From owner-freebsd-net@freebsd.org Fri Jun 28 13:44:46 2019 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B045E15C1D8B for ; Fri, 28 Jun 2019 13:44:46 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id 400A072559 for ; Fri, 28 Jun 2019 13:44:46 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: by mailman.ysv.freebsd.org (Postfix) id EA33A15C1D8A; Fri, 28 Jun 2019 13:44:45 +0000 (UTC) Delivered-To: net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D72CC15C1D89 for ; Fri, 28 Jun 2019 13:44:45 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.ysv.freebsd.org (mxrelay.ysv.freebsd.org [IPv6:2001:1900:2254:206a::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits) client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.ysv.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 71D6C72553 for ; Fri, 28 Jun 2019 13:44:45 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2001:1900:2254:206a::16:76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.ysv.freebsd.org (Postfix) with ESMTPS id ADAD014126 for ; Fri, 28 Jun 2019 13:44:44 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.118]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id x5SDiiJU041483 for ; Fri, 28 Jun 2019 13:44:44 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id x5SDiifI041482 for net@FreeBSD.org; Fri, 28 Jun 2019 13:44:44 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: net@FreeBSD.org Subject: [Bug 238741] RACK tcpip stack causes connections to hang Date: Fri, 28 Jun 2019 13:44:44 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: kern X-Bugzilla-Version: 12.0-RELEASE X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Only Me X-Bugzilla-Who: adrik@salesmanager.nl X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: net@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 28 Jun 2019 13:44:46 -0000 https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D238741 --- Comment #1 from adrik@salesmanager.nl --- I think the problem might be related to the selected TCP Congestion Control algorithm. If I select Cdg as the TCP Congestion Control algorithm: # kldload cc_cdg # sysctl net.inet.tcp.cc.algorithm=3Dcdg Tcp connections will sometimes hang and finally timeout. When this happens, the socket Send-Q is not empty and will never drain, so = some or all data is never sent. # netstat -6n Active Internet connections Proto Recv-Q Send-Q Local Address Foreign Address (state) tcp6 0 383 2a02:xxxx:yyy:18.56748 2a04:4e42:9::729.443 ESTABLISH= ED The same happens with IPv4 and IPv6 connections. If I change the TCP Congestion Control to any other algorithm, the problem doesn't exist anymore. I did a quick test with NewReno, Cubic, HTcp and Chd as the selected TCP Congestion Control algorithm and all work. --=20 You are receiving this mail because: You are the assignee for the bug.=