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| author | Eric W. Biederman <ebiederm@xmission.com> | 2009-12-12 22:11:15 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-12-13 19:45:22 -0800 |
| commit | d90a909e1f3e006a1d57fe11fd417173b6494701 (patch) | |
| tree | 72893da9ed5083b44dbb8d778d648e114d351a0a /net/core | |
| parent | 5781b2356cbecb0b73b06ec8c3897cabdfdd0928 (diff) | |
| download | op-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/core')
| -rw-r--r-- | net/core/dev.c | 11 | ||||
| -rw-r--r-- | net/core/rtnetlink.c | 6 |
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); |
