From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: [PATCH 3/6] netpoll: Don't allow on devices that perform their own xmit locking Date: Mon, 17 Mar 2014 23:25:51 -0700 Message-ID: <87wqfsf2fk.fsf_-_@xmission.com> References: <20140314.225923.61318448733570839.davem@davemloft.net> <87k3bwqgf7.fsf@xmission.com> <877g7wqg8e.fsf_-_@xmission.com> <20140317.154916.2276987764507311378.davem@davemloft.net> <87iorcgh5d.fsf_-_@xmission.com> Mime-Version: 1.0 Content-Type: text/plain Cc: stephen@networkplumber.org, eric.dumazet@gmail.com, netdev@vger.kernel.org, xiyou.wangcong@gmail.com, mpm@selenic.com, satyam.sharma@gmail.com To: David Miller Return-path: Received: from out03.mta.xmission.com ([166.70.13.233]:58300 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751787AbaCRGZ5 (ORCPT ); Tue, 18 Mar 2014 02:25:57 -0400 In-Reply-To: <87iorcgh5d.fsf_-_@xmission.com> (Eric W. Biederman's message of "Mon, 17 Mar 2014 23:22:38 -0700") Sender: netdev-owner@vger.kernel.org List-ID: There are strong and reasonable assumptions in the netpoll code that the transmit code for network devices will not perform their own locking, that can easily lead to deadlock if the assumptions are violated. Document those assumptions by verifying the network device on which netpoll is enabled does not have NETIF_F_LLTX set in netdev->features. Signed-off-by: "Eric W. Biederman" --- net/core/netpoll.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/net/core/netpoll.c b/net/core/netpoll.c index 825200fcb0ff..a9abb195a2c3 100644 --- a/net/core/netpoll.c +++ b/net/core/netpoll.c @@ -606,6 +606,7 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev) INIT_WORK(&np->cleanup_work, netpoll_async_cleanup); if ((ndev->priv_flags & IFF_DISABLE_NETPOLL) || + (ndev->features & NETIF_F_LLTX) || !ndev->netdev_ops->ndo_poll_controller) { np_err(np, "%s doesn't support polling, aborting\n", np->dev_name); -- 1.7.5.4