Subject: Re: [PATCHv5 net-next 1/2] udp: call udp_encap_enable for v6 sockets when enabling encap

From: Greg Kroah-Hartman <[email-masked]>
Date: Tue, 29 Mar 2022 15:30:40 +0200

On Tue, Mar 29, 2022 at 03:24:49PM +0200, Antonio Quartulli wrote:
> Hi all,
> 
> On 03/02/2021 09:54, Xin Long wrote:
> > When enabling encap for a ipv6 socket without udp_encap_needed_key
> > increased, UDP GRO won't work for v4 mapped v6 address packets as
> > sk will be NULL in udp4_gro_receive().
> > 
> > This patch is to enable it by increasing udp_encap_needed_key for
> > v6 sockets in udp_tunnel_encap_enable(), and correspondingly
> > decrease udp_encap_needed_key in udpv6_destroy_sock().
> > 
> 
> This is a non-negligible issue that other users (in or out of tree) may hit
> as well.
> 
> At OpenVPN we are developing a kernel device driver that has the same
> problem as UDP GRO. So far the only workaround is to let users upgrade to
> v5.12+.
> 
> I would like to propose to take this patch in stable releases.
> Greg, is this an option?
> 
> Commit in the linux kernel is:
> a4a600dd301ccde6ea239804ec1f19364a39d643

What stable tree(s) should this apply to, and where have you tested it?

thanks,

greg k-h