From 4b19bec97c882da09f7fd600895e0df1534a58dc Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 15 Jun 2020 12:06:11 -0700 Subject: [PATCH] docs: deprecated.rst: Add uninitialized_var() Nothing should be using this macro, and the entire idea of tricking the compiler into silencing such warnings is a mistake. Cc: Jonathan Corbet Cc: "Gustavo A. R. Silva" Cc: Joe Perches Cc: linux-doc@vger.kernel.org Reviewed-by: Nick Desaulniers Signed-off-by: Kees Cook --- Documentation/process/deprecated.rst | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/Documentation/process/deprecated.rst b/Documentation/process/deprecated.rst index 652e2aa02a66..943a926ecbbb 100644 --- a/Documentation/process/deprecated.rst +++ b/Documentation/process/deprecated.rst @@ -51,6 +51,24 @@ to make sure their systems do not continue running in the face of "unreachable" conditions. (For example, see commits like `this one `_.) +uninitialized_var() +------------------- +For any compiler warnings about uninitialized variables, just add +an initializer. Using the uninitialized_var() macro (or similar +warning-silencing tricks) is dangerous as it papers over `real bugs +`_ +(or can in the future), and suppresses unrelated compiler warnings +(e.g. "unused variable"). If the compiler thinks it is uninitialized, +either simply initialize the variable or make compiler changes. Keep in +mind that in most cases, if an initialization is obviously redundant, +the compiler's dead-store elimination pass will make sure there are no +needless variable writes. + +As Linus has said, this macro +`must `_ +`be `_ +`removed `_. + open-coded arithmetic in allocator arguments -------------------------------------------- Dynamic size calculations (especially multiplication) should not be -- 2.11.0