Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Esben Haabendal <esben@geanix.com>
To:     netdev@vger.kernel.org
Cc:     "David S. Miller" <davem@davemloft.net>,
        Michal Simek <michal.simek@xilinx.com>,
        Luis Chamberlain <mcgrof@kernel.org>,
        YueHaibing <yuehaibing@huawei.com>,
        Yang Wei <yang.wei9@zte.com.cn>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3 09/12] net: ll_temac: Fix bug causing buffer descriptor overrun
Date:   Tue, 30 Apr 2019 09:17:56 +0200
Message-Id: <20190430071759.2481-10-esben@geanix.com>
In-Reply-To: <20190430071759.2481-1-esben@geanix.com>
References: <20190429083422.4356-1-esben@geanix.com>
 <20190430071759.2481-1-esben@geanix.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

As we are actually using a BD for both the skb and each frag contained in
it, the oldest TX BD would be overwritten when there was exactly one BD
less than needed.

Signed-off-by: Esben Haabendal <esben@geanix.com>
---
 drivers/net/ethernet/xilinx/ll_temac_main.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/xilinx/ll_temac_main.c b/drivers/net/ethernet/xilinx/ll_temac_main.c
index 7e42746..6837565 100644
--- a/drivers/net/ethernet/xilinx/ll_temac_main.c
+++ b/drivers/net/ethernet/xilinx/ll_temac_main.c
@@ -743,7 +743,7 @@ temac_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 	start_p = lp->tx_bd_p + sizeof(*lp->tx_bd_v) * lp->tx_bd_tail;
 	cur_p = &lp->tx_bd_v[lp->tx_bd_tail];
 
-	if (temac_check_tx_bd_space(lp, num_frag)) {
+	if (temac_check_tx_bd_space(lp, num_frag + 1)) {
 		if (!netif_queue_stopped(ndev))
 			netif_stop_queue(ndev);
 		return NETDEV_TX_BUSY;
-- 
2.4.11