[PATCH] i386: Add a temporary to make put_user more type safe
In some code I am developing I had occasion to change the type of a
variable. This made the value put_user was putting to user space wrong.
But the code continued to build cleanly without errors.
Introducing a temporary fixes this problem and at least with gcc-3.3.5 does
not cause gcc any problems with optimizing out the temporary. gcc-4.x
using SSA internally ought to be even better at optimizing out temporaries,
so I don't expect a temporary to become a problem. Especially because in
all correct cases the types on both sides of the assignment to the
temporary are the same.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-i386/uaccess.h b/include/asm-i386/uaccess.h
index 3f1337c..371457b 100644
--- a/include/asm-i386/uaccess.h
+++ b/include/asm-i386/uaccess.h
@@ -197,13 +197,15 @@
#define put_user(x,ptr) \
({ int __ret_pu; \
+ __typeof__(*(ptr)) __pu_val; \
__chk_user_ptr(ptr); \
+ __pu_val = x; \
switch(sizeof(*(ptr))) { \
- case 1: __put_user_1(x, ptr); break; \
- case 2: __put_user_2(x, ptr); break; \
- case 4: __put_user_4(x, ptr); break; \
- case 8: __put_user_8(x, ptr); break; \
- default:__put_user_X(x, ptr); break; \
+ case 1: __put_user_1(__pu_val, ptr); break; \
+ case 2: __put_user_2(__pu_val, ptr); break; \
+ case 4: __put_user_4(__pu_val, ptr); break; \
+ case 8: __put_user_8(__pu_val, ptr); break; \
+ default:__put_user_X(__pu_val, ptr); break; \
} \
__ret_pu; \
})