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.

7 comments:

  1. I had same problem on linuxmint 19 with 4.15.0-24, 4.15.0-20 is OK.

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  2. You can move mouse or increase entropy in system.

    sudo apt install haveged

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  3. sudo apt install rng-tools

    rng-tools installs the rngd daemon which will feed the kernel number generator from HW entropy sources, such as HW random number generators from Intel and AMD CPUs.

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  4. On my wife's laptop we decreased the wait time to a couple seconds by using tunefs to run fsck at every bootup,

    example for /dev/hda1 -c 1 makes it scan at every boot

    sudo tune2fs -c 1 /dev/hda1

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  5. I have this exact issue with ANY kernel above 4.15.0-20. I tried over a dozen different versions higher and ONLY 4.15.0-20 works straight away. So I seriously doubt its an issue with just 4.15.0-24, at least on my machine.

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