This is a note to let you know that I've just added the patch titled x86/acpi/boot: Correct acpi_is_processor_usable() check to the 6.2-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-acpi-boot-correct-acpi_is_processor_usable-check.patch and it can be found in the queue-6.2 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From fed8d8773b8ea68ad99d9eee8c8343bef9da2c2c Mon Sep 17 00:00:00 2001 From: Eric DeVolder <eric.devolder@xxxxxxxxxx> Date: Mon, 27 Mar 2023 15:10:26 -0400 Subject: x86/acpi/boot: Correct acpi_is_processor_usable() check From: Eric DeVolder <eric.devolder@xxxxxxxxxx> commit fed8d8773b8ea68ad99d9eee8c8343bef9da2c2c upstream. The logic in acpi_is_processor_usable() requires the online capable bit be set for hotpluggable CPUs. The online capable bit has been introduced in ACPI 6.3. However, for ACPI revisions < 6.3 which do not support that bit, CPUs should be reported as usable, not the other way around. Reverse the check. [ bp: Rewrite commit message. ] Fixes: e2869bd7af60 ("x86/acpi/boot: Do not register processors that cannot be onlined for x2APIC") Suggested-by: Miguel Luis <miguel.luis@xxxxxxxxxx> Suggested-by: Boris Ostrovsky <boris.ovstrosky@xxxxxxxxxx> Signed-off-by: Eric DeVolder <eric.devolder@xxxxxxxxxx> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Tested-by: David R <david@xxxxxxxxxxxxxxx> Cc: <stable@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230327191026.3454-2-eric.devolder@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/acpi/boot.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -193,7 +193,8 @@ static bool __init acpi_is_processor_usa if (lapic_flags & ACPI_MADT_ENABLED) return true; - if (acpi_support_online_capable && (lapic_flags & ACPI_MADT_ONLINE_CAPABLE)) + if (!acpi_support_online_capable || + (lapic_flags & ACPI_MADT_ONLINE_CAPABLE)) return true; return false; Patches currently in stable-queue which might be from eric.devolder@xxxxxxxxxx are queue-6.2/x86-acpi-boot-use-fadt-version-to-check-support-for-online-capable.patch queue-6.2/x86-acpi-boot-correct-acpi_is_processor_usable-check.patch