From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF92F3EBF28 for ; Tue, 10 Feb 2026 13:21:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770729688; cv=none; b=aEsRx9NIJA5tPsCnMCDyiM+J0Ak9gWHamoBxgZnoZc9DQx5c+cGy4Oyosln9BUMJLz3JWksfiglSWaRM6AJpU0nxDuNo5lAPnQ2t34/LsLSDhKwah41qjYy7bq3dcEWWapPzce/Ru8D6sz6xvMqHF9ah+nEowBmxiUwJJPGE+U0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770729688; c=relaxed/simple; bh=49wWjv80CmOxR9Z6lX1l4jznsqX8vyDBV8vw6cdn++0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PZ/HwOcoxCVMP0aqQAsNjUe+KDJKAoGHwxwdkrBUbUo52lv/GKjAfZVDXz9YZQEloQOD5Qqq7DmuEiAQxQkd41Y11Haa88WIXpiDehbfl+S69frM9tVaaGT+4r1+uio/VMzRGmN/AHqXqwyAbzAaczt3lFd4oIyUjFAWxlNDuJ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nQAFei3i; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="nQAFei3i" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF0CAC116C6; Tue, 10 Feb 2026 13:21:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1770729688; bh=49wWjv80CmOxR9Z6lX1l4jznsqX8vyDBV8vw6cdn++0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nQAFei3i93fgG0Xae0tgFo9nBmHb8HJebSzo+2dtdvTDbyDo6uUoekbSK4bCuHKZj BsI/4Ofr5zNsftESCYHk/NhCszQZBr7RD/KtdwrzBDjw816cIEkbiSRABXzKSn5Wvw 94OXfif+nsb8jHvVWBzBNT/CsJIK9aFLlHxSAzQE= Date: Tue, 10 Feb 2026 14:21:23 +0100 From: Greg Kroah-Hartman To: Eric Dumazet Cc: Ricardo =?iso-8859-1?Q?B=2E_Marli=E8re?= , Hirokazu MORIKAWA , Fernando Fernandez Mancera , davem@davemloft.net, eric.dumazet@gmail.com, horms@kernel.org, kuba@kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzbot+d4dda070f833dc5dc89a@syzkaller.appspotmail.com Subject: Re: [PATCH net] ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv() Message-ID: <2026021011-imperfect-shrewdly-315f@gregkh> References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Tue, Feb 10, 2026 at 01:56:14PM +0100, Eric Dumazet wrote: > On Tue, Feb 10, 2026 at 1:42 PM Ricardo B. Marlière wrote: > > > > On Fri Jan 30, 2026 at 9:00 AM -03, Eric Dumazet wrote: > > > On Fri, Jan 30, 2026 at 5:15 AM Hirokazu MORIKAWA wrote: > > >> > > >> [REGRESSION] ip6_tunnel: IPv4 traffic broken in MAP-E/DS-Lite since > > >> commit df5ffde96693 > > >> > > >> Hi, > > >> I am reporting a regression in the IPv6 tunneling stack (MAP-E and > > >> DS-Lite) introduced in kernel 6.12.67. > > >> > > >> [Description] After upgrading the kernel from 6.12.66 to 6.12.67 in > > >> the OpenWrt snapshot, IPv4 packets can no longer be sent to the > > >> external network via MAP-E or DS-Lite interfaces. > > >> [Environment] > > >> * Hardware: FriendlyElec NanoPi R6C > > >> * OS: OpenWrt snapshot > > >> * Kernel version: 6.12.67 (Broken), 6.12.66 (Working) > > >> * Protocol: MAP-E and DS-Lite > > >> [Culprit] By bisecting/reverting individual commits, I have identified > > >> that the following commit is responsible for this issue: > > >> "ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()" (Link to > > >> the patch: https://lore.kernel.org/netdev/20260107163109.4188620-1-edumazet@google.com/) > > >> Reverting this specific commit on top of kernel 6.12.67 restores > > >> normal connectivity for both MAP-E and DS-Lite. > > >> [Steps to reproduce] > > >> 1. 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 add one. > > > > Perhaps l2_tos_ttl_inherit.sh [1]? I've seen a timeout in this test that > > went away after testing commit 9990ddf47d41 ("net: tunnel: make > > skb_vlan_inet_prepare() return drop reasons") like mentioned here: > > > > https://lore.kernel.org/netdev/DGAR3PO1D33S.1TI7W7U4SPTOG@suse.com/ > > > > It seems that that commit 81c734dae203 ("ip6_tunnel: use > > skb_vlan_inet_prepare() in __ip6_tnl_rcv()") uses the new > > skb_vlan_inet_prepare added in v6.13, which broke 6.12. > > Greg Kroah-Hartman backported my patch to 6.12 LTS, but forgot that a > prior patch > from Menglong Dong inverted the skb_vlan_inet_prepare() return code. > > Greg, can you backport the following to 6.12 LTS ? > > Thanks. > > commit 9990ddf47d4168088e2246c3d418bf526e40830d > Author: Menglong Dong > Date: Wed Oct 9 10:28:21 2024 +0800 > > net: tunnel: make skb_vlan_inet_prepare() return drop reasons > > Make skb_vlan_inet_prepare return the skb drop reasons, which is just > what pskb_may_pull_reason() returns. Meanwhile, adjust all the call of > it. > > Signed-off-by: Menglong Dong > Reviewed-by: Simon Horman > Signed-off-by: David S. Miller Sure, will do after this next round of releases goes out. greg k-h