On Mon, Jul 30, 2018 at 02:34:12PM -0700, Nick Desaulniers wrote:
Starting with Clang-7.0, _THIS_IP_ generates -Wreturn-stack-address warnings for almost every translation unit. In general, I'd prefer to leave this on (returning the address of a stack allocated variable is in general a bad idea) and disable it only at whitelisted call sites.
We can't do something like: #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wreturn-stack-address"
<code> #pragma clang diagnostic pop
in a GNU Statement Expression or macro, hence we use _Pragma, which is its raison d'être: https://gcc.gnu.org/onlinedocs/cpp/Pragmas.html
We also can't use compiler specific pragma's without triggering -Werror=unknown-pragmas in other compilers, so use __diag.
Cc: stable@vger.kernel.org # 4.17, 4.14, 4.9, 4.4 Suggested-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Nick Desaulniers ndesaulniers@google.com
Tested-and-reviewed-by: Nathan Chancellor natechancellor@gmail.com
include/linux/kernel.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 941dc0a5a877..909bb771c0ca 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -168,7 +168,15 @@ #define _RET_IP_ (unsigned long)__builtin_return_address(0) -#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; }) +#define _THIS_IP_ ( \ +{ \
- __label__ __here; \
- __diag_push() \
- __diag_ignore(CLANG, 7, "-Wreturn-stack-address", "") \
+__here: (unsigned long)&&__here; \
- __diag_pop() \
+} \ +) #ifdef CONFIG_LBDAF
# include <asm/div64.h>
2.18.0.345.g5c9ce644c3-goog