From http://www.jwz.org/xscreensaver/xscreensaver-5.33.tar.gz

[xscreensaver] / hacks / celtic.c

diff --git a/hacks/celtic.c b/hacks/celtic.c
index 103b64718b03814e698f2b0fb0cf1c35e476e707..6ce4e7074dadb899a8a2e9e749d11c1c33d1bd72 100644 (file)
--- a/hacks/celtic.c
+++ b/hacks/celtic.c
@@ -978,7 +978,9 @@ celtic_draw (Display *dpy, Window window, void *closure)
     st->force_reset = 0;
     st->t = 1;
 
-    pattern_del(st->pattern);
+    if (st->pattern != NULL) {
+      pattern_del(st->pattern);
+    }
     st->pattern = NULL;
     graph_del(st->graph);