From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [PATCH] compiler: Correct macro parameter expansion problem Date: Mon, 3 Nov 2014 06:34:13 -0800 Message-ID: <1415025253-15976-1-git-send-email-jeffrey.t.kirsher@intel.com> Return-path: Received: from mga03.intel.com ([134.134.136.65]:25688 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751991AbaKCOeR (ORCPT ); Mon, 3 Nov 2014 09:34:17 -0500 Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: sparse@chrisli.org Cc: Mark Rustad , linux-kernel@vger.kernel.org, linux-sparse@vger.kernel.org, Jeff Kirsher From: Mark Rustad The macro __compiletime_error_fallback has an error in that it lacks parens around the expansion of an expression. It also lacks a conversion to a boolean value. The first problem can result in a mis-evaluation. The second problem can also result in an error if the value comes out negative. That would thwart the intended error generation. That is, the error being asserted would not in fact generate an error. Fix both problems by adding !!() to the expansion. Signed-off-by: Mark Rustad Tested-by: Aaron Brown Signed-off-by: Jeff Kirsher --- include/linux/compiler.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index d5ad7b1..59dc611 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -331,7 +331,7 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect); */ # ifndef __CHECKER__ # define __compiletime_error_fallback(condition) \ - do { ((void)sizeof(char[1 - 2 * condition])); } while (0) + do { ((void)sizeof(char[1 - 2 * !!(condition)])); } while (0) # endif #endif #ifndef __compiletime_error_fallback -- 1.9.3