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Commit 20aa7b21 authored by Andrew Morton's avatar Andrew Morton Committed by Linus Torvalds
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[PATCH] probe_kernel_address() needs to do set_fs() 



probe_kernel_address() purports to be generic, only it forgot to select
KERNEL_DS, so it presently won't work right on all architectures.

Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c140e110

include/linux/uaccess.h

+8 −0
Original line number Diff line number Diff line
@@ -65,14 +65,22 @@ static inline unsigned long __copy_from_user_nocache(void *to, 
 * do_page_fault() doesn't attempt to take mmap_sem.  This makes

 * probe_kernel_address() suitable for use within regions where the caller

 * already holds mmap_sem, or other locks which nest inside mmap_sem.

 * This must be a macro because __get_user() needs to know the types of the

 * args.

 *

 * We don't include enough header files to be able to do the set_fs().  We

 * require that the probe_kernel_address() caller will do that.

 */

#define probe_kernel_address(addr, retval)		\

	({						\

		long ret;				\

		mm_segment_t old_fs = get_fs();		\

							\

		set_fs(KERNEL_DS);			\

		pagefault_disable();			\

		ret = __get_user(retval, addr);		\

		pagefault_enable();			\

		set_fs(old_fs);				\

		ret;					\

	})