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 15D861A9F97; Sun, 9 Aug 2026 18:03:39 +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=1786298621; cv=none; b=PQLpWrcUdtssBqcKT9EXwD3SmAEvZKZBk2vo5hYDiUt+7ymfQnOfdaJNK/QcKHzuhGcPjl34AHb1hrRSP8mp6HQDcE1vvD46QPMGK4SQRxPkuh0qQL9m5uTQsco8gOIvAqY//Xpr3mhPbAObOB5DYxdRwR8AUq7kNC2E1hSq64c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786298621; c=relaxed/simple; bh=a/EftZtQS7ASezEqXYlNIwKxlARantvOPOdduisv4+g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=T33mEbkO9b7/8bdCp2v/xcen7XezDllKggp8Y2K16gpg/gWlnmRdFJglUzkPSkwD/6lYbdFevv+C5j5+SgvLRw8z0o80dnYfyf18z7TwCWfhSQJd/3kC46z7DQ5kYedNXDETiVl9rhHO5Vk4g2hd/V78mVebfgG1pwL+7jVN1I4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Hii7hPjp; 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="Hii7hPjp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A0E41F000E9; Sun, 9 Aug 2026 18:03:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786298619; bh=61cs1Wdrbr0AZr0ie9jpePC83AtXC1J7PEfOU0Q2Jnk=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=Hii7hPjpXFAbBtDs0FtOyGAsqGtqI8MkZqXaK/mz0iwM09wQ53RsN93zUfWZLx/Hy JNh89DbHT/P8pTsm/SPs6b3yKML8jE1B1iTCBfWAr6BTIcs4SmgyG+6i10ZokC9mh/ VQgcxjboCkvmWccduJK3csEkmRrxhFtxWYVol0t9VO6m+ofx9pZV3L9rt8vT6wsJVx ytHTowm+za+T1pVEy7cy61kiCyinnMBhfdVvEy9iopIHruJi7ZNZS0NVyv5DYBOGrk 4FgI08bZ07uOd8vQPEx0Z5e7cPn21yzmSmP9/XYYB5SfXe3S7lzZ6aAYJs3wSxdNFB PAseBB/6ivxdQ== Message-ID: <5ac3773c-4a6f-4796-a43f-545c3c42271c@kernel.org> Date: Sun, 9 Aug 2026 20:03:31 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH net v3 2/2] mptcp: fix MP_CAPABLE token migration when cloning reqsk Content-Language: fr To: Ren Wei , netdev@vger.kernel.org, mptcp@lists.linux.dev Cc: martineau@kernel.org, geliang@kernel.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, ncardwell@google.com, kuniyu@google.com, daniel@iogearbox.net, kafai@fb.com, kylebot@openai.com, david.lee@trailofbits.com, vega@nebusec.ai, caoruide123@gmail.com, sashiko-bot@kernel.org References: From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit Hi Ren, Ruide, On 06/08/2026 13:14, Ren Wei wrote: > From: Ruide Cao > > TCP request migration clones pending request sockets with > inet_reqsk_clone(). For MPTCP MP_CAPABLE requests this byte-copies the > token_node hlist state into the clone even though the token table still > names the original request. > > Moving the token only after inet_ehash_insert() succeeds leaves a window > where the cloned request is already globally visible from the ehash but > the token table still points at the original request. Reordering the > move after clone but before ehash exposure closes that window, but > concurrent RX can still race on the old request and observe that the > token was already moved. > > Move MP_CAPABLE token request ownership during MPTCP request cloning > under the token bucket lock. Make mptcp_token_accept() and > mptcp_token_destroy_request() re-check token_node under the same lock and > treat an already moved or removed request as a normal race instead of > warning. > > If the passive MP_CAPABLE socket cannot claim the token, fail > mptcp_sk_clone_init() and let the subflow fall back instead of > installing a socket with mismatched token ownership. Thank you for the new version! I have one major comment, please see below: > Fixes: c905dee62232 ("tcp: Migrate TCP_NEW_SYN_RECV requests at retransmitting SYN+ACKs.") > Cc: stable@vger.kernel.org > Reported-by: Vega > Assisted-by: Codex:gpt-5.4 > Reported-by: Sashiko > Closes: https://sashiko.dev/#/patchset/86e2514b533bf4d55d4aa2fdbf1404022e8c9430.1776149210.git.caoruide123%40gmail.com > Signed-off-by: Ruide Cao > Signed-off-by: Ren Wei > --- > net/mptcp/protocol.c | 12 +++++---- > net/mptcp/protocol.h | 4 ++- > net/mptcp/subflow.c | 2 ++ > net/mptcp/token.c | 61 +++++++++++++++++++++++++++++++++++++----- > net/mptcp/token_test.c | 4 +-- > 5 files changed, 68 insertions(+), 15 deletions(-) > > diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c > index ca644ec53eed..07eaa6858d05 100644 > --- a/net/mptcp/protocol.c > +++ b/net/mptcp/protocol.c > @@ -3608,17 +3608,19 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk, > */ > mptcp_set_state(nsk, TCP_ESTABLISHED); > > + if (!mptcp_token_accept(subflow_req, msk)) { > + mptcp_release_sched(msk); > + inet_csk_prepare_forced_close(nsk); > + tcp_done(nsk); Here, you cannot call tcp_done(nsk): nsk is an MPTCP socket, not a TCP one. You probably want to destroy the msk instead. (In theory, your reproducer launched on a kernel with your patches applied on top of MPTCP's export branch [1] should produce a warning) Apart from that, Clashiko has a few comments. Do you mind checking them and reply to each comment here, before sending a new version, whether you agree/disagree or if it is unclear, please? [1] https://github.com/multipath-tcp/mptcp_net-next/ Cheers, Matt -- Sponsored by the NGI0 Core fund. pw-bot: cr