }
 370
 371 static void
 372 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 373 {
 374         enum debug_obj_state state;
 375         struct debug_bucket *db;
 376         struct debug_obj *obj;
 377         unsigned long flags;
 378         bool check_object_on_stack = false;
 379
 380         fill_pool();
 381
 382         db = get_bucket((unsigned long) addr);
 383
 384         raw_spin_lock_irqsave(&db->lock, flags);
 385
 386         obj = lookup_object(addr, db);
 387         if (!obj) {
 388                 obj = alloc_object(addr, db, descr);
 389                 if (!obj) {
 390                         debug_objects_enabled = 0;
 391                         raw_spin_unlock_irqrestore(&db->lock, flags);
 392                         debug_objects_oom();
 393                         return;
 394                 }
 395                 check_object_on_stack = true;
 396         }
 397
 398         switch (obj->state) {
 399         case ODEBUG_STATE_NONE:
 400         case ODEBUG_STATE_INIT:
 401         case ODEBUG_STATE_INACTIVE:
 402                 obj->state = ODEBUG_STATE_INIT;
 403                 break;
 404
 405         case ODEBUG_STATE_ACTIVE:
 406                 state = obj->state;
 407                 raw_spin_unlock_irqrestore(&db->lock, flags);
 408                 debug_print_object(obj, "init");
 409                 debug_object_fixup(descr->fixup_init, addr, state);
 410                 return;
 411
 412         case ODEBUG_STATE_DESTROYED:
 413                 raw_spin_unlock_irqrestore(&db->lock, flags);
 414                 debug_print_object(obj, "init");
 415                 return;
 416         default:
 417                 break;
 418         }
 419
 420         raw_spin_unlock_irqrestore(&db->lock, flags);
 421         if (check_object_on_stack)
 422                 debug_object_is_on_stack(addr, onstack);
 423
 424 }
 425
 426 /**
 427  * debug_object_init - debug checks when an object is initialized
 428  * @addr:       address of the object
 429  * @descr:      pointer to an object specific debug description structure
 430  */
 431 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 432 {
 433         if (!debug_objects_enabled)
 434                 return;
 435
 436         __debug_object_init(addr, descr, 0);
 437 }
 438 EXPORT_SYMBOL_GPL(debug_object_init);
 439
 440 /**
 441  * debug_object_init_on_stack - debug checks when an object on stack is
 442  *                              initialized
 443  * @addr:       address of the object
 444  * @descr:      pointer to an object specific debug description structure
 445  */
 446 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 447 {
 448         if (!debug_objects_enabled)
 449                 return;
 450
 451         __debug_object_init(addr, descr, 1);
 452 }
 453 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 454
 455 /**
 456  * debug_object_activate - debug checks when an object is activated
 457  * @addr:       address of the object
 458  * @descr:      pointer to an object specific debug description structure
 459  * Returns 0 for success, -EINVAL for check failed.
 460  */
 461 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 462 {
 463         enum debug_obj_state state;
 464         struct debug_bucket *db;
 465         struct debug_obj *obj;
 466         unsigned long flags;
 467         int ret;
 468         struct debug_obj o = { .object = addr,
 469                                .state = ODEBUG_STATE_NOTAVAILABLE,
 470                                .descr = descr };
 471
 472         if (!debug_objects_enabled)
 473                 return 0;
 474
 475         db = get_bucket((unsigned long) addr);
 476
 477         raw_spin_lock_irqsave(&db->lock, flags);
 478
 479         obj = lookup_object(addr, db);
 480         if (obj) {
 481                 ret = 0;
 482                 switch (obj->state) {
 483                 case ODEBUG_STATE_INIT:
 484                 case ODEBUG_STATE_INACTIVE:
 485                         obj->state = ODEBUG_STATE_ACTIVE;
 486                         break;
 487
 488                 case ODEBUG_STATE_ACTIVE:
 489                         state = obj->state;
 490                         raw_spin_unlock_irqrestore(&db->lock, flags);
 491                         debug_print_object(obj, "activate");
 492                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 493                         return ret ? 0 : -EINVAL;
 494
 495                 case ODEBUG_STATE_DESTROYED:
 496                         ret = -EINVAL;
 497                         break;
 498                 default:
 499                         break;
 500                 }
 501                 raw_spin_unlock_irqrestore(&db->lock, flags);
 502                 if (ret)
 503                         debug_print_object(obj, "activate");
 504                 return ret;
 505         }
 506
 507         raw_spin_unlock_irqrestore(&db->lock, flags);
 508
 509         /*
 510          * We are here when a static object is activated. We
 511          * let the type specific code confirm whether this is
 512          * true or not. if true, we just make sure that the
 513          * static object is tracked in the object tracker. If
 514          * not, this must be a bug, so we try to fix it up.
 515          */
 516         if (descr->is_static_object && descr->is_static_object(addr)) {
 517                 /* track this static object */
 518                 debug_object_init(addr, descr);
 519                 debug_object_activate(addr, descr);
 520         } else {
 521                 debug_print_object(&o, "activate");
 522                 ret = debug_object_fixup(descr->fixup_activate, addr,
 523                                         ODEBUG_STATE_NOTAVAILABLE);
 524                 return ret ? 0 : -EINVAL;
 525         }
 526         return 0;
 527 }
 528 EXPORT_SYMBOL_GPL(debug_object_activate);
 529
 530 /**
 531  * debug_object_deactivate - debug checks when an object is deactivated
 532  * @addr:       address of the object
 533  * @descr:      pointer to an object specific debug description structure
 534  */
 535 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 536 {
 537         struct debug_bucket *db;
 538         struct debug_obj *obj;
 539         unsigned long flags;
 540
 541         if (!debug_objects_enabled)
 542                 return;
 543
 544         db = get_bucket((unsigned long) addr);
 545
 546         raw_spin_lock_irqsave(&db->lock, flags);
 547
 548         obj = lookup_object(addr, db);
 549         if (obj) {
 550                 switch (obj->state) {
 551                 case ODEBUG_STATE_INIT:
 552                 case ODEBUG_STATE_INACTIVE:
 553                 case ODEBUG_STATE_ACTIVE:
 554                         if (!obj->astate)
 555                                 obj->state = ODEBUG_STATE_INACTIVE;
 556                         else
 557                                 goto out_unlock_print;
 558                         break;
 559
 560                 case ODEBUG_STATE_DESTROYED:
 561                         goto out_unlock_print;
 562
 563                 default:
 564                         break;
 565                 }
 566         }
 567
 568         raw_spin_unlock_irqrestore(&db->lock, flags);
 569         if (!obj) {
 570                 struct debug_obj o = { .object = addr,
 571                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 572                                        .descr = descr };
 573
 574                 debug_print_object(&o, "deactivate");
 575         }
 576         return;
 577
 578 out_unlock_print:
 579         raw_spin_unlock_irqrestore(&db->lock, flags);
 580         debug_print_object(obj, "deactivate");
 581 }
 582 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 583
 584 /**
 585  * debug_object_destroy - debug checks when an object is destroyed
 586  * @addr:       address of the object
 587  * @descr:      pointer to an object specific debug description structure
 588  */
 589 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 590 {
 591         enum debug_obj_state state;
 592         struct debug_bucket *db;
 593         struct debug_obj *obj;
 594         unsigned long flags;
 595
 596         if (!debug_objects_enabled)
 597                 return;
 598
 599         db = get_bucket((unsigned long) addr);
 600
 601         raw_spin_lock_irqsave(&db->lock, flags);
 602
 603         obj = lookup_object(addr, db);
 604         if (!obj)
 605                 goto out_unlock;
 606
 607         switch (obj->state) {
 608         case ODEBUG_STATE_NONE:
 609         case ODEBUG_STATE_INIT:
 610         case ODEBUG_STATE_INACTIVE:
 611                 obj->state = ODEBUG_STATE_DESTROYED;
 612                 break;
 613         case ODEBUG_STATE_ACTIVE:
 614                 state = obj->state;
 615                 raw_spin_unlock_irqrestore(&db->lock, flags);
 616                 debug_print_object(obj, "destroy");
 617                 debug_object_fixup(descr->fixup_destroy, addr, state);
 618                 return;
 619
 620         case ODEBUG_STATE_DESTROYED:
 621                 raw_spin_unlock_irqrestore(&db->lock, flags);
 622                 debug_print_object(obj, "destroy");
 623                 return;
 624         default:
 625                 break;
 626         }
 627 out_unlock:
 628         raw_spin_unlock_irqrestore(&db->lock, flags);
 629 }
 630 EXPORT_SYMBOL_GPL(debug_object_destroy);
 631
 632 /**
 633  * debug_object_free - debug checks when an object is freed
 634  * @addr:       address of the object
 635  * @descr:      pointer to an object specific debug description structure
 636  */
 637 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 638 {
 639         enum debug_obj_state state;
 640         struct debug_bucket *db;
 641         struct debug_obj *obj;
 642         unsigned long flags;
 643
 644         if (!debug_objects_enabled)
 645                 return;
 646
 647         db = get_bucket((unsigned long) addr);
 648
 649         raw_spin_lock_irqsave(&db->lock, flags);
 650
 651         obj = lookup_object(addr, db);
 652         if (!obj)
 653                 goto out_unlock;
 654
 655         switch (obj->state) {
 656         case ODEBUG_STATE_ACTIVE:
 657                 state = obj->state;
 658                 raw_spin_unlock_irqrestore(&db->lock, flags);
 659                 debug_print_object(obj, "free");
 660                 debug_object_fixup(descr->fixup_free, addr, state);
 661                 return;
 662         default:
 663                 hlist_del(&obj->node);
 664                 raw_spin_unlock_irqrestore(&db->lock, flags);
 665                 free_object(obj);
 666                 return;
 667         }
 668 out_unlock:
 669         raw_spin_unlock_irqrestore(&db->lock, flags);
 670 }
 671 EXPORT_SYMBOL_GPL(debug_object_free);
 672
 673 /**
 674  * debug_object_assert_init - debug checks when object should be init-ed
 675  * @addr:       address of the object
 676  * @descr:      pointer to an object specific debug description structure
 677  */
 678 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 679 {
 680         struct debug_bucket *db;
 681         struct debug_obj *obj;
 682         unsigned long flags;
 683
 684         if (!debug_objects_enabled)
 685                 return;
 686
 687         db = get_bucket((unsigned long) addr);
 688
 689         raw_spin_lock_irqsave(&db->lock, flags);
 690
 691         obj = lookup_object(addr, db);
 692         if (!obj) {
 693                 struct debug_obj o = { .object = addr,
 694                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 695                                        .descr = descr };
 696
 697                 raw_spin_unlock_irqrestore(&db->lock, flags);
 698                 /*
 699                  * Maybe the object is static, and we let the type specific
 700                  * code confirm. Track this static object if true, else invoke
 701                  * fixup.
 702                  */
 703                 if (descr->is_static_object && descr->is_static_object(addr)) {
 704                         /* Track this static object */
 705                         debug_object_init(addr, descr);
 706                 } else {
 707                         debug_print_object(&o, "assert_init");
 708                         debug_object_fixup(descr->fixup_assert_init, addr,
 709                                            ODEBUG_STATE_NOTAVAILABLE);
 710                 }
 711                 return;
 712         }
 713
 714         raw_spin_unlock_irqrestore(&db->lock, flags);
 715 }
 716 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 717
 718 /**
 719  * debug_object_active_state - debug checks object usage state machine
 720  * @addr:       address of the object
 721  * @descr:      pointer to an object specific debug description structure
 722  * @expect:     expected state
 723  * @next:       state to move to if expected state is found
 724  */
 725 void
 726 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 727                           unsigned int expect, unsigned int next)
 728 {
 729         struct debug_bucket *db;
 730         struct debug_obj *obj;
 731         unsigned long flags;
 732
 733         if (!debug_objects_enabled)
 734                 return;
 735
 736         db = get_bucket((unsigned long) addr);
 737
 738         raw_spin_lock_irqsave(&db->lock, flags);
 739
 740         obj = lookup_object(addr, db);
 741         if (obj) {
 742                 switch (obj->state) {
 743                 case ODEBUG_STATE_ACTIVE:
 744                         if (obj->astate == expect)
 745                                 obj->astate = next;
 746                         else
 747                                 goto out_unlock_print;
 748                         break;
 749
 750                 default:
 751                         goto out_unlock_print;
 752                 }
 753         }
 754
 755         raw_spin_unlock_irqrestore(&db->lock, flags);
 756         if (!obj) {
 757                 struct debug_obj o = { .object = addr,
 758                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 759                                        .descr = descr };
 760
 761                 debug_print_object(&o, "active_state");
 762         }
 763         return;
 764
 765 out_unlock_print:
 766         raw_spin_unlock_irqrestore(&db->lock, flags);
 767         debug_print_object(obj, "active_state");
 768 }
 769 EXPORT_SYMBOL_GPL(debug_object_active_state);
 770
 771 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 772 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 773 {
 774         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 775         struct debug_obj_descr *descr;
 776         enum debug_obj_state state;
 777         struct debug_bucket *db;
 778         struct hlist_node *tmp;
 779         struct debug_obj *obj;
 780         int cnt, objs_checked = 0;
 781         bool work = false;
 782
 783         saddr = (unsigned long) address;
 784         eaddr = saddr + size;
 785         paddr = saddr & ODEBUG_CHUNK_MASK;
 786         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 787         chunks >>= ODEBUG_CHUNK_SHIFT;
 788
 789         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 790                 db = get_bucket(paddr);
 791
 792 repeat:
 793                 cnt = 0;
 794                 raw_spin_lock_irqsave(&db->lock, flags);
 795                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 796                         cnt++;
 797                         oaddr = (unsigned long) obj->object;
 798                         if (oaddr < saddr || oaddr >= eaddr)
 799                                 continue;
 800
 801                         switch (obj->state) {
 802                         case ODEBUG_STATE_ACTIVE:
 803                                 descr = obj->descr;
 804                                 state = obj->state;
 805                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 806                                 debug_print_object(obj, "free");
 807                                 debug_object_fixup(descr->fixup_free,
 808                                                    (void *) oaddr, state);
 809                                 goto repeat;
 810                         default:
 811                                 hlist_del(&obj->node);
 812                                 work |= __free_object(obj);
 813                                 break;
 814                         }
 815                 }
 816                 raw_spin_unlock_irqrestore(&db->lock, flags);
 817
 818                 if (cnt > debug_objects_maxchain)
 819                         debug_objects_maxchain = cnt;
 820
 821                 objs_checked += cnt;
 822         }
 823
 824         if (objs_checked > debug_objects_maxchecked)
 825                 debug_objects_maxchecked = objs_checked;
 826
 827         /* Schedule work to actually kmem_cache_free() objects */
 828         if (work)
 829                 schedule_work(&debug_obj_work);
 830 }
 831
 832 void debug_check_no_obj_freed(const void *address, unsigned long size)
 833 {
 834         if (debug_objects_enabled)
 835                 __debug_check_no_obj_freed(address, size);
 836 }
 837 #endif
 838
 839 #ifdef CONFIG_DEBUG_FS
 840
 841 static int debug_stats_show(struct seq_file *m, void *v)
 842 {
 843         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 844         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
 845         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 846         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 847         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 848         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 849         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 850         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 851         seq_printf(m, "on_free_list  :%d\n", obj_nr_tofree);
 852         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 853         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 854         return 0;
 855 }
 856
 857 static int debug_stats_open(struct inode *inode, struct file *filp)
 858 {
 859         return single_open(filp, debug_stats_show, NULL);
 860 }
 861
 862 static const struct file_operations debug_stats_fops = {
 863         .open           = debug_stats_open,
 864         .read           = seq_read,
 865         .llseek         = seq_lseek,
 866         .release        = single_release,
 867 };
 868
 869 static int __init debug_objects_init_debugfs(void)
 870 {
 871         struct dentry *dbgdir, *dbgstats;
 872
 873         if (!debug_objects_enabled)
 874                 return 0;
 875
 876         dbgdir = debugfs_create_dir("debug_objects", NULL);
 877         if (!dbgdir)
 878                 return -ENOMEM;
 879
 880         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 881                                        &debug_stats_fops);
 882         if (!dbgstats)
 883                 goto err;
 884
 885         return 0;
 886
 887 err:
 888         debugfs_remove(dbgdir);
 889
 890         return -ENOMEM;
 891 }
 892 __initcall(debug_objects_init_debugfs);
 893
 894 #else
 895 static inline void debug_objects_init_debugfs(void) { }
 896 #endif
 897
 898 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 899
 900 /* Random data structure for the self test */
 901 struct self_test {
 902         unsigned long   dummy1[6];
 903         int             static_init;
 904         unsigned long   dummy2[3];
 905 };
 906
 907 static __initdata struct debug_obj_descr descr_type_test;
 908
 909 static bool __init is_static_object(void *addr)
 910 {
 911         struct self_test *obj = addr;
 912
 913         return obj->static_init;
 914 }
 915
 916 /*
 917  * fixup_init is called when:
 918  * - an active object is initialized
 919  */
 920 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 921 {
 922         struct self_test *obj = addr;
 923
 924         switch (state) {
 925         case ODEBUG_STATE_ACTIVE:
 926                 debug_object_deactivate(obj, &descr_type_test);
 927                 debug_object_init(obj, &descr_type_test);
 928                 return true;
 929         default:
 930                 return false;
 931         }
 932 }
 933
 934 /*
 935  * fixup_activate is called when:
 936  * - an active object is activated
 937  * - an unknown non-static object is activated
 938  */
 939 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 940 {
 941         struct self_test *obj = addr;
 942
 943         switch (state) {
 944         case ODEBUG_STATE_NOTAVAILABLE:
 945                 return true;
 946         case ODEBUG_STATE_ACTIVE:
 947                 debug_object_deactivate(obj, &descr_type_test);
 948                 debug_object_activate(obj, &descr_type_test);
 949                 return true;
 950
 951         default:
 952                 return false;
 953         }
 954 }
 955
 956 /*
 957  * fixup_destroy is called when:
 958  * - an active object is destroyed
 959  */
 960 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 961 {
 962         struct self_test *obj = addr;
 963
 964         switch (state) {
 965         case ODEBUG_STATE_ACTIVE:
 966                 debug_object_deactivate(obj, &descr_type_test);
 967                 debug_object_destroy(obj, &descr_type_test);
 968                 return true;
 969         default:
 970                 return false;
 971         }
 972 }
 973
 974 /*
 975  * fixup_free is called when:
 976  * - an active object is freed
 977  */
 978 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 979 {
 980         struct self_test *obj = addr;
 981
 982         switch (state) {
 983         case ODEBUG_STATE_ACTIVE:
 984                 debug_object_deactivate(obj, &descr_type_test);
 985                 debug_object_free(obj, &descr_type_test);
 986                 return true;
 987         default:
 988                 return false;
 989         }
 990 }
 991
 992 static int __init
 993 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 994 {
 995         struct debug_bucket *db;
 996         struct debug_obj *obj;
 997         unsigned long flags;
 998         int res = -EINVAL;
 999         enum debug_obj_state obj_state;
1000
1001         db = get_bucket((unsigned long) addr);
1002
1003         raw_spin_lock_irqsave(&db->lock, flags);
1004
1005         obj = lookup_object(addr, db);
1006         obj_state = obj ? obj->state : state;
1007
1008         raw_spin_unlock_irqrestore(&db->lock, flags);
1009
1010         if (!obj && state != ODEBUG_STATE_NONE) {
1011                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
1012                 goto out;
1013         }
1014         if (obj_state != state) {
1015                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
1016                        obj_state, state);
1017                 goto out;
1018         }
1019         if (fixups != debug_objects_fixups) {
1020                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
1021                        fixups, debug_objects_fixups);
1022                 goto out;
1023         }
1024         if (warnings != debug_objects_warnings) {
1025                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1026                        warnings, debug_objects_warnings);
1027                 goto out;
1028         }
1029         res = 0;
1030 out:
1031         if (res)
1032                 debug_objects_enabled = 0;
1033         return res;
1034 }
1035
1036 static __initdata struct debug_obj_descr descr_type_test = {
1037         .name                   = "selftest",
1038         .is_static_object       = is_static_object,
1039         .fixup_init             = fixup_init,
1040         .fixup_activate         = fixup_activate,
1041         .fixup_destroy          = fixup_destroy,
1042         .fixup_free             = fixup_free,
1043 };
1044
1045 static __initdata struct self_test obj = { .static_init = 0 };
1046
1047 static void __init debug_objects_selftest(void)
1048 {
1049         int fixups, oldfixups, warnings, oldwarnings;
1050         unsigned long flags;
1051
1052         local_irq_save(flags);
1053
1054         fixups = oldfixups = debug_objects_fixups;
1055         warnings = oldwarnings = debug_objects_warnings;
1056         descr_test = &descr_type_test;
1057
1058         debug_object_init(&obj, &descr_type_test);
1059         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1060                 goto out;
1061         debug_object_activate(&obj, &descr_type_test);
1062         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1063                 goto out;
1064         debug_object_activate(&obj, &descr_type_test);
1065         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1066                 goto out;
1067         debug_object_deactivate(&obj, &descr_type_test);
1068         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1069                 goto out;
1070         debug_object_destroy(&obj, &descr_type_test);
1071         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1072                 goto out;
1073         debug_object_init(&obj, &descr_type_test);
1074         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1075                 goto out;
1076         debug_object_activate(&obj, &descr_type_test);
1077         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1078                 goto out;
1079         debug_object_deactivate(&obj, &descr_type_test);
1080         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1081                 goto out;
1082         debug_object_free(&obj, &descr_type_test);
1083         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1084                 goto out;
1085
1086         obj.static_init = 1;
1087         debug_object_activate(&obj, &descr_type_test);
1088         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1089                 goto out;
1090         debug_object_init(&obj, &descr_type_test);
1091         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1092                 goto out;
1093         debug_object_free(&obj, &descr_type_test);
1094         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1095                 goto out;
1096
1097 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1098         debug_object_init(&obj, &descr_type_test);
1099         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1100                 goto out;
1101         debug_object_activate(&obj, &descr_type_test);
1102         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1103                 goto out;
1104         __debug_check_no_obj_freed(&obj, sizeof(obj));
1105         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1106                 goto out;
1107 #endif
1108         pr_info("selftest passed\n");
1109
1110 out:
1111         debug_objects_fixups = oldfixups;
1112         debug_objects_warnings = oldwarnings;
1113         descr_test = NULL;
1114
1115         local_irq_restore(flags);
1116 }
1117 #else
1118 static inline void debug_objects_selftest(void) { }
1119 #endif
1120
1121 /*
1122  * Called during early boot to initialize the hash buckets and link
1123  * the static object pool objects into the poll list. After this call
1124  * the object tracker is fully operational.
1125  */
1126 void __init debug_objects_early_init(void)
1127 {
1128         int i;
1129
1130         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1131                 raw_spin_lock_init(&obj_hash[i].lock);
1132
1133         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1134                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1135 }
1136
1137 /*
1138  * Convert the statically allocated objects to dynamic ones:
1139  */
1140 static int __init debug_objects_replace_static_objects(void)
1141 {
1142         struct debug_bucket *db = obj_hash;
1143         struct hlist_node *tmp;
1144         struct debug_obj *obj, *new;
1145         HLIST_HEAD(objects);
1146         int i, cnt = 0;
1147
1148         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1149                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1150                 if (!obj)
1151                         goto free;
1152                 hlist_add_head(&obj->node, &objects);
1153         }
1154
1155         /*
1156          * debug_objects_mem_init() is now called early that only one CPU is up
1157          * and interrupts have been disabled, so it is safe to replace the
1158          * active object references.
1159          */
1160
1161         /* Remove the statically allocated objects from the pool */
1162         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1163                 hlist_del(&obj->node);
1164         /* Move the allocated objects to the pool */
1165         hlist_move_list(&objects, &obj_pool);
1166
1167         /* Replace the active object references */
1168         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1169                 hlist_move_list(&db->list, &objects);
1170
1171                 hlist_for_each_entry(obj, &objects, node) {
1172                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1173                         hlist_del(&new->node);
1174                         /* copy object data */
1175                         *new = *obj;
1176                         hlist_add_head(&new->node, &db->list);
1177                         cnt++;
1178                 }
1179         }
1180
1181         pr_debug("%d of %d active objects replaced\n",
1182                  cnt, obj_pool_used);
1183         return 0;
1184 free:
1185         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1186                 hlist_del(&obj->node);
1187                 kmem_cache_free(obj_cache, obj);
1188         }
1189         return -ENOMEM;
1190 }
1191
1192 /*
1193  * Called after the kmem_caches are functional to setup a dedicated
1194  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1195  * prevents that the debug code is called on kmem_cache_free() for the
1196  * debug tracker objects to avoid recursive calls.
1197  */
1198 void __init debug_objects_mem_init(void)
1199 {
1200         if (!debug_objects_enabled)
1201                 return;
1202
1203         obj_cache = kmem_cache_create("debug_objects_cache",
1204                                       sizeof (struct debug_obj), 0,
1205                                       SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE,
1206                                       NULL);
1207
1208         if (!obj_cache || debug_objects_replace_static_objects()) {
1209                 debug_objects_enabled = 0;
1210                 kmem_cache_destroy(obj_cache);
1211                 pr_warn("out of memory.\n");
1212         } else
1213                 debug_objects_selftest();
1214
1215         /*
1216          * Increase the thresholds for allocating and freeing objects
1217          * according to the number of possible CPUs available in the system.
1218          */
1219         debug_objects_pool_size += num_possible_cpus() * 32;
1220         debug_objects_pool_min_level += num_possible_cpus() * 4;
1221 }