I have the same problem here, also with a Thinkpad X60s. This looks like an old bug was reintroduced into the kernel. I've seen the same behaviour some time ago, it was related to the sata controller timing out, when trying to detect disks. See point 2 in http://lkml.org/lkml/2006/1/12/461, I don't when this was fixed but some kernel update did it.
-- mounting root filesystem stuck https://launchpad.net/bugs/50313 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
