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/slab.h>
  16 #include <linux/hash.h>
  17
  18 #define ODEBUG_HASH_BITS        14
  19 #define ODEBUG_HASH_SIZE        (1 << ODEBUG_HASH_BITS)
  20
  21 #define ODEBUG_POOL_SIZE        512
  22 #define ODEBUG_POOL_MIN_LEVEL   256
  23
  24 #define ODEBUG_CHUNK_SHIFT      PAGE_SHIFT
  25 #define ODEBUG_CHUNK_SIZE       (1 << ODEBUG_CHUNK_SHIFT)
  26 #define ODEBUG_CHUNK_MASK       (~(ODEBUG_CHUNK_SIZE - 1))
  27
  28 struct debug_bucket {
  29         struct hlist_head       list;
  30         raw_spinlock_t          lock;
  31 };
  32
  33 static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  34
  35 static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  36
  37 static DEFINE_RAW_SPINLOCK(pool_lock);
  38
  39 static HLIST_HEAD(obj_pool);
  40
  41 static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  42 static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  43 static int                      obj_pool_used;
  44 static int                      obj_pool_max_used;
  45 static struct kmem_cache        *obj_cache;
  46
  47 static int                      debug_objects_maxchain __read_mostly;
  48 static int                      debug_objects_fixups __read_mostly;
  49 static int                      debug_objects_warnings __read_mostly;
  50 static int                      debug_objects_enabled __read_mostly
  51                                 = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  52
  53 static struct debug_obj_descr   *descr_test  __read_mostly;
  54
  55 static void free_obj_work(struct work_struct *work);
  56 static DECLARE_WORK(debug_obj_work, free_obj_work);
  57
  58 static int __init enable_object_debug(char *str)
  59 {
  60         debug_objects_enabled = 1;
  61         return 0;
  62 }
  63
  64 static int __init disable_object_debug(char *str)
  65 {
  66         debug_objects_enabled = 0;
  67         return 0;
  68 }
  69
  70 early_param("debug_objects", enable_object_debug);
  71 early_param("no_debug_objects", disable_object_debug);
  72
  73 static const char *obj_states[ODEBUG_STATE_MAX] = {
  74         [ODEBUG_STATE_NONE]             = "none",
  75         [ODEBUG_STATE_INIT]             = "initialized",
  76         [ODEBUG_STATE_INACTIVE]         = "inactive",
  77         [ODEBUG_STATE_ACTIVE]           = "active",
  78         [ODEBUG_STATE_DESTROYED]        = "destroyed",
  79         [ODEBUG_STATE_NOTAVAILABLE]     = "not available",
  80 };
  81
  82 static int fill_pool(void)
  83 {
  84         gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
  85         struct debug_obj *new;
  86         unsigned long flags;
  87
  88         if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
  89                 return obj_pool_free;
  90
  91         if (unlikely(!obj_cache))
  92                 return obj_pool_free;
  93
  94         while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
  95
  96                 new = kmem_cache_zalloc(obj_cache, gfp);
  97                 if (!new)
  98                         return obj_pool_free;
  99
 100                 raw_spin_lock_irqsave(&pool_lock, flags);
 101                 hlist_add_head(&new->node, &obj_pool);
 102                 obj_pool_free++;
 103                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 104         }
 105         return obj_pool_free;
 106 }
 107
 108 /*
 109  * Lookup an object in the hash bucket.
 110  */
 111 static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
 112 {
 113         struct hlist_node *node;
 114         struct debug_obj *obj;
 115         int cnt = 0;
 116
 117         hlist_for_each_entry(obj, node, &b->list, node) {
 118                 cnt++;
 119                 if (obj->object == addr)
 120                         return obj;
 121         }
 122         if (cnt > debug_objects_maxchain)
 123                 debug_objects_maxchain = cnt;
 124
 125         return NULL;
 126 }
 127
 128 /*
 129  * Allocate a new object. If the pool is empty, switch off the debugger.
 130  * Must be called with interrupts disabled.
 131  */
 132 static struct debug_obj *
 133 alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
 134 {
 135         struct debug_obj *obj = NULL;
 136
 137         raw_spin_lock(&pool_lock);
 138         if (obj_pool.first) {
 139                 obj         = hlist_entry(obj_pool.first, typeof(*obj), node);
 140
 141                 obj->object = addr;
 142                 obj->descr  = descr;
 143                 obj->state  = ODEBUG_STATE_NONE;
 144                 obj->astate = 0;
 145                 hlist_del(&obj->node);
 146
 147                 hlist_add_head(&obj->node, &b->list);
 148
 149                 obj_pool_used++;
 150                 if (obj_pool_used > obj_pool_max_used)
 151                         obj_pool_max_used = obj_pool_used;
 152
 153                 obj_pool_free--;
 154                 if (obj_pool_free < obj_pool_min_free)
 155                         obj_pool_min_free = obj_pool_free;
 156         }
 157         raw_spin_unlock(&pool_lock);
 158
 159         return obj;
 160 }
 161
 162 /*
 163  * workqueue function to free objects.
 164  */
 165 static void free_obj_work(struct work_struct *work)
 166 {
 167         struct debug_obj *obj;
 168         unsigned long flags;
 169
 170         raw_spin_lock_irqsave(&pool_lock, flags);
 171         while (obj_pool_free > ODEBUG_POOL_SIZE) {
 172                 obj = hlist_entry(obj_pool.first, typeof(*obj), node);
 173                 hlist_del(&obj->node);
 174                 obj_pool_free--;
 175                 /*
 176                  * We release pool_lock across kmem_cache_free() to
 177                  * avoid contention on pool_lock.
 178                  */
 179                 raw_spin_unlock_irqrestore(&pool_lock, flags);
 180                 kmem_cache_free(obj_cache, obj);
 181                 raw_spin_lock_irqsave(&pool_lock, flags);
 182         }
 183         raw_spin_unlock_irqrestore(&pool_lock, flags);
 184 }
 185
 186 /*
 187  * Put the object back into the pool and schedule work to free objects
 188  * if necessary.
 189  */
 190 static void free_object(struct debug_obj *obj)
 191 {
 192         unsigned long flags;
 193         int sched = 0;
 194
 195         raw_spin_lock_irqsave(&pool_lock, flags);
 196         /*
 197          * schedule work when the pool is filled and the cache is
 198          * initialized:
 199          */
 200         if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
 201                 sched = keventd_up() && !work_pending(&debug_obj_work);
 202         hlist_add_head(&obj->node, &obj_pool);
 203         obj_pool_free++;
 204         obj_pool_used--;
 205         raw_spin_unlock_irqrestore(&pool_lock, flags);
 206         if (sched)
 207                 schedule_work(&debug_obj_work);
 208 }
 209
 210 /*
 211  * We run out of memory. That means we probably have tons of objects
 212  * allocated.
 213  */
 214 static void debug_objects_oom(void)
 215 {
 216         struct debug_bucket *db = obj_hash;
 217         struct hlist_node *node, *tmp;
 218         HLIST_HEAD(freelist);
 219         struct debug_obj *obj;
 220         unsigned long flags;
 221         int i;
 222
 223         printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");
 224
 225         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
 226                 raw_spin_lock_irqsave(&db->lock, flags);
 227                 hlist_move_list(&db->list, &freelist);
 228                 raw_spin_unlock_irqrestore(&db->lock, flags);
 229
 230                 /* Now free them */
 231                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 232                         hlist_del(&obj->node);
 233                         free_object(obj);
 234                 }
 235         }
 236 }
 237
 238 /*
 239  * We use the pfn of the address for the hash. That way we can check
 240  * for freed objects simply by checking the affected bucket.
 241  */
 242 static struct debug_bucket *get_bucket(unsigned long addr)
 243 {
 244         unsigned long hash;
 245
 246         hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
 247         return &obj_hash[hash];
 248 }
 249
 250 static void debug_print_object(struct debug_obj *obj, char *msg)
 251 {
 252         struct debug_obj_descr *descr = obj->descr;
 253         static int limit;
 254
 255         if (limit < 5 && descr != descr_test) {
 256                 void *hint = descr->debug_hint ?
 257                         descr->debug_hint(obj->object) : NULL;
 258                 limit++;
 259                 WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
 260                                  "object type: %s hint: %pS\n",
 261                         msg, obj_states[obj->state], obj->astate,
 262                         descr->name, hint);
 263         }
 264         debug_objects_warnings++;
 265 }
 266
 267 /*
 268  * Try to repair the damage, so we have a better chance to get useful
 269  * debug output.
 270  */
 271 static int
 272 debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
 273                    void * addr, enum debug_obj_state state)
 274 {
 275         int fixed = 0;
 276
 277         if (fixup)
 278                 fixed = fixup(addr, state);
 279         debug_objects_fixups += fixed;
 280         return fixed;
 281 }
 282
 283 static void debug_object_is_on_stack(void *addr, int onstack)
 284 {
 285         int is_on_stack;
 286         static int limit;
 287
 288         if (limit > 4)
 289                 return;
 290
 291         is_on_stack = object_is_on_stack(addr);
 292         if (is_on_stack == onstack)
 293                 return;
 294
 295         limit++;
 296         if (is_on_stack)
 297                 printk(KERN_WARNING
 298                        "ODEBUG: object is on stack, but not annotated\n");
 299         else
 300                 printk(KERN_WARNING
 301                        "ODEBUG: object is not on stack, but annotated\n");
 302         WARN_ON(1);
 303 }
 304
 305 static void
 306 __debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
 307 {
 308         enum debug_obj_state state;
 309         struct debug_bucket *db;
 310         struct debug_obj *obj;
 311         unsigned long flags;
 312
 313         fill_pool();
 314
 315         db = get_bucket((unsigned long) addr);
 316
 317         raw_spin_lock_irqsave(&db->lock, flags);
 318
 319         obj = lookup_object(addr, db);
 320         if (!obj) {
 321                 obj = alloc_object(addr, db, descr);
 322                 if (!obj) {
 323                         debug_objects_enabled = 0;
 324                         raw_spin_unlock_irqrestore(&db->lock, flags);
 325                         debug_objects_oom();
 326                         return;
 327                 }
 328                 debug_object_is_on_stack(addr, onstack);
 329         }
 330
 331         switch (obj->state) {
 332         case ODEBUG_STATE_NONE:
 333         case ODEBUG_STATE_INIT:
 334         case ODEBUG_STATE_INACTIVE:
 335                 obj->state = ODEBUG_STATE_INIT;
 336                 break;
 337
 338         case ODEBUG_STATE_ACTIVE:
 339                 debug_print_object(obj, "init");
 340                 state = obj->state;
 341                 raw_spin_unlock_irqrestore(&db->lock, flags);
 342                 debug_object_fixup(descr->fixup_init, addr, state);
 343                 return;
 344
 345         case ODEBUG_STATE_DESTROYED:
 346                 debug_print_object(obj, "init");
 347                 break;
 348         default:
 349                 break;
 350         }
 351
 352         raw_spin_unlock_irqrestore(&db->lock, flags);
 353 }
 354
 355 /**
 356  * debug_object_init - debug checks when an object is initialized
 357  * @addr:       address of the object
 358  * @descr:      pointer to an object specific debug description structure
 359  */
 360 void debug_object_init(void *addr, struct debug_obj_descr *descr)
 361 {
 362         if (!debug_objects_enabled)
 363                 return;
 364
 365         __debug_object_init(addr, descr, 0);
 366 }
 367
 368 /**
 369  * debug_object_init_on_stack - debug checks when an object on stack is
 370  *                              initialized
 371  * @addr:       address of the object
 372  * @descr:      pointer to an object specific debug description structure
 373  */
 374 void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
 375 {
 376         if (!debug_objects_enabled)
 377                 return;
 378
 379         __debug_object_init(addr, descr, 1);
 380 }
 381
 382 /**
 383  * debug_object_activate - debug checks when an object is activated
 384  * @addr:       address of the object
 385  * @descr:      pointer to an object specific debug description structure
 386  */
 387 void debug_object_activate(void *addr, struct debug_obj_descr *descr)
 388 {
 389         enum debug_obj_state state;
 390         struct debug_bucket *db;
 391         struct debug_obj *obj;
 392         unsigned long flags;
 393         struct debug_obj o = { .object = addr,
 394                                .state = ODEBUG_STATE_NOTAVAILABLE,
 395                                .descr = descr };
 396
 397         if (!debug_objects_enabled)
 398                 return;
 399
 400         db = get_bucket((unsigned long) addr);
 401
 402         raw_spin_lock_irqsave(&db->lock, flags);
 403
 404         obj = lookup_object(addr, db);
 405         if (obj) {
 406                 switch (obj->state) {
 407                 case ODEBUG_STATE_INIT:
 408                 case ODEBUG_STATE_INACTIVE:
 409                         obj->state = ODEBUG_STATE_ACTIVE;
 410                         break;
 411
 412                 case ODEBUG_STATE_ACTIVE:
 413                         debug_print_object(obj, "activate");
 414                         state = obj->state;
 415                         raw_spin_unlock_irqrestore(&db->lock, flags);
 416                         debug_object_fixup(descr->fixup_activate, addr, state);
 417                         return;
 418
 419                 case ODEBUG_STATE_DESTROYED:
 420                         debug_print_object(obj, "activate");
 421                         break;
 422                 default:
 423                         break;
 424                 }
 425                 raw_spin_unlock_irqrestore(&db->lock, flags);
 426                 return;
 427         }
 428
 429         raw_spin_unlock_irqrestore(&db->lock, flags);
 430         /*
 431          * This happens when a static object is activated. We
 432          * let the type specific code decide whether this is
 433          * true or not.
 434          */
 435         if (debug_object_fixup(descr->fixup_activate, addr,
 436                            ODEBUG_STATE_NOTAVAILABLE))
 437                 debug_print_object(&o, "activate");
 438 }
 439
 440 /**
 441  * debug_object_deactivate - debug checks when an object is deactivated
 442  * @addr:       address of the object
 443  * @descr:      pointer to an object specific debug description structure
 444  */
 445 void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
 446 {
 447         struct debug_bucket *db;
 448         struct debug_obj *obj;
 449         unsigned long flags;
 450
 451         if (!debug_objects_enabled)
 452                 return;
 453
 454         db = get_bucket((unsigned long) addr);
 455
 456         raw_spin_lock_irqsave(&db->lock, flags);
 457
 458         obj = lookup_object(addr, db);
 459         if (obj) {
 460                 switch (obj->state) {
 461                 case ODEBUG_STATE_INIT:
 462                 case ODEBUG_STATE_INACTIVE:
 463                 case ODEBUG_STATE_ACTIVE:
 464                         if (!obj->astate)
 465                                 obj->state = ODEBUG_STATE_INACTIVE;
 466                         else
 467                                 debug_print_object(obj, "deactivate");
 468                         break;
 469
 470                 case ODEBUG_STATE_DESTROYED:
 471                         debug_print_object(obj, "deactivate");
 472                         break;
 473                 default:
 474                         break;
 475                 }
 476         } else {
 477                 struct debug_obj o = { .object = addr,
 478                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 479                                        .descr = descr };
 480
 481                 debug_print_object(&o, "deactivate");
 482         }
 483
 484         raw_spin_unlock_irqrestore(&db->lock, flags);
 485 }
 486
 487 /**
 488  * debug_object_destroy - debug checks when an object is destroyed
 489  * @addr:       address of the object
 490  * @descr:      pointer to an object specific debug description structure
 491  */
 492 void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
 493 {
 494         enum debug_obj_state state;
 495         struct debug_bucket *db;
 496         struct debug_obj *obj;
 497         unsigned long flags;
 498
 499         if (!debug_objects_enabled)
 500                 return;
 501
 502         db = get_bucket((unsigned long) addr);
 503
 504         raw_spin_lock_irqsave(&db->lock, flags);
 505
 506         obj = lookup_object(addr, db);
 507         if (!obj)
 508                 goto out_unlock;
 509
 510         switch (obj->state) {
 511         case ODEBUG_STATE_NONE:
 512         case ODEBUG_STATE_INIT:
 513         case ODEBUG_STATE_INACTIVE:
 514                 obj->state = ODEBUG_STATE_DESTROYED;
 515                 break;
 516         case ODEBUG_STATE_ACTIVE:
 517                 debug_print_object(obj, "destroy");
 518                 state = obj->state;
 519                 raw_spin_unlock_irqrestore(&db->lock, flags);
 520                 debug_object_fixup(descr->fixup_destroy, addr, state);
 521                 return;
 522
 523         case ODEBUG_STATE_DESTROYED:
 524                 debug_print_object(obj, "destroy");
 525                 break;
 526         default:
 527                 break;
 528         }
 529 out_unlock:
 530         raw_spin_unlock_irqrestore(&db->lock, flags);
 531 }
 532
 533 /**
 534  * debug_object_free - debug checks when an object is freed
 535  * @addr:       address of the object
 536  * @descr:      pointer to an object specific debug description structure
 537  */
 538 void debug_object_free(void *addr, struct debug_obj_descr *descr)
 539 {
 540         enum debug_obj_state state;
 541         struct debug_bucket *db;
 542         struct debug_obj *obj;
 543         unsigned long flags;
 544
 545         if (!debug_objects_enabled)
 546                 return;
 547
 548         db = get_bucket((unsigned long) addr);
 549
 550         raw_spin_lock_irqsave(&db->lock, flags);
 551
 552         obj = lookup_object(addr, db);
 553         if (!obj)
 554                 goto out_unlock;
 555
 556         switch (obj->state) {
 557         case ODEBUG_STATE_ACTIVE:
 558                 debug_print_object(obj, "free");
 559                 state = obj->state;
 560                 raw_spin_unlock_irqrestore(&db->lock, flags);
 561                 debug_object_fixup(descr->fixup_free, addr, state);
 562                 return;
 563         default:
 564                 hlist_del(&obj->node);
 565                 raw_spin_unlock_irqrestore(&db->lock, flags);
 566                 free_object(obj);
 567                 return;
 568         }
 569 out_unlock:
 570         raw_spin_unlock_irqrestore(&db->lock, flags);
 571 }
 572
 573 /**
 574  * debug_object_assert_init - debug checks when object should be init-ed
 575  * @addr:       address of the object
 576  * @descr:      pointer to an object specific debug description structure
 577  */
 578 void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
 579 {
 580         struct debug_bucket *db;
 581         struct debug_obj *obj;
 582         unsigned long flags;
 583
 584         if (!debug_objects_enabled)
 585                 return;
 586
 587         db = get_bucket((unsigned long) addr);
 588
 589         raw_spin_lock_irqsave(&db->lock, flags);
 590
 591         obj = lookup_object(addr, db);
 592         if (!obj) {
 593                 struct debug_obj o = { .object = addr,
 594                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 595                                        .descr = descr };
 596
 597                 raw_spin_unlock_irqrestore(&db->lock, flags);
 598                 /*
 599                  * Maybe the object is static.  Let the type specific
 600                  * code decide what to do.
 601                  */
 602                 if (debug_object_fixup(descr->fixup_assert_init, addr,
 603                                        ODEBUG_STATE_NOTAVAILABLE))
 604                         debug_print_object(&o, "assert_init");
 605                 return;
 606         }
 607
 608         raw_spin_unlock_irqrestore(&db->lock, flags);
 609 }
 610
 611 /**
 612  * debug_object_active_state - debug checks object usage state machine
 613  * @addr:       address of the object
 614  * @descr:      pointer to an object specific debug description structure
 615  * @expect:     expected state
 616  * @next:       state to move to if expected state is found
 617  */
 618 void
 619 debug_object_active_state(void *addr, struct debug_obj_descr *descr,
 620                           unsigned int expect, unsigned int next)
 621 {
 622         struct debug_bucket *db;
 623         struct debug_obj *obj;
 624         unsigned long flags;
 625
 626         if (!debug_objects_enabled)
 627                 return;
 628
 629         db = get_bucket((unsigned long) addr);
 630
 631         raw_spin_lock_irqsave(&db->lock, flags);
 632
 633         obj = lookup_object(addr, db);
 634         if (obj) {
 635                 switch (obj->state) {
 636                 case ODEBUG_STATE_ACTIVE:
 637                         if (obj->astate == expect)
 638                                 obj->astate = next;
 639                         else
 640                                 debug_print_object(obj, "active_state");
 641                         break;
 642
 643                 default:
 644                         debug_print_object(obj, "active_state");
 645                         break;
 646                 }
 647         } else {
 648                 struct debug_obj o = { .object = addr,
 649                                        .state = ODEBUG_STATE_NOTAVAILABLE,
 650                                        .descr = descr };
 651
 652                 debug_print_object(&o, "active_state");
 653         }
 654
 655         raw_spin_unlock_irqrestore(&db->lock, flags);
 656 }
 657
 658 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 659 static void __debug_check_no_obj_freed(const void *address, unsigned long size)
 660 {
 661         unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
 662         struct hlist_node *node, *tmp;
 663         HLIST_HEAD(freelist);
 664         struct debug_obj_descr *descr;
 665         enum debug_obj_state state;
 666         struct debug_bucket *db;
 667         struct debug_obj *obj;
 668         int cnt;
 669
 670         saddr = (unsigned long) address;
 671         eaddr = saddr + size;
 672         paddr = saddr & ODEBUG_CHUNK_MASK;
 673         chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
 674         chunks >>= ODEBUG_CHUNK_SHIFT;
 675
 676         for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
 677                 db = get_bucket(paddr);
 678
 679 repeat:
 680                 cnt = 0;
 681                 raw_spin_lock_irqsave(&db->lock, flags);
 682                 hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
 683                         cnt++;
 684                         oaddr = (unsigned long) obj->object;
 685                         if (oaddr < saddr || oaddr >= eaddr)
 686                                 continue;
 687
 688                         switch (obj->state) {
 689                         case ODEBUG_STATE_ACTIVE:
 690                                 debug_print_object(obj, "free");
 691                                 descr = obj->descr;
 692                                 state = obj->state;
 693                                 raw_spin_unlock_irqrestore(&db->lock, flags);
 694                                 debug_object_fixup(descr->fixup_free,
 695                                                    (void *) oaddr, state);
 696                                 goto repeat;
 697                         default:
 698                                 hlist_del(&obj->node);
 699                                 hlist_add_head(&obj->node, &freelist);
 700                                 break;
 701                         }
 702                 }
 703                 raw_spin_unlock_irqrestore(&db->lock, flags);
 704
 705                 /* Now free them */
 706                 hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
 707                         hlist_del(&obj->node);
 708                         free_object(obj);
 709                 }
 710
 711                 if (cnt > debug_objects_maxchain)
 712                         debug_objects_maxchain = cnt;
 713         }
 714 }
 715
 716 void debug_check_no_obj_freed(const void *address, unsigned long size)
 717 {
 718         if (debug_objects_enabled)
 719                 __debug_check_no_obj_freed(address, size);
 720 }
 721 #endif
 722
 723 #ifdef CONFIG_DEBUG_FS
 724
 725 static int debug_stats_show(struct seq_file *m, void *v)
 726 {
 727         seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
 728         seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
 729         seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
 730         seq_printf(m, "pool_free     :%d\n", obj_pool_free);
 731         seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
 732         seq_printf(m, "pool_used     :%d\n", obj_pool_used);
 733         seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
 734         return 0;
 735 }
 736
 737 static int debug_stats_open(struct inode *inode, struct file *filp)
 738 {
 739         return single_open(filp, debug_stats_show, NULL);
 740 }
 741
 742 static const struct file_operations debug_stats_fops = {
 743         .open           = debug_stats_open,
 744         .read           = seq_read,
 745         .llseek         = seq_lseek,
 746         .release        = single_release,
 747 };
 748
 749 static int __init debug_objects_init_debugfs(void)
 750 {
 751         struct dentry *dbgdir, *dbgstats;
 752
 753         if (!debug_objects_enabled)
 754                 return 0;
 755
 756         dbgdir = debugfs_create_dir("debug_objects", NULL);
 757         if (!dbgdir)
 758                 return -ENOMEM;
 759
 760         dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
 761                                        &debug_stats_fops);
 762         if (!dbgstats)
 763                 goto err;
 764
 765         return 0;
 766
 767 err:
 768         debugfs_remove(dbgdir);
 769
 770         return -ENOMEM;
 771 }
 772 __initcall(debug_objects_init_debugfs);
 773
 774 #else
 775 static inline void debug_objects_init_debugfs(void) { }
 776 #endif
 777
 778 #ifdef CONFIG_DEBUG_OBJECTS_SELFTEST
 779
 780 /* Random data structure for the self test */
 781 struct self_test {
 782         unsigned long   dummy1[6];
 783         int             static_init;
 784         unsigned long   dummy2[3];
 785 };
 786
 787 static __initdata struct debug_obj_descr descr_type_test;
 788
 789 /*
 790  * fixup_init is called when:
 791  * - an active object is initialized
 792  */
 793 static int __init fixup_init(void *addr, enum debug_obj_state state)
 794 {
 795         struct self_test *obj = addr;
 796
 797         switch (state) {
 798         case ODEBUG_STATE_ACTIVE:
 799                 debug_object_deactivate(obj, &descr_type_test);
 800                 debug_object_init(obj, &descr_type_test);
 801                 return 1;
 802         default:
 803                 return 0;
 804         }
 805 }
 806
 807 /*
 808  * fixup_activate is called when:
 809  * - an active object is activated
 810  * - an unknown object is activated (might be a statically initialized object)
 811  */
 812 static int __init fixup_activate(void *addr, enum debug_obj_state state)
 813 {
 814         struct self_test *obj = addr;
 815
 816         switch (state) {
 817         case ODEBUG_STATE_NOTAVAILABLE:
 818                 if (obj->static_init == 1) {
 819                         debug_object_init(obj, &descr_type_test);
 820                         debug_object_activate(obj, &descr_type_test);
 821                         return 0;
 822                 }
 823                 return 1;
 824
 825         case ODEBUG_STATE_ACTIVE:
 826                 debug_object_deactivate(obj, &descr_type_test);
 827                 debug_object_activate(obj, &descr_type_test);
 828                 return 1;
 829
 830         default:
 831                 return 0;
 832         }
 833 }
 834
 835 /*
 836  * fixup_destroy is called when:
 837  * - an active object is destroyed
 838  */
 839 static int __init fixup_destroy(void *addr, enum debug_obj_state state)
 840 {
 841         struct self_test *obj = addr;
 842
 843         switch (state) {
 844         case ODEBUG_STATE_ACTIVE:
 845                 debug_object_deactivate(obj, &descr_type_test);
 846                 debug_object_destroy(obj, &descr_type_test);
 847                 return 1;
 848         default:
 849                 return 0;
 850         }
 851 }
 852
 853 /*
 854  * fixup_free is called when:
 855  * - an active object is freed
 856  */
 857 static int __init fixup_free(void *addr, enum debug_obj_state state)
 858 {
 859         struct self_test *obj = addr;
 860
 861         switch (state) {
 862         case ODEBUG_STATE_ACTIVE:
 863                 debug_object_deactivate(obj, &descr_type_test);
 864                 debug_object_free(obj, &descr_type_test);
 865                 return 1;
 866         default:
 867                 return 0;
 868         }
 869 }
 870
 871 static int __init
 872 check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
 873 {
 874         struct debug_bucket *db;
 875         struct debug_obj *obj;
 876         unsigned long flags;
 877         int res = -EINVAL;
 878
 879         db = get_bucket((unsigned long) addr);
 880
 881         raw_spin_lock_irqsave(&db->lock, flags);
 882
 883         obj = lookup_object(addr, db);
 884         if (!obj && state != ODEBUG_STATE_NONE) {
 885                 WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
 886                 goto out;
 887         }
 888         if (obj && obj->state != state) {
 889                 WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
 890                        obj->state, state);
 891                 goto out;
 892         }
 893         if (fixups != debug_objects_fixups) {
 894                 WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
 895                        fixups, debug_objects_fixups);
 896                 goto out;
 897         }
 898         if (warnings != debug_objects_warnings) {
 899                 WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
 900                        warnings, debug_objects_warnings);
 901                 goto out;
 902         }
 903         res = 0;
 904 out:
 905         raw_spin_unlock_irqrestore(&db->lock, flags);
 906         if (res)
 907                 debug_objects_enabled = 0;
 908         return res;
 909 }
 910
 911 static __initdata struct debug_obj_descr descr_type_test = {
 912         .name                   = "selftest",
 913         .fixup_init             = fixup_init,
 914         .fixup_activate         = fixup_activate,
 915         .fixup_destroy          = fixup_destroy,
 916         .fixup_free             = fixup_free,
 917 };
 918
 919 static __initdata struct self_test obj = { .static_init = 0 };
 920
 921 static void __init debug_objects_selftest(void)
 922 {
 923         int fixups, oldfixups, warnings, oldwarnings;
 924         unsigned long flags;
 925
 926         local_irq_save(flags);
 927
 928         fixups = oldfixups = debug_objects_fixups;
 929         warnings = oldwarnings = debug_objects_warnings;
 930         descr_test = &descr_type_test;
 931
 932         debug_object_init(&obj, &descr_type_test);
 933         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 934                 goto out;
 935         debug_object_activate(&obj, &descr_type_test);
 936         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 937                 goto out;
 938         debug_object_activate(&obj, &descr_type_test);
 939         if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
 940                 goto out;
 941         debug_object_deactivate(&obj, &descr_type_test);
 942         if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
 943                 goto out;
 944         debug_object_destroy(&obj, &descr_type_test);
 945         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
 946                 goto out;
 947         debug_object_init(&obj, &descr_type_test);
 948         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 949                 goto out;
 950         debug_object_activate(&obj, &descr_type_test);
 951         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 952                 goto out;
 953         debug_object_deactivate(&obj, &descr_type_test);
 954         if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
 955                 goto out;
 956         debug_object_free(&obj, &descr_type_test);
 957         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 958                 goto out;
 959
 960         obj.static_init = 1;
 961         debug_object_activate(&obj, &descr_type_test);
 962         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 963                 goto out;
 964         debug_object_init(&obj, &descr_type_test);
 965         if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
 966                 goto out;
 967         debug_object_free(&obj, &descr_type_test);
 968         if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
 969                 goto out;
 970
 971 #ifdef CONFIG_DEBUG_OBJECTS_FREE
 972         debug_object_init(&obj, &descr_type_test);
 973         if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
 974                 goto out;
 975         debug_object_activate(&obj, &descr_type_test);
 976         if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
 977                 goto out;
 978         __debug_check_no_obj_freed(&obj, sizeof(obj));
 979         if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
 980                 goto out;
 981 #endif
 982         printk(KERN_INFO "ODEBUG: selftest passed\n");
 983
 984 out:
 985         debug_objects_fixups = oldfixups;
 986         debug_objects_warnings = oldwarnings;
 987         descr_test = NULL;
 988
 989         local_irq_restore(flags);
 990 }
 991 #else
 992 static inline void debug_objects_selftest(void) { }
 993 #endif
 994
 995 /*
 996  * Called during early boot to initialize the hash buckets and link
 997  * the static object pool objects into the poll list. After this call
 998  * the object tracker is fully operational.
 999  */
1000 void __init debug_objects_early_init(void)
1001 {
1002         int i;
1003
1004         for (i = 0; i < ODEBUG_HASH_SIZE; i++)
1005                 raw_spin_lock_init(&obj_hash[i].lock);
1006
1007         for (i = 0; i < ODEBUG_POOL_SIZE; i++)
1008                 hlist_add_head(&obj_static_pool[i].node, &obj_pool);
1009 }
1010
1011 /*
1012  * Convert the statically allocated objects to dynamic ones:
1013  */
1014 static int __init debug_objects_replace_static_objects(void)
1015 {
1016         struct debug_bucket *db = obj_hash;
1017         struct hlist_node *node, *tmp;
1018         struct debug_obj *obj, *new;
1019         HLIST_HEAD(objects);
1020         int i, cnt = 0;
1021
1022         for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
1023                 obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
1024                 if (!obj)
1025                         goto free;
1026                 hlist_add_head(&obj->node, &objects);
1027         }
1028
1029         /*
1030          * When debug_objects_mem_init() is called we know that only
1031          * one CPU is up, so disabling interrupts is enough
1032          * protection. This avoids the lockdep hell of lock ordering.
1033          */
1034         local_irq_disable();
1035
1036         /* Remove the statically allocated objects from the pool */
1037         hlist_for_each_entry_safe(obj, node, tmp, &obj_pool, node)
1038                 hlist_del(&obj->node);
1039         /* Move the allocated objects to the pool */
1040         hlist_move_list(&objects, &obj_pool);
1041
1042         /* Replace the active object references */
1043         for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
1044                 hlist_move_list(&db->list, &objects);
1045
1046                 hlist_for_each_entry(obj, node, &objects, node) {
1047                         new = hlist_entry(obj_pool.first, typeof(*obj), node);
1048                         hlist_del(&new->node);
1049                         /* copy object data */
1050                         *new = *obj;
1051                         hlist_add_head(&new->node, &db->list);
1052                         cnt++;
1053                 }
1054         }
1055
1056         printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
1057                obj_pool_used);
1058         local_irq_enable();
1059         return 0;
1060 free:
1061         hlist_for_each_entry_safe(obj, node, tmp, &objects, node) {
1062                 hlist_del(&obj->node);
1063                 kmem_cache_free(obj_cache, obj);
1064         }
1065         return -ENOMEM;
1066 }
1067
1068 /*
1069  * Called after the kmem_caches are functional to setup a dedicated
1070  * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
1071  * prevents that the debug code is called on kmem_cache_free() for the
1072  * debug tracker objects to avoid recursive calls.
1073  */
1074 void __init debug_objects_mem_init(void)
1075 {
1076         if (!debug_objects_enabled)
1077                 return;
1078
1079         obj_cache = kmem_cache_create("debug_objects_cache",
1080                                       sizeof (struct debug_obj), 0,
1081                                       SLAB_DEBUG_OBJECTS, NULL);
1082
1083         if (!obj_cache || debug_objects_replace_static_objects()) {
1084                 debug_objects_enabled = 0;
1085                 if (obj_cache)
1086                         kmem_cache_destroy(obj_cache);
1087                 printk(KERN_WARNING "ODEBUG: out of memory.\n");
1088         } else
1089                 debug_objects_selftest();
1090 }