From owner-freebsd-stable@FreeBSD.ORG Fri Jun 30 12:06:14 2006 Return-Path: X-Original-To: freebsd-stable@freebsd.org Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2C5F616A415 for ; Fri, 30 Jun 2006 12:06:14 +0000 (UTC) (envelope-from sthalik@tehran.lain.pl) Received: from mail.in5.pl (rollercoaster.insane.pl [213.251.173.13]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7A29043D45 for ; Fri, 30 Jun 2006 12:06:12 +0000 (GMT) (envelope-from sthalik@tehran.lain.pl) Received: from tehran.lain.pl ([85.221.230.102] helo=tehran.local ident=mailnull) from mailnull by mail.in5.pl with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (envelope-from ) id 1FwHlD-0003u3-Je for freebsd-stable@freebsd.org; Fri, 30 Jun 2006 14:06:11 +0200 Received: from sthalik by tehran.local with local (Exim 4.62 (FreeBSD)) (envelope-from ) id 1FwHnA-0000cc-8i for freebsd-stable@freebsd.org; Fri, 30 Jun 2006 14:08:12 +0200 Date: Fri, 30 Jun 2006 14:08:12 +0200 From: Stanislaw Halik To: freebsd-stable@freebsd.org Message-ID: <20060630120812.GA2380@tehran.lain.pl> Mail-Followup-To: freebsd-stable@freebsd.org References: <20060627045310.GA6324@tehran.lain.pl> <20060627140946.J273@fledge.watson.org> <20060627134134.GA23337@tehran.lain.pl> <20060628101405.I50845@fledge.watson.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="AqsLC8rIMeq19msA" Content-Disposition: inline In-Reply-To: <20060628101405.I50845@fledge.watson.org> X-PGP-Key: http://tehran.lain.pl/public.key User-Agent: Mutt/1.5.11 Subject: Re: trap 12: supervisor write, page not present on 6.1-STABLE Tue May 16 2006 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 30 Jun 2006 12:06:14 -0000 --AqsLC8rIMeq19msA Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jun 28, 2006, Robert Watson wrote: >>>> 6.1-STABLE crashed on me. I'm providing a backtrace. Could any of you, >>>> experienced people, suggest me if it's a hardware problem or is it an >>>> error inside the OS? >>> This is a known bug in the TCP code; a large set of outstanding changes= =20 >>> is present in 7.x that will fix the problem when merged. However, I=20 >>> recently had push-back on merging the larger batch of changes, so am=20 >>> looking at merging a workaround that will also correct the problem=20 >>> without the larger set of architectural changes. I hope to have a chan= ce=20 >>> to look at that in detail this weekend. >> I'm glad to know that it isn't either unknown or hardware-related. Thank= =20 >> you for your prompt reply! > Per my earlier e-mail, I had hoped to merge a larger set of changes from= =20 > HEAD that resolve the underlying problem here (that inpcb's can be detach= ed=20 > from a socket while the socket is still in use), but right now I'm=20 > deferring merging those changes as they are somewhat risky (as they are= =20 > large). Instead, I've produced a candidate work-around patch, now attach= ed=20 > to kern/97095. This does not fix the underlying problem, but seeks to=20 > narrow the window for the race to be exercised by avoiding caching a=20 > volatile pointer across user memory copying, which under load can result = in=20 > blocking I/O. I would be quite interested in knowing if this resolves th= e=20 > problem in practice -- if so, it's a definite short-term merge candidate = to=20 > reduce the symptoms of this problem until the proper fix can be merged. Unfortunately, it still happens to crash in the same code path: (kgdb) up 7 #7 0xc058e947 in ip_ctloutput (so=3D0x0, sopt=3D0xd67f2c80) at /usr/src/sys/netinet/ip_output.c:1216 1216 inp->inp_ip_tos =3D optval; (kgdb) l /usr/src/sys/netinet/ip_output.c:1216 1211 break; 1212 1213 inp =3D sotoinpcb(so); 1214 switch (sopt->sopt_name) { 1215 case IP_TOS: 1216 inp->inp_ip_tos =3D optval; 1217 break; 1218 1219 case IP_TTL: 1220 inp->inp_ip_ttl =3D optval; (kgdb) p inp $1 =3D (struct inpcb *) 0x0 I'll be happy to test any other patches when they're available. --AqsLC8rIMeq19msA Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (FreeBSD) iD8DBQFEpRQradU+vjT62TERAjJrAJ0bWpv8wC6K2BAelp8POEoXqYmgigCfbJUG aQLckZG3f03/qf3S8mXQsAw= =9bjz -----END PGP SIGNATURE----- --AqsLC8rIMeq19msA--