Re: network flow offloading broken in 6.18.45+

[Pablo Neira Ayuso <pablo@netfilter.org>]

Hi,

On Mon, Sep 14, 2026 at 12:13:50AM +0200, Pablo Neira Ayuso wrote:
> On Mon, Sep 14, 2026 at 12:12:16AM +0200, Pablo Neira Ayuso wrote:
> > Hi Hauke,
> > 
> > On Wed, Sep 09, 2026 at 06:29:50PM +0200, Hauke Mehrtens wrote:
> > > Hi,
> > > 
> > > flow offloading is currently broken in Linux 6.18.45.
> > > 
> > > Since the backport of commit b5964aac51e0 ("netfilter: flowtable:
> > > consolidate xmit path") to Linux 6.18.45. This is happening in a router with
> > > traffic from wifi to the Ethernet device when mac80211 returns -EOPNOTSUPP.
> > > 
> > > Upstream fixed it in 871df5007eda ("netfilter: flowtable: bail out if
> > > forward path cannot be discovered") by not offloading the flow at all.
> > > backporting this change looks more complicated.
> > > 
> > > This cam up in a discussion in an OpenWrt PR:
> > > https://github.com/openwrt/openwrt/pull/24800
> > > 
> > > An LLM suggested this change: https://github.com/openwrt/openwrt/pull/24800/changes/394d741e6e76ecd172dbbf1d9ba171e378211734
> > 
> > Patch went away.
> > 
> > > It seams to work, but I do not understand this part of the code god enough
> > > to judge if this is correct.
> > 
> > Could you attach the patch to this email for review?
> 
> I've found it :)
> 
> https://github.com/openwrt/openwrt/commit/d2b53b8043e17087b877bfc2335cbba87dffb4e0

I've proposed the following fix:

https://lore.kernel.org/netfilter-devel/20260914122456.1963453-1-pablo@netfilter.org/