Re: [PATCH] x86/mce: Keep quiet in case of broadcasted mce after system panic
From: Borislav Petkov
Date: Fri Feb 17 2017 - 04:08:18 EST
On Fri, Feb 17, 2017 at 09:53:21AM +0800, Xunlei Pang wrote:
> It changes the value of cpu_online_mask/etc which will cause confusion to vmcore analysis.
Then export the crashing_cpu variable, initialize it to something
invalid in the first kernel, -1 for example, and test it in the #MC
handlier like this:
int cpu;
...
cpu = smp_processor_id();
if (cpu_is_offline(cpu) ||
((crashing_cpu != -1) && (crashing_cpu != cpu)) {
u64 mcgstatus;
mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
if (mcgstatus & MCG_STATUS_RIPV) {
mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
return;
}
}
> Moreover, for the code(see comment inlined)
>
> if (cpu_is_offline(smp_processor_id())) {
> u64 mcgstatus;
>
> mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
> if (mcgstatus & MCG_STATUS_RIPV) { // This condition may be not true, the mce triggered on kdump cpu
> // doesn't need to have this bit set for the other cpus remain in 1st kernel.
Is this on kvm or on a real hardware? Because for kvm I don't care. And
don't say "theoretically".
--
Regards/Gruss,
Boris.
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