Comment 14 for bug 779753

Same problem on Thinkpad R400 @ 11.04. Upgrading to kernel 2.6.39 did not resolve the problem.

Kworker threads (4 of them) suddenly consume all CPU resources. Sometimes the system recovers, sometimes it blocks for > 5 minutes, i.e. until I flip the switch.

This happens on an fresh, out-of the box installation. However, the first few reboots / hibernation / suspend-cycles do not yield the issue; the problem appears after a few hours to days of usage - perhaps in conjunction with inserting a USB device (mobile broadband, anyone?) and / or configuring Network / WIFI connections. I will re-install once more and test, recording perfdata using the "ridiculous" method Linus suggested:

   perf record -ag sleep 10
   perf report

 (see https://lkml.org/lkml/2011/3/30/836)

Seems this is completely kernel / driver -related, since multiple distros are affected.