This is a note to let you know that I've just added the patch titled tun: fix bonding active backup with arp monitoring to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tun-fix-bonding-active-backup-with-arp-monitoring.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a31d27fbed5d518734cb60956303eb15089a7634 Mon Sep 17 00:00:00 2001 From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx> Date: Fri, 12 Nov 2021 08:56:03 +0100 Subject: tun: fix bonding active backup with arp monitoring From: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx> commit a31d27fbed5d518734cb60956303eb15089a7634 upstream. As stated in the bonding doc, trans_start must be set manually for drivers using NETIF_F_LLTX: Drivers that use NETIF_F_LLTX flag must also update netdev_queue->trans_start. If they do not, then the ARP monitor will immediately fail any slaves using that driver, and those slaves will stay down. Link: https://www.kernel.org/doc/html/v5.15/networking/bonding.html#arp-monitor-operation Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/tun.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1021,6 +1021,7 @@ static netdev_tx_t tun_net_xmit(struct s { struct tun_struct *tun = netdev_priv(dev); int txq = skb->queue_mapping; + struct netdev_queue *queue; struct tun_file *tfile; int len = skb->len; @@ -1065,6 +1066,10 @@ static netdev_tx_t tun_net_xmit(struct s if (ptr_ring_produce(&tfile->tx_ring, skb)) goto drop; + /* NETIF_F_LLTX requires to do our own update of trans_start */ + queue = netdev_get_tx_queue(dev, txq); + queue->trans_start = jiffies; + /* Notify and wake up reader process */ if (tfile->flags & TUN_FASYNC) kill_fasync(&tfile->fasync, SIGIO, POLL_IN); Patches currently in stable-queue which might be from nicolas.dichtel@xxxxxxxxx are queue-5.10/tun-fix-bonding-active-backup-with-arp-monitoring.patch