Index: madwifi-ng-r2568-20070710/ath/if_ath.c
===================================================================
--- madwifi-ng-r2568-20070710.orig/ath/if_ath.c	2007-07-19 16:58:58.416164190 +0200
+++ madwifi-ng-r2568-20070710/ath/if_ath.c	2007-07-19 16:59:28.677888709 +0200
@@ -4027,6 +4027,8 @@
 	}
 	bf = avp->av_bcbuf;
 	ni = bf->bf_node;
+	if (!ni)
+		return NULL;
 
 #ifdef ATH_SUPERG_DYNTURBO
 	/*