#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kref.h>

static void reftst_release(struct kref *ref)
{
	printk(KERN_INFO "released %p\n", ref);
}

static void reftst_static_simple_test(void)
{
	struct kref test;
	printk(KERN_INFO "RefTest - Static\n");
	kref_init(&test);
	kref_get(&test);
	kref_put(&test, reftst_release);
	kref_put(&test, reftst_release);
}

static void reftst_static_watermark_test(void)
{
	struct kref test;
	printk(KERN_INFO "RefTest - Watermark test\n");
	kref_init(&test);
	kref_set(&test, 0x6b6b6b6b);
	kref_put(&test, reftst_release);
}

struct reftst_struct {
	u8 redzone[32];	/* or just 8 */
	struct kref ref;
	u8 redzone2[32];
};

static void reftst_static_poison_test(void)
{
	struct reftst_struct *test = kzalloc(sizeof(*test), GFP_KERNEL);

	if (!test)
		return;

	printk(KERN_INFO "RefTest - slXb poison test\n");
	kref_init(&test->ref);
	
	kfree(test);

	/* this is illegal, "test" is already freed... so it could oops here */
	kref_put(&test->ref, reftst_release);
}

static int __init reftst_init(void)
{
	printk(KERN_INFO "RefTest\n");
	reftst_static_simple_test();
	reftst_static_watermark_test();
	reftst_static_poison_test();
	
	return 0;
}

static void __exit reftst_exit(void)
{
	
}

module_init(reftst_init);
module_exit(reftst_exit);
MODULE_LICENSE("GPL");