Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932684AbVINEqm (ORCPT ); Wed, 14 Sep 2005 00:46:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932686AbVINEqm (ORCPT ); Wed, 14 Sep 2005 00:46:42 -0400 Received: from koto.vergenet.net ([210.128.90.7]:424 "EHLO koto.vergenet.net") by vger.kernel.org with ESMTP id S932684AbVINEql (ORCPT ); Wed, 14 Sep 2005 00:46:41 -0400 Date: Wed, 14 Sep 2005 12:13:57 +0900 From: Horms To: Chris Wright Cc: linux-kernel@vger.kernel.org, stable@kernel.org, Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Chuck Wolber , torvalds@osdl.org, akpm@osdl.org, alan@lxorguk.ukuu.org.uk, micha@debian.org Subject: Re: [patch 04/09] x86_64: avoid SMP boot up race Message-ID: <20050914031356.GA19160@verge.net.au> References: <20050608234637.GG13152@shell0.pdx.osdl.net> <20050609000408.GK13152@shell0.pdx.osdl.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20050609000408.GK13152@shell0.pdx.osdl.net> X-Cluestick: seven User-Agent: Mutt/1.5.10i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2460 Lines: 76 Hi, I'm wondering if anyone could comment on if this could be conceived as a security bug. My initial instinct was yes, but on further considertation I can't conceive a way it could be exploited, well not by anyone who couldn't DoS the box in any number of other ways, including shutting it down. On Wed, Jun 08, 2005 at 05:04:08PM -0700, Chris Wright wrote: > Keep interrupts disabled during smp bootup > > This avoids a race that breaks SMP bootup on some machines. > The race is not fully plugged (that is only done with much > more changes in 2.6.12), but should be good enough > for most people. > > Keeping the interrupts disabled here is ok because we > don't rely on the timer interrupt for local APIC > timer setup, but always read the timer registers > directly. > > (originally from Rusty Russell iirc) > > Signed-off-by: ak@suse.de > Signed-off-by: Chris Wright > > diff -u linux/arch/x86_64/kernel/apic.c-o linux/arch/x86_64/kernel/apic.c > --- linux/arch/x86_64/kernel/apic.c-o 2005-05-31 16:40:01.000000000 +0200 > +++ linux/arch/x86_64/kernel/apic.c 2005-05-31 16:44:05.000000000 +0200 > @@ -775,9 +775,7 @@ > > void __init setup_secondary_APIC_clock(void) > { > - local_irq_disable(); /* FIXME: Do we need this? --RR */ > setup_APIC_timer(calibration_result); > - local_irq_enable(); > } > > void __init disable_APIC_timer(void) > diff -u linux/arch/x86_64/kernel/smpboot.c-o linux-2.6.11/arch/x86_64/kernel/smpboot.c > --- linux/arch/x86_64/kernel/smpboot.c-o 2005-03-21 14:04:11.000000000 +0100 > +++ linux/arch/x86_64/kernel/smpboot.c 2005-05-31 16:44:07.000000000 +0200 > @@ -309,8 +309,6 @@ > Dprintk("CALLIN, before setup_local_APIC().\n"); > setup_local_APIC(); > > - local_irq_enable(); > - > /* > * Get our bogomips. > */ > @@ -324,8 +322,6 @@ > */ > smp_store_cpu_info(cpuid); > > - local_irq_disable(); > - > /* > * Allow the master to continue. > */ > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Horms - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/