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 <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 3da5578..70aa628 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -231,6 +231,8 @@
}
}
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();