linux-kernel - Re: [PATCH v3 2/2] x86/mce/dev-mcelog: Fix updating kflags in AMD systems

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Date:   Mon, 14 Sep 2020 17:34:20 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
Cc:     x86@...nel.org, linux-kernel@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-edac@...r.kernel.org,
        linux-efi@...r.kernel.org, linux-acpi@...r.kernel.org,
        devel@...ica.org, Tony Luck <tony.luck@...el.com>,
        "Rafael J . Wysocki" <rjw@...ysocki.net>,
        Len Brown <len.brown@...el.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Yazen Ghannam <yazen.ghannam@....com>
Subject: Re: [PATCH v3 2/2] x86/mce/dev-mcelog: Fix updating kflags in AMD
 systems

On Thu, Sep 03, 2020 at 06:45:31PM -0500, Smita Koralahalli wrote:
> The mcelog utility is not commonly used on AMD systems. Therefore, errors
> logged only by the dev_mce_log() notifier will be missed. This may occur
> if the EDAC modules are not loaded in which case it's preferable to print
> the error record by the default notifier.
> 
> However, the mce->kflags set by dev_mce_log() notifier makes the default
> notifier to skip over the errors assuming they are processed by
> dev_mce_log().
> 
> Do not update kflags in the dev_mce_log() notifier on AMD systems.
> 
> Signed-off-by: Smita Koralahalli <Smita.KoralahalliChannabasappa@....com>
> ---
> Link:
> https://lkml.kernel.org/r/20200828203332.11129-3-Smita.KoralahalliChannabasappa@amd.com
> 
> v3:
> 	No change
> v2:
> 	No change
> ---
>  arch/x86/kernel/cpu/mce/dev-mcelog.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kernel/cpu/mce/dev-mcelog.c b/arch/x86/kernel/cpu/mce/dev-mcelog.c
> index 03e51053592a..100fbeebdc72 100644
> --- a/arch/x86/kernel/cpu/mce/dev-mcelog.c
> +++ b/arch/x86/kernel/cpu/mce/dev-mcelog.c
> @@ -67,7 +67,9 @@ static int dev_mce_log(struct notifier_block *nb, unsigned long val,
>  unlock:
>  	mutex_unlock(&mce_chrdev_read_mutex);
>  
> -	mce->kflags |= MCE_HANDLED_MCELOG;
> +	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
> +		mce->kflags |= MCE_HANDLED_MCELOG;
> +
>  	return NOTIFY_OK;
>  }
>  
> -- 

This one is not related to your 1/2 so it sounds to me like I should
take this one now, independently?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette