From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jiri Pirko Subject: [PATCH net-2.6] netns: assign NULL after pernet memory is freed Date: Mon, 26 Apr 2010 13:18:07 +0200 Message-ID: <20100426111806.GB2941@psychotron.lab.eng.brq.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, ebiederm@xmission.com To: netdev@vger.kernel.org Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45389 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752275Ab0DZLSK (ORCPT ); Mon, 26 Apr 2010 07:18:10 -0400 Content-Disposition: inline Sender: netdev-owner@vger.kernel.org List-ID: This is needed to let know appropriate code (driver) know that pernet memory chunk was freed already. For example when driver has also registered netdev notifier, it can be called after memory is freed which could eventually lead to panic. Also a null check should be present in these notifiers. For example, previously, when drivers were responsible for pernet memory allocation/freeing, in pppoe this assign was done in pppoe_exit_net() right after pernet memory was freed. The check in notifier stayed (in pppoe_flush_dev called from pppoe_device_event) but makes no sense now without this patch. I already know about several notifiers where the check should be present, patches will follow up. Signed-off-by: Jiri Pirko diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index bd8c471..29f622c 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -51,6 +51,7 @@ static void ops_free(const struct pernet_operations *ops, struct net *net) if (ops->id && ops->size) { int id = *ops->id; kfree(net_generic(net, id)); + net_assign_generic(net, id, NULL); } }