Bug#1108860: linux-image-6.1.0-34-amd64: Wireguard fragmentation fails with VXLAN since kernel 6.1.0-34, causing network timeouts

[Salvatore Bonaccorso <carnil@debian.org>]

Control: tags -1 - moreinfo
Control: tags -1 + confirmed

Hi Charles,

On Sun, Jul 13, 2025 at 08:41:39AM +0200, rough.rock3059@datachamp.fr wrote:
> Hi Salvatore,
> 
> Thank you for your guidance and for pointing out the relevant commit.
> 
> I have tested, checking out from tag 6.1.134:
> - With the revert of commit b88786ea2c8f ("tunnels: Accept PACKET_HOST in skb_tunnel_check_pmtu()"): the issue does not appear and everything works as expected
> - With the commit included (no revert), the issue reappears exactly as before.
> 
> This confirms that the regression is directly linked to this commit.
> 
> Is there anything else I can do or provide to help with the resolution?

Thanks a lot that is great news, so we have isolated the regression
commit already. I will try to assemble a regression report upstream
soon (after checking if it is already known, hopefully not missing a
report) and keep you in the loop.

Regards,
Salvatore