linux-kernel - Re: Panic starting 6.2.x and later 6.1.x kernels

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Message-ID: <70291f94-1fcf-175c-fc18-e9b656f55af3@amd.com>
Date:   Wed, 29 Mar 2023 14:24:02 -0500
From:   "Limonciello, Mario" <mario.limonciello@....com>
To:     David R <david@...olicited.net>, Borislav Petkov <bp@...en8.de>,
        Gabriel David <ultracoolguy@...root.org>,
        eric.devolder@...cle.com
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Kishon Vijay Abraham I <kvijayab@....com>
Subject: Re: Panic starting 6.2.x and later 6.1.x kernels

On 3/29/2023 14:20, David R wrote:
> On 29/03/2023 20:17, Limonciello, Mario wrote:
>> On 3/29/2023 14:14, David R wrote:
>>> I note that 6.2.8 still has:
>>>
>>> static bool __init acpi_is_processor_usable(u32 lapic_flags)
>>> {
>>>          if (lapic_flags & ACPI_MADT_ENABLED)
>>>                  return true;
>>>
>>>          if (acpi_support_online_capable && (lapic_flags & 
>>> ACPI_MADT_ONLINE_CAPABLE))
>>>                  return true;
>>>
>>>          return false;
>>> }
>>>
>>> The flag getting set to false won't help unless the patch I tried 
>>> previously is applied ?
>>>
>>> diff 
>>> <https://lore.kernel.org/all/20230327191026.3454-2-eric.devolder@oracle.com/#iZ31arch:x86:kernel:acpi:boot.c> --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 1c38174b5f01..7b5b8ed018b0 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -193,7 +193,13 @@ static bool __init acpi_is_processor_usable(u32 lapic_flags)       if (lapic_flags & ACPI_MADT_ENABLED)
>>>           return true;
>>>   - if (acpi_support_online_capable && (lapic_flags & 
>>> ACPI_MADT_ONLINE_CAPABLE)) + /* + * Prior to MADT.revision 5, the 
>>> presence of the Local x2/APIC + * structure _implicitly_ noted a 
>>> possible hotpluggable cpu. + * Starting with MADT.revision 5, the 
>>> Online Capable bit + * _explicitly_ indicates a hotpluggable cpu. + 
>>> */ + if (!acpi_support_online_capable || (lapic_flags & 
>>> ACPI_MADT_ONLINE_CAPABLE))           return true;
>>>         return false;
>>> -- 
>>>
>>
>> You mean specifically this change:
>> https://lore.kernel.org/all/20230327191026.3454-2-eric.devolder@oracle.com/
>>
>> Yes; I suppose that still makes sense.
>>
> Yes, that's the one.
> 
> But the fact that  that one worked own its own implies that my system 
> never had the flag set in the first place?
> 
> David

Right - your BIOS doesn't support MADT revision 5 which was introduced 
as part of ACPI 6.3.

If you haven't already you should add a Tested-by tag for Eric's patch.

I think both mine and his coupled together should cover both of these 
possible areas of breakage.