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Subject[PATCH AUTOSEL 5.4 14/43] drivers/net/wan/lapbether: Set network_header before transmitting
From: Xie He <>

[ Upstream commit 91244d108441013b7367b3b4dcc6869998676473 ]

Set the skb's network_header before it is passed to the underlying
Ethernet device for transmission.

This patch fixes the following issue:

When we use this driver with AF_PACKET sockets, there would be error
messages of:
protocol 0805 is buggy, dev (Ethernet interface name)
printed in the system "dmesg" log.

This is because skbs passed down to the Ethernet device for transmission
don't have their network_header properly set, and the dev_queue_xmit_nit
function in net/core/dev.c complains about this.

Reason of setting the network_header to this place (at the end of the
Ethernet header, and at the beginning of the Ethernet payload):

Because when this driver receives an skb from the Ethernet device, the
network_header is also set at this place.

Cc: Martin Schiller <>
Signed-off-by: Xie He <>
Signed-off-by: David S. Miller <>
Signed-off-by: Sasha Levin <>
drivers/net/wan/lapbether.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/wan/lapbether.c b/drivers/net/wan/lapbether.c
index 373c9ce4010a3..2cff914aada55 100644
--- a/drivers/net/wan/lapbether.c
+++ b/drivers/net/wan/lapbether.c
@@ -210,6 +210,8 @@ static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)

skb->dev = dev = lapbeth->ethdev;

+ skb_reset_network_header(skb);
dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);

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