[PATCH 4/4] net: hns3: double free 'skb'

Subsystems: hisilicon network subsystem 3 driver (hns3), hisilicon network subsystem driver, networking drivers, the rest

STALE2008d

2 messages, 2 authors, 2021-02-03 · open the first message on its own page

[PATCH 4/4] net: hns3: double free 'skb'

From: Wenjia Zhao <hidden>
Date: 2021-02-03 03:20:03

net: hns3: double free 'skb'

The false branch of (tx_ret == NETDEV_TX_OK) free the skb. However, the
kfree_skb(skb) in the out label will be execute when exits the function.
So the skb has a double-free bugs.

Remove the kfree_skb(skb) at line 269

Signed-off-by: Wenjia Zhao <redacted>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c | 1 -
 1 file changed, 1 deletion(-)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index 2622e04..1b926ff 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -266,7 +266,6 @@ static int hns3_lp_run_test(struct net_device *ndev, enum hnae3_loop mode)
 		if (tx_ret == NETDEV_TX_OK) {
 			good_cnt++;
 		} else {
-			kfree_skb(skb);
 			netdev_err(ndev, "hns3_lb_run_test xmit failed: %d\n",
 				   tx_ret);
 		}
-- 
2.7.4

Re: [PATCH 4/4] net: hns3: double free 'skb'

From: Yunsheng Lin <hidden>
Date: 2021-02-03 03:52:23

On 2021/2/3 11:13, Wenjia Zhao wrote:
net: hns3: double free 'skb'

The false branch of (tx_ret == NETDEV_TX_OK) free the skb. However, the
kfree_skb(skb) in the out label will be execute when exits the function.
So the skb has a double-free bugs.

Remove the kfree_skb(skb) at line 269
The freeing is added by the below patch:

commit: 8f9eed1a8791("net: hns3: fix for skb leak when doing selftest")

which is to fix a skb leak problem.

kfree_skb(skb) in the out label corresponds to alloc_skb(),
and kfree_skb(skb) removed in this patch corresponds to
skb_get(skb) before calling hns3_nic_net_xmit() when
hns3_nic_net_xmit() non-NETDEV_TX_OK.

So I do not think there is double free 'skb' here, unless
I miss something here?
quoted hunk
Signed-off-by: Wenjia Zhao <redacted>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c | 1 -
 1 file changed, 1 deletion(-)
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
index 2622e04..1b926ff 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_ethtool.c
@@ -266,7 +266,6 @@ static int hns3_lp_run_test(struct net_device *ndev, enum hnae3_loop mode)
 		if (tx_ret == NETDEV_TX_OK) {
 			good_cnt++;
 		} else {
-			kfree_skb(skb);
 			netdev_err(ndev, "hns3_lb_run_test xmit failed: %d\n",
 				   tx_ret);
 		}

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