Re: [PATCH v4] memory_hotplug: Add a bounds check to __add_pages

[David Hildenbrand]

On 26.09.19 09:40, Oscar Salvador wrote:
> On Thu, Sep 26, 2019 at 11:34:05AM +1000, Alastair D'Silva wrote:
>> From: Alastair D'Silva <alastair@xxxxxxxxxxx>
>> @@ -291,6 +307,10 @@ int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
>>  	unsigned long nr, start_sec, end_sec;
>>  	struct vmem_altmap *altmap = restrictions->altmap;
>>  
>> +	err = check_hotplug_memory_addressable(pfn, nr_pages);
>> +	if (err)
>> +		return err;
>> +
> 
> I am probably off here because 1) I am jumping blind in a middle of a discussion and
> 2) I got back from holydays yesterday, so bear with me.
> 
> Would not be better to just place the check in add_memory_resource instead?

At least devmem/memremap needs special handling.

> Take into account that we create the memory mapping for this range in
> arch_add_memory, so it looks weird to me to create the mapping if we are going to
> fail right after because the range is simply off.
> 
> But as I said, I might be missing some previous discussion. 
> 


-- 

Thanks,

David / dhildenb