What userspace is is where you work happens. It has no universal obligation to protect the kernel.
You could possibly say that the point of working in userspace (instead of in kernel space) is to protect the kernel.
In the latter case, sorry. I honestly agree I should have caught that.
In the first case my thought process goes as follows (hoping someone knowledgeable will correct me):
- user space may very well contain hostile processes (trojans, rootkits, - even intentionally in the case where a user inspects malware in some kind of container or chroot environment.
- user space may contain mechanisms that attempts to protect the kernel, but a typical kernel (linux, and I guess most other free kernels) cannot rely on it.
- I tried searching for userspace protect kernel and the closest thing I found was the act of separating userspace from kernel space protects the kernel which is what I tried to point out in my post above.