[CRIU] two runc related questions (-d and read-only)

[Adrian Reber]

I was trying to checkpoint and restore a runc container and so far I had
two smaller problems. My runc container has

	"terminal": false

and I am starting it detached '-d'. Checkpointing this container fails
if I run 'runc checkpoint --shell-job test' or without '--shell-job'
with following error:

(00.003008) 29213 fdinfo 0: pos: 0x               0 flags: 102002/0
(00.003022) tty: Dumping tty 8 with id 0x7
(00.003026) Error (files-reg.c:1141): Can't lookup mount=22 for fd=0 path=/dev/pts/2
(00.003029) ----------------------------------------
(00.003071) Error (cr-dump.c:1296): Dump files (pid: 29213) failed with -1

I get the same error using criu-2.4 and latest master. If I start the
container without '-d' I can checkpoint it without any problem.

Another problem I have seen is using runc with

	"readonly": true

this gives me following error:

(00.079785) Dumping task cwd id 0xb root id 0xb
(00.079931) mnt: Dumping mountpoints
(00.079934) mnt: 	213: 2b:/null @ ./proc/sched_debug
(00.079934) mnt: Something is mounted on top of ./dev
(00.080004) Error (criu/mount.c:1044): mnt: Can't create a temporary directory: Read-only file system

Starting the container with a read-write filesystem works.

I am curious why it fails for the detached and the read-only case. Is
this something that can be fixed?

		Adrian