Re: [PATCH v2] powerpc/mce: log the error for all unrecoverable errors

[Ganesh G R <ganeshgr@linux.ibm.com>]

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On 1/31/23 4:59 PM, Michael Ellerman wrote:

> Ganesh Goudar<ganeshgr@linux.ibm.com>  writes:
>> For all unrecoverable errors we are missing to log the
>> error, Since machine_check_log_err() is not getting called
>> for unrecoverable errors.
>>
>> Raise irq work in save_mce_event() for unrecoverable errors,
>> So that we log the error from MCE event handling block in
>> timer handler.
> But the patch also removes the irq work raise from machine_check_ue_event().
>
> That's currently done unconditionally, regardless of the disposition. So
> doesn't this change also drop logging of recoverable UEs?
>
> Maybe that's OK, but the change log should explain it.

Yes, its ok, exception vector code will do that for recoverable errors, ill explain
this in commit message.

>
>> Log without this change
>>
>>   MCE: CPU27: machine check (Severe)  Real address Load/Store (foreign/control memory) [Not recovered]
>>   MCE: CPU27: PID: 10580 Comm: inject-ra-err NIP: [0000000010000df4]
>>   MCE: CPU27: Initiator CPU
>>   MCE: CPU27: Unknown
>>
>> Log with this change
>>
>>   MCE: CPU24: machine check (Severe)  Real address Load/Store (foreign/control memory) [Not recovered]
>>   MCE: CPU24: PID: 1589811 Comm: inject-ra-err NIP: [0000000010000e48]
>>   MCE: CPU24: Initiator CPU
>>   MCE: CPU24: Unknown
>>   RTAS: event: 5, Type: Platform Error (224), Severity: 3
>>
>> Signed-off-by: Ganesh Goudar<ganeshgr@linux.ibm.com>
>> Reviewed-by: Mahesh Salgaonkar<mahesh@linux.ibm.com>
>> ---
>> V2: Rephrasing the commit message.
>> ---
>>   arch/powerpc/kernel/mce.c | 8 +++++++-
>>   1 file changed, 7 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
>> index 6c5d30fba766..a1cb2172eb7b 100644
>> --- a/arch/powerpc/kernel/mce.c
>> +++ b/arch/powerpc/kernel/mce.c
>> @@ -131,6 +131,13 @@ void save_mce_event(struct pt_regs *regs, long handled,
>>   	if (mce->error_type == MCE_ERROR_TYPE_UE)
>>   		mce->u.ue_error.ignore_event = mce_err->ignore_event;
>>   
>> +	/*
>> +	 * Raise irq work, So that we don't miss to log the error for
>> +	 * unrecoverable errors.
>> +	 */
>> +	if (mce->disposition == MCE_DISPOSITION_NOT_RECOVERED)
>> +		mce_irq_work_queue();
>> +
>>   	if (!addr)
>>   		return;
>>   
>> @@ -235,7 +242,6 @@ static void machine_check_ue_event(struct machine_check_event *evt)
>>   	       evt, sizeof(*evt));
>>   
>>   	/* Queue work to process this event later. */
> This comment is meaningless without the function call it's commenting
> about, ie. the comment should be removed too.

ok.

Thanks.

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