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