Patch "stmmac: reset last TSO segment size after device open" has been added to the 4.9-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

    stmmac: reset last TSO segment size after device open

to the 4.9-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:
     stmmac-reset-last-tso-segment-size-after-device-open.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Dec 14 11:45:58 CET 2017
From: Lars Persson <lars.persson@axis.com>
Date: Fri, 1 Dec 2017 11:12:44 +0100
Subject: stmmac: reset last TSO segment size after device open

From: Lars Persson <lars.persson@axis.com>


[ Upstream commit 45ab4b13e46325d00f4acdb365d406e941a15f81 ]

The mss variable tracks the last max segment size sent to the TSO
engine. We do not update the hardware as long as we receive skb:s with
the same value in gso_size.

During a network device down/up cycle (mapped to stmmac_release() and
stmmac_open() callbacks) we issue a reset to the hardware and it
forgets the setting for mss. However we did not zero out our mss
variable so the next transmission of a gso packet happens with an
undefined hardware setting.

This triggers a hang in the TSO engine and eventuelly the netdev
watchdog will bark.

Fixes: f748be531d70 ("stmmac: support new GMAC4")
Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |    1 +
 1 file changed, 1 insertion(+)

--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -1795,6 +1795,7 @@ static int stmmac_open(struct net_device
 
 	priv->dma_buf_sz = STMMAC_ALIGN(buf_sz);
 	priv->rx_copybreak = STMMAC_RX_COPYBREAK;
+	priv->mss = 0;
 
 	ret = alloc_dma_desc_resources(priv);
 	if (ret < 0) {


Patches currently in stable-queue which might be from lars.persson@axis.com are

queue-4.9/stmmac-reset-last-tso-segment-size-after-device-open.patch