On Tue, May 09, 2017 at 08:45:22AM +0200, Ingo Molnar wrote: > We only have ~115 code blocks in the kernel that set/restore KERNEL_DS, it > would > be a pity to add a runtime check to every system call ...
I think we should simply strive to remove all of them that aren't in core scheduler / arch code. Basically evetyytime we do the oldfs = get_fs(); set_fs(KERNEL_DS); .. set_fs(oldfs); trick we're doing something wrong, and there should always be better ways to archive it. E.g. using iov_iter with a ITER_KVEC type consistently would already remove most of them.