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