From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754134Ab0H0F5u (ORCPT ); Fri, 27 Aug 2010 01:57:50 -0400 Received: from mgw2.diku.dk ([130.225.96.92]:59068 "EHLO mgw2.diku.dk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752284Ab0H0F5n (ORCPT ); Fri, 27 Aug 2010 01:57:43 -0400 From: Julia Lawall To: Mauro Carvalho Chehab Cc: kernel-janitors@vger.kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] drivers/media/video/em28xx: Remove potential NULL dereference Date: Fri, 27 Aug 2010 07:57:18 +0200 Message-Id: <1282888640-27042-2-git-send-email-julia@diku.dk> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1282888640-27042-1-git-send-email-julia@diku.dk> References: <1282888640-27042-1-git-send-email-julia@diku.dk> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If the NULL test is necessary, the initialization involving a dereference of the tested value should be moved after the NULL test. The sematic patch that fixes this problem is as follows: (http://coccinelle.lip6.fr/) // @@ type T; expression E; identifier i,fld; statement S; @@ - T i = E->fld; + T i; ... when != E when != i if (E == NULL) S + i = E->fld; // Signed-off-by: Julia Lawall --- drivers/media/video/em28xx/em28xx-video.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c index 7b9ec6e..95a4b60 100644 --- a/drivers/media/video/em28xx/em28xx-video.c +++ b/drivers/media/video/em28xx/em28xx-video.c @@ -277,12 +277,13 @@ static void em28xx_copy_vbi(struct em28xx *dev, { void *startwrite, *startread; int offset; - int bytesperline = dev->vbi_width; + int bytesperline; if (dev == NULL) { em28xx_isocdbg("dev is null\n"); return; } + bytesperline = dev->vbi_width; if (dma_q == NULL) { em28xx_isocdbg("dma_q is null\n");