From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-10.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5E950C07E9A for ; Mon, 12 Jul 2021 21:59:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 42838601FC for ; Mon, 12 Jul 2021 21:59:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230457AbhGLWCa (ORCPT ); Mon, 12 Jul 2021 18:02:30 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:46772 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229818AbhGLWC2 (ORCPT ); Mon, 12 Jul 2021 18:02:28 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 6ED781C0B7A; Mon, 12 Jul 2021 23:59:38 +0200 (CEST) Date: Mon, 12 Jul 2021 23:59:37 +0200 From: Pavel Machek To: Sasha Levin Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Xie Yongji , Gerd Hoffmann , dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org Subject: Re: [PATCH AUTOSEL 4.4 08/31] drm/virtio: Fixes a potential NULL pointer dereference on probe failure Message-ID: <20210712215937.GA9488@amd> References: <20210706112931.2066397-1-sashal@kernel.org> <20210706112931.2066397-8-sashal@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="bg08WKrSYDhXBjb5" Content-Disposition: inline In-Reply-To: <20210706112931.2066397-8-sashal@kernel.org> User-Agent: Mutt/1.5.23 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --bg08WKrSYDhXBjb5 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > From: Xie Yongji >=20 > [ Upstream commit 17f46f488a5d82c5568e6e786cd760bba1c2ee09 ] >=20 > The dev->dev_private might not be allocated if virtio_gpu_pci_quirk() > or virtio_gpu_init() failed. In this case, we should avoid the cleanup > in virtio_gpu_release(). The check is in wrong place at least in 4.4: > +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c > @@ -257,6 +257,9 @@ int virtio_gpu_driver_unload(struct drm_device *dev) > flush_work(&vgdev->config_changed_work); > vgdev->vdev->config->del_vqs(vgdev->vdev); > =20 > + if (!vgdev) > + return; > + Pointer is dereferenced before being tested. Best regards, Pavel -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany --bg08WKrSYDhXBjb5 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAmDsu0kACgkQMOfwapXb+vJjkQCfTnZfEObWPQ0KW+EVB/gjNplI MTsAoLIl0zT4dRziH65vFg9CK41DHEHK =xObD -----END PGP SIGNATURE----- --bg08WKrSYDhXBjb5--