[Intel-gfx] [PATCH 4.9 52/66] drm/i915: Check for NULL atomic state in intel_crtc_disable_noatomic()

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>

commit 6d1d427a4e24c403b4adf928d61994bdaa0ca03a upstream.

In intel_crtc_disable_noatomic(), bail on a failure to allocate an
atomic state to avoid a NULL pointer dereference.

Fixes: 4a80655827af ("drm/i915: Pass atomic state to crtc enable/disable functions")
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Daniel Vetter <daniel.vetter at intel.com>
Cc: Jani Nikula <jani.nikula at linux.intel.com>
Cc: intel-gfx at lists.freedesktop.org
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1484922525-6131-4-git-send-email-ander.conselvan.de.oliveira@intel.com
(cherry picked from commit 31bb2ef97ea9db343348f9b5ccaa9bb6f48fc655)
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>

---
 drivers/gpu/drm/i915/intel_display.c |    6 ++++++
 1 file changed, 6 insertions(+)

--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6869,6 +6869,12 @@ static void intel_crtc_disable_noatomic(
 	}
 
 	state = drm_atomic_state_alloc(crtc->dev);
+	if (!state) {
+		DRM_DEBUG_KMS("failed to disable [CRTC:%d:%s], out of memory",
+			      crtc->base.id, crtc->name);
+		return;
+	}
+
 	state->acquire_ctx = crtc->dev->mode_config.acquire_ctx;
 
 	/* Everything's already locked, -EDEADLK can't happen. */