linux-kernel - Re: [PATCH v2] x86/mce: Don't participate in rendezvous process once nmi_shootdown

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Message-ID: <20170221172703.sy7d2mexo4naxj52@pd.tnic>
Date:   Tue, 21 Feb 2017 18:27:03 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     xlpang@...hat.com
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        kexec@...ts.infradead.org, Tony Luck <tony.luck@...el.com>,
        Ingo Molnar <mingo@...hat.com>, Dave Young <dyoung@...hat.com>,
        Prarit Bhargava <prarit@...hat.com>,
        Junichi Nomura <j-nomura@...jp.nec.com>,
        Kiyoshi Ueda <k-ueda@...jp.nec.com>,
        Naoya Horiguchi <n-horiguchi@...jp.nec.com>
Subject: Re: [PATCH v2] x86/mce: Don't participate in rendezvous process once
 nmi_shootdown_cpus() was made

On Tue, Feb 21, 2017 at 08:37:21PM +0800, Xunlei Pang wrote:
> -    /* If this CPU is offline, just bail out. */
> -    if (cpu_is_offline(smp_processor_id())) {
> +    /*
> +     * Cases to bail out to avoid rendezvous process timeout:
> +     * 1)If crashing_cpu was set, e.g. entering kdump,
> +     *   we need to skip cpus remaining in 1st kernel.
> +     * 2)If this CPU is offline.
> +     */
> +    if (crashing_cpu != -1 ||
> +        cpu_is_offline(smp_processor_id())) {

You're still not letting the crashing_cpu enter the #MC handler. You
need to handle the MCE no matter how short the window is.

-- 
Regards/Gruss,
    Boris.

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