The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From c511819d138de38e1637eedb645c207e09680d0f Mon Sep 17 00:00:00 2001

From: Joakim Zhang qiangqing.zhang@nxp.com Date: Thu, 25 Feb 2021 17:01:11 +0800 Subject: [PATCH] net: stmmac: fix watchdog timeout during suspend/resume stress test

stmmac_xmit() call stmmac_tx_timer_arm() at the end to modify tx timer to do the transmission cleanup work. Imagine such a situation, stmmac enters suspend immediately after tx timer modified, it's expire callback stmmac_tx_clean() would not be invoked. This could affect BQL, since netdev_tx_sent_queue() has been called, but netdev_tx_completed_queue() have not been involved, as a result, dql_avail(&dev_queue->dql) finally always return a negative value.

__dev_queue_xmit->__dev_xmit_skb->qdisc_run->__qdisc_run->qdisc_restart->dequeue_skb: if ((q->flags & TCQ_F_ONETXQUEUE) && netif_xmit_frozen_or_stopped(txq)) // __QUEUE_STATE_STACK_XOFF is set

Net core will stop transmitting any more. Finillay, net watchdong would timeout. To fix this issue, we should call netdev_tx_reset_queue() in stmmac_resume().

Fixes: 54139cf3bb33 ("net: stmmac: adding multiple buffers for rx") Signed-off-by: Joakim Zhang qiangqing.zhang@nxp.com Signed-off-by: Jakub Kicinski kuba@kernel.org

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 26b971cd4da5..12ed337a239b 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -5257,6 +5257,8 @@ static void stmmac_reset_queues_param(struct stmmac_priv *priv) tx_q->cur_tx = 0; tx_q->dirty_tx = 0; tx_q->mss = 0; + + netdev_tx_reset_queue(netdev_get_tx_queue(priv->dev, queue)); } }