Re: [PATCH] x86, mce: Don't initialize MCEs on unknown CPUs

[Ingo Molnar <mingo@elte.hu>]

* Andi Kleen <ak@linux.intel.com> wrote:

> Ingo Molnar wrote:
>
>>
>> btw., i found the bug - it's due to:
>>
>>   # CONFIG_CPU_SUP_INTEL is not set
>
> Ah, thanks for debugging. Very tricky and nasty. Perhaps these options are more trouble
> than what they save in code.
>
>>  static void __cpuinit mce_ancient_init(struct cpuinfo_x86 *c)
>> @@ -1342,11 +1352,10 @@ void __cpuinit mcheck_init(struct cpuinfo_x86 *c)
>>  	if (!mce_available(c))
>>  		return;
>>  -	if (mce_cap_init() < 0) {
>> +	if (mce_cap_init() < 0 || mce_cpu_quirks(c) < 0) {
>>  		mce_disabled = 1;
>>  		return;
>>  	}
>> -	mce_cpu_quirks(c);
>
> I'm very pedantic here and it's more a theoretical problem, but 
> mce_cap_init() allocates memory which you leak and this could 
> rerun on each CPU hotplug. So if you have a unknown CPU and do a 
> lot of CPU hotadds in a loop then you would eventually fill all 
> memory. Better kfree() the bank arrays.

Not really, we dont re-run mce_cap_init() if MCE is disabled so 
there's no memory leak that would fill all memory.

	Ingo