From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753787AbdGYTf3 (ORCPT ); Tue, 25 Jul 2017 15:35:29 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36738 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754122AbdGYTZV (ORCPT ); Tue, 25 Jul 2017 15:25:21 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dave Airlie , Lyude , Daniel Vetter , Imre Deak Subject: [PATCH 4.12 169/196] drm/mst: Avoid dereferencing a NULL mstb in drm_dp_mst_handle_up_req() Date: Tue, 25 Jul 2017 12:22:48 -0700 Message-Id: <20170725192054.414248136@linuxfoundation.org> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170725192046.422343510@linuxfoundation.org> References: <20170725192046.422343510@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Imre Deak commit 7f8b3987da54cb4d41ad2545cd4d7958b9a36bdf upstream. In case of an unknown broadcast message is sent mstb will remain unset, so check for this. Cc: Dave Airlie Cc: Lyude Cc: Daniel Vetter Signed-off-by: Imre Deak Reviewed-by: Lyude Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20170719114330.26540-3-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_dp_mst_topology.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2324,7 +2324,9 @@ static int drm_dp_mst_handle_up_req(stru DRM_DEBUG_KMS("Got RSN: pn: %d avail_pbn %d\n", msg.u.resource_stat.port_number, msg.u.resource_stat.available_pbn); } - drm_dp_put_mst_branch_device(mstb); + if (mstb) + drm_dp_put_mst_branch_device(mstb); + memset(&mgr->up_req_recv, 0, sizeof(struct drm_dp_sideband_msg_rx)); } return ret;