linux-kernel - Re: [tip:x86/urgent] x86/acpi: Prevent LAPIC id 0xff from being accounted

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Message-ID: <CAE9FiQX6e7zv8C_zewcHiyjAes1CcBaMhSBzjoKQrixsEMAiNg@mail.gmail.com>
Date:   Fri, 7 Oct 2016 22:33:33 -0700
From:   Yinghai Lu <yinghai@...nel.org>
To:     Tang Chen <tangchen@...fujitsu.com>,
        Ingo Molnar <mingo@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, Tony Luck <tony.luck@...el.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>, Yinghai Lu <yinghai@...nel.org>
Cc:     "linux-tip-commits@...r.kernel.org" 
        <linux-tip-commits@...r.kernel.org>
Subject: Re: [tip:x86/urgent] x86/acpi: Prevent LAPIC id 0xff from being accounted

On Fri, Oct 7, 2016 at 10:26 PM, Yinghai Lu <yinghai@...nel.org> wrote:
> On Fri, Oct 7, 2016 at 6:28 AM, tip-bot for Thomas Gleixner
>> diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
>> index 32a7d70..6d35baf 100644
>> --- a/arch/x86/kernel/acpi/boot.c
>> +++ b/arch/x86/kernel/acpi/boot.c
>> @@ -233,6 +233,9 @@ acpi_parse_lapic(struct acpi_subtable_header * header, const unsigned long end)
>>
>>         acpi_table_print_madt_entry(header);
>>
>> +       if (processor->id >= 0xff)
>> +               return -EINVAL;
>> +
>>         /*
>>          * We need to register disabled CPU as well to permit
>>          * counting disabled CPUs. This allows us to size
>
>
> some thing is wrong:
>
> [   71.787437] ACPI: LAPIC (acpi_id[0xff] lapic_id[0xff] disabled)
> [   71.799681] ACPI: Error parsing LAPIC/X2APIC entries
> [   71.809934] ACPI: Invalid BIOS MADT, disabling ACPI
>
> looks like should change
>    return -EINVAL ;
> ==>
>    return 0;

also processor->id is u8,

so the patch should be:

>> +       if (processor->id == 0xff)
>> +               return -EINVAL;
>> +