“kernel: serial8250: too much work for irq4” potential problem caused by Azure OMS Agent

Problem:

There are a lot of warnings “kernel: serial8250: too much work for irq4 ” in /var/log/messages and are likely your system experiences stability problems. And can lead to Oracle cluster node evictions.

Cause:

The problem was related to Azure OAM Agent pushing very large messages to serial console. The problem was introduced by the latest update of the Azure OMS agent.

Temporary Solution:

Temporarily remove OMS Linux Agent Extension until Microsoft resolves this bug:

1. On Azure portal click the link of the affected VM.
2. Click the “Extensions” section.
3. Click the OMS Linux Agent in the list.
4. Click the “Uninstall” button at the top

When you make sure that OMS agent bug is fixed (should be verified with Microsoft support), then you can reinstall the pluggin.