From 5e5b066535f0ee58e5de3a2db5fb56fa3cd7e3b1 Mon Sep 17 00:00:00 2001 From: dingtianhong Date: Wed, 26 Feb 2014 11:05:22 +0800 Subject: bonding: Fix RTNL: assertion failed at net/core/rtnetlink.c for 802.3ad mode The problem was introduced by the commit 1d3ee88ae0d (bonding: add netlink attributes to slave link dev). The bond_set_active_slave() and bond_set_backup_slave() will use rtmsg_ifinfo to send slave's states, so these two functions should be called in RTNL. In 802.3ad mode, acquiring RTNL for the __enable_port and __disable_port cases is difficult, as those calls generally already hold the state machine lock, and cannot unconditionally call rtnl_lock because either they already hold RTNL (for calls via bond_3ad_unbind_slave) or due to the potential for deadlock with bond_3ad_adapter_speed_changed, bond_3ad_adapter_duplex_changed, bond_3ad_link_change, or bond_3ad_update_lacp_rate. All four of those are called with RTNL held, and acquire the state machine lock second. The calling contexts for __enable_port and __disable_port already hold the state machine lock, and may or may not need RTNL. According to the Jay's opinion, I don't think it is a problem that the slave don't send notify message synchronously when the status changed, normally the state machine is running every 100 ms, send the notify message at the end of the state machine if the slave's state changed should be better. I fix the problem through these steps: 1). add a new function bond_set_slave_state() which could change the slave's state and call rtmsg_ifinfo() according to the input parameters called notify. 2). Add a new slave parameter which called should_notify, if the slave's state changed and don't notify yet, the parameter will be set to 1, and then if the slave's state changed again, the param will be set to 0, it indicate that the slave's state has been restored, no need to notify any one. 3). the __enable_port and __disable_port should not call rtmsg_ifinfo in the state machine lock, any change in the state of slave could set a flag in the slave, it will indicated that an rtmsg_ifinfo should be called at the end of the state machine. Cc: Jay Vosburgh Cc: Veaceslav Falico Cc: Andy Gospodarek Signed-off-by: Ding Tianhong Signed-off-by: David S. Miller --- drivers/net/bonding/bond_3ad.c | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) (limited to 'drivers/net/bonding/bond_3ad.c') diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c index 6d20fbde8d43..6826e4f61060 100644 --- a/drivers/net/bonding/bond_3ad.c +++ b/drivers/net/bonding/bond_3ad.c @@ -181,7 +181,7 @@ static inline int __agg_has_partner(struct aggregator *agg) */ static inline void __disable_port(struct port *port) { - bond_set_slave_inactive_flags(port->slave); + bond_set_slave_inactive_flags(port->slave, BOND_SLAVE_NOTIFY_LATER); } /** @@ -193,7 +193,7 @@ static inline void __enable_port(struct port *port) struct slave *slave = port->slave; if ((slave->link == BOND_LINK_UP) && IS_UP(slave->dev)) - bond_set_slave_active_flags(slave); + bond_set_slave_active_flags(slave, BOND_SLAVE_NOTIFY_LATER); } /** @@ -2062,6 +2062,7 @@ void bond_3ad_state_machine_handler(struct work_struct *work) struct list_head *iter; struct slave *slave; struct port *port; + bool should_notify_rtnl = BOND_SLAVE_NOTIFY_LATER; read_lock(&bond->lock); rcu_read_lock(); @@ -2119,8 +2120,25 @@ void bond_3ad_state_machine_handler(struct work_struct *work) } re_arm: + bond_for_each_slave_rcu(bond, slave, iter) { + if (slave->should_notify) { + should_notify_rtnl = BOND_SLAVE_NOTIFY_NOW; + break; + } + } rcu_read_unlock(); read_unlock(&bond->lock); + + if (should_notify_rtnl && rtnl_trylock()) { + bond_for_each_slave(bond, slave, iter) { + if (slave->should_notify) { + rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, + GFP_KERNEL); + slave->should_notify = 0; + } + } + rtnl_unlock(); + } queue_delayed_work(bond->wq, &bond->ad_work, ad_delta_in_ticks); } -- cgit v1.2.3 From b0929915e0356acedf59504521c097ecada88b19 Mon Sep 17 00:00:00 2001 From: dingtianhong Date: Wed, 26 Feb 2014 11:05:23 +0800 Subject: bonding: Fix RTNL: assertion failed at net/core/rtnetlink.c for ab arp monitor Veaceslav has reported and fix this problem by commit f2ebd477f141bc0 (bonding: restructure locking of bond_ab_arp_probe()). According Jay's opinion, the current solution is not very well, because the notification is to indicate that the interface has actually changed state in a meaningful way, but these calls in the ab ARP monitor are internal settings of the flags to allow the ARP monitor to search for a slave to become active when there are no active slaves. The flag setting to active or backup is to permit the ARP monitor's response logic to do the right thing when deciding if the test slave (current_arp_slave) is up or not. So the best way to fix the problem is that we should not send a notification when the slave is in testing state, and check the state at the end of the monitor, if the slave's state recover, avoid to send pointless notification twice. And RTNL is really a big lock, hold it regardless the slave's state changed or not when the current_active_slave is null will loss performance (every 100ms), so we should hold it only when the slave's state changed and need to notify. I revert the old commit and add new modifications. Cc: Jay Vosburgh Cc: Veaceslav Falico Cc: Andy Gospodarek Signed-off-by: Ding Tianhong Signed-off-by: David S. Miller --- drivers/net/bonding/bond_3ad.c | 8 +---- drivers/net/bonding/bond_main.c | 80 +++++++++++++++++++++-------------------- drivers/net/bonding/bonding.h | 13 +++++++ 3 files changed, 55 insertions(+), 46 deletions(-) (limited to 'drivers/net/bonding/bond_3ad.c') diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c index 6826e4f61060..dcde56057fe1 100644 --- a/drivers/net/bonding/bond_3ad.c +++ b/drivers/net/bonding/bond_3ad.c @@ -2130,13 +2130,7 @@ re_arm: read_unlock(&bond->lock); if (should_notify_rtnl && rtnl_trylock()) { - bond_for_each_slave(bond, slave, iter) { - if (slave->should_notify) { - rtmsg_ifinfo(RTM_NEWLINK, slave->dev, 0, - GFP_KERNEL); - slave->should_notify = 0; - } - } + bond_slave_state_notify(bond); rtnl_unlock(); } queue_delayed_work(bond->wq, &bond->ad_work, ad_delta_in_ticks); diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index e02029bbf5cc..82b70ff1fd28 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -2623,17 +2623,17 @@ do_failover: /* * Send ARP probes for active-backup mode ARP monitor. + * + * Called with rcu_read_lock hold. */ static bool bond_ab_arp_probe(struct bonding *bond) { struct slave *slave, *before = NULL, *new_slave = NULL, - *curr_arp_slave, *curr_active_slave; + *curr_arp_slave = rcu_dereference(bond->current_arp_slave), + *curr_active_slave = rcu_dereference(bond->curr_active_slave); struct list_head *iter; bool found = false; - - rcu_read_lock(); - curr_arp_slave = rcu_dereference(bond->current_arp_slave); - curr_active_slave = rcu_dereference(bond->curr_active_slave); + bool should_notify_rtnl = BOND_SLAVE_NOTIFY_LATER; if (curr_arp_slave && curr_active_slave) pr_info("PROBE: c_arp %s && cas %s BAD\n", @@ -2642,32 +2642,23 @@ static bool bond_ab_arp_probe(struct bonding *bond) if (curr_active_slave) { bond_arp_send_all(bond, curr_active_slave); - rcu_read_unlock(); - return true; + return should_notify_rtnl; } - rcu_read_unlock(); /* if we don't have a curr_active_slave, search for the next available * backup slave from the current_arp_slave and make it the candidate * for becoming the curr_active_slave */ - if (!rtnl_trylock()) - return false; - /* curr_arp_slave might have gone away */ - curr_arp_slave = ACCESS_ONCE(bond->current_arp_slave); - if (!curr_arp_slave) { - curr_arp_slave = bond_first_slave(bond); - if (!curr_arp_slave) { - rtnl_unlock(); - return true; - } + curr_arp_slave = bond_first_slave_rcu(bond); + if (!curr_arp_slave) + return should_notify_rtnl; } - bond_set_slave_inactive_flags(curr_arp_slave, BOND_SLAVE_NOTIFY_NOW); + bond_set_slave_inactive_flags(curr_arp_slave, BOND_SLAVE_NOTIFY_LATER); - bond_for_each_slave(bond, slave, iter) { + bond_for_each_slave_rcu(bond, slave, iter) { if (!found && !before && IS_UP(slave->dev)) before = slave; @@ -2686,7 +2677,7 @@ static bool bond_ab_arp_probe(struct bonding *bond) slave->link_failure_count++; bond_set_slave_inactive_flags(slave, - BOND_SLAVE_NOTIFY_NOW); + BOND_SLAVE_NOTIFY_LATER); pr_info("%s: backup interface %s is now down.\n", bond->dev->name, slave->dev->name); @@ -2698,26 +2689,31 @@ static bool bond_ab_arp_probe(struct bonding *bond) if (!new_slave && before) new_slave = before; - if (!new_slave) { - rtnl_unlock(); - return true; - } + if (!new_slave) + goto check_state; new_slave->link = BOND_LINK_BACK; - bond_set_slave_active_flags(new_slave, BOND_SLAVE_NOTIFY_NOW); + bond_set_slave_active_flags(new_slave, BOND_SLAVE_NOTIFY_LATER); bond_arp_send_all(bond, new_slave); new_slave->jiffies = jiffies; rcu_assign_pointer(bond->current_arp_slave, new_slave); - rtnl_unlock(); - return true; +check_state: + bond_for_each_slave_rcu(bond, slave, iter) { + if (slave->should_notify) { + should_notify_rtnl = BOND_SLAVE_NOTIFY_NOW; + break; + } + } + return should_notify_rtnl; } static void bond_activebackup_arp_mon(struct work_struct *work) { struct bonding *bond = container_of(work, struct bonding, arp_work.work); - bool should_notify_peers = false, should_commit = false; + bool should_notify_peers = false; + bool should_notify_rtnl = false; int delta_in_ticks; delta_in_ticks = msecs_to_jiffies(bond->params.arp_interval); @@ -2726,11 +2722,12 @@ static void bond_activebackup_arp_mon(struct work_struct *work) goto re_arm; rcu_read_lock(); + should_notify_peers = bond_should_notify_peers(bond); - should_commit = bond_ab_arp_inspect(bond); - rcu_read_unlock(); - if (should_commit) { + if (bond_ab_arp_inspect(bond)) { + rcu_read_unlock(); + /* Race avoidance with bond_close flush of workqueue */ if (!rtnl_trylock()) { delta_in_ticks = 1; @@ -2739,23 +2736,28 @@ static void bond_activebackup_arp_mon(struct work_struct *work) } bond_ab_arp_commit(bond); + rtnl_unlock(); + rcu_read_lock(); } - if (!bond_ab_arp_probe(bond)) { - /* rtnl locking failed, re-arm */ - delta_in_ticks = 1; - should_notify_peers = false; - } + should_notify_rtnl = bond_ab_arp_probe(bond); + rcu_read_unlock(); re_arm: if (bond->params.arp_interval) queue_delayed_work(bond->wq, &bond->arp_work, delta_in_ticks); - if (should_notify_peers) { + if (should_notify_peers || should_notify_rtnl) { if (!rtnl_trylock()) return; - call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev); + + if (should_notify_peers) + call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, + bond->dev); + if (should_notify_rtnl) + bond_slave_state_notify(bond); + rtnl_unlock(); } } diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h index 9b280ac8c454..2b0fdec695f7 100644 --- a/drivers/net/bonding/bonding.h +++ b/drivers/net/bonding/bonding.h @@ -335,6 +335,19 @@ static inline void bond_slave_state_change(struct bonding *bond) } } +static inline void bond_slave_state_notify(struct bonding *bond) +{ + struct list_head *iter; + struct slave *tmp; + + bond_for_each_slave(bond, tmp, iter) { + if (tmp->should_notify) { + rtmsg_ifinfo(RTM_NEWLINK, tmp->dev, 0, GFP_KERNEL); + tmp->should_notify = 0; + } + } +} + static inline int bond_slave_state(struct slave *slave) { return slave->backup; -- cgit v1.2.3