Ask a process question,

Ask a process question-Linux general technology-Linux technology and application information. The following is a detailed description. The user process runs in the user State, and the address space is in the user space,
The system runs in the core State after calling, and the address space is in the kernel space,
Please ask, before and after the system call, that is, the process running in the user space and the kernel space, whether it is the same process or two different processes (kernel processes and user processes ),
If there are two processes, does it have two process descriptors?
If a process is used, is the address space of this user process the sum of user space and kernel space called by the system?
Thank you,