diff --git a/drivers/gpu/drm/i915/i915_active.c b/drivers/gpu/drm/i915/i915_active.c
index 584b247df9bce..13f304a29fc83 100644
--- a/drivers/gpu/drm/i915/i915_active.c
+++ b/drivers/gpu/drm/i915/i915_active.c
@@ -268,6 +268,8 @@ int i915_active_wait(struct i915_active *ref)
 	int err;
 
 	might_sleep();
+	might_lock(&ref->mutex);
+
 	if (RB_EMPTY_ROOT(&ref->tree))
 		return 0;