| From cpaul@redhat.com Sat Jun 4 13:44:11 2016 |
| From: Lyude <cpaul@redhat.com> |
| Date: Tue, 31 May 2016 12:49:07 -0400 |
| Subject: drm/atomic: Verify connector->funcs != NULL when clearing states |
| To: stable@vger.kernel.org, Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Cc: Lyude <cpaul@redhat.com>, David Airlie <airlied@linux.ie>, dri-devel@lists.freedesktop.org (open list:DRM DRIVERS), linux-kernel@vger.kernel.org (open list) |
| Message-ID: <1464713347-28982-5-git-send-email-cpaul@redhat.com> |
| |
| From: Lyude <cpaul@redhat.com> |
| |
| 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 <daniel.vetter@ffwll.ch> |
| Signed-off-by: Lyude <cpaul@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| drivers/gpu/drm/drm_atomic.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/drivers/gpu/drm/drm_atomic.c |
| +++ b/drivers/gpu/drm/drm_atomic.c |
| @@ -139,7 +139,7 @@ void drm_atomic_state_default_clear(stru |
| for (i = 0; i < state->num_connector; i++) { |
| struct drm_connector *connector = state->connectors[i]; |
| |
| - if (!connector) |
| + if (!connector || !connector->funcs) |
| continue; |
| |
| /* |
