kernel stack for linux process

Question

Is the kernel stack for all process shared or there is a seperate kernel stack for each process? If it is seperate for each process where is this stack pointer stored? In task_s

Answer 1

I think each process has its own kernel mode stack. Driver is executing in the kernel mode, the process sometimes will be blocked while executing driver routine. and the operating system can schedule another process to run. The scheduled process can call driver routine again. If kernel stack is shared, 2 processes are using the kernel stack, things will be mixed up. I'm puzzled by this question for a long time. At first I think kernel stack is shared, some books say that. After I read the Linux kernel Development, and see some driver code, I begin to think the kernel stack is not shared.