From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DD21E214204; Mon, 20 Apr 2026 08:26:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776673572; cv=none; b=UyRVQWtdzNTT8VoR37N7hZ9Nbq5Fy8bugEy4TndjtGxkcTW8ARWah1Z6vbOKa87RtbbcWBUku9aJiH3EEtguU+nQfTNTpYgJ0/k9WWatasy5jBMZNXeI98bsF7aRzdYiRAypBapvpCBEbh+MHIngASYBsgr5jh3hhWP6MChUXAU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776673572; c=relaxed/simple; bh=hatqTacSUEjbtlKRMDm5wqYoQ4FvRrpWBAKeel5SoHg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=jptx6k7Ozf9sO0AGgA+FYO3uBkWswXp3QqhDQDAXKLewjtMMajP5IaQ6vS+K+EImAwz7oPIxSZfsM09nHOedLC+mO+lPyZsMz63Ml7/BU674tZhsWqCPu5o/te44saeANMNFVnmxhq/dchT3z/+8E1YuOA1Xf8qgjaCMDAdkXgA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KDEjtn7s; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KDEjtn7s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 130EBC19425; Mon, 20 Apr 2026 08:26:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776673572; bh=hatqTacSUEjbtlKRMDm5wqYoQ4FvRrpWBAKeel5SoHg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=KDEjtn7sF7+FeuU8A2B0AeQPixQcZu4kMVTqOh1v1Dc0N6zlhBYLzS5h4RTC6/YGb mXQC+xMWUKinU10S8ToOJUU19q4RC0FKWR3GJ1M28v6fCz+9KLn3mH1h2KSsH1qEbl DeN88tOQ/hYnbL1e4V5+4TTSFsM0b5unveFIWMR6oxNxZIGTLArVT7N4BF+r5dDWd3 R+ajOnR6750VZF99dyW/cHlJ8bSqO3EiwuArC4FyhNyTf9bV3QYwYwj06mwNpL+Fqz y6y0+nXwF+lniQKHheHmbJ6wGkiiUjtWmADlcxSwIhQkPo+KGdZpX0S02vC+grHm0t 0W2NOkMnYA7XA== Message-ID: <54abe469-dc16-4ed7-a90e-c7ffd419d91e@kernel.org> Date: Mon, 20 Apr 2026 10:26:02 +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 1/1] mptcp: hold subflow request owners when cloning reqsk Content-Language: fr To: Yuan Tan , Kuniyuki Iwashima Cc: Ren Wei , netdev@vger.kernel.org, mptcp@lists.linux.dev, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, ncardwell@google.com, dsahern@kernel.org, martineau@kernel.org, geliang@kernel.org, daniel@iogearbox.net, kafai@fb.com, yifanwucs@gmail.com, tomapufckgml@gmail.com, bird@lzu.edu.cn, caoruide123@gmail.com, enjou1224z@gmail.com References: <86e2514b533bf4d55d4aa2fdbf1404022e8c9430.1776149210.git.caoruide123@gmail.com> <5f06a4e8-0b49-4119-94f9-3a8a1e430e0d@kernel.org> <05a19f8d-360e-41d1-bc8a-0b4caab3d354@gmail.com> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Yuan Tan, On 19/04/2026 11:51, Yuan Tan wrote: > > On 4/16/2026 11:48 AM, Kuniyuki Iwashima wrote: >> On Thu, Apr 16, 2026 at 10:45 AM Matthieu Baerts wrote: >>> Hi Ren, >>> >>> On 15/04/2026 11:31, Ren Wei wrote: >>>> From: Ruide Cao >>>> >>>> TCP request migration clones pending request sockets with >>>> inet_reqsk_clone(). For MPTCP MP_JOIN requests this raw-copies >>>> subflow_req->msk, but the cloned request does not take a new reference. >>>> >>>> Both the original and the cloned request can later drop the same msk in >>>> subflow_req_destructor(), and a migrated request may keep a dangling msk >>>> pointer after the original owner has already been released. >>>> >>>> Add a request_sock clone callback and let MPTCP grab a reference for cloned >>>> subflow requests that carry an msk. This keeps ownership balanced across >>>> both successful migrations and failed clone/insert paths without changing >>>> other protocols. (...) >>>> diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c >>>> index e961936b6be7..140a9e96ad58 100644 >>>> --- a/net/ipv4/inet_connection_sock.c >>>> +++ b/net/ipv4/inet_connection_sock.c >>>> @@ -954,6 +954,9 @@ static struct request_sock *inet_reqsk_clone(struct request_sock *req, >>>> if (sk->sk_protocol == IPPROTO_TCP && tcp_rsk(nreq)->tfo_listener) >>>> rcu_assign_pointer(tcp_sk(nreq->sk)->fastopen_rsk, nreq); >>> (Maybe TCP with fastopen could be this other user to call >>> rcu_assign_pointer()? (net-next material)) >>> >>>> + if (req->rsk_ops->init_clone) >>>> + req->rsk_ops->init_clone(req, nreq); >> I think a simple direct call is better. >> >> #ifdef CONFIG_MPTCP >> if (tcp_rsk(req)->is_mptcp) >> mptcp_reqsk_clone(nreq); >> #endif >> >  Thank you very much for your suggestion. We will use this approach in > the next version of the patch. Would you like us to add your > Suggested-by tag? No need to add a Suggested-by tag: this tag is used when the whole patch idea has been suggested by someone. That's not the case here: we only proposed a small modification in the code, without changing the idea. https://docs.kernel.org/process/submitting-patches.html#using-reported-by-tested-by-reviewed-by-suggested-by-and-fixes Cheers, Matt -- Sponsored by the NGI0 Core fund.