Am Mittwoch, den 24.02.2021, 16:21 +0100 schrieb Bruno Thomsen:

Hi,

No, this is not a regression from 5.10. It seems that many attempts to
fix cdc-acm in the 5.x kernel series have failed to fix the root cause of
these oops. I have not seen this on 4.14 and 4.19, but I have observed
it on at least 5.3 and newer kernels in slight variations.
I guess this is because cdc-acm is very common in the embedded
ARM world and rarely used on servers or laptops. Combined with
ARM devices still commonly use 4.x LTS kernels. Not sure if
hardening options on the kernel has increased change of reproducing
oops.

OK, so this is not an additional problem.
According to your logs, an URB that should have been killed wasn't.

I am ready to test new patches and will continue to report oops

Could you test the attached patches?

	Regards
		Oliver