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 6B7F03D9D for ; Wed, 15 Jun 2022 20:28:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1655324906; 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=tJS/33G/jdeIT0WGkXjxwdl7IgG+gCx7SWlT7UoUkzE=; b=Rqq3NXCgzBezbgndYu4VJCw17xctZeEF9W16elCfth/2I8wgs/FEtegbB1NpP4UdRCbjUt s+FeM+uToPRoWV+Xfx0rjqspHT6+Bxt6tZvjp9m+naeNDks1uPmgymDqzhuNktu3uQL1NF Vh2VUD3vRJodqU1ipsNYDbHmXzJMENI= 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-488-py7qMqxaOzKMwtLc8cfr6g-1; Wed, 15 Jun 2022 16:28:25 -0400 X-MC-Unique: py7qMqxaOzKMwtLc8cfr6g-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0B10F299E77E for ; Wed, 15 Jun 2022 20:28:25 +0000 (UTC) Received: from gerbillo.redhat.com (unknown [10.39.193.220]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8DFA040C1288 for ; Wed, 15 Jun 2022 20:28:24 +0000 (UTC) From: Paolo Abeni To: mptcp@lists.linux.dev Subject: [PATCH mptcp-net v2 5/6] mptcp: consistent map handling on failure Date: Wed, 15 Jun 2022 22:28:12 +0200 Message-Id: <7aa8059e8fbbeab845269969ad02784a8c53fb1b.1655324843.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 10.11.54.2 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 When the MPTCP receive path reach a non fatal fall-back condition, e.g. when the MPC sockets must fall-back to TCP, the existing code is a little self-inconsistent: it reports that new data is available - return true - but sets the MPC flag to the opposite value. As the consequence read operations in some exceptional scenario may block unexpectedly. Address the issue setting the correct MPC read status. Additionally avoid some code duplication in the fatal fall-back scenario. Fixes: 9c81be0dbc89 ("mptcp: add MP_FAIL response support") Signed-off-by: Paolo Abeni --- net/mptcp/subflow.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 75fdc6474d0e..bec36e2bcc32 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1246,17 +1246,12 @@ static bool subflow_check_data_avail(struct sock *ssk) subflow->send_mp_fail = 1; if (!READ_ONCE(msk->allow_infinite_fallback)) { - ssk->sk_err = EBADMSG; - tcp_set_state(ssk, TCP_CLOSE); subflow->reset_transient = 0; subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; - tcp_send_active_reset(ssk, GFP_ATOMIC); - while ((skb = skb_peek(&ssk->sk_receive_queue))) - sk_eat_skb(ssk, skb); - } else { - mptcp_subflow_fail(msk, ssk); + goto reset; } - WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_NODATA); + mptcp_subflow_fail(msk, ssk); + WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_DATA_AVAIL); return true; } @@ -1264,10 +1259,14 @@ static bool subflow_check_data_avail(struct sock *ssk) /* fatal protocol error, close the socket. * subflow_error_report() will introduce the appropriate barriers */ - ssk->sk_err = EBADMSG; - tcp_set_state(ssk, TCP_CLOSE); subflow->reset_transient = 0; subflow->reset_reason = MPTCP_RST_EMPTCP; + +reset: + ssk->sk_err = EBADMSG; + tcp_set_state(ssk, TCP_CLOSE); + while ((skb = skb_peek(&ssk->sk_receive_queue))) + sk_eat_skb(ssk, skb); tcp_send_active_reset(ssk, GFP_ATOMIC); WRITE_ONCE(subflow->data_avail, MPTCP_SUBFLOW_NODATA); return false; -- 2.35.3