Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Lars Persson , "David S. Miller" Subject: [PATCH 4.14 16/52] stmmac: reset last TSO segment size after device open Date: Fri, 15 Dec 2017 10:51:53 +0100 Message-Id: <20171215092309.387079635@linuxfoundation.org> In-Reply-To: <20171215092308.500651185@linuxfoundation.org> References: <20171215092308.500651185@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Lars Persson [ 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 Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- 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 @@ -2564,6 +2564,7 @@ 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) {