lib/debugobjects.c

   1 /*
   2  * Generic infrastructure for lifetime debugging of objects.
   3  *
   4  * Started by Thomas Gleixner
   5  *
   6  * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
   7  *
   8  * For licencing details see kernel-base/COPYING
   9  */
  10
  11 #define pr_fmt(fmt) "ODEBUG: " fmt
  12
  13 #include <linux/debugobjects.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/sched.h>
  16 #include <linux/sched/task_stack.h>
  17 #include <linux/seq_file.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/slab.h>
  20 #include <linux/hash.h>
  21 #include <linux/kmemleak.h>
  22
  23 #define ODEBUG_HASH_BITS        14
  24 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  25
  26 #define ODEBUG_POOL_SIZE        1024
  27 #define ODEBUG_POOL_MIN_LEVEL   256
  28
  29 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  30 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  31 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  32
  33 struct debug_bucket {
  34         struct hlist_head       list;
  35         raw_spinlock_t          lock;
  36 };
  37
  38 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  39
  40 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  41
  42 static DEFINE_RAW_SPINLOCK(pool_lock);
  43
  44 static HLIST_HEAD(obj_pool);
  45 static HLIST_HEAD(obj_to_free);
  46
  47 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  48 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  49 static int                      obj_pool_used;
  50 static int                      obj_pool_max_used;
  51 /* The number of objs on the global free list */
  52 static int                      obj_nr_tofree;
  53 static struct kmem_cache        *obj_cache;
  54
  55 static int                      debug_objects_maxchain __read_mostly;
  56 static int __maybe_unused       debug_objects_maxchecked __read_mostly;
  57 static int                      debug_objects_fixups __read_mostly;
  58 static int                      debug_objects_warnings __read_mostly;
  59 static int                      debug_objects_enabled __read_mostly
  60                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  61 static int                      debug_objects_pool_size __read_mostly
  62                                 = ODEBUG_POOL_SIZE;
  63 static int                      debug_objects_pool_min_level __read_mostly
  64                                 = ODEBUG_POOL_MIN_LEVEL;
  65 static struct debug_obj_descr   *descr_test  __read_mostly;
  66
  67 /*
  68  * Track numbers of kmem_cache_alloc()/free() calls done.
  69  */
  70 static int                      debug_objects_allocated;
  71 static int                      debug_objects_freed;
  72
  73 static void free_obj_work(struct work_struct *work);
  74 static DECLARE_WORK(debug_obj_work, free_obj_work);
  75
  76 static int __init enable_object_debug(char *str)
  77 {
  78         debug_objects_enabled = 1;
  79         return 0;
  80 }
  81
  82 static int __init disable_object_debug(char *str)
  83 {
  84         debug_objects_enabled = 0;
  85         return 0;
  86 }
  87
  88 early_param("debug_objects", enable_object_debug);
  89 early_param("no_debug_objects", disable_object_debug);
  90
  91 static const char *obj_states[ODEBUG_STATE_MAX] = {
  92         [ODEBUG_STATE_NONE]             = "none",
  93         [ODEBUG_STATE_INIT]             = "initialized",
  94         [ODEBUG_STATE_INACTIVE]         = "inactive",
  95         [ODEBUG_STATE_ACTIVE]           = "active",
  96         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  97         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  98 };
  99
 100 static void fill_pool(void)
 101 {
 102         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
 103         struct debug_obj *new, *obj;
 104         unsigned long flags;
 105
 106         if (likely(obj_pool_free >= debug_objects_pool_min_level))
 107                 return;
 108
 109         /*
 110          * Reuse objs from the global free list; they will be reinitialized
 111          * when allocating.
 112          */
 113         while (obj_nr_tofree && (obj_pool_free < obj_pool_min_free)) {
 114                 raw_spin_lock_irqsave(&pool_lock, flags);
 115                 /*
 116                  * Recheck with the lock held as the worker thread might have
 117                  * won the race and freed the global free list already.
 118                  */
 119                 if (obj_nr_tofree) {
 120                         obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 121                         hlist_del(&obj->node);
 122                         obj_nr_tofree--;
 123                         hlist_add_head(&obj->node, &obj_pool);
 124                         obj_pool_free++;
 125                 }
 126                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 127         }
 128
 129         if (unlikely(!obj_cache))
 130                 return;
 131
 132         while (obj_pool_free < debug_objects_pool_min_level) {
 133
 134                 new = kmem_cache_zalloc(obj_cache, gfp);
 135                 if (!new)
 136                         return;
 137
 138                 kmemleak_ignore(new);
 139                 raw_spin_lock_irqsave(&pool_lock, flags);
 140                 hlist_add_head(&new->node, &obj_pool);
 141                 debug_objects_allocated++;
 142                 obj_pool_free++;
 143                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 144         }
 145 }
 146
 147 /*
 148  * Lookup an object in the hash bucket.
 149  */
 150 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 151 {
 152         struct debug_obj *obj;
 153         int cnt = 0;
 154
 155         hlist_for_each_entry(obj, &b->list, node) {
 156                 cnt++;
 157                 if (obj->object == addr)
 158                         return obj;
 159         }
 160         if (cnt > debug_objects_maxchain)
 161                 debug_objects_maxchain = cnt;
 162
 163         return NULL;
 164 }
 165
 166 /*
 167  * Allocate a new object. If the pool is empty, switch off the debugger.
 168  * Must be called with interrupts disabled.
 169  */
 170 static struct debug_obj *
 171 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 172 {
 173         struct debug_obj *obj = NULL;
 174
 175         raw_spin_lock(&pool_lock);
 176         if (obj_pool.first) {
 177                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 178
 179                 obj->object = addr;
 180                 obj->descr  = descr;
 181                 obj->state  = ODEBUG_STATE_NONE;
 182                 obj->astate = 0;
 183                 hlist_del(&obj->node);
 184
 185                 hlist_add_head(&obj->node, &b->list);
 186
 187                 obj_pool_used++;
 188                 if (obj_pool_used > obj_pool_max_used)
 189                         obj_pool_max_used = obj_pool_used;
 190
 191                 obj_pool_free--;
 192                 if (obj_pool_free < obj_pool_min_free)
 193                         obj_pool_min_free = obj_pool_free;
 194         }
 195         raw_spin_unlock(&pool_lock);
 196
 197         return obj;
 198 }
 199
 200 /*
 201  * workqueue function to free objects.
 202  *
 203  * To reduce contention on the global pool_lock, the actual freeing of
 204  * debug objects will be delayed if the pool_lock is busy.
 205  */
 206 static void free_obj_work(struct work_struct *work)
 207 {
 208         struct hlist_node *tmp;
 209         struct debug_obj *obj;
 210         unsigned long flags;
 211         HLIST_HEAD(tofree);
 212
 213         if (!raw_spin_trylock_irqsave(&pool_lock, flags))
 214                 return;
 215
 216         /*
 217          * The objs on the pool list might be allocated before the work is
 218          * run, so recheck if pool list it full or not, if not fill pool
 219          * list from the global free list
 220          */
 221         while (obj_nr_tofree && obj_pool_free < debug_objects_pool_size) {
 222                 obj = hlist_entry(obj_to_free.first, typeof(*obj), node);
 223                 hlist_del(&obj->node);
 224                 hlist_add_head(&obj->node, &obj_pool);
 225                 obj_pool_free++;
 226                 obj_nr_tofree--;
 227         }
 228
 229         /*
 230          * Pool list is already full and there are still objs on the free
 231          * list. Move remaining free objs to a temporary list to free the
 232          * memory outside the pool_lock held region.
 233          */
 234         if (obj_nr_tofree) {
 235                 hlist_move_list(&obj_to_free, &tofree);
 236                 debug_objects_freed += obj_nr_tofree;
 237                 obj_nr_tofree = 0;
 238         }
 239         raw_spin_unlock_irqrestore(&pool_lock, flags);
 240
 241         hlist_for_each_entry_safe(obj, tmp, &tofree, node) {
 242                 hlist_del(&obj->node);
 243                 kmem_cache_free(obj_cache, obj);
 244         }
 245 }
 246
 247 static bool __free_object(struct debug_obj *obj)
 248 {
 249         unsigned long flags;
 250         bool work;
 251
 252         raw_spin_lock_irqsave(&pool_lock, flags);
 253         work = (obj_pool_free > debug_objects_pool_size) && obj_cache;
 254         obj_pool_used--;
 255
 256         if (work) {
 257                 obj_nr_tofree++;
 258                 hlist_add_head(&obj->node, &obj_to_free);
 259         } else {
 260                 obj_pool_free++;
 261                 hlist_add_head(&obj->node, &obj_pool);
 262         }
 263         raw_spin_unlock_irqrestore(&pool_lock, flags);
 264         return work;
 265 }
 266
 267 /*
 268  * Put the object back into the pool and schedule work to free objects
 269  * if necessary.
 270  */
 271 static void free_object(struct debug_obj *obj)
 272 {
 273         if (__free_object(obj))
 274                 schedule_work(&debug_obj_work);
 275 }
 276
 277 /*
 278  * We run out of memory. That means we probably have tons of objects
 279  * allocated.
 280  */
 281 static void debug_objects_oom(void)
 282 {
 283         struct debug_bucket *db = obj_hash;
 284         struct hlist_node *tmp;
 285         HLIST_HEAD(freelist);
 286         struct debug_obj *obj;
 287         unsigned long flags;
 288         int i;
 289
 290         pr_warn("Out of memory. ODEBUG disabled\n");
 291
 292         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 293                 raw_spin_lock_irqsave(&db->lock, flags);
 294                 hlist_move_list(&db->list, &freelist);
 295                 raw_spin_unlock_irqrestore(&db->lock, flags);
 296
 297                 /* Now free them */
 298                 hlist_for_each_entry_safe(obj, tmp, &freelist, node) {
 299                         hlist_del(&obj->node);
 300                         free_object(obj);
 301                 }
 302         }
 303 }
 304
 305 /*
 306  * We use the pfn of the address for the hash. That way we can check
 307  * for freed objects simply by checking the affected bucket.
 308  */
 309 static struct debug_bucket *get_bucket(unsigned long addr)
 310 {
 311         unsigned long hash;
 312
 313         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 314         return &obj_hash[hash];
 315 }
 316
 317 static void debug_print_object(struct debug_obj *obj, char *msg)
 318 {
 319         struct debug_obj_descr *descr = obj->descr;
 320         static int limit;
 321
 322         if (limit < 5 && descr != descr_test) {
 323                 void *hint = descr->debug_hint ?
 324                         descr->debug_hint(obj->object) : NULL;
 325                 limit++;
 326                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 327                                  "object type: %s hint: %pS\n",
 328                         msg, obj_states[obj->state], obj->astate,
 329                         descr->name, hint);
 330         }
 331         debug_objects_warnings++;
 332 }
 333
 334 /*
 335  * Try to repair the damage, so we have a better chance to get useful
 336  * debug output.
 337  */
 338 static bool
 339 debug_object_fixup(bool (*fixup)(void *addr, enum debug_obj_state state),
 340                    void * addr, enum debug_obj_state state)
 341 {
 342         if (fixup && fixup(addr, state)) {
 343                 debug_objects_fixups++;
 344                 return true;
 345         }
 346         return false;
 347 }
 348
 349 static void debug_object_is_on_stack(void *addr, int onstack)
 350 {
 351         int is_on_stack;
 352         static int limit;
 353
 354         if (limit > 4)
 355                 return;
 356
 357         is_on_stack = object_is_on_stack(addr);
 358         if (is_on_stack == onstack)
 359                 return;
 360
 361         limit++;
 362         if (is_on_stack)
 363                 pr_warn("object is on stack, but not annotated\n");
 364         else
 365                 pr_warn("object is not on stack, but annotated\n");
 366         WARN_ON(1);
 367 }
 368
 369 static void
 370 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 371 {
 372         enum debug_obj_state state;
 373         struct debug_bucket *db;
 374         struct debug_obj *obj;
 375         unsigned long flags;
 376
 377         fill_pool();
 378
 379         db = get_bucket((unsigned long) addr);
 380
 381         raw_spin_lock_irqsave(&db->lock, flags);
 382
 383         obj = lookup_object(addr, db);
 384         if (!obj) {
 385                 obj = alloc_object(addr, db, descr);
 386                 if (!obj) {
 387                         debug_objects_enabled = 0;
 388                         raw_spin_unlock_irqrestore(&db->lock, flags);
 389                         debug_objects_oom();
 390                         return;
 391                 }
 392                 debug_object_is_on_stack(addr, onstack);
 393         }
 394
 395         switch (obj->state) {
 396         case ODEBUG_STATE_NONE:
 397         case ODEBUG_STATE_INIT:
 398         case ODEBUG_STATE_INACTIVE:
 399                 obj->state = ODEBUG_STATE_INIT;
 400                 break;
 401
 402         case ODEBUG_STATE_ACTIVE:
 403                 debug_print_object(obj, "init");
 404                 state = obj->state;
 405                 raw_spin_unlock_irqrestore(&db->lock, flags);
 406                 debug_object_fixup(descr->fixup_init, addr, state);
 407                 return;
 408
 409         case ODEBUG_STATE_DESTROYED:
 410                 debug_print_object(obj, "init");
 411                 break;
 412         default:
 413                 break;
 414         }
 415
 416         raw_spin_unlock_irqrestore(&db->lock, flags);
 417 }
 418
 419 /**
 420  * debug_object_init - debug checks when an object is initialized
 421  * @addr:       address of the object
 422  * @descr:      pointer to an object specific debug description structure
 423  */
 424 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 425 {
 426         if (!debug_objects_enabled)
 427                 return;
 428
 429         __debug_object_init(addr, descr, 0);
 430 }
 431 EXPORT_SYMBOL_GPL(debug_object_init);
 432
 433 /**
 434  * debug_object_init_on_stack - debug checks when an object on stack is
 435  *                              initialized
 436  * @addr:       address of the object
 437  * @descr:      pointer to an object specific debug description structure
 438  */
 439 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 440 {
 441         if (!debug_objects_enabled)
 442                 return;
 443
 444         __debug_object_init(addr, descr, 1);
 445 }
 446 EXPORT_SYMBOL_GPL(debug_object_init_on_stack);
 447
 448 /**
 449  * debug_object_activate - debug checks when an object is activated
 450  * @addr:       address of the object
 451  * @descr:      pointer to an object specific debug description structure
 452  * Returns 0 for success, -EINVAL for check failed.
 453  */
 454 int debug_object_activate(void *addr, struct debug_obj_descr *descr)
 455 {
 456         enum debug_obj_state state;
 457         struct debug_bucket *db;
 458         struct debug_obj *obj;
 459         unsigned long flags;
 460         int ret;
 461         struct debug_obj o = { .object = addr,
 462                                .state = ODEBUG_STATE_NOTAVAILABLE,
 463                                .descr = descr };
 464
 465         if (!debug_objects_enabled)
 466                 return 0;
 467
 468         db = get_bucket((unsigned long) addr);
 469
 470         raw_spin_lock_irqsave(&db->lock, flags);
 471
 472         obj = lookup_object(addr, db);
 473         if (obj) {
 474                 switch (obj->state) {
 475                 case ODEBUG_STATE_INIT:
 476                 case ODEBUG_STATE_INACTIVE:
 477                         obj->state = ODEBUG_STATE_ACTIVE;
 478                         ret = 0;
 479                         break;
 480
 481                 case ODEBUG_STATE_ACTIVE:
 482                         debug_print_object(obj, "activate");
 483                         state = obj->state;
 484                         raw_spin_unlock_irqrestore(&db->lock, flags);
 485                         ret = debug_object_fixup(descr->fixup_activate, addr, state);
 486                         return ret ? 0 : -EINVAL;
 487
 488                 case ODEBUG_STATE_DESTROYED:
 489                         debug_print_object(obj, "activate");
 490                         ret = -EINVAL;
 491                         break;
 492                 default:
 493                         ret = 0;
 494                         break;
 495                 }
 496                 raw_spin_unlock_irqrestore(&db->lock, flags);
 497                 return ret;
 498         }
 499
 500         raw_spin_unlock_irqrestore(&db->lock, flags);
 501         /*
 502          * We are here when a static object is activated. We
 503          * let the type specific code confirm whether this is
 504          * true or not. if true, we just make sure that the
 505          * static object is tracked in the object tracker. If
 506          * not, this must be a bug, so we try to fix it up.
 507          */
 508         if (descr->is_static_object && descr->is_static_object(addr)) {
 509                 /* track this static object */
 510                 debug_object_init(addr, descr);
 511                 debug_object_activate(addr, descr);
 512         } else {
 513                 debug_print_object(&o, "activate");
 514                 ret = debug_object_fixup(descr->fixup_activate, addr,
 515                                         ODEBUG_STATE_NOTAVAILABLE);
 516                 return ret ? 0 : -EINVAL;
 517         }
 518         return 0;
 519 }
 520 EXPORT_SYMBOL_GPL(debug_object_activate);
 521
 522 /**
 523  * debug_object_deactivate - debug checks when an object is deactivated
 524  * @addr:       address of the object
 525  * @descr:      pointer to an object specific debug description structure
 526  */
 527 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 528 {
 529         struct debug_bucket *db;
 530         struct debug_obj *obj;
 531         unsigned long flags;
 532
 533         if (!debug_objects_enabled)
 534                 return;
 535
 536         db = get_bucket((unsigned long) addr);
 537
 538         raw_spin_lock_irqsave(&db->lock, flags);
 539
 540         obj = lookup_object(addr, db);
 541         if (obj) {
 542                 switch (obj->state) {
 543                 case ODEBUG_STATE_INIT:
 544                 case ODEBUG_STATE_INACTIVE:
 545                 case ODEBUG_STATE_ACTIVE:
 546                         if (!obj->astate)
 547                                 obj->state = ODEBUG_STATE_INACTIVE;
 548                         else
 549                                 debug_print_object(obj, "deactivate");
 550                         break;
 551
 552                 case ODEBUG_STATE_DESTROYED:
 553                         debug_print_object(obj, "deactivate");
 554                         break;
 555                 default:
 556                         break;
 557                 }
 558         } else {
 559                 struct debug_obj o = { .object = addr,
 560                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 561                                        .descr = descr };
 562
 563                 debug_print_object(&o, "deactivate");
 564         }
 565
 566         raw_spin_unlock_irqrestore(&db->lock, flags);
 567 }
 568 EXPORT_SYMBOL_GPL(debug_object_deactivate);
 569
 570 /**
 571  * debug_object_destroy - debug checks when an object is destroyed
 572  * @addr:       address of the object
 573  * @descr:      pointer to an object specific debug description structure
 574  */
 575 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 576 {
 577         enum debug_obj_state state;
 578         struct debug_bucket *db;
 579         struct debug_obj *obj;
 580         unsigned long flags;
 581
 582         if (!debug_objects_enabled)
 583                 return;
 584
 585         db = get_bucket((unsigned long) addr);
 586
 587         raw_spin_lock_irqsave(&db->lock, flags);
 588
 589         obj = lookup_object(addr, db);
 590         if (!obj)
 591                 goto out_unlock;
 592
 593         switch (obj->state) {
 594         case ODEBUG_STATE_NONE:
 595         case ODEBUG_STATE_INIT:
 596         case ODEBUG_STATE_INACTIVE:
 597                 obj->state = ODEBUG_STATE_DESTROYED;
 598                 break;
 599         case ODEBUG_STATE_ACTIVE:
 600                 debug_print_object(obj, "destroy");
 601                 state = obj->state;
 602                 raw_spin_unlock_irqrestore(&db->lock, flags);
 603                 debug_object_fixup(descr->fixup_destroy, addr, state);
 604                 return;
 605
 606         case ODEBUG_STATE_DESTROYED:
 607                 debug_print_object(obj, "destroy");
 608                 break;
 609         default:
 610                 break;
 611         }
 612 out_unlock:
 613         raw_spin_unlock_irqrestore(&db->lock, flags);
 614 }
 615 EXPORT_SYMBOL_GPL(debug_object_destroy);
 616
 617 /**
 618  * debug_object_free - debug checks when an object is freed
 619  * @addr:       address of the object
 620  * @descr:      pointer to an object specific debug description structure
 621  */
 622 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 623 {
 624         enum debug_obj_state state;
 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                 goto out_unlock;
 639
 640         switch (obj->state) {
 641         case ODEBUG_STATE_ACTIVE:
 642                 debug_print_object(obj, "free");
 643                 state = obj->state;
 644                 raw_spin_unlock_irqrestore(&db->lock, flags);
 645                 debug_object_fixup(descr->fixup_free, addr, state);
 646                 return;
 647         default:
 648                 hlist_del(&obj->node);
 649                 raw_spin_unlock_irqrestore(&db->lock, flags);
 650                 free_object(obj);
 651                 return;
 652         }
 653 out_unlock:
 654         raw_spin_unlock_irqrestore(&db->lock, flags);
 655 }
 656 EXPORT_SYMBOL_GPL(debug_object_free);
 657
 658 /**
 659  * debug_object_assert_init - debug checks when object should be init-ed
 660  * @addr:       address of the object
 661  * @descr:      pointer to an object specific debug description structure
 662  */
 663 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 664 {
 665         struct debug_bucket *db;
 666         struct debug_obj *obj;
 667         unsigned long flags;
 668
 669         if (!debug_objects_enabled)
 670                 return;
 671
 672         db = get_bucket((unsigned long) addr);
 673
 674         raw_spin_lock_irqsave(&db->lock, flags);
 675
 676         obj = lookup_object(addr, db);
 677         if (!obj) {
 678                 struct debug_obj o = { .object = addr,
 679                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 680                                        .descr = descr };
 681
 682                 raw_spin_unlock_irqrestore(&db->lock, flags);
 683                 /*
 684                  * Maybe the object is static, and we let the type specific
 685                  * code confirm. Track this static object if true, else invoke
 686                  * fixup.
 687                  */
 688                 if (descr->is_static_object && descr->is_static_object(addr)) {
 689                         /* Track this static object */
 690                         debug_object_init(addr, descr);
 691                 } else {
 692                         debug_print_object(&o, "assert_init");
 693                         debug_object_fixup(descr->fixup_assert_init, addr,
 694                                            ODEBUG_STATE_NOTAVAILABLE);
 695                 }
 696                 return;
 697         }
 698
 699         raw_spin_unlock_irqrestore(&db->lock, flags);
 700 }
 701 EXPORT_SYMBOL_GPL(debug_object_assert_init);
 702
 703 /**
 704  * debug_object_active_state - debug checks object usage state machine
 705  * @addr:       address of the object
 706  * @descr:      pointer to an object specific debug description structure
 707  * @expect:     expected state
 708  * @next:       state to move to if expected state is found
 709  */
 710 void
 711 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 712                           unsigned int expect, unsigned int next)
 713 {
 714         struct debug_bucket *db;
 715         struct debug_obj *obj;
 716         unsigned long flags;
 717
 718         if (!debug_objects_enabled)
 719                 return;
 720
 721         db = get_bucket((unsigned long) addr);
 722
 723         raw_spin_lock_irqsave(&db->lock, flags);
 724
 725         obj = lookup_object(addr, db);
 726         if (obj) {
 727                 switch (obj->state) {
 728                 case ODEBUG_STATE_ACTIVE:
 729                         if (obj->astate == expect)
 730                                 obj->astate = next;
 731                         else
 732                                 debug_print_object(obj, "active_state");
 733                         break;
 734
 735                 default:
 736                         debug_print_object(obj, "active_state");
 737                         break;
 738                 }
 739         } else {
 740                 struct debug_obj o = { .object = addr,
 741                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 742                                        .descr = descr };
 743
 744                 debug_print_object(&o, "active_state");
 745         }
 746
 747         raw_spin_unlock_irqrestore(&db->lock, flags);
 748 }
 749 EXPORT_SYMBOL_GPL(debug_object_active_state);
 750
 751 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 752 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 753 {
 754         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 755         struct debug_obj_descr *descr;
 756         enum debug_obj_state state;
 757         struct debug_bucket *db;
 758         struct hlist_node *tmp;
 759         struct debug_obj *obj;
 760         int cnt, objs_checked = 0;
 761         bool work = false;
 762
 763         saddr = (unsigned long) address;
 764         eaddr = saddr + size;
 765         paddr = saddr & ODEBUG_CHUNK_MASK;
 766         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 767         chunks >>= ODEBUG_CHUNK_SHIFT;
 768
 769         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 770                 db = get_bucket(paddr);
 771
 772 repeat:
 773                 cnt = 0;
 774                 raw_spin_lock_irqsave(&db->lock, flags);
 775                 hlist_for_each_entry_safe(obj, tmp, &db->list, node) {
 776                         cnt++;
 777                         oaddr = (unsigned long) obj->object;
 778                         if (oaddr < saddr || oaddr >= eaddr)
 779                                 continue;
 780
 781                         switch (obj->state) {
 782                         case ODEBUG_STATE_ACTIVE:
 783                                 debug_print_object(obj, "free");
 784                                 descr = obj->descr;
 785                                 state = obj->state;
 786                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 787                                 debug_object_fixup(descr->fixup_free,
 788                                                    (void *) oaddr, state);
 789                                 goto repeat;
 790                         default:
 791                                 hlist_del(&obj->node);
 792                                 work |= __free_object(obj);
 793                                 break;
 794                         }
 795                 }
 796                 raw_spin_unlock_irqrestore(&db->lock, flags);
 797
 798                 if (cnt > debug_objects_maxchain)
 799                         debug_objects_maxchain = cnt;
 800
 801                 objs_checked += cnt;
 802         }
 803
 804         if (objs_checked > debug_objects_maxchecked)
 805                 debug_objects_maxchecked = objs_checked;
 806
 807         /* Schedule work to actually kmem_cache_free() objects */
 808         if (work)
 809                 schedule_work(&debug_obj_work);
 810 }
 811
 812 void debug_check_no_obj_freed(const void *address, unsigned long size)
 813 {
 814         if (debug_objects_enabled)
 815                 __debug_check_no_obj_freed(address, size);
 816 }
 817 #endif
 818
 819 #ifdef CONFIG_DEBUG_FS
 820
 821 static int debug_stats_show(struct seq_file *m, void *v)
 822 {
 823         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 824         seq_printf(m, "max_checked   :%d\n", debug_objects_maxchecked);
 825         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 826         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 827         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 828         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 829         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 830         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 831         seq_printf(m, "on_free_list  :%d\n", obj_nr_tofree);
 832         seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
 833         seq_printf(m, "objs_freed    :%d\n", debug_objects_freed);
 834         return 0;
 835 }
 836
 837 static int debug_stats_open(struct inode *inode, struct file *filp)
 838 {
 839         return single_open(filp, debug_stats_show, NULL);
 840 }
 841
 842 static const struct file_operations debug_stats_fops = {
 843         .open           = debug_stats_open,
 844         .read           = seq_read,
 845         .llseek         = seq_lseek,
 846         .release        = single_release,
 847 };
 848
 849 static int __init debug_objects_init_debugfs(void)
 850 {
 851         struct dentry *dbgdir, *dbgstats;
 852
 853         if (!debug_objects_enabled)
 854                 return 0;
 855
 856         dbgdir = debugfs_create_dir("debug_objects", NULL);
 857         if (!dbgdir)
 858                 return -ENOMEM;
 859
 860         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 861                                        &debug_stats_fops);
 862         if (!dbgstats)
 863                 goto err;
 864
 865         return 0;
 866
 867 err:
 868         debugfs_remove(dbgdir);
 869
 870         return -ENOMEM;
 871 }
 872 __initcall(debug_objects_init_debugfs);
 873
 874 #else
 875 static inline void debug_objects_init_debugfs(void) { }
 876 #endif
 877
 878 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 879
 880 /* Random data structure for the self test */
 881 struct self_test {
 882         unsigned long   dummy1[6];
 883         int             static_init;
 884         unsigned long   dummy2[3];
 885 };
 886
 887 static __initdata struct debug_obj_descr descr_type_test;
 888
 889 static bool __init is_static_object(void *addr)
 890 {
 891         struct self_test *obj = addr;
 892
 893         return obj->static_init;
 894 }
 895
 896 /*
 897  * fixup_init is called when:
 898  * - an active object is initialized
 899  */
 900 static bool __init fixup_init(void *addr, enum debug_obj_state state)
 901 {
 902         struct self_test *obj = addr;
 903
 904         switch (state) {
 905         case ODEBUG_STATE_ACTIVE:
 906                 debug_object_deactivate(obj, &descr_type_test);
 907                 debug_object_init(obj, &descr_type_test);
 908                 return true;
 909         default:
 910                 return false;
 911         }
 912 }
 913
 914 /*
 915  * fixup_activate is called when:
 916  * - an active object is activated
 917  * - an unknown non-static object is activated
 918  */
 919 static bool __init fixup_activate(void *addr, enum debug_obj_state state)
 920 {
 921         struct self_test *obj = addr;
 922
 923         switch (state) {
 924         case ODEBUG_STATE_NOTAVAILABLE:
 925                 return true;
 926         case ODEBUG_STATE_ACTIVE:
 927                 debug_object_deactivate(obj, &descr_type_test);
 928                 debug_object_activate(obj, &descr_type_test);
 929                 return true;
 930
 931         default:
 932                 return false;
 933         }
 934 }
 935
 936 /*
 937  * fixup_destroy is called when:
 938  * - an active object is destroyed
 939  */
 940 static bool __init fixup_destroy(void *addr, enum debug_obj_state state)
 941 {
 942         struct self_test *obj = addr;
 943
 944         switch (state) {
 945         case ODEBUG_STATE_ACTIVE:
 946                 debug_object_deactivate(obj, &descr_type_test);
 947                 debug_object_destroy(obj, &descr_type_test);
 948                 return true;
 949         default:
 950                 return false;
 951         }
 952 }
 953
 954 /*
 955  * fixup_free is called when:
 956  * - an active object is freed
 957  */
 958 static bool __init fixup_free(void *addr, enum debug_obj_state state)
 959 {
 960         struct self_test *obj = addr;
 961
 962         switch (state) {
 963         case ODEBUG_STATE_ACTIVE:
 964                 debug_object_deactivate(obj, &descr_type_test);
 965                 debug_object_free(obj, &descr_type_test);
 966                 return true;
 967         default:
 968                 return false;
 969         }
 970 }
 971
 972 static int __init
 973 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 974 {
 975         struct debug_bucket *db;
 976         struct debug_obj *obj;
 977         unsigned long flags;
 978         int res = -EINVAL;
 979
 980         db = get_bucket((unsigned long) addr);
 981
 982         raw_spin_lock_irqsave(&db->lock, flags);
 983
 984         obj = lookup_object(addr, db);
 985         if (!obj && state != ODEBUG_STATE_NONE) {
 986                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 987                 goto out;
 988         }
 989         if (obj && obj->state != state) {
 990                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 991                        obj->state, state);
 992                 goto out;
 993         }
 994         if (fixups != debug_objects_fixups) {
 995                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 996                        fixups, debug_objects_fixups);
 997                 goto out;
 998         }
 999         if (warnings != debug_objects_warnings) {
1000                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
1001                        warnings, debug_objects_warnings);
1002                 goto out;
1003         }
1004         res = 0;
1005 out:
1006         raw_spin_unlock_irqrestore(&db->lock, flags);
1007         if (res)
1008                 debug_objects_enabled = 0;
1009         return res;
1010 }
1011
1012 static __initdata struct debug_obj_descr descr_type_test = {
1013         .name                   = "selftest",
1014         .is_static_object       = is_static_object,
1015         .fixup_init             = fixup_init,
1016         .fixup_activate         = fixup_activate,
1017         .fixup_destroy          = fixup_destroy,
1018         .fixup_free             = fixup_free,
1019 };
1020
1021 static __initdata struct self_test obj = { .static_init = 0 };
1022
1023 static void __init debug_objects_selftest(void)
1024 {
1025         int fixups, oldfixups, warnings, oldwarnings;
1026         unsigned long flags;
1027
1028         local_irq_save(flags);
1029
1030         fixups = oldfixups = debug_objects_fixups;
1031         warnings = oldwarnings = debug_objects_warnings;
1032         descr_test = &descr_type_test;
1033
1034         debug_object_init(&obj, &descr_type_test);
1035         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1036                 goto out;
1037         debug_object_activate(&obj, &descr_type_test);
1038         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1039                 goto out;
1040         debug_object_activate(&obj, &descr_type_test);
1041         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
1042                 goto out;
1043         debug_object_deactivate(&obj, &descr_type_test);
1044         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
1045                 goto out;
1046         debug_object_destroy(&obj, &descr_type_test);
1047         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
1048                 goto out;
1049         debug_object_init(&obj, &descr_type_test);
1050         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1051                 goto out;
1052         debug_object_activate(&obj, &descr_type_test);
1053         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1054                 goto out;
1055         debug_object_deactivate(&obj, &descr_type_test);
1056         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
1057                 goto out;
1058         debug_object_free(&obj, &descr_type_test);
1059         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1060                 goto out;
1061
1062         obj.static_init = 1;
1063         debug_object_activate(&obj, &descr_type_test);
1064         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1065                 goto out;
1066         debug_object_init(&obj, &descr_type_test);
1067         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
1068                 goto out;
1069         debug_object_free(&obj, &descr_type_test);
1070         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
1071                 goto out;
1072
1073 #ifdef CONFIG_DEBUG_OBJECTS_FREE
1074         debug_object_init(&obj, &descr_type_test);
1075         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
1076                 goto out;
1077         debug_object_activate(&obj, &descr_type_test);
1078         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
1079                 goto out;
1080         __debug_check_no_obj_freed(&obj, sizeof(obj));
1081         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
1082                 goto out;
1083 #endif
1084         pr_info("selftest passed\n");
1085
1086 out:
1087         debug_objects_fixups = oldfixups;
1088         debug_objects_warnings = oldwarnings;
1089         descr_test = NULL;
1090
1091         local_irq_restore(flags);
1092 }
1093 #else
1094 static inline void debug_objects_selftest(void) { }
1095 #endif
1096
1097 /*
1098  * Called during early boot to initialize the hash buckets and link
1099  * the static object pool objects into the poll list. After this call
1100  * the object tracker is fully operational.
1101  */
1102 void __init debug_objects_early_init(void)
1103 {
1104         int i;
1105
1106         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1107                 raw_spin_lock_init(&obj_hash[i].lock);
1108
1109         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1110                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1111 }
1112
1113 /*
1114  * Convert the statically allocated objects to dynamic ones:
1115  */
1116 static int __init debug_objects_replace_static_objects(void)
1117 {
1118         struct debug_bucket *db = obj_hash;
1119         struct hlist_node *tmp;
1120         struct debug_obj *obj, *new;
1121         HLIST_HEAD(objects);
1122         int i, cnt = 0;
1123
1124         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1125                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1126                 if (!obj)
1127                         goto free;
1128                 kmemleak_ignore(obj);
1129                 hlist_add_head(&obj->node, &objects);
1130         }
1131
1132         /*
1133          * When debug_objects_mem_init() is called we know that only
1134          * one CPU is up, so disabling interrupts is enough
1135          * protection. This avoids the lockdep hell of lock ordering.
1136          */
1137         local_irq_disable();
1138
1139         /* Remove the statically allocated objects from the pool */
1140         hlist_for_each_entry_safe(obj, tmp, &obj_pool, node)
1141                 hlist_del(&obj->node);
1142         /* Move the allocated objects to the pool */
1143         hlist_move_list(&objects, &obj_pool);
1144
1145         /* Replace the active object references */
1146         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1147                 hlist_move_list(&db->list, &objects);
1148
1149                 hlist_for_each_entry(obj, &objects, node) {
1150                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1151                         hlist_del(&new->node);
1152                         /* copy object data */
1153                         *new = *obj;
1154                         hlist_add_head(&new->node, &db->list);
1155                         cnt++;
1156                 }
1157         }
1158         local_irq_enable();
1159
1160         pr_debug("%d of %d active objects replaced\n",
1161                  cnt, obj_pool_used);
1162         return 0;
1163 free:
1164         hlist_for_each_entry_safe(obj, tmp, &objects, node) {
1165                 hlist_del(&obj->node);
1166                 kmem_cache_free(obj_cache, obj);
1167         }
1168         return -ENOMEM;
1169 }
1170
1171 /*
1172  * Called after the kmem_caches are functional to setup a dedicated
1173  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1174  * prevents that the debug code is called on kmem_cache_free() for the
1175  * debug tracker objects to avoid recursive calls.
1176  */
1177 void __init debug_objects_mem_init(void)
1178 {
1179         if (!debug_objects_enabled)
1180                 return;
1181
1182         obj_cache = kmem_cache_create("debug_objects_cache",
1183                                       sizeof (struct debug_obj), 0,
1184                                       SLAB_DEBUG_OBJECTS, NULL);
1185
1186         if (!obj_cache || debug_objects_replace_static_objects()) {
1187                 debug_objects_enabled = 0;
1188                 if (obj_cache)
1189                         kmem_cache_destroy(obj_cache);
1190                 pr_warn("out of memory.\n");
1191         } else
1192                 debug_objects_selftest();
1193
1194         /*
1195          * Increase the thresholds for allocating and freeing objects
1196          * according to the number of possible CPUs available in the system.
1197          */
1198         debug_objects_pool_size += num_possible_cpus() * 32;
1199         debug_objects_pool_min_level += num_possible_cpus() * 4;
1200 }