Messages in this thread Patch in this message | | | From | Fei Li <> | Subject | [PATCH] Fix tun: wake up waitqueues after IFF_UP is set | Date | Mon, 17 Jun 2019 15:33:20 +0800 |
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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> --- drivers/net/tun.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/net/tun.c b/drivers/net/tun.c index c452d6d831dd..a3c9cab5a4d0 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1015,17 +1015,9 @@ static void tun_net_uninit(struct net_device *dev) 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; } @@ -3634,6 +3626,7 @@ static int tun_device_event(struct notifier_block *unused, { 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; @@ -3643,6 +3636,14 @@ static int tun_device_event(struct notifier_block *unused, 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; } -- 2.11.0
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