Further tests on my systems have shown that the oops is caused on loading the SMART2 part. I've compiled a kernel without it, and so far it's running ... The bad thing about this is that neither I can test the SMART2 part nor such a controller is available to me any longer. I can't even tell you when this problem was introduced because I used the mainline-kernel before. So I've got no clue what to do with this bug now. Cheers Helmut