Messages in this thread | | | Subject | Re: Why system call need to copy the date from the userspace before using it | From | Catalin Marinas <> | Date | Wed, 13 Apr 2005 12:10:46 +0100 |
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Tomko <tomko@haha.com> 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).
-- Catalin
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