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From:   Yonglong Liu <liuyonglong@huawei.com>
To:     <davem@davemloft.net>
CC:     <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linuxarm@huawei.com>, <salil.mehta@huawei.com>,
        <yisen.zhuang@huawei.com>, <shiju.jose@huawei.com>
Subject: [PATCH net 1/6] net: hns: fix KASAN: use-after-free in hns_nic_net_xmit_hw()
Date:   Thu, 4 Apr 2019 16:46:42 +0800
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From: Liubin Shu <shuliubin@huawei.com>

This patch is trying to fix the issue due to:
[27237.844750] BUG: KASAN: use-after-free in hns_nic_net_xmit_hw+0x708/0xa18[hns_enet_drv]

After hnae_queue_xmit() in hns_nic_net_xmit_hw(), can be
interrupted by interruptions, and than call hns_nic_tx_poll_one()
to handle the new packets, and free the skb. So, when turn back to
hns_nic_net_xmit_hw(), calling skb->len will cause use-after-free.

This patch update tx ring statistics in hns_nic_tx_poll_one() to
fix the bug.

Signed-off-by: Liubin Shu <shuliubin@huawei.com>
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Yonglong Liu <liuyonglong@huawei.com>
Signed-off-by: Peng Li <lipeng321@huawei.com>
---
 drivers/net/ethernet/hisilicon/hns/hns_enet.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_enet.c b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
index 60e7d7a..e5a7c07 100644
--- a/drivers/net/ethernet/hisilicon/hns/hns_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_enet.c
@@ -376,8 +376,6 @@ netdev_tx_t hns_nic_net_xmit_hw(struct net_device *ndev,
 	wmb(); /* commit all data before submit */
 	assert(skb->queue_mapping < priv->ae_handle->q_num);
 	hnae_queue_xmit(priv->ae_handle->qs[skb->queue_mapping], buf_num);
-	ring->stats.tx_pkts++;
-	ring->stats.tx_bytes += skb->len;
 
 	return NETDEV_TX_OK;
 
@@ -999,6 +997,9 @@ static int hns_nic_tx_poll_one(struct hns_nic_ring_data *ring_data,
 		/* issue prefetch for next Tx descriptor */
 		prefetch(&ring->desc_cb[ring->next_to_clean]);
 	}
+	/* update tx ring statistics. */
+	ring->stats.tx_pkts += pkts;
+	ring->stats.tx_bytes += bytes;
 
 	NETIF_TX_UNLOCK(ring);
 
-- 
2.8.1