Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760446AbcCDXo1 (ORCPT ); Fri, 4 Mar 2016 18:44:27 -0500 Received: from mail-pf0-f180.google.com ([209.85.192.180]:34059 "EHLO mail-pf0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759633AbcCDXo0 (ORCPT ); Fri, 4 Mar 2016 18:44:26 -0500 From: Douglas Anderson To: David Airlie Cc: Mark Yao , Daniel Kurtz , Douglas Anderson , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH] drm: Check for connector->state NULL in drm_atomic_add_affected_connectors Date: Fri, 4 Mar 2016 15:43:53 -0800 Message-Id: <1457135033-11791-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.7.0.rc3.207.g0ac5344 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1984 Lines: 47 On a system I'm doing development on I found a crash. The crawl looked like: PC is at drm_atomic_add_affected_connectors+0x98/0xe8 ... drm_atomic_add_affected_connectors from __drm_atomic_helper_set_config+0x218/0x344 __drm_atomic_helper_set_config from restore_fbdev_mode+0x108/0x250 restore_fbdev_mode from drm_fb_helper_restore_fbdev_mode_unlocked+0x3c/0x80 drm_fb_helper_restore_fbdev_mode_unlocked from rockchip_drm_lastclose+0x1c/0x20 rockchip_drm_lastclose from drm_lastclose+0x4c/0x104 drm_lastclose from drm_release+0x424/0x47c drm_release from __fput+0xf8/0x1d4 __fput from ____fput+0x18/0x1c ____fput from task_work_run+0xa8/0xbc task_work_run from do_exit+0x448/0x91c do_exit from do_group_exit+0x5c/0xcc do_group_exit from get_signal+0x4dc/0x57c get_signal from do_signal+0x9c/0x3b4 do_signal from do_work_pending+0x60/0xb8 do_work_pending from slow_work_pending+0xc/0x20 I found that I could fix the crash by checking connector->state against NULL. This isn't code I'm familiar with and I didn't dig too deep, so I'd appreciate any opinions about whether this is a sane thing to do. Note that I don't actually have graphics up on my system at the moment, so perhaps this is all just a symptom of the strange state I'm in. Signed-off-by: Douglas Anderson --- drivers/gpu/drm/drm_atomic.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index 8fb469c4e4b8..3377d7ddc6d1 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -1147,7 +1147,7 @@ drm_atomic_add_affected_connectors(struct drm_atomic_state *state, * current configuration. */ drm_for_each_connector(connector, state->dev) { - if (connector->state->crtc != crtc) + if (!connector->state || connector->state->crtc != crtc) continue; conn_state = drm_atomic_get_connector_state(state, connector); -- 2.7.0.rc3.207.g0ac5344