| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 012/144] kexec: migrate to reboot cpu | Date | Mon, 6 Jan 2014 14:36:13 -0800 |
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3.12-stable review patch. If anyone has any objections, please let me know.
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From: Vivek Goyal <vgoyal@redhat.com>
commit c97102ba96324da330078ad8619ba4dfe840dbe3 upstream.
Commit 1b3a5d02ee07 ("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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- include/linux/reboot.h | 1 + kernel/kexec.c | 1 + kernel/reboot.c | 2 +- 3 files changed, 3 insertions(+), 1 deletion(-)
--- a/include/linux/reboot.h +++ b/include/linux/reboot.h @@ -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); --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -1680,6 +1680,7 @@ int kernel_kexec(void) { kexec_in_progress = true; kernel_restart_prepare(NULL); + migrate_to_reboot_cpu(); printk(KERN_EMERG "Starting new kernel\n"); machine_shutdown(); } --- a/kernel/reboot.c +++ b/kernel/reboot.c @@ -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;
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