Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759198AbXI1OMK (ORCPT ); Fri, 28 Sep 2007 10:12:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755484AbXI1OLq (ORCPT ); Fri, 28 Sep 2007 10:11:46 -0400 Received: from rtr.ca ([76.10.145.34]:3472 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755332AbXI1OLp (ORCPT ); Fri, 28 Sep 2007 10:11:45 -0400 Message-ID: <46FD0BA2.6030600@rtr.ca> Date: Fri, 28 Sep 2007 10:11:46 -0400 From: Mark Lord User-Agent: Thunderbird 2.0.0.6 (X11/20070728) MIME-Version: 1.0 To: "Rafael J. Wysocki" Cc: Len Brown , Linux Kernel , simon.derr@bull.net Subject: Re: [PATCH] disable non-boot CPUs before poweroff References: <46FC20B7.4000606@rtr.ca> <200709281455.29069.rjw@sisk.pl> <46FD001A.3070309@rtr.ca> <200709281544.30497.rjw@sisk.pl> <46FD05B8.2040302@rtr.ca> <46FD0724.5060009@rtr.ca> In-Reply-To: <46FD0724.5060009@rtr.ca> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1480 Lines: 44 Mark Lord wrote: > > We need to disable all CPUs other than the boot CPU (usually 0) > before attempting to power-off modern SMP machines. > This seems to fix the hang-on-poweroff issue > that one of my SMP boxes exhibits. More testing required. > > Signed-off-by: Mark Lord > --- > > --- linux/kernel/sys.c.orig 2007-09-13 09:49:11.000000000 -0400 > +++ linux/kernel/sys.c 2007-09-28 09:48:54.000000000 -0400 > @@ -32,6 +32,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -879,6 +880,7 @@ > if (pm_power_off_prepare) > pm_power_off_prepare(); > sysdev_shutdown(); > + disable_nonboot_cpus(); > printk(KERN_EMERG "Power down.\n"); > machine_power_off(); > } Okay, verified now. Prior to this patch, *both* CPUs were still up and running when machine_power_off() got called, and there was no guarantee that CPU0 was the one calling machine_power_off(). BUG. The above patch guarantees that only the single boot CPU is running and calling machine_power_off(). Hopefully this buries the SMP-power-off bogeyman for good! Cheers - 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/