4.9-stable review patch. If anyone has any objections, please let me know.
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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) {