From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 559184C94 for ; Tue, 21 Jun 2022 17:23:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655832219; 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=Z9MjQ0c8ATbIMqXLPsfrTqLkjreDRBVLyKiLVF9YgLh+c2yxFdpGl7+Vw9Smm5eXwnZDty lA1+u2eDjPNr7zhntGTjCBXbUzr2Ufk8JwdZ4+59nJw3GE1wP+ZqexZBPJ+cMtSJ3eBnKm n7mCJ0DSldkGsZj15MbwDqbZLIRd0Cs= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-630-qwFlGVmPPR23vykhMkLA6A-1; Tue, 21 Jun 2022 13:23:38 -0400 X-MC-Unique: qwFlGVmPPR23vykhMkLA6A-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 05778811E80 for ; Tue, 21 Jun 2022 17:23:38 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.193.164]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5D92140CFD0A for ; Tue, 21 Jun 2022 17:23:37 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH v5 mptcp-net 4/6] mptcp: fix shutdown vs fallback race Date: Tue, 21 Jun 2022 19:23:15 +0200 Message-Id: <49c9e2fbafa8345df900ed1cf32c2349f0ca5fb7.1655829222.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 2.84 on 10.11.54.1 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: 8bit Content-Type: text/plain; charset="US-ASCII"; 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 = 0; pr_fallback(msk); - __mptcp_do_fallback(msk); + mptcp_do_fallback(ssk); return false; } 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_sock *msk, MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_INFINITEMAPTX); mptcp_subflow_ctx(ssk)->send_infinite_map = 0; pr_fallback(msk); - __mptcp_do_fallback(msk); + mptcp_do_fallback(ssk); } 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_sock *msk) set_bit(MPTCP_FALLBACK_DONE, &msk->flags); } -static inline void mptcp_do_fallback(struct sock *sk) +static inline void mptcp_do_fallback(struct sock *ssk) { - struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk); - struct mptcp_sock *msk = mptcp_sk(subflow->conn); + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + struct sock *sk = subflow->conn; + struct mptcp_sock *msk; + msk = mptcp_sk(sk); __mptcp_do_fallback(msk); + if (READ_ONCE(msk->snd_data_fin_enable) && !(ssk->sk_shutdown & SEND_SHUTDOWN)) { + gfp_t saved_allocation = ssk->sk_allocation; + + /* we are in a atomic (BH) scope, override ssk default for data + * fin allocation + */ + ssk->sk_allocation = GFP_ATOMIC; + ssk->sk_shutdown |= SEND_SHUTDOWN; + tcp_shutdown(ssk, SEND_SHUTDOWN); + ssk->sk_allocation = saved_allocation; + } } #define pr_fallback(a) pr_debug("%s:fallback to TCP (msk=%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; } - __mptcp_do_fallback(msk); + mptcp_do_fallback(ssk); } skb = skb_peek(&ssk->sk_receive_queue); -- 2.35.3