[CRIU] lxc-checkpoint 1.1.5 works with criu 1.6.1 but not master

[Adrian Reber]

Running lxc-checkpoint works with CRIU 1.6.1 but not with today's
master.

I get the following dump.log with today's master:

(00.000250) Probing sock diag modules
(00.000280) Done probing
(00.000283) ========================================
(00.000286) Dumping processes (pid: 10794)
(00.000287) ========================================
(00.000289) Running pre-dump scripts
(00.000315) Found anon-shmem device at 4
(00.000321) Reset 16059's dirty tracking
(00.000329) Warn  (mem.c:56): Can't reset 16059's dirty memory tracker (22)
(00.000341) Unlock network
(00.000347) Unfreezing tasks into 1
(00.000352) Error (cr-dump.c:1578): Dumping FAILED.


I get the following error with v1.8:

(00.000969) cg: Set 1 is criu one
(00.001276) Error (ptrace.c:64): suspending seccomp failed: Invalid argument
(00.001281) Unfreezing tasks into 1
(00.001282)     Unseizing 10794 into 1
(00.001284) Error (ptrace.c:54): Unable to detach from 10794: No such process
(00.001293) Unlock network
(00.001297) Unfreezing tasks into 1
(00.001298)     Unseizing 10794 into 1
(00.001299) Error (ptrace.c:54): Unable to detach from 10794: No such process
(00.001402) Error (cr-dump.c:1641): Dumping FAILED.

and it works with 1.6.1. I am running on CentOS 7.2 which has experimental CRIU
support but the kernel is not the newest: 3.10.0-327.4.4.el7.x86_64

With lxc-checkpoint and criu 1.6.1 I can migrate lxc containers from one host
to another. Unfortunately not back. The migration back to the original host
with criu 1.6.1 fails with:

(00.023469)      1:    [./sys/devices/virtual/net](192->172)
(00.023494)      1:     [./sys/devices/virtual/net](193->192)
(00.023496)      1:     <--
(00.023497)      1:    <--
(00.023498)      1:   <--
(00.023499)      1:  <--
(00.023500)      1: <--
(00.023507)      1: Start with 164:./
(00.023508)      1:     Mounting unsupported @./ (0)
(00.023509)      1: 164:./ private 0 shared 0 slave 1
(00.023513)      1:     Mounting tmpfs @./dev (0)
(00.024140)      1: Error (mount.c:1860): Can't mount at ./dev: Invalid argument
(00.024269) Error (cr-restore.c:1895): Restoring FAILED.

The first migration (host1 -> host2) works. Only back to host1 fails.
If I restore the image dumped on host2 also on host2 it also works.

Any ideas what might be wrong with my setup?

		Adrian