This reverts: 152f253152cc net: Remove rtnl_lock() in nf_ct_iterate_destroy() ec9c780925c5 ovs: Remove rtnl_lock() from ovs_exit_net() 350311aab4c0 security: Remove rtnl_lock() in selinux_xfrm_notify_policyload() 10256debb918 net: Don't take rtnl_lock() in wireless_nlevent_flush() f0b07bb151b0 net: Introduce net_rwsem to protect net_namespace_list
There are missed, that down_read() can't be taken recursive. This is because of rw_semaphore design, which prevents it to be occupied by only readers forever. So, we can't take it in register_netdevice_notifier(), as it's also taken in wext_netdev_notifier_call()->wireless_nlevent_flush(). The solution is to protect net_namespace_list modifications in register_netdevice_notifier() via pernet_ops_rwsem, as it's made in: https://patchwork.ozlabs.org/project/netdev/list/?series=36495 Then, we won't have to take net_rwsem in call_netevent_notifiers(). But since the patchset is not in kernel, let's just revert net_rwsem for now, and I'll resubmit it later (after the above patchset). Signed-off-by: Kirill Tkhai <ktk...@virtuozzo.com> --- drivers/infiniband/core/roce_gid_mgmt.c | 2 -- include/linux/rtnetlink.h | 1 - include/net/net_namespace.h | 1 - net/core/dev.c | 5 ----- net/core/fib_notifier.c | 2 -- net/core/net_namespace.c | 18 +++++------------- net/core/rtnetlink.c | 5 ----- net/netfilter/nf_conntrack_core.c | 4 ++-- net/openvswitch/datapath.c | 4 ++-- net/wireless/wext-core.c | 6 ++++-- security/selinux/include/xfrm.h | 4 ++-- 11 files changed, 15 insertions(+), 37 deletions(-) diff --git a/drivers/infiniband/core/roce_gid_mgmt.c b/drivers/infiniband/core/roce_gid_mgmt.c index cc2966380c0c..5a52ec77940a 100644 --- a/drivers/infiniband/core/roce_gid_mgmt.c +++ b/drivers/infiniband/core/roce_gid_mgmt.c @@ -403,12 +403,10 @@ static void enum_all_gids_of_dev_cb(struct ib_device *ib_dev, * our feet */ rtnl_lock(); - down_read(&net_rwsem); for_each_net(net) for_each_netdev(net, ndev) if (is_eth_port_of_netdev(ib_dev, port, rdma_ndev, ndev)) add_netdev_ips(ib_dev, port, rdma_ndev, ndev); - up_read(&net_rwsem); rtnl_unlock(); } diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 5225832bd6ff..c7d1e4689325 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -37,7 +37,6 @@ extern int rtnl_lock_killable(void); extern wait_queue_head_t netdev_unregistering_wq; extern struct rw_semaphore pernet_ops_rwsem; -extern struct rw_semaphore net_rwsem; #ifdef CONFIG_PROVE_LOCKING extern bool lockdep_rtnl_is_held(void); diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h index 47e35cce3b64..1ab4f920f109 100644 --- a/include/net/net_namespace.h +++ b/include/net/net_namespace.h @@ -291,7 +291,6 @@ static inline struct net *read_pnet(const possible_net_t *pnet) #endif } -/* Protected by net_rwsem */ #define for_each_net(VAR) \ list_for_each_entry(VAR, &net_namespace_list, list) diff --git a/net/core/dev.c b/net/core/dev.c index eca5458b2753..e13807b5c84d 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1629,7 +1629,6 @@ int register_netdevice_notifier(struct notifier_block *nb) goto unlock; if (dev_boot_phase) goto unlock; - down_read(&net_rwsem); for_each_net(net) { for_each_netdev(net, dev) { err = call_netdevice_notifier(nb, NETDEV_REGISTER, dev); @@ -1643,7 +1642,6 @@ int register_netdevice_notifier(struct notifier_block *nb) call_netdevice_notifier(nb, NETDEV_UP, dev); } } - up_read(&net_rwsem); unlock: rtnl_unlock(); @@ -1666,7 +1664,6 @@ int register_netdevice_notifier(struct notifier_block *nb) } outroll: - up_read(&net_rwsem); raw_notifier_chain_unregister(&netdev_chain, nb); goto unlock; } @@ -1697,7 +1694,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb) if (err) goto unlock; - down_read(&net_rwsem); for_each_net(net) { for_each_netdev(net, dev) { if (dev->flags & IFF_UP) { @@ -1708,7 +1704,6 @@ int unregister_netdevice_notifier(struct notifier_block *nb) call_netdevice_notifier(nb, NETDEV_UNREGISTER, dev); } } - up_read(&net_rwsem); unlock: rtnl_unlock(); return err; diff --git a/net/core/fib_notifier.c b/net/core/fib_notifier.c index 13a40b831d6d..b793b523aba3 100644 --- a/net/core/fib_notifier.c +++ b/net/core/fib_notifier.c @@ -39,7 +39,6 @@ static unsigned int fib_seq_sum(void) struct net *net; rtnl_lock(); - down_read(&net_rwsem); for_each_net(net) { rcu_read_lock(); list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) { @@ -50,7 +49,6 @@ static unsigned int fib_seq_sum(void) } rcu_read_unlock(); } - up_read(&net_rwsem); rtnl_unlock(); return fib_seq; diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 7fdf321d4997..b5796d17a302 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -33,10 +33,6 @@ static struct list_head *first_device = &pernet_list; LIST_HEAD(net_namespace_list); EXPORT_SYMBOL_GPL(net_namespace_list); -/* Protects net_namespace_list. Nests iside rtnl_lock() */ -DECLARE_RWSEM(net_rwsem); -EXPORT_SYMBOL_GPL(net_rwsem); - struct net init_net = { .count = REFCOUNT_INIT(1), .dev_base_head = LIST_HEAD_INIT(init_net.dev_base_head), @@ -313,9 +309,9 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) if (error < 0) goto out_undo; } - down_write(&net_rwsem); + rtnl_lock(); list_add_tail_rcu(&net->list, &net_namespace_list); - up_write(&net_rwsem); + rtnl_unlock(); out: return error; @@ -454,7 +450,7 @@ static void unhash_nsid(struct net *net, struct net *last) * and this work is the only process, that may delete * a net from net_namespace_list. So, when the below * is executing, the list may only grow. Thus, we do not - * use for_each_net_rcu() or net_rwsem. + * use for_each_net_rcu() or rtnl_lock(). */ for_each_net(tmp) { int id; @@ -489,7 +485,7 @@ static void cleanup_net(struct work_struct *work) down_read(&pernet_ops_rwsem); /* Don't let anyone else find us. */ - down_write(&net_rwsem); + rtnl_lock(); llist_for_each_entry(net, net_kill_list, cleanup_list) list_del_rcu(&net->list); /* Cache last net. After we unlock rtnl, no one new net @@ -503,7 +499,7 @@ static void cleanup_net(struct work_struct *work) * useless anyway, as netns_ids are destroyed there. */ last = list_last_entry(&net_namespace_list, struct net, list); - up_write(&net_rwsem); + rtnl_unlock(); llist_for_each_entry(net, net_kill_list, cleanup_list) { unhash_nsid(net, last); @@ -904,9 +900,6 @@ static int __register_pernet_operations(struct list_head *list, list_add_tail(&ops->list, list); if (ops->init || (ops->id && ops->size)) { - /* We held write locked pernet_ops_rwsem, and parallel - * setup_net() and cleanup_net() are not possible. - */ for_each_net(net) { error = ops_init(ops, net); if (error) @@ -930,7 +923,6 @@ static void __unregister_pernet_operations(struct pernet_operations *ops) LIST_HEAD(net_exit_list); list_del(&ops->list); - /* See comment in __register_pernet_operations() */ for_each_net(net) list_add_tail(&net->exit_list, &net_exit_list); ops_exit_list(ops, &net_exit_list); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index e86b28482ca7..2d3949789cef 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -418,11 +418,9 @@ void __rtnl_link_unregister(struct rtnl_link_ops *ops) { struct net *net; - down_read(&net_rwsem); for_each_net(net) { __rtnl_kill_links(net, ops); } - up_read(&net_rwsem); list_del(&ops->list); } EXPORT_SYMBOL_GPL(__rtnl_link_unregister); @@ -440,9 +438,6 @@ static void rtnl_lock_unregistering_all(void) for (;;) { unregistering = false; rtnl_lock(); - /* We held write locked pernet_ops_rwsem, and parallel - * setup_net() and cleanup_net() are not possible. - */ for_each_net(net) { if (net->dev_unreg_count > 0) { unregistering = true; diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 41ff04ee2554..705198de671d 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -1763,14 +1763,14 @@ nf_ct_iterate_destroy(int (*iter)(struct nf_conn *i, void *data), void *data) { struct net *net; - down_read(&net_rwsem); + rtnl_lock(); for_each_net(net) { if (atomic_read(&net->ct.count) == 0) continue; __nf_ct_unconfirmed_destroy(net); nf_queue_nf_hook_drop(net); } - up_read(&net_rwsem); + rtnl_unlock(); /* Need to wait for netns cleanup worker to finish, if its * running -- it might have deleted a net namespace from diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index 015e24e08909..ef38e5aecd28 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -2363,10 +2363,10 @@ static void __net_exit ovs_exit_net(struct net *dnet) list_for_each_entry_safe(dp, dp_next, &ovs_net->dps, list_node) __dp_destroy(dp); - down_read(&net_rwsem); + rtnl_lock(); for_each_net(net) list_vports_from_net(net, dnet, &head); - up_read(&net_rwsem); + rtnl_unlock(); /* Detach all vports from given namespace. */ list_for_each_entry_safe(vport, vport_next, &head, detach_list) { diff --git a/net/wireless/wext-core.c b/net/wireless/wext-core.c index 5e677dac2a0c..9efbfc753347 100644 --- a/net/wireless/wext-core.c +++ b/net/wireless/wext-core.c @@ -347,13 +347,13 @@ void wireless_nlevent_flush(void) struct sk_buff *skb; struct net *net; - down_read(&net_rwsem); + ASSERT_RTNL(); + for_each_net(net) { while ((skb = skb_dequeue(&net->wext_nlevents))) rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_KERNEL); } - up_read(&net_rwsem); } EXPORT_SYMBOL_GPL(wireless_nlevent_flush); @@ -410,7 +410,9 @@ subsys_initcall(wireless_nlevent_init); /* Process events generated by the wireless layer or the driver. */ static void wireless_nlevent_process(struct work_struct *work) { + rtnl_lock(); wireless_nlevent_flush(); + rtnl_unlock(); } static DECLARE_WORK(wireless_nlevent_work, wireless_nlevent_process); diff --git a/security/selinux/include/xfrm.h b/security/selinux/include/xfrm.h index a0b465316292..1f173a7a4daa 100644 --- a/security/selinux/include/xfrm.h +++ b/security/selinux/include/xfrm.h @@ -47,10 +47,10 @@ static inline void selinux_xfrm_notify_policyload(void) { struct net *net; - down_read(&net_rwsem); + rtnl_lock(); for_each_net(net) rt_genid_bump_all(net); - up_read(&net_rwsem); + rtnl_unlock(); } #else static inline int selinux_xfrm_enabled(void)
