From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933787AbeBMIo2 (ORCPT ); Tue, 13 Feb 2018 03:44:28 -0500 Received: from mail-lf0-f67.google.com ([209.85.215.67]:44094 "EHLO mail-lf0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933631AbeBMIo0 (ORCPT ); Tue, 13 Feb 2018 03:44:26 -0500 X-Google-Smtp-Source: AH8x225wb2P8/HL/KCYHJ3sMREEWHGOBWAtdjeerk3guh/ZtDfIH04yFtUwlHXvgyTRleMGXMKdQ0Q== From: Oleksandr Andrushchenko To: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: daniel.vetter@intel.com, gustavo@padovan.org, airlied@linux.ie, seanpaul@chromium.org, Oleksandr Andrushchenko Subject: [PATCH] drm/simple_kms_helper: Fix NULL pointer dereference with no active CRTC Date: Tue, 13 Feb 2018 10:44:16 +0200 Message-Id: <1518511456-28257-1-git-send-email-andr2000@gmail.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Oleksandr Andrushchenko It is possible that drm_simple_kms_plane_atomic_check called with no CRTC set, e.g. when user-space application sets CRTC_ID/FB_ID to 0 before doing any actual drawing. This leads to NULL pointer dereference because in this case new CRTC state is NULL and must be checked before accessing. Signed-off-by: Oleksandr Andrushchenko --- drivers/gpu/drm/drm_simple_kms_helper.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_simple_kms_helper.c b/drivers/gpu/drm/drm_simple_kms_helper.c index 9ca8a4a59b74..a05eca9cec8b 100644 --- a/drivers/gpu/drm/drm_simple_kms_helper.c +++ b/drivers/gpu/drm/drm_simple_kms_helper.c @@ -121,8 +121,10 @@ static int drm_simple_kms_plane_atomic_check(struct drm_plane *plane, pipe = container_of(plane, struct drm_simple_display_pipe, plane); crtc_state = drm_atomic_get_new_crtc_state(plane_state->state, &pipe->crtc); - if (!crtc_state->enable) - return 0; /* nothing to check when disabling or disabled */ + + if (!crtc_state || !crtc_state->enable) + /* nothing to check when disabling or disabled or no CRTC set */ + return 0; if (crtc_state->enable) drm_mode_get_hv_timing(&crtc_state->mode, -- 2.7.4