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

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Date:   Sat, 8 Oct 2016 12:08:36 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Yinghai Lu <yinghai@...nel.org>
cc:     Tang Chen <tangchen@...fujitsu.com>,
        Ingo Molnar <mingo@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>, Tony Luck <tony.luck@...el.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        "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, 7 Oct 2016, Yinghai Lu wrote:
> On Fri, Oct 7, 2016 at 10:33 PM, Yinghai Lu <yinghai@...nel.org> wrote:
> > 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;

Indeed.

> >
> > also processor->id is u8,
> >
> > so the patch should be:
> 
> +       if (processor->id == 0xff)
> +               return 0;
> +

Right. Amended the patch and pushed it out.

Thanks for pointing it out,

       tglx