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Date: Fri, 08 Nov 2013 08:12:00 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Vivek Goyal <vgoyal@redhat.com>, Baoquan He <bhe@redhat.com>
CC: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@redhat.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" <ebiederm@xmission.com>,
        Robin Holt <robinmholt@linux.com>, Robin Holt <robinmholt@gmail.com>
Subject: Re: [PATCH] x86: make reboot task only run on the appropriate processor
References: <1383642967-12595-1-git-send-email-bhe@redhat.com> <20131108151416.GA13068@redhat.com>
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On 11/08/2013 07:14 AM, Vivek Goyal wrote:
> 
> 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
> 

Is this path exercised for the kdump flow?  migrate_to_reboot_cpu() is
unsafe in that case.

> 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();
>  	}
>