From: patchwork-bot+netdevbpf@kernel.org
To: Eric Dumazet <edumazet@google.com>
Cc: davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
horms@kernel.org, idosch@nvidia.com, dsahern@kernel.org,
ncardwell@google.com, kuniyu@google.com, netdev@vger.kernel.org,
eric.dumazet@gmail.com,
syzbot+ebdb22d461c904fc3cb2@syzkaller.appspotmail.com,
marcelo.leitner@gmail.com, lucien.xin@gmail.com
Subject: Re: [PATCH net] tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)
Date: Mon, 15 Jun 2026 20:00:06 +0000 [thread overview]
Message-ID: <178155360639.272818.5043247062078863651.git-patchwork-notify@kernel.org> (raw)
In-Reply-To: <20260612162517.83394-1-edumazet@google.com>
Hello:
This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:
On Fri, 12 Jun 2026 16:25:17 +0000 you wrote:
> When MTU is large, ip6_default_advmss() can return IPV6_MAXPLEN (65535).
> This is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535.
>
> However, 0xFFFF is also used as a magic value GSO_BY_FRAGS in the kernel.
> If a TCP packet with gso_size=0xFFFF is passed to skb_segment(), it will
> be mistakenly treated as GSO_BY_FRAGS, leading to a NULL pointer
> dereference because local TCP packets do not use frag_list.
>
> [...]
Here is the summary with links:
- [net] tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)
https://git.kernel.org/netdev/net/c/2bf43d0e2e6a
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
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prev parent reply other threads:[~2026-06-15 20:00 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-12 16:25 [PATCH net] tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) Eric Dumazet
2026-06-13 1:16 ` Kuniyuki Iwashima
2026-06-15 20:00 ` patchwork-bot+netdevbpf [this message]
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