Kernel null pointer dereference - Lenovo Thinkpad USB-C Dock Gen2

Dear All,

I am a new Manjaro user, I used arch a few years ago on a headless raspberry pi and was very happy with it, but the stability of auto updates were a concern for using as a primary distro. Now I’ve looked up and Manjaro seems to be safe for day-to-day productivity/development, thus I decided to give it a try.

I am having issues with a dock I have at work, where upon connecting my computer to it, it freezes after about a minute. I managed to find that it is being caused by a Kernel null pointer dereference, according to the title. I took a photo with my phone to provide info about the issue. Please let me know if there is any log I can collect to further improve the characterization of the issue.

Thank you all for your attention, time and help!

Best regards,


It seems I am too junior to embed media in a post, thus I shared with photos at:

Are you on kernel version 5.6 as indicated in your profile?
If so, try another one like 5.7 and 5.8…

Yes, tried with 5.7 after creating my profile and updating. It seems that there is a patch available at: lkml dot org/lkml/2020/7/26/24/ but it has not been merged in master yet.

kudos for finding this. Then you’d either need to wait until it’s implemented or build you own kernel including the path I guess.

I would appreciate if anyone could guide me on how to build the kernel in Manjaro, it seems that things are a little different as pkgbuild is used. I must confess I am not familiar with it. Any link to a guide or walk-through would be greatly appreciated.

You clone the git repo with the kernel (in this case git clone to your PC.

Then you make a new file with the contents of the patch in that folder, e.g. “lenovo-fix-dock.patch”. Copy paste the code from your link into it, beginning with “diff --git…”.

Then you edit PKGBUILD and add the filename (‘lenovo-fix-dock.patch’) to the source=( tag at the end of the list.

Then you add a line at the end of the sha256sums=( tag with the sha256sum of your patch file (or if you are lazy like me just put ‘SKIP’ instead (since you know the code you put into the patch, right :wink: )))

Finally you increase pkgrel= in that file with 1 (if it is 2, make it 3)

Save that file and enter makepkg into the terminal.
That should compile the package. this will take a while (and hopefully not crash :wink: )

Afterwards you can doubleclick on the generated .xz file to install it with pamac.

Or just wait until some stupid other guy compiles it for you

currently compiling it. i can give you a DL link once finished.

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I’ve compiled 5.7 with the patch, if you want to try it:

Note that I don’t take any responsibility when something breaks. I did not test it myself.

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Thanks so much for the help, really appreciate it, I will give it a try!

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