From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Lyude To: stable@vger.kernel.org, Greg Kroah-Hartman Cc: Lyude , David Airlie , dri-devel@lists.freedesktop.org (open list:DRM DRIVERS), linux-kernel@vger.kernel.org (open list) Subject: [PATCH 4/4] drm/atomic: Verify connector->funcs != NULL when clearing states Date: Tue, 31 May 2016 12:49:07 -0400 Message-Id: <1464713347-28982-5-git-send-email-cpaul@redhat.com> In-Reply-To: <1464713347-28982-1-git-send-email-cpaul@redhat.com> References: <1464713347-28982-1-git-send-email-cpaul@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Unfortunately since we don't have Dave's connector refcounting patch here yet, it's very possible that drm_atomic_state_default_clear() could get called by intel_display_resume() when intel_dp_mst_destroy_connector() isn't completely finished destroying an mst connector, but has already finished setting connector->funcs to NULL. As such, we need to treat the connector like it's already been destroyed and just skip it, otherwise we'll end up dereferencing a NULL pointer. This fix is only required for 4.6 and below. David Airlie's patchseries for 4.7 to add connector reference counting provides a more proper fix for this. Changes since v1: - Fix leftover whitespace Upstream fix: 0552f7651bc2 ("drm/i915/mst: use reference counted connectors. (v3)") Reviewed-by: Daniel Vetter Signed-off-by: Lyude --- 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 8ee1db8..d307d96 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -139,7 +139,7 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state) for (i = 0; i < state->num_connector; i++) { struct drm_connector *connector = state->connectors[i]; - if (!connector) + if (!connector || !connector->funcs) continue; /* -- 2.5.5