From owner-svn-src-all@FreeBSD.ORG Fri May 15 09:48:58 2009 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 29768106566C; Fri, 15 May 2009 09:48:58 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from mail.terabit.net.ua (mail.terabit.net.ua [195.137.202.147]) by mx1.freebsd.org (Postfix) with ESMTP id AFD188FC13; Fri, 15 May 2009 09:48:57 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from skuns.zoral.com.ua ([91.193.166.194] helo=mail.zoral.com.ua) by mail.terabit.net.ua with esmtps (TLSv1:AES256-SHA:256) (Exim 4.63 (FreeBSD)) (envelope-from ) id 1M4u2B-0004OF-6p; Fri, 15 May 2009 12:48:55 +0300 Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by mail.zoral.com.ua (8.14.2/8.14.2) with ESMTP id n4F9mq0l050553 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Fri, 15 May 2009 12:48:52 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3) with ESMTP id n4F9mq5i065684; Fri, 15 May 2009 12:48:52 +0300 (EEST) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.3/8.14.3/Submit) id n4F9mq5L065683; Fri, 15 May 2009 12:48:52 +0300 (EEST) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Fri, 15 May 2009 12:48:52 +0300 From: Kostik Belousov To: Peter Holm Message-ID: <20090515094852.GC1927@deviant.kiev.zoral.com.ua> References: <200905141054.n4EAsvp1088977@svn.freebsd.org> <20090515070239.GQ58540@hoeg.nl> <20090515080613.GA27593@x2.osted.lan> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3siQDZowHQqNOShm" Content-Disposition: inline In-Reply-To: <20090515080613.GA27593@x2.osted.lan> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: clamav-milter 0.95.1 at skuns.kiev.zoral.com.ua X-Virus-Status: Clean X-Spam-Status: No, score=-4.4 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 autolearn=ham version=3.2.5 X-Spam-Checker-Version: SpamAssassin 3.2.5 (2008-06-10) on skuns.kiev.zoral.com.ua X-Virus-Scanned: mail.terabit.net.ua 1M4u2B-0004OF-6p ee6a6dc4e3c95b9f9712c95f5ee59bbd X-Terabit: YES Cc: svn-src-head@freebsd.org, Ed Schouten , svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r192094 - head/sys/kern X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 15 May 2009 09:48:58 -0000 --3siQDZowHQqNOShm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, May 15, 2009 at 10:06:13AM +0200, Peter Holm wrote: > On Fri, May 15, 2009 at 09:02:39AM +0200, Ed Schouten wrote: > > Hi Kostik, > >=20 > > * Konstantin Belousov wrote: > > > Log: > > > Do not advance req->oldidx when sysctl_old_user returning an > > > error due to copyout failure or short buffer. > > > =20 > > > The later breaks the usermode iterators of the sysctl results that = pack > > > arbitrary number of variable-sized structures. Iterator expects that > > > kernel filled exactly oldlen bytes, and tries to interpret half-fil= led > > > or garbage structure at the end of the buffer. In particular, > > > kinfo_getfile(3) segfaulted. > > > =20 > > > Reported and tested by: pho > > > MFC after: 3 weeks > >=20 > > Is it possible that this change introduces a regression? Right now > > `pstat -t' gets stuck in an infinite loop. I've added the following > > printf: > >=20 > > | Index: pstat.c > > | =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > | --- pstat.c (revision 192128) > > | +++ pstat.c (working copy) > > | @@ -263,6 +263,7 @@ > > | if (errno !=3D ENOMEM) > > | err(1, "sysctlbyname()"); > > | len *=3D 2; > > | + printf("Going to %zu\n", len); > > | if ((xttys =3D realloc(xttys, len)) =3D=3D NULL) > > | err(1, "realloc()"); > > | } > >=20 > > pstat on -CURRENT prints: > >=20 > > | LINE INQ CAN LIN LOW OUTQ USE LOW COL SESS PGID STA= TE > > | Going to 0 > > | Going to 0 > > | Going to 0 > > | ... > >=20 > > If I use the same patch on RELENG_6, I get the expected result: > >=20 > > | LINE RAW CAN OUT IHIWT ILOWT OHWT LWT COL STATE SESS P= GID DISC > > | Going to 272 > > | Going to 544 > > | Going to 1088 > > | Going to 2176 > > | Going to 4352 > > | Going to 8704 > > | sysmouse 0 0 0 0 0 0 0 0 - 0 = 0 term > > | ... > >=20 > > So the problem is that sysctl overwrites the len argument with 0, even > > if it returns back to userspace with ENOMEM. > >=20 > > I see we have two changes in sysctl. In theory it could also be related > > to jhb@'s changes to sysctl locking, but I suspect it's less likely. > >=20 >=20 > I can confirm that it is r192094 that triggers the loop. Yes, this is what I mean when talked about a breakage. Below is the reversal of r192094 + the change to keep the old, ugly behaviour of sysctl kern.proc.filedesc to return 0 on ENOMEM, but with oldlen chopped at the end of the last completely written struct kern_info instead of the middle of partially-written one. Peter, could you, please, retest ? --3siQDZowHQqNOShm Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkoNOjsACgkQC3+MBN1Mb4h46gCfZws0t7w9YRKFgQtyb8uJYAN2 3NMAniP+hi02OVqqgKivzcPov5V1OSa6 =BBiN -----END PGP SIGNATURE----- --3siQDZowHQqNOShm--