In linux, the “process descriptor” is struct task_struct [and some others]. These are stored in kernel address space [above PAGE_OFFSET ] and not in userspace. This is more relevant to 32 bit kernels where PAGE_OFFSET is set to 0xc0000000. Also, the kernel has a single address space mapping of its own.

Where is process located in Linux?

On Linux, the symlink /proc/<pid>/exe has the path of the executable. Use the command readlink -f /proc/<pid>/exe to get the value.

Where is process table stored?

The process table in Linux (such as in nearly every other operating system) is simply a data structure in the RAM of a computer. It holds information about the processes that are currently handled by the OS.