How can I know what is tainting my kernel

Two questions about taint system.. 1. I have a installation of archlinux with kernel 3.0, just after boot I cat /proc/sys/kenrel/tainted and receives 1024, but cat /var/log/messages | grep -i taint gives me no output. How can I know what is tainting my kernel? 2. I was studying char devices, and have writed some code. I have put the MODULE_LICENSE("GPL"); on the module, build it, put it on a initrd image and boot with qemu using -kernel and -initrd options. When I loadit with modprobe I receives a message on console saying that kernel was tainted and /proc/sys/kernel/tainted gives me 4024. There is any other thing on module, besides license that can taint the kernel? Here is the code -> http://sprunge.us/RHNa?c []'s