diff --git a/rsvg-filter.c b/rsvg-filter.c
index 705f14c..a500fba 100644
--- a/rsvg-filter.c
+++ b/rsvg-filter.c
@@ -1373,7 +1373,7 @@ fast_blur (GdkPixbuf * in, GdkPixbuf * output, gfloat sx,
     ky = floor (sy * 3 * sqrt (2 * M_PI) / 4 + 0.5);
 
     if (kx < 1 && ky < 1)
-        return;
+        kx = ky = 1;
 
     intermediate = g_new (guchar, MAX (kx, ky));
 
