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 #include <linux/debugobjects.h>
  11 #include <linux/interrupt.h>
  12 #include <linux/seq_file.h>
  13 #include <linux/debugfs.h>
  14 #include <linux/hash.h>
  15
  16 #define ODEBUG_HASH_BITS        14
  17 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  18
  19 #define ODEBUG_POOL_SIZE        512
  20 #define ODEBUG_POOL_MIN_LEVEL   256
  21
  22 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  23 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  24 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  25
  26 struct debug_bucket {
  27         struct hlist_head       list;
  28         spinlock_t              lock;
  29 };
  30
  31 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  32
  33 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE];
  34
  35 static DEFINE_SPINLOCK(pool_lock);
  36
  37 static HLIST_HEAD(obj_pool);
  38
  39 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  40 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  41 static int                      obj_pool_used;
  42 static int                      obj_pool_max_used;
  43 static struct kmem_cache        *obj_cache;
  44
  45 static int                      debug_objects_maxchain __read_mostly;
  46 static int                      debug_objects_fixups __read_mostly;
  47 static int                      debug_objects_warnings __read_mostly;
  48 static int                      debug_objects_enabled __read_mostly
  49                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  50
  51 static struct debug_obj_descr   *descr_test  __read_mostly;
  52
  53 static int __init enable_object_debug(char *str)
  54 {
  55         debug_objects_enabled = 1;
  56         return 0;
  57 }
  58 early_param("debug_objects", enable_object_debug);
  59
  60 static const char *obj_states[ODEBUG_STATE_MAX] = {
  61         [ODEBUG_STATE_NONE]             = "none",
  62         [ODEBUG_STATE_INIT]             = "initialized",
  63         [ODEBUG_STATE_INACTIVE]         = "inactive",
  64         [ODEBUG_STATE_ACTIVE]           = "active",
  65         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  66         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  67 };
  68
  69 static int fill_pool(void)
  70 {
  71         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  72         struct debug_obj *new;
  73         unsigned long flags;
  74
  75         if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
  76                 return obj_pool_free;
  77
  78         if (unlikely(!obj_cache))
  79                 return obj_pool_free;
  80
  81         while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
  82
  83                 new = kmem_cache_zalloc(obj_cache, gfp);
  84                 if (!new)
  85                         return obj_pool_free;
  86
  87                 spin_lock_irqsave(&pool_lock, flags);
  88                 hlist_add_head(&new->node, &obj_pool);
  89                 obj_pool_free++;
  90                 spin_unlock_irqrestore(&pool_lock, flags);
  91         }
  92         return obj_pool_free;
  93 }
  94
  95 /*
  96  * Lookup an object in the hash bucket.
  97  */
  98 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
  99 {
 100         struct hlist_node *node;
 101         struct debug_obj *obj;
 102         int cnt = 0;
 103
 104         hlist_for_each_entry(obj, node, &b->list, node) {
 105                 cnt++;
 106                 if (obj->object == addr)
 107                         return obj;
 108         }
 109         if (cnt > debug_objects_maxchain)
 110                 debug_objects_maxchain = cnt;
 111
 112         return NULL;
 113 }
 114
 115 /*
 116  * Allocate a new object. If the pool is empty, switch off the debugger.
 117  * Must be called with interrupts disabled.
 118  */
 119 static struct debug_obj *
 120 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 121 {
 122         struct debug_obj *obj = NULL;
 123
 124         spin_lock(&pool_lock);
 125         if (obj_pool.first) {
 126                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 127
 128                 obj->object = addr;
 129                 obj->descr  = descr;
 130                 obj->state  = ODEBUG_STATE_NONE;
 131                 hlist_del(&obj->node);
 132
 133                 hlist_add_head(&obj->node, &b->list);
 134
 135                 obj_pool_used++;
 136                 if (obj_pool_used > obj_pool_max_used)
 137                         obj_pool_max_used = obj_pool_used;
 138
 139                 obj_pool_free--;
 140                 if (obj_pool_free < obj_pool_min_free)
 141                         obj_pool_min_free = obj_pool_free;
 142         }
 143         spin_unlock(&pool_lock);
 144
 145         return obj;
 146 }
 147
 148 /*
 149  * Put the object back into the pool or give it back to kmem_cache:
 150  */
 151 static void free_object(struct debug_obj *obj)
 152 {
 153         unsigned long idx = (unsigned long)(obj - obj_static_pool);
 154         unsigned long flags;
 155
 156         if (obj_pool_free < ODEBUG_POOL_SIZE || idx < ODEBUG_POOL_SIZE) {
 157                 spin_lock_irqsave(&pool_lock, flags);
 158                 hlist_add_head(&obj->node, &obj_pool);
 159                 obj_pool_free++;
 160                 obj_pool_used--;
 161                 spin_unlock_irqrestore(&pool_lock, flags);
 162         } else {
 163                 spin_lock_irqsave(&pool_lock, flags);
 164                 obj_pool_used--;
 165                 spin_unlock_irqrestore(&pool_lock, flags);
 166                 kmem_cache_free(obj_cache, obj);
 167         }
 168 }
 169
 170 /*
 171  * We run out of memory. That means we probably have tons of objects
 172  * allocated.
 173  */
 174 static void debug_objects_oom(void)
 175 {
 176         struct debug_bucket *db = obj_hash;
 177         struct hlist_node *node, *tmp;
 178         HLIST_HEAD(freelist);
 179         struct debug_obj *obj;
 180         unsigned long flags;
 181         int i;
 182
 183         printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");
 184
 185         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 186                 spin_lock_irqsave(&db->lock, flags);
 187                 hlist_move_list(&db->list, &freelist);
 188                 spin_unlock_irqrestore(&db->lock, flags);
 189
 190                 /* Now free them */
 191                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 192                         hlist_del(&obj->node);
 193                         free_object(obj);
 194                 }
 195         }
 196 }
 197
 198 /*
 199  * We use the pfn of the address for the hash. That way we can check
 200  * for freed objects simply by checking the affected bucket.
 201  */
 202 static struct debug_bucket *get_bucket(unsigned long addr)
 203 {
 204         unsigned long hash;
 205
 206         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 207         return &obj_hash[hash];
 208 }
 209
 210 static void debug_print_object(struct debug_obj *obj, char *msg)
 211 {
 212         static int limit;
 213
 214         if (limit < 5 && obj->descr != descr_test) {
 215                 limit++;
 216                 WARN(1, KERN_ERR "ODEBUG: %s %s object type: %s\n", msg,
 217                        obj_states[obj->state], obj->descr->name);
 218         }
 219         debug_objects_warnings++;
 220 }
 221
 222 /*
 223  * Try to repair the damage, so we have a better chance to get useful
 224  * debug output.
 225  */
 226 static void
 227 debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
 228                    void * addr, enum debug_obj_state state)
 229 {
 230         if (fixup)
 231                 debug_objects_fixups += fixup(addr, state);
 232 }
 233
 234 static void debug_object_is_on_stack(void *addr, int onstack)
 235 {
 236         int is_on_stack;
 237         static int limit;
 238
 239         if (limit > 4)
 240                 return;
 241
 242         is_on_stack = object_is_on_stack(addr);
 243         if (is_on_stack == onstack)
 244                 return;
 245
 246         limit++;
 247         if (is_on_stack)
 248                 printk(KERN_WARNING
 249                        "ODEBUG: object is on stack, but not annotated\n");
 250         else
 251                 printk(KERN_WARNING
 252                        "ODEBUG: object is not on stack, but annotated\n");
 253         WARN_ON(1);
 254 }
 255
 256 static void
 257 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 258 {
 259         enum debug_obj_state state;
 260         struct debug_bucket *db;
 261         struct debug_obj *obj;
 262         unsigned long flags;
 263
 264         fill_pool();
 265
 266         db = get_bucket((unsigned long) addr);
 267
 268         spin_lock_irqsave(&db->lock, flags);
 269
 270         obj = lookup_object(addr, db);
 271         if (!obj) {
 272                 obj = alloc_object(addr, db, descr);
 273                 if (!obj) {
 274                         debug_objects_enabled = 0;
 275                         spin_unlock_irqrestore(&db->lock, flags);
 276                         debug_objects_oom();
 277                         return;
 278                 }
 279                 debug_object_is_on_stack(addr, onstack);
 280         }
 281
 282         switch (obj->state) {
 283         case ODEBUG_STATE_NONE:
 284         case ODEBUG_STATE_INIT:
 285         case ODEBUG_STATE_INACTIVE:
 286                 obj->state = ODEBUG_STATE_INIT;
 287                 break;
 288
 289         case ODEBUG_STATE_ACTIVE:
 290                 debug_print_object(obj, "init");
 291                 state = obj->state;
 292                 spin_unlock_irqrestore(&db->lock, flags);
 293                 debug_object_fixup(descr->fixup_init, addr, state);
 294                 return;
 295
 296         case ODEBUG_STATE_DESTROYED:
 297                 debug_print_object(obj, "init");
 298                 break;
 299         default:
 300                 break;
 301         }
 302
 303         spin_unlock_irqrestore(&db->lock, flags);
 304 }
 305
 306 /**
 307  * debug_object_init - debug checks when an object is initialized
 308  * @addr:       address of the object
 309  * @descr:      pointer to an object specific debug description structure
 310  */
 311 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 312 {
 313         if (!debug_objects_enabled)
 314                 return;
 315
 316         __debug_object_init(addr, descr, 0);
 317 }
 318
 319 /**
 320  * debug_object_init_on_stack - debug checks when an object on stack is
 321  *                              initialized
 322  * @addr:       address of the object
 323  * @descr:      pointer to an object specific debug description structure
 324  */
 325 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 326 {
 327         if (!debug_objects_enabled)
 328                 return;
 329
 330         __debug_object_init(addr, descr, 1);
 331 }
 332
 333 /**
 334  * debug_object_activate - debug checks when an object is activated
 335  * @addr:       address of the object
 336  * @descr:      pointer to an object specific debug description structure
 337  */
 338 void debug_object_activate(void *addr, struct debug_obj_descr *descr)
 339 {
 340         enum debug_obj_state state;
 341         struct debug_bucket *db;
 342         struct debug_obj *obj;
 343         unsigned long flags;
 344
 345         if (!debug_objects_enabled)
 346                 return;
 347
 348         db = get_bucket((unsigned long) addr);
 349
 350         spin_lock_irqsave(&db->lock, flags);
 351
 352         obj = lookup_object(addr, db);
 353         if (obj) {
 354                 switch (obj->state) {
 355                 case ODEBUG_STATE_INIT:
 356                 case ODEBUG_STATE_INACTIVE:
 357                         obj->state = ODEBUG_STATE_ACTIVE;
 358                         break;
 359
 360                 case ODEBUG_STATE_ACTIVE:
 361                         debug_print_object(obj, "activate");
 362                         state = obj->state;
 363                         spin_unlock_irqrestore(&db->lock, flags);
 364                         debug_object_fixup(descr->fixup_activate, addr, state);
 365                         return;
 366
 367                 case ODEBUG_STATE_DESTROYED:
 368                         debug_print_object(obj, "activate");
 369                         break;
 370                 default:
 371                         break;
 372                 }
 373                 spin_unlock_irqrestore(&db->lock, flags);
 374                 return;
 375         }
 376
 377         spin_unlock_irqrestore(&db->lock, flags);
 378         /*
 379          * This happens when a static object is activated. We
 380          * let the type specific code decide whether this is
 381          * true or not.
 382          */
 383         debug_object_fixup(descr->fixup_activate, addr,
 384                            ODEBUG_STATE_NOTAVAILABLE);
 385 }
 386
 387 /**
 388  * debug_object_deactivate - debug checks when an object is deactivated
 389  * @addr:       address of the object
 390  * @descr:      pointer to an object specific debug description structure
 391  */
 392 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 393 {
 394         struct debug_bucket *db;
 395         struct debug_obj *obj;
 396         unsigned long flags;
 397
 398         if (!debug_objects_enabled)
 399                 return;
 400
 401         db = get_bucket((unsigned long) addr);
 402
 403         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                 case ODEBUG_STATE_ACTIVE:
 411                         obj->state = ODEBUG_STATE_INACTIVE;
 412                         break;
 413
 414                 case ODEBUG_STATE_DESTROYED:
 415                         debug_print_object(obj, "deactivate");
 416                         break;
 417                 default:
 418                         break;
 419                 }
 420         } else {
 421                 struct debug_obj o = { .object = addr,
 422                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 423                                        .descr = descr };
 424
 425                 debug_print_object(&o, "deactivate");
 426         }
 427
 428         spin_unlock_irqrestore(&db->lock, flags);
 429 }
 430
 431 /**
 432  * debug_object_destroy - debug checks when an object is destroyed
 433  * @addr:       address of the object
 434  * @descr:      pointer to an object specific debug description structure
 435  */
 436 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 437 {
 438         enum debug_obj_state state;
 439         struct debug_bucket *db;
 440         struct debug_obj *obj;
 441         unsigned long flags;
 442
 443         if (!debug_objects_enabled)
 444                 return;
 445
 446         db = get_bucket((unsigned long) addr);
 447
 448         spin_lock_irqsave(&db->lock, flags);
 449
 450         obj = lookup_object(addr, db);
 451         if (!obj)
 452                 goto out_unlock;
 453
 454         switch (obj->state) {
 455         case ODEBUG_STATE_NONE:
 456         case ODEBUG_STATE_INIT:
 457         case ODEBUG_STATE_INACTIVE:
 458                 obj->state = ODEBUG_STATE_DESTROYED;
 459                 break;
 460         case ODEBUG_STATE_ACTIVE:
 461                 debug_print_object(obj, "destroy");
 462                 state = obj->state;
 463                 spin_unlock_irqrestore(&db->lock, flags);
 464                 debug_object_fixup(descr->fixup_destroy, addr, state);
 465                 return;
 466
 467         case ODEBUG_STATE_DESTROYED:
 468                 debug_print_object(obj, "destroy");
 469                 break;
 470         default:
 471                 break;
 472         }
 473 out_unlock:
 474         spin_unlock_irqrestore(&db->lock, flags);
 475 }
 476
 477 /**
 478  * debug_object_free - debug checks when an object is freed
 479  * @addr:       address of the object
 480  * @descr:      pointer to an object specific debug description structure
 481  */
 482 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 483 {
 484         enum debug_obj_state state;
 485         struct debug_bucket *db;
 486         struct debug_obj *obj;
 487         unsigned long flags;
 488
 489         if (!debug_objects_enabled)
 490                 return;
 491
 492         db = get_bucket((unsigned long) addr);
 493
 494         spin_lock_irqsave(&db->lock, flags);
 495
 496         obj = lookup_object(addr, db);
 497         if (!obj)
 498                 goto out_unlock;
 499
 500         switch (obj->state) {
 501         case ODEBUG_STATE_ACTIVE:
 502                 debug_print_object(obj, "free");
 503                 state = obj->state;
 504                 spin_unlock_irqrestore(&db->lock, flags);
 505                 debug_object_fixup(descr->fixup_free, addr, state);
 506                 return;
 507         default:
 508                 hlist_del(&obj->node);
 509                 spin_unlock_irqrestore(&db->lock, flags);
 510                 free_object(obj);
 511                 return;
 512         }
 513 out_unlock:
 514         spin_unlock_irqrestore(&db->lock, flags);
 515 }
 516
 517 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 518 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 519 {
 520         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 521         struct hlist_node *node, *tmp;
 522         HLIST_HEAD(freelist);
 523         struct debug_obj_descr *descr;
 524         enum debug_obj_state state;
 525         struct debug_bucket *db;
 526         struct debug_obj *obj;
 527         int cnt;
 528
 529         saddr = (unsigned long) address;
 530         eaddr = saddr + size;
 531         paddr = saddr & ODEBUG_CHUNK_MASK;
 532         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 533         chunks >>= ODEBUG_CHUNK_SHIFT;
 534
 535         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 536                 db = get_bucket(paddr);
 537
 538 repeat:
 539                 cnt = 0;
 540                 spin_lock_irqsave(&db->lock, flags);
 541                 hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
 542                         cnt++;
 543                         oaddr = (unsigned long) obj->object;
 544                         if (oaddr < saddr || oaddr >= eaddr)
 545                                 continue;
 546
 547                         switch (obj->state) {
 548                         case ODEBUG_STATE_ACTIVE:
 549                                 debug_print_object(obj, "free");
 550                                 descr = obj->descr;
 551                                 state = obj->state;
 552                                 spin_unlock_irqrestore(&db->lock, flags);
 553                                 debug_object_fixup(descr->fixup_free,
 554                                                    (void *) oaddr, state);
 555                                 goto repeat;
 556                         default:
 557                                 hlist_del(&obj->node);
 558                                 hlist_add_head(&obj->node, &freelist);
 559                                 break;
 560                         }
 561                 }
 562                 spin_unlock_irqrestore(&db->lock, flags);
 563
 564                 /* Now free them */
 565                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 566                         hlist_del(&obj->node);
 567                         free_object(obj);
 568                 }
 569
 570                 if (cnt > debug_objects_maxchain)
 571                         debug_objects_maxchain = cnt;
 572         }
 573 }
 574
 575 void debug_check_no_obj_freed(const void *address, unsigned long size)
 576 {
 577         if (debug_objects_enabled)
 578                 __debug_check_no_obj_freed(address, size);
 579 }
 580 #endif
 581
 582 #ifdef CONFIG_DEBUG_FS
 583
 584 static int debug_stats_show(struct seq_file *m, void *v)
 585 {
 586         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 587         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 588         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 589         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 590         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 591         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 592         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 593         return 0;
 594 }
 595
 596 static int debug_stats_open(struct inode *inode, struct file *filp)
 597 {
 598         return single_open(filp, debug_stats_show, NULL);
 599 }
 600
 601 static const struct file_operations debug_stats_fops = {
 602         .open           = debug_stats_open,
 603         .read           = seq_read,
 604         .llseek         = seq_lseek,
 605         .release        = single_release,
 606 };
 607
 608 static int __init debug_objects_init_debugfs(void)
 609 {
 610         struct dentry *dbgdir, *dbgstats;
 611
 612         if (!debug_objects_enabled)
 613                 return 0;
 614
 615         dbgdir = debugfs_create_dir("debug_objects", NULL);
 616         if (!dbgdir)
 617                 return -ENOMEM;
 618
 619         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 620                                        &debug_stats_fops);
 621         if (!dbgstats)
 622                 goto err;
 623
 624         return 0;
 625
 626 err:
 627         debugfs_remove(dbgdir);
 628
 629         return -ENOMEM;
 630 }
 631 __initcall(debug_objects_init_debugfs);
 632
 633 #else
 634 static inline void debug_objects_init_debugfs(void) { }
 635 #endif
 636
 637 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 638
 639 /* Random data structure for the self test */
 640 struct self_test {
 641         unsigned long   dummy1[6];
 642         int             static_init;
 643         unsigned long   dummy2[3];
 644 };
 645
 646 static __initdata struct debug_obj_descr descr_type_test;
 647
 648 /*
 649  * fixup_init is called when:
 650  * - an active object is initialized
 651  */
 652 static int __init fixup_init(void *addr, enum debug_obj_state state)
 653 {
 654         struct self_test *obj = addr;
 655
 656         switch (state) {
 657         case ODEBUG_STATE_ACTIVE:
 658                 debug_object_deactivate(obj, &descr_type_test);
 659                 debug_object_init(obj, &descr_type_test);
 660                 return 1;
 661         default:
 662                 return 0;
 663         }
 664 }
 665
 666 /*
 667  * fixup_activate is called when:
 668  * - an active object is activated
 669  * - an unknown object is activated (might be a statically initialized object)
 670  */
 671 static int __init fixup_activate(void *addr, enum debug_obj_state state)
 672 {
 673         struct self_test *obj = addr;
 674
 675         switch (state) {
 676         case ODEBUG_STATE_NOTAVAILABLE:
 677                 if (obj->static_init == 1) {
 678                         debug_object_init(obj, &descr_type_test);
 679                         debug_object_activate(obj, &descr_type_test);
 680                         /*
 681                          * Real code should return 0 here ! This is
 682                          * not a fixup of some bad behaviour. We
 683                          * merily call the debug_init function to keep
 684                          * track of the object.
 685                          */
 686                         return 1;
 687                 } else {
 688                         /* Real code needs to emit a warning here */
 689                 }
 690                 return 0;
 691
 692         case ODEBUG_STATE_ACTIVE:
 693                 debug_object_deactivate(obj, &descr_type_test);
 694                 debug_object_activate(obj, &descr_type_test);
 695                 return 1;
 696
 697         default:
 698                 return 0;
 699         }
 700 }
 701
 702 /*
 703  * fixup_destroy is called when:
 704  * - an active object is destroyed
 705  */
 706 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
 707 {
 708         struct self_test *obj = addr;
 709
 710         switch (state) {
 711         case ODEBUG_STATE_ACTIVE:
 712                 debug_object_deactivate(obj, &descr_type_test);
 713                 debug_object_destroy(obj, &descr_type_test);
 714                 return 1;
 715         default:
 716                 return 0;
 717         }
 718 }
 719
 720 /*
 721  * fixup_free is called when:
 722  * - an active object is freed
 723  */
 724 static int __init fixup_free(void *addr, enum debug_obj_state state)
 725 {
 726         struct self_test *obj = addr;
 727
 728         switch (state) {
 729         case ODEBUG_STATE_ACTIVE:
 730                 debug_object_deactivate(obj, &descr_type_test);
 731                 debug_object_free(obj, &descr_type_test);
 732                 return 1;
 733         default:
 734                 return 0;
 735         }
 736 }
 737
 738 static int
 739 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 740 {
 741         struct debug_bucket *db;
 742         struct debug_obj *obj;
 743         unsigned long flags;
 744         int res = -EINVAL;
 745
 746         db = get_bucket((unsigned long) addr);
 747
 748         spin_lock_irqsave(&db->lock, flags);
 749
 750         obj = lookup_object(addr, db);
 751         if (!obj && state != ODEBUG_STATE_NONE) {
 752                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 753                 goto out;
 754         }
 755         if (obj && obj->state != state) {
 756                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 757                        obj->state, state);
 758                 goto out;
 759         }
 760         if (fixups != debug_objects_fixups) {
 761                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 762                        fixups, debug_objects_fixups);
 763                 goto out;
 764         }
 765         if (warnings != debug_objects_warnings) {
 766                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 767                        warnings, debug_objects_warnings);
 768                 goto out;
 769         }
 770         res = 0;
 771 out:
 772         spin_unlock_irqrestore(&db->lock, flags);
 773         if (res)
 774                 debug_objects_enabled = 0;
 775         return res;
 776 }
 777
 778 static __initdata struct debug_obj_descr descr_type_test = {
 779         .name                   = "selftest",
 780         .fixup_init             = fixup_init,
 781         .fixup_activate         = fixup_activate,
 782         .fixup_destroy          = fixup_destroy,
 783         .fixup_free             = fixup_free,
 784 };
 785
 786 static __initdata struct self_test obj = { .static_init = 0 };
 787
 788 static void __init debug_objects_selftest(void)
 789 {
 790         int fixups, oldfixups, warnings, oldwarnings;
 791         unsigned long flags;
 792
 793         local_irq_save(flags);
 794
 795         fixups = oldfixups = debug_objects_fixups;
 796         warnings = oldwarnings = debug_objects_warnings;
 797         descr_test = &descr_type_test;
 798
 799         debug_object_init(&obj, &descr_type_test);
 800         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 801                 goto out;
 802         debug_object_activate(&obj, &descr_type_test);
 803         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 804                 goto out;
 805         debug_object_activate(&obj, &descr_type_test);
 806         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 807                 goto out;
 808         debug_object_deactivate(&obj, &descr_type_test);
 809         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 810                 goto out;
 811         debug_object_destroy(&obj, &descr_type_test);
 812         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 813                 goto out;
 814         debug_object_init(&obj, &descr_type_test);
 815         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 816                 goto out;
 817         debug_object_activate(&obj, &descr_type_test);
 818         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 819                 goto out;
 820         debug_object_deactivate(&obj, &descr_type_test);
 821         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 822                 goto out;
 823         debug_object_free(&obj, &descr_type_test);
 824         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 825                 goto out;
 826
 827         obj.static_init = 1;
 828         debug_object_activate(&obj, &descr_type_test);
 829         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, warnings))
 830                 goto out;
 831         debug_object_init(&obj, &descr_type_test);
 832         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
 833                 goto out;
 834         debug_object_free(&obj, &descr_type_test);
 835         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 836                 goto out;
 837
 838 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 839         debug_object_init(&obj, &descr_type_test);
 840         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 841                 goto out;
 842         debug_object_activate(&obj, &descr_type_test);
 843         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 844                 goto out;
 845         __debug_check_no_obj_freed(&obj, sizeof(obj));
 846         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
 847                 goto out;
 848 #endif
 849         printk(KERN_INFO "ODEBUG: selftest passed\n");
 850
 851 out:
 852         debug_objects_fixups = oldfixups;
 853         debug_objects_warnings = oldwarnings;
 854         descr_test = NULL;
 855
 856         local_irq_restore(flags);
 857 }
 858 #else
 859 static inline void debug_objects_selftest(void) { }
 860 #endif
 861
 862 /*
 863  * Called during early boot to initialize the hash buckets and link
 864  * the static object pool objects into the poll list. After this call
 865  * the object tracker is fully operational.
 866  */
 867 void __init debug_objects_early_init(void)
 868 {
 869         int i;
 870
 871         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
 872                 spin_lock_init(&obj_hash[i].lock);
 873
 874         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
 875                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
 876 }
 877
 878 /*
 879  * Called after the kmem_caches are functional to setup a dedicated
 880  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
 881  * prevents that the debug code is called on kmem_cache_free() for the
 882  * debug tracker objects to avoid recursive calls.
 883  */
 884 void __init debug_objects_mem_init(void)
 885 {
 886         if (!debug_objects_enabled)
 887                 return;
 888
 889         obj_cache = kmem_cache_create("debug_objects_cache",
 890                                       sizeof (struct debug_obj), 0,
 891                                       SLAB_DEBUG_OBJECTS, NULL);
 892
 893         if (!obj_cache)
 894                 debug_objects_enabled = 0;
 895         else
 896                 debug_objects_selftest();
 897 }