linux-kernel - Re: [PATCH -v2] x86, MCE: Drop default decoding notifier

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Message-ID: <4DA5D9FB.1010503@redhat.com>
Date:	Wed, 13 Apr 2011 13:14:35 -0400
From:	Prarit Bhargava <prarit@...hat.com>
To:	Borislav Petkov <bp@...64.org>
CC:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Russ Anderson <rja@....com>,
	"Luck, Tony" <tony.luck@...el.com>,
	"dzickus@...hat.com" <dzickus@...hat.com>,
	"mstowe@...hat.com" <mstowe@...hat.com>,
	"dnelson@...hat.com" <dnelson@...hat.com>,
	"rja@...ricas.sgi.com" <rja@...ricas.sgi.com>
Subject: Re: [PATCH -v2] x86, MCE: Drop default decoding notifier



On 04/13/2011 01:01 PM, Prarit Bhargava wrote:
>   
>> @@ -239,7 +227,9 @@ static void print_mce(struct mce *m)
>>  	 * Print out human-readable details about the MCE error,
>>  	 * (if the CPU has an implementation for that)
>>  	 */
>> -	atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
>> +	ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
>> +	if (ret != NOTIFY_STOP)
>> +		pr_emerg(HW_ERR "Run the above through 'mcelog --ascii' to decode.\n");
>>  }
>>   
>>     
> Borislav,
>
>   

Oops.  Let me *carefully* rephrase that so it is clear what I'm
complaining about.

> I still think you need the check for UC here.  When an UC occurs and
> mce_panic() is called the output will include:
>
> [Hardware Error]:  Run the above through 'mcelog --ascii' to decode.
>
> potentially many, many times

for _all_ unreported *correctable* errors.

> .  The problem still is that there is no
> output to decode (in the default case).
>
>   

ie) (sorry for the cut-and-paste)

        /* First print corrected ones that are still unlogged */
        for (i = 0; i < MCE_LOG_LEN; i++) {
                struct mce *m = &mcelog.entry[i];
                if (!(m->status & MCI_STATUS_VAL))
                        continue;
                if (!(m->status & MCI_STATUS_UC)) {
                        print_mce(m);
                        if (!apei_err)
                                apei_err = apei_write_mce(m);
                }
        }

will potentially result in many bogus messages during a time at which we
definitely do not want bogus messages.

P.

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