lib/debugobjects.c

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