This is a note to let you know that I've just added the patch titled net: hsr: Reset MAC header for Tx path to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-hsr-reset-mac-header-for-tx-path.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 9d6803921a16f4d768dc41a75375629828f4d91e Mon Sep 17 00:00:00 2001 From: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx> Date: Tue, 6 Apr 2021 09:35:09 +0200 Subject: net: hsr: Reset MAC header for Tx path From: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx> commit 9d6803921a16f4d768dc41a75375629828f4d91e upstream. Reset MAC header in HSR Tx path. This is needed, because direct packet transmission, e.g. by specifying PACKET_QDISC_BYPASS does not reset the MAC header. This has been observed using the following setup: |$ ip link add name hsr0 type hsr slave1 lan0 slave2 lan1 supervision 45 version 1 |$ ifconfig hsr0 up |$ ./test hsr0 The test binary is using mmap'ed sockets and is specifying the PACKET_QDISC_BYPASS socket option. This patch resolves the following warning on a non-patched kernel: |[ 112.725394] ------------[ cut here ]------------ |[ 112.731418] WARNING: CPU: 1 PID: 257 at net/hsr/hsr_forward.c:560 hsr_forward_skb+0x484/0x568 |[ 112.739962] net/hsr/hsr_forward.c:560: Malformed frame (port_src hsr0) The warning can be safely removed, because the other call sites of hsr_forward_skb() make sure that the skb is prepared correctly. Fixes: d346a3fae3ff ("packet: introduce PACKET_QDISC_BYPASS socket option") Signed-off-by: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/hsr/hsr_device.c | 1 + net/hsr/hsr_forward.c | 6 ------ 2 files changed, 1 insertion(+), 6 deletions(-) --- a/net/hsr/hsr_device.c +++ b/net/hsr/hsr_device.c @@ -229,6 +229,7 @@ static int hsr_dev_xmit(struct sk_buff * master = hsr_port_get_hsr(hsr, HSR_PT_MASTER); if (master) { skb->dev = master->dev; + skb_reset_mac_header(skb); hsr_forward_skb(skb, master); } else { atomic_long_inc(&dev->tx_dropped); --- a/net/hsr/hsr_forward.c +++ b/net/hsr/hsr_forward.c @@ -349,12 +349,6 @@ void hsr_forward_skb(struct sk_buff *skb { struct hsr_frame_info frame; - if (skb_mac_header(skb) != skb->data) { - WARN_ONCE(1, "%s:%d: Malformed frame (port_src %s)\n", - __FILE__, __LINE__, port->dev->name); - goto out_drop; - } - if (hsr_fill_frame_info(&frame, skb, port) < 0) goto out_drop; hsr_register_frame_in(frame.node_src, port, frame.sequence_nr); Patches currently in stable-queue which might be from kurt@xxxxxxxxxxxxx are queue-5.4/net-hsr-reset-mac-header-for-tx-path.patch