[CRIU] Restore of loginuid doesn't work

[Stanislav Kinsburskiy]

Hello,

I'm trying to run zdtm tests on Fedora 22, kernel 4.0.4., criu is up to 
date.
A bunch of tests are failing because of loginud restore.
All these tests are failing, when running in user namespace.
Here are examples:

=================== Run zdtm/live/static/write_read10 in uns 
===================
Start test
./write_read10 --pidfile=write_read10.pid --outfile=write_read10.out 
--filename=write_read10.test
Run criu dump
Run criu restore
=[log]=> dump/zdtm/live/static/write_read10/259/1/restore.log
------------------------ grep Error ------------------------
(00.341385)      5: Error (cr-restore.c:869): Can't open 5/loginuid on 
procfs: Permission denied
(00.341442)      4: Error (cr-restore.c:869): Can't open 4/loginuid on 
procfs: Permission denied
(00.350631) Error (cr-restore.c:1323): 280 exited, status=1
(00.350689) Error (files-reg.c:445):  `- XFail 
[/zdtm/live/static/write_read10.test.cr.1.ghost] ghost: No such file or 
directory
(00.350692) Error (files-reg.c:445):  `- XFail 
[/zdtm/live/static/write_read10.test.cr.1.ghost] ghost: No such file or 
directory
(00.362827) Error (cr-restore.c:2106): Restoring FAILED.
------------------------ ERROR OVER ------------------------
########### Test zdtm/live/static/write_read10 FAIL at CRIU restore 
############
##################################### FAIL 
#####################################

or this one:

================== Run zdtm/live/static/unlink_mmap00 in uns 
===================
Start test
./unlink_mmap00 --pidfile=unlink_mmap00.pid --outfile=unlink_mmap00.out 
--filename=unlink_mmap00.test
Run criu dump
Run criu restore
=[log]=> dump/zdtm/live/static/unlink_mmap00/256/1/restore.log
------------------------ grep Error ------------------------
(00.342840)      4: Error (cr-restore.c:869): Can't open 4/loginuid on 
procfs: Permission denied
(00.352313) Error (cr-restore.c:1323): 276 exited, status=1
(00.352373) Error (files-reg.c:445):  `- XFail 
[/zdtm/live/static/unlink_mmap00.test.cr.1.ghost] ghost: No such file or 
directory
(00.364723) Error (cr-restore.c:2106): Restoring FAILED.
------------------------ ERROR OVER ------------------------
########### Test zdtm/live/static/unlink_mmap00 FAIL at CRIU restore 
###########
##################################### FAIL 
#####################################