[CRIU] Dump problems

[Pavel Emelyanov]

On 08/19/2016 07:46 PM, Pavel Sanda wrote:
>> On 08/18/2016 10:07 AM, Pavel Sanda wrote:
>>> With debug on:
>>> ...
>>> (00.004603) Add pid ns 1 pid 5947
>>> (00.004608) Add net ns 2 pid 5947
>>> (00.004611) Add ipc ns 3 pid 5947
>>> (00.004615) Add uts ns 4 pid 5947
>>> (00.004618) Add mnt ns 5 pid 5947
>>> (00.004621) Add user ns 6 pid 5947
>>> (00.004624) Add cgroup ns 7 pid 5947
>>> (00.004625) cg: Dumping cgroups for 5947
>>> (00.004637) cg: Set 1 is criu one
>>> (00.004649) Warn  (ptrace.c:82): Unable to interrupt task: 4371 (Operation not permitted)
>>
>> That's the major obstacle -- you don't have permissions to ptrace the task you want.
>> Can you just strace -p $pid this task?
> 
> You are right, to provide security theatre performance my distro forbids ptracing,
> echo 0 > /proc/sys/kernel/yama/ptrace_scope fixes it.
> 
> Now we get little bit further:
> (00.003320) Collecting netns 2/18298
> (00.003702) Warn  (sk-unix.c:551): sk unix: Can't stat socket 0x18165(./run/user/105/pulse/native), skipping: Permission denied (err 13)
> (00.003724) Can't check shutdown state of inet socket
> (00.003740) Warn  (libnetlink.c:197): netlink: 16 bytes leftover after parsing attributes.
> (00.003802) Warn  (libnetlink.c:197): netlink: 16 bytes leftover after parsing attributes.
> (00.003868) Warn  (libnetlink.c:54): ERROR -16 reported by netlink
> (00.005627) Warn  (libnetlink.c:197): netlink: 28 bytes leftover after parsing attributes.
> (00.005647) Uncollected sockets! Will probably fail later.

That's ... a warning. Does dump really fail?

> Most probably pulseaudio, I will look if I can fix this.
> 
> Maybe this hint about ptrace could be added to the wiki.
> Also https://criu.org/CLI advice to use --ms parameter which no more works.

Thanks, fixed :)

> Pavel
> .
>