Messages in this thread | | | Date | Wed, 28 May 2014 22:49:49 -0700 | Subject | kdump kernel with SMP | From | Luong Ngo <> |
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Hello,
I need advises with a problem of kdump kernel in SMP machine. The problem I see is when panic happens, if the panic occurs on core 0, kdump kernel would receive interrups, specifically the sata disk driver works fine, but if panic happens on any other core, kdump kernel seems to not get any interrupt. I add boot parameter to dump local APIC and IO APIC and it looks like all interrupts has the destination is APIC ID 0, which I believe means core 0, while local APIC has a different APIC ID. So I start looking around the kernel and find a function call smp_processor_id() that seems to always return 0 regardless what core is running. This return value ultimately determines the structure cpu_online_map that is returned by apic->target_cpus() inside IO APIC setup code. That is what I believe is happening but not sure if what I understand is right or missing something here? I tried boot parameter max_irqs=0 and interrupts seem to work but I know that would disable SMP and IO APIC. Can kdump kernel be in SMP mode? Why does smp_processor_id returns 0 even though the core that panics is non 0, which cause IO APIC to be programmed with all dest APIC ID to be 0?
Thanks a lot for your help. Regards, Luong
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