lkml.org 
[lkml]   [2013]   [Nov]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
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
>
> 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>

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 <mwhitehe@redhat.com>
Reported-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@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();
}

\
 
 \ /
  Last update: 2013-11-08 17:01    [W:0.138 / U:4.416 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site