Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751939Ab2HYKcS (ORCPT ); Sat, 25 Aug 2012 06:32:18 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:63922 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750787Ab2HYKcR (ORCPT ); Sat, 25 Aug 2012 06:32:17 -0400 Date: Sat, 25 Aug 2012 18:33:01 +0800 From: Shawn Guo To: Russell King - ARM Linux Cc: Bill Huang , "'linux-tegra@vger.kernel.org'" , "'linux-kernel@vger.kernel.org'" , "'linux-arm-kernel@lists.infradead.org'" Subject: Re: Shutdown problem in SMP system happened on Tegra20 Message-ID: <20120825103257.GN31998@S2101-09.ap.freescale.net> References: <20120824182133.GB18957@n2100.arm.linux.org.uk> <20120825073624.GI31998@S2101-09.ap.freescale.net> <20120825075221.GH18957@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120825075221.GH18957@n2100.arm.linux.org.uk> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1812 Lines: 43 On Sat, Aug 25, 2012 at 08:52:21AM +0100, Russell King - ARM Linux wrote: > On Sat, Aug 25, 2012 at 03:36:27PM +0800, Shawn Guo wrote: > > On Fri, Aug 24, 2012 at 07:21:33PM +0100, Russell King - ARM Linux wrote: > > > Why not just ensure that CONFIG_PM_SLEEP_SMP is enabled if your platform > > > requires that the lowest CPU number be the CPU dealing with reboot? > > > > I have CONFIG_PM_SLEEP_SMP enabled for imx6q, but still see the imx6q > > restart hook running on cpu1 than cpu0. It seems that > > disable_nonboot_cpus is only called in kernel_power_off but never > > kernel_restart. We should probably patch kernel_restart or > > machine_restart to have disable_nonboot_cpus called? > > Remember that this path gets called from IRQ context which makes calling > functions which sleep very dodgy. I'm so familiar with the code/context. Are you saying disable_nonboot_cpus sleeps and kernel_power_off never gets called from IRQ context? I tested the code change below on kernel_restart with CONFIG_DEBUG_ATOMIC_SLEEP enabled. It fixes imx6q restart issue (with no change on cpu_relax) while no sleep-inside-atomic-section warning is seen. Regards, Shawn diff --git a/kernel/sys.c b/kernel/sys.c index 241507f..0359328 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -373,6 +373,7 @@ void kernel_restart(char *cmd) else printk(KERN_EMERG "Restarting system with command '%s'.\n", cmd); kmsg_dump(KMSG_DUMP_RESTART); + disable_nonboot_cpus(); machine_restart(cmd); } EXPORT_SYMBOL_GPL(kernel_restart); -- 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/