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authorEric W. Biederman <ebiederm@xmission.com>2009-12-12 22:11:15 +0000
committerDavid S. Miller <davem@davemloft.net>2009-12-13 19:45:22 -0800
commitd90a909e1f3e006a1d57fe11fd417173b6494701 (patch)
tree72893da9ed5083b44dbb8d778d648e114d351a0a /net
parent5781b2356cbecb0b73b06ec8c3897cabdfdd0928 (diff)
downloadop-kernel-dev-d90a909e1f3e006a1d57fe11fd417173b6494701.zip
op-kernel-dev-d90a909e1f3e006a1d57fe11fd417173b6494701.tar.gz
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 <ebiederm@aristanetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/dev.c11
-rw-r--r--net/core/rtnetlink.c6
2 files changed, 14 insertions, 3 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 6fe7d73..be9924f 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:
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 33148a5..794bcb8 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1364,15 +1364,15 @@ static int rtnetlink_event(struct notifier_block *this, unsigned long event, voi
case NETDEV_UNREGISTER:
rtmsg_ifinfo(RTM_DELLINK, dev, ~0U);
break;
- case NETDEV_REGISTER:
- rtmsg_ifinfo(RTM_NEWLINK, dev, ~0U);
- break;
case NETDEV_UP:
case NETDEV_DOWN:
rtmsg_ifinfo(RTM_NEWLINK, dev, IFF_UP|IFF_RUNNING);
break;
+ case NETDEV_POST_INIT:
+ case NETDEV_REGISTER:
case NETDEV_CHANGE:
case NETDEV_GOING_DOWN:
+ case NETDEV_UNREGISTER_BATCH:
break;
default:
rtmsg_ifinfo(RTM_NEWLINK, dev, 0);
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