From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757453Ab3KHPOz (ORCPT ); Fri, 8 Nov 2013 10:14:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:12137 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754852Ab3KHPOx (ORCPT ); Fri, 8 Nov 2013 10:14:53 -0500 Date: Fri, 8 Nov 2013 10:14:16 -0500 From: Vivek Goyal To: Baoquan He Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, akpm@linux-foundation.org, davej@fedoraproject.org, rmk+kernel@arm.linux.org.uk, chaowang@redhat.com, mwhitehe@redhat.com, kexec@lists.infradead.org, "Eric W. Biederman" , Robin Holt , Robin Holt Subject: Re: [PATCH] x86: make reboot task only run on the appropriate processor Message-ID: <20131108151416.GA13068@redhat.com> References: <1383642967-12595-1-git-send-email-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1383642967-12595-1-git-send-email-bhe@redhat.com> 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 On Tue, Nov 05, 2013 at 05:16:07PM +0800, Baoquan He wrote: > Currently system always reboot after below message when execute "kexec -e". > > [ 0.572119] smpboot: Booting Node 0, Processors # 1 OK > > In commit 1b3a5d02ee070c8f9943333b9b6370f486601e0f, reboot= handling was > moved to kerne/reboot.c. However, the code to migrate current thread to > reboot cpu was removed. That cause this incorrect kexec behavior. > > Now add that code block back. > > Reported-by: Matthew Whitehead > Reported-by: Dave Young > Tested-by: WANG Chao > Signed-off-by: Baoquan He Hi Bao, This patch fixes the issue for me too. I noticed that we have generic function migrate_to_reboot_cpu() to achieve what we want and rest of the reboot paths are using it. So how about using that function. I wrote the new patch below. It works for me. Can you please give it a try. Thanks Vivek kexec: migrate to reboot cpu Commit 1b3a5d02ee070c8f9943333b9b6370f486601e0f moved reboot= handling to generic code. In the process it also removed the code in native_machine_shutdown() which are moving reboot process to reboot_cpu/cpu0. I guess that thought must have been that all reboot paths are calling migrate_to_reboot_cpu(), so we don't need this special handling. But kexec reboot path (kernel_kexec()) is not calling migrate_to_reboot_cpu() so above change broke kexec. Now reboot can happen on non-boot cpu and when INIT is sent in second kerneo to bring up BP, it brings down the machine. So start calling migrate_to_reboot_cpu() in kexec reboot path to avoid this problem. Reported-by: Matthew Whitehead Reported-by: Dave Young Signed-off-by: Vivek Goyal --- include/linux/reboot.h | 1 + kernel/kexec.c | 1 + kernel/reboot.c | 2 +- 3 files changed, 3 insertions(+), 1 deletion(-) Index: linux-2.6/kernel/reboot.c =================================================================== --- linux-2.6.orig/kernel/reboot.c 2013-10-16 00:30:50.000000000 -0400 +++ linux-2.6/kernel/reboot.c 2013-11-08 21:31:03.379064848 -0500 @@ -104,7 +104,7 @@ int unregister_reboot_notifier(struct no } EXPORT_SYMBOL(unregister_reboot_notifier); -static void migrate_to_reboot_cpu(void) +void migrate_to_reboot_cpu(void) { /* The boot cpu is always logical cpu 0 */ int cpu = reboot_cpu; Index: linux-2.6/include/linux/reboot.h =================================================================== --- linux-2.6.orig/include/linux/reboot.h 2013-11-08 21:33:27.000000000 -0500 +++ linux-2.6/include/linux/reboot.h 2013-11-08 21:34:29.778073522 -0500 @@ -43,6 +43,7 @@ extern int unregister_reboot_notifier(st * Architecture-specific implementations of sys_reboot commands. */ +extern void migrate_to_reboot_cpu(void); extern void machine_restart(char *cmd); extern void machine_halt(void); extern void machine_power_off(void); Index: linux-2.6/kernel/kexec.c =================================================================== --- linux-2.6.orig/kernel/kexec.c 2013-10-16 00:30:50.000000000 -0400 +++ linux-2.6/kernel/kexec.c 2013-11-08 21:34:02.492072375 -0500 @@ -1676,6 +1676,7 @@ int kernel_kexec(void) #endif { kernel_restart_prepare(NULL); + migrate_to_reboot_cpu(); printk(KERN_EMERG "Starting new kernel\n"); machine_shutdown(); }