[CRIU] More uffd related questions (Error (page-read.c:128): Missing 7fff408d8000 in parent pagemap)

[Pavel Emelyanov]

On 11/30/2015 01:26 PM, Adrian Reber wrote:
> On Mon, Nov 30, 2015 at 01:24:30PM +0300, Pavel Emelyanov wrote:
>>
>>>> This is mm.img part, while page-read engine deals with pagemap-xxx.img files where
>>>> triplets of [start len in_parent] sit.
>>>
>>> Ah, okay. This is my error. The page I am trying to copy does indeed not
>>> exist in the pagemap:
>>>
>>>         {
>>>             "vaddr": "0x7f8025f6e000", 
>>>             "nr_pages": 5
>>>         }, 
>>>         {
>>>             "vaddr": "0x7fff408d9000", 
>>>             "nr_pages": 3
>>>         }, 
>>>         {
>>>             "vaddr": "0x7fff409c2000", 
>>>             "nr_pages": 2
>>>         }
>>>
>>> So to decide which pages I have to copy I only have to look at the content
>>> of pagemap-xxx.img and not mm.img, right? Good to know.
>>
>> Yes, the pagemap.img describes the physical memory dumped into the image files.
> 
> Going over all vma entries with something like
> 
>  list_for_each_entry(vma, vmas, list) {
> 
> How do I know if an area has been dumped or not? 

If it's on restore, then the list is likely got from image, isn't it?
On dump all vma's found in /proc/pid/maps is dumped.

> I am just starting to
> look at the code for this and have not found which flag/status is used
> to store this information.
> 
> 		Adrian
> .
>