From 748e2d9396a18c3fd3d07d47c1b41320acf1fbf4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 22 Aug 2012 21:50:59 +0000 Subject: [PATCH] net: reinstate rtnl in call_netdevice_notifiers() Eric Biederman pointed out that not holding RTNL while calling call_netdevice_notifiers() was racy. This patch is a direct transcription his feedback against commit 0115e8e30d6fc (net: remove delay at device dismantle) Thanks Eric ! Signed-off-by: Eric Dumazet Cc: Tom Herbert Cc: Mahesh Bandewar Cc: "Eric W. Biederman" Cc: Gao feng Acked-by: "Eric W. Biederman" Signed-off-by: David S. Miller --- net/core/dev.c | 9 +++++++-- net/core/fib_rules.c | 3 +-- net/ipv4/devinet.c | 6 +----- net/ipv4/fib_frontend.c | 7 ++----- net/ipv6/addrconf.c | 6 +----- 5 files changed, 12 insertions(+), 19 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index 0640d2a859c6..bc857fead8c8 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -1466,8 +1466,7 @@ EXPORT_SYMBOL(unregister_netdevice_notifier); int call_netdevice_notifiers(unsigned long val, struct net_device *dev) { - if (val != NETDEV_UNREGISTER_FINAL) - ASSERT_RTNL(); + ASSERT_RTNL(); return raw_notifier_call_chain(&netdev_chain, val, dev); } EXPORT_SYMBOL(call_netdevice_notifiers); @@ -5782,7 +5781,11 @@ static void netdev_wait_allrefs(struct net_device *dev) /* Rebroadcast unregister notification */ call_netdevice_notifiers(NETDEV_UNREGISTER, dev); + + __rtnl_unlock(); rcu_barrier(); + rtnl_lock(); + call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev); if (test_bit(__LINK_STATE_LINKWATCH_PENDING, &dev->state)) { @@ -5855,7 +5858,9 @@ void netdev_run_todo(void) = list_first_entry(&list, struct net_device, todo_list); list_del(&dev->todo_list); + rtnl_lock(); call_netdevice_notifiers(NETDEV_UNREGISTER_FINAL, dev); + __rtnl_unlock(); if (unlikely(dev->reg_state != NETREG_UNREGISTERING)) { pr_err("network todo '%s' but state %d\n", diff --git a/net/core/fib_rules.c b/net/core/fib_rules.c index 585093755c23..ab7db83236c9 100644 --- a/net/core/fib_rules.c +++ b/net/core/fib_rules.c @@ -711,16 +711,15 @@ static int fib_rules_event(struct notifier_block *this, unsigned long event, struct net *net = dev_net(dev); struct fib_rules_ops *ops; + ASSERT_RTNL(); switch (event) { case NETDEV_REGISTER: - ASSERT_RTNL(); list_for_each_entry(ops, &net->rules_ops, list) attach_rules(&ops->rules_list, dev); break; case NETDEV_UNREGISTER: - ASSERT_RTNL(); list_for_each_entry(ops, &net->rules_ops, list) detach_rules(&ops->rules_list, dev); break; diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index 6a5e6e4b142c..adf273f8ad2e 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -1147,12 +1147,8 @@ static int inetdev_event(struct notifier_block *this, unsigned long event, void *ptr) { struct net_device *dev = ptr; - struct in_device *in_dev; - - if (event == NETDEV_UNREGISTER_FINAL) - goto out; + struct in_device *in_dev = __in_dev_get_rtnl(dev); - in_dev = __in_dev_get_rtnl(dev); ASSERT_RTNL(); if (!in_dev) { diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c index fd7d9ae64f16..acdee325d972 100644 --- a/net/ipv4/fib_frontend.c +++ b/net/ipv4/fib_frontend.c @@ -1050,9 +1050,6 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo return NOTIFY_DONE; } - if (event == NETDEV_UNREGISTER_FINAL) - return NOTIFY_DONE; - in_dev = __in_dev_get_rtnl(dev); switch (event) { @@ -1064,14 +1061,14 @@ static int fib_netdev_event(struct notifier_block *this, unsigned long event, vo fib_sync_up(dev); #endif atomic_inc(&net->ipv4.dev_addr_genid); - rt_cache_flush(dev_net(dev), -1); + rt_cache_flush(net, -1); break; case NETDEV_DOWN: fib_disable_ip(dev, 0, 0); break; case NETDEV_CHANGEMTU: case NETDEV_CHANGE: - rt_cache_flush(dev_net(dev), 0); + rt_cache_flush(net, 0); break; } return NOTIFY_DONE; diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index e581009cb09e..6bc85f7c31e3 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -2566,14 +2566,10 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event, void *data) { struct net_device *dev = (struct net_device *) data; - struct inet6_dev *idev; + struct inet6_dev *idev = __in6_dev_get(dev); int run_pending = 0; int err; - if (event == NETDEV_UNREGISTER_FINAL) - return NOTIFY_DONE; - - idev = __in6_dev_get(dev); switch (event) { case NETDEV_REGISTER: if (!idev && dev->mtu >= IPV6_MIN_MTU) { -- 2.20.1