[CRIU] [PATCH 1/2] finalize cgroups correctly

[Pavel Emelyanov]

On 03/19/2015 09:46 PM, Tycho Andersen wrote:
> On Thu, Mar 19, 2015 at 10:41:58AM -0700, Saied Kazemi wrote:
>> Hi Tycho,
>>
>> I tried the patch but it didn't work for me as cgyard is visible after
>> restore (please see below).  Here are criu dump and restore commands.  I've
>> also attached the log files.
>>
>> criu dump -v4 -D /home/saied/work/nsinit/busybox/nsinit/checkpoint -o
>> dump.log --root /home/saied/work/nsinit/busybox --manage-cgroups
>> --evasive-devices -t 31361
>>
>> criu restore -v4 -D /home/saied/work/nsinit/busybox/nsinit/checkpoint -o
>> restore.log --root /home/saied/work/nsinit/busybox --pidfile
>> /home/saied/work/nsinit/busybox/nsinit/restoredpid --manage-cgroups
>> --evasive-devices --inherit-fd fd[0]:pipe:[69253] --inherit-fd
>> fd[1]:pipe:[69254] --inherit-fd fd[2]:pipe:[69255]
>>
>> Any ideas why?!
> 
> I think it's because fini_cgroup is broken. It doesn't unmount the
> individual controllers before trying to unmount the cg yard.

That was done deliberately :) It does MNT_DETACH umount. Which, in
turn, detaches all the sub-mounts of the detached mount immediately :)

> Another problem I realized is that the properties restore code doesn't
> seem to respect the manage_cgroups flag (although I can't tell why it
> doesn't cause problems for more people, since it seems like it should
> blow up without that flag right now).

I guess it's because the list of controllers being empty without the
--manage-cgroups flag, is it?

> So, I think we need this patch but it isn't sufficient. We can drop
> the series for now and I'll try and come up with a patch to unmount
> things in the right order too.
> 
> Tycho

Thanks,
Pavel