From: dingtianhong Date: Wed, 12 Feb 2014 04:06:40 +0000 (+0800) Subject: bonding: Fix deadlock in bonding driver when using netpoll X-Git-Tag: v3.14-rc4~30^2~39 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f80889a5b79cae0b84465a90c21b1273a03b7973;p=pandora-kernel.git bonding: Fix deadlock in bonding driver when using netpoll 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 Signed-off-by: David S. Miller --- diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 71ba18efa15b..867664918715 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);