From: Yaroslav Dudkov <aroslavdudkov622@gmail.com>
To: Ido Schimmel <idosch@nvidia.com>
Cc: netdev@vger.kernel.org, davem@davemloft.net, kuba@kernel.org,
pabeni@redhat.com, edumazet@google.com, dsahern@kernel.org,
horms@kernel.org, aconole@redhat.com, sbrivio@redhat.com,
gnault@redhat.com, laikabcprice@gmail.com,
rough.rock3059@datachamp.fr, stable@vger.kernel.org,
Yaroslav Dudkov <aroslavdudkov622@gmail.com>
Subject: Re: [PATCH net] tunnels: Drop stale dst when building an ICMP error for PMTUD
Date: Wed, 2 Sep 2026 19:50:10 +0000 [thread overview]
Message-ID: <20260902195012.265628-1-aroslavdudkov622@gmail.com> (raw)
In-Reply-To: <20260902190112.4126199-1-idosch@nvidia.com>
On Wed, Sep 02, 2026 at 07:01:12PM +0000, Ido Schimmel wrote:
> Fix this by making sure that the ICMP error packet does not have a valid
> dst entry, thereby forcing the IP layer to perform a route lookup.
Tested on net with this patch applied:
- pmtu.sh: all 16 bridged and all 16 OVS subtests pass, both with and
without br_netfilter loaded. Without the patch, loading br_netfilter
makes all 16 bridged subtests fail (the reply gets delivered and exits
with the old -w 1 failure).
- The forwarded-sender reproducer from my earlier mail goes from
10 tx / 0 rx / no errors to 10 tx / 8 rx / +1 error, the error being
"From 192.168.4.1 icmp_seq=1 Frag needed and DF set (mtu = 3950)" --
the tunnel's PTB reaching the sender.
Tested-by: Yaroslav Dudkov <aroslavdudkov622@gmail.com>
next prev parent reply other threads:[~2026-09-02 19:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-02 19:01 [PATCH net] tunnels: Drop stale dst when building an ICMP error for PMTUD Ido Schimmel
2026-09-02 19:50 ` Yaroslav Dudkov [this message]
2026-09-02 20:23 ` David Ahern
2026-09-03 7:55 ` Stefano Brivio
2026-09-03 9:28 ` Guillaume Nault
2026-09-04 0:50 ` patchwork-bot+netdevbpf
2026-09-04 17:09 ` Aaron Conole
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