From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ding Tianhong Subject: [PATCH net] bonding: Fix deadlock in bonding driver when using netpoll Date: Wed, 12 Feb 2014 12:06:40 +0800 Message-ID: <52FAF350.80005@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit To: Jay Vosburgh , Veaceslav Falico , Andy Gospodarek , "David S. Miller" , Netdev Return-path: Received: from szxga03-in.huawei.com ([119.145.14.66]:62272 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750807AbaBLEHl (ORCPT ); Tue, 11 Feb 2014 23:07:41 -0500 Sender: netdev-owner@vger.kernel.org List-ID: The bonding driver take write locks and spin locks that are shared by the tx path in enslave processing and notification processing, If the netconsole is in use, the bonding can call printk which puts us in the netpoll tx path, if the netconsole is attached to the bonding driver, result in deadlock. So add protection for these place, by checking the netpoll_block_tx state, we can defer the sending of the netconsole frames until a later time using the retransmit feature of netpoll_send_skb that is triggered on the return code NETDEV_TX_BUSY. Cc: Jay Vosburgh Cc: Veaceslav Falico Cc: Andy Gospodarek Signed-off-by: Ding Tianhong --- drivers/net/bonding/bond_main.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 71ba18e..8676649 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -1543,9 +1543,11 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev) bond_set_carrier(bond); if (USES_PRIMARY(bond->params.mode)) { + block_netpoll_tx(); write_lock_bh(&bond->curr_slave_lock); bond_select_active_slave(bond); write_unlock_bh(&bond->curr_slave_lock); + unblock_netpoll_tx(); } pr_info("%s: enslaving %s as a%s interface with a%s link.\n", @@ -1571,10 +1573,12 @@ err_detach: if (bond->primary_slave == new_slave) bond->primary_slave = NULL; if (bond->curr_active_slave == new_slave) { + block_netpoll_tx(); write_lock_bh(&bond->curr_slave_lock); bond_change_active_slave(bond, NULL); bond_select_active_slave(bond); write_unlock_bh(&bond->curr_slave_lock); + unblock_netpoll_tx(); } slave_disable_netpoll(new_slave); @@ -2864,9 +2868,12 @@ static int bond_slave_netdev_event(unsigned long event, pr_info("%s: Primary slave changed to %s, reselecting active slave.\n", bond->dev->name, bond->primary_slave ? slave_dev->name : "none"); + + block_netpoll_tx(); write_lock_bh(&bond->curr_slave_lock); bond_select_active_slave(bond); write_unlock_bh(&bond->curr_slave_lock); + unblock_netpoll_tx(); break; case NETDEV_FEAT_CHANGE: bond_compute_features(bond); -- 1.8.0