Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751179AbbGARM5 (ORCPT ); Wed, 1 Jul 2015 13:12:57 -0400 Received: from mail-vn0-f42.google.com ([209.85.216.42]:41976 "EHLO mail-vn0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750832AbbGARMt (ORCPT ); Wed, 1 Jul 2015 13:12:49 -0400 MIME-Version: 1.0 In-Reply-To: References: <1435769495-2025-1-git-send-email-colin.king@canonical.com> Date: Wed, 1 Jul 2015 18:12:48 +0100 Message-ID: Subject: Re: [PATCH] drm/nouveau: usif_ioctl: ensure returns are initialized From: Emil Velikov To: Ilia Mirkin Cc: Colin King , Ben Skeggs , "dri-devel@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2468 Lines: 49 On 1 July 2015 at 17:56, Ilia Mirkin wrote: > On Wed, Jul 1, 2015 at 12:51 PM, Colin King wrote: >> From: Colin Ian King >> >> Various usif_ioctl helper functions do not initialize the >> return variable ret and some of the error handling return >> paths just return garbage values that were on the stack (or >> in a register). I believe that in all the cases, the >> initial ret variable should be set to -EINVAL and subsequent >> paths through these helper functions set it appropriately >> otherwise. >> >> Found via static analysis using cppcheck: >> >> [drivers/gpu/drm/nouveau/nouveau_usif.c:138]: >> (error) Uninitialized variable: ret > > It sure would seem that way, wouldn't it? > > #define nvif_unpack(d,vl,vh,m) ({ \ > if ((vl) == 0 || ret == -ENOSYS) { \ > int _size = sizeof(d); \ > if (_size <= size && (d).version >= (vl) && \ > (d).version <= (vh)) { \ > data = (u8 *)data + _size; \ > size = size - _size; \ > ret = ((m) || !size) ? 0 : -E2BIG; \ > } else { \ > ret = -ENOSYS; \ > } \ > } \ > (ret == 0); \ > }) > > So actually it does get initialized, and I guess cppcheck doesn't know > about macros? > I think I'm having deja-vu, but I do recall a similar mention to Ben. Although in my defence I've assumed that nvif_unpack was a function, as macros normally are normally all caps. Seems like the patch that capitalises nvif_unpack never made it upstream :'-( Cheers, Emil -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/