On 11/08/13 at 10:14am, Vivek Goyal wrote: > 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 at redhat.com> > > Reported-by: Dave Young <dyoung at redhat.com> > > Tested-by: WANG Chao <chaowang at redhat.com> > > Signed-off-by: Baoquan He <bhe at 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. Hi, Vivek I confirm this patch works for me, even in a nested kexec scenario. Feel free to add these: Bisected-by: WANG Chao <chaowang at redhat.com> Tested-by: WANG Chao <chaowang at redhat.com> Thanks WANG Chao > > 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(); > }