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I tried to upgrade from 16.04LTS to 17.10 and got this.

enter image description here

What have I done wrong?

karel
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Mike
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    That appears to be a kernel error, boot an old kernel – Panther Oct 25 '17 at 15:21
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    I don’t have an old kernel. After the ugrade failure I couldn’t reboot so i did a HD reformat and did a clean install. Tried that half a dozen times with the same fatal error result so gave up. Where do i get an old kernel. Will reinstalling 16.04LTS get me up and running again? – Mike Oct 26 '17 at 00:31
  • Voted to close as irreproducible because the problem was solved by reinstalling the OS. – karel Nov 27 '17 at 23:42

2 Answers2

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Definitely a kernel problem, the text you're seeing is a logged stacktrace after a kernel panic. Specifically, the kernel panic appears to be caused by something wrong with the rtlwifi (Realtek Wifi) module. Blacklist that module through the GRUB command line to successfully boot into your Ubuntu installation, then try your luck installing newer or older kernels. Here's how:

When the GRUB loader appears, select Advanced Options for Ubuntu and press e to edit the boot line. On the kernel command/boot line that says something like linux /boot/vmlinuz-linux root=UUID=978e3e81-8048-4ae1-8a06-aa727458e8ff quiet splash, append the following text exactly: modprobe.blacklist=rtlwifi then press Ctrl+x to boot with the module blacklisted. If you end up with the same kernel panic, then also try blacklisting the mac80211 module with the modprobe.blacklist=rtlwifi,mac80211.

That should at the very least enable you to actually boot into Ubuntu 17.10. Now you need manually install an older or newer kernel. First, try the newest kernel v4.14.2 http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.14.2/, where perhaps that bug has been fixed. If you get the same kernel panic on bootup using the newer kernel, try the latest version of the lts stable kernel: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.9.65/

Considering it's the module your Realtek wifi card probably uses, you will be unable to access the internet and must load the debian packages from the mainline kernel repository onto a USB key. Manually install the kernel using dpkg with the precompiled debian packages (you most likely need the headers all, headers generic amd64 and image generic amd64 .debs) at the Ubuntu mainline kernel repository: http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D

Inside your installation of Ubuntu, navigate to the downloads folder and manually install the .deb packages using sudo dpkg -i *.deb. Fiddle around and try to find the latest version of the kernel you can run until you receive a kernel panic. Then file a bug on launchpad for the Ubuntu kernel maintainers or directly with the kernel bug tracker at https://bugzilla.kernel.org/.

Nicholas Stommel
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Booted up with a fresh LiveCD. Overwrote the old system. All fixed.

Mike
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  • Interesting...considering that the modified 4.13.x kernel you upgraded to in your transition from 16.04 to 17.10 is the same one on the installation disk. Well, if it happens again, at least you know what to do blacklisting the affected module during bootup. Considering you ended up with a repeated full-blown kernel panic, I'm curious whether or not your system will remain 'fixed'. – Nicholas Stommel Nov 28 '17 at 01:02
  • Your 1st post is useful in case of futire issues. The problem i had started after I upgraded from 16.04 to 17.10. When i rebooted as instructed the pc hung for about 5 minutes then the screenshot in my original question appeared. Your answer instructed the procedure following the appearance of Grub but it never appeared - just a flashing cursor then the same fatal result. I tried to reinstall 16.04 from the original .iso download but all i got was a flashing cursor not even the fatal error. I didnt lose any important stuff this time. Will try the upgrade to 17.10 again now. – Mike Nov 28 '17 at 04:05