Index: madwifi-ng-r2568-20070710/ath_rate/minstrel/minstrel.c
===================================================================
--- madwifi-ng-r2568-20070710.orig/ath_rate/minstrel/minstrel.c	2007-07-23 01:48:38.542176563 +0200
+++ madwifi-ng-r2568-20070710/ath_rate/minstrel/minstrel.c	2007-07-23 01:48:40.974315165 +0200
@@ -388,6 +388,9 @@
 		struct minstrel_node *sn = ATH_NODE_MINSTREL(an);
 		int rc1, rc2, rc3;         /* Index into the rate table, so for example, it is  0..11 */
 
+		if (sn->num_rates <= 0)
+			return;
+
 		if (sn->is_sampling) {
 			rc1 = sn->max_tp_rate;
 			sn->is_sampling = 0;