drm/i915: Check for NULL atomic state in intel_crtc_disable_noatomic()

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@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: intel-gfx@lists.freedesktop.org
Cc: <stable@vger.kernel.org> # v4.9+
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@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@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 7a9040fc6e5ab6b45462de73fbd1ff9f91b769ed..f6dd073afdc9abe8638434931bb76072e41683d2 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -6850,6 +6850,12 @@ static void intel_crtc_disable_noatomic(struct drm_crtc *crtc)
        }
 
        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. */