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Set up a MAP-E or DS-Lite connection on kernel 6.12.67. >> 2. Attempt to send IPv4 traffic (e.g., ping 8.8.8.8). >> 3. The packets fail to reach the destination. > > Thanks for the report. > > Can you provide detailed instructions ? > > Apparently none of our selftests caught the issue, it would be great to a= dd one. > > I have no idea what MAP-E or DS-Lite are. Hi Eric, I'm troubleshooting a regression on my system after 6.12.63 -> 6.12.67 upgr= ade and my bisecting point to this patch too. My setup is a IP6GRE tunnel over WireGuard, and after the upgrade it can no longer receive any packets over the GRE tunnel. Using tcpdump I can see pac= kets coming in from WireGuard, but they don't end up in the GRE interface. Rever= ting this change, everything works again. I am not a kernel netdev expert, but to me it looks like skb_vlan_inet_prep= are ignores the network_header on the packet completely, which is going to be n= on zero if skb->data !=3D skb->head, given before calling the function, skb_reset_network_header is invoked. And in my case where there is an outer encapsulation layer, skb->data !=3D skb->head would actually happen. Best, Gary