I am experiencing occasional system freezes with Ubuntu 16.04 using the Gnome 3 Desktop. The logging output in
/var/log is not really helpful. There are no files in
/var/crash. I have not been able to identify a pattern in the last log entries before the freeze. I would like to investigate the problem further or file a bug report, but I ran out of ideas how to track it down. Here are the symptoms (similar to those Mysterious minutes-long system freeze):
- The UI freezes except the mouse cursor, which still responds with a latency of several seconds (it jumps roughly in the direction of the mouse movement).
- The system usually does not respond to keyboard input. Sometimes I was able to
ctrl-alt-f1to the console, but I was rarely able to login. I never succeeded to execute a command (e.g.
sudo init 6). Even
sysrq-owould not work.
- The HDD LED is illuminated constantly.
- Judging by the fan speed, the CPU runs under high load.
The only recovery is a hard reset/reboot. I am suspecting that the freezes occured in the following situations:
- High memory usage
- A VirtualBox VM (windows guest) is running or has been running for a while (e.g. several days)
However, the logfiles give no hints in that direction. There are for example no messages of the OOM killer. How should I proceed to identfy the exact error conditions?