From owner-svn-src-head@freebsd.org Tue Oct 18 02:40:26 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 63AD2C16639; Tue, 18 Oct 2016 02:40:26 +0000 (UTC) (envelope-from hiren@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 358C3FEB; Tue, 18 Oct 2016 02:40:26 +0000 (UTC) (envelope-from hiren@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id u9I2eP0Z052448; Tue, 18 Oct 2016 02:40:25 GMT (envelope-from hiren@FreeBSD.org) Received: (from hiren@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id u9I2ePK9052447; Tue, 18 Oct 2016 02:40:25 GMT (envelope-from hiren@FreeBSD.org) Message-Id: <201610180240.u9I2ePK9052447@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: hiren set sender to hiren@FreeBSD.org using -f From: Hiren Panchasara Date: Tue, 18 Oct 2016 02:40:25 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r307545 - head/sys/netinet X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Oct 2016 02:40:26 -0000 Author: hiren Date: Tue Oct 18 02:40:25 2016 New Revision: 307545 URL: https://svnweb.freebsd.org/changeset/base/307545 Log: Make sure tcp_mss() has the same check as tcp_mss_update() to have t_maxseg set to at least 64. This is still just a coverup to avoid kernel panic and not an actual fix. PR: 213232 Reviewed by: glebius MFC after: 1 week Sponsored by: Limelight Networks Differential Revision: https://reviews.freebsd.org/D8272 Modified: head/sys/netinet/tcp_input.c Modified: head/sys/netinet/tcp_input.c ============================================================================== --- head/sys/netinet/tcp_input.c Tue Oct 18 01:55:07 2016 (r307544) +++ head/sys/netinet/tcp_input.c Tue Oct 18 02:40:25 2016 (r307545) @@ -3758,7 +3758,15 @@ tcp_mss(struct tcpcb *tp, int offer) (void)sbreserve_locked(&so->so_snd, bufsize, so, NULL); } SOCKBUF_UNLOCK(&so->so_snd); - tp->t_maxseg = mss; + /* + * Sanity check: make sure that maxseg will be large + * enough to allow some data on segments even if the + * all the option space is used (40bytes). Otherwise + * funny things may happen in tcp_output. + * + * XXXGL: shouldn't we reserve space for IP/IPv6 options? + */ + tp->t_maxseg = max(mss, 64); SOCKBUF_LOCK(&so->so_rcv); if ((so->so_rcv.sb_hiwat == V_tcp_recvspace) && metrics.rmx_recvpipe)