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
  22 #define ODEBUG_HASH_BITS        14
  23 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  24
  25 #define ODEBUG_POOL_SIZE        1024
  26 #define ODEBUG_POOL_MIN_LEVEL   256
  27
  28 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  29 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  30 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  31
  32 struct debug_bucket {
  33         struct hlist_head       list;
  34         raw_spinlock_t          lock;
  35 };
  36
  37 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  38
  39 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  40
  41 static DEFINE_RAW_SPINLOCK(pool_lock);
  42
  43 static HLIST_HEAD(obj_pool);
  44
  45 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  46 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  47 static int                      obj_pool_used;
  48 static int                      obj_pool_max_used;
  49 static struct kmem_cache        *obj_cache;
  50
  51 static int                      debug_objects_maxchain __read_mostly;
  52 static int                      debug_objects_fixups __read_mostly;
  53 static int                      debug_objects_warnings __read_mostly;
  54 static int                      debug_objects_enabled __read_mostly
  55                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  56 static int                      debug_objects_pool_size __read_mostly
  57                                 = ODEBUG_POOL_SIZE;
  58 static int                      debug_objects_pool_min_level __read_mostly
  59                                 = ODEBUG_POOL_MIN_LEVEL;
  60 static struct debug_obj_descr   *descr_test  __read_mostly;
  61
  62 /*
  63  * Track numbers of kmem_cache_alloc()/free() calls done.
  64  */
  65 static int                      debug_objects_allocated;
  66 static int                      debug_objects_freed;
  67
  68 static void free_obj_work(struct work_struct *work);
  69 static DECLARE_WORK(debug_obj_work, free_obj_work);
  70
  71 static int __init enable_object_debug(char *str)
  72 {
  73         debug_objects_enabled = 1;
  74         return 0;
  75 }
  76
  77 static int __init disable_object_debug(char *str)
  78 {
  79         debug_objects_enabled = 0;
  80         return 0;
  81 }
  82
  83 early_param("debug_objects", enable_object_debug);
  84 early_param("no_debug_objects", disable_object_debug);
  85
  86 static const char *obj_states[ODEBUG_STATE_MAX] = {
  87         [ODEBUG_STATE_NONE]             = "none",
  88         [ODEBUG_STATE_INIT]             = "initialized",
  89         [ODEBUG_STATE_INACTIVE]         = "inactive",
  90         [ODEBUG_STATE_ACTIVE]           = "active",
  91         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  92         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  93 };
  94
  95 static void fill_pool(void)
  96 {
  97         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  98         struct debug_obj *new;
  99         unsigned long flags;
 100
 101         if (likely(obj_pool_free >= debug_objects_pool_min_level))
 102                 return;
 103
 104         if (unlikely(!obj_cache))
 105                 return;
 106
 107         while (obj_pool_free < debug_objects_pool_min_level) {
 108
 109                 new = kmem_cache_zalloc(obj_cache, gfp);
 110                 if (!new)
 111                         return;
 112
 113                 raw_spin_lock_irqsave(&pool_lock, flags);
 114                 hlist_add_head(&new->node, &obj_pool);
 115                 debug_objects_allocated++;
 116                 obj_pool_free++;
 117                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 118         }
 119 }
 120
 121 /*
 122  * Lookup an object in the hash bucket.
 123  */
 124 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 125 {
 126         struct debug_obj *obj;
 127         int cnt = 0;
 128
 129         hlist_for_each_entry(obj, &b->list, node) {
 130                 cnt++;
 131                 if (obj->object == addr)
 132                         return obj;
 133         }
 134         if (cnt > debug_objects_maxchain)
 135                 debug_objects_maxchain = cnt;
 136
 137         return NULL;
 138 }
 139
 140 /*
 141  * Allocate a new object. If the pool is empty, switch off the debugger.
 142  * Must be called with interrupts disabled.
 143  */
 144 static struct debug_obj *
 145 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 146 {
 147         struct debug_obj *obj = NULL;
 148
 149         raw_spin_lock(&pool_lock);
 150         if (obj_pool.first) {
 151                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 152
 153                 obj->object = addr;
 154                 obj->descr  = descr;
 155                 obj->state  = ODEBUG_STATE_NONE;
 156                 obj->astate = 0;
 157                 hlist_del(&obj->node);
 158
 159                 hlist_add_head(&obj->node, &b->list);
 160
 161                 obj_pool_used++;
 162                 if (obj_pool_used > obj_pool_max_used)
 163                         obj_pool_max_used = obj_pool_used;
 164
 165                 obj_pool_free--;
 166                 if (obj_pool_free < obj_pool_min_free)
 167                         obj_pool_min_free = obj_pool_free;
 168         }
 169         raw_spin_unlock(&pool_lock);
 170
 171         return obj;
 172 }
 173
 174 /*
 175  * workqueue function to free objects.
 176  *
 177  * To reduce contention on the global pool_lock, the actual freeing of
 178  * debug objects will be delayed if the pool_lock is busy. We also free
 179  * the objects in a batch of 4 for each lock/unlock cycle.
 180  */
 181 #define ODEBUG_FREE_BATCH       4
 182
 183 static void free_obj_work(struct work_struct *work)
 184 {
 185         struct debug_obj *objs[ODEBUG_FREE_BATCH];
 186         unsigned long flags;
 187         int i;
 188
 189         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 190                 return;
 191         while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) {
 192                 for (i = 0; i < ODEBUG_FREE_BATCH; i++) {
 193                         objs[i] = hlist_entry(obj_pool.first,
 194                                               typeof(*objs[0]), node);
 195                         hlist_del(&objs[i]->node);
 196                 }
 197
 198                 obj_pool_free -= ODEBUG_FREE_BATCH;
 199                 debug_objects_freed += ODEBUG_FREE_BATCH;
 200                 /*
 201                  * We release pool_lock across kmem_cache_free() to
 202                  * avoid contention on pool_lock.
 203                  */
 204                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 205                 for (i = 0; i < ODEBUG_FREE_BATCH; i++)
 206                         kmem_cache_free(obj_cache, objs[i]);
 207                 if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 208                         return;
 209         }
 210         raw_spin_unlock_irqrestore(&pool_lock, flags);
 211 }
 212
 213 /*
 214  * Put the object back into the pool and schedule work to free objects
 215  * if necessary.
 216  */
 217 static void free_object(struct debug_obj *obj)
 218 {
 219         unsigned long flags;
 220         int sched = 0;
 221
 222         raw_spin_lock_irqsave(&pool_lock, flags);
 223         /*
 224          * schedule work when the pool is filled and the cache is
 225          * initialized:
 226          */
 227         if (obj_pool_free > debug_objects_pool_size && obj_cache)
 228                 sched = 1;
 229         hlist_add_head(&obj->node, &obj_pool);
 230         obj_pool_free++;
 231         obj_pool_used--;
 232         raw_spin_unlock_irqrestore(&pool_lock, flags);
 233         if (sched)
 234                 schedule_work(&debug_obj_work);
 235 }
 236
 237 /*
 238  * We run out of memory. That means we probably have tons of objects
 239  * allocated.
 240  */
 241 static void debug_objects_oom(void)
 242 {
 243         struct debug_bucket *db = obj_hash;
 244         struct hlist_node *tmp;
 245         HLIST_HEAD(freelist);
 246         struct debug_obj *obj;
 247         unsigned long flags;
 248         int i;
 249
 250         pr_warn("Out of memory. ODEBUG disabled\n");
 251
 252         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 253                 raw_spin_lock_irqsave(&db->lock, flags);
 254                 hlist_move_list(&db->list, &freelist);
 255                 raw_spin_unlock_irqrestore(&db->lock, flags);
 256
 257                 /* Now free them */
 258                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 259                         hlist_del(&obj->node);
 260                         free_object(obj);
 261                 }
 262         }
 263 }
 264
 265 /*
 266  * We use the pfn of the address for the hash. That way we can check
 267  * for freed objects simply by checking the affected bucket.
 268  */
 269 static struct debug_bucket *get_bucket(unsigned long addr)
 270 {
 271         unsigned long hash;
 272
 273         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 274         return &obj_hash[hash];
 275 }
 276
 277 static void debug_print_object(struct debug_obj *obj, char *msg)
 278 {
 279         struct debug_obj_descr *descr = obj->descr;
 280         static int limit;
 281
 282         if (limit < 5 && descr != descr_test) {
 283                 void *hint = descr->debug_hint ?
 284                         descr->debug_hint(obj->object) : NULL;
 285                 limit++;
 286                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 287                                  "object type: %s hint: %pS\n",
 288                         msg, obj_states[obj->state], obj->astate,
 289                         descr->name, hint);
 290         }
 291         debug_objects_warnings++;
 292 }
 293
 294 /*
 295  * Try to repair the damage, so we have a better chance to get useful
 296  * debug output.
 297  */
 298 static bool
 299 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 300                    void * addr, enum debug_obj_state state)
 301 {
 302         if (fixup && fixup(addr, state)) {
 303                 debug_objects_fixups++;
 304                 return true;
 305         }
 306         return false;
 307 }
 308
 309 static void debug_object_is_on_stack(void *addr, int onstack)
 310 {
 311         int is_on_stack;
 312         static int limit;
 313
 314         if (limit > 4)
 315                 return;
 316
 317         is_on_stack = object_is_on_stack(addr);
 318         if (is_on_stack == onstack)
 319                 return;
 320
 321         limit++;
 322         if (is_on_stack)
 323                 pr_warn("object is on stack, but not annotated\n");
 324         else
 325                 pr_warn("object is not on stack, but annotated\n");
 326         WARN_ON(1);
 327 }
 328
 329 static void
 330 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 331 {
 332         enum debug_obj_state state;
 333         struct debug_bucket *db;
 334         struct debug_obj *obj;
 335         unsigned long flags;
 336
 337         fill_pool();
 338
 339         db = get_bucket((unsigned long) addr);
 340
 341         raw_spin_lock_irqsave(&db->lock, flags);
 342
 343         obj = lookup_object(addr, db);
 344         if (!obj) {
 345                 obj = alloc_object(addr, db, descr);
 346                 if (!obj) {
 347                         debug_objects_enabled = 0;
 348                         raw_spin_unlock_irqrestore(&db->lock, flags);
 349                         debug_objects_oom();
 350                         return;
 351                 }
 352                 debug_object_is_on_stack(addr, onstack);
 353         }
 354
 355         switch (obj->state) {
 356         case ODEBUG_STATE_NONE:
 357         case ODEBUG_STATE_INIT:
 358         case ODEBUG_STATE_INACTIVE:
 359                 obj->state = ODEBUG_STATE_INIT;
 360                 break;
 361
 362         case ODEBUG_STATE_ACTIVE:
 363                 debug_print_object(obj, "init");
 364                 state = obj->state;
 365                 raw_spin_unlock_irqrestore(&db->lock, flags);
 366                 debug_object_fixup(descr->fixup_init, addr, state);
 367                 return;
 368
 369         case ODEBUG_STATE_DESTROYED:
 370                 debug_print_object(obj, "init");
 371                 break;
 372         default:
 373                 break;
 374         }
 375
 376         raw_spin_unlock_irqrestore(&db->lock, flags);
 377 }
 378
 379 /**
 380  * debug_object_init - debug checks when an object is initialized
 381  * @addr:       address of the object
 382  * @descr:      pointer to an object specific debug description structure
 383  */
 384 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 385 {
 386         if (!debug_objects_enabled)
 387                 return;
 388
 389         __debug_object_init(addr, descr, 0);
 390 }
 391 EXPORT_SYMBOL_GPL(debug_object_init);
 392
 393 /**
 394  * debug_object_init_on_stack - debug checks when an object on stack is
 395  *                              initialized
 396  * @addr:       address of the object
 397  * @descr:      pointer to an object specific debug description structure
 398  */
 399 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 400 {
 401         if (!debug_objects_enabled)
 402                 return;
 403
 404         __debug_object_init(addr, descr, 1);
 405 }
 406 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 407
 408 /**
 409  * debug_object_activate - debug checks when an object is activated
 410  * @addr:       address of the object
 411  * @descr:      pointer to an object specific debug description structure
 412  * Returns 0 for success, -EINVAL for check failed.
 413  */
 414 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 415 {
 416         enum debug_obj_state state;
 417         struct debug_bucket *db;
 418         struct debug_obj *obj;
 419         unsigned long flags;
 420         int ret;
 421         struct debug_obj o = { .object = addr,
 422                                .state = ODEBUG_STATE_NOTAVAILABLE,
 423                                .descr = descr };
 424
 425         if (!debug_objects_enabled)
 426                 return 0;
 427
 428         db = get_bucket((unsigned long) addr);
 429
 430         raw_spin_lock_irqsave(&db->lock, flags);
 431
 432         obj = lookup_object(addr, db);
 433         if (obj) {
 434                 switch (obj->state) {
 435                 case ODEBUG_STATE_INIT:
 436                 case ODEBUG_STATE_INACTIVE:
 437                         obj->state = ODEBUG_STATE_ACTIVE;
 438                         ret = 0;
 439                         break;
 440
 441                 case ODEBUG_STATE_ACTIVE:
 442                         debug_print_object(obj, "activate");
 443                         state = obj->state;
 444                         raw_spin_unlock_irqrestore(&db->lock, flags);
 445                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 446                         return ret ? 0 : -EINVAL;
 447
 448                 case ODEBUG_STATE_DESTROYED:
 449                         debug_print_object(obj, "activate");
 450                         ret = -EINVAL;
 451                         break;
 452                 default:
 453                         ret = 0;
 454                         break;
 455                 }
 456                 raw_spin_unlock_irqrestore(&db->lock, flags);
 457                 return ret;
 458         }
 459
 460         raw_spin_unlock_irqrestore(&db->lock, flags);
 461         /*
 462          * We are here when a static object is activated. We
 463          * let the type specific code confirm whether this is
 464          * true or not. if true, we just make sure that the
 465          * static object is tracked in the object tracker. If
 466          * not, this must be a bug, so we try to fix it up.
 467          */
 468         if (descr->is_static_object && descr->is_static_object(addr)) {
 469                 /* track this static object */
 470                 debug_object_init(addr, descr);
 471                 debug_object_activate(addr, descr);
 472         } else {
 473                 debug_print_object(&o, "activate");
 474                 ret = debug_object_fixup(descr->fixup_activate, addr,
 475                                         ODEBUG_STATE_NOTAVAILABLE);
 476                 return ret ? 0 : -EINVAL;
 477         }
 478         return 0;
 479 }
 480 EXPORT_SYMBOL_GPL(debug_object_activate);
 481
 482 /**
 483  * debug_object_deactivate - debug checks when an object is deactivated
 484  * @addr:       address of the object
 485  * @descr:      pointer to an object specific debug description structure
 486  */
 487 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 488 {
 489         struct debug_bucket *db;
 490         struct debug_obj *obj;
 491         unsigned long flags;
 492
 493         if (!debug_objects_enabled)
 494                 return;
 495
 496         db = get_bucket((unsigned long) addr);
 497
 498         raw_spin_lock_irqsave(&db->lock, flags);
 499
 500         obj = lookup_object(addr, db);
 501         if (obj) {
 502                 switch (obj->state) {
 503                 case ODEBUG_STATE_INIT:
 504                 case ODEBUG_STATE_INACTIVE:
 505                 case ODEBUG_STATE_ACTIVE:
 506                         if (!obj->astate)
 507                                 obj->state = ODEBUG_STATE_INACTIVE;
 508                         else
 509                                 debug_print_object(obj, "deactivate");
 510                         break;
 511
 512                 case ODEBUG_STATE_DESTROYED:
 513                         debug_print_object(obj, "deactivate");
 514                         break;
 515                 default:
 516                         break;
 517                 }
 518         } else {
 519                 struct debug_obj o = { .object = addr,
 520                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 521                                        .descr = descr };
 522
 523                 debug_print_object(&o, "deactivate");
 524         }
 525
 526         raw_spin_unlock_irqrestore(&db->lock, flags);
 527 }
 528 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 529
 530 /**
 531  * debug_object_destroy - debug checks when an object is destroyed
 532  * @addr:       address of the object
 533  * @descr:      pointer to an object specific debug description structure
 534  */
 535 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 536 {
 537         enum debug_obj_state state;
 538         struct debug_bucket *db;
 539         struct debug_obj *obj;
 540         unsigned long flags;
 541
 542         if (!debug_objects_enabled)
 543                 return;
 544
 545         db = get_bucket((unsigned long) addr);
 546
 547         raw_spin_lock_irqsave(&db->lock, flags);
 548
 549         obj = lookup_object(addr, db);
 550         if (!obj)
 551                 goto out_unlock;
 552
 553         switch (obj->state) {
 554         case ODEBUG_STATE_NONE:
 555         case ODEBUG_STATE_INIT:
 556         case ODEBUG_STATE_INACTIVE:
 557                 obj->state = ODEBUG_STATE_DESTROYED;
 558                 break;
 559         case ODEBUG_STATE_ACTIVE:
 560                 debug_print_object(obj, "destroy");
 561                 state = obj->state;
 562                 raw_spin_unlock_irqrestore(&db->lock, flags);
 563                 debug_object_fixup(descr->fixup_destroy, addr, state);
 564                 return;
 565
 566         case ODEBUG_STATE_DESTROYED:
 567                 debug_print_object(obj, "destroy");
 568                 break;
 569         default:
 570                 break;
 571         }
 572 out_unlock:
 573         raw_spin_unlock_irqrestore(&db->lock, flags);
 574 }
 575 EXPORT_SYMBOL_GPL(debug_object_destroy);
 576
 577 /**
 578  * debug_object_free - debug checks when an object is freed
 579  * @addr:       address of the object
 580  * @descr:      pointer to an object specific debug description structure
 581  */
 582 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 583 {
 584         enum debug_obj_state state;
 585         struct debug_bucket *db;
 586         struct debug_obj *obj;
 587         unsigned long flags;
 588
 589         if (!debug_objects_enabled)
 590                 return;
 591
 592         db = get_bucket((unsigned long) addr);
 593
 594         raw_spin_lock_irqsave(&db->lock, flags);
 595
 596         obj = lookup_object(addr, db);
 597         if (!obj)
 598                 goto out_unlock;
 599
 600         switch (obj->state) {
 601         case ODEBUG_STATE_ACTIVE:
 602                 debug_print_object(obj, "free");
 603                 state = obj->state;
 604                 raw_spin_unlock_irqrestore(&db->lock, flags);
 605                 debug_object_fixup(descr->fixup_free, addr, state);
 606                 return;
 607         default:
 608                 hlist_del(&obj->node);
 609                 raw_spin_unlock_irqrestore(&db->lock, flags);
 610                 free_object(obj);
 611                 return;
 612         }
 613 out_unlock:
 614         raw_spin_unlock_irqrestore(&db->lock, flags);
 615 }
 616 EXPORT_SYMBOL_GPL(debug_object_free);
 617
 618 /**
 619  * debug_object_assert_init - debug checks when object should be init-ed
 620  * @addr:       address of the object
 621  * @descr:      pointer to an object specific debug description structure
 622  */
 623 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 624 {
 625         struct debug_bucket *db;
 626         struct debug_obj *obj;
 627         unsigned long flags;
 628
 629         if (!debug_objects_enabled)
 630                 return;
 631
 632         db = get_bucket((unsigned long) addr);
 633
 634         raw_spin_lock_irqsave(&db->lock, flags);
 635
 636         obj = lookup_object(addr, db);
 637         if (!obj) {
 638                 struct debug_obj o = { .object = addr,
 639                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 640                                        .descr = descr };
 641
 642                 raw_spin_unlock_irqrestore(&db->lock, flags);
 643                 /*
 644                  * Maybe the object is static, and we let the type specific
 645                  * code confirm. Track this static object if true, else invoke
 646                  * fixup.
 647                  */
 648                 if (descr->is_static_object && descr->is_static_object(addr)) {
 649                         /* Track this static object */
 650                         debug_object_init(addr, descr);
 651                 } else {
 652                         debug_print_object(&o, "assert_init");
 653                         debug_object_fixup(descr->fixup_assert_init, addr,
 654                                            ODEBUG_STATE_NOTAVAILABLE);
 655                 }
 656                 return;
 657         }
 658
 659         raw_spin_unlock_irqrestore(&db->lock, flags);
 660 }
 661 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 662
 663 /**
 664  * debug_object_active_state - debug checks object usage state machine
 665  * @addr:       address of the object
 666  * @descr:      pointer to an object specific debug description structure
 667  * @expect:     expected state
 668  * @next:       state to move to if expected state is found
 669  */
 670 void
 671 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 672                           unsigned int expect, unsigned int next)
 673 {
 674         struct debug_bucket *db;
 675         struct debug_obj *obj;
 676         unsigned long flags;
 677
 678         if (!debug_objects_enabled)
 679                 return;
 680
 681         db = get_bucket((unsigned long) addr);
 682
 683         raw_spin_lock_irqsave(&db->lock, flags);
 684
 685         obj = lookup_object(addr, db);
 686         if (obj) {
 687                 switch (obj->state) {
 688                 case ODEBUG_STATE_ACTIVE:
 689                         if (obj->astate == expect)
 690                                 obj->astate = next;
 691                         else
 692                                 debug_print_object(obj, "active_state");
 693                         break;
 694
 695                 default:
 696                         debug_print_object(obj, "active_state");
 697                         break;
 698                 }
 699         } else {
 700                 struct debug_obj o = { .object = addr,
 701                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 702                                        .descr = descr };
 703
 704                 debug_print_object(&o, "active_state");
 705         }
 706
 707         raw_spin_unlock_irqrestore(&db->lock, flags);
 708 }
 709 EXPORT_SYMBOL_GPL(debug_object_active_state);
 710
 711 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 712 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 713 {
 714         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 715         struct hlist_node *tmp;
 716         HLIST_HEAD(freelist);
 717         struct debug_obj_descr *descr;
 718         enum debug_obj_state state;
 719         struct debug_bucket *db;
 720         struct debug_obj *obj;
 721         int cnt;
 722
 723         saddr = (unsigned long) address;
 724         eaddr = saddr + size;
 725         paddr = saddr & ODEBUG_CHUNK_MASK;
 726         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 727         chunks >>= ODEBUG_CHUNK_SHIFT;
 728
 729         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 730                 db = get_bucket(paddr);
 731
 732 repeat:
 733                 cnt = 0;
 734                 raw_spin_lock_irqsave(&db->lock, flags);
 735                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 736                         cnt++;
 737                         oaddr = (unsigned long) obj->object;
 738                         if (oaddr < saddr || oaddr >= eaddr)
 739                                 continue;
 740
 741                         switch (obj->state) {
 742                         case ODEBUG_STATE_ACTIVE:
 743                                 debug_print_object(obj, "free");
 744                                 descr = obj->descr;
 745                                 state = obj->state;
 746                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 747                                 debug_object_fixup(descr->fixup_free,
 748                                                    (void *) oaddr, state);
 749                                 goto repeat;
 750                         default:
 751                                 hlist_del(&obj->node);
 752                                 hlist_add_head(&obj->node, &freelist);
 753                                 break;
 754                         }
 755                 }
 756                 raw_spin_unlock_irqrestore(&db->lock, flags);
 757
 758                 /* Now free them */
 759                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 760                         hlist_del(&obj->node);
 761                         free_object(obj);
 762                 }
 763
 764                 if (cnt > debug_objects_maxchain)
 765                         debug_objects_maxchain = cnt;
 766         }
 767 }
 768
 769 void debug_check_no_obj_freed(const void *address, unsigned long size)
 770 {
 771         if (debug_objects_enabled)
 772                 __debug_check_no_obj_freed(address, size);
 773 }
 774 #endif
 775
 776 #ifdef CONFIG_DEBUG_FS
 777
 778 static int debug_stats_show(struct seq_file *m, void *v)
 779 {
 780         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 781         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 782         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 783         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 784         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 785         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 786         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 787         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 788         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 789         return 0;
 790 }
 791
 792 static int debug_stats_open(struct inode *inode, struct file *filp)
 793 {
 794         return single_open(filp, debug_stats_show, NULL);
 795 }
 796
 797 static const struct file_operations debug_stats_fops = {
 798         .open           = debug_stats_open,
 799         .read           = seq_read,
 800         .llseek         = seq_lseek,
 801         .release        = single_release,
 802 };
 803
 804 static int __init debug_objects_init_debugfs(void)
 805 {
 806         struct dentry *dbgdir, *dbgstats;
 807
 808         if (!debug_objects_enabled)
 809                 return 0;
 810
 811         dbgdir = debugfs_create_dir("debug_objects", NULL);
 812         if (!dbgdir)
 813                 return -ENOMEM;
 814
 815         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 816                                        &debug_stats_fops);
 817         if (!dbgstats)
 818                 goto err;
 819
 820         return 0;
 821
 822 err:
 823         debugfs_remove(dbgdir);
 824
 825         return -ENOMEM;
 826 }
 827 __initcall(debug_objects_init_debugfs);
 828
 829 #else
 830 static inline void debug_objects_init_debugfs(void) { }
 831 #endif
 832
 833 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 834
 835 /* Random data structure for the self test */
 836 struct self_test {
 837         unsigned long   dummy1[6];
 838         int             static_init;
 839         unsigned long   dummy2[3];
 840 };
 841
 842 static __initdata struct debug_obj_descr descr_type_test;
 843
 844 static bool __init is_static_object(void *addr)
 845 {
 846         struct self_test *obj = addr;
 847
 848         return obj->static_init;
 849 }
 850
 851 /*
 852  * fixup_init is called when:
 853  * - an active object is initialized
 854  */
 855 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 856 {
 857         struct self_test *obj = addr;
 858
 859         switch (state) {
 860         case ODEBUG_STATE_ACTIVE:
 861                 debug_object_deactivate(obj, &descr_type_test);
 862                 debug_object_init(obj, &descr_type_test);
 863                 return true;
 864         default:
 865                 return false;
 866         }
 867 }
 868
 869 /*
 870  * fixup_activate is called when:
 871  * - an active object is activated
 872  * - an unknown non-static object is activated
 873  */
 874 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 875 {
 876         struct self_test *obj = addr;
 877
 878         switch (state) {
 879         case ODEBUG_STATE_NOTAVAILABLE:
 880                 return true;
 881         case ODEBUG_STATE_ACTIVE:
 882                 debug_object_deactivate(obj, &descr_type_test);
 883                 debug_object_activate(obj, &descr_type_test);
 884                 return true;
 885
 886         default:
 887                 return false;
 888         }
 889 }
 890
 891 /*
 892  * fixup_destroy is called when:
 893  * - an active object is destroyed
 894  */
 895 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 896 {
 897         struct self_test *obj = addr;
 898
 899         switch (state) {
 900         case ODEBUG_STATE_ACTIVE:
 901                 debug_object_deactivate(obj, &descr_type_test);
 902                 debug_object_destroy(obj, &descr_type_test);
 903                 return true;
 904         default:
 905                 return false;
 906         }
 907 }
 908
 909 /*
 910  * fixup_free is called when:
 911  * - an active object is freed
 912  */
 913 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 914 {
 915         struct self_test *obj = addr;
 916
 917         switch (state) {
 918         case ODEBUG_STATE_ACTIVE:
 919                 debug_object_deactivate(obj, &descr_type_test);
 920                 debug_object_free(obj, &descr_type_test);
 921                 return true;
 922         default:
 923                 return false;
 924         }
 925 }
 926
 927 static int __init
 928 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 929 {
 930         struct debug_bucket *db;
 931         struct debug_obj *obj;
 932         unsigned long flags;
 933         int res = -EINVAL;
 934
 935         db = get_bucket((unsigned long) addr);
 936
 937         raw_spin_lock_irqsave(&db->lock, flags);
 938
 939         obj = lookup_object(addr, db);
 940         if (!obj && state != ODEBUG_STATE_NONE) {
 941                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 942                 goto out;
 943         }
 944         if (obj && obj->state != state) {
 945                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 946                        obj->state, state);
 947                 goto out;
 948         }
 949         if (fixups != debug_objects_fixups) {
 950                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 951                        fixups, debug_objects_fixups);
 952                 goto out;
 953         }
 954         if (warnings != debug_objects_warnings) {
 955                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 956                        warnings, debug_objects_warnings);
 957                 goto out;
 958         }
 959         res = 0;
 960 out:
 961         raw_spin_unlock_irqrestore(&db->lock, flags);
 962         if (res)
 963                 debug_objects_enabled = 0;
 964         return res;
 965 }
 966
 967 static __initdata struct debug_obj_descr descr_type_test = {
 968         .name                   = "selftest",
 969         .is_static_object       = is_static_object,
 970         .fixup_init             = fixup_init,
 971         .fixup_activate         = fixup_activate,
 972         .fixup_destroy          = fixup_destroy,
 973         .fixup_free             = fixup_free,
 974 };
 975
 976 static __initdata struct self_test obj = { .static_init = 0 };
 977
 978 static void __init debug_objects_selftest(void)
 979 {
 980         int fixups, oldfixups, warnings, oldwarnings;
 981         unsigned long flags;
 982
 983         local_irq_save(flags);
 984
 985         fixups = oldfixups = debug_objects_fixups;
 986         warnings = oldwarnings = debug_objects_warnings;
 987         descr_test = &descr_type_test;
 988
 989         debug_object_init(&obj, &descr_type_test);
 990         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 991                 goto out;
 992         debug_object_activate(&obj, &descr_type_test);
 993         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 994                 goto out;
 995         debug_object_activate(&obj, &descr_type_test);
 996         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 997                 goto out;
 998         debug_object_deactivate(&obj, &descr_type_test);
 999         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1000                 goto out;
1001         debug_object_destroy(&obj, &descr_type_test);
1002         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1003                 goto out;
1004         debug_object_init(&obj, &descr_type_test);
1005         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1006                 goto out;
1007         debug_object_activate(&obj, &descr_type_test);
1008         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1009                 goto out;
1010         debug_object_deactivate(&obj, &descr_type_test);
1011         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1012                 goto out;
1013         debug_object_free(&obj, &descr_type_test);
1014         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1015                 goto out;
1016
1017         obj.static_init = 1;
1018         debug_object_activate(&obj, &descr_type_test);
1019         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1020                 goto out;
1021         debug_object_init(&obj, &descr_type_test);
1022         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1023                 goto out;
1024         debug_object_free(&obj, &descr_type_test);
1025         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1026                 goto out;
1027
1028 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1029         debug_object_init(&obj, &descr_type_test);
1030         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1031                 goto out;
1032         debug_object_activate(&obj, &descr_type_test);
1033         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1034                 goto out;
1035         __debug_check_no_obj_freed(&obj, sizeof(obj));
1036         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1037                 goto out;
1038 #endif
1039         pr_info("selftest passed\n");
1040
1041 out:
1042         debug_objects_fixups = oldfixups;
1043         debug_objects_warnings = oldwarnings;
1044         descr_test = NULL;
1045
1046         local_irq_restore(flags);
1047 }
1048 #else
1049 static inline void debug_objects_selftest(void) { }
1050 #endif
1051
1052 /*
1053  * Called during early boot to initialize the hash buckets and link
1054  * the static object pool objects into the poll list. After this call
1055  * the object tracker is fully operational.
1056  */
1057 void __init debug_objects_early_init(void)
1058 {
1059         int i;
1060
1061         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1062                 raw_spin_lock_init(&obj_hash[i].lock);
1063
1064         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1065                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1066 }
1067
1068 /*
1069  * Convert the statically allocated objects to dynamic ones:
1070  */
1071 static int __init debug_objects_replace_static_objects(void)
1072 {
1073         struct debug_bucket *db = obj_hash;
1074         struct hlist_node *tmp;
1075         struct debug_obj *obj, *new;
1076         HLIST_HEAD(objects);
1077         int i, cnt = 0;
1078
1079         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1080                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1081                 if (!obj)
1082                         goto free;
1083                 hlist_add_head(&obj->node, &objects);
1084         }
1085
1086         /*
1087          * When debug_objects_mem_init() is called we know that only
1088          * one CPU is up, so disabling interrupts is enough
1089          * protection. This avoids the lockdep hell of lock ordering.
1090          */
1091         local_irq_disable();
1092
1093         /* Remove the statically allocated objects from the pool */
1094         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1095                 hlist_del(&obj->node);
1096         /* Move the allocated objects to the pool */
1097         hlist_move_list(&objects, &obj_pool);
1098
1099         /* Replace the active object references */
1100         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1101                 hlist_move_list(&db->list, &objects);
1102
1103                 hlist_for_each_entry(obj, &objects, node) {
1104                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1105                         hlist_del(&new->node);
1106                         /* copy object data */
1107                         *new = *obj;
1108                         hlist_add_head(&new->node, &db->list);
1109                         cnt++;
1110                 }
1111         }
1112         local_irq_enable();
1113
1114         pr_debug("%d of %d active objects replaced\n",
1115                  cnt, obj_pool_used);
1116         return 0;
1117 free:
1118         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1119                 hlist_del(&obj->node);
1120                 kmem_cache_free(obj_cache, obj);
1121         }
1122         return -ENOMEM;
1123 }
1124
1125 /*
1126  * Called after the kmem_caches are functional to setup a dedicated
1127  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1128  * prevents that the debug code is called on kmem_cache_free() for the
1129  * debug tracker objects to avoid recursive calls.
1130  */
1131 void __init debug_objects_mem_init(void)
1132 {
1133         if (!debug_objects_enabled)
1134                 return;
1135
1136         obj_cache = kmem_cache_create("debug_objects_cache",
1137                                       sizeof (struct debug_obj), 0,
1138                                       SLAB_DEBUG_OBJECTS, NULL);
1139
1140         if (!obj_cache || debug_objects_replace_static_objects()) {
1141                 debug_objects_enabled = 0;
1142                 if (obj_cache)
1143                         kmem_cache_destroy(obj_cache);
1144                 pr_warn("out of memory.\n");
1145         } else
1146                 debug_objects_selftest();
1147
1148         /*
1149          * Increase the thresholds for allocating and freeing objects
1150          * according to the number of possible CPUs available in the system.
1151          */
1152         debug_objects_pool_size += num_possible_cpus() * 32;
1153         debug_objects_pool_min_level += num_possible_cpus() * 4;
1154 }