This is a note to let you know that I've just added the patch titled

net: avoid skb_warn_bad_offload on IS_ERR

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: net-avoid-skb_warn_bad_offload-on-is_err.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 8d74e9f88d65af8bb2e095aff506aa6eac755ada Mon Sep 17 00:00:00 2001

From: Willem de Bruijn willemb@google.com Date: Tue, 12 Dec 2017 11:39:04 -0500 Subject: net: avoid skb_warn_bad_offload on IS_ERR

From: Willem de Bruijn willemb@google.com

commit 8d74e9f88d65af8bb2e095aff506aa6eac755ada upstream.

skb_warn_bad_offload warns when packets enter the GSO stack that require skb_checksum_help or vice versa. Do not warn on arbitrary bad packets. Packet sockets can craft many. Syzkaller was able to demonstrate another one with eth_type games.

In particular, suppress the warning when segmentation returns an error, which is for reasons other than checksum offload.

See also commit 36c92474498a ("net: WARN if skb_checksum_help() is called on skb requiring segmentation") for context on this warning.

Signed-off-by: Willem de Bruijn willemb@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- net/core/dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/core/dev.c +++ b/net/core/dev.c @@ -2763,7 +2763,7 @@ struct sk_buff *__skb_gso_segment(struct

segs = skb_mac_gso_segment(skb, features);

- if (unlikely(skb_needs_check(skb, tx_path))) + if (unlikely(skb_needs_check(skb, tx_path) && !IS_ERR(segs))) skb_warn_bad_offload(skb);

return segs;

Patches currently in stable-queue which might be from willemb@google.com are

queue-4.9/net-avoid-skb_warn_bad_offload-on-is_err.patch