[PATCH] ARM: kexec: offline non panic CPUs on Kdump panic
will.deacon at arm.com
Fri Jul 26 06:49:08 EDT 2013
[Adding Stephen Warren since he has been working in this area]
On Fri, Jul 26, 2013 at 06:41:27AM +0100, vijay.kilari at gmail.com wrote:
> From: Vijaya Kumar K <Vijaya.Kumar at caviumnetworks.com>
> In case of normal kexec kernel load, all cpu's are offlined
> before calling machine_kexec() under kernel_kexec() function.
> But in case crash panic cpus are relaxed in
> machine_crash_nonpanic_core() SMP function but not offlined.
> When crash kernel is loaded with kexec and on panic trigger
> machine_kexec() checks for number of cpus online.
> If more than one cpu is online machine_kexec() fails to load
> with below error
> kexec: error: multiple CPUs still online
> In machine_crash_nonpanic_core() SMP function, offline CPU
> before cpu_relax
> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar at caviumnetworks.com>
> arch/arm/kernel/machine_kexec.c | 1 +
> 1 file changed, 1 insertion(+)
> diff --git a/arch/arm/kernel/machine_kexec.c b/arch/arm/kernel/machine_kexec.c
> index 4fb074c..163b160 100644
> --- a/arch/arm/kernel/machine_kexec.c
> +++ b/arch/arm/kernel/machine_kexec.c
> @@ -73,6 +73,7 @@ void machine_crash_nonpanic_core(void *unused)
> crash_save_cpu(®s, smp_processor_id());
> + set_cpu_online(smp_processor_id(), false);
> while (1)
Ok, I guess this will work since the new kernel is loaded somewhere higher
in memory and the crashed kernel will stick around, so the non-crashing CPUs
can sit around spinning.
More information about the kexec