Long freeze at startup

[Ocirne94]

Hello all,
I have Kubuntu 12.04.4 (Linux 3.8.0-35) and my problem is that as soon as the first frame of the workspace is shown the desktop environment freezes: I can still move the mouse, but everything is locked up and no redrawing happens.
But the system is not frozen: the console (ctrl-alt-F1) works perfectly. Getting back to the screen (ctrl-alt-F8) instead leads to black screen (with bottom bar). After some minutes (5-10) the workspace starts working as normal.
This happens with both nvidia and vesa drivers.
An interesting thing is that during the freeze I cannot run command ls on my home directory: it doesn't return any output, just like an infinite sleep command. Accessing files and directories within the home directory instead works just fine. All other commands do, too. When the freeze ends, instead, I can run ls with no problems.
I suppose it might be a KDE process accessing the home directory and trying to perform some long task on it (it's >600 GB and >1.2M files), and it freezes everything else while doing so.
I've tried with XFCE environment and there is no freeze.

Any tips?
Thank you in advance for your time,
Ocirne

[SteveRiley]

Please try a more recent version than 12.04. That's pretty old by now and it has been plagued by freezes on certain hardware that ultimately don't admit of any particular resolution. For example, Launchpad bug 993187 was the one I could never work around. When 12.10 came, I was so happy.

[Ocirne94]

Hi, thank you for your answer.
I'm on LTS versions only, so 2 little months more to wait before update. What I must say is that the freezes have begun quite recently - have been around for a couple months now - and I've had 12.04 since it was released, so it must be a recent update... or not?

[vinnywright]

are you running out of space in /home or / ,,,,,,, go to the console log in as you and run "top" ,,,,is anything eating up the CPU or RAM ?

VINNY

[SteveRiley]

I'm on LTS versions only, so 2 little months more to wait before update.

Unless you have a policy that requires staying on LTS, there's really no reason to. Many improvements have landed in various bits of the operating system over time. "LTS" does not in any sense indicate or imply a higher quality than interim releases.

[GreyGeek]

That problem, and a concurrent one caused by an update which made my AT9462 wireless connection spotty and slow, forced me to leave 12.04.
In my situation I could still move the mouse and the keyboard would respond to Alt-F2, but the desktop and all open apps froze. At least I could open Sysmonitor and then send the plasma-desktop widget an INT signal, which would break it free and allow me to continue to use it for 10 or 15 minutes before it would lock up again. The wifi situation was intolerable and my research indicated that a more recent kernel would help, so I scouted around and replaced Kubuntu 12.04 with KWheezy 1.4, which was an excellent distro based on Debian Wheezy and with the 3.9 kernel, which solved my wifi connection problem and, at the same time, cleared up the desktop freezes. When Kubuntu 14.04 went Alpha, two months after I switched to KWheezy I ran its in LiveCD mode and found that it solved my problems, so I replaced KWheezy with Trusty Tahr and couldn't be happier. The only problem Tahr gave me is that under certain simultaneous mouse movements and clicks (mouse move and mouse down events) FireFox will lock up, but a recent update seems to have eliminated that problem.

[Ocirne94]

Hi all,
thank you for your answers.

are you running out of space in /home or / ,,,,,,, go to the console log in as you and run "top" ,,,,is anything eating up the CPU or RAM ?

I have 300 GB free, should be enough. top (and htop, which I prefer) show no heavy processes running; plasma-desktop eats 2.5% RAM and 1% CPU. Less than 1 GB of total memory usage. And there is no apparent change when the freeze ends.

Unless you have a policy that requires staying on LTS, there's really no reason to. Many improvements have landed in various bits of the operating system over time. "LTS" does not in any sense indicate or imply a higher quality than interim releases.

Yep, it's a policy: my PC is in a network where the server mirrors the repos - only the LTS ones. So I'll eagerly wait for final 14.4.

As a side note, I've found out that also the df command is locked (like ls is) during the freeze. But the disk activity LED on the chassis is off...

Ocirne