This is a note to let you know that I've just added the patch titled net: ll_temac: Avoid ndo_start_xmit returning NETDEV_TX_BUSY to the 5.12-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: net-ll_temac-avoid-ndo_start_xmit-returning-netdev_t.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit eacf94d15e7a94edc571556e08af37ec460c4b0f Author: Esben Haabendal <esben@xxxxxxxxxx> Date: Fri Jun 18 12:52:38 2021 +0200 net: ll_temac: Avoid ndo_start_xmit returning NETDEV_TX_BUSY [ Upstream commit f6396341194234e9b01cd7538bc2c6ac4501ab14 ] As documented in Documentation/networking/driver.rst, the ndo_start_xmit method must not return NETDEV_TX_BUSY under any normal circumstances, and as recommended, we simply stop the tx queue in advance, when there is a risk that the next xmit would cause a NETDEV_TX_BUSY return. Signed-off-by: Esben Haabendal <esben@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c index b105e1d35d15..6bd3a389d389 100644 --- a/drivers/net/ethernet/xilinx/ll_temac_main.c +++ b/drivers/net/ethernet/xilinx/ll_temac_main.c @@ -942,6 +942,11 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev) wmb(); lp->dma_out(lp, TX_TAILDESC_PTR, tail_p); /* DMA start */ + if (temac_check_tx_bd_space(lp, MAX_SKB_FRAGS + 1)) { + netdev_info(ndev, "%s -> netif_stop_queue\n", __func__); + netif_stop_queue(ndev); + } + return NETDEV_TX_OK; }