[CRIU] Checkpointing failed

[Serge Hallyn]

Quoting Pavel Emelyanov (xemul at parallels.com):
> On 10/06/2014 09:18 PM, Thouraya TH wrote:
> > Hello :) Thanks for answer :)
> > 
> > root at u1:/# cd /sys/fs/fuse/connections
> > root at u1:/sys/fs/fuse/connections# ls
> > 30
> > root at u1:/sys/fs/fuse/connections# cd 30/
> > root at u1:/sys/fs/fuse/connections/30# ls
> > abort  congestion_threshold  max_background  waiting
> > 
> > root at u1:~# cat /proc/self/mountinfo
> > 69 52 8:1 /var/lib/lxc/u1/rootfs / rw,relatime - ext4 /dev/disk/by-uuid/afcb71d4-c111-4988-ae14-df81b2a06181 rw,errors=remount-ro,data=ordered
> > 70 69 0:32 / /proc rw,nosuid,nodev,noexec,relatime - proc proc rw
> > 71 69 0:33 / /sys rw,relatime - sysfs sysfs rw
> > 72 71 0:16 / /sys/fs/fuse/connections rw,relatime - fusectl none rw
> > 73 71 0:6 / /sys/kernel/debug rw,relatime - debugfs none rw
> > 74 71 0:10 / /sys/kernel/security rw,relatime - securityfs none rw
> > 75 71 0:14 /fs/pstore /sys/fs/pstore rw,nosuid,nodev,noexec,relatime - sysfs sysfs rw
> > 53 69 0:34 / /dev/pts rw,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=666
> > 54 69 0:34 /ptmx /dev/ptmx rw,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=666
> > 55 71 0:35 / /sys/fs/cgroup rw,relatime - tmpfs none rw,size=4k,mode=755
> > 56 69 0:36 / /run rw,nosuid,noexec,relatime - tmpfs none rw,size=97708k,mode=755
> > 57 56 0:37 / /run/lock rw,nosuid,nodev,noexec,relatime - tmpfs none rw,size=5120k
> > 58 56 0:38 / /run/shm rw,nosuid,nodev,relatime - tmpfs none rw
> > 59 56 0:39 / /run/user rw,nosuid,nodev,noexec,relatime - tmpfs none rw,size=102400k,mode=755
> 
> Ah I see. In the upstream kernel fuse and fusectl are not virtualized. So

This implies that (in openvz kernel) they are?  Url with more info?

> the latter fs when mounted inside container reveals fuse mounts from all
> the system. And criu fails to dump one, though none of the connections
> seen inside fusectl belong to this container.
> 
> Serge, Tycho, do you have any ideas what can we do about it?

Well Seth Forshee is working on patches to allow fuse mounts in user
namespaces, but AFAIK this is an aspect he hasn't touched.  And really
if he did he would probably set the nconnections per user-ns which wouldn't
help in this case anyway.

> Thouraya, I think for your experiments you can just umount the fusectl fs.
> 
> Thanks,
> Pavel
>