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SubjectRe: [PATCH] x86: make reboot task only run on the appropriate processor
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
>

So is it same problem were we reboot on non-boot cpu and sending INIT
to boot cpu in second kernel brings down the machine?

I think for x86, it makes sense to reboot on boot cpu.

Thanks
Vivek

> 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 <mwhitehe@redhat.com>
> Reported-by: Dave Young <dyoung@redhat.com>
> Tested-by: WANG Chao <chaowang@redhat.com>
> Signed-off-by: Baoquan He <bhe@redhat.com>
> ---
> arch/x86/kernel/reboot.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/arch/x86/kernel/reboot.c b/arch/x86/kernel/reboot.c
> index 7e920bf..3049de9 100644
> --- a/arch/x86/kernel/reboot.c
> +++ b/arch/x86/kernel/reboot.c
> @@ -551,6 +551,21 @@ void native_machine_shutdown(void)
> {
> /* Stop the cpus and apics */
> #ifdef CONFIG_SMP
> + /* The boot cpu is always logical cpu 0 */
> + int reboot_cpu_id = 0;
> +
> + /* See if there has been given a command line override */
> + if ((reboot_cpu != -1) && (reboot_cpu < nr_cpu_ids) &&
> + cpu_online(reboot_cpu))
> + reboot_cpu_id = reboot_cpu;
> +
> + /* Make certain the cpu I'm about to reboot on is online */
> + if (!cpu_online(reboot_cpu_id))
> + reboot_cpu_id = smp_processor_id();
> +
> + /* Make certain I only run on the appropriate processor */
> + set_cpus_allowed_ptr(current, cpumask_of(reboot_cpu_id));
> +
> /*
> * Stop all of the others. Also disable the local irq to
> * not receive the per-cpu timer interrupt which may trigger
> --
> 1.8.3.1


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