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After I updated my kernel I restarted my computer (as it always requests) and now I can't log in (I can't get past the login screen). The resolution of the screen at login has also changed, leaving me to believe that the video driver I normally used was changed.

As I boot up the computer the screen at one point is momentarily black and displays the following messages:

[ 7.635692] nvidia: version magic '4.4.0-113-generic SMP mod_unload modversions 686 ' should be '4.4.0-113-generic SMP mod_unload modversions 686 retpoline '

[ 7.788685] nvidia: version magic '4.4.0-113-generic SMP mod_unload modversions 686 ' should be '4.4.0-113-generic SMP mod_unload modversions 686 retpoline '

Any suggestions as to what I can do to fix this issue? I am a novice when it comes to Ubuntu, so any help is greatly appreciated!

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  • 1
    Retpoline is the Spectre patch. In grub Advanced Options menu select Kernel 4.4.0-112 to boot with. Feb 9, 2018 at 23:08
  • Your advice worked at first. After I booted up from Kernel 4.4.0-112, I was able to get past the login screen. To make sure it was a permanent fix, I rebooted my computer with the 4.4.0-112 Kernel and now it's giving me the same problem.
    – KJFS
    Feb 10, 2018 at 0:01
  • Are you sure when you rebooted you didn't take the Ubuntu main option by muscle memory? Feb 10, 2018 at 0:04
  • I chose the 4.4.0-112 main (not the recovery) option the first time. During my second boot, I chose the same and it gave me my afformentioned issue. I tried the recovery option afterwards, but I didn't know how to use it, so I just resumed the boot process. Please forgive me, I should have mentioned in my question that I'm still a novice when it comes to Ubuntu. I'll add it now.
    – KJFS
    Feb 10, 2018 at 0:10
  • 2
    Someone has reported this upstream: bugs.launchpad.net/ubuntu/+source/xorg/+bug/1750937
    – Cheetah
    Feb 22, 2018 at 3:43

1 Answer 1

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I solved the problem by following this post from the bugs launchpad. In summary:

Run the following command and look for the vermagic line:

modinfo nvidia-384 -k 4.4.0-116-generic

It will probably say: vermagic: 4.4.0-116-generic SMP mod_unload modversions. Here the retpoline string is missing. You can fix this by removing and re-building the module with DKMS

sudo dkms remove nvidia-384/384.111 -k 4.4.0-116-generic
sudo dkms install nvidia-384/384.111 -k 4.4.0-116-generic

After that the modinfo command will show vermagic: 4.4.0-116-generic SMP mod_unload modversions retpoline

If you are using custom version of gcc this post is also relevant:

If you are using a Ubuntu version of gcc, then gcc probably updated when you got the newer kernel. The changes to gcc necessary to support retpoline should have been backported to most active versions of gcc. However if you have installed a custom version of gcc then your kernel module probably will not build correctly.

So if the above procedure does not work you may have to check which gcc version you are using.

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