2 files changed, 10 insertions, 5 deletions

diff --git a/arch/alpha/include/asm/uaccess.h b/arch/alpha/include/asm/uaccess.h
index e69c4e13c328..cf4ac791a592 100644
--- a/arch/alpha/include/asm/uaccess.h
+++ b/arch/alpha/include/asm/uaccess.h
@@ -30,11 +30,13 @@
  * Address valid if:
  *  - "addr" doesn't have any high-bits set
  *  - AND "size" doesn't have any high-bits set
- *  - AND "addr+size" doesn't have any high-bits set
+ *  - AND "addr+size-(size != 0)" doesn't have any high-bits set
  *  - OR we are in kernel mode.
  */
-#define __access_ok(addr, size) \
-        ((get_fs().seg & (addr | size | (addr+size))) == 0)
+#define __access_ok(addr, size) ({                              \
+        unsigned long __ao_a = (addr), __ao_b = (size);         \
+        unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b;    \
+        (get_fs().seg & (__ao_a | __ao_b | __ao_end)) == 0; })
 
 #define access_ok(addr, size)                           \
 ({                                                      \
diff --git a/arch/sh/include/asm/uaccess.h b/arch/sh/include/asm/uaccess.h
index deebbfab5342..5fe751ad7582 100644
--- a/arch/sh/include/asm/uaccess.h
+++ b/arch/sh/include/asm/uaccess.h
@@ -16,8 +16,11 @@
  * sum := addr + size;  carry? --> flag = true;
  * if (sum >= addr_limit) flag = true;
  */
-#define __access_ok(addr, size)         \
-        (__addr_ok((addr) + (size)))
+#define __access_ok(addr, size) ({                              \
+        unsigned long __ao_a = (addr), __ao_b = (size);         \
+        unsigned long __ao_end = __ao_a + __ao_b - !!__ao_b;    \
+        __ao_end >= __ao_a && __addr_ok(__ao_end); })
+
 #define access_ok(addr, size)   \
         (__chk_user_ptr(addr),          \
          __access_ok((unsigned long __force)(addr), (size)))