I dual-boot MacIntel Core 2 duo. nVidia graphics.
Ran upgrade from ubuntu 13.10 to 14.04 (64 bit). On restart ran into
{numbers} Bug: soft lockup - CPU#0 stuck for 22s! [swapper/0:1]
Tried loading earlier kernel: same problem
Tried re-installing ubuntu from a liveCD that has worked in the past:
version 13.04. Same problem.
Tried re-partitioning hard drive using Mac OS X disk utility and then
installing ubuntu 14.04LTS from liveCD. Same problem. Not possible
to verify liveCD disk (creates same "soft lockup" bug.)
Tried installing from the liveCD with version 13.04 that I know works (that's how I got Ubuntu on this machine in the first place.) Same problem.
I know this is not a hardware problem as OS X works just fine, I am using it right now on the same machine. I have been using various versions of Ubuntu for 2 years.
Things I cannot do:
Open a terminal
Verify CD image
Start ubuntu from CD (same soft lockup problem)
This problem is similar to some other questions, none of which have been satisfactorily answered:
Ubuntu 14.04 soft lockup on Vostro 3500
Cannot do fresh install of Ubuntu 13.04 while booting from DVD: "soft lockup" bug
Live CD stalls when installing Ubuntu 13.10
UPDATE 6/11/14:
Following some much-appreciated advice from bain (see below) I burned a 12.04LTS disk and started with kernel parameters:
noapic, no1apic, acpi=off, nomodeset, elevator=deadline, and clocksource=jiffies.
With all of these parameters I was able to load the 12.04LTS CD ("Try without installing"). It worked fine.
However, as soon as I tried to install Ubuntu from the CD, my wired ethernet (eth0) connection would hang. There are already various askubuntu questions and bug reports about this problem, none of which had answers for me. (E.g., dhclient eth0 does nothing, none of the various reset commands does anything, manually setting IP &etc does nothing. I could reliably kill the ethernet connection by clicking "install ubuntu" every single time.)
I could go ahead and install 12.04 without an internet connection, but the install would freeze after mostly completing (I tried several times.)
There were some relevant error messages in the details of the install output script that, IIRC, had to do with searching for missing files and not being able to access eth0 (internet) to get them. To be honest I gave up at that point and I'm not sure I wrote those down. If I find some notes I will post them.
At this point I no longer have Ubuntu on my system. I wiped the partitions and am using exclusively OS X. I am leaving this question in case it helps anyone else with similar problems. I love open source and I love Linux, and the next machine I get I will probably just build from Arch. At the moment I miss repositories and a lot of other things about Ubuntu, but the OS X terminal is 'nix, I can pretty much use all the open source apps I like, and while I am not a fan of the Apple software it gets the job done for me. Unlike Ubuntu, which can't even install.
I realize this isn't necessarily a place for a soapbox speech, but when I first installed 12.04 several years ago there were already people in the community complaining that Canonical was going too "commercial". But I loved it. Several years later and all I've seen is Canonical adding more not-so-useful bells and whistles to Ubuntu while continually failing to fix basic problems on upgrades. With a dual-boot (and sometimes triple-boot) system it always took me some tweaking to get an upgrade to work, and to some extent that is okay. But at this point I feel like Canonical ought to just put a price tag on Ubuntu. All I see is more commercialism and advertising and product tie-ins, and ongoing problems do not get fixed. I am a big fan of open-source, not-for profit enterprise. I am also a big fan of for-profit enterprise, which certainly has its place and usefulness. I am not a fan of companies who pretend to be in favor of open source but really are just out to make a buck, and IMNSHO that is what Canonical has become.
This is a great community and I wish you all the best, but my next install of Linux will not be Ubuntu.