Comment by soraminazuki
1 day ago
Again, no it's not. Most kernel code doesn't run as PID 0. What you're talking about is the idle task, a very small part of the kernel.
I also did have Linux in mind when writing my comment, but this is basic to how any major general purpose operating system works. Besides, I can't possibly exclude Linux when I say "any modern operating system."
The kernel has many, many threads other than the idle task. Ok, some of them technically have pids other than zero because this is how Linux implements threads. But they all share address space, like threads in any other process. I count, you know, 265 kernel threads on a random Linux system.