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/sched.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/debugfs.h>
  15 #include <linux/hash.h>
  16
  17 #define ODEBUG_HASH_BITS        14
  18 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  19
  20 #define ODEBUG_POOL_SIZE        512
  21 #define ODEBUG_POOL_MIN_LEVEL   256
  22
  23 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  24 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  25 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  26
  27 struct debug_bucket {
  28         struct hlist_head       list;
  29         raw_spinlock_t          lock;
  30 };
  31
  32 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  33
  34 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  35
  36 static DEFINE_RAW_SPINLOCK(pool_lock);
  37
  38 static HLIST_HEAD(obj_pool);
  39
  40 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  41 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  42 static int                      obj_pool_used;
  43 static int                      obj_pool_max_used;
  44 static struct kmem_cache        *obj_cache;
  45
  46 static int                      debug_objects_maxchain __read_mostly;
  47 static int                      debug_objects_fixups __read_mostly;
  48 static int                      debug_objects_warnings __read_mostly;
  49 static int                      debug_objects_enabled __read_mostly
  50                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  51
  52 static struct debug_obj_descr   *descr_test  __read_mostly;
  53
  54 static void free_obj_work(struct work_struct *work);
  55 static DECLARE_WORK(debug_obj_work, free_obj_work);
  56
  57 static int __init enable_object_debug(char *str)
  58 {
  59         debug_objects_enabled = 1;
  60         return 0;
  61 }
  62
  63 static int __init disable_object_debug(char *str)
  64 {
  65         debug_objects_enabled = 0;
  66         return 0;
  67 }
  68
  69 early_param("debug_objects", enable_object_debug);
  70 early_param("no_debug_objects", disable_object_debug);
  71
  72 static const char *obj_states[ODEBUG_STATE_MAX] = {
  73         [ODEBUG_STATE_NONE]             = "none",
  74         [ODEBUG_STATE_INIT]             = "initialized",
  75         [ODEBUG_STATE_INACTIVE]         = "inactive",
  76         [ODEBUG_STATE_ACTIVE]           = "active",
  77         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  78         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  79 };
  80
  81 static int fill_pool(void)
  82 {
  83         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  84         struct debug_obj *new;
  85         unsigned long flags;
  86
  87         if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
  88                 return obj_pool_free;
  89
  90         if (unlikely(!obj_cache))
  91                 return obj_pool_free;
  92
  93         while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
  94
  95                 new = kmem_cache_zalloc(obj_cache, gfp);
  96                 if (!new)
  97                         return obj_pool_free;
  98
  99                 raw_spin_lock_irqsave(&pool_lock, flags);
 100                 hlist_add_head(&new->node, &obj_pool);
 101                 obj_pool_free++;
 102                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 103         }
 104         return obj_pool_free;
 105 }
 106
 107 /*
 108  * Lookup an object in the hash bucket.
 109  */
 110 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 111 {
 112         struct hlist_node *node;
 113         struct debug_obj *obj;
 114         int cnt = 0;
 115
 116         hlist_for_each_entry(obj, node, &b->list, node) {
 117                 cnt++;
 118                 if (obj->object == addr)
 119                         return obj;
 120         }
 121         if (cnt > debug_objects_maxchain)
 122                 debug_objects_maxchain = cnt;
 123
 124         return NULL;
 125 }
 126
 127 /*
 128  * Allocate a new object. If the pool is empty, switch off the debugger.
 129  * Must be called with interrupts disabled.
 130  */
 131 static struct debug_obj *
 132 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 133 {
 134         struct debug_obj *obj = NULL;
 135
 136         raw_spin_lock(&pool_lock);
 137         if (obj_pool.first) {
 138                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 139
 140                 obj->object = addr;
 141                 obj->descr  = descr;
 142                 obj->state  = ODEBUG_STATE_NONE;
 143                 hlist_del(&obj->node);
 144
 145                 hlist_add_head(&obj->node, &b->list);
 146
 147                 obj_pool_used++;
 148                 if (obj_pool_used > obj_pool_max_used)
 149                         obj_pool_max_used = obj_pool_used;
 150
 151                 obj_pool_free--;
 152                 if (obj_pool_free < obj_pool_min_free)
 153                         obj_pool_min_free = obj_pool_free;
 154         }
 155         raw_spin_unlock(&pool_lock);
 156
 157         return obj;
 158 }
 159
 160 /*
 161  * workqueue function to free objects.
 162  */
 163 static void free_obj_work(struct work_struct *work)
 164 {
 165         struct debug_obj *obj;
 166         unsigned long flags;
 167
 168         raw_spin_lock_irqsave(&pool_lock, flags);
 169         while (obj_pool_free > ODEBUG_POOL_SIZE) {
 170                 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
 171                 hlist_del(&obj->node);
 172                 obj_pool_free--;
 173                 /*
 174                  * We release pool_lock across kmem_cache_free() to
 175                  * avoid contention on pool_lock.
 176                  */
 177                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 178                 kmem_cache_free(obj_cache, obj);
 179                 raw_spin_lock_irqsave(&pool_lock, flags);
 180         }
 181         raw_spin_unlock_irqrestore(&pool_lock, flags);
 182 }
 183
 184 /*
 185  * Put the object back into the pool and schedule work to free objects
 186  * if necessary.
 187  */
 188 static void free_object(struct debug_obj *obj)
 189 {
 190         unsigned long flags;
 191         int sched = 0;
 192
 193         raw_spin_lock_irqsave(&pool_lock, flags);
 194         /*
 195          * schedule work when the pool is filled and the cache is
 196          * initialized:
 197          */
 198         if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
 199                 sched = !work_pending(&debug_obj_work);
 200         hlist_add_head(&obj->node, &obj_pool);
 201         obj_pool_free++;
 202         obj_pool_used--;
 203         raw_spin_unlock_irqrestore(&pool_lock, flags);
 204         if (sched)
 205                 schedule_work(&debug_obj_work);
 206 }
 207
 208 /*
 209  * We run out of memory. That means we probably have tons of objects
 210  * allocated.
 211  */
 212 static void debug_objects_oom(void)
 213 {
 214         struct debug_bucket *db = obj_hash;
 215         struct hlist_node *node, *tmp;
 216         HLIST_HEAD(freelist);
 217         struct debug_obj *obj;
 218         unsigned long flags;
 219         int i;
 220
 221         printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");
 222
 223         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 224                 raw_spin_lock_irqsave(&db->lock, flags);
 225                 hlist_move_list(&db->list, &freelist);
 226                 raw_spin_unlock_irqrestore(&db->lock, flags);
 227
 228                 /* Now free them */
 229                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 230                         hlist_del(&obj->node);
 231                         free_object(obj);
 232                 }
 233         }
 234 }
 235
 236 /*
 237  * We use the pfn of the address for the hash. That way we can check
 238  * for freed objects simply by checking the affected bucket.
 239  */
 240 static struct debug_bucket *get_bucket(unsigned long addr)
 241 {
 242         unsigned long hash;
 243
 244         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 245         return &obj_hash[hash];
 246 }
 247
 248 static void debug_print_object(struct debug_obj *obj, char *msg)
 249 {
 250         static int limit;
 251
 252         if (limit < 5 && obj->descr != descr_test) {
 253                 limit++;
 254                 WARN(1, KERN_ERR "ODEBUG: %s %s object type: %s\n", msg,
 255                        obj_states[obj->state], obj->descr->name);
 256         }
 257         debug_objects_warnings++;
 258 }
 259
 260 /*
 261  * Try to repair the damage, so we have a better chance to get useful
 262  * debug output.
 263  */
 264 static void
 265 debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
 266                    void * addr, enum debug_obj_state state)
 267 {
 268         if (fixup)
 269                 debug_objects_fixups += fixup(addr, state);
 270 }
 271
 272 static void debug_object_is_on_stack(void *addr, int onstack)
 273 {
 274         int is_on_stack;
 275         static int limit;
 276
 277         if (limit > 4)
 278                 return;
 279
 280         is_on_stack = object_is_on_stack(addr);
 281         if (is_on_stack == onstack)
 282                 return;
 283
 284         limit++;
 285         if (is_on_stack)
 286                 printk(KERN_WARNING
 287                        "ODEBUG: object is on stack, but not annotated\n");
 288         else
 289                 printk(KERN_WARNING
 290                        "ODEBUG: object is not on stack, but annotated\n");
 291         WARN_ON(1);
 292 }
 293
 294 static void
 295 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 296 {
 297         enum debug_obj_state state;
 298         struct debug_bucket *db;
 299         struct debug_obj *obj;
 300         unsigned long flags;
 301
 302         fill_pool();
 303
 304         db = get_bucket((unsigned long) addr);
 305
 306         raw_spin_lock_irqsave(&db->lock, flags);
 307
 308         obj = lookup_object(addr, db);
 309         if (!obj) {
 310                 obj = alloc_object(addr, db, descr);
 311                 if (!obj) {
 312                         debug_objects_enabled = 0;
 313                         raw_spin_unlock_irqrestore(&db->lock, flags);
 314                         debug_objects_oom();
 315                         return;
 316                 }
 317                 debug_object_is_on_stack(addr, onstack);
 318         }
 319
 320         switch (obj->state) {
 321         case ODEBUG_STATE_NONE:
 322         case ODEBUG_STATE_INIT:
 323         case ODEBUG_STATE_INACTIVE:
 324                 obj->state = ODEBUG_STATE_INIT;
 325                 break;
 326
 327         case ODEBUG_STATE_ACTIVE:
 328                 debug_print_object(obj, "init");
 329                 state = obj->state;
 330                 raw_spin_unlock_irqrestore(&db->lock, flags);
 331                 debug_object_fixup(descr->fixup_init, addr, state);
 332                 return;
 333
 334         case ODEBUG_STATE_DESTROYED:
 335                 debug_print_object(obj, "init");
 336                 break;
 337         default:
 338                 break;
 339         }
 340
 341         raw_spin_unlock_irqrestore(&db->lock, flags);
 342 }
 343
 344 /**
 345  * debug_object_init - debug checks when an object is initialized
 346  * @addr:       address of the object
 347  * @descr:      pointer to an object specific debug description structure
 348  */
 349 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 350 {
 351         if (!debug_objects_enabled)
 352                 return;
 353
 354         __debug_object_init(addr, descr, 0);
 355 }
 356
 357 /**
 358  * debug_object_init_on_stack - debug checks when an object on stack is
 359  *                              initialized
 360  * @addr:       address of the object
 361  * @descr:      pointer to an object specific debug description structure
 362  */
 363 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 364 {
 365         if (!debug_objects_enabled)
 366                 return;
 367
 368         __debug_object_init(addr, descr, 1);
 369 }
 370
 371 /**
 372  * debug_object_activate - debug checks when an object is activated
 373  * @addr:       address of the object
 374  * @descr:      pointer to an object specific debug description structure
 375  */
 376 void debug_object_activate(void *addr, struct debug_obj_descr *descr)
 377 {
 378         enum debug_obj_state state;
 379         struct debug_bucket *db;
 380         struct debug_obj *obj;
 381         unsigned long flags;
 382
 383         if (!debug_objects_enabled)
 384                 return;
 385
 386         db = get_bucket((unsigned long) addr);
 387
 388         raw_spin_lock_irqsave(&db->lock, flags);
 389
 390         obj = lookup_object(addr, db);
 391         if (obj) {
 392                 switch (obj->state) {
 393                 case ODEBUG_STATE_INIT:
 394                 case ODEBUG_STATE_INACTIVE:
 395                         obj->state = ODEBUG_STATE_ACTIVE;
 396                         break;
 397
 398                 case ODEBUG_STATE_ACTIVE:
 399                         debug_print_object(obj, "activate");
 400                         state = obj->state;
 401                         raw_spin_unlock_irqrestore(&db->lock, flags);
 402                         debug_object_fixup(descr->fixup_activate, addr, state);
 403                         return;
 404
 405                 case ODEBUG_STATE_DESTROYED:
 406                         debug_print_object(obj, "activate");
 407                         break;
 408                 default:
 409                         break;
 410                 }
 411                 raw_spin_unlock_irqrestore(&db->lock, flags);
 412                 return;
 413         }
 414
 415         raw_spin_unlock_irqrestore(&db->lock, flags);
 416         /*
 417          * This happens when a static object is activated. We
 418          * let the type specific code decide whether this is
 419          * true or not.
 420          */
 421         debug_object_fixup(descr->fixup_activate, addr,
 422                            ODEBUG_STATE_NOTAVAILABLE);
 423 }
 424
 425 /**
 426  * debug_object_deactivate - debug checks when an object is deactivated
 427  * @addr:       address of the object
 428  * @descr:      pointer to an object specific debug description structure
 429  */
 430 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 431 {
 432         struct debug_bucket *db;
 433         struct debug_obj *obj;
 434         unsigned long flags;
 435
 436         if (!debug_objects_enabled)
 437                 return;
 438
 439         db = get_bucket((unsigned long) addr);
 440
 441         raw_spin_lock_irqsave(&db->lock, flags);
 442
 443         obj = lookup_object(addr, db);
 444         if (obj) {
 445                 switch (obj->state) {
 446                 case ODEBUG_STATE_INIT:
 447                 case ODEBUG_STATE_INACTIVE:
 448                 case ODEBUG_STATE_ACTIVE:
 449                         obj->state = ODEBUG_STATE_INACTIVE;
 450                         break;
 451
 452                 case ODEBUG_STATE_DESTROYED:
 453                         debug_print_object(obj, "deactivate");
 454                         break;
 455                 default:
 456                         break;
 457                 }
 458         } else {
 459                 struct debug_obj o = { .object = addr,
 460                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 461                                        .descr = descr };
 462
 463                 debug_print_object(&o, "deactivate");
 464         }
 465
 466         raw_spin_unlock_irqrestore(&db->lock, flags);
 467 }
 468
 469 /**
 470  * debug_object_destroy - debug checks when an object is destroyed
 471  * @addr:       address of the object
 472  * @descr:      pointer to an object specific debug description structure
 473  */
 474 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 475 {
 476         enum debug_obj_state state;
 477         struct debug_bucket *db;
 478         struct debug_obj *obj;
 479         unsigned long flags;
 480
 481         if (!debug_objects_enabled)
 482                 return;
 483
 484         db = get_bucket((unsigned long) addr);
 485
 486         raw_spin_lock_irqsave(&db->lock, flags);
 487
 488         obj = lookup_object(addr, db);
 489         if (!obj)
 490                 goto out_unlock;
 491
 492         switch (obj->state) {
 493         case ODEBUG_STATE_NONE:
 494         case ODEBUG_STATE_INIT:
 495         case ODEBUG_STATE_INACTIVE:
 496                 obj->state = ODEBUG_STATE_DESTROYED;
 497                 break;
 498         case ODEBUG_STATE_ACTIVE:
 499                 debug_print_object(obj, "destroy");
 500                 state = obj->state;
 501                 raw_spin_unlock_irqrestore(&db->lock, flags);
 502                 debug_object_fixup(descr->fixup_destroy, addr, state);
 503                 return;
 504
 505         case ODEBUG_STATE_DESTROYED:
 506                 debug_print_object(obj, "destroy");
 507                 break;
 508         default:
 509                 break;
 510         }
 511 out_unlock:
 512         raw_spin_unlock_irqrestore(&db->lock, flags);
 513 }
 514
 515 /**
 516  * debug_object_free - debug checks when an object is freed
 517  * @addr:       address of the object
 518  * @descr:      pointer to an object specific debug description structure
 519  */
 520 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 521 {
 522         enum debug_obj_state state;
 523         struct debug_bucket *db;
 524         struct debug_obj *obj;
 525         unsigned long flags;
 526
 527         if (!debug_objects_enabled)
 528                 return;
 529
 530         db = get_bucket((unsigned long) addr);
 531
 532         raw_spin_lock_irqsave(&db->lock, flags);
 533
 534         obj = lookup_object(addr, db);
 535         if (!obj)
 536                 goto out_unlock;
 537
 538         switch (obj->state) {
 539         case ODEBUG_STATE_ACTIVE:
 540                 debug_print_object(obj, "free");
 541                 state = obj->state;
 542                 raw_spin_unlock_irqrestore(&db->lock, flags);
 543                 debug_object_fixup(descr->fixup_free, addr, state);
 544                 return;
 545         default:
 546                 hlist_del(&obj->node);
 547                 raw_spin_unlock_irqrestore(&db->lock, flags);
 548                 free_object(obj);
 549                 return;
 550         }
 551 out_unlock:
 552         raw_spin_unlock_irqrestore(&db->lock, flags);
 553 }
 554
 555 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 556 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 557 {
 558         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 559         struct hlist_node *node, *tmp;
 560         HLIST_HEAD(freelist);
 561         struct debug_obj_descr *descr;
 562         enum debug_obj_state state;
 563         struct debug_bucket *db;
 564         struct debug_obj *obj;
 565         int cnt;
 566
 567         saddr = (unsigned long) address;
 568         eaddr = saddr + size;
 569         paddr = saddr & ODEBUG_CHUNK_MASK;
 570         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 571         chunks >>= ODEBUG_CHUNK_SHIFT;
 572
 573         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 574                 db = get_bucket(paddr);
 575
 576 repeat:
 577                 cnt = 0;
 578                 raw_spin_lock_irqsave(&db->lock, flags);
 579                 hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
 580                         cnt++;
 581                         oaddr = (unsigned long) obj->object;
 582                         if (oaddr < saddr || oaddr >= eaddr)
 583                                 continue;
 584
 585                         switch (obj->state) {
 586                         case ODEBUG_STATE_ACTIVE:
 587                                 debug_print_object(obj, "free");
 588                                 descr = obj->descr;
 589                                 state = obj->state;
 590                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 591                                 debug_object_fixup(descr->fixup_free,
 592                                                    (void *) oaddr, state);
 593                                 goto repeat;
 594                         default:
 595                                 hlist_del(&obj->node);
 596                                 hlist_add_head(&obj->node, &freelist);
 597                                 break;
 598                         }
 599                 }
 600                 raw_spin_unlock_irqrestore(&db->lock, flags);
 601
 602                 /* Now free them */
 603                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 604                         hlist_del(&obj->node);
 605                         free_object(obj);
 606                 }
 607
 608                 if (cnt > debug_objects_maxchain)
 609                         debug_objects_maxchain = cnt;
 610         }
 611 }
 612
 613 void debug_check_no_obj_freed(const void *address, unsigned long size)
 614 {
 615         if (debug_objects_enabled)
 616                 __debug_check_no_obj_freed(address, size);
 617 }
 618 #endif
 619
 620 #ifdef CONFIG_DEBUG_FS
 621
 622 static int debug_stats_show(struct seq_file *m, void *v)
 623 {
 624         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 625         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 626         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 627         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 628         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 629         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 630         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 631         return 0;
 632 }
 633
 634 static int debug_stats_open(struct inode *inode, struct file *filp)
 635 {
 636         return single_open(filp, debug_stats_show, NULL);
 637 }
 638
 639 static const struct file_operations debug_stats_fops = {
 640         .open           = debug_stats_open,
 641         .read           = seq_read,
 642         .llseek         = seq_lseek,
 643         .release        = single_release,
 644 };
 645
 646 static int __init debug_objects_init_debugfs(void)
 647 {
 648         struct dentry *dbgdir, *dbgstats;
 649
 650         if (!debug_objects_enabled)
 651                 return 0;
 652
 653         dbgdir = debugfs_create_dir("debug_objects", NULL);
 654         if (!dbgdir)
 655                 return -ENOMEM;
 656
 657         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 658                                        &debug_stats_fops);
 659         if (!dbgstats)
 660                 goto err;
 661
 662         return 0;
 663
 664 err:
 665         debugfs_remove(dbgdir);
 666
 667         return -ENOMEM;
 668 }
 669 __initcall(debug_objects_init_debugfs);
 670
 671 #else
 672 static inline void debug_objects_init_debugfs(void) { }
 673 #endif
 674
 675 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 676
 677 /* Random data structure for the self test */
 678 struct self_test {
 679         unsigned long   dummy1[6];
 680         int             static_init;
 681         unsigned long   dummy2[3];
 682 };
 683
 684 static __initdata struct debug_obj_descr descr_type_test;
 685
 686 /*
 687  * fixup_init is called when:
 688  * - an active object is initialized
 689  */
 690 static int __init fixup_init(void *addr, enum debug_obj_state state)
 691 {
 692         struct self_test *obj = addr;
 693
 694         switch (state) {
 695         case ODEBUG_STATE_ACTIVE:
 696                 debug_object_deactivate(obj, &descr_type_test);
 697                 debug_object_init(obj, &descr_type_test);
 698                 return 1;
 699         default:
 700                 return 0;
 701         }
 702 }
 703
 704 /*
 705  * fixup_activate is called when:
 706  * - an active object is activated
 707  * - an unknown object is activated (might be a statically initialized object)
 708  */
 709 static int __init fixup_activate(void *addr, enum debug_obj_state state)
 710 {
 711         struct self_test *obj = addr;
 712
 713         switch (state) {
 714         case ODEBUG_STATE_NOTAVAILABLE:
 715                 if (obj->static_init == 1) {
 716                         debug_object_init(obj, &descr_type_test);
 717                         debug_object_activate(obj, &descr_type_test);
 718                         /*
 719                          * Real code should return 0 here ! This is
 720                          * not a fixup of some bad behaviour. We
 721                          * merily call the debug_init function to keep
 722                          * track of the object.
 723                          */
 724                         return 1;
 725                 } else {
 726                         /* Real code needs to emit a warning here */
 727                 }
 728                 return 0;
 729
 730         case ODEBUG_STATE_ACTIVE:
 731                 debug_object_deactivate(obj, &descr_type_test);
 732                 debug_object_activate(obj, &descr_type_test);
 733                 return 1;
 734
 735         default:
 736                 return 0;
 737         }
 738 }
 739
 740 /*
 741  * fixup_destroy is called when:
 742  * - an active object is destroyed
 743  */
 744 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
 745 {
 746         struct self_test *obj = addr;
 747
 748         switch (state) {
 749         case ODEBUG_STATE_ACTIVE:
 750                 debug_object_deactivate(obj, &descr_type_test);
 751                 debug_object_destroy(obj, &descr_type_test);
 752                 return 1;
 753         default:
 754                 return 0;
 755         }
 756 }
 757
 758 /*
 759  * fixup_free is called when:
 760  * - an active object is freed
 761  */
 762 static int __init fixup_free(void *addr, enum debug_obj_state state)
 763 {
 764         struct self_test *obj = addr;
 765
 766         switch (state) {
 767         case ODEBUG_STATE_ACTIVE:
 768                 debug_object_deactivate(obj, &descr_type_test);
 769                 debug_object_free(obj, &descr_type_test);
 770                 return 1;
 771         default:
 772                 return 0;
 773         }
 774 }
 775
 776 static int
 777 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 778 {
 779         struct debug_bucket *db;
 780         struct debug_obj *obj;
 781         unsigned long flags;
 782         int res = -EINVAL;
 783
 784         db = get_bucket((unsigned long) addr);
 785
 786         raw_spin_lock_irqsave(&db->lock, flags);
 787
 788         obj = lookup_object(addr, db);
 789         if (!obj && state != ODEBUG_STATE_NONE) {
 790                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 791                 goto out;
 792         }
 793         if (obj && obj->state != state) {
 794                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 795                        obj->state, state);
 796                 goto out;
 797         }
 798         if (fixups != debug_objects_fixups) {
 799                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 800                        fixups, debug_objects_fixups);
 801                 goto out;
 802         }
 803         if (warnings != debug_objects_warnings) {
 804                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 805                        warnings, debug_objects_warnings);
 806                 goto out;
 807         }
 808         res = 0;
 809 out:
 810         raw_spin_unlock_irqrestore(&db->lock, flags);
 811         if (res)
 812                 debug_objects_enabled = 0;
 813         return res;
 814 }
 815
 816 static __initdata struct debug_obj_descr descr_type_test = {
 817         .name                   = "selftest",
 818         .fixup_init             = fixup_init,
 819         .fixup_activate         = fixup_activate,
 820         .fixup_destroy          = fixup_destroy,
 821         .fixup_free             = fixup_free,
 822 };
 823
 824 static __initdata struct self_test obj = { .static_init = 0 };
 825
 826 static void __init debug_objects_selftest(void)
 827 {
 828         int fixups, oldfixups, warnings, oldwarnings;
 829         unsigned long flags;
 830
 831         local_irq_save(flags);
 832
 833         fixups = oldfixups = debug_objects_fixups;
 834         warnings = oldwarnings = debug_objects_warnings;
 835         descr_test = &descr_type_test;
 836
 837         debug_object_init(&obj, &descr_type_test);
 838         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 839                 goto out;
 840         debug_object_activate(&obj, &descr_type_test);
 841         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 842                 goto out;
 843         debug_object_activate(&obj, &descr_type_test);
 844         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 845                 goto out;
 846         debug_object_deactivate(&obj, &descr_type_test);
 847         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 848                 goto out;
 849         debug_object_destroy(&obj, &descr_type_test);
 850         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 851                 goto out;
 852         debug_object_init(&obj, &descr_type_test);
 853         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 854                 goto out;
 855         debug_object_activate(&obj, &descr_type_test);
 856         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 857                 goto out;
 858         debug_object_deactivate(&obj, &descr_type_test);
 859         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 860                 goto out;
 861         debug_object_free(&obj, &descr_type_test);
 862         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 863                 goto out;
 864
 865         obj.static_init = 1;
 866         debug_object_activate(&obj, &descr_type_test);
 867         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, warnings))
 868                 goto out;
 869         debug_object_init(&obj, &descr_type_test);
 870         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
 871                 goto out;
 872         debug_object_free(&obj, &descr_type_test);
 873         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 874                 goto out;
 875
 876 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 877         debug_object_init(&obj, &descr_type_test);
 878         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 879                 goto out;
 880         debug_object_activate(&obj, &descr_type_test);
 881         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 882                 goto out;
 883         __debug_check_no_obj_freed(&obj, sizeof(obj));
 884         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
 885                 goto out;
 886 #endif
 887         printk(KERN_INFO "ODEBUG: selftest passed\n");
 888
 889 out:
 890         debug_objects_fixups = oldfixups;
 891         debug_objects_warnings = oldwarnings;
 892         descr_test = NULL;
 893
 894         local_irq_restore(flags);
 895 }
 896 #else
 897 static inline void debug_objects_selftest(void) { }
 898 #endif
 899
 900 /*
 901  * Called during early boot to initialize the hash buckets and link
 902  * the static object pool objects into the poll list. After this call
 903  * the object tracker is fully operational.
 904  */
 905 void __init debug_objects_early_init(void)
 906 {
 907         int i;
 908
 909         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
 910                 raw_spin_lock_init(&obj_hash[i].lock);
 911
 912         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
 913                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
 914 }
 915
 916 /*
 917  * Convert the statically allocated objects to dynamic ones:
 918  */
 919 static int debug_objects_replace_static_objects(void)
 920 {
 921         struct debug_bucket *db = obj_hash;
 922         struct hlist_node *node, *tmp;
 923         struct debug_obj *obj, *new;
 924         HLIST_HEAD(objects);
 925         int i, cnt = 0;
 926
 927         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
 928                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
 929                 if (!obj)
 930                         goto free;
 931                 hlist_add_head(&obj->node, &objects);
 932         }
 933
 934         /*
 935          * When debug_objects_mem_init() is called we know that only
 936          * one CPU is up, so disabling interrupts is enough
 937          * protection. This avoids the lockdep hell of lock ordering.
 938          */
 939         local_irq_disable();
 940
 941         /* Remove the statically allocated objects from the pool */
 942         hlist_for_each_entry_safe(obj, node, tmp, &obj_pool, node)
 943                 hlist_del(&obj->node);
 944         /* Move the allocated objects to the pool */
 945         hlist_move_list(&objects, &obj_pool);
 946
 947         /* Replace the active object references */
 948         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 949                 hlist_move_list(&db->list, &objects);
 950
 951                 hlist_for_each_entry(obj, node, &objects, node) {
 952                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
 953                         hlist_del(&new->node);
 954                         /* copy object data */
 955                         *new = *obj;
 956                         hlist_add_head(&new->node, &db->list);
 957                         cnt++;
 958                 }
 959         }
 960
 961         printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
 962                obj_pool_used);
 963         local_irq_enable();
 964         return 0;
 965 free:
 966         hlist_for_each_entry_safe(obj, node, tmp, &objects, node) {
 967                 hlist_del(&obj->node);
 968                 kmem_cache_free(obj_cache, obj);
 969         }
 970         return -ENOMEM;
 971 }
 972
 973 /*
 974  * Called after the kmem_caches are functional to setup a dedicated
 975  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
 976  * prevents that the debug code is called on kmem_cache_free() for the
 977  * debug tracker objects to avoid recursive calls.
 978  */
 979 void __init debug_objects_mem_init(void)
 980 {
 981         if (!debug_objects_enabled)
 982                 return;
 983
 984         obj_cache = kmem_cache_create("debug_objects_cache",
 985                                       sizeof (struct debug_obj), 0,
 986                                       SLAB_DEBUG_OBJECTS, NULL);
 987
 988         if (!obj_cache || debug_objects_replace_static_objects()) {
 989                 debug_objects_enabled = 0;
 990                 if (obj_cache)
 991                         kmem_cache_destroy(obj_cache);
 992                 printk(KERN_WARNING "ODEBUG: out of memory.\n");
 993         } else
 994                 debug_objects_selftest();
 995 }