Merge git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6

[mirror_ubuntu-zesty-kernel.git] / lib / debugobjects.c

/*
 * Generic infrastructure for lifetime debugging of objects.
 *
 * Started by Thomas Gleixner
 *
 * Copyright (C) 2008, Thomas Gleixner <tglx@linutronix.de>
 *
 * For licencing details see kernel-base/COPYING
 */
#include <linux/debugobjects.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>
#include <linux/debugfs.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;
        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_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 int 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 obj_pool_free;

        if (unlikely(!obj_cache))
                return obj_pool_free;

        while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {

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

                spin_lock_irqsave(&pool_lock, flags);
                hlist_add_head(&new->node, &obj_pool);
                obj_pool_free++;
                spin_unlock_irqrestore(&pool_lock, flags);
        }
        return obj_pool_free;
}

/*
 * 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;

        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;
                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;
        }
        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;

        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.
                 */
                spin_unlock_irqrestore(&pool_lock, flags);
                kmem_cache_free(obj_cache, obj);
                spin_lock_irqsave(&pool_lock, flags);
        }
        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;

        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 = !work_pending(&debug_obj_work);
        hlist_add_head(&obj->node, &obj_pool);
        obj_pool_free++;
        obj_pool_used--;
        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++) {
                spin_lock_irqsave(&db->lock, flags);
                hlist_move_list(&db->list, &freelist);
                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)
{
        static int limit;

        if (limit < 5 && obj->descr != descr_test) {
                limit++;
                WARN(1, KERN_ERR "ODEBUG: %s %s object type: %s\n", msg,
                       obj_states[obj->state], obj->descr->name);
        }
        debug_objects_warnings++;
}

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

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);

        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;
                        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;
                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;
        }

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

/**
 * debug_object_init - debug checks when an object is initialized
 * @addr:       address of the object
 * @descr:      pointer to an object specific debug description structure
 */
void debug_object_init(void *addr, struct debug_obj_descr *descr)
{
        if (!debug_objects_enabled)
                return;

        __debug_object_init(addr, descr, 0);
}

/**
 * debug_object_init_on_stack - debug checks when an object on stack is
 *                              initialized
 * @addr:       address of the object
 * @descr:      pointer to an object specific debug description structure
 */
void debug_object_init_on_stack(void *addr, struct debug_obj_descr *descr)
{
        if (!debug_objects_enabled)
                return;

        __debug_object_init(addr, descr, 1);
}

/**
 * debug_object_activate - debug checks when an object is activated
 * @addr:       address of the object
 * @descr:      pointer to an object specific debug description structure
 */
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;

        if (!debug_objects_enabled)
                return;

        db = get_bucket((unsigned long) addr);

        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;
                        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;
                }
                spin_unlock_irqrestore(&db->lock, flags);
                return;
        }

        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.
         */
        debug_object_fixup(descr->fixup_activate, addr,
                           ODEBUG_STATE_NOTAVAILABLE);
}

/**
 * debug_object_deactivate - debug checks when an object is deactivated
 * @addr:       address of the object
 * @descr:      pointer to an object specific debug description structure
 */
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);

        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:
                        obj->state = ODEBUG_STATE_INACTIVE;
                        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");
        }

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

/**
 * debug_object_destroy - debug checks when an object is destroyed
 * @addr:       address of the object
 * @descr:      pointer to an object specific debug description structure
 */
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);

        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;
                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:
        spin_unlock_irqrestore(&db->lock, flags);
}

/**
 * debug_object_free - debug checks when an object is freed
 * @addr:       address of the object
 * @descr:      pointer to an object specific debug description structure
 */
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);

        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;
                spin_unlock_irqrestore(&db->lock, flags);
                debug_object_fixup(descr->fixup_free, addr, state);
                return;
        default:
                hlist_del(&obj->node);
                spin_unlock_irqrestore(&db->lock, flags);
                free_object(obj);
                return;
        }
out_unlock:
        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;
                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;
                                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;
                        }
                }
                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);
                        /*
                         * Real code should return 0 here ! This is
                         * not a fixup of some bad behaviour. We
                         * merily call the debug_init function to keep
                         * track of the object.
                         */
                        return 1;
                } else {
                        /* Real code needs to emit a warning here */
                }
                return 0;

        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
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);

        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:
        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++)
                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 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++;
                }
        }

        printk(KERN_DEBUG "ODEBUG: %d of %d active objects replaced\n", cnt,
               obj_pool_used);
        local_irq_enable();
        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();
}