Actually, I have now found out that my problem was caused by the built-in SD card reader. The [17179611.784000] BUG: soft lockup detected on CPU#0! message (and freeze) appears during boot-up if an SD card is present in the SD card reader.
-Christopher -- CPU soft lockup during bootup https://launchpad.net/bugs/63418 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs