[PATCH net-next 1/5] net: hns3: fix access null pointer issue when set tx-buf-size as 0

[Guangbin Huang]

From: Hao Chen <chenhao288@xxxxxxxxxxxxx>

When set tx-buf-size as 0 by ethtool, hns3_init_tx_spare_buffer()
will return directly and priv->ring->tx_spare->len is uninitialized,
then print function access priv->ring->tx_spare->len will cause
this issue.

When set tx-buf-size as 0 by ethtool, the print function will
print 0 directly and not access priv->ring->tx_spare->len.

Fixes: 2373b35c24ff ("net: hns3: add log for setting tx spare buf size")
Signed-off-by: Hao Chen <chenhao288@xxxxxxxxxxxxx>
Signed-off-by: Guangbin Huang <huangguangbin2@xxxxxxxxxx>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index 1db8a86f046d..6d20974519fe 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -1915,8 +1915,11 @@ static int hns3_set_tunable(struct net_device *netdev,
 			return ret;
 		}
 
-		netdev_info(netdev, "the active tx spare buf size is %u, due to page order\n",
-			    priv->ring->tx_spare->len);
+		if (!priv->ring->tx_spare)
+			netdev_info(netdev, "the active tx spare buf size is 0, disable tx spare buffer\n");
+		else
+			netdev_info(netdev, "the active tx spare buf size is %u, due to page order\n",
+				    priv->ring->tx_spare->len);
 
 		break;
 	default:
-- 
2.33.0