Index: madwifi-ng-r2525-20070630/ath_rate/minstrel/minstrel.c
===================================================================
--- madwifi-ng-r2525-20070630.orig/ath_rate/minstrel/minstrel.c	2007-07-03 23:02:26.041671250 +0200
+++ madwifi-ng-r2525-20070630/ath_rate/minstrel/minstrel.c	2007-07-03 23:02:28.825845250 +0200
@@ -389,6 +389,9 @@
 		int rc1, rc2, rc3;         /* Index into the rate table, so for example, it is  0..11 */
 		int rixc1, rixc2, rixc3;   /* The actual bit rate used */
 
+		if (sn->num_rates <= 0)
+			return;
+
 		if (sn->is_sampling) {
 			rc1 = sn->max_tp_rate;
 			sn->is_sampling = 0;