From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764332AbXGWKCi (ORCPT ); Mon, 23 Jul 2007 06:02:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755291AbXGWKCb (ORCPT ); Mon, 23 Jul 2007 06:02:31 -0400 Received: from mail1.sea5.speakeasy.net ([69.17.117.3]:58694 "EHLO mail1.sea5.speakeasy.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753610AbXGWKCa (ORCPT ); Mon, 23 Jul 2007 06:02:30 -0400 Date: Mon, 23 Jul 2007 03:02:29 -0700 (PDT) From: Trent Piepho X-X-Sender: xyzzy@shell2.speakeasy.net To: Adrian Bunk cc: Thierry MERLE , "Dwaine P. Garden" , Mauro Carvalho Chehab , v4l-dvb maintainer list , Linux Kernel Mailing list , Michal Piotrowski Subject: Re: [v4l-dvb-maintainer] [2.6.23 regression fix] usbvision: don't return an uninitialized value In-Reply-To: <20070723080203.GD26212@stusta.de> Message-ID: References: <20070723080203.GD26212@stusta.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 23 Jul 2007, Adrian Bunk wrote: > Commit c5f48367fe54c46805774eeea8e828de54a5ad7b introduced this return > of an uninitialized variable. > > Spotted by the Coverity checker. It spotted that, but it seems it missed the bigger bug, reg->val is unsigned. Since reg->val can't be less than 0, it will never actually return the unitialized variable. This patch should fix it correctly. The vidioc_g_register function was broken too, it wasn't actually setting reg->val to the register value it read. -------------------------------------------------------------------- usbvision: fix bugs in vidioc_[sg]_register functions From: Trent Piepho s_register was assigning the return code to (unsigned)reg->val, rather than errCode, which it what it would return. Except reg->val can't be < 0, so it would never actually return an error. g_register never actually put the value it read into reg->val. Signed-off-by: Trent Piepho diff -r 8e72fe5675b3 -r d5c4fffbbad3 linux/drivers/media/video/usbvision/usbvision-video.c --- a/linux/drivers/media/video/usbvision/usbvision-video.c Sat Jul 21 17:26:40 2007 -0700 +++ b/linux/drivers/media/video/usbvision/usbvision-video.c Mon Jul 23 02:58:31 2007 -0700 @@ -550,6 +550,7 @@ static int vidioc_g_register (struct fil __FUNCTION__, errCode); return errCode; } + reg->val = errCode; return 0; } @@ -564,8 +565,8 @@ static int vidioc_s_register (struct fil if (!v4l2_chip_match_host(reg->match_type, reg->match_chip)) return -EINVAL; /* NT100x has a 8-bit register space */ - reg->val = (u8)usbvision_write_reg(usbvision, reg->reg&0xff, reg->val); - if (reg->val < 0) { + errCode = usbvision_write_reg(usbvision, reg->reg&0xff, reg->val); + if (errCode < 0) { err("%s: VIDIOC_DBG_S_REGISTER failed: error %d", __FUNCTION__, errCode); return errCode;