问题
I am trying to build a scull device, and have build a .ko file without problem. But when insmoded, then cat of /var/log/kern.log:
May 14 00:33:06 XLM kernel: [ 4251.407594] scull: loading out-of-tree module taints kernel.
May 14 00:33:06 XLM kernel: [ 4251.407680] scull: module verification failed: signature and/or required key missing - tainting kernel
So therefor this error occured bash: /dev/scull: No such device or address (because I have tried to write to /dev/scull0 after mknod /dev/scull 245 0,. But as seen from log, I have not even register the device, because the module is marked as out-of-tree and also no signature.) I do not know why I have signature enabled, when I have disable secure boot in bios. Nevertheless, how can I enable kernel to accept the module in order to use the device? I have MODULE_LICENSE("Dual BSD/GPL"); in source, so the licensing should not be the problem.
来源：https://stackoverflow.com/questions/61798226/how-to-build-external-modules-in-ubuntu