Ubuntu 18.04 Linux Kernel Update Causes Boot Delays Of 4 Minutes Or More On Some Systems

A Linux Kernel bug found in a recent Ubuntu 18.04 update is causing very slow boot times (of around 4 minutes or even more) on some systems.

The kernel image that caused the issue (version 4.15.0-24) was released as an update to Ubuntu 18.04 on July 4th, and was already removed from the repository archives at the time I'm posting this article.

A fix for this issue was already released, but the updated package is currently only available in the Ubuntu 18.04 proposed repositories - hopefully it will make it into the main repositories soon.

An user mentions that booting to previous kernels apparently doesn't solve this, though that is probably a different issue.

Until the package containing the fix is promoted from the Proposed repository, if you're affected by this bug (which seems to be entropy-related) you can speed up the boot process by "wiggling the mouse (or a finger on the touchpad) or hitting the shift or ctrl key during boot to make the system generate entropy a bit faster", mentioned Oliver Grawert in a Google+ reply.

This bug does not affect all systems. In fact,  I'm running this kernel right now and I'm not noticing any increased boot times on my Ubuntu 18.04 desktop:

Update: a new kernel was pushed as an update which should hopefully fix this issue.