linux/lib/debugobjects.c
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   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
  28struct debug_bucket {
  29        struct hlist_head       list;
  30        raw_spinlock_t          lock;
  31};
  32
  33static struct debug_bucket      obj_hash[ODEBUG_HASH_SIZE];
  34
  35static struct debug_obj         obj_static_pool[ODEBUG_POOL_SIZE] __initdata;
  36
  37static DEFINE_RAW_SPINLOCK(pool_lock);
  38
  39static HLIST_HEAD(obj_pool);
  40
  41static int                      obj_pool_min_free = ODEBUG_POOL_SIZE;
  42static int                      obj_pool_free = ODEBUG_POOL_SIZE;
  43static int                      obj_pool_used;
  44static int                      obj_pool_max_used;
  45static struct kmem_cache        *obj_cache;
  46
  47static int                      debug_objects_maxchain __read_mostly;
  48static int                      debug_objects_fixups __read_mostly;
  49static int                      debug_objects_warnings __read_mostly;
  50static int                      debug_objects_enabled __read_mostly
  51                                = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
  52
  53static struct debug_obj_descr   *descr_test  __read_mostly;
  54
  55static void free_obj_work(struct work_struct *work);
  56static DECLARE_WORK(debug_obj_work, free_obj_work);
  57
  58static int __init enable_object_debug(char *str)
  59{
  60        debug_objects_enabled = 1;
  61        return 0;
  62}
  63
  64static int __init disable_object_debug(char *str)
  65{
  66        debug_objects_enabled = 0;
  67        return 0;
  68}
  69
  70early_param("debug_objects", enable_object_debug);
  71early_param("no_debug_objects", disable_object_debug);
  72
  73static 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
  82static 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 */
 111static 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 */
 132static struct debug_obj *
 133alloc_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 */
 165static 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 */
 190static 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 */
 214static 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 */
 242static 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
 250static 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 */
 271static void
 272debug_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
 279static 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
 301static 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 */
 356void 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 */
 370void 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 */
 383void 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 */
 437void 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 */
 484void 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        }
 521out_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 */
 530void 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        }
 561out_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 */
 572void
 573debug_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
 613static 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
 633repeat:
 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
 670void 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
 679static 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
 691static int debug_stats_open(struct inode *inode, struct file *filp)
 692{
 693        return single_open(filp, debug_stats_show, NULL);
 694}
 695
 696static 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
 703static 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
 721err:
 722        debugfs_remove(dbgdir);
 723
 724        return -ENOMEM;
 725}
 726__initcall(debug_objects_init_debugfs);
 727
 728#else
 729static 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 */
 735struct self_test {
 736        unsigned long   dummy1[6];
 737        int             static_init;
 738        unsigned long   dummy2[3];
 739};
 740
 741static __initdata struct debug_obj_descr descr_type_test;
 742
 743/*
 744 * fixup_init is called when:
 745 * - an active object is initialized
 746 */
 747static 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 */
 766static 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 */
 801static 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 */
 819static 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
 833static int __init
 834check_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;
 866out:
 867        raw_spin_unlock_irqrestore(&db->lock, flags);
 868        if (res)
 869                debug_objects_enabled = 0;
 870        return res;
 871}
 872
 873static __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
 881static __initdata struct self_test obj = { .static_init = 0 };
 882
 883static 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
 946out:
 947        debug_objects_fixups = oldfixups;
 948        debug_objects_warnings = oldwarnings;
 949        descr_test = NULL;
 950
 951        local_irq_restore(flags);
 952}
 953#else
 954static 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 */
 962void __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 */
 976static 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;
1022free:
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 */
1036void __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}
1053
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