[CRIU] problem restoring process with alternate rootfs

[Tycho Andersen]

Hi all,

I'm having a problem restoring a process with an alternate root mount.
It has a /proc/$pid/mountinfo entry like:

66 40 253:1 /var/lib/lxc/u1/rootfs / rw,relatime - ext4 /dev/disk/by-uuid/86de4daf-7810-4422-804f-d1ab23ffd9fa rw,data=ordered

and when I try to restore it I get:

Error (files-reg.c:748): File /lib/x86_64-linux-gnu/libjson-c.so.2.0.0 has bad size 43464 (expect 39328)

libjson is 43k on my host and 39k in the lxc rootfs, so it seems criu
is trying to mmap the host's libjson instead of the container's. I'm
not entirely clear on what the bug is here, though; it looks like
__mntns_get_root_fd is looking at /proc/$pid/root, which for the
container process is just a link to /. I guess something about this /
remapping needs to be saved, but I'm not entirely sure what the right
approach is.

Thoughts?

Thanks,

Tycho