Index: debian/ifupdown/functions.sh
===================================================================
--- debian/ifupdown/functions.sh	(revision 1965)
+++ debian/ifupdown/functions.sh	(working copy)
@@ -951,6 +951,9 @@
 
 		wpa_msg log "ifup $WPA_IFACE=$WPA_LOGICAL_IFACE"
 
+		# Remove the environment variable used by ifup to check for recursive loops
+		unset "IFUPDOWN_$WPA_IFACE"
+
 		ifupdown_lock
 
 		if [ -n "$IFSTATE_FILE" ] && grep -q "^$WPA_IFACE=$WPA_IFACE" "$IFSTATE_FILE"; then