From owner-freebsd-current@FreeBSD.ORG Sun Mar 2 20:06:59 2008 Return-Path: Delivered-To: current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 4F40D1065671 for ; Sun, 2 Mar 2008 20:06:59 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from relay02.kiev.sovam.com (relay02.kiev.sovam.com [62.64.120.197]) by mx1.freebsd.org (Postfix) with ESMTP id CA1238FC15 for ; Sun, 2 Mar 2008 20:06:58 +0000 (UTC) (envelope-from kostikbel@gmail.com) Received: from [212.82.216.226] (helo=skuns.kiev.zoral.com.ua) by relay02.kiev.sovam.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.67) (envelope-from ) id 1JVuST-0006D0-Bl for current@freebsd.org; Sun, 02 Mar 2008 22:06:57 +0200 Received: from deviant.kiev.zoral.com.ua (root@deviant.kiev.zoral.com.ua [10.1.1.148]) by skuns.kiev.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m22K73Vc035034 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Sun, 2 Mar 2008 22:07:03 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: from deviant.kiev.zoral.com.ua (kostik@localhost [127.0.0.1]) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2) with ESMTP id m22K6mZv055559; Sun, 2 Mar 2008 22:06:48 +0200 (EET) (envelope-from kostikbel@gmail.com) Received: (from kostik@localhost) by deviant.kiev.zoral.com.ua (8.14.2/8.14.2/Submit) id m22K6lUN055558; Sun, 2 Mar 2008 22:06:47 +0200 (EET) (envelope-from kostikbel@gmail.com) X-Authentication-Warning: deviant.kiev.zoral.com.ua: kostik set sender to kostikbel@gmail.com using -f Date: Sun, 2 Mar 2008 22:06:47 +0200 From: Kostik Belousov To: John-Mark Gurney Message-ID: <20080302200647.GQ57756@deviant.kiev.zoral.com.ua> References: <20080302152523.GO57756@deviant.kiev.zoral.com.ua> <20080302195334.GI96595@funkthat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="hMG3mwLWsaCgkvvK" Content-Disposition: inline In-Reply-To: <20080302195334.GI96595@funkthat.com> User-Agent: Mutt/1.4.2.3i X-Virus-Scanned: ClamAV version 0.91.2, clamav-milter version 0.91.2 on 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=3.2.4 X-Spam-Checker-Version: SpamAssassin 3.2.4 (2008-01-01) on skuns.kiev.zoral.com.ua X-Scanner-Signature: 811d4bb63238b2e39a625e79cff8aaca X-DrWeb-checked: yes X-SpamTest-Envelope-From: kostikbel@gmail.com X-SpamTest-Group-ID: 00000000 X-SpamTest-Header: Not Detected X-SpamTest-Info: Profiles 2347 [Mar 2 2008] X-SpamTest-Info: helo_type=3 X-SpamTest-Method: none X-SpamTest-Rate: 0 X-SpamTest-Status: Not detected X-SpamTest-Status-Extended: not_detected X-SpamTest-Version: SMTP-Filter Version 3.0.0 [0278], KAS30/Release Cc: current@freebsd.org Subject: Re: knlist_cleardel() panic X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 02 Mar 2008 20:06:59 -0000 --hMG3mwLWsaCgkvvK Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Mar 02, 2008 at 11:53:34AM -0800, John-Mark Gurney wrote: > Kostik Belousov wrote this message on Sun, Mar 02, 2008 at 17:25 +0200: > > The panic below was already reported, but now I got it on my desktop > > and was able to investigate further. > >=20 > > #5 0xc06daf36 in trap (frame=3D0xe8093b1c) > > at /usr/bsd/src/sys/i386/i386/trap.c:490 > > #6 0xc06c0b4b in calltrap () at /usr/bsd/src/sys/i386/i386/exception.s= :139 > > #7 0xc0493968 in knlist_cleardel (knl=3D0xcabec128, td=3D0x0, islocked= =3D1,=20 > > killkn=3D0) at atomic.h:149 > > #8 0xc04f520c in pipeclose (cpipe=3D0xcabec0b8) > > at /usr/bsd/src/sys/kern/sys_pipe.c:1508 > > #9 0xc04f5320 in pipe_close (fp=3D0xc5ce8630, td=3D0xcac01aa0) > > at /usr/bsd/src/sys/kern/sys_pipe.c:1425 > > #10 0xc0489442 in fdrop (fp=3D0xc5ce8630, td=3D0xcac01aa0) at file.h:297 > > #11 0xc048accf in closef (fp=3D0xc5ce8630, td=3D0xcac01aa0) > > at /usr/bsd/src/sys/kern/kern_descrip.c:1958 > > #12 0xc048b1ff in kern_close (td=3D0xcac01aa0, fd=3D10) > > at /usr/bsd/src/sys/kern/kern_descrip.c:1054 > > #13 0xc048b2da in close (td=3D0xcac01aa0, uap=3D0xe8093cfc) > > at /usr/bsd/src/sys/kern/kern_descrip.c:1006 > > ---Type to continue, or q to quit--- > > #14 0xc06da865 in syscall (frame=3D0xe8093d38) > > at /usr/bsd/src/sys/i386/i386/trap.c:1035 > > #15 0xc06c0bb0 in Xint0x80_syscall () > > at /usr/bsd/src/sys/i386/i386/exception.s:196 > >=20 > > At the frame 8, we have > > (kgdb) p/x *(knl->kl_list->slh_first) > > $9 =3D {kn_link =3D {sle_next =3D 0x0}, kn_selnext =3D {sle_next =3D 0x= 0}, > > kn_knlist =3D 0x0, kn_tqe =3D {tqe_next =3D 0xc58de484, tqe_prev =3D = 0xc5e9ab20}, > > kn_kq =3D 0x0, kn_kevent =3D {ident =3D 0x0, filter =3D 0x0, flags = =3D 0x0, > > fflags =3D 0x0, data =3D 0x0, udata =3D 0x0}, kn_status =3D 0x20, > > kn_sfflags =3D 0x0, kn_sdata =3D 0x0, kn_ptr =3D {p_fp =3D 0x0, p_pro= c =3D 0x0, > > p_aio =3D 0x0, p_lio =3D 0x0}, kn_fop =3D 0x0, kn_hook =3D 0x0} > >=20 > > The knote is KN_MARKER, and the kn_kq is NULL. The result is that KQ_LO= CK > > in the knlist_cleardel()::SLIST_FOREACH_SAFE() loop dereferences NULL a= nd > > panics. > >=20 > > Does the following change makes any sense? >=20 > I thought this was a bug, but upon further examination, there is > something wrong... a KN_MARKER knote should never be on the knlist.. > It is only ever added to kq's even list, never to an object's list... >=20 > If you could walk the knl->kl_list through kn_selnext, and ensure > that the kn w/ kN_MARKER exists would be good... It should be > last one as kn_selnext is NULL... As I shown above, the KN_MARKER was found on the cpipe->pipe_sel.si_note, (kgdb) p cpipe->pipe_sel.si_note $1 =3D {kl_list =3D {slh_first =3D 0xc58df330},=20 kl_lock =3D 0xc0493a20 ,=20 kl_unlock =3D 0xc0493370 ,=20 kl_locked =3D 0xc0493350 , kl_lockarg =3D 0xcabec170 } (kgdb) p/x (knl->kl_list->slh_first) $2 =3D 0xc58df330 (kgdb) p/x *(knl->kl_list->slh_first) $3 =3D {kn_link =3D {sle_next =3D 0x0}, kn_selnext =3D {sle_next =3D 0x0},= =20 kn_knlist =3D 0x0, kn_tqe =3D {tqe_next =3D 0xc58de484, tqe_prev =3D 0xc5= e9ab20},=20 kn_kq =3D 0x0, kn_kevent =3D {ident =3D 0x0, filter =3D 0x0, flags =3D 0x= 0,=20 fflags =3D 0x0, data =3D 0x0, udata =3D 0x0}, kn_status =3D 0x20,=20 kn_sfflags =3D 0x0, kn_sdata =3D 0x0, kn_ptr =3D {p_fp =3D 0x0, p_proc = =3D 0x0,=20 p_aio =3D 0x0, p_lio =3D 0x0}, kn_fop =3D 0x0, kn_hook =3D 0x0} >=20 > I can't think of a way that this can happen, as the only way to get > on the knlist is by calling knlist_add, and it should only ever be > called from f_attach, which is called in one place, and has to have > kn_kq set properly... Are there any custom patches on the system? This is the stock RELENG_7 as of today. --hMG3mwLWsaCgkvvK Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.8 (FreeBSD) iEYEARECAAYFAkfLCNcACgkQC3+MBN1Mb4g2FwCgikWbgwT1LvgAGt3kEiZxtgqq 2TgAoPXUgoqBtJJUeEU3MJy2+Yw83Wdh =+G2X -----END PGP SIGNATURE----- --hMG3mwLWsaCgkvvK--