Won't be the same instruction. It'll be waiting for a hardware interrupt without properly preparing to handle signals at the same time because someone assumed it was fast. Kernel code isn't held together with any less duct tape than user code, although we hope it crashes less.

In Linux, any thread running in the kernel is unkillable unless that section of kernel code made arrangements to be killable. When kernel code blocks, you can get unkillable processes. They show as D state (uninterruptible wait).