Comment # 15 on bug 1177973 from Bernhard Randolf

(In reply to Takashi Iwai from comment #14)
> Could you check which package does xcmddc belong to?
>   % rpm -qf $(which xcmddc)

xcm-0.5.4-lp152.3.5.x86_64    (I'm back on Leap 15.2 today, using your kernel,
but change back to tumbleweed easily if required)

> Also, if possible, identify who uses it.  This can be udev.

How would I do that?
I tried

    % rpm -q --whatrequires xcm
    no package requires xcm

So I did

    % zypper rm xcm 

which did not uninstall anything else (as expected).

Reboot succeeded, I did not yet notice anything that did not work as before
removing xcm.
See dmesg_attempt3_5.9.1-1.gc31670b-default.out which I will upload in a
minute.

Out of curiosity, I tried to reboot with kernel-default-5.9.0-2.1 which was not
yet purged (installed from Kernel:Head last Saturday).
This one now also boots without trouble (only tried twice, so far, so this
might need further investigation)
See dmesg_attempt4_5.9.0-2.gb1f22f7-default.out which will follow asap.

So eventually xcmddc might be the culprit in this case.
No idea why this is installed on my system, I can not recall I ever installed
that manually (which does not mean anything, I don't remember a lot of things I
eventually did, people say...)

I'll do some more reboots with this 5.9.0 kernel and see if I can reproduce the
kernel-panic once again in the mean time...