I should say that I’ve been running 455.46.01 and 455.46.02 drivers with the patch from 455.23.04: Page allocation failure in kernel module at random points - #55 by aplattner for a couple weeks and have not seen this bug occur. I cannot be sure, but it is possible that this bug is related to the one in that other thread, and may be fixed indirectly by that patch. For example, where nvkms_alloc would previously return NULL and crash on dereference, it no longer returns NULL and doesn’t crash.
If anyone has relatively frequent occurrences of this bug, please try the patch from that other thread and report if it helps or not.
PS: If it doesn’t crash then it doesn’t mean the NULL pointer bug is fixed. There is still somewhere a NULL pointer check missing.