Re: [LTP] [linux-next:master] [mm/migrate] b28dd7507f: ltp.move_pages04.fail

[David Hildenbrand <david@redhat.com>]

On 28.08.24 14:23, Cyril Hrubis wrote:
> Hi!
>> I am not yet sure if we should simply allow either -EFAULT or -ENOENT for
>> the "nothing mapped" case in the check (below).
>>
>> Alternatively, I agree, wee need to have this in the kernel so we can
>> check for versions.
>>
>> What would be your preference?
> 
> If we are going to stick to ENOENT for page that wasn't faulted in the
> kernel from now on we should stick to it in the test as well.

Right, it will make kernels >= 4.3 fail, though, until this series is 
upstream. I mean, it highlights a BUG, but we had a similar condition 
with the zeropage and worked around it in the test to keep it passing.

> 
> Also I think there is a third case that we do not cover either, what
> happens when we pass an address that is not mapped at all, e.g. NULL? Do
> we get EFAULT as well?

Yes, that's documented as EFAULT and should behave that way. I can 
extend the test to handle that as well.

-- 
Cheers,

David / dhildenb