Ubuntu Bionic 18.04 SoftwareUpdater this morning installed updates including a new kernel version 4.15.0-24-generic #26-Ubuntu. Now when the system boots the screen displays the content of some log instead of the login prompt.
The log file is displayed after the normal red dots phase, except that there is a long pause after the 4th dot becomes red and the fifth dot never becomes red. Suddenly this log is displayed. Almost everything in it is [ OK ].
The last 3 lines of this log read
[ OK ] Started irqbalance daemon
[ OK ] System Logging Service.
[ OK ] Started GNOME DisplayManager. Dispatcher Service....upport.hanges.pp link was shut down.
Further up is one non-OK line that might be related, but later in the line there is [ OK ]. Maybe the "Plymouth BootScreen" it refers to is what I am seeing.
[ .] A start job is running for Hold until boot process finishes up (28s / no limit)[ OK ] Started Show Plymouth BootScreen.
I tried booting the previous kernel but the same thing happens.
I am unable to scroll up to see the beginning of this log.
How can I get my system to boot properly and show the login screen?
I can ssh into the system so if I know what to change to fix this, I should be able to do it.
This is the latest in a depressingly long list of Ubuntu software updates that have ****ed up my system. It's no wonder users are reluctant to install updates.
I found Launchpad bug 1779476, opened 6/30, which matches this problem.
EDIT: Bug 1779476 is a different problem with similar symptoms. Bug 1779827 has matching symptom and cause.
Best Answer
Give this a try:
This issue only seems to affect kernel 4.15.0-24. getrandom() is called when starting Xorg and for some reason in 4.15.0-24, it hangs for a bit until the entropy is high enough to generate a random number to use as a magic cookie for xauth. Xorg, LightDM, and GDM won't start until xauth is given a random number to use. Any kind of mouse/keyboard input probably raises entropy, which explains why pressing keys or moving the mouse fixes the problem. Haveged generates enough entropy at boot, eliminating the problem.
It's been reported as a bug, so hopefully haveged won't be necessary in future kernels once the bug is fixed.
The previous 4.15.0-23 kernel doesn't have this problem, so booting into that instead would also work.
EDIT: According to this bug report a fix has been committed. I would imagine it'll be released to the repo soon.