From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763904AbXGFSQQ (ORCPT ); Fri, 6 Jul 2007 14:16:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760619AbXGFSQF (ORCPT ); Fri, 6 Jul 2007 14:16:05 -0400 Received: from fmmailgate02.web.de ([217.72.192.227]:51464 "EHLO fmmailgate02.web.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761266AbXGFSQE (ORCPT ); Fri, 6 Jul 2007 14:16:04 -0400 Message-ID: <468E86DF.4050509@web.de> Date: Fri, 06 Jul 2007 20:15:59 +0200 From: Jan Kiszka User-Agent: Thunderbird 2.0.0.4 (Windows/20070604) MIME-Version: 1.0 To: Jason Wessel CC: kgdb-bugreport@lists.sourceforge.net, Andrew Morton , linux-kernel@vger.kernel.org Subject: preemption counter havoc on kgdb-taken faults (was: kgdb Bad IO access) References: <20070628034321.38c9f12b.akpm@linux-foundation.org> <468E4BA5.8010601@imap.cc> <468E8106.8080801@windriver.com> In-Reply-To: <468E8106.8080801@windriver.com> X-Enigmail-Version: 0.95.2 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enigD1A557E5BB67CA9F97FBD950" X-Provags-ID: V01U2FsdGVkX186U/p+EN5f/zEMwCJvs/nOa0mneJAsnM82QpiJ XVBaSRndCK0ShjCNsxKQkvHvqT7vL6YX9F8Hk/v4tPMKZAe+Cd isxrr1KO4= Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enigD1A557E5BB67CA9F97FBD950 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: quoted-printable Jason Wessel wrote: > The only place I could foresee that kgdb could be eating extra cycles i= n=20 > the runtime case is from the die_notifier processing. Any kind of=20 > exception such as a page fault, trap etc... will have a few extra ops=20 > and checks of variables so as to determine if the debugger should take = > the exception. It looks to me like it would even benefit to add the=20 > check at the top of the notify hook for kgdb to exit immediately if the= =20 > debugger is not attached. >=20 > I have contemplated making some changes to KGDB so as to make the=20 > registration to the die_notifier to be dynamic with attaching and=20 > detaching of the debugger. If this is done, I would also make a change= =20 > to allow for the case where the kernel would wait for the debugger to=20 > attach on any fatal fault. At this chance... Reminds me that this old issue still seems to be unsolved in current kgdb: http://www.mail-archive.com/kgdb-bugreport@lists.sourceforge.net/msg00442= =2Ehtml I'm only looking at that spot in kgdb right now and /may/ oversee new border conditions elsewhere. But my feeling is there are none. Jan (looking forward to see kgdb merged) --------------enigD1A557E5BB67CA9F97FBD950 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGjobgniDOoMHTA+kRAgmqAJ0VFklTDNsWYzaYcoYtXPzQE9HsPQCeMt2v Q4BcvTJKQCGVGN17JqiN2GQ= =CwjS -----END PGP SIGNATURE----- --------------enigD1A557E5BB67CA9F97FBD950--