From e93737b0f0159a61772894943199fd3b6f315641 Mon Sep 17 00:00:00 2001 From: Krishna Kumar Date: Tue, 8 Dec 2009 22:26:02 +0000 Subject: net: Handle NETREG_UNINITIALIZED devices correctly Fix two problems: 1. If unregister_netdevice_many() is called with both registered and unregistered devices, rollback_registered_many() bails out when it reaches the first unregistered device. The processing of the prior registered devices is unfinished, and the remaining devices are skipped, and possible registered netdev's are leaked/unregistered. 2. System hangs or panics depending on how the devices are passed, since when netdev_run_todo() runs, some devices were not fully processed. Tested by passing intermingled unregistered and registered vlan devices to unregister_netdevice_many() as follows: 1. dev, fake_dev1, fake_dev2: hangs in run_todo ("unregister_netdevice: waiting for eth1.100 to become free. Usage count = 1") 2. fake_dev1, dev, fake_dev2: failure during de-registration and next registration, followed by a vlan driver Oops during subsequent registration. Confirmed that the patch fixes both cases. Signed-off-by: Krishna Kumar Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/core/dev.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index c36a17aafcf3..6fe7d739e59b 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -4771,21 +4771,23 @@ static void net_set_todo(struct net_device *dev) static void rollback_registered_many(struct list_head *head) { - struct net_device *dev; + struct net_device *dev, *tmp; BUG_ON(dev_boot_phase); ASSERT_RTNL(); - list_for_each_entry(dev, head, unreg_list) { + list_for_each_entry_safe(dev, tmp, head, unreg_list) { /* Some devices call without registering - * for initialization unwind. + * for initialization unwind. Remove those + * devices and proceed with the remaining. */ if (dev->reg_state == NETREG_UNINITIALIZED) { pr_debug("unregister_netdevice: device %s/%p never " "was registered\n", dev->name, dev); WARN_ON(1); - return; + list_del(&dev->unreg_list); + continue; } BUG_ON(dev->reg_state != NETREG_REGISTERED); -- cgit v1.2.3 From d90a909e1f3e006a1d57fe11fd417173b6494701 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 12 Dec 2009 22:11:15 +0000 Subject: net: Fix userspace RTM_NEWLINK notifications. I received some bug reports about userspace programs having problems because after RTM_NEWLINK was received they could not immediate access files under /proc/sys/net/ because they had not been registered yet. The original problem was trivially fixed by moving the userspace notification from rtnetlink_event() to the end of register_netdevice(). When testing that change I discovered I was still getting RTM_NEWLINK events before I could access proc and I was also getting RTM_NEWLINK events after I was seeing RTM_DELLINK. Things practically guaranteed to confuse userspace. After a little more investigation these extra notifications proved to be from the new notifiers NETDEV_POST_INIT and NETDEV_UNREGISTER_BATCH hitting the default case in rtnetlink_event, and triggering unnecessary RTM_NEWLINK messages. rtnetlink_event now explicitly handles NETDEV_UNREGISTER_BATCH and NETDEV_POST_INIT to avoid sending the incorrect userspace notifications. Signed-off-by: Eric W. Biederman Signed-off-by: David S. Miller --- net/core/dev.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'net/core/dev.c') diff --git a/net/core/dev.c b/net/core/dev.c index 6fe7d739e59b..be9924f60ec3 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -5035,6 +5035,11 @@ int register_netdevice(struct net_device *dev) rollback_registered(dev); dev->reg_state = NETREG_UNREGISTERED; } + /* + * Prevent userspace races by waiting until the network + * device is fully setup before sending notifications. + */ + rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U); out: return ret; @@ -5597,6 +5602,12 @@ int dev_change_net_namespace(struct net_device *dev, struct net *net, const char /* Notify protocols, that a new device appeared. */ call_netdevice_notifiers(NETDEV_REGISTER, dev); + /* + * Prevent userspace races by waiting until the network + * device is fully setup before sending notifications. + */ + rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U); + synchronize_net(); err = 0; out: -- cgit v1.2.3