debugobjects.c

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/*
 * Generic infrastructure for lifetime debugging of objects.
 *
 * Started by Thomas Gleixner
 *
 * Copyright (C) 2008, Thomas Gleixner <[email protected]>
 *
 * For licencing details see kernel-base/COPYING
 */
#include <linux/debugobjects.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/hash.h>

#define ODEBUG_HASH_BITS    14
#define ODEBUG_HASH_SIZE    (1 << ODEBUG_HASH_BITS)

#define ODEBUG_POOL_SIZE    512
#define ODEBUG_POOL_MIN_LEVEL   256

#define ODEBUG_CHUNK_SHIFT  PAGE_SHIFT
#define ODEBUG_CHUNK_SIZE   (1 << ODEBUG_CHUNK_SHIFT)
#define ODEBUG_CHUNK_MASK   (~(ODEBUG_CHUNK_SIZE - 1))

struct debug_bucket {
    struct hlist_head   list;
    raw_spinlock_t      lock;
};

static struct debug_bucket  obj_hash[ODEBUG_HASH_SIZE];

static struct debug_obj     obj_static_pool[ODEBUG_POOL_SIZE] __initdata;

static DEFINE_RAW_SPINLOCK(pool_lock);

static HLIST_HEAD(obj_pool);

static int          obj_pool_min_free = ODEBUG_POOL_SIZE;
static int          obj_pool_free = ODEBUG_POOL_SIZE;
static int          obj_pool_used;
static int          obj_pool_max_used;
static struct kmem_cache    *obj_cache;

static int          debug_objects_maxchain __read_mostly;
static int          debug_objects_fixups __read_mostly;
static int          debug_objects_warnings __read_mostly;
static int          debug_objects_enabled __read_mostly
                = CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;

static struct debug_obj_descr   *descr_test  __read_mostly;

static void free_obj_work(struct work_struct *work);
static DECLARE_WORK(debug_obj_work, free_obj_work);

static int __init enable_object_debug(char *str)
{
    debug_objects_enabled = 1;
    return 0;
}

static int __init disable_object_debug(char *str)
{
    debug_objects_enabled = 0;
    return 0;
}

early_param("debug_objects", enable_object_debug);
early_param("no_debug_objects", disable_object_debug);

static const char *obj_states[ODEBUG_STATE_MAX] = {
    [ODEBUG_STATE_NONE]     = "none",
    [ODEBUG_STATE_INIT]     = "initialized",
    [ODEBUG_STATE_INACTIVE]     = "inactive",
    [ODEBUG_STATE_ACTIVE]       = "active",
    [ODEBUG_STATE_DESTROYED]    = "destroyed",
    [ODEBUG_STATE_NOTAVAILABLE] = "not available",
};

static void fill_pool(void)
{
    gfp_t gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
    struct debug_obj *new;
    unsigned long flags;

    if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
        return;

    if (unlikely(!obj_cache))
        return;

    while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {

        new = kmem_cache_zalloc(obj_cache, gfp);
        if (!new)
            return;

        raw_spin_lock_irqsave(&pool_lock, flags);
        hlist_add_head(&new->node, &obj_pool);
        obj_pool_free++;
        raw_spin_unlock_irqrestore(&pool_lock, flags);
    }
}

/*
 * Lookup an object in the hash bucket.
 */
static struct debug_obj *lookup_object(void *addr, struct debug_bucket *b)
{
    struct hlist_node *node;
    struct debug_obj *obj;
    int cnt = 0;

    hlist_for_each_entry(obj, node, &b->list, node) {
        cnt++;
        if (obj->object == addr)
            return obj;
    }
    if (cnt > debug_objects_maxchain)
        debug_objects_maxchain = cnt;

    return NULL;
}

/*
 * Allocate a new object. If the pool is empty, switch off the debugger.
 * Must be called with interrupts disabled.
 */
static struct debug_obj *
alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
{
    struct debug_obj *obj = NULL;

    raw_spin_lock(&pool_lock);
    if (obj_pool.first) {
        obj     = hlist_entry(obj_pool.first, typeof(*obj), node);

        obj->object = addr;
        obj->descr  = descr;
        obj->state  = ODEBUG_STATE_NONE;
        obj->astate = 0;
        hlist_del(&obj->node);

        hlist_add_head(&obj->node, &b->list);

        obj_pool_used++;
        if (obj_pool_used > obj_pool_max_used)
            obj_pool_max_used = obj_pool_used;

        obj_pool_free--;
        if (obj_pool_free < obj_pool_min_free)
            obj_pool_min_free = obj_pool_free;
    }
    raw_spin_unlock(&pool_lock);

    return obj;
}

/*
 * workqueue function to free objects.
 */
static void free_obj_work(struct work_struct *work)
{
    struct debug_obj *obj;
    unsigned long flags;

    raw_spin_lock_irqsave(&pool_lock, flags);
    while (obj_pool_free > ODEBUG_POOL_SIZE) {
        obj = hlist_entry(obj_pool.first, typeof(*obj), node);
        hlist_del(&obj->node);
        obj_pool_free--;
        /*
         * We release pool_lock across kmem_cache_free() to
         * avoid contention on pool_lock.
         */
        raw_spin_unlock_irqrestore(&pool_lock, flags);
        kmem_cache_free(obj_cache, obj);
        raw_spin_lock_irqsave(&pool_lock, flags);
    }
    raw_spin_unlock_irqrestore(&pool_lock, flags);
}

/*
 * Put the object back into the pool and schedule work to free objects
 * if necessary.
 */
static void free_object(struct debug_obj *obj)
{
    unsigned long flags;
    int sched = 0;

    raw_spin_lock_irqsave(&pool_lock, flags);
    /*
     * schedule work when the pool is filled and the cache is
     * initialized:
     */
    if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
        sched = keventd_up() && !work_pending(&debug_obj_work);
    hlist_add_head(&obj->node, &obj_pool);
    obj_pool_free++;
    obj_pool_used--;
    raw_spin_unlock_irqrestore(&pool_lock, flags);
    if (sched)
        schedule_work(&debug_obj_work);
}

/*
 * We run out of memory. That means we probably have tons of objects
 * allocated.
 */
static void debug_objects_oom(void)
{
    struct debug_bucket *db = obj_hash;
    struct hlist_node *node, *tmp;
    HLIST_HEAD(freelist);
    struct debug_obj *obj;
    unsigned long flags;
    int i;

    printk(KERN_WARNING "ODEBUG: Out of memory. ODEBUG disabled\n");

    for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
        raw_spin_lock_irqsave(&db->lock, flags);
        hlist_move_list(&db->list, &freelist);
        raw_spin_unlock_irqrestore(&db->lock, flags);

        /* Now free them */
        hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
            hlist_del(&obj->node);
            free_object(obj);
        }
    }
}

/*
 * We use the pfn of the address for the hash. That way we can check
 * for freed objects simply by checking the affected bucket.
 */
static struct debug_bucket *get_bucket(unsigned long addr)
{
    unsigned long hash;

    hash = hash_long((addr >> ODEBUG_CHUNK_SHIFT), ODEBUG_HASH_BITS);
    return &obj_hash[hash];
}

static void debug_print_object(struct debug_obj *obj, char *msg)
{
    struct debug_obj_descr *descr = obj->descr;
    static int limit;

    if (limit < 5 && descr != descr_test) {
        void *hint = descr->debug_hint ?
            descr->debug_hint(obj->object) : NULL;
        limit++;
        WARN(1, KERN_ERR "ODEBUG: %s %s (active state %u) "
                 "object type: %s hint: %pS\n",
            msg, obj_states[obj->state], obj->astate,
            descr->name, hint);
    }
    debug_objects_warnings++;
}

/*
 * Try to repair the damage, so we have a better chance to get useful
 * debug output.
 */
static int
debug_object_fixup(int (*fixup)(void *addr, enum debug_obj_state state),
           void * addr, enum debug_obj_state state)
{
    int fixed = 0;

    if (fixup)
        fixed = fixup(addr, state);
    debug_objects_fixups += fixed;
    return fixed;
}

static void debug_object_is_on_stack(void *addr, int onstack)
{
    int is_on_stack;
    static int limit;

    if (limit > 4)
        return;

    is_on_stack = object_is_on_stack(addr);
    if (is_on_stack == onstack)
        return;

    limit++;
    if (is_on_stack)
        printk(KERN_WARNING
               "ODEBUG: object is on stack, but not annotated\n");
    else
        printk(KERN_WARNING
               "ODEBUG: object is not on stack, but annotated\n");
    WARN_ON(1);
}

static void
__debug_object_init(void *addr, struct debug_obj_descr *descr, int onstack)
{
    enum debug_obj_state state;
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;

    fill_pool();

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (!obj) {
        obj = alloc_object(addr, db, descr);
        if (!obj) {
            debug_objects_enabled = 0;
            raw_spin_unlock_irqrestore(&db->lock, flags);
            debug_objects_oom();
            return;
        }
        debug_object_is_on_stack(addr, onstack);
    }

    switch (obj->state) {
    case ODEBUG_STATE_NONE:
    case ODEBUG_STATE_INIT:
    case ODEBUG_STATE_INACTIVE:
        obj->state = ODEBUG_STATE_INIT;
        break;

    case ODEBUG_STATE_ACTIVE:
        debug_print_object(obj, "init");
        state = obj->state;
        raw_spin_unlock_irqrestore(&db->lock, flags);
        debug_object_fixup(descr->fixup_init, addr, state);
        return;

    case ODEBUG_STATE_DESTROYED:
        debug_print_object(obj, "init");
        break;
    default:
        break;
    }

    raw_spin_unlock_irqrestore(&db->lock, flags);
}

void debug_object_init(void *addr, struct debug_obj_descr *descr)
{
    if (!debug_objects_enabled)
        return;

    __debug_object_init(addr, descr, 0);
}

void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
{
    if (!debug_objects_enabled)
        return;

    __debug_object_init(addr, descr, 1);
}

void debug_object_activate(void *addr, struct debug_obj_descr *descr)
{
    enum debug_obj_state state;
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;
    struct debug_obj o = { .object = addr,
                   .state = ODEBUG_STATE_NOTAVAILABLE,
                   .descr = descr };

    if (!debug_objects_enabled)
        return;

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (obj) {
        switch (obj->state) {
        case ODEBUG_STATE_INIT:
        case ODEBUG_STATE_INACTIVE:
            obj->state = ODEBUG_STATE_ACTIVE;
            break;

        case ODEBUG_STATE_ACTIVE:
            debug_print_object(obj, "activate");
            state = obj->state;
            raw_spin_unlock_irqrestore(&db->lock, flags);
            debug_object_fixup(descr->fixup_activate, addr, state);
            return;

        case ODEBUG_STATE_DESTROYED:
            debug_print_object(obj, "activate");
            break;
        default:
            break;
        }
        raw_spin_unlock_irqrestore(&db->lock, flags);
        return;
    }

    raw_spin_unlock_irqrestore(&db->lock, flags);
    /*
     * This happens when a static object is activated. We
     * let the type specific code decide whether this is
     * true or not.
     */
    if (debug_object_fixup(descr->fixup_activate, addr,
               ODEBUG_STATE_NOTAVAILABLE))
        debug_print_object(&o, "activate");
}

void debug_object_deactivate(void *addr, struct debug_obj_descr *descr)
{
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;

    if (!debug_objects_enabled)
        return;

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (obj) {
        switch (obj->state) {
        case ODEBUG_STATE_INIT:
        case ODEBUG_STATE_INACTIVE:
        case ODEBUG_STATE_ACTIVE:
            if (!obj->astate)
                obj->state = ODEBUG_STATE_INACTIVE;
            else
                debug_print_object(obj, "deactivate");
            break;

        case ODEBUG_STATE_DESTROYED:
            debug_print_object(obj, "deactivate");
            break;
        default:
            break;
        }
    } else {
        struct debug_obj o = { .object = addr,
                       .state = ODEBUG_STATE_NOTAVAILABLE,
                       .descr = descr };

        debug_print_object(&o, "deactivate");
    }

    raw_spin_unlock_irqrestore(&db->lock, flags);
}

void debug_object_destroy(void *addr, struct debug_obj_descr *descr)
{
    enum debug_obj_state state;
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;

    if (!debug_objects_enabled)
        return;

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (!obj)
        goto out_unlock;

    switch (obj->state) {
    case ODEBUG_STATE_NONE:
    case ODEBUG_STATE_INIT:
    case ODEBUG_STATE_INACTIVE:
        obj->state = ODEBUG_STATE_DESTROYED;
        break;
    case ODEBUG_STATE_ACTIVE:
        debug_print_object(obj, "destroy");
        state = obj->state;
        raw_spin_unlock_irqrestore(&db->lock, flags);
        debug_object_fixup(descr->fixup_destroy, addr, state);
        return;

    case ODEBUG_STATE_DESTROYED:
        debug_print_object(obj, "destroy");
        break;
    default:
        break;
    }
out_unlock:
    raw_spin_unlock_irqrestore(&db->lock, flags);
}

void debug_object_free(void *addr, struct debug_obj_descr *descr)
{
    enum debug_obj_state state;
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;

    if (!debug_objects_enabled)
        return;

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (!obj)
        goto out_unlock;

    switch (obj->state) {
    case ODEBUG_STATE_ACTIVE:
        debug_print_object(obj, "free");
        state = obj->state;
        raw_spin_unlock_irqrestore(&db->lock, flags);
        debug_object_fixup(descr->fixup_free, addr, state);
        return;
    default:
        hlist_del(&obj->node);
        raw_spin_unlock_irqrestore(&db->lock, flags);
        free_object(obj);
        return;
    }
out_unlock:
    raw_spin_unlock_irqrestore(&db->lock, flags);
}

void debug_object_assert_init(void *addr, struct debug_obj_descr *descr)
{
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;

    if (!debug_objects_enabled)
        return;

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (!obj) {
        struct debug_obj o = { .object = addr,
                       .state = ODEBUG_STATE_NOTAVAILABLE,
                       .descr = descr };

        raw_spin_unlock_irqrestore(&db->lock, flags);
        /*
         * Maybe the object is static.  Let the type specific
         * code decide what to do.
         */
        if (debug_object_fixup(descr->fixup_assert_init, addr,
                       ODEBUG_STATE_NOTAVAILABLE))
            debug_print_object(&o, "assert_init");
        return;
    }

    raw_spin_unlock_irqrestore(&db->lock, flags);
}

void
debug_object_active_state(void *addr, struct debug_obj_descr *descr,
              unsigned int expect, unsigned int next)
{
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;

    if (!debug_objects_enabled)
        return;

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (obj) {
        switch (obj->state) {
        case ODEBUG_STATE_ACTIVE:
            if (obj->astate == expect)
                obj->astate = next;
            else
                debug_print_object(obj, "active_state");
            break;

        default:
            debug_print_object(obj, "active_state");
            break;
        }
    } else {
        struct debug_obj o = { .object = addr,
                       .state = ODEBUG_STATE_NOTAVAILABLE,
                       .descr = descr };

        debug_print_object(&o, "active_state");
    }

    raw_spin_unlock_irqrestore(&db->lock, flags);
}

#ifdef CONFIG_DEBUG_OBJECTS_FREE
static void __debug_check_no_obj_freed(const void *address, unsigned long size)
{
    unsigned long flags, oaddr, saddr, eaddr, paddr, chunks;
    struct hlist_node *node, *tmp;
    HLIST_HEAD(freelist);
    struct debug_obj_descr *descr;
    enum debug_obj_state state;
    struct debug_bucket *db;
    struct debug_obj *obj;
    int cnt;

    saddr = (unsigned long) address;
    eaddr = saddr + size;
    paddr = saddr & ODEBUG_CHUNK_MASK;
    chunks = ((eaddr - paddr) + (ODEBUG_CHUNK_SIZE - 1));
    chunks >>= ODEBUG_CHUNK_SHIFT;

    for (;chunks > 0; chunks--, paddr += ODEBUG_CHUNK_SIZE) {
        db = get_bucket(paddr);

repeat:
        cnt = 0;
        raw_spin_lock_irqsave(&db->lock, flags);
        hlist_for_each_entry_safe(obj, node, tmp, &db->list, node) {
            cnt++;
            oaddr = (unsigned long) obj->object;
            if (oaddr < saddr || oaddr >= eaddr)
                continue;

            switch (obj->state) {
            case ODEBUG_STATE_ACTIVE:
                debug_print_object(obj, "free");
                descr = obj->descr;
                state = obj->state;
                raw_spin_unlock_irqrestore(&db->lock, flags);
                debug_object_fixup(descr->fixup_free,
                           (void *) oaddr, state);
                goto repeat;
            default:
                hlist_del(&obj->node);
                hlist_add_head(&obj->node, &freelist);
                break;
            }
        }
        raw_spin_unlock_irqrestore(&db->lock, flags);

        /* Now free them */
        hlist_for_each_entry_safe(obj, node, tmp, &freelist, node) {
            hlist_del(&obj->node);
            free_object(obj);
        }

        if (cnt > debug_objects_maxchain)
            debug_objects_maxchain = cnt;
    }
}

void debug_check_no_obj_freed(const void *address, unsigned long size)
{
    if (debug_objects_enabled)
        __debug_check_no_obj_freed(address, size);
}
#endif

#ifdef CONFIG_DEBUG_FS

static int debug_stats_show(struct seq_file *m, void *v)
{
    seq_printf(m, "max_chain     :%d\n", debug_objects_maxchain);
    seq_printf(m, "warnings      :%d\n", debug_objects_warnings);
    seq_printf(m, "fixups        :%d\n", debug_objects_fixups);
    seq_printf(m, "pool_free     :%d\n", obj_pool_free);
    seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
    seq_printf(m, "pool_used     :%d\n", obj_pool_used);
    seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
    return 0;
}

static int debug_stats_open(struct inode *inode, struct file *filp)
{
    return single_open(filp, debug_stats_show, NULL);
}

static const struct file_operations debug_stats_fops = {
    .open       = debug_stats_open,
    .read       = seq_read,
    .llseek     = seq_lseek,
    .release    = single_release,
};

static int __init debug_objects_init_debugfs(void)
{
    struct dentry *dbgdir, *dbgstats;

    if (!debug_objects_enabled)
        return 0;

    dbgdir = debugfs_create_dir("debug_objects", NULL);
    if (!dbgdir)
        return -ENOMEM;

    dbgstats = debugfs_create_file("stats", 0444, dbgdir, NULL,
                       &debug_stats_fops);
    if (!dbgstats)
        goto err;

    return 0;

err:
    debugfs_remove(dbgdir);

    return -ENOMEM;
}
__initcall(debug_objects_init_debugfs);

#else
static inline void debug_objects_init_debugfs(void) { }
#endif

#ifdef CONFIG_DEBUG_OBJECTS_SELFTEST

/* Random data structure for the self test */
struct self_test {
    unsigned long   dummy1[6];
    int     static_init;
    unsigned long   dummy2[3];
};

static __initdata struct debug_obj_descr descr_type_test;

/*
 * fixup_init is called when:
 * - an active object is initialized
 */
static int __init fixup_init(void *addr, enum debug_obj_state state)
{
    struct self_test *obj = addr;

    switch (state) {
    case ODEBUG_STATE_ACTIVE:
        debug_object_deactivate(obj, &descr_type_test);
        debug_object_init(obj, &descr_type_test);
        return 1;
    default:
        return 0;
    }
}

/*
 * fixup_activate is called when:
 * - an active object is activated
 * - an unknown object is activated (might be a statically initialized object)
 */
static int __init fixup_activate(void *addr, enum debug_obj_state state)
{
    struct self_test *obj = addr;

    switch (state) {
    case ODEBUG_STATE_NOTAVAILABLE:
        if (obj->static_init == 1) {
            debug_object_init(obj, &descr_type_test);
            debug_object_activate(obj, &descr_type_test);
            return 0;
        }
        return 1;

    case ODEBUG_STATE_ACTIVE:
        debug_object_deactivate(obj, &descr_type_test);
        debug_object_activate(obj, &descr_type_test);
        return 1;

    default:
        return 0;
    }
}

/*
 * fixup_destroy is called when:
 * - an active object is destroyed
 */
static int __init fixup_destroy(void *addr, enum debug_obj_state state)
{
    struct self_test *obj = addr;

    switch (state) {
    case ODEBUG_STATE_ACTIVE:
        debug_object_deactivate(obj, &descr_type_test);
        debug_object_destroy(obj, &descr_type_test);
        return 1;
    default:
        return 0;
    }
}

/*
 * fixup_free is called when:
 * - an active object is freed
 */
static int __init fixup_free(void *addr, enum debug_obj_state state)
{
    struct self_test *obj = addr;

    switch (state) {
    case ODEBUG_STATE_ACTIVE:
        debug_object_deactivate(obj, &descr_type_test);
        debug_object_free(obj, &descr_type_test);
        return 1;
    default:
        return 0;
    }
}

static int __init
check_results(void *addr, enum debug_obj_state state, int fixups, int warnings)
{
    struct debug_bucket *db;
    struct debug_obj *obj;
    unsigned long flags;
    int res = -EINVAL;

    db = get_bucket((unsigned long) addr);

    raw_spin_lock_irqsave(&db->lock, flags);

    obj = lookup_object(addr, db);
    if (!obj && state != ODEBUG_STATE_NONE) {
        WARN(1, KERN_ERR "ODEBUG: selftest object not found\n");
        goto out;
    }
    if (obj && obj->state != state) {
        WARN(1, KERN_ERR "ODEBUG: selftest wrong state: %d != %d\n",
               obj->state, state);
        goto out;
    }
    if (fixups != debug_objects_fixups) {
        WARN(1, KERN_ERR "ODEBUG: selftest fixups failed %d != %d\n",
               fixups, debug_objects_fixups);
        goto out;
    }
    if (warnings != debug_objects_warnings) {
        WARN(1, KERN_ERR "ODEBUG: selftest warnings failed %d != %d\n",
               warnings, debug_objects_warnings);
        goto out;
    }
    res = 0;
out:
    raw_spin_unlock_irqrestore(&db->lock, flags);
    if (res)
        debug_objects_enabled = 0;
    return res;
}

static __initdata struct debug_obj_descr descr_type_test = {
    .name           = "selftest",
    .fixup_init     = fixup_init,
    .fixup_activate     = fixup_activate,
    .fixup_destroy      = fixup_destroy,
    .fixup_free     = fixup_free,
};

static __initdata struct self_test obj = { .static_init = 0 };

static void __init debug_objects_selftest(void)
{
    int fixups, oldfixups, warnings, oldwarnings;
    unsigned long flags;

    local_irq_save(flags);

    fixups = oldfixups = debug_objects_fixups;
    warnings = oldwarnings = debug_objects_warnings;
    descr_test = &descr_type_test;

    debug_object_init(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
        goto out;
    debug_object_activate(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
        goto out;
    debug_object_activate(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_ACTIVE, ++fixups, ++warnings))
        goto out;
    debug_object_deactivate(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_INACTIVE, fixups, warnings))
        goto out;
    debug_object_destroy(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, warnings))
        goto out;
    debug_object_init(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
        goto out;
    debug_object_activate(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
        goto out;
    debug_object_deactivate(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_DESTROYED, fixups, ++warnings))
        goto out;
    debug_object_free(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
        goto out;

    obj.static_init = 1;
    debug_object_activate(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
        goto out;
    debug_object_init(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_INIT, ++fixups, ++warnings))
        goto out;
    debug_object_free(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_NONE, fixups, warnings))
        goto out;

#ifdef CONFIG_DEBUG_OBJECTS_FREE
    debug_object_init(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_INIT, fixups, warnings))
        goto out;
    debug_object_activate(&obj, &descr_type_test);
    if (check_results(&obj, ODEBUG_STATE_ACTIVE, fixups, warnings))
        goto out;
    __debug_check_no_obj_freed(&obj, sizeof(obj));
    if (check_results(&obj, ODEBUG_STATE_NONE, ++fixups, ++warnings))
        goto out;
#endif
    printk(KERN_INFO "ODEBUG: selftest passed\n");

out:
    debug_objects_fixups = oldfixups;
    debug_objects_warnings = oldwarnings;
    descr_test = NULL;

    local_irq_restore(flags);
}
#else
static inline void debug_objects_selftest(void) { }
#endif

/*
 * Called during early boot to initialize the hash buckets and link
 * the static object pool objects into the poll list. After this call
 * the object tracker is fully operational.
 */
void __init debug_objects_early_init(void)
{
    int i;

    for (i = 0; i < ODEBUG_HASH_SIZE; i++)
        raw_spin_lock_init(&obj_hash[i].lock);

    for (i = 0; i < ODEBUG_POOL_SIZE; i++)
        hlist_add_head(&obj_static_pool[i].node, &obj_pool);
}

/*
 * Convert the statically allocated objects to dynamic ones:
 */
static int __init debug_objects_replace_static_objects(void)
{
    struct debug_bucket *db = obj_hash;
    struct hlist_node *node, *tmp;
    struct debug_obj *obj, *new;
    HLIST_HEAD(objects);
    int i, cnt = 0;

    for (i = 0; i < ODEBUG_POOL_SIZE; i++) {
        obj = kmem_cache_zalloc(obj_cache, GFP_KERNEL);
        if (!obj)
            goto free;
        hlist_add_head(&obj->node, &objects);
    }

    /*
     * When debug_objects_mem_init() is called we know that only
     * one CPU is up, so disabling interrupts is enough
     * protection. This avoids the lockdep hell of lock ordering.
     */
    local_irq_disable();

    /* Remove the statically allocated objects from the pool */
    hlist_for_each_entry_safe(obj, node, tmp, &obj_pool, node)
        hlist_del(&obj->node);
    /* Move the allocated objects to the pool */
    hlist_move_list(&objects, &obj_pool);

    /* Replace the active object references */
    for (i = 0; i < ODEBUG_HASH_SIZE; i++, db++) {
        hlist_move_list(&db->list, &objects);

        hlist_for_each_entry(obj, node, &objects, node) {
            new = hlist_entry(obj_pool.first, typeof(*obj), node);
            hlist_del(&new->node);
            /* copy object data */
            *new = *obj;
            hlist_add_head(&new->node, &db->list);
            cnt++;
        }
    }
    local_irq_enable();

    printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
           obj_pool_used);
    return 0;
free:
    hlist_for_each_entry_safe(obj, node, tmp, &objects, node) {
        hlist_del(&obj->node);
        kmem_cache_free(obj_cache, obj);
    }
    return -ENOMEM;
}

/*
 * Called after the kmem_caches are functional to setup a dedicated
 * cache pool, which has the SLAB_DEBUG_OBJECTS flag set. This flag
 * prevents that the debug code is called on kmem_cache_free() for the
 * debug tracker objects to avoid recursive calls.
 */
void __init debug_objects_mem_init(void)
{
    if (!debug_objects_enabled)
        return;

    obj_cache = kmem_cache_create("debug_objects_cache",
                      sizeof (struct debug_obj), 0,
                      SLAB_DEBUG_OBJECTS, NULL);

    if (!obj_cache || debug_objects_replace_static_objects()) {
        debug_objects_enabled = 0;
        if (obj_cache)
            kmem_cache_destroy(obj_cache);
        printk(KERN_WARNING "ODEBUG: out of memory.\n");
    } else
        debug_objects_selftest();
}