Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753053AbbGAQ4t (ORCPT ); Wed, 1 Jul 2015 12:56:49 -0400 Received: from mail-oi0-f49.google.com ([209.85.218.49]:36463 "EHLO mail-oi0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750793AbbGAQ4i (ORCPT ); Wed, 1 Jul 2015 12:56:38 -0400 MIME-Version: 1.0 In-Reply-To: <1435769495-2025-1-git-send-email-colin.king@canonical.com> References: <1435769495-2025-1-git-send-email-colin.king@canonical.com> Date: Wed, 1 Jul 2015 12:56:37 -0400 X-Google-Sender-Auth: Z8pDUQO-XLq5BJOL4llRK3HqiZM Message-ID: Subject: Re: [PATCH] drm/nouveau: usif_ioctl: ensure returns are initialized From: Ilia Mirkin To: Colin King Cc: David Airlie , 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: 5076 Lines: 114 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? > [drivers/gpu/drm/nouveau/nouveau_usif.c:179]: > (error) Uninitialized variable: ret > [drivers/gpu/drm/nouveau/nouveau_usif.c:202]: > (error) Uninitialized variable: ret > [drivers/gpu/drm/nouveau/nouveau_usif.c:241]: > (error) Uninitialized variable: ret > [drivers/gpu/drm/nouveau/nouveau_usif.c:157]: > (error) Uninitialized variable: ret > [drivers/gpu/drm/nouveau/nouveau_usif.c:288]: > (error) Uninitialized variable: ret > > Signed-off-by: Colin Ian King > --- > drivers/gpu/drm/nouveau/nouveau_usif.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_usif.c b/drivers/gpu/drm/nouveau/nouveau_usif.c > index cb1182d..01b50a2 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_usif.c > +++ b/drivers/gpu/drm/nouveau/nouveau_usif.c > @@ -129,7 +129,7 @@ usif_notify_new(struct drm_file *f, void *data, u32 size, void *argv, u32 argc) > struct nvif_notify_req_v0 v0; > } *req; > struct usif_notify *ntfy; > - int ret; > + int ret = -EINVAL; > > if (nvif_unpack(args->v0, 0, 0, true)) { > if (usif_notify_find(f, args->v0.index)) > @@ -170,7 +170,7 @@ usif_notify_del(struct drm_file *f, void *data, u32 size, void *argv, u32 argc) > struct nvif_ioctl_ntfy_del_v0 v0; > } *args = data; > struct usif_notify *ntfy; > - int ret; > + int ret = -EINVAL; > > if (nvif_unpack(args->v0, 0, 0, true)) { > if (!(ntfy = usif_notify_find(f, args->v0.index))) > @@ -193,7 +193,7 @@ usif_notify_get(struct drm_file *f, void *data, u32 size, void *argv, u32 argc) > struct nvif_ioctl_ntfy_del_v0 v0; > } *args = data; > struct usif_notify *ntfy; > - int ret; > + int ret = -EINVAL; > > if (nvif_unpack(args->v0, 0, 0, true)) { > if (!(ntfy = usif_notify_find(f, args->v0.index))) > @@ -232,7 +232,7 @@ usif_notify_put(struct drm_file *f, void *data, u32 size, void *argv, u32 argc) > struct nvif_ioctl_ntfy_put_v0 v0; > } *args = data; > struct usif_notify *ntfy; > - int ret; > + int ret = -EINVAL; > > if (nvif_unpack(args->v0, 0, 0, true)) { > if (!(ntfy = usif_notify_find(f, args->v0.index))) > @@ -269,7 +269,7 @@ usif_object_new(struct drm_file *f, void *data, u32 size, void *argv, u32 argc) > struct nvif_ioctl_new_v0 v0; > } *args = data; > struct usif_object *object; > - int ret; > + int ret = -EINVAL; > > if (!(object = kmalloc(sizeof(*object), GFP_KERNEL))) > return -ENOMEM; > -- > 2.1.4 > > -- > 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/ -- 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/