[CRIU] Checkpointing LXC with external bind mount plugin

[Yuto KAWAMURA]

Hi,

I'm doing little experiment of checkpointing a lxc container which has
bind mounted pty from the host inside of it.
As already noted somewhere, I know that the external bind mount of the
lxc container can't be dumped without a plugin.
I wrote a plugin handles paths which has major number UNIX98_PTY_SLAVE_MAJOR.
After introduced this plugin, I'm not seeing an error such as
"/dev/ttyX doesn't have a proper root mount" anymore, but still I'm
getting an error:

  Error (tty.c:222): tty: Unexpected format on path /dev/tty1

I think this is because the path /dev/tty1 is still mounted after the
plugin handled it, and judged as a character device in
dump_one_file at files.c.
The question is, how to avoid this error? or am I understanding
something incorrect? or should I consider to make some changes to
criu?

I'm using the version HEAD of the criu git repository.

Regards,
Yuto