From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934140AbZGQG3m (ORCPT ); Fri, 17 Jul 2009 02:29:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934122AbZGQG3m (ORCPT ); Fri, 17 Jul 2009 02:29:42 -0400 Received: from hera.kernel.org ([140.211.167.34]:45468 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934116AbZGQG3l (ORCPT ); Fri, 17 Jul 2009 02:29:41 -0400 Message-ID: <4A601AC5.1010308@kernel.org> Date: Fri, 17 Jul 2009 15:31:33 +0900 From: Tejun Heo User-Agent: Thunderbird 2.0.0.22 (X11/20090605) MIME-Version: 1.0 To: Julia Lawall CC: linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: Re: [PATCH 1/4] drivers/block: adjust NULL test References: In-Reply-To: X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 17 Jul 2009 06:29:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Julia Lawall wrote: > From: Julia Lawall > > dtp is derefenced on the lines above the test !dtp, and so it cannot be > NULL at this point. > > A simplified version of the semantic match that finds this problem is as > follows: (http://www.emn.fr/x-info/coccinelle/) > > // > @r@ > expression x,E,E1; > identifier f,l; > position p1,p2; > @@ > > *x@p1->f = E1; > ... when != x = E > when != goto l; > ( > *x@p2 == NULL > | > *x@p2 != NULL > ) > // > > Signed-off-by: Julia Lawall Indeed, added to my temp block tree. Will forward upstream in a few days. Thanks. -- tejun