Fix for rare crash in recent mask option to check overlaps

source/blender/blenlib/intern/scanfill_utils.c

@@ -258,6 +258,12 @@ static bool scanfill_preprocess_self_isect(
 
 				LinkData *isect_link;
 
+				if (UNLIKELY(e_ls == NULL)) {
+					/* only happens in very rare cases (entirely overlapping splines).
+					 * in this case se can't do much useful. but at least don't crash */
+					continue;
+				}
+
 				/* maintain coorect terminating edge */
 				if (pi->edge_last == eed) {
 					pi->edge_last = NULL;