On Tue, Jan 13, 2015 at 02:41:20PM -0500, Chris Metcalf wrote:
> Add an extra intermediate variable to __get_user and __put_user
> to give sparse an opportunity to detect mismatches.
>
> Signed-off-by: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Reviewed-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> arch/tile/include/asm/uaccess.h | 19 +++++++++++--------
> 1 file changed, 11 insertions(+), 8 deletions(-)
>
> diff --git a/arch/tile/include/asm/uaccess.h b/arch/tile/include/asm/uaccess.h
> index b81b24a8489b..f41cb53cf645 100644
> --- a/arch/tile/include/asm/uaccess.h
> +++ b/arch/tile/include/asm/uaccess.h
> @@ -210,14 +210,16 @@ extern int __get_user_bad(void)
> #define __get_user(x, ptr) \
> ({ \
> int __ret; \
> + typeof(x) _x; \
> __chk_user_ptr(ptr); \
> switch (sizeof(*(ptr))) { \
> - case 1: __get_user_1(x, ptr, __ret); break; \
> - case 2: __get_user_2(x, ptr, __ret); break; \
> - case 4: __get_user_4(x, ptr, __ret); break; \
> - case 8: __get_user_8(x, ptr, __ret); break; \
> + case 1: __get_user_1(_x, ptr, __ret); break; \
> + case 2: __get_user_2(_x, ptr, __ret); break; \
> + case 4: __get_user_4(_x, ptr, __ret); break; \
> + case 8: __get_user_8(_x, ptr, __ret); break; \
> default: __ret = __get_user_bad(); break; \
> } \
> + (x) = (typeof(*(ptr))) _x; \
> __ret; \
> })
>
> @@ -289,12 +291,13 @@ extern int __put_user_bad(void)
> #define __put_user(x, ptr) \
> ({ \
> int __ret; \
> + typeof(*(ptr)) _x = (x); \
> __chk_user_ptr(ptr); \
> switch (sizeof(*(ptr))) { \
> - case 1: __put_user_1(x, ptr, __ret); break; \
> - case 2: __put_user_2(x, ptr, __ret); break; \
> - case 4: __put_user_4(x, ptr, __ret); break; \
> - case 8: __put_user_8(x, ptr, __ret); break; \
> + case 1: __put_user_1(_x, ptr, __ret); break; \
> + case 2: __put_user_2(_x, ptr, __ret); break; \
> + case 4: __put_user_4(_x, ptr, __ret); break; \
> + case 8: __put_user_8(_x, ptr, __ret); break; \
> default: __ret = __put_user_bad(); break; \
> } \
> __ret; \
> --
> 2.1.2
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