From a239e0625097bccdd4065390952fe9e6d0fdf02b Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 6 Jan 2025 16:07:49 +0900 Subject: [PATCH 1/3] net: Hold __rtnl_net_lock() in (un)?register_netdevice_notifier(). (un)?register_netdevice_notifier() hold pernet_ops_rwsem and RTNL, iterate all netns, and trigger the notifier for all netdev. Let's hold __rtnl_net_lock() before triggering the notifier. Note that we will need protection for netdev_chain when RTNL is removed. (e.g. blocking_notifier conversion [0] with a lockdep annotation [1]) Link: https://lore.kernel.org/netdev/20250104063735.36945-2-kuniyu@amazon.com/ [0] Link: https://lore.kernel.org/netdev/20250105075957.67334-1-kuniyu@amazon.com/ [1] Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250106070751.63146-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 2179da3dfffc..34ded7974675 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1769,14 +1769,19 @@ int register_netdevice_notifier(struct notifier_block *nb) /* Close race with setup_net() and cleanup_net() */ down_write(&pernet_ops_rwsem); + + /* When RTNL is removed, we need protection for netdev_chain. */ rtnl_lock(); + err = raw_notifier_chain_register(&netdev_chain, nb); if (err) goto unlock; if (dev_boot_phase) goto unlock; for_each_net(net) { + __rtnl_net_lock(net); err = call_netdevice_register_net_notifiers(nb, net); + __rtnl_net_unlock(net); if (err) goto rollback; } @@ -1787,8 +1792,11 @@ int register_netdevice_notifier(struct notifier_block *nb) return err; rollback: - for_each_net_continue_reverse(net) + for_each_net_continue_reverse(net) { + __rtnl_net_lock(net); call_netdevice_unregister_net_notifiers(nb, net); + __rtnl_net_unlock(net); + } raw_notifier_chain_unregister(&netdev_chain, nb); goto unlock; @@ -1821,8 +1829,11 @@ int unregister_netdevice_notifier(struct notifier_block *nb) if (err) goto unlock; - for_each_net(net) + for_each_net(net) { + __rtnl_net_lock(net); call_netdevice_unregister_net_notifiers(nb, net); + __rtnl_net_unlock(net); + } unlock: rtnl_unlock(); From ca779f40654a046613ea812126055f161844f17b Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 6 Jan 2025 16:07:50 +0900 Subject: [PATCH 2/3] net: Hold rtnl_net_lock() in (un)?register_netdevice_notifier_net(). (un)?register_netdevice_notifier_net() hold RTNL before triggering the notifier for all netdev in the netns. Let's convert the RTNL to rtnl_net_lock(). Note that the per-netns netdev notifier is protected by per-netns RTNL. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250106070751.63146-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 34ded7974675..06a5c11688c1 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1897,9 +1897,10 @@ int register_netdevice_notifier_net(struct net *net, struct notifier_block *nb) { int err; - rtnl_lock(); + rtnl_net_lock(net); err = __register_netdevice_notifier_net(net, nb, false); - rtnl_unlock(); + rtnl_net_unlock(net); + return err; } EXPORT_SYMBOL(register_netdevice_notifier_net); @@ -1925,9 +1926,10 @@ int unregister_netdevice_notifier_net(struct net *net, { int err; - rtnl_lock(); + rtnl_net_lock(net); err = __unregister_netdevice_notifier_net(net, nb); - rtnl_unlock(); + rtnl_net_unlock(net); + return err; } EXPORT_SYMBOL(unregister_netdevice_notifier_net); From 7fb1073300a2ea8bd03b2fc7d5a591192e48ea24 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Mon, 6 Jan 2025 16:07:51 +0900 Subject: [PATCH 3/3] net: Hold rtnl_net_lock() in (un)?register_netdevice_notifier_dev_net(). (un)?register_netdevice_notifier_dev_net() hold RTNL before triggering the notifier for all netdev in the netns. Let's convert the RTNL to rtnl_net_lock(). Note that move_netdevice_notifiers_dev_net() is assumed to be (but not yet) protected by per-netns RTNL of both src and dst netns; we need to convert wireless and hyperv drivers that call dev_change_net_namespace(). Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250106070751.63146-4-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- net/core/dev.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 06a5c11688c1..efbe2c4d9458 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1946,15 +1946,17 @@ int register_netdevice_notifier_dev_net(struct net_device *dev, struct notifier_block *nb, struct netdev_net_notifier *nn) { + struct net *net = dev_net(dev); int err; - rtnl_lock(); - err = __register_netdevice_notifier_net(dev_net(dev), nb, false); + rtnl_net_lock(net); + err = __register_netdevice_notifier_net(net, nb, false); if (!err) { nn->nb = nb; list_add(&nn->list, &dev->net_notifier_list); } - rtnl_unlock(); + rtnl_net_unlock(net); + return err; } EXPORT_SYMBOL(register_netdevice_notifier_dev_net); @@ -1963,12 +1965,14 @@ int unregister_netdevice_notifier_dev_net(struct net_device *dev, struct notifier_block *nb, struct netdev_net_notifier *nn) { + struct net *net = dev_net(dev); int err; - rtnl_lock(); + rtnl_net_lock(net); list_del(&nn->list); - err = __unregister_netdevice_notifier_net(dev_net(dev), nb); - rtnl_unlock(); + err = __unregister_netdevice_notifier_net(net, nb); + rtnl_net_unlock(net); + return err; } EXPORT_SYMBOL(unregister_netdevice_notifier_dev_net);