Re: Why system call need to copy the date from the userspace before using it

Catalin Marinas wrote:

Tomko <[email protected]> wrote:

Inside the system call , the kernel often copy the data by calling
copy_from_user() rather than just using strcpy(), is it because the
memory mapping in kenel space is different from user space?

No, it is because this function checks whether the access to the user
space address is OK. There are situations when it can also sleep (page
not present).

what u means "OK"? kernel space should have right to access any memory address , can u expained in details what u means "OK"?

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