diff --git a/glamor/glamor_largepixmap.c b/glamor/glamor_largepixmap.c
index 391f376e9..da3fb6150 100644
--- a/glamor/glamor_largepixmap.c
+++ b/glamor/glamor_largepixmap.c
@@ -1055,6 +1055,15 @@ glamor_composite_largepixmap_region(CARD8 op,
     int source_repeat_type = 0, mask_repeat_type = 0;
     int ok = TRUE;
 
+    if (source_pixmap == dest_pixmap) {
+        glamor_fallback("source and dest pixmaps are the same\n");
+        return FALSE;
+    }
+    if (mask_pixmap == dest_pixmap) {
+        glamor_fallback("mask and dest pixmaps are the same\n");
+        return FALSE;
+    }
+
     if (source->repeat)
         source_repeat_type = source->repeatType;
     else
diff --git a/glamor/glamor_render.c b/glamor/glamor_render.c
index efca36744..05eee913e 100644
--- a/glamor/glamor_render.c
+++ b/glamor/glamor_render.c
@@ -1481,7 +1481,14 @@ glamor_composite_clipped_region(CARD8 op,
         }
     }
 
-    /*XXXXX, self copy? */
+    if (temp_src_pixmap == dest_pixmap) {
+        glamor_fallback("source and dest pixmaps are the same\n");
+        goto out;
+    }
+    if (temp_mask_pixmap == dest_pixmap) {
+        glamor_fallback("mask and dest pixmaps are the same\n");
+        goto out;
+    }
 
     x_dest += dest->pDrawable->x;
     y_dest += dest->pDrawable->y;