Tips and tricks: Why does my system sometimes hang at the end of reboot or shutdown?

I have noticed that my Red Hat Enterprise Linux 5 and/or Red Hat Enterprise Linux 5.1 system very occasionally hang at the end of the reboot / shutdown process. What can I do to avoid this?

This issue affects Red Hat Enterprise Linux 5 releases before Red Hat Enterprise Linux 5.2 and is due to a bug in cpufreq locking that may deadlock when the modules are unloaded, which is what happens at reboot and shutdown very late in the process.

To resolve this issue, update the systems kernel to at least the Red Hat Enterprise Linux 5.2 kernel. Alternatively, work around the problem by disabling cpuspeed with:

# chkconfig cpuspeed off
# service cpuspeed stop

This does means the loss of some energy efficiency.

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This entry was posted by the editorial team on Monday, March 3rd, 2008 at 2:42 pm and is filed under tips and tricks. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.