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/seq_file.h>
  17 #include <linux/debugfs.h>
  18 #include <linux/slab.h>
  19 #include <linux/hash.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
  27 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  28 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  29 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  30
  31 struct debug_bucket {
  32         struct hlist_head       list;
  33         raw_spinlock_t          lock;
  34 };
  35
  36 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  37
  38 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  39
  40 static DEFINE_RAW_SPINLOCK(pool_lock);
  41
  42 static HLIST_HEAD(obj_pool);
  43
  44 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  45 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  46 static int                      obj_pool_used;
  47 static int                      obj_pool_max_used;
  48 static struct kmem_cache        *obj_cache;
  49
  50 static int                      debug_objects_maxchain __read_mostly;
  51 static int                      debug_objects_fixups __read_mostly;
  52 static int                      debug_objects_warnings __read_mostly;
  53 static int                      debug_objects_enabled __read_mostly
  54                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  55 static int                      debug_objects_pool_size __read_mostly
  56                                 = ODEBUG_POOL_SIZE;
  57 static int                      debug_objects_pool_min_level __read_mostly
  58                                 = ODEBUG_POOL_MIN_LEVEL;
  59 static struct debug_obj_descr   *descr_test  __read_mostly;
  60
  61 /*
  62  * Track numbers of kmem_cache_alloc and kmem_cache_free done.
  63  */
  64 static int                      debug_objects_alloc;
  65 static int                      debug_objects_freed;
  66
  67 static void free_obj_work(struct work_struct *work);
  68 static DECLARE_WORK(debug_obj_work, free_obj_work);
  69
  70 static int __init enable_object_debug(char *str)
  71 {
  72         debug_objects_enabled = 1;
  73         return 0;
  74 }
  75
  76 static int __init disable_object_debug(char *str)
  77 {
  78         debug_objects_enabled = 0;
  79         return 0;
  80 }
  81
  82 early_param("debug_objects", enable_object_debug);
  83 early_param("no_debug_objects", disable_object_debug);
  84
  85 static const char *obj_states[ODEBUG_STATE_MAX] = {
  86         [ODEBUG_STATE_NONE]             = "none",
  87         [ODEBUG_STATE_INIT]             = "initialized",
  88         [ODEBUG_STATE_INACTIVE]         = "inactive",
  89         [ODEBUG_STATE_ACTIVE]           = "active",
  90         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  91         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  92 };
  93
  94 static void fill_pool(void)
  95 {
  96         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  97         struct debug_obj *new;
  98         unsigned long flags;
  99
 100         if (likely(obj_pool_free >= debug_objects_pool_min_level))
 101                 return;
 102
 103         if (unlikely(!obj_cache))
 104                 return;
 105
 106         while (obj_pool_free < debug_objects_pool_min_level) {
 107
 108                 new = kmem_cache_zalloc(obj_cache, gfp);
 109                 if (!new)
 110                         return;
 111
 112                 raw_spin_lock_irqsave(&pool_lock, flags);
 113                 hlist_add_head(&new->node, &obj_pool);
 114                 debug_objects_alloc++;
 115                 obj_pool_free++;
 116                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 117         }
 118 }
 119
 120 /*
 121  * Lookup an object in the hash bucket.
 122  */
 123 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 124 {
 125         struct debug_obj *obj;
 126         int cnt = 0;
 127
 128         hlist_for_each_entry(obj, &b->list, node) {
 129                 cnt++;
 130                 if (obj->object == addr)
 131                         return obj;
 132         }
 133         if (cnt > debug_objects_maxchain)
 134                 debug_objects_maxchain = cnt;
 135
 136         return NULL;
 137 }
 138
 139 /*
 140  * Allocate a new object. If the pool is empty, switch off the debugger.
 141  * Must be called with interrupts disabled.
 142  */
 143 static struct debug_obj *
 144 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 145 {
 146         struct debug_obj *obj = NULL;
 147
 148         raw_spin_lock(&pool_lock);
 149         if (obj_pool.first) {
 150                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 151
 152                 obj->object = addr;
 153                 obj->descr  = descr;
 154                 obj->state  = ODEBUG_STATE_NONE;
 155                 obj->astate = 0;
 156                 hlist_del(&obj->node);
 157
 158                 hlist_add_head(&obj->node, &b->list);
 159
 160                 obj_pool_used++;
 161                 if (obj_pool_used > obj_pool_max_used)
 162                         obj_pool_max_used = obj_pool_used;
 163
 164                 obj_pool_free--;
 165                 if (obj_pool_free < obj_pool_min_free)
 166                         obj_pool_min_free = obj_pool_free;
 167         }
 168         raw_spin_unlock(&pool_lock);
 169
 170         return obj;
 171 }
 172
 173 /*
 174  * workqueue function to free objects.
 175  */
 176 static void free_obj_work(struct work_struct *work)
 177 {
 178         struct debug_obj *obj;
 179         unsigned long flags;
 180
 181         raw_spin_lock_irqsave(&pool_lock, flags);
 182         while (obj_pool_free > debug_objects_pool_size) {
 183                 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
 184                 hlist_del(&obj->node);
 185                 obj_pool_free--;
 186                 debug_objects_freed++;
 187                 /*
 188                  * We release pool_lock across kmem_cache_free() to
 189                  * avoid contention on pool_lock.
 190                  */
 191                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 192                 kmem_cache_free(obj_cache, obj);
 193                 raw_spin_lock_irqsave(&pool_lock, flags);
 194         }
 195         raw_spin_unlock_irqrestore(&pool_lock, flags);
 196 }
 197
 198 /*
 199  * Put the object back into the pool and schedule work to free objects
 200  * if necessary.
 201  */
 202 static void free_object(struct debug_obj *obj)
 203 {
 204         unsigned long flags;
 205         int sched = 0;
 206
 207         raw_spin_lock_irqsave(&pool_lock, flags);
 208         /*
 209          * schedule work when the pool is filled and the cache is
 210          * initialized:
 211          */
 212         if (obj_pool_free > debug_objects_pool_size && obj_cache)
 213                 sched = 1;
 214         hlist_add_head(&obj->node, &obj_pool);
 215         obj_pool_free++;
 216         obj_pool_used--;
 217         raw_spin_unlock_irqrestore(&pool_lock, flags);
 218         if (sched)
 219                 schedule_work(&debug_obj_work);
 220 }
 221
 222 /*
 223  * We run out of memory. That means we probably have tons of objects
 224  * allocated.
 225  */
 226 static void debug_objects_oom(void)
 227 {
 228         struct debug_bucket *db = obj_hash;
 229         struct hlist_node *tmp;
 230         HLIST_HEAD(freelist);
 231         struct debug_obj *obj;
 232         unsigned long flags;
 233         int i;
 234
 235         pr_warn("Out of memory. ODEBUG disabled\n");
 236
 237         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 238                 raw_spin_lock_irqsave(&db->lock, flags);
 239                 hlist_move_list(&db->list, &freelist);
 240                 raw_spin_unlock_irqrestore(&db->lock, flags);
 241
 242                 /* Now free them */
 243                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 244                         hlist_del(&obj->node);
 245                         free_object(obj);
 246                 }
 247         }
 248 }
 249
 250 /*
 251  * We use the pfn of the address for the hash. That way we can check
 252  * for freed objects simply by checking the affected bucket.
 253  */
 254 static struct debug_bucket *get_bucket(unsigned long addr)
 255 {
 256         unsigned long hash;
 257
 258         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 259         return &obj_hash[hash];
 260 }
 261
 262 static void debug_print_object(struct debug_obj *obj, char *msg)
 263 {
 264         struct debug_obj_descr *descr = obj->descr;
 265         static int limit;
 266
 267         if (limit < 5 && descr != descr_test) {
 268                 void *hint = descr->debug_hint ?
 269                         descr->debug_hint(obj->object) : NULL;
 270                 limit++;
 271                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 272                                  "object type: %s hint: %pS\n",
 273                         msg, obj_states[obj->state], obj->astate,
 274                         descr->name, hint);
 275         }
 276         debug_objects_warnings++;
 277 }
 278
 279 /*
 280  * Try to repair the damage, so we have a better chance to get useful
 281  * debug output.
 282  */
 283 static bool
 284 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 285                    void * addr, enum debug_obj_state state)
 286 {
 287         if (fixup && fixup(addr, state)) {
 288                 debug_objects_fixups++;
 289                 return true;
 290         }
 291         return false;
 292 }
 293
 294 static void debug_object_is_on_stack(void *addr, int onstack)
 295 {
 296         int is_on_stack;
 297         static int limit;
 298
 299         if (limit > 4)
 300                 return;
 301
 302         is_on_stack = object_is_on_stack(addr);
 303         if (is_on_stack == onstack)
 304                 return;
 305
 306         limit++;
 307         if (is_on_stack)
 308                 pr_warn("object is on stack, but not annotated\n");
 309         else
 310                 pr_warn("object is not on stack, but annotated\n");
 311         WARN_ON(1);
 312 }
 313
 314 static void
 315 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 316 {
 317         enum debug_obj_state state;
 318         struct debug_bucket *db;
 319         struct debug_obj *obj;
 320         unsigned long flags;
 321
 322         fill_pool();
 323
 324         db = get_bucket((unsigned long) addr);
 325
 326         raw_spin_lock_irqsave(&db->lock, flags);
 327
 328         obj = lookup_object(addr, db);
 329         if (!obj) {
 330                 obj = alloc_object(addr, db, descr);
 331                 if (!obj) {
 332                         debug_objects_enabled = 0;
 333                         raw_spin_unlock_irqrestore(&db->lock, flags);
 334                         debug_objects_oom();
 335                         return;
 336                 }
 337                 debug_object_is_on_stack(addr, onstack);
 338         }
 339
 340         switch (obj->state) {
 341         case ODEBUG_STATE_NONE:
 342         case ODEBUG_STATE_INIT:
 343         case ODEBUG_STATE_INACTIVE:
 344                 obj->state = ODEBUG_STATE_INIT;
 345                 break;
 346
 347         case ODEBUG_STATE_ACTIVE:
 348                 debug_print_object(obj, "init");
 349                 state = obj->state;
 350                 raw_spin_unlock_irqrestore(&db->lock, flags);
 351                 debug_object_fixup(descr->fixup_init, addr, state);
 352                 return;
 353
 354         case ODEBUG_STATE_DESTROYED:
 355                 debug_print_object(obj, "init");
 356                 break;
 357         default:
 358                 break;
 359         }
 360
 361         raw_spin_unlock_irqrestore(&db->lock, flags);
 362 }
 363
 364 /**
 365  * debug_object_init - debug checks when an object is initialized
 366  * @addr:       address of the object
 367  * @descr:      pointer to an object specific debug description structure
 368  */
 369 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 370 {
 371         if (!debug_objects_enabled)
 372                 return;
 373
 374         __debug_object_init(addr, descr, 0);
 375 }
 376 EXPORT_SYMBOL_GPL(debug_object_init);
 377
 378 /**
 379  * debug_object_init_on_stack - debug checks when an object on stack is
 380  *                              initialized
 381  * @addr:       address of the object
 382  * @descr:      pointer to an object specific debug description structure
 383  */
 384 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 385 {
 386         if (!debug_objects_enabled)
 387                 return;
 388
 389         __debug_object_init(addr, descr, 1);
 390 }
 391 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 392
 393 /**
 394  * debug_object_activate - debug checks when an object is activated
 395  * @addr:       address of the object
 396  * @descr:      pointer to an object specific debug description structure
 397  * Returns 0 for success, -EINVAL for check failed.
 398  */
 399 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 400 {
 401         enum debug_obj_state state;
 402         struct debug_bucket *db;
 403         struct debug_obj *obj;
 404         unsigned long flags;
 405         int ret;
 406         struct debug_obj o = { .object = addr,
 407                                .state = ODEBUG_STATE_NOTAVAILABLE,
 408                                .descr = descr };
 409
 410         if (!debug_objects_enabled)
 411                 return 0;
 412
 413         db = get_bucket((unsigned long) addr);
 414
 415         raw_spin_lock_irqsave(&db->lock, flags);
 416
 417         obj = lookup_object(addr, db);
 418         if (obj) {
 419                 switch (obj->state) {
 420                 case ODEBUG_STATE_INIT:
 421                 case ODEBUG_STATE_INACTIVE:
 422                         obj->state = ODEBUG_STATE_ACTIVE;
 423                         ret = 0;
 424                         break;
 425
 426                 case ODEBUG_STATE_ACTIVE:
 427                         debug_print_object(obj, "activate");
 428                         state = obj->state;
 429                         raw_spin_unlock_irqrestore(&db->lock, flags);
 430                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 431                         return ret ? 0 : -EINVAL;
 432
 433                 case ODEBUG_STATE_DESTROYED:
 434                         debug_print_object(obj, "activate");
 435                         ret = -EINVAL;
 436                         break;
 437                 default:
 438                         ret = 0;
 439                         break;
 440                 }
 441                 raw_spin_unlock_irqrestore(&db->lock, flags);
 442                 return ret;
 443         }
 444
 445         raw_spin_unlock_irqrestore(&db->lock, flags);
 446         /*
 447          * We are here when a static object is activated. We
 448          * let the type specific code confirm whether this is
 449          * true or not. if true, we just make sure that the
 450          * static object is tracked in the object tracker. If
 451          * not, this must be a bug, so we try to fix it up.
 452          */
 453         if (descr->is_static_object && descr->is_static_object(addr)) {
 454                 /* track this static object */
 455                 debug_object_init(addr, descr);
 456                 debug_object_activate(addr, descr);
 457         } else {
 458                 debug_print_object(&o, "activate");
 459                 ret = debug_object_fixup(descr->fixup_activate, addr,
 460                                         ODEBUG_STATE_NOTAVAILABLE);
 461                 return ret ? 0 : -EINVAL;
 462         }
 463         return 0;
 464 }
 465 EXPORT_SYMBOL_GPL(debug_object_activate);
 466
 467 /**
 468  * debug_object_deactivate - debug checks when an object is deactivated
 469  * @addr:       address of the object
 470  * @descr:      pointer to an object specific debug description structure
 471  */
 472 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 473 {
 474         struct debug_bucket *db;
 475         struct debug_obj *obj;
 476         unsigned long flags;
 477
 478         if (!debug_objects_enabled)
 479                 return;
 480
 481         db = get_bucket((unsigned long) addr);
 482
 483         raw_spin_lock_irqsave(&db->lock, flags);
 484
 485         obj = lookup_object(addr, db);
 486         if (obj) {
 487                 switch (obj->state) {
 488                 case ODEBUG_STATE_INIT:
 489                 case ODEBUG_STATE_INACTIVE:
 490                 case ODEBUG_STATE_ACTIVE:
 491                         if (!obj->astate)
 492                                 obj->state = ODEBUG_STATE_INACTIVE;
 493                         else
 494                                 debug_print_object(obj, "deactivate");
 495                         break;
 496
 497                 case ODEBUG_STATE_DESTROYED:
 498                         debug_print_object(obj, "deactivate");
 499                         break;
 500                 default:
 501                         break;
 502                 }
 503         } else {
 504                 struct debug_obj o = { .object = addr,
 505                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 506                                        .descr = descr };
 507
 508                 debug_print_object(&o, "deactivate");
 509         }
 510
 511         raw_spin_unlock_irqrestore(&db->lock, flags);
 512 }
 513 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 514
 515 /**
 516  * debug_object_destroy - debug checks when an object is destroyed
 517  * @addr:       address of the object
 518  * @descr:      pointer to an object specific debug description structure
 519  */
 520 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 521 {
 522         enum debug_obj_state state;
 523         struct debug_bucket *db;
 524         struct debug_obj *obj;
 525         unsigned long flags;
 526
 527         if (!debug_objects_enabled)
 528                 return;
 529
 530         db = get_bucket((unsigned long) addr);
 531
 532         raw_spin_lock_irqsave(&db->lock, flags);
 533
 534         obj = lookup_object(addr, db);
 535         if (!obj)
 536                 goto out_unlock;
 537
 538         switch (obj->state) {
 539         case ODEBUG_STATE_NONE:
 540         case ODEBUG_STATE_INIT:
 541         case ODEBUG_STATE_INACTIVE:
 542                 obj->state = ODEBUG_STATE_DESTROYED;
 543                 break;
 544         case ODEBUG_STATE_ACTIVE:
 545                 debug_print_object(obj, "destroy");
 546                 state = obj->state;
 547                 raw_spin_unlock_irqrestore(&db->lock, flags);
 548                 debug_object_fixup(descr->fixup_destroy, addr, state);
 549                 return;
 550
 551         case ODEBUG_STATE_DESTROYED:
 552                 debug_print_object(obj, "destroy");
 553                 break;
 554         default:
 555                 break;
 556         }
 557 out_unlock:
 558         raw_spin_unlock_irqrestore(&db->lock, flags);
 559 }
 560 EXPORT_SYMBOL_GPL(debug_object_destroy);
 561
 562 /**
 563  * debug_object_free - debug checks when an object is freed
 564  * @addr:       address of the object
 565  * @descr:      pointer to an object specific debug description structure
 566  */
 567 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 568 {
 569         enum debug_obj_state state;
 570         struct debug_bucket *db;
 571         struct debug_obj *obj;
 572         unsigned long flags;
 573
 574         if (!debug_objects_enabled)
 575                 return;
 576
 577         db = get_bucket((unsigned long) addr);
 578
 579         raw_spin_lock_irqsave(&db->lock, flags);
 580
 581         obj = lookup_object(addr, db);
 582         if (!obj)
 583                 goto out_unlock;
 584
 585         switch (obj->state) {
 586         case ODEBUG_STATE_ACTIVE:
 587                 debug_print_object(obj, "free");
 588                 state = obj->state;
 589                 raw_spin_unlock_irqrestore(&db->lock, flags);
 590                 debug_object_fixup(descr->fixup_free, addr, state);
 591                 return;
 592         default:
 593                 hlist_del(&obj->node);
 594                 raw_spin_unlock_irqrestore(&db->lock, flags);
 595                 free_object(obj);
 596                 return;
 597         }
 598 out_unlock:
 599         raw_spin_unlock_irqrestore(&db->lock, flags);
 600 }
 601 EXPORT_SYMBOL_GPL(debug_object_free);
 602
 603 /**
 604  * debug_object_assert_init - debug checks when object should be init-ed
 605  * @addr:       address of the object
 606  * @descr:      pointer to an object specific debug description structure
 607  */
 608 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 609 {
 610         struct debug_bucket *db;
 611         struct debug_obj *obj;
 612         unsigned long flags;
 613
 614         if (!debug_objects_enabled)
 615                 return;
 616
 617         db = get_bucket((unsigned long) addr);
 618
 619         raw_spin_lock_irqsave(&db->lock, flags);
 620
 621         obj = lookup_object(addr, db);
 622         if (!obj) {
 623                 struct debug_obj o = { .object = addr,
 624                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 625                                        .descr = descr };
 626
 627                 raw_spin_unlock_irqrestore(&db->lock, flags);
 628                 /*
 629                  * Maybe the object is static, and we let the type specific
 630                  * code confirm. Track this static object if true, else invoke
 631                  * fixup.
 632                  */
 633                 if (descr->is_static_object && descr->is_static_object(addr)) {
 634                         /* Track this static object */
 635                         debug_object_init(addr, descr);
 636                 } else {
 637                         debug_print_object(&o, "assert_init");
 638                         debug_object_fixup(descr->fixup_assert_init, addr,
 639                                            ODEBUG_STATE_NOTAVAILABLE);
 640                 }
 641                 return;
 642         }
 643
 644         raw_spin_unlock_irqrestore(&db->lock, flags);
 645 }
 646 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 647
 648 /**
 649  * debug_object_active_state - debug checks object usage state machine
 650  * @addr:       address of the object
 651  * @descr:      pointer to an object specific debug description structure
 652  * @expect:     expected state
 653  * @next:       state to move to if expected state is found
 654  */
 655 void
 656 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 657                           unsigned int expect, unsigned int next)
 658 {
 659         struct debug_bucket *db;
 660         struct debug_obj *obj;
 661         unsigned long flags;
 662
 663         if (!debug_objects_enabled)
 664                 return;
 665
 666         db = get_bucket((unsigned long) addr);
 667
 668         raw_spin_lock_irqsave(&db->lock, flags);
 669
 670         obj = lookup_object(addr, db);
 671         if (obj) {
 672                 switch (obj->state) {
 673                 case ODEBUG_STATE_ACTIVE:
 674                         if (obj->astate == expect)
 675                                 obj->astate = next;
 676                         else
 677                                 debug_print_object(obj, "active_state");
 678                         break;
 679
 680                 default:
 681                         debug_print_object(obj, "active_state");
 682                         break;
 683                 }
 684         } else {
 685                 struct debug_obj o = { .object = addr,
 686                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 687                                        .descr = descr };
 688
 689                 debug_print_object(&o, "active_state");
 690         }
 691
 692         raw_spin_unlock_irqrestore(&db->lock, flags);
 693 }
 694 EXPORT_SYMBOL_GPL(debug_object_active_state);
 695
 696 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 697 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 698 {
 699         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 700         struct hlist_node *tmp;
 701         HLIST_HEAD(freelist);
 702         struct debug_obj_descr *descr;
 703         enum debug_obj_state state;
 704         struct debug_bucket *db;
 705         struct debug_obj *obj;
 706         int cnt;
 707
 708         saddr = (unsigned long) address;
 709         eaddr = saddr + size;
 710         paddr = saddr & ODEBUG_CHUNK_MASK;
 711         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 712         chunks >>= ODEBUG_CHUNK_SHIFT;
 713
 714         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 715                 db = get_bucket(paddr);
 716
 717 repeat:
 718                 cnt = 0;
 719                 raw_spin_lock_irqsave(&db->lock, flags);
 720                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 721                         cnt++;
 722                         oaddr = (unsigned long) obj->object;
 723                         if (oaddr < saddr || oaddr >= eaddr)
 724                                 continue;
 725
 726                         switch (obj->state) {
 727                         case ODEBUG_STATE_ACTIVE:
 728                                 debug_print_object(obj, "free");
 729                                 descr = obj->descr;
 730                                 state = obj->state;
 731                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 732                                 debug_object_fixup(descr->fixup_free,
 733                                                    (void *) oaddr, state);
 734                                 goto repeat;
 735                         default:
 736                                 hlist_del(&obj->node);
 737                                 hlist_add_head(&obj->node, &freelist);
 738                                 break;
 739                         }
 740                 }
 741                 raw_spin_unlock_irqrestore(&db->lock, flags);
 742
 743                 /* Now free them */
 744                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 745                         hlist_del(&obj->node);
 746                         free_object(obj);
 747                 }
 748
 749                 if (cnt > debug_objects_maxchain)
 750                         debug_objects_maxchain = cnt;
 751         }
 752 }
 753
 754 void debug_check_no_obj_freed(const void *address, unsigned long size)
 755 {
 756         if (debug_objects_enabled)
 757                 __debug_check_no_obj_freed(address, size);
 758 }
 759 #endif
 760
 761 #ifdef CONFIG_DEBUG_FS
 762
 763 static int debug_stats_show(struct seq_file *m, void *v)
 764 {
 765         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 766         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 767         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 768         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 769         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 770         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 771         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 772         seq_printf(m, "objects_alloc :%d\n", debug_objects_alloc);
 773         seq_printf(m, "objects_freed :%d\n", debug_objects_freed);
 774         return 0;
 775 }
 776
 777 static int debug_stats_open(struct inode *inode, struct file *filp)
 778 {
 779         return single_open(filp, debug_stats_show, NULL);
 780 }
 781
 782 static const struct file_operations debug_stats_fops = {
 783         .open           = debug_stats_open,
 784         .read           = seq_read,
 785         .llseek         = seq_lseek,
 786         .release        = single_release,
 787 };
 788
 789 static int __init debug_objects_init_debugfs(void)
 790 {
 791         struct dentry *dbgdir, *dbgstats;
 792
 793         if (!debug_objects_enabled)
 794                 return 0;
 795
 796         dbgdir = debugfs_create_dir("debug_objects", NULL);
 797         if (!dbgdir)
 798                 return -ENOMEM;
 799
 800         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 801                                        &debug_stats_fops);
 802         if (!dbgstats)
 803                 goto err;
 804
 805         return 0;
 806
 807 err:
 808         debugfs_remove(dbgdir);
 809
 810         return -ENOMEM;
 811 }
 812 __initcall(debug_objects_init_debugfs);
 813
 814 #else
 815 static inline void debug_objects_init_debugfs(void) { }
 816 #endif
 817
 818 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 819
 820 /* Random data structure for the self test */
 821 struct self_test {
 822         unsigned long   dummy1[6];
 823         int             static_init;
 824         unsigned long   dummy2[3];
 825 };
 826
 827 static __initdata struct debug_obj_descr descr_type_test;
 828
 829 static bool __init is_static_object(void *addr)
 830 {
 831         struct self_test *obj = addr;
 832
 833         return obj->static_init;
 834 }
 835
 836 /*
 837  * fixup_init is called when:
 838  * - an active object is initialized
 839  */
 840 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 841 {
 842         struct self_test *obj = addr;
 843
 844         switch (state) {
 845         case ODEBUG_STATE_ACTIVE:
 846                 debug_object_deactivate(obj, &descr_type_test);
 847                 debug_object_init(obj, &descr_type_test);
 848                 return true;
 849         default:
 850                 return false;
 851         }
 852 }
 853
 854 /*
 855  * fixup_activate is called when:
 856  * - an active object is activated
 857  * - an unknown non-static object is activated
 858  */
 859 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 860 {
 861         struct self_test *obj = addr;
 862
 863         switch (state) {
 864         case ODEBUG_STATE_NOTAVAILABLE:
 865                 return true;
 866         case ODEBUG_STATE_ACTIVE:
 867                 debug_object_deactivate(obj, &descr_type_test);
 868                 debug_object_activate(obj, &descr_type_test);
 869                 return true;
 870
 871         default:
 872                 return false;
 873         }
 874 }
 875
 876 /*
 877  * fixup_destroy is called when:
 878  * - an active object is destroyed
 879  */
 880 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 881 {
 882         struct self_test *obj = addr;
 883
 884         switch (state) {
 885         case ODEBUG_STATE_ACTIVE:
 886                 debug_object_deactivate(obj, &descr_type_test);
 887                 debug_object_destroy(obj, &descr_type_test);
 888                 return true;
 889         default:
 890                 return false;
 891         }
 892 }
 893
 894 /*
 895  * fixup_free is called when:
 896  * - an active object is freed
 897  */
 898 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 899 {
 900         struct self_test *obj = addr;
 901
 902         switch (state) {
 903         case ODEBUG_STATE_ACTIVE:
 904                 debug_object_deactivate(obj, &descr_type_test);
 905                 debug_object_free(obj, &descr_type_test);
 906                 return true;
 907         default:
 908                 return false;
 909         }
 910 }
 911
 912 static int __init
 913 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 914 {
 915         struct debug_bucket *db;
 916         struct debug_obj *obj;
 917         unsigned long flags;
 918         int res = -EINVAL;
 919
 920         db = get_bucket((unsigned long) addr);
 921
 922         raw_spin_lock_irqsave(&db->lock, flags);
 923
 924         obj = lookup_object(addr, db);
 925         if (!obj && state != ODEBUG_STATE_NONE) {
 926                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 927                 goto out;
 928         }
 929         if (obj && obj->state != state) {
 930                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 931                        obj->state, state);
 932                 goto out;
 933         }
 934         if (fixups != debug_objects_fixups) {
 935                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 936                        fixups, debug_objects_fixups);
 937                 goto out;
 938         }
 939         if (warnings != debug_objects_warnings) {
 940                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 941                        warnings, debug_objects_warnings);
 942                 goto out;
 943         }
 944         res = 0;
 945 out:
 946         raw_spin_unlock_irqrestore(&db->lock, flags);
 947         if (res)
 948                 debug_objects_enabled = 0;
 949         return res;
 950 }
 951
 952 static __initdata struct debug_obj_descr descr_type_test = {
 953         .name                   = "selftest",
 954         .is_static_object       = is_static_object,
 955         .fixup_init             = fixup_init,
 956         .fixup_activate         = fixup_activate,
 957         .fixup_destroy          = fixup_destroy,
 958         .fixup_free             = fixup_free,
 959 };
 960
 961 static __initdata struct self_test obj = { .static_init = 0 };
 962
 963 static void __init debug_objects_selftest(void)
 964 {
 965         int fixups, oldfixups, warnings, oldwarnings;
 966         unsigned long flags;
 967
 968         local_irq_save(flags);
 969
 970         fixups = oldfixups = debug_objects_fixups;
 971         warnings = oldwarnings = debug_objects_warnings;
 972         descr_test = &descr_type_test;
 973
 974         debug_object_init(&obj, &descr_type_test);
 975         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 976                 goto out;
 977         debug_object_activate(&obj, &descr_type_test);
 978         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 979                 goto out;
 980         debug_object_activate(&obj, &descr_type_test);
 981         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 982                 goto out;
 983         debug_object_deactivate(&obj, &descr_type_test);
 984         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 985                 goto out;
 986         debug_object_destroy(&obj, &descr_type_test);
 987         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 988                 goto out;
 989         debug_object_init(&obj, &descr_type_test);
 990         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 991                 goto out;
 992         debug_object_activate(&obj, &descr_type_test);
 993         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 994                 goto out;
 995         debug_object_deactivate(&obj, &descr_type_test);
 996         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 997                 goto out;
 998         debug_object_free(&obj, &descr_type_test);
 999         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1000                 goto out;
1001
1002         obj.static_init = 1;
1003         debug_object_activate(&obj, &descr_type_test);
1004         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1005                 goto out;
1006         debug_object_init(&obj, &descr_type_test);
1007         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1008                 goto out;
1009         debug_object_free(&obj, &descr_type_test);
1010         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1011                 goto out;
1012
1013 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1014         debug_object_init(&obj, &descr_type_test);
1015         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1016                 goto out;
1017         debug_object_activate(&obj, &descr_type_test);
1018         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1019                 goto out;
1020         __debug_check_no_obj_freed(&obj, sizeof(obj));
1021         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1022                 goto out;
1023 #endif
1024         pr_info("selftest passed\n");
1025
1026 out:
1027         debug_objects_fixups = oldfixups;
1028         debug_objects_warnings = oldwarnings;
1029         descr_test = NULL;
1030
1031         local_irq_restore(flags);
1032 }
1033 #else
1034 static inline void debug_objects_selftest(void) { }
1035 #endif
1036
1037 /*
1038  * Called during early boot to initialize the hash buckets and link
1039  * the static object pool objects into the poll list. After this call
1040  * the object tracker is fully operational.
1041  */
1042 void __init debug_objects_early_init(void)
1043 {
1044         int i;
1045
1046         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1047                 raw_spin_lock_init(&obj_hash[i].lock);
1048
1049         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1050                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1051 }
1052
1053 /*
1054  * Convert the statically allocated objects to dynamic ones:
1055  */
1056 static int __init debug_objects_replace_static_objects(void)
1057 {
1058         struct debug_bucket *db = obj_hash;
1059         struct hlist_node *tmp;
1060         struct debug_obj *obj, *new;
1061         HLIST_HEAD(objects);
1062         int i, cnt = 0;
1063
1064         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1065                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1066                 if (!obj)
1067                         goto free;
1068                 hlist_add_head(&obj->node, &objects);
1069         }
1070
1071         /*
1072          * When debug_objects_mem_init() is called we know that only
1073          * one CPU is up, so disabling interrupts is enough
1074          * protection. This avoids the lockdep hell of lock ordering.
1075          */
1076         local_irq_disable();
1077
1078         /* Remove the statically allocated objects from the pool */
1079         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1080                 hlist_del(&obj->node);
1081         /* Move the allocated objects to the pool */
1082         hlist_move_list(&objects, &obj_pool);
1083
1084         /* Replace the active object references */
1085         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1086                 hlist_move_list(&db->list, &objects);
1087
1088                 hlist_for_each_entry(obj, &objects, node) {
1089                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1090                         hlist_del(&new->node);
1091                         /* copy object data */
1092                         *new = *obj;
1093                         hlist_add_head(&new->node, &db->list);
1094                         cnt++;
1095                 }
1096         }
1097         local_irq_enable();
1098
1099         pr_debug("%d of %d active objects replaced\n",
1100                  cnt, obj_pool_used);
1101         return 0;
1102 free:
1103         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1104                 hlist_del(&obj->node);
1105                 kmem_cache_free(obj_cache, obj);
1106         }
1107         return -ENOMEM;
1108 }
1109
1110 /*
1111  * Called after the kmem_caches are functional to setup a dedicated
1112  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1113  * prevents that the debug code is called on kmem_cache_free() for the
1114  * debug tracker objects to avoid recursive calls.
1115  */
1116 void __init debug_objects_mem_init(void)
1117 {
1118         if (!debug_objects_enabled)
1119                 return;
1120
1121         obj_cache = kmem_cache_create("debug_objects_cache",
1122                                       sizeof (struct debug_obj), 0,
1123                                       SLAB_DEBUG_OBJECTS, NULL);
1124
1125         if (!obj_cache || debug_objects_replace_static_objects()) {
1126                 debug_objects_enabled = 0;
1127                 if (obj_cache)
1128                         kmem_cache_destroy(obj_cache);
1129                 pr_warn("out of memory.\n");
1130         } else
1131                 debug_objects_selftest();
1132
1133         /*
1134          * Increase the thresholds for allocating and freeing objects
1135          * according to the number of possible CPUs available in the system.
1136          */
1137         debug_objects_pool_size += num_possible_cpus() * 32;
1138         debug_objects_pool_min_level += num_possible_cpus() * 4;
1139 }