From: Eric W. Biederman Date: Thu, 20 Oct 2011 04:26:01 +0000 (+0000) Subject: macvtap: Close a race between macvtap_open and macvtap_dellink. X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=99f34b38cdc8f75a4b9adb5a617b118253b3efe1;p=deliverable%2Flinux.git macvtap: Close a race between macvtap_open and macvtap_dellink. There is a small window in macvtap_open between looking up a networking device and calling macvtap_set_queue in which macvtap_del_queues called from macvtap_dellink. After calling macvtap_del_queues it is totally incorrect to allow macvtap_set_queue to proceed so prevent success by reporting that all of the available queues are in use. Signed-off-by: Eric W. Biederman Signed-off-by: David S. Miller --- diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 3da557830937..70aa628834f0 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -231,6 +231,8 @@ static void macvtap_del_queues(struct net_device *dev) } } BUG_ON(vlan->numvtaps != 0); + /* guarantee that any future macvtap_set_queue will fail */ + vlan->numvtaps = MAX_MACVTAP_QUEUES; spin_unlock(&macvtap_lock); synchronize_rcu();