Extending commit aa06e20f1be6 ("x86/ACPI: Don't add CPUs that are not online capable") to include acpi_parse_x2apic as well. There is a check for invalid apicid; however, there are BIOS FW with madt version >= 5 support that do not bother setting apic id to an invalid value since they assume the OS will check the enabled and online capable flags. Signed-off-by: James Puthukattukaran<james.puthukattukaran@xxxxxxxxxx> Reported-by: Benjamin Fuller<ben.fuller@xxxxxxxxxx> v2 : use 'enabled' local variable. Also fix checkpatch.pl catches v3 : updates as per Rafael's comments --- arch/x86/kernel/acpi/boot.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 907cc98b1938..cf2509f9de31 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -208,7 +208,15 @@ acpi_parse_x2apic(union acpi_subtable_headers *header, const unsigned long end) apic_id = processor->local_apic_id; enabled = processor->lapic_flags & ACPI_MADT_ENABLED; - /* Ignore invalid ID */ + /* don't register processors that can not be onlined */ + if (!enabled && acpi_support_online_capable && + !(processor->lapic_flags & ACPI_MADT_ONLINE_CAPABLE)) + return 0; + + /* + * for systems older than madt version 5 (does not have + * ACPI_MADT_ONLINE_CAPABLE defined); ignore invalid ID + */ if (apic_id == 0xffffffff) return 0; -- 2.31.1