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kexec: migrate to reboot cpu

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Commit 1b3a5d02ee ("reboot: move arch/x86 reboot= handling to generic
kernel") 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.

Bisected by WANG Chao.

Reported-by: Matthew Whitehead <mwhitehe@redhat.com>
Reported-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Tested-by: Baoquan He <bhe@redhat.com>
Tested-by: WANG Chao <chaowang@redhat.com>
Acked-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Vivek Goyal 2013-12-18 17:08:31 -08:00 committed by Linus Torvalds
parent b0031f227e
commit c97102ba96
3 changed files with 3 additions and 1 deletions
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1
include/linux/reboot.h
View file

@ -43,6 +43,7 @@ extern int unregister_reboot_notifier(struct notifier_block *);
* Architecture-specific implementations of sys_reboot commands. * Architecture-specific implementations of sys_reboot commands.
*/ */
extern void migrate_to_reboot_cpu(void);
extern void machine_restart(char *cmd); extern void machine_restart(char *cmd);
extern void machine_halt(void); extern void machine_halt(void);
extern void machine_power_off(void); extern void machine_power_off(void);

1
kernel/kexec.c
View file

@ -1680,6 +1680,7 @@ int kernel_kexec(void)
{ {
kexec_in_progress = true; kexec_in_progress = true;
kernel_restart_prepare(NULL); kernel_restart_prepare(NULL);
migrate_to_reboot_cpu();
printk(KERN_EMERG "Starting new kernel\n"); printk(KERN_EMERG "Starting new kernel\n");
machine_shutdown(); machine_shutdown();
} }

2
kernel/reboot.c
View file

@ -104,7 +104,7 @@ int unregister_reboot_notifier(struct notifier_block *nb)
} }
EXPORT_SYMBOL(unregister_reboot_notifier); 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 */ /* The boot cpu is always logical cpu 0 */
int cpu = reboot_cpu; int cpu = reboot_cpu;