Re: 584c5c422f6c ("x86/ioapic: Support hot-removal of IOAPICs present during boot")

From: Borislav Petkov
Date: Sat Sep 10 2016 - 10:37:47 EST


On Sat, Sep 10, 2016 at 09:11:30PM +0800, Rui Wang wrote:
> Thanks for the analysis. Looks like acpi_gbl_root_node == 0. It is

Is ACPI_HANDLE(root_bus->bridge) == ACPI_ROOT_OBJECT?

Because this is what the code does but I can't see it from the code that
the handle is of type ACPI_ROOT_OBJECT...

> initialized earlier than where we call acpi_ioapic_add().
> start_kernel()
> ->acpi_early_init()
> ->acpi_initialize_subsystem()
> ->acpi_ns_root_initialize()
> -> acpi_gbl_root_node = ...
>
>
> But acpi_gbl_root_node can be 0 if acpi_disabled == 1.
> Do you somehow have acpi turned off (!CONFIG_ACPI or booting with acpi=off)?

Nope.

--
Regards/Gruss,
Boris.

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