linux-kernel - Re: [PATCH 2/3] x86/mce: Fix incorrect "Machine check from unknown source" message

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Message-ID: <20180528204923.GB30792@zn.tnic>
Date:   Mon, 28 May 2018 22:49:23 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Tony Luck <tony.luck@...el.com>
Cc:     Dan Williams <dan.j.williams@...el.com>,
        Qiuxu Zhuo <qiuxu.zhuo@...el.com>,
        Ashok Raj <ashok.raj@...el.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] x86/mce: Fix incorrect "Machine check from unknown
 source" message

On Fri, May 25, 2018 at 02:41:55PM -0700, Tony Luck wrote:
> @@ -1287,12 +1292,17 @@ void do_machine_check(struct pt_regs *regs, long error_code)
>  			no_way_out = worst >= MCE_PANIC_SEVERITY;
>  	} else {
>  		/*
> -		 * Local MCE skipped calling mce_reign()
> -		 * If we found a fatal error, we need to panic here.
> +		 * If there was a fatal machine check we should have
> +		 * already called mce_panic earlier in this function.
> +		 * Since we re-read the banks, we might have found
> +		 * something new. Check again to see if we found a
> +		 * fatal error. We call "mce_severity()" again to
> +		 * make sure we have the right "msg".
>  		 */
> -		 if (worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3)
> -			mce_panic("Machine check from unknown source",
> -				NULL, NULL);
> +		if (worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3) {
> +			severity = mce_severity(&m, cfg->tolerant, &msg, true);
> +			mce_panic("Local fatal machine check!", &m, msg);

Haha, this would still make you look at the code to remember was it
"fatal local" or "local fatal" the second one. Yeah, there's the "!" but
still.

How about:

	"Fatal local machine check after banks scan"

or so.

Btw, the code in do_machine_check() has become one helluva spaghetti
mess. It could use some clean up a bit... :)

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--