From: Fei Li lifei.shirley@bytedance.com
[ Upstream commit 72b319dc08b4924a29f5e2560ef6d966fa54c429 ]
Currently after setting tap0 link up, the tun code wakes tx/rx waited queues up in tun_net_open() when .ndo_open() is called, however the IFF_UP flag has not been set yet. If there's already a wait queue, it would fail to transmit when checking the IFF_UP flag in tun_sendmsg(). Then the saving vhost_poll_start() will add the wq into wqh until it is waken up again. Although this works when IFF_UP flag has been set when tun_chr_poll detects; this is not true if IFF_UP flag has not been set at that time. Sadly the latter case is a fatal error, as the wq will never be waken up in future unless later manually setting link up on purpose.
Fix this by moving the wakeup process into the NETDEV_UP event notifying process, this makes sure IFF_UP has been set before all waited queues been waken up.
Signed-off-by: Fei Li lifei.shirley@bytedance.com Acked-by: Jason Wang jasowang@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/tun.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)
--- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1024,18 +1024,8 @@ static void tun_net_uninit(struct net_de /* Net device open. */ static int tun_net_open(struct net_device *dev) { - struct tun_struct *tun = netdev_priv(dev); - int i; - netif_tx_start_all_queues(dev);
- for (i = 0; i < tun->numqueues; i++) { - struct tun_file *tfile; - - tfile = rtnl_dereference(tun->tfiles[i]); - tfile->socket.sk->sk_write_space(tfile->socket.sk); - } - return 0; }
@@ -3636,6 +3626,7 @@ static int tun_device_event(struct notif { struct net_device *dev = netdev_notifier_info_to_dev(ptr); struct tun_struct *tun = netdev_priv(dev); + int i;
if (dev->rtnl_link_ops != &tun_link_ops) return NOTIFY_DONE; @@ -3645,6 +3636,14 @@ static int tun_device_event(struct notif if (tun_queue_resize(tun)) return NOTIFY_BAD; break; + case NETDEV_UP: + for (i = 0; i < tun->numqueues; i++) { + struct tun_file *tfile; + + tfile = rtnl_dereference(tun->tfiles[i]); + tfile->socket.sk->sk_write_space(tfile->socket.sk); + } + break; default: break; }