Why does the kernel use the copy_to_user function?
Couldn’t it just directly operate on data in the user space?
Why does the kernel use the copy_to_user function? Couldn’t it just directly operate on
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Why does the kernel use the copy_to_user function?
Couldn’t it just directly operate on data in the user space?
kernel and user-space applications have different address spaces, so copying to user space require an address space change. Each process has its own (user) address space.
Also, kernel should never crash when copying to user space, so the
copy_to_userfunction probably checks that the destination address is valid (perhaps that address should be paged-in, e.g. from swap space).Read more about linux kernel, syscalls, processes, address space …