From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753933AbYKZPs0 (ORCPT ); Wed, 26 Nov 2008 10:48:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751280AbYKZPsQ (ORCPT ); Wed, 26 Nov 2008 10:48:16 -0500 Received: from gw-ca.panasas.com ([66.104.249.162]:22689 "EHLO laguna.int.panasas.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751128AbYKZPsP (ORCPT ); Wed, 26 Nov 2008 10:48:15 -0500 Message-ID: <492D6FB8.80401@panasas.com> Date: Wed, 26 Nov 2008 17:48:08 +0200 From: Benny Halevy User-Agent: Thunderbird 3.0a1 (X11/2008050714) MIME-Version: 1.0 To: Andrew Morton CC: lkml Subject: WARN_ON out of range error in ERR_PTR? Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 26 Nov 2008 15:46:36.0906 (UTC) FILETIME=[2A6054A0:01C94FDE] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andrew, After hitting a bug where an nfs error -10021 wasn't handled correctly since IS_ERR returned false on its ERR_PTR value I realized that adding a BUG_ON to make sure the mapped error is in the valid range would have caught this. Since ERR_PTR is not called on the critical path (unlike IS_ERR) but rather on the error handling path I believe we can tolerate the extra cost. The reason this is just a WARN_ON and not BUG_ON is to make fixing it easier, although I do consider calling ERR_PTR on an out of range error a pretty dangerous bug as the error might go unnoticed. How about committing the following patch to -mm? Signed-off-by: Benny Halevy --- include/linux/err.h | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/include/linux/err.h b/include/linux/err.h index ec87f31..81df84f 100644 --- a/include/linux/err.h +++ b/include/linux/err.h @@ -2,7 +2,7 @@ #define _LINUX_ERR_H #include - +#include #include /* @@ -21,6 +21,7 @@ static inline void *ERR_PTR(long error) { + WARN_ON(error && !IS_ERR_VALUE(error)); return (void *) error; } -- 1.6.0.2