From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753200Ab2GXCiF (ORCPT ); Mon, 23 Jul 2012 22:38:05 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36582 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752879Ab2GXCiC (ORCPT ); Mon, 23 Jul 2012 22:38:02 -0400 Message-ID: <1343097463.5132.89.camel@deadeye.wl.decadent.org.uk> Subject: Re: [PATCH 00/11] 3.2-stable: Fix for leapsecond caused hrtimer/futex issue From: Ben Hutchings To: John Stultz Cc: Christoph Biedl , stable@vger.kernel.org, Linux Kernel Date: Tue, 24 Jul 2012 03:37:43 +0100 In-Reply-To: <500DAB3F.30606@us.ibm.com> References: <1342508724-14527-1-git-send-email-johnstul@us.ibm.com> <50050FD9.3070403@us.ibm.com> <1342730535@msgid.manchmal.in-ulm.de> <500DAB3F.30606@us.ibm.com> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-9KcT/wAH+sVEHV1OkKJe" X-Mailer: Evolution 3.4.3-1 Mime-Version: 1.0 X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --=-9KcT/wAH+sVEHV1OkKJe Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Mon, 2012-07-23 at 12:51 -0700, John Stultz wrote: > On 07/19/2012 01:48 PM, Christoph Biedl wrote: > > John Stultz wrote... > > > >> Attached is the test case I used to reproduce and test the solution > >> to the hard-hang deadlock. > > I was wondering whether anybody managed to crash a virtualbox guest > > using your program. No avail, using version 4.1.18 on the host and the > > guest kernel running several 3.0.x (x < 38) kernels on both x32 and > > x64, the guest utilies were stopped. Rather a fun fact I guess but I > > wanted to let you know. >=20 > I've been able to crash a kvm guest with an unpatched kernel with my=20 > test. The issue requires that the adding of the hrtimer causes the=20 > clockevent to be reprogrammed. This usually happens if there's no timers= =20 > that expire sooner then the leapsecond timer. So if there are drivers=20 > that set frequent timers, or set timers right before the leapsecond, it= =20 > may be difficult to trigger this issue. >=20 > Lowering HZ or adding more vcpus might help if you really want to be=20 > able to trigger the issue. [...] Your test program also made Linux 3.2.23 (or it may have been .21) lock-up for me in a KVM guest, while 3.2.24-rc1 seemed immune. Ben. --=20 Ben Hutchings If more than one person is responsible for a bug, no one is at fault. --=-9KcT/wAH+sVEHV1OkKJe Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIVAwUAUA4Kd+e/yOyVhhEJAQpsrBAAzefcbUOWvXhMv8OrJICWW3pcpZoxb57k c5l8h6XMyFBfOu6/CPu27aMaezjD87uZHG+BT+L05XkaDeKxtH5ybPI+f1QBUBNH 1R05cye3wySBS4qn2tyqDLOXswOz/rPOnwk4V7Bfu45WiRCvPSMrKeKARUwQBE+8 x9b/kzQjAMxOlH9w4N+o+OpgW1nBaWoGklTOAUIX8mamZNrBwxTw7PNXqMy52hYh phOXnfm3CpJ4jAW66o5wWqU/tY413QIitdxJl46n/28ImkYGLEWtP2/NyaDZx1/T mJFgF2IPBrJM5xK6FNX1ue8j9cffvtCGmfweaT0Mb/luHq+fRN8NzhpkoZx6FEuZ GWzsHAv9Byukjp2uKYmkBFFA0VLgEhiF4czsD/m1FIFrcGIf31MN/X2tSEUje1at 92G+HsUG7WNSbuEKrjrqfAagdfg3Y34XWEMaeQunD5db7F76fJqF2SiBHZcJCEMm elJekckrHUs75bhEug0TUBuEBw1TDVL9rHXT6GMW+A96enfF924uTmm9lqCFUoBk U73sJnD9QzAI0N4G/ya15/cGQZsLNzjppOwaPVtDHnxja9X2D0xPCjxu6j/aKuS3 GzY7d1DjGo2bXUzSgLwmx0SISyFY9/9VeX+QUqGFovtfnt4SLYwExxHK/CSw84CB 9/nNWTHieT8= =Q0Z6 -----END PGP SIGNATURE----- --=-9KcT/wAH+sVEHV1OkKJe--