Index: madwifi-ng-r2834-20071106/ath/if_ath.c
===================================================================
--- madwifi-ng-r2834-20071106.orig/ath/if_ath.c	2007-11-07 14:02:03.853590479 +0100
+++ madwifi-ng-r2834-20071106/ath/if_ath.c	2007-11-07 14:02:04.077603246 +0100
@@ -4162,6 +4162,8 @@
 	}
 	bf = avp->av_bcbuf;
 	ni = bf->bf_node;
+	if (!ni)
+		return NULL;
 
 #ifdef ATH_SUPERG_DYNTURBO
 	/*