From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756216Ab1AKPrv (ORCPT ); Tue, 11 Jan 2011 10:47:51 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:39110 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755858Ab1AKPrt (ORCPT ); Tue, 11 Jan 2011 10:47:49 -0500 Subject: Re: [tip:x86/urgent] x86: tsc: Prevent delayed init if initial tsc calibration failed From: John Stultz To: linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, tglx@linutronix.de, kas@openvz.org Cc: linux-tip-commits@vger.kernel.org In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Date: Tue, 11 Jan 2011 07:46:46 -0800 Message-ID: <1294760806.2744.8.camel@work-vm> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit X-Content-Scanned: Fidelis XPS MAILER Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-01-11 at 10:51 +0000, tip-bot for Thomas Gleixner wrote: > Commit-ID: 29fe359ca20326e57b25e8545c49ed9ff5e830c7 > Gitweb: http://git.kernel.org/tip/29fe359ca20326e57b25e8545c49ed9ff5e830c7 > Author: Thomas Gleixner > AuthorDate: Tue, 11 Jan 2011 11:40:48 +0100 > Committer: Thomas Gleixner > CommitDate: Tue, 11 Jan 2011 11:48:39 +0100 > > x86: tsc: Prevent delayed init if initial tsc calibration failed > > commit a8760ec (x86: Check tsc available/disabled in the delayed init > function) missed to prevent the setup of the delayed init function in > case the initial tsc calibration failed. This results in the same > divide by zero bug as we have seen without the tsc disabled check. > > Skip the delayed work setup when tsc_khz (the initial calibration > value) is 0. > > Bisected-and-tested-by: Kirill A. Shutemov > Cc: John Stultz > Signed-off-by: Thomas Gleixner Krill: Thanks for reporting and testing! Thomas: Thanks for the fix. I'll see if we can't condense the invalid states a bit more. If tsc_khz=0, we probably should set tsc_disabled. Acked-by: John Stultz > --- > arch/x86/kernel/tsc.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c > index 356a0d4..463901e 100644 > --- a/arch/x86/kernel/tsc.c > +++ b/arch/x86/kernel/tsc.c > @@ -965,7 +965,7 @@ out: > > static int __init init_tsc_clocksource(void) > { > - if (!cpu_has_tsc || tsc_disabled > 0) > + if (!cpu_has_tsc || tsc_disabled > 0 || !tsc_khz) > return 0; > > if (tsc_clocksource_reliable)