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