5.15-stable review patch. If anyone has any objections, please let me know.
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From: Tonghao Zhang tonghao@bamaicloud.com
commit 10843e1492e474c02b91314963161731fa92af91 upstream.
If the send_peer_notif counter and the peer event notify are not synchronized. It may cause problems such as the loss or dup of peer notify event.
Before this patch: - If should_notify_peers is true and the lock for send_peer_notif-- fails, peer event may be sent again in next mii_monitor loop, because should_notify_peers is still true. - If should_notify_peers is true and the lock for send_peer_notif-- succeeded, but the lock for peer event fails, the peer event will be lost.
This patch locks the RTNL for send_peer_notif, events, and commit simultaneously.
Fixes: 07a4ddec3ce9 ("bonding: add an option to specify a delay between peer notifications") Cc: Jay Vosburgh jv@jvosburgh.net Cc: Andrew Lunn andrew+netdev@lunn.ch Cc: Eric Dumazet edumazet@google.com Cc: Jakub Kicinski kuba@kernel.org Cc: Paolo Abeni pabeni@redhat.com Cc: Hangbin Liu liuhangbin@gmail.com Cc: Nikolay Aleksandrov razor@blackwall.org Cc: Vincent Bernat vincent@bernat.ch Cc: stable@vger.kernel.org Signed-off-by: Tonghao Zhang tonghao@bamaicloud.com Acked-by: Jay Vosburgh jv@jvosburgh.net Link: https://patch.msgid.link/20251021050933.46412-1-tonghao@bamaicloud.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/bonding/bond_main.c | 40 ++++++++++++++++++---------------------- 1 file changed, 18 insertions(+), 22 deletions(-)
--- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -2734,7 +2734,7 @@ static void bond_mii_monitor(struct work { struct bonding *bond = container_of(work, struct bonding, mii_work.work); - bool should_notify_peers = false; + bool should_notify_peers; bool commit; unsigned long delay; struct slave *slave; @@ -2746,30 +2746,33 @@ static void bond_mii_monitor(struct work goto re_arm;
rcu_read_lock(); + should_notify_peers = bond_should_notify_peers(bond); commit = !!bond_miimon_inspect(bond); - if (bond->send_peer_notif) { - rcu_read_unlock(); - if (rtnl_trylock()) { - bond->send_peer_notif--; - rtnl_unlock(); - } - } else { - rcu_read_unlock(); - }
- if (commit) { + rcu_read_unlock(); + + if (commit || bond->send_peer_notif) { /* Race avoidance with bond_close cancel of workqueue */ if (!rtnl_trylock()) { delay = 1; - should_notify_peers = false; goto re_arm; }
- bond_for_each_slave(bond, slave, iter) { - bond_commit_link_state(slave, BOND_SLAVE_NOTIFY_LATER); + if (commit) { + bond_for_each_slave(bond, slave, iter) { + bond_commit_link_state(slave, + BOND_SLAVE_NOTIFY_LATER); + } + bond_miimon_commit(bond); + } + + if (bond->send_peer_notif) { + bond->send_peer_notif--; + if (should_notify_peers) + call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, + bond->dev); } - bond_miimon_commit(bond);
rtnl_unlock(); /* might sleep, hold no other locks */ } @@ -2777,13 +2780,6 @@ static void bond_mii_monitor(struct work re_arm: if (bond->params.miimon) queue_delayed_work(bond->wq, &bond->mii_work, delay); - - if (should_notify_peers) { - if (!rtnl_trylock()) - return; - call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev); - rtnl_unlock(); - } }
static int bond_upper_dev_walk(struct net_device *upper,