From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) (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 DAE48371 for ; Tue, 28 Jun 2022 01:02:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1656378172; x=1687914172; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=MRyJYOK7yo5gR8RosTvvsjBH18Xem2fgvLOcM3eLcR8=; b=DwE4f3/ip1oqG4LzW726GXD1R7pEBKB0KD/jytyKIXnlmannXbLiHZtE LJMtX87PHZ5PRnYvjk/51qzg8+mDm200yorCniVgpvEkU9SOcPzMeG5ZQ ucgQ7si6AGP51qj3vPDW53GjlGucwE8JITOTrme29InN4voaqXerY+Ewr IXclVijsGzUSLm+/xMBGOyraQSVSRfSfUGlFZd4rzn3y3WvPNUzLHAmfJ 3Hijd6u0APgtwJaro4mB0gCserU7TJNVYUEqa+MSJrcOZ14Ghjy5+bEeV fg6fL8HSyHC25bgkwMD+NHj5NlynVfEUK8UMfKolSlytH15WWR4XihxsI A==; X-IronPort-AV: E=McAfee;i="6400,9594,10391"; a="270347718" X-IronPort-AV: E=Sophos;i="5.92,227,1650956400"; d="scan'208";a="270347718" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2022 18:02:51 -0700 X-IronPort-AV: E=Sophos;i="5.92,227,1650956400"; d="scan'208";a="692867387" Received: from cgarner-mobl1.amr.corp.intel.com (HELO mjmartin-desk2.intel.com) ([10.251.0.217]) by fmsmga002-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jun 2022 18:02:50 -0700 From: Mat Martineau To: netdev@vger.kernel.org Cc: Paolo Abeni , davem@davemloft.net, kuba@kernel.org, edumazet@google.com, fw@strlen.de, geliang.tang@suse.com, matthieu.baerts@tessares.net, mptcp@lists.linux.dev, Mat Martineau Subject: [PATCH net 5/9] mptcp: consistent map handling on failure Date: Mon, 27 Jun 2022 18:02:39 -0700 Message-Id: <20220628010243.166605-6-mathew.j.martineau@linux.intel.com> X-Mailer: git-send-email 2.37.0 In-Reply-To: <20220628010243.166605-1-mathew.j.martineau@linux.intel.com> References: <20220628010243.166605-1-mathew.j.martineau@linux.intel.com> Precedence: bulk X-Mailing-List: mptcp@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Paolo Abeni 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 Signed-off-by: Mat Martineau --- 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 b34b96fb742f..03862103665d 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1252,17 +1252,12 @@ 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; } @@ -1270,10 +1265,14 @@ 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; -- 2.37.0