From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 EF99D31E106 for ; Mon, 15 Jun 2026 20:00:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781553612; cv=none; b=fJQdcz/qkzx1Y7hfQkUvj2n5V769p17qf9t45vj92F5rgFUOF7tOd7cSZNfUblQCswC1BU/J4hrQmZUoFNhWh+V6TtW8Yw8h7ZL7e+Pe9a5EButwWQ4E1aj1kFuYrLgN861PbL1iKmWlsyZ0Jc9C/d+9ZpFrmhtNK0U1pjKJMrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781553612; c=relaxed/simple; bh=ELHbhRUMqgbc91OYQejyiB48+XwjNjhcJ1wo6GB4MsE=; h=Content-Type:MIME-Version:Subject:From:Message-Id:Date:References: In-Reply-To:To:Cc; b=YanPUWGoRAg7Unpi8jzL9SqjN6vyb2Umz4QB++cbaktNLpHl2BqNV9NcCu8pmSdwTLeLupyZMlQKMMDfdIqozYvp8WGGkJLeEMKZ7qTXvNtA6k0Wm+fPUIfzsNqYdNt57ytgTZMlVv0/eSQJuYr9o7uzAteJ6A8utoU0DW4kykU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AexXUxI/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AexXUxI/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85B931F000E9; Mon, 15 Jun 2026 20:00:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781553611; bh=ZSlPBQgCCyjZetRsD0IOO8PwMyhCB+1BS4cIArHHAco=; h=Subject:From:Date:References:In-Reply-To:To:Cc; b=AexXUxI/JByrDGFTIOmNYislfvY9E4bdOfN5ZVBNPRf4QSkZEOxDsk4MwSqlohf/M pjAadbzYJbq/XKU0h/nJ0c8+WUk2ip8hIT3dL7zzOP1HhKvTDEctkzDaYway8EKyZa ixT31kAObMW5qqePvJLKp5wl8n4SgxFNWtz357cv+bPHEufPCOy8YuLQFeTpYANKPS 9KUthzvmWmPXXBR5wrSjvnTlTQ6AlOLdDGYnFjEZF4rHc9li7JCBfvVg7Yp5peZgkc pCJHpH8ZjTsdWgscQfbuYtcU6U2djXzqcAXo/rlAtkouspHAXuZTeT/OiixT6e8ko5 l0LZJEWZeqHyg== Received: from [10.30.226.235] (localhost [IPv6:::1]) by aws-us-west-2-korg-oddjob-rhel9-1.codeaurora.org (Postfix) with ESMTP id D0A623839A06; Mon, 15 Jun 2026 20:00:07 +0000 (UTC) Content-Type: text/plain; charset="utf-8" Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: Re: [PATCH net] tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) From: patchwork-bot+netdevbpf@kernel.org Message-Id: <178155360639.272818.5043247062078863651.git-patchwork-notify@kernel.org> Date: Mon, 15 Jun 2026 20:00:06 +0000 References: <20260612162517.83394-1-edumazet@google.com> In-Reply-To: <20260612162517.83394-1-edumazet@google.com> To: Eric Dumazet 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 Hello: This patch was applied to netdev/net.git (main) by Jakub Kicinski : 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. https://korg.docs.kernel.org/patchwork/pwbot.html