From owner-freebsd-bugs@FreeBSD.ORG Sun May 6 16:10:11 2012 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id C4473106566C for ; Sun, 6 May 2012 16:10:11 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 9C77B8FC14 for ; Sun, 6 May 2012 16:10:11 +0000 (UTC) Received: from freefall.freebsd.org (localhost [127.0.0.1]) by freefall.freebsd.org (8.14.5/8.14.5) with ESMTP id q46GABFN058737 for ; Sun, 6 May 2012 16:10:11 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.5/8.14.5/Submit) id q46GABut058736; Sun, 6 May 2012 16:10:11 GMT (envelope-from gnats) Resent-Date: Sun, 6 May 2012 16:10:11 GMT Resent-Message-Id: <201205061610.q46GABut058736@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Martin Birgmeier Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 343261065673 for ; Sun, 6 May 2012 16:02:55 +0000 (UTC) (envelope-from nobody@FreeBSD.org) Received: from red.freebsd.org (red.freebsd.org [IPv6:2001:4f8:fff6::22]) by mx1.freebsd.org (Postfix) with ESMTP id 1BF338FC1E for ; Sun, 6 May 2012 16:02:55 +0000 (UTC) Received: from red.freebsd.org (localhost [127.0.0.1]) by red.freebsd.org (8.14.4/8.14.4) with ESMTP id q46G2siZ009029 for ; Sun, 6 May 2012 16:02:54 GMT (envelope-from nobody@red.freebsd.org) Received: (from nobody@localhost) by red.freebsd.org (8.14.4/8.14.4/Submit) id q46G2rOj009028; Sun, 6 May 2012 16:02:54 GMT (envelope-from nobody) Message-Id: <201205061602.q46G2rOj009028@red.freebsd.org> Date: Sun, 6 May 2012 16:02:54 GMT From: Martin Birgmeier To: freebsd-gnats-submit@FreeBSD.org X-Send-Pr-Version: www-3.1 Cc: Subject: kern/167646: IPv6 TCP connection hangs/drops when time/clock on the client is stepped backwards X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 06 May 2012 16:10:12 -0000 >Number: 167646 >Category: kern >Synopsis: IPv6 TCP connection hangs/drops when time/clock on the client is stepped backwards >Confidential: no >Severity: serious >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun May 06 16:10:11 UTC 2012 >Closed-Date: >Last-Modified: >Originator: Martin Birgmeier >Release: 9.0.0, 8.2.0 >Organization: MBi at home >Environment: X server running on: FreeBSD mizar-v1.xyzzy 9.0-RELEASE FreeBSD 9.0-RELEASE #2: Sun Apr 1 19:48:11 CEST 2012 root@mizar.xyzzy:/usr/obj/.../hal/z/SRC/FreeBSD/release/9.0.0/sys/XYZZY_SMP amd64 Client running on: FreeBSD hal.xyzzy 8.2-RELEASE FreeBSD 8.2-RELEASE #4: Sat Aug 27 09:30:11 CEST 2011 root@hal.xyzzy:/z/OBJ/FreeBSD/amd64/RELENG_8_2_0_RELEASE/src/sys/XYZZY_SMP amd64 >Description: I am using xterm over IPv6. The client is 8.2.0 and runs several xterms which connect to the X server on 9.0.0. When a backward time step happens on the client, some of the TCPv6 connections get stuck (the affected xterm windows do not refresh any more) and are ultimately lost. For me, this can happen when ntpd steps the time on the client (it happened twice today, when the first and the third time step occurred): [0]# grep ntp /var/log/messages .. May 6 08:34:56 hal ntpd[965]: time reset -0.354682 s May 6 08:34:56 hal ntpd[965]: kernel time sync status change 2001 May 6 11:58:33 hal ntpd[965]: time reset -0.148885 s May 6 11:58:33 hal ntpd[965]: kernel time sync status change 6001 May 6 12:02:53 hal ntpd[965]: kernel time sync status change 2001 May 6 17:35:29 hal ntpd[965]: time reset -0.274529 s It seems that connections via IPv4 are not affected (not fully sure about that). This is not limited to xterm sessions, see https://bugs.freedesktop.org/show_bug.cgi?id=23325 As can be seen, this problem seems to exist since quite some time. >How-To-Repeat: Establish an IPv6 xterm connection. Step the time on the client (where the xterm runs) backwards. >Fix: >Release-Note: >Audit-Trail: >Unformatted: