[CRIU] Questions in CRIU restore mechanism.

[Chanho Park]

> > Thanks a lot for helping Chanho.
> > (He's stuck with another issue while testing CRIU anyway. :) )
> 
> Feel free to report all the issues to us. CRIU is in alpha stage yet, so
> we're ready for tons of new bugs and willing to have them fixed.

Hi Pavel,

I've run a simple test program on my ARM-based target.
The program is very simple. I want to check the criu is really working :)

test.c
#include <sys/types.h> 
#include <sys/stat.h> 
#include <stdio.h> 
#include <fcntl.h> 

int main()
{
    pid_t   pid;

    if (( pid = fork()) < 0)
   	    exit(0);

    else if(pid != 0)
        exit(0);

    close(0);
    close(1);
    close(2);
    setsid();
    while(1)
    {
	sleep(1);
    } 	
}


-sh-4.1# ./test
-sh-4.1# 
-sh-4.1# ps -ejH | grep test
 4875  4875  4875 ?        00:00:00   test
-sh-4.1# 
-sh-4.1# 
-sh-4.1# crtools dump -t 4875 -d chk/
(00.018153) Error (libnetlink.c:53): ERROR -2 reported by netlink
(00.037216) Warn  (cr-dump.c:1188): ptrace doesn't support
PTRACE_PEEKSIGINFO
(00.041969) Warn  (cr-dump.c:1188): ptrace doesn't support
PTRACE_PEEKSIGINFO

I found netlink error and some ptrace warning.

-sh-4.1# 
-sh-4.1# 
-sh-4.1# 
-sh-4.1# ps -ejH | grep test         
-sh-4.1# 
-sh-4.1# 
-sh-4.1# crtools restore -t 4875 -d chk/
(00.027441) Error (cr-restore.c:952): 4875 exited, status=4
(00.027736) Error (cr-restore.c:1259): Someone can't be restored

Restoration of the program is failed.

-sh-4.1# 
-sh-4.1# 
-sh-4.1# ps -ejH | grep test            
-sh-4.1# 
-sh-4.1# 

This is my kernel version
-sh-4.1# uname -a
Linux localhost 3.8.3-00828-g03d5607 #364 SMP PREEMPT Wed Mar 27 20:06:04
KST 2013 armv7l GNU/Linux

Here it is crtools check result:
-sh-4.1# crtools check
(00.015173) Error (libnetlink.c:53): ERROR -2 reported by netlink
The sock diag infrastructure is incomplete.
Make sure you have:
 1. *_DIAG kernel config options turned on;
 2. *_diag.ko modules loaded (if compiled as modules).
System call kcmp is not supported
(00.015847) Error (sk-tcp.c:693): Can't get TCP_TIMESTAMP: Protocol not
available
(00.017654) Error (cr-check.c:445): Unable to send siginfo with positive
si_code to itself: Input/output error
(00.018403) Error (cr-check.c:477): Unable to dump pending signals
: Input/output error

What am I doing wrong? Should I need to implement more things for ARM?

Best Regards,
Chanho Park