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 <[email protected]>
   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()/free() calls done.
  63  */
  64 static int                      debug_objects_allocated;
  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_allocated++;
 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  * To reduce contention on the global pool_lock, the actual freeing of
 177  * debug objects will be delayed if the pool_lock is busy. We also free
 178  * the objects in a batch of 4 for each lock/unlock cycle.
 179  */
 180 #define ODEBUG_FREE_BATCH       4
 181
 182 static void free_obj_work(struct work_struct *work)
 183 {
 184         struct debug_obj *objs[ODEBUG_FREE_BATCH];
 185         unsigned long flags;
 186         int i;
 187
 188         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 189                 return;
 190         while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) {
 191                 for (i = 0; i < ODEBUG_FREE_BATCH; i++) {
 192                         objs[i] = hlist_entry(obj_pool.first,
 193                                               typeof(*objs[0]), node);
 194                         hlist_del(&objs[i]->node);
 195                 }
 196
 197                 obj_pool_free -= ODEBUG_FREE_BATCH;
 198                 debug_objects_freed += ODEBUG_FREE_BATCH;
 199                 /*
 200                  * We release pool_lock across kmem_cache_free() to
 201                  * avoid contention on pool_lock.
 202                  */
 203                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 204                 for (i = 0; i < ODEBUG_FREE_BATCH; i++)
 205                         kmem_cache_free(obj_cache, objs[i]);
 206                 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 207                         return;
 208         }
 209         raw_spin_unlock_irqrestore(&pool_lock, flags);
 210 }
 211
 212 /*
 213  * Put the object back into the pool and schedule work to free objects
 214  * if necessary.
 215  */
 216 static void free_object(struct debug_obj *obj)
 217 {
 218         unsigned long flags;
 219         int sched = 0;
 220
 221         raw_spin_lock_irqsave(&pool_lock, flags);
 222         /*
 223          * schedule work when the pool is filled and the cache is
 224          * initialized:
 225          */
 226         if (obj_pool_free > debug_objects_pool_size && obj_cache)
 227                 sched = 1;
 228         hlist_add_head(&obj->node, &obj_pool);
 229         obj_pool_free++;
 230         obj_pool_used--;
 231         raw_spin_unlock_irqrestore(&pool_lock, flags);
 232         if (sched)
 233                 schedule_work(&debug_obj_work);
 234 }
 235
 236 /*
 237  * We run out of memory. That means we probably have tons of objects
 238  * allocated.
 239  */
 240 static void debug_objects_oom(void)
 241 {
 242         struct debug_bucket *db = obj_hash;
 243         struct hlist_node *tmp;
 244         HLIST_HEAD(freelist);
 245         struct debug_obj *obj;
 246         unsigned long flags;
 247         int i;
 248
 249         pr_warn("Out of memory. ODEBUG disabled\n");
 250
 251         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 252                 raw_spin_lock_irqsave(&db->lock, flags);
 253                 hlist_move_list(&db->list, &freelist);
 254                 raw_spin_unlock_irqrestore(&db->lock, flags);
 255
 256                 /* Now free them */
 257                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 258                         hlist_del(&obj->node);
 259                         free_object(obj);
 260                 }
 261         }
 262 }
 263
 264 /*
 265  * We use the pfn of the address for the hash. That way we can check
 266  * for freed objects simply by checking the affected bucket.
 267  */
 268 static struct debug_bucket *get_bucket(unsigned long addr)
 269 {
 270         unsigned long hash;
 271
 272         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 273         return &obj_hash[hash];
 274 }
 275
 276 static void debug_print_object(struct debug_obj *obj, char *msg)
 277 {
 278         struct debug_obj_descr *descr = obj->descr;
 279         static int limit;
 280
 281         if (limit < 5 && descr != descr_test) {
 282                 void *hint = descr->debug_hint ?
 283                         descr->debug_hint(obj->object) : NULL;
 284                 limit++;
 285                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 286                                  "object type: %s hint: %pS\n",
 287                         msg, obj_states[obj->state], obj->astate,
 288                         descr->name, hint);
 289         }
 290         debug_objects_warnings++;
 291 }
 292
 293 /*
 294  * Try to repair the damage, so we have a better chance to get useful
 295  * debug output.
 296  */
 297 static bool
 298 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 299                    void * addr, enum debug_obj_state state)
 300 {
 301         if (fixup && fixup(addr, state)) {
 302                 debug_objects_fixups++;
 303                 return true;
 304         }
 305         return false;
 306 }
 307
 308 static void debug_object_is_on_stack(void *addr, int onstack)
 309 {
 310         int is_on_stack;
 311         static int limit;
 312
 313         if (limit > 4)
 314                 return;
 315
 316         is_on_stack = object_is_on_stack(addr);
 317         if (is_on_stack == onstack)
 318                 return;
 319
 320         limit++;
 321         if (is_on_stack)
 322                 pr_warn("object is on stack, but not annotated\n");
 323         else
 324                 pr_warn("object is not on stack, but annotated\n");
 325         WARN_ON(1);
 326 }
 327
 328 static void
 329 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 330 {
 331         enum debug_obj_state state;
 332         struct debug_bucket *db;
 333         struct debug_obj *obj;
 334         unsigned long flags;
 335
 336         fill_pool();
 337
 338         db = get_bucket((unsigned long) addr);
 339
 340         raw_spin_lock_irqsave(&db->lock, flags);
 341
 342         obj = lookup_object(addr, db);
 343         if (!obj) {
 344                 obj = alloc_object(addr, db, descr);
 345                 if (!obj) {
 346                         debug_objects_enabled = 0;
 347                         raw_spin_unlock_irqrestore(&db->lock, flags);
 348                         debug_objects_oom();
 349                         return;
 350                 }
 351                 debug_object_is_on_stack(addr, onstack);
 352         }
 353
 354         switch (obj->state) {
 355         case ODEBUG_STATE_NONE:
 356         case ODEBUG_STATE_INIT:
 357         case ODEBUG_STATE_INACTIVE:
 358                 obj->state = ODEBUG_STATE_INIT;
 359                 break;
 360
 361         case ODEBUG_STATE_ACTIVE:
 362                 debug_print_object(obj, "init");
 363                 state = obj->state;
 364                 raw_spin_unlock_irqrestore(&db->lock, flags);
 365                 debug_object_fixup(descr->fixup_init, addr, state);
 366                 return;
 367
 368         case ODEBUG_STATE_DESTROYED:
 369                 debug_print_object(obj, "init");
 370                 break;
 371         default:
 372                 break;
 373         }
 374
 375         raw_spin_unlock_irqrestore(&db->lock, flags);
 376 }
 377
 378 /**
 379  * debug_object_init - debug checks when an object is initialized
 380  * @addr:       address of the object
 381  * @descr:      pointer to an object specific debug description structure
 382  */
 383 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 384 {
 385         if (!debug_objects_enabled)
 386                 return;
 387
 388         __debug_object_init(addr, descr, 0);
 389 }
 390 EXPORT_SYMBOL_GPL(debug_object_init);
 391
 392 /**
 393  * debug_object_init_on_stack - debug checks when an object on stack is
 394  *                              initialized
 395  * @addr:       address of the object
 396  * @descr:      pointer to an object specific debug description structure
 397  */
 398 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 399 {
 400         if (!debug_objects_enabled)
 401                 return;
 402
 403         __debug_object_init(addr, descr, 1);
 404 }
 405 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 406
 407 /**
 408  * debug_object_activate - debug checks when an object is activated
 409  * @addr:       address of the object
 410  * @descr:      pointer to an object specific debug description structure
 411  * Returns 0 for success, -EINVAL for check failed.
 412  */
 413 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 414 {
 415         enum debug_obj_state state;
 416         struct debug_bucket *db;
 417         struct debug_obj *obj;
 418         unsigned long flags;
 419         int ret;
 420         struct debug_obj o = { .object = addr,
 421                                .state = ODEBUG_STATE_NOTAVAILABLE,
 422                                .descr = descr };
 423
 424         if (!debug_objects_enabled)
 425                 return 0;
 426
 427         db = get_bucket((unsigned long) addr);
 428
 429         raw_spin_lock_irqsave(&db->lock, flags);
 430
 431         obj = lookup_object(addr, db);
 432         if (obj) {
 433                 switch (obj->state) {
 434                 case ODEBUG_STATE_INIT:
 435                 case ODEBUG_STATE_INACTIVE:
 436                         obj->state = ODEBUG_STATE_ACTIVE;
 437                         ret = 0;
 438                         break;
 439
 440                 case ODEBUG_STATE_ACTIVE:
 441                         debug_print_object(obj, "activate");
 442                         state = obj->state;
 443                         raw_spin_unlock_irqrestore(&db->lock, flags);
 444                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 445                         return ret ? 0 : -EINVAL;
 446
 447                 case ODEBUG_STATE_DESTROYED:
 448                         debug_print_object(obj, "activate");
 449                         ret = -EINVAL;
 450                         break;
 451                 default:
 452                         ret = 0;
 453                         break;
 454                 }
 455                 raw_spin_unlock_irqrestore(&db->lock, flags);
 456                 return ret;
 457         }
 458
 459         raw_spin_unlock_irqrestore(&db->lock, flags);
 460         /*
 461          * We are here when a static object is activated. We
 462          * let the type specific code confirm whether this is
 463          * true or not. if true, we just make sure that the
 464          * static object is tracked in the object tracker. If
 465          * not, this must be a bug, so we try to fix it up.
 466          */
 467         if (descr->is_static_object && descr->is_static_object(addr)) {
 468                 /* track this static object */
 469                 debug_object_init(addr, descr);
 470                 debug_object_activate(addr, descr);
 471         } else {
 472                 debug_print_object(&o, "activate");
 473                 ret = debug_object_fixup(descr->fixup_activate, addr,
 474                                         ODEBUG_STATE_NOTAVAILABLE);
 475                 return ret ? 0 : -EINVAL;
 476         }
 477         return 0;
 478 }
 479 EXPORT_SYMBOL_GPL(debug_object_activate);
 480
 481 /**
 482  * debug_object_deactivate - debug checks when an object is deactivated
 483  * @addr:       address of the object
 484  * @descr:      pointer to an object specific debug description structure
 485  */
 486 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 487 {
 488         struct debug_bucket *db;
 489         struct debug_obj *obj;
 490         unsigned long flags;
 491
 492         if (!debug_objects_enabled)
 493                 return;
 494
 495         db = get_bucket((unsigned long) addr);
 496
 497         raw_spin_lock_irqsave(&db->lock, flags);
 498
 499         obj = lookup_object(addr, db);
 500         if (obj) {
 501                 switch (obj->state) {
 502                 case ODEBUG_STATE_INIT:
 503                 case ODEBUG_STATE_INACTIVE:
 504                 case ODEBUG_STATE_ACTIVE:
 505                         if (!obj->astate)
 506                                 obj->state = ODEBUG_STATE_INACTIVE;
 507                         else
 508                                 debug_print_object(obj, "deactivate");
 509                         break;
 510
 511                 case ODEBUG_STATE_DESTROYED:
 512                         debug_print_object(obj, "deactivate");
 513                         break;
 514                 default:
 515                         break;
 516                 }
 517         } else {
 518                 struct debug_obj o = { .object = addr,
 519                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 520                                        .descr = descr };
 521
 522                 debug_print_object(&o, "deactivate");
 523         }
 524
 525         raw_spin_unlock_irqrestore(&db->lock, flags);
 526 }
 527 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 528
 529 /**
 530  * debug_object_destroy - debug checks when an object is destroyed
 531  * @addr:       address of the object
 532  * @descr:      pointer to an object specific debug description structure
 533  */
 534 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 535 {
 536         enum debug_obj_state state;
 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                 goto out_unlock;
 551
 552         switch (obj->state) {
 553         case ODEBUG_STATE_NONE:
 554         case ODEBUG_STATE_INIT:
 555         case ODEBUG_STATE_INACTIVE:
 556                 obj->state = ODEBUG_STATE_DESTROYED;
 557                 break;
 558         case ODEBUG_STATE_ACTIVE:
 559                 debug_print_object(obj, "destroy");
 560                 state = obj->state;
 561                 raw_spin_unlock_irqrestore(&db->lock, flags);
 562                 debug_object_fixup(descr->fixup_destroy, addr, state);
 563                 return;
 564
 565         case ODEBUG_STATE_DESTROYED:
 566                 debug_print_object(obj, "destroy");
 567                 break;
 568         default:
 569                 break;
 570         }
 571 out_unlock:
 572         raw_spin_unlock_irqrestore(&db->lock, flags);
 573 }
 574 EXPORT_SYMBOL_GPL(debug_object_destroy);
 575
 576 /**
 577  * debug_object_free - debug checks when an object is freed
 578  * @addr:       address of the object
 579  * @descr:      pointer to an object specific debug description structure
 580  */
 581 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 582 {
 583         enum debug_obj_state state;
 584         struct debug_bucket *db;
 585         struct debug_obj *obj;
 586         unsigned long flags;
 587
 588         if (!debug_objects_enabled)
 589                 return;
 590
 591         db = get_bucket((unsigned long) addr);
 592
 593         raw_spin_lock_irqsave(&db->lock, flags);
 594
 595         obj = lookup_object(addr, db);
 596         if (!obj)
 597                 goto out_unlock;
 598
 599         switch (obj->state) {
 600         case ODEBUG_STATE_ACTIVE:
 601                 debug_print_object(obj, "free");
 602                 state = obj->state;
 603                 raw_spin_unlock_irqrestore(&db->lock, flags);
 604                 debug_object_fixup(descr->fixup_free, addr, state);
 605                 return;
 606         default:
 607                 hlist_del(&obj->node);
 608                 raw_spin_unlock_irqrestore(&db->lock, flags);
 609                 free_object(obj);
 610                 return;
 611         }
 612 out_unlock:
 613         raw_spin_unlock_irqrestore(&db->lock, flags);
 614 }
 615 EXPORT_SYMBOL_GPL(debug_object_free);
 616
 617 /**
 618  * debug_object_assert_init - debug checks when object should be init-ed
 619  * @addr:       address of the object
 620  * @descr:      pointer to an object specific debug description structure
 621  */
 622 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 623 {
 624         struct debug_bucket *db;
 625         struct debug_obj *obj;
 626         unsigned long flags;
 627
 628         if (!debug_objects_enabled)
 629                 return;
 630
 631         db = get_bucket((unsigned long) addr);
 632
 633         raw_spin_lock_irqsave(&db->lock, flags);
 634
 635         obj = lookup_object(addr, db);
 636         if (!obj) {
 637                 struct debug_obj o = { .object = addr,
 638                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 639                                        .descr = descr };
 640
 641                 raw_spin_unlock_irqrestore(&db->lock, flags);
 642                 /*
 643                  * Maybe the object is static, and we let the type specific
 644                  * code confirm. Track this static object if true, else invoke
 645                  * fixup.
 646                  */
 647                 if (descr->is_static_object && descr->is_static_object(addr)) {
 648                         /* Track this static object */
 649                         debug_object_init(addr, descr);
 650                 } else {
 651                         debug_print_object(&o, "assert_init");
 652                         debug_object_fixup(descr->fixup_assert_init, addr,
 653                                            ODEBUG_STATE_NOTAVAILABLE);
 654                 }
 655                 return;
 656         }
 657
 658         raw_spin_unlock_irqrestore(&db->lock, flags);
 659 }
 660 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 661
 662 /**
 663  * debug_object_active_state - debug checks object usage state machine
 664  * @addr:       address of the object
 665  * @descr:      pointer to an object specific debug description structure
 666  * @expect:     expected state
 667  * @next:       state to move to if expected state is found
 668  */
 669 void
 670 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 671                           unsigned int expect, unsigned int next)
 672 {
 673         struct debug_bucket *db;
 674         struct debug_obj *obj;
 675         unsigned long flags;
 676
 677         if (!debug_objects_enabled)
 678                 return;
 679
 680         db = get_bucket((unsigned long) addr);
 681
 682         raw_spin_lock_irqsave(&db->lock, flags);
 683
 684         obj = lookup_object(addr, db);
 685         if (obj) {
 686                 switch (obj->state) {
 687                 case ODEBUG_STATE_ACTIVE:
 688                         if (obj->astate == expect)
 689                                 obj->astate = next;
 690                         else
 691                                 debug_print_object(obj, "active_state");
 692                         break;
 693
 694                 default:
 695                         debug_print_object(obj, "active_state");
 696                         break;
 697                 }
 698         } else {
 699                 struct debug_obj o = { .object = addr,
 700                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 701                                        .descr = descr };
 702
 703                 debug_print_object(&o, "active_state");
 704         }
 705
 706         raw_spin_unlock_irqrestore(&db->lock, flags);
 707 }
 708 EXPORT_SYMBOL_GPL(debug_object_active_state);
 709
 710 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 711 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 712 {
 713         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 714         struct hlist_node *tmp;
 715         HLIST_HEAD(freelist);
 716         struct debug_obj_descr *descr;
 717         enum debug_obj_state state;
 718         struct debug_bucket *db;
 719         struct debug_obj *obj;
 720         int cnt;
 721
 722         saddr = (unsigned long) address;
 723         eaddr = saddr + size;
 724         paddr = saddr & ODEBUG_CHUNK_MASK;
 725         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 726         chunks >>= ODEBUG_CHUNK_SHIFT;
 727
 728         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 729                 db = get_bucket(paddr);
 730
 731 repeat:
 732                 cnt = 0;
 733                 raw_spin_lock_irqsave(&db->lock, flags);
 734                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 735                         cnt++;
 736                         oaddr = (unsigned long) obj->object;
 737                         if (oaddr < saddr || oaddr >= eaddr)
 738                                 continue;
 739
 740                         switch (obj->state) {
 741                         case ODEBUG_STATE_ACTIVE:
 742                                 debug_print_object(obj, "free");
 743                                 descr = obj->descr;
 744                                 state = obj->state;
 745                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 746                                 debug_object_fixup(descr->fixup_free,
 747                                                    (void *) oaddr, state);
 748                                 goto repeat;
 749                         default:
 750                                 hlist_del(&obj->node);
 751                                 hlist_add_head(&obj->node, &freelist);
 752                                 break;
 753                         }
 754                 }
 755                 raw_spin_unlock_irqrestore(&db->lock, flags);
 756
 757                 /* Now free them */
 758                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 759                         hlist_del(&obj->node);
 760                         free_object(obj);
 761                 }
 762
 763                 if (cnt > debug_objects_maxchain)
 764                         debug_objects_maxchain = cnt;
 765         }
 766 }
 767
 768 void debug_check_no_obj_freed(const void *address, unsigned long size)
 769 {
 770         if (debug_objects_enabled)
 771                 __debug_check_no_obj_freed(address, size);
 772 }
 773 #endif
 774
 775 #ifdef CONFIG_DEBUG_FS
 776
 777 static int debug_stats_show(struct seq_file *m, void *v)
 778 {
 779         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 780         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 781         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 782         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 783         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 784         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 785         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 786         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 787         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 788         return 0;
 789 }
 790
 791 static int debug_stats_open(struct inode *inode, struct file *filp)
 792 {
 793         return single_open(filp, debug_stats_show, NULL);
 794 }
 795
 796 static const struct file_operations debug_stats_fops = {
 797         .open           = debug_stats_open,
 798         .read           = seq_read,
 799         .llseek         = seq_lseek,
 800         .release        = single_release,
 801 };
 802
 803 static int __init debug_objects_init_debugfs(void)
 804 {
 805         struct dentry *dbgdir, *dbgstats;
 806
 807         if (!debug_objects_enabled)
 808                 return 0;
 809
 810         dbgdir = debugfs_create_dir("debug_objects", NULL);
 811         if (!dbgdir)
 812                 return -ENOMEM;
 813
 814         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 815                                        &debug_stats_fops);
 816         if (!dbgstats)
 817                 goto err;
 818
 819         return 0;
 820
 821 err:
 822         debugfs_remove(dbgdir);
 823
 824         return -ENOMEM;
 825 }
 826 __initcall(debug_objects_init_debugfs);
 827
 828 #else
 829 static inline void debug_objects_init_debugfs(void) { }
 830 #endif
 831
 832 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 833
 834 /* Random data structure for the self test */
 835 struct self_test {
 836         unsigned long   dummy1[6];
 837         int             static_init;
 838         unsigned long   dummy2[3];
 839 };
 840
 841 static __initdata struct debug_obj_descr descr_type_test;
 842
 843 static bool __init is_static_object(void *addr)
 844 {
 845         struct self_test *obj = addr;
 846
 847         return obj->static_init;
 848 }
 849
 850 /*
 851  * fixup_init is called when:
 852  * - an active object is initialized
 853  */
 854 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 855 {
 856         struct self_test *obj = addr;
 857
 858         switch (state) {
 859         case ODEBUG_STATE_ACTIVE:
 860                 debug_object_deactivate(obj, &descr_type_test);
 861                 debug_object_init(obj, &descr_type_test);
 862                 return true;
 863         default:
 864                 return false;
 865         }
 866 }
 867
 868 /*
 869  * fixup_activate is called when:
 870  * - an active object is activated
 871  * - an unknown non-static object is activated
 872  */
 873 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 874 {
 875         struct self_test *obj = addr;
 876
 877         switch (state) {
 878         case ODEBUG_STATE_NOTAVAILABLE:
 879                 return true;
 880         case ODEBUG_STATE_ACTIVE:
 881                 debug_object_deactivate(obj, &descr_type_test);
 882                 debug_object_activate(obj, &descr_type_test);
 883                 return true;
 884
 885         default:
 886                 return false;
 887         }
 888 }
 889
 890 /*
 891  * fixup_destroy is called when:
 892  * - an active object is destroyed
 893  */
 894 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 895 {
 896         struct self_test *obj = addr;
 897
 898         switch (state) {
 899         case ODEBUG_STATE_ACTIVE:
 900                 debug_object_deactivate(obj, &descr_type_test);
 901                 debug_object_destroy(obj, &descr_type_test);
 902                 return true;
 903         default:
 904                 return false;
 905         }
 906 }
 907
 908 /*
 909  * fixup_free is called when:
 910  * - an active object is freed
 911  */
 912 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 913 {
 914         struct self_test *obj = addr;
 915
 916         switch (state) {
 917         case ODEBUG_STATE_ACTIVE:
 918                 debug_object_deactivate(obj, &descr_type_test);
 919                 debug_object_free(obj, &descr_type_test);
 920                 return true;
 921         default:
 922                 return false;
 923         }
 924 }
 925
 926 static int __init
 927 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 928 {
 929         struct debug_bucket *db;
 930         struct debug_obj *obj;
 931         unsigned long flags;
 932         int res = -EINVAL;
 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 && state != ODEBUG_STATE_NONE) {
 940                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 941                 goto out;
 942         }
 943         if (obj && obj->state != state) {
 944                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 945                        obj->state, state);
 946                 goto out;
 947         }
 948         if (fixups != debug_objects_fixups) {
 949                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 950                        fixups, debug_objects_fixups);
 951                 goto out;
 952         }
 953         if (warnings != debug_objects_warnings) {
 954                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 955                        warnings, debug_objects_warnings);
 956                 goto out;
 957         }
 958         res = 0;
 959 out:
 960         raw_spin_unlock_irqrestore(&db->lock, flags);
 961         if (res)
 962                 debug_objects_enabled = 0;
 963         return res;
 964 }
 965
 966 static __initdata struct debug_obj_descr descr_type_test = {
 967         .name                   = "selftest",
 968         .is_static_object       = is_static_object,
 969         .fixup_init             = fixup_init,
 970         .fixup_activate         = fixup_activate,
 971         .fixup_destroy          = fixup_destroy,
 972         .fixup_free             = fixup_free,
 973 };
 974
 975 static __initdata struct self_test obj = { .static_init = 0 };
 976
 977 static void __init debug_objects_selftest(void)
 978 {
 979         int fixups, oldfixups, warnings, oldwarnings;
 980         unsigned long flags;
 981
 982         local_irq_save(flags);
 983
 984         fixups = oldfixups = debug_objects_fixups;
 985         warnings = oldwarnings = debug_objects_warnings;
 986         descr_test = &descr_type_test;
 987
 988         debug_object_init(&obj, &descr_type_test);
 989         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 990                 goto out;
 991         debug_object_activate(&obj, &descr_type_test);
 992         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 993                 goto out;
 994         debug_object_activate(&obj, &descr_type_test);
 995         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 996                 goto out;
 997         debug_object_deactivate(&obj, &descr_type_test);
 998         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 999                 goto out;
1000         debug_object_destroy(&obj, &descr_type_test);
1001         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1002                 goto out;
1003         debug_object_init(&obj, &descr_type_test);
1004         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1005                 goto out;
1006         debug_object_activate(&obj, &descr_type_test);
1007         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1008                 goto out;
1009         debug_object_deactivate(&obj, &descr_type_test);
1010         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1011                 goto out;
1012         debug_object_free(&obj, &descr_type_test);
1013         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1014                 goto out;
1015
1016         obj.static_init = 1;
1017         debug_object_activate(&obj, &descr_type_test);
1018         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1019                 goto out;
1020         debug_object_init(&obj, &descr_type_test);
1021         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1022                 goto out;
1023         debug_object_free(&obj, &descr_type_test);
1024         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1025                 goto out;
1026
1027 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1028         debug_object_init(&obj, &descr_type_test);
1029         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1030                 goto out;
1031         debug_object_activate(&obj, &descr_type_test);
1032         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1033                 goto out;
1034         __debug_check_no_obj_freed(&obj, sizeof(obj));
1035         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1036                 goto out;
1037 #endif
1038         pr_info("selftest passed\n");
1039
1040 out:
1041         debug_objects_fixups = oldfixups;
1042         debug_objects_warnings = oldwarnings;
1043         descr_test = NULL;
1044
1045         local_irq_restore(flags);
1046 }
1047 #else
1048 static inline void debug_objects_selftest(void) { }
1049 #endif
1050
1051 /*
1052  * Called during early boot to initialize the hash buckets and link
1053  * the static object pool objects into the poll list. After this call
1054  * the object tracker is fully operational.
1055  */
1056 void __init debug_objects_early_init(void)
1057 {
1058         int i;
1059
1060         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1061                 raw_spin_lock_init(&obj_hash[i].lock);
1062
1063         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1064                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1065 }
1066
1067 /*
1068  * Convert the statically allocated objects to dynamic ones:
1069  */
1070 static int __init debug_objects_replace_static_objects(void)
1071 {
1072         struct debug_bucket *db = obj_hash;
1073         struct hlist_node *tmp;
1074         struct debug_obj *obj, *new;
1075         HLIST_HEAD(objects);
1076         int i, cnt = 0;
1077
1078         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1079                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1080                 if (!obj)
1081                         goto free;
1082                 hlist_add_head(&obj->node, &objects);
1083         }
1084
1085         /*
1086          * When debug_objects_mem_init() is called we know that only
1087          * one CPU is up, so disabling interrupts is enough
1088          * protection. This avoids the lockdep hell of lock ordering.
1089          */
1090         local_irq_disable();
1091
1092         /* Remove the statically allocated objects from the pool */
1093         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1094                 hlist_del(&obj->node);
1095         /* Move the allocated objects to the pool */
1096         hlist_move_list(&objects, &obj_pool);
1097
1098         /* Replace the active object references */
1099         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1100                 hlist_move_list(&db->list, &objects);
1101
1102                 hlist_for_each_entry(obj, &objects, node) {
1103                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1104                         hlist_del(&new->node);
1105                         /* copy object data */
1106                         *new = *obj;
1107                         hlist_add_head(&new->node, &db->list);
1108                         cnt++;
1109                 }
1110         }
1111         local_irq_enable();
1112
1113         pr_debug("%d of %d active objects replaced\n",
1114                  cnt, obj_pool_used);
1115         return 0;
1116 free:
1117         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1118                 hlist_del(&obj->node);
1119                 kmem_cache_free(obj_cache, obj);
1120         }
1121         return -ENOMEM;
1122 }
1123
1124 /*
1125  * Called after the kmem_caches are functional to setup a dedicated
1126  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1127  * prevents that the debug code is called on kmem_cache_free() for the
1128  * debug tracker objects to avoid recursive calls.
1129  */
1130 void __init debug_objects_mem_init(void)
1131 {
1132         if (!debug_objects_enabled)
1133                 return;
1134
1135         obj_cache = kmem_cache_create("debug_objects_cache",
1136                                       sizeof (struct debug_obj), 0,
1137                                       SLAB_DEBUG_OBJECTS, NULL);
1138
1139         if (!obj_cache || debug_objects_replace_static_objects()) {
1140                 debug_objects_enabled = 0;
1141                 if (obj_cache)
1142                         kmem_cache_destroy(obj_cache);
1143                 pr_warn("out of memory.\n");
1144         } else
1145                 debug_objects_selftest();
1146
1147         /*
1148          * Increase the thresholds for allocating and freeing objects
1149          * according to the number of possible CPUs available in the system.
1150          */
1151         debug_objects_pool_size += num_possible_cpus() * 32;
1152         debug_objects_pool_min_level += num_possible_cpus() * 4;
1153 }