diff --git a/randr/rrmode.c b/randr/rrmode.c
index 1117581..302278a 100644
--- a/randr/rrmode.c
+++ b/randr/rrmode.c
@@ -165,7 +165,10 @@ RRModesForScreen (ScreenPtr pScreen, int *num_ret)
     int		num_screen_modes = 0;
 
     screen_modes = xalloc ((num_modes ? num_modes : 1) * sizeof (RRModePtr));
-    
+
+	if (!screen_modes)
+	return NULL;	
+
     /*
      * Add modes from all outputs
      */