On 11/08/13 at 10:14am, Vivek Goyal wrote:
> On Tue, Nov 05, 2013 at 05:16:07PM +0800, Baoquan He 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.
Seems there's something wrong with this function, that error happened
when I executed the 2nd "kexec -e". That means executing "kexec -e" in
kexec-ed kernel.
Tomorrow I will ask people around take more tests. We need set affinity
to test this. E.g always execute :
taskset -c 1 -sh "kexec -e"
>
> 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 <mwhitehe at redhat.com>
> Reported-by: Dave Young <dyoung at redhat.com>
> Signed-off-by: Vivek Goyal <vgoyal at redhat.com>
> ---
> 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();
> }
