[CRIU] Re: [PATCH cr 07/16] restore: map private vma-s before forking children

[Pavel Emelyanov]

>>
>>> +			break;
>>> +		}
>>> +
>>> +	}
>>> +
>>> +	*pvma = list_entry(p->list.prev, struct vma_area, list);
>>
>> prev? Why prev? We should move forward the parent list. No?
> 
> list_for_each_entry_continue() starts from a next element, so we need to
> save prev here.

Indeed. Then the initialization of the pvma with _first_ element is wrong,
you should start with the list head instead.

>>
>>> +
>>> +		list_del(&p->list);
>>> +		xfree(p);
>>
>> Why do we remove parent vma from its list?
> 
> Then all unused parent's vma-s will be unmapped.

What do you mean by "unused"?

>>
>>> +	}
>>> +
>>> +	if (vma_entry_is(&vma->vma, VMA_FILE_PRIVATE))
>>> +		close(vma->vma.fd);
>>
>> Plz, explain this close.
> 
> This fd was opened upper and a vma was mapped and this fd isn't needed more.

Upper? Where is it?

>>
>>> +
>>> +		addr = (void *) vma_premmaped_start(&vma->vma);
>>> +		len = vma_area_len(vma);
>>> +
>>> +		if (!addr)
>>> +			continue;
>>> +
>>> +		if (munmap(addr, len)) {
>>
>> What is this munmap for?
> 
> Why do we need this vma-s, they were inherited from a parent.
> And one more thing is that all this vma-s will be inherited by
> children of this process and so on...

So this is unmap of all parent's maps, right? They were mapped with
one big chunk, why not unmapping them the same way?