linux-kernel - Re: [PATCH v6 1/2] ACPI / APEI: Add support to notify the vendor specific HW errors

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Date:   Tue, 31 Mar 2020 11:09:29 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     Shiju Jose <shiju.jose@...wei.com>
Cc:     "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
        "linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "rjw@...ysocki.net" <rjw@...ysocki.net>,
        "helgaas@...nel.org" <helgaas@...nel.org>,
        "lenb@...nel.org" <lenb@...nel.org>,
        "james.morse@....com" <james.morse@....com>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        "zhangliguang@...ux.alibaba.com" <zhangliguang@...ux.alibaba.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        Linuxarm <linuxarm@...wei.com>,
        Jonathan Cameron <jonathan.cameron@...wei.com>,
        tanxiaofei <tanxiaofei@...wei.com>,
        yangyicong <yangyicong@...wei.com>
Subject: Re: [PATCH v6 1/2] ACPI / APEI: Add support to notify the vendor
 specific HW errors

On Mon, Mar 30, 2020 at 03:44:29PM +0000, Shiju Jose wrote:
> 1. rasdaemon need not to print the vendor error data reported by the firmware if the 
>     kernel driver already print those information. In this case rasdaemon will only need to store
>     the decoded vendor error data to the SQL database.

Well, there's a problem with this:

rasdaemon printing != kernel driver printing

Because printing in dmesg would need people to go grep dmesg.

Printing through rasdaemon or any userspace agent, OTOH, is a lot more
flexible wrt analyzing and collecting those error records. Especially
if you are a data center admin and you want to collect all your error
records: grepping dmesg simply doesn't scale versus all the rasdaemon
agents reporting to a centrallized location.

> 2. If the vendor kernel driver want to report extra error information through
>     the vendor specific data (though presently we do not have any such use case) for the rasdamon to log. 
>     I think the error handled status useful to indicate that the kernel driver has filled the extra information and
>     rasdaemon to decode and log them after extra data specific validity check.

The kernel driver can report that extra information without the kernel
saying that the error was handled.

So I still see no sense for the kernel to tell userspace explicitly that
it handled the error. There might be a valid reason, though, of which I
cannot think of right now.

Thx.

-- 
Regards/Gruss,
    Boris.

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