debugobjects.c

Lib files of linux kernel

	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);
}

/*
 * 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_enabled = 0;
	else
		debug_objects_selftest();
}