From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 EC10E4CC278 for ; Mon, 7 Sep 2026 13:46:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788788818; cv=none; b=TAOtEJHRtq4K7u6ZkKEhJsKoVkJnILxIAkFfFyf+ss2LJuVqsYAM8k7DQDzBDKdPra89oOOG7DzU9/dZnmqmB2P1fwuyCM3RfnH0ZZ7o26f5u3O6OTA38XxJNlQ67NXejF9xElOxJMgsh9hBd9mJOemTIt7oKhbQfnyEHBC57Ac= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788788818; c=relaxed/simple; bh=hhUgEHmNufylEgj3ERvWoliIbgY3B0/ay3uKuqek/oE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=oF0ZDXqPTsBQxzSZ7Glw4608nv28tqMZ7LghuNIbbHf8qZDf3F9usKpWlieL0Yg8hAfqZkgKUzLTRzriv/66lbyTuHxrFyBBxq2QEUdcxJauX/l+Qpnqmza9uF0UH+Hd073RykGftFStvQa5/7MDDHslTroN1Mf7CxXDGNw957M= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=f7/oiVku; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="f7/oiVku" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1788788810; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=LbYU6mIGwNAcTeABQ9HUdXCji1Nx0a+jxwN3nhL+4Wc=; b=f7/oiVkufWM4+hAZti2k8GNwIBOicF+WFog/de99l10J1xeA0O9b3Zfe+9ZKOJ7b/YaD8h 9VMH2FgysxngQmL2TbyCKV3xqMBZ4jB1NyUeN2Q1tg5KQ1CAdeOB2g5oVU+zS+VjRDLDCL k/ZIKaydYZyUBGx92DrSExd7poEofoI= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-157-WMGAmzNhMY2XDPXbnjKFzA-1; Mon, 07 Sep 2026 09:46:49 -0400 X-MC-Unique: WMGAmzNhMY2XDPXbnjKFzA-1 X-Mimecast-MFC-AGG-ID: WMGAmzNhMY2XDPXbnjKFzA_1788788808 Received: by mail-ed1-f69.google.com with SMTP id 4fb4d7f45d1cf-6a67fdea041so2889833a12.2 for ; Mon, 07 Sep 2026 06:46:49 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1788788808; x=1789393608; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=LbYU6mIGwNAcTeABQ9HUdXCji1Nx0a+jxwN3nhL+4Wc=; b=TY4wQ/WRiJIJLAX1s0cU/BQhPCtnV88Nzocpdc3ckwgG8kDt9RXhC0FvbgIH869AEK k2Q07WEHqYvQiScTuMEVm+jG5JiyVUmPOkpVebEtxWwB+oxfyRmlMifGyTIKdo8LqJy4 0EHPYslPdXm3/hAM8B54MrNb7PTmiW+VXXVZfZ8HqmYAcCjRUdvZGctVOGZz4gG9IRIV 4pvecnnyOpOnGVoONeYL0hgWy3lKd6GdiD/YGk9ERjs4+thNIAG6CjrRw3jAE3vIBzYp O4O1ezdkrWUzFArrvemEGaauWZnDh5zrsAGHZ6s02fAmeEB6l7IlHtHqNcp9De3HQUNt WGJw== X-Forwarded-Encrypted: i=1; AKwUvBwx0Jdw3K7HIyWzvVD58xJ8ibLe0EnCy8xgsvZg7A4PdMlterxLhtd0Tx3bEAWcos9xw7LWIw==@lists.linux.dev X-Gm-Message-State: AFuF++k3uymH5eZDbnLxqRFu3Coq3k0qq4OUqWkFgkfSKRXyRCuOxGPA IU4d/HaOlVKUBQUWcu1jh36SjqXLLmgCOCSv1LcpuqO+JZwg1Xk0Q+26yBzjfoFgsVnkhisj/QG aFEhRdyuhu5HtXAnbp/xFgwY3nSIW8DUbs95CyoDu3XFYEoM6FnVHaf6D X-Gm-Gg: AYBFou0e4M8fbfRwGnWyHWaZofc9s2SoHqdB8H9xrnEgXeQnQw02FjIH71YdXpzLWVL 8P0iQJmmqhSaWShCMA/MR07Rx5XXWWK/U7JGqXA4e+FlIEUy484mRkYkWTJ7ptlp/V8R4AIJOKc cEFc6DNpGiCnMyNhZWdASAeP+V5OxBTWXw2UId8m8lCcYBCt4Xq2/Usq6Qrr4oMY+R1IMW8bGJa d2SFVx6CL//DWGJtRBF08L8loGTZoUdoUmOKb0OQl5VJ4jjEEc9A3bsyOm7Ov059S0P6PHcNblQ fTVr/FdECxfI/501D4XyyfWj5UzAdx2pTi7REe3a8X7JhtB7zGeGMR8QyfY9fEOEaWGhL4cC6ex zpTH5kibvg4A9o6+FVoczqHHKFl0Hwyi+7JhWYXkwHhsfrQeicF9tUBvknt+V4pht+L0tlb9u+w == X-Received: by 2002:a05:6402:4150:b0:6a7:ee56:615e with SMTP id 4fb4d7f45d1cf-6a7ee56631dmr7067543a12.32.1788788808338; Mon, 07 Sep 2026 06:46:48 -0700 (PDT) X-Received: by 2002:a05:6402:4150:b0:6a7:ee56:615e with SMTP id 4fb4d7f45d1cf-6a7ee56631dmr7067514a12.32.1788788807779; Mon, 07 Sep 2026 06:46:47 -0700 (PDT) Received: from [192.168.188.218] (ip232-47-231-195.pool-bba.aruba.it. [195.231.47.232]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-6a7e6c20c0fsm4583465a12.30.2026.09.07.06.46.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 07 Sep 2026 06:46:46 -0700 (PDT) Message-ID: <14749060-d011-41e7-9a4b-754eb5bd9d5b@redhat.com> Date: Mon, 7 Sep 2026 15:46:45 +0200 Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mptcp-net v3 3/3] tcp: fix data-race in do_recvmmsg / mptcp_recvmsg To: quanyeyang@proton.me, MPTCP Linux Cc: geliang@kernel.org, matttbe@kernel.org References: <20260907-mptcp-snd-una-race-v3-0-65ba0d5f0221@proton.me> <20260907-mptcp-snd-una-race-v3-3-65ba0d5f0221@proton.me> From: Paolo Abeni In-Reply-To: <20260907-mptcp-snd-una-race-v3-3-65ba0d5f0221@proton.me> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: hX6PAi8gSdm_SLAeU3xMGV5nErDXlEepVtWzYYRlAcw_1788788808 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/7/26 12:15 PM, Quanye Yang via B4 Relay wrote: > From: Quanye Yang > > KCSAN reported a data race between do_recvmmsg() and > mptcp_recvmsg() on sk->sk_err. > > do_recvmmsg() calls sock_error() without holding the socket lock. > sock_error() atomically clears sk_err using xchg(), which can race > with the plain read in tcp_recv_should_stop(), even when its caller > holds the socket lock. It looks like the same data-race is present for plain TCP betweem i.e. multiple concurrent recvmmsg() reader? If so, I think this patch could/should go separately directly into the net tree. Also please include the full KCSAN splat. /P