During testing of VLAN I came across some problems concerning reference counts on netdevices. If you try to remove a VLAN device with vconfig rem it can happen that the session hangs for up to 30 seconds and waits for references (unregister_netdev waits) on the netdevice that is to be unregistered. These references are hold by routing entries as part of IPv6 neighbour discovery. The same problem occurs if a device driver wants to unregister a netdevice. The problem is that ndisc does not handle the NETDEVICE_DOWN and NETDEVICE_UNREGISTER events. As a result, routing entries related to the removed device are not deleted immediately. Instead they are freed in a deferred way by the garbage collector (fib6_gc_run). I tested on s390x, but the problem should not be arch-specify. The patch against 2.6.4 below adds the missing event handling to ndisc. -- Regards, Thomas. --- linux-2.6.4/net/ipv6/ndisc.c 2004-03-11 03:55:33.000000000 +0100 +++ linux-2.6.4-ndisc/net/ipv6/ndisc.c 2004-04-01 15:56:28.000000000 +0200 @@ -1403,6 +1403,13 @@ neigh_changeaddr(&nd_tbl, dev); fib6_run_gc(0); break; + case NETDEV_DOWN: + neigh_ifdown(&nd_tbl, dev); + fib6_run_gc(0); + break; + case NETDEV_UNREGISTER: + fib6_run_gc(0); + break; default: break; } - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
