Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753215AbdGYUTQ (ORCPT ); Tue, 25 Jul 2017 16:19:16 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35080 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753170AbdGYTWR (ORCPT ); Tue, 25 Jul 2017 15:22:17 -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 4.9 113/125] drm/mst: Fix error handling during MST sideband message reception Date: Tue, 25 Jul 2017 12:20:28 -0700 Message-Id: <20170725192020.501400835@linuxfoundation.org> X-Mailer: git-send-email 2.13.3 In-Reply-To: <20170725192014.314851996@linuxfoundation.org> References: <20170725192014.314851996@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 Content-Length: 1486 Lines: 48 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Imre Deak commit 448421b5e93b9177c5698f0cf6f5e72d2995eeca upstream. Handle any error due to partial reads, timeouts etc. to avoid parsing uninitialized data subsequently. Also bail out if the parsing itself fails. 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/20170719114330.26540-2-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_dp_mst_topology.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -2200,11 +2200,17 @@ static void drm_dp_get_one_sb_msg(struct ret = drm_dp_dpcd_read(mgr->aux, basereg + curreply, replyblock, len); if (ret != len) { - DRM_DEBUG_KMS("failed to read a chunk\n"); + DRM_DEBUG_KMS("failed to read a chunk (len %d, ret %d)\n", + len, ret); + return; } + ret = drm_dp_sideband_msg_build(msg, replyblock, len, false); - if (ret == false) + if (!ret) { DRM_DEBUG_KMS("failed to build sideband msg\n"); + return; + } + curreply += len; replylen -= len; }