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[139.178.84.19]) by mx.google.com with ESMTPS id l16-20020a056871069000b00101c677fe47si5173217oao.200.2022.06.20.05.30.44 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 20 Jun 2022 05:30:44 -0700 (PDT) Received-SPF: pass (google.com: domain of mptcp+bounces-5712-wpasupplicant.patchew=gmail.com@lists.linux.dev designates 139.178.84.19 as permitted sender) client-ip=139.178.84.19; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=QBJ4Cg7p; spf=pass (google.com: domain of mptcp+bounces-5712-wpasupplicant.patchew=gmail.com@lists.linux.dev designates 139.178.84.19 as permitted sender) smtp.mailfrom="mptcp+bounces-5712-wpasupplicant.patchew=gmail.com@lists.linux.dev"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from smtp.subspace.kernel.org (wormhole.subspace.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by da.mirrors.kernel.org (Postfix) with ESMTPS id A73922E09E8 for ; Mon, 20 Jun 2022 12:30:43 +0000 (UTC) Received: from localhost.localdomain (localhost.localdomain [127.0.0.1]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 439677F6; Mon, 20 Jun 2022 12:30:42 +0000 (UTC) X-Original-To: mptcp@lists.linux.dev 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 AAF6B7E5 for ; Mon, 20 Jun 2022 12:30:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655728238; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=jGdXZqZN+scR9b+LnwI6TAhpQjvehqmnk3OUbGvrK50=; b=QBJ4Cg7puNcoJ8R3Q6rcAbtAJ0ZU0C9ufcSS/cFgtVDXyRijf3OPO9/OUFs3WkrpjmIMge /s6JdA2M0LuFTMkHgkR8C7gBbjOYq0tGwHLdMs2yyj2xQ7qYC9VKewOwsjqS4VgZQKdrUn swq4Z/vJrrzyCpPiZAklKEBf1Vfnyps= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-295-IpZmdh1jOwic3xfINnbP0g-1; Mon, 20 Jun 2022 07:27:17 -0400 X-MC-Unique: IpZmdh1jOwic3xfINnbP0g-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id D59C6299E755 for ; Mon, 20 Jun 2022 11:26:48 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.195.59]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6537D40314B for ; Mon, 20 Jun 2022 11:26:48 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH mptcp-net v4 4/6] mptcp: fix shutdown vs fallback race Date: Mon, 20 Jun 2022 13:26:34 +0200 Message-Id: <49c9e2fbafa8345df900ed1cf32c2349f0ca5fb7.1655723410.git.pabeni@redhat.com> In-Reply-To: References: Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.85 on 10.11.54.10 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=pabeni@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8"; x-default="true" If the MPTCP socket shutdown happens before a fallback to TCP, and all the pending data have been already spooled, we never close the TCP connection. Address the issue explicitly checking for critical condition at fallback time. Signed-off-by: Paolo Abeni --- net/mptcp/options.c | 2 +- net/mptcp/protocol.c | 2 +- net/mptcp/protocol.h | 19 ++++++++++++++++--- net/mptcp/subflow.c | 2 +- 4 files changed, 19 insertions(+), 6 deletions(-) diff --git a/net/mptcp/options.c b/net/mptcp/options.c index 0bfa6662447c..57eab237c837 100644 --- a/net/mptcp/options.c +++ b/net/mptcp/options.c @@ -966,7 +966,7 @@ static bool check_fully_established(struct mptcp_sock *= msk, struct sock *ssk, goto reset; subflow->mp_capable =3D 0; pr_fallback(msk); - __mptcp_do_fallback(msk); + mptcp_do_fallback(ssk); return false; } =20 diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 725fd417ebb1..00ba9c44933a 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1245,7 +1245,7 @@ static void mptcp_update_infinite_map(struct mptcp_so= ck *msk, MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); mptcp_subflow_ctx(ssk)->send_infinite_map =3D 0; pr_fallback(msk); - __mptcp_do_fallback(msk); + mptcp_do_fallback(ssk); } =20 static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 077a717799a0..ad9b02b1b3e6 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -941,12 +941,25 @@ static inline void __mptcp_do_fallback(struct mptcp_s= ock *msk) set_bit(MPTCP_FALLBACK_DONE, &msk->flags); } =20 -static inline void mptcp_do_fallback(struct sock *sk) +static inline void mptcp_do_fallback(struct sock *ssk) { - struct mptcp_subflow_context *subflow =3D mptcp_subflow_ctx(sk); - struct mptcp_sock *msk =3D mptcp_sk(subflow->conn); + struct mptcp_subflow_context *subflow =3D mptcp_subflow_ctx(ssk); + struct sock *sk =3D subflow->conn; + struct mptcp_sock *msk; =20 + msk =3D mptcp_sk(sk); __mptcp_do_fallback(msk); + if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUT= DOWN)) { + gfp_t saved_allocation =3D ssk->sk_allocation; + + /* we are in a atomic (BH) scope, override ssk default for data + * fin allocation + */ + ssk->sk_allocation =3D GFP_ATOMIC; + ssk->sk_shutdown |=3D SEND_SHUTDOWN; + tcp_shutdown(ssk, SEND_SHUTDOWN); + ssk->sk_allocation =3D saved_allocation; + } } =20 #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=3D%p)", __func__,= a) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 238330da3f1f..77fccc49d05c 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1279,7 +1279,7 @@ static bool subflow_check_data_avail(struct sock *ssk) return false; } =20 - __mptcp_do_fallback(msk); + mptcp_do_fallback(ssk); } =20 skb =3D skb_peek(&ssk->sk_receive_queue); --=20 2.35.3