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This entry has been published on 2014-05-24 and may be out of date.

Last Updated on 2014-05-24.

Problem / Scenario

Backup Software like Acronis Backup & Recovery causes your Hyper-V Virtual Machines to freeze. Guest OS is Ubuntu.

Sometimes this also happens when you restart your Hyper-V host or make a snapshot of your VM.

The VM itself displays error messages like “BUG: scheduling while atomic”.

Solution

The error message led me to this site, where it is mentioned that the error should have been fixed for about over a year now. I also tried to add the -Proposed entry in sources.list, but it did not help.

I upgraded to the latest Ubuntu Server version (14.04 LTS at the moment), but it did not help.

The final problem was I always left the Ubuntu default wizard setting by default (keep current file) when it asks for the boot / grub settings (menu.1st). So the system kept booting from an older kernel. In my case it was a 3.0 kernel, but in the meantime there exists version 3.13.

Additionally, as far as I know, Ubuntu will not always upgrade to the latest kernel itself by doing a distro upgrade.

Steps I did to solve the problem:

  1. For safety reasons: VM snapshot or VHD copy
  2. apt-get install linux-image-generic
  3. apt-get autoremove
  4. After the first or second step the wizard should ask you whether you want to keep your boot menu file. Choose the first option here (use a “new” one from the distributor).
  5. Reboot and check the current kernel version (in the login info message or type uname -r).